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Biomedical subjects

M Tanabe

Publications and source records attributed to M Tanabe.

At least 37 records · Page 2Linked to original sources
PubMed1996

Reperfusion causes significant activation of heat shock transcription factor 1 in ischemic rat heart.

BACKGROUND: The myocardial protective role of heat shock protein (HSP) has been demonstrated, and there has been increasing interest in stress response in the heart. We examined the DNA-binding activity of heat shock transcription factor (HSF), by which the transcription of heat shock genes is mainly regulated, during heat shock or ischemia/reperfusion in isolated rat heart. METHODS AND RESULTS: Rat hearts were isolated and perfused with Krebs-Henseleit buffer by the Langendorff method. Whole-cell extracts were prepared for gel mobility shift assay using oligonucleotides containing the heat shock element, which is present upstream of all heat shock genes. Induction of mRNAs for HSP70, HSP90, and GRP78 (glucose-regulated protein) was examined by Northern blot analysis. Although the activation of HSF during global ischemia was weak and rapidly attenuated, postischemic reperfusion induced a significant activation of HSF. In addition, although HSP70 mRNA was hardly induced during ischemia, its burst induction was detected during postischemic reperfusion. Supershift assays using specific antisera for HSF1 and HSF2 revealed that ischemia/reperfusion as well as heat shock induced the activation of HSF1 in hearts. Although the expression of HSP70 mRNA during heat shock was more vigorous than the expression during ischemia/reperfusion, the induction of HSP90 mRNA in postischemic reperfusion was significantly greater than that in heat shock. CONCLUSIONS: Our findings demonstrated that reperfusion causes a significant activation of HSF1 in ischemia-reperfused heart. The striking contrast between the induction of HSP70 mRNA and that of HSP90 mRNA suggests the presence of regulatory mechanisms other than HSF.

Animals↗
PubMed1996

Preferential enhancement of inhibitory synaptic transmission by CS-722 in the ventral horn neurons of neonatal rat spinal cord.

We studied the modulatory effect of (R)-4-chloro-2-(2-hydroxy-3-morpholinopropyl)-5-phenyl-4-isoxaz olin-3-one hydrochloride (CS-722), a centrally acting muscle relaxant, on synaptic transmission in the ventral horn neurons of neonatal rat lumbar spinal cord in slices using whole cell recording techniques. Pharmacologically isolated excitatory or inhibitory postsynaptic currents (EPSCs and IPSCs) were evoked by stimulating neighboring neurons. CS-722 preferentially enhanced IPSCs with little effects on EPSCs. Moreover, CS-722 reduced paired pulse facilitation of gamma-aminobutyric acid (GABA)-mediated IPSCs, suggesting its action on the presynaptic terminal. Preferential facilitatory effects on inhibitory synaptic transmission seem to be one of the mechanisms underlying muscle relaxation of this compound.

Animals↗
PubMed1996

Paired pulse facilitation of GABAergic IPSCs in ventral horn neurons in neonatal rat spinal cord.

Whole-cell patch-clamp recording of GABAergic inhibitory postsynaptic currents (IPSCs) were made in ventral horn neurons of neonatal rat lumbar spinal cord in slice. In contrast to the hippocampus where paired pulse depression is reported to be observed for GABAergic IPSCs, double pulse stimulation of GABAergic inputs resulted in enhancement in the amplitude of the second IPSC in the spinal ventral horn. The facilitation ratio was decreased during enhanced synaptic transmission by increasing Ca2+ concentration in the external recording solution. Baclofen and adenosine. which are reported to depress synaptic transmission by presynaptic mechanisms, depressed IPSCs and increased the facilitation ratio. A postsynaptic manipulation such as application of bicuculline or changing the driving force did not affect the facilitation ratio. These results suggest that paired pulse facilitation of GABAergic IPSCs observed in neonatal rat spinal ventral horn appears to be based upon a mechanism similar to that underlying frequency-dependent facilitation of excitatory synaptic transmission, and is sensitive to presynaptic changes in synaptic strength.

Adenosine↗
PubMed1996

Histopathologic analysis of bone marrow and bone metastasis in murine neuroblastoma.

To elucidate the development of bone metastasis in human neuroblastoma, bone marrow and bone metastases were analysed histologically in a hematogeneous metastasis model of murine neuroblastoma. The bone marrow metastasis occurred initially in the bone marrow sinusoid where tumor cells adhered and extravasated to bone marrow parenchyma, resulting in the formation of nodular lesions in the medullary cavity. The nodular lesions eventually progressed to diffuse lesions segmentally occupying the medullary cavity. During the establishment of the diffuse lesions, tumor cells invaded cancellous bone and/or bone cortex, resulting in bone metastasis. Such nodular or diffuse bone marrow metastatic lesions occurred sporadically in a variety of bones. To improve the results of treatment for neuroblastoma, the characteristics of the bone marrow and the bone metastases demonstrated in this study should be considered in the diagnosis and treatment of this disease.

