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Biomedical subjects

Y Miyauchi

Publications and source records attributed to Y Miyauchi.

At least 55 records · Page 3Linked to original sources
PubMed1997

p53 mutation and absence of mdm2 amplification and Ki-ras mutation in 4-hydroxyamino quinoline 1-oxide induced transplantable osteosarcomas in rats.

Previously, we reported the establishment of two transplantable osteosarcomas, one induced by local application of a carcinogen, 4-hydroxyamino quinoline 1-oxide(4-HAQO), and another which developed spontaneously in rats, and their subdivision into four lines with high and low metastatic potential to the lung. In the present study, mutations of p53 and Ki-ras genes were investigated by PCR and SSCP followed by direct sequencing, and the amplification of the mdm2 gene was assessed by Southern blot analysis. Mutations of p53 in exon 7 were detected in 4-HAQO-induced transplantable osteosarcomas, but not their spontaneous counterparts, irrespective of the metastatic potentials. Direct sequencing revealed a CGC to CAC transition with an amino acid change of Arg to His, at codon 246. Neither Ki-ras mutations nor mdm2 amplification were detected in any of the transplantable tumors. The results suggest that while p53 mutations occurred during osteosarcoma development by 4-HAQO without mdm2 amplification and Ki-ras mutation does not contribute to osteosarcoma development in rats.

4-Hydroxyaminoquinoline-1-oxide↗
PubMed1997

Efficacy of CDDP and AGM-1470 chemotherapy against lung metastasis in rat osteosarcoma depends on the timing of combined administration.

The efficacy of combination therapy with cis-diammine-dichloroplatinum (II) (CDDP) and o-(chloroacetyl-carbamoyl) fumagillol (AGM-1470) was evaluated experimentally using a transplantable rat osteosarcoma line, previously established in our laboratory, with a high potential for metastasis. Tumor-bearing male Fischer 344 rats were administered CDDP (2.5 mg/kg) together with, or after discontinuation of, AGM-1470 treatment (10 mg/kg/body weight/week). When CDDP was administered three days after discontinuation of AGM-1470 the most pronounced antimetastatic effects were observed, although the antitumor effect was approximately the same.

Animals↗
PubMed1997

Vascularized fibular graft for reconstruction of the wrist after excision of giant cell tumor.

Seven patients with a giant-cell tumor involving the distal end of the radius were treated with en bloc resection and reconstruction with a free vascularized fibular graft. Two patients with stage 2 disease of Enneking's surgical staging and grade 2 of Campanacci's radiographic grading system were reconstructed with an articular fibular head graft. Five patients with stage 3 and grade 3 disease underwent wrist arthrodesis using fibular shaft transfer. There was radiographic evidence of bone union at the host-graft junctions in all cases. No local recurrence was seen in any of the patients at the most recent follow-up examinations. There were six good and one excellent functional results. Wrist arthroplasty using a vascularized fibula head graft is the best procedure for a stage 2 or grade 2 giant-cell tumor of the distal end of the radius. In cases of stage 3 or grade 3 disease, wrist arthrodesis using a vascularized fibular shaft graft is indicated.

Adolescent↗
PubMed1997

Curative percutaneous catheter ablation for various supraventricular and ventricular tachyarrhythmias. Results in 187 consecutive patients during the first five years.

Closed-chest transcatheter electrical ablation (catheter ablation) has been applied to various supraventricular and ventricular tachyarrhythmias as a radical therapeutic technique since its introduction in 1982. Currently, it has become a first line therapy for supraventricular tachyarrhythmias except atrial fibrillation and uncommon types of atrial flutter. We first carried out the ablation procedure in 1991 for the treatment of ventricular tachycardia. Up to February 1997, a total of 187 patients underwent catheter ablation in our institution. The aims of this study are to demonstrate our results of catheter ablation in the early 5 years and to show the usefulness of this new curative method. Successful results were obtained in 168 of 187 patients (overall final success rate: 89.8%). The success rates of each category of tachyarrhythmias were 100/105 patients (95%) with WPW syndrome, 41/46 (89%) with atrioventricular nodal reentrant tachycardia, 7/10 (70%) with atrial flutter, 4/4 (100%) with atrial tachycardia, 2/2 (100%) with medically refractory atrial fibrillation, 13/15 (85%) with idiopathic ventricular tachycardia and 3/7 (43%) with sustained ventricular tachycardia associated with structural heart disease, respectively. Complications that required invasive treatments were observed in 3 patients (2 hemopericardium and 1 complete atrioventricular block). Our results indicate that catheter ablation is highly effective in most categories of tachyarrhythmias and can be applied safely without lethal complications.

