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Biomedical subjects

Y Miyauchi

Publications and source records attributed to Y Miyauchi.

At least 73 records · Page 4Linked to original sources
PubMed1995

Feasibility of in vitro culturing of lesional psoriatic keratinocytes in medium containing high calcium concentrations.

Lesional psoriatic keratinocyte (LPK) culture is considered to be difficult under high-Ca2+ conditions in the absence of special proliferative agents. Using a permeable collagen membrane, we obtained a culture of LPKs under high-Ca2+ conditions without any special proliferative agents. Single-cell suspensions were prepared from the epidermis of chronic psoriatic plaques. Cells were inoculated on the collagen membrane suspended slightly above the bottom of a Petri dish. We used a culture medium of Eagle's MEM containing 10% fetal calf serum. LPKs attached to the membrane 12 h after inoculation and gradually spread. They reached a confluent state by the 10th day of culture. We measured the concentrations of TGF alpha and IL-6 in the medium of LPKs, and compared these with the concentrations in normal keratinocyte (NK) cultures. Significantly increased secretion of TGF alpha by LPKs was observed during the initial phase but this secretion subsequently decreased. Concentrations of IL-6 were below the detectable level in both of NKs and LPKs throughout the observation period. Our results demonstrate that cultured LPKs under high-Ca2+ conditions secrete a larger amount of TGF alpha but not IL-6. Our cell culture system, which allows LPKs to spread and stratify, contributes to the study of the pathogenesis of psoriasis.

Adult↗
PubMed1995

Changes in circulatory status and transport function of the liver induced by reactive oxygen species.

To elucidate the pathogenesis of microcirculatory disturbance of the liver after ischemia and reperfusion, the effect of reactive oxygen species on hepatic circulatory status and transport function for a cholephilic compound was studied in an isolated perfused rat liver. Perfusion of the liver with a medium containing hypoxanthine and xanthine oxidase significantly increased the portal pressure, with concomitant decrease in intrahepatic vascular volume and hepatic uptake of bromosulfophthalein (BSP). Similar changes were also elicited by infusion of serotonin, which induces contraction of sinusoidal endothelial cells. Either superoxide dismutase or catalase added in the perfusion medium partially inhibited the oxidase-induced changes in portal pressure, vascular volume of hepatic sinusoid, and BSP transport. In the presence of superoxide dismutase, either catalase or erythrocytes inhibited the oxidase-induced changes completely. These results indicated that superoxide anion and hydrogen peroxide might induce contraction of hepatic resistance vessels, capacitance vessels, and/or sinusoidal endothelial cells and that this contraction decreased the vascular bed in the liver and the time for interaction of circulation substrates with hepatocytes, thereby decreasing hepatic transport for cholephilic ligands such as BSP.

Animals↗
PubMed1995

Endotoxemia and intestinal mucosal dysfunction after the relief of obstructive jaundice by internal and external drainage in rats.

We studied the effects of external and internal biliary drainage on the development of endotoxemia in a rat model of obstructive jaundice. Male Donryu rats were allocated to four groups: sham operation, common hepatic bile duct ligation (BDL), internal or external biliary drainage after BDL, and biliary drainage after BDL with oral endotoxin administration. Portal and systemic blood endotoxin concentrations were measured and the histomorphology of the intestinal mucosa was examined. Portal endotoxemia was observed 7 days after BDL and both portal and systemic endotoxemia were observed after 14 days. Portal endotoxemia was reversed by both internal and external biliary drainage and systemic endotoxemia was prevented. The ratio of villous height to crypt depth in the mucosa of the terminal ileum was decreased in rats with external drainage. Oral administration of endotoxin induced marked disruption of the mucosal epithelium in rats with external biliary drainage, but not in rats with internal biliary drainage. Significant increases in portal and systemic blood endotoxin concentrations were observed only in the external drainage group after oral endotoxin administration. The relief of biliary obstruction effectively relieved portal endotoxemia. External biliary drainage, however, has the potentially deleterious effect of disrupting the intestinal mucosa, which may promote the development of endotoxemia. These findings have implications for the use of biliary drainage procedures to reduce postoperative complications in jaundiced patients.

Animals↗
PubMed1995

Streptococcal toxic shock syndrome: report of two cases.

