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Biomedical subjects

T Onitsuka

Publications and source records attributed to T Onitsuka.

At least 37 records · Page 2Linked to original sources
PubMed2001

Microchimeric cells from the peripheral blood associated with cardiac grafts are bone marrow derived, long-lived and maintain acquired tolerance to minor histocompatibility antigen H-Y.

BACKGROUND: Although it has been well established that the microchimerism occurs in the peripheral blood of the recipients after various settings in both clinical and experimental organ transplantation, nevertheless, their roles in inducing and maintaining acquired transplantation tolerance are controversial. Furthermore, regarding the cell lineages, kinetics, and functions of the cells that constitute the microchimerism after organ transplantation, solid information is not available. METHODS: Using rat heterotopic heart isografts from bone marrow chimeras between cross-sex and applying polymerase chain reaction with specific primers to rat sex determining region of Y chromosome, a relationship between a state of microchimerism and induction as well as maintenance of acquired tolerance to H-Y antigen were examined. RESULTS: Microchimeric cells of the peripheral blood (MCPB) after cardiac grafting contain bone marrow-derived and radiation-sensitive cells. Furthermore, removal of the primary cardiac grafts revealed that microchimeric cells in the peripheral blood are long-lived cells, i.e., more than 6 months. When the female rats that had contained long-lasting MCPB, were innoculated with syngeneic male dendritic cells, failure to sensitize female toward male specific antigen H-Y was found to occur. CONCLUSIONS: Thus it was suggested that radiation-sensitive, bone marrow derived, long-lived MCPB play a significant role in maintaining acquired transplantation tolerance to minor histocompatibility antigen H-Y.

Animals↗
PubMed2001

Expression of nm23-H1 gene product in esophageal squamous cell carcinoma and its association with vessel invasion and survival.

BACKGROUND: We assessed the nm23-H1 gene product expression and its relationship with lymphatic and blood vessel invasion in patients with esophageal squamous cell carcinoma. METHODS: Formalin-fixed and paraffin-embedded tissue sections from 45 patients who were treated surgically were used in this study. Pathologists graded lymphatic and blood vessel invasion in each of the tissue samples. Expression of nm23-Hl gene product was determined using a specific monoclonal antibody. RESULTS: Expression of nm23-H1 gene product was present in 17 (37.8%) cases. We found an inverse correlation between nm23-H1 gene product expression and lymphatic vessel invasion, whereas no correlation between nm23-H1 gene product expression and blood vessel invasion. Overall survival rate was not different between nm23-H1 gene product positive and negative patients (p = 0.21). However, reduced expression of nm23-H1 gene product was associated with shorter overall survival in patients with involved lymph nodes (p < 0.05), but not in patients without involved lymph nodes (p = 0.87). CONCLUSIONS: In patients with esophageal squamous cell carcinoma, there appears to be an inverse relationship between nm23-H1 gene product expression and lymphatic vessel invasion. Furthermore, nm23-H1 gene product expression might be a prognostic marker in patients with involved lymph nodes. Our data does not demonstrate any correlation between nm23-H1 gene product expression and blood vessel invasion.

Biomarkers, Tumor↗
PubMed2001

Expression of nm23-H1 gene product in mediastinal lymph nodes from lung cancer patients.

OBJECTIVE: Although numerous studies have shown that nm23-H1 gene product expression is inversely related to metastatic potential in some cancers, the expression in lymph nodes has not been studied in detail. An analysis of nm23-H1 gene product expression in mediastinal lymph nodes from lung cancer patients is reported. METHODS: One hundred and thirty-four, randomly selected lymph nodes (63 with positive pathological lymph node status) from 39 surgically treated lung cancer patients were examined. Expression of nm23-H1 gene product was determined using specific monoclonal antibodies. Metastatic cancer cells were highlighted using anti-cytokeratin antibody. RESULTS: Expression of nm23-H1 gene product in patients with less and more than 50% nodes-positive was 12/23 (52.2%) and 15/16 (93.8%) cases, respectively. Immunohistochemical studies with cytokeratin revealed micrometastasis in 6/39 (15.4%) patients and 9/71 (12.7%) nodes previously reported as cancer negative. Expression of nm23-H1 gene product in micrometastasis and metastasis-positive nodes was 5/9 (55.6%) and 55/63 (87.3%), respectively. We also found nm23-H1 gene product expression in germinal center cells. However, we found no relationship between expression of nm23-H1 gene product in germinal center cells and extent of metastasis. CONCLUSIONS: Our study demonstrates a positive relationship between expression of nm23-H1 gene product and extent of metastasis in mediastinal lymph nodes from lung cancer patients. Our data for normal germinal center cells suggests that nm23-H1 gene product expression does not play a specific biological role in suppressing tumor metastasis in lung cancer.

