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Biomedical subjects

S Kato

Publications and source records attributed to S Kato.

At least 1,063 records · Page 59Linked to original sources
PubMed1992

Expression of stress-response (heat-shock) protein 27 in human brain tumors: an immunohistochemical study.

This report concerns the expression of the low molecular weight stress-response (heat-shock) protein 27 (srp 27) in a variety of human brain tumors. Immunohistochemical techniques were used; cells of the breast cancer line MCF7 served as positive controls. The reaction product was found exclusively in the cytoplasm. Srp 27 was detected in 5/5 breast tumor metastases to the brain and in 5/21 meningiomas. The protein was also detected in 5/11 glioblastomas and 2/5 pituitary adenomas. By comparison, positive staining was observed in only 1/15 astrocytomas and 1/7 medulloblastoma and no reaction was seen with the oligodendrogliomas, schwannomas and gangliogliomas tested. These observations demonstrate that srp 27 is expressed by certain primary intracranial tumors.

Adenoma↗
PubMed1992

Effect of hyperosmolality on alkaline phosphatase and stress-response protein 27 of MCF-7 breast cancer cells.

MCF-7, a continuous cell line derived from a human breast carcinoma, exhibits very low alkaline phosphatase (ALP) activity. The enzyme is heat-stable and is inhibited by L-phenylalanine and L-phenylalanylglycylglycine, but not by L-homoarginine, 1-bromotetramisole, or levamisole. These data indicate that MCF-7 produces term-placental ALP, the oncodevelopmental enzyme form inappropriately expressed by a variety of human tumors. In contrast to human cancer cells that produce this enzyme monophenotypically, ALP activity of MCF-7 cells is not significantly increased by glucocorticoids or sodium butyrate. By comparison, exposure to hyperosmolality causes a striking increase in enzyme activity. Cycloheximide blocks this effect. The results obtained with cell-free assays were confirmed by cytochemical and immunocytochemical assays on whole cells. Because some of the agents tested in the enzyme modulation experiments affect cell proliferation, their possible effect on two stress-response proteins (srp 27 and srp 72) was also examined; specific immunocytochemical assays were used. These tests revealed that neither protein is affected by glucocorticoids; that sodium butyrate has no effect on srp 27, but alters the intracellular distribution of srp 72; and that hyperosmolality, while not significantly affecting srp 72, causes an increase in srp 27.

Alkaline Phosphatase↗
PubMed1992

Gastrointestinal endoscopy in Henoch-Schönlein purpura.

Gastrointestinal (GI) endoscopy was performed in seven patients with Henoch-Schönlein purpura (HSP). In two patients there were no cutaneous lesions at the time of endoscopy, but inflammation of the duodenum, especially of the second part, led to suspicion of the disease. Upper GI endoscopy showed abnormalities in six of seven cases, and sigmoidoscopy in one of four cases. The changes were more marked in the second part of the duodenum rather than in the bulb or the stomach. The endoscopic findings included redness, swelling, petechiae or haemorrhage, erosions and ulceration of the mucosa. Histology of the mucosal biopsy specimens revealed non-specific inflammation with positive staining for IgA in the capillaries, but failed to show vasculitis. Upper GI endoscopy, including study of IgA, can be useful in the diagnosis of HSP. Colonoscopy is less helpful, especially if limited to the sigmoid colon.

Adolescent↗
PubMed1992

Glucagon, insulin and somatostatin secretion in response to sympathetic neural activation in streptozotocin-induced diabetic rats. A study with the isolated perfused rat pancreas in vitro.

Changes in glucagon, insulin and somatostatin secretion induced by electrical splanchnic nerve stimulation were examined in rats treated with streptozotocin as neonates and as adults. In order to study the direct neural effects we used the isolated perfused rat pancreas with intact left splanchnic nerve in vitro. In normal rats splanchnic nerve stimulation causes significant decreases in insulin (30-40%) and somatostatin (30-50%) secretion at both 16.7 mmol/l and 1 mmol/l glucose concentrations. In the neonatal streptozotocin-diabetic rat splanchnic nerve stimulation at 16.7 mmol/l glucose decreased insulin secretion (14%) further than in the control rats (30%), however, somatostatin secretion did not decrease to the same extent. Similar results were also observed at the low (1 mmol/l) glucose concentration. On the other hand, percent decreases of insulin and somatostatin secretion induced by splanchnic nerve stimulation in the streptozocin-diabetic rats were similar to the values observed in the normal control rats. The glucagon secretion in response to splanchnic nerve stimulation at 16.7 mmol/l glucose from pancreatic Alpha cells in both types of induced diabetes is exaggerated, and the degree of exaggeration seems to parallel the severity of the hyperglycaemia. However, the splanchnic nerve stimulation-induced glucagon secretion at 1 mmol/l glucose was impaired in the streptozotocin-diabetic rats, but not in the neonatal streptozotocin-diabetic rats. These data suggest that the sensitivity of diabetic Alpha and Delta cells to sympathetic neural activation are blunted, whereas the sensitivity of Beta cells is enhanced in the diabetic animal model.

