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A Masuda

Publications and source records attributed to A Masuda.

At least 91 records · Page 5Linked to original sources
PubMed1998

cDNA cloning of a new member of the FTZ-F1 subfamily from a rainbow trout.

We describe here cDNA cloning of an orphan nuclear receptor family member, tFZR1, which has a FTZ-F1 box. The amino acid sequences of the zinc finger domain and the FTZ-F1 box has 92.8% and 100% identity, respectively, with those of zebrafish FTZ-F1. On the other hand, the overall homology between tFZR1 and zebrafish FTZ-F1 is low (33.0%). The results indicate that tFZR1 is a new member of fushitarazu factor 1 (FTZ-F1) subfamily.

Amino Acid Sequence↗
PubMed1998

Molecular cloning of human TAK1 and its mutational analysis in human lung cancer.

In previous reports, we described that DPC4/Smad4 and Smad2 are mutated in a fraction of human lung cancers and suggested possible roles of the downstream mediators of transforming growth factor-beta (TGF-beta)-elicited signals in the pathogenesis of this most common cancer. In the present study, we investigated whether another downstream mediator, human TGF-beta-activated kinase 1 (hTAK1), also is altered in lung cancer. For this purpose, the hTAK1 gene was cloned with the aid of an expression sequence tag database search and cDNA library screening, and hTAK1 was found to be expressed ubiquitously in 2 distinct isoforms regulated in a tissue-specific manner in fetal and adult normal tissues. Interestingly, hTAK1 was assigned to the chromosome region 6q14-21, which is deleted frequently in various human malignancies, including lung cancer. Despite our extensive search for alterations in 39 lung cancer specimens as well as in 16 lung cancer cell lines, somatic mutations of hTAK1 were not identified, indicating that hTAK1 itself is not a frequent target for genetic alterations in lung cancer.

Amino Acid Sequence↗
PubMed1998

Detection of antibodies to bovine viral diarrhoea virus (BVDV) and characterization of genomes of BVDV from Brazil.

An ELISA for the detection of antibodies to bovine viral diarrhea virus (BVDV) was developed based on antigens derived from a genotype I BVDV strain isolated in Switzerland. Using monoclonal antibodies we showed that this antigen contained the conserved non-structural protein NS3 whereas it essentially lacked the more strain-specific E2 surface glycoprotein. This ELISA has a sensitivity of 97.5% and a specificity of 99.2% as compared to the serum neutralization test (SNT). Preliminary experiments showed that this ELISA reliably detects antibodies to BVDV strains circulating in Brazil. Serum samples obtained from 430 adult cattle on 19 farms of the State of Rio Grande do Sul (Brazil) and one farm from Corrientes (Argentina) were tested for antibodies by means of this ELISA. We found antibodies in 56% +/- 15.1% of the cattle sera tested, which indicates that, in Brazil, the prevalence of infection with BVDV is similar to that found in Europe and the USA. Our sequence analysis of two BVDV isolates showed that BVDV of both genotypes I and II circulate in Brazil.

Animals↗
PubMed1998

Effects of the angiotensin converting enzyme inhibitor temocapril on insulin sensitivity and its effects on renal sodium handling and the pressor system in essential hypertensive patients.

The effects of the angiotensin converting enzyme (ACE) inhibitor temocapril on insulin sensitivity and its effects on renal sodium handling and the pressor system were investigated in essential hypertensive patients (EHT). Seven EHT were hospitalized and underwent a 2-h euglycemic hyperinsulinemic glucose clamp before and after 2 weeks' administration of temocapril (4 mg/day). Insulin sensitivity was calculated using the M value from the infusion rate of glucose with hyperinsulinemia using the glucose clamp method. Renal clearances of sodium, lithium, creatinine, and paraaminohippuric acid were used to calculate fractional proximal and distal tubular reabsorption of sodium (FPR(Na), FDR(Na)) and renal plasma flow (RPF) before and during insulin infusion by the glucose clamp method. Temocapril decreased blood pressure and increased M value significantly. Before temocapril treatment, hyperinsulinemia by the glucose clamp induced significant decreases of urinary excretion of sodium (U(Na) V) and fractional excretion of sodium (FENa). After treatment, these decreases were attenuated, and the change of U(Na) V (deltaU(Na) V) with hyperinsulinemia was significantly higher and deltaFENa showed a higher tendency, compared with before the treatment. FPR(Na) showed no change with hyperinsulinemia before treatment, but significantly decreased after treatment. DeltaFPR(Na) was significantly lower after treatment than that before treatment. FDR(Na) showed an increase with hyperinsulinemia, and deltaFDR(Na) was similar between before and after treatment. RPF showed no change with hyperinsulinemia, and no difference was found in deltaRPF between before and after treatment. Plasma norepinephrine level (PNE) and plasma renin activity (PRA) showed increases, whereas plasma aldosterone concentration (PAC) did not change with hyperinsulinemia. There were no significant differences in deltaPNE, deltaPRA, and deltaPAC between before and after treatment. From these results, it is suggested that in EHT 1) temocapril improves insulin resistance, and 2) although temocapril shows no significant influence on the augmentation of pressor systems by hyperinsulinemia, this agent attenuates the sodium-retaining action of hyperinsulinemia, which may be attributable to suppression of insulin-induced sodium reabsorption at the proximal tubules. These effects may lead to additional beneficial effects in the treatment of essential hypertensives with insulin resistance.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1998

