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Biomedical subjects

K Tsuboi

Publications and source records attributed to K Tsuboi.

At least 127 records · Page 7Linked to original sources
PubMed1986

Role of MLC serum inhibitory factors in high MLC-reactive kidney transplant recipients pretreated with donor-specific blood transfusion (DST).

In order to clarify the beneficial effect of donor-specific blood transfusions (DST) on kidney allograft survival, sera from 16 patients treated with DST were studied using the mixed lymphocyte culture (MLC) serum inhibition test. The results demonstrate that MLC inhibitory factors could be induced in the serum of the recipients after the completion of DST, and that these factors are directed against cells of the recipient but not against cell from the donor. Regarding the correlation with rejection episodes and clinical outcome, a significant improvement in renal transplant survival and reduction in rejection episodes was observed when MLC inhibitory factors were present in post-DST sera. These data suggest that such factors may contain antibodies directed against recognition sites on T lymphocytes, e.g., anti-idiotypic antibodies, and be associated with prolonged graft survival of living-related, high MLC-reactive one-haplotype-mismatched kidney.

Adult↗
PubMed1986

Lumbosacral extradural spinal arteriovenous malformation with blood supply from branches of internal iliac arteries.

A case of extradural spinal arteriovenous malformation (AVM) is described. The feeding arteries were branches from both internal iliac arteries. The pre-operative diagnosis was confirmed by myelography, selective angiography and plain and enhanced CT. The AVM was demonstrated in the ventrolateral epidural space by CT scan, providing an excellent pre-operative localisation related to dural sac and nerve roots. The clinical signs and symptoms are considered to originate from the venous congestion due to the high venous pressure caused by the AV shunt. The possible predisposing factors are also briefly discussed.

Angiography↗
PubMed1986

Regrowth patterns of supratentorial gliomas: estimation from computed tomographic scans.

To clarify the regrowth patterns of benign and malignant gliomas, we chose 27 intervals (between two operations or between an operation and autopsy) from 21 patients with pathologically verified recurrent supratentorial gliomas. Serial computed tomographic (CT) scans of these cases were analyzed to determine the doubling time (Td) calculated from the change in volume of enhanced and low density areas, the enhancement effect graded from 0 to 4 according to the Hounsfield number, and the presence of dissemination and contralateral extension. We studied 5 benign gliomas (including 1 case of radiation necrosis), 8 malignant astrocytomas, and 8 glioblastomas. The Td's of enhanced areas on CT scans of benign gliomas, malignant astrocytomas, and glioblastomas were 937 +/- 66.5 days, 65.1 +/- 29.4 days, and 48.1 +/- 20.9 days, respectively. The Td's of low density areas were 895 +/- 130.6 days, 70.8 +/- 22.2 days, and 50.5 +/- 14.7 days. There was a significant correlation between the Td's of the enhanced and low density areas (0.97). The enhancement effect increased at recurrence in 55% of the cases, with an average increase of 1.1 grades. The increase in enhancement effect at recurrence showed a tendency to become smaller as the tumor's degree of anaplasia increased. Radiotherapy was effective in significantly retarding the growth rate of malignant gliomas, whose Td's were doubled. Although the Td's of both enhanced and low density areas of benign gliomas were significantly longer than those of malignant gliomas, there was no significant difference in the Td's of enhanced areas between malignant astrocytomas and glioblastomas.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Beneficial effect of donor-specific blood transfusions (DST) on living-related kidney allograft survival.

The survival rate of 19 patients who underwent living-related kidney transplantation after donor-specific blood transfusions (DST) was compared with that of 32 historical controls receiving transplants without DST. The graft survival rate of the DST group was 82% after two and three years. The graft survival rate of the DST group was significantly better than the 53% rate after two years obtained with the 32 historical controls (p less than 0.05). We tested sera from 16 DST-treated recipients to study the beneficial effect of DST on kidney allograft survival using the mixed lymphocyte culture (MLC) serum inhibition test. The results demonstrated that MLC inhibitory factors were induced in the serum of the recipient after completion of DST. This inhibition of MLC was observed by treatment of responder lymphocytes with serum obtained three weeks after DST plus rabbit complement. The inhibitory effect was also specific for responder cells in anti-donor MLC. Regarding the correlation with rejection episodes, these MLC inhibitory factors were often observed in the non-rejection group (p less than 0.05). The data suggest that such factors may be anti-idiotypic antibodies and be associated with prolonged graft survival.

