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The Effect of Various Avocado Oils on Skin Collagen Metabolism
Abstract
The effects of various avocado oils on collagen metabolism in skin were studied in growing rats fed diets containing 10% (w/w) of the tested oils. Rats fed the unrefined avocado oil extracted with hexane from the intact fruit, its unsaponifiables or the avocado seed oil, showed significant increases in soluble collagen content in skin, though total collagen content was not affected. The increased soluble collagen content appears to be a consequence of the inhibition of lysyl oxidase activity. The active factor was found to be present in the unrefined avocado oil and probably originated from the avocado seed, since collagen metabolism was affected only by fractions which contained lipids fraction from the seed. In comparison rats fed the refined or unrefined soybean oils showed no effects.
... Avocado oil is obtained from the mesocarp and seed of the fruit of the avocado tree (Persea americana); avocado oil could serve as a food supplement in the diet due to the multiple benefits that its consumption confers on health. The inclusion of avocado oil in the diet improves the skin collagen metabolism [1], postprandial metabolic responses to a hypercaloric-hyperlipidemic meal in overweight subjects [2], the glucose and insulin resistance induced by high sucrose diet in Wistar rats [3]. Eight fatty acids are present in avocado flesh [4], including palmitic (C16:0), palmitoleic (C16:1), stearic (18:0), oleic (C18:1), and linoleic (18:2), myristic (C14:0), and arachidic (C20:0). ...
... In this way, the objectives of the present work are: (1) to examine the ability of the combination of phosphorylated starch, Gum Arabic, and HI-CAP ® 100 to emulsify avocado oil, (2) to evaluate the protection of these different polymers combination in microencapsulation process, and (3) to determine the critical storage conditions of avocado oil microparticles. ...
Avocado oil is a very valuable agro-industrial product which can be perishable in a short time if it is not stored in the right conditions. The encapsulation of the oils through the spray drying technique protects them from oxidation and facilitates their incorporation into different pharmaceutical products and food matrices; however, the selection of environmentally friendly emulsifiers is a great challenge. Four formulations of the following solid particles: Gum Arabic, HI-CAP®100 starch, and phosphorylated waxy maize starch, were selected to prepare avocado oil Pickering emulsions. Two of the formulations have the same composition, but one of them was emulsified by rotor-stator homogenization. The rest of the emulsions were emulsified by combining rotor-stator plus ultrasound methods. The protective effect of mixed particle emulsifiers in avocado oil encapsulated by spray drying was based on the efficiency of encapsulation. The best results were achieved when avocado oil was emulsified with a mixture of phosphorylated starch/HI-CAP®100, where it presented the highest encapsulation efficiency.
... Some authors [68][69][70] studied the relationship between avocado oil and collagen metabolism in both the skin and liver, finding that oil obtained from intact fruit (pulp and seed), refined with hexane, was associated with fibrosis in the liver, an increase in liver enzymes and consequently hepatotoxicity. ...
... Rats fed refined or unrefined soybean oils showed no effects. [70] Charles river female rats. ...
Avocado oil has generated growing interest among consumers due to its nutritional and technological characteristics, which is evidenced by an increase in the number of scientific articles that have been published on it. The purpose of the present research was to discuss the extraction methods, chemical composition, and various applications of avocado oil in the food and medicine industries. Our research was carried out through a systematic search in scientific databases. Even though there are no international regulations concerning the quality of avocado oil, some authors refer to the parameters used for olive oil, as stated by the Codex Alimentarius or the International Olive Oil Council. They indicate that the quality of avocado oil will depend on the quality and maturity of the fruit and the extraction technique in relation to temperature, solvents, and conservation. While the avocado fruit has been widely studied, there is a lack of knowledge about avocado oil and the potential health effects of consuming it. On the basis of the available data, avocado oil has established itself as an oil that has a very good nutritional value at low and high temperatures, with multiple technological applications that can be exploited for the benefit of its producers.
... Some authors [68][69][70] studied the relationship between avocado oil and collagen metabolism in both the skin and liver, finding that oil obtained from intact fruit (pulp and seed), refined with hexane, was associated with fibrosis in the liver, an increase in liver enzymes and consequently hepatotoxicity. ...
... Rats fed refined or unrefined soybean oils showed no effects. [70] Charles river female rats. ...
Avocado oil has generated growing interest among consumers due to its nutritional and technological characteristics, which is evidenced by an increase in the number of scientific articles that have been published on it. The purpose of the present research was to discuss the extraction methods, chemical composition, and various applications of avocado oil in the food and medicine industries. Our research was carried out through a systematic search in scientific databases. Even though there are no international regulations concerning the quality of avocado oil, some authors refer to the parameters used for olive oil, as stated by the Codex Alimentarius or the International Olive Oil Council. They indicate that the quality of avocado oil will depend on the quality and maturity of the fruit and the extraction technique in relation to temperature, solvents, and conservation. While the avocado fruit has been widely studied, there is a lack of knowledge about avocado oil and the potential health effects of consuming it. On the basis of the available data, avocado oil has established itself as an oil that has a very good nutritional value at low and high temperatures, with multiple technological applications that can be exploited for the benefit of its producers.
... In fact it induced an increase of soluble collagen and a decrease of insoluble collagen, as a result of the activation of connective tissue metabolism, mainly the inhibition of lysyl oxidase activity. The ASU action on the skin collagen metabolism may explain the beneficial effect on scleroderma observed by some authors [187][188][189]. An open-label, non-comparative study assessed efficacy and tolerability of a topical product containing avocado and soybean extracts and other lenitive and anti-oxidant principles administered for 24 weeks, in association with a dietary supplement containing avocado and soybean extracts vitamin E and para-aminobenzoic acid for the first 12 weeks, in the treatment of active mild-to-moderate VLS. ...
Vulvar lichen sclerosus (VLS) is a chronic, distressing, inflammatory disease with an enormous impact on quality of life. Treatment goals are relieving symptoms, reversing signs and preventing anatomical changes. Despite the availability of numerous therapeutic options, treatment outcome may not be entirely satisfactory and a definitive cure does not exist. This may be due to the fact that the exact VLS etiopathogenesis remains unknown. The objectives of this paper were to review the most up-to-date knowledge on VLS etiopathogenesis and to consider the available therapies through the lens of a plausible pathogenetic model. An electronic search on both VLS etiopathogenesis and its treatment was performed using the National Library of Medicine PubMed database. Based on current knowledge, it is conceivable that various, heterogeneous environmental factors acting on a genetic background trigger an autoimmune, Th-1 response, which leads to a chronic inflammatory state. This, in turn, can determine both tissue and micro-vascular injury and activation of signaling pathways involved in fibroblast and collagen metabolism. This pathogenetic sequence may explain the effectiveness of anti-inflammatory treatments, mostly topical corticosteroids, in improving VLS clinical-pathological changes. Further deepening of the disease pathways will presumably allow key mediators to become new therapeutic targets and optimize the available treatments.
