Biomedical subjects

H Kawaguchi

Publications and source records attributed to H Kawaguchi.

At least 253 records · Page 14Linked to original sources

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↗

PubMed1994

Ultrastructural studies and immunolocalization of enamel proteins in rodent secretory stage ameloblasts processed by various cryofixation methods.

BACKGROUND: Cryofixation rapidly immobilizes cell and tissue components in their native state, thereby resulting in an ultrastructural preservation very close to the living situation. We have applied this approach to examine the morphology of secretory stage ameloblasts and the distribution of enamel proteins in these cells. METHODS: Molar and incisor tooth germs from newborn mice and/or rats were quickly dissected and divided into segments. The segments were then rapidly frozen using slam, plunge or pressure freezing, freeze-substituted and embedded in Epon. In addition, incisors from older rats were chemically fixed by vascular perfusion and also dehydrated by freeze-substitution. RESULTS: Well-preserved ameloblasts were obtained with all four tissue processing methods. However, slam freezing often showed mechanical damage to the ameloblasts, particularly at the level of the distal portion of Tomes' processes which appeared severed or distorted. Plunging into liquid nitrogen-cooled liquid propane resulted in comparatively less tissue distortion. High pressure freezing gave a relatively higher yield of well-preserved specimens, although displacement of organelles in ameloblasts was sometimes observed, probably resulting from hydrostatic pressure. Minimal ice crystal and mechanical damage was observed in chemically fixed tooth samples processed by freeze-substitution since such specimens are cryoprotected and their examination is not restricted to a surface layer. With all of the above cryopreparation methods, the ultrastructure of well-preserved ameloblasts was, in general, similar to that obtained following conventional chemical fixation, and immunocytochemistry with an anti-amelogenin antibody indicated no profound differences in the distribution of enamel proteins. CONCLUSIONS: These results indicate that, despite some limitations, it is possible to adequately cryofix tooth organs while preserving the architecture of ameloblasts and permitting immunolocalization of enamel proteins. Furthermore, they confirm the general morphology of secretory stage ameloblasts as currently derived from conventional chemical tissue processing.

Ameloblasts↗

PubMed1994

Activation of human neutrophils by Arg-Gly-Asp-Ser immobilized on microspheres.

The adhesive interaction of cells with extracellular matrix components is essential for a variety of cellular functions, and is frequently mediated by a tetra peptide, Arg-Gly-Asp-Ser (RGDS), located within fibronectin and other proteins. In this study, the RGDS-mediated activation of polymorphonuclear leukocytes accompanied by phagocytosis was investigated using monodisperse polymeric microspheres carrying RGDS. The parent and Arg-Gly-Glu-Ser (RGES)-carrying microspheres, which have no adhesion activity, were employed as controls. The ingestion of microspheres into PMN was not enhanced by immobilizing RGDS. However, PMNs exhibited unique oxygen consumption and enhanced liberation of reactive oxygen when RGDS-carrying microspheres were phagocytosed. These PMN responses disappeared with the addition of soluble RGDS. Furthermore, cytochalasin D, which inhibits actin polymerization, showed a marked inhibitory effect on oxygen consumption in the RGDS-carrying microsphere system, as compared with those in other systems. These findings show that RGDS-carrying microspheres induced the biospecific activation of PMNs by the signal transduction via RGDS-integrin binding without alteration in the degree of phagocytosis.

Amino Acid Sequence↗

PubMed1994

Comparison of the effects of 3,5,3'-triiodothyroacetic acid and triiodothyronine on bone resorption in cultured fetal rat long bones and neonatal mouse calvariae.

