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Biomedical subjects

Y Nishimura

Publications and source records attributed to Y Nishimura.

At least 775 records · Page 43Linked to original sources
PubMed1991

Intraoperative radiation therapy for malignant glioma.

Intraoperative radiation therapy (IORT) was used as part of the initial therapy for malignant glioma in 32 of 73 patients with histologically verified anaplastic astrocytoma (grade III astrocytoma) and glioblastoma multiforme. The initial treatment for all cases was subtotal or total tumor resection combined with external irradiation and chemotherapy. IORT was performed 1 week after tumor resection, with doses of 10-50 Gy (mean 26.7 Gy) in one session. Fourteen of 32 cases had IORT two times because of tumor recurrence. The IORT patients had survival rates at 24 and 36 months after initial treatment of 57.1 and 33.5% (median survival 26.2 months). The other 41 patients had 23.6 and 13.1% survivals (median survival 20.7 months), which were significantly lower (p less than 0.01). Tumor recurrence within the original lesion site was suspected because of clinical condition, computed tomography, and magnetic resonance imaging studies in 65.6% of the IORT group (21 cases) 12 months after initial treatment. Twenty cases of death in the IORT group, including five autopsy cases, demonstrated regional tumor recurrence with a high incidence of intraventricular tumor invasion. The authors consider IORT is beneficial for selected malignant glioma patients, including tumor recurrence, because of prolonged survival.

Adolescent↗
PubMed1991

Neurophysiology of ischemic facial nerve paralysis in an animal model.

The establishment of an animal model for facial nerve paralysis is assuming increasing importance in clinical medicine and also in basic facial nerve research. We previously reported an animal model for ischemic facial nerve paralysis using selective vascular embolization through the internal maxillary and posterior auricular arteries in cats using Avitene which contains bovine microfibril collagen. In this paper, we determined the exact site of the lesion in established facial paralysis. A descending signal produced by direct stimulation to the contralateral motor cortex was able to elicit firing of the motor nucleus of the facial nerve, the extra-temporal portion of the peripheral nerve, and the orbicularis oris muscle. After achieving complete facial nerve paralysis, this descending signal was completely abolished within the temporal bone area, whereas peripheral facial nerve stimulation elicited a normal evoked electromyogram of the orbicularis oris muscle. The present results suggest that the site of the lesion of ischemic facial nerve paralysis produced by embolization in an animal model is within the temporal portion of the seventh nerve, and this animal model may lead to the advancement of future facial nerve research which cannot be conducted in humans.

Angiography↗
PubMed1991

Cytosolic calcium changes in cultured rat aortic smooth-muscle cells induced by oxyhemoglobin.

To clarify the mechanism of contractive effects in arteries caused by oxyhemoglobin, changes in the concentration of cytosolic calcium [( Ca++]i) before and after exposure to oxyhemoglobin were measured in vitro in cultured vascular smooth-muscle cells obtained from rat aorta. This was accomplished by preloading these cells with a fluorescent intracellular Ca++ probe fura-2/AM. Oxyhemoglobin induced a significant elevation of [Ca++]i in vascular smooth-muscle cells which was sustained for 10 minutes. This response was completely abolished by chelating extracellular calcium with ethyleneglycol-bis (beta-aminoethylether)-N,N'-tetra-acetic acid (EGTA). Oxyhemoglobin induced no accumulation of mass content of inositol 1,4,5-trisphosphate (IP3(1,4,5]. The oxyhemoglobin-induced elevation of [Ca++]i was not blocked by verapamil, a calcium antagonist. Serotonin induced a rapid, transient increase of [Ca++]i followed by a sustained elevation above baseline for 5 minutes. Additions of EGTA or verapamil had a small effect on the peak height of serotonin-induced [Ca++]i elevation, but the [Ca++]i level declined more quickly to the basal level in treated compared with control cells. These results indicate that oxyhemoglobin-induced [Ca++]i elevation is caused by the influx of extracellular calcium, which is independent of the verapamil-blocked voltage-gated calcium channel. The long-lasting high elevation of [Ca++]i caused by oxyhemoglobin suggests that oxyhemoglobin may contribute to the production of abnormal contractions and/or irreversible damage in vascular smooth-muscle cells.

Animals↗
PubMed1991

Induction of cytosolic free calcium elevation in rat vascular smooth-muscle cells by cerebrospinal fluid from patients after subarachnoid hemorrhage.

