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S Furuya

Publications and source records attributed to S Furuya.

At least 91 records · Page 5Linked to original sources

Ganglioside GD1 alpha in cerebellar Purkinje cells. Its specific absence in mouse mutants with Purkinje cell abnormality and altered immunoreactivity in response to conjunctive stimuli causing long-term desensitization.

The alpha-series ganglioside, IV3NeuAc,III6NeuAcGgOse4-Cer(GD1 alpha), was previously identified as a minor constituent in bovine brain gangliosides (Hirabayashi, Y., Hyogo, A., Nakao, T., Tsuchiya, K., Suzuki, Y., Matsumoto, M., Kon, K, and Ando, S. (1990) J. Biol. Chem. 265, 8144-8151). In the present study, we have generated a specific mouse monoclonal antibody against GD1 alpha and explored the distribution of GD1 alpha in murine central nervous system. In adult rat brain, GD1 alpha occurred as a minor constituent, and its expression was exclusively detected in the forebrain, the midbrain and the cerebellum. In the mouse cerebellum, the content of GD1 alpha was reduced significantly in the Purkinje cell-deficient mutants, lurcher (Lc/+), staggerer (sg/sg), and Purkinje cell degeneration (pcd/pcd), but were not reduced in the weaver (wv/wv) mutant, which loses mostly granule cells. The GD1 alpha synthase, assayed in cerebellar microsomes, was also reduced in Purkinje cell-deficient mutants. Immunohistochemistry showed that the staining for GD1 alpha in rat and mouse cerebella was mostly found in the proximal dendrites and cell bodies of Purkinje cells. Also, it appeared slightly in the processes of Bergmann glial cells. The immunoreactivity of GD1 alpha disappeared specifically from the Purkinje cell dendrites and the Bergmann glial processes after co-application of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and 8-bromo-guanosine 3':5'-cyclic monophosphate, which induced long-term desensitization of the AMPA-selective glutamate receptors in Purkinje cells. The present data provide suggestive evidence that GD1 alpha ganglioside is enriched in Purkinje cells and may have a role in Purkinje cell functions in the cerebellum.

Animals↗

Intracellular calcium responses and shape conversions induced by endothelin in cultured subepithelial fibroblasts of rat duodenal villi.

Subepithelial fibroblasts of rat duodenal villi were cultured and the physiological characteristics were studied using fura-2 fluorescence. The intracellular calcium concentration (Ca2+i) responded to various substances, i.e., endothelins (ET1 and ET3), substance P, serotonin, angiotensin II, ATP, and bradykinin. The Ca2+i responses to ET1 (> 0.1 nM) and ET3 (> 1 nM) were transient and sometimes followed oscillations that consisted of an initial Ca2+ release from the intracellular store and a sustained Ca2+ influx. Simultaneously with Ca2+i measurement, changes in the cell shape were monitored using fluorescence intensity upon 360-nm excitation. Stellate cells (with thick cell body and slender processes), formed as a result of 1 mM dibutyryl(Bt2)-cAMP treatment, began to change immediately after the short-term application of the endothelin and became flat about 20 min later. This process was not affected by the depletion of extracellular Ca2+ or by the treatment with BAPTA acetoxymethyl ester that completely suppressed the Ca2+i response. Substance P (> 100 nM) increased Ca2+i, but did not induce any morphological changes. The conversion of the shape from flat to stellate, induced by Bt2cAMP treatment, was not accompanied by any Ca2+i change. BQ-123, a specific blocker of the ETA-type receptor, did not block either Ca2+i change or shape conversion at low (100 nM) concentration. The results indicated that shape conversion in subepithelial fibroblasts did not require any Ca2+i response. Our findings regarding the characteristics of subepithelial fibroblasts in intestinal villi imply a functional similarity to astrocytes in the brain.

Animals↗

Transcriptional activities of a winged bean Kunitz chymotrypsin inhibitor gene promoter in stable and transient expression systems.

Sequential deletions of the promoter region of the WCI-3b gene, which encodes the major chymotrypsin inhibitor of winged bean, were constructed and their expression was analyzed in transgenic tobacco plants and in bombarded winged bean seeds. In transgenic tobacco plants, a critical promoter region which is important for high levels of expression in seeds was identified, but deletion of this region had essentially no effect when bombarded into winged bean seeds.

