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Biomedical subjects

H Sawa

Publications and source records attributed to H Sawa.

At least 109 records · Page 6Linked to original sources
PubMed1996

Expression of beta 1 integrins in human endometrial stromal and decidual cells.

The present study was undertaken to investigate the expression of beta1 integrins in human endometrium and decidua using flow cytometry, immunohistochemistry, and immunoprecipitation. Fluorescence-activated flow cytometry demonstrated the greater expression of the beta 1, alpha 1, alpha 2, and alpha 5 subunits of the beta1 integrin family in cultured stromal cells from the midsecretory phase, than in those of the early proliferative phase. The addition of estradiol (E2) and progesterone (P) to cultured stromal cells in the early proliferative phase increased the expression of beta1 integrins in vitro. The immunohistochemical distribution of beta1 integrins demonstrated predominantly glandular epithelial staining in the proliferative phase, and mesenchymal and glandular staining in the midsecretory phase. Flow cytometry also demonstrated the expression of the beta 1, alpha 1, alpha 2, alpha 3, alpha 5, and alpha 6 subunits of beta 1 integrin family in cultured decidual cells, and the enriched-fraction of prolactin (PRL)-producing decidual cells isolated by Percoll gradients showed high levels of beta 1, integrins expression. Immunohistochemistry confirmed the beta 1 integrin cell surface phenotypes in cultured decidual cells observed by flow cytometry. Autoradiography of immunoprecipitate subjects to SDS-PAGE revealed three major polypeptides with molecular weights of 130 kDa (beta 1 subunit), 165 kDa (alpha 2 subunit), and 210 kDa (alpha 1 subunit) under reducing conditions. In summary, the present study demonstrated that endometrial stromal and decidual cells expressed beta1 integrin subunits at their surfaces. The expression exhibited a variability throughout the menstrual cycles, being predominantly detected in the secretory phase, and was maintained highly in the decidua. Thus, beta 1 integrins in human endometrium and decidua may be important in mediating the organization of extracellular matrix proteins derived from embryos during the early stage of implantation.

Abortion, Therapeutic↗
PubMed1996

Growth and immunogenicity of human glioma in severe combined immunodeficiency-human mice.

The severe combined immunodeficiency (SCID) mouse was investigated as a model system to study the growth and immunogenicity of human gliomas. Human glioma cell lines U-251MG, KNS-42, SF-188, A-172, and T-98G were injected subcutaneously into SCID mice. The cell lines U-251MG and KNS-42 grew as large, subcutaneous masses; SF-188, A-172, and T-98G did not grow. Glioma-immune system interactions were studied by the transplantation of human peripheral blood lymphocytes into tumor-bearing SCID mice. In the resultant SCID-human (SCID-hu) mice, transplanted lymphocytes infiltrated into the subcutaneously growing tumors and expressed the surface markers of human B, T, and natural killer cells. The SCID-hu mouse is a potentially powerful model to study the basic tumor biology of some human gliomas and also represents a useful screening system to evaluate experimental immunotherapies for brain tumors.

Animals↗
PubMed1996

Functional analysis of trk proto-oncogene product in medulloblastoma cells.

MED-L cells with the 75 kd low-affinity nerve growth factor receptor (p75NGFR) and MED-H cells with the proto-oncogene tropomyosin receptor kinase product (p140trk) were isolated selectively from a parent MED-3 cell line derived from cerebellar medulloblastoma by panning, and the interaction of nerve growth factor (NGF) with these cell lines was analyzed. NGF treatment induced neuronal differentiation, growth inhibition, and tyrosine phosphorylation of p140trk in MED-H cells, but not in MED-L cells. Medulloblastoma cells express the functional NGFR, p140trk, which regulates their differentiation and growth.

Blotting, Northern↗
PubMed1996

[Questionnaire survey of AIDS examination recipients at government-run public health center regarding AIDS awareness promotion and HIV examinations].