Adult↗
PubMed1997

Immunohistochemical study of extracellular matrices and elastic fibers in a human sternoclavicular joint.

In this study, we clarified the distribution of elastic and oxytalan fibers in a human sternoclavicular joint (SCJ) using a color image system and in extracellular matrices using immunoperoxidase staining. Fine elastic fibers (EFs) were scattered in the fibrous layer of the sternoclavicular disk. This articular disk was composed of a collagenous bundle on the sternum side of the articular disk in the SCJ and cellular components including connective tissue on the clavicular side of the articular disk. The thickness of the disk gradually increased from the inferior to superior portion. Collagen fibers type I, III and V and other extracellular matrices (ECMs) were detected in the hypertrophic zone in the clavicular and sternum side of the SCJ and in the connective tissue of the articulatio condylar. On the cervical surface of the articular disk, cellular activity was higher than on the sternum surface.

Adult↗
PubMed1997

[Total intravenous anesthesia with propofol and fentanyl for laparoscopic cholecystectomy].

The postoperative antiemetic effect of total intravenous anesthesia with propofol and fentanyl was evaluated in 40 patients for laparoscopic cholecystectomy. Patients were divided into 2 groups. In group P, anesthesia was induced with intravenous fentanyl 0.1 mg and propofol 2 mg.kg-1 and maintained with continuous infusion of propofol. In group I, anesthesia was induced with intravenous thiopental 5 mg.kg-1 and maintained with nitrous oxide 60% in oxygen and isoflurane. Post-operative nausea and vomiting were recorded for 8 h after surgery. Nausea scores (range 1-4) were significantly lower in group P as compared with group I at 0 h after surgery, but no difference between the groups at 2 h, 4 h, 8 h after surgery. No significant differences were found in the incidence of vomiting between the groups. These results suggest that total intravenous anesthesia with propofol and fentanyl is superior to inhalational anesthesia with nitrous oxide and isoflurane in postoperative nausea. This antiemetic effect is, however, limited in the early period after anesthesia.

Aged↗
PubMed1996

Inflammatory reactions after vascular prosthesis implantation: a comparison of gelatin-sealed and unsealed Dacron prostheses.

Despite widespread use of the gelatin-sealed knitted Dacron prosthesis (GDP) in clinical practice owing to its zero porosity, the biological impacts of this graft are still controversial. We conducted a randomized controlled study on 50 patients undergoing abdominal aortic aneurysm repair to evaluate the inflammatory reaction to GDP (n = 25) and unsealed knitted Dacron prostheses (UDP, n = 25). There were no significant differences in the mean age, size of the aneurysm, operative time, blood loss, or transfusion requirements between the GDP and UDP groups. During the first 7 postoperative days (PODs), slight fever and leukocytosis were noticed in both groups. Significant differences in maximum body temperature, leukocyte count, and plasma C-reactive protein concentration were observed between the GDP and UDP groups on POD 14:37.2 +/- 0.5 degrees C vs 36.9 +/- 0.3 degrees C (P = 0.019), 8,151 +/- 1,788/microliters vs 6,914 +/- 1,501/microliters (P = 0.015), and 32.6 +/- 27.5 mg/l vs 19.0 +/- 15.8 mg/l (P = 0.048), respectively. By POD 21, however, there were no detectable differences in these variables. Thus, we concluded that GDP caused an inflammatory reaction in the 2nd week after implantation, but ultimately there were no significant differences from UDP by the 3rd week.

