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Biomedical subjects

K Oka

Publications and source records attributed to K Oka.

At least 289 records · Page 16Linked to original sources
PubMed1994

Obstruction of the superior sagittal sinus caused by parasagittal meningiomas: the role of collateral venous pathways.

The authors present studies of eight patients who had obstruction of the superior sagittal sinus caused by parasagittal meningioma. The results indicate that meningeal veins and end-to-end anastomoses of the superficial veins of the cerebrum play important roles as collateral venous pathways. This assessment suggests that, in patients with obstruction of the superior sagittal sinus, venous phase angiography should be carefully interpreted before surgery is attempted for parasagittal meningiomas.

Cerebral Angiography↗
PubMed1994

[Localization of platelet-derived endothelial cell growth factor in human glioblastoma and meningioma].

Localization of platelet-derived endothelial cell growth factor (PD-ECGF) in the surgical specimens of 11 human glioblastomas and 12 meningiomas was immunohistochemically examined with a polyclonal anti-PD-ECGF rabbit IgG. PD-ECGF was mainly localized in macrophages distributing around blood vessels at the peripheries of tumor tissue, especially of glioblastoma. PD-ECGF-positive macrophages were frequently accumulated in the vascular-rich stroma of glioblastoma, where occasionally expressed proliferating cell nuclear antigen-positive endothelial cells. However, few macrophages expressing PD-ECGF were scatteringly seen in meningioma. These findings suggest that PD-ECGF plays an important role in the growth of glioblastoma by affecting the stromal angiogenesis.

Brain Neoplasms↗
PubMed1994

Cytoplasmic p105 index is an accurate mitotic index, but is not related to prognosis in cervical carcinoma.

The monoclonal antibody p105 (clone 780-3) recognizes proliferation-associated nuclear antigen p105 in conventionally fixed and processed histological materials. Formaldehyde solution-fixed and paraffin-embedded specimens excised from 184 patients with stage III squamous cell carcinoma of the cervix who were treated with radiation therapy alone were investigated for p105 positivity using an immunohistochemical method. Mitotic cancer cells were strongly positive for p105, showing cytoplasmic p105 positivity in almost all cases. The mean cytoplasmic p105 index was 2.02%, and the mean mitotic index in hematoxylin-eosin-stained preparations was 0.65%. There was a correlation between the cytoplasmic p105 index and mitotic index in hematoxylin-eosinstained preparations (y = 0.32x-0.003, r = .63). There was no significant relationship between the cytoplasmic p105 index or mitotic index in hematoxylin-eosin-stained preparations and prognosis. These results indicate that the cytoplasmic p105 index is not a predictive indicator for prognosis in patients with cervical squamous cell carcinoma, although this index is a more accurate mitotic index than the mitotic index itself in hematoxylin-eosin-stained preparations.

Adult↗
PubMed1994

Renoprotective effect of nisoldipine in rats with severe hypertension.

OBJECTIVE: To compare the protective effect against cardiac and renal damage of a beta-blocker, an angiotensin converting enzyme inhibitor and a calcium antagonist in severely hypertensive rats. METHODS: Six-week-old male spontaneously hypertensive rats (n = 24) were given 100 mg/kg deoxycorticosterone and a 4% NaCl diet. They were then treated orally with vehicle, atenolol (70 mg/kg), enalapril (5 mg/kg) or nisoldipine (7 mg/kg) for 8 weeks. RESULTS: Control (vehicle-treated) rats developed marked hypertension after 8 weeks. The antihypertensive effect of the three drugs was similar, as were the reductions achieved in cardiac weight and aortic thickness. However, histological examination revealed that nisoldipine was significantly more effective than the other drugs in reducing renal arteriolar lesions and renal glomerular sclerosis. Only nisoldipine significantly improved plasma creatinine and the glomerular filtration rate. CONCLUSION: These findings suggest that calcium antagonists have a renoprotective effect in severely hypertensive rats, which may derive from the inhibition of arteriolar damage and glomerular sclerosis.

Animals↗
PubMed1994

Intracellular calcium signals are enhanced for days after Pavlovian conditioning.

Previous observations have implicated GABA as a neurotransmitter released by the vestibular sensory neurons ("hair cells") of the snail Hermissenda onto visual sensory neurons, the type B cells, whose cell bodies are the sites of biophysical and biochemical changes during and following Pavlovian conditioning. Still other observations demonstrated that light-GABA pairings that simulate stimuli presented during Pavlovian conditioning cause prolonged elevation of intracellular Ca2+ and transformation of GABA-induced synaptic inhibition into excitation. Intracellular Ca2+ signals in response to GABA perfused onto the postsynaptic type B terminal branches are shown here to be prolonged on days after conditioning, but not after control paradigms. These and past results demonstrate two separate sites, i.e., the cell body and the terminal branches, for learning-induced changes after Pavlovian conditioning.

Animals↗
PubMed1994

Primary gastric T-cell lymphoma. Morphological and immunohistochemical studies of two cases.

