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Biomedical subjects

R Sato

Publications and source records attributed to R Sato.

At least 73 records · Page 4Linked to original sources
PubMed2000

Spectroscopic characterization of the conformational adaptability of Bombyx mori apolipophorin III.

Apolipophorin III (apoLp-III) from the silkmoth, Bombyx mori, has been over-expressed in Escherichia coli, purified and characterized. Far-UV CD spectroscopic analysis revealed 65% alpha-helix secondary structure. Near-UV CD spectra obtained in buffer or complexed with dimyristoylglycerophosphocholine (DMPC), provided evidence that apoLp-III alpha-helices reorient upon interaction with lipid, indicative of a protein conformational change. In guanidine hydrochloride (GdnHCl) denaturation studies, a transition midpoint of 0.33 M was observed, corresponding to a DeltaGDH2O = 2.46 kcal. mol-1. Fluorescence studies of the sole tryptophan residue (Trp40) in apoLp-III revealed an emission lambdamax = 327 nm. Compared to free tryptophan, Stern-Volmer constants (KSV) for acrylamide and KI quenching of Trp40 fluorescence were decreased by 20-fold and sevenfold, respectively. In studies of apoLp-III-DMPC disc complexes, far-UV CD spectroscopy revealed an increase in alpha-helix content to approximately 85% and a ninefold increase in the GdnHCl-induced denaturation transition midpoint to 3 M. In studies of lipid interaction, apoLp-III was shown to disrupt both negatively charged and zwitterionic phospholipid bilayer vesicles, transforming them into discoidal complexes. Characterization of apoLp-III-DMPC discs, using 5-doxyl or 12-doxyl stearic acid as lipid-based quenching agents, revealed that Trp40 localizes near the phospholipid polar head groups. KSV values for acrylamide and KI quenching of intrinsic fluorescence of apoLp-III-DMPC discs indicate that Trp40 is embedded in the lipid milieu, with little or no accessibility to the aqueous quenchers. Given the large amount of alpha-helix in apoLp-III, the data presented support a model in which amphipathic alpha-helical segments are stabilized by helix-helix interactions and lipid association induces a protein conformational change which results in substitution of helix-helix interactions for helix-lipid contacts.

Animals↗
PubMed2000

Endothelin-1 and right-sided heart failure in rats: effects of an endothelin receptor antagonist on the failing right ventricle.

The development of pulmonary hypertension (PH) causes right-sided heart failure. We investigated whether chronic treatment with the endothelin-A- (ETA) receptor antagonist BMS-193884 in rats with monocrotaline- (MCT) induced PH improves right-sided heart failure. Administration of BMS-193884 (100mg/kg) was commenced on the day before treatment with MCT. At 19 days, hemodynamics were measured under anesthesia and hearts were removed. The right ventricular systolic pressure (RVSP), an indicator for pulmonary hypertension, was remarkably elevated in the PH group compared with the normal control group. BMS-193884 effectively prevented this elevation. The central venous pressure, an indicator for right-sided heart failure, was markedly increased in the PH group. This increase was reduced to the normal level by BMS-193884. In the failing right ventricle of the PH group, the expression of atrial natriuretic peptide (ANP) mRNA, which is a molecular marker for the failing heart, was markedly increased. BMS-193884 greatly prevented this increase. The present study suggests that ET-1 contributes to the right-sided heart failure caused by PH and that an ETA-receptor antagonist is a beneficial drug which improves both hemodynamics and cardiac gene expression in the failing right ventricle.

Animals↗
PubMed2000

Uterine leiomyoma causing massive ascites and left pleural effusion with elevated CA 125: a case report.

A 51-year-old patient presented with an abdominal mass and ascites as well as a left pleural effusion. Her serum CA125 was 820 U/ml. Surgical exploration revealed a benign leiomyoma of the uterus without malignant cytology in the ascites. Postoperatively, the pleural effusion was resolved dramatically and the CA125 decreased to the normal range after 4 months post-operatively. This is an extremely rare case of pseudo-Meigs' syndrome caused by uterine leiomyoma.

Ascites↗
PubMed2000

An oligoribonuclease gene in Streptomyces griseus.