Animals↗
PubMed1992

Treatment of intraoperative hypertension with enflurane, nicardipine, or human atrial natriuretic peptide: haemodynamic and renal effects.

The purpose of this study was to assess the effects of the calcium entry blocker nicardipine and alpha human atrial natriuretic peptide (hANP) on antihypertensive and diuretic activity in hypertensive surgical patients. The site of the diuretic actions of these drugs along the nephron were also investigated by measuring the excretion rate of inorganic phosphate (PO4). Hypertension during gastrectomy was treated by increasing the concentration of enflurane, by nicardipine infusion (0.5-2.0 micrograms.kg-1 x min-1), or by hANP infusion (0.05-0.2 microgram.kg-1 x min-1) under general anaesthesia. Enflurane, nicardipine and hANP all decreased arterial pressure to the same extent. Urine flow, Na and PO4 excretion increased following the administration of nicardipine or hANP. Fractional distal reabsorption of sodium was suppressed from 89.7 +/- 2.8% to 82.1 +/- 5.0% by the hANP, but not by the nicardipine infusion. Creatinine clearance was increased by hANP infusion, but did not change in the nicardipine group. It is concluded that nicardipine and hANP can be used safely for the treatment of hypertension during surgery. Both drugs induced phosphaturic diuresis, but the site of action of the two drugs on the nephron may be different. Phosphate reabsorption is considered to occur largely in the renal proximal tubule, so that its appearance in the urine in increased quantities without the change of renal circulation in the nicardipine group suggests a proximal tubular action of this drug. However, the site of action of hANP in the kidney was not determined because GFR increased and distal sodium reabsorption was suppressed due to the drug infusion.

Absorption↗
PubMed1992

The thickness of the sound and periodontally diseased human cementum.

Cementum of teeth previously analysed for fluoride was re-examined in order to determine whether or not periodontal disease had affected the thickness of the tissue. In the periodontally diseased teeth the cementum was thinner than normal in the middle region of the root. The apical cementum, however, was significantly thicker in periodontally diseased than in the sound teeth of subjects over 60 yr old. This may account for the higher total fluoride levels previously reported in the apical cementum of these same teeth.

Adult↗
PubMed1992

Concurrent changes in sinusoidal expression of laminin and affinity of hepatocytes to laminin during rat liver regeneration.

Distribution of fibronectin, laminin, and collagens type I, III, IV, and V in the lobular regions of regenerating rat liver was studied by indirect immunofluorescence. Little or no laminin was detected in sham-operated controls throughout the experimental period, while it was detected in sinusoids of regenerating liver as early as 6 h after partial hepatectomy (PH). After reaching a maximum at 24 h, it decreased and was barely detectable 6 days after PH. Changes in the other extracellular matrix (ECM) proteins were evident 3 days after PH, but not earlier than 24 h. Hepatocytes isolated from regenerating rat livers were tested in a short term assay for attachment to the substrates coated with the ECM proteins. The attachment of hepatocytes to laminin substrates increased 12 h after PH, reached a maximum at 24 h, and decreased to the control level 6 days after PH, while that of the control remained constant. The attachment to fibronectin substrates was not different between regenerating livers and controls at any time point. The attachment to collagen did not change earlier than 24 h after PH, but increased slightly 3 days after PH. Primary rat hepatocytes cultured on the substrates coated with the ECM proteins were determined for replicative DNA synthesis in response to epidermal growth factor. Both in normal liver and in regenerating liver 24 h after PH, laminin was one of the most effective substrates in supporting the responsiveness of hepatocytes to the growth stimulus. Taken together, these results suggest the importance of hepatocyte-laminin interaction during the early stage of liver regeneration possibly in growth stimulation of hepatocytes and/or maintenance of hepatocyte-specific functions.

Animals↗
PubMed1992

Early midzonal oxidative stress preceding cell death in hypoperfused rat liver.

