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Biomedical subjects

M Hayama

Publications and source records attributed to M Hayama.

At least 37 records · Page 2Linked to original sources
PubMed2000

Helicobacter pylori infection produces expression of a secretory component in gastric mucous cells.

Helicobacter pylori infection induces the expression of a secretory component (SC) in gastric epithelial cells. We investigated the cell lineage of the SC- and immunoglobulin (Ig) A-expressing epithelial cells in H. pylori-infected gastric mucosa. Materials were obtained by means of gastric biopsy from H. pylori-infected patients (24 cases) before and after the eradication of H. pylori, from five normal uninfected volunteers, and from three gastrectomy cases. Acetic acid-ethanol-fixed and paraffin-embedded specimens were examined using histochemical staining for gastric mucins (periodic acid oxidation-thionine Schiff reaction-concanavalin A-horse radish peroxidase staining) by means of immunostaining for gastric mucins (45M1 and HIK1083), intestinal cells (MUC2 and CD10), Ki67, H. pylori, SC, and IgA. The SC and IgA were not found in normal gastric mucosa. The expressions of the SC and IgA in gastric surface mucous cells and mucous neck cells in the generating zone of the gastric mucosa of H. pylori-infected patients were significantly higher before eradication of H. pylori than after the eradication. These mucous cells have the potential for SC-mediated translocation of IgA into the gastric lumen, and this may act as part of the antibacterial defense system against H. pylori infection in the gastric generating zone.

Adult↗
PubMed2000

Transforming growth factor-alpha stimulates prostaglandin generation through cytosolic phospholipase A(2) under the control of p11 in rat gastric epithelial cells.

The regulatory effects of transforming growth factor (TGF)-alpha on phospholipase A(2) (PLA(2)) isozymes contributing to prostaglandin generation in rat gastric epithelial RGM1 cells were examined. Stimulation with TGF-alpha for 24 h time-dependently induced prostaglandin E(2) generation with an increase in cyclo-oxygenase-2 protein. The TGF-alpha-induced prostaglandin E(2) generation was suppressed by NS-398, a cyclo-oxygenase-2 inhibitor. TGF-alpha stimulated the activity and the protein synthesis of cytosolic PLA(2) (cPLA(2)). A time-dependent increase in cPLA(2) protein occurred in parallel with PGE(2) generation, which was inhibited by methyl arachidonyl fluorophosphonate (MAFP), a cPLA(2) inhibitor. However, no change in activity of secretory PLA(2) or Ca(+2)-independent PLA(2) was observed in the TGF-alpha-stimulated cells. Stimulation with the Ca(2+) ionophore A23187 for 10 min induced MAFP-sensitive arachidonic acid liberation. Interestingly, preincubation with TGF-alpha for 24 h diminished A23187-stimulated arachidonic acid liberation despite the increase in cPLA(2) protein. Under the conditions, TGF-alpha was found to increase p11, an endogenous cPLA(2) suppressor, also known as annexin II light chain. The TGF-alpha-induced increase in p11 was suppressed by tyrphostin AG1478, an inhibitor of tyrosine kinase of epidermal growth factor receptor, which was also found to restore the inhibition by TGF-alpha of A23187-stimulated arachidonic acid liberation. However, TGF-alpha did not alter protein levels of annexin II heavy chain. These results suggest that TGF-alpha stimulates prostaglandin generation through an increase in cPLA(2), the hydrolytic action of which may be under the control of p11.

Animals↗
PubMed1999

Involvement of group VI Ca2+-independent phospholipase A2 in protein kinase C-dependent arachidonic acid liberation in zymosan-stimulated macrophage-like P388D1 cells.