An anonymous questionnaire survey was conducted among persons who had undergone screening for AIDS at public health centers under the auspices of 7 local government bodies (Hokkaido, Metropolitan Tokyo, Aichi Prefecture, Osaka Prefecture, Kobe City, Saga Prefecture, Okinawa Prefecture). There were 1,230 replies, for a response rate of 46.8%. Questions in the survey pertained to general knowledge of AIDS, information desired by the recipients, desired ways to foster awareness, and a desirable examination system. A comparison was made in terms of gender, marriage status (married, single) and age (less than 40 years of age, more than 40 years of age), respectively. The survey results were as follows. 1. Concerning the infection route, accurate response rate was low with regard to the mother-child infection, mosquito transmission, and use of contaminated needles. 2. Desired methods to promote AIDS awareness expressed among replies were given in the following order or frequency: "information via radio and TV," "spread of knowledge through telephone consultation," and "holding an AIDS Week or similar kinds of campaigns." 3. Information sought by respondents frequently included AIDS treatment, pathology, and spread. This trend was most obvious among those under 40 years of age. 4. As for the AIDS examination system, replies most often reflected the hope that the examination site would be the Public Health Center, the charge would be gratis, and that one could be examined at night during the week, and on days off. 5. For those undergoing examination where there was no actual concern of possibility of HIV infection, single persons, accounted for around 80% of the overall. 6. More than half of those who had been examined mentioned having experienced concerns about maintaining confidentiality at the time they were examined.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Massive cell death of immature hematopoietic cells and neurons in Bcl-x-deficient mice.

bcl-x is a member of the bcl-2 gene family, which may regulate programmed cell death. Mice were generated that lacked Bcl-x. The Bcl-x-deficient mice died around embryonic day 13. Extensive apoptotic cell death was evident in postmitotic immature neurons of the developing brain, spinal cord, and dorsal root ganglia. Hematopoietic cells in the liver were also apoptotic. Analyses of bcl-x double-knockout chimeric mice showed that the maturation of Bcl-x-deficient lymphocytes was diminished. The life-span of immature lymphocytes, but not mature lymphocytes, was shortened. Thus, Bcl-x functions to support the viability of immature cells during the development of the nervous and hematopoietic systems.

Animals↗
PubMed1995

Induction of plasminogen activator inhibitor type-1 (PAI-1) by proinsulin and insulin in vivo.

BACKGROUND: Fasting hyperinsulinemia (reflected by elevations in immunoreactive "insulin") is typical of patients with non-insulin-dependent diabetes mellitus (NIDDM) and is often associated with obesity and hypertension. The elevated concentrations detected are indicative not only of insulin but also of its immunologically cross-reactive precursors, including proinsulin. Fasting hyperinsulinemia appears to be associated with decreased fibrinolytic activity in blood, which results from increased activity of plasminogen activator inhibitor type-1 (PAI-1), a potential independent risk factor for coronary artery disease. Patients who were given proinsulin in a previous clinical study by others exhibited an increased incidence of cardiovascular events. Thus, a "proinsulin-PAI-1 axis" may predispose to coronary thrombosis. To define the possible presence of such an axis, this study was designed to determine whether insulin, its precursors, or both increase the concentrations of PAI-1 in rabbits in vivo. METHODS AND RESULTS: Equimolar proinsulin (n = 10), insulin (n = 11), C-peptide (n = 4), or vehicle alone (n = 10) was administered intravenously over 1 hour to euglycemic, conscious rabbits. Plasma PAI-1 activity increased 3.8-fold with proinsulin (P = .002) and 3.6-fold with insulin (P = .002). By contrast, no increase occurred after C-peptide or vehicle was administered. The increased PAI-1 activity was shown to be attributable to PAI-1 protein by reverse fibrin autography. As judged from changes in mRNA in tissues, proinsulin and insulin increased PAI-1 gene expression within 3 hours by 2.1- and 2.1-fold, respectively, in aorta (P = .025 each) and by 1.9- and 2.4-fold in liver (P = .015 and P = .001), with return of values to baseline within 24 hours (n = 4 experiments in each case). CONCLUSIONS: These results extend our previous observations from studies in vitro and suggest that hyperinsulinemia attributable to augmented concentrations of proinsulin and insulin in plasma increase plasma PAI-1 activity and may contribute to acceleration of atherosclerosis and impairment of coronary thrombolysis in patients with NIDDM.

Animals↗
PubMed1995

Expression of renin and angiotensin-converting enzyme in human hearts.