Adenocarcinoma↗
PubMed2001

Association of mast cells with tumor angiogenesis in esophageal squamous cell carcinoma.

The association of mast cells with tumor angiogenesis was investigated in patients with esophageal squamous cell carcinoma. Surgical specimens from 48 patients with esophageal squamous cell carcinoma were studied. Mast cells in tumor sections were stained with Alcian blue and safranin O. The number of mast cells was counted under light microscopy and the average count recorded. To highlight the microvessels, endothelial cells were stained with anti-human factor VIII antibody. Microvessel density was also counted. We found a significant correlation between mast cell count and microvessel density in patients with esophageal squamous cell carcinoma. Double staining of the microvessels revealed highly angiogenic areas densely populated with mast cells. There appears to be a direct correlation between the number of mast cells and tumor angiogenesis in patients with esophageal squamous cell carcinoma.

Adult↗
PubMed2001

The index of motor current amplitude has feasibility in control for continuous flow pumps and evaluation of left ventricular function.

The index of motor current amplitude (ICA) has feasibility in continuous-flow ventricular assist device control. It can demonstrate the safe range of pump speed, which exists between the starting point of total assistance (t-point) and the starting point of sucking (s-point). The objective of this study was to investigate how the ICA characteristic curve changes with each condition of contractility, preload, and afterload changes. We changed preload, afterload, and contractility of closed-mock circulation and plotted the change of the ICA value against pump speed. Then the shift of ICA characteristic curve against the change of each condition was considered. When preload increased, ICA characteristic curves showed the expansion of a safe range. When afterload increased, ICA characteristic curves were shifted to the high rotation side, slightly narrowing a safe range. When contractility increased, ICA characteristic curves showed the shift of a convex above to narrowing of a safe range. As these shift patterns were observed even when the driving conditions of a circuit changed, reproducibility was checked. Understanding the feature of a shift pattern of ICA characteristic curves correctly, a possibility that change of the heart function could be predicted by change of ICA value and a possibility for a flexible control method based on ICA, according to hemodynamic state, were suggested.

Blood Flow Velocity↗
PubMed2001

[Blue toe syndrome after coronary artery bypass grafting].

We report three cases of blue toe syndrome (BTS) after coronary artery bypass grafting (CABG). All patients were cyanotic and exhibited painful toes two to four weeks after CABG. They were treated with antiplatelet and anticoagulant agents, and one patient underwent replacement of the abdominal aorta. Thus, BTS may occur after CABG with coronary angiography, extra-corporeal circulation or intraaortic balloon pumping. For the treatment of BTS, surgery remains the most effective option.

Aged↗
PubMed2001

[Anti-bleeding effect of nafamostat mesilate for the surgery of thoracic ascending aorta].