Intralobular heterogeneity of oxidative stress and its topographic relationship with cell death during low-flow hypoxia were shown in perfused rat liver by digital microfluorography using dichlorofluorescin diacetate, a fluorochrome sensitive to intracellular hydroperoxide formation, and propidium iodide, which labels the nuclei of nonviable cells. The surface of the liver loaded with two precursors was microscopically visualized, and the fluorescence of dichlorofluorescein, a highly fluorescent molecule generated by hydroperoxide-mediated dichlorofluorescin oxidation, was digitally processed. Dichlorofluorescein fluorescence significantly increased in midzonal regions as early as 20 minutes after starting the 25% low-flow hypoxia. At 40 minutes the fluorograph showed multiple dotted patterns, and the intensity peaked at 60 minutes. The onset of cell death studied by propidium iodide was observed at 40 minutes, and its topographic distribution corresponded to the dichlorofluorescein-enhanced midzonal regions. Allopurinol diminished the early midzonal oxidative stress and retarded the onset of cell death. The current findings show that xanthine oxidase-dependent oxidative stress and the resultant cell death during low-flow hypoxia are spatially restricted in the intermediate zone between the periportal and pericentral regions.

Animals↗
PubMed1992

Cushing's syndrome induced by hypersecretion of cortisol from only one of bilateral adrenocortical tumors.

A case of Cushing's syndrome induced by the unilateral (right side) dominance of cortisol secretion in the face of bilateral adrenal tumors is reported. The adrenal tumor resected on the right side was a so-called black adenoma and histologically without any findings of nodular hyperplasia. After resection of the adrenal adenoma, no findings of cortisol hypersecretion from the remaining adrenal tumor on the left side were observed until the present, suggesting that the tumor of the left adrenal gland is a nonfunctioning adenoma. These data imply that the adrenal adenomas have primarily developed from the adrenal gland itself, rather than from micronodular hyperplasia by corticotropin stimulation, and that one of these tumors produces excess hormones initially by corticotropin stimulation, but the other remains in cell proliferation.

Adenoma↗
PubMed1992

Influence of season on characteristics of epididymal and ejaculated semen in Meishan boars.

Most of the epididymal spermatozoa collected in all the seasons examined maintained an ability to move progressively, had a cytoplasmic droplet in the distal site of the middle piece, and were morphologically normal. Reduced desire to mount a dummy was not observed during the experimental period. Characteristics of ejaculated semen were not significantly altered throughout the year. However, progressive motility and acrosomal integrity of spermatozoa ejaculated between July and September were more susceptible to storage at 4 degrees C than spermatozoa ejaculated during the other months and acrosomal integrity of spermatozoa ejaculated during the 3 months was to freezing-thawing. These results indicate that the reproductive activity of Meishan boars in Japan is only slightly influenced by season, but semen ejaculated during the summer is less suitable for storage than that ejaculated during the other seasons of the year.

Journal Article↗
PubMed1992

A mechanism for glutamate toxicity in the C6 glioma cells involving inhibition of cystine uptake leading to glutathione depletion.

We have demonstrated that addition of L-glutamate in millimolar amounts to a culture of C6 glioma cells induced cell death within 24 h. The glutamate-induced toxicity in the C6 glioma cells was completely suppressed by adding L-cystine (0.4-1.0 mM), while the C6 cells degenerated in L-cystine-deprived culture medium. Kinetic studies of [35S]cystine and [3H]glutamate uptake showed that cystine competitively inhibited glutamate uptake, and conversely glutamate inhibited cystine uptake competitively, suggesting that C6 cells have a cystine/glutamate antiporter (system CG or Xc) similar to that already described in the periphery. Exogenous cystine (1 mM) stimulated a release of endogenous glutamate from C6 cells in a Na(+)-independent Cl(-)-dependent fashion. Thus, the antiporter normally transports glutamate out of and cystine into the cells. With the glutamate analogues tested, there was a good correlation between cytotoxicity and inhibition of cystine uptake. The de novo synthesis of glutathione was largely dependent upon the uptake of extracellular cystine. Intracellular levels of glutathione were dramatically decreased within 8-10 h by culture in glutamate-added or cystine-free medium. Vitamin E (100 microM), an antioxidant, rescued the death of C6 cells induced by glutamate exposure or by culture in cystine-deprived medium, but did not restore the apparent decrease of intracellular glutathione. Taken together, the present data strongly indicate that glutamate-induced cell death is initially due to inhibition of cystine uptake through the antiporter Xc system; such inhibition leads to glutathione depletion exposing the cells to oxidative stress. Excess of extracellular glutamate introduced from endogenous or exogenous roots might disorder this mechanism, resulting in cell death.