To understand the significance of the tissue renin-angiotensin system in the heart, we examined the expression of renin and angiotensin-converting enzyme (ACE) in autopsied human hearts. Samples were taken from organs obtained at autopsy from 15 patients without heart disease and 3 patients with heart disease (old myocardial infarctions, acute myocardial infarctions, and hypertrophic cardiomyopathy). We examined the expression of renin and ACE mRNA by using the reverse transcription-polymerase chain reaction (RT-PCR). RT-PCR showed the expression of renin in the right atria in all patients. However, expression of renin mRNA in the left ventricles was not found in any of the 15 hearts without heart disease. In contrast, renin mRNA was detected in the left ventricles in hearts with heart disease. ACE mRNA was detected in both the atria and the ventricles in normal hearts, and its expression did not alter in diseased hearts. These findings suggest that renin mRNA is expressed mainly in the right atria in normal hearts, but that its expression in the left ventricle can be activated in some pathological conditions.

Adult↗
PubMed1995

Glucose transporter expression and functional role of hexokinase in insulin biosynthesis in mouse beta TC3 cells.

It was previously reported that insulin biosynthesis in mouse beta TC3 cells was regulated by glucose (Nagamatsu, S., and D. F. Steiner. Endocrinology 130: 748-754, 1992). In the present study, we examined the effect of glucose on the glucose transporter expression and hexokinase activities and determined the relationship between them and glucose-stimulated insulin biosynthesis in beta TC3 cells. Reverse transcriptase-polymerase chain reaction and Northern blot analysis revealed that beta TC3 cells expressed GLUT-1 and GLUT-3 glucose transporter mRNAs, but not GLUT-2. The levels of GLUT-1 and GLUT-3 mRNAs were not affected by glucose (0 or 11 mM glucose) over a period of 48 h. Immunoprecipitation of metabolically labeled beta TC3 cells with specific antibodies against GLUT-1 or GLUT-3 proteins revealed no effect of glucose on the biosynthesis of glucose transporters. Hexokinase [low Michaelis constant (Km) hexokinase] activity from cells incubated in 11 mM glucose for 48 h increased nearly twofold compared with cells maintained in 0 mM glucose, although the amount of cellular hexokinase protein detected by immunoblot analysis was unchanged between 0 and 11 mM glucose conditions. Glucokinase (high Km hexokinase) activity, in contrast, was not affected by glucose. Preincubation of beta TC3 cells with 2-deoxyglucose to inhibit hexokinase, thereby inhibiting all glycolysis, resulted in the decrease of glucose-stimulated insulin biosynthesis. Thus, in mouse beta TC3 cells that do not express GLUT-2, there is a close relationship between hexokinase activity and glucose-stimulated insulin biosynthesis, but not between the glucose transporter and glucose-stimulated insulin biosynthesis.

Animals↗
PubMed1995

Effects of beta-1 integrins in the process of implantation.

The expression and function of beta 1 integrins on human decidual cells were investigated. Flow cytometric analysis revealed that the cultured decidual cells expressed a high level of the beta 1 subunit on the cell surface. Mouse blastocysts attached to and spread onto cultured human decidual cells. Attachment of the blastocysts was a necessary prerequisite for the further outgrowth of trophoblasts. The addition of a monoclonal antibody recognizing the beta 1 subunit to the cultured decidual cells did not affect the rates of hatching and attachment of blastocysts. The outgrowth of embryos on decidual cells was inhibited by the addition of the anti-beta 1-subunit antibody in a dose-dependent manner. Furthermore, exposure of decidual cells to the anti-beta 1-subunit antibody significantly inhibited the extent of outgrowth of trophoblasts, implying that blastocyst attachment and outgrowth is mediated by different mechanisms. These observations suggest that beta 1 integrins on decidual cells may be involved in the process of blastocyst development and differentiation after attachment.

Antibodies, Monoclonal↗
PubMed1995

Localization of apoptotic cells in situ of brain tumors.

The apoptotic cells in situ of normal tissues and human brain tumors were analyzed by the modified method of TUNEL, and the relationship between the localization of apoptotic cells and the expression of bcl-2 protein was examined. The localization of apoptotic cells in normal tissue was situated at fast renewing tissues, and differed from the localization of the expression of bcl-2 protein. In the cases of medulloblastoma, 7 out of 8 cases (87.5%) showed apoptotic cells. In contrast to the results of high frequency of apoptotic cells in medulloblastoma and germinoma, the expression of bcl-2 protein was found very low incidence in those tumors, which were thought to be sensitive against radiation or chemotherapy. These results suggested that the detection of apoptosis in situ by this method could predict the sensitivity of radiation or chemotherapy of the tumor cells.

