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Biomedical subjects

T Mizuta

Publications and source records attributed to T Mizuta.

At least 37 records · Page 2Linked to original sources
PubMed1998

Case report: a long-term survivor of jejunal leiomyosarcoma with liver metastasis: effective transcathetel arterial embolization for hepatic metastatic foci.

We report a case of jejunal leiomyosarcoma with liver metastases in a 52-year-old Japanese male. An echogram demonstrated multiple cystic liver masses in April 1991. The diagnosis of metastatic leiomyosarcoma was made on the basis of characteristic hepatic angiography images and liver biopsy findings. The jejunal leiomyosarcoma was resected and unresectable liver metastatic foci were treated repeatedly with transcathetel arterial embolization. Transcathetel arterial embolization was considered to be effective in this case as the patient survived 4 years and 9 months after the first treatment.

Catheterization↗
PubMed1998

Differential expression of laminin receptors in human hepatocellular carcinoma.

BACKGROUND: Laminin receptors are involved in cell-extracellular matrix interactions in malignant cells that show invasion and metastasis. Hepatocellular carcinoma frequently shows early invasion into blood vessels, and intrahepatic and extrahepatic metastases. However, the role of laminin receptors in hepatocellular carcinoma is unknown. AIMS: To examine the expression of mRNA for laminin receptors and their isoforms in hepatocellular carcinoma. METHODS: The expression of several laminin receptors, including alpha1 integrin, alpha6 integrin and its isoforms alpha6A and alpha6B, beta1 integrin and its isoforms beta1A and beta1B, and 32kD/67kDa laminin binding protein was examined in human hepatocellular carcinomas and non-cancerous liver tissues using the reverse transcription polymerase chain reaction. RESULTS: Alpha6 Integrin, beta1 integrin, and laminin binding protein showed notably increased expression in hepatocellular carcinoma, compared with non-cancerous liver tissue, although the alpha1 integrin did not show a significant change. Furthermore, beta1B integrin, a splicing variant of beta1 integrin, was overexpressed in hepatocellular carcinoma while the beta1A integrin isoform did not show significant changes between hepatocellular carcinoma and surrounding non-cancerous liver tissue. CONCLUSIONS: The differential upregulation of laminin receptors and their splicing isoforms was shown in hepatocellular carcinoma, suggesting that certain laminin receptors and their isoforms may be involved in the development and progression of hepatocellular carcinoma.

Aged↗
PubMed1998

Preliminary study on the effect of rocking on activities of persons with severe mental and physical handicaps.

In this preliminary observation, a group of seven mentally and physically handicapped persons of chronological ages ranging from 15.4 yr. to 26.8 yr. experienced 15 sec. of physical rocking. For the further analysis, the poststimulus periods were classified into either those when the subjects' spontaneous head, mouth, and body movements had increased from the prestimulus period or those decreased. The median heart rates recorded in the poststimulus period were not significantly different from those in the prestimulus period on trials on which there was an observable increase in the rates of spontaneous head, mouth, and body movements; however, the median heart rates decreased during those trials on which a decrease in the rates of the movements occurred. Since it is said that rocking heightens arousal of persons with mental and physical handicaps, it is suggested that spontaneously emitted, aimless head, mouth, and body movements attributed to low arousal were reduced by heightened arousal rather than by a decline in participants' activities.

Adolescent↗
PubMed1997

Increased nitric oxide levels in exhaled air of rat lung allografts.

In organ transplantation nitric oxide has been reported to be involved in allograft rejection. We examined in a rat lung transplantation model whether nitric oxide is overproduced in acute rejection and can be detected in exhaled air. Thirteen rat right lung transplants were separated into three groups: group 1 (n = 5), untreated allografts (Brown-Norway [RT1n] to Lewis [RT1l]); group 2 (n = 4), cyclosporine-treated allografts; and group 3 (n = 4), isografts (Lewis to Lewis). We examined exhaled nitric oxide levels with a chemiluminescence analyzer and chest roentgenograms on days 2 through 5. Histologic samples were obtained on days 3 and 5. On day 5, the recipients were killed and we measured exhaled nitric oxide from the right and left lungs separately. Blood samples were also obtained for measurement of serum nitrite/nitrate. The exhaled nitric oxide level in untreated allografts increased significantly from day 5 (63.9 +/- 39.2 ppb, p = 0.0095) and was significantly higher than that in treated allografts (9.1 +/- 1.6 ppb) (p = 0.0085) and isografts (6.9 +/- 0.5 ppb) (p = 0.0068). The nitric oxide level in untreated allografts (826.5 +/- 416.1 ppb) was 75 times as high as that from the contralateral normal left lungs (11.2 +/- 2.6 ppb) (p = 0.0118). The level of exhaled nitric oxide correlated significantly with the histologic rejection grade (p = 0.0001). There was no significant difference in the serum nitrite/nitrate levels between allografts and isografts. These data suggest that increased exhaled nitric oxide levels might reflect acute rejection in lung transplants.