... In cosmetics, avocado is valuable for its rejuvenate and moisturizing properties. In the study by Werman et al., avocado increased soluble collagen content of the skin (36). Suppressing fungal growth and helping the penetration of other antifungal agents is another effect of aloe vera plant (33) ...
: Chronic wound healing remains a complicated issue in the world's scientific health society. Alterations in the human body conditions such as biochemical, immunological, and physiological states may lead to non-healing wounds, making the treatment an insurmountably long and expensive procedure. Diabetes mellitus disposes the body to many complicated conditions while preventing diabetic wounds away from the normal wound-healing process. As topical administration is a favorable route of treating wounds, here, in this article, different topical materials and their roles are briefly reviewed.
... While dietary intake of olive oil has several beneficial effects on metabolic and skin health (Owen et al., 2000), its topical application is less effective due to its sensitizing or irritant effects (Kränke et al., 1997), and can be largely attributed to its polyphenol and squalene content. The beneficial effects of avocado oil on collagen metabolism (Werman et al., 1991), argan oil on cardiovascular health (Monfalouti et al., 2010), and oat lipids on keratinocyte differentiation (Chon et al., 2015) are also likely mediated by secondary bioactive compounds found in these oils. ...
Botanical oils have a long history of traditional use and are routinely applied to skin care. The focus of this review is to contrast the functionality of skin oils versus the differential biological and toxicological effects of major plant oils, and to correlate them to their compositional changes. In total, over 70 vegetable oils were clustered according to their lipid composition to promote awareness of health practitioners and botanical product manufacturers for the safety and efficacy of oil-based interventions based on their fatty acid profiles. Since multiple skin disorders result in depletion or disturbance of skin lipids, a tailored mixture of multiple botanical oils to simultaneously maintain natural skin-barrier function, promote repair and regeneration of wounded tissues, and achieve corrective modulation of immune disorders may be required. As bioactive constituents of botanical oils enter the human body by oral or topical application and often accumulate in measurable blood concentrations, there is also a critical need for monitoring their hazardous effects to reduce the possible over-added toxicity and promote maximal normal tissue sparing. The review also provides a useful tool to improve efficacy and functionality of fatty acid profiles in cosmetic applications.
... It is important to know that A/S is able to alter the cross-linking of collagen fibers and facilitate the wound-healing process. [11] It has been reported that arthrocen (an A/S unsaponifiable) has a potential to reduce joint inflammation and pain associated with end-stage osteoarthritis. [12] In a similar experiment, A/S (300 mg/day) was given to 4822 patients with symptomatic knee osteoarthritis as a routine medication. ...
Background: The use of stem cells, growth factors, and scaffolds to repair damaged tissues is a new idea in tissue engineering. The aim of the present study is the investigation of Avocado/soybean (A/S) effects on chondrogenic differentiation of human adipose-derived stem cells (hADSCs) in micromass culture to access cartilage tissue with high quality.
Materials and Methods: In this an experimental study After hADSCs characterization, chondrogenic differentiation was induced using transforming growth factor beta 1 (TGF-β1) (10 ng/ml) and different concentrations (5, 10, and 20 μg/ml) of A/S in micromass culture. The efficiency of A/S on specific gene expression (types I, II, and X collagens, SOX9, and aggrecan) was evaluated using quantitative polymerase chain reaction. In addition, histological study was done using hematoxylin and eosin and toluidine blue staining all data were analyzed using one-way analysis of variance (ANOVA) and P ≤ 0.05 was considered to be statistically significant.
Results: The results of this study indicated that A/S can promote chondrogenic differentiation in a dose-dependent manner. In particular, 5 ng/ml A/S showed the highest expression of type II collagen, SOX9, and aggrecan which are effective and important markers in chondrogenic differentiation. In addition, the expression of types I and X collagens which are hypertrophic and fibrous factors in chondrogenesis is lower in present of 5 ng/ml A/S compared with TGF-β1 group (P ≤ 0.05). Moreover, the sulfated glycosaminoglycans in the extracellular matrix and the presence of chondrocytes within lacuna were more prominent in 5 ng/ml A/S group than other groups.
Conclusion: It can be concluded that A/S similar to TGF-β1 is able to facilitate the chondrogenic differentiation of hADSCs and do not have adverse effects of TGF-β1. Thus, TGF-β1 can be replaced by A/S in the field of tissue engineering.
... Research on avocado seed extract has focused mainly on medical and cosmetic applications. These include studies on the antimicrobial potential, 106 skin and hair aerosol uses, 107 for hepatic collagen solubility, 108 skin collagen-metabolism, 109 and effects on liver disease. 110 Clearly wider applications for fatty acids from avocado seed extract may exist including their deployment in polymerization (See Section 3.1.6). ...
The food waste generated annually is approximately 1.3 Pg. It contains chemical feedstock that could be diverted to materials production as the mineral oil price rises, incurring no conflict over land use and providing new wealth-creating opportunities for food-producing countries. It potentially realigns the industrial and agricultural sectors of national economies. Food waste production scales with population as does demand for materials. This review builds upon previous landmark papers in Polymer Reviews that address biomass in polymer production. It surveys the current global food-waste resource and demonstrates how it could be used in the generation of hydrophobic polymers.
... Evaluation of collagen synthesis suggests greater stimulation at the higher doses. Similar results were found by Mauviel et al. (27) and Werman et al. (28) However, variation was seen between commercial product and Formula 1 preparations in the degree Values are the means AE SEM; ASU, avocado/soy unsaponifiables; a significant reduction of IL-1 induced increase in MMP or PGE2 expressed as pM/min/ml substrate conversion (n = 4) and pg PGE2/ 10 mg tissue (n = 8), respectively; SO 4 release expressed as% of total CPM incorporated released over 24 h (n = 8); b values significantly different from control (minus IL-1) cultures; na, not analyzed. of stimulation. ...