In Streptomyces griseus, A-factor (2-isocapryloyl-3R-hydroxymethyl-gamma-butyrolactone) serves as a microbial hormone that switches on many genes required for streptomycin production and morphological development. An open reading frame (Orf1) showing high sequence similarity to oligoribonucleases of various origins is present just downstream of adpA, one of the A-factor-dependent genes. Orf1 was named OrnA (oligoribonuclease A) because it showed 3'-to-5' exo-oligoribonuclease activity, releasing [(32)P]CMP from ApCpC[(32)P]pC used as a substrate. Reverse transcription-PCR and S1 nuclease mapping analyses revealed that ornA was transcribed from two promoters; one was a developmentally regulated, A-factor-dependent promoter in front of adpA, and the other was a constitutive promoter in front of the ornA coding sequence. Transcription of ornA was thus additively enhanced at the initiation stage for secondary metabolism and aerial mycelium formation. ornA-disrupted strains grew slowly and scarcely formed aerial mycelium. ornA homologues were distributed in a wide variety of Streptomyces species, including S. coelicolor A3(2), as determined by Southern hybridization analysis. Disruption of the ornA homologue in S. coelicolor A3(2) also caused phenotypes similar to those of the S. griseus DeltaornA strains. The OrnA oligoribonucleases in Streptomyces species are therefore not essential but play an important role in vegetative growth and in the initiation of differentiation.

4-Butyrolactone↗
PubMed2000

Insulin-degrading enzyme exists inside of rat liver peroxisomes and degrades oxidized proteins.

Insulin-degrading enzyme (IDE) was detected by immunoblot analysis in highly purified rat liver peroxisomes. IDE in the peroxisomal fraction was resistant to proteolysis by trypsin and chymotrypsin under conditions where the peroxisomal membranes remained intact. After sonication of the peroxisomal fraction, IDE was recovered in the supernatant fraction. Further, the localization of IDE in the peroxisomes was shown by immunoelectron microscopy. In addition, IDE isolated from peroxisomes degraded insulin as well as oxidized lysozyme as a model substrate for oxidized proteins. These results suggest that IDE exists in an active form in the matrix of rat liver peroxisomes and is involved in elimination of oxidized proteins in peroxisomes.

Animals↗
PubMed2000

Effects of oral administration of "rumen-bypass" vitamin D3 on vitamin D and calcium metabolism in periparturient cows.

Eleven late-pregnant Jersey cows were assigned to two groups; a group (PO-RBVD group) consisting of five cows treated with an oral administration of 10 million I.U. of an encapsulated form of vitamin D3 ("rumen-bypass" VD3; RBVD3) and another group (IMVD group) consisting of the other six treated with an intramuscular injection of 10 million I.U. of vitamin D3 (VD3). The cows received the RBVD3 or VD3 administration at 7 days before the expected parturition. The changes in the plasma concentrations of vitamin D metabolites, ionized Ca (Ca++) and inorganic phosphorus (iP) were evaluated. Of the vitamin D metabolites, the plasma 25-hydroxyvitamin D concentrations in PO-RBVD group increased significantly after the RBVD3 administration and remained in high levels that were significantly higher than those in IMVD group. This suggested that RBVD3 was absorbed rapidly and excellently from the post-ruminal digestive tract without the degradation by ruminal microorganisms. The plasma Ca++ and iP concentrations in PO-RBVD group tended to be higher after the administration and around parturition than those in IMVD group. From these observations, it was suggested the oral RBVD3 administration had more potent ability to prevent parturient paresis compared with the VD3 injection used widely in Japan.

Administration, Oral↗
PubMed2000

Serum KL-6 concentrations in dairy farmers.

STUDY OBJECTIVES: Serum KL-6 (Krebs von den Lungen-6) has been recognized to be a marker for the activity of diffuse interstitial lung diseases. The purpose of the study is to evaluate serum KL-6 measurement as a marker for farmer's lung disease (FLD). DESIGN: A cross-sectional survey of a cohort of dairy farmers. Retrospective measurement of KL-6 stored serum samples from those dairy farmers previously screened for FLD. SETTING: University hospital screening project for FLD within a dairy-farming community in Japan. PARTICIPANTS: Four hundred seventy-two dairy farmers were invited to attend a local clinic. MEASUREMENTS AND RESULTS: We examined serum KL-6 concentrations in 272 farmers. Subjects were classified into three groups: (1) 5 farmers with FLD, (2) 30 farmers with positive serum precipitating antibodies to Saccharopolyspora rectivirgula and/or Thermoactinomyces vulgaris without FLD (Ab(+)), and (3) 237 farmers without these antibodies (Ab(-)). Serum KL-6 concentrations in the FLD group were significantly higher than those in the Ab(+) and the Ab(-) groups (1,263 +/- 288 [SEM], 328 +/- 57, and 207 +/- 6 U/mL, respectively, p < 0.001). Serum KL-6 concentrations in those with FLD were significantly higher than KL-6 concentrations from stored screening samples from the same individual when FLD was not diagnosed (1,263 +/- 288 and 419 +/- 209 U/mL, respectively, p < 0.05). Serum KL-6 concentrations of the Ab(+) group were significantly higher than those of the Ab(-) group (p < 0.001). In the Ab(+) group, farmers with high serum KL-6 concentrations had lower permeability coefficients than farmers with normal serum KL-6 concentrations (p < 0.05). These results may suggest that subclinical FLD can be detected in farmers with high KL-6 concentrations and precipitating antibodies. CONCLUSION: Serum KL-6 concentration can be a useful marker for assessing the activity of FLD and may be able to be used to detect subclinical disease.