Two Japanese cases of streptococcal toxic shock syndrome (STSS) are reported. The first patient was a 45-year-old male who developed necrotizing fasciitis and myositis of the left thigh, refractory hypotension, hepatic dysfunction and acute renal failure; the patient died despite treatment. Streptococcus pyogenes was isolated from the inflamed fascia. The second patient was a 69-year-old female who had coagulopathy, polymyositis and hepatic function abnormality. Streptococcus pyogenes was isolated from blood culture. She was immediately placed on high-dose ampicillin as well as other supportive measures, and she survived.

Aged↗
PubMed1995

Immunohistochemical and ultrastructural detection of advanced glycation end products in atherosclerotic lesions of human aorta with a novel specific monoclonal antibody.

To elucidate the deposition of advanced glycation end products (AGEs) in aortic atherosclerosis, aortic walls were obtained from 25 autopsy cases and examined immunohistochemically and immunoelectron microscopically with a monoclonal antibody specific for AGEs, 6D12. Among the autopsy cases, atherosclerotic lesions were found in the aortas of 22 cases and were composed of diffuse intimal thickening, fatty streaks, atherosclerotic plaques, and/or complicated lesions. In these cases, intracellular AGE accumulation was demonstrated in the intimal lesions of aortic atherosclerosis in 12 cases. Compared with the diffuse intimal thickening, intracellular AGE accumulation was marked in the fatty streaks and atherosclerotic plaques. Immunohistochemical double staining with 6D12 and monoclonal antibodies for macrophages or muscle actin or a polyclonal antibody for scavenger receptors demonstrated that the AGE accumulation in macrophages or their related foam cells was marked in the diffuse intimal thickening and fatty streak lesions and that almost all macrophages and macrophage-derived foam cells possessed scavenger receptors. Immunoelectron microscopic observation revealed the localization of 6D12-positive reaction in lysosomal lipid vacuoles or electron-dense granules of the foam cells. These results indicate that AGE accumulation occurs in macrophages, smooth muscle cells, and their related foam cells.

Adult↗
PubMed1995

Efficacy of slow-releasing anticancer drug delivery systems on transplantable osteosarcomas in rats.

New drug delivery systems for cis-diamminedichloroplatinum (CDDP) incorporated into vehicles, such as polymethylmethacrylate (PMMA), fibrin glue (F.G.), alpha-tricalciumphosphate (TCP) and ethylenevinyleacetate copolymer (Polymer) were examined using a rat osteosarcoma model. The materials containing CDDP were directly implanted into the tumors or subcutaneous tissue of rats, and the inhibitory effects on tumor growth and lung metastasis were evaluated. Data on in vitro kinetics of CDDP release revealed good results for both TCP and F.G., and the release pattern from TCP to be most appropriate for a slow-releasing drug delivery system. This was supported by the results of the implantation experiments, whereby the direct implantation of TCP containing CDDP (CDDP-TCP) into tumors, gave significantly better inhibitions of tumor growth and metastasis than either non-treatment (P < 0.01) or subcutaneous implantation (P < 0.05). In a second experiment, using different administration procedures, different inhibitory effects on tumor growth and lung metastatic potency were observed with intra-arterial and intravenous CDDP administration, as well as with CDDP-TCP implanted subcutaneously. Suppression effects of CDDP (10 mg/kg)-TCP directly implanted into tumors were equal to those of intra-arterial (2.5 mg/kg) and intravenous (5.0 mg/kg) administrations. The present results suggest CDDP-TCP implantation to be effective as a slow-release drug delivery system for inhibiting tumor growth and metastasis, and that it should be a useful adjuvant to conventional i.v. or i.a. chemotherapy.

Animals↗
PubMed1995

Effects of serine protease and deoxyribonuclease on intravascular tumor cell arrest in rat blood-borne lung metastasis.

Effects of alpha-chymotrypsin and deoxyribonuclease I (DNase I) on the early phase of blood-borne lung metastasis in rats were studied using confocal laser scanning microscopy and AH-109A cells labeled either with carboxyfluorescein diacetate succinimyl ester or with 51Cr. Intravenous administration of alpha-chymotrypsin or DNase I appeared to enhance or inhibit, respectively, the tumor cell arrest in lung microvasculature as a reflection of reduction or promotion of the tumor cell clearance in the microvasculature. These results suggest that the effects of alpha-chymotrypsin and DNase I are related to induction of tumor cell aggregation and disaggregation in the blood stream, respectively.

