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T Hirai

Publications and source records attributed to T Hirai.

At least 19 recordsLinked to original sources
PubMed1992

M-phase-specific histone H1 kinase in fish oocytes. Purification, components and biochemical properties.

We demonstrate, for the first time in fish, that a Ca(2+)-independent and cyclic-nucleotide-independent histone H1 kinase activity oscillates according to the cell cycle of the oocyte, peaking at the first and the second meiotic metaphase with a transient drop between them. The kinase, M-phase-specific histone H1 kinase (M-H1K), was purified from mature carp oocytes by using two exogenous substrates for assaying its activity: histone H1 and a synthetic peptide (SP peptide, KKAAKSPKKAKK) containing the sequence KSPKK, which includes the consensus sequence of the site phosphorylated by a serine/threonine-specific protein kinase encoded by the fission yeast cdc2+ gene (cdc 2 kinase). The M-H1K and maturation-promoting factor (MPF) activities coincided closely throughout four steps of purification, strongly suggesting the identity of M-H1K and MPF. The final preparation was purified 5000-fold with a recovery of 4%, when histone H1 was used for the kinase assay, and 10,000-fold with a recovery of 7% when SP peptide was used. The purified molecular mass of the kinase was estimated to be 100 kDa by gel filtration and contained four proteins of 33, 34, 46 and 48 kDa. Anti-PSTAIR antibody recognizing cdc2 kinase cross-reacted with the 33-kDa and 34-kDa proteins, while the 46-kDa and 48-kDa bands cross-reacted with monoclonal antibodies raised against cyclin B. The 33-kDa protein was also recognized by an antibody against a goldfish cdk2 (Eg1) kinase, a cdc2-related kinase which has the PSTAIR sequence and binds to p13suc1 but does not form a complex with cyclin B. M-H1K activity corresponded well to the 34-kDa, 46-kDa and 48-kDa proteins but not to the 33-kDa protein. These results strongly suggest that M-H1K consists of cdc2 kinase forming a complex with cyclin B, and that cdk2 kinase is not a component of M-H1K, although it is found in the highly purified M-H1K. The purified M-H1K utilized Mg2+, Mn2+, ATP and GTP, and had a wide pH optimum ranging over 8.0-10.5. The kinase was thermolabile and sensitive to freezing/thawing.

Amino Acid Sequence↗
PubMed1992

Cyclin B in fish oocytes: its cDNA and amino acid sequences, appearance during maturation, and induction of p34cdc2 activation.

Under the influence of maturation-inducing hormone (MIH) secreted from follicle cells, oocyte maturation is finally triggered by maturation-promoting factor (MPF), which consists of a homolog of the cdc2+ gene product of fission yeast (p34cdc2) and cyclin B. Two species of cyclin B clones were isolated from a cDNA library constructed from mature goldfish oocytes. Sequence comparisons revealed that these two clones are highly homologous (95%) and were found to be similar to Xenopus cyclin B1. Using monoclonal antibodies against Escherichia coli-produced goldfish cyclin B and the PSTAIR sequence of p34cdc2, we examined the levels of cyclin B and p34cdc2 proteins during goldfish oocyte maturation induced in vitro by 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (17 alpha, 20 beta-DP), a natural MIH in fish. Protein p34cdc2 was found in immature oocyte extracts and did not remarkably change during oocyte maturation. Cyclin B was not detected in immature oocyte extracts and appeared when oocytes underwent germinal vesicle breakdown. Cyclin B that appeared during oocyte maturation was labelled with [35S]methionine, indicating its de novo synthesis. Introduction of E. coli-produced cyclin B into immature oocyte extracts induced p34cdc2 (MPF) activation. Although the possibility that immature goldfish oocytes contain an insoluble cyclin B is not completely excluded, these results strongly suggest that 17 alpha, 20 beta-DP induces oocytes to synthesize cyclin B, which in turn activates preexisting p34cdc2, forming active MPF.

Amino Acid Sequence↗
PubMed1992

Osteonal remodeling and mechanical properties of the femoral cortex in rabbits treated with 24R,25(OH)2D3.

The increase of bone mass by therapeutics does not always mean the enhancement of bone quality. The purpose of this study is to clarify the changes of osteonal remodeling and the mechanical properties of femoral cortex in rabbits treated with 24R,25(OH)2D3. Fifteen NZW rabbits (3 kg B.W.) were divided into three groups of 5 animals each. Groups 1, 2, and 3 were given vehicle, 10 micrograms/kg, and 100 micrograms/kg 24R,25(OH)2D3, respectively, daily for 8 weeks. At the end of the experiment, the left femur was removed and bone mineral content (BMC) was measured with single photon absorptiometry. Serum 24,25(OH)2D concentrations reached levels of approximately 15 and 200 times that of the controls in groups 2 and 3, respectively. Neither 25(OH)D nor 1,25(OH)2D level showed any significant change in either group. Group 3 showed significant increase in mineral content and density in the epimetaphyseal regions, but the increase at the diaphyseal region did not reach a statistically significant level. Mechanical test for torsion was conducted for mid-cortical regions. After the test, bone pieces were bonded together with adhesive to reconstruct the original form, and undecalcified cross-sectional sections were made at the diaphyses. Fluorescent microscopy disclosed a marked reduction of remodeling in secondary osteonal bone area. The numbers for double-labeled osteons for groups 1, 2, and 3 were 2.47 +/- 0.819, 1.14 +/- 1.02* and 0.137 +/- 0.307* N/mm2, respectively, and the numbers for osteons with resorption lacunae were 1.37 +/- 0.721, 0.412 +/- 0.370* and 0.268 +/- 0.339** N/mm2, respectively. However, neither structural stiffness nor strength correlated with the indices of osteonal remodeling; instead, they were significantly correlated with bone mineral contents.(ABSTRACT TRUNCATED AT 250 WORDS)

24,25-Dihydroxyvitamin D 3↗
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↗