Actinomycetales↗
PubMed2000

[Evaluation of restenosis by serum levels of soluble Fas, Fas ligand and nuclear matrix protein before and after coronary intervention].

Serum levels of soluble Fas, soluble Fas ligand, and nuclear matrix protein (NMP) were measured in 38 patients with ischemic heart disease before and after coronary angiography or coronary intervention. Serum levels of soluble Fas, soluble Fas ligand and NMP were determined by enzyme-linked immunosorbent assay. Patients one week after undergoing stent implantation had much higher levels of soluble Fas ligand and significantly lower levels of soluble Fas than patients without coronary intervention. Serum levels of soluble Fas ligand and NMP in patients with coronary restenosis were significantly higher than those in patients without restenosis. Serum levels of soluble Fas and soluble Fas ligand in patients one week after undergoing stent implantation who had coronary restenosis were markedly lower and higher than in patients without restenosis, respectively. Serum levels of soluble Fas ligand were positively correlated with NMP in those patients. These results indicate that coronary restenosis might be affected by the Fas/Fas ligand system. We conclude that measurement of soluble Fas, soluble Fas ligand and NMP is useful for determination of coronary restenosis in patients with ischemic heart disease.

Angioplasty, Balloon, Coronary↗
PubMed2000

[The role of beta 2-adrenoceptor gene polymorphisms in asthma].

It has been reported that beta 2-adrenoceptor polymorphisms at nucleotide 46 (Arg16 to Gly) and nucleotide 79 (Gln27 to Glu) enhance and suppress receptor downregulation after prolonged exposure to a beta 2-agonist in vitro, respectively. To elucidate the role of these polymorphisms in bronchial asthma, the author studied the following three points: (1) the prevalence of these polymorphisms in the Japanese population, (2) whether these polymorphisms influence the clinical characteristics of asthma and (3) whether Arg16 to Gly polymorphism causes changes in baseline airway tone, methacholine airway responsiveness, and bronchoprotective and non-pulmonary effects of a beta 2-agonist after 2 weeks of regular, inhaled beta 2-agonist therapy in mild and moderate asthmatic patients. The allele frequencies of Gly16 and Glu27 in the Japanese healthy population were 0.49 and 0.09, respectively; both were significantly lower than those of Caucasians. The percentage of the Gly16/Gly genotype was significantly higher in moderate to severe asthma than in mild asthma (14.0 and 33.3%, respectively, p < 0.05). After regular inhaled salbutamol, a significant decrease of FEV1 (p < 0.05) and a significant increase of airway responsiveness (p < 0.02) were observed in the patients with Gly16/Gly. Although there were no significant changes in the bronchoprotective effect of salbutamol among the three genotypes, the increase in plasma cAMP induced by inhaled salbutamol was significantly attenuated in the patients with Gly16/Gly (p < 0.05). These results suggest a racial difference in the prevalence of beta 2-adrenoceptor polymorphisms that may be important modifiers of clinical characteristics of bronchial asthma.

Adrenergic beta-Agonists↗
PubMed2000

Comparison of endometrial carcinoma coexisting with and without endometrial hyperplasia.