Animals↗
PubMed1996

Accumulation of Tc-99m MIBI in breast lymphoma: comparison with Ga-67 citrate.

We report 2 cases of malignant lymphoma of the breast which were clearly shown on total body imaging as well as on SPECT with Ga-67 and Tc-99m MIBI. Tumor accumulation of Ga-67 was seen in all cases including a recurrent tumor. Ga-67 scintigraphy is useful for follow up in detecting relapse, as well as in predicting responses to therapy. Tc-99m MIBI was found to accumulate in the malignant lymphoma of the breast, and especially SPECT images of breast lesions provided better contrast than planar images, and Tc-99m MIBI SPECT could diagnose localization of the tumor because there was no uptake by the breast. But the Tc-99m MIBI accumulation of the tumor was lower than Ga-67.

Breast Neoplasms↗
PubMed1996

Renal impairment after surgical resection of neuroblastoma.

Postoperative renal impairment was observed in 6 of 58 patients with neuroblastoma treated between November 1982 and March 1994. To clarify the clinical characteristics of these patients (renal-impairment group), they were compared with 26 patients treated during the same period who did not have renal impairment (no-impairment group). The incidence of primary retroperitoneal tumor and invasion of the hilum renalis was clearly higher in the renal-impairment group than in the group with no impairment. However, no significant difference was observed with respect to age, tumor laterality, or stage of disease. The results of postoperative biochemical examinations showed that the serum concentrations of lactic dehydrogenase were significantly higher in the renal-impairment group. In the group with renal impairment, the mean maximal body temperatures on the first, second, and third postoperative days were 38.7 degrees C, 38.6 degrees C, and 38.1 degrees C, respectively. These were higher than those of the no-impairment group. For patients with these risk factors, intraoperative prophylactic measures and early postoperative renal blood flow evaluation (in anticipation of postoperative renal impairment) are considered necessary.

Adrenal Gland Neoplasms↗
PubMed1996

Regular and irregular dichotomies of bronchial branching in the human lung.

RATIONALE AND OBJECTIVES: Typical models of the human bronchial tree depict regular branching. However, some anatomic studies also have revealed irregular dichotomies in the human lung. We therefore studied the patterns of bronchial branching in the human lung. METHODS: We examined a normal right lung. Bronchial branchings were traced up to terminal bronchioles (TBs) in both regular and irregular dichotomies. RESULTS: In 256 TBs in peripheral regions, the number of branchings varied from 11 to 23; the largest number was found in the S10c of the basal segment, and the average was 15. In 354 TBs in hilar regions supplied by irregular dichotomies, the number of branchings ranged from 9 to 15, with the average being 10. In secondary pulmonary lobules, bronchioles supplying the secondary pulmonary lobules reached TBs in two or three divisions. CONCLUSION: Irregular dichotomies are too frequent to be neglected in the interpretation of radiologic and physiologic findings.

Aged↗
PubMed1996

Septal structure of incomplete interlobar fissures of the lung.

RATIONALE AND OBJECTIVES: Some septal structures have been observed in the areas of incomplete interlobar fissures (IIFs) in resected lungs. We describe the anatomy of IIFs with or without the presence of septal structures. METHODS: Twenty fused areas from 16 autopsy cases were examined histologically. Other septal structures outside the areas of IIFs also were examined. RESULTS: In 10 of the 20 fused areas, there was a mixture of septal structures with and without defects. In the remaining 10, there were no septal structures. The septal structures consisted of two inner layers from both lobes. Other septal structures examined were the same as ones observed in the IIFs. CONCLUSION: Linear shadows seen at interlobar fissures and on computed tomography scans do not necessarily depict the presence of complete interlobar fissures. The absence of linear shadows does not necessarily imply the absence of septal structures.

Bronchi↗
PubMed1996

Cerebral vasospastic vessels: histologic changes after percutaneous transluminal angioplasty.