Avocado/soy unsaponifiable (ASU) components are reported to have a chondroprotective effect by virtue of anti-inflammatory and proanabolic effects on articular chondrocytes. The identity of the active component(s) remains unknown. In general, sterols, the major component of unsaponifiable plant material have been demonstrated to be anti-inflammatory in vitro and in animal models. These studies were designed to clarify whether the sterol content of ASU preparations were the primary contributors to biological activity in articular chondrocytes. ASU samples were analyzed by high pressure liquid chromatography (HPLC) and GC mass spectrometry. The sterol content was normalized between diverse samples prior to in vitro testing on bovine chondrocytes. Anabolic activity was monitored by uptake of 35-sulfate into proteoglycans and quantitation of labeled hydroxyproline and proline content after incubation with labeled proline. Anti-inflammatory activity was assayed by measuring reduction of interleukin-1 (IL-1)-induced synthesis of PGE2 and metalloproteases and release of label from tissue prelabeled with S-35.All ASU samples exerted a similar time-dependent up-regulation of 35-sulfate uptake in bovine cells reaching a maximum of greater than 100% after 72 h at sterol doses of 1-10 mug/ml. Non-collagenous protein (NCP) and collagen synthesis were similarly up-regulated. All ASU were equally effective in dose dependently inhibiting IL-1-induced MMP-3 activity (23-37%), labeled sulfate release (15-23%) and PGE2 synthesis (45-58%). Up-regulation of glycosaminoglycan and collagen synthesis and reduction of IL-1 effects in cartilage are consistent with chondroprotective activity. The similarity of activity of ASU from diverse sources when tested at equal sterol levels suggests sterols are important for biologic effects in articular chondrocytes.
The objective was to explore the relationship between the aging population, their nutritional needs and the contributions of the avocado, as well as to identify the demographic and socioeconomic profile of their consumers to delineate the productive scenario of this fruit in Mexico. The methodology was a statistical analysis with data from the National Health and Nutrition Survey 2012, to determine internal consumption, and with information from the Agri-Food and Fisheries Information Service and the National Agricultural Plan for the period 2017-2030, the production and export of the fruit. The results indicate that the lowest consumption of avocado is done in rural areas, among adults aged 60 and over, and in low and very low socioeconomic levels. In conclusion, the limited consumption in rural areas and among older adults is related to deficiencies in the distribution channels and the increase in the price of the product originated by export volumes. It requires the design of public policies to improve the access of older adults to this fruit given their nutritional needs.
Due to the various nutrients and vitamins that avocado presents, it is considered the healthiest fruit in the world. Of this fruit, only its pulp is used, generating tons of by-products in the form of shell and seed. The avocado seed (AS) represent up to 18% of the total weight of the fruit, even though it is a good source of protein and antioxidant compounds, is generally discarded, becoming a source of contamination. Therefore, a review of biotechnological applications of this by-product of avocado is shown, where its composition, antioxidant capacity, therapeutic and antimicrobial properties are considered, as well as its use in the removal of toxic compounds and for the production of biofuels, emphasizing its toxicological risks due their anti-nutrients. The biotechnological applications and patents described in this work demonstrate the economic potential of the AS.
Tree of the LAURACEAE family with straggling-ascending branches, usually up to about 15 meters high, sometimes much taller. Leaves spirally arranged, often clustered near the branch ends, narrowly to broadly elliptical or obovate, usually pointed at the tip, up to 20 cm long and over 15 cm broad, with well-developed petioles, glaucous beneath. Flowers in a much-branched compact panicle shorter than the leaves, greenish-yellow. Fruits variable in size and shape according to the variety, usually shiny and green or brownish when ripe, often pear-shaped, up to about 15 cm long; flesh soft, greenish or yellow, oily, surrounding one large loose round seed.
Objective
Limited evidence is available on the effectiveness of treatments alternative to corticosteroids for vulvar lichen sclerosus (VLS). The present study aimed to assess the efficacy and tolerability of avocado and soybean extracts (ASE) as active principles of both a topical product and a nutritional supplement in the treatment of active mild-to-moderate VLS.Materials and methodsTwenty-three patients were enrolled. Treatment consisted of a topical product containing ASE and other lenitive and anti-oxidant principles administered twice daily for 24 weeks, in association with a dietary supplement containing ASE, vitamin E and para-aminobenzoic acid for the first 12 weeks. The primary efficacy endpoint was the rate of patients achieving an improvement from baseline in global subjective score (GSS) and global objective score (GOS) of ≥ 75%. Secondary efficacy endpoint was the rate of patients achieving GSS50 and GOS50. Tertiary efficacy endpoint was the mean reduction in subjective and objective scores throughout the treatment.ResultsBy the end of the 24-week treatment, 12 (70.5% of symptomatic patients) and 13 patients (72.2%) achieved an improvement of at least 75% in subjective and objective global scores, respectively; 100% and 88.9% reached GSS50 and GOS50, respectively. Mean symptom and sign scores decreased significantly after treatment. The treatment was well tolerated.Conclusions
Our results provide evidence that the topical and dietary supplements used in the study, which contain active principles exerting anti-inflammatory, anti-fibrotic, emollient and lenitive actions, are effective alternatives in the treatment of symptoms and signs of mild-to-moderate VLS.
Copper deficiency is characterized by multiple connective tissue manifestations, such as skeletal and joint abnormalities, and vascular lesions that lead to aneurysms and aortic rupture. However, the rupture of the heart observed in cooper-deficient male rats is not fully understood. We demonstrated the effect of copper deficiency on cardiac collagen content and solubility, regional differences in cardiac lysyl oxidase activity, collagen cross-links, and on the ultrastructural morphology of collagen in the myocardium. Weaned male rats fed copper-deficient or copper-adequate diets were examined. Copper-deficient rats died prematurely of heart rupture at the apex, and those who survived exhibited heart enlargement, decreased cardiac lysyl oxidase activity with increasing heart soluble collagen content. Mature collagen cross-links, as assessed by the concentrations of pyridinoline and deoxypyridinoline, were lower both in the apex and in the right and left ventricles of copperdeficient rats as compared with copper-adequate controls. However, in copper-deficient rats, cross-links levels were significantly lower at the apex than at the left and right ventricles. In addition, severe ultrastructural abnormalities in the size and shape of endo-and epimysium collagen fibers were observed in the apex of copper-deficient rats. Transmission electron microscopy showed giant, spiralled or frayed, and spiny collagen fibers. These findings allow us to postulate that the reduced cardiac lysyl oxidase activity accompanied by altered collagen cross-links and an abnormal connective tissue ultrastructure play a significant role in the manifestation of copper deficiency in the male rat.
More than three decades ago, Kashman and coworkers (1,2) reported for the first time a class of closely related compounds from avocados (Lauraceae). This class of compounds contains several highly oxygenated long-chain acetylenic and olefinic natural products derived from fatty acids (e.g. possibly C-18 oleic, linoleic, linolenic, or stearic acid as precursors). These products form part of a group of compounds known as the biologically active aliphatic acetogenins, the distribution of which is thought to be restricted to the Annonaceae and Lauraceae. Current studies indicate that the Lauraceous acetogenins are synthesized during early plant development from specialized idioblast oil cells and transported from the oil cells to other parts of the plant. While idioblast oil cells are found throughout the plant kingdom, their function in many plant families has been the focus of considerable speculation because little is known about the chemistry or biological activity of the oil in the cells. Until recently, the idioblast cells were generally viewed simply as unusual storage organs. In avocados, increasing evidence indicates that the cells, and the oil they contain, may play an important defensive role against pathogens and insects. Several of the compounds produced in avocado oil cells, reported to occur almost exclusively in the genus Persea, are now known to have antibacterial, antifungal, and insecticidal activity. In the present paper we review the distribution, synthesis, biological activity, and mode of action of the most studied Lauraceous acetogenins the diene persin, (12Z, 5Z)-1-acetoxy-2-hydroxy-4-oxo-heneicosa-12,15-diene, and the persin-derived furans known as avocadofurans.
