Search PubMed⌕ Search

Biomedical subjects

T Sekiguchi

Publications and source records attributed to T Sekiguchi.

At least 163 records · Page 9Linked to original sources
PubMed1986

Reliability of non-invasive estimates of pulmonary hypertension by pulsed Doppler echocardiography.

The duration of the acceleration phase of pulmonary systolic flow was measured by pulsed Doppler echocardiography in 39 normal subjects and 67 patients with heart disease to evaluate the reliability of this Doppler index as an estimate of pulmonary arterial pressure. The mean (SD) Doppler index in patients with abnormal mean pulmonary arterial pressure (greater than 15 mm Hg) was significantly shorter than that in normal subjects (110 (30) ms vs 150 (10) ms). The Doppler index was significantly related to the mean pulmonary arterial pressure (r = -0.75) the pulmonary blood flow (r = 0.46), and the total pulmonary vascular resistance (r = -0.68). Forty four of 45 patients with an abnormal index (less than or equal to 120 ms) showed abnormal mean pressure (greater than 15 mm Hg). Without exception patients with a low index (less than or equal to 90 ms) had distinct pulmonary hypertension (greater than or equal to 25 mm Hg). Twelve of 22 patients with a normal index (greater than or equal to 130 ms), however, also showed abnormal pressures. Nine of the 12 had an atrial septal defect and they had high pulmonary arterial pressure associated with high blood flow. Eighteen patients with valvar heart disease, whose mean pulmonary arterial pressure ranged from 16 mm Hg to 24 mm Hg, had a significantly shorter acceleration phase and a higher total vascular resistance than 11 patients with atrial septal defect in whom the pressure range was similar (120(20) ms vs 140 (20) ms, 3.8 (1.1) hybrid resistance unit vs 1.6 (0.5)). Thus although the acceleration time of the pulmonary systolic flow is useful for the evaluation of pulmonary hypertension, it is a complex index that is affected not only by pulmonary arterial pressure but also by pulmonary blood flow and pathological changes in the pulmonary vascular bed.

Adult↗
PubMed1986

[Effects of cisapride on lower esophageal sphincter pressure and gastroduodenal motor activity in man].

Manometric study was performed to investigate the effects of cisapride, a new non-antidopaminergic gastrointestinal prokinetic compound, on interdigestive lower esophageal sphincter pressure (LESP) and gastroduodenal motility using infused catheter technique. The subjects consisted of 9 healthy volunteers and 29 patients with progressive systemic sclerosis (19), reflux esophagitis (8) and others (2). 4 mg of cisapride was given by bolus injection, continuous infusion or oral administration. The following results were obtained: Intravenous and oral cisapride increased LESP compared with basal pressure. Especially, bolus injection of cisapride caused a significant elevation of LESP during 30 minutes after administration. After administration of cisapride, gastroduodenal motility was accelerated gradually, then inducing IMC-like contractions. By bolus injection, IMC-like contractions were induced in healthy subjects more frequently than in patients group. On the other hand, motility index of stomach and duodenum showed persistent increase in patients group compared with healthy subjects. Cisapride-induced IMC-like contractions initiated from LES and upper part of stomach and mediated to duodenum, though aborad migration was not confirmed in the present study.

Adolescent↗
PubMed1986

Structure of HTLV and its biological function in leukemogenesis of adult T-cell leukemia.

There is a high homology of nucleotide sequence between 3' two-thirds of the X (or pX) regions of human T-cell leukemia virus (HTLV)-I, and of HTLV-II. Monoclonal antibody against p41 coded from X-IV, an open reading frame of X region of HTLV-I, was established. Two proteins coded by Xb, one of the open reading frames in X region of HTLV-II, were newly identified as p24 and p26. The expression of X protein of HTLV-II in the reconstituted mouse embryonal carcinoma cell line, which shows myoblastic morphology, reverted the morphology to that of the original embryonal carcinoma cells. This suggests that the function of X protein is to disturb the regulation of cell lineage determination. Leukemogenesis of adult T-cell leukemia (ATL) is also considered to consist of multisteps, in which HTLV-I constitutes one step, other factors also being involved. Even the role of HTLV-I factor could be similarly played by other factor(s). In agreement with this hypothesis, there are patients with ATL without associated HTLV-I.

Adult↗
PubMed1986

Blood levels and distribution of talampicillin and bacampicillin in NZW rabbits.

Parameters for blood concentrations of the peroral antibiotics talampicil in and bacampicillin, in NZW rabbits were determined using a two compartment model. On the basis of these pharmacokinetic parameters, a three compartment model was prepared for the concentrations of these drugs in the tongue, gingiva, submandibular gland, parotid gland, cervical lymph-node and mandibular bone. Simulation curves based on the parameters of tissue concentrations revealed visual conformity to the measured values.

Ampicillin↗
PubMed1985

Histone expressions in mouse-rat somatic reconstituted cells.