Animals↗
PubMed1997

[The role of surgery for chronic empyema of the advanced ages].

Chronic empyema, a sequelae of pulmonary tuberculosis, is now a only tuberculosis-related disease which was remained to be treated surgically. The candidates who have basically poor respiratory function are now attained advanced age. Over a 15 years period (1980-95), 22 patients 70 years of age or older underwent surgical intervention for chronic empyema at our hospital. There were 17 men and 5 women, ranging from 70 to 80 years of age (median age 75.0). They were 15.3% of all 145 surgically treated patients during same period. The empyema continued latent from 25 to 58 years (average 39.8 years). On admission they complained of productive cough (9), fever (9), hemosputam (5) and mass on the chest wall. Their Hugh-Johnes classification for dyspnea was I.: 4, II.: 6, III.: 11, IV.: 1 respectively. Their %VC ranged from 31.5 to 79.0 (average 54.8). In fifteen patients, tubercle bacilli (5), aspergillus (3) and other bacteria (9) were discovered in the empyema space. Surgical procedures consisted of 1 pneumonectomy (4.5%), 12 decortication or curettage of empyema wall (54.5%), 4 extraperiosteal air plombage (18%) and 5 other procedures (muscle or omental plombage, thoracoplasty, fenestration and others) (22.7%). There were no operative death and no lethal postoperative complication. In contrast, lethal postoperative complications such as GVIID, MOF and gastrointestinal bleeding occurred in the younger group. There were 2 cases of late respiratory failure in 70 years or older and 6 cases in younger group. Seventy-four years man who, preoperative %VC 33.0, underwent pneumonectomy died of asphyxia 6 month postoperatively. Another 74 years man who, preoperative %VC 76.1, developed respiratory failure after relapse of pulmonary tuberculosis. Four patients of younger group who developed late respiratory failure had all received thoracoplasty as a second operation. Other 2 patients, preoperative %VC 33.0 and 27.4 respectively, had undergone pneumonectomy. The risk of lethal postoperative complication or late respiratory failure were dependent mainly on preoperative respiratory function or surgical procedure selected rather than the age of patients.

Age Factors↗
PubMed1997

Concomitant cardiac and pulmonary operation. Pulmonary mechanics and outcome of phrenic nerve injury.

OBJECTIVE: We describe the postoperative respiratory failure due to the phrenic nerve injury in the setting of concomitant cardiac and pulmonary operation. EXPERIMENTAL STUDY: Prospective study. SETTING: Department of Cardiac and Thoracic Surgery Osaka University Medical School. PATIENTS AND INTERVENTIONS: From January 1984 to December 1993, 5 patients (1.4%) underwent the concomitant cardiac and pulmonary operation out of 359 patients who received surgical treatment for lung cancer at our institution. MEASURES AND RESULTS: Three (60%) out of 5 patients required prolonged mechanical ventilation despite the absence of cardiac complication, lung edema or pneumonia. Diaphragm function and work of breathing were measured in two patients before and after weaning from mechanical ventilation. Phrenic nerve dysfunction was consistent with the result that trans-diaphragmatic pressure (delta Pdi) was low, a ratio of gastric to esophageal pressure swing (delta Pga/delta Pes) was abnormally negative, and work of breathing (WOB) was high. Phrenic nerve function restored associated with clinical improvement. CONCLUSIONS: Diaphragm dysfunction and an increase in work of breathing may be potential causes of respiratory failure in patients after concomitant cardiac and pulmonary operation. This compromise in respiratory mechanics should not be overlooked in the postoperative care, which may lead to the best management in postoperative respiratory care.

Aged↗
PubMed1996

Right lung transplantation followed by left pneumonectomy in the rat.

