Biomedical subjects

A Morimoto

Publications and source records attributed to A Morimoto.

At least 19 recordsLinked to original sources

PubMed2000

Involvement of central beta-adrenoceptors in the tachycardia induced by water immersion stress in rats.

The purpose of the present study was to investigate whether central beta-adrenoceptors are involved in stress-induced cardiovascular responses in rats. Using a biotelemetry system, blood pressure and heart rate were measured at rest and during stress induced by immersion in 1 cm-deep water. Intracerebroventricular (i.c.v.) injections of a nonselective beta-adrenoceptor antagonist, DL-propranolol (5 or 50 microg), significantly and dose dependently attenuated the tachycardia induced by water immersion stress (drug-induced reduction of tachycardia at 5 min after the start of stress: 61.4 +/- 13.2% for 5 microg, 72.5 +/- 8.2% for 50 microg). The same doses of DL-propranolol had no effect on the resting heart rate. Injection (i.c.v.) of a lower dose (5 microg) of D-propranolol--which has a lower potency as a beta-adrenoceptor antagonist than DL-propranolol, but a similar local anesthetic, membrane-stabilizing activity--did not attenuate the stress-induced tachycardia, although a higher dose (50 microg) did. Intravenous administration of DL-propranolol (5 or 50 microg) significantly attenuated the stress-induced tachycardia (drug-induced reduction of tachycardia at 5 min after the start of stress: 20.0 +/- 7.5% for 5 microg, 42.4 +/- 3.4% for 50 microg). However, the attenuation was much smaller than in the i.c.v. DL-propranolol-injected group. The i.c.v. injection of the 50 microg dose of DL-propranolol significantly augmented both the resting blood pressure and the pressor response to water immersion stress, whereas the lower dose (5 microg) had no effect. The i.c.v. injection of 50 microg D-propranolol also augmented, although not significantly, the resting blood pressure and the pressor response to stress. These results suggest that central beta-adrenoceptors are involved in the tachycardia induced by water immersion stress in rats.

Adrenergic beta-Antagonists↗

PubMed2000

Embolotherapy for venous impotence: use of ethanol.

PURPOSE: To evaluate the usefulness of embolotherapy with ethanol for the treatment of venous impotence. MATERIALS AND METHODS: Twenty-three patients with venous impotence underwent embolotherapy. The diagnosis of venous impotence was made by means of pharmacocavernosometry and cavernosography. After exposure of the deep dorsal penile vein, a intravenous catheter was inserted directly into the deep dorsal penile vein and advanced into just front of the preprostatic plexus. Fifty percent ethanol was injected through the catheter and the endpoint of the procedure was determined based on results of venography immediately after injection. The procedure was finished when lack of venous leakage was confirmed. RESULTS: In all patients, the deep dorsal penile vein was successfully exposed surgically, the sclerosing agent successfully injected, and the endpoint successfully achieved. Immediate clinical therapeutic effect (restoration of erection) was obtained in 20 cases (87%). No severe complications were observed during or after the procedure. The follow-up period was 6-50 months. Long-term therapeutic effect was confirmed for 18 of 23 patients (78%). CONCLUSION: The authors' findings suggest that this treatment had satisfactory short-term and long-term clinical results and that longer follow-up is necessary to confirm its safety.

Adult↗

PubMed2000

Quantitative radiographic changes in the mandible and the tibia in systemically loaded rats fed a low-calcium diet.

