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Biomedical subjects

T Hirai

Publications and source records attributed to T Hirai.

At least 343 records · Page 19Linked to original sources
PubMed1993

Osteoporosis and reduction of residual ridge in edentulous patients.

The relationship between the height of the mandibular residual ridge and the severity of osteoporosis in elderly edentulous patients was investigated. The height of the mandibular residual ridge was measured by use of the mental foramen on panoramic radiographs. The severity of osteoporosis was determined by examining frontal and lateral radiographs of the vertebrae. All of the patients received a blood analysis. The correlation coefficient between age and the height of residual ridge was -0.38, which was statistically significant (p < 0.01). The residual ridge in women was lower than that of men, showing a statistical significance (p < 0.01). The correlation coefficient was -0.42 between degree of severity of osteoporosis and the height of the residual ridge, which was significant (p < 0.01). The parathyroid hormone level was high in the patients with a low residual ridge, and the calcitonin (CT) level was low. This study indicates that osteoporosis strongly affects reduction of the residual ridge in edentulous patients.

Age Factors↗
PubMed1993

Qualificated discrimination of ovarian malignancy by diagnostic ultrasound.

Ultrasonograms of 214 ovarian masses in 184 patients were studied to discriminate ovarian malignancies from benign masses and to help in developing a new scoring system using ultrasonographic findings with weight-adjusted scores. The 76 masses that showed cystic patterns only were directly determined to be benign, having an expected success rate of 97.4%. The remaining 138 masses, of which 116 showed mixed patterns and 22 of which showed solid patterns, were analyzed by the Quantification method No. 2 of Hayashi to select the effective ultrasonic findings and to obtain a good discriminant function. Eleven findings (items) expressing 29 categories were selected, and a discriminant function composed with a weight-adjusted score for each category was obtained as the result of the analysis. Using these functions, the 86.6% of the ovarian masses with mixed or solid patterns were correctly discriminated as being malignant, borderline-malignant, or benign. According to internal checks of all ovarian masses, the success rate was 90.2%. Then 73 ovarian masses of 65 new patients were discriminated as the external check, and a success rate of 93.2% was obtained. It is concluded that this newly developed scoring system using ultrasonic findings is useful in discriminating ovarian malignancies from benign ones.

Algorithms↗
PubMed1993

Comparative anatomical study of ventrolateral thalamic mass in humans and monkeys.

Cytoarchitecture and enzyme activity in the ventrolateral thalamic mass of humans and monkeys were examined using conventional Nissl, myelin stain and histochemical methods. According to the data obtained from cytometric analysis, the histogram patterns of cell dimensions and cell density in each ventrolateral thalamic nucleus in humans and monkeys were very similar. Moreover, acetylcholinesterase-stained sections revealed a parcellation of the ventrolateral thalamic nuclei that could be correlated with that in the monkey thalamus. Apart from differences of size, the nuclei of the human and monkey thalamus are remarkably similar. We proposed accordingly that a new parcellation of human thalamic nuclei be based on cytometric analysis and histochemical staining.

Acetylcholinesterase↗
PubMed1993

Tremor-mediating thalamic zone studied in humans and in monkeys.

The thalamic zone mediating the rhythmic burst activity related to the contralateral tremor was studied by microelectrodes in clinical cases with tremor and in monkeys with experimental tremor. The rhythmic burst time-locked with the tremor was found in a restricted area of the ventrointermedius nucleus (Vim) in humans and also in VPLo nucleus in monkeys. In both cases, only the lateral and ventrocaudal part of each nucleus, which was defined as the kinesthetic zone, was involved. A possible tremor-mediating neural circuit is postulated.

Animals↗
PubMed1993

Amelioration of post-ischemic lung reperfusion injury by prostaglandin E1.

