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Biomedical subjects

M Takano

Publications and source records attributed to M Takano.

At least 415 records · Page 23Linked to original sources
PubMed1985

H+ gradient-dependent transport of aminocephalosporins in rat renal brush border membrane vesicles: role of H+/organic cation antiport system.

The transport of aminocephalosporin antibiotics such as cephalexin, zwitterion, by rat renal brush border membrane vesicles has been studied in relation to the transport system of organic cation. Cephalexin uptake was inhibited by organic cations such as tetraethylammonium, 1N-methylnicotinamide and choline, whereas cefazolin uptake was not. Tetraethylammonium uptake was inhibited by aminocephalosporins and stimulated by the countertransport effect of cephalexin. In agreement with the transport mechanisms of organic cation, the presence of an H+ gradient ([H+]i greater than [H+]o) induced a marked stimulation of aminocephalosporin uptake, and this uptake was inhibited by HgCl2 and tetraethylammonium. These results suggest that aminocephalosporins can share a common carrier transport system with organic cation in renal brush border membranes, and this system could be a part of the mechanisms of tubular secretion for aminocephalosporins.

Animals↗
PubMed1985

Structure of the pX protein deduced from the nucleotide sequence of a cDNA clone of pX mRNA in cells infected with human T-cell leukemia virus type I.

A splice donor site of pX mRNA of human T-cell leukemia virus type I was elucidated by analyzing a cDNA clone of poly A+ RNA isolated from cat fibroblast cells infected with the virus. The donor site was located near the 5' end of the env gene. The putative N-terminal amino acid sequence of the pX protein was deduced to be Met-Ala-His---.

Amino Acid Sequence↗
PubMed1985

Transport of p-aminohippurate, tetraethylammonium and D-glucose in renal brush border membranes from rats with acute renal failure.

Transport of D-glucose, p-aminohippurate and tetraethylammonium has been studied using renal brush border membrane vesicles isolated from rats with uranyl nitrate-induced acute renal failure (ARF). Initial rate and overshoot magnitude of Na+ gradient-dependent D-glucose uptake were decreased in brush border membrane vesicles from ARF rats compared with normal rats, although there was no significant difference on D-glucose uptake in the presence of equilibrated Na+ between normal and ARF rats. Uptake of p-aminohippurate by membrane vesicles from ARF rats did not differ from normal membrane vesicles. Uptake of tetraethylammonium with or without an H+ gradient was decreased in membrane vesicles from ARF rats compared with normal rats. Dissipation rate of H+ gradient across brush border membranes did not differ between both groups. In vitro incubation of normal brush border membrane vesicles with uranyl nitrate caused no alteration in any substrate transport. However, enzyme activities such as (Na+ + K+)-adenosine triphosphatase in renal cortical homogenate were inhibited markedly in the presence of uranyl nitrate. These results suggest that uranyl nitrate-induced ARF caused alterations in the transport properties of renal brush border membranes and that these transport dysfunctions were not due to the direct effect of uranyl nitrate, but could be secondarily induced after the impairment of the integrity for tubular cells.

Acute Kidney Injury↗
PubMed1985

[Abnormal left ventricular endocardial structures detected by two-dimensional echocardiography in systemic lupus erythematosus].

This is a report of abnormal endocardial structures on the left ventricular wall as visualized by two-dimensional echocardiography (2-D echo) in patients with systemic lupus erythematosus. Abnormal endocardial structures, arising from the left ventricular endocardium and appearing to proliferate into the cavity, were found in 11 (20%) of 54 patients. The most frequently involved site was posterobasal left ventricular wall in the parasternal long-axis view, and the posterolateral segment of the left ventricle including the anterior and posterior papillary muscles in the parasternal short-axis view. M-mode echocardiograms, simultaneously recorded with 2-D echo, revealed abnormal structures of increased intensity adjacent to the endocardium with thicknesses of 4 approximately 7 mm. Most of the abnormal endocardial structures were observed in patients in the active phase by 2-D echo, and they appeared to regress with steroid therapy. In one autopsy case, fibrous endocardial thickening suggesting healed endocarditis was present in the anterior papillary muscle as observed by 2-D echo. Their location and response to steroid therapy suggests that these abnormal echoes could represent Libman-Sacks endocarditis.

Adult↗
PubMed1985

[Clinical experience with cefmenoxime (CMX) in complicated urinary tract infections].

Cefmenoxime (CMX) was intravenously administered to 106 patients with complicated urinary tract infection at a daily dose of 2-4 g for 5 days. An excellent response in overall clinical efficacy was seen in 15 cases (18.3%), a moderate response in 46 cases (56.1%) and poor response in 21 cases (25.6%). Pyuria was cleared in 20 cases (24.4%), decreased in 22 cases (26.8%) and unchanged in 40 cases (48.8%). Bacteriuria was eliminated in 41 cases (50.0%), decreased in 17 cases (20.7%), relapsed in 7 cases (8.5%) and unchanged in 17 cases (20.7%). Bacteriologically, 74 (76.8%) of the 95 strains isolated were eradicated by CMX, and 22 (23.2%) persisted. Side effects were observed in 3 (abdominal pain, diarrhea and elevation of trans amylase) of the 106 cases. Judging from the above results, CMX is considered to be a useful drug in the treatment of complicated urinary tract infections.

