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Biomedical subjects

K Yasuda

Publications and source records attributed to K Yasuda.

At least 217 records · Page 12Linked to original sources
PubMed2000

An increase in macrophage migration inhibitory factor release in patients with cardiopulmonary bypass surgery.

To determine the macrophage migration inhibitory factor (MIF) responses to cardiopulmonary bypass (CPB) surgery as well as to investigate their roles in predicting patient outcome, a prospective, observational, pilot study was performed. Thirty patients undergoing cardiovascular surgery with CPB received 10mg/kg betamethasone immediately before the CPB. Ten normal healthy volunteers served as control subjects. Blood samples were serially obtained for 24h and assayed for MIF, cortisol, and tumor necrosis factor alpha (TNF-alpha). TNF-alpha release could not be detected during the study period. Compared with both the control and baseline values, the MIF and cortisol levels were elevated before CPB and peaked at the end of CPB (57.5 +/- 4.8 ng/ml, P < 0.0001), and at the end of the surgery (507.7 +/- 44.1 nmol/l, P < 0.0001), respectively. Peak MIF levels correlated with aortic cross-clamp time (r2 = 0.183, P = 0.0182, n = 30), but did not show a significant correlation with peak cortisol levels. The levels of MIF tended to be 40%-50% higher during CPB in patients with longer intensive care unit (ICU) stays and in those with organ dysfunction than in those with short ICU stays and no organ dysfunction. All patients were discharged from the ICU. In conclusion, our findings demonstrate that MIF production occurs in patients with CPB surgery. When high-dose steroids are administered, high MIF levels were found to only slightly affect the patient morbidity and outcome after CPB surgery.

Cardiopulmonary Bypass↗
PubMed2000

Recurrence of giant adrenocortical carcinoma in the contralateral adrenal gland 6 years after surgery: report of a case.

We report herein the case of a patient in whom a giant adrenocortical carcinoma was found to have recurred in the contralateral adrenal gland and intrapelvic cavity 6 years after his initial operation. A 52-year-old man had consulted our hospital complaining of right upper abdominal pain and weight loss, and was subsequently diagnosed as having a giant adrenal tumor by computed tomography scans and echography. A laparotomy was performed and the tumor, located in the right retroperitoneal cavity and infiltrating the liver and right kidney, was surgically removed. The lesion, 29 x 19 x 10 cm in size and 4700 g in weight, was histopathologically diagnosed as an adrenocortical carcinoma. Adjuvant chemotherapy with mitotane was given for 3 months and his postoperative course was uneventful until a recurrence in the contralateral adrenal gland and peritoneal cavity was found 6 years later. The second resection was successful, and he is currently alive with no further sign of recurrence 8 years after his first operation. We report this unusual case as it provides much useful information on the biological features of adrenocortical carcinomas and the state of tumor dormancy.

Adrenal Cortex Neoplasms↗
PubMed2000

Enhanced graft healing of high-porosity expanded polytetrafluoroethylene grafts by covalent bonding of fibronectin.

The effect of covalent bonding of fibronectin on the patency and graft healing of high-porosity expanded polytetrafluoroethylene (ePTFE) grafts was evaluated. Bilateral carotid grafting was performed in ten mongrel dogs using high-porosity (60 microm) ePTFE grafts, 4 cm in length and 4 mm in internal diameter, that either had been pretreated by the covalent bonding of fibronectin (fibronectin grafts) or were untreated (control grafts). The grafts were harvested 4 to 6 weeks after surgery and subjected to macroscopic and light-microscopic observations. There was no significant difference in patency between the fibronectin grafts and the control grafts with rates of 80% and 70%, respectively. The thrombus-free area score was significantly greater in the fibronectin grafts than in the control grafts, at 86.9% vs 34.0%. Furthermore, the pseudointima was better replaced by fibrous tissue in the fibronectin grafts than in the control grafts, being lined with a layer of endothelial-like cells. More transmural tissue ingrowth was evident in the fibronectin grafts than in the control grafts. The covalent bonding of fibronectin improves graft healing by stimulating transmural tissue ingrowth in high-porosity ePTFE grafts.

Animals↗
PubMed2000

Distribution of arterial involvement in thromboangiitis obliterans (Buerger's disease): results of a study conducted by the Intractable Vasculitis Syndromes Research Group in Japan.