The combined effect of the duration of loaded physical exercise and the percentage of calcium intake on the mandible and tibia were studied in developing male rats. For the loaded exercise, rats ran on a treadmill at a rate of 12 m per min for either 1 or 2 h per day. A total of 54 4-week-old male Wistar rats were randomly assigned to one of six groups. After 4 weeks of the diet and loaded exercise, the rats were killed and their mandibles and tibia were removed. Each individual bone was assessed by radiography and the radiographs were then used for measurements of cortical thickness, bone length and bone width. All radiographic images were analyzed using a computer-based scanner image analysis system. In addition, we measured the dry weight both of the tibia and mandible. The results demonstrated that significant differences in cortical thickness, bone length, bone width, and bone weight, both of the tibia and the mandible, were detectable between the normal diet group and the low-calcium diet group. Among the normal diet groups, significant differences were found in cortical thickness, bone length, bone width, and bone weight of the tibia, whereas no significant differences in either cortical bone thickness, bone length or bone weight of the mandible were detected. In contrast, among the low-calcium diet groups, no significant differences were detected in cortical thickness, bone length, bone width or bone weight for either the tibia or the mandible. Our results suggested that systemic exercise, such as running, promote the linear dimensions and the cortical thickness of the tibia in response to local stimuli. Furthermore, sufficient calcium intake appears to be necessary to allow the effect of systemic exercise on tibial bone growth to occur. In contrast, systemic loaded exercise does not promote either bone growth or development of the mandible even under conditions of sufficient calcium intake.

Animals↗

PubMed2000

Cardiac adrenomedullin gene expression and peptide accumulation after acute myocardial infarction in rats.

Plasma adrenomedullin (AM) has been shown to increase in the early phase of acute myocardial infarction (MI). However, little information is available regarding cardiac AM synthesis after MI. Accordingly, we examined the time course of ventricular AM production and potential stimulation of AM in the infarcted and noninfarcted regions in MI rats produced by coronary artery ligation. Compared with sham-operated rats, the ventricular AM peptide level 6 h after MI increased 1.5-fold in the infarcted region and 1.7-fold in the noninfarcted region in association with increased left ventricular end-diastolic pressure (EDP). Northern blot analysis also showed marked induction of AM gene expression in the infarcted region (11-fold) and the noninfarcted region (6-fold) 6 h after MI. The AM peptide level in the infarcted region reached its peak (2. 6-fold) 1 wk postinfarction and thereafter decreased to normal. In the noninfarcted region, however, the AM level remained elevated for at least 4 wk. Immunohistochemical studies demonstrated that intense immunostaining for AM was limited to myocytes in both the infarcted and noninfarcted regions. Interestingly, the AM level in the noninfarcted region correlated positively with infarct size (r = 0. 40, P < 0.01) and EDP (r = 0.52, P < 0.001). An oral angiotensin-converting enzyme inhibitor suppressed the overproduction of AM 1 wk postinfarction in association with decreases in EDP and mean arterial pressure. In summary, cardiac AM synthesis was rapidly induced in both the infarcted and noninfarcted regions after MI. The subsequent ventricular AM in the two regions demonstrated different time-concentration curves during 4 wk after MI. AM may be synthesized predominantly by cardiac myocytes, but not by fibroblasts, at least in part, in association with increased ventricular load after MI.

Adrenomedullin↗

PubMed2000

[Study on collagen viscoelastic substance as an auxiliary agent in anterior segment surgery--ocular irritation study by replacement of the aqueous humor in rabbits].

PURPOSE: Collagen solution was assessed as a possible viscoelastic substance in anterior segment surgery, in terms of the depth of the anterior chamber and ocular irritation. METHODS: The depth of the anterior chamber of enucleated rabbit eyes was evaluated 5 minutes after injection of collagen solution. For ocular irritation test, the aqueous humor of rabbits was replaced with collagen using sodium hyaluronate (HEALON) and phosphate buffer (PB) as controls. Follow-up clinical examinations with hand-slit-lamp-microscopy, tonometry, pachymetry, and specular microscopy were performed for 7 days or 28 days, and then aqueous humor, corneal endothelium, and eye tissues were evaluated by gel electrophoresis, scanning electron microscopy, and light microscopy, respectively. RESULTS: 2.5% to 3% collagen solution was found to be optimal for maintaining the depth of the anterior chamber. No significant differences in clinical findings such as anterior chamber and corneal thickness or in biochemical and histological findings were observed among collagen-, hyaluronate- and PB-treated groups, except for intraocular pressure which was increased in the hyaluronate-treated group, but not in the collagen-treated group. CONCLUSION: Collagen specifically prepared for this study seems to be an excellent auxiliary agent for anterior segment surgery, providing an appropriate anterior chamber with little ocular irritation.