UNLABELLED: During extracorporeal cardiopulmonary bypass (ECB), the activated coagulation and fibrinogenolysis system causes bleeding and postoperative multiple organ failures. We studied the effect of an anti-bleeding agent, nafamostat mesilate (NM) during the surgery of thoracic ascending aorta to decrease a side effect of bleeding. From March 1980 to January 1998, for thoracic ascending aorta operations in our department (true aneurysm, 16-, psudoaneurysm, 2-, and dissection, 11 cases, in 29 cases, respectively), age from 16 to 79 (mean 62.9 +/- 9.5 year of age), we classified the objects in two groups, NM group (intraoperative infusion with NM of 60 mg/hr and with heparin 300 IU/kg) and C group (only with heparin treated, 500 IU/kg). We investigated the preoperative factors (age and aneurysmal diameter), the intraoperative factors (ACT, hematcrit, platelet, aorta clamping time, operative time, ECB time, bleeding volume, and blood transfusion), and the postoperative factors (bleeding and blood transfusion) after the administration of NM. RESULTS: There was no significance for the protection effect of NM infusion on the preoperative and the postoperative factors. However, intraoperative bleeding and blood transfusion volume in NM group were significantly lesser than those in group C. CONCLUSIONS: It might be useful for NM infusion during the surgery of thoracic ascending aorta due to the decrease of volume of intraoperative bleeding and blood transfusion amount with the remarkable anti-bleeding effect.

Adolescent↗
PubMed2000

Surgical management of ductus arteriosus aneurysm in adults.

Aneurysm of the ductus arteriosus is rare, especially in adults, and preoperative diagnosis is very difficult, requiring intraoperative diagnosis. A 71-year-old man was preoperatively diagnosed with ductus arteriosus aneurysm by computed tomographic scanning, magnetic resonance imaging, and aortography, which demonstrated a saccular aneurysm of the distal aortic arch. Under partial extracorporeal circulation, the aneurysm was replaced by an artificial vascular graft. The location and morphology of the aneurysm confirmed the preoperative diagnosis. The postoperative course was uneventful. Surgery for this condition is safe and is recommended the same as for common thoracic aortic aneurysm.

Aged↗
PubMed2000

A rapidly growing benign intrathoracic neurofibroma after lung lobectomy.

A 67-year-old male underwent a right upper lung lobectomy for lung cancer in January 1993. Follow-up chest X-rays revealed a progressive and rapidly growing intrathoracic mass in the right thorax. The mass, however, did not resemble a tumor recurrence, and the patient complained only of shortness of breath. Computerized tomography and magnetic resonance imaging confirmed the presence of the intrathoracic mass and its associated compression of the residual lung. A right thoracotomy was performed in January 1998, and a mass found arising from the sympathetic nerve trunk was resected. Microscopic examination revealed stellate or spindle-shaped cells in myxoid stroma with sparsely distributed collagen fibers. Immunohistochemically, the cells were positive for neuron-specific enolase, and the tumor was identified as neurofibroma. The patient did not suffer from von Recklinghausen's disease, and there was no family history of the disease. After resection of the neurofibroma, the compressed lung was able to re-expand, and the patient's shortness of breath disappeared. At one year postoperative, the patient remains well, and there is no evidence of recurrence.

Aged↗
PubMed2000

Successful treatment of a bronchial inflammatory pseudotumor by bronchoplasty in an 8-year-old boy: report of a case.

We report herein the rare case of an 8-year-old boy in whom an inflammatory pseudotumor of the upper lobe bronchus of the right lung was successfully treated by bronchoplasty. A bronchoscopy was initially performed to investigate the cause of pulmonary atelectasis in the right upper lobe, which revealed a tumor in the right main bronchus. Thus, a thoracotomy followed by bronchotomy of the right main bronchus was carried out. The tumor was seen to have polypoid protrusion into the right main bronchus at the orifice of the upper lobe. A bronchoplasty with a wedge resection of the right main bronchus and right upper lobectomy was carried out, effectively preserving right pulmonary function. Histological examination confirmed the diagnosis of an inflammatory pseudotumor. The patient had an uneventful postoperative course and has been free of recurrence for 3 years since his operation.

Biopsy, Needle↗
PubMed2000

Effect of mast cells on tumor angiogenesis in lung cancer.

