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Biomedical subjects

Y Takahara

Publications and source records attributed to Y Takahara.

At least 19 recordsLinked to original sources
PubMed2002

[Long-term results of total aortic arch replacement using selective cerebral perfusion].

From June 1994 to July 2001, 92 consecutive patients underwent total aortic arch replacement using hypothermic selective cerebral perfusion. Forty-four patients had nondissecting fusiform or saccular aneurysms (non-ruptured 34, ruptured 10), and 48 patients had dissection (acute 37, chronic 11). Hospital mortality rate was 6.8% in the nondissecting group and 6.3% in the dissecting group. No major operative cerebral complications were observed. There were 9 late deaths in the nondissecting group and 5 late deaths in the dissecting group. The actuarial survival rate was 61.6% after 100 months in the nondissecting group and 82.5% after 86 months in the dissecting group (p = 0.5128). In the postoperative aortic accidents, there were 2 cases of the descending aortic rupture and 2 cases of cholesterol crystal embolization in the nondissecting group and 3 cases of thoracoabdominal grafting, 2 cases of re-operation in the ascending aorta and 1 case of descending aortic rupture in the dissection group. The actuarial freedom from aortic accidents was 88% after 100 months in the nondissecting group and 80% after 86 months in the dissecting group (p = 0.6908). Our surgical outcome of total aortic arch replacement using hypothermic selective cerebral perfusion are satisfactory.

Aged↗
PubMed2001

Combined grafting of thoracic aortic aneurysm and cardiac repair using continuous cold-blood coronary perfusion.

OBJECTIVE: For patients diagnosed with combined thoracic aortic aneurysms and cardiac lesions, we conduct a 1-stage operation for ascending and aortic arch grafting. We studied surgical outcome comparatively with patients undergoing aortic grafting alone. For descending and thoracoabdominal aortic grafting, we choose a 2-stage operation. SUBJECTS AND METHODS: Subjects were 80 patients undergoing ascending and aortic arch aneurysm repair between June 1994 and March 1999. Group 1 consisted of 30 undergoing simultaneous cardiac repair. Concomitant cardiac procedures involved 21 valvular, 5 coronary arterial, and 4 valvular and coronary arterial surgeries. Group 2 consisted of 50 undergoing aortic grafting alone. We used crystalloid cardioplegia and additional antegrade continuous cold-blood coronary perfusion in Group 1, and crystalloid cardioplegia alone in Group 2. RESULTS: Hospital mortality was 10% in Group 1 and 2% in Group 2. Surgery length, cardiopulmonary bypass time, and aortic cross-clamping time in Group 1 were significantly longer than Group 2. Myocardial ischemic time did not differ significantly. Postoperative ICU stay, mechanical ventilation time and catecholamine support time did not differ significantly. Actuarial survival was 66.9 +/- 13.1% at 52 months in Group 1 and 87.2 +/- 4.8% at 57 months in Group 2 (p = 0.2918). CONCLUSION: Simultaneous cardiac repair and ascending and aortic arch aneurysm repair were conducted using continuous cold-blood coronary perfusion. Hospital mortality and mid-term survival did not differ significantly between groups.

Aged↗
PubMed2001

Effect of Sotalol in the prevention of atrial fibrillation following coronary artery bypass grafting.

OBJECTIVE: We assessed the efficacy of postoperatively administered oral Sotalol in preventing the occurrence of postoperative atrial fibrillation. METHODS: Subjects were 80 consecutive patients undergoing coronary artery bypass grafting (CABG) randomized alternately into a Sotalol group (40 patients) administered 80 mg of oral Sotalol daily starting on the postoperative day 1 and continued for 14 days, and a control group (40 patients) matched for age and gender. RESULTS: The incidence of postoperative atrial fibrillation (21 patients) was significantly lower in the Sotalol group (6/40 patients; 15%) than in controls (15/40; 37.5%) (p < 0.05). Significant bradycardia or hypotension, necessitating drug withdrawal, occurred in 3 of 40 (7.5%) patients in the Sotalol group. None in the Sotalol group developed Torsardes de Pointes or sustained ventricular arrhythmias or other severe side effects. The sinus heart rate increased in both groups but less in the Sotalol group. QT, QRS, and QTc durations did not differ between groups. Postoperative hospital stay did not differ between groups. CONCLUSIONS: Oral Sotalol administration of 80 mg daily was associated with a significant decrease in postoperative atrial fibrillation in patients undergoing CABG without appreciable side effects. Sotalol should thus be considered in preventing postoperative atrial fibrillation in patients undergoing CABG in the absence of heart failure and significant left ventricular dysfunction.