Animals↗

PubMed2000

[MR angiography of hemodialysis access fistula: evaluation before PTA procedure].

We evaluated the feasibility of MR angiography for hemodialysis fistula. Eleven patients with suspected stenosis or occlusion of an autogenous hemodialysis fistula in the forearm underwent MRA. MRA was obtained using both the 3D-PC method and 3D gadolinium contrast-enhanced (CE) method with a knee coil. The two methods were compared with DSA in seven patients. CE-MRA clearly demonstrated the entire dialysis fistula. However, signals of the stenotic area are effaced in PC-MRA. The diameter of the vessels evaluated in the CE-MRA was well correlated with angiography. CE-MRA demonstrated smaller collateral vessels more clearly than PC-MRA. CE-MRA provided useful information before the PTA procedure.

Aged↗

PubMed1999

Indication for and outcome of laparoscopy-assisted Billroth I gastrectomy.

BACKGROUND: Since 1991, laparoscopy-assisted Billroth I gastrectomy has been used for patients with early gastric cancer. The aim of this study was to clarify the outcome of 40 patients who underwent this operation and to examine the indications based on a retrospective histological study of 248 resected cases of early gastric cancer. METHODS: Operating time, blood loss, length of skin incision, and postoperative hospital stay and complications were examined using the operation records and medical charts. The presence or absence of lymph node metastasis, tumour size, site, gross type, histological type, depth of invasion, presence or absence of ulceration, and status of lymph node metastasis were investigated in 248 early gastric cancers. RESULTS: The mean operating time was 3 h and 48 min and the mean length of skin incision was 5.8 cm. Although one patient who had suffered from chronic bronchitis developed pneumonia and wound dehiscence, no other patients had a postoperative complication. The mean hospital stay after operation was 16 days and all patients were alive without recurrence at a median follow-up of 21 months. The incidence of lymph node metastasis in early gastric cancer was 2 per cent (three of 130) in mucosal cancers and 14 per cent (17 of 118) in submucosal cancers. These lesions could have been completely resected by laparoscopy-assisted gastrectomy. CONCLUSION: All 40 patients were treated successfully by laparoscopy-assisted Billroth I gastrectomy without significant complications and with no recurrences to date. Pathological study of conventionally resected stomach and lymph nodes confirmed that laparoscopy-assisted Billroth I gastrectomy would be a safe and useful operation for most early gastric cancers.

Adult↗

PubMed1999

Quality of life after laparoscopy-assisted Billroth I gastrectomy.

OBJECTIVE: To evaluate the quality of life of patients who had undergone laparoscopy-assisted Billroth I gastrectomy (LAG) for cure of cancer. SUMMARY BACKGROUND DATA: In 1994, the authors reported the first case of LAG for early gastric cancer, and this approach quickly has been adopted by Japanese surgeons. However, little is known about the subjective clinical results of this less invasive surgery. METHODS: Quality of life was estimated using the 24-item questionnaire with a scoring system of 1, 2, and 3 and was compared between 41 consecutive patients with LAG and 35 with conventional open gastrectomy. All patients underwent Billroth I gastrectomy for early gastric cancer from January 1993 to July 1997 and were alive without recurrence. RESULTS: Patients who had undergone LAG were taking a normal diet (100%) with >66% of volume at each meal (90%), showed no decreased performance status (90%), and were satisfied with their surgical results (88%). Patients with LAG, when compared with open gastrectomy, showed significantly better results with regard to weight loss, difficulty in swallowing, heartburn and belch, early dumping syndrome, and total score. LAG was better accepted by the patients. CONCLUSIONS: Quality of life after Billroth I gastrectomy was significantly better in patients in whom a laparoscopic technique was used than in those who underwent a conventional method. LAG is less invasive and better accepted by patients and is the procedure of choice for the treatment of early gastric cancer.

