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Biomedical subjects

S Ohta

Publications and source records attributed to S Ohta.

At least 289 records · Page 16Linked to original sources
PubMed1998

Usefulness of heavily T2-weighted magnetic resonance imaging in patients with cerebellopontine angle tumors.

OBJECTIVE: Heavily T2-weighted magnetic resonance imaging (MRI) has been reported to be useful for the diagnosis of lesions of the inner ear or its central connections. We evaluated the usefulness of heavily T2-weighted MRI in 18 patients with cerebellopontine angle tumors. METHODS: The lesions were acoustic neuromas in 14 patients and meningiomas in 4 patients. The findings of heavily T2-weighted MRI were compared with those of three-dimensional T1-weighted gradient field echo MRI. RESULTS: An accurate description of the situation of the tumor in the internal auditory canal (IAC) was possible, because the inner ear was clearly shown on the heavily T2-weighted magnetic resonance images. We could therefore detect the acoustic neuromas located at the fundus of the IAC and the meningiomas growing into the IAC. The residual tumor in the IAC can be shown postoperatively. It was difficult to demonstrate these findings using three-dimensional T1-weighted gradient field echo MRI because of the poor presentation of the petrous bone structures. The lower cranial nerves and the VIIth and VIIIth cranial nerves were more clearly demonstrated by heavily T2-weighted MRI than by three-dimensional T1-weighted gradient field echo MRI. Using heavily T2-weighted MRI, the VIIth and VIIIth cranial nerves of the lesion side were demonstrated in half of the patients with acoustic neuromas smaller than 2.5 cm. CONCLUSION: We conclude that heavily T2-weighted MRI is useful to detect the relationship among the tumor, the IAC, the inner ear, and the surrounding cranial nerves.

Adult↗
PubMed1998

Angioplasty after intra-arterial thrombolysis for acute occlusion of intracranial arteries.

BACKGROUND AND PURPOSE: The purpose of this study was to report our experience with percutaneous transluminal angioplasty (PTA) of intracranial arteries in acute stroke patients who were resistant to intra-arterial thrombolysis alone. METHODS: PTA was performed within 6 hours from symptom onset in 13 acute stroke patients in whom no hypodensity areas were observed on initial CT. PTA was classified into 3 categories: immediate (3 patients), delayed (3 patients), and rescue (7 patients) angioplasty. Treatment results in the PTA group for 9 cases of middle cerebral artery (MCA) occlusion were compared with those in the thrombolysis alone group for 12 cases of thrombotic MCA occlusion. RESULTS: Technical success rates for immediate, delayed, and rescue angioplasty were 100%, 100%, and 71%, respectively, and that of angioplasty for the MCA was 100%. Ten patients (77%) showed improvement in the National Institutes of Health (NIH) stroke score after treatment. Improvement in NIH stroke scores in the PTA group for MCA occlusion was greater than that in the thrombolysis alone group (P<0.01). Nine patients (69%) had an excellent, good, or fair outcome 3 months after treatment. In 9 patients who had follow-up angiography 1 month after treatment, no restenosis or reocclusion was demonstrated. There were no symptomatic complications during or after treatment. CONCLUSIONS: This limited study demonstrates the technical feasibility of angioplasty for intracranial arteries in acute ischemic stroke and suggests that angioplasty may be an effective option for improving the success rate of recanalization and preventing reocclusion of the MCA. The present results encourage us to perform further clinical trials in a larger number of patients to assess the efficacy of this procedure.

Aged↗
PubMed1998

Quinone-dependent tertiary amine N-oxide reduction in rat blood.

Rat blood exhibited a significant quinone-dependent N-oxide reductase activity towards imipramine N-oxide. The reduction mediated by the blood proceeded in the presence of both NAD(P)H and menadione under anaerobic conditions. When menadione was replaced with 1,4-naphthoquinone or 9,10-phenanthrenequinone, similar results were obtained. The reduction was also mediated by the combination of rat erythrocytes and plasma. The reducing activity was inhibited by dicumarol and carbon monoxide. When boiled plasma was combined with untreated erythrocytes, the N-oxide reducing activity was abolished. In contrast, when boiled erythrocytes were combined with untreated plasma, the activity was unchanged. These results suggest that the activity is caused by the heme of hemoglobin in erythrocytes and quinone reductase in plasma. In fact, erythrocytes and hemoglobin have the ability to reduce the N-oxide when supplemented with DT-diaphorase purified from rat liver in the presence of both NAD(P)H and menadione. Hemoglobin also exhibits N-oxide reductase activity with reduced menadione (menadiol). Furthermore, hematin exhibits a significant reducing activity in the presence of menadiol. The reduction appears to proceed in two steps. The first step is enzymatic reduction of quinones to dihydroquinones by quinone reductase(s) with NADPH or NADH in plasma. The second step is nonenzymatic reduction of imipramine N-oxide to imipramine by the dihydroquinones, catalyzed by the heme group of hemoglobin in erythrocytes. Cyclobenzaprine N-oxide and brucine N-oxide are similarly transformed to the corresponding amines by the above reducing system in blood. These results suggest that blood plays an important role in the reduction of tertiary amine N-oxides to tertiary amines.