To reduce ischemia-reperfusion injury, a number of clinical lung transplant programs employ prostaglandin E1 (PGE1) or prostacyclin (PGI2) before donor lung flush and harvest. The effect of prostaglandins on the reperfusion component of this ischemia-reperfusion complex is unknown. We investigated the effect of PGE1 given only during the period of reperfusion, on ischemic lung injury in an in situ rabbit model. To examine the mechanisms involved, we measured pulmonary hemodynamics as well as myeloperoxidase, circulating platelet, and tumor necrosis factor (TNF) values. Two hours of warm ischemia of the left lung was produced in anesthetized New Zealand white rabbits. The animals were randomly allocated into four groups based on treatment received only during reperfusion: PGE1, PGI2, nitroprusside (NP), or no treatment (controls). After 2 h of reperfusion, PaO2 in the PGE1 group was significantly higher (423 +/- 52.7 mm Hg) than in all other groups (PGI2, 239 +/- 43.4, p < 0.05; NP, 146 +/- 14.2 p < 0.01; controls, 74 +/- 19.1 mm Hg, p < 0.01), despite similar pulmonary vascular resistance in the PGE1 and NP groups. Although lower than in the PGE1 group, PaO2 in the PGI2 group was still significantly higher than that in controls. Wet/dry lung weight ratios were significantly lower in the PGE1 and PGI2 groups (6.5 +/- 0.2 [p < 0.01] and 6.9 +/- 0.6 [p < 0.05], respectively, versus 8.2 +/- 0.1 in controls). There were no significant differences in plasma TNF levels, platelet sequestration across the lungs, or lung myeloperoxidase activity in the four groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗
PubMed1993

Determinants of beneficial effect of heparin exercise treatment on treadmill capacity and long-term efficacy of the therapy in patients with chronic effort angina.

The purpose of the present study was to evaluate the factors which influence the effect of heparin exercise treatment on treadmill capacity, and to examine the long-term efficacy of the treatment in 16 patients with chronic effort angina. Treadmill exercise was performed 20 times for 2 to 3 weeks according to standard Bruce protocol. A single intravenous dose of heparin (5,000 IU) was given 10 min before each exercise period. Exercise with heparin pretreatment increased the total exercise duration from 6.6 +/- 1.6 (SD) to 9.4 +/- 1.9 min (p < 0.05) and the maximal rate-pressure product from 19,200 +/- 4,700 to 24,700 +/- 5,900 mmHg.beats/min (p < 0.05). The rate-pressure product at the onset of angina was also increased by 32% (p < 0.05). The ST segment depression at the same exercise time as in control exercise was ameliorated from 0.16 +/- 0.05 to 0.12 +/- 0.06 mV (p < 0.05). Multivariate analysis of the determinants of the effect of the treatment on treadmill capacity indicated that the treatment is more effective in patients without previous myocardial infarction. All of the above-mentioned variables of treadmill capacity did not change significantly during a follow-up period of 13 +/- 7 months (range; 4-24 months). These findings lend further support to heparin exercise treatment as a possible therapeutic approach in patients with chronic stable effort angina, and particularly in those without previous infarction.

Aged↗
PubMed1993

Prolonged lung allograft survival with a short course of FK 506.

We examined the hypothesis that FK 506 would induce graft acceptance after lung transplantation. Left lung allotransplantation was performed in size-matched mongrel dogs allocated to control (no immunosuppression, n = 3) and FK 506 (n = 5) groups. FK 506 (1.2 mg/kg intramuscularly every day) was given on posttransplantation days 0, 1, and 2. No other immunosuppressive agents were administered to either group. Chest x-ray and transplant lung physiologic assessments were performed on the fifth day and weekly thereafter. On day 29 an open lung biopsy and a third-party skin graft were performed. Lymphocytes were harvested and frozen from the recipient peripheral blood before transplantation and on days 8 and 29 afterwards for assessment in mixed lymphocyte reaction. Dogs were killed when their chest x-ray films showed allograft opacification or when the skin graft was rejected. Control lungs were all rejected after a median of 5 days. In the FK 506 group, one of five dogs aspirated during the fifteenth-day assessment and was killed, on the twenty-ninth day, because of severe rejection. At day 29, in the other four dogs, the transplanted lung yielded an arterial oxygen tension of 613 +/- 25 mm Hg (mean +/- standard deviation) and lung biopsy specimens showed no abnormalities histologically. These four dogs rejected third-party skin grafts after a median of 10 days. In two FK 506 dogs, mixed lymphocyte reaction at day 8 showed suppression of proliferation responses against donor and third-party lymphocytes. By day 29 responses against third-party lymphocytes had returned to almost preoperative levels, whereas antidonor responses were still suppressed. After skin graft rejection and killing, one of four dogs showed no sign of rejection, and the other three showed minimal to mild lung rejection at the time they were killed. We conclude that a 3-day course of 1.2 mg/kg of FK 506 induced prolonged graft acceptance after lung transplantation in dogs.

