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Biomedical subjects

M Ochi

Publications and source records attributed to M Ochi.

At least 199 records · Page 11Linked to original sources
PubMed1991

Experimental irradiation of femoral arteries by carbon dioxide (CO2) laser: morphologic changes under transmission electron microscope (T.E.M.) examination.

In order to study the morphologic changes after CO2 laser irradiation, 42 rat femoral arteries were irradiated under various conditions at different time intervals from zero to three weeks. The arteries were examined under transmission electron microscope (T.E.M.), and 30 mW power and 0.3 to 0.5 mm/sec velocity were considered to be the most suitable for a CO2 anastomosis of small femoral arteries.

Animals↗
PubMed1991

New adipocyte formation in mice during refeeding after long-term deprivation.

Cell kinetic characteristics of the epididymal adipose tissue of mice were examined during refeeding after prolonged food deprivation. Mature mice were given a glucose-electrolyte solution for 20-40 days, and subsequent to a body weight loss of 35%, they were given normal mouse food ad libitum. After refeeding, their body weight and adipose tissue weight returned to the levels before the deprivation. We examined the formation of new adipocytes in the epididymal adipose tissue with [3H]thymidine autoradiography. Flash labeling experiments revealed that cell proliferation was most active on the 6th day after refeeding and decreased thereafter until the 13th day when few labeled cells were seen. Cumulative labeling experiments showed that replicated poorly differentiated mesenchymal cells developed into adipocytes by storing fat droplets. New adipocyte formation was observed in adult mice during refeeding after long-term deprivation.

Adipose Tissue↗
PubMed1991

Adipocyte dynamics in hypothalamic obese mice during food deprivation and refeeding.

Effect of hypothalamic lesions on regulation of body weight and fat cell dynamics in obese mice were examined during refeeding after prolonged food deprivation. Obese mice, which were treated with monosodium glutamate for 5 postnatal days and had ventromedial nuclear lesions in the hypothalamus, were used. When adult obese mice were given a glucose electrolyte solution for 20-40 days, the body weight dropped to about 45% of their pre-treatment weight. After reinstituted feeding of normal mouse food ad libitum, their body weight and adipose tissue weight returned to pre-starvation level. Tritiated thymidine autoradiography revealed that cell proliferation occurred in the early stages of refeeding and some fat cells were renewed in the epididymal adipose tissue. Fat cell renewal was found more active in the experimental group than in the control. Thereafter, fat cell size increased gradually via fat storage. These obese mice were found to have the capacity to regulate their body weight and adipose tissue not only through fat storage but also by increasing number of fat cells, in order to replace the cells which were lost during starvation. Therefore, ventromedial nuclear lesion in the hypothalamus does not influence the regulatory mechanism of adipose tissue during starvation and refeeding.

Adipose Tissue↗
PubMed1991

[Arterial graft anastomosis in coronary artery surgery: some technical points].

To facilitate surgical technique, we describe some devices on arterial graft anastomosis in coronary artery surgery. Prior to anastomosis, the graft is positioned closely just parallel to the coronary artery by fixing surrounding endothoracic fascia or other connective tissues to the epicardium with 5-0 monofilament sutures. Stitching around the heel of the anastomosis is best performed by "a single stroke continuous suture" with the graft kept in position parallel to the coronary artery. This technique provides simple and secure anastomosis of an arterial graft.

Anastomosis, Surgical↗
PubMed1991

[Surgical management of peripheral vascular disease in patients with severe coronary artery disease: importance of operative concept to reconstruct catheter insertion route for PTCA or CABG].