The purpose of this study was to determine the effects of cerebrospinal fluid (CSF) from patients with subarachnoid hemorrhage (SAH) on cytosolic free calcium in cultured rat vascular smooth-muscle cells using the fluorescent intracellular calcium indicator fura-2/AM. Samples of CSF were collected from 12 patients (seven with and five without vasospasm) on Days 2, 6, 11, and 16 after SAH. Control CSF samples were obtained from five patients 6 to 9 months after they had undergone successful aneurysm surgery following an SAH. All CSF samples in both the non-vasospasm and vasospasm groups, regardless of the day of sampling after the SAH, induced significantly higher transient intracellular calcium elevations when compared to levels induced by control CSF. Furthermore, the addition of 2 mM ethyleneglycol-bis (beta-aminoethylether)-N,N'-tetra-acetic acid (EGTA) caused a slight reduction in the peak height in the CSF-induced intracellular calcium rise which declined more rapidly to basal levels than those studied without EGTA. In the non-vasospasm group, the intracellular calcium concentration remained stable after SAH throughout the study period. In contrast, in the vasospasm group, this concentration was highest on Day 2 post-SAH, but sharply decreased on Day 6 and rose again on Day 11. This result correlated with the clinical signs of vasospasm in these patients. These findings indicated that the intracellular calcium elevations induced by CSF obtained after SAH were due to the combination of the influx of extracellular calcium and the mobilization of intracellular calcium from storage sites. The changes in intracellular calcium concentrations in vascular smooth-muscle cells induced by CSF obtained from patients on successive days following SAH suggest that the substances that induce this repeat calcium elevation on Day 11 post-SAH may be the key spasmogens for vasospasm after SAH.

Animals↗
PubMed1991

[Histological grading of alveolar type renal cell carcinoma based on architectural variation].

Ninety-two of a total 107 renal cell carcinomas excluding papillary, sarcomatoid and other uncommon histological types were classified into 3 groups based on architectural variations. Statistically analyses were carried out for prognostic significance. Histological criteria of 3 groups were defined as follows. Group I consists predominantly of tubular formations with characteristic cystic change. Group III shows solid proliferation without tubular formations, and Group II shows small alveolar or trabecular structures with inconspicuous tubular formations. According to the survival curves (Kaplan-Meier method), the prognosis of Group I was significantly better than II and III. Ten year survival rate of each group was 88 +/- 7.8% in Group I, 39 +/- 8.8% in Group II, and 0% in Group III. The distribution of T and V stages in the 3 groups were not significantly different. Nuclear grading of Group I and II was not so different, though high grade cases predominated in Group III. Therefore, the present grading of alveolar type renal cell carcinoma based on architectural atypia was considered to be a useful prognostic parameter.

Aged↗
PubMed1991

[Pharmacokinetic study of adriamycin in the emulsion mixed with lipiodol-difference resulting from composition and methods of preparation, and behavior after mesenteric arterial injection in rat].

We experimentally investigated the pharmacokinetics of adriamycin (ADM) in a similar of transcatheter arterial chemoembolization therapy (TAE) of hepatocellular carcinoma using emulsion of lipiodol (Lp) mixed with ADM followed by gelatin sponge, and the difference resulting from composition and method of preparation of the emulsion as well as behavior after mesenteric arterial injection in rat. In in vitro study, the emulsion with iopamidol (iopamiron 300 : IP) was more stable than with amidotrizoic acid (60% Urografin : UG). The highest stability was found in the mixing ratio of Lp. IP and distilled water at 1 : 0.42 : 0.08. Frequent pumping also made the emulsion more stable. But in optimally composed emulsion, pumping 20 or 50 times made no difference in the stability during 30 min. which may be longer than the time from preparation to injection time of the emulsion in clinical application. After injection of the emulsion into the mesenteric artery which may simulate injection into the hepatic artery in hepatocellular carcinoma, the arterial blood flow was suspended. In the peripheral arteries the emulsion separated into two phases of Lp and ADM solution, forming striped pattern, and Lp embolization of the peripheral artery persisted for over 45 min. while ADM extravasated. These findings suggest that after Lp-TAE, Lp maintains an embolizing effect while ADM penetrates into the surrounding tumor tissue, and that this is an underlying mechanism for the anti-cancer effect of Lp-TAE.