Animals↗
PubMed1993

Effect of preoperative irradiation on wound healing after bronchial anastomosis in mongrel dogs.

To determine the endurable radiation dose before bronchial anastomosis, the bronchial circulation of mongrel dogs was assessed after bronchoplastic surgery conducted after various single doses of radiation. Plastic surgery of the right main bronchus was carried out 1 week after cobalt 60 irradiation to the right hilar region. Bronchial blood flow was measured with laser Doppler velocimetry 7, 14, and 30 days after operation. Animals were killed 30 days after operation and the region of the bronchial anastomosis was examined histologically. The animals were divided into five groups: group A (control group without irradiation), group B (8 Gy irradiation), group C (16 Gy), group D (19 Gy), and group E (24 Gy). Wound healing of the anastomosed bronchus was excellent in groups A and B. In group A, bronchial blood flow did not drop below 80% of the preoperative level throughout the postoperative observation period. In group B, bronchial blood flow on day 7 after operation was only 65% of the preoperative level, but blood flow had returned to the preoperative level by day 30. In groups C, D, and E, bronchial blood flow was less than 60% of the preoperative level on day 30. There was a high prevalence of radiation-induced morbidity in the region of anastomosis in groups C, D, and E. Postoperative recovery of bronchial blood flow and wound healing of the anastomosed bronchus were thus delayed in dogs that had received high doses of radiation before operation. We conclude that the safe dose of preoperative radiation in clinically used fractionation is 36 Gy or less (corresponding to a single dose of 16 Gy or less in dogs).

Anastomosis, Surgical↗
PubMed1993

Potential errors in measuring the phase difference between chest flow and mouth flow.

We have previously reported that the phase difference between chest and mouth flows was a useful indicator of obstructive lung disease. In this paper, we calculated the effects of (i) airway reactance, (ii) extrathoracic airway shunt impedance, (iii) heating and humidification of the inspired air, (iv) abdominal gas volume, and (v) respiratory quotient on the measurement of the phase difference between chest flow (Vc) and mouth flow (Vm) using computer simulations. When the airway impedance was approximated as simple airway resistance, the phase difference (theta r) was calculated to be 0.8% less than the phase difference (theta s) calculated from the airway impedance (Za), including airway inertance and shunt compliance, in the normal lung. theta s became larger than theta r when the peripheral resistance increased, but did not exceed 5%. The extrathoracic airway shunt impedance effect did not exceed 0.1%, regardless of the respiratory frequency, airway impedance or thoracic gas volume. The influence of heating and humidification of the inspired air on the phase difference was calculated to be within 5%. The effect of abdominal gas was highly dependent on the abdominal gas volume and the respiratory pattern, but was calculated to be within 5%. The influence of the respiratory quotient was calculated to be negligible. As a result, it was concluded that none of the factors discussed above are an obstacle to the clinical application of this method for the evaluation of pathological changes in obstructive airway disorders.

Airway Resistance↗
PubMed1993

[Administration of human AT-III in a case of lupus anticoagulant positive pregnancy].