BACKGROUND: We conducted a retrospective study to clarify the effect of mast cells on tumor angiogenesis in lung cancer patients. METHODS: Formalin-fixed and paraffin-embedded tumor sections were used in this study. Parenchymal mast cells were stained with Alcian blue and safranin O. The number of mast cells per ten fields at a magnification of 200x was counted under light microscopy, and the average count was determined. To highlight the microvessels, endothelial cells were stained with anti-human factor VIII antibody. After the microvessel count was determined, the microvessels were further stained with Alcian blue and safranin O to show areas of mast cell infiltration. Expression of vascular endothelial growth factor was assessed using a polyclonal antibody. RESULTS: We found a significant correlation between mast cell count and microvessel density. This correlation was also observed in patients with adenocarcinoma (p < 0.001) as well as in patients with squamous cell carcinoma (p < 0.01). Double staining of the microvessels showed highly angiogenic areas densely populated with mast cells. Although we detected a slight trend toward a correlation between vascular endothelial growth factor expression and microvessel density, it was not statistically significant. We found no association between vascular endothelial growth factor expression and mast cell count. CONCLUSIONS: There appears to be a direct correlation between the number of mast cells and tumor angiogenesis in patients with lung cancer, and this relationship appears to be independent of vascular endothelial growth factor expression.

Adult↗
PubMed2000

Nafamostat mesilate treatment during open heart operation in immune thrombocytopenic purpura.

A 58-year old woman with idiopathic thrombocytopenic purpura underwent mitral and aortic valve replacements and tricuspid annuloplasty. Preoperative therapeutic interventions including prednisone and immunoglobulin were successful in elevating the platelet count to 93,000/ mm2. Furthermore, we used nafamostat mesilate for coagulopathy prophylaxis during cardiopulmonary bypass. Postoperative bleeding was average and clinical course was uneventful. The perioperative management for patients with idiopathic thrombocytopenic purpura requiring cardiac operation is reviewed.

Anticoagulants↗
PubMed2000

The effect of interstimulus intervals and between-block rests on the auditory evoked potential and magnetic field: is the auditory P50 in humans an overlapping potential?

OBJECTIVE: The human auditory P50 may consist of overlapping potentials. To test this hypothesis, we manipulated interstimulus intervals (ISIs) and between-block rests, and recorded the P50, P50m, N100 and the N100m simultaneously. METHODS: Subjects were 12 right-handed healthy adults. Four conditions included: (1) 1.5 s/rest, (2) 1.5 s/successive, (3) 0.5 s/rest, and (4) 0.5 s/successive. Auditory stimuli were presented a total of 880 times for each condition. Auditory evoked potentials and magnetic fields were recorded. We examined the P50, N100, P50m, N100m and dipoles of the P50m and the N100m. RESULTS: There was no significant effect of the ISI on the P50 amplitudes, but the P50m amplitudes in the 0.5 s ISI conditions were significantly smaller than those in the 1.5 s ISI conditions. The N100 and the N100m amplitudes in the 0.5 s ISI conditions were significantly smaller than those in the 1.5 s ISI conditions. The N100 and the N100m amplitudes in the resting conditions were significantly larger than those in the successive conditions. The P50m dipoles were slightly deeper and more anterior than those of the N100m in primary auditory cortex. CONCLUSIONS: Central structures other than supratemporal cortex contribute to the P50 and that the P50 in humans represents overlapping potentials.

Acoustic Stimulation↗
PubMed2000

Auditory P50 obtained with a repetitive stimulus paradigm shows suppression to high-intensity tones.

We manipulated stimulus intensity and number of frequency bands in auditory stimuli in order to investigate the nature of P50 in human auditory evoked potentials. Pure-tone and mixed-tone conditions were examined. For each condition, four stimulus intensities were used: 55, 70, 85 and 100 dB sound pressure level (SPL). The P50s were obtained at Cz using a repetitive stimulus paradigm. P50 amplitudes increased as stimulus intensities increased up to 85 dB; with 100 dB stimulation amplitudes decreased. The number of frequency bands in the stimulus did not affect P50 amplitude. Considered in terms of P50 suppression under a conditioning/testing paradigm, the results suggest that the P50 wave reflects activity of the sensory gating mechanism in humans.

