Biomedical subjects

M Usui

Publications and source records attributed to M Usui.

At least 163 records · Page 9Linked to original sources

PubMed1997

Long-term results of Charnley low-friction arthroplasty for coxarthrosis with congenital hip dysplasia. 15 year follow-up study.

We studied more than fifteen-years' follow-up results of cases treated with low-friction arthroplasty (LFA) for coxarthrosis with congenital hip dysplasia. Thirty-four LFAs in 32 patients (2 males and 30 females) were followed up for an average of 18.8 years (range: 15 to 23.3 years). The mean age at surgery was 53 years (range: 36 to 67 years). In three patients, 4 hips needed revision surgery due to loosening of the prostheses. At the final follow up, using Hodgkinson's criteria, type 0 demarcation of the socket appeared in 9 cases, type 1 in 5 cases, type 2 in 4 cases, type 3 in 4 cases, and type 4 in 12 cases. According to Harris' criteria, there was no sign of loosening of the stem in 16 cases, however there was a possibility of loosening in 8 cases, probability in 2 cases, and definite loosening in 8 cases. The survival rate with socket loosening as the end point was 76.5% at the 10 year follow-up, 67.6% at 15-years' follow-up, and 50.9% at 20-years' follow-up. The survival rate with stem loosening as the end point was 82.4% at 10-years' follow-up, 79.4% at 15-years' follow-up, and 63.8% at 20-years' follow-up. The survival rate with prostheses loosening either socket or stem as the end point was 64.7% at 10-years' follow-up, 55.9% at 15-years' follow-up, and 34.6% at 20-years' follow-up. The survival rate with revision surgery as the end point was 100% at 10-years' follow-up, 94% at 15-years' follow-up, and 85.1% at 20-years' follow-up.

Adult↗

PubMed1996

Regulation of cytokine production by sugi allergen-pullulan conjugate.

Sugi basic protein (SBP), a major allergen of Japanese cedar (Cryptomeria japonica) pollen, conjugated to pullulan (alpha-1,4'-, alpha-1,6'-glucan) reportedly suppresses IgE anti-SBP antibody production and enhances IgG anti-SBP antibody production in mice. We analyzed cytokine production by SBP-specific T cells after stimulation with an SBP-pullulan conjugate (SBP-P), native SBP, or a mixture of SBP and pullulan. When SBP-specific T cell lines were stimulated with the SBP-P conjugate in the presence of antigen-presenting cells (APC), the production of IFN-gamma, IL-4, IL-5, and IL-10 decreased compared with the cytokine levels produced by SBP-stimulated T cells. However, when these T cells were repeatedly stimulated with the SBP-P conjugate, the production of IFN-gamma increased progressively, while that of IL-4, IL-5, and IL-10 remained decreased compared with the T cells that were repeatedly stimulated with native SBP. Stimulation of the T cells with the mixture of SBP and pullulan showed little difference in the cytokine production profile from that observed after stimulation with native SBP alone. Interestingly, when the T cell lines stimulated repeatedly with SBP-P were subsequently stimulated with native SBP, a further increase in IFN-gamma production was observed, while IL-10 production decreased. Inhibition of IL-4 production was also observed when SBP-specific Th2 clones were stimulated with SBP-P. These results indicate that stimulation of T cells with SBP-P up-regulates Th1 cytokine production, while down-regulating that of Th2. It is, therefore, conceivable that immunotherapeutic treatment with the SBP-P conjugate rather than with conventional SBP solutions is preferable for improving Japanese cedar pollen allergy.

Allergens↗

PubMed1996

Arthrodesis of knee joint by vascularized fibular graft.

Knee arthrodesis has been performed in 17 patients using vascularized fibular graft (VFG); 15 of them could be followed more than 1 year. Twelve were bone defect following tumor resection, two were traumatic bone defect, and one was intractable traumatic non-union. Three types of graft were performed; single VGF as supplement (Type I) in 5 cases, double VFG for femoral defect (Type II) in 8 cases, and double VFG for tibial defect (Type III) in 4 cases. Bone union was achieved in all cases except one. The average time to primary bone union was 4.7 months. Hypertrophy of the graft was observed significantly in some of Type II and in all of Type III. VGF is a useful method for knee fusion in patients with a large bone defect or with an intractable non-union.

Adolescent↗

PubMed1996

Latissimus dorsi musculocutaneous free flap transplantation to salvage below-elbow amputation in an emergency operation: a case report.