Administration, Oral↗
PubMed2001

Acute type A aortic dissection associated with an aortic annular abscess.

We describe a 66-year-old woman who underwent open heart surgery because of congestive heart failure. During operation, we found a Stanford type A dissection and an aortic ring abscess, which had burst into the aortic lumen. No other entries were found. Pathological examination showed excessive neutrophil infiltration in the aortic root. We strongly suspect that the abscess produced the intimal tear to cause the aortic dissection.

Abscess↗
PubMed2001

Comparison of various reproductive status in Sika deer (Cervus nippon) using fecal steroid analysis.

The feasibility of fecal steroid analysis for pregnancy diagnosis and sex determination were tested in sika deer (Cervus nippon). Feces were collected from captive sika deer in June (non-breeding season and late-pregnancy period) and October (breeding season), and also from the rectum of 24 female sika deer (19 pregnant and 5 non-pregnant females) shot as part of programs for population control in February and March (mid-pregnancy period). In mid- and late-pregnancy periods, fecal progesterone concentrations were significantly higher in pregnant female than in male and non-pregnant female deer. In October, fecal testosterone concentrations were higher in adult male deer, and no difference was found between young males and females. These results suggest that fecal steroid analysis would be a useful means for estimating pregnancy status and for detecting adult male among wild deer.

Animals↗
PubMed2001

Patient survival after total knee arthroplasty.

The authors analyzed the 5-year and 9-year survival in 134 of 165 patients who underwent total knee arthroplasties from 1989 to 1996 in our department. Patients were followed until December 31, 1998, or until the time of death. Diagnoses were rheumatoid arthritis in 81 patients (132 knees) and osteoarthritis in 53 patients (79 knees). The survival of the patients was compared to that of the age- and sex-adjusted general population. Kaplan-Meier survival curves were constructed. Twenty-two patients in the study died before the end of the follow-up. The cumulative 5-year patient survival was 88.7%, and 9-year patient survival was 64.4% for total knee arthroplasty patients. The standardized mortality ratio was 0.11 (95% confidence interval: 0.02-0.40) for the patients with osteoarthritis, and 0.81 (95% confidence interval: 0.52-1.25) for the patients with rheumatoid arthritis. The Cox proportional hazards model showed that the factors of male sex and rheumatoid arthritis were related to a higher mortality rate in the total knee arthroplasty group.

Adult↗
PubMed2001

Pulsatile cardiopulmonary bypass failed to prevent neuropsychological dysfunction.

To prevent neurological complications during cardiopulmonary bypass, cerebrovascular screenings by magnetic resonance angiography and computed tomographic scan of the brain were performed preoperatively in patients who had ischemic heart disease and all patients aged 60 years or older. From 1996 to 1999, 173 adult patients (mean age 65.1+/-7.7 y) were evaluated. Forty-one patients were considered to be at high risk from the screening tests and pulsatile cardiopulmonary bypass was applied. The remaining 132 patients were placed in the control group. Postoperative cerebral infarction caused by embolism was encountered in three patients (3/173, 1.7%), two in the high-risk group (2/41, 4.8%) and one in the control group (1/132, 0.8%), but the difference between these incidences was not statistically significant. Cerebral infarctions caused by brain hypoperfusion did not occur in this series. A neuropsychological test (Hasegawa's dementia scale, HDS) was done pre- and postoperatively. No one was diagnosed with dementia preoperatively, whereas 7 patients were diagnosed with dementia postoperatively. Among these 7 patients, 6 patients were in the high-risk group (17.1%, 6/35) and one patient was in the control group (0.9%, 1/113). Under these circumstances, using cerebrovascular screening and pulsatile cardiopulmonary bypass, cerebral infarction due to hypoperfusion did not occur, but cerebral infarction due to embolism was encountered, and neuropsychological dysfunction was not prevented.

