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Biomedical subjects

T Hirai

Publications and source records attributed to T Hirai.

At least 361 records · Page 20Linked to original sources
PubMed1992

Significance of preinfarction angina for preservation of left ventricular function in acute myocardial infarction.

The effect of preinfarction angina on the preservation of left ventricular function was evaluated with the use of cineventriculography in 37 patients who had either total or subtotal occlusion of the proximal left anterior descending coronary artery during the convalescent period of myocardial infarction. In 15 patients who had preinfarction angina more than 1 week before the onset of acute myocardial infarction (group A), the global left ventricular ejection fraction was 54 +/- 3% (SEM) and regional wall motion in the infarct area was 10 +/- 3%. In 10 patients who had preinfarction angina occurred within 1 week before the onset of acute myocardial infarction (group B), the left ventricular ejection fraction and regional wall motion in the infarct area were 42 +/- 3% and 1 +/- 2%, respectively. In 12 patients without preinfarction angina (group C), the left ventricular ejection fraction and regional wall motion in the infarct area were 38 +/- 3% and -1 +/- 2%, respectively. In groups B and C, both the left ventricular ejection fraction and regional wall motion in the infarct area were lower than those in group A (p less than 0.05). The collateral circulation at the onset of acute myocardial infarction was better in group A compared with groups B and C (p less than 0.05). Thus the collateral circulation, promoted by repetitive anginal episodes indicative of myocardial ischemia, causes the preservation of myocardial function.

Angina Pectoris↗
PubMed1992

Isolation and characterization of goldfish cdk2, a cognate variant of the cell cycle regulator cdc2.

This paper reports the nucleotide and predicted amino acid sequences of the goldfish cdk2, a cognate variant of the cell cycle regulator cdc2. The predicted protein sequence shows strong homology to the other known cdk2 (88% for Xenopus and 90% for human). A monoclonal antibody against the C-terminal sequence of goldfish cdk2 recognized a 34-kDa protein in extracts from various goldfish tissues. The protein level was high in such tissues as testis and ovary containing actively dividing cells. Protein cdk2 binds to p13sucl, the fission yeast suc1+ gene product, but not to cyclin B, with which cdc2 forms a complex. The kinase activity of cdk2 increased 30-fold when oocytes matured, although its protein level did not remarkably change. Anti-cdk2 immunoprecipitates from 32P-labeled mature oocyte extracts contained a 47-kDa protein, which was not recognized by either anti-cyclin A or anti-cyclin B antibody, indicating complex formation of cdk2 with a protein other than cyclins A or B.

Amino Acid Sequence↗
PubMed1992

Purification and characterization of maturation-promoting factor in fish.

Maturation-promoting factor (MPF) activity has been demonstrated for the first time in fish oocytes. We purified MPF from a 100,000g supernatant of crushed, naturally spawned carp oocytes using four chromatography columns: Q-Sepharose Fast-Flow, p13suc1-affinity Sepharose, Mono S, and Superose 12. The final preparation was purified over 1000-fold with a recovery of about 1%. On Superose 12, MPF eluted as a single peak with an apparent molecular weight of 100 kDa. SDS-PAGE analysis of the active fractions after Superose 12 revealed the presence of four proteins of 33, 34, 46, and 48 kDa. A monoclonal antibody against the PSTAIR sequence of cdc2 kinase recognized the 33- and 34-kDa proteins for which the 46- and 48-kDa proteins are endogenous substrates. The 46- and 48-kDa proteins were recognized by a monoclonal antibody against Escherichia coli-produced goldfish cyclin B, but not by an anti-cyclin A antibody. When oocytes were matured in the presence of 32P, the labeling was seen with the 34-kDa protein, but not with the 33-kDa protein. The 34-kDa protein corresponded to the MPF activity, but the 33-kDa protein did not. These findings indicate that carp MPF is a complex of cdc2 kinase and cyclin B, and further that active MPF contains the phosphorylated form of cdc2 kinase.

Animals↗
PubMed1992

Increased bone volume and reduced bone turnover in vitamin D-replete rabbits by the administration of 24R,25-dihydroxyvitamin D3.