Adolescent↗
PubMed1984

Carrier-mediated transport systems of tetraethylammonium in rat renal brush-border and basolateral membrane vesicles.

Transport of [3H]tetraethylammonium, an organic cation, has been studied in brush-border and basolateral membrane vesicles isolated from rat kidney cortex. Some characteristics of carrier-mediated transport for tetraethylammonium were demonstrated in brush-border and basolateral membrane vesicles; the uptake was saturable, was stimulated by the countertransport effect, and showed discontinuity in an Arrhenius plot. In brush-border membrane vesicles, the presence of an H+ gradient ( [H+]i greater than [H+]o) induced a marked stimulation of tetraethylammonium uptake against its concentration gradient (overshoot phenomenon), and this concentrative uptake was completely inhibited by HgCl2. In contrast, the uptake of tetraethylammonium by basolateral membrane vesicles was unaffected by an H+ gradient. Tetraethylammonium uptake by basolateral membrane vesicles was significantly stimulated by a valinomycin-induced inside-negative membrane potential, while no effect of membrane potential was observed in brush-border membrane vesicles. These results suggest that tetraethylammonium transport across brush-border membranes is driven by an H+ gradient via an electroneutral H+-tetraethylammonium antiport system, and that tetraethylammonium is transported across basolateral membranes via a carrier-mediated system and this process is stimulated by an inside-negative membrane potential.

Animals↗
PubMed1984

Carrier-mediated transport of cephalexin via the dipeptide transport system in rat renal brush-border membrane vesicles.

Carrier-mediated transport of aminocephalosporin antibiotics by renal brush-border membrane vesicles has been studied in relation to the transport systems for dipeptides and amino acids. Dipeptides such as L-carnosine (beta-alanyl-L-histidine) and L-phenylalanylglycine competitively inhibited the uptake of cephalexin, but amino acids did not. Cephalexin uptake was stimulated by the countertransport effect of L-carnosine in the normal and papain-treated vesicles, and by the effect of L-phenylalanylglycine only in the papain-treated vesicles. In the papain-treated vesicles, the hydrolysis of dipeptides was markedly decreased, and the specific activity for cephalexin transport was increased approx. 2-fold because of the partial removal of membrane proteins. These results suggest that carrier-mediated transport of cephalexin can be transported by the system for dipeptides in renal brush-border membranes.

Amino Acids↗
PubMed1984

Enzyme activities and sodium-dependent active D-glucose transport in apical membrane vesicles isolated from kidney epithelial cell line (LLC-PK1).

Apical membrane vesicles were isolated from the confluent LLC-PK1 cells by nitrogen cavitation and Mg/EGTA precipitation methods. The specific activities of marker enzymes for apical membranes were enriched 8- to 18-fold relative to those in the homogenate. D-[3H]Glucose uptake into the vesicles was stimulated in the presence of Na+ gradient (overshoot phenomenon), and the values of apparent Km and Vmax for Na+-dependent component of D-glucose uptake were 0.3 mM and 5.8 nmol/mg protein per min, respectively.

Animals↗
PubMed1984

Enhancement of Newcastle disease virus-induced fusion of mouse L cells by sodium vanadate.

Sodium vanadate enhanced Newcastle disease virus (NDV)-induced cell fusion in L cells, and there was a direct correlation between the degree of cell fusion and the dose of vanadate added. When anti-F protein of NDV monospecific antiserum was added to the culture fluid of L cells infected with NDV, the enhancement of cell fusion was suppressed. In contrast, neither anti-HN nor anti-M protein monospecific antiserum inhibited the enhancement. Incubation at low temperature (4 C) and addition of sodium azide to the culture fluid suppressed the enhancement. The suppression by azide was seen only when the drug was added within 5 min after the beginning of incubation of NDV-infected L cells with vanadate. On the other hand, incubation at low temperature inhibited the enhancement at any time during incubation with vanadate. Cytochalasin D also inhibited the enhancement if it was added at any time during incubation with vanadate.

Animals↗
PubMed1984

Characterization of the autoimmune antigenic determinant for ribonucleoprotein (RNP) antibody.