Aged↗

PubMed1999

Proximal gastrectomy and gastric tube reconstruction for early cancer of the gastric cardia.

BACKGROUND: Advances in diagnostics and techniques have increased the number of detections of early cancer of the gastric cardia. The aim of this report is to describe a new technique of proximal gastrectomy and gastric tube reconstruction using an autosuture stapler. METHODS: At operation, the upper part of the stomach was fully mobilized, and the abdominal esophagus was transected. The stomach was cut between the points of the distal three fourths of the lesser curvature and a half of the greater curvature, and a gastric tube measuring 20 cm in length and 4 cm in width was made. A circular stapler was inserted through a stapled line, and direct anastomosis between the esophagus and gastric tube was completed. RESULTS: When compared with the patients who underwent proximal gastrectomy and jejunal interposition, those who underwent gastric tube reconstruction showed a significantly shorter operation time. All 3 patients who underwent proximal gastrectomy and gastric tube reconstruction recovered uneventfully and took foods satisfactorily. Good passage through the gastric tube was recognized on roentgenography, and reflux esophagitis or stomal ulcer was not found on fiberscopy. CONCLUSIONS: We believe the procedure is technically simple and safe, and provides good postoperative results in patients with early cancer of the gastric cardia.

Adenocarcinoma, Mucinous↗

PubMed1999

Ventricular adrenomedullin levels correlate with the extent of cardiac hypertrophy in rats.

We investigated the pathophysiological significance of adrenomedullin (AM) in the development of left ventricular hypertrophy (LVH). LVH was produced by aortic banding (AB) in rats. The left ventricular weight/body weight (LV/BW) ratio, ventricular AM peptide and mRNA levels, and hemodynamics were measured at 1, 3, 7, and 21 days after the operation. Both LV/BW ratio and ventricular AM levels showed a significant increase from 1 day after the operation in the AB rats versus the sham-operated rats. Both increased in a time-dependent manner. The ventricular AM levels correlated with the LV/BW ratio (r=0.76, P<0.01). The AM mRNA levels were highly expressed at 1 day after the operation in the AB rats but showed no difference from 3 to 21 days after the operation between the AB and sham groups. The plasma AM levels showed a peak at 1 day after the operation in both groups. Then, we treated AB rats with an angiotensin-converting enzyme inhibitor (quinapril) in 2 doses (1 and 10 mg. kg-1. d-1) for 21 days. The quinapril treatment attenuated similarly both the LV/BW ratio and the ventricular AM levels. We also assessed the effects of AM and hydralazine administration for 7 days on the LV/BW ratio and hemodynamics of AB rats. Both AM and hydralazine administration reduced the blood pressure by approximately 10% compared with the nontreated AB rats, but a reduction of the LV/BW ratio was observed only in the AM-treated group (P<0.05). These results suggest that ventricular AM levels are elevated by chronic pressure overload in a time-dependent manner concomitant with the extent of LVH and that AM may play a pathophysiological role in the development of LVH in chronic pressure overload.

Adrenomedullin↗

PubMed1998

Sympatho-adrenal involvement in methamphetamine-induced hyperthermia through skeletal muscle hypermetabolism.

We investigated the involvement of the sympatho-adrenal axis in the hyperthermia induced by methamphetamine by using a biotelemetric system. The intraperitoneal injection of methamphetamine (1 mg/kg) induced hyperthermia preceded by an increase in oxygen consumption in freely moving rats. The hyperthermic effect of methamphetamine was completely blocked by chemical sympathectomy with 6-hydroxydopamine (50 mg/kg, i.p.). Adrenalectomy, but not adrenal demedullation, prevented the hyperthermia. In adrenalectomized rats, dexamethasone supplementation (0.5 mg/kg, s.c.) restored the methamphetamine-induced hyperthermia. Furthermore, dantrolene (1 or 2 mg/kg, i.v.), which blocks Ca2+ release from the sarcoplasmic reticulum in skeletal muscle, attenuated the hyperthermia. These results suggest that methamphetamine stimulates norepinephrine release from sympathetic nerve terminals, which then enhances thermogenesis in skeletal muscle under the permissive action of glucocorticoids.