A new natural inhibitor of lysyl oxidase was separated by thin-layer chromatography from avocado seed oil. This compound, called component C, is unique to the avocado seed. It has a molecular weight of 248 and is extracted from the unsaponifiable matter. Of all seed oil unsaponifiables, only component C was found to inhibit rat skin and check tibia lysyl oxidase activity. The in vitro inhibitory effects of component C on rat skin lysyl oxidase activity was similar to that of seed oil and revealed an I50 of 1mM.
The active factor of lysyl oxidase inhibition was separated from unsaponifiables of avocado seed oil and characterized by
gas chromatography-mass spectrometry. Results indicated the presence of furan-containing lipids in the active factor mixture
and also showed a structural difference compared to previously reported furan-containing lipids of avocado which relates to
the length of the hydrocarbon chain substituent. Another structural difference evinced was the availability of the hydroxyl
group in the aliphatic moiety of the investigated substances. A purified mixture of furan-containing compounds was testedin vitro for inhibitory activity on pure bovine aorta lysyl oxidase. It was shown that mixing furan-containing lipids in Tween 80
reversibly inhibited pure bovine aorta lysyl oxidase activity against tritiated recombinant tropoelastin with the I50 value of inhibition of 105 µM. Thesein vitro studies suggested that the mixture of avocado seed oil furan-containing lipids was not a substrate-specific inhibitor of
lysyl oxidase, and it might prove to be useful as a potential antifibrotic drug. Moreover, the unique chemistry of the studied
compound for lysyl oxidase inhibition should enable the designing of new probes of the active site of this important enzyme.
The effect of various avocado and soybean oils on collagen metabolism in the liver was studied in growing female rats for 8 weeks and in day-old chicks for 1 week. In comparison with rats fed either refined avocado oil, refined or unrefined soybean oils, rats fed unrefined avocado oil showed a significant decrease in total collagen solubility in the liver, while there were no changes in total collagen, protein and moisture content. Chicks fed unrefined avocado oil as compared to those fed refined avocado oil also showed a decrease in hepatic total soluble collagen while hepatic total collagen remained unaffected. Electron micrographs and light-microscope examinations of rats' liver revealed collagen accumulation in the periportal location. This is suggestive of the early stages of fibrosis.
Objective:
Avocado and soya unsaponifiables (ASU) have been reported to exert beneficial effects in the treatment of periodontal and osteoarticular diseases. They are supposed to stimulate deposition and repair of extracellular matrix components, but the mechanisms underlying their action are not well understood. In view of the repair potential of osteoarthritic (OA) cartilage and the role that the transforming growth factor beta (TGFbeta) system could play in that process, we carried out in vitro studies to determine the mechanism of action of ASU on articular chondrocytes that may account for the beneficial effects on cartilage metabolism.
Methods:
Cultured bovine articular chondrocytes were treated with various concentrations of ASU, and the expression of both TGFbeta isoforms, 1 and 2, and their receptors (TGFbetaRI and TGFbetaRII) was determined by Northern blot and reverse transcriptase-polymerase chain reaction. Cell transfection with TGFbeta1 promoter constructs was also used to delineate the cis-acting sequences mediating ASU responsiveness in chondrocytes. The level of plasminogen activator inhibitor 1 (PAI-1) was also evaluated by Northern blotting and protein radiolabeling.
Results:
The data indicated that ASU stimulate the expression of TGFbeta1, TGFbeta2, and PAI-1 by articular chondrocytes. In contrast, the levels of TGFbetaRI and TGFbetaRII were not significantly affected by the compound. Treatment of bovine articular chondrocytes transiently transfected with TGFbeta1 promoter constructs suggested that the effect on TGFbeta1 expression is mediated by the region located between -732 and -1132 bp.
Conclusion:
The results indicate that the ASU-induced stimulation of matrix synthesis previously reported in cultured articular chondrocytes could be explained by the ability to enhance TGFbeta expression in these cells. Further, ASU increase the production of PAI-1, an effect that could help in blocking the plasmin cascade that leads to metalloprotease activation. These data suggest that the compound has properties that might promote TGFbeta-induced matrix repair mechanisms in articular cartilage.
To determine the relationship between matrix metalloproteinases (MMPs), their inhibitors, and the turnover of matrix molecules in articular cartilage from patients with osteoarthritis (OA).
Synovial fluid samples were collected from the knees of 54 patients with OA. Radiographic evaluations and magnetic resonance imaging were performed on the knees of 34 OA patients to classify the stage of the disease. Biochemical analyses and immunoassays were used to measure the concentrations of MMP-1, MMP-3, tissue inhibitor of metalloproteinases 1 (TIMP-1), TIMP-2, the disaccharide of hyaluronic acid, the proteoglycan glycosaminoglycan disaccharides of chondroitin 4-sulfate (delta di-CS4) and chondroitin 6-sulfate (delta di-CS6), the 846 epitope on chondroitin sulfate of cartilage proteoglycan aggrecan (putative biosynthetic marker), the keratan sulfate (KS) epitope of aggrecan (putative degradation marker), and the C-propeptide of cartilage type II procollagen (CPII) (biosynthetic marker).
The concentration of TIMP-1 was directly correlated with the levels of MMP-1 and MMP-3 (both were also correlated with each other), confirming earlier results. There was an inverse correlation between the delta di-CS6:delta di-CS4 ratio and the concentration of MMP-3. The level of delta di-CS6 was correlated with that of the KS epitope, and to a lesser degree, with that of the 846 epitope (the latter was also correlated with the level of delta di-CS4). The concentration of TIMP-1 correlated with that of the 846 epitope, whereas TIMP-2 levels correlated with those of CPII. There were significantly lower concentrations of delta di-CS6, delta di-CS4, the 846 epitope, and CPII in synovial fluid from patients with late-stage OA.
These observations suggest a link between proteolysis and inhibitor concentrations in OA cartilage. Production of TIMPs appears to be individually linked to the synthesis of specific cartilage molecules. The reduction in the amount of cartilage-matrix structural components suggests that there is a measurable loss of cartilage in the late stages of the disease, as suggested previously. The resultant composition of the cartilage suggests that the loss may primarily involve "resident" molecules originally present in healthy cartilage.
