T Kobayashi's scientific contributionswhile working at Kochi Medical School (Kochi, Japan) and other institutions

Publications (28)

Publications citing this author (452)

    • B cells are more radiosensitive than T cells, and overall, their radiosensitivity, as measured by clonogenic assay, is similar to that of hematopoietic stem cells. Because human peripheral lymphocytes and lymphoma/leukemia cells of lymphoid tissue origin lack peroxidase activity, these cells are quite susceptible to oxidative stress such as that caused by ROS, including H2O2 [12,13]. When T cells are irradiated, H2O2 produced by ROS accumulates in the cytoplasm of lymphocytes and then moves into the lysosomes, where it causes lysosomal membrane dysfunction and ultimately apoptosis [14,15] (Figure 2).
    [Show abstract] [Hide abstract] ABSTRACT: Most radiation biologists/radiation oncologists have long accepted the concept that the biologic effects of radiation principally involve damage to deoxyribonucleic acid (DNA), which is the critical target, as described in "Radiobiology for the Radiologist", by E.J. Hall and A.J. Giaccia [1]. Although the concepts of direct and indirect effects of radiation are fully applicable to low-LET (linear energy transfer) radioresistant tumor cells/normal tissues such as osteosarcoma cells and chondrocytes, it is believed that radiation-associated damage to DNA does not play a major role in the mechanism of cell death in low-LET radiosensitive tumors/normal tissues such as malignant lymphoma cells and lymphocytes. Hall and Giaccia describe lymphocytes as very radiosensitive, based largely on apoptosis subsequent to irradiation. As described in this review, apoptosis of lymphocytes and lymphoma cells is actually induced by the "hydrogen peroxide (H₂O₂) effect", which I propose in this review article for the first time. The mechanism of lymphocyte death via the H₂O₂ effect represents an ideal model to develop the enhancement method of radiosensitivity for radiation therapy of malignant neoplasms. In terms of imitating the high radiosensitivity of lymphocytes, osteosarcoma cells (representative of low-LET radioresistant cells) might be the ideal model for indicating the conversion of cells from radioresistant to radiosensitive utilizing the H₂O₂ effect. External beam radiation such as X-rays and high-energy electrons for use in modern radiotherapy are generally produced using a linear accelerator. We theorized that when tumors are irradiated in the presence of H₂O₂, the activities of anti-oxidative enzymes such as peroxidases and catalase are blocked and oxygen molecules are produced at the same time via the H₂O₂ effect, resulting in oxidative damage to low-LET radioresistant tumor cells, thereby rendering them highly sensitive to irradiation. In this review, this potential paradigm shift in modern radiation biology/radiation oncology is discussed in detail in terms of overcoming drug/radiation resistance in radiation therapy and/or anti-cancer chemotherapy.
    Full-text · Article · Feb 2016
    • Previous TEM studies of lanceolate endings also failed to define the apical cones probably because of their resemblance to free nerve endings in thin tissue sections (Andres, 1966; Halata, 1993). It is worth mentioning thatFigure 6 of Seguchi et al. (1989) is an SEM presentation of some thread-like processes arising from pointed ends of lanceolate terminals in rat ordinary hairs, although no references were made concerning the structures. The two portions of the lanceolate endings observed in the present study differed markedly from each other in their relationships with the surrounding tissues (Fig. 7).
    [Show abstract] [Hide abstract] ABSTRACT: The longitudinal lanceolate endings are ubiquitous sensory terminals in the sinus and nonsinus hairs of mammals that form a palisade around the hair follicle. To analyze how the nerve endings detect hair movements, the present study re-examined their fine structure and relationships with surrounding connective tissue in rat vibrissae by using a combination of three methods: immunohistochemistry for S-100 protein, scanning electron microscopy of NaOH-macerated specimens, and transmission electron microscopy of serial sections. Observations showed the lanceolate endings to be represented by triplet units with a flattened axon terminal flanked on each side by a Schwann cell lamella, as reported previously. Two distinct parts were discriminated in the lanceolate ending: a principal portion in which the axon terminal protruded numerous fine fingers from between the Schwann cell coverings, and an apical cone that enclosed a large axon finger in an attenuated Schwann sheath. Long foot processes of Schwann cells fanned out distally from each apical cone. The principal portions of the lanceolate endings were firmly linked to the surrounding connective tissue by the narrow edges equipped with axon fingers, suggesting their continuous deformation by sustained hair deflections. In contrast, the apical cones were freely suspended in an amorphous matrix with only the end feet of the Schwann cell projections attached to rigid tissue elements. This part of the ending was proposed as a possible transducer site to generate rapidly adapting receptor potentials, both retreating and overshooting during the acceleration and deceleration phases of a given vibrissal movement.
