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Biomedical subjects

H Hayashi

Publications and source records attributed to H Hayashi.

At least 973 records · Page 54Linked to original sources
PubMed1993

Effects of phospholipase C on action potentials and intracellular Ca2+ concentration in guinea pig heart.

To clarify the role of phospholipase C (PLC) in arrythmias and cell injury during myocardial ischemia/reperfusion, we studied its effects on electrophysiology and [Ca2+]i in guinea pig hearts. After exposure to PLC (1 and 2 U/ml), the action potential durations of right ventricular papillary muscles were decreased. Delayed afterdepolarizations were observed in all of the preparations, and some developed into triggered activities. Developed tension decreased after an initial increase for the first 5 min, while resting tension increased consistently. The effects of PLC (0.02, 0.1, and 0.2 U/ml) on [Ca2+]i of ventricular myocytes were measured using fura-2 fluorescence. The ratio of rod-shaped cells to all cells decreased in a time- and a concentration-dependent manner. Perfusion with 0.1 U/ml PLC elevated [Ca2+]i from 56 +/- 5 nM to 245 +/- 47 nM before cell rounding, and to 1167 +/- 172 nM after cell rounding, suggesting that PLC causes Ca2+ overload. In conclusion, activation of PLC may play a role in arrhythmias and cell injury during ischemia/reperfusion. The increase in [Ca2+]i during ischemia/reperfusion may activate phospholipase, which would further increase [Ca2+]i to form a vicious cycle.

Action Potentials↗
PubMed1993

Ca2+ transients and cell shortening in diabetic rat ventricular myocytes.

To investigate the role of abnormal Ca2+ metabolism in the diminished contractile function of diabetic myocardium, we measured the Ca2+ transients and cell contraction of diabetic rat myocytes. Isolated diabetic (8 weeks after 40 mg/kg streptozotocin, i.v.) and normal myocytes were loaded with acetoxymethyl ester of indo-1 (indo-1/AM). Ca2+ transients and cell circumferential shortening were measured simultaneously, using high temporal resolution video image analysis. The diastolic base and systolic peak of Ca2+ transients were significantly lower in diabetic myocytes than in normal myocytes (peak ratios: 0.49 +/- 0.02 vs 0.56 +/- 0.01, p < 0.05; base ratios: 0.43 +/- 0.01 vs 0.48 +/- 0.01, p < 0.01, Mean +/- SE). The cell circumferential shortening of diabetic myocytes was also significantly lower than that of normal myocytes (2.9 +/- 0.3% vs 5.2 +/- 0.9%, p < 0.05). Although isoproterenol (10(-8) and 10(-7) M) increased the peak of Ca2+ transients in both diabetic and normal myocytes, the peak value of Ca2+ transients in the diabetic group was significantly lower than that in the normal group. The decreased Ca2+ transients may be responsible for the decreased contractile function in diabetic myocardium.

Animals↗
PubMed1993

24-hour ambulatory blood pressure variability in obstructive sleep apnea syndrome.

The 24-h ambulatory blood pressure (24h-ABP) was examined in 21 men, aged 38 to 65 years (mean 50.6), with obstructive sleep apnea syndrome (OSAS) and in 123 normal male control subjects, aged 40 to 60 years (mean 48.1) who did not have OSAS, obesity, autonomic nervous system abnormality, cardiac disease, or respiratory disease (group C), to assess the role of apneas in the circadian variation of blood pressure (BP). The 24h-ABP patterns in OSAS patients were classified into three types as follow: normotensive OSAS patients with normal BP throughout the 24-h period with nocturnal BP fall (type 1); hypertensive OSAS patients with progressive BP elevation from onset of sleep to early morning (type 2); and hypertensive OSAS patients with elevated BP (systolic BP > or = 140 mm Hg or diastolic BP > or = 90 mm Hg) at any time during a 24-h period (type 3). It was concluded that the circadian BP variation in type 1 was almost identical to the level and pattern of group C; the circadian variations in types 2 and 3 were significantly different from that of group C; and the patients with types 2 and 3 BP patterns had more severe OSAS than type 1 patients. The severity of OSAS was an important factor in nocturnal elevation of BP, hence affecting the circadian variation of BP. Noninvasive 24h-ABP monitoring is a useful procedure for understanding the clinical features of OSAS patients with or without hypertension.