To study the effect of a large dose of 24R,25(OH)2D3 on bone metabolism, we treated vitamin D-replete rabbits with the agent for eight weeks. Fifteen rabbits 20 weeks of age were divided into three groups of five animals each. Group I received only the vehicle; groups II and III were given the agent at doses of 10 micrograms/kg/d, and 100 micrograms/kg/d, respectively. Through the dosing period, serum calcium, phosphorus, alkaline phosphatase, and creatinine levels were not altered. By the end of the experiment, serum 1,25(OH)2D or serum 25(OH)D levels did not change, nor did the PTH level. Serum 24,25(OH)2D levels for groups I, II, and III were 5.25 +/- 3.40, 76.16 +/- 19.90 (p less than .01), and 199.0 +/- 30.90 (p less than .01) ng/ml, respectively. The bone mineral content (BMC) significantly increased in group III. The percentages of BMC increase in group III over group I were 14.5% on the femur, 34.1% (p less than .01) on the sixth lumbar vertebra, and 23.3% (p less than .05) on the seventh lumbar vertebra. A marked increase of bone mineral densities in the cancellous bone-rich regions was seen in group III. Bone histomorphometry on the seventh lumbar vertebra demonstrated that both the eroded surface and the osteoclast number were reduced and the surfaces indicating bone formation such as the osteoid surface and the tetracycline double labeled surface were also reduced. However, both the osteoid thickness and the mineral apposition rate increased and the mineral formation rate at the tissue level remained approximately equal to that in the control.(ABSTRACT TRUNCATED AT 250 WORDS)

24,25-Dihydroxyvitamin D 3↗
PubMed1992

An experimental study of the flow-through venous flap: investigation of the width and area of survival with one flow-through vein preserved.

A quantitative analysis was undertaken to investigate the width and area of survival of flow-through venous flaps in 20 ears of 10 rabbits. The 3.0- x 3.0-cm flap models, which included one flow-through vein, were prepared with additional circulation from the graft bed and surrounding tissue excluded, as far as possible. The flaps were divided as follows: Group A--composite grafts (n = 10), and Group B--flow-through venous flaps (n = 10). All flaps in Group A became necrotic and all those in Group B showed partial survival along the flow-through vein. The average survival width was 1.10 +/- 0.48 cm, and the survival rate was 44 +/- 19.3 percent. Microangiograms revealed patency of the flow-through vein in all flaps of Group B. Histologically, there tended to be progressively more fibrous tissue in the area further away from the flow-through vein. The model is useful to investigate the width and area of survival in flow-through venous flaps.

Angiography↗
PubMed1992

Omentopexy for revascularization of free tracheal grafts in rats.

In rats, we examined the effect of an omentum wrapping on the vascularization of the trachea and on regeneration of the mucosal epithelium in the very early stage after free tracheal grafting. Two pieces of trachea were obtained from each donor rat. One piece was transplanted into the peritoneal cavity of the recipient rat and wrapped with omentum. The other piece was transplanted subcutaneously into the abdominal wall, without omentopexy. Recipients were sacrificed at random on days 1, 2, 3, and 4 after operation (5 rats/day). The increase of blood vessels rose significantly earlier in the omentopexy tracheas than in those without omentopexy (p less than 0.01), with all the former showing a normal ciliated, columnar epithelium in the membranous region of the trachea on day 4, accompanied by excellent epithelial regeneration in the cartilaginous region. These results suggest that omentopexy causes revascularization to occur earlier and to be completed in a shorter time, and that it also promotes epithelial regeneration following free tracheal grafting.

Animals↗
PubMed1992

Laser Doppler velocimetry measurement of canine mucosal circulation response to bronchial artery reperfusion after lung transplantation.

Left lung transplantation accompanied by reestablishment of the circulation of the bronchial arteries by simultaneous transplantation of part of the aorta was performed on seven dogs. Mucosal circulation of the bronchi at the anastomosis was evaluated using laser Doppler velocimetry (LDV). Since the donor lung must maintain blood supply through the bronchial arteries, the donor aorta from its ascending portion to the descending portion below the outlet for the last bronchial artery was retained with the lung graft. The distal end of the left brachiocephalic artery was sutured to the side of the recipient aorta when the blood supply to the bronchial arteries was to be restored. The LDV values before reperfusion of the bronchial arteries were 20 to 65% (mean: 42.8%) of the preoperative value. Since the LDV values increased to 36 to 125% (mean: 79.9%) of the control, blood flow to the bronchial mucosa increased evidently. Four out of seven dogs died one to two days after the operation due to bleeding and operative stress. One dog was sacrificed on the 4th postoperative day and another on the 16th. The last dog died 40 days after surgery. The unfavorable course of the LDV values in these three dogs suggest that the method used does not ensure an adequate blood supply to the bronchial arteries in the long term.

Animals↗
PubMed1992

Combination use of suboptimal dose of FK 506 and cyclosporine in canine lung transplantation.