We discussed the operative concept of revascularization of lower extremities in patients associated with severe, coronary artery disease (CAD). Those with symptomatic CAD may undergo coronary artery bypass (CABG) or percutaneous coronary angioplasty (PTCA) with or without intraaortic balloon pump (IABP). Special attention should be paid during operation in these patients in order to reconstruct the arterial catheter route, which gives us the best way to percutaneous transfemoral approach to the aorta or the coronary arteries. One should not choose arbitrarily extra-anatomical bypass, such as axillo-femoral or femorofemoral, in these cases. Also, artificial graft should not be applied in the common femoral arteries, which will make percutaneous approach difficult. Common femoral arteries, if needed, are best reconstructed by means of thromboendarterectomy. Attaining smooth, bilateral aorto-ilio-femoral continuity is the main goal of revascularization of lower extremities in patients with CAD.

Aged↗
PubMed1990

Peripheral nerve allograft: cellular and humoral immune responses of mice.

Despite numerous experimental and clinical studies, no method has been established for achieving successful peripheral nerve allografts. One reason is that few studies concerning the immune response of the host have been conducted with nerve allografts. We therefore investigated the immune response of fresh nerve allografts with respect to both cellular and humoral immunological reactions. Using immunologically established strains of inbred mice, we performed the mixed lymphocyte culture (MLC) reaction and the cell-mediated lymphocytolysis reaction to test the cellular immune reaction and the complement-dependent cytotoxicity test to the humoral immune reaction. We observed that peripheral nerve tissues were strongly immunogenic; there was increased MLC reactivity to the allo-MHC antigen of the donor, specific cytotoxic T-cell activity, and production of specific antibody in the serum. For satisfactory nerve regeneration and transplantation, it is essential to suppress this immune response.

Animals↗
PubMed1990

The effects of salicylate on ketogenesis, gluconeogenesis and urea production in rat liver perfusion.

In order to elucidate the relation between the hepatotoxicity of salicylate (SA) and the pathogenesis of Reye's syndrome (RS), urea production, gluconeogenesis and ketogenesis were investigated in isolated perfused rat livers in the presence of salicylate (SA) and oleate. Although urea formation from 0.5 mM NH4Cl, 2 mM ornithine and 0.3 mM oleate was not inhibited by infusion of SA, 3 mM SA caused a 26% decrease of ketogenesis, 85% decrease of 3-hydroxybutyrate/acetoacetate ratio (30HB/AcAc) and 45% increase of oxygen consumption. Glucose production from 2 mM pyruvate in the presence of 0.3 mM oleate decreased by 33% after administration of 3 mM SA, and 30HB/AcAc ratio also decreased by 33%. The decrement of gluconeogenesis and that of the 30HB/AcAc ratio were very close. These results suggested that ATP production was maintained but that the intra-mitochondrial redox state was changed to a more oxidized state after SA administration in perfused rat livers. This change in redox state could be responsible for the decrease of gluconeogenesis. Metabolic characteristics found in RS were not obtained by infusion of 3 mM SA and 0.3 mM oleate in rat livers. Therefore, some other factors in addition to SA seem necessary to establish an animal model of RS.

Animals↗
PubMed1989

Effect of the binding of bilirubin to either the first class or the second class of binding sites of the human serum albumin molecule on its photochemical reaction.

The kinetics of the photochemical changes of bilirubin were studied at a constant concentration of bilirubin bound either to the first class or to the second class of binding sites of the human serum albumin molecule. The more the bilirubin binds to the first class of binding sites in the human serum albumin molecule, the more readily geometric photoequilibrium to give (ZE)-bilirubin takes place. The more the bilirubin binds to the second class of binding sites or allosterically transformed binding sites induced by added SDS, the more readily structural photoisomerization, i.e. the formation of (EZ)-cyclobilirubin, takes place. When the serum bilirubin concentration is at low, safe, values bilirubin binds exclusively to the first class of binding sites and serves as an antioxidant [Onishi, Yamakawa & Ogawa (1971) Perinatology 1, 373-379]; at these concentrations human serum albumin protects bilirubin from irreversible photodegradation by only allowing readily reversible geometric photoisomerization. As the serum bilirubin concentration increases to high, and potentially dangerous, values, bilirubin binds to the second class of binding sites, and under these conditions human serum albumin seems to promote the photocyclization of bilirubin. During irradiation human serum albumin seems to act by retaining low, useful, concentrations of bilirubin while facilitating irreversible photoisomerization of excess bilirubin.