    Full-text · Article · Nov 2000
    • Cryosections of 5 µm were cut on an HM 500 OM microtome cryostat (Microm Laborgerate GmbH, Walldorf, Germany) at 25 C and used for catalytic histochemistry. Sections were collected on poly--lysine-coated slides, air dried for 20 min and fixed using 0·5% glutaraldehyde in 0·1 M cacodylate buffer, pH 7·2, for 1 min at 4 C. Detection of Na + / K + ATPase was performed by the method of Kobayashi et al. (1987) modified by Zemanova and Gossrau (1994) which uses p-nitrophenyl phosphate as substrate and cerium ions for inorganic phosphate capture. For the visualization of cerium phosphate, 3,3-diaminobenzidine- H 2 O 2 -Ni-hexamonium sulphate was used.
    [Show abstract] [Hide abstract] ABSTRACT: We have previously shown that angiotensin II (Ang II) has a role at the level of the eel gill chloride cell regulating sodium balance, and therefore osmoregulation; the purpose of the present study was to extend these findings to another important osmoregulatory organ, the kidney. By catalytic histochemistry Na(+)/K(+)ATPase activity was found in both sea water (SW)- and freshwater (FW)-adapted eel kidney, particularly at the level of both proximal and distal tubules. Quantitation of tubular cell Na(+)/K(+)ATPase activity, by imaging, gave values in SW-adapted eels which were double those found in FW-adapted eels (Student's t-test: P<0.0001). This was due to a reduced number of positive tubules present in FW-adapted eels compared with SW-adapted eels. By conventional enzymatic assay, the Na(+)/K(+)ATPase activity in isolated tubular cells from SW-adapted eels showed values 1.85-fold higher those found in FW-adapted eels (Student's ttest: P<0.0001). Perfusion of kidney for 20 min with 100 nM Ang II provoked a significant increase (1.8-fold) in Na(+)/K(+)ATPase activity in FW, due to up-regulation of Na(+)/K(+)ATPase activity in a significantly larger number of tubules (Student's t-test: P<0.0001). The effect of 100 nM Ang II in SW-adapted kidneys was not significant. Stimulation with increasing Ang II concentrations was performed on isolated kidney tubule cells: Ang II provoked a dose-dependent stimulation of the Na(+)/K(+)ATPase activity in FW-adapted eels, reaching a maximum at 100 nM (1.82-fold stimulation), but no significant effect was found in SW-adapted eels (ANOVA: P<0.001 and P>0.05 respectively). Isolated tubule cells stimulated with 100 nM Ang II showed a significant generation of inositol trisphosphate (InsP(3)) and an increment in calcium release from intracellular stores. In conclusion, our results suggest that tubular Na(+)/K(+)ATPase is modulated by environmental salinity, and that Ang II has a role in regulating its activity in FW-adapted eels, probably through an InsP(3)-dependent mechanism.
    Full-text · Article · Apr 2000
    • In cytochemical preparations carried out with neutrophils in suspension, intracellular sites of ROS production have been observed (Kobayashi et al. 1998; Brown et al. 2003 ). We have shown, as have others, that the intracellular trafficking of membrane-bounded compartments in activated neutrophils can be very dramatic and complex (Kobayashi and Robinson, 1991; Robinson et al. 1999). This point is illustrated further herein (seeFig.