The immunosuppressive potency and the side effects of combination therapy with FK 506 and cyclosporine A were studied in dogs that had undergone lung transplantation. The animals were divided into four groups: group A (one third optimal FK 506 dose: FK 506, 0.03 mg/kg intramuscularly) (n = 5), group B (one third optimal cyclosporine dose: cyclosporine 6 mg/kg orally) (n = 5), group C (one third FK 506 and one third cyclosporine optimal doses): FK 506, 0.03 mg/kg intramuscularly plus cyclosporine 6 mg/kg orally) (n = 5), and group D (half FK 506 plus half cyclosporine optimal doses: FK 506, 0.05 mg/kg intramuscularly, plus cyclosporine, 10 mg/kg orally) (n = 10). Assessments including chest x-ray film, fiberoptic bronchoscopy, hematologic and biochemical tests, FK 506 and cyclosporine blood trough level measurement, right pulmonary artery occlusion test, and histopathologic observations were performed. In group A two of five dogs survived 28 days and three died on postoperative days 7, 14, and 21. In group B one dog survived 28 days and four died on postoperative days 9 (two dogs), 14, and 21. Histologic examination showed severe rejection in both group A and group B. In group C all five dogs survived 28 days but showed mild rejection. In group D one dog died of intestinal bleeding on postoperative day 7 and nine survived 28 days. No pathologic changes were observed except in one case of mild rejection. The ventilation function of the transplanted lung was poor in groups A, B, and C but good in group D. No abnormal rise of FK 506 and cyclosporine trough levels was observed. There were no significant side effects and abnormal hematologic and biochemical data except in one dog in group D. We concluded (1) the combination of FK 506, 0.03 mg/kg, and cyclosporine, 6 mg/kg, is much more effective than either drug used singly, (2) the combination of FK 506, 0.05 mg/kg, and cyclosporine, 10 mg/kg, prevents rejection with tolerable side effects, and (3) no worse side effects are caused by combination therapy with FK 506 and cyclosporine than by either one used singly.

Animals↗
PubMed1992

Investigation of suitability of devascularized upper half of the whole stomach as replacement for the esophagus.

One hundred and fifteen patients with esophageal cancer underwent esophageal replacement with the stomach. The patients were divided into group A (52 patients, stomach tube, ante- or retro-sternal route) and group B (54 patients, devascularized upper half of the whole stomach, posterior mediastinal route). The post-operative complications, post operative symptoms and nutritional status were investigated in both groups. Lung complications tended to occur more frequently in group A (28.8% versus 22.2%), showing no significant difference. The incidence of other complications did not show a remarkable difference between either group except for leakage at the site of anastomosis. Major leakage occurred in 11.5% and 5.6%, and minor leakage in 30.8% and 18.5%, respectively. Postprandial fullness, nausea, heart burn and diarrhea were found to be somewhat higher in Group B. Change of oral intake, body weight and other indices of nutritional status were investigated and compared with pre- operative data. The amount of oral intake and levels of serum albumin was higher in group B than in group A between one and 12 months. These results demonstrate the superiority of the devascularized upper half of the whole stomach as an esophageal substitute.

Aged↗
PubMed1992

The immunosuppressive effect of FK 506 on canine lung transplantation.

The immunosuppressive potency of FK 506 was studied after left lung transplantation in adult mongrel dogs in comparison with cyclosporine. Fiberoptic bronchoscopy, bronchial mucosal blood flow measurement with laser Doppler velocimetry, and chest x-ray and pathologic examinations were performed. Group A had no immunosuppression (n = 5); group B received FK 506 (0.10 mg/kg/day intramuscularly (n = 5); group C received cyclosporine (20 mg/kg/day orally) (n = 5). In group A four dogs died of rejection on the seventh to the twenty-first postoperative days. Another one was killed on the fourteenth postoperative day because bronchial dehiscence occurred at the anastomosis. In group B one died of alveolar rejection on the seventh postoperative day. The remaining four survived 28 days and were put to death. In group C all five dogs survived 28 days and were put to death. In group A bronchial stenosis or dehiscence at the anastomosis was found in every one during the early postoperative period. In group B stenosis did not develop in any of the dogs, including the one that died on the seventh postoperative day. In group C slight stenosis was seen in one dog, severe narrowing in another, and good healing in the remaining three. The transplanted lungs were almost normal histologically in four animals of group B, and one showed alveolar phase rejection. In all animals of group A severe rejection was observed, and in group C two of five animals showed vascular phase rejection, two latent phase, and one fibrosis. Histologic examination of the bronchial anastomosis in group B showed almost normal bronchial epithelium and slight submucosal infiltration of mononuclear cells. In group A there was desquamation of epithelium and mild to moderate mononuclear cell infiltration. In group C hyperplasia of the epithelium was observed in two animals, an abscess at the site of anastomosis in one, and mild to moderate mononuclear cell infiltration in all five. With use of laser Doppler velocimetry, bronchial blood flow in group B was found to be the same as in group C. Laser Doppler velocimetry values reached preoperative levels by the twenty-eighth postoperative day in both groups. Although diarrhea developed in two dogs of group B, no other significant side effect of FK 506 was seen.