Small nuclear ribonucleoprotein complexes are antigens in various autoimmune diseases. The serological pattern of high titers of circulating antibody to nuclear ribonucleoprotein (RNP) antigen is a diagnostic marker for mixed connective tissue disease (MCTD); whereas antibody to Sm is prevalent in systemic lupus erythematosus (SLE). Both calf thymus and rabbit thymus are commonly used, excellent sources for preparation of the corresponding antigens RNP and Sm in clinical and research laboratories (A. M. Boak et al., accompanying paper). Thus, biochemical and structural characterization of the minimal antigenic determinant in these preparations is important for its use in the laboratory, as well as significant for understanding MCTD, SLE, and other examples of autoimmunity. Purification and biochemical analyses of immunologically active RNP from many different preparations of calf thymus extract has revealed that the majority of antibody in monospecific MCTD patient sera recognizes an antigen composed of the 165 nucleotide RNA, U1 RNA, and five peptides. Calf thymus U1 RNA was found to be identical in sequence to that of man. A sequence of 55 nucleotides within the 165 nucleotide RNA was the minimal RNA fragment found in RNP particles that were still immunologically active. Two of the RNP peptides react with patient sera monospecific for RNP and thus, are presumably the antigenic peptides complexed with the 55 nucleotide RNA sequence.

Animals↗
PubMed1984

[Regional cerebral blood flow analysis by 133Xe intraarterial injection method. A comparison with cerebral infarction and cerebrovascular dementia].

Nine cases of cerebral infarction (cerebrovascular dementia 4 cases, hemiparesis 4, aphasia 1) were investigated by intraarterial 133Xe injection. Eight of the cases were male and one was female. Ages ranged from 38 to 72, with a mean age of 57.6 years. Two criteria were necessary for a diagnosis of cerebrovascular dementia: the presence of cerebrovascular disease and a score of less than 20 on Hasegawa's dementia scale. Cases of cerebrovascular dementia tended to have a lower mean cerebral blood flow (CBF) value on the white matter by two-compartmental analysis. Two of the five brain areas showed statistically significant differences. These results support the modern theory that cerebrovascular dementia appears as a result of a disturbance of the white matter. Cases of cerebrovascular dementia showed a lower mean CBF value with a coefficient of variance of regional distribution by height over area method. This showed that CBF values in cerebrovascular dementia were generally low and the range of values were narrow. In a comparison of regional CBF and cerebral angiographical findings, cases of cerebrovascular dementia tended to have a lower mean CBF value in proportion to the severity of angiographical findings. In addition, regional CBF showed a tendency to agree closely with angiographical findings.

Adult↗
PubMed1984

Nucleotide sequence analysis of human T-cell leukemia virus type II.

The total nucleotide sequence of an infectious clone of human T-cell leukemia virus type II (HTLV-II) provirus was determined. The provirus has 8,952 nucleotides with a long terminal repeat (LTR) at each end. The LTR consists of 341 +/- 1 bases of U3, 248 +/- 1 bases of R, and 201 bases of U5 regions. There are gag, pol, and env coding frames in this order from the 5' end of the provirus as in other avian or mammalian retroviruses. A coding frame that can code 178 amino acid residues found between gag and pol is supposed to be for a protease that hydrolyses a gag precursor protein to matured gag proteins. The gag and protease genes and the pol and env genes, respectively, partly overlap. In the region termed X between env and 3' LTR, there are three major open reading frames. Oligopeptides deduced from the sequence of one of the open reading frame in HTLV-I were synthesized chemically, and antibodies against these peptides were raised in rabbits. With these antibodies, 41 kdalton and 38 kdalton proteins were detected in cells infected with HTLV-I and HTLV-II, respectively.

Base Sequence↗
PubMed1983

Carrier-mediated transport of amino-cephalosporins by brush border membrane vesicles isolated from rat kidney cortex.

The uptake of cephalosporin antibiotics by brush border membrane vesicles isolated from rat renal cortex has been studied by a rapid filtration technique, demonstrating a carrier-mediated transport system for amino-cephalosporins such as cephalexin and cephradine. The antibiotics were taken up into an osmotically reactive intravesicular space. The uptake of cephalexin was saturable (apparent Km2.2 mM), was inhibited by structural analogues and sulfhydryl reagents, and was stimulated by the countertransport effect, although the Na+ gradient did not affect the uptake. This transport system was essentially different from the transport system for p-aminohippurate in brush border membranes. The uptake properties for cephradine in brush border membrane vesicles appeared to be similar to those for cephalexin. The present results suggest the existence of a carrier-mediated transport system for amino-cephalosporins in brush border membranes. This system may be a part of the mechanism of tubular reabsorption of these antibiotics.

Animals↗
PubMed1983

Detection of cellular receptors for Sendai virus in mouse tissue sections.

We have established a method for detecting virus receptors in the tissue sections and have been able to clarify the distribution of cellular receptors for Sendai virus in various mouse organs, including trachea, esophagus, large intestine and cerebrum. The virus receptors were detected in ciliated cells of the trachea, as to be expected for a pneumotropic virus. The lamina propria and connective tissue of the mouse esophagus and large intestine, immediately under the epithelium, contained an abundance at virus receptors, but very few were detected in the epithelium of these organs. In mouse cerebrum, the cells lining the ventricles had a large number of virus receptors.

Animals↗