Effects of aging on the insulin actions for the glucose metabolism and renal function in normotensives and essential hypertensives.

It has been suggested that hyperinsulinemia compensating insulin resistance in glucose metabolism may be a pathogenic factor in essential hypertension. On the other hand, age-associated increases in the prevalence of glucose intolerance and hypertension are also well established. The aim of this study is to clarify the influence of aging on insulin sensitivity in glucose metabolism and on renal sodium handling under hyperinsulinemia, which may relate to high blood pressure in insulin-resistant subjects. Fifty-two normotensive subjects and 61 patients with essential hypertension were evaluated in this study. The subjects of these groups were divided into young (<40 years old) and middle-elderly (> or = 40 years old): young normotensives (Y-NT, n = 22); middle-elderly normotensives (ME- NT, n = 30); young hypertensives (Y-HT, n = 9); and middle-elderly hypertensives (ME-HT, n = 52). Using the euglycemic hyperinsulinemic glucose clamp, insulin sensitivity was assessed as M value. Just before the start and the termination of the glucose clamp, creatinine clearance (Ccr) and urinary excretion of sodium (UNaV) were measured. In addition, renal plasma flow assessed as para-aminohippuric acid clearance was also measured at the same time in several subjects; 8 Y-NT, 8 ME-NT, 3 Y-HT, and 10 ME-HT. The M value was significantly lower in ME-NT, Y-HT, and ME-HT, compared to Y-NT, although blood sugar and immunoreactive insulin levels were similar in all four groups. In normotensive subjects, there was a significant, negative correlation between age and M value. However, this correlation was not observed in hypertensive patients. UNaV decreased in ME-NT, Y-HT, and ME-HT, but not in Y-NT under hyperinsulinemia by the glucose clamp, whereas Ccr showed no significant change in any group. In all subjects, the change of UNaV (deltaUNaV) correlated significantly and positively with the M value. Renal plasma flow significantly increased under hyperinsulinemia by the glucose clamp in only Y-HT, but not in the other groups. There was a significant, positive correlation between deltaUNaV and the change of renal plasma flow under hyperinsulinemia by the glucose clamp. These results suggested that both the impairments of the insulin sensitivity and insulin-induced vasodilation at the renal artery with aging may partially contribute to age-related elevation of blood pressure through renal sodium retention by compensating hyperinsulinemia. On the other hand, it seems reasonable to assume that these abnormalities, which can contribute to high blood pressure in essential hypertension, already may exist at lower ages in essential hypertensive patients.

Adolescent↗
PubMed1998

Spatially- and temporally-restricted expression of meltrin alpha (ADAM12) and beta (ADAM19) in mouse embryo.

The cloning of the full-length cDNA encoding meltrin beta (ADAM19), one of the metalloprotease-disintegrins expressed in mouse myogenic cells, revealed that the meltrin beta gene encodes a membrane protein closely related to meltrin alpha (ADAM12) which participates in myotube formation in vitro. To delineate the functions of meltrin alpha and beta, we examined the expression patterns of their transcripts during embryogenesis. The meltrin alpha gene is activated in condensed mesenchymal cells that give rise to skeletal muscle, bones and visceral organs. Meltrin beta mRNA, in contrast, is markedly expressed in craniofacial and dorsal root ganglia and ventral horns of the spinal cord, where peripheral neuronal cell lineages differentiate. Heart, skeletal muscle, intestine and lung also express meltrin beta mRNA transiently. Although the meltrin alpha and beta transcripts exhibit distinct expression patterns during embryogenesis, both genes are mainly activated in mesenchymal cells that are derived from both mesoderm and ectoderm.