The clinical profile of thromboangiitis obliterans (TAO) has been changing. The purpose of this study was to clarify the distribution of arterial involvement in this disease, based on a nationwide survey carried out in 1993. A total of 825 TAO patients with complete records were analyzed. There were 749 men and 76 women, with a mean age of 50.8 +/- 0.4 years. The survey assessed clinical manifestations categorized by Fontaine's classification, distribution of the lesions, associated diseases, responses to treatment, and outcome. This study focused on the distribution of arterial involvement. There were 42 patients (5.1%) with upper-extremity arterial involvement only, 616 (74.7%) with lower-extremity involvement only, and 167 (20.2%) with both. The most frequently affected arteries were the anterior (41.4%) or posterior (40.4%) tibial arteries in the lower extremities, and the ulnar artery (11.5%) in the upper extremities. There were no significant differences in the distribution of arterial involvement between men and women or between the right and left sides. In conclusion, approximately 25% of the patients had upper-extremity involvement. The anterior or posterior tibial arteries were most commonly affected. There was no significant difference in the distribution of arterial involvement between male and female patients.

Adolescent↗
PubMed2000

High-porosity expanded polytetrafluoroethylene grafts for thoracic vena cava replacement with or without an omentum wrap.

We previously reported that, in a short-term thoracic inferior vena cava (IVC) replacement, a high-porosity expanded polytetrafluoroethylene (ePTFE) graft (fibril length 60 microm) performed well without altering the short-term patency, and that the healing of the high-porosity ePTFE graft was accelerated by an omentum wrap. The purpose of this study was to examine the long-term performance of the high-porosity ePTFE graft with or without an omentum wrap. Eighteen grafts were placed as a thoracic IVC replacement in dogs. Nine of the grafts were wrapped in an omental pedicle flap while the other 9 were not. At 1 month and 6 months, the grafts were harvested and examined for a pathological analysis. During the observation period, one dog died of a viral infection, while the other 17 dogs survived. At 1 month and 6 months, the patency rates of the 17 grafts were 100% regardless of the presence or absence of an omentum wrap. The healing of the grafts without omentum wrap was incomplete 6 months after implantation; granulation tissue was present in the center of the pseudointima. The grafts healed completely by the addition of an omentum wrap. Our data suggest that, with an omentum wrap, the high-porosity ePTFE graft is fully expected to show a good long-term function.

Animals↗
PubMed2000

Combining the selective arterial calcium injection test and intraoperative blood glucose monitoring for multiple insulinomas: report of two cases.

To date, no precise methods of preoperatively localizing multiple insulinomas or intraoperatively confirming their complete removal have been established. We describe herein the effectiveness of combining the selective arterial calcium injection (SACI) test to locate tumors preoperatively, with intraoperative continuous blood glucose monitoring (IOBGM) to confirm their complete removal. During the 8-year period from 1990 to 1997, we experienced two patients with multiple insulinomas. The first patient required resection of a residual tumor in the remnant pancreas for persistent hyperinsulinemia after a distal pancreatectomy performed under conventional diagnostic procedures. In the second patient, a SACI test was performed in addition to other diagnostic imaging procedures, and while computed tomography scan, endoscopic ultrasonography, and arteriography demonstrated multiple tumors in the body and tail of pancreas, the SACI test suggested that there were also tumors in the head of pancreas. Intraoperative ultrasonography showed a tumor measuring 5 mm in diameter on the surface of the head of the pancreas, apart from the multiple tumors in the body and tail of the pancreas. Complete removal of all tumors was assessed by the hyperglycemic rebound after resection of the tumors, determined by IOBGM. Based upon our experience, we believe that the SACI test and IOBGM are helpful for establishing precise localization and achieving complete removal of multiple insulinomas.

Blood Glucose↗
PubMed2000

Biomechanical comparisons of anterior cruciate ligament: reconstruction procedures with flexor tendon graft.

