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Biomedical subjects

T Doi

Publications and source records attributed to T Doi.

587 records · Page 33Linked to original sources

Banded chromosome study of the Iriomote cat.

The G-banded karyotype of the Iriomote cat, Felis iriomotensis, was found to be indistinguishable from that of F. bengalensis, F. viverrinus, and F. concolor. The karyotype of these four cats is, however, distinguishable from karyotypes of all other species of cats whose chromosomes have been studied. Silver-staining showed nucleolar organizing regions on the satellited stalks of the E1 chromosomes. Based on morphological and cytogenetic parameters F. iriomotensis is probably most closely related to F. bengalensis, the only other wild felid native to Japan.

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Expression of the amino terminal part of synthetic human growth hormone gene and somatomedin-like activity of expressed protein.

We have constructed three different plasmids containing parts of the human growth hormone gene using chemically synthesized oligomers and cloned them for the purpose of expressing them in Escherichia coli. AB, B and BC gene segments corresponding to ABhGH (residue 1-138), BhGH (residue 44-138) and BChGH (residue 44-192) were placed under the control of a tryptophan promoter in the expression vector. Upon induction with 3-indolylacrylic acid, ABhGH accumulated in cells but the BhGH and BChGH segments were not detected appreciably. Northern blotting analysis showed that the amount of mRNA transcribed from the AB gene segment was about ten-fold higher than that from the B or BC gene segment. ABhGH was found to have insulin-like growth factor I (IGF-I) activity, which could be explained by the hydrophilicity curves of these proteins.

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White matter hyperintensities may correspond to areas of increased blood volume: correlative MR and PET observations.

A method for correlating positron emission tomography with magnetic resonance (MR) imaging enabled the authors to examine the high intensity white matter areas in T2-weighted images in patients with internal carotid artery occlusion. The high intensity areas showed increased cerebral blood volume compared with the ipsilateral and contralateral normal intensity white matter. This observation may have relevance in explaining some of the patchy white matter lesions seen in MR images.

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Isolation of Guinea pig inner hair cells using manual microsurgical dissection.

Cochlear inner hair cells (IHCs) and outer hair cells (OHCs) show distinctive morphological features that are usually sufficient to distinguish these two species in vitro. However, OHCs may sometimes resemble IHCs when they are mechanically distorted or begin swelling at their basal end. As a result, accurately discriminating the cells based on morphology was thought to be problematic. An objective method that allows us to clearly and unambiguously distinguish these two cell types is therefore of continued interest. We describe a protocol in which solitary IHCs were harvested from guinea pig cochlea using a manual microsurgical dissection.

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Pitavastatin prevents bacterial translocation after nonpulsatile/low-pressure blood flow in early atherosclerotic rat: inhibition of small intestine inducible nitric oxide synthase.

BACKGROUND: Cardiopulmonary bypass decreases intestinal mucosal blood flow because of nonpulsatile and low-pressure blood flow resulting in bacterial translocation (BT) and atherosclerosis also has peripheral blood flow deficiency. The risk of nonpulsatile and low-pressure blood flow for atherosclerotic animals and the effect of statin administration, which has pleiotropic effects, were studied. METHODS: Wistar rats were divided into four groups: group N (normal diet), group C (high-cholesterol diet), group S (group C plus pitavastatin therapy), and group I [group C plus inducible nitric oxide (iNOS) inhibitor therapy]. First of all, vascular responses were measured. Then the rats underwent nonpulsatile/low-pressure blood flow in the intestine, and the serum peptidoglycan concentration as a parameter of BT, the small intestinal PO(2) ratio (intestinal PO(2)/PaO(2)) as a parameter of mucosal blood flow, and NO concentrations were measured before surgery (T0), at the end of 90 min of stenosis (T1), and 90 min after the release of stenosis (T2). Immunostaining for nitrotyrosine was also performed at T2. RESULTS: Group C had vascular endothelial dysfunction without histological changes, which indicated early atherosclerosis. The serum peptidoglycan concentration increased significantly at T2 only in group C. The intestinal PO(2) ratio was decreased at T1 in all the groups, and retuned to baseline at T2 in group N and group S, but not in group C or group I. Jejunal NO only in group C was significantly higher at all time points and ileal NO production at T1 and T2. There tended to be a positive stain for nitrotyrosine along the mucosal epithelium in group C. CONCLUSION: In the setting of early atherosclerosis, intestinal blood flow does not only improve after nonpulsatile/low-pressure blood flow but causes BT because of a large amount of NO from high enzymatic intestinal iNOS activity, and pitavastatin treatment can prevent BT by improving both issues.

Animals↗

Case report: spontaneous hemangiosarcoma in the pancreas of a Fischer rat.

Spontaneous hemangioma or hemangiosarcoma is sometimes found in the viscera and soft tissue of rats and mice. However, there is no report of the tumor occurring in the pancreas of rats. We report a pancreatic hemangiosarcoma in a 109-wk-old, male Fischer 344 rat, which was used in the control group of a carcinogenicity study. The tumor destroyed and compressed the normal pancreatic tissue and displayed a high density in terms of the numerous capillaries and strands of endothelial tumor cells. A reticulin stain revealed a dense network formation. The frequency of proliferating cell nuclear antigen-positive staining showed active proliferation of the tumor cells. Immunohistochemically, some of the tumor cells stained positive with factor VIII-related antigen, and ultrastructurally, Weibel-Palade bodies were rarely observed in the cytoplasm of the tumor cell. From these findings, the tumor was diagnosed as a hemangiosarcoma that occurred naturally in the pancreas.

Animals↗

[A case of Churg-Strauss syndrome which cheaf complain was gross hematuria].

We report a case of Churg-Strauss syndrome complaining of gross hematuria. A 74-year-old man was admitted to our hospital for further examination of gross hematuria. Abdominal CT and retrograde pyelography revealed left renal pelvic tumor, and left nephrectomy was performed. There was no tumor, but submucous hemorrhage was seen in the renal pelvis. The histopathologic diagnosis was allergic granulomatous angitis. The administration of prednisolone was done, but he suddenly died of acute heart failure after 1 month postoperatively.

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Efficacy of a biomechanical counterpulsation device powered by skeletal muscle for right heart assist.

A valveless, single-orifice counterpulsation device powered by skeletal muscle was applied to the pulmonary artery for right heart assist. Latissimus dorsi muscles of six dogs had been electrically conditioned for four months in advance (Group 1); the muscles of eight dogs were not preconditioned (Group 2). A polyvinyl chloride balloon was placed beneath the latissimus dorsi muscle and connected to the left pulmonary artery using a noncollapsing graft. Latissimus dorsi muscle was paced synchronously to the cardiac cycle to produce pulmonary artery diastolic augmentation. Percent changes in diastolic augmentation pressure (% DAP) in the main PA was measured. Percent DAP after 180 min assistance was 91 +/- 10% in Group 1, whereas it decreased to 17 +/- 12% in Group 2 (p less than 0.001). These results demonstrate that electrically conditioned skeletal muscle is effective as a power source in right heart assist.

Animals↗

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.

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