OBJECTIVE: To develop a rodent lung transplant model which depends on graft function for survival, total microsutureless lung transplantation was carried out and followed by contralateral native pneumonectomy in the rat. METHODS: Total non-microsuture right lung transplantation was undertaken using a cuff technique with anastomotic areas twice as big as those for the left lung transplantation. Inbred rats received either right (n = 10) or left lung isograft (n = 10) with non-microsuture techniques and underwent contralateral native pneumonectomy 2 weeks later to test the function of the grafted lung. RESULTS: While none of the left lung recipients could be disconnected from the respirator after right pneumonectomy, eight of ten right lung recipients tolerated left pneumonectomy, increased body weight and regained exercise capacity (oxygen uptake 49 +/- 4 ml/kg per min) comparable to that of control rats undergoing right hilar stripping and left pneumonectomy. CONCLUSIONS: The results suggest that the grafted right lung, but not the left lung, allows survival, growth and exercise of the recipient. Right lung transplantation followed by native left pneumonectomy may serve as a physiologic model of lung transplantation in the rat.

Animals↗
PubMed1996

Characterization of monoclonal antibodies recognizing human merosin and their use in affinity purification of native merosin.

Two monoclonal antibodies (MAbs) to human placenta laminin (pl-LAM), 1D8 (IgG1) and 6G5 (IgG2b) were generated and shown by ELISA and immunoblot analysis to recognize only native pl-LAM, but not denatured, reduced pl-LAM or mouse EHS laminin. Intact pl-LAM was easily isolated and purified in large scale from human placenta by 1D8-conjugated affinity chromatography. Electrophoretic analysis of the purified pl-LAM revealed the presence of a major 750-kDa component composed of 320-, 220-, and 200-kDa polypeptides and a minor 800-kDa component composed of 320-, 240-, and 220-kDa polypeptides. Neither molecule had a 400-kDa component corresponding to the A chain. It has already been shown that the 320-kDa polypeptide is identical to the M chain of human merosin (Hori et al. J. Biochem. 1994;116:1212-1219). Electron microscopy revealed that isolated merosin was composed of three short arms and one long arm. By immunohistochemistry, MAbs showed positive staining in human adult kidney and liver. These results indicate that these MAbs recognize only native merosin and can be used to study merosin structure and function by rapid purification of native merosin and by immunohistochemical analysis.

Animals↗
PubMed1996

Carcinoid tumor of the gall bladder.

A classical carcinoid tumor, measuring 11 x 17 mm, was found in a 41-year-old woman in the neck of the gall bladder. The lesion infiltrated the muscular layer of the gall bladder wall. Histologically, the tumor was positive for only Grimelius and chromogranin A stains. In a literature search, approximately half of the tumors reported as gall bladder carcinoid tumor appear to be actually endocrine cell carcinomas, which are completely different from classical carcinoid tumors with respect to size, metastasis and prognosis. These carcinomas should not be termed as carcinoid tumors from both the clinical and histological points of view, and should be clearly distinguished from benign lesions when reported.

Adult↗
PubMed1996

Exercise performance of rats after isogenic left or right lung transplantation followed by contralateral pulmonary artery ligation.

BACKGROUND: After single lung transplantation for pulmonary hypertension, large mismatches in ventilation/perfusion distribution persist late after transplantation. The larger graft volume of the transplanted lung after transplantation, the better the exercise performance. Because the right lung is larger in volume than the left, we compared the left single lung transplant with the right single lung transplant regarding exercise performance with an animal model. METHODS: To simulate significant ventilation/perfusion imbalance observed after single lung transplantation for pulmonary hypertension, we transplanted isogenic left or right pulmonary grafts to normal rats, and the contralateral pulmonary artery was ligated 2 weeks after transplantation. The treadmill test was performed weekly until 6 weeks after transplantation to measure maximum tolerated running speed and maximum oxygen uptake. RESULTS: Graft vital capacity of left and right pulmonary grafts were 4.5 +/- 0.43 ml (37% +/- 3.7% of recipient's predicted vital capacity) and 7.8 +/- 0.34 ml (63% +/- 2.4%), respectively (p < 0.01). Maximum tolerated speeds of left and right single lung transplants were 8 +/- 7.6 and 29 +/- 2.2 m/min, respectively, at 6 weeks after transplantation (p < 0.01). Maximal oxygen uptake values of left and right single lung transplants were 34 +/- 12.0 and 65 +/- 3.8 ml/kg/min, respectively (p < 0.01). CONCLUSIONS: Results suggest that right lung transplantation is superior to left lung transplantation for pulmonary hypertension in terms of exercise performance in this animal model.