An experimental study was conducted to compare the biomechanical characteristics of six currently available anterior cruciate ligament (ACL) reconstruction procedures with flexor digitorum profundus tendons. Forty porcine knees were divided into eight groups, of 5 knees each. In groups A, B, C, and D, the flexor tendon graft was fixed with sutures and an Endobutton, with 20-mm-wide polyester tapes and staples, with 10-mm-wide polyester tapes and an Endobutton, and with bone plugs and interference screws, respectively. In group E, the graft was fixed using a combined procedure of those in groups B and D. In group F, the graft was directly fixed with interference screws. In groups G and H, the bone-patellar tendon-bone graft was fixed with interference screws, and sutures, respectively. Each femur-graft-tibia complex specimen was tested with a tensile tester by anteriorly translating the tibia until failure. This study demonstrated that the biomechanical properties of the femur-graft-tibia complex reconstructed with the flexor tendon graft were significantly affected by synthetic fixation devices. Regarding the average maximal load of the groups with the flexor tendon graft, group B had the highest (893 N) and group C had the second highest (770 N). Groups E and A were in the third rank. Group F had the second lowest (312 N), and Group D had the lowest (230 N). The maximal load of group B was significantly greater (P < 0.01) than that of group G (656 N) with the bone-patellar tendon-bone grafts. As to clinical relevance, this study indicated that the flexor tendon graft can be an alternative substitute for the bone-patellar tendon-bone graft for ACL reconstruction, if we understand the biomechanical characteristics of each reconstruction procedure.

Animals↗
PubMed2000

Non-homologous recombination between Alu and LINE-1 repeats caused a 430-kb deletion in the dystrophin gene: a novel source of genomic instability.

Although large deletions in the dystrophin gene have been identified in more than two-thirds of Duchenne and Becker muscular dystrophy patients, the molecular mechanisms that lead to the generation of these deletions are largely unknown. Here, Alu and LINE-1 (L1) repetitive elements were shown to be present at one or other of the two ends, respectively, of a 430-kb deletion in the dystrophin gene. The breakpoint of the deletion, which stretches from exons 2 to 7, was defined more precisely by polymerase chain reaction (PCR) walking on introns 1 and 7. Finally, the region containing the breakpoint was amplified as a fragment of more than 10kb. Sequencing of the deletion endpoint revealed the presence of an Alu sequence in intron 1, 25 kb downstream from the 3' end of exon 1 that was joined directly to an L1 sequence in intron 7, 4.5kb downstream from the 3' end of exon 7. The deletion was calculated to be 430kb. To our knowledge, this is a novel recombination event joining non-homologous Alu and L1 repeats, and is the largest known intrachromosomal deletion that is thought to involve repetitive genetic elements. Sequence characteristics around the breakpoint are discussed.

Alu Elements↗
PubMed2000

Midline exposure of the thoracoabdominal aorta.

Extended aortic replacement from the aortic arch to the descending thoracic or thoracoabdominal aorta has been performed through a left thoracotomy or a thoracoabdominal incision combined with or without a median sternotomy. However, a left thoracotomy incision may be unfavorable when dense adhesion of the lung is anticipated. We report a redo patient who underwent simultaneous replacements of the aortic arch and the thoracoabdominal aorta through a midline incision without entering the left pleural cavity.

Aged↗
PubMed2000

Lazaroid reduces production of IL-8 and IL-1 receptor antagonist in ischemic spinal cord injury.

BACKGROUND: 21-aminosteroids (lazaroids) have demonstrated the protective effect against cerebral ischemic injury through the inhibition of lipid peroxidation. We examined whether lazaroids affected the production of proinflammatory and antiinflammatory cytokines in ischemic spinal cord injury model. MATERIALS: Anesthetized New Zealand white rabbits underwent a 20-minute infrarenal aortic cross-clamping (AXC) with pretreatment of either an intravenous 3 mg/kg lazaroid U74389G (group L; n = 10) or the same volume saline (group P; n = 10). Sham operation group (group S; n = 6) underwent only exposure of the aorta. Plasma concentrations of interleukin (IL)-8, -1beta, -1 receptor antagonist (IL-1ra) and tumor necrosis factor (TNF)-alpha were measured at four time points. Functional assessment with Tarlov score at 24 and 48 hours after pretreatment, pathologic assessment of the spinal cord, and measurements of cytokine levels in the spinal cord were performed. RESULTS: The maximum elevation of plasma IL-8 and -1ra levels occurred at 1 hour after declamping in four measurement points. Plasma IL-8 and -1ra levels in group L were significantly lower than those in group P (*p < 0.05). Plasma TNFalpha peaked at 5 minutes after declamping, but decreased afterwards. Plasma TNFalpha levels were not different among three groups. Spinal IL-8 levels in group L (0.98 +/- 0.34 ng/g tissue) were lower than those in group P (7.26 +/- 2.26 ng/g tissue)(*p < 0.05). Spinal IL-1ra and TNFalpha were not significantly different. Tarlov score and pathologic assessment were better in group L. CONCLUSIONS: Lazaroid U-74389G reduced the production of systemic IL-8 and -1ra and spinal IL-8 when AXC caused spinal cord injury. These results indicate that lazaroids may attenuate ischemic endothelial cell injury or activation of leukocytes.

