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Biomedical subjects

T Ueda

Publications and source records attributed to T Ueda.

At least 289 records · Page 16Linked to original sources
PubMed1996

Analysis of the transition state in the unfolding of hen lysozyme by introduction of Gly-Pro and Pro-Gly sequences at the same site.

We developed a sensitive method for analyzing the conformation of the transition state in the unfolding of hen lysozyme. The activation free energy changes of mutant lysozymes with Gly-Pro and Pro-Gly sequences at the same sites (Gly47Pro47', Pro47Gly47', Gly101Pro102, Pro101Gly102, Gly117Pro118, Pro117Gly118, Gly121Pro122, and Pro121Gly122 lysozymes) were obtained for the unfolding in aqueous solution at pH 5.5 and 35 degrees C. Since we had shown that the difference of energies of the unfolded state in lysozymes having an introduced Gly-Pro or Pro-Gly sequence at the same site was much smaller than the difference of energies of the folded states [Motoshima, H., Ueda, T., Hashimoto, Y., Tsutsumi, M., and Imoto, T. (1995) J. Biochem. 118, 1138-1144], we could estimate the difference of energies of the folded and the transition states unequivocally. We defined the phi-value as the ratio of the difference in the free energy change in the transition state to that in the free energy change in the folded state between lysozymes with Gly-Pro and Pro-Gly sequences at the same site. The phi-values gave information on how much the mutated sites retained the folded structure in the transition state. These values were 0.45 around position 47, which is located in the beta-sheet structure, 0.12 at position 101-102, which is located in the loop at the upper part of the active site, 0.17 at position 117-118, which is located in the beta-turn and 0.64 at position 121-122, which is located in the 3(10)-helix. Therefore, in the transition state in the unfolding of lysozyme, it was found that the 3(10)-helical region had a similar structure to the intact region, while both the beta-turn and the loop at the upper part of the active site were considerably unfolded. The beta-sheet structure was also moderately disrupted in the transition state.

Animals↗
PubMed1996

Pyridine-promoted factor- and energy-free peptide synthesis systems prepared from various organisms including prokaryote, eukaryote, and mitochondria.

We demonstrate here that ribosomes from not only Escherichia coli and Thermus thermophilus [Nitta et al. (1994) J. Biochem. 115, 803-807; ibid., (1995) 118, 841-849] but also yeast and bovine mitochondria catalyze peptide synthesis promoted by a high concentration of pyridine in the absence of soluble protein factors and chemical energy sources, and compare some characteristic features of the reactions among these organisms. Sensitivities against antibiotics, chloramphenicol and cycloheximide, showed the same tendency to those in the in vitro aqueous translation systems of these organisms, suggesting that the basic mechanism for peptide synthesis is the same among these organisms. The optimal concentration of pyridine was centered at 50% for all systems, although the dependencies on the pyridine concentrations and the yields of the products were different from one another. All these systems required Mg2+, and only mitochondrial system showed the extra Mn(2+)-requirement, which enhanced the yield by several fold. The optimum reaction temperatures coincided closely with the growing temperatures of the organisms except for the mitochondrial system, which showed the highest activity above 80 degrees C. The rationale for these observations remains to be solved.

Animals↗
PubMed1996

Situation of monomethoxypolyethylene glycol covalently attached to lysozyme.

We selectively introduced monomethoxypolyethylene glycol (mPEG) 5000, 2000, and 550 into Asp119 in lysozyme. To examine how the mPEGs were present on the surface of the modified lysozyme, the activities, binding abilities to the Fab fragment of anti-lysozyme monoclonal antibody, net charges and nuclear magnetic resonance (NMR) spectra of mPEG lysozymes were examined. With the increase in molecular weight of mPEG, the activities and binding abilities to the Fab of mPEG lysozyme decreased. However, introduced mPEG5000 did not cause complete inhibition of the activities and binding abilities to the Fab, while the maximum length of mPEG5000 was so great that it largely covered the surface of the lysozyme molecule. Analyses of the net charges and NMR suggested that the introduced mPEG preferentially assumed a folded conformation on the surface rather than spread all over the surface. Based on the structure of mPEG lysozyme, the mechanism of the reduced immunogenicity of mPEG lysozyme was discussed.

