Search PubMed⌕ Search

Biomedical subjects

T Ueda

Publications and source records attributed to T Ueda.

At least 271 records · Page 15Linked to original sources
PubMed1996

Nitric oxide concentrations in the follicular fluid and apoptosis of granulosa cells in human follicles.

To study the relationship between follicular atresia, apoptosis, and nitric oxide (NO) generation in follicular development, steroidogenesis, NO levels in follicular fluid and apoptosis were analysed in the various sized follicles of women receiving ovarian stimulation with human menopausal gonadotrophin (HMG)-human chorionic gonadotrophin (HCG) treatments for in-vitro fertilization (IVF)-embryo transfer. The follicles were divided into three groups by diameter: large follicle, > or = 18 mm; medium follicle, > or = 12 and < or = 15 mm; small follicle, < or = 10 mm. Follicular fluid was obtained from 20 women 34 h after HCG administration, and the concentrations of oestradiol, progesterone and testosterone, and nitrite, nitrate, arginine and citrulline were measured. Granulosa cells obtained from each group of follicular fluid were stained with Hoechst dye, and nuclear morphology was examined by a fluorescence microscopy. Oestradiol and progesterone concentrations in large follicles were significantly (P < 0.01) higher than those in medium or small follicles, and testosterone concentrations in small follicles were significantly (P < 0.01) higher than those in large follicles. There were no significant differences in the concentrations of nitrite, nitrate, arginine and citrulline among three groups. The percentage of apoptotic cells with nuclear fragmentation was significantly (P < 0.01) higher in small follicles than in large follicles. The present results suggested that small follicles with poor response to HMG may undergo atresia through apoptosis. No significant difference in the follicular NO level between large and small follicles led us to speculate on a different responsiveness to NO in these two types of follicles.

Adult↗
PubMed1996

A mutation study of catalytic residue Asp 52 in hen egg lysozyme.

We constructed a system for the expression and secretion of mature hen lysozyme by yeast using an intermediate "secretion-signal cassette" vector, pKP1700, containing the yeast invertase signal sequence and an expression vector, pAM82, for secretion and maturation of the enzyme. Using this system, mutants of hen lysozyme were produced and the catalytic mechanism in hen lysozyme was definitely confirmed. The hydrolytic activity of D52A as to substrate (NAG)6 at pH 5.0 was obviously decreased to one-four hundredth of that of the wild type. The acidic limb of the pH-activity profile observed for the wild-type was not observed for D52A, and the pKa of Glu 35 on the alkaline limb was seen for both enzymes. Moreover, no structural change was detected on X-ray analysis of D52A. Therefore, we confirmed that dissociated Asp 52 assists catalysis by producing an electrostatic field and by stabilizing the oxocarbonium ion intermediate in the dissociated form.

Animals↗
PubMed1996

Stabilization of lysozyme by introducing N-glycosylation signal sequence.

We designed mutant lysozymes with N-glycosylation signal sequences (Asn48-Gly49-Thr-50 and Asn87-Ile88-Thr89) by substituting Asp to Asn at positions 48 and 87. When these mutant lysozymes were expressed by using yeast (Saccharomyces cerevisiae) in Burkholder minimum medium, N-glycosylation occurred in both lysozymes. The mutant lysozyme with the oligosaccharide at Asn87 showed a similar character to a reported polymannosyl lysozyme [Nakamura, Takasaki, Kobayashi, and Kato (1993) J. Biol. Chem. 268, 12706-12712; Kato, Takasaki, and Ban (1994) FEBS Lett. 355, 76-80]. As judged from the thermodynamic stabilities of the lysozymes obtained by the guanidine hydrochloride denaturation method, the oligosaccharide-bearing mutant lysozymes were more stable by 0.4-1.6 kcal/mol than the corresponding unglycosylated lysozymes. Therefore, it is suggested that the introduction of an N-glycosylation signal sequence into a protein is an effective means to increase the stability of the protein.

Amino Acid Sequence↗
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↗