In periodontal disease, interleukin-1beta (IL-1beta) is responsible for the matrix breakdown through excessive production of degrading enzymes by periodontal ligament fibroblasts and osteoblasts. Transforming growth factor-beta (TGF-beta) plays an important role in tissue regeneration as one of the factors capable of counteracting IL-1beta effects. In this study, we investigated the in vitro effect of avocado and soya unsaponifiables (ASU) on the expression of TGF-beta1, TGF-beta2, and bone morphogenetic protein-2 (BMP-2) by human periodontal ligament (HPL) and human alveolar bone (HAB) cells in the presence of IL-1beta.
HPL and HAB cells were incubated for 48 hours with ASU (10 microg/ml) in the presence or absence of IL-1beta (10 ng/ml). The steady-state levels of TGF-beta1, TGF-beta2, and BMP-2 mRNAs were determined by Northern blot or reverse transcription-polymerase chain reaction (RT-PCR). The amounts of TGF-beta1 and TGF-beta2 proteins were measured by enzyme-linked immunosorbent assay (ELISA).
The data indicated that IL-1beta strongly decreases the expression of TGF-beta1 and TGF-beta2 by HPL cells. ASU were capable of opposing the cytokine effect. In HAB cells, TGF-beta1 and BMP-2 mRNA levels were downregulated by the cytokine. ASU were found to reverse the IL-1beta-inhibiting effect. In contrast, the cytokine stimulated the production of TGF-beta2 in alveolar bone cells, with no significant effect of ASU.
The results indicate that the IL-1beta-driven erosive effect in periodontitis could be enhanced by a decreased expression of members of the TGF-beta family. The ASU stimulation of TGF-beta1, TGF-beta2, and BMP-2 expression may explain their promoting effects in the treatment of periodontal disorders, at least partly. These findings support the hypothesis that ASU could exert a preventive action on the deleterious effects exerted by IL-1beta in periodontal diseases.
The administration of penicillamine to rats causes an accumulation of soluble collagen in soft tissues. The preponderance of α components in the tropocollagen subunits isolated indicates a lack of intramolecular cross-links, while the marked solubility of the collagen fibers in 0.5 M NaCl reflects the absence of covalent intermolecular bonds. Penicillamine does not affect the rate of synthesis of tropocollagen, but blocks almost quantitatively the formation of new insoluble collagen. In addition, it accelerates the turnover of the pre-existing insoluble material by presumably cleaving intermolecular bonds, which stabilize the fibrous structure. It will inhibit or retard fibrillogenesis in vitro, or cause a redissolution of the formed fibers upon cooling, depending on its concentration in the medium.
The administration of penicillamine to rats causes an accumulation of soluble collagen in soft tissues. The preponderance
of α components in the tropocollagen subunits isolated indicates a lack of intramolecular cross-links, while the marked solubility
of the collagen fibers in 0.5 m NaCl reflects the absence of covalent intermolecular bonds. Penicillamine does not affect the rate of synthesis of tropocollagen,
but blocks almost quantitatively the formation of new insoluble collagen. In addition, it accelerates the turnover of the
pre-existing insoluble material by presumably cleaving intermolecular bonds, which stabilize the fibrous structure. It will
inhibit or retard fibrillogenesis in vitro, or cause a redissolution of the formed fibers upon cooling, depending on its concentration in the medium.
In these comments, the cross-linking of two connective tissue proteins, elastin and collagen have been discussed. Emphasis will be placed on lysine-derived cross-links, since their synthesis may be modified by changes in diet. The authors also point out some of the pitfalls in assessing the nature or quantifying the amounts of cross-linking amino acids.
Genetic defects at the level of transscription and translation may explain why very little type II procollagen is synthesized by patients with type IV of Ehlers-Danlos syndrome. Similary defect synthesis of type I collagen may explain the decrease in the ratio of type I collagen to type III collagen in osteogenesis imperfecta. The synthesized type I collagen in this disorder is unusually sensitive to pepsin, possibly due to an amino acid substitution in the pro-alpha chain of type I procollagen. Defects in intracellular processing include a decrease in lysyl hydroxylase in the type VI variant of Ehlers-Danlos syndrome. Defects in extracellular processing include a decrease in procollagen aminoprotease seen in dermatosparexis and in Ehlers-Danlos syndrome type VII. A deficiency in the enzyme lysyl oxidase is seen in type V Ehlers-Danlos syndrome. A defective cross-linking of collagen may also explain the tissue changes in Marfan's syndrome and in homocysteinuria. Mechanisms for gene selection of collagen may be influenced by environmental factors such as lysosomal enzymes which can change the collagen synthesized by chondrocytes from type II to type I. Scurvy is a classical example of how collagen biosynthesis can be altered at the posttranslational level. Several agents have been used in an attempt to inhibit fibrosis. Glucocorticosteroids can inhibit the synthesis of collagen and other proteins. Penicillamin and beta-aminopropionitrile can inhibit the cross-linking of collagen, the latter via and inhibition of lysyl oxidase. Prolin analogues as cis-hydroxyprolin have been used to inhibit the intracellular post-translational enzymes. Colchicine disrupts microtubules and slows the rate of secretion of procollagen and it may also increase the secretion of collagenase.
After prolonged exposure to ascorbate, collagen synthesis in cultured human skin fibroblasts increased approximately 8-fold with no significant change in synthesis of noncollagen protein. This effect of ascorbate appears to be unrelated to its cofactor function in collagen hydroxylation. The collagenous protein secreted in the absence of added ascorbate was normal in hydroxylysine but was mildly deficient in hydroxyproline. In parallel experiments, lysine hydroxylase (peptidyllysine, 2-oxoglutarate:oxygen 5-oxidoreductase, EC 1.14.11.4) activity increased 3-fold in response to ascorbate administration whereas proline hydroxylase (prolyl-glycyl-peptide, 2-oxoglutarate:oxygen oxidoreductase, EC 1.14.11.2) activity decreased considerably. These results suggest that collage polypeptide synthesis, posttranslational hydroxylations, and activities of the two hydroxylases are independently regulated by ascorbate.
The effect of a vitamin E-deficient diet on muscular collagen was studied in young rabbits. Intramuscular collagen content was found to increase in vitamin E-deficient rabbits, both in absolute and relative values, while no changes in urinary hydroxyproline excretion were observed. The overall solubility of intramuscular collagen was higher and the collagen soluble in guanidine hydrochloride was richer in alpha-chains. Such findings would suggest that avitaminosis E induces the production of new intramuscular collagen.