Adult↗
PubMed1986

Estimation of growth fraction with bromodeoxyuridine in human central nervous system tumors.

Twenty-five patients with tumors of the central nervous system received bromodeoxyuridine (BUdR), 200 mg/sq m, by intravenous infusion every 8 hours for 3 days before surgery. Excised tumor specimens were fixed in chilled 70% ethanol, embedded in paraffin, and cut into 6-micron sections. Each section was reacted with monoclonal antibodies against BUdR and stained with immunoperoxidase to identify nuclei that had incorporated BUdR. The growth fraction of each tumor was estimated by calculating the ratio of BUdR-positive nuclei to the total number of tumor cells in three to six microscopic fields in viable areas of the tumor. In seven cases, the tumor doubling time was measured from the serial computerized tomography scans and an attempt was made to estimate the cell cycle time. The growth fractions ranged from 9.1% to 46.5% in malignant gliomas, 2.0% to 6.7% in low-grade gliomas, 11.2% to 43.2% in metastatic brain tumors, 0.8% to 1.9% in pituitary adenomas, 3.9% to 4.6% in acoustic neurinomas, and 6.2% to 8.2% in meningiomas and cerebellar hemangioblastomas. The estimated cell cycle time was 5 to 12 days in most malignant gliomas and brain metastases; however, the actual cell cycle time should be substantially shorter because cell loss was not considered in the calculation. Although the growth fraction appeared to correlate with the biological malignancy of each tumor, the tumor doubling time did not reflect growth potential. It is possible that unpredictable cell loss plays an important role in tumor growth at certain sizes. Therefore, the cell cycle times calculated in this study are considerably overestimated and should be interpreted with caution.

Bromodeoxyuridine↗
PubMed1986

[Spinal epidural arteriovenous malformation fed by bilateral internal iliac arteries].

A rare case of a spinal epidural AVM fed by bilateral internal iliac arteries is reported. The patient was a 50 years old female with symptoms of slowly progressive paraparesis and sensory disturbance below L-2 associated with sphincter disorders. Myelography disclosed a serpiginous filling defect at the lumbar region. Selective internal iliac arteriograms disclosed an AVM fed by bilateral lateral sacral arteries. The nidus was excised totally, then a gradual improvement of those symptoms followed. Reviewing the literature, only 9 cases of spinal AVM of this type have been reported. In the majority of these cases, symptoms progressed slowly from the lower sacral level up to a level close to the end of the drainer. These symptoms were considered to be caused by steal phenomenon as well as by venous congestion due to arterialized intradural draining veins.

Arteriovenous Malformations↗
PubMed1986

[Cerebral venous thrombosis associated with the use of oral contraceptives].

The entity of cerebrovascular diseases associated with the use of oral contraceptives is well known but quite rare in Japan in contrast to Western countries. We recently encountered a 38 years old female with cerebral venous thrombosis considered to be caused by oral contraception. This patient took oral contraceptives for 17 days following therapeutic abortion, and was transferred to our hospital because of disturbed consciousness. CT scans disclosed a right temporo-occipital subcortical hemorrhagic infarction and bilateral thalamic infarction. Cerebral angiograms showed non-filling of cortical veins in the same area. The internal cerebral vein, vein of Galen and right transverse sinus were not visualized either. The hematoma and necrotic tissue were removed to avoid farther neurological deterioration. The brain was swollen and hyperemic, and thrombosed cortical veins were clearly recognized at operation. Twelve cases, including ours, of cerebrovascular diseases associated with oral contraception were reported up to now in Japan, and only 3 of them were diagnosed objectively as venous or sinus thrombosis. The average age of these 12 cases was 34 years old and many of them experienced abortion or therapeutic abortion. There was no relationship between the dose of estrogen and the onset of cerebrovascular diseases. We believe that the onset of this pathological state is based on gynecological hypercoagulable state, and the oral contraception may play a role of a trigger. Oral contraception should be contraindicated in patients with gynecological hypercoagulable state, hypertension and/or smoking habit.