We used a free latissimus dorsi musculocutaneous flap (LD m-c flap) to cover a large skin defect at the stump of a forearm in an emergency operation. The patient we discuss is a 52-year-old man. Amputation at the distal one third of the left forearm occurred after catching his hand and wrist in a machine. The amputated left hand was severely damaged and there were wide skin defects. The function of the elbow joint was well preserved. Both the radius and ulna were cut 7 cm distal from the elbow joint. A 20 x 8 cm square of LD m-c flap was transplanted, to the stump of the forearm. The flap survived without incident. The range of motion of the elbow joint was from 20 degrees to 85 degrees. The prosthesis was well fitted to the stump, and the patient returned to his workshop 9 months after injury.

Amputation Stumps↗

PubMed1996

Cranial fasciitis.

We report a case of cranial fasciitis in a 14-month-old boy. The lesion grew at the site of a previous head trauma, rapidly destroying the skull. Surgery disclosed that the lesion was highly vascular and adhered to the dura. Because histopathological study of a frozen section did not show malignancy, the authors decided not to perform dural excision after total removal of the lesion. No recurrence of the lesion was seen. The authors stress that this rate fibroblastic lesion must be included in the differential diagnosis of pediatric skull tumors and that careful histopathological observation is needed to avoid extensively invasive surgery.

Craniocerebral Trauma↗

PubMed1996

Pit-1 gene expression in human pituitary adenomas using the reverse transcription polymerase chain reaction method.

OBJECTIVE: Previous studies of Pit-1 expression in human pituitary tumours have produced conflicting results. We have studied expression of Pit-1 mRNA in human pituitary adenomas, as well as in normal human and rat pituitaries, and results were compared with clinical, histological, and immunohistochemical features. In addition, expression of GH, PRL, and TSH-beta mRNA was also studied and compared with Pit-1 gene expression. MATERIAL AND METHODS: The adenomas consisted of 13 GH cell adenomas, 7 PRL cell adenomas, 3 TSH cell adenomas, 4 ACTH cell adenomas, and 10 clinically non-functioning adenomas. Expression of the Pit-1, its isoforms, and each hormone, was studied using the reverse transcription polymerase chain reaction. RESULTS: Pit-1 mRNA was expressed not only in normal human and rat pituitaries, but also in all GH, PRL and TSH cell adenomas. There was no correlation between Pit-1 transcripts and biological behaviour or histological findings in these three types of adenoma, suggesting that Pit-1 is generally required for the determination of cell phenotype but is insufficient for the regulation of hormonal activity and tumour growth in these pituitary adenomas. In addition, Pit-1 was also expressed in some ACTH cell (2/4) and non-functioning adenomas (7/10). Although there were no GH, PRL or TSH-beta transcripts in Pit-1 mRNA-negative ACTH cell and non-functioning adenomas, PRL mRNA was detected in all Pit-1 mRNA-positive ACTH cell adenomas and GH, PRL and/or TSH-beta mRNA were found in four of seven Pit-1 mRNA-positive non-functioning adenomas. In contrast, Pit-1 mRNA was expressed without any GH, PRL, or TSH-beta transcripts in only three non-functioning adenomas. These data suggest that expression of Pit-1 mRNA in these two types of adenomas can be mainly attributed to the presence of GH, PRL and/or TSH-beta mRNA expressing cells and that true Pit-1 transcripts found in non-functioning adenomas may be a rare event. Moreover, there were two cases which expressed Pit-1 alpha mRNA, but failed to show other Pit-1 isoform mRNA. There were, however, no clinical or histological differences between these two adenomas showing only Pit-1 alpha mRNA and the others expressing both Pit-1 alpha mRNA and other Pit-1 isoform mRNA. CONCLUSIONS: Pit-1 mRNA was expressed not only in GH, PRL and TSH cell adenomas but also in other types of adenoma. However, it is suggested that expression of Pit-1 mRNA in most ACTH cell and non-functioning adenomas can be attributed to GH, PRL and/or TSH-beta mRNA expressing cells. Further studies are necessary to elucidate the role of Pit-1 transcripts in the three non-functioning adenomas without GH, PRL and/or TSH-beta mRNA expression.

Adenoma↗

PubMed1996

Some problems in wrist reconstruction after tumor resection with vascularized fibular-head graft.

