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Biomedical subjects

A Masuda

Publications and source records attributed to A Masuda.

At least 325 records · Page 18Linked to original sources
PubMed1986

Improved Kupffer's gold chloride method for demonstrating the stellate cells storing retinol (vitamin A) in the liver and extrahepatic organs of vertebrates.

This paper describes our modification of the classical gold chloride technique for the demonstration of the perisinusoidal stellate cells in the liver. The results of the method as introduced by von Kupffer (1876) are unpredictable. Using our modification, high quality gold preparations can be obtained. The method allows selective staining of retinol (vitamin A)-storing stellate cells in the liver and extrahepatic organs of various vertebrates. The sensitivity of the reaction is comparable to that of the fluorescence method for retinol. The technique is simple and the preparations keep for several years. Formol fixed specimens can be counterstained with Sudan III or hematoxylin. We have also developed a simple technique for making "sinusoid-net preparations," removing the parenchymal cells by supersonication. The clear visualization of the stellate cells that results has made it possible to study the distribution of these cells.

Animals↗
PubMed1986

Acupuncture in the anesthetic management of eye surgery.

A study was conducted on twenty-four patients who underwent surgery for retinal detachment as to the clinical effect of acupuncture from the viewpoints of anesthetic dose, intraoperative changes in blood pressure and heart rate, postoperative analgesic state, nausea and vomiting. The patients were divided into two groups: group A, eleven patients receiving neuroleptanesthesia combined with acupuncture analgesia and group N, thirteen patients receiving usual neuroleptanesthesia without acupuncture. A significant difference was found in the dose of fentanyl, used as the narcotic, between group A (0.11 mg) and group N (0.48 mg). No difference was noted in blood pressure between the two groups, but it was high in group N in the postoperative period. There was no difference in heart rate between the two groups. Two patients from group A and five from group N required analgesics in the postoperative period. Nausea and vomiting were encountered in one patient in group A and three in group N. Therefore, it would seem that anesthesia in combination with acupuncture is capable of reducing the required dose of narcotic and offering more comfortable postoperative conditions than usual anesthesia alone.

Acupuncture Therapy↗
PubMed1986

Electron microscopic study on amyloid fibril formation in human lymph nodes.

The purpose of this investigation was to clarify the mechanisms of amyloid fibril formation in human lymph nodes. In our present study, amyloid deposition was observed diffusely in all compartments of the lymph nodes. The deposition form showed extremely characteristic findings in its morphological features. Namely, amyloid deposits mainly consisted of clusters of round or oval nodules. Each amyloid nodule was frequently enclosed with long-stretched cytoplasmic processes of abutting reticulum cells and/or macrophages. Amyloid fibrils often formed parallel amyloid bundles radiating to outlying sections of the nodule from the center. The amyloid bundles closely adhered to the cytoplasmic membrane of not only the abutting reticulum cells, macrophages and sinus endothelium but also to the lymphocytes and plasma cells. In the central portion of the amyloid nodules, a concentric core was also observed. The most interesting finding was the intracellular formation of amyloid fibrils in all cells, such as macrophages, reticulum cells, foreign body giant cells and lymphocytes in the process of degeneration. Some fibrils localized in the limited area of the cytoplasm and others appeared in all parts of the cells, including the nucleus. Their cell membranes were missing in several areas and the cell organella had gradually dissolved. Finally the cell residuums were completely replaced by amyloid fibrils and transformed into a nodular structure with radiating bundles of amyloid fibrils.

Aged↗
PubMed1986

Function of the follicular dendritic cell in the germinal center of lymphoid follicles.

The authors made an immunocytochemical examination of the germinal centers (GCs) of (1) lymph follicles in physiological lymph nodes and (2) extra-nodal tissues of divergent diseases including thyroid disorders, rheumatoid arthritis, Warthin's tumor and Kimura's disease (Eosinophilic lymphfolliculoid granuloma). In these germinal centers, the presence of immunoglobulins (IgG and IgM), early acting complement components (C1q, C4, C3c, C3d), receptors for C3b and C3d and dendritic reticulum cell-1 was demonstrated in lace-like network patterns which were proven electron-microscopically to coincide with the surface of follicular dendritic cells. IgE was distributed in a lace-like pattern in the GCs of proliferating follicles of Kimura's disease, in which the lysis of follicles was frequently observed. This lysis appeared to be related to the presence of complement components. In the germinal centers of extra-nodal tissues, including the thyroid tissues accompanying the lymph follicles, rheumatoid arthritis synovial tissues as well as Warthin's tumors, thyroglobulin, rheumatoid factor and salivary amylase were detected as specific antigens, occurring in lace-like patterns. It is possible that follicular dendritic cells may play a role in the genesis of GCs and be responsible for the immune response through C3 receptors.