Animals↗
PubMed1992

Reliable thirty-hour lung preservation by donor lung hyperinflation.

We examined the hypothesis that the degree of inflation of the lungs at the time of harvest may have an important role in postpreservation function. Lungs of donor dogs randomly assigned to groups 1 (n = 5) and 2 (n = 5) were ventilated with large tidal volumes (tidal volume, 25 ml/kg; positive end-expiratory pressure, 5 cm H2O; respiratory rate, 12 breaths/min, inspired oxygen fraction 1.0) and were inflated to 30 cm H2O for 15 seconds before pulmonary artery flush and again immediately before tracheal crossclamping. In group 3 (n = 5) donor lungs were normally ventilated (tidal volume, 12.5 ml/kg, positive end-expiratory pressure 0 cm H2O; respiratory rate 12 breaths/min, inspired oxygen fraction, 1.0) and were not hyperinflated before pulmonary artery flushing; the trachea was crossclamped at end-inspiration. In groups 1 and 3 a large bolus (25 micrograms/kg) of prostaglandin E1 was injected into the pulmonary artery before flushing and was also added to the pulmonary artery flush solution (500 micrograms/L). A rapid (approximately 50 seconds), high-volume mm Hg), hypothermic (4 degrees C) pulmonary artery flush was performed in all hypothermic (4 degrees C) pulmonary artery flush was performed in all groups with modified Euro-Collins solution. Heart-lung blocks were stored at 4 degrees C for approximately 29 hours before left single lung allografting. An inflatable cuff was placed around the recipient right pulmonary artery, allowing independent study of the transplanted lung. Hyperinflated lungs harvested with or without prostaglandin E1 provided equivalently excellent early posttransplant function (arterial oxygen tension [mean +/- standard deviation]: group 1; 503 +/- 45, vs group 2; 529 +/- 150 mm Hg; inspired oxygen fraction 1.0). Mean arterial oxygen tension was significantly lower in group 3 (116 +/- 78 mm Hg) than in either groups 1 or 2 (p < 0.0002 for either comparison). Copious reperfusion pulmonary edema was a constant feature in group 3 but was not seen in groups 1 and 2. All 10 recipients in groups 1 and 2 survived the 3-day assessment period without difficulty; two of the five recipients in group 3 died during initial unilateral perfusion of the transplanted lung. Donor hyperventilation and inflation to 30 cm H2O before hypothermic storage can help provide excellent posttransplantation lung function after 30-hour preservation, with or without prostaglandin E1 pretreatment. We speculate that this improvement may be due to effects of increased lung volume on pulmonary vascular tone and/or surfactant metabolism.

Alprostadil↗
PubMed1992

[A comparative study with 5'-DFUR alone or in combination with tamoxifen (TAM) or medroxyprogesterone acetate (MPA) for advanced or recurrent breast cancer].

A comparative study of 5'-DFUR 600 mg/day alone (C-arm) or in combination with TAM 30 mg/day (A-arm) or MPA 600 mg/day (B-arm) was carried out. Thirty-four patients (aged 80 or less) with no prior treatment were evaluable, and the following results were obtained. 1) Patient characteristics were similar in each treatment group and the compliance in all groups was excellent. 2) The group B response rate (70.0%) was considerably higher than that of group A (23.1%) and C (27.3%). 3) In B, the response rates in soft tissues (80.0%) and bone (71.4%) were still good. 4) Mild side effects were encountered in about 15% of each group. We confirmed that combination chemotherapy with a low dose of 5'-DFUR and MPA was effective for first line treatment of metastatic breast cancer.

Adult↗
PubMed1992

[The neuroendocrine regulation of plasma corticosterone rhythm in rats].