We investigated the possible involvement of group VI Ca2+-independent phospholipase A2 (iPLA2) in arachidonic acid (AA) liberation in zymosan-stimulated macrophage-like P388D1 cells. Zymosan-induced AA liberation was markedly inhibited by methyl arachidonoyl fluorophosphonate, a dual inhibitor of group IV cytosolic phospholipase A2 (cPLA2) and iPLA2. We found that a relatively specific iPLA2 inhibitor, bromoenol lactone, significantly decreased the zymosan-induced AA liberation in parallel with the decrease in iPLA2 activity, without an effect on diacylglycerol formation. Consistent with this, attenuation of iPLA2 activity by a group VI iPLA2 antisense oligonucleotide resulted in a decrease in zymosan-induced prostaglandin D2 generation. These findings suggest that zymosan-induced AA liberation may be, at least in part, mediated by iPLA2. A protein kinase C (PKC) inhibitor diminished zymosan-induced AA liberation, while a PKC activator, phorbol 12-myristate 13-acetate (PMA), enhanced the liberation. Bromoenol lactone suppressed the PMA-enhanced AA liberation without any effect on PMA-induced PKC activation. Down-regulation of PKCalpha on prolonged exposure to PMA also decreased zymosan-induced AA liberation. Under these conditions, the remaining AA liberation was insensitive to bromoenol lactone. Furthermore, the PKC depletion suppressed increases in iPLA2 proteins and the activity in the membrane fraction of zymosan-stimulated cells. In contrast, the zymosan-induced increases in iPLA2 proteins and the activity in the fraction were facilitated by simultaneous addition of PMA. Although intracellular Ca2+ depletion prevented zymosan-induced AA liberation, the translocation of PKCalpha to membranes was also inhibited. Taken together, we propose that zymosan may stimulate iPLA2-mediated AA liberation, probably through a PKC-dependent mechanism.

Animals↗
PubMed1999

Stimulation by ceramide of phospholipase A2 activation through a mechanism related to the phospholipase C-initiated signaling pathway in rabbit platelets.

To study the involvement of sphingolipids in glycerophospholipid metabolism, the contribution of ceramide to the activation of group IV cytosolic phospholipase A2 (cPLA2) was investigated in platelets using cell-permeable C6-ceramide (N-hexanoylsphingosine). The addition of ceramide led to potentiation of thrombin-induced activation of cPLA2 and mitogen-activated protein kinase (MAPK) as well as arachidonic acid release and lysophosphatidylcholine formation. However, ceramide by itself did not induce any response. The arachidonic acid release due to the synergistic action of ceramide and thrombin was inhibited by PD98059, a MAPK kinase inhibitor. Ceramide also stimulated thrombin-induced protein kinase C (PKC) activation, but ceramide by itself failed to do so. Furthermore, ceramide synergistically enhanced diacylglycerol (DAG) formation and Ca2+ mobilization with thrombin, and also DAG formation with Ca2+-ionophore A23187. The DAG formation in response to ceramide with thrombin or A23187, as well as arachidonic acid release with thrombin were completely inhibited by U73122, a phospholipase C (PLC) inhibitor. These results suggest that ceramide triggers PLC activation through its synergistic action with thrombin, and subsequently potentiates the sequential PKC-MAPK cascade-cPLA2 pathway, thus resulting in enhancement of arachidonic acid release.

Animals↗
PubMed1999

Ceramide enhances susceptibility of membrane phospholipids to phospholipase A2 through modification of lipid organization in platelet membranes.

The effects of ceramide on agonist-stimulated phospholipase A2 (PLA2) activity were studied in platelets. Cell-permeable C6-ceramide (N-hexanoylsphingosine) exogenously added to platelet suspension enhanced U46619-stimulated arachidonic acid release and lysophosphatidylcholine production. Treatment of platelets with sphingomyelinase also led to an enhancement of the release. The enhanced arachidonic acid release by exogenous ceramide was completely inhibited by methyl arachidonyl fluorophosphonate, a cytosolic PLA2 inhibitor. However, U46619-stimulated PLA2 activity was not significantly potentiated by ceramide. These results suggest that enrichment of ceramide in membranes causes modification of intermolecular organization, leading to increased susceptibility of substrate phospholipids to PLA2.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1999

[Development of professional competence in public health nurses].

PURPOSE: Significant changes that are occurring in the community health care system, require that public health nurses who work for local governments to not only provide direct care but also to coordinate health care teams and participate in policy making. The purpose of this study is to investigate the current system of developing professional competence in public health nurses, and to consider ways to improve it. METHOD: The subjects, randomly chosen, were 100 chief public health nurses and 298 staff nurses in Hokkaido. Sixty-four chief nurses, 44 beginner nurses, 87 proficient nurses and 88 expert nurses responded. The data were collected with a self-administered questionnaire which necessitated the subjects to make a self evaluation of their practical competence and circumstances of its development. RESULT: Self evaluated competence, in making accurate assessments of individual needs and initiating direct care, developed with their experiences in the job, and was generally high. However, the questionnaire showed that self evaluation of their work and ability to do theoretical analysis and research was low and did not progress in conjunction with the length of work experience. Policy making experience was limited and policy making competence was evaluated as low, but there was an expectation that this competence would develop in time. Almost all of the respondents expected their professional competence to progress to higher levels. In particular, beginner nurses wanted to gain practical care competence; proficient and expert nurses wanted to develop their powers of theoretical analysis and do more research, while chief nurses were keen to gain competence in the area of policy making. The respondents reported that they sometimes attended academic conferences, but hardly did any research. CONCLUSION: Low self-evaluation of public health nurses reflect a basic immaturity as a profession. They need to establish their profession and to increase their self-evaluated competencies as their careers develop. These findings showed the importance of establishing a system of continuing education that will cultivate competence in various aspects of their job and also motivate self study. These findings also reveal the importance of collaboration between the university as a vehicle for theoretical work and research and the work place as the embodiment of practical application.