Animals↗
PubMed1996

Decreased vascular sensitivity after acute exercise and chronic exercise training in rat thoracic aorta.

The effects of acute and chronic physical exercise on the sensitivity of isolated aorta to norepinephrine were investigated. After chronic exercise, the EC50 values for norepinephrine increased 3.1-fold and 2.3-fold in endothelium-intact and in endothelium-denuded aorta, respectively. The attenuated sensitivity of aorta to norepinephrine after chronic exercise was still evident in endothelium-denuded aorta, but to a lesser extent than in endothelium-intact aorta. After acute exercise, in control rats, the EC50 values increased 7.8-fold and 5.4-fold in endothelium-intact and endothelium-denuded aorta, respectively. The attenuated sensitivity of aorta to norepinephrine after an acute exercise was still evident in endothelium-denuded aorta. In trained rats, the EC50 values increased 2.3-fold and 2.6-fold in endothelium-intact and endothelium-denuded aorta, respectively. Thus, acute exercise was less effective in trained than in control rats. No significant difference in 60 mM KCl-induced tension between control and trained rats was observed with or without endothelium after acute and chronic exercise. The results suggest that levels of endothelium-dependent releasing factor may increase in response to norepinephrine after acute and chronic exercise. In addition, the attenuated sensitivity of aorta to norepinephrine after acute and chronic exercise may also result from the change(s) in the receptor sites. However, the degree of desensitization caused by acute exercise was less in the rats adapted to chronic exercise than in the sedentary control rats.

Adrenergic alpha-Agonists↗
PubMed1995

Effect of ischemic injury on subsequent rat lung allograft rejection.

BACKGROUND: It has been suggested that the frequency and severity of allograft rejection may be related to the degree of allograft ischemia. The purpose of this study was to determine whether ischemic insult correlates with lung allograft rejection. METHODS: Forty-eight left lung transplants were performed from Lewis donor rats into F344 recipient rats. Allografts were divided into two groups based on the degree of ischemic insult. Transplantation was performed immediately (group 1, minimum injury) or after 18 hours of cold (1 degree C) preservation (group 2, severe injury). Allografts were evaluated radiographically based on aeration scores (0 = opaque to 6 = normal). Animals were randomly sacrificed on days 7, 14, or 21 for histologic and immunohistochemical evaluation of rejection. RESULTS: On postoperative day 3, significantly lower aeration score was demonstrated in group 2 (3.69 +/- 1.71) compared to group 1 (5.0 +/- 1.09) (p < 0.05) as a result of the difference in reperfusion injury. However, by day 7 and thereafter, there was no significant difference. Histologic rejection was present by day 7 and peaked at day 14 with no significant difference between groups. There was also no difference in CD4+, CD8+ infiltrating lymphocyte population or expression of class II major histocompatibility complex antigen on bronchial epithelium. CONCLUSIONS: We conclude that ischemic injury in rat lung allograft does not correlate with the onset or severity of rejection.

Animals↗
PubMed1995

Free radical-mediated vascular injury in lungs preserved at moderate hypothermia.

BACKGROUND: Early allograft dysfunction remains a frequently encountered problem in clinical lung transplantation. Lung ischemia-reperfusion injury is associated with increased vascular permeability, which may be due in part to oxygen (O2) free radicals. However, it is not clear whether O2 free radicals are produced during ischemia under storage conditions in clinical lung transplantation. METHODS: Using an isolated ex vivo rabbit lung model, we studied the effects of preservation temperature on pulmonary capillary filtration coefficient (Kf) and lipid peroxidation in rabbit lungs inflated with 100% O2 after preservation with or without the O2 free radical scavenger dimethylthiourea. New Zealand white rabbits weighing 2.7 to 3.1 kg were intubated and ventilated with room air or 100% O2 (tidal volume = 25 mL). After heparinization and sternotomy, the pulmonary artery was flushed with low-potassium-dextran-1% glucose solution (200 mL). The heart-lung block was excised, submerged, and stored for 24 hours at 1 degree or 10 degrees C. After 24-hour preservation, the heart-lung block was suspended from a strain-gauge force transducer and ventilated with room air. The pulmonary artery cannula was connected to a reservoir of hetastarch solution. The lungs were flushed briefly with the hetastarch solution, and the reservoir was raised sequentially at 8-minute intervals to achieve 1.0 to 1.5 mm Hg increments in pulmonary artery pressure. Lung weight gain, airway pressure, pulmonary artery pressure, and left atrial pressure were measured continuously. The slope of steady-state lung weight gain was used to determine Kf (g.min-1.cm H2O-1 x 100 g-1 wet weight). RESULTS: Twenty-four-hour lung preservation at both 1 degree and 10 degrees C increased Kf. A similar increase in Kf was observed in lungs stored at 1 degree C while inflated with 100% O2. However, a significant increase in Kf was observed when lungs inflated with 100% O2 were stored at 10 degrees C. This increase in Kf was ameliorated by dimethylthiourea. Thiobarbituric acid-reactive substance levels were increased in lungs stored at 10 degrees C while inflated with 100% O2. This finding was eliminated by dimethylthiourea. CONCLUSIONS: These results indicate that free radical injury occurs during the ischemic phase when lungs are stored at moderate hypothermia while inflated with 100% O2.

