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Biomedical subjects

S Yamada

Publications and source records attributed to S Yamada.

At least 829 records · Page 46Linked to original sources
PubMed1995

[Inhibitory effect of haloperidol on evoked dopamine release from striatal slices of the rat].

Haloperidol-induced changes in evoked dopamine (DA) release from striatal slices in rats were investigated. The dose-response curves for haloperidol to changes in the evoked DA release were found to be biphasic (small doses increased the release and large doses inhibited), which were shifted to the left by longer periods of superfusion with haloperidol. This rapid tolerance or inhibition of haloperidol-induced increases in evoked DA release was reduced or attenuated by the superfusion with acetylcholine (ACh) antagonists or B-HT920 and was enhanced by ACh agonists. The microinjection of kainic acid into the rat striatum 4 days before the experiment reduced the rapid tolerance or inhibition of the haloperidol-induced increase in evoked DA release. These data indicate that intrinsic ACh neurons in the striatum may play an important role in the induction of the rapid tolerance or inhibition of haloperidol-induced increase in evoked DA release from striatal slices in rats.

Acetylcholine↗
PubMed1995

High accumulation of fluorine-18-fluorodeoxyglucose in turpentine-induced inflammatory tissue.

UNLABELLED: Fluorine-18-2-deoxy-2-fluoro-D-glucose ([18F]FDG) uptake and distribution in an experimentally induced inflammatory tissue were investigated. METHODS: Rats were subcutaneously inoculated with turpentine oil to induce inflammation and used for tissue distribution studies and autoradiography. RESULTS: Time course study of [18F]FDG tissue distribution showed that the uptake in inflammatory tissue increased gradually until 60 min and then decreased. A longitudinal study of [18F]FDG tissue distribution showed that the uptake increased progressively to a peak 4 days after inoculation and then decreased. On the fourth day postinoculation, a section of inflammatory tissue showed characteristic changes of chronic inflammation. Macro- and micro-autoradiography showed a high density of silver grains in the abscess wall consisting of an inflammatory cell layer and granulation tissue. Grain counting on micro-autoradiography of the abscess wall showed that the highest grain density was found in the marginal zone of young fibroblasts, endothelial cells of vessels and phagocytes of neutrophils and macrophages, followed by that in the neutrophil layer and granulation tissue. CONCLUSION: Our results indicate that [18F]FDG PET may be useful in detecting and monitoring chronic inflammatory processes.

Animals↗
PubMed1995

[Effects of 5-fluorouracil in shrinking residual gastric cancer: a case report].

The patient was a 79-year-old man who underwent extensive gastrectomy and Billroth-II reconstruction for gastric ulcer in 1974. He complained of heartburn in November, 1992, and endoscopy for the residual stomach revealed IIb + IIa-like lesion mainly in the posterior wall of the anastomosed site, which was diagnosed as well differentiated adenocarcinoma. As the patient refused to be operated, 150 mg/day of 5-FU was administered. For 4 months before he decided to undergo operation, 12.9 g of 5-FU was administered in total. After rehospitalization, endoscopy of the residual stomach showed shrinkage of the lesion, and biopsy revealed no malignant findings. The pathological examination after total resection of the residual stomach showed atypism, but no evidence to support malignancy. He has continued to be well without sign of recurrence for 1 year since the operation. The administration of 5-FU is widely used as preoperative adjuvant chemotherapy. This case it is rare for 5-FU to cause the disappearance or falling off of malignant cells.

Adenocarcinoma↗
PubMed1995

Methionine uptake by tumor tissue: a microautoradiographic comparison with FDG.

UNLABELLED: L-methyl-11C-methionine (11C-Met) and 2-deoxy-2-18F-fluoro-D-glucose (18F-FDG) are used for tumor diagnosis and treatment evaluation by PET. In order to examine the role of these tracers in cancer imaging, intratumoral properties of 14C-Met were studied and compared to those of 18F-FDG. METHODS: The distribution of 14C-Met in various cellular elements of two different mouse malignant tumor tissues, MH134 and FM3A, was analyzed serially using microautoradiography within a period of 120 min after injection of the tracer. RESULTS: Carbon-14-Met and 18F-FDG showed different distributions in tumor tissue. Carbon-14-Met uptake by the tumor was mostly by viable cancer cells. The uptake by macrophages and other cellular components was low. The uptake was higher in the highly proliferative tumor but did not reflect protein synthesis. The rapid and slow growing tumors demonstrated that 14C-Met uptake ratio was lower than that of 18F-FDG, reflecting de novo DNA synthesis ratio. CONCLUSION: Carbon-14-Met uptake represents the presence of viable cancer cells. Carbon-11-Met may be suitable for treatment evaluation of individual tumors but not growth rates of different tumors. Fluorine-18-FDG reflects tumor-host immune system reaction and is an excellent tool for pretreatment evaluation of tumors and determination of tumor proliferative activity.