Thyroid hormones can stimulate bone resorption both directly and indirectly by increasing endogenous prostaglandin (PG) synthesis. Because 3,5,3'-triiodothyroacetic acid (Triac, Tiratricol) can bind to nuclear thyroid hormone receptors with high affinity, we compared the effects of Triac and 3,5,3'-triiodothyronine (T3) on bone resorption. 45Ca release was measured at 2, 5, and 8 days from 19-day-old-fetal rat long bones in the presence or absence of calcitonin, indomethacin, aphidicolin (APC), cortisol, or interleukin-1 receptor antagonist (IL-1ra). Both Triac and T3 stimulated 45Ca release in a dose-dependent manner. The maximal treated/control ratio (T/C) for Triac (10(-7) M) was 1.6 +/- 0.1 at 2 days and 2.5 +/- 0.1 at 5 days and, for T3 (10(-7) M), 1.5 +/- 0.1 at 2 days and 2.6 +/- 0.1 at 5 days. These responses were smaller and slower than that to PTH. Significant stimulation of resorption was observed at 10(-8), 10(-9), and 10(-10) M for Triac but only at 10(-8) and 10(-9) M for T3. Indomethacin (10(-6) M) and IL-1ra (1 microgram/ml) did not decrease the effects of Triac or T3. In contrast, calcitonin (10(-9) M), APC (30 microM), and cortisol could all block the response to these hormones. These results indicated that the resorptive responses were not mediated by endogenous PG or IL-1 but were osteoclast mediated and dependent on DNA synthesis, suggesting that these hormones acted by stimulating replication of osteoclast precursors or other supporting cells. Thyroid hormones were less effective in 7-day-old neonatal mouse calvariae.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Stimulation of prostaglandin E2 production by interleukin-1 alpha and transforming growth factor alpha in osteoblastic MC3T3-E1 cells.

The mechanism by which interleukin-1 (IL-1) and transforming growth factor alpha (TGF-alpha) regulate prostaglandin synthesis has been examined in the clonal mouse osteoblastic cell line MC3T3-E1. Cells were grown in DMEM containing 10% fetal calf serum. Prostaglandin E2 (PGE2) production was determined by radioimmunoassay or by prelabeling cells with [3H]arachidonic acid, followed by high-performance liquid chromatography (HPLC) analysis of the labeled products released into the medium. Prostaglandin G/H synthase (PGHS) mRNAs were quantified by northern blot analysis using [32P]labeled cDNA probes. By HPLC, PGE2 was the major prostanoid produced under basal or stimulated conditions. No release of thromboxane or 6-keto-PGF1 alpha into the medium was detected. PGE2 production was stimulated approximately 7- to 14-fold by IL-1 (1 ng/ml) and 3- to 8-fold by TGF-alpha (30 ng/ml) after 24 h. In combination, however, IL-1 and TGF-alpha caused a synergistic 37- to 71-fold increase in PGE2 accumulation. PGHS-1 mRNA levels were maximally increased approximately 2- to 3-fold by IL-1 and 1.5 to 2.5-fold by TGF-alpha after 24 h; the combination of IL-1 and TGF-alpha produced only an additive 3- to 6-fold increase. Western blotting revealed a corresponding 3-fold increase in immunoreactive PGHS-1 protein in response to combined IL-1 and TGF-alpha. PGHS-2 mRNA was increased 1.4-fold by TGF-alpha at 1 h, and the combination of IL-1 and TGF-alpha caused a 1.7-fold increase.(ABSTRACT TRUNCATED AT 250 WORDS)

3T3 Cells↗

PubMed1994

Stimulatory effect of a phorbol ester on expression of insulin-like growth factor (IGF) binding protein-2 and level of IGF-I receptors in mouse osteoblastic MC3T3-E1 cells.