Bilirubin↗
PubMed1989

Administration of human leukocyte interferon to patients with subacute sclerosing panencephalitis.

Between 1979 and 1982, fifteen patients with SSPE were treated with human leukocyte interferon (HuIFN-alpha). They were administered interferon (IFN) in doses ranging from 25 x 10(6) IU to 126 x 10(6) IU by various routes in regimens that ranged for 20 days to 14 months. In 3 of the 5 cases with rapid deterioration, HuIFN-alpha did not alter the course of the disease; however, 6 cases with mild progression showed various degrees of clinical improvement during the IFN therapy. In 3 of the 4 cases in remission, HuIFN-alpha caused no significant changes in clinical courses. No severe adverse reactions were seen during IFN administration. These results suggest that HuIFN-alpha has a potentially beneficial effect on the course of SSPE.

Adolescent↗
PubMed1989

Suppression by cyclosporine of cellular and humoral reactivity after peripheral nerve allografts in mice.

Peripheral nerve allografting has been the subject of many experimental and clinical studies. As yet, however, no successful method has been established. One reason is the lack of detailed studies on the immune response under different conditions. We examined both the cellular and humoral immune responses in fresh sciatic nerve allografts in inbred mice, using a mixed lymphocyte culture reaction and a lymphocyte-mediated cytotoxicity to examine cellular immunity and a complement-dependent cytotoxicity test to examine humoral immunity. Enhanced MLC activity against donor allogenic major histocompatibility complex antigens was demonstrated, and specific cytotoxic T cell activity and the production of specific antigens in serum also were observed. Thus peripheral nerve tissue exhibited potent immunogenicity. We used cyclosporine, an immunosuppressive agent, to suppress the immune response and obtain favorable nerve regeneration. We performed immunologic and histologic studies to establish a causal relationship. Administration of 20 mg of CsA suppressed both the cellular and humoral immune response to levels comparable to those seen in isografting. Histologic examination disclosed favorable regeneration of axons, also comparable to that seen in isografts.

Animals↗
PubMed1989

[A study on adhesive strength of cyanoacrylate dental adhesive, 'F.H. Cement'--thermal-cycled effects].

This study investigated the adhesive strength of cyanoacrylate dental adhesive, 'F.H cement' after being thermal-cycled in order to certify its stability in water. The adhesive strength was compared using Zinc phosphate cement, Glass ionomer cement, Dental adhesive resin and F.H cement when an ivory die and a cast crown were adhered by these different cements. Results of the study indicated the following: 1. The adhesive strength after being thermal-cycled indicated that F.H cement had a greater strength than the other cements (Zinc phosphate cement and Glass ionomer cement) and was equal to that of the Dental adhesive resin. 2. F.H cement was also found to be the strongest in adhesive strength when different tapers were used.

Cyanoacrylates↗
PubMed1989

[Study on castable glass ceramics (Bioram-C)--surface treatment for enhanced bonding strength].

This study evaluated the tensile bonding strength of castable glass ceramics (Bioram-C) to three dental adhesive resin cements: Super-Bond C&B, Chemiace and Panavia EX. Treatments of the castable glass ceramic surfaces for enhanced bonding to the adhesive were examined. The surface treatments of the ceramics were sand blasting by 40 microns phi aluminum oxide and a silane coupling agent (KBM 503). Castable glass ceramics were cast and after surface treatment, bonded end-to-end and tested for tensile strength 24 hours later. Failures in the bonding were studied by a scanning electron microscope and wave dispersive X-ray Micro-analyzer. The findings were as follows: 1. Sand blasting by 40 microns phi aluminum oxide with Super-Bond C&B gave the highest mean bonding strength. 2. A significant difference (p less than 0.01) was observed between the surface treatment with the silane coupling agent and 40 microns phi aluminum oxide. The silane coupling agent employed in this study had a significant by higher average bonding strength. In examining the specimens, cohesive failure was observed in 70% of Super-Bond C&B and 50% of both Chemiace and Panavia EX bondings. 3. There were no significant difference between the three adhesives with the silane coupling agent.