Adult↗
PubMed1993

Effects of free radical scavengers on cytokine actions on islet cells.

We investigated the effect of free radical scavengers on the actions of cytokines on islet cells. Interferon-gamma and tumor necrosis factor-alpha reduced the nicotinamide adenine dinucleotide content of mouse islet cells; the combination of interferon-gamma (4 x 10(5) U/l) and tumor necrosis factor-alpha (4 x 10(5) U/l) caused nicotinamide adenine dinucleotide reduction by approximately 40%. Dimethyl urea and dimethyl sulfoxide prevented the decrease, whereas superoxide dismutase, catalase, and mannitol were not effective. Dimethyl urea and dimethyl sulfoxide protected islet cells from the synergistic cytotoxic action of interferon-gamma and tumor necrosis factor-alpha. Major histocompatibility complex class II antigen induction by interferon-gamma and tumor necrosis factor-alpha was also inhibited by dimethyl urea and dimethyl sulfoxide, but not by superoxide dismutase, catalase and mannitol. Since superoxide dismutase of a membrane-penetrable form attenuated the class II antigen induction, the inefficiency of superoxide dismutase, catalase and mannitol may be attributable to their inability to penetrate islet cells. These results suggest that the intracellular generation of free oxygen radicals is involved in islet cell cytotoxicity and class II molecule expression by interferon-gamma and tumor necrosis factor-alpha, and that nicotinamide adenine dinucleotide reduction may be associated with islet cell dysfunction caused by the cytokines.

Animals↗
PubMed1993

Epithelial cell kinetics with atelocollagen membranes: a study in rats.

A recent development in guided tissue regeneration procedures is the use of resorbable membranes, which eliminate the need for subsequent surgical removal. In this study we performed flap surgery in rats with (experimental) or without (control) implantation of one of the newer materials, atelocollagen. We observed the gingival epithelial cell kinetics using 3H-thymidine and examined the extent of gingival epithelium migration. Histological observations at day 1 on the experimental side demonstrated regenerated epithelium apposed to the collagen membrane with an intervening layer of necrotic tissues and/or fibrinous exudate. There was no observable proliferation of regenerated epithelium toward the root apex. On day 14, the regenerated epithelium migrated apically along the treated root surface in the control group. By contrast, on day 14 in the experimental group, the regenerated epithelium contacted the root surface at the cemento-enamel junction (CEJ). Apical to the CEJ, there was new cementum formation with inserting connective tissue fibers. Autoradiographs from day 1 experimental sides demonstrated labeled cells in the basal cell layers from oral, crevicular, and junctional epithelium. From day 1 to day 5, labeling indices of oral epithelium and regenerating crevicular epithelium on experimental sides were lower than on control sides. These histological and autoradiographic findings suggest that atelocollagen membrane inhibits apical migration of regenerating epithelium and accelerates connective tissue reattachment in part by inhibiting the mitotic function of basal epithelial cells in early stages of wound healing.

Animals↗
PubMed1993

[A case report of an ectopic ureter in a patient treated for chronic prostatitis].

A male aged 20 had been treated for anal and lower abdominal pain after ejaculation for about 2 years under the diagnosis of chronic prostatis. Because of worsening of the pain, he was admitted to our hospital in September 24, 1991. On the rectal examination, a cystic tumor was palbable on the left side of the prostate. The left kidney was not detected by IVP and ultrasonography. CT revealed two retrovesical cystic lesions in the left side. Cystourethroscopy showed an absence of ureteral orifice and ureteral ridge on the left side. Left uretero-seminal vesiculectomy was performed on October 3rd, under the diagnosis of an ectopic ureter entering into the seminal vesicle or ejaculatory duct. Histopathologically, the left ectopic ureter entering into the lower portion of the seminal vesicle or ejaculatory duct and the left renal agenesis were diagnosed. It was remarkable that ureteral epithelium was not transitional but columnar epithelium.

Adult↗
PubMed1993

[Determination of oxalic acid by high performance liquid chromatography].