A critical analysis of histone expression was performed on the four interspecific and the two intraspecific reconstituted cells formed between karyoplast from mouse B16 cells and the cytoplast from rat cells (L6TG.CAPr) or mouse cells (B82.CAPr). All the reconstituted cells had the same pattern of mouse histones and the same amount of mouse-specific H2B. 2 histone as that of mouse nuclear donor cells. A hybrid between B16 and L6TG.CAPr contained both mouse and rat-specific H1b subtypes, whereas no rat-specific H1b was detected in the interspecific reconstituted cells. In both intra- and interspecific reconstituted cells, the proportion of H1b content was lower than that of B16 cells but that of H1 degree was higher, indicating that the mouse H1 patterns from these cells slightly resembled the pattern of slower growing and differentiated cytoplast donor cells. As an effect of the tumor promoter, the H1 pattern tended to revert to that of the nuclear donor cells in agreement with the phenotypic reversion, without any significant change in cell growth.

Animals↗
PubMed1985

Pleiotropic phenotypic expression in cybrids derived from mouse teratocarcinoma cells fused with rat myoblast cytoplasts.

Cybrid clones were isolated by fusing mouse embryonal carcinoma (PCC4) cells with cytoplasts of rat myoblastic cells (L6TG X CAPr). Although some clones were similar to PCC4 (Type II), a high proportion (88%) were differentiated; the differentiated cells had a mesh-like arrangement (Type I) or were flat with many projections (Type III). Protein patterns of both Type I and Type III cells changed markedly from that of PCC4 cells. Type III cells lacked alkaline phosphatase and expressed endo A and B proteins predominantly. One Type III clone produced alpha-fetoprotein and plasminogen activator (visceral endoderm-like), while another clone consisted of trophectodermal cell-like giant cells. Therefore it was shown that introduction of the somatic cell cytoplasm induces differentiation of teratocarcinoma stem cells, suggesting a cytoplasmic element (or elements) regulating gene expression.

Alkaline Phosphatase↗
PubMed1985

Partial purification and characterization of type I DNA topoisomerase from Bacillus stearothermophilus.

Type I DNA topoisomerase was partially purified from Bacillus stearothermophilus by ammonium sulfate precipitation and column chromatographies on phosphocellulose, DEAE-cellulose and heparin-agarose. On heparin-agarose chromatography, topoisomerase I activity was separated into three fractions (designated Fractions A, B, and C). Each fraction was further subjected to gel filtration on Sephacryl S-200. From electrophoretic analysis on polyacrylamide gel, Fraction A was found to contain two enzyme species having molecular weights of 110,000 and 100,000, and Fraction B one enzyme species with a molecular weight of 80,000. The molecular weight of the enzyme in Fraction C was estimated to be around 150,000 by gel filtration. The enzymes in Fractions A and B exhibited little activity in the presence of Mg2+, while the activity was increased remarkably by NaCl with Mg2+. No activity was observed in the presence of NaCl alone. The enzyme in Fraction C required only Mg2+ for full activity. With Fraction A, the topoisomerase I-induced cleavage sites on tetracycline-resistant plasmid pNS1 (2.55 megadaltons) were mapped. Fraction A cleaved the DNA at ten specific sites. These sites were compared to those of the Haemophilus gallinarum enzyme, which have already been mapped (Shishido et al. (1983) Biochem. Biophys. Acta 740, 108). The results showed that there is a remarkably coincidence between the cleavage sites induced by the B. stearothermophilus and H. gallinarum enzymes.

Binding Sites↗
PubMed1985

[Laboratory and clinical studies on cefminox in the pediatric field].

Laboratory and clinical studies were performed as follows on cefminox (CMNX, MT-141), a new cephamycin antibiotic. Pharmacokinetics Serum concentrations of CMNX were measured in 4 patients given CMNX for prophylactic purpose during cardiac catheterization. In 2 patients given 20 mg/kg of CMNX by intravenous bolus injection, the average of peak serum concentration was 178.9 micrograms/ml at 15 minutes. The mean urinary recoveries in these 2 cases was 66.9% within 6 hours after injection. In 2 patients given 20 mg/kg of this drug by 1 hour drip infusion, the peak serum concentration was obtained at the time drip was completed, and the average value was 68.3 micrograms/ml. Clinical efficacy CMNX was administrated intravenously to 13 patients in dose of 52.9 approximately 96.0 mg/kg t.i.d. or q.i.d. for 4 approximately 7 days; 3 with tonsillitis, 6 with bronchitis, 1 with bronchopneumonia, 1 with UTI, 1 with lymphadenitis and 1 with enterocolitis. The overall efficacy rate was 92.3%, i.e., efficacy was excellent in 12, and poor in 1. Bacteriological efficacy was excellent, i.e., 3 of 3 strains disappeared. Side effects were observed in 3 cases, i.e., 1 case of eruption, 1 case of diarrhea and 1 case of transient eosinophilia. The above results suggest that CMNX is a useful antibiotic for treating pediatric bacterial infections.

Anti-Bacterial Agents↗
PubMed1985

[Clinical evaluation of lenampicillin in oral and maxillofacial infections].