The influence of high (45%) and low (8%) levels of dietary protein on the biosynthesis and cross linking of skin and muscle collagen was investigated. The yield of salt soluble collagen was decreased 35% in the low protein group and 11% in the high group as compared to animals on the 25% casein control diets. Total muscle collagen synthetic activity per g muscle was markedly lower in both the 8 and 45% protein groups. The incorporation of L [U 14C] leucine into collagen per mg muscle polyribosomal RNA was reduced 42 and 22%, respectively, in animals maintained on the 8 and 45% protein diets. The incorporation of [2 14C] glycine in skin was reduced 46% for the low and 23% for the high protein fed animals as compared to the controls; reductions of 35 and 33%, respectively, were also found for L [U 14C] proline incorporation. The aldehyde content of the α1 chains from animals on the 8% protein diet was elevated in comparison to those on the 45% and control diets while the yield of intramolecularly cross linked β components was reduced by 48%. No variation in yield of acid soluble collagen, thermal shrinkage temperature or amino acid composition of the α1 chains was apparent between diet groups.
Eight new compounds have been isolated and identified from avocado fruit and seeds. Their structures were determined by chemical as well as by spectroscopic means. All compounds have been interconverted and shown to belong to the same group of long chain aliphatic compounds, constituting four pairs. Each pair contains two compounds which differ only in having a double or triple bond at the end of the chain.
A new natural inhibitor of lysyl oxidase was separated by thin-layer chromatography from avocado seed oil. This compound, called component C, is unique to the avocado seed. It has a molecular weight of 248 and is extracted from the unsaponifiable matter. Of all seed oil unsaponifiables, only component C was found to inhibit rat skin and check tibia lysyl oxidase activity. The in vitro inhibitory effects of component C on rat skin lysyl oxidase activity was similar to that of seed oil and revealed an I50 of 1mM.
The configuration of some of the new compounds reported previously,1 to be isolated from avocado has been elucidated by synthesising the carbonate, acetonide and sulfites of one of the compounds. The characterisation of several other compounds of the same group is reported.
SynopsisThe unsaponifiable lipidic fractions of avocado and soya bean were administered percutaneously, on the dorsal skin of hairless rats for 15 days, in a 5% sweet almond oil solution. This treatment produced a modification of dermal connective tissue components. The biochemical analysis showed an increase of soluble proteins, especially of salt soluble collagen together with a decrease of proteins insoluble in neutral buffer. The ratio, soluble proteins:insoluble proteins, increases as well as the ratio soluble collagen: insoluble collagen. These modifications can be considered as a result of the activation of connective tissue metabolism.The above results are in agreement with those obtained when the unsaponifiables were administered per os to rats.Effets biochimiques, sur le tissu conjonctif sous cutané des insaponifiables de soja et d'avocat adminstrés par voie percutanée chez le rat sans poilsRésuméL'application parvoie percutanée durant 15 jours d'un mélange d'insaponifiables d'avocat et de soja en solution à 5% dans l'huile d'amande douce entraîne des modifications des constituants du tissu conjonctif cutané. Leur dosage a permis la mise en évidence d'une augmentation des protéines solubles, notamment du collagène et d'une diminution simultanèe des protéines insolubles. Les rapports protéines solubles:protéines insolubles et collagène soluble:collagène insoluble sont accrus; ils traduisent l'activation du métablisme du tissu conjonctif.Ces résultats sont en accord avec ceux obtenus lorsque les insaponifiables sont administrés par voie orale chez le rat.
Centrifugal force separation is a relatively new industrial process for extracting avocado oil. This study examined the influences
of temperature, pH and NaCl concentration on oil extraction efficiency by centrifugal processing. Optimal separation conditions
occurred at 75 C, with a pH of 5.5 and NaCl concentration of 5%.
Differences in chemical characteristics exist between avocado oils produced by industrial processes and those oils that were
produced in the laboratory by organic solvent extraction. The highest amount of chlorophyll, 192.9 ppm, was obtained by ethanolic
extraction in the laboratory. Unsaponifiables content reached 1.95% in industrial oil produced by organic solvent extraction.
The highest acid value, 8.35, was obtained from industrial oil produced by centrifugal separation. Hydroxyl values in our
oils were found to be 2–3 times higher than those reported in the literature.
The quantitative relationships were determined between the structural crosslinks, dihydroxylysinonorleucine (Lys(OH)2-Nle) and hydroxylysinonorleucine (Lys(OH)-Nle) in NaB 3H4-reduced diaphyseal bone collagen from 1-, 2-, 3- and 4-week-old chicks fed either a vitamin D-deficient diet, a normal-vitamin D diet or a high-, but non-toxic, vitamin D diet from time of hatching. Chicks fed the normal diet showed a progressive decrease in the ratio of Lys(OH)2-Nle/Lys(OH)-Nle with age. This decrease was accelerated in chicks receiving the High-vitamin D diet. In the vitamin D-deficient group, the ratio was higher than controls at 1 and 2 weeks and increased further at 3 and 4 weeks. Similar changes in Lys(OH)2-Nle/Lys(OH)-Nle ratio did not occur in skin collagen. Compared to Control-vitamin D animals, the increased crosslink ratios in the vitamin D-deficient bone collagen occurred prior to changes in growth rate and could not be correlated with lysine hydroxylation or the hypocalcemia seen in this group. These results suggest that the type of crosslink analysis used in this study provides one of the earliest and most sensitive indications of a bone disturbance due to vitamin D deficiency and that vitamin D specifically acts to increase the rate of maturation of bone collagen.
Intratracheal administration of bleomycin caused pulmonary fibrosis in rats. Bleomycin sulfate (640 micro grams/165 g b.wt. in 0.5 ml of sterile saline) was instilled Intratracheally into male Fisher 344 rats (169 +/- 5 g), whereas control animals received 0.5 ml of sterile saline by the same route. One, 3, 7, 14, 28 and 322 days after instillation, the animals were killed, the lungs were homogenized in 6 M urea, 0.01 M NaCl, 0.001 M potassium phosphate (pH 8.3) and the homogenates were subjected to ultracentrifugation. The 106,000 x g supernate was assayed for lysyl oxidase activity. Total lung hydroxyproline and desmosine content was determined at each time point. Lysyl oxidase specific activity in the lung was elevated significantly 3 days after bleomycin treatment, peaked 14 days after bleomycin treatment at 230% above the control value and was returned toward normal 28 days after treatment. The increase of lysyl oxidase activity preceded the maximal increase of total lung hydroxyproline and desmosine which occurred 28 days after bleomycin instillation.