Animals↗
PubMed2000

The effects of stress enhancement on the extracellular matrix and fibroblasts in the patellar tendon.

The purpose of the present study is to determine the effect of the stress enhancement and intrinsic fibroblasts on the extracellular matrix of the patellar tendon. Thirty-two female Japanese White rabbits were divided into four groups. In Group 1, the patellar tendon underwent the in situ freeze-thaw treatment to kill intrinsic fibroblasts of the patellar tendon and the patellar tendon underwent the wrapping treatment with nylon membrane filters to inhibit extrinsic cell infiltration. In Group 2, the medial and the lateral portions of the frozen-thawed patellar tendon were resected to enhance the stress, and then the central two-thirds of the patellar tendon underwent the wrapping treatment. In Group 3, the patellar tendon without the freeze/thaw treatment underwent the wrapping treatment. In Group 4, the patellar tendon was narrowed and wrapped in the same manner. All rabbits were killed 6 weeks after surgery. While the elastic modulus and the tensile strength of the patellar tendon in Group 2 were significantly less than those in Group 1, we could not find any significant differences in these parameters between Groups 3 and 4. Histologically, while no fibroblasts were observed in Groups 1 and 2, fibroblasts were found in Groups 3 and 4. This study revealed that stress enhancement decreases the elastic modulus and the tensile strength of the extracellular matrix of the patellar tendon and that intrinsic fibroblasts prevent the detrimental effect of stress enhancement on mechanical properties of the patellar tendon.

Analysis of Variance↗
PubMed2000

Randomized, double-blind study of electrical stimulation for urinary incontinence due to detrusor overactivity.

OBJECTIVES: To evaluate the usefulness of electrical stimulation for urinary incontinence due to detrusor overactivity in a randomized, double-blind manner. METHODS: Sixty-eight patients (29 men, 39 women, 70.0 +/- 11.2 years) were studied. Detrusor overactivity was urodynamically defined as involuntary detrusor contractions of more than 15 cm H(2)O during the filling phase. Ten-hertz square waves of 1-ms pulse duration were used. A vaginal electrode was used in the women and an anal or surface electrode in the men. The stimulation was given for 15 minutes twice daily for 4 weeks. The efficacy was evaluated on the basis of a frequency/volume chart and urodynamic study before and after treatment. RESULTS: Thirty-two patients in the active group and 28 in the sham group completed the study. The patient impressions were very good or good in 59% and 39% of the active and the sham group, respectively (P = 0.0354). On the cystometrogram, the bladder capacity at the first desire to void and the maximum desire to void increased significantly (P = 0.0104 and P = 0.0046, respectively) in the active group, but not in the sham group. Seven patients in the active group and 1 patient in the sham group were cured (P = 0.0324); 26 patients (81.3%) in the active group and 9 (32.1%) in the sham group improved (P = 0.0001). Of 17 patients in the active group, 13 remained cured or improved for an average of 8.4 months after completion of the 4-week treatment; in the sham group, 3 of 6 patients were cured or improved for an average of 4.7 months after completion of the 4-week treatment. CONCLUSIONS: Electrical stimulation was useful in treating urinary incontinence due to detrusor overactivity.

Adult↗
PubMed2000

Interference screw fixation of doubled flexor tendon graft in anterior cruciate ligament reconstruction - biomechanical evaluation with cyclic elongation.