PURPOSE: To investigate histologic changes before and after percutaneous transluminal angioplasty (PTA) in experimental cerebral vasospasm in comparison with normal vessels. MATERIALS AND METHODS: In seven monkeys, vasospasm was induced in the subarachnoid space. After 7 days, PTA was performed. Microscopic studies were performed in vasospastic vessels. In two animals, vasospasm was induced but angioplasty was not performed. The controls were two animals without vasospasm who underwent only contralateral angioplasty. RESULTS: Angiography after vasospasm revealed marked narrowing but dilatation after PTA, without changes in distal spastic vessels. Specimens after PTA showed platelets that covered denuded endothelium, stretching, and focal dehiscence of internal elastic lamina and altered myocytes in media. Myocytes were deformed and arranged irregularly. These changes were not uniform. CONCLUSION: The prolonged effect of PTA may be caused by mechanical damage of myocytes and the nonuniformity of histologic changes in vascular walls.

Angioplasty, Balloon↗
PubMed1996

The effect of atrial natriuretic peptide on pulmonary acid injury in a pig model.

The effect of exogenous atrial natriuretic peptide (ANP) on pulmonary injury induced by aspiration of hydrochloric acid (0.1 N HCl, 2.0 ml/kg) was examined in anesthetized pigs ventilated with 100% oxygen. Group-specific diuretic treatment was used 60 min after aspiration and followed for a further 120 min. No diuretics were used for Group 1, 0.1 microg/kg/min of ANP was infused intravenously for 60 min in Group 2, and 0.05 mg/kg of furosemide was injected (intravenous bolus) in Group 3. Total urine volume after diuretic treatment did not differ significantly between Groups 2 and 3. However, the increase in PaO2 (to 386.3 +/- 67.5 mm Hg) after infusion of ANP was significantly higher than the increase in PaO2 (to 275.9 +/- 63.3 mm Hg) after furosemide treatment, and in the no treatment control (to 171.1 +/- 31.5 mm Hg). Pulmonary hypertension induced by acid aspiration was significantly reduced (p < 0.01 versus Groups 1 and 3) during ANP infusion. ANP has a beneficial effect on acute lung injury, possibly through its diuretic and/or pulmonary vasodilating action.

Animals↗
PubMed1996

Brainstem schwannoma--case report.

A 68-year-old female presented with rare brainstem schwannoma manifesting as right hemiparesis, diplopia, and dysphagia. Neuroimaging revealed a lesion in the pons and cerebral peduncle, which was supposed to be a highly malignant glioma. The mass was approached via a single-flap orbitozygomatic craniotomy through an anteromedial pericavernous approach. Intraoperative frozen-section specimens indicated glioma, but the tumor was distinct from the surrounding parenchyma, and could be removed successfully. A tumor capsule was found and also removed. Postoperative histological, immunohistochemical, and ultrastructural examinations confirmed the diagnosis of benign schwannoma. Most schwannomas, even in the brainstem, are benign and complete removal may be curative.

Aged↗
PubMed1996

[Portal embolization using lipiodol-gelatin sponge].

Gelatin sponge moistened with lipiodol was prepared for use in portal embolization to improve percutaneous transhepatic portal embolization as preoperative management of patients undergoing extensive liver resection. For one sheet of gelatin sponge (20 x 60 x 7mm)0.5ml of lipiodol was used. Five sheets cut to 2mm square pieces and mixed with physiological saline solution were injected into the right portal vein. This embolic material proved safer and more reliable than gelatin sponge mixed with water-soluble contrast medium, because it provided sufficient opacification to grasp the extent of embolization and prevented back flow.

Embolization, Therapeutic↗
PubMed1996

[Comparative evaluation of 99mTc-MIBI (hexakis2-methoxy isobutyl isonitrile) and 201Tl-chloride in primary lung cancer].

We performed comparative study, using 99mTc-MIBI and 201Tl-chloride in patients with primary lung cancer. There were 42 patients with primary lung cancer. All patients underwent dual radionuclide imaging with 201Tl-chloride and 99mTc-MIBI. Regions of interest were placed over the tumor area (T) and contralateral normal lung area (N). A tumor to normal lung ratio (T/N ratio) and retention index were calculated by early and delayed ratios. In the SPECT images, the positive rate was 98% in both the early and delayed images for 201Tl-chloride and 95% in the early and 88% in the delayed images for 99mTc-MIBI. Both early and delayed T/N ratios of 201Tl-chloride were significantly higher than those of 99mTc-MIBI. The retention index of 201Tl-chloride was higher than that of 99mTc-MIBI. T/N ratio and retention index did not significantly correlated with reference to histological types. We conclude that 99mTc-MIBI SPECT can be helpful in localizing primary lung cancers. However, in our study the tumor accumulation of 99mTc-MIBI was significantly lower compared with 201Tl-chloride.

Adult↗
PubMed1996

[Radiologic-pathologic correlation between tumor edge and surrounding inherent structures in peripheral lung cancer].