Animals↗
PubMed1995

Surgical management for lymph node recurrence of resected fibrolamellar carcinoma of the liver: a case report.

Fibrolamellar carcinoma of the liver (FLC), which is very rare in Japan, is reported to be frequently accompanied by lymph node metastasis in Europe and the United States. We describe a 22-year-old man with recurrent FLC in the lymph nodes after undergoing partial hepatectomy. He underwent a second operation for removal of recurrent lymph node tumors in the mediastinum and abdominal cavity one year after initial surgery. However, a third operation became necessary seven months later, because of recurrence in a lymph node in the abdominal cavity. We discuss the management of lymph node metastasis from FLC.

Adult↗
PubMed1995

[Clinical outcome of radical prostatectomy and pelvic lymph node dissection].

Between September, 1987 and September, 1993, a total of 44 consecutive patients had undergone radical retropubic prostatectomy and pelvic lymphadenectomy for the treatment of prostate cancer. The patients were between 56 and 77 years (mean, 68 years). Eleven patients had clinical state A2 disease, 21 had stage B disease, and 12 had stage C disease. Fourteen of the 44 patients (32%) had positive lymph node metastases. The 5-year survival rate for patients with pT1, pT2 and pT3 was 100%, 71% and 87%, respectively. It was 77% in patients with positive node disease and 90% in patients with negative node disease. The 5-year disease-free survival rate for patients with pT1, pT2 and pT3 was 82%, and 78%, respectively. It was 54% in patients with positive node disease and 88% in patients with negative node disease. In 14 positive node patients, metastases were located in obturater nodes in 8 patients (57%), hypogastric nodes, in 6 patients (43%), external iliac nodes in 6 patients (43%), common iliac nodes in 4 patients (29%) and presacral nodes in 2 patients (14%). We confirmed that radical retropubic prostatectomy is effective treatment for locally confined prostate cancer and removal of obturater, hypogastric lymph nodes and the internal chain of external iliac lymph nodes is important in detecting metastases.

Aged↗
PubMed1995

[Effects of weight training on muscle strength and exercise capacity in patients after myocardial infarction].

The effect of combined aerobic and weight training on indexes of muscle strength and exercise capacity was investigated in 59 patients after myocardial infarction. Subjects were randomly assigned into three groups: group I performing combined aerobic and weight training (n = 22), group II performing ordinary aerobic training alone (n = 19) and group III not performing physical training (n = 18). Before and after the training, isokinetic knee extension strength was measured and cardiopulmonary exercise testing was performed. Physical training was prescribed for 8 weeks. Weight training of knee extensors was performed at 60% of 1 repetition maximum and aerobic training was prescribed at the heart rate of anaerobic threshold (AT) level. After 8 weeks, the increase of isokinetic knee extension strength was significantly greater in group I (26 +/- 14%) than group II (6 +/- 8%) and III (4 +/- 8%). Increases in peak VO2, exercise time, AT and peak O2 pulse were greater in groups I and II than group III. Furthermore, increase of exercise time was greater in group I (25 +/- 14%) than group II (16 +/- 9%). The rating of perceived exertion in submaximal exercise decreased significantly only for group I. In patients with myocardial infarction, combined aerobic and weight training is a more effective method for increasing muscle strength and exercise capacity than only ordinary aerobic training.

Aged↗
PubMed1995

A clinical evaluation of guided tissue regeneration in the treatment of class II and class III furcation bony defects.

This investigation was designed to compare the clinical efficacy of open flap/expanded polytetrafluoroethylene (e-PTFE) membrane combination therapy to open flap therapy alone in the treatment of class II and class III furcation bony defects. The efficacy was evaluated by statistical analysis of the change in values for probing pocket depth, gingival recession, and relative (probing) attachment level. The statistical analysis indicated that the guided tissue regeneration (GTR)-applied group had better efficacy than the non-applied group in the treatment of furcation bony defects. Moreover, the GTR-applied maxillary group had better efficacy than the GTR-applied mandibular group, and the GTR-applied class III group was better than the GTR-applied class II group. These results were diametrically opposed to the results from the non-applied class II group. These results were diametrically opposed to the results from the non-applied group. By histological examination, new attachment of newly formed cementum with inserting of oriented collagen fibers was noted. We also found new bone formation and partial bone repair in the former furcation bony defect.