Animals↗
PubMed1991

[Visual impairment complicated with meningioma].

Among 106 patients of meningioma surgically experienced the past 10 years between 1981 and 1990, twelve of meningioma with progressive visual impairment were analyzed in relation to postoperative visual outcome. There were four males and eight females, and the age ranged from 33 to 61 years with the average 48 years. The distribution of tumor location was 6 cases in tuberculum sellae, 3 cases in the inner side of sphenoid ridge, and 3 cases in olfactory groove. The size of tumor in each case was 2 to 7 cm in diameter, and in 8 cases more than 3 cm. The duration of visual disturbance was between 3 months and 10 years with the average 3 years. For all cases, surgical removal of the tumor was performed totally by pterional and bifrontal approach. Consequently, 58.3% of 7 cases had improved vision postoperatively, 16.7% of 2 cases remained unchanged, and 25.0% of 3 cases were worse, including one case of malignant meningioma, Visual outcome was mainly affected by a duration of symptoms, a tumor size, a preoperative visual impairment, and in special, a situation of optic nerve where compression of tumor itself and adherence to the surrounding tissues took place. On operation, great care should be paid for a case of long-standing, severe visual disturbance as demonstrating hemianopsia with visual narrowing less than 50 degree by perimetry, and also for preservation of the feeding arteries of optic nerves.

Adult↗
PubMed1991

[Seropositivity of anti-HTLV-II antibodies in patients with HTLV-I-associated myelopathy and adult T-cell leukemia].

Dr Kira et al. (Lancet 1991, 338: 64-65) stress the high incidence of the co-infection with HTLV-I and HTLV-II in the HTLV-I associated myelopathy or tropical spastic paraparesis (HAM/TSP) detected by a polymerase chain reaction (PCR). They showed that 67% of HAM/TSP patients and 6% of healthy carriers had the co-infection. They suggested the co-infection might be important for the development of the myelopathy. Recently, we have analyzed the seropositivity of antibodies to HTLV-I and II in Adult T-cell Leukemia (ATL), HAM/TSP and carriers in Japan using SELECT-HTLV (IAF Biochem International Inc., Montreal, Canada). This system was a solid phase enzyme immunoassay utilizing synthetic peptides to differentiate between antibodies to type I and II. We examined 101 samples (31 ATL patients, 20 HAM/TSP and 50 carriers) which were all positive with the particle agglutination (PA, Fujirebio, Tokyo) and ELISA (Eisai, Tokyo). All samples were negative with HTLV-II and positive with HTLV-I. The results of our serological survey suggested that HTLV-II did not associate with the etiology of ATL and HAM/TSP in Japan.

HTLV-II Antibodies↗
PubMed1991

NMR spectroscopic study of single-stranded DNA fragments of d(CGGCGAAAGCCG) and d(CGGCAAAAGCCG).

We have investigated the structures of two kinds of single-stranded DNA fragments, d(CGGCGAAAGCCG) and d(CGGCAAAAGCCG), by use of NMR spectroscopy. It was found that the former takes a hair-pin like structure stabilized by hydrogen bonding of G/C base pairs in the stem region, while the latter takes a rather extended helical structure. The stable conformation of the former DNA is considered to originate from the stability of the sequence-specific conformation of the loop region rather than the stem region.

Base Sequence↗
PubMed1991

[Simultaneous detection of antibodies for 3 different retroviruses using retrovirus EIA (triple antigen kit)].

We evaluated Retrovirus EIA kit (Roche Co.), in which virus components of three different viruses, HIV-1, HIV-2, and HTLV-I were used antigens. All the specimens from the patients with ATL, HAM, HTLV-I carrier, AIDS and AC, and from HIV-2 infected individuals were found to be positive. Four out of 40 specimens from hemophiliacs not infected with HIV-1 were found out to be positive. These specimens were confirmed to contain antibody against HTLV-I. Pseudo-negative or -positive reactions were not found in this study. Therefore, Retrovirus EIA kit should be evaluated more extensively, for the possible applications for screening of blood donors, and for selecting the sources of blood products as well as for clinical diagnoses.

Acquired Immunodeficiency Syndrome↗
PubMed1991

[Pulmonary embolism complicated with stroke: analysis of 5 cases].