Restoration of wrist function was attempted in six patients with aggressive or malignant bone tumor of the distal end of the radius with free vascularized fibular graft including the fibular head, and following wide resection of tumor. There was no local recurrence in all six cases. In one case, pulmonary metastasis occurred, but was successfully treated. Secondary bone graft was necessary in two cases for non-union. Additional procedures, such as partial or total wrist fusion, were necessary in three cases due to collapse of the grafted fibular head. Corrective osteotomy or a Sauve-Kapandji procedure were also needed in two cases for improvement of forearm rotation. Grip strength ranged from 41 to 68 percent of the contralateral side, with an average of 54.6 percent in five cases; it was only 6 percent in one patient because of flexion contracture at the wrist joint. Final functional results, evaluated by a modified system of Enneking, ranged from 73 to 92 percent, with an average of 83.2 percent. Indications for this procedure seem to be limited to patients engaged in non-heavy manual work, in whom the proximal carpal row can be preserved during tumor resection, and who have given consent for additional secondary procedures, if they prove necessary.

Adult↗

PubMed1996

Peptide-mediated suppression of experimental autoimmune uveoretinitis in mice: development of a peptide vaccine.

Experimental autoimmune uveoretinitis (EAU) is an animal model of antigen-specific, Th cell-mediated, organ-specific autoimmune disease. EAU is induced by immunization of B10.A mice with interphotoreceptor retinoid-binding protein (IRBP). Pre-treatment with synthetic peptide 518-529 derived from IRBP prevented IRBP-mediated EAU. This was accompanied by augmentation of the IRBP-specific IgG1 antibody (Th2) response and down-regulation of the IRBP-specific IgG2a (Th1) response. Consistent with this is the observation that two of two T cell lines established from p518-529-primed mice produced Th2-type cytokines (IL-4 and IL-10), whereas three of three T cell lines obtained from IRBP-primed mice produced Th1-type cytokines (IL-2 and IFN-gamma). Together this suggests the possibility that p518-529 priming causes a shift from a Th1-to a Th2-dominated immune response, thereby playing a pivotal role in the prevention of IRBP-mediated EAU. Furthermore, co-transfer of cells from a CD4+ p518-529-specific T cell line prevented the development of EAU after adoptive transfer of spleen cells from mice with EAU into normal mice. These findings contribute to our understanding of the mechanism of EAU, particularly with respect to the down-regulation of Th1-initiated inflammation, and may prove valuable for designing a peptide vaccine for EAU in the future.

Adoptive Transfer↗

PubMed1996

Effects of polarity for monophasic and biphasic shocks on defibrillation efficacy with an endocardial system.

Electrode polarity has been reported to be one of the factors that affect defibrillation efficacy. We studied the influence of polarity on defibrillation efficacy when monophasic and biphasic waveforms were used with an endocardial lead system. In six anesthetized pigs, defibrillation catheters were placed in the right ventricular (RV) apex and at the junction of the superior vena cava (SVC) and right atrium. Monophasic shocks were 6 ms in duration, while for biphasic shocks the first phase was 6 ms and the second was 4 ms in duration. Four electrode configurations were tested: R:S, M (the RV electrode, cathode; the SVC electrode, anode, with a monophasic shock); S:R: S, B(the RV electrode, first phase cathode; the SVC electrode, first phase anode, with a biphasic shock); S:R, B. Defibrillation probability of success curves were determined using an up/down protocol requiring 15 shocks for each configuration. For monophasic shocks, total delivered energy at the 50% probability of success point was significantly lower when the RV electrode was an anode than when it was a cathode (R: S, M: 24.4 +/- 7.4 J [mean +/- SD] vs S:R, M: 16.4 +/- 5.5 J; P < 0.05). For biphasic shocks, total energy was not affected by polarity reversal of the electrodes (R:S, B: 8.7 +/- 1.4 J vs S:R, B: 8.4 +/- 2.5 J; P = NS). The endocardial electrode configuration with the RV electrode as an anode requires less energy for defibrillation with a monophasic but not a biphasic waveform.

Animals↗

PubMed1996

Epicardial sock mapping following monophasic and biphasic shocks of equal voltage with an endocardial lead system.