OBJECTIVE: It has been reported that endometrial carcinoma has two pathogenic types; one with and the other without endometrial hyperplasia. The present study was done to clarify whether this was true in our series of a large number of Japanese patients. METHODS: Three hundred and twenty-eight patients with endometrial carcinoma were classified into two groups, one coexisting endometrial hyperplasia (group 1; 182 cases) and the other having normal endometrium without endometrial hyperplasia (group 2; 107 cases). The clinical and pathological observations of the two groups were compared. RESULTS: The ages of the patients were significantly lower in group 1 (30-83; mean 50.7) than in group 2 (34-81; mean, 57.2). The incidence of the carcinoma with invasion limited to less than 1/3 of the myometrium, with surgical stage I, lower grade endometrioid type and higher levels of progesterone receptor, and without lymph node metastasis were significantly higher in group 1 than in group 2. The cumulative survival rate for stage I was also significantly higher in group 1 patients. CONCLUSION: A significant difference was found between groups 1 and 2 in age distribution, degree of progress and pathological observations. Stage I patients in the former group had a better prognostic than the latter.

Adult↗
PubMed1999

Bacillus thuringiensis Cry1Aa toxin-binding region of Bombyx mori aminopeptidase N.

The Bacillus thuringiensis Cry1Aa toxin-binding region of Bombyx mori aminopeptidase N (APN) was analyzed, to better understand the molecular mechanism of susceptibility to the toxin and the development of resistance in insects. APN was digested with lysylendopeptidase and the ability of the resulting fragments to bind to Cry1Aa and 1Ac toxins was examined. The binding abilities of the two toxins to these fragments were different. The Cry1Aa toxin bound to the fragment containing 40-Asp to 313-Lys, suggesting that the Cry1Aa toxin-binding site is located in the region between 40-Asp and 313-Lys, while Cry1Ac toxin bound exclusively to mature APN. Next, recombinant APN of various lengths was expressed in Escherichia coli cells and its ability to bind to Cry1Aa toxin was examined. The results localized the Cry1Aa toxin binding to the region between 135-Ile and 198-Pro.

Amino Acid Sequence↗
PubMed1999

Neuroanatomic and functional correlates of depressed mood: the Cardiovascular Health Study.

Although a number of studies suggest an association between stroke and depression, few have examined the relation between magnetic resonance imaging (MRI)-identified lesions and depression among community-dwelling older adults. This cross-sectional study sought to assess the association between MRI infarcts in the basal ganglia and non-basal-ganglia areas, potential functional consequences of these lesions, and depressive symptomatology in 3,371 US men and women aged 65 years or older who participated in the Cardiovascular Health Study between 1992 and 1994. By using multiple linear regression models, the authors found that after adjustment for age, gender, and stroke history, Center for Epidemiologic Studies Depression Scale scores were independently associated with non-basal-ganglia lesions (p = 0.04) but were not independently associated with basal ganglia lesions (p = 0.11). When measures of physical disability and cognitive impairment were added to the models, these measures displaced MRI-identified infarcts in their association with depressive symptoms. In additional models, hemispheric location and size of the basal ganglia lesion were found to have no relation to depression levels. These results suggest that the functional consequences of cerebrovascular disease may be the causal pathway by which basal ganglia and non-basal-ganglia lesions are associated with depressive symptomatology.

Activities of Daily Living↗
PubMed1999

An ABC transporter homologous to TAP proteins.

Polymerase chain reaction amplification of cDNA from rat intestine revealed the expression of a novel ABC transporter, TAPL (TAP-like). Subsequently, the protein sequence was deduced from the nucleotide sequence of cDNA carrying the entire coding region. TAPL is transcribed ubiquitously in various rat tissues. The protein, with 762 amino acid residues, has potential transmembrane domains, and an ATP-binding domain in its amino and carboxyl terminal regions, respectively, and is highly homologous to TAP1 and TAP2 (transporters associated with antigen presentation/processing): pairwise comparisons with TAPL demonstrated 39 and 41% of the residues are identical, respectively. These numerical values are essentially the same as that for TAP1 and TAP2 (39%), and the hydropathy profiles of TAPL, TAP1 and TAP2 are quite similar. The similarity among these three proteins suggests that they could be derived from a common ancestral gene. Furthermore, we found that there is a potential splicing isoform, sharing the amino terminal 720 amino acid residues of TAPL.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Sterol regulatory element-binding protein negatively regulates microsomal triglyceride transfer protein gene transcription.