Animals↗
PubMed1995

Serum lipoprotein(a) levels before and after subtotal thyroidectomy in subjects with hyperthyroidism.

Lipoprotein(a) [Lp(a)], a lipoprotein that structurally resembles low-density lipoprotein (LDL), contains apolipoprotein(a) [apo(a)] and apolipoprotein B-100 (apo B). There exists a close inverse correlation between serum concentrations of LDL or apo B and concentrations of thyroid hormone in patients with thyroid disease, probably due to a change in LDL receptor activity. To clarify the relations between thyroid hormone and Lp(a), we measured serum Lp(a) levels in 13 hyperthyroid subjects before treatment (stage H), during the euthyroid stage induced immediately before performing a subtotal thyroidectomy (stage E), and during the hypothyroid stage observed transiently after the operation (stage L). The mean serum concentration of Lp(a) increased significantly (P = .01) from 9.4 mg/dL in stage H to 26.8 in stage L through the level of 15.5 mg/dL in stage E. There was no significant difference between the mean serum concentration of Lp(a) in these patients in stage E and healthy controls (14.2 mg/dL). There was a low but statistically significant negative correlation between the Lp(a) level and the serum free thyroxine (fT4) concentration (r = .31, P < .05). The results suggest that thyroid hormone is a potent modulator of Lp(a) metabolism.

Adult↗
PubMed1995

Neuromagnetic measurements of the human primary auditory response.

The spatio-temporal organization of the human primary auditory response (N19 and P30) was determined by analyzing magnetic fields from the right hemisphere evoked by monaural clicks to the left ear. The magnetic response consisted of peaks corresponding to electrical N19 (N19m) and P30 (P30m) within 40 msec after stimulation. However, the onset of electrical N19 occurred 5-9 msec earlier than that of the magnetic counterpart. Furthermore, the relative amplitude of N19 and P30 (N19/P30) was larger (more than 1) than that (about 0.5) of N19m and P30m (N19m/P30m). The findings suggest an additional contribution from a subcortical source for electrical N19. The estimated equivalent sources for N19m and P30m were localized at the postero-medial part of Heschl's gyrus (the primary auditory cortex). Furthermore, the dipole orientation of N19m was directed postero-ventrally and that of P30m was in the opposite direction, which is compatible with the anatomy of the supratemporal primary auditory cortex. These results resolve a long standing controversy of cortical vs. subcortical structures as the generators of the N19.

Auditory Cortex↗
PubMed1995

Pharmacological effects of dai-saiko-to on lipid biosynthesis in cultured human hepatocyte HepG2 cells.

The pharmacological effects of Dai-saiko-to, a Japanese and Chinese traditional medicinal mixture (Kampohozai), on lipid biosynthesis were investigated in cultured human hepatocyte HepG2 cells. The addition of Dai-saiko-to (0.5 mg/ml), which had no significant effect on cell proliferation, caused a marked decrease in the intracellular triglyceride content with no significant changes in the other lipid fraction. At the same time, the incorporation of 14C-acetate or 3H-glycerol into the triglyceride or diglyceride fractions also decreased significantly. These results suggest that Dai-saiko-to decreases hepatic triglyceride biosynthesis, which might contribute to a reduction in plasma VLDL levels.

Cell Division↗