Animals↗
PubMed1995

[Oxygen economy in patients after open heart surgery--effects of cardiopulmonary bypass on oxygen metabolism].

The relationship between oxygen delivery (DO2) and oxygen consumption (VO2) was studied in thirty patients who underwent open heart surgery. Delivery dependent consumption was observed for the first 48 hours after the surgery even DO2 was in a physiological range (> 300 ml/min/m2). VO2 decreased in proportion to a decrease in DO2 (VO2 = 0.132 x DO2 + 87.9, R = 0.616, p < 0.001). Oxygen extraction rate (ER = VO2/DO2) increased also in proportion to a decrease in DO2 (ER = -0.385 x DO2 + 51.8, R = -0.722, p < 0.001). These results suggest that tissue oxygen demand in the early postoperative period is higher than physiological conditions. Factors which directly influenced ER were cardiac index (CI) and hemoglobin (Hb) as expressed in the following formulas; ER = -6.05 x CI + 51.6 (R = -0.592, p < 0.001), ER = -2.02 x Hb + 56.7 (R = -0.414, p < 0.001). This indicates that hypoperfusion and anemia deteriorate oxygen metabolism in the early postoperative period. As a monitor of oxygen demand, oxygen saturation of mixed venous blood (SvO2) was an useful parameter to indicate the ER (ER = -0.872 x SvO2 + 91.9, R = -0.969, p < 0.001).

Adult↗
PubMed1995

Efficacy of the angiogenesis inhibitor O-(chloroacetyl-carbamoyl)fumagillol (AGM-1470) on osteosarcoma growth and lung metastasis in rats.

The efficacy of the anti-angiogenic agent, O-(chloroacetyl-carbamoyl)fumagillol (AGM-1470), against primary tumor growth and spontaneous lung metastasis was evaluated experimentally using a transplantable osteosarcoma line in rats previously established in our laboratory. Male Fischer 344 rats bearing the tumor with a high potential for metastasis received intermittent or continuous subcutaneous administrations of AGM-1470. Both treatment regimens resulted in significant inhibitions of spontaneous lung metastasis and primary tumor growth in a dose-dependent manner, with continuous administration of AGM-1470 exerting the most pronounced inhibitory effects on both parameters.

Animals↗
PubMed1995

[Effects of carbon monoxide produced during laparoscopic surgery].

One of the complications of laparoscopic surgery is carbon monoxide (CO) production under the use of electro-cautery. We studied 11 patients undergoing laparoscopic urological surgery. The concentrations of CO in peritoneal cavity and carboxyhemoglobin (HbCO) in arterial blood were measured before the operation under laparoscopy, during the use of electro-cautery and after the operation. The concentration of CO in peritoneal cavity reached 78 ppm during the use of electro-cautery but the HbCO level was unchanged. In the study on laparoscopic cholecystectomy (LC) performed previously, we had found no change of HbCO. The increase of CO on LC was more pronounced than in the present study. The concentration of CO in peritoneal cavity might be more dependent on the intensive use of electro-cautery than on operation time. Additionally the frequency of the insertion and extraction of the instruments through the trocar could have influenced it. CO could also be produced in the carbon dioxide cylinder. It should be investigated since it might contaminate the operating room.

Adult↗
PubMed1994

The effect of perioperative portal venous injection of donor spleen cells on renal allograft survival in dogs.

Preoperative portal venous injection of donor lymphocytes has been shown to extend allograft survival in inbred animals. However, the effect of perioperative injection in a large animal model has not been carefully studied. We examined the effect of perioperative (day 0) donor spleen cell administration in a canine kidney transplant model using both a double-donor transplantation and a single-donor survival study. In the double-donor model, two kidneys from two separate donors were transplanted into a single recipient. Spleen cells obtained from only one of the donors were injected through the portal vein immediately after reperfusion of the allografts. Both allografted kidneys were resected 14 days after transplantation and studied. There was only a slight cellular infiltrate in the kidney derived from the donor from whom spleen cells had been obtained, whereas a much more extensive cellular infiltrate as well as edema and hemorrhage were present in the other kidney. In a survival study of single allografts, the injection of 2 x 10(9) spleen cells significantly prolonged the mean survival time (15.0 +/- 3.4 days) compared with untreated recipients (6.6 +/- 2.2 days). Addition of cyclosporine did not significantly prolong survival in the spleen cell inoculated animals. These findings suggest that perioperative protal venous injection of donor cells may be a specific immunosuppressive method useful in clinical organ transplantation.