Clinical Competence↗
PubMed1998

Inhibition of Ca2+-independent phospholipase A2 by bromoenol lactone attenuates prostaglandin generation induced by interleukin-1 beta and dibutyryl cAMP in rat mesangial cells.

Cytokine-induced prostaglandin generation in rat mesangial cells has been suggested to be dependent on the expression of secretory phospholipase A2 (sPLA2). In the present study, we investigated the possible involvement of Ca2+-independent phospholipase A2 (iPLA2) in the generation. The results showed that bromoenol lactone, a relatively selective iPLA2 inhibitor, significantly attenuated prostaglandin E2 generation induced by interleukin-1beta and dibutyryl cAMP in parallel with the inhibition of iPLA2 activity. However, the inhibitor did not affect sPLA2 release upon stimulation, activities of sPLA2 or cytosolic phospholipase A2, or Ca2+ ionophore-induced arachidonic acid liberation. These results suggest that prostaglandin E2 generation upon stimulation may be partially mediated by iPLA2 in addition to sPLA2.

Animals↗
PubMed1998

Differential expression of moesin in cells of hematopoietic lineage and lymphatic systems.

Moesin is a member of the ERM family consisting of ezrin, radixin, and moesin. The protein is located in the plasma membrane similarly to ezrin and radixin, and is thought to regulate cellular movements and morphological changes. Using monoclonal antibody CR-22, the specificity of which against human moesin was confirmed by immunoprecipitation and western blotting analysis, we immunohistochemically stained various formalin-fixed and paraffin-embedded human tissues, in particular, clots of bone marrow and lymphatic tissues, to examine moesin expression in cells of hematopoietic lineage and lymphatic systems. In the bone marrow, moesin was expressed in myeloid cells, while little staining was detected in erythroid cells. Moesin was highly expressed in both the center and the periphery of mature megakaryocytes. In the lymphatic tissues, moesin was strongly expressed by T-lymphocytes in the paracortex. In the mantle zone, the periphery of the germinal center, moesin was expressed by small lymphocytes which were identified as B-lymphocytes. Furthermore, in areas of inflammation, moesin was expressed in both the center and the periphery of neutrophils, whereas in some neutrophils in distant areas, moesin was localized at the cellular periphery. These results suggest that differential expression of moesin in these cells is involved in their morphology and specialized functions.

Antibodies, Monoclonal↗
PubMed1998

Helicobacter pylori infection produces reversible glycosylation changes to gastric mucins.

The protective ability of gastric mucins may depend largely on their oligosaccharide chains. We evaluated the effects of H. pylori infection on the glycosylation of gastric mucins. Gastric biopsy specimens from 20 H. pylori-infected patients before and after cure of the H. pylori infection and 8 normal uninfected volunteers were examined by immunostaining for simple mucin-type glycoproteins and blood-group-related antigens bearing type 1 chain backbone. The immunoreactivity in different gastric compartments was evaluated. Simple mucin-type glycoproteins and blood-group-related antigens were expressed in surface mucous cells. Simple mucin-type glycoproteins showed antrum-predominant expression in normal volunteers and were found in significantly fewer surface mucous cells in infected patients than in normal volunteers; their expression was restored after eradication of H. pylori. Sialyl Lewis(a) and Lewis(b) were expressed in fewer surface mucous cells after than before eradication. The patterns of glycosylation of gastric mucins vary in different gastric compartments and are reversibly altered by H. pylori infection. These alterations may affect the protective functions of gastric mucins.

Adult↗
PubMed1997

Stimulation of cytosolic phospholipase A2-catalyzed arachidonic acid liberation by low dose tert-butyl hydroperoxide without an influence on the enzyme activity in rabbit platelets.