In order to determine a reliable method for measuring oxalic acid, we carried out a procedure using high performance liquid chromatography. This method proved to be excellent in the case of tea and beer. In the case of urine, however, it had some problem from the aspect of reproducibility, although as far as linearity measurement, dilution test and recovery rate were concerned, accurate results could be obtained. Nevertheless, this method was thought to be unsuitable for routine clinical use, at least at present, for the reasons that it took a long time to perform the measurement, and because of the high cost of the column used in the procedure. The value of the oxalic acid as determined by this method in 24 hr urine from 12 healthy male volunteers was in the range of 17-47 mg/day (average +/- standard deviation: 25.4 +/- 9.0). To correct for their differences of physical constitution, dividing oxalic acid value by body weight rather than by urinary creatinine or body surface area was found to give a more precise value of the norm. From this calculation, it was thought that the normal range of oxalic acid value was 0.6 mg/kg or less.

Beer↗
PubMed1993

[Clinical studies of renal pelvic and ureteral tumors: an analysis of 611 registered cases and progress of treatment].

A review of 611 cases of renal pelvic or ureter tumor registered in Tokai Urological Tumor Registry for the past 10 years from 1980 and comparison of results between the first and latter half was made. The number of renal pelvis tumor was 347 and that of ureter tumors was 264. Clinical stages and pathological grades of the tumor were as follows; Ta, 11.9; T1, 31.8; T2, 14.4; T3, 24.3; T4, 17.6% and G1, 10.5; G2, 49.3; G3, 33.0%. Higher stages and grades were observed in the recent 5 years. Of 409 cases (66.9% in total cases) treated by total nephroureterectomy, 28.3% of the first and 49.0% of the latter half were treated adjunctively by chemotherapy. Five years relative survival rates of these two groups were 49.4 and 47.3%, respectively, suggesting no improved results. A new treatment strategy such as neoadjuvant chemotherapy or lymphadenectomy is expected to improve the prognosis.

Adult↗
PubMed1993

[Retroperitoneal liposarcoma with intrarenal metastases which was difficult to distinguish from angiomyolipoma. A case report].

A 40-year-old man was admitted to our hospital with a fat-density extrarenal tumor and intrarenal nodules which were detected by ultrasonography (US) and CT scan obtained the general health check. After his admission, US, CT, MRI and angiography were performed. As the final diagnostic procedure, we performed a US-guided percutaneous needle biopsy of the extrarenal tumor, because this tumor was difficult to distinguish from liposarcoma and angiomyolipoma (AML). The pathological study revealed a well-differentiated liposarcoma, and the extrarenal tumor and the left kidney were removed en bloc. Pathologically, the tumor not only invaded into the renal parenchyma directly but also have metastasized independently to the intrarenal region. Postoperatively, he received a tumor dose of irradiation of 50 Gy. Liposarcoma arising in the perirenal space should be considered in the differential diagnosis of exophytic AML. If radiological studies can not confirm the appropriate diagnosis, we consider that biopsy of the tumor should be selected as an alternative diagnostic approach. And, we think that this is the first case report dealing with intrarenal metastases of liposarcoma.

Adult↗
PubMed1993

Identification of surface-exposed parts of red-light- and far-red-light-absorbing forms of native pea phytochrome by limited proteolysis.

Peptide fragments were obtained by limited proteolysis with trypsin and Staphylococcus aureus V 8 protease from either the PR or the PFR form of 121-kDa phytochrome purified from etiolated pea (Pisum sativum L.) shoots. Patterns of bands after polyacrylamide gel electrophoresis in the presence of SDS of the digests were different, with some bands appearing preferentially when the digestions were carried out with the PR or the PFR form. Amino-terminal sequences of the fragments were analyzed to determine the exact locations of the amino-termini of the fragments within the amino acid sequence of the apoprotein of pea phytochrome. The amino acid compositions of some of the sequenced fragments were determined in order to confirm the carboxy-terminal amino acids. Three cleavage regions were identified as kinetically favored sites of cleavage of PFR (Arg-746 to Lys-752, around Glu-877 and around Arg-1010), whereas only one was identified for PR (Glu-38 to Arg-62). Regions of Glu-255, Arg-383, Arg-583 to Glu-620 and Lys-1093 to Glu-1115 were also identified as potential sites of proteolytic cleavage in both forms of the phytochrome. Other cleavage sites, the specificities of which have not yet been determined, are Glu-404, Glu-695 and Lys-1045. Surface-exposed parts of phytochrome in the PR and PFR forms are discussed.