Aged↗
PubMed1996

Hereditary partial deficiency of plasminogen activator inhibitor-1 associated with a lifelong bleeding tendency.

We report a family with a partial deficiency of plasminogen activator inhibitor-1 (PAI-1). The affected family members had had lifelong bleeding episodes, such as rebleeding after tooth extraction and trauma. This bleeding tendency in the propositus was autosomally transmitted from grandfather to son. The characteristic abnormalities of fibrinolysis in the patients were shortened eugloblin lysis time, low PAI activity with low antigen levels of plasminogen activator inhibitor-1 in plasma and serum. Furthermore, plasma 'active PAI' which indicates the quantity of plasminogen activator inhibitor-1 bound with plasminogen activator added was very low in these patients. These parameters were markedly low after the venous occlusion test. Moreover, two of the affected members had a much lower level of platelet PAI-1 than the normal controls. Tranexamic acid (Transamine) was useful to control bleeding in these patients.

Adolescent↗
PubMed1996

Involvement of Fyn tyrosine kinase in progression of cytokinesis of B lymphocyte progenitor.

We analyzed the role of Fyn tyrosine kinase in cell cycle progression of B lymphocyte progenitor (pro B cell). Whereas there were no substantial defects in the intramarrow B cell genesis in the fyn(-) mouse, and long-term proliferation of fyn(-) pro B cells was maintained in vitro under a serum containing culture condition, the cell cycle was arrested at G2/M upon serum deprivation. Morphological analyses demonstrated that the cytokinesis of fyn(-) pro B cells was retarded in the presence of serum and that the entry of fyn(-) pro B cells into late telophase was completely blocked under the serum-free condition. In contrast, the earlier phases of mitosis of fyn(-) pro B cells proceeded normally without FCS. This failure to initiate late telophase resulted in the accumulation of elliptical binucleated cells that might be the outcome of the nuclear division without cytokinesis. Consistent with this defect in the progression of cytokinesis, Fyn was localized in the midspace of dividing pro B cells at anaphase. These results suggested that Fyn localizes at the midspace of dividing pro B cells and regulates the progression of cytokinesis.

Animals↗
PubMed1996

Effects of biliary obstruction on the endocytic activity in hepatocyte and liver sinusoidal endothelial cells in rats.

Obstructive jaundice impairs function in liver parenchymal and sinusoidal cells. In this study, the endocytic activity in sinusoidal endothelial cells in the rats with biliary obstruction was measured by plasma clearance of radiolabeled formaldehyde-treated bovine serum albumin. The endocytic activity in hepatocytes was also measured with asialofetuin. The clearance of asialofetuin significantly decreased after 1 week of biliary obstruction and the clearance was reduced to 42% of the controls at 4 weeks. In contrast, the clearance of formaldehyde-treated bovine serum albumin was essentially unchanged until 4 weeks of biliary obstruction. The maximal removal rate which was assessed by kinetic analysis of injected protein for formaldehyde-treated bovine serum albumin showed no significant decrease at 2 weeks compared with the controls, while that for asialofetuin was significantly decreased to 50% of the controls. These results suggest that the endocytosis of formaldehyde-treated bovine serum albumin in endothelial cells is maintained until the advanced stage of biliary obstruction, whereas the endocytic activity for asialofetuin in hepatocytes is impaired earlier.

Animals↗
PubMed1996

Slowing of peripheral motor nerve conduction was ameliorated by aminoguanidine in streptozocin-induced diabetic rats.