Animals↗
PubMed1994

Developmental expression of GLUT3 glucose transporter in the rat brain.

The ontogeny of the GLUT3 glucose transporter gene and protein expression was studied in rat brain. Northern blot analysis using total RNA from rat brains at different developmental stages revealed that the levels of GLUT3 mRNA were very low during the embryonic stage and increased towards the postnatal stage. Immunohistochemistry using a specific antibody showed that the expression of GLUT3 protein was barely detectable in the embryonic stage, but was clearly detected on the plasma membrane of neuronal cells from 10 days after birth to the adult. Expression of GLUT3 mRNA and protein in the cerebral neuronal cell cultures was also examined during the maturation of neurons. GLUT3 glucose transporter of primary neuronal cultured cerebral cortical neurons was only detected in mature neurons after they were cultured for 14 days. These results indicate that GLUT3 plays an important role in glucose homeostasis postnatally in neurons of the rat brain.

Amino Acid Sequence↗
PubMed1994

Gene expression of GLUT3 glucose transporter regulated by glucose in vivo in mouse brain and in vitro in neuronal cell cultures from rat embryos.

This study was designed to determine whether glucose regulates the gene expression of glucose transporter GLUT3 in neurons. We examined the regulation of GLUT3 mRNA by glucose in vivo in mouse brain and in vitro by using neuronal cultures from rat embryos. Hypoglycaemia (< 30 mg/dl), produced by 72 h of starvation, increased GLUT3 mRNA in mouse brain by 2-fold. Hybridization studies in situ demonstrated that hypoglycaemia-induced increases in GLUT3 mRNA expression were observed selectively in brain regions including the hippocampus, dentate gyrus, cerebral cortex and piriform cortex, but not the cerebellum. Primary neuronal cultures from rat embryos deprived of glucose for 48 h also showed an increase (4-fold over control) in GLUT3 mRNA, indicating that glucose can directly regulate expression of GLUT3 mRNA. In contrast with hypoglycaemia, hyperglycaemia produced by streptozotocin did not alter the expression of GLUT3 mRNA. We also confirmed previous findings that hypoglycaemia increases GLUT1 mRNA expression in brain. The increase in GLUT1 expression was probably limited to the blood-brain barrier in vivo, since GLUT1 mRNA could not be detected in neurons of the mouse cerebrum. Thus we conclude that up-regulation of neuronal GLUT3 in response to glucose starvation represents a protective mechanism against energy depletion in neurons.

Animals↗
PubMed1994

Inhibition of type-1 plasminogen activator inhibitor production by antisense oligonucleotides in human vascular endothelial and smooth muscle cells.

We have hypothesized that type-1 plasminogen activator inhibitor (PAI-1) may exacerbate accumulation of extracellular matrix in atheroma by inhibiting local generation of plasmin and intramural proteolysis. Thus, suppression of PAI-1 expression would decrease atherogenesis. To inhibit expression of PAI-1 in cultured human umbilical vein endothelial and aortic smooth muscle cells, a 20-base antisense phosphorothioate oligonucleotide targeting specific sequences in the 3'-untranslated region of the PAI-1 gene was used. Studies with 32P-labeled oligomers verified stability in media. Secretion of PAI-1 protein assayed by enzyme-linked immunosorbent assay declined specifically and dose-dependently in cells exposed to the antisense oligonucleotide treated under basal conditions and after stimulation of PAI-1 expression with transforming growth factor beta (0.5 ng/ml for endothelial cell, 5 ng/ml for smooth muscle cell). Inhibition of expression was confirmed by immunoprecipitation of 35S-labeled PAI-1 and was paralleled by decreased steady-state levels of PAI-1 mRNA (Northern blots). Decreased PAI-1 synthesis was accompanied by augmentation of cell-associated plasmin activity. Thus, the antisense oligonucleotide down-regulated PAI-1 elaboration, an approach that may be useful in limiting obstructive vascular lesions.

Base Sequence↗
PubMed1994

Targeted disruption of Bcl-2 alpha beta in mice: occurrence of gray hair, polycystic kidney disease, and lymphocytopenia.