ADAM Proteins↗
PubMed1998

Isolation of an aspartic proteinase precursor from the egg of a hard tick, Boophilus microplus.

An aspartic proteinase precursor, herein named BYC (Boophilus Yolk pro-Cathepsin) was isolated from eggs of the hard tick, Boophilus microplus. As judged by electrophoresis on sodium dodecyl sulfate polyacrylamide slab gel (SDS-PAGE), purified BYC presented 2 bands of 54 and 49 kDa, bearing the same NH2-terminal amino acid sequence. By Western blot analysis, BYC was also found in the haemolymph, indicating an extraovarian site of synthesis. Several organs were incubated in culture medium with [35S]methionine, and only the gut and fat body showed synthesis of BYC polypeptides. Protein sequencing of both the NH2-terminal and an internal sequence obtained after cyanogen bromide (CNBr) cleavage of BYC revealed homology with several aspartic proteinase precursors. Incubation at pH 3.5 resulted in autoproteolysis of BYC, which produced the mature form of the enzyme, that displayed pepstatin-sensitive hydrolytic activity against haemoglobin. Western blot analysis using anti-BYC monoclonal antibodies showed proteolytic processing of BYC during embryogenesis and suggested activation of the enzyme during development. A role of BYC in degradation of vitellin, the major yolk protein of tick eggs, is discussed.

Adipose Tissue↗
PubMed1998

Association of insulin resistance and hyperinsulinemia with disturbed lipid metabolism in patients with essential hypertension.

To clarify the association of insulin resistance and hyperinsulinemia with lipid metabolism in patients with essential hypertension (EHT), we used the euglycemic hyperinsulinemic glucose clamp technique (GC) and the 75-g oral glucose tolerance test (OGTT) to compare the characteristics of glucose and lipid metabolism in insulin-resistant patients with essential hypertension (EHT-R) with those in insulin-non-resistant patients with essential hypertension (EHT-N) and normotensive subjects (NT). Twenty-eight NT and 42 EHT whose body mass index (BMI) was less than 28 kg/m2 were studied to eliminate the effects of obesity on insulin sensitivity and lipid metabolism. Insulin sensitivity was evaluated by GC and expressed as metabolic clearance rate of glucose (M value, mg/m2/min). Mean -ISD of the M value in NT (145.0 mg/m2/min) was chosen as the cutoff point for insulin resistance. On the basis of this value, 33.3% of the EHT were EHT-R. There was no significant difference in age or BMI among the three groups. Blood samples were collected before GC to measure levels of total cholesterol (TC), triglyceride (TG), free fatty acid (FFA), and HDL cholesterol (HDL-C). EHT-R had significantly higher levels of fasting blood sugar, fasting immunoreactive insulin, insulin at 120 min (IRI-120), and summation of insulin or blood sugar (BS) during the OGTT, as compared with NT and EHT-N. EHT-R also had significantly higher FFA and TG than the other two groups, while there was no difference in FFA or TG between EHT-N and NT. TC and HDL-C were similar in the three groups. There was either a significant negative correlation, or a trend toward negative correlation, between M value and FFA (r= -0.50, p < 0.05) or TG (r= -0.24, p < 0.1). There were significant positive correlations between IRI-120 and FFA (r=0.35, p< 0.05) or TG (r=0.29, p< 0.05). There was a positive correlation (r= -0.36, p< 0.01) between sigma BS and FFA, while no other significant relation was found between sigma BS and serum lipids. In summary, (i) 33.3% of EHT were found to be insulin resistant, when insulin resistance was defined as M value < 145.0 mg/m2/min, i.e., mean -ISD of the M value of NT; (ii) these EHT-R had higher levels of BS, insulin, FFA, and TG than did NT and EHT-N; (iii) EHT-N showed no difference in the levels of BS, insulin, or lipid, as compared with NT; and (iv) the levels of FFA and of TG correlated negatively with insulin sensitivity and positively with the insulin level during the OGTT. These results suggest that disturbances of glucose and lipid metabolism in EHT may be related to both insulin resistance and compensatory hyperinsulinemia, and that EHT-R may have more risk factors for arteriosclerotic complications than EHT-N.

Blood Glucose↗
PubMed1998

A new aspect of the carotid body function controlling hypoxic ventilatory decline in humans.