Adult↗
PubMed1995

Effects of VA-045, a novel apovincaminic acid derivative, on rabbit basilar artery.

We investigated the effects of VA-045, an apovincaminic acid derivative, on isolated basilar artery of the rabbit. In basilar artery precontracted with histamine (10(-6) M), VA-045 (10(-9) to 10(-5) M) produced a concentration-dependent relaxation, but VA-045-induced relaxation was significantly reduced when the tonus of the mesentery was raised by isotonic high K+ (30 or 65 mM) or histamine (10(-6) M) with 15 mM K+. VA-045-induced relaxations of the basilar artery were not affected by 10 mM tetraethylammonium (TEA), 10(-6) M 4-aminopyridine, 10(-6) M charybdotoxin, 10(-7) M apamin and 10(-6) M glybenclamide. VA-045-induced relaxation was not influenced by 10(-5) M methylene blue. These results suggest that increased open probability of potassium channels, which are not Ca(2+)-dependent K(+)-channels or TEA- or ATP-sensitive K(+)-channels, may be involved in VA-045-induced relaxation of basilar artery.

Animals↗
PubMed1995

[Catamenial pneumothorax with diaphragmatic and visceral plural endometriosis].

A 47-year-old woman was admitted to our hospital because of two episodes of right pneumothorax. After continuous suction through a thoracic drain, a computerized tomographic scan showed that air was still trapped between lung lobes. Video-assisted thoracic surgery revealed a bulla on the visceral pleural of the upper lobe (S2) and several dark-red spots and white-coated lesions surrounding a defect of the diaphragm. The involved portions of the diaphragm and of the lung were excised. Microscopic examination of the excised specimens showed endometriosis. Catamenial pneumothorax may be caused by intrathoracic endometriosis, but very few cases in which pulmonary or visceral pleural endometriosis was demonstrated histologically have been reported.

Blister↗
PubMed1995

Vibration syndrome and autonomic nervous system.

It is well known that hand-arm vibration affects the hand and arm which are directly exposed to vibration. However, through the sympathetic nervous system, hand-arm vibration can affect the foot which is not directly exposed to vibration. Hand-arm vibration activates the sympathetic nervous system, and induces vasoconstriction in the four extremities. And patients with vibration syndrome have circulatory disturbances of the foot as well; some patients had Raynaud's phenomenon of both fingers and toes, those with VWF were likely to complain of coldness in the feet as well as the hands, and had low skin temperature of the fingers and toes. In addition, arterial pathological changes like medial muscular hypertrophy have been observed in both fingers and toes of the patients. Prolonged repeated vasoconstriction of the foot induced by hand-arm vibration through the sympathetic nervous system is supposed to result in arterial changes like medial muscular hypertrophy in the foot and eventually circulatory disturbances of the feet. Hyperactivity of the sympathetic nervous system to cold, which is shown in patients with VWF, also probably contributes to the foot disturbances. The effect of hand-arm vibration through the sympathetic nervous system should be considered in hand-arm vibration syndrome.

Cumulative Trauma Disorders↗
PubMed1995

Digital nerve conduction velocity for evaluation of peripheral nerve impairments in vibration syndrome.

In order to evaluate peripheral nerve impairments in vibration syndrome, sensory nerve conduction velocity (SCV) in the digital segment of the median nerve was measured by applying electrical stimulation to the wrist and recording from two pairs of electrodes attached to the middle finger. Fractionated SCVs were also measured in the palm-to-finger, wrist-to-palm, and elbow-to-wrist segments of the median nerve. Subjects were 65 patients with vibration syndrome and 48 healthy controls of similar age. SCVs in the digital nerve segment were significantly slower in the patients than in the controls. Significant slowing was also found in the wrist-to-palm segment. SCVs in the palm-to-finger and elbow-to-wrist segments did not differ between the two groups. Slowed SCVs were most frequently encountered in the digital segment (38% of the patients). The slowing in the wrist-to-palm segment was found in 20% of the patients. Present findings indicate that the digital segment is most frequently affected in vibration-induced neuropathy, and measurement of SCVs in the digital segment would serve to evaluate the peripheral neuropathy in vibration syndrome.

Case-Control Studies↗
PubMed1995

Nerve conduction velocities in the lower extremities among patients with vibration syndrome.