PURPOSE: To evaluate the radiologic-pathologic relationship between the tumor edge of peripheral lung cancers and surrounding normal structures. MATERIALS AND METHODS: Tissue samples from 16 lung cancers with diameters less than 2 cm were examined: 7 adenocarcinomas, 5 squamous cell carcinomas, 2 small cell carcinomas, 1 large cell carcinoma, and 1 that had metastasized to the lung. Inflation-fixed lung specimens containing tumor tissue were sliced to a thickness of 2 mm: The tumor edge of each section was traced under a stereomicroscope and its relationship to marginal structure, including bronchi, pulmonary arteries, and pulmonary veins containing interlobular septa, was analyzed. The tumor edge and marginal structures were classified into four types: Type 1, clear margin formed by marginal structures; Type 2, tumor involving the marginal structures; Types 3 and 4, marginal structures penetrating the tumor with and without a notch, respectively. RESULTS: Type 1 was found in 23 of 47 pulmonary arteries (49%), 23 of 49 bronchi (47%), and 12 of 31 pulmonary veins or interlobular septa (39%). Type 2 was found in 11% (14/127), Type 3 in 15% (19/127) and Type 4 in 28% (36/127) of marginal structures. Type 1 was common in all histological types of carcinomas studied. CONCLUSION: In small peripheral lung cancers, the tumor edge sometimes has a clear margin formed by surrounding structures such as interlobular septa. This can make it difficult to differentiate benign from malignant lesions.

Adenocarcinoma↗
PubMed1996

[An epidemiological study of malformations in infants delivered from diabetic mothers].

The purpose of this study is to investigate the risks of delivery of malformed infants in diabetic mothers in comparison with those in non-diabetic mothers and to clarify risk factors for malformation due to maternal diabetes. The delivery records available at the Department of Obstetrics and Gynecology, Mie University School of Medicine between 1979 and 1992 showed 103 mothers with diabetes mellitus among 4,353 pregnancies. The incidence of malformation in infants born to diabetic mothers was 9.7%, and it was 2.5% overall. By logistic regression analysis of all mothers in this series, diabetes as well as maternal age, and fetal age were shown to be significant risk factors for malformation. A further logistic model for diabetic mothers revealed that a younger age of the mother at the time of labour, low fetal age, older age at onset of diabetes, previous history of pregnancies, and an Hemoglobin A1 (HbA1) level higher than 9% were independent risk factors, among which HbA1 (>9%) showed the highest odds ratio of 24. Careful management is therefore needed to reduce the risk of malformation in pregnancy of diabetic mothers.

Adult↗
PubMed1996

[Comparison between high-resolution computed tomography and 99mTc-technegas SPECT pulmonary emphysema].

Scintigraphy with 99mTc-technegas was recently introduced for clinical imaging of lung ventilation. This method has been found to be useful in emergencies, to be more suitable for single photon emission computed tomography (SPECT) than other agents used in ventilation scintigraphy, and could reveal abnormalities in ventilation more easily than high resolusion computed tomography (HRCT) in pulmonary emphysema. We compared 99mTc-technegas SPECT with HRCT in six regions: the right upper, middle, and lower lobes, the left upper lobe, the lingula, and the left lower lobe, in 15 patients with pulmonary emphysema. Patients with centrilobular emphysema tended to show stronger changes in upper lobes than in lower lobes on both 99mTc-technegas SPECT and HRCT. Some regions showed no change on HRCT but various changes on 99mTc-SPECT. Patients with panlobular emphysema showed severe changes on 99mTc-SPECT in lower lung fields in which well-demarcated areas of low attenuation were not seen on HRCT. We conclude that 99mTc-SPECT is useful for detecting early changes and panlobular changes in pulmonary emphysema.

Adult↗
PubMed1996

[Second phase 99mTc-HMDP accumulation using three phase bone scintigraphy in a case of primary breast cancer].

Accumulation of 99mTc-HMDP was recognized by three-phase bone scintigraphy in a case of primary breast cancer. A 67-year-old female was found to have a 14 x 13 mm mass in the upper lateral area of the left breast. At operation the histopathological finding was a proven solid-tubular carcinoma. On the first phase images, there was no abnormal accumulation in the tumor. On the second phase images, there was abnormal accumulation in the tumor, however, abnormal accumulation was observed followed by a decrease in accumulation. The third phase image showed no abnormal extra-skeletal accumulation. Color Doppler ultrasound sonography showed an abundance of color signals within the breast tumor. Increased 99mTc-HMDP accumulation in the second phase image might reflect tumor hypervascularization. It is concluded that three-phase bone scintigraphy using 99mTc-HMDP has the ability of positive description in primary breast cancer.

Adenocarcinoma↗