Adhesives↗
PubMed1989

[The assessment of the safety of vacuum extraction deliveries under routine epidural block].

To assess the safety of vacuum extraction (V.E.) deliveries under continuous lumbar epidural block (E.B.) with Bupivacain, the modified Krebs score in CTG, Apgar score, cord arterial blood acid-base balance, hypoxanthine, CPK, CPK-BB, Neuron specific enolase and c-AMP were examined. A total of 74 full term oxytocin-induced labors were divided into three groups: A) 21 cases by V.E. under E.B., B) 34 cases under E.B. only, and C) 19 cases without V.E. or E.B. There was no difference in age, gestational weeks in the three groups. However, the incidence of primiparas was highest in group A. Though CTG showed a temporary low Krebs score in group A within 30 minutes after the initiation of E.B., it was found that there was no significant difference between the three groups 30 minutes before parturition. The apgar score, cord arterial blood pH, PO2 and B.E. were also found to be similar in all three groups. Among various kinds of substances in the cord blood, both CPK-BB and c-AMP showed a striking rise in group A, compared to groups B and C. Therefore, the use of V.E. under E.B. might be hazardous to the well-being of the newborn infant.

Accident Prevention↗
PubMed1988

Axonal growth in mesothelial chambers: effects of a proximal preconditioning lesion and/or predegeneration of the distal nerve stump.

Preformed, autologous mesothelial chambers were utilized to study axonal growth following selective predegeneration of the distal nerve stump and/or preconditioning of the proximal nerve stump. The left and/or right sciatic nerve of rats was exposed and transected in the thigh. Two weeks after transection, the left proximal nerve stump was cross-anastomosed with the right distal nerve stump by using a mesothelial chamber leaving a 15-mm gap between the two nerve stumps. Previous studies have shown that axonal overgrowth normally does not occur over this gap distance to the distal stump. Three months after cross-anastomosing, regeneration across the 15-mm gap was evaluated by muscle action potential recordings and light microscopical examination. In experiments in which a distal nerve stump was selectively degenerated and the proximal segment was freshly cut, axons had bridged the 15-mm gap in six of seven rats. When a proximal preconditioned nerve stump was matched with a freshly cut distal stump, axonal overgrowth occurred in only 4 of 10 experiments. In experiments including a proximal preconditioned nerve stump and a distal predegenerated stump, axons bridged the gap in 6 of 8 experiments. We concluded that a priming lesion, including manipulation with proximal and/or distal stump, enhances axonal growth in mesothelial chambers.

Animals↗
PubMed1988

Morphology and cell dynamics of adipose tissue in hypothalamic obese mice.

Morphological and cell kinetic characteristics of the epididymal adipose tissue of obese mice, induced by monosodium glutamate (MSG), were examined in comparison to those of normal mice. Mice treated with MSG for 5 postnatal days became obese after 8 wk of age; adipocytes of the MSG-treated mice were larger than those of normal mice. Heterogeneity was noted in components of the adipose tissue in the obese mice after 24 wk; various-sized adipocytes appeared, and the connective tissue elements increased; necrosis of adipocytes was observed by 36 wk; and mononuclear cells and macrophages infiltrated around the necrotic adipocytes. Such changes were not seen in normal mice. Autoradiographic study with continuous and pulse labeling with [3H]thymidine showed that half the fat cells were replaced in 150-200 days in normal mice and that the turnover rate of adipocytes was more rapid in the obese mice than in the normal mice. In the obese mice, cell death and cell renewal were found to occur more actively.

Adipose Tissue↗