Aged↗
PubMed2001

Extended aortic grafting for acute ascending dissection after type B dissection.

A 31-year-old man was diagnosed with acute ascending aortic dissection and massive aortic regurgitation following acute type B dissection during drug treatment. Although the aortic arch was not dissected, we performed aortic replacement from the aortic root to the proximal portion of the descending aorta. The aim of the operation was the prevention of aortic arch dissection, and closure of initial entry of type B dissection.

Adult↗
PubMed2000

Unique substrate specificities of two adjacent glutamine residues in EAQQIVM for transglutaminase: identification and characterization of the reaction products by electrospray ionization tandem mass spectrometry.

Reversed-phase HPLC (RP-HPLC) and electrospray ionization tandem mass spectrometry (ESI-MS/MS) were used to characterize the transglutaminase (TGase)-catalyzed dual modification of a peptide (EAQQIVM, named FibN) with monodansylcadaverine (MDC). The synthesized FibN peptide, which was derived from the N-terminal sequence of fibronectin, was used as the substrate for a guinea pig liver TGase (G-TGase). The time course of incorporation of MDC into FibN, detected by RP-HPLC, indicated two separate fluorescent product peaks. ESI-MS analysis of the isolated fractions indicated that products represented MDC-incorporated FibN molecules in molar ratios of 1:1 ((MDC)-FibN) and 2:1 ((MDC)2-FibN). A sequence analysis of MDC-FibN, using ESI-MS/MS, showed that the first modified residue in FibN was mainly Gln3. The kinetic analysis of MDC incorporation suggested that dual incorporation would occur by mainly one route. A one-dimensional 1H NMR comparison of MDC-FibN and unmodified FibN suggested that the first incorporation of MDC at Gln3 altered the substrate reactivity of the Gln4 residue in FibN for the G-TGase-catalyzed reaction. Thus, a detailed analysis of the peptide products using RP-HPLC and ESI-MS/MS should provide a powerful tool for exploring the mechanism of the substrate requirements of TGases.

Animals↗
PubMed2000

Aortic dissection complicated with aorto-right atrium fistula.

Aorto-right atrium fistula associated with aortic dissection is a very rare complication. Here report a case of successful surgical repair of ascending aortic dissection complicated with aorto-right atrium fistula. A 65-year-old man was presented with sudden chest pain and dyspnea. Fifteen years ago, he had aortic valve replacement. An aortic dissection with fistula to the right atrium was diagnosed by echocardiography and cardiac catheterization. At operation, dense adhesion of the aortic root due to the previous cardiac operation was confirmed, and this was suggested as the cause for this rare complication.

Aged↗
PubMed2000

Strategy for reduction of stroke incidence in coronary bypass patients with cerebral lesions. Early results and mid-term morbidity using pulsatile perfusion.

OBJECTIVES: Cerebral complication is an important factor affecting the outcome after coronary artery bypass surgery under cardiopulmonary bypass. One of the causes for cerebral complication is preoperative cerebrovascular stenotic lesion. Here, we have studied the effect of pulsatile perfusion on the rate of cerebral complication due to a cerebrovascular lesion in patients undergoing coronary arterial bypass graft under cardiopulmonary bypass. METHODS: 261 consecutive elective patients underwent operation using cardiopulmonary bypass for management of the atherosclerotic ascending aorta. Group 1 consisted of 62 patients with a cerebrovascular stenotic lesion (> or = 75%) identified on a magnetic resonance angiogram or multiple cerebral infarction diagnosed using a computer tomogram. Group 2 consisted of 199 patients diagnosed with no significant cerebral lesion. In Group 1, the systolic blood pressure during cardiopulmonary bypass was maintained at a level of 80 mmHg by means of pulsatile flow. In Group 2, non-pulsatile perfusion was used as usual. RESULTS: The overall hospital mortality was 1.5%, and no mortality was caused by a cerebral event. Only one patient in Group 1 suffered from temporary hemiparalysis. A cerebral complication occurred in only 1.6% in Group 1, and 0.4% overall. The actuarial freedom from cerebrovascular accident after 54 months was 84.4% in Group 1, and 96.2% in Group 2 (p = 0.0011). CONCLUSIONS: Management of the atherosclerotic ascending aorta and the use of pulsatile perfusion were helpful in preventing cerebral injury during CABG.