Chymotrypsin↗

Novel lacto-ganglio type gangliosides with GM2-epitope in bovine brain which react with IgM from a patient of the amyotrophic lateral sclerosis-like disorder.

A motor neuron disorder resembling that of amyotrophic lateral sclerosis was found in a patient who had received the intramuscular administration of a mixture of bovine brain gangliosides (Yuki, N., Sato, S., Miyatake, T., Sugiyama, K., Katagiri, T., and Sasaki, H. (1991) Lancet 337, 1109-1110). A very high titer of anti-GM2 IgM was detected in the patient's serum and the patient quickly recovered after plasmapheresis. The clinical course of the patient appeared to be different from amyotrophic lateral sclerosis and the anti-GM2 IgM was thought to be the culprit. The IgM reacted with GM2, GM1b-GalNAc, SPG(alpha 2-3)-GalNAc, and GD1a-GalNAc, but not with GA2 or GD2, meaning that the epitope recognized by the IgM was the GM2-like terminal structure, GalNAc beta 1-4(Neu-Ac alpha 2-3)Gal beta 1-. In this study, we found two novel GM2-epitope containing gangliosides, X1 and X2, in bovine brain gangliosides by TLC immunostaining using the patient's IgM. They were characterized as unique lacto-ganglio type gangliosides containing the following branching structures. [formula: see text] Their unusual structures may be immunogenic to humans to induce anti-GM2 antibody.

Aged↗

Characteristics of cultured subepithelial fibroblasts of rat duodenal villi.

Subepithelial fibroblasts, which form a cellular network beneath the epithelium of rat intestinal villi, were cultured, and their morphological characteristics were examined. These fibroblasts, which migrated from epithelium-free villi (isolated primarily from duodenum) were flat in shape after 2 days of culture. The flat cells, each resembling a maple leaf, were rich in bundles of microfilaments, and were connected to each other by a few small gap junctions, ascertained from freeze-fracture and dye-coupling experiments. The morphology of the flat cells changed to a stellate form, with thin processes, within 30 min-1 h of reducing the serum concentration and adding dibutyryl cyclic AMP (dBcAMP), forskolin, and cholera toxin. Upon removal of dBcAMP and addition of fetal calf serum, the cells rapidly reassumed their original flat shape. Cells that were stellate in the presence of dBcAMP reassumed a flat morphology within several minutes after the addition of endothelin-1. This conversion occurred with or without extracellular Ca2+. An accompanying rearrangement of the cytoskeleton during shape conversion was observed by fluorescence immunohistochemistry.

Actins↗

Intussusception caused by a carcinoma of the cecum during pregnancy: report of a case and review of the literature.

A case of intussusception due to a carcinoma of the cecum during pregnancy is reported. A 27-year-old pregnant female was admitted to Shimodate Municipal Hospital because of abdominal pain, nausea and vomiting. Her abdomen was distended, and a relatively hard mass was palpable in the right hypochondrium. Following a diagnosis of intussusception by ultrasonography, a laparotomy was performed. The lesion causing the intussusception was found to be a carcinoma of the cecum, and thus a right hemicolectomy with lymph node dissection was carried out. Histological examination revealed that the tumor was a well-differentiated adenocarcinoma which had invaded the muscularis propria but was superficial to the subserosa. None of the lymph nodes were cancerous. The incidence of colonic cancer above the peritoneal reflection during pregnancy is very low. Only 24 cases have been previously reported; our patient is only the 25th case, as well as being the first case demonstrating Dukes' A. Due to the intussusception, ultrasonography was effective for diagnosis and the patient was able to undergo a curative operation at an earlier stage than other patients.

Adenocarcinoma↗

Calyculin A, protein phosphatase inhibitor, enhances capacitation of human sperm.