Synopsis The non-saponifiable lipidic fractions of avocado and soya bean applied percutaneously to hairless rats for 15 days had been shown to produce biochemical modifications of dermal connective tissue components: increases of soluble collagen and of the ratio soluble collagen/insoluble collagen. In this present study, we tried to show whether these biochemical modifications could be confirmed by biophysical analytical methods and could affect the biochemical properties of the skin. The experiments were carried out on three groups of rats treated by application to the dorsal skin, either with 0.9% NaCl (control), or sweet almond oil (vehicle), or with a mixture of 2/3 soya bean and 1/3 avocado in solution at 5% of sweet almond oil (treated group). After 15 days treatment, the rats were killed and the skin of the treated area dissected. X-ray diffraction diagrams were recorded by varying the position of previously dried samples in controlled conditions. Results indicated that the vehicle decreased the orientation degree of collagen fibres, acting on their reticulation. The addition of the non-saponifiable fraction did not significantly add to the vehicle effect. The study of thermostability of the cutaneous collagen by differential scanning calorimetry showed that non-saponifiables increased the slope of the rise of temperature of denaturation. The quantity of heat absorbed during the denaturation (enthalpy variation) reached around 0.04 J mg(-1) of collagen in the control groups and did not exceed 0.03 J mg(-1) of collagen in the treated ones. Taken in conjunction with previous work it is probable that the non-saponifiables increase the proportion of soluble collagen. The elasticity of whole skin, determined by a static method using an Instron exten-siometer was significantly modified by treatment with non-saponifiables. They produced a decrease of the elasticity module. These results correspond to a decrease of collagen reticulation degree.
A simplified method for the assay of lysyl oxidase activity was developed. The method is based on the measurement of tritiated water released by enzyme action from labeled protein-bound lysine and hydroxylysine. Trichloroacetic acid (TCA) supernates of the incubation mixtures are passed through small Dowex 50 (H+) columns and the effluents are counted. For rapid screening purposes an indication of the presence of enzyme activity in enzyme preparations can be obtained by measuring the radioactivity present in aliquots of the TCA supernates as such and by measuring the radioactivity after drying at 60°C, taking the difference between the two as a measurement of enzyme activity.
Copper deficiency initiates extensive pathological changes in the major arteries of young chicks and pigs. These changes for the most part are localized within the elastic fibers in the vessel wall. Scanning electron micrographs of copper deficient chick aortas revealed randomly oriented fibrous ridges unevenly dispersed throughout the tunica media as well as structurally modified, stunted elastic fibers. A key role for copper in aorta is that of a cofactor for the enzyme lysyl oxidase. The enzyme catalyzes formation of desmosine and isodesmosine, and hence takes part in the polymerization of proelastin into mature elastic fibers. Besides serving as cofactor, copper may also regulate lysyl oxidase levels in aorta. Evidence supportive of this role has come from dietary studies where it was observed that chicks fed copper deficient diets suffered a rapid decline of lysyl oxidase activity. The enzyme activity was almost undetectable in aorta after 8 days — the time overt symptoms of the deficiency first appear. Returning copper to the diet restored complete enzymatic function.
Lysyl oxidase catalyzes the initial reaction in the biosynthesis of collagen and elastin cross-links. The enzyme is a specific, extracellular amine oxidase probably related to the diamine oxidases (EC 1.4.3.6) but may be in a separate class. Copper and probably pyridoxal are co-factors, and molecular oxygen is the probable cosubstrate and hydrogen acceptor. It is irreversibly inhibited by micromolar concentrations of lathyrogens. Purification in urea-containing buffers has yielded multiple forms with similar substrate specificity for collagen and elastin. Highly purified lysyl oxidase has highest activity with reconstituted collagen fibrils, elastin coacervates, and possibly other ordered molecular aggregates of soluble elastin. The mechanism of this substrate specificity may be related to separate binding and catalytic sites on the collagen and elastin molecules. Highly purified enzyme from several different tissues utilizes both collagen and proelastin as substrates. The molecular weight of most species studied is 30,000 or a multiple thereof. Study of the activity in biological systems indicates that it is pituitary dependent, has a half-life of approximately 16 hours after a BAPN pulse, and may undergo increased synthesis or activation after restoration of copper. Lysyl oxidase deficiency is probably the principal defect in experimental lathyrism and in the aneurysm-prone mouse. It may contribute to the pathogenesis of the human diseases, X-linked cutis laxa, X-linked Ehlers-Danlos syndrome, and Menke's kinky hair syndrome. Increases in activity correlate with development of increased wound tensile strength in implanted sponges and connective tissue deposition in hepatic fibrosis.
Since collagen biosynthesis was last reviewed in the Journal in 1972, much new information has been gained about the relatively complex pathway by which it is synthesized. The authors consider this new information and some of its consequences in terms of the following questions: (1) What is the structural information in the collagen molecule, and how does it determine the structure of the collagen fibril? (2) What are the structure and function of the precursor form of collagen known as procollagen? (3) How is procollagen synthesized and used to assemble collagen fibrils? (4) How do defects in biosynthesis explain genetic diseases of collagen? (5) How is collagen synthesis regulated under normal conditions and in acquired diseases?
Nutritional copper deficiency effects marked changes in the crosslinking of collagen and elastin, presumably in relationship to copper's role as a cofactor for lysyl oxidase. Lysyl oxidase controls one of the initial steps in the crosslinking of elastin and collagen, i.e., the conversion of peptidyl lysine or hydroxylysine residues to peptidyl alpha-aminoadipic-delta-semialdehyde derivatives. Once lysine-derived aldehydic functions in collagen and elastin are formed, crosslinks occur via aldol and Schiff-base type condensations. A decrease in the degree of crosslinking results in changes in the biomechanical properties of both collagen- and elastin-rich tissues. Some of these changes are described with respect to chick bone and aorta. Likewise, penicillamine blocks crosslinking reactions. In this case, however, it is probably because of the formation of thiazolidine complexes between penicillamine aldehydic functions. The administration of penicillamine at different levels to young growing chicks allows the isolation of fibrous insoluble elastin varying in aldehyde content.
Collagen is a major constituent of skin, bone, tendon, and cartilage and is a vital component of the cardiovascular system. Not only is collagen an important protein because of its relative abundance, estimates indicate that it constitutes as much as 40% of the total body protein, but also it is the only protein in the body that has been clearly shown to undergo molecular changes during the aging process in man and animals, i. e., it “ages.” One of the outward manifestations of aging in collagen is the wrinkling of the skin which is inevitable in the elderly. Another, which is not so obvious but is of infinitely greater importance to man is the age-associated loss of elasticity in the cardiovascular system.
The lesions and locations of the spectrum of scleroderma related syndromes are characteristically varied in site, in intensity, and in their rate of progression. They all share an intense fibrotic reaction which is similar to wound healing but diffuse in extent, unregulated in its progression, and virtually impossible to reverse with the present armamentarium. This fibrosis is associated with prominent vascular and microvascular lesions, with distinctive autoimmune and immune aberrations, and a variety of cellular/inflammatory characteristics in selected anatomic sites which leads to a rich panoply of clinically diverse syndromes. Some headway has been made in the cellular and molecular understanding of human fibrosis, but much more detailed comprehension is needed before biologically targeted intervention will be predictable in the management and reversal of fibrosis in the diverse human conditions in which it now significantly disrupts function, including keloids, hepatic cirrhosis, pulmonary fibrosis, atherosclerosis, and, as emphasized in this brief review, scleroderma (systemic sclerosis).
