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Biomedical subjects

R Teshima

Publications and source records attributed to R Teshima.

118 records · Page 7Linked to original sources
PubMed1984

Ca2+-dependent and phorbol ester activating phosphorylation of a 36K-dalton protein of rat basophilic leukemia cell membranes and immunoprecipitation of the phosphorylated protein with IgE-anti IgE system.

Endogeneous phosphorylation of rat basophilic leukemia cell membranes was investigated. EGTA specifically inhibited the phosphorylation of a protein having an approximate molecular weight of 36,000 dalton (36K-Da protein). Phosphorylation of this protein was enhanced by phorbol-12-myristate-13-acetate in the presence of phosphatidylserine. The phosphorylated 36K-Da protein was specifically immunoprecipitated with IgE and anti IgE antibody. These results suggest that the phosphorylated 36K-Da protein is the beta-chain of the receptor for IgE and that protein kinase C is involved in the phosphorylation mechanism.

Amino Acids↗
PubMed1983

Comparative rates of proteoglycan synthesis and size of proteoglycans in normal and osteoarthritic chondrocytes.

Normal human and osteoarthritic cells were isolated from cartilage with clostridial collagenase. The cells were grown in media as a suspension culture in the presence of 35SO4. Osteoarthritic cartilage of moderate histologic grade (4-8) yielded chondrocytes which incorporated 35SO4 at a rate 3-4 times greater than did normal chondrocytes. The rate of incorporation, however, decreased to normal levels with chondrocytes isolated from mild (grade 0-3) or more advanced (grade 9-13) stages of the disease. These results corroborate those obtained in earlier studies using organ cultures and show that when osteoarthritic cells are isolated from their matrix environment, they continue to synthesize macromolecules at an increased rate. Analysis of the material synthesized by the isolated cells on sizing column demonstrated an inverse relationship between the size of the 35SO4 containing molecules and the severity of the disease.

Animals↗
PubMed1983

Recovery of membrane potentials from diamide-induced depolarization in frog lens fibers.

Measurement of membrane potentials in isolated frog lens fibers was made by means of intracellular microelectrode techniques. The membrane potentials of lens fibers were depolarized to various degrees after exposure to diamide, an -SH inhibitor. When the degree of diamide-induced depolarization was less than 20 mV, the membrane potentials almost fully recovered to the control level within 12 h after immersion in a Ringer's solution containing dithiothreitol (DTT), a -SH protector. A similar tendency was also recognized in some lenses (57%) whose depolarization was 30 mV. When the degree of depolarization was 40 mV, the membrane potentials further depolarized in all cases tested in spite of treatment with DTT. From this study, it is considered that frog lens fibers could not recover their function if the damage was so severe as to produce a membrane depolarization of more 40 mV. Determination of ionic concentrations in lens fibers revealed a highly significant correlation between the degree of diamide-induced depolarization and changes in concentration ratio of Na+/K+.

Animals↗
PubMedDate not supplied

Wild-type p53 gene transfection in human cultured sarcomas: effect of CDDP.

We examined the susceptibility of five human bone and soft tissue sarcoma cell lines to transfection with recombinant p53 adenovirus vector (AxCA-p53). Transfection efficiency was more than 90% at 72 h with AxCA-lacZ at a multiplicity of infection (MOI) of 50 in all the cell lines, except for MG-63 (p53 gene mutated) cells. Western blot analysis showed overexpression of both P21/Waf1 and Bax protein in all the cell lines, implying sufficient and successful p53 gene transfection. AxCA-p53 transfection at MOI of 50 resulted in a significant decline of viable cells at 72 h, due to apoptosis, in NY (mutated) and Saos-2 (deletion), but not in the other three lines. The two apoptosis-induced cell lines showed a gradual increase in Bax expression up to 72 h and non-detectable expression of Bcl-XL from 48 h, suggesting the involvement of an apoptosis-inducing mechanism. Pre-treatment with cis-diamminedichloroplatinum (II) (CDDP) at 0.1 microg/ml significantly suppressed tumor cell viability in NY and HuO-3N1 (mutated), but not in the other three lines including HT-1080 carrying the wild-type p53 gene, implying the existence of different mechanisms for the tumor suppressive effect of p53 gene transfection and CDDP. These results indicate that wild-type p53 gene transfection with CDDP is a promising therapy for some, but not all, non-resectable bone-and soft tissue sarcomas, regardless of intrinsic p53 gene status.

Adenoviruses, Human↗
PubMedDate not supplied

In vivo and in vitro metabolism of 2-methylnaphthalene in the guinea pig.

The metabolism of 2-methylnaphthalene (2-MN) in guinea pigs (in vivo and in vitro) was investigated. Excretion of 2-MN from guinea pigs took place rapidly. In the first 24 hr, nearly 80% of the orally administered 2-[3H]-MN was excreted in the urine in the form of several metabolites, and about 10% of it was recovered in the feces. The major metabolites in the urine were oxidative products of the methyl group of 2-MN (naphthoic acid and its glycine and glucuronic acid conjugates) and accounted for 76% of the total urinary radioactivity in the first 24 hr. S-(7-Methyl-1-naphthyl)cysteine and glucuronic acid and sulfate conjugates of 7-methyl-1-naphthol were also identified as minor metabolites (18% of the total urinary radioactivity). As an in vitro metabolite, the formation of S-(7-methyl-1-naphthyl)glutathione was indicated using the 9,000g supernatant of the homogenate of guinea pig liver. The oral administration of 2-MN (500 mg/kg) to guinea pigs significantly lowered the trichloroacetic acid-soluble sulfhydryl content in the liver.

Animals↗
PubMedDate not supplied

Sensitive determination of zearalenone and alpha-zearalenol in barley and Job's-tears by liquid chromatography with fluorescence detection.

A sensitive and reliable method for liquid chromatographic (LC) determination of zearalenone and alpha-zearalenol in barley and Job's-tears was investigated. The method by which these toxins were determined involves addition of an internal standard (zearalenone 6'-oxime) to barley and Job's-tears samples. Extracts from grain samples were cleaned up by passage through chromatography on piperidinohydroxypropyl Sephadex LH-20 as a lipophilic gel. Individual toxins were resolved by LC on a reversed-phase (ODS) column with fluorescence detection. The detection limit is estimated to be 0.2 ng for zearalenone and alpha-zearalenol standards. Known amounts of zearalenone and alpha-zearalenol (25-1250 ng) were added to a barley sample (5 g). Average recoveries for alpha-zearalenol and zearalenone, respectively, ranged from 96 to 102% (mean CV, 3.6%) and from 96 to 103% (mean CV, 3.3%). This method is applicable to determination of alpha-zearalenol and zearalenone in barley and Job's tears with satisfactory sensitivity and accuracy.

Chromatography, Liquid↗