Primary T-cell lymphoma of the stomach is very rare. We report two cases of primary gastric T-cell lymphoma, one of which had a morphological appearance and a phenotype that were similar to those of node-based peripheral T-cell lymphoma. The other case was related to human T-cell lymphotropic virus type I and displayed a feature of lymphoma cell pleomorphism. The lymphoma cells were both positive for Ki-1/CD30.

Blotting, Southern↗
PubMed1994

A case with primary gastric lymphoma producing IgM and IgG immunoglobulins.

We describe a primary gastric lymphoma with IgM kappa and IgG kappa types of immunoglobulin in the neoplastic cells. The neoplastic cells containing IgM were morphologically different from those containing IgG. The IgG-bearing cells had globular cytoplasmic inclusions, but IgM-bearing cells did not. The neoplastic cells had two Ig heavy-chain gene rearrangements, with a germline band and a single kappa light-chain gene rearrangement. Immunoglobulin expression with light-chain restriction of the neoplastic cells and single light-chain gene rearrangement indicated that the morphologically different neoplastic cells were derived from a common progenitor. The expression of IgM and IgG and two rearrangement bands of immunoglobulin heavy-chain gene suggested that class switching might have occurred in the lymphoma cells.

Aged↗
PubMed1993

Simple and accurate high-performance liquid chromatographic method for the measurement of three antiepileptics in therapeutic drug monitoring.

A high-performance liquid chromatographic method for simultaneous determination of three antiepileptics, phenytoin, phenobarbital, and carbamazepine, in serum for therapeutic drug monitoring is described. The drugs were extracted and injected onto a silica-gel column using a syringe-type minicolumn, Extrashot-Silica, packed with diatomaceous earth granules. We used dichloromethane for extraction-injection and n-hexane containing 0.2% acetic acid, 2% ethanol, and 15% dichloromethane for the mobile phase of a silica-gel HPLC. The eluent was monitored with a UV detector set at 240 nm. Linear relationships between the amount of drug and peak height were confirmed at 1-20 micrograms/ml in serum for carbamazepine and 5-40 micrograms/ml in serum for phenytoin and phenobarbital. When a 5-microliters aliquot of serum was subjected to this method, the observed detection limits of the drugs were far less than therapeutic concentrations. Thus, our method was simple and accurate enough to be used in routine therapeutic drug monitoring and basic pharmacokinetic studies.

Anticonvulsants↗
PubMed1993

Local control prediction by histologic grading or radiation effects with drill biopsy specimens for uterine cervical cancer.

PURPOSE: Local control predictability by histologic grading for radiation effects was analyzed on 224 patients with cervical squamous cell carcinomas obtaining complete regression. METHODS AND MATERIALS: The cervical specimens after radiation therapy were obtained by drill biopsy technic. Radiation effect was assessed with Shimosato's histologic classification for radiation effect. RESULTS: The cancer tissues were altered by radiation to various degree from destruction of cancer nests with numerous viable cancer cells indicating grade 2a to scar tissues without viable or non-viable cancer cells indicating grade 4 at the end of treatment. Forty five percent of the patients had viable cancer cells remaining on the specimens at that time. The numbers of the grades 2a, 2b, 3, and 4 in biopsy specimens were 36, 65, 39, and 84, respectively. The local control rates and 5-year survival rates were 53% and 28% for grades 2a, 75% and 51% for grade 2b, 95% and 74% for grade 3, and 92% and 76% for grade 4, respectively. The histologic grading was significantly associated with the local control and 5-year survival. Of 41 patients having remaining viable cancer cells, residual tumors disappeared in 33 patients (80%) and 8 (20%) still persisted to show grades 2a-b at 1 to 2 months after radiotherapy. Of the 8, all four patients without any salvage treatment, died of local recurrence. CONCLUSION: These results suggested that the remaining viable cancer cells in the specimens at 1 to 2 months after radiation therapy were highly associated with recurrence and that the histologic grading system was an indicator predictive for prognosis.

Biopsy↗
PubMed1993

Transient increases of growth fraction during fractionated radiation therapy for cervical carcinoma. Ki-67 and PC10 immunostaining.

BACKGROUND: The Ki-67 and PC10 indexes are consistent with the growth and S-phase fractions, respectively. METHODS: Eighty-three biopsy specimens from 18 patients with cervical squamous cell carcinoma were examined before and during fractionated radiation therapy (RT), using an immunohistochemical method. RESULTS: The 18 patients were divided into two groups according to the Ki-67 index before RT; those with values of less than 42% (Group A; n = 11) and those with values of 42% or more (Group B; n = 7). The Ki-67 index in Group A increased approximately twofold at radiation doses of 5.4-9 Gy compared with values before RT. The Ki-67 index in Group B, which increased slightly at doses of 5.4-9 Gy, decreased by approximately one-fifth at a dose of 27 Gy, compared with the value before RT. The PC10 indexes in both groups showed little change to doses of 5.4-9 Gy. The mitotic indexes were less than 1% before RT and decreased to a minimum with doses of 18-27 Gy. There was no correlation between the Ki-67 and PC10 indexes before or during RT. CONCLUSION: In cancer tissues with a low growth fraction before RT, radiation doses of 5.4-9 Gy produced increases in the numbers of cycling cancer cells in the G1 or G2 phases. This transient increase possibly was attributable to the combined effects of the recruitment phenomenon and G1 or G2 block.