In order to clarify the effect of vibration syndrome (VS) on the peripheral nervous system (PNS) in the lower extremities, 59 patients with VS (age 58.5 +/- 5.1 years) and 49 age-matched controls (age 57.0 +/- 5.1 years) were examined for sensory nerve conduction velocities (SCV) in the sural nerve (SSCV) and the medial plantar nerve (PSCV) in the summer of 1993 and 1994. They had not been suffering from diseases and injuries which might have affected the SCV in the lower extremities. These patients were divided into two subgroups, one with past vibration exposure to chainsaw (N = 22) and the other with past vibration exposure to rock drills and other tools (N = 37). SCVs corrected by skin temperature were subjected to statistical analysis. In PSCV a significant reduction among all patients (40.8 +/- 4.24 m/s, p < 0.01) including two subgroups (chainsaw, 39.7 +/- 4.7 m/s, p < 0.01; rock drill and others, 41.0 +/- 4.6 m/s, p < 0.01) was observed compared with those of the controls (43.2 +/- 4.31 m/s), but there was no significant reduction in SSCV. Significantly more subjects with PSCV below the standard of PSCV (ten percentile value of those of the controls) were observed among all patients (17/59, 28.8%, p < 0.05) including two subgroups (chainsaw, 7/22, 31.8%, p < 0.05; rock drill and others, 10/37, 27.0%, p < 0.05) than in the controls (4/49, 8.2%). These findings suggested that VS affected the PNS function in the lower extremities and that its mechanism was considered to mediate a circulatory disturbance, and to differ from SCV reduction in the finger.

Case-Control Studies↗
PubMed1994

Biological activities of 24-fluoro-1 alpha,25-dihydroxyvitamin D-2 and its 24-epimer.

Biological activities of two epimeric 24-fluorinated vitamin D-2 analogs, 24-fluoro-1 alpha,25-dihydroxyvitamin D-2 [24-F-1,25-(OH)2D2] and its 24-epimer [24-epi-24-F-1,25-(OH)2D2], were studied and compared with 1 alpha,25-dihydroxyvitamin D-3 [1,25-(OH)2D3] and 1 alpha,25-dihydroxyvitamin D-2 [1,25-(OH)2D2]. 24-F-1,25-(OH)2D2 was nearly as active as 1,25-(OH)2D3 and 1,25-(OH)2D2 both in regulating calcium metabolism in vivo including bone mineral mobilization and intestinal calcium transport and in inducing differentiation of HL-60 cells. While 24-epi-24-F-1,25-(OH)2D2 showed distinct properties in these two types of the actions. Though the 24-epimer was nearly as potent as 1,25-(OH)2D3 in inducing differentiation of HL-60 cells, it showed little activity in regulating calcium metabolism in vivo. The fluorine atom introduced at the 24-position of either 1,25-(OH)2D2 or its 24-epimer had no potentiating effect. This is in sharp contrast with the cases of 24- and 26,27-multifluorinated analogs of active vitamin D-3.

Animals↗
PubMed1994

Accelerated bone marrow recovery from radiation damage in etoposide-pretreated mice.

PURPOSE: Etoposide inhibits the activity of Topoisomerase II, and possesses radiosensitizing effects on cultured cells. We showed that pretreatment of mice with etoposide 1 day before whole-body irradiation (WBI) had a protective effect against radiation-induced bone marrow death. The number of endogenous colony-forming units (CFU-S) surviving in WBI mice was significantly increased by pretreatment with etoposide. The purpose of the present study is to clarify mechanisms underlying the protective activity of etoposide against radiation-induced bone marrow damage. METHODS AND MATERIALS: The spleen colony-forming cells (CFU-S) of femoral marrow were assayed by the method of Till and McCulloch. The proliferative state of CFU-S was assessed using the technique of Hodgson. The reduction in exogenous CFU-S after hydroxyurea injection was used to determine the fraction size of S-phase in CFU-S. RESULTS: Etoposide pretreatment did not modify the cell survival parameters of exogeneous CFU-S when bone marrow cells were assayed immediately after WBI. Recovery of CFU-S in femoral marrow started earlier in mice receiving etoposide pretreatment than in the radiation alone group. Administration of hydroxyurea revealed that the accelerated recovery of CFU-S was due to an increased population of S phase cells, suggesting etoposide pretreatment shortened generation time of CFU-S. CONCLUSIONS: The mechanism for the radioprotection appears to be accelerated proliferation of survived bone marrow cells rather than a change in cellular sensitivity to radiation.

Animals↗