Antibodies, Monoclonal↗
PubMed1996

Changes in histologic grade and argyrophilic nucleolar organizer regions during progression of prostate cancer.

To determine the changes in histologic features during the course of prostate cancer under long-term endocrine therapy, histologic grade and argyrophilic nucleolar organizer regions (AgNORs) were examined in specimens before treatment, at relapse, and at cancer death. A total of 29 patients who had received therapy and died of prostate cancer were evaluated. Among the 29 cases, biopsy tissues before treatment (25 cases) and during progression from endocrine therapy (10 cases) were compared with autopsy specimens. Histologic grade was determined by the method of Gleason, and the number of AgNORs in cancer cells was counted. Survival of the patients was compared with the histologic features. There was a tendency for a higher grade of cancer during the clinical course. Moreover, a statistically significant increase in the number of AgNORs was observed from pretreatment biopsy to autopsy. Upon comparison of metastatic sites with local cancer at autopsy, no significant difference was noticed in terms of histologic grade or AgNOR count. Although there was no correlation between the number of AgNORs and survival after initial treatment, an inverse relationship was demonstrated between the number of AgNORs and survival in patients with systemic progression after endocrine therapy. In conclusion, prostate cancer shows an increase of malignant potential, as assessed by histologic grade and the number of AgNORs. Patients with cancer of high proliferative ability showing high grade and greater numbers of AgNORs have poorer prognosis from progression.

Biopsy↗
PubMed1996

Effective renaturation of denatured and reduced immunoglobulin G in vitro without assistance of chaperone.

IgG is an oligomeric protein that consists of two heavy and two light chains. To form the oligomer, a highly concentrated protein would be required on renaturation. On the other hand, refolding of proteins at high concentration often led to aggregation. Therefore, denatured and reduced oligomeric protein scarcely refolded to the native structure. As was expected, the folding yield of the denatured and reduced IgG was below 5% under the condition employed in rapid dilution. The low folding yield was elucidated to be due to assembly or aggregation. Using a renaturation method previously developed to depress aggregation effectively by means of slow dialysis, the refolding yield of the denatured and reduced IgG at above 1 mg/ml was above 70%. Most of the refolded IgG was identical with the intact material based on analyses by affinity chromatography and SDS-PAGE.

Chromatography, Affinity↗
PubMed1996

Effect of additives on the renaturation of reduced lysozyme in the presence of 4 M urea.

Reduced lysozyme was renatured by sulfhydryl-disulfide interchange reactions at pH 8.0 in the presence of 4 M urea, with or without additives at 40 degrees C. In the absence of additives, the final folding yield of reduced lysozyme was approximately 40%. In the presence of sarcosine, glycerol, ammonium sulfate, N-acetyl glucosamine and glucose, its folding yields increased in all cases. In particular, yields increased up to 90% in the presence of 4 M sarcosine. On the other hand, the melting temperatures of lysozyme with or without additives in 0.02 M citrate buffer (pH 6.0) were evaluated using differential scanning calorimetry. In the absence of additive, the melting temperature of lysozyme was 73.8 degrees C. In the presence of additives, all melting temperatures were higher than that of lysozyme in the absence of additives. Moreover, there was a good correlation on addition of additives between an increase in the folding yield of reduced lysozyme with 4 M urea and an increase in the melting temperature without 4 M urea. Therefore, we conclude that additives, which stabilize native lysozyme, are effective at increasing the folding yield of reduced lysozyme in 4 M urea.

Acetylglucosamine↗
PubMed1996

Dedifferentiated liposarcoma of the subcutis.

This report describes an 82-year-old woman with dedifferentiated liposarcoma, an extremely rare neoplasm of the subcutis. The patient had first recognized a very soft mass in the anterolateral part of the right thigh more than 20 years earlier, but because the tumor showed little change over this period, she did not seek treatment. She recently noticed a hard, rapidly growing mass within the former tumor. Both magnetic resonance imaging and axial computed tomography revealed a subcutaneous fatty lesion measuring 12 x 7 x 4 cm and a well-delineated mass-like area (4 x 3 x 3 cm) of nonfatty tissue within the lesion. Histologically, the former was a mature lipomatous tumor with broad fibrous septa containing some atypical stromal cells, and the latter was a much more cellular, spindle cell tumor with a malignant fibrous histiocytoma-like pattern. The authors propose that dedifferentiated liposarcoma is not restricted to the deep soft tissues and may develop in the subcutis and further suggest appropriate surgical management for well-differentiated fatty tumors of subcutaneous origin.