INTRODUCTION: The reason for the increased defibrillation efficacy of biphasic shocks over monophasic shock is not definitely known. METHODS AND RESULTS: In six anesthetized pigs, we mapped the epicardium after transvenous defibrillation shocks to compare the activation patterns following successful biphasic shocks with unsuccessful monophasic shocks of the same voltage. The heart was exposed and a 510-electrode sock with approximately 4-mm interelectrode spacing was pulled over the entire ventricular epicardium and sutured to the pericardium. Defibrillation catheters were placed in the right ventricular apex and in the superior vena cava. Paired monophasic 12 msec and biphasic 6/6 msec defibrillation shocks were given using an up-down protocol to keep shock strength between the defibrillation thresholds for the two waveforms so that the biphasic shock was successful while the monophasic shock was not. Activation fronts immediately following 60 paired shocks were recorded and analyzed by animated maps of the first derivative of the electrograms. The ventricles were divided into apical (I), middle (II), and basal (III) thirds, and early sites, i.e., the sites from which activation fronts first appeared on the epicardium following the shock, were grouped according to their location. Postshock intervals, i.e., the time from the shock until earliest epicardial activation occurred, were also determined. No ectopic activation fronts followed the shock in 20 biphasic episodes. In the other 40 paired episodes, the number of early sites was smaller after biphasic shocks than after monophasic shocks [monophasic: 198 (total), 3.3 +/- 0.9 (mean +/- SD) per shock episode; biphasic: 67, 1.1 +/- 1.0, P < 0.05]. For biphasic but not monophasic shocks, early sites were less likely to arise from the middle (II) and basal (III) thirds than from the apical third (I) [monophasic: I: 84 (42%), II: 68 (34%), III: 46 (23%); biphasic: I: 49 (73%), II: 10 (15%), III: 8 (12%), P < 0.05]. Postshock intervals were significantly shorter for monophasic shocks (54 +/- 14 msec) than for biphasic shocks (75 +/- 23 msec, P < 0.05). CONCLUSION: The decreased number of activation fronts and the longer delay following the shock for the earliest epicardial appearance of those activation fronts that do occur may be responsible for the increased defibrillation efficacy for biphasic shocks.

Animals↗

PubMed1996

Mizoribine reduces urinary protein excretion in rats given puromycin aminonucleoside.

Mizoribine (MZR), a purine nucleoside antibiotic, is an effective immunosuppressive agent that prevents rejection reactions after kidney transplantation in humans. The present study was performed to examine the effect of MZR on nephrosis produced in rats given puromycin aminonucleoside (PAN). Urinary protein excretion in rats injected with PAN and MZR (PAN + MZR rats) was shown to be reduced significantly in comparison with rats given only PAN (PAN rats). Although mild hypoproteinemia persisted during the experimental period in PAN + MZR rats, no loss of body weight or state of malnutrition was observed. The reduction of serum IgG and C3 was reversed by administration of MZR. Polyethyleinamine (PEI) staining of renal sections showed increased numbers of anionic sites in PAN + MZR rats in comparison with PAN rats, suggesting that MZR improved the permselectivity of the glomerular basement membrane (GBM). Moreover, the production of thromboxane B2 (TxB2) was significantly inhibited in PAN + MZR rats compared with PAN rats. No serious adverse effects of MZR were observed after a large dose of the agent. It is possible that restoration of the charge barrier of the GBM damaged by PAN, or reduction of TxB2 production by the glomeruli may underlie the reduction of protein excretion induced by administration of MZR.

Animals↗

PubMed1996

Common antigenicity between Yersinia enterocolitica-derived heat-shock protein and the retina, and its role in uveitis.

Yersinia enterocolitica-derived heat-shock protein (HSP60) was recently demonstrated to be associated with certain systemic autoimmune diseases. A role for HSP60 is also suspected in the pathogenesis of some types of uveitis believed to involve autoimmune mechanisms, such as Behçet's disease. We report our results on the role of HSP60 in patients with uveitis. HSP60 was subjected to electrophoresis in immunoblot analysis, and then allowed to react with sera from patients with uveitis in order to detect the presence of anti-HSP60 antibody. Tissue extracts from human and bovine retina were also electrophoresed, and then treated with anti-HSP60 monoclonal antibodies to determine whether or not the antibodies recognized ocular tissues. Immunoblot analysis revealed anti-HSP60 antibodies in patient sera. Furthermore, anti-HSP60 monoclonal antibodies reacted against the 60-kD protein derived from human and bovine retinal extracts. These immunological cross-reactions between HSP60 and the retina demonstrate a common antigenicity. Furthermore, detection of specific antibody against HSP60 in patient sera suggests that this common antigenicity between HSP60 and the retina may be related to the pathogenesis of uveoretinitis in some cases.

Animals↗

PubMed1996

Vasospastic angina in patients with systemic triglyceride storage disease with Jordans' anomaly and cardiomyopathy.