We examined the relationship between signal transduction and the expression of insulin-like growth factor I (IGF-I), IGF-I receptor level, and IGF binding proteins (IGFBPs) in murine clonal osteoblastic MC3T3-E1 cells. 12-O-Tetradecanoylphorbol-13-acetate (TPA), an activator of protein kinase C, decreased the secretion of immunoreactive IGF-I into the medium, whereas dibutyryl cAMP (Bt2cAMP) augmented the secretion. In contrast, TPA increased the level of type I IGF receptor on the cells. Furthermore, MC3T3-E1 cells produced and secreted at least three different IGFBPs with molecular masses of 24, 30, and 34 kDa, and the 24-kDa IGFBP was predominant under normal conditions. However, TPA specifically increased the secretion of the 34-kDa IGFBP. The N-terminal amino acid sequence of the purified 34-kDa IGFBP was nearly identical with that of rat IGFBP-2. Furthermore, the 34-kDa IGFBP was immunoreactive to anti-IGFBP-2 antiserum. The level of IGFBP-2 mRNA in the cells was increased by TPA, indicating that the increase in IGFBP-2 secretion results from the stimulation of IGFBP-2 production. In contrast, Bt2cAMP affected neither IGF-I receptor number nor the IGFBP secretion. These results indicate that the production of IGF-I and the expression of IGF-I receptors and IGFBP-2 are up-regulated by the activation of adenylate cyclase and protein kinase C, respectively, in osteoblastic MC3T3-E1 cells.

Adenylyl Cyclases↗

PubMed1994

Microdynamics of the phospholipid bilayer in cardiomyopathic hamster heart cell membrane.

To investigate the microdynamics and the structural architecture of the membrane phospholipid bilayer during the course of cardiomyopathy, membrane fractions were prepared from hearts of cardiomyopathic Syrian hamsters (BIO 14.6) aged 4, 18 and 31 weeks and compared with age-matched control hamsters (F1b). Membrane cholesterol, phospholipids and phospholipid fatty acids were measured by thin-layer chromatography, gas-liquid chromatography and high performance liquid chromatography. Microdynamics of the phospholipid bilayer were determined by a nanosecond fluorometer using pulsed excitation of a fluorescent probe, diphenyl-hexatriene. At the age of 4 weeks, there was no difference in lipid compositions and microdynamics between the BIO 14.6 and F1b. At the age of 18 weeks, saturated fatty acids, 18:0 and 22:0 increased and 20:0, 20:2 and 32:4 decreased in the BIO 14.6. At the age of 31 weeks, adding to the above changes in phospholipid fatty acids, unsaturated fatty acids 20:4 and 22:6 decreased, moreover membrane phospholipids, especially phosphatidylinositol and phosphatidylethanolamine significantly decreased. The viscosity and the wobbling angle of phospholipid molecules were decreased significantly. We have previously demonstrated that intracellular Ca2+ accumulation might be responsible for the pathogenesis of cardiomyopathy. Thus, we conclude that cardiomyopathic membrane may alter its structure and function with age. These alterations in cell membranes might be involved in the cardiac hypertrophy and dysfunction through impaired Ca2+ handling in cardiomyopathic hamsters.

Animals↗

PubMed1994

Transforming growth factor beta-1 modulates the number of beta-adrenergic receptors in cardiac fibroblasts.

The effects of transforming growth factor beta-1 on concentration of intracellular Ca2+ changes in the presence of isoproterenol were studied in cardiac fibroblasts. Transforming growth factor beta-1 effect on cyclic-AMP production and ligand assay of beta-adrenergic receptors were also examined. Production of cyclic-AMP in fibroblasts preincubated with transforming growth factor beta-1 decreased compared with non-transforming growth factor beta-1-treated fibroblasts in the presence of isoproterenol. An increase of intracellular Ca2+ concentration in the presence of isoproterenol was also inhibited in transforming growth factor beta-1-treated fibroblasts. Islet-activating protein did not restore these reactions of transforming growth factor beta-1. Concentration change of intracellular calcium under the treatment of transforming growth factor beta-1 was unaffected by forskolin addition. Binding of [3H]CGP-12177 was decreased to 47% of control preincubated for 24 h with transforming growth factor beta-1 in fibroblasts. Scatchard plots suggested a decrease in beta-adrenergic receptor number without specific change in receptor affinity. These results suggested that transforming growth factor beta-1 modulates the signal transduction through beta-adrenergic receptor and intracellular Ca2+ concentration by regulating the number of receptor in fibroblasts.