Amino Acid Sequence↗
PubMed1993

Development of neoglycoproteins conjugated with natural oligosaccharides through carboxyl residues of proteins and its application to recombinant human interleukin 1.

In order to develop glycosylated cytokines, neoglycoproteins were synthesized utilizing naturally occurring oligosaccharides. High mannose type oligosaccharide-asparagine (Asn)s, containing Man8GN2-Asn, Man7GN2-Asn and Man6GN2-Asn, were obtained from quail ovalbumin and were coupled to bovine serum albumin (BSA) by carbodiimide-mediated coupling. Major reaction occurred between amino residues of oligosaccharide-Asns and carboxyl residues of BSA. Approximately one molecules of oligosaccharides-Asns were coupled to per molecule of BSA with 50% yield of glycosylation. Among the oligosaccharides, Man6GN2-Asn appeared to be conjugated predominantly. While this strategy was applied to recombinant human interleukin 1 alpha (IL-1 alpha), three molecules of oligosaccharide-Asns were introduced into per molecule of IL-1 with 10% yield of glycosylation.

Animals↗
PubMed1993

Cellular and subcellular alterations of the thyroid gland in rats caused by lithium carbonate.

Biochemical, hematologic, histometric, structural and ultrastructural changes were studied in the thyroid gland of rats, whom were administered Lithium carbonate. It was noted that (1) the Li carbonate had a cumulative effect on the serum; (2) T3 and T4 hormones in the blood decreased throughout the experiment; (3) the red blood cells, hemoglobin, hematocrit, platelets and leukocytes decreased gradually; (4) the diameter of the thyroid follicles, the size of the follicular cells and colloid droplets decreased, whereas the stroma was invaded by a greater number of collagen fibers and blood capillaries.

Animals↗
PubMed1993

Differential production of interleukin 1 (IL-1), IL-6, tumor necrosis factor, and IL-1 receptor antagonist by human monocytes stimulated with Mycobacterium leprae and M. bovis BCG.

Human blood monocytes cultured in various serum conditions were stimulated with Mycobacterium leprae or M. bovis BCG and their cytokine-inducing abilities were compared. BCG, either live or killed, induced production of interleukin 1 (IL-1), IL-6, tumor necrosis factor (TNF), and IL-1 receptor antagonist (IL-1ra). Live BCG at a lower bacterial number was more potent than killed BCG in the induction of IL-6 and TNF. In contrast to BCG, killed M. leprae induced few cytokines except for IL-1ra. Similar results were obtained when monocytes were cultured in the presence of untreated or heat-inactivated fetal bovine serum (FBS). When FBS and human serum (HS) were compared and the effect of heat inactivation was investigated, monocytes in HS produced the most cytokines, then those in FBS, irrespective of heat inactivation, and those in heat-inactivated HS produced the least cytokines. There were no differences between live and killed M. leprae, and BCG were far more potent than M. leprae in all of our experimental conditions, indicating that the poor cytokine (IL-1, IL-6 and TNF)-inducing ability of M. leprae was not due to their viability. Cytokine production was partially in parallel with the phagocytosis of the mycobacteria. These results suggest that M. leprae favor their infection by evoking little host reaction through the induction of only low levels of immunostimulatory or proinflammatory cytokines but a substantial amount of immunosuppressive cytokine.

Animals↗
PubMed1993

[Clinical effects of transabdominal simple hysterectomy on micturition function].

We prospectively investigated micturition function in 68 women who were operated on by transabdominal simple hysterectomy for uterine myoma. Twelve parameters including stress urinary incontinence, obstructive symptoms, irritative symptoms, uroflow curves and amount of residue were subjectively or objectively evaluated before surgery and a mean of 4.4 months post-operatively. Though 55 patients (81%) had had one or more symptoms of micturition disorders prior to operation, surgery significantly reduced this number to 32 (47%) (p < 0.01). Hysterectomy significantly decreased the number of patients suffering from stress urinary incontinence, weak urinary stream, straining micturition, interrupted stream, urgency and frequency in the daytime. The relationship between the weight of the uterus removed and pre-operative symptoms of micturition disorders was assessed. Interrupted stream was present significantly more in the patients with a uterus weighing less than 400 grams and urgency in the patients with a uterus weighing more than 401 grams. We conclude that transabdominal simple hysterectomy is of use to improve micturition disorders pre-operatively recognized.