Aged↗
PubMed1996

Prosthetic reconstruction for periacetabular malignant tumors.

This article reports the reconstruction method and functional results of a newly designed tumor hip prosthesis with a constrained joint mechanism which was used after treatment for 13 primary and 5 metastatic periacetabular malignant bone tumors. The overall 5-year survival rate for patients with primary tumors (n=13) was 50%. The local recurrence rate was 30%. More than 90% of the patients whose hips were reconstructed with the constrained tumor hip prosthesis experienced pain relief and were able to walk with a cane. No patients had greater than 3 cm shortening of the involved limb. Infection was the most serious complication. This prosthesis restored iliofemoral stability after surgical resection of periacetabular malignant tumors.

Acetabulum↗
PubMed1996

Subdural hemorrhage caused by de novo aneurysm complicating extracranial-intracranial bypass surgery: case report.

A case of a de novo aneurysm leading to subdural hemorrhage after right extracranial-intracranial bypass surgery is described. After an uneventful 2-month postoperative course, the patient experienced sudden onset of occipital headache with vomiting. Radiological study disclosed an acute subdural hematoma in the right temporo-occipital region and a newly formed aneurysm at the site of patent superficial temporal artery-middle cerebral artery anastomosis. The anastomotic portion with the ruptured aneurysm was resected en bloc after alternative occipital artery-middle cerebral artery bypass, and the cut end of the superficial temporal artery was successfully used for end-to-side reanastomosis to the other middle cerebral artery branch. The histological examination of the ruptured aneurysm revealed the features of a true aneurysm.

Aged↗
PubMed1996

Successful percutaneous transluminal angioplasty for basilar artery stenosis: technical case report.

OBJECTIVE: We report our experience with low-pressure submaximal percutaneous transluminal angioplasty (PTA) for basilar artery stenosis of > 90%. This treatment resulted in a favorable clinical course and satisfactory improvement of posterior cerebral circulation. CLINICAL PRESENTATION: This technique was applied to two patients with repeated basilar arterial ischemic symptoms that were resistant to medical treatment. INTERVENTION: Low-pressure submaximal PTA was performed with use of a smaller balloon (2.0-mm diameter) and lower inflation pressure (< or = 303,975 Pa) than previously reported. RESULTS: Despite basilar arteries with 50 and 60% residual stenosis, the clinical symptoms and hemodynamics in the basilar arterial territory as assessed using single photon emission tomography were markedly improved after PTA. Follow-up angiographic evaluation demonstrated the absence of restenosis, and improved cerebral blood flow was maintained. Neither patient has developed any new neurological deficits 10 and 13 months after the PTA, respectively. CONCLUSION: Submaximal PTA may have reduced the high risk associated with this procedure, and cerebral blood flow measurement may be a useful tool to assess whether this technique will produce adequate results.

Aged↗
PubMed1996

Significant elevation of serum human hepatocyte growth factor levels in patients with acute pancreatitis.

Serum levels of human hepatocyte growth factor (HGF) were determined in 38 patients with acute pancreatitis by an enzyme-linked immunosorbent assay. The mean value of serum HGF levels on admission in the 38 patients was 1.69 +/- 0.40 (SEM) ng/ml. In 35 patients, serum HGF levels were found to be positive (> 0.39 ng/ml), with an incidence of 92.1%. In 17 patients, they were > 1.0 ng/ml, which was the cutoff value for fulminant hepatic failure. Serum HGF levels in the patients with severe acute pancreatitis (2.30 +/- 0.61 ng/ml; mean +/- SEM) were significantly higher than those in the patients with mild and moderate acute pancreatitis (0.63 +/- 0.06 ng/ml). Sixteen of seventeen patients whose serum HGF levels were > 1.0 ng/ml were evaluated as severe acute pancreatitis. Serum HGF levels were significantly elevated in the patients with higher Ranson scores, higher APACHE II scores, or higher computed tomography grades. Serum HGF levels in the patients with organ dysfunction (liver, kidney, or lung) were significantly higher than those in the patients without organ dysfunction. Moreover, serum HGF levels on admission in the nonsurvivors (3.17 +/- 1.30 ng/ml) were significantly higher than those in the survivors (1.22 +/- 0.33 ng/ml). The mortality rate of the patients showing serum HGF levels > 2.0 ng/ml on admission was 50%. In the patients with a lethal outcome, the mean serum HGF level remained constantly > 2.50 ng/ml during hospitalization. The serum HGF level reflected the clinical course of the disease rapidly and distinctly. Serum HGF levels increased with complications such as organ failure, infected pancreatic necrosis, and sepsis and decreased with successful intensive and surgical treatments. These results suggest that serum human HGF levels may reflect the severity, organ dysfunction, and prognosis in acute pancreatitis.