Animals↗

PubMed1994

Ultrastructure of guinea pig stria vascularis processed by rapid freezing and freeze substitution.

The rapid-freezing and freeze-substitution method fixes a specimen as if it were prepared before excision. We used this method to study the stria vascularis of guinea pigs using electron microscopy. Findings were essentially the same as those obtained with conventional chemical fixation, although freeze substitution made it possible to observe the membrane structures in a smoother and more linear manner. This method seems to be the procedure of choice for studying the instantaneous movement and behavior of cells.

Animals↗

PubMed1994

Ansa-recurrent nerve anastomosis for vocal cord paralysis due to mediastinal lesions.

Recurrent laryngeal or vagus nerve injuries in the mediastinum are repaired rarely because of technical difficulties. Impairment in phonation is especially severe in patients with respiratory dysfunction. We performed a simple and less invasive reconstruction, ansa cervicalis-recurrent laryngeal nerve anastomosis in the neck, to improve phonation in 2 patients. Although the reinnervated vocal cord did not regain normal movement, both of the patients obtained excellent improvement in phonation.

Aged↗

PubMed1994

Preparation and properties of A-B-A type block copolymer membranes consisting of poly(N-hydroxypropyl-L-glutamine) as the A component and polyisoprene as the B component.

A-B-A type block copolymer (GIG(P)) membranes consisting of poly(N-hydroxypropyl-L-glutamine) (PHPG) as the A component and polyisoprene (PI) as the B component were prepared by carrying out aminoalcoholysis reaction with 3'-amino-1-propanol and a crosslinking reaction with 1,8-octamethylenediamine (OMDA) on membranes of the starting block copolymer (GIG) membranes consisting of poly(gamma-benzyl L-glutamate) (PBLG) and PI. It was shown that the effective crosslink density was proportional to the molar % of OMDA in the reaction mixture. The relation between their bulk structure and membrane properties was investigated, such as the swelling ratio q in a pseudo-extracellular fluid (PECF), tensile properties, and enzymatic degradation behaviour of the membranes in PECF. The tensile properties of the hydrophilic membranes were highly dependent on q in PECF, and on the hydrophobic portions in molecular chains, whose behaviour was typical of an elastomer. Biodegradation of samples in vitro by papain indicated that the rate of degradation was also highly dependent on q of membranes in PECF.

Biocompatible Materials↗

PubMed1994

Influence of the structure of support microspheres on leucocyte activation by RGDS-carrying microspheres.

A cell adhesive peptide, Arg-Gly-Asp-Ser (RGDS), enhances leucocyte response to stimuli when insolubilized or conjugated with proteins. In order to investigate the contribution of the microsphere structure to leucocyte response. RGDS was immobilized onto several polymeric microspheres. The respiratory burst of polymorphonuclear leucocytes (PMNs) contacting contacting microspheres was enhanced by RGDS in cases where it was immobilized on polystyrene and, more effectively, a positively charged one. This was not observed in polyacrylamide-based or negative-charged microsphere systems. These results demonstrate that the property of supports strongly affects the regulation of the PMN response via an adhesive interaction.

Amino Acid Sequence↗

PubMed1994

Measurement of interleukin-1 stimulated constitutive prostaglandin G/H synthase (cyclooxygenase) mRNA levels in osteoblastic MC3T3-E1 cells using competitive reverse transcriptase polymerase chain reaction.

To assess regulation of constitutive prostaglandin G/H synthase (PGHS-1) by interleukin-1 (IL-1) in osteoblastic MC3T3-E1 cells, we compared analysis by competitive reverse transcriptase-polymerase chain reaction (RT-PCR) with Northern blot analysis. Using RT-PCR, IL-1 increased PGHS-1 mRNA levels by 1.84 +/- 0.10 or 2.07 +/- 0.17, depending on the method of calculation. Using Northern blot analysis, the effect of IL-1 on PGHS-1 mRNA levels was more variable, and the variability was increased by normalization of PGHS-1 mRNA levels to the housekeeping genes, beta-actin and glyceraldehyde phosphate dehydrogenase (GAPDH), because their mRNA levels were also regulated by IL-1. We conclude that competitive RT-PCR is a reproducible and accurate method for studying small changes in mRNA levels.

