Biomedical subjects

T Satoh

Publications and source records attributed to T Satoh.

1,411 records · Page 79Linked to original sources

PubMedDate not supplied

Protective effect of pacing on reperfusion-induced ventricular arrhythmias in isolated rat hearts.

OBJECTIVES: To determine whether pacing would have a protective effect similar to preconditioning on reperfusion-induced ventricular arrhythmias and whether this protective effect would be induced by pacing-induced myocardial ischemia. DESIGN: Isolated rat hearts (n = 36) were perfused by the Langendorff technique and the working heart mode. Global ischemia was induced for 10 mins followed by reperfusion for 15 mins. The control group had no pacing, while in the other groups, the hearts were electrically paced three times at 300, 400 and 600 beats/min, respectively, for 5 mins with 1 min intervals between pacings. MAIN RESULTS: The incidence of reperfusion-induced ventricular fibrillation in controls was 100%, whereas that in the 300, 400 and 600 beats/min groups was reduced to 67% (not significant), 50% (P < 0.03) and 30% (P < 0.01), respectively. The mean duration of reperfusion-induced ventricular fibrillation was also significantly reduced in the 300, 400 and 600 beats/min groups compared with the control group. Coronary flow during pacing in the 400 and 600 beats/min groups, but not the 300 beats/min group, was reduced significantly compared with controls. In the 300 beats/min group, oxygen tension of the coronary effluent during pacing was decreased significantly, and proton production and lactate release of coronary effluent during pacing were increased significantly compared with the control group. CONCLUSIONS: Pacing exerted a protective effect similar to preconditioning against reperfusion-induced ventricular arrhythmias. Pacing-induced mild myocardial ischemia, in which coronary flow was maintained, may be involved in the mechanism of this protective effect.

Animals↗

PubMedDate not supplied

Species differences in the induction of hepatic microsomal carboxylesterases caused by dietary exposure to di(2-ethylhexyl)phthalate, a peroxisome proliferator.

The ability of di(2-ethylhexyl)phthalate (DEHP), a very widely used commercial plasticizer, to induce hepatic microsomal carboxylesterase isozymes in rats, mice (C5BL/6 and DBA/2 strains), and hamsters was studied by measuring hydrolase activities and by immunoblotting analysis using specific antibodies. Animals were given 2% (v/w) DEHP in the diet for 7 days. In rats, p-nitrophenyl acetate, isocarboxazid, and butanilicaine hydrolase activities and the contents of RL1, RL2, and RH1 in liver microsomes were all increased, but acetanilide hydrolase activity was not increased. In hamsters, the only significant change was a slight increase of butanilicaine hydrolase activity. In mice, butanilicaine hydrolase was strongly induced in both the C57BL/6 (7.35-fold) and DBA/2 (4.96-fold) strains. The anti-RL1 and RH1 antibody-reactive proteins in C57BL/6 mouse liver microsomes were increased, but the extent of induction was much less than that of butanilicaine hydrolase activity. The butanilicaine hydrolysis seems to be catalyzed by not only anti-RL1 reactive protein, but also some other carboxylesterase in C57BL/6 mouse. Anti-RL1 antibody inhibited the DEHP-induced butanilicaine hydrolase activity by > 50%. The results strongly suggest that multiple carboxylesterase isozymes were induced in mouse hepatic microsomes by dietary exposure to DEHP.

Animals↗

PubMedDate not supplied

Pheochromocytoma with multiple islet cell carcinoma.

We reported a rare case of a 17-year-old female with pheochromocytoma associated with multiple islet cell carcinoma. Pheochromocytoma was identified in the right adrenal gland. Multiple pancreas tumours were demonstrated unpredictably in the diagnostic imaging of the pheochromocytoma. No other endocrinological neoplasm was observed in the pituitary, thyroid and parathyroid gland. The patient underwent right adrenalectomy and total pancreatectomy. Pheochromocytoma was benign, however, pancreas tumours were non-functioning islet cell tumours and histologically malignant. This combination is assumed to represent a mixed form of multiple endocrine neoplasia (MEN) 1 and MEN 2.

Adolescent↗

PubMedDate not supplied

Low density lipoprotein apheresis during cardiopulmonary bypass of hypercholesterolemic patients.

Ischemia-reperfusion injury in open heart surgery can cause atherosclerotic changes in both bypass grafts and native coronary arteries by increasing endothelial permeability and allowing excessive influx of LDL into the subendothelium. The authors used LDL apheresis during cardiopulmonary bypass (CPB) to actively remove serum LDL before reperfusion, minimizing LDL influx. They evaluated the efficacy and safety of this new procedure in eight hypercholesterolemic patients. The control group consisted of 41 patients. Mean LDL cholesterol (LDL-C) level on admission was 180 +/- 41 (SD) in the LA group and 139 +/- 32 mg/dl in the control group (p = 0.02). After 105 +/- 27 min of apheresis, the LDL-C level in the LA group decreased to 62 +/- 25 mg/dl (reduction rate: 59 +/- 18%). In contrast, in the control group, the LDL-C level was reduced to 117 +/- 41 mg/dl (reduction rate: 16 +/- 9.5% [P = 0.0001]) after CPB. No significant difference was observed in intraoperative blood loss, postoperative blood loss, platelet count, prothrombin time, activated partial thromboplastin time, incidence of wound complications, or early patency rate of bypass graft between groups. Low density lipoprotein apheresis during CPB is a safe and effective method for lowering serum LDL level sufficiently before reperfusion, and can adequately reduce LDL influx into the vessel wall.