Aged↗
PubMed2000

Clinico-radiological study of total knee arthroplasty after high tibial osteotomy.

The results of total knee arthroplasty (TKA) after high tibial osteotomy (HTO) and problems encountered during the operation were investigated in 23 patients (28 knees). HTO was performed by Coventry's method in 18 knees and by Maquet's method in 10 knees. The mean interval from HTO to TKA was 86 months (range, 3 to 288 months) and the mean follow-up period after TKA was 25 months (range, 6 to 116 months). Radiological evaluation showed that the proximal part of the tibia was shifted and tilted lateroinferiorly after HTO. Thus, a tendency to patella infera was observed. Lateral shift of the proximal part of the tibia was more marked with Maquet's method than with Coventry's method (P < 0.01). Posterior inclination of the tibial articular surface before TKA was smaller in the patients who gained a range of motion of 90 degrees or more after TKA than in those with less than 90 degrees (P < 0.05). In patients with 70 points or more on the three-university score after TKA, there was no change in the joint line level between before and after TKA, while the joint line was significantly lower after TKA in those with less than 70 points (P < 0.01). When TKA is done after HTO, various technical problems may influence the outcome, such as correction of the soft tissue imbalance, in addition to difficulties with patellar eversion and exposure of the proximal part of the tibia. The clinical results of TKA after HTO tend to be slightly inferior to those of primary TKA, probably because of such technical problems.

Aged↗
PubMed2000

Gene transfer into hepatoma cells mediated by galactose-modified alpha-helical peptides.

To develop a receptor-mediated gene delivery system into hepatoma cells using the cationic alpha-helical peptide as the gene carrier molecule, we modified an alpha-helical peptide, which is known to have transfection abilities into cells, with a multi-antennary ligand containing several galactose residues that provide efficient binding to the asialoglycoprotein receptor. The galactose-modified peptides formed complexes with a plasmid DNA and showed gene transfer abilities into HuH-7 cells, a human hepatoma cell line. The transfection efficiency of the peptide was increased by increasing the number of modified galactose residues on the peptide. Furthermore, considerable inhibition of the transfection efficiency by the addition of asialofetuin, which is a ligand for the asialoglycoprotein receptor, was observed in all galactose-modified peptides. Based on this result, we could confirm that the internalization of the galactose-modified peptides occurred by the receptor-mediated endocytosis pathway. In addition, to understand the transport route of the peptide-DNA complex in the cell, the effects on the transfection efficiencies with several endocytosis inhibitors were examined. As a result, it was suggested that the translocation of the peptide-DNA complex from the endocytic compartments to the cytosol mainly occurred during an early endosome step.

Carcinoma, Hepatocellular↗
PubMed2000

Measurement of fatigue in knee flexor and extensor muscles.

In order to examine fatigue of the knee flexor and extensor muscles and to investigate the characteristics of muscular fatigue in different sports, a Cybex machine was used to measure muscle fatigue and recovery during isokinetic knee flexion and extension. Eighteen baseball players, 12 soccer players and 13 marathon runners were studied. Each subject was tested in the sitting position and made to perform 50 consecutive right knee bends and stretches at maximum strength. This was done 3 times with an interval of 10 min between each series. The peak torque to body weight ratio and the fatigue rate were determined in each case. In all subjects, the peak torque to body weight ratio was higher for extensors than flexors. Over the 3 trials, the fatigue rate of extensors showed little change, while that of flexors had a tendency to increase. In each subject, knee extensors showed a high fatigue rate but a quick recovery, while knee flexors showed a low fatigue rate but a slow recovery. As the marathon runners had the smallest fatigue rates for both flexors and extensors, we concluded that marathon runners had more stamina than baseball players and soccer players.