    [Show abstract] [Hide abstract] ABSTRACT: Phagocytic leukocytes consume oxygen and generate reactive oxygen species in response to appropriate stimuli. The phagocyte NADPH oxidase, a multiprotein complex, existing in the dissociated state in resting cells becomes assembled into the functional oxidase complex upon stimulation and then generates superoxide anions. Biochemical aspects of the NADPH oxidase are briefly discussed in this review; however, the major focus relates to the contributions of various modes of microscopy to our understanding of the NADPH oxidase and the cell biology of phagocytic leukocytes.
    Article · Aug 2008
    • In fact, the cardiomyocytes grown for 48 hrs in the absence of RLX mostly showed an organellular complement typical of immature cells, containing free polyribosomes , some dilated rough endoplasmic reticulum (RER) cisternae, diffuse cytoskeletal components, sparse glycogenic fields and small, round-shaped mitochondria (Fig. 4A). Instead, at the same end-point, the RLX-treated cardiomyocytes mostly displayed muscle cell features, with numerous leptomeres, that is cross-banded structures composed of periodically arranged electron-dense bands bridged by 5-nm-thick filaments [33], and abundant mitochondria with packed cristae and condensed matrix (Fig. 4B). Cells at a more advanced stage of striated muscle maturation, containing myofibrillar structures, rodshaped mitochondria with electron-dense matrix granules and intercellular junctions featuring rudimentary intercalated discs were seldom encountered in the RLX-treated cultures, but not in the control ones (Fig. 4CTable 2 Membrane capacitance (Cm) and activation Boltzmann parameters of INa, ICa,T, ICa,L and If currents in the cardiomyocytes grown for 24 and 48 hrs in the absence or the presence of RLX Ip: data of the peak current at the voltage eliciting the maximal current; Ito: data at 50 mV; IK1: data at 120 mV; If: data at 150 mV; ICa,T evaluated in the presence of nifedipine, and ICa,L evaluated after detracting ICa,T from the total Ca 2 current (ICa,tot, see alsoFig.
    [Show abstract] [Hide abstract] ABSTRACT: The demonstration that the adult heart contains myocardial progenitor cells which can be recruited in an attempt to replace the injured myocardium has sparkled interest towards novel molecules capable of improving the differentiation of these cells. In this context, the peptide hormone relaxin (RLX), recently validated as a cardiovascular hormone, is a promising candidate. This study was designed to test the hypothesis that RLX may promote the growth and maturation of mouse neonatal immature cardiomyocytes in primary culture. The cultures were studied at 2, 12, 24 and 48 hrs after the addition of human recombinant H2 RLX (100 ng/ml), the main circulating form of the hormone, or plain medium by combining molecular biology, morphology and electrophysiology. RLX modulated cell proliferation, promoting it at 2 and 12 hrs and inhibiting it at 24 hrs; RLX also induced the expression of both cardiac-specific transcription factors (GATA-4 and Nkx2-5) and cardiac-specific structural genes (connexin 43, troponin T and HCN4 ion channel) at both the mRNA and protein level. Consistently, RLX induced the appearance of ultrastructural and electrophysiological signs of functionally competent, mature cardiomyocytes. In conclusion, this study provides novel circumstantial evidence that RLX specifically acts on immature cardiomyocytes by promoting their proliferation and maturation. This notion suggests that RLX, for which the heart is both a source and target organ, may be an endogenous regulator of cardiac morphogenesis during pre-natal life and could participate in heart regeneration and repair, both as endogenous myocardium-derived factor and exogenous cardiotropic drug, during adult life.
    Full-text · Article · May 2011
    • Although several studies have suggested that the functional oxidase complex at the plasma membranes is associated with the cytoskeleton (Nauseef et al., 1991; Dusi et al., 1996; Allen et al., 1999), the present findings suggest that assembly of the NADPH oxidase complex and its association with cPLA 2 stimulated by these agonists are independent of an intact cytoskeleton in nonadherent neutrophils. Furthermore, in accordance with these results superoxide generation and translocation of the cytosolic oxidase components to membranes of nonadherent neutrophils pretreated with cytochalasin b was increased when stimulated with fMLP or OZ but was not affected when stimulated with PMA (unpublished data; Dusi et al., 1996; Yan and Novak, 1999; Jiang et al., 2000).