Adenolymphoma↗
PubMed1986

Histologic and autoradiographic studies on the forestomach of hamsters treated with 2-tert-butylated hydroxyanisole, 3-tert-butylated hydroxyanisole, crude butylated hydroxyanisole, or butylated hydroxytoluene.

The inductions of hyperplasia and neoplastic lesions in the forestomach of Syrian golden hamsters by 2-tert-butylated hydroxyanisole [(2-tert-BHA) CAS: 121-00-6], 3-tert-butylated hydroxyanisole [(3-tert-BHA) CAS: 88-32-4], crude butylated hydroxyanisole [(BHA) CAS: 25013-16-5], and butylated hydroxytoluene [(BHT) CAS: 128-37-0] were compared histopathologically and autoradiographically. In hamsters fed the 2-tert-BHA diet, severe hyperplasia developed from week 4, reaching a maximum level in week 16 of 0.56 cm/10 cm basement membrane (bm), and papillomatous lesions appeared in week 16 (0.13 cm/10 cm bm). In hamsters fed 3-tert-BHA or crude BHA, severe hyperplasia developed from week 1, which reached a maximum level in week 4 of 3.63 cm/10 cm bm with 3-tert-BHA and 5.10 cm/10 with crude BHA; it then decreased. Papillomatous lesions were found in week 3 in hamsters fed 3-tert-BHA and in week 4 in hamsters fed crude BHA; they increased to maximum levels in week 16 of 0.50 cm/10 cm bm with 3-tert-BHA and 0.29 cm/10 cm bm with crude BHA. Mild hyperplasia occurred slightly more often in hamsters fed the BHT diet than in the control group. BHT induced no severe hyperplasia and papillomatous lesions. Changes in the labeling index of the forestomach epithelium paralleled the histologic changes, except in hamsters fed the BHT diet in which no significant increase in the labeling index was observed throughout the experiment. These data suggest that the tumorigenic action of crude BHA on hamster forestomach is largely due to 3-tert-BHA and that BHT does not induce forestomach tumors in hamsters.

Animals↗
PubMed1985

The satiety effect of growth hormone-releasing factor in rats.

The effect of growth hormone-releasing factor (GRF) on feeding behavior in rats was examined. Starvation-induced feeding was suppressed by intraventricular administration of 1 nmol and 4 nmol of synthetic human GRF (hGRF). Food intake was not affected when the peptide was administered by intraperitoneal injection. Furthermore, centrally administered hGRF also suppressed feeding in hypophysectomized rats. These results suggest that GRF suppression of food intake is mediated through the central nervous system independent of its effect on pituitary growth hormone secretion.

Animals↗
PubMed1985

Defective endocytosis of low-density lipoprotein in monensin-resistant mutants of the mouse Balb/3T3 cell line.

Two monensin-resistant clones show similar low-density lipoprotein binding activity but less internalization or degradation of low-density lipoprotein than the parental Balb/3T3 or other resistant clone. Sterol synthesis from radioactive acetate in the resistant mutant, MO-5, is inhibited by more than 70% of control in the presence of tenfold higher amounts of low-density lipoprotein than the dose that inhibits the parental Balb/3T3 to similar level. 3-Hydroxy-3-methylglutaryl coenzyme A reductase activity of Balb/3T3 and MO-5 is inhibited by 48% and 27% of control, respectively, in the presence of 10 micrograms/ml of low-density lipoprotein. Colloidal silica gradient centrifugation shows that transport of low-density lipoprotein from the surface membrane to the lysosome is much slower in MO-5 cells than in Balb/3T3 cells. Down regulation of low-density lipoprotein receptors on the cell surface in Balb/3T3 is observed by exposing the cells to 5-15 micrograms/ml low-density lipoprotein, whereas only slight if any down regulation is observed when MO-5 cells are treated with low-density lipoprotein. The altered endocytosis of low-density lipoprotein behaves as a dominant trait in hybrids of MO-5 and THO2-2, a derivative of Balb/3T3 resistant to both ouabain and 6-thioguanine.