OBJECTIVE: To examine the effects of protein phosphatase inhibitors on capacitation and protein phosphorylation in human sperm. DESIGN: The chlortetracycline (CTC) fluorescence assay was used to monitor capacitated sperm treated with or without protein phosphatase inhibitors. Capacitation was confirmed by the ability of sperm to undergo the acrosome reaction in response to Ca++ ionophore A23187 or mouse zonae pellucidae. 32P-labeled sperm phosphoproteins were analyzed by one-dimensional gel electrophoresis to detect the effects of protein phosphatase inhibitors on protein phosphorylation. RESULTS: The treatment of sperm with calyculin A resulted in the following: [1] the rapid appearance of the clear perimeter pattern, specifically, distribution of fluorescence over the entire head exhibiting a bright perimeter and bright midpiece, in a dose-dependent manner in the 1 to 100 nM range; [2] an accelerated ability to undergo the acrosome reaction; and [3] an enhanced phosphorylation of sperm phosphoproteins in a dose-related fashion in the 1 to 100 nM range. A similar stimulatory effect was observed only with a 100-fold higher concentrations of okadaic acid, another protein phosphatase inhibitor. CONCLUSION: Our results strongly suggest that protein phosphorylation and dephosphorylation may be involved in the regulation of human sperm capacitation.

Acrosome↗

Effect of epidermal growth factor on human sperm capacitation.

OBJECTIVE: To examine the effect of epidermal growth factor (EGF) on human sperm capacitation and the involvement of protein phosphorylation in the regulation of the EGF action. DESIGN: Human sperm were capacitated in modified Krebs-Ringer's bicarbonate medium of Biggers, Whitten, and Whittingham in the presence of EGF and various agents known to phosphorylate the EGF receptor. The chlortetracycline fluorescence assay was used to monitor capacitated sperm. Capacitation was confirmed by the ability of sperm to undergo the acrosome reaction in response to solubilized mouse zonae pellucidae (ZP). RESULTS: In 15 minutes, the appearance of the clear perimeter pattern increased significantly in the sperm treated with 100 ng/mL EGF compared with the controls. In EGF-treated sperm, the percent clear perimeter pattern remained stable for 3 hours without affecting the acrosome reaction pattern and the motility. Epidermal growth factor stimulated the appearance of the clear perimeter pattern at concentrations > 100 pg/mL. The stimulation by EGF was attenuated by the treatment with genistein, 12-O-tetradecanoylphorbol-13-acetate, or thapsigargin. In sperm that were incubated in the presence of 100 ng/mL EGF for 30 minutes and further induced the acrosome reaction by mouse ZP, the percent acrosome reaction pattern increased significantly compared with the controls. CONCLUSION: Epidermal growth factor stimulates human sperm capacitation by activating the tyrosine kinase of the EGF receptor which is regulated by multisite phosphorylation.

Acrosome↗

[Effect of epidermal growth factor (EGF) on mouse sperm capacitation].

The effect of epidermal growth factor (EGF) on the kinetics of mouse sperm capacitation was examined. The chlortetracycline (CTC) fluorescence assay was used to monitor capacitated sperm, featuring a B pattern. One hundred ng/ml EGF significantly stimulated capacitation at 15 minutes after the addition. However, 0.1 pg/ml EGF did not stimulate capacitation. EGF affected neither the motility nor the appearance of the S or AR pattern. The EGF-induced stimulation of capacitation was attenuated by 20 micrograms/ml genistein, an inhibitor of protein tyrosine kinase, or by 100 ng/ml thapsigargin, a non-phorbol tumor promoter, which inhibits EGF action by enhancing phosphorylation of the threonine 669 residue of the EGF-receptor. However, 3 ng/ml 12-O-tetradecanoly phorbol 13-acetate (TPA), a stimulator of protein kinase C, did not attenuate the appearance of the B pattern enhanced by 100 ng/ml EGF. These data suggest that EGF stimulates mouse sperm capacitation by activating the tyrosine kinase of the EGF-receptor which is regulated by multisite phosphorylation.

Animals↗

Effects of modulators of protein kinase C on human sperm capacitation.

OBJECTIVE: To examine the effects of stimulators or inhibitors of protein kinase C on capacitation and protein phosphorylation in human sperm. DESIGN: Capacitated sperm treated with or without modulators of protein kinase C were monitored by the chlortetracycline fluorescence assay. Capacitation was confirmed by the ability of sperm to undergo the acrosomal reaction in response to mouse zonae pellucidae. 32P-labeled sperm phosphoproteins were analyzed by one-dimensional gel electrophoresis to detect the effect of protein kinase C stimulator, 12-O-tetradecanoyl-phorbol-13-acetate, on protein phosphorylation. RESULTS: The treatment of sperm with protein kinase C stimulators resulted in the following: [1] the rapid appearance of the clear perimeter pattern, featuring distribution of fluorescence over the entire head exhibiting a bright perimeter and bright midpiece; [2] an accelerated ability to undergo the acrosomal reaction; and [3] an enhanced phosphorylation of 57.5-kd sperm phosphoprotein. Furthermore, these stimulatory effects were inhibited by protein kinase C inhibitors. CONCLUSION: Protein phosphorylation mediated by protein kinase C may be involved in the regulation of human sperm capacitation.