Acute Disease↗
PubMed1996

An Arabidopsis gene isolated by a novel method for detecting genetic interaction in yeast encodes the GDP dissociation inhibitor of Ara4 GTPase.

The Arabidopsis Ara proteins belong to the Rab/Ypt family of small GTPases, which are implicated in intracellular vesicular traffic. To understand their specific roles in the cell, it is imperative to identify molecules that regulate the GTPase cycle. Such molecules have been found and characterized in animals and yeasts but not in plants. Using a yeast system, we developed a novel method of functional screening to detect interactions between foreign genes and identified this Rab regulator in plants. We found that the expression of the ARA4 gene in yeast ypt mutants causes exaggeration of the mutant phenotype. By introducing an Arabidopsis cDNA library into the ypt1 mutant, we isolated a clone whose coexpression overcame the deleterious effect of ARA4. This gene encodes an Arabidopsis homolog of the Rab GDP dissociation inhibitor (GDI) and was named AtGDI1. The expression of AtGDI1 complemented the yeast sec19-1 (gdi1) mutation. AtGDI1 is expressed almost ubiquitously in Arabidopsis tissues. The method described here indicates the physiological interaction of two plant molecules, Ara4 and GDI, in yeast and should be applicable to other foreign genes.

Amino Acid Sequence↗
PubMed1996

Improvement of bone disease with increased dose of glucocerebrosidase in a Gaucher disease patient who had a bone lesion presenting during low-dose enzyme replacement therapy.

In recent years, enzyme replacement therapy has been shown to be useful for the treatment of Gaucher disease. A 10 year old Japanese boy with Gaucher disease underwent splenectomy at the age of 5 years and received enzyme replacement therapy from the age of 6 years. He had avascular necrosis of the bilateral femoral heads, which was not seen at the beginning of the therapy, without deterioration of hematological variables during maintenance therapy. The enzyme dosage was increased from 20 to 120 IU/kg per month resulting in an improvement of the clinical symptoms and bone lesion. In enzyme replacement therapy, dose increase is considered to be essential for improvement in bone disease; however, it is important to watch for the development of bone lesion.

Child↗
PubMed1996

Distribution of human herpesvirus 6 and varicella-zoster virus in organs of a fatal case with exanthem subitum and varicella.

The distribution of human herpesvirus 6 (HHV-6) and varicella-zoster virus (VZV) was examined in autopsy samples from a fatal case with both virus infections. A 9-month-old boy developed convulsive seizures followed by macular skin rashes, rapidly progressed to brain death, and died 15 days after the onset, when signs of varicella were noted. An isolation of HHV-6 from blood and evaluation of antibody activities to various viral agents including HHV-6 were performed before his death. Postmortem examinations included: (i) isolation of HHV-6 and VZV from tissues or organs; (ii) detection of both virus antigens in tissues or organs by an indirect immunofluorescent assay using monoclonal antibodies to both viruses; (iii) amplification of both viruses and human herpesvirus 7 DNA sequences by a nested polymerase chain reaction assay; and (iv) endonuclease digestion of amplified products of HHV-6 DNA for differentation of variants A and B. Human herpesvirus 6 DNA was detected in peripheral blood mononuclear cells (PBMC) and plasma obtained at the eruptive stage but present only in PBMC 15 days after, indicating the primary infection with HHV-6, although the virus was not isolated from the same blood sample and a significant rise in the antibody titers to HHV-6 was not observed. Both virus antigens and DNA were detected in various tissues or organs obtained at autopsy, but only VZV was isolated from these samples, suggesting disseminated infection with both viruses in an infant. All the amplified products of HHV-6 DNA were variant B. Among the findings for the distribution of virus antigens, it was noteworthy that HHV-6 antigen was demonstrated in the endothelial cells of small vessels in the frontal lobe of the brain. There was no evidence of HHV-7 infection. These data indicate that the primary HHV-6 infection closely followed by the primary VZV infection had the potential hazard of an unexpected and apparently life-threatening event, in which disseminated infections with both viruses were noted in multiple tissues or organs including the brain.