Animals↗
PubMed1998

Successful treatment of infertility due to anejaculation with in vitro fertilization and embryo transfer: a report of two cases.

We investigated the efficacy of assisted ejaculation in combination with in vitro fertilization and embryo transfer (IVF-ET) in two couples with infertility due to anejaculation. Case 1 was in an anejaculatory condition associated with a spinal cord-injury. We performed intrauterine insemination (IUI) three times using motile sperm obtained by intrathecal injection of neostigmine, but no pregnancy followed. The couple then entered IVF-ET. The semen volume obtained by assisted ejaculation was 4.5 ml. The sperm count was 33 x 10(6)/ml with 33% motility. At 35 weeks of gestation she delivered three healthy babies by cesarean section. Case 2 was in an unexplained retrograde ejaculatory condition. We performed IUI eight times before changing to IVF-ET. We then used sperm obtained from urine or sperm recovered from the bladder after administration of human tubal fluid, but no pregnancy followed. At the fifth IVF-ET attempt, using sperm obtained from urine, we succeeded. We prepared the sperm by the Percoll gradient method. The sperm count was 36 x 10(6)/ml with 64% motility. At 39 weeks of gestation she delivered a healthy baby. Deficient seminal quality contributes to the decreased fertility potential in patients with anejaculation. With the use of IVF-ET methods, pregnancies can be achieved in these couples.

Adult↗
PubMed1998

Hepatic veno-occlusive disease in a case of polymyositis associated with thrombotic thrombocytopenic purpura/hemolytic uremic syndrome.

A 50-year-old woman was treated with prednisolone for polymyositis. During the therapy, thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS) occurred. Neither plasma infusion nor plasma exchange could relieve the clinical manifestations of TTP/HUS. Moreover, massive ascites appeared and worsened her condition. She died approximately one year after the diagnosis of polymyositis. The autopsy revealed centri-lobular hepatic necrosis and nonthrombotic obliteration of hepatic small veins. The diagnosis of hepatic veno-occlusive disease (VOD) was made. It was suspected that common factors other than cytoreductive therapy had damaged the endothelium and caused TTP/HUS and VOD in a case of polymyositis.

Anti-Inflammatory Agents↗
PubMed1998

Surgical indications for and limitations of staged transsphenoidal surgery for large pituitary tumors.

Surgical indications and limitations of transsphenoidal surgery and intentionally staged transsphenoidal surgery for large pituitary tumors were investigated by retrospective analysis of the surgical and neuroradiological findings of 22 patients with large tumor and suprasellar extension. Twelve patients underwent intentionally staged transsphenoidal surgery, and 10 underwent combined transsphenoidal and transcranial surgeries. Successful removal by intentionally staged surgery required descent of the suprasellar part following the first transsphenoidal surgery. Analysis showed that a smooth suprasellar extension and/or soft tumor are indications for intentionally staged transsphenoidal surgery even in patients with small sella. However, lobulated suprasellar extension, fibrous and firm tumor without descent, and small sella with normal pituitary gland located at the bottom of the sella are contraindications for staged transsphenoidal surgery. The first transsphenoidal surgery is always indicated to achieve histological confirmation and decompression of optic nerves. Transcranial surgery should be attempted instead of repeated transsphenoidal surgeries when the residual tumor does not descend following the first transsphenoidal surgery.

Adult↗
PubMed1998

Epidemiological study of sarin poisoning in Matsumoto City, Japan.

On the night of June 27, 1994, about 12 liters of sarin were released by terrorists in Matsumoto City, Japan. In order to investigate the epidemic, community-based questionnaire surveys were conducted. The subjects were all inhabitants (2052 people) living and staying in an area of 1050 meters from north to south and 850 meters from east to west including the sarin release site. Participants included 1743 people who answered the questionnaire at the first survey; those with symptoms were contacted for follow-up at four months and one year after the episode. The number of sarin victims were 471 persons. Muscarinic signs were common to all victims; nicotinic signs were only seen in severely affected victims. The geographical distribution of sarin victims was closely related to the direction of the wind. Three weeks after the intoxication, 129 victims still had some symptoms such as dysesthesia of the extremities. At that time, many victims had begun to experience asthenopia, which was even more frequent at four months. Although victims who felt sarin-related symptoms had decreased by a year, some still had symptoms such as asthenopia. Sarin released in a suburban area affected approximately 500 inhabitants living nearby; some still had symptoms a year after the intoxication.