Clinical efficacies of newly developed synthetic oral ampicillin prodrug lenampicillin (LAPC, KBT-1585) applied to 109 cases of oral infection were studied. There were 7 dropout cases. The results as determined on a point system are as follow: Remarkably effective, 26 cases; effective, 63 cases; and not effective, 13 cases, for an efficacy rate of 87.3%. When rated by the subjective judgement of the doctors in charge, these figures are as follow: remarkably effective, 21 cases, effective, 67 cases; slightly effective, 10 cases; and not effective, 4 cases. The rate of efficacy in this way being 86.3%. In either way, the results obtained were favorable. Among 102 cases in this study, pus was aspirated with sterile needle from obstructed abscesses in 65 cases, with the result that 161 strains of bacteria were isolated and identified. Most of infections were found mixed type by aerobic Gram-positive cocci and anaerobes. Especially, cases caused by alpha-Streptococcus were observed in 48 out of 55 mixed infective cases. LAPC's MIC distribution against the detected bacteria showed strong antibacterial effect as follows: against Gram-positive cocci, less than 0.39 micrograms/ml; against Gram-negative bacteria (excluding some insusceptible strains), less than 3.13 micrograms/ml. Thus, LAPC demonstrated a superiority when compared to CEX by 4 approximately 128-fold, and when compared to AMPC by about 2-fold. Adverse reactions among the 109 cases consisted of 6 cases of gastro-intestinal disorders including 3 cases of diarrhea. Recognized cases of abnormal laboratory findings were 3 cases out of 76 (3.9%), but none were serious.

Administration, Oral↗
PubMed1984

Cloning of beta-isopropylmalate dehydrogenase gene from Bacillus coagulans in Escherichia coli and purification and properties of the enzyme.

The beta-isopropylmalate dehydrogenase (2-hydroxy-4-methyl-3-carboxyvalerate: NAD+ oxidoreductase, EC 1.1.1.85) gene from Baccilus coagulans was cloned and expressed in Escherichia coli C600, using pBR322 as a vector plasmid. The B. coagulans enzyme was purified to a homogeneous state from the E. coli carrying a pBR322 - the B. coaglulans enzyme gene hybrid plasmid. The enzyme consists of two subunits of equal molecular weight (4.4 X 10(4) ). The enzyme activity was stimulated by 0.5 mM Mn2+, Mg2+ and Co2+. The enzyme was strongly inhibited by 0.2 mM p-chloromercuribenzoate and the inhibition was completely recovered by 1 mM dithiothreitol. The B. coagulans enzyme was thermostabilized by 1.5 M NaCl. The B. coagulans enzyme is a composite of alpha-helix, beta-sheet and remainder. The secondary structure of the enzyme was appreciably altered by 0.5 mM MgCl2 and 1.5 M NaCl.

3-Isopropylmalate Dehydrogenase↗
PubMed1984

Isolation and characterization of intraspecific cybrids. Effect of mitochondrial DNA on their cellular properties.

Cybrid clones were obtained by fusing whole cells of rat glioma C6BU-1, resistant to 5-bromodeoxyuridine (BrdU), with cytoplasts of embryonic rat 3Y1CAP cells, resistant to chloramphenicol (CAP), in selective medium with BrdU and CAP. The clones resistant to BrdU and CAP were confirmed to be cybrids by chromosome and mtDNA analyses. More than half the mtDNA of all the cybrid clones was from the 3Y1CAP cells. After cultivation of a cybrid clone Y22 for 3 months in the absence of CAP, subclones were isolated. One subclone Y22-22 contained predominantly mitochondrial DNA (mtDNA) from the 3Y1CAP cells. Using this subclone, the effects of the mitochondrial genome on cellular properties were examined. The growth patterns, expression of glioma-specific beta-adrenergic receptor, and composition of the major proteins of C6BU-1 cells were not affected by transmitted mtDNA from the 3Y1CAP cells. This procedure for isolating cells containing predominantly foreign mtDNA will be useful in studies on the interaction between genomes of the mitochondria and nucleus.

Animals↗
PubMed1984

Correction of sister chromatid exchanges in Bloom's syndrome fibroblasts after fusion with cytoplasts from a Chinese hamster cell line.

Cytoplasmic hybrids (cybrids) were prepared by fusion of Bloom's syndrome (BS) fibroblasts with cytoplasts derived from a chloramphenicol (CAP)-resistant cell line of hypoxanthine phosphoribosyl transferase (HPRT)-deficient Chinese hamster wg3h cells to study the role of cytoplasmic and nuclear factors which may involve corrective factor(s) of sister chromatid exchanges (SCEs) of the BS cells. The high rate of SCEs characteristic of the cultured BS fibroblasts was found to be fully corrected in cybrids. This result suggests the existence of a transmissible corrective factor(s) in the cytoplasm of the Chinese hamster cells. Long-term cultures of such cybrids after 3 and 5 weeks of fusion, however, showed a reversion to a high SCE level similar to the parental BS cells, indicating that the corrective factors have not been stable in the cybrid cells.

Animals↗