    [Show abstract] [Hide abstract] ABSTRACT: Cytosolic phospholipase A2 (cPLA2)-generated arachidonic acid (AA) has been shown to be an essential requirement for the activation of NADPH oxidase, in addition to its being the major enzyme involved in the formation of eicosanoid at the nuclear membranes. The mechanism by which cPLA2 regulates NADPH oxidase activity is not known, particularly since the NADPH oxidase complex is localized in the plasma membranes of stimulated cells. The present study is the first to demonstrate that upon stimulation cPLA2 is transiently recruited to the plasma membranes by a functional NADPH oxidase in neutrophils and in granulocyte-like PLB-985 cells. Coimmunoprecipitation experiments and double labeling immunofluorescence analysis demonstrated the unique colocalization of cPLA2 and the NADPH oxidase in plasma membranes of stimulated cells, in correlation with the kinetic burst of superoxide production. A specific affinity in vitro binding was detected between GST-p47phox or GST-p67phox and cPLA2 in lysates of stimulated cells. The association between these two enzymes provides the molecular basis for AA released by cPLA2 to activate the assembled NADPH oxidase. The ability of cPLA2 to regulate two different functions in the same cells (superoxide generation and eicosanoid production) is achieved by a novel dual subcellular localization of cPLA2 to different targets.
    Full-text · Article · Sep 2003
    • Both lactoferrin and NGAL are localized in the specific granules [5] and the colocalization score for these two markers in resting cells (Fig. 3A ) was 1.6 which is within the range calculated above (Fig. 2C). Heterotypic granule fusion between specific granules and azurophil granules has previously been observed microscopically after e.g., PMA stimulation [16,27,28]. In addition, such fusion has been indirectly concluded to take place based on the fact that PMA-stimulation gives rise to intracellular MPO-processing of ROS originating from the NADPH-oxidase [1,171819.
    [Show abstract] [Hide abstract] ABSTRACT: Fig. 1. Gating strategy. The gating was done according to the colocalization wizard in the IDEAS software. Only cells in focus (A) and single cells (B) were included. Neutrophils were gated based on their positivity of DAPI and being low in side scatter (SSC), excluding anuclear debris and eosinophils (high in side scatter due to inherent aoutofluorescence) (C). Finally, only neutrophils with strong positive staining for both markers were selected (D). Brightfield (BF) images and indicated fluorescently labeled markers are depicted.
    Full-text · Article · Mar 2016
    • In the liver, extracelluar nucleotides regulate diverse biological functions and are important in the regulation of liver metabolism , hepatic blood flow, and bile secretion (reviewed in Schwiebert and Zsembery, 2003). It has been suggested that canalicular ecto-ATPase is involved in the efflux of bile acid in the development of the rat liver (Okada et al., 1999). Complement factor B (Bf; XL083h15) is also exclusively expressed in the liver (Fig. 6; Table 2E).
    [Show abstract] [Hide abstract] ABSTRACT: The endoderm is classically defined as the innermost layer of three Metazoan germ layers. During organogenesis, the endoderm gives rise to the digestive and respiratory tracts as well as associated organs such as the liver, pancreas, and lung. At present, however, how the endoderm forms the variety of cell types of digestive and respiratory tracts as well as the budding organs is not well understood. In order to investigate the molecular basis and mechanism of organogenesis and to identify the endodermal organ-related marker genes, we carried out microarray analysis using Xenopus cDNA chips. To achieve this goal, we isolated the Xenopus gut endoderm from three different stages of Xenopus organogenesis, and separated each stage of gut endoderm into anterior and posterior regions. Competitive hybridization of cDNA between the anterior and posterior endoderm regions, to screen genes that specifically expressed in the major organs, revealed 915 candidates. We then selected 104 clones for in situ hybridization analysis. Here, we report the identification and expression patterns of the 104 Xenopus endodermal genes, which would serve as useful markers for studying endodermal organ development.
    Full-text · Article · Jun 2007
    • As a corollary, cells undergoing apoptosis resulting from abortive cell cycle are actively cycling. In contrast, when cells enter factor withdrawal–induced apoptosis, their growth is arrested (12, 18, 19). This is best represented by IL-3-dependent 32D cells.