Acrosome↗

Effect and distribution of intravenously injected 125I-endothelin-1 in rat kidney and lung examined by electron microscopic radioautography.

The morphological effect of endothelin-1 (ET-1) and the distribution of endothelin-binding sites on the kidney and lung was investigated ultrastructually by intravenous injection of [125I]-ET-1 into rats. About 10% decrease of the diameter of glomeruli was observed at 10 min after the injections of ET-1 or [125I]-ET-1 (1.3-2.4 nmole/kg). When localization of [125I]-ET-1 in the kidney was examined by light and electron microscopic radioautography, silver grains were preferably localized on the fenestrated endothelial cells of glomeruli and peritubular capillary endothelial cells. Some grains were also localized on the interdigitating processes of urinary tubules. Quantitative analysis of silver grains in the glomeruli showed that 83% of grains were located on the fenestrated endothelial cells, 12% on the podocytes of visceral cells, and 5% on mesangial cells at 10 min. After 60 min, 50% of silver grains were incorporated into the cytoplasm of fenestrated endothelial cells. In contrast to glomeruli, silver grains were rare on the arteries and large arterioles. However, a few silver grains were often observed on the smooth muscle cells of small arterioles (8-20 microns in diameter). In the lung, 70% of silver grains were located on the alveolar capillary endothelial cells. These results indicate the abundance of ET receptors on the glomerular fenestrated endothelium, peritubular fenestrated endothelium and alveolar capillary endothelium.

Animals↗

Binding of 125I-endothelin-1 to fat-storing cells in rat liver revealed by electron microscopic radioautography.

Localization of intravenously injected [125I]-endothelin-1 was examined in rat liver by light and electron microscopic radioautography. At 10 min after injection, silver grains were localized along the sinusoidal wall, i.e., mostly on the thin processes of fat-storing cells and sinusoidal endothelial cells, and also on the Kupffer cells and the microvilli of hepatocytes. About 35% of the total silver grains were located on the processes of fat-storing cells at 10 min. The grain density (number of silver grains/cell area) of fat-storing cells was three-fold that of Kupffer cells, and 18-fold that of hepatocytes. At 60 min, 60% of the total grains were observed on the fat-storing cells, though the value of grain density was not changed. Silver grains were internalized into the cytoplasm of fat-storing cells and often associated with multivesicular bodies. In contrast, the grain density of endothelial cells and Kupffer cells decreased with time. These results indicate that hepatic fat-storing cells have a considerable number of endothelin-binding sites, and incorporate bound endothelin into cytoplasm.

Animals↗

Proliferative activity of cutaneous melanocytic neoplasms defined by a proliferating cell nuclear antigen labelling index.

To evaluate the proliferative activity of benign, borderline and malignant cutaneous melanocytic neoplasms, 30 cases of malignant melanoma (MM) and 41 cases of naevi were studied by immunostaining using a monoclonal antibody against proliferating cell nuclear antigen (PCNA). PCNA is a nuclear antigen expressed in the late G1 and S phase and serves as a marker of proliferating cells. Invasive MM and MM in situ showed much higher PCNA positivity rates than melanocytic naevi (invasive MM, 18.0%; MM in situ, 11.3%; ordinary melanocytic naevi, 2.6%). The PCNA positivity rate did not increase significantly with the thickness of MM. Among ordinary melanocytic naevi, junctional naevi had a higher PCNA positivity rate than compound or intradermal naevi. Mean PCNA positivity rates for Spitz's naevi and sporadic dysplastic naevi were within the range for ordinary melanocytic naevi, indicating the benign nature of both types of naevus. Contrary to some previous studies, MM in situ showed high proliferative activity, indicating that cells of MM in situ are actively proliferating. This study clearly demonstrates that MM and various types of naevi can be separated according to differences in proliferative activity defined by the PCNA labeling index.

Antibodies, Monoclonal↗

Protein phosphorylation regulates the mouse sperm acrosome reaction induced by the zona pellucida.