The aims of this study were to investigate the effect of aminoguanidine (AG) on slowing of motor nerve conduction velocity (MNCV) of the sciatic nerve in streptozocin-induced diabetic rats and to assess its mechanism of action. The MNCV of the sciatic nerve was measured electrophysiologically in diabetic rats treated with and without AG for 16 weeks. To elucidate the action of AG, morphological lesion and abnormality of polyol pathway metabolism in the nerve were examined and tissue levels of advanced glycosylation end-products (AGE) were determined as an indicator of AGE accumulation in tissue. Diabetic rats were treated with AG at three doses of 10, 25 and 50 mg/kg for 16 weeks. Myelinated fiber morphometry and nerve Na+,K(-)-ATPase activity were determined. The AGE levels in renal cortex were measured by a specific ELISA. Aminoguanidine dose-dependently ameliorated slowing of MNCV 16 weeks after the treatment without changing body weight or blood glucose levels. No difference in myelinated fiber morphometry or Na+,K(+)-ATPase activity with or without AG treatment was detected in diabetic rats. Diabetes increased the AGE level in the renal cortex by six times compared to non-diabetic rats, and AG reduced the rise in the AGE level by 40%. The MNCV was inversely correlated with the AGE levels. We conclude that improvement of conduction slowing by AG in experimental diabetes may be through decreasing the AGE level in the peripheral tissues. Aminoguanidine may have a therapeutic potential in controlling diabetic peripheral neuropathy.

Animals↗
PubMed1996

Pituitary apoplexy after subtotal thyroidectomy in an acromegalic patient with a large goiter.

A case of pituitary apoplexy occurring after subtotal thyroidectomy in an acromegalic woman with a large adenomatous goiter is described. The patient had severe apnea because the large goiter was causing airway compression. Prior to the planned hypophysectomy, a subtotal thyroidectomy was performed to relieve tracheal stenosis. Shortly after the operation, the patient developed a headache that lasted for several days. The serum levels of growth hormone and somatomedin-C spontaneously normalized seventeen days after this episode and have remained normal for two years. Pituitary apoplexy was thought to have caused the observed results without deterioration of the pituitary function.

Acromegaly↗
PubMed1996

Oxygen metabolism after cardiopulmonary bypass.

We hypothesized that the relationship between oxygen delivery (DO2) and oxygen consumption (VO2) in patients undergoing cardiopulmonary bypass (CPB) may differ from the normal physiologic state because of oxygen debts acquired during CPB. Blood gas analysis and hemodynamic parameters were repeatedly measured for determination of DO2 and VO2 in 40 patients undergoing CPB every 8 hours during the first 48 hours postoperatively. Twenty patients of acute myocardial infarction (AMI) also were studied in the same protocol as controls. In the CPB group, a regression analysis showed that VO2 was significantly dependent on DO2, even within the physiologic range of DO2 (>500 ml/min/m2); VO2=121+0.0844 DO2 (R=0.25, p=0.023). However, such supply-dependent oxygen consumption was not observed in the AMI patients. Perioperative parameters which had a significant relationship with oxygen extraction rate (VO2/DO2 x 100) were Hb concentration, cardiac index, systemic vascular resistance, age of the patients, duration of CPB, SaO2 and SvO2. These results suggest that patients undergoing CPB need a much higher oxygen supply to recover from the oxygen debt during open heart surgery.

Cardiopulmonary Bypass↗
PubMed1996

[A device for rapid elevation of plasma methotrexate (MTX) concentration and its maintenance in high-dose MTX therapy].

For 5 osteosarcomas and one synovial sarcoma, 24 courses of high-dose methotrexate (MTX) therapy were performed. At MTX doses of 300 mg/kg with several infusion patterns, the plasma MTX concentrations were measured by fluorescence polarization immunoassay. In the various types of infusions, five hours oblique and five hours bolus infusions were well maintained at 1,000 micromol/l for several hours. In particular, five hours bolus infusion of MTX needed only 20 minutes to reach 822 micromol/l and maintained 1,000 micromol/l during almost the entire infusion period. Optimization of chemotherapy for sarcomas by MTX requires individual adaptation of the infusion pattern.

Adolescent↗
PubMed1996

Dilation of gelatin-sealed knitted dacron prosthesis.