Adolescent↗
PubMed2000

[Aortic valve reconstruction of aortic root repair].

We report the choice of aortic valve reconstruction, surgical results and postoperative results in 22 patients who underwent aortic root replacement between June 1996 and October 1999. We chose the replacement using bio-prosthesis in six patients over 65 years of age and valve preservation or replacement using mechanical prosthesis in sixteen patients under 65 years of age. Ten patients underwent valve replacement using mechanical prosthesis. There was one hospital death and one late death. Six patients underwent valve replacement using bio-prosthesis. There was no hospital death and no late death. Six patients underwent valve preservation. There was one hospital death. There was no event among five patients in the mid-term follow-up, although a longer follow-up must be necessary.

Aged↗
PubMed2000

The effect of carbon dioxide tension on cerebral circulation during hypothermic selective cerebral perfusion.

BACKGROUND: Some reports have observed the response of cerebral blood flow to PaCO2 during hypothermic cardiopulmonary bypass. We studied the effect of PaCO2 on the cerebral circulation during hypothermic selective cerebral perfusion. METHODS: Between June 1992 and January 1998, 35 patients underwent aortic arch grafting using hypothermic selective cerebral perfusion (20 degrees C). In the earlier four patient (Group 1), carbon dioxide gas was not added. In the latter 31 patient (Group 2), carbon dioxide gas was added to the cerebral perfusion. The hemodynamics and rates of change in cerebral oxygen saturation were evaluated. RESULTS: In Group 1, the index of cerebral arterial resistance was 9.2+/-2.2 at the start of selective cerebral perfusion and increased to 15.7+/-0.1 at the re-warming stage (p<0.05), and there was a significant decrease in cerebral oxygen saturation at the re-warming stage (p<0.001). In Group 2, the index of cerebral arterial resistance was 4.7+/-1.7 at the start of selective cerebral perfusion and 4.3+/-1.5 at the re-warming stage, a non-significant change. The change in cerebral oxygen saturation was also nonsignificant between the start of selective cerebral perfusion and the re-warming stage. Among the neurological outcomes, there was only one small cerebral infarction in Group 2; however, no delayed conscious recovery was observed. CONCLUSIONS: The addition of CO2 to cerebral perfusion was a factor in inhibiting the increase in the cerebral vascular resistance at the re-warming stage.

Adult↗
PubMed1999

High yield refolding and purification process for recombinant human interleukin-6 expressed in Escherichia coli.

Recombinant human interleukin-6 (hIL-6), a pleiotropic cytokine containing two intramolecular disulfide bonds, was expressed in Escherichia coli as an insoluble inclusion body, before being refolded and purified in high yield providing sufficient qualities for clinical use. Quantitative reconstitution of the native disulfide bonds of hIL-6 from the fully denatured E. coli extracts could be performed by glutathione-assisted oxidation in a completely denaturating condition (6M guanidinium chloride) at protein concentrations higher than 1 mg/mL, preventing aggregation of reduced hIL-6. Oxidation in 6M guanidinium chloride (GdnHCl) required remarkably low concentrations of glutathione (reduced form, 0.01 mM; oxidized form, 0.002 mM) to be added to the solubilized hIL-6 before the incubation at pH 8.5, and 22 degrees C for 16 h. After completion of refolding by rapid transfer of oxidized hIL-6 into acetate buffer by gel filtration chromatography, residual contaminants including endotoxin and E. coli proteins were efficiently removed by successive steps of chromatography. The amount of dimeric hIL-6s, thought to be purification artifacts, was decreased by optimizing the salt concentrations of the loading materials in the ion-exchange chromatography, and gradually removing organic solvents from the collected fractions of the preparative reverse-phase HPLC. These refolding and purification processes, which give an overall yield as high as 17%, seem to be appropriate for the commercial scale production of hIL-6 for therapeutic use.

Amino Acid Sequence↗