Miguel Alcaraz

Universidad de Murcia, Murcia, Murcia, Spain

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Publications (8)14.71 Total impact

  • Article: Increased transcutaneous oxygen pressure is an indicator of revascularization after peripheral transluminal angioplasty.
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    ABSTRACT: In recent years, the use of peripheral transluminal angioplasty (PTA) procedures for revascularization of an ischemic limb has increased. Evaluation of reperfusion has been carried out by Doppler scan; however, a successful PTA does not necessarily result in improved oxygen delivery to the distal parts of the limb. To evaluate the efficacy of the revascularization in diabetic patients with critical limb ischemia after treatment with PTA by comparing transcutaneous oxygen tension (TcpO₂) with the ankle-brachial index (ABI) post PTA. This prospective study included 151 consecutive diabetic patients. We evaluated the posterior tibial and dorsalis pedis Doppler, ABI, TcpO₂, and duplex scan results. If two of these four examinations were abnormal, arteriography was carried out and PTA was performed concomitantly. At least 64 patients were considered suitable candidates for PTA. The ABI increased from 0.67±0.25 to 0.84±0.25 following PTA (P<0.001). TcpO₂ increased from 27.20±11.10 mm Hg to 40±12.10 mm Hg after PTA (P<0.001). While the TcpO₂ could be measured in all patients, the ABI was not measurable in 25.37% pretreatment and in 17.91% post treatment. Statistical analysis revealed a scant correlation between the techniques used: TcpO₂ and ABI (P=0.20). Our study confirms that the increase in TcpO₂ in diabetic patients following PTA points to the physiologic significance of microvascular revascularization achieved in the treated limb and serves to assess functional improvement in tissue oxygenation obtained by PTA. The use of TcpO₂ may represent an alternative to traditional assessment of peripheral transluminal angioplasty results.
    Acta Radiologica 11/2010; 51(9):990-3. · 1.37 Impact Factor
  • Article: The effects of radiofrequency on skin: experimental study.
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    ABSTRACT: Radiofrequency represents the most recent skin-rejuvenation treatment. The aim of this study was to study the changes in tissues and cells, as well as in the thickness and structure of the skin of guinea pigs following several sessions of radiofrequency. Six sessions (1 session/week) of radiofrequency (Thermafine Lift device, Grupo Soliláser, S.L., Girona, Spain) were applied to the skin of guinea pigs. Biopsies were taken following each session and 2 months following the last application. The resultant samples were included in paraffin via the usual method, sectioned at 5 microm and stained with Haematoxylin-Eosin, Alcian blue, Toluidine blue, van Gieson's and Verhoeff's stains. These techniques were used in order to observe possible changes in the thickness and structures of the skin: mucopolysaccharides and collagen and elastic fibres. The most relevant changes were found in the papillary dermis which underwent an expansion due to oedema and vascular congestion (first half of the experiment), followed by an increase in cellularity and the accumulation of intercellular substance. An increase in collagen, elastic fibres and mucopolysaccharides was observed. The Thermafine Lift device caused no significant macroscopic or microscopic alterations in the skin of guinea pigs, yet increased both the thickness, as well as the mucopolysaccharide, collagen and elastic-fibre content.
    Lasers in Surgery and Medicine 03/2008; 40(2):76-82. · 2.75 Impact Factor
  • Article: The effects of radiofrequency on skin: Experimental study
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    ABSTRACT: Background and Objective Radiofrequency represents the most recent skin-rejuvenation treatment. The aim of this study was to study the changes in tissues and cells, as well as in the thickness and structure of the skin of guinea pigs following several sessions of radiofrequency.Materials and Methods Six sessions (1 session/week) of radiofrequency (Thermafine Lift device, Grupo Soliláser, S.L., Girona, Spain) were applied to the skin of guinea pigs. Biopsies were taken following each session and 2 months following the last application. The resultant samples were included in paraffin via the usual method, sectioned at 5 µm and stained with Haematoxylin-Eosin, Alcian blue, Toluidine blue, van Gieson's and Verhoeff's stains. These techniques were used in order to observe possible changes in the thickness and structures of the skin: mucopolysaccharides and collagen and elastic fibres.ResultsThe most relevant changes were found in the papillary dermis which underwent an expansion due to oedema and vascular congestion (first half of the experiment), followed by an increase in cellularity and the accumulation of intercellular substance. An increase in collagen, elastic fibres and mucopolysaccharides was observed.Conclusion The Thermafine Lift device caused no significant macroscopic or microscopic alterations in the skin of guinea pigs, yet increased both the thickness, as well as the mucopolysaccharide, collagen and elastic-fibre content. Lesers Surg. Med. 40:76–82, 2008. © 2008 Wiley-Liss, Inc.
    Lasers in Surgery and Medicine 01/2008; 40(2):76 - 82. · 2.75 Impact Factor
  • Article: Biological dosimetry and Bayesian analysis of chromosomal damage in thyroid cancer patients.
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    ABSTRACT: Chromosomal damage was investigated in lymphocytes of thyroid cancer patients after radioiodine treatment. An assay on micronuclei (MN) in binucleated cells was performed in blood samples of 25 patients 3 d after (131)I (3.7 GBq) was given. Statistical analysis does not show overdispersion of the MN distribution, thus considering the exposure to blood as being homogeneous (p < 0.05). A dose-protraction factor (G) of 0.1 was considered into the calculation of the blood dose to take into account the effect of the duration of exposure. The total MN count is a sum of the background distribution and the Poisson distribution induced by radiation exposure. A Bayesian approach was used to avoid inconsistencies when the total count was close to or lower than the background level. Estimated blood dose after 3 d of exposure was 0.73 Gy (0.197 mGy/MBq). The usefulness of the Bayesian method in analysing chromosomal damage when the count is low has been determined.