    [Show abstract] [Hide abstract] ABSTRACT: Apoptosis plays a critical role in cellular homeostasis during development, immune responses, and tumorigenesis. Recent studies have identified a number of genes that control this process. We report here our identification of a novel cell survival-related gene (SRG) from a human expression cDNA library by functional cloning. SRG shows no significant nucleotide sequence homology to any known genes in the Genbank. Our fluorescence in situ hybridization analysis has estimated that SRG is located at 1p36, agreeing with the location at 1p36.22 in the human genome sequence. SRG encodes a putative protein of 172 amino acids, which is mainly located in the perinuclear region. Northern blotting analysis indicates that SRG is highly expressed in many human cancer cell lines although it is low in most tissues except liver and placenta. To investigate the function of SRG in apoptosis, we transfected SRG cDNA into BAF/BO3 and B16/F0 cells and induced apoptosis by cytokine/serum deprivation. We found that SRG-transfected cells are resistant to apoptosis induced by cytokine/serum deprivation. In addition, mice bearing SRG-transfected melanoma had more tumor formation and larger tumor growth. Melanoma transfected with antisense SRG showed significantly less tumor formation and smaller tumor growth. Interestingly, mouse SRG gene was also identified on chromosome 4 and blocking SRG expression with small interfering RNA promoted serum deprivation-induced apoptosis of NIH3T3 cells. Our results show that SRG is a novel cell survival gene that critically controls apoptosis and tumor formation.
    Full-text · Article · Jan 2006
    • Além de permitir observar a presença de grânulos de secreção no interior dos ductos e dos ácinos propriamente ditos. Observações semelhantes têm sido realizadas por Watanabe et al. (1996), D' Avola et al. (2006) e Pícoli et al. (2011).
    [Show abstract] [Hide abstract] ABSTRACT: Resumo: Estudos acerca da morfologia de animais silvestres servem de subsídio para trabalhos de manejo e preservação de diferentes espécies, pois fornecem informações para a tomada de medidas que auxiliem na manutenção destes em cativeiro, na preservação em habitat natural ou mesmo para ações voltadas a reintrodução ao habitat de origem. Estudos referentes à morfologia de cutias abordam os diversos sistemas, mas nenhum faz referência à arquitetura ou estrutura de suas glândulas salivares. Assim este trabalho objetivou descrever macro e microscopicamente as glândulas salivares maiores de cutias. Foram utilizados dez animais adultos para o desenvolvimento de metodologias relativas à macroscopia propriamente dita das glândulas, microscopia de luz, microscopia eletrônica de transmissão e microscopia eletrônica de varredura. Foram identificadas quatro glândulas salivares maiores nos animais estudados, denominadas parótida, mandibular, zigomática e sublingual. As glândulas apresentaram-se como sendo do tipo tubuloacinares e contendo em seu parênquima ductos dos mais variados tamanhos. Com exceção da glândula parótida, que era estritamente serosa, as demais eram mistas. Da mesma forma, apenas a glândula mandibular foi identificada a presença de ducto do tipo granuloso. Apresentando as cutias os quatro pares de glândulas salivares maiores, estes animais podem servir de modelo para os estudos acerca das mudanças anatômicas sofridas pelos roedores para se adaptar aos diversos habitat do planeta.
    Full-text · Article · Dec 2016
    • Animal exposure to inappropriate environmental conditions can disturb normal cellular functions by opening the way for a series of oxidative chain reactions that affect cellular integrity (Lykkesfeldt and Svendsen 2007). Reactive oxygen species are normally generated during cellular metabolism and are essential for the regulation of cellular activity (Kobayashi et al. 2001) by promoting the phagocytosis of pathogenic organisms and acting as a key signal in the physiological processes of oocyte maturation and fertilisation during pregnancy and birth (Kirschvink et al. 2008). Pregnancy is a physiological state accompanied by a high-energy demand of many bodily functions and an increased oxygen requirement.