Adrenal Glands↗

PubMed1998

Detection of a tryptophan radical as an intermediate species in the reaction of horseradish peroxidase mutant (Phe-221 --> Trp) and hydrogen peroxide.

The crucial reaction intermediate in the reaction of peroxidase with hydrogen peroxide (H2O2), compound I, contains a porphyrin pi-cation radical in horseradish peroxidase (HRP), which catalyzes oxidation of small organic and inorganic compounds, whereas cytochrome c peroxidase (CcP) has a radical center on the tryptophan residue (Trp-191) and oxidizes the redox partner, cytochrome c. To investigate the roles of the amino acid residue near the heme active center in discriminating the function of the peroxidases in these two enzymes, we prepared a CcP-like HRP mutant, F221W (Phe-221 --> Trp). Although the rapid spectral scanning and stopped-flow experiments confirmed that the F221W mutant reacts with H2O2 to form the porphyrin pi-cation radical at the same rate as for the wild-type enzyme, the characteristic spectral features of the porphyrin pi-cation radical disappeared rapidly, and were converted to the compound II-type spectrum. The EPR spectrum of the resultant species produced by reduction of the porphyrin pi-cation radical, however, was quite different from that of compound II in HRP, showing typical signals from a Trp radical as found for CcP. The sequential radical formation from the porphyrin ring to the Trp residue implies that the proximal Trp is a key residue in the process of the radical transfer from the porphyrin ring, which differentiates the function of peroxidases.

Calcium↗

PubMed1998

Suppression of tumorigenicity of glioblastoma cells by adenovirus-mediated MMAC1/PTEN gene transfer.

Mutated in multiple advanced cancers 1/phosphatase and tensin homologue (MMAC1/PTEN) is a novel tumor suppressor gene candidate located on chromosome 10 that is commonly mutated in human glioblastoma multiforme and several other cancer types. To evaluate the function of this gene as a tumor suppressor, we constructed a replication-defective adenovirus (MMCB) for efficient, transient transduction of MMAC1 into tumor cells. Infection of MMAC1-mutated U87MG glioblastoma cells with MMCB resulted in dose-dependent exogenous MMAC1 protein expression as detected by Western blotting of cell lysates. In vitro proliferation of U87MG cells was inhibited by MMCB in comparison to several control adenoviruses at equal viral doses, implying a specific effect of MMAC1 expression. Anchorage-independent growth in soft agar was also inhibited by MMCB compared to control adenovirus. Tumorigenicity in nude mice of transiently transduced mass cell cultures was then assessed. MMCB-infected U87MG cells were almost completely nontumorigenic compared to untreated and several control adenovirus-treated cells at equal viral doses. These data support an in vivo tumor suppression activity of MMAC1/PTEN and suggest that in vivo gene transfer with this recombinant adenoviral vector has a potential use in cancer gene therapy.

Adenoviridae↗

PubMed1998

Diffuse bilateral thalamic astrocytomas as examined serially by MRI.

We report the case of a 13-year-old girl with diffuse bilateral thalamic astrocytomas. Incoordination was observed at the onset. Cranial computed tomography (CT) showed enlarged thalami, and magnetic resonance imaging (MRI) revealed these lesions to be symmetrically enlarged with high intensity on the T2-weighted image. Owing to these atypical findings in the neuroimaging studies, we had difficulty in making the correct diagnosis of a brain tumor. After the diagnosis of diffuse bilateral thalamic astrocytomas was obtained, we performed hyperfractionated radiotherapy followed by chemotherapy. Radiation therapy was effective for a while, but the girl's condition deteriorated again and she died 8 months after admission. Although diffuse bilateral thalamic astrocytomas are difficult to diagnose because they do not resemble most other neoplasms on neuroimaging studies, pediatricians should keep this entity in mind in order to arrive at a precise and prompt diagnosis.