Though pulmonary embolism (PE) has been thought to be rare, the incidence seems to be increasing recently. During the past 10 years the authors have encountered 5 cases of PE among stroke patients. There were 2 males and 3 females, aged 51 to 71 years (mean age; 63 years). The mean time between admission and onset of PE was 23 days. As to the primary disease to be treated, 5 patients had subarachnoid hemorrhage and one had intracerebral hemorrhage. Generally, PE tends to be overlooked or misdiagnosed because of the fact that stroke patients are often in a state of unconsciousness. In our series, only one patient complained of dyspnea and the other 4 patients due to unexplained sudden tachycardia, tachypnea and hypoxemia were suspected to have PE. Deep venous thrombosis known as the risk factor leading to PE was presented in 3 patients. Especially in one patient, femoral venous catheterization was considered as a risk factor possibly leading to deep venous thrombosis. Regarding the diagnosis of PE, the roles of electrocardiogram and of chest x-ray film were small. In 3 patients, the elevation of the diaphragm was the only abnormal finding on chest X-ray. On the other hand, the lung scintigram with 99mTc-MAA was a useful method for definitive diagnosis of PE. In 3 patients, filling defects were demonstrated on the lung perfusion scintigrams. Consequently, we emphasize that PE must be kept in mind when tachycardia, tachypnea and hypoxemia appear suddenly. Prompt diagnosis and treatment are required.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

[The effect of aging on respiratory muscle function].

To elucidate the effect of aging on respiratory muscle function, the authors performed respiratory muscle function tests in 116 normal subjects. Respiratory muscle function was evaluated with maximal expiratory mouth pressure at the TLC level (PEmax) and maximal inspiratory mouth pressure at the RV level (PImax). PEmax and PImax in both sexes showed significant correlations with age. PEmax in males was significantly higher than that in females (123.6 +/- 29.7 cmH2O and 79.0 +/- 21.1 cmH2O, p less than 0.01, respectively). PImax in males was also significantly higher than that in females (98.4 +/- 26.0 cmH2O and 71.9 +/- 26.4 cmH2O, p less than 0.01, respectively). PEmax correlated significantly with TLC, and PImax showed a significant inverse correlation with RV/TLC. Furthermore, there was a significant inverse correlation between RV/TLC and age. Our data suggest that inspiratory muscle weakness in aging may be responsible for the increase in RV/TLC.

Adult↗
PubMed1991

[Estimation of atherosclerotic lesions in the thoracic aorta by transesophageal echocardiography].

The thoracic aorta is one of the portions frequently involved with atherosclerotic lesions. We estimated atherosclerotic lesions in the thoracic aorta in consecutive 137 patients (59 +/- 10 years old) using transesophageal echocardiography. The study population consisted of 60 with coronary artery disease (CAD), 36 with hypertension (HT), 28 with hypercholesterolemia (HC, total cholesterol greater than or equal to 230 mg/dl), eight with dissecting aneurysm, nine with true aneurysm and two with aortitis syndrome. We used a single transverse scan-plane probe with ultrasound frequency of 5 MHz. We could obtain satisfactory echograms of whole thoracic aorta except upper portion of the ascending aorta. We defined atherosclerotic lesions as an increased echo-density of the intima, protruded plaque, ulceration or aneurysm. Atherosclerotic lesions were observed in 71 of 137 patients (52%). High incidence of the atherosclerotic lesions was seen in patients with HT (72%), HC (57%) and CAD (57%), whereas incidence of atherosclerotic lesions was low (15%) in patients without HT, HC, CAD or aortic aneurysm. Atherosclerotic lesions were observed more frequently in patients aged greater than or equal to 60 years (69% vs 34%, p less than 0.001). In patients with HT or HC, atherosclerotic lesions were frequently observed even in patients younger than 60 years old (HT: 58%, HC: 53%). We concluded that HT, HC and aging were important risk factors for the atherosclerotic process in the thoracic aorta, and transesophageal echocardiography was a useful approach for the detailed estimation of atherosclerotic lesions in the thoracic aorta.

Adolescent↗
PubMed1991

[Recent trial of bronchoplasty: reconstruction of air way in the vicinity to the segmental bronchi].