Adolescent↗
PubMed1998

Expression of matrix metalloproteinase 7 (matrilysin) in human osteoarthritic cartilage.

Matrix metalloproteinases (MMP) consisting of at least 16 different molecules are thought to be involved in the degradation of extracellular matrix (ECM) macromolecules under various pathologic conditions. Among them, MMP-7 (matrilysin) is unique in that it has high specific activity against various ECM components such as cartilage proteoglycan. In the present study, we examined the expression and tissue localization of MMP-7 in articular cartilages of human osteoarthritis (OA). Immunohistochemistry using a monoclonal antibody specific to MMP-7 demonstrated that the proteinase is localized to the OA chondrocytes mainly in the superficial and transitional zones in 92% of the OA cases examined (36 of 39 cases). On average, approximately 30% of the total chondrocytes (29.1%+/-30.2%) were immunostained in the positive OA cartilage samples. In contrast, MMP-7 staining was found in 8% of the normal cartilage cases (1 of 12 cases), and only a few chondrocytes (0.15%+/-0.67%) in the superficial zone were immunostained. There was a linear correlation between degree (%) of the immunostained chondrocytes and Mankin scores (rho [rho] = 0.84). Immunoblot analysis of the culture media from the cartilage explants demonstrated MMP-7 in 65% of the OA cases (15 of 23 cases) and 8% of the normal specimens (1 of 12 cases). Reverse transcription-PCR demonstrated the specific amplicon in 68% of the OA cartilage cases (17 of 25 cases), whereas only 18% of the control (2 of 11 cases) amplified the product. In situ hybridization revealed that the chondrocytes in OA cartilage express MMP-7 mRNA. MMP-7 gene expression in cultured OA chondrocytes was enhanced by the treatment with interleukin-1alpha and/or tumor necrosis factor-alpha. These data demonstrate for the first time that MMP-7 is overexpressed in human OA cartilage and suggest that cytokine-induced MMP-7 may play an important role in the degradation of ECM macromolecules in the OA cartilage.

Adult↗
PubMed1998

[Survival in patients with clear cell carcinoma of the ovary].

Thirty-one patients with clear cell ovarian carcinoma who underwent primary surgery and postoperative therapy were retrospectively evaluated. Eighteen patients (58%) had International Federation of Gynecology and Obstetrics (FIGO) stage I disease, 3 patients (9.7%) stage II disease, and 10 patients (32.3%) stage III and IV disease. Patients with stage III and IV disease demonstrated a significantly poor prognosis compared with patients who had stage I or II disease (p < 0.01). No patients with stage III and IV disease survived 5 years. p53 protein expression and proliferative activity (PA) were studied by immunohistochemical methods using p53 molecule and antibodies to PCNA (proliferative cell nuclear antigen). Intranuclear accumulations of p53 product were observed in 15 of 31 (48.4%). On the other hand, 15 of 31 (48.4%) patients stained positively for PCNA (> or = 60% of cancer cells stained positively). Positive p53 staining and highly PA were associated with poor survival. Two patients with stage I a relapsed were positive p53 and highly PA. Accordingly, consolidation chemotherapy is necessary for patients with stage I a who are positive p53 and highly PA. Platinum-based chemotherapy for patients who had minimal residual tumor was effective, but 5 patients who had > or = 2 cm tumor burden were not effective at all. The response rate for platinum-based chemotherapy was 20% (1/5) among p53 positive, in contrast to 66.7% (4/6) among p53 negative patients. So it seems that p53 positive patients are chemoresistant.

Adenocarcinoma, Clear Cell↗
PubMed1998

[A case of primary lung cancer presenting as pneumothorax].

A 62-year-old man presented pneumothorax as a first manifestation of lung cancer was described. The patient complained right side chest pain and dry cough of 6 days duration. On the day of admission, a chest radiograph showed a large pneumothorax on the right. After 3 days of tube drainage, the lung was re-expanded and a chest radiograph showed a mass density above the right hilum. A chest CT revealed a cavitating tumor of the right upper lobe with a fistula to the pleural space. Right upper lobectomy was performed, and the histology was squamous cell carcinoma. The cause of pneumothorax was bronchopleural fistula secondary to rapid growth of the cancer. Pneumothorax due to primary lung cancer is rare and the prognosis is poor because the cancer was advanced stage or diagnosis of cancer was delayed in the literature review. Lung cancer should always be considered as a possible cause of pneumothorax, and it is important to diagnose lung cancer as soon as possible.