Adolescent↗

PubMed1998

Perigastric lymph node status as a prognostic indicator in patients with gastric cancer.

BACKGROUND: The extent of lymph node dissection and histological examination of dissected lymph nodes varies among countries, which leads to the erroneous nodal stage and different surgical results in gastric cancer (stage migration, 'Will Rogers effect'). The aim of this study was to clarify the prognostic significance of the number of positive perigastric lymph nodes, which could be evaluated simply after D1 gastrectomy. METHODS: A consecutive series of 106 patients with histologically node-positive gastric cancer treated by radical gastrectomy and lymph node dissection (D2 or D3) was studied. The number of metastatic perigastric nodes (level I, nos 1-6) was examined, and its influence on the survival of patients was analysed. RESULTS: The overall 5-year survival rate was 50.9 per cent; the 5-year survival rate was significantly decreased when positive perigastric nodes exceeded six (62 per cent for one to six nodes versus 23 per cent for seven or more nodes, P< 0.001). Tumours having one to six positive perigastric nodes compared with those having seven or more positive perigastric nodes were more likely to have a size less than 4 cm (29 per cent versus one of 30, P< 0.001), grossly localized type (45 per cent versus seven of 30, P=0.042), absence of serosal invasion (32 per cent versus none of 30, P=0.002) and metastasis limited to the perigastric lymph nodes (70 per cent versus seven of 30, P < 0.001). CONCLUSION: The results indicate that the number of positive perigastric nodes correlates with tumour progression and patient survival. This parameter is a simple and useful prognostic indicator for node-positive gastric cancer, and is available not only for D2 and D3 gastrectomy but also for D1 gastrectomy.

Adult↗

PubMed1998

Dental treatment of a prospective recipient of a liver transplant: a case report.

A protocol to treat a carious condition in a young girl scheduled to receive a liver transplantation is described. Teeth with serious caries were filled with amalgam. Those teeth with pulp exposure were extracted. To stop bleeding, sutures and a surgical splint with a periodontal pack were used. All procedures were performed as rapidly as possible to minimize stress. Antibiotics were used sparingly. By improving the oral health of transplant recipients, the chances that the transplanted liver will become infected are much reduced, increasing the likelihood of a successful surgical outcome.

Alagille Syndrome↗

PubMed1998

[Optimal scan parameters of MRCP using HASTE].

For improving the image of fine structures on MRCP, optimal scan parameters were assessed by water-filled phantom using HASTE sequence. Spatial resolution and Contrast-to-Noise Ratio (CNR) were measured at various FOVs and slice thicknesses with a body array coil. High spatial resolution was provided at less than 25 cm in FOV, and narrow phantom under 1 mm in diameter was obscured at more than 30 cm in FOV. Highest CNR was provided at 3 mm slice thickness on a 1.5 T unit, and at 4 mm slice thickness on a 1.0 T unit. Narrow phantom under 1 mm in diameter was depicted clearly on a 1.5 T unit, but irregularly on a 1.0 T unit. Taking required spatial resolution and CNR into consideration, we should determine optimal FOV and slice thickness for the assessment of anatomic details on MRCP.

Biliary Tract↗

PubMed1998

[MR cholangiopancreatography using respiratory triggered half-Fourier RARE technique].

We evaluate the usefulness of MRCP using respiratory triggered HASTE technique in 68 patients. Eleven subsequent slices were obtained for MRCP. To determine the optimal trigger rate, MRCP with various trigger rates were compared in 25 patients. Respiratory triggered MRCP and breath hold MRCP were compared in 68 patients. Respiratory triggered MRCP was also performed in 3 infants. The optimal trigger rate was 10%. In 17 patients who could not stop their breath for 10 seconds, respiratory triggered MRCP were better than breath hold MRCP in 14 (82%) for the source images and in 17 (100%) for the MIP images. Respiratory triggered MRCP could depict cystic duct and main pancreatic duct even in 14 month infant. MRCP with high spatial resolution could be obtained with respiratory triggered HASTE technique in critically ill, or non-cooperative patients.

Adult↗