Animals↗
PubMed1994

Ca(2+)-inhibition of Ca(2+)-induced small contraction of rat uterine smooth muscle.

Ca2+ has been reported to exert an inhibitory effect on various kinds of smooth muscle. The physiological role of this inhibition is unclear. We investigated the inhibitory action of Ca2+ on the uterine smooth muscle of the rat in estrus, which shows a prominent Ca(2+)-induced inhibition. At concentrations of 0.1-30 microM Ca2+ inhibited the Ca(2+)-independent contraction of this muscle induced by oxytocin in Ca(2+)-free medium. We then investigated the inhibitory action of Ca2+ at various concentrations of Ca2+ in the bathing medium and found that Ca2+ at 1.0-10 microM also inhibited Ca(2+)-dependent contractions, which appeared phasically upon the onset of contractions. The magnitude of these phasic contractions was inversely proportional to the concentration of Ca2+ (between 1-10 microM). At 30 microM Ca2+, however, this inhibition was overcome and large pendular contractions began. Thus, the inhibition may regulate the initiation of smooth muscle contractions. The mechanism of this Ca(2+)-induced inhibition is also discussed with regard to an effect on actin.

Actins↗
PubMed1994

Increase in 3-deoxyglucosone levels in diabetic rat plasma. Specific in vivo determination of intermediate in advanced Maillard reaction.

A specific assay of 3-deoxyglucosone (3-DG) was developed in our laboratory to help elucidate the relationship between advanced Maillard reaction and diabetic complications. 3-DG is known as a highly reactive intermediate of the reaction in vitro and a precursor of advanced glycosylation end products such as pyrraline and pentosidine, which have been previously detected in vivo. 3-DG was converted to a stable compound, 2-(2,3,4-trihydroxybutyl)-benzo[g]quinoxaline, by reacting with 2,3-diaminonaphthalene. Since the derivative had a characteristic UV spectrum, it was determined at 268 nm by high performance liquid chromatography. This method was sensitive enough to detect 10 ng/ml (61.7 nM) of 3-DG in vitro. A slight modification to this method allowed in vivo detection of small amounts of 3-DG. Plasma free 3-DG levels were significantly higher in streptozotocin-induced diabetic rats compared with controls (918 +/- 134 nM versus 379 +/- 69 nM, p < 0.001) and were suppressed with the administration of aminoguanidine, an inhibitor of Maillard reaction. Plasma pyrraline levels in diabetic rats also increased in parallel with elevated 3-DG levels but were only marginally suppressed by administration of aminoguanidine. Our results indicate that 3-DG is present in vivo under normal conditions and that its level increases in diabetic subjects. Determination of 3-DG represents a good tool to predict development and progression of diabetic complications and to assess the efficiency of inhibitors to Maillard reaction.

2-Naphthylamine↗
PubMed1994

Electron microscopic evidence of a viral nature for osteoclast inclusions in Paget's disease of bone.

Circumstantial evidence from electron microscopic and immunological studies support the view that Paget's disease of bone represents a slow virus infection. However, there is only limited information available regarding its electron microscopic, enzyme and immunocytochemical characteristics. Two cases were studied using electron microscopy with particular emphasis on the inclusions in osteoclasts. Detailed ultrastructural and cytochemical studies including immuno-electron microscopy were performed. Some osteoclasts demonstrated specific virus-like structures composed of aggregations of microtubules in the nucleus and cytoplasm. The structures were easily digested by trypsin or protease, and were sensitive to RNase, which provided substantial evidence of a proteinaceous nature and inclusion of ribonucleic acid. Immunocytochemical examination identified binding of anti-respiratory syncytial virus and anti-measles virus antibodies in the tissue obtained from one of the two cases examined. The presence of viral antigens in structures in the cytoplasm of Pagetic osteoclasts supports the theory of paramyxovirus involvement in this disease.

Antigens, Viral↗