The purpose of this study is to clarify the central mechanism of food-associated circadian oscillation whereby the prefeeding peak of plasma corticosterone was generated. Adults male rats were subjected to restricted daily feeding in which rats had free access to food at a fixed time of day. The developmental process, the oscillatory nature and the neuroendocrine control of the prefeeding corticosterone peak were investigated. The results were as follows: 1) The prefeeding corticosterone peak was established about one week after the start of restricted feeding. 2) The prefeeding peak persisted for at least 13 days even after the feeding schedule was terminated. 3) Corticotropin releasing hormone in the paraventricular nucleus (PVN) and the lower part of medial basal hypothalamus (MBH) decreased prior to daily feeding and increased postprandially under the restricted feeding. 4) Under restricted daily water supply with free access to food the prefeeding corticosterone peak was not as marked as under the restricted feeding. 5) Plasma arginine vasopressin (AVP) seemed not be involved in the generation of prefeeding corticosterone peak. 6) The prefeeding corticosterone peak failed to appear in the VMH-isolated rats in the dynamic phase, while it appeared in the static phase. These results indicate that the prefeeding corticosterone peak is regulated by an oscillatory mechanism, but are not consistent with the hypothesis that VMH is a site of the oscillation. The present results suggest that the energy state influences the expression of the prefeeding corticosterone peak.

Animals↗
PubMed1992

Neuropeptide release from the isolated, perfused, lower esophageal sphincter region of the rabbit and the effect of vasoactive intestinal peptide on the sphincter.

BACKGROUND: The aim was to evaluate the isolated, vascularly perfused, lower esophageal sphincter (LES) as a model for investigating the functional role of neuropeptides such as vasoactive intestinal peptide (VIP). METHODS: At laparotomy the LES was removed along with the distal esophagus, stomach, and left gastric artery and vein. The LES area, isolated from the body of the stomach by a custom-made clamp, was perfused with oxygenated Krebs-Ringer bicarbonate solution (pH 7.4, 38 degrees C) via the left gastric artery. The LES pressure was monitored continuously with a custom-made Dent sleeve catheter. LES pressure and release of neuropeptides were investigated after carbachol and VIP were administered alone or in combination. VIP, calcitonin gene-related peptide (CGRP), and somatostatin were measured in the venous perfusate collected from the left gastric vein. RESULTS: LES tone and contraction frequency were similarly increased by 10 and 100 nmol/L carbachol (increment, 4.0 +/- 0.26 mm Hg with 10 nmol/L carbachol; p less than 0.0003). Perfusion with 10 nmol/L VIP decreased basal tone and completely abolished the contraction induced by 100 nmol/L carbachol. VIP, CGRP, and somatostatin were released from the LES in response to 10 nmol/L carbachol (VIP rose from 55 +/- 13 to 179 +/- 24 pmol/L, CGRP, from 114 +/- 30 to 239 +/- 33 pmol/L, and somatostatin from 15 +/- 2 to 27 +/- 4 pmol/L; all p less than 0.001). CONCLUSIONS: These findings support a role for VIP in the inhibitory reflex of the LES but suggest that other neuropeptides may also be involved. The isolated, perfused LES provides a new tool for investigating neuropeptide interactions.

Animals↗
PubMed1991

Clinical significance of the expression of epidermal growth factor and its receptor in esophageal cancer.

The epidermal growth factor receptor (EGFR) level in 56 esophageal cancer tissues was measured by 125I-EGF binding assay to elucidate its role in tumor progression. The survival rate of patients with high EGFR level (more than 50 fmol/mg protein) was significantly lower than that of patients with low EGFR level (less than 50 fmol/mg protein, P less than 0.01), although a correlation between EGFR level and the pathologic findings was not observed. The expression of EGF was examined immunohistochemically using anti-EGF monoclonal antibody in 100 esophageal cancer tissues; EGF-positive tumor cells were detected in 92.0%. The immunoreactivity of EGF was classified arbitrarily into four grades according to the number of stained tumor cells. The expression of EGF significantly correlated with the differentiation of esophageal squamous cell carcinoma (P less than 0.01, by chi-square test). The survival rate of patients with high EGF immunoreactivity (Grade 2 or 3) was much lower than in those with lower grade (0 or 1) tumors, (P less than 0.01). Patients with both high EGFR level and EGF immunoreactivity had a much worse prognosis than if both were low. Furthermore, the mitotic index was higher in groups with both high EGFR and EGF than if both were low (16.39 +/- 5.35 versus 6.90 +/- 3.31). These results suggest that EGF and EGFR in the autocrine system may play an important role in tumor progression in esophageal cancer and their expression could be of prognostic significance.

Antibodies, Monoclonal↗