    Radiation Protection Dosimetry 10/2007; 129(4):372-80. · 0.82 Impact Factor
  • Article: Experimental model of pulmonary metastasis treatment with IFNalpha.
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    ABSTRACT: Melanoma shows the high rates of mortality, preferentially by metastasis, and the failure of chemotherapy. We inoculated 30 B16F10 Swiss mice with 5 x 10(5) melanocytes. The mice were then inoculated with 150,000; 300,000; 600,000 and 1,200,000 IU/mouse of interferon alpha. A count of the metastatic nodules of the lung surface and the microscopic study were made by image analysis on five histological sections, calculating the implantation percentage and tumoral growth and invasion index. Treatment with the three highest doses of interferon alpha resulted in a dose-dependent reduction of the number of metastatic nodules and invaded area. A correlation existing between the parameters studied and the different antitumoral effects observed.
    Cancer Letters 08/2005; 225(1):75-83. · 4.24 Impact Factor
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    Article: Cytotoxicity and antiproliferative activities of several phenolic compounds against three melanocytes cell lines: relationship between structure and activity.
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    ABSTRACT: Polyphenolic compounds are widely distributed in the vegetable kingdom and are therefore consumed regularly in the human diet. Epidemiological studies suggest that foods rich in polyphenolic compounds contribute to reducing the risk of cancer. The purpose of our work is to: 1) study the possible cytotoxicity and antiproliferative effects of 13 polyphenolic compounds on 3 cell lines of melanocytes, 2 of melanoma (B16F10 and SK-MEL-1), and 1 of nontransformed melanocytes (Melan-a); and 2) identify the possible relationship between the chemical structure of the tested compounds and their effect on cellular viability. The said polyphenolic compounds corresponded to 8 flavonoids with varying hydroxyl and methoxyl substituents, related structurally through the oxidation state of their flavonoid skeleton, a catechin polymer and 4 phenolic acids. The cytotoxic activity of all the studied compounds was modest or not apparent. The flavonoids luteolin, tangeretin, baicalein, quercetin, and myricetin, and gallic acid showed antiproliferative effects on the tested lines. Our results suggest that a correlation exists between the structural oxidation state and the position, number, and nature of substituents of the polyphenolic compounds studied and their antiproliferative effects.
    Nutrition and Cancer 02/2004; 49(2):191-9. · 2.78 Impact Factor
  • Article: Centropages behaviour: Swimming and vertical migration
    Miguel Alcaraz, Enric Saiz, Albert Calbet
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    ABSTRACT: The evolutionary success of any species living in a variable environment depends on its capacity to enhance the probability of finding food and mates, and escaping predators. In the case of copepods of the genus Centropages, as in all planktonic copepods, their swimming behaviour is closely tied to these vital aspects, and shows a high degree of plasticity and adaptive capacity. Swimming mechanisms of Centropages change radically during development, mainly in the transition between naupliar stages to the 1st copepodite; nauplii do not produce feeding currents, whereas copepodites do. Adults and late developmental stages of C. typicus, C. hamatus and C. velificatus spend most of the time in slow swimming and resting breaks, with occasional and brief fast swimming (escape reactions) and grooming events. Slow swimming is closely related to the creation of feeding currents, and results from the beating of the cephalic appendages in a “fling and clap” manner. The proportion of time allocated to the different swimming activities depends on sensory cues like type and concentration of food, presence of potential mates, light intensity, hydrodynamic flow, etc.The responses of Centropages to changes in flow velocity fluctuations (small-scale turbulence) are similar to the escape responses (fast swimming) triggered by the presence of potential predators. Centropages generally have standard nocturnal vertical migration patterns involving considerable vertical displacements. This behaviour is closely related to the narrow spectral sensitivity and the low intensity threshold of the genus, and has important consequences for the active vertical transport of matter and energy.The variety of responses of Centropages to environmental changes, and in general all the aspects related to its swimming behaviour seem to be controlled by the trade-off between energetic gains (food intake), losses (swimming energy expenditure), and predation risk. Behavioural plasticity and adaptation appear to be the most relevant characteristics for the success of the genus in a wide range of marine environments.
    Progress In Oceanography.
  • Article: Pigment gut contents of copepods and deep phytoplankton maximum in the Western Mediterranean
    Enric Saiz, Miguel Alcaraz
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    ABSTRACT: The feeding activity of Centropages typicus in the Western Mediterranean was evaluated during the summer stratification period, when a deep phytoplankton and chlorophyll maximum (DCM) develops. The lack of significant day-night differences in gut contents suggests continuous phytoplankton ingestion, despite nictemeral migration of this species. Copepods captured in the DCM had greater phytoplankton gut contents, both in nocturnal and diurnal samples. The observed pattern of phytoplankton ingestion and vertical migration implies copepod-mediated upward transport of nutrients, which might contribute to the maintenance of primary production in the photic layers.