Antibodies, Viral↗
PubMed1996

Action spectrum for sporulation and photoavoidance in the plasmodium of Physarum polycephalum, as modified differentially by temperature and starvation.

The plasmodium of the myxomycete Physarum polycephalum sporulates in bright natural environments, suggesting a relationship between photobehavior and sporulation. Thus, the action spectra for two light-dependent phenomena as well as the effects of other environmental conditions have been studied. Sporulation like photo-avoidance responded to UVC (near 270 nm) and near IR (near 750 nm) in addition to the well-documented UVA (near 350 nm) and blue (near 460 nm) regions. Sporulation and photoavoidance had similar sensitivities in the shorter wavelengths, while the former was about 100 times more sensitive in near IR. The plasmodium moved away from light in a wide spectral range. Starvation and high temperature at 31 degrees C (25 degrees C in standard conditions) reduced photoavoidance to UVA and to blue light, respectively. A high fluence rate of UVC suppressed the rhythmic contraction of the plasmodium, and the action spectrum peaked at 270 nm. These results indicate that the Physarum plasmodium may stay at brighter places not by positive phototaxis but by weakening the negative phototaxis to sunlight or by other possible taxes such as hydrotaxis. There may be at least four different photo-systems in the plasmodium.

Animals↗
PubMed1996

T lymphocytes and silica-induced pulmonary inflammation and fibrosis in mice.

BACKGROUND: Silica-induced pulmonary inflammation and fibrosis in animals provides a good model for chronic pulmonary inflammation and fibrosis. Although lymphocytes are implicated in the pathogenesis of pulmonary fibrosis, experimental models using silica-treated athymic nude mice have not been successful in showing the fibrogenic mechanism regulated by T cells. The aim of this study was to re-evaluate the role of T lymphocytes in the development of silicosis by comparing the response to silica administration of nude athymic mutants with that of euthymic animals. METHODS: Suspensions of silica particles were transnasally administered to nude athymic mice (Balb/c nu/nu) as well as to their euthymic littermates (Balb/c nu/+). The degree of pulmonary inflammation and fibrosis was assessed on days 14, 28, and 56 based upon histological observation, analysis of collagen deposition in the lungs, and analysis of the cellular constituent, protein, and phospholipid content in the bronchoalveolar lavage fluid. RESULTS: Histologically, athymic mice developed less severe interstitial pneumonitis than euthymic mice. In euthymic mice the lung hydroxyproline content increased with time after silica administration from 6.48 (0.38) micrograms hydroxyproline/mg dry lung weight on day 0 to 8.87 (0.41) micrograms/mg on day 56. A gradual increase in lung hydroxyproline content was also observed in athymic mice but the increase was significantly smaller than in euthymic mice (6.63 (0.43) micrograms/mg on day 0, 7.90 (0.19) micrograms/mg on day 56). Administration of silica resulted in an increase in the number of macrophages and neutrophils and in the total protein and phospholipid content of the bronchoalveolar lavage (BAL) fluid in both mouse strains. No significant difference was detected between athymic and euthymic mice in the numbers of macrophages, but the increase in neutrophils in the BAL fluid of athymic mice was significantly smaller than in euthymic mice on days 14 and 56. The total protein and phospholipid content of the BAL fluid from athymic mice was lower than that from euthymic mice. CONCLUSIONS: T lymphocytes appear to be involved in the pathogenesis of silica-induced pneumonitis. Since pulmonary fibrosis develops even in nude athymic mice, T cells do not seem to play a primary part in fibrogenic response but they regulate, at least to some extent, the response of inflammatory cells and fibrogenesis of the lung.

Animals↗