Recently, the ligand-receptor signal transduction mechanism has been implicated in mediating the zona pellucida (ZP)-induced acrosome reaction. Little is known about the role of protein phosphorylation in this specific event. We examine whether modification of protein phosphorylation and dephosphorylation affects the kinetics of the acid-solubilized ZP-induced acrosome reaction of mouse sperm. Mouse epididymal sperm were incubated in modified Krebs-Ringer bicarbonate medium for a period of 90 to 120 min and then treated with 2 acid-solubilized ZP/microliters for an additional 60 min. The chlortetracycline fluorescence assay was used to monitor the acrosome reaction. Capacitated sperm were inhibited from undergoing acid-solubilized ZP-induced acrosome reaction in the presence of an inhibitor of cyclic nucleotide-dependent protein kinase, H8; activators of the Ca(2+)- and phospholipid-dependent protein kinase (protein kinase C); an inhibitor of phosphatases 1 and 2A, okadaic acid; or an inhibitor of protein tyrosine kinases, genistein. The addition of inhibitors of protein kinase C, such as staurosporine, H7, and protein kinase C [19-36] pseudosubstrate, inhibited the phorbol ester-dependent inhibition of the acid-solubilized ZP-induced acrosome reaction. The present study suggests that protein phosphorylation and dephosphorylation play a regulatory role in the process of the ZP-induced acrosome reaction.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

Effects of modulators of protein kinases and phosphatases on mouse sperm capacitation.

We examined effects of modulators of protein kinases and phosphatases on the kinetics of mouse sperm capacitation. The chlortetracycline fluorescence assay was used to monitor the process of capacitation (in terms of the appearance of the B pattern). The treatment of sperm with dibutyryl cyclic AMP (cAMP) or dibutyryl cGMP resulted in a higher percentage B pattern at various times during capacitation compared with the control. The addition of 100 microM H8 inhibited the cyclic nucleotide-dependent stimulation of capacitation. Tumor promotors, 12-O-tetradecanoyl phorbol 13-acetate (TPA; a stimulator of protein kinase C) and okadaic acid (an inhibitor of protein phosphatases 1 and 2A), induced a rapid appearance of the B pattern (15 min after addition) and maintained a percentage B pattern similar to that of the control in the later period of capacitation. An inhibitor of protein kinase C, staurosporine, inhibited the TPA-dependent acceleration of capacitation. Furthermore, the addition of genistein, an inhibitor of protein tyrosine kinases, resulted in a strong inhibition of capacitation. All agents tested did not affect sperm motility. These data suggest that protein phosphorylation and dephosphorylation may play regulatory roles in mediating mouse sperm capacitation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

The effects of feed intake and purified cellulose on the endogenous ileal amino acid flow in growing pigs.

The effects of level of feed intake (0.8, 1.2 and 1.6 kg/d) and body-weight of the pig (49 and 92 kg) in Expt 1, and dietary neutral-detergent fibre (NDF; 30, 60, 90, 120 and 150 g/kg) in Expt 2 on the endogenous ileal flow of amino acids (AA) and nitrogen were studied with protein-free diets into which purified wood cellulose was incorporated at the expense of maize starch. In Expt 1, one of the protein-free diets containing 90 g NDF/kg was used. Female pigs were fitted with a simple 'T' cannula at the terminal ileum. In Expt 1, the endogenous ileal AA and N flow, expressed as g/kg dry matter (DM) intake, decreased significantly (P < 0.05) with increasing DM intake, except for proline. By contrast, the values expressed as g/d remained constant. There was no significant difference in endogenous ileal flow (P > 0.05) between initial body-weights of 45 and 90 kg except for histidine, isoleucine, phenylalanine, threonine, valine and serine, in which the ileal flow determined at the higher body-weight was significantly higher (P < 0.05). In Expt 2, the effects of dietary cellulose levels on the endogenous ileal flow of AA and N were not significant (P > 0.05), although the values tended to increase as dietary cellulose levels increased for most AA and for N. It is concluded that the daily endogenous ileal flow of AA and N remains relatively similar at different DM intake and cellulose levels. Therefore, correction of apparent ileal digestibility of AA and N to the true ileal digestibility should be made with the endogenous ileal flow values expressed on a daily amount basis, not the values expressed on a DM intake basis.

Amino Acids↗