Animals↗
PubMed1992

Large-scale culture system of human CD4+ helper/killer T cells for the application to adoptive tumour immunotherapy.

A simple method for the rapid expansion of human CD4+ T cells with both helper and killer functions was established. CD4+ T cells separated from peripheral blood mononuclear cells using immunomagnetic beads were stimulated with immobilised OKT-3 monoclonal antibody (mAb) plus recombinant interleukin 2 (rIL-2) in 96 well culture plates. After 6 day-culture, the CD4+ T cells were restimulated by immobilised OKT-3 mAb for an additional 24 h, then inoculated into concentrated rotary-tissue culture bag and cultured for further 9 days. This procedure yielded a 3000-fold increase in cell number (about 3-5 x 10(9) per bag). Most of the cells (over 96%) continued to express CD4+ antigen and retained their capacity to produce IL-2. The activated CD4+ T cells showed marked cytotoxicity against Fc receptor positive tumour cells in the presence of OKT-3 mAb. Moreover, we succeeded in a specific targeting of the expanded CD4+ helper/killer T cells to c-erb B-2 positive tumour cells by means of anti-CD3 x anti-c-erb B-2 bispecific antibody. These results suggested that our established simple system will be available for the expansion of large number of CD4+ helper/killer T cells which may provide an efficient strategy for adoptive tumour immunotherapy.

Antibodies, Monoclonal↗
PubMed1992

Comparative immunohistochemical study on the expression of alpha B crystallin, ubiquitin and stress-response protein 27 in ballooned neurons in various disorders.

This report deals with a comparative study on the expression of alpha B crystallin, ubiquitin, stress-response protein 27 (srp 27), srp 72 and phosphorylated neurofilament protein (pNFP) by ballooned neurons in Pick's disease, Creutzfeldt-Jakob disease (CJD), amyotrophic lateral sclerosis (ALS), leptomeningeal carcinomatosis, anterior spinal artery syndrome and pellagra. Immunohistochemical techniques were used. alpha B Crystallin was expressed by the majority of ballooned neurons of Pick's disease and CJD, but not by those of the other disorders. Ubiquitin and srp 27 expression was also restricted to abnormal neurons of Pick's disease and CJD, but the proportion of stained cells was less than that expressing alpha B-crystallin. There was no evidence of ballooned neurons expressing srp 72. Except for those of pellagra patients, phosphorylated neurofilament protein (pNFP) was detected in most abnormal neurons. Our results suggest that the mechanisms involved in formation and maintenance of swollen neurons in Pick's disease and CJD may be different than those of ballooned neurons in the other entities studied.

Aged↗
PubMed1992

Immunohistochemical, ultrastructural and immunoelectron microscopic studies of spinal cord neurofibrillary tangles in progressive supranuclear palsy.

Immunohistochemical, ultrastructural and immunoelectron microscopic studies of spinal cord neurofibrillary tangles (NFTs) in progressive supranuclear palsy (PSP) were performed. The spinal cord NFTs reacted with antibodies to tau protein (tau-2), ubiquitin and Alzheimer neurofibrillary tangles (ANTs, Ab 39). Ultrastructurally, the NFTs consisted of bundles of straight fibrils. In longitudinal sections, the individual NFT fibrils appeared as straight fibrils with a diameter of approximately 15 nm. In cross sections, circular structures approximately 15 nm in diameter were seen, and some had a central density. Electron microscopic examination of specimens stained with the antibodies and by the modified Bielschowsky method revealed the products of the tau, ubiquitin and ANTs immunoreactions and silver deposits on the NFT fibrils. This is the first demonstration of the ultrastructure of spinal cord NFTs in PSP.

Adult↗
PubMed1992

Expression of glial fibrillary acidic protein (GFAP) by cultured angiofibroma stroma cells from patients with tuberous sclerosis.

Large dendritic cells were cultured from facial angiofibromas of six patients with tuberous sclerosis. The cells were examined immunocytochemically for expression of selected cytoskeletal and non-structural proteins and the results compared with the staining profiles obtained with normal skin fibroblasts and normal glial cells. In similarity to normal glia, the angiofibroma stroma cells expressed glial fibrillary acidic protein (GFAP). Conversely, by analogy to fibroblasts, the abnormal stroma cells produced fibronectin and did not react with the antibody to S-100 protein. By immunogold labelling it was established that GFAP and vimentin were co-localized in intermediate filaments of the angiofibroma cells.

Adolescent↗