Animals↗
PubMed1985

Dexamethasone-induced changes in morphology and keratin organization of rat thymic epithelial cells in primary culture.

Dexamethasone (DM)-induced changes in morphology and keratin organization of rat thymic epithelial cells (TECs) in primary culture were studied. The morphology and keratin organization of TECs were greatly altered by the addition of more than 10 nM DM. In control cultures, small slender cells were predominant and grew faster than cells of other types. Most of them had keratin bundles on day 3, but lost the bundles on day 7. In experimental cultures containing more than 10 nM DM, the morphology of TECs altered to a polygonal form and the TECs formed colonies. They had fine interlacing bundles of keratin filaments all over the cytoplasm, and the bundles were maintained or increased in number with the day of culture. Keratin proteins in TECs treated with 100 nM DM for 7 days were 2-fold for 46 500 D, 4-fold for 49 000 D, 1.7-fold for 52 000 D and 3.5-fold for 55 500 D keratins to those in control TECs, respectively. Growth of TECs was inhibited by the addition of more than 10 nM DM. The effects of DM were reversible to some extent, for the morphology and keratin organization of TECs gradually changed into the control type by the removal of DM. These results suggested that DM greatly involved the growth and differentiation of rat TECs.

Animals↗
PubMed1985

Effects of sodium L-ascorbate and related compounds on rat stomach carcinogenesis initiated by N-methyl-N'-nitro-N-nitrosoguanidine.

The modifying effects of 3 antioxidants, sodium L-ascorbate (SA), ascorbic acid (AA) and sodium erythorbate (SE) on two-stage gastric carcinogenesis in F344 rats initiated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) were investigated. Administration of 5% SE in the diet significantly decreased the incidence of dysplasia of the pylorus and, more marginally the incidence of papilloma of the forestomach, whereas administration of 5% and 1% SA and 5% AA in the diet was not associated with effect. These results suggest that SE exerts a weak inhibitory effect on gastric carcinogenesis.

Animals↗
PubMed1985

The effect of free fatty acids on growth hormone (GH)-releasing hormone-mediated GH secretion in man.

The effect of FFA on GH-releasing hormone (GHRH)-mediated secretion of GH was examined in six normal young men. Three of the men were infused with 250 ml of a lipid-heparin solution at 1.67 ml/min for 150 min, and the other three were given an equivalent volume of saline in the same manner. Thirty minutes after the start of infusion, 100 micrograms GHRH (the 44-amino acid form) were injected iv, and plasma GH and FFA were measured. One week later, the same men participated in an identical experiment, but the ones who had received lipid-heparin previously were given saline and vice versa. In both experiments, plasma FFA increased to 2.25 +/- 0.16 meq/liter (mean +/- SEM) 60 min after the start of lipid-heparin infusion, whereas FFA levels did not change significantly in the saline-treated group. Mean plasma GH levels reached peak concentrations in both groups 30 min after GHRH treatment. However, the peak GH response when lipid-heparin was given was significantly diminished (8.4 +/- 1.7 ng/ml), compared with the peak response when saline was given (28.9 +/- 7.1 ng/ml). These data suggest that plasma FFA elevations induced by lipid-heparin infusion inhibit GH secretion induced by GHRH.

Adult↗
PubMed1985

The effect of glucose on growth hormone (GH)-releasing hormone-mediated GH secretion in man.