    [Show abstract] [Hide abstract] ABSTRACT: Two doses of natural extract from Lippia citriodora (titrated in verbascoside) were assessed in New Zealand White rabbit does evaluating selected reproductive, productive and plasma biochemical parameters. After 1 week of adaptation period, the trial on 45 rabbit does for three consecutive reproductive cycles was conducted; does were divided into three groups of 15 animals each, homogenous by age (1 year ` 2 weeks), bodyweight (4.77 ` 0.21 kg) and parity (2 ` 1). A control group (CON) did not receive the dietary supplement in the feed and the other two groups received 1 g of natural extract supplement in the feed (5 mg verbascoside/kg feed; LNE) and 2 g of natural extract (10 mg verbascoside/kg feed; HNE). The use of a dietary NE supplement improved kit bodyweight at weaning (934 vs 1104 g; P < 0.001), and average daily weight gain from birth to weaning (24.7 vs 29.7 g/day; P < 0.001), with no NE dose effect. In the LNE and HNE groups serum triglycerides, total cholesterol, low density lipoprotein cholesterol, bilirubin, and activities of alkaline phosphatase, alanine aminotransferase (P < 0.05) and aspartate aminotransferase (P < 0.01) decreased and high density lipoprotein cholesterol (P < 0.01) increased, according to the cycle effect. The dietary supplement also improved blood oxidative status markers in the experimental groups due to an increase in the concentrations of plasma vitamin A and E (P < 0.01) and a decrease in plasma reactive oxygen metabolites and thiobarbituric acid reactive substances values (P < 0.01). In conclusion, the dietary Lippia NE supplement improved selected productive and reproductive parameters and the animal welfare of does, expressed by a general improvement of blood profile, with no effect of the dose.
    Full-text · Article · Jan 2017
    • First reports of the effect of adenosine in the lower urinary tract suggested that it reduces the tone and spontaneous activity of the guinea-pig urinary bladder[30,34]. ATP release from both neuronal and non-neuronal cells (e.g., urothelial cells, interstitial cells, fibroblast-like cells, smooth muscle fibers) and its extracellular metabolism into adenosine has been observed in the urinary bladder of rodents[35][36][37]. Roughly 50 % of the extracellular adenosine results from the breakdown of ATP[38]which is currently regarded to be the most important route of generating extracellular adenosine[39].
    [Show abstract] [Hide abstract] ABSTRACT: This study was designed to investigate whether reduced adenosine formation linked to deficits in extracellular ATP hydrolysis by NTPDases contributes to detrusor neuromodulatory changes associated with bladder outlet obstruction in men with benign prostatic hyperplasia (BPH). The kinetics of ATP catabolism and adenosine formation as well as the role of P1 receptor agonists on muscle tension and nerve-evoked [3H]ACh release were evaluated in mucosal-denuded detrusor strips from BPH patients (n = 31) and control organ donors (n = 23). The neurogenic release of ATP and [3H]ACh was higher (P < 0.05) in detrusor strips from BPH patients. The extracellular hydrolysis of ATP and, subsequent, adenosine formation was slower (t 1/2 73 vs. 36 min, P < 0.05) in BPH detrusor strips. The A1 receptor-mediated inhibition of evoked [3H]ACh release by adenosine (100 μM), NECA (1 μM), and R-PIA (0.3 μM) was enhanced in BPH bladders. Relaxation of detrusor contractions induced by acetylcholine required 30-fold higher concentrations of adenosine. Despite VAChT-positive cholinergic nerves exhibiting higher A1 immunoreactivity in BPH bladders, the endogenous adenosine tonus revealed by adenosine deaminase is missing. Restoration of A1 inhibition was achieved by favoring (1) ATP hydrolysis with apyrase (2 U mL−1) or (2) extracellular adenosine accumulation with dipyridamole or EHNA, as these drugs inhibit adenosine uptake and deamination, respectively. In conclusion, reduced ATP hydrolysis leads to deficient adenosine formation and A1 receptor-mediated inhibition of cholinergic nerve activity in the obstructed human bladder. Thus, we propose that pharmacological manipulation of endogenous adenosine levels and/or A1 receptor activation might be useful to control bladder overactivity in BPH patients.