Adult↗
PubMed1993

Differential values of Ki-67 index and mitotic index of proliferating cell population. An assessment of cell cycle and prognosis in radiation therapy for cervical cancer.

BACKGROUND: Little is known about correlations between the growth fraction determined immunohistochemically with Ki-67 antibody and radiation response or prognosis after radiation therapy. METHODS: The prognostic value of the growth fraction determined by Ki-67 index and the mitotic index of proliferating cell population (pMI) were assessed in 45 cervical cancers treated with radiation therapy. The specimens from the cervix before radiation therapy were immunohistochemically stained with anti-Ki-67 antibody. RESULTS: The mean Ki-67 index and pMI for all patients were 36.0% and 2.74%, respectively. The patients with a Ki-67 index of 33% or greater showed significantly better histologic response to radiation at 30 Gy than those with less than 33%. The mean Ki-67 index for patients with good prognosis was significantly higher than for patients with tumor recurrence or metastasis later. Further, the mean values of pMI for patients with good prognosis were significantly lower than for patients with recurrence or metastasis. The 3-year survival rate for higher Ki-67 index (> or = 33%) was significantly better than lower Ki-67 index (less than 33%) (90.9% versus 34.8%; P < 0.001). However, the 3-year survival rate for higher pMI (> or = 3.5%) was significantly poorer than lower pMI (less than 3.5%) (8.3% versus 81.8%; P < 0.001). CONCLUSIONS: These results suggested that tumors with a high growth fraction showed a good prognosis with radiation therapy. In addition, the inverse prognostic correlation between the Ki-67 index and pMI suggested that both indices have independent values on radiation response and prognosis after radiation therapy.

Biomarkers, Tumor↗
PubMed1993

Potassium channel dysfunction in fibroblasts identifies patients with Alzheimer disease.

Since memory loss is characteristic of Alzheimer disease (AD), and since K+ channels change during acquisition of memory in both molluscs and mammals, we investigated K+ channel function as a possible site of AD pathology and, therefore, as a possible diagnostic index as well. A 113-pS tetraethylammonium (TEA)-sensitive K+ channel was consistently absent from AD fibroblasts, while it was often present in young and aged control fibroblasts. A second (166-pS) K+ channel was present in all three groups. Elevated external potassium raised intracellular Ca2+ in all cases. TEA depolarized and caused intracellular Ca2+ elevation in young and aged control fibroblasts but not AD fibroblasts. The invariable absence of a 113-pS TEA-sensitive K+ channel and TEA-induced Ca2+ signal indicate K+ channel dysfunction in AD fibroblasts. These results suggest the possibility of a laboratory method that would diagnostically distinguish AD patients, with or without a family history of AD, from normal age-matched controls and also from patients with non-AD neurological and psychiatric disorders.

Adult↗
PubMed1993

p53CM1 expression is not associated with prognosis in uterine cervical carcinoma.

BACKGROUND AND METHODS: Specimens obtained from 192 patients with Stage III squamous cell carcinoma of the cervix treated by radiation therapy alone were investigated with an immunohistochemical method for the expression of p53CM1, a monoclonal antibody that recognizes wild and mutant type p53 gene products in histologic materials fixed and processed conventionally. RESULTS: Cancer cells that had positive results for p53CM1 showed a nuclear staining pattern. Of the 192 patients, 99 had tumors that had negative findings (-) for p53CM1, 44 had tumors that were weakly reactive or ambiguous (+/-), 36 had tumors with positive results (+), and 13 had strongly reactive tumors (++). There was no significant correlation between survival of patients and p53CM1 (-) or (+/-) expression or p53CM1 (+) or (++) expression (chi-square test and Kaplan-Meier method, P = 0.466). CONCLUSIONS: The p53CM1 expression in cancer cells is not a predictive factor for the prognosis of patients with cervical carcinoma.

Adult↗
PubMed1993

Aqueductal stenosis due to mesencephalic venous malformation: case report.

The authors report the case of a 43-year-old woman with a venous malformation of the mesencephalon occluding the sylvian aqueduct. Neuroradiological investigations suggested aqueductal stenosis, while the presence of a venous malformation was diagnosed by both magnetic resonance imaging and an angiogram, and was visualized using a neuroendoscope. This is the first reported instance of a venous malformation being observed in situ and the subependymal course taken.

Adult↗
PubMed1993

An observation of the third ventricle under flexible fiberoptic ventriculoscope: normal structure.

The third ventricle, which is deeply seated in the center of the brain, is one of the most inaccessible regions from which to obtain information before surgery. A new flexible fiberoptic endoscope for examination of the ventricles is presented herein. The main advantages of this new device over existing fiberoptic instruments are the extended flexibility of the tip and its small diameter. Using this endoscope, one can observe the third ventricle in situ in patients with hydrocephalus associated with various lesions. The neural and vascular structures in the inner wall of the third ventricle are also illustrated.

Cerebral Ventricles↗