Ventilatory response to eucapnic sustained mild hypoxia was measured in one patient with unilateral and three patients with bilateral carotid body (CB) resection (defined UR and BR, respectively). The profile of ventilatory response in UR patient was initially augmented then gradually declined (biphasic pattern) as generally seen in normal subjects although the absolute magnitude was substantially low. On the other hand, biphasic pattern was disappeared in all three BRs. Lack of hypoxic ventilatory decline (HVD) in the late period of sustained hypoxia was in marked contrast to that reported in the anaesthetized and CB-denervated animals whose ventilation was severely depressed lower than the pre-hypoxic control level. In view of recent knowledge that the analogous mild hypoxia in normal animals and humans elicits an useful adaptation to economize energy expenditure with maintaining reversible excitability in control of respiration, BR patients were considered to have lost this ability. We conclude that in awake humans the CB not only stimulates ventilation but also controls the degree of subsequent HVD during sustained hypoxia.

Adaptation, Physiological↗
PubMed1998

Cardiovascular change in elderly male breath-hold divers (Ama) and their socio-economical background at Chikura in Japan.

The Ama have existed for more than 2000 years in Japan and Korea. They have been diving for seaweed and molluscs. Their traditional way of fishing, with goggles or a mask, but without a wetsuit, is still practised as a result of laws against overfishing. We investigated cardiovascular diving responses, expressed as heart rate (HR) reduction, peripheral vasoconstriction indicated by skin blood flow (SkBF) and mean arterial blood pressure (MAP) during breath-hold face immersion in a group of eight elderly male Ama at Chikura, Japan. Their data were compared to those from three other groups: a) elderly non-divers; b) young divers and c) young non-divers. Our previous studies have shown that young divers show a more pronounced bradycardia than young non-divers. The present study of elderly Ama and elderly non-divers was performed to investigate if this difference persists in old age. We found that, in spite of many years of diving experience, HR reduction of the elderly professional divers observed during face immersion did not differ from that of elderly non-divers, but it was much less pronounced than in the two younger groups. We conclude that even if a well-developed diving response at young age has been reduced to the level of non-divers, the Ama are still able to continue their work of diving in old age. Ama that has been a traditionally female occupation, is mostly practised by men at Chikura today. No young have been recruited for this profession. Therefore, the present Ama are senior and the traditional breath-hold diving will probably cease to exist in the near future. The probable reasons for these changes are discussed.

Adaptation, Physiological↗
PubMed1998

Dynamic viscoelastic properties in torsion of four commercially available resins for crown and bridge.

In order to clarify the viscoelastic properties of four commercial resins for crown and bridge, the dynamic shear modulus (G'), Knoop hardness (KHN), filler content, quantity of unreacted substance and thermal expansion were measured. The results were as follows. The G' (37 degrees C) of each material ranged from 2.61-11.1 GPa, and gradually decreased with increasing temperature. KHN (23 degrees C) ranged from 29.4 to 120, and the most significant correlation (0.999) was found between G' and KHN. Of the relationship among G', filler content and unreacted substance, there was a highly significant correlation (0.980) between G' and filler content. The coefficient of linear-thermal expansion (alpha) also ranged from 17.9-65.0 x 10(-6)/degree C (25-60 degrees C), and the correlation (-0.961) between G' and alpha was meaningful. It can be presumed that the temperature dependence of G' is closely connected with the specific volume of each material, together with an increase in temperature.

Composite Resins↗
PubMed1998

[Efficacy of epidural analgesia in minimally invasive direct coronary artery bypass surgery].

Minimally invasive direct coronary artery bypass surgery (MIDCAB), coronary bypass grafting with small thoracotomy using no cardiopulmonary bypass (CPB), became popular recently. To attenuate perioperative stress-response, we used epidural analgesia (EPI) with general anesthesia for MIDCAB operation. In this study, we compared retrospectively 11 cases of MIDCAB managed with EPI [ED (+)], and 14 cases of MIDCAB anesthetized without using EPI [ED (-)], concerning extubation time, ICU stay, hospital stay and perioperative complications. The mean time from cessation of general anesthesia to extubation was significantly shorter in ED (+) patients (0.5 hours) when compared to ED (-) patients (18.2 hours). Mean periods of ICU stay and hospital stay were, also, shorter in ED (+) patients (2.1 days, 30.5 days, respectively) when compared to ED (-) (4.3 days, 45.1 days, respectively) patients. We experienced ventricular tachycardia in three patients of ED (-). No major complication occurred in ED (+) patients. These results suggest that EPI shortened extubation time, ICU and hospital stay for MIDCAB patients.