A 26-year-old pregnant woman was diagnosed as having both lupus anticoagulant (LA) and anticardiolipin antibody (ACA). Her previous pregnancy ended in intrauterine fetal death at 27 weeks' gestation. During the present pregnancy she was treated with aspirin, dipiridamole, predonisolone, and heparin. At 24 weeks, fetal growth became retarded, accompanied by markedly decreased activities of AT-III, protein C, plasminogen and alpha 2-plasmin inhibitor. Supplement of human AT-III led both to prolongation of the gestational period and improvement of fetal growth. The pregnancy ended in cesarean section because of signs of fetal distress at 30 weeks. The infant was a 1025-g male with Apgar scores of 5 and 9 at one and five minutes, respectively, and is healthy. The mother developed DIC after surgery, but recovered after therapy. In this case, TAT, alpha 2PI-plasmin complex, FDP Ddimer, FPB beta 15-42, L-FDP showed little correlation with the clinical course.

Adult↗
PubMed1993

[Surgical treatment of pulmonary arteriovenous fistula: report of two cases].

Two patients with surgical intervention for pulmonary arteriovenous fistula were presented. Lobectomy was performed in a cyanotic patient and fistula excision in another. To prevent the unsatisfactory prognosis of pulmonary arteriovenous fistula, surgical treatment is preferable to drug therapy when the diagnosis of this disease is established. The operative method should be selected according to the size, shape and localization of pulmonary arteriovenous fistula.

Arteriovenous Fistula↗
PubMed1993

[Schizophrenia following prenatal exposure to influenza during second trimester].

Mednick et al and O'Callaghan et al have recently reported that individuals exposed to the 1957 A2 influenza pandemic during their second trimester in utero are at risk for later schizophrenia. In this study, we determined whether their findings could be reproducible in a Japanese sample. In Japan, there were two waves of the 1957 A2 influenza pandemic; the first occurred from June to July, and the second from November to December. In addition, an epidemic of influenza A/B mixed type prevailed from January to February 1957. We obtained information on all dates of birth of 1187 individuals born between June 1955 and May 1960, who were treated for schizophrenia during the study period. November 1991 to September 1992, at 18 mental hospitals around Tokyo metropolitan areas. Hospital clinical diagnosis was used. We defined the index year from June 1957, beginning the first wave of the pandemic, to May 1958. We compared the number of schizophrenic births in each month of the index year with the average number of births in the corresponding month of the two years before, and following, the index year. The observed number of births in June 1957 and April 1958 were found to be significantly high compared with the average number of births for the corresponding month in the four control years. The 63% excess of schizophrenic births in June 1957 ensued about 5 months after the peak of influenza A/B mixed type epidemic; there was also 49% increase in births about 5 months after the second wave of the pandemic. Given that full term delivery occurred in our sample (ie, 9 months pregnancy), our results support the view of Mednick et al and O'Callaghan et al that maternal exposure to influenza in the mid-pregnancy increases the risk of developing schizophrenia.

Disease Outbreaks↗
PubMed1993

[A new operational method of functional neurosurgery combining micro-recording and MRI stereotaxy for the treatment of Parkinson's disease].

We have developed a new operational method for stereotactic functional neurosurgery using MRI stereotaxy combined with microelectrode recording. MRI stereotaxy shows us the individual variations of thalamic configurations. The tentative target points were determined using the MRI stereotaxy assisted software system which revised the distortion of MRI images. Consequently, the accuracy and safety of the microelectrode recording were increased. This, in turn, increased the accuracy of stereotactic thalamotomy while producing encouraging operational outcomes. The effectiveness of stereotactic thalamotomy for Parkinson's disease was confirmed by these excellent operative results. The symptoms improved and the dosage of medications, including L-DOPA, decreased. Furthermore, our results indicate that the distributing area of deep sensory neurons in the thalamus extended more posteriorly and upward than previously expected. Therefore, the functional and anatomical similarity between the human and monkey thalamus was reaffirmed. In this report, based on the above data, we reevaluated the neural mechanism of tremor and the role of stereotactic functional neurosurgery for Parkinson's disease.

Aged↗
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↗