The effect of glucose on GH-releasing hormone (GHRH)-mediated GH secretion was examined in six normal young men. In two paired experiments, the six men drank a 75-g glucose solution or an equal volume of water 30 min before receiving, iv, 100 micrograms of the 44-amino acid form of human pancreatic GHRH (hGHRH-44). One week later, the same men underwent an identical experimental protocol in a cross-over trial. Basal plasma GH concentrations before hGHRH-44 administration were not statistically different in the two experiments [glucose experiment, 2.1 +/- 0.1 (+/- SE) ng/ml; water experiment, 2.6 +/- 0.6 ng/ml]. The mean peak plasma GH level occurred 30 min after hGHRH-44 administration in both experiments. However, the mean GH response was significantly diminished when the men received glucose (8.12 +/- 1.12 ng/ml) compared to that when they received only water (23.70 +/- 8.46 ng/ml; P less than 0.01). Thus, hyperglycemia may exert an inhibitory effect on the plasma GH response to hGHRH-44.

Adult↗
PubMed1985

Plasma GH responses to GHRH and insulin-induced hypoglycemia in man.

Changes in plasma GH levels in response to an intravenous bolus injection of 200 micrograms GHRH-44 or 0.1 U/kg body weight regular insulin were examined in normal men who were pre-treated with 200 micrograms GHRH-44 or 0.1 U/kg body weight regular insulin 120 min in advance. The prior bolus injection of GHRH-44 inhibited the plasma GH response to the subsequent administration of GHRH-44 whereas the plasma GH response to the subsequent injection of insulin was not influenced by the prior administration of GHRH-44. The prior administration of insulin attenuated the plasma GH response to the subsequently given GHRH-44. These results suggest that desensitization of GHRH receptors in somatotrophs and/or somatostatin hypersecretion induced by increase in plasma GH levels following the prior GHRH-44 administration may be involved in the mechanism by which the prior GHRH-44 administration or insulin-induced hypoglycemia suppressed plasma GH responses to the following GHRH-44 administration. Sudden suppression of somatostatin secretion, which causes rebound of GH secretion, may occur in insulin-induced hypoglycemia.

Adult↗
PubMed1985

The inter- and intra-subject variabilities of plasma GH response to human growth hormone-releasing hormone (1-44) NH2 in men.

The effects of intravenously given human growth hormone-releasing hormone (1-44) NH2 (hGRH-44) on growth hormone (GH) secretion were studied in normal men. A wide variability of intersubject GH response to hGRH-44 was observed. The peak plasma GH levels in response to 50, 100 and 200 micrograms hGRH-44 in 7 normal men were 9.1 +/- 3.2 ng/ml (Mean + SEM), 19.3 +/- 3.3 ng/ml and 22.4 +/- 4.0 ng/ml, respectively. Both the mean peak values for plasma GH response to 100 and 200 micrograms were significantly greater than that for 50 micrograms hGRH-44 injection (p less than 0.01), although there was no significant difference of the mean peak plasma GH values and mean concentrations at each time point, except for those at 120 min, when 100 or 200 micrograms hGRH-44 was administered. A significant difference in the mean amount of plasma GH secreted in response to hGRH-44 was observed only between 50 and 200 micrograms hGRH-44 injection (p less than 0.01). Furthermore, a dose-related plasma GH increase in response to hGRH-44 was not always observed in each subject. In contrast to the wide intersubject variability, the difference among responses of plasma GH to 100 micrograms or 200 micrograms of hGRH-44 given at multiple times separated by intervals of at least 1 week in each individual was relatively small.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1985

Ubiquity of the repetitive epitope of the CS protein in different isolates of human malaria parasites.

Sporozoites of the human malaria Plasmodium falciparum and Plasmodium vivax obtained from a large number of endemic areas were screened with species-specific monoclonal antibodies that recognize the repeated epitopes of the respective circumsporozoite (CS) proteins. By using a two-site immunoradiometric assay, it was determined that all the parasite isolates of a given species react with a single monoclonal antibody, indicating the presence of a common repeated epitope. Polyacrylamide gel electrophoresis, followed by Western blot, showed that the CS proteins of the various isolates differed in their apparent m.w.

Animals↗
PubMed1985

[Somatic cell mutants with altered receptor and endocytosis activities].

Binding and endocytosis are responsible for cellular uptake of a wide variety of physiologically active ligands. We have selected somatic cell mutants with altered endocytosis activity for low-density lipoprotein, insulin, and epidermal growth factor. Of these mutants, the one with altered response to epidermal growth factor shows aberrant growth behavior in soft agar.

Animals↗