OBJECTIVE: Postoperative dilation of gelatin-sealed knitted dacron prostheses (Gelseal, Vascutek, Scotland UK) was studied. EXPERIMENTAL DESIGN: Prospective study. SETTING: Institutional clinical research. MATERIALS AND METHODS: Ten patients who underwent aortic repair for abdominal aortic aneurysm (AAA) with the Gelseal graft were studied (Group A). Prior to and immediately following the implantation, the diameter of Gelseal was measured with slide calipers. The external diameter was examined by CT scan 4 weeks following the surgery. Another 10 patients, who had undergone AAA repair with the Gelseal graft more than 2 years earlier (Group B), also were examined by CT scan. Early and late dilation of Gelseal was estimated and the data from the two groups were compared. MEASURES: In Group A, the preimplantation external diameter was 22.6 +/- 2.3 mm while the mean package size (PS) used was 18.7 +/- 2.1 mm prior to implantation. Just after the implantation, the external diameter changed to 22.7 +/- 2.4 mm. Four weeks later, it averaged 24.0 +/- 2.2 mm. In Group B, the PS averaged 19.2 +/- 2.0 mm, while the external diameter measured by CT scan averaged 27.8 +/- 3.4 mm at a mean of 31.3 months following the surgery. RESULTS: Prior to implantation, the external diameter was 1.21 times that of the PS. Following implantation, it was 1.21 times (immediately after), 1.28 times (4 weeks later), and 1.45 times (31.3 months later) of the PS. CONCLUSIONS: At an average of 31.3 months following implantation, the external diameter was 45% larger than the PS. Considering that the external diameter was 21% larger than the PS even prior to implantation, the actual dilation rate is estimated as 24% of the PS in the late postoperative period.

Aged↗
PubMed1996

[Treatment of postoperative nausea and vomiting with ondansetron in patients administered anti-neoplastic agents].

The antiemetic effect of ondansetron (a 5-HT3 antagonist) was evaluated in patients treated with intraperitoneally administered anti-neoplastic agents (cisplatin and mitomycin-C) during surgery for ovarian cancer. Anesthesia was induced with intravenous thiopental 5 mg x kg-1 and maintained with nitrous oxide 66% in oxygen and isoflurane. After surgery, 6 patients received a single intravenous dose of ondansetron 4 mg (group O), 6 others did not receive ondansetron (group C). Both groups received an intravenous dose of methyl-prednisolone 500 mg. An intravenous dose of metoclopramide 10 mg was provided in case of continued vomiting or at the patient's request as a rescue antiemetic. The incidence of vomiting was 13% in group O and 87% in group C (P < 0.05). Nausea scores (range 1-4) were significantly lower in group O as compared with group C at 4 h and 8 h after surgery. Total dose of metoclopramide was 20 +/- 13 mg (mean +/- SD) in group C and 2 +/- 4 mg in group O. Administration of anti-neoplastic agents during surgery caused severe nausea and vomiting after surgery and ondansetron prevented the occurrence of nausea and vomiting almost completely. We conclude that ondansetron is an effective antiemetic for preventing postoperative nausea and vomiting in patients administered anti-neoplastic agents.

Adult↗
PubMed1996

Fundamental study of the relationship between the lateral mandibular position and the bulging of the temporal muscle region.

Greene proposed a temporal-muscle-gripping method to judge the suitability of the mandibular position by gripping the temporal muscle region. Ogiwara examined the relationship between the anteroposterior mandibular position and the bulging of the temporal muscle region. However, the relationship between the lateral mandibular position and the bulging of the temporal muscle region has not been clarified. In this study, the relationship between the lateral mandibular position and the bulging of the temporal muscle region was examined. Five dentulous subjects were required to occlude at the tapping point and laterally deviated mandibular positions from the tapping point. The bulging of the temporal muscle region was measured at each mandibular position. Results were as follows. The bulging of the temporal muscle region at occlusion was influenced by lateral deviations in the mandibular position. The bulging was larger and started earlier on the deviated side than on the opposite side. In the measurement of the starting time of bulging of the temporal muscle region, the value of the difference in the starting time of bulging between the right and the left side at more than 0.4 mm lateral deviated mandibular position was larger than the value of the difference in the starting time of bulging between the right and the left side at the tapping point in all five subjects (p < 0.05).

Adult↗