We herein report that mRNA expression of microsomal triglyceride transfer protein (MTP) and its protein synthesis decline in response to sterol depletion in HepG2 cells, and we functionally characterized the MTP gene promoter in an effort to investigate the molecular mechanisms by which MTP gene transcription is regulated. Luciferase assays using truncated versions of the reporter gene revealed that the region at -124 to +33 base pairs of the human promoter contains the elements required for the suppression of transcription by sterol depletion. Enforced expression of an active form of sterol regulatory element-binding protein (SREBP)-1 (amino acids 1-487) or -2 (amino acids 1-481), both of which are activated under sterol-depleted conditions, is able to mimic sterol-mediated down-regulation. Either further truncation of the promoter region or mutation of the putative SREBP-binding sequence (5'-GCAGCCCAC-3', -124 to -116 base pairs) abolishes the sterol- and SREBP-dependent transcriptional regulation. Gel mobility shift assay showed that recombinant SREBP-2-(1-481) is able to bind the sequence. Enforced expression of a truncated form of SREBP-2 (amino acids 31-481), which acts as an inhibitor of transcription of the low density lipoprotein receptor gene because it lacks the transcriptional activation domain, also diminishes the luciferase activity, suggesting that direct binding to the promoter region might be sufficient and that the mechanism by which SREBPs inhibit MTP gene expression is distinct from that for the transcriptional stimulation of sterol-regulated genes. Although the SREBP-binding site overlaps a negative insulin-responsive element, insulin negatively regulates MTP gene expression even when the amount of the active form of SREBPs is quite low under the sterol-loaded conditions, indicating that SREBPs only slightly mediate, if at all, the insulin effects. Overall, we conclude that SREBPs are responsible for regulation of lipoprotein secretion via their control of MTP gene expression. Moreover, our results describe for the first time a novel mechanism by which SREBPs negatively regulate expression of the gene encoding the protein involved in lipid metabolism.

Base Sequence↗
PubMed1999

Presence of phospholipid-neutral lipid complex structures in atherosclerotic lesions as detected by a novel monoclonal antibody.

A novel monoclonal antibody (ASH1a/256C) that recognizes atherosclerotic lesions in human and Watanabe heritable hyperlipidemic (WHHL) rabbit aortae is described. When (123)I-labeled ASH1a/256C antibody is injected intravenously into WHHL rabbits, it associates specifically with fatty streaks on the aorta. The antigen recognized by the antibody is lipid, based on extraction with chloroform and methanol from WHHL rabbit tissues. The antigen, purified by high performance liquid chromatography, was shown to be phosphatidylcholine (PC), which contains unsaturated fatty acyl groups based on analyses utilizing (1)H and (13)C nuclear magnetic resonance, Fourier transfer-infrared spectrum, and mass spectrometry. The antibody did not react with other classes of phospholipids or neutral lipids when tested using an enzyme-linked immunosorbent assay. When PC was mixed with either cholesterol, cholesteryl ester, or triacylglycerol, however, the reactivity of the antibody to PC increased up to 8-fold. Homogenates of aorta tissue obtained from normal and WHHL rabbits were fractionated using sucrose density gradient ultracentrifugation in which neutral lipid droplets, cellular membranes, and proteins are separated. The phospholipid content in cellular membrane fractions from WHHL rabbits was twice as high as that of normal rabbits, and there was an enormous difference in the antigenic activity in these fractions. The content of cholesterol in the cellular membrane fraction of WHHL rabbits was approximately 50 times higher than that of normal rabbits. Addition of neutral lipids to the cellular membrane fraction of normal rabbit markedly increased the antigenic activity. Atheromatous lesions in thickened WHHL rabbit aortic intima that were rich in lipid droplets were stained positively with ASH1a/256C immunohistochemically. These results strongly suggest that PC-neutral lipid complex domains are formed in atherosclerotic lesions.

Animals↗
PubMed1999

Bacillus thuringiensis insecticidal Cry1Aa toxin binds to a highly conserved region of aminopeptidase N in the host insect leading to its evolutionary success.

Bacillus thuringiensis insecticidal protein, Cry1Aa toxin, binds to a specific receptor in insect midguts and has insecticidal activity. Therefore, the structure of the receptor molecule is probably a key factor in determining the binding affinity of the toxin and insect susceptibility. The cDNA fragment (PX frg1) encoding the Cry1Aa toxin-binding region of an aminopeptidase N (APN) or an APN family protein from diamondback moth, Plutella xylostella midgut was cloned and sequenced. A comparison between the deduced amino acid sequence of PX frg1 and other insect APN sequences shows that Cry1Aa toxin binds to a highly conserved region of APN family protein. In this paper, we propose a model to explain the mechanism that causes B. thuringiensis evolutionary success and differing insect susceptibility to Cry1Aa toxin.

Amino Acid Sequence↗