    Full-text · Article · Nov 2015
    • Whereas the endolymph compartment has high K 1 and low Na 1 that is similar to intracellular environment of the body (Anniko and Wroblewski, 1986). The high K 1 concentration is maintained by the activity of Na 1 =K 1 -ATPase present on the marginal cells of the stria vascularis (Nishiyama et al., 1994) (Fig. 1). The scala media contains the " organ of Corti " which is present on top of the basilar membrane .
    [Show abstract] [Hide abstract] ABSTRACT: Mechanosensory transduction underlies the perception of touch, sound and acceleration. The mechanical signals exist in the environment are re-sensed by the specialized mechanosensory cells, which convert the external forces into the electrical signals. Hearing is a magnificent example that relies on the mechanotransduction mediated by the auditory cells, for example the inner-ear hair cells in vertebrates and the Johnston's organ in fly. Previous studies have shown the fundamental physiological processes in the fly and vertebrate auditory organs are similar, suggesting that there might be a set of similar molecules underlying these processes. The molecular studies of the fly Johnston's organ have been shown to be remarkably successful in discovering the developmental and functional genes that provided further implications in vertebrates. Several evolutionarily conserved molecules and signaling pathways have been shown to govern the development of the auditory organs in both vertebrates and invertebrates. The current review describes the similarities and differences between the vertebrate and fly auditory organs at developmental, structural, molecular and transportation levels.
    Full-text · Article · Aug 2014
    • This regulatory mechanism of the cytoskeleton, however, remains to be fully understood in rat neutrophils and further studies need to be performed to elucidate the synergistic response of fMLP and CB. Previous studies in our laboratory on alkaline phosphatase (ALPase) activity in neutrophils have shown that ALPase is confined to a unique population of cytoplasmic compartments distinct from the azurophil and specific granules of neutrophils in human (Kobayashi and Robinson, 1991) and rat (Jiang et al., 1996Jiang et al., , 1998). This activity can be upregulated with PMA resulting in a redistribution of ALPase structures and exocytosis to the plasma membrane .
    [Show abstract] [Hide abstract] ABSTRACT: Superoxide anion production in neutrophils plays an important role in the microbicidal defense system in the body. In this study, isolated rat neutrophils were stimulated experimentally and examined by electron microscopy to determine the site of superoxide production and its subsequent translocation during different cell stimulation time periods. Blood and peritoneal neutrophils were incubated for periods of 5, 10, and 15 min with phorbol 12-myristate 13-acetate (PMA), N-formyl-Met-Leu-Phe (fMLP), and combinations of PMA and cytochalasin B (CB) and fMLP and CB. Ultracytochemical detection of O2− was performed with the 3,3′-diaminobenzidine-manganese (DAB/Mn) cytochemical method and cationized ferritin (CF) particles were added to stimulation media to monitor endocytotic events that occurred during neutrophil stimulation. Unstimulated neutrophils were devoid of O2− activity in cytoplasmic granules and at the plasma membrane surface. After 5 min stimulations with PMA, PMA + CB, or fMLP + CB, electron-dense DAB/Mn reaction product was detected in small, centrally located tubular compartments within the neutrophils. CF particles which were added to the stimulation media became internalized in endocytotic vesicles after 5 min stimulation; these vesicles were devoid of O2− activity. At 10 min stimulation with PMA, O2−-positive granules subsequently fused with each other and translocated to sub-plasma membrane regions where they either contacted the plasma membrane or fused with CF-containing endocytotic vesicles. Little reaction product was observed on the surface of the neutrophils. Spectrophotometric comparison of the stimulatory effects of PMA, fMLP, and fMLP + CB revealed different rates and yields of O2− production. Results from this study suggest that the O2−-producing sites of rat neutrophils originate intracellularly and translocate to the plasma membrane surface following stimulation with PMA, PMA + CB, and fMLP + CB, but not with fMLP or CB alone. Furthermore, these compartments appear to possess the ability to fuse with endocytotic vesicles, a process that may be linked to intracellular microbicidal activity in circulating and tissue neutrophils. Anat Rec 258:156–165, 2000. © 2000 Wiley-Liss, Inc.
    Full-text · Article · Feb 2000