Carcinoma, Squamous Cell↗
PubMed1998

[An operative case of primitive neuroectodermal tumor in the posterior mediastinum].

A primitive neuroectodermal tumor (PNET) is very rare and the prognosis of this tumor is poor. A 32-year-old woman complaining of dysphagia and back pain was admitted to our hospital for the posterior mediastinal tumor. The tumor originated from the muscle layer of esophagus and en bloc resection of the tumor combined with the affected part of esophagus was performed. Histopathological diagnosis of the resected tumor was PNET. She received adjuvant chemotherapy. Eight months after the surgery, recurrent tumors in the right mediastinum and the retrooperitoneal space was resected completely. But after the second surgery, dissemination occurred recurrently. These recurrent tumors revealed high sensitivity for radio-therapy. However, she died of rapid recurrence 22 months after the first surgery. In Japan, our case is the second case of PNET in the posterior mediastinum and the first case of PNET arising from the muscle layer of esophagus.

Adult↗
PubMed1998

[Two elderly patients with thoracic herpetic pain and post herpetic neuralgia treated with continuous thoracic sympathetic ganglion block through a placed catheter].

Epidural block is very useful in the treatment of herpetic pain and post herpetic neuralgia. However, in the elderly patients with cardiac disease or diabetes mellitus, severe cardiovascular changes may occur by epidural block. Epidural block caused severe hypotension in two elderly patients with herpetic pain and post herpetic neuralgia who had diabetes mellitus or hypertension. Continuous thoracic sympathetic ganglion block with local anesthetics through a placed catheter reduced their pain and caused almost no changes in cardiovascular system.

Aged↗
PubMed1998

[The relationship between the pathways of the lymphatic drainage into the mediastinal nodes and the survival rate for N2 lung cancers underwent curative resection].

The pathways of the metastases to the mediastinal nodes were determined in each case of 68 N2 lung cancer patients undergoing mediastinal lymph node dissection. The relationship between the pathways of the metastases and the survival rate was examined in the 57 N2 lung cancer patients undergoing curative resection. The results were as follows: (1) The direct metastatic passage to the mediastinal nodes was observed in 32.1% in the right upper lobe. The survival rate of this group was 55.4% (4-year survival rate), and that of cases metastasized to the intrapulmonary and/or hilar nodes as well as mediastinal nodes was 42.4% (3-year survival rate). (2) The dominant lymphatic drainage from the middle lobe and the lower lobes flowed into the subcarinal nodes through the hilar nodes. 75% had involvement of the subcarinal nodes, and 33.3% had involvement of the upper mediastinal nodes. 5-year survival rate of the cases without the upper mediastinal nodes metastases was 59.0%, and that of cases metastasized to the upper mediastinal nodes was 26.7% (3-year survival rate). (3) The dominant lymphatic drainage from the left upper lobe flowed into the subaortic or paraaortic nodes. 5-year survival rate in the left upper lobe was 50.0%. It suggested that the cases metastasized to the mediastinal nodes via the direct passage in the right upper lobe, the cases in the left upper lobe, and the cases metastasized to the subcarinal nodes without the upper mediastinal nodes metastases in the middle lobe and the lower lobes had better prognosis.

Humans↗
PubMed1998

[A case of pulmonary arteriovenous fistula beneath the surface of the lung].

A 19-year-old woman complaining of exertional dyspnea was admitted to our hospital with an abnormal shadow on the left side of the chest. Laboratory examination revealed polycythemia and hypoxemia. Pulmonary angiogram demonstrated a pulmonary arteriovenous fistula beneath the surface of the left S10. Partial resection of the left S10 was performed. The wall of the arteriovenous fistula was flimsy and seemed to rupture easily. The sister of this patient also had a peripheral pulmonary arteriovenous fistula and suffered from repeating epistaxis. Rendu-Osler-Weber disease was diagnosed in both, and the sister underwent partial resection of the right S7, which contained the fistula. Their postoperative courses were uneventful. Hemothorax and hemoptysis are lethal complications of arteriovenous fistulae. In order to avoid the rupture of fistulae, surgical resection is the most reliable treatment. Pulmonary arteriovenous fistulae beneath the surface of the lung should be resected.

Adolescent↗