The effects of various avocado oils on some liver characteristics were studied in growing rats. The rats were fed diets containing 10% (w/w) avocado oil for 4 wk. In comparison with rats fed refined oil obtained from cored fruit by centrifugal separation, rats fed unrefined avocado oil obtained by solvent extraction from the intact fruit, or refined avocado oil containing avocado-seed oil, showed significant growth inhibition, an increase in the amount of hepatic lipids (identified as steatosis by histopathological examination), and a decrease in levels of triglycerides in blood. Rats fed the refined oil containing unsaponifiable material prepared from unrefined oil from the intact fruit showed similar responses. Fatty livers were not induced by feeding rats unrefined avocado oil obtained from intact fruit by centrifugal separation, although a significant decrease in blood triglycerides was observed. There were no significant differences between groups in serum total protein, albumin or bilirubin content or in alanine aminotransferase activity. However, serum alkaline phosphatase activity was increased in rats fed the seed oil, the unrefined solvent-extracted oil from intact fruit, or the unsaponifiables, and aspartate aminotransferase activity was significantly increased in the group fed avocado-seed oil. These data suggest that consumption of avocado oil extracted from intact fruit may cause changes in liver metabolism.
Lysyl oxidase was purified to about 3,000- to 5,000-fold from epiphyseal cartilages of chick embryos. Purification was accomplished by sequential column chromatographies of collagen-sepharose, DEAE-Cellulose and Sephacryl S-200. The molecular weight of the most purified enzyme from 4 different isomers as determined by gel-filtration technique using Sephacryl S-200 column was 32,000 and the purified enzyme contained one copper atom per mole. When the enzyme (copper content: 1.12 g-atom per mole) was incubated with 1 X 10(-4)M cadmium, followed by gel-filtration, 0.12 g-atom of cadmium was incorporated into the enzyme per mole and consequently 0.23 g-atom of prosthetic copper was released from the enzyme (loss of 21%) with a substantial decrease of the enzyme activity by 22.8%, but 50% loss of copper caused by treatment with 1 X 10(-3)M cadmium did not further decrease the activity. When the enzyme was incubated with 1 X 10(-4)M zinc, 0.38 g-atom of zinc bound to the enzyme and 65% copper was lost, resulting in 34% loss of the activity. Loss of 84% copper (experiment with 1 X 10(-3)M zinc), however, led to 47% inhibition. These findings indicate the existence of metal-metal interaction in the enzyme that can significantly influence the activity, though inhibition of the enzyme was not strictly proportional to either the amount of copper released or the amount of cadmium or zinc bound to the enzyme.
A group of eight new long-chain aliphatic compounds recently isolated from the avocado and some derivatives thereof were tested for antibacterial activity on 13 different species of bacteria and a yeast. Some of these compounds inhibited the growth of microorganisms. 1,2,4-Trihydroxy-n-hepadeca-16-en was found to be the most active, inhibiting certain gram-positive bacteria at 4 mug/ml.
Longissimus dorsi muscles were removed from the carcasses of 60 Charolais-cross steers in order to examine the relationship between five feeding systems and collagen solubility values obtained by two different methods (warm and cold extractions). Steers were provided with either a 75% concentrate diet, 50% concentrate diet, corn silage diet, corn silage to 400 kg live weight followed by the 75% concentrate diet or alfalfa silage fed to 400 kg live weight followed by the 75% concentrate diet. Steers on the 75% concentrate diet throughout the feeding period required the least time on feed, had the lowest slaughter and carcass weights and produced meat with the highest warm collagen solubility values. Steers fed corn silage continuously needed the longest time on feed, had the lowest daily rates of gain and produced meat with the lowest warm collagen solubility values. Despite being on feed for a longer length of time, steers fed corn silage or alfalfa silage prior to finishing on the 75% concentrate diet produced meat with warm collagen solubility values similar to those continuously fed the 50% concentrate diet. Steers fed the 75% concentrate diet subsequent to forage feeding exhibited greater rates of gain before slaughter while those fed the 75% concentrate diet continuously showed a rapid decline in rate of gain with increasing body weight. Total collagen and cold collagen values were similar among feeding systems. These results indicated that plane of nutrition before slaughter and days on feed both exerted an influence on the properties of intramuscular collagen.
Increasing interest in the vascular features of scleroderma has led to the hypothesis that the blood vessel is the major target tissue and that the endothelial cell is the principal cell target. Useful observations stemming from the vascular hypothesis include the use of microvascular abnormalities in the early detection of the patient destined to develop classical scleroderma, the discovery of a serum protease selectively cytotoxic to endothelial cells, and the study of a serum mitogenic activity for fibroblasts in scleroderma patients. Immune events related to the vascular lesions are under active study but have not as yet provided a unique immunological lesion in scleroderma patients. The possibility that immunity to basement membrane (type IV) collagen may be selective for scleroderma patients deserves further study. Persistent immunity to endothelial basement membrane structures would provide a basis for continued endothelial injury. Techniques to quantify endothelial injury are useful to assess activity of the vascular lesions and to monitor therapies designed to block further vascular injury. The definition of pre-fibrotic vascular lesions may have future therapeutic and preventive implications for scleroderma.
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686
Since 1922 when Wu proposed the use of the Folin phenol reagent for
the measurement of proteins (l), a number of modified analytical pro-
cedures ut.ilizing this reagent have been reported for the determination
of proteins in serum (2-G), in antigen-antibody precipitates (7-9), and
in insulin (10).
Although the reagent would seem to be recommended by its great sen-
sitivity and the simplicity of procedure possible with its use, it has not
found great favor for general biochemical purposes.
In the belief that this reagent, nevertheless, has considerable merit for
certain application, but that its peculiarities and limitations need to be
understood for its fullest exploitation, it has been studied with regard t.o
effects of variations in pH, time of reaction, and concentration of react-
ants, permissible levels of reagents commonly used in handling proteins,
and interfering subst.ances. Procedures are described for measuring pro-
tein in solution or after precipitation wit,h acids or other agents, and for
the determination of as little as 0.2 y of protein.
Pharamacological biochemistry of connective tissues: I. Influence of lipidic plant-extracts on the evolution of the carrageenan-induced granuloma
- A M Robert
- M Miskulin
- G Godeau
Effect of vitamin B-6 deficiency on the crosslink formation of collagen
- K Fuji
- R Kajiwara
- H Kuroso
Biochemical pharmacology of connective tissues: II. Evaluation of enzymatic activities in carrageenan granulomas. Influence of lipidic plant-extracts
- A M Robert
- M Miskulin
- G Godeau
Biochemical pharmacology of connective tissues: III. Influence of lipidic extracts on the composition of carrageenan-granuloma
- A M Robert
- M Miskulin
- G Godeau
The avocado pear. The Biochemistry of Fruits and Their Products, A. C
- J B Biale
- R E Young