The effect of lipid peroxide on the hydrolytic action of cytosolic phospholipase A2 (cPLA2) in rabbit platelets was investigated. Ionomycin-stimulated arachidonic acid liberation and lysophosphatidylcholine formation were significantly potentiated when platelets were pretreated with tert-butyl hydroperoxide (BHP) and FeSO4, and then washed. Under the conditions, oxidizing reagents did not enhance the increase in cPLA2 activity by ionomycin or the basal activity in unstimulated cells. Furthermore, the treatment of a platelet lysate with BHP and FeSO4 did not affect Ca(2+)-induced translocation of cPLA2 to the membranes. However, with a membrane fraction, arachidonic acid liberation catalyzed by the partially purified cPLA2 was synergistically enhanced by BHP and FeSO4. These results suggest that oxidative stress may potentiate the hydrolytic action of cPLA2 on membrane phospholipids without an influence on the processes leading to the enzyme activation.

Animals↗
PubMed1997

Lipid peroxide overcomes the inability of platelet secretory phospholipase A2 to hydrolyze membrane phospholipids in rabbit platelets.

The present study investigated the effect of lipid peroxide on the ability of group IIA secretory phospholipase A2 (IIAsPLA2) to hydrolyze platelet membrane phospholipids. The treatment of rabbit platelets with tert-butyl hydroperoxide (BHP) and FeSO4 generated malondialdehyde, an index of lipid peroxidation, and slightly induced arachidonic acid liberation and lysophosphatidylcholine formation. Further addition of IIAsPLA2 purified from rabbit platelets synergistically enhanced the liberation and the formation induced by the oxidizing reagents, although the enzyme alone did not. When the IIAsPLA2 was pretreated with heparin, the enhancement was not observed. The combination of IIAsPLA2 with linoleic acid hydroperoxide and FeSO4 also caused synergistic arachidonic acid liberation. Furthermore, IIAsPLA2 enhanced thromboxane B2 generation and platelet aggregation induced by BHP and FeSO4. The synergistic aggregation was sensitive to indomethacin. With a membrane fraction as a substrate, IIAsPLA2 caused arachidonic acid liberation, which was enhanced in the presence of BHP and FeSO4. These results suggest that modification of membrane phospholipids by oxidizing reagents increases the accessibility of the membrane to platelet IIAsPLA2, and sequential enhancement of arachidonic acid liberation may contribute to the propagation of oxidative stress-induced cellular injury.

Animals↗
PubMed1997

High glucose-induced cytosolic phospholipase A2 activation responsible for eicosanoid production in rat mesangial cells.

The stimulation of prostaglandin E2 (PGE2) production in mesangial cells exposed to a high glucose level was studied from the viewpoint of its implication in the glomerular hyperfiltration in diabetic nephropathy. The basal PGE2 synthesis apparently increased in the cells on incubation with a high glucose level (20 mM) for 3-6 h. Under these conditions, secretory phospholipase A2 activity was not detected in the incubation medium, but cytosolic phospholipase A2 (cPLA2) activity in the cells increased time-dependently up to 6 h, compared with that with a normal glucose level (5 mM). However, no difference in the cPLA2 protein content between the two glucose levels was observed on immunoblot analysis, suggesting that the increased cPLA2 activity under high glucose conditions is not due to stimulation of de novo synthesis. Stimulation with a calcium ionophore markedly enhanced arachidonic acid liberation and PGE2 production by cells exposed to the high glucose level. Furthermore, mitogen-activated protein kinase (MAPK) activity increased time-dependently under high glucose conditions, the rate of increase being consistent with those in cPLA2 activity and PGE2 production under the same conditions. These data suggest that glucose-induced cPLA2 activation through MAPK activation is responsible for the enhancement of PGE2 production in mesangial cells.

Animals↗
PubMed1995

Improved detection of medically important fungi by immunoperoxidase staining with polyclonal antibodies.

This study was performed to identify pathological fungi of eight species [Aspergillus fumigatus, Candida albicans, Torulopsis (Candida) glabrata, Cryptococcus neoformans, Fusarium anthophilum, Rhizopus oryzae, Sporothrix schenckii and Trichosporon beigelii] in formalin-fixed, paraffin-embedded tissue sections by indirect immunoperoxidase staining. Mature albino rabbits were immunized with formalin-killed organisms. Antibodies were prepared by precipitation. Immunoperoxidase staining was applied to the paraffin-embedded tissue sections of experimentally infected mice and human autopsy and surgical specimens. Although the cell walls of each fungus stained clearly, many cross-reactivities appeared. However, it was possible to obtain specificity for the eight species by absorption and dilution of the antisera.