Mice carrying ablated coding regions of the bcl-2 alpha and bcl-2 beta transcripts have been made. bcl-2-/- mutants are smaller but viable, although about half of them die by 6 weeks of age. As shown earlier with somatic bcl-2 gene-targeted mice, the number of lymphocytes markedly decreased within few weeks after birth while other hematopoietic lineages remained unaffected. Among lymphocytes, CD8+ T cells disappeared most quickly followed by CD4+ T cells, whereas B cells were least affected. bcl-2-/- lymphocytes, however, could respond normally to various stimuli including anti-CD3, Con A, phorbol 12-myristate 13-acetate plus ionomycin, interleukin 2, lipopolysaccharide, and anti-IgM antibody. Abnormalities among nonlymphoid organs include smaller auricles, hair color turning gray at 4-5 weeks of age, and polycystic kidney disease-like change of renal tubules. These results suggest that Bcl-2 may be involved during morphogenesis where inductive interactions between epithelium and mesenchyme are important such as in the kidneys, hair follicles, and perichondrium of auricles. Surprisingly, the nervous system, intestines, and skin appear normal despite the fact that these organs show high levels of endogenous Bcl-2 expression in normal mice.

Animals↗
PubMed1994

C-CAM expression in the developing rat central nervous system.

C-CAM, a transmembrane glycoprotein belonging to the immunoglobulin superfamily, can mediate intercellular adhesion by homophilic, Ca(2+)-independent binding. Immunohistochemical analysis of adult rat tissues has demonstrated that C-CAM is expressed in various epithelia, vessel endothelia, and hematopoietic cells. By molecular cloning and sequence analysis several isoforms differing both in the extracellular and the cytoplasmic domains have been found. Here we have analyzed the expression of C-CAM in the developing rat central nervous system. No neuronal expression was observed, but biochemical and immunohistochemical analyses demonstrated that C-CAM becomes expressed in the microvessels from embryonic day E-13; the intensity of the staining increased through day E-15 and then gradually decreased during the perinatal and early postnatal period. The expression of C-CAM in the walls of the microvessels was confirmed by in situ hybridization. Immunoelectron microscopy showed that C-CAM was localized both to the abluminal surface of the endothelial cells and to cellular processes of primordial pericytes where these two cell types are in contact with each other. No staining was found on the luminal endothelial cell surfaces or inter-endothelial cell contact areas. During the perinatal period C-CAM also became expressed on the opposite side of the pericytes and on other cells, possibly astrocytes, in contact with these areas of the pericytes. These observations suggest that C-CAM may be involved in heterotypic, homophilic adhesion between endothelial cells, pericytes and astrocytes, and in maturation of the vessel walls.

Adenosine Triphosphatases↗
PubMed1994

Distribution of angiotensinogen in diseased human hearts.

Extrahepatic synthesis and localization of angiotensinogen (ATN) have been described in animals, thus establishing the tissue renin-angiotensin (RA) system. However, there had been no reports of tissue RA systems in human organs, including the heart. In earlier, we have reported the possibility of ATN synthesis in the human heart using ribonuclease protection assay system. ATN mRNA was detected not only in the liver, but also in both the atrial and ventricular heart tissues, suggesting that ATN is synthesized in the human heart. In this report, we looked for the distribution of ATN in diseased human heart. Northern blot hybridization of cDNA with total RNA extracted from human liver, brain, kidney, atrial and ventricular tissues revealed that ATN mRNA exists in cardiac ventricule. Immunohistochemical studies using a specific antibody to ATN revealed a stronger reaction in the endocardial layer of the human left ventricle, than in the epicardial layer, and intense immunoreactivity in the conduction system and right atrium. This distribution pattern was similar to that of human atrial natriuretic peptide (hANP), which functions a smooth muscle relaxant. Double immunostaining of ATN and hANP demonstrated that all myocytes in the right atrium had immunopositive reactions to ATN, hANP or both of ATN and hANP. Double immunoelectron staining enabled us to show more detailed localization of ATN and hANP; hANP only existed in the specific granules and ATN existed in the myofibril, but not in the granule. Furthermore, our experiments provide evidence of ATN in healthy human hearts and also reveal a widespread immunopositive reaction for ATN in the left ventricle of diseased hearts.

Angiotensinogen↗