Aged↗
PubMed1997

Establishment of human peripheral lung epithelial cell lines (HPL1) retaining differentiated characteristics and responsiveness to epidermal growth factor, hepatocyte growth factor, and transforming growth factor beta1.

Novel human epithelial cell lines retaining characteristic features of normal peripheral airway cells were established by transfecting the SV40 large T antigen gene into primary in vitro outgrowths from normal peripheral lung specimens. These lines, designated as HPL1A to HPL1E, showed the polygonal shapes typical of epithelial cells and expressed cytokeratin in abundance. Ultrastructural examination revealed the presence of microvilli, multivesicular bodies, and multilamellar body-like structures that are characteristic of type II pneumocytes, but expression of CC1O transcripts, a highly specific marker for Clara cells, was also observed. Response to transforming growth factor beta, epidermal growth factor (EGF), and hepatocyte growth factor, all of which are thought to be important growth-regulatory molecules for cellular proliferation and developmental processes of peripheral lung, was apparent. In the HPL1A case, markedly altered cell morphology and cytoskeletal organization, potent inhibition of cell growth, and increased expression of an extracellular matrix protein were noted with transforming growth factor beta. Interestingly, both EGF and hepatocyte growth factor stimulated anchorage-dependent growth, whereas only EGF could sustain anchorage-independent proliferation. The HPL1 lines are, to our knowledge, the first series of stable epithelial lines of human peripheral lung to be described. They should be valuable for investigating various aspects of growth regulation and oncogenic processes, including the mechanisms of acquisition of anchorage independence and the interrelationships of genetic changes identified previously in lung cancers. In addition, the HPL1 lines may also prove useful for development of in vitro models for other human lung disorders as well as to elucidate the mechanisms of peripheral lung differentiation.

Aged↗
PubMed1997

Sequential observation of micrometastasis formation by bacterial lacZ gene-tagged Lewis lung carcinoma cells.

Sequential events in micrometastasis formation including entry into the blood circulation and arrest, extravasation and initial growth in the lung was investigated using bacterial lacZ gene-tagged Lewis lung carcinoma cells (4A1-1). Micrometastases in the lung could thereby be specifically detected at the single cell level by X-Gal staining. After intravenous injection, X-Gal positive tumor cells appeared to extravasate within hours, but most cells then degenerated or died in the alveolar space by 2-3 days postinjection. A decreased BrdU labeling index to a negligible level at 2 days postinjection and reduction of X-Gal positive foci to a basal level (less than 0.1% of injected cells) by 4 days are in line with rapid clearance of tumor cells from the lung. The size and BrdU labeling indices of the persisting X-Gal positive foci, however, started to increase from 4 days postinjection. Type IV collagen immunostaining demonstrated loss of pre-existing basement membranes with growth of micrometastases: When 4A1-1 cells were inoculated subcutaneously, lung micrometastases from resulting tumors were detected as single or small numbers of X-Gal positive cells at 2 weeks postinjection. Progressive development of micrometastasis to macroscopic metastasis was noted by 4-5 weeks postinjection. The results indicate that micrometastasis formation by Lewis lung carcinoma cells involves a sequence of events starting with rapid extravasation after arrest in the lung within 1 day, followed by death of most cells at 2-3 days and subsequent new growth and expansion of persisting tumor cells from 4 days postinjection.

Animals↗
PubMed1997

Reconstitution of bacteriorhodopsin from a mixture of a proteinase V8 fragment and two synthetic peptides.

The peptide and retinal mixture of bacteriorhodopsin, composed of two synthetic peptides corresponding to helices F (160-197) and G (202-237) and a proteinase V8-derived fragment V1 (1-166), generated the characteristic features of bacteriorhodopsin with absorbance maximum at 550 nm and fluorescence quenching as in two synthetic peptides corresponded to helix A (sequence 7-31) and B (41-65) and a chymotryptic fragment (72-248). The recovery of reconstitution estimated from the absorption and the fluorescence quenching of these mixture was 16-19% and 25-32% of the native purple membrane, respectively, whereas mixtures lacking any one of the peptides exhibited no absorption recovery Circular dichroism of each peptide fragment showed complete formation of alpha-helical structure in a membrane-mimetic medium of sodium dodecyl sulfate. These results indicate that the specific interactions or mutual recognitions between alpha-helices in lipid bilayers are essential for correct bundling of the seven helices and formation of the retinal binding pocket.

Amino Acid Sequence↗