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Biomedical subjects

Y Jin

Publications and source records attributed to Y Jin.

At least 523 records · Page 29Linked to original sources
PubMed1989

Effects of gossypol on Na+, K+ transmembrane fluxes in human red cells.

The effects of gossypol-acetic acid (a male contraceptive) on transmembrane fluxes of sodium and potassium in human red cells were studied, in comparison with the effects of ouabain (an inhibitor of Na+-K+-ATPase) and furosemide (an inhibitor of Na+, K+ cotransport). It was found that gossypol may be an inhibitor of outward (Na+, K+) cotransport in human red cells but has no significant effect on (Na+, K+)-ATPase. The results provide new evidence for elucidating the mechanism of hypokalemia caused by gossypol.

Erythrocyte Membrane↗
PubMed1988

Beta-globin mRNAs capped with m7G, m2.7(2)G or m2.2.7(3)G differ in intrinsic translation efficiency.

We examined the intramolecular effect of altered cap structures on translation efficiency of artificial beta-globin mRNAs. For these studies, synthetic dinucleotides of the form X(5')ppp(5')G [X = 7-methyl guanosine (m7G), 2,7-dimethyl guanosine (m2(2,7)G) or 2,2,7-trimethyl guanosine (m3(2,2,7)G)], were transcriptionally incorporated into mRNAs, containing rabbit beta-globin coding sequences, using T7 RNA polymerase and a beta-