OBJECTIVE: To biomechanically evaluate interference screw fixation of the doubled flexor tendon graft in anterior cruciate ligament reconstruction using cyclic elongation. DESIGN: Biomechanical properties of the interference screw fixation of the flexor tendons were compared with those of three standard fixation techniques which had been commonly performed in anterior cruciate ligament reconstruction. BACKGROUND: The interference screw fixation of the flexor tendon graft has attracted notice because of various possible advantages. METHODS: Forty fresh frozen porcine hind limbs were divided into four groups of ten knees each. Anterior cruciate ligament reconstruction was carried out in each group using one of four different procedures. For each group, five femur-graft-tibia complexes underwent submaximal cyclic elongation of 5000 cycles after initial tension of 80 N was applied. Then, tensile testing was performed in the same manner for the complex with a tensile tester. The remaining five complexes were examined in the same tensile test without applying any cyclic elongation. RESULTS: The initial tension was more rapidly relaxed by cyclic elongation in the flexor tendon graft fixed with interference screws than in the bone-patellar tendon-bone graft fixed with two standard techniques. After cyclic elongation, while the ultimate failure load of the former was significantly lower than the latter, the linear stiffness of the former was significantly higher than the flexor tendon graft fixed with sutures. CONCLUSION: The present study has clarified that the advantage of the interference fixation for the doubled flexor tendon graft is the high linear stiffness of the FGT complex, and the disadvantage of this screw is the low ultimate failure load of the FGT complex. RELEVANCE: The present study has suggested that vigorous activities should not be permitted for the patients in the early period after anterior cruciate ligament reconstruction using this fixation technique, because of its low ultimate failure load.

Animals↗
PubMed2000

Reduction of polyethylene wear by concave dimples on the frictional surface in artificial hip joints.

For the purpose of reduction of polyethylene wear generated in artificial hip joints, concave dimples were formed on the surface of the metal femoral head by electrical discharge etching with the constant diameter of 0.5 mm, pitch of 1.2 mm, and depth of 0.1 mm. Using a hip joint simulator, the total amount of polyethylene wear was 7.2 mg in the concave-patterned condition and 23.1 mg in the nonpatterned condition. The reasons for the reduction of polyethylene wear by the concave pattern may be i) a reduction of abrasive wear by providing escape dimples for wear particles and ii) an improvement in the lubricity on the frictional surface by the supply of lubricant that is stored in dimples.

Friction↗
PubMed2000

Effect of pertussis toxin on insulin-induced signal transduction in rat adipocytes and soleus muscles.

It has been reported that pertussis toxin (PTX) suppresses the function of trimeric guanine nucleotide binding protein (G-protein). We examined the effect of PTX on insulin-induced glucose uptake, diacylglycerol (DG)-protein kinase C (PKC) signalling, phosphatidylinositol (PI) 3-kinase and PKC zeta activation and insulin-induced tyrosine phosphorylation of Gialpha to clarify the role of G-protein for insulin-mediated signal transduction mechanism in rat adipocytes and soleus muscles. Isolated adipocytes and soleus muscles were preincubated with 0.01 approximately 1 ng/ml PTX for 2 hours, followed by stimulation with 10-100 nM insulin or 1 microM tetradecanoyl phorbol-13-acetate (TPA). Pretreatment with PTX resulted in dose-responsive decreases in insulin-stimulated [3H]2-deoxyglucose (DOG) uptake, and unchanged TPA-stimulated [3H]2-DOG uptake, without affecting basal [3H]2-DOG uptake. In adipocytes, insulin-induced DG-PKC signalling, PI 3-kinase activation and PKC zeta translocation from cytosol to the membrane were suppressed when treated with PTX, despite no changes in [125I]insulin-specific binding and insulin receptor tyrosine kinase activity. Moreover, to elucidate insulin-stimulated tyrosine phosphorylation of 40 kDa alpha-subunit of G-protein (Gialpha-2), adipocytes were stimulated with 10 nM insulin for 10 minutes, homogenized, immunoprecipitated with anti-phosphotyrosine antibody, and immunoblotted with anti-Gialpha-2 antibody. Insulin-induced tyrosine phosphorylation of Gialpha-2 was found by immunoblot analysis with anti-Gialpha-2 antibody. These results suggest that G-protein regulates DG-PKC signalling by binding of Gialpha-2 with GTP and PI 3-kinase-PKC zeta signalling by releasing of Gbetagamma via dissociation of trimeric G-protein after insulin receptor tyrosine phosphorylation in insulin-sensitive tissues.

Adipocytes↗