Aged↗

PubMedDate not supplied

Thymic stromal cells eliminate T cells stimulated with antigen plus stromal Ia molecules through their cross-talk involving the production of interferon-gamma and nitric oxide.

We previously established a thymic stromal cell clone capable of inducing differentiation of immature thymocytes and described a clonal elimination model in which T cell clones are killed on the monolayer of this stromal clone by stimulation of their T cell receptors (TCR) with antigen plus stromal Ia molecules. This study investigated molecular mechanisms underlying this phenomenon. Antigenic stimulation on thymic stromal cells produced large amounts of interferon-gamma (IFN-gamma) and small amounts of tumor necrosis factor-alpha (TNF-alpha). Addition of anti-IFN-gamma monoclonal antibody (mAb) to these cultures largely prevented death of TCR-stimulated T cells. T cell death was also induced when cultures were treated with recombinant IFN-gamma (rIFN-gamma) or rTNF-alpha instead of the relevant antigen, showing that these lymphokines are involved in the process of T cell death. It was further demonstrated that these lymphokines, especially IFN-gamma, induced the expression of mRNA for the inducible type of nitric oxide (NO) synthase in thymic stromal cells and that enhanced levels of NO were produced by stromal cells cultures with T cells plus antigen or stimulated with rIFN-gamma or rTNF-alpha. NO was found to be critically responsible for inducing T cell death on the stromal cell monolayer following stimulation of T cells with antigen or of stromal cells with rIFN-gamma or rTNF-alpha, because T cells death was completely prevented by addition of NG-monomethyl-L-arginine (L-NMMA), which is capable of inhibiting NO production. These results indicate that elimination of TCR-stimulated T cells on thymic stromal monolayers with the capacity to support thymocyte differentiation is induced by the cross-talk between IFN-gamma/TNF-alpha-producing T cells and stromal cells capable of producing NO in response to these lymphokines.

Cell Communication↗

PubMedDate not supplied

Improvement of postoperative graft patency rate for coronary revascularization.

For coronary artery revascularization, the long term patency rate of internal thoracic artery (ITA) is excellent and arterial conduit for coronary bypass grafting (CABG) has been actively pursued. Application of the right gastroepiploic artery (GEA) is on the increase but, the patency of the GEA graft is more technically demanding than that of ITA. To improve early postoperative graft patency for coronary artery bypass grafting (CABG) for arterial graft, we modified the technique for anastomosis and demonstrated the patency by postoperative angiogram in 26 consecutive patients receiving CABG. The graft was anastomosed to the coronary artery using two 8-0. Prolene sutures for arterial graft and 7-0 Prolene sutures for saphenous vein (SV) graft. The heal and toe sides of the graft were sutured separately by the parachute technique (double parachute technique), followed by running suturing and typing at bilateral sides. The number of distal anastomoses was 3.4/patient and 44 arterial grafts and 40 SV grafts were used for coronary revascularization. Arterial grafts consisted of 33 ITAs, 9 GEAs, and two inferior epigastric arteries. The angiograms taken 10 to 14 days after operation demonstrated 100% patency rate of arterial grafts and 39 out of 40 SV grafts were patent. The overall patency rate in the early postoperative period was 98.8% The "double parachute" technique for CABG is highly accurate anastomosis with good visualization and the patency rates for all kinds of grafts were found to have improved.

Adolescent↗

PubMedDate not supplied

Laser scanning cytometry (LCS) allows detailed analysis of the cell cycle in PI stained human fibroblasts (TIG-7).

We have demonstrated a method for the in situ determination of the cell cycle phases of TIG-7 fibroblasts using a laser scanning cytometer (LSC) which has not only a function equivalent to flow cytometry (FCM) but also has a capability unique in itself. LSC allows a more detailed analysis of the cell cycle in cells stained with propidium iodide (PI) than FCM. With LSC it is possible to discriminate between mitotic cells and G2 cells, between post-mitotic cells and G1 cells, and between quiescent cells and cycling cells in a PI fluorescence peak (chromatin condensation) vs. fluorescence value (DNA content) cytogram for cells stained with PI. These were amply confirmed by experiments using colcemid and adriamycin. We were able to identify at least six cell subpopulations for PI stained cells using LSC; namely G1, S, G2, M, postmitotic and quiescent cell populations. LSC analysis facilitates the monitoring of effects of drugs on the cell cycle.

Cell Cycle↗