Vasospastic angina was demonstrated clinically and angiographically in a 54-year-old patient with systemic triglyceride storage disease and cardiomyopathy. He and his younger sister had been diagnosed in 1985 as having systemic triglyceride storage with Jordans' anomaly. In 1993, he began complaining of rest and effort chest pain in the morning, which was accompanied by ST depression by ECG. Sublingual nitroglycerine was effective for treating this pain. Intracoronary injection of acetylcholine induced severe coronary vasoconstriction in the left anterior descending artery. Left ventricular contraction was diffusely impaired. Deposits of numerous triglyceride droplets and a decrease in the density of myofibrils in cardiocytes were found in the specimens obtained by endomyocardial biopsy. The impaired left ventricular contraction may have been due to the changes in myocardial cells. His sister complained of a similar chest pain that was completely controlled by calcium channel antagonis. Thus, our cases demonstrated vasospastic angina associated with cardiomyopathy secondary to systemic triglyceride storage disease with Jordans' anomaly, though the causal relationship between these conditions remains unclear.

Adult↗

PubMed1996

Femoral neck fracture following avascular necrosis of the femoral head.

Four cases of femoral neck fracture following avascular necrosis of the femoral head were studied histologically. All four patients were women who had received steroid therapy, three of them for systemic lupus erythematosus and the other for idiopathic thrombocytopenic purpura. Two types of fracture were found according to the site and the mechanism of fracture. One was at the junction between the necrotic bone and the repairing bone, and it can thus be regarded as a stress fracture. The other type of fracture commenced at the superior portion of the junction between the femoral head and neck, which was weak due to the repair reaction. The fracture line extended to the inferior cortex of the femoral neck, as often occurs in the elderly. In one patient, the femoral neck fracture was the first sign of avascular necrosis of the femoral head.

Adrenal Cortex Hormones↗

PubMed1996

Visceral leishmaniasis misdiagnosed as malignant lymphoma.

Visceral leishmaniasis is a chronic infectious disease caused by a protozoan parasite of the genus Leishmania, characterized by intermittent fever, monocytosis, hepatosplenomegaly and hypergammaglobulinemia. This morbid condition is rather difficult to diagnose correctly, especially at its early stage, because it is rarely encountered in Japan. Recently we treated a case of visceral leishmaniasis in which the patient was misdiagnosed as malignant lymphoma, and went through splenectomy and steroid administration, which made the diagnosis more difficult.

Adult↗

PubMed1996

[Cytomegalovirus retinitis and Pneumocystis carinii choroidopathy in a patient with AIDS].

A case of Pneumocystis carinii (P. carinii) choroidopathy is reported. The patient was a 17-year-old man with acquired immunodeficiency syndrome (AIDS) who developed bilateral, multifocal, yellow-white, round, flat choroidal lesions ranging in size from 1/8 to 1/6 of the disc diameter while undergoing treatment for cytomegalovirus retinitis. He had had P. carinii pneumonia 43 months previously, and received inhaled pentamidine as suppressive therapy. Over a 4-week period of observation, the choroidal lesions appeared to enlarge slowly and increased in number in the posterior pole, with no clinical evidence of intraocular inflammation and retinal involvement. He was diagnosed as having P. carinii choroidopathy and treated with intravenous pentamidine. Three months after systemic pentamidine therapy was begun the choroidal lesions disappeared. Despite the fact that P. carinii choroidopathy is a rare opportunistic ocular infection, ophthalmic manifestations may be an important initial marker of extrapulmonary disseminated infection in some patients. Therefore we recommend ophthalmologic examinations in patients with AIDS who receive long-term aerosolized pentamidine prophylaxis for pneumonia.

AIDS-Related Opportunistic Infections↗

PubMed1996

[Single-stage surgery for annulo aortic ectasia, Stanford type-A aortic dissection and pectus excavatum in a patient with Marfan's syndrome].

A 43-year-old female was hospitalized on October 25, 1993, due to severe back pain. She was diagnosed with annulo aortic ectasis, Stanford type-A acute aortic dissection and pectus excavatum caused by Marfan's syndrome. On November 30, 1993, single-stage surgery was performed, including modified Bentall procedure, aortic arch replacement, elephant trunk method and sternoplasty. Concerning the procedure for pectus excavatum, sternoplasty was selected because we thought that sternoplasty could endure the long procedure which would cause infection compared with sternal turnover. Postoperative course was satisfactory, and she is well 18 months after surgery.

Adult↗

PubMed1996

[Coronary artery bypass grafting for ischemic heart disease associated with acromegaly: a case report].

Coronary artery bypass grafting (CABG) for ischemic heart disease associated with acromegaly has never been reported in Japan, though coronary artery sclerosis is known as complicating factor in acromegaly. A 44-year-old man with ischemic heart disease was admitted to our hospital and emergency percutaneous transluminal coronary recanalization was performed. After admission, he was diagnosed as acromegaly from endocrinological studies and operated on CABG. The peri- and post-operative course was uneventful in spite of our fear for complications due to acromegalic heart muscle disease.

Acromegaly↗