Animals↗

PubMed1994

Acute myocardial infarction due to thrombus formation in congenital coronary artery fistula.

A young female patient developed acute myocardial infarction during physical exercise. Coronary arteriography in the acute phase demonstrated a coronary fistula originating from the left coronary main trunk and communicating with the right atrium. Several branches of the left coronary artery were obstructed by thrombotic material originating from the fistula, causing an acute myocardial infarction.

Adolescent↗

PubMed1994

Relationship between Helicobacter pylori infection and gastric acid secretion in young healthy subjects.

We studied the relationship between Helicobacter pylori (H. pylori) infection and gastric acid secretion, along with fasting serum gastrin levels, in 55 asymptomatic healthy volunteers under 30 years old (29 H. pylori-positive, 26 H. pylori-negative). Mean scores of antral gastritis were significantly higher in H. pylori-positive subjects than in H. pylori-negative subjects. There was no significant difference in both basal and maximal acid output between H. pylori-positive and H. pylori-negative subjects. Fasting serum gastrin levels were significantly higher in H. pylori-positive subjects than in H. pylori-negative subjects. Sex did not significantly affect gastritis scores, gastric acid secretion, or fasting serum gastrin levels, although maximal acid output was slightly higher in H. pylori-negative men than in H. pylori-positive men. Our results suggest that H. pylori infection has no direct effect on gastric acid secretion in young healthy subjects, although it induces hypergastrinemia.

Adult↗

PubMed1994

Acute heart failure and acute renal failure in Kawasaki disease.

Acute renal failure and acute heart failure are rare in Kawasaki disease. We experienced two patients with Kawasaki disease who presented acute renal failure and acute heart failure. These two patients gave us an important insight into the understanding of water balance and fluid therapy in Kawasaki disease. One patients showed acute prerenal failure due to fluid exudation from the intravascular to the extravascular space, and subsequent acute heart failure. The other patient showed acute heart failure caused by fluid infusion for the treatment of dehydration. It is suggested that acute renal failure could be caused by a fluid shift from the intravascular to the extravascular space in Kawasaki disease. It is also demonstrated that the reserve of cardiac function could be decreased in patients with Kawasaki disease due to myocarditis even with normal echocardiography and chest X-rays.

Acute Disease↗

PubMed1994

[Clinical evaluation of aciclovir granules in the treatment of chickenpox in otherwise healthy children].

The efficacy and safety of aciclovir granules (containing 40% w/w aciclovir) were evaluated in the treatment of chickenpox in otherwise healthy children. Patients presenting with chickenpox received aciclovir granules at a dose of 20 mg/kg four times daily for five to seven days. Overall 51 children received treatment with aciclovir. A further 53 patients receiving conventional symptomatic therapy acted as a control. In the aciclovir group the overall efficacy rate was 92.2%. There were reductions in the numbers of lesions, fever, itching and the duration of symptoms. No adverse experiences were reported. Overall this formulation of aciclovir appears to be a safe and effective treatment for chickenpox in this patient population. However the need for anti-viral therapy in otherwise healthy children is still the subject of debate and it might be appropriate to identify sub-groups for whom such therapy is justified.

Acyclovir↗

PubMed1994

Bone marrow suppression induced by high dose valproic acid.

A girl with intractable epilepsy who received high dose valproic acid showed bone marrow suppression, which improved after the end of valproic acid treatment and the administration of supportive treatments. Valproic acid markedly suppressed the in vitro colony growth in this patient. It is believed that high dose valproic acid treatment directly suppressed the growth of haematopoietic progenitors, resulting in bone marrow failure.

Anemia↗