Animals↗
PubMed1995

Expression of CA15-3 in renal cell carcinoma.

CA15-3 expression was analyzed in renal cell carcinoma (RCC) from the standpoint of the histogenesis of RCC. Tissue sections from surgical specimens of 12 cases of clear cell type RCC and from autopsy specimens of eight fetal kidneys were stained by an indirect immunoperoxidase method using DF-3. All the RCC cases stained positively for CA15-3, with 10 of the 12 cases showing strong, diffuse immunoreactivity on the cell membrane. Expression of CA15-3, as well as other markers such as epithelial membrane antigen, neuron-specific enolase, glandular cytokeratin and other lectins, suggest a more complicated histogenesis of RCC, rather than a simple proximal tubular origin.

Carcinoma, Renal Cell↗
PubMed1993

Proliferative activity of hepatocytes in chronic viral hepatitis as revealed by immunohistochemistry for proliferating cell nuclear antigen.

Liver biopsy specimens of 65 cases of chronic viral hepatitis, including 29 cases of type B, 34 cases of type C, and two cases of non-A, non-B, non-C type, were immunohistochemically stained for proliferating cell nuclear antigen (PCNA) to evaluate the proliferative activity of hepatocytes. According to a histopathologic evaluation using the histology activity index (HAI) scoring system, chronic persistent hepatitis and chronic active hepatitis were clearly differentiated with no overlapping of the score. The labeling indices of PCNA of hepatocytes in chronic persistent hepatitis had a significant relationship with HAI scores (r = .54), suggestive of a contribution of lobular hepatocyte necrosis and/or portal inflammation to the regenerative rate of hepatocytes, but did not exceed 3.0%. On the other hand, 11 of 47 cases of chronic active hepatitis showed PCNA labeling indices higher than 3.5% without any significant relationship with the HAI scores. There was no significant difference, however, of distribution of HAI scores or PCNA labeling indices between hepatitis types B and C. Based on current concepts of the role of hepatocyte proliferation in the development of liver cirrhosis and hepatocellular carcinoma, the present results suggest that the high proliferative rate of hepatocytes subject to the persistent liver cell injury in chronic active hepatitis may be related to a reconstruction pattern of the liver in cases of progression to cirrhosis and development of hepatocellular carcinoma.

Biomarkers, Tumor↗
PubMed1988

The application of immunoperoxidase staining for the detection of causative fungi in tissue specimens of mycosis I.

This study was performed in order to identify the fungi of four species (Aspergillus fumigatus, Fusarium anthophilum, Candida albicans, Cryptococcus neoformans) in formalin-fixed, paraffin-embedded tissue sections by the indirect method of immunoperoxidase staining. Mature albino rabbits were immunized by formalin-killed organisms. The antibodies were prepared by precipitation at a 50% saturation of ammonium sulfate and were checked for cross-reactivities by Ouchterlony's double immunodiffusion and precipitin test. The immunoperoxidase staining was applied to the paraffin-embedded tissue sections of infected mice, human autopsy and biopsy specimens. Although each fungus was stained clearly the cell wall, cross-reactivities appeared among them, however it was possible to identify four fungi by absorption and dilution of the antisera.

Animals↗
PubMed1987

A combined stain for identifying epithelial cells of the gastric mucosa.

New techniques are proposed for differentiating each type of gastric epithelial cell in the same tissue section. The techniques combine the following stains: paradoxical concanavalin A staining (PCS) to identify mucous neck cells, periodic acid Schiff-concanavalin A staining to distinguish mucous neck cells from surface mucous cells, and a modified Bowie's stain to demonstrate zymogen granules of chief cells. Feulgen hydrolysis preceding the Bowie stain was found to remove most of the nonspecific coloration encountered with the original Bowie method. The results obtained by the new sequences were as follows: Feulgen hydrolysis-PCS-Bowie staining: mucous neck cells stained brown and chief cell zymogen granules deep blue. The other mucin-secreting cells remained unstained; Feulgen hydrolysis-PAS-concanavalin A-Bowie staining: mucous neck cells stained brown, zymogen granules stained deep blue to purplish blue and surface mucous cells stained purplish red.

Adult↗