Adult↗
PubMed1985

[The effects of TSH, cholera toxin and Graves' IgG on cAMP production in cultured human thyroid adenoma cells in monolayer].

Monolayer cultures of human thyroid cells derived from thyroid adenoma were utilized for the assay of thyroid stimulating substances such as thyrotropin (TSH), cholera toxin and thyroid stimulating immunoglobulin (TSI) in patients with Graves' disease. Adenoma cells were treated with 0.1% collagenase or 2000 unit/ml dispase to thyrocytes. The cells were cultured in MEM containing 10% fetal calf serum under an atmosphere of 5% CO2 in air. Within 24 hours, the cells attached themselves to the plastic surface and formed a monolayer. Cyclic AMP responses to TSH, cholera toxin or Graves' IgG were tested in a medium (PBS) containing 0.5 mM IBMX. The cyclic AMP responses to TSH were generally maximal on the 3rd day of culture and declined thereafter. The response was dose-dependent, and 10 microU/ml of TSH produced a significant increase of cellular cyclic AMP. The response by 1 microU/ml of TSH was 28 approximately 57 fold above the basal. The response was also a function of the incubation period. The maximal response was attained after 1 h incubation. When the cultures were washed after exposure to TSH, the cellular cyclic AMP levels rapidly declined, suggesting that removal of receptor-bound TSH results in a prompt cessation of cyclic AMP production. The thyroid cells in monolayer also responded to cholera toxin. The response was dose-dependent, and cholera toxin as low as 1 ng/ml was able to increase cyclic AMP production. In contrast to the observations in TSH, the cyclic AMP responses induced by cholera were hardly affected by washing the cultures after exposure to cholera toxin. Treatment of the cells with cholera toxin for only 3 min resulted in a continuous stimulation of cyclic AMP production for more than 4 hours. Confirming recent observations by others, most of Graves' IgG stimulated cyclic AMP production in a dose-dependent manner, but some of them inhibited the response at high concentrations. IgG derived from normal subjects did not increase cellular cyclic AMP. The time course in the cyclic AMP responses induced by Graves' IgG was variable among the IgG preparations from different patients. In some patients, the maximal responses were attained after 4 hours of incubation. A significant difference was noted between TSH and Graves' IgG in the stimulation of cyclic AMP production after washing the cultures. When the cultures were treated with Graves' IgG for 30 min, washed and then incubated without Graves' IgG, cellular cyclic AMP levels remained at the levels which were almost equivalent to those observed in the continuous presence of the IgGs.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenoma↗
PubMed1984

Accessory cerebral ventricle of the occipital lobe. Morphogenesis and clinical and pathological appearance.

Small separated accessory ventricles in the occipital lobe were observed in 21.3% of 404 patients, as seen by computerized tomogram. There was no significant preponderance in regard to sex or laterality. The accessory ventricles were clinically not significant. As seen at autopsy, accessory ventricles were found in the subcalcarine white matter, posterior to the occipital horn of the lateral ventricle, in 29.5% of 200 "normal" brains. Again, there were no significant sex and laterality differences. Accessory ventricles were never found in brains of fetuses or newborn babies. The youngest child in whom an accessory ventricle was found was 1 month old. No accessory ventricles were larger than 1 cm in diameter; they were slit-like, triangular or oval in shape. Histologically, they showed subtotal loss of the ependymal layer, subependymal gliosis, and/or fibrosis, and, in some cases, hyalinofibrotic capillary degeneration. Electron microscopy of the remaining ependymal cells in the accessory ventricle showed marked atrophy. Accessory ventricles are formed at the tip of the occipital horn postnatally through the expansion of the deep calcarine fissure, increase in brain volume in the region, and subsequent fusion of the mediolateral ventricular walls.

Adolescent↗