With modern techniques sleeve lobectomy is the safe method of surgery for lung diseases. The reports of reconstructive surgery of more peripheral bronchi are still a few. We experienced anastomosis at the vicinity to the segmental bronchi in 11 patients with 3 central early cancers, 2 synchronous double cancers, 1 adenoid cystic carcinoma, 1 pulmonary metastasis and 4 stage III lung cancers. Operative procedures were sometimes complicated and various. Wedge segmentectomy were performed in 4 cases, of whom one patient died from pneumonia after persistent pulmonary fistula. Sleeve resectin of the segmental bronchi were performed in 7 patients, of whom one patient died from anastmotic dehiscence due to empyema thoracis induced by MRSA, another died suddenly from pulmonary infarction one month after operation. Two causes of 3 hospital deaths could not be anticipated and there was no relation with bronchoplastic procedure. Reconstructive surgery in the peripheral bronchi should be indicated for patients with central early cancer, low grade malignancy of the lung and sometimes patients with hypolung function.

Aged↗
PubMed1991

[The role of mechanical stress on the femoral head in the occurrence of femoral head lesions in spontaneously hypertensive rats].

Using spontaneously hypertensive rats (SHRs), attempts were made to decide whether or not mechanical stress on the femoral head plays a role in the occurrence of the femoral head lesions, namely, avascular necrosis and ossification disturbance. The following measures were taken to reduce mechanical stress: severing of the sciatic nerve, severing of both the sciatic and femoral nerves, and amputation of the hind limb on one side. The frequency of the femoral head lesions was highest in the control group (85%). It was lower in the sciatic nerve severance group, sciatic and femoral nerve severance group, and hind limb amputation group, in that order, showing a direct correlation with the level of mechanical stress. Moreover, histological abnormalities of the growth plate were observed frequently in the outer portion of the femoral head in SHRs with femoral head lesions. These findings indicate that mechanical stress causes an impairment of the femoral head cartilage, resulting in the obstruction of blood vessels leading to the epiphyseal nucleus of the femoral head.

Animals↗
PubMed1991

[Prognosis and survival of pT1N2 lung carcinoma undergoing pulmonary resection and mediastinal lymph node dissection].

In the past 15 years, mediastinal lymph node dissection in conjunction with pulmonary resection was performed on 39 pT1N2 patients at Tokyo Metropolitan Komagome Hospital. The patients consisted of 4 histological cell types: 26 adenocarcinomas, 5 epidermoid carcinomas, 4 large cell carcinomas and 4 small cell carcinomas. The absolute five-year survival rate for pT1 N2 patients undergoing curative resection was 52.7% which was better than that of patients with stage II non-small cell carcinoma surgically resected during the same period. This finding suggests that pT1N2 group is a special entity among pN2 lung carcinoma, that shows better survival rate than less advanced patients with respect to pathological stage (stage II).

Adult↗
PubMed1991

[Fusiform and dissecting aneurysm of the vertebrobasilar systems: differential diagnosis].

Fusiform aneurysms (FA) and dissecting aneurysms (DA) of the vertebro-basilar systems have been thought to be rare, but recently reports of these aneurysms have increased. The differential diagnosis between FA and DA is requisite for deciding therapy or for prognosis, but it is often difficult to distinguish these aneurysms even if angiographies are conducted. The authors have treated 6 cases with FA and 5 cases with DA during the past 17 years. As the initial symptom, subarachnoid hemorrhage (SAH) was noted in all 6 cases with FA. On the other hand, 2 cases of SAH, 2 cases of brain stem infarction, and 1 case of ischemic attack were noted in DA cases. The aneurysmal locations of FA were at the vertebral artery (VA) in all 6 cases, and those of DA were at the VA in 3 cases and at the basilar artery (BA) in 2 cases. As angiographic findings of DA, pearl & string signs were demonstrated in 3 cases, and retention of contrast medium was noted in 3 cases. Diagnosis of FA is comparatively easy on angiography but when angiospasm exists, it is difficult to differentiate DA from FA. Consequently, repeated angiography is recommended. MR imaging findings of 2 cases with FA were compared with those of 3 cases with DA. No abnormal findings, excepting a dilatation of the signal-void area corresponding to the arterial blood flow were shown in FA, but various abnormalities were detected in all of the 3 cases with DA. Namely, an intimal flap and a double lumen in 1 case, intra-mural hematoma in 1 case, and a hematoma adjacent to the parent artery in 2 cases were demonstrated. Thus, MR imaging was thought to be a useful means for distinguishing between FA and DA.

Adult↗