Adult↗
PubMed1993

[Postoperative pain relief by continuous epidural infusion: a comparison of three solutions].

The effect of three solutions on postoperative pain relief by continuous epidural infusion was studied. Seventy-five patients after upper or lower abdominal surgeries were assigned to one of three groups and the postoperative pain relief was evaluated for 48 hours. Group I: bolus injection of buprenorphine (Bn) 0.1 mg + saline (S) 8 ml and continuous infusion (2 ml.h-1) of Bn 0.8 mg + S 92 ml; Group II: bolus injection of Bn 0.1 mg + 0.5% bupivacaine (Bc) 4 ml + S 4 ml and continuous infusion of Bn 0.8 mg + S 92 ml; Group III: bolus injection of Bn 0.1 mg + 0.5% Bc 4 ml + S 4 ml and continuous infusion of Bn 0.8 mg + 0.5% Bc 40 ml + S 60 ml. The combination of buprenorphine with low-dose bupivacaine (Group III) offered the most effective postoperative analgesia in three groups without increasing the frequency of adverse effects induced by epidural administration of local anesthetics. However, even in Group III, the percentage of patients complaining of pain at bed rest was still high during early postoperative period (56% at 6 hours postoperatively). The results suggest that further consideration is necessary on agents selection and dosage adjustment for the postoperative epidural analgesia.

Aged↗
PubMed1993

Hepatic copper accumulation in patients with primary biliary cirrhosis.

Liver biopsy specimens from 18 patients with primary biliary cirrhosis were examined histochemically and by energy-dispersive x-ray microanalysis. Using two indices, we classified hepatic copper accumulation into three stages based on the Cu x-ray intensity of cuproproteins that had accumulated in hepatocyte lysosomes and on the binding ratio of postulated copper transfer proteins between the cytosol and lysosomes. Eight patients were in stage 1 with an initial accumulation of lysosomal cuproproteins, mediated by transfer proteins not saturated with copper. Two patients were in stage 2, in which transfer proteins were saturated with copper. The first two stages gave negative results for histochemical copper. The remaining eight patients were in stage 3, in which copper accumulation detected by histochemical included transfer proteins saturated with copper and large amounts of lysosomal cuproproteins. Five patients (one each in stages 1 and 2, and three in stage 3) underwent a second liver biopsy after treatment with 600 mg of ursodeoxycholic acid daily for 14 to 39 months. Results of blood chemistry tests improved, but liver histologic findings and copper accumulation were unchanged in all five patients. It seems likely that ursodeoxycholic acid does not affect the copper accumulation in hepatocyte lysosomes that reflects the state of cholestasis in patients with primary biliary cirrhosis.

Adult↗
PubMed1993

Intrahepatocellular localization of copper in Wilson's disease.

It is well known that excess copper plays a role in the pathogenesis of Wilson's disease; however, the hepatic copper contents, determined either histochemically or biochemically, are not always correlated with the activity of Wilson's disease. To better understand copper-induced cytotoxicity, intrahepatocellular localization of copper was studied in five patients with Wilson's disease. The liver specimens were obtained by biopsy to confirm the clinical diagnosis of Wilson's disease before treatment. Neither hepatic copper content nor histochemical copper deposits were correlated with any of the biochemical indices studied. Energy-dispersion X-ray microanalysis was done on the nuclei, lysosomes and lysosome-free cytoplasm of hepatocytes. Lysosomes had the highest Cu X-ray intensity but no correlation was shown between the lysosomal copper content and biochemical indices. The nucleus/lysosome-free cytoplasm ratio of the copper content was correlated with the serum levels of aminotransferases. These results suggest that the copper increasing gradient from the lysosome-free cytoplasm to the nucleus is associated with hepatocyte necrosis, and probably causes irreversible nuclear damage.

Adolescent↗