Adult↗
PubMed2000

Potentialities and problems of a novel bilateral ventricular assist system without thoracotomy.

Mechanical cardiac assistance can be critical in saving the lives of patients with acute cardiac failure. However, currently used methods of ventricular assistance require advanced technical knowledge and equipment, and only small numbers of patients can be provided with them. Our aim was to develop new cannulas to construct a less invasive biventricular assist system that would permit easy application without thoracotomy. We prepared 2 centrifugal pumps and 4 uniquely shaped cannulas and conducted experiments to investigate the potential and problems of the system. In the first experiment, the system was attached to 6 dogs with ventricular fibrillation to confirm whether our system could maintain cardiac output. In the second experiment, the system was installed for 3 days in 3 goats, and changes in aminotransferases, BUN, creatinine, and plasma free hemoglobin levels were examined. In Experiment 1, it was demonstrated that the system was able to maintain circulation in dogs. In Experiment 2, although the flow rate of the pumps was maintained over 3 days, increased hemolysis and deteriorating renal function were observed. Although these problems need to be solved, the system was still helpful in the management of acute biventricular failure for short periods and may be clinically useful in the near future.

Acute Disease↗
PubMed2000

Control strategy for biventricular assistance with mixed-flow pumps.

A left ventricular assist device (LVAD) is an effective method to rescue severe heart failure. Although some require a biventricular assist, the control method for the biventricular assist device (BVAD) with a rotary pump is rarely shown. The objective of this study was to investigate the strategy for controlling BVAD with rotary pumps by in vivo studies. Using 5 piglets, we set a BVAD through a left thoracotomy and made global ischemia for 30 min by clamping the base of the ascending aorta. After unclamping, the analysis of pumping performance acted for 6 h reperfusion. We set the target flow of the LVAD and set the right ventricular assist device (RVAD) speed limit as less than when the atrial collapse occurs. To detect the ventricular collapse without any specific sensor, we calculated the index of current amplitude from motor current waveform and simultaneous mean current value. In all cases, over 6 h of observation was performed, and the RVAD was weaned almost automatically.

Analysis of Variance↗
PubMed2000

The steady-state kinetics of the enzyme reaction tested by site-directed mutagenesis of hydrophobic residues (Val, Leu, and Cys) in the C-terminal alpha-helix of human adenylate kinase.

To elucidate whether the C-terminal region in human adenylate kinase participates in the interaction with the substrate (MgATP(2-) and/or AMP(2-)), hydrophobic residues (Val182, Val186, Cys187, Leu190, and Leu193) were substituted by site-directed mutagenesis and the steady-state kinetics of fifteen mutants were analyzed. A change in the hydrophobic residues in the C-terminal domain affects the affinity for substrates (K(m)), that is, not only for MgATP(2-) but also for AMP(2-), and the catalytic efficiency (k(cat)). The results obtained have led to the following conclusions: (i) Val182 may interact with both MgATP(2-) and AMP(2-) substrates, but to a greater extent with MgATP(2-), and play a role in catalysis. (ii) Val186 appears to play a functional role in catalysis by interacting with both MgATP(2-) and AMP(2-) to nearly the same extent. (iii) Cys187 appears to play a functional role in catalysis. (iv) Leu190 appears to interact with both MgATP(2-) and AMP(2-) substrates but to a greater extent with AMP(2-). (v) Leu193 appears to interact with both MgATP(2-) and AMP(2-) but to a greater extent with AMP(2-). The activity of all mutants decreased due to the change in substrate-affinity. The closer the residue is located to the C-terminal end, the more its mutation affects not only MgATP(2-) but also AMP(2-) substrate binding. The hydrophobic alterations disrupt hydrophobic interactions with substrates and that might destabilize the conformation of the active site. The more C-terminal part of the alpha-helix appears to interact with AMP, as if it has swung out and rotated to cover the adenine moieties. The C-terminal alpha-helix of human adenylate kinase appears to be essential for the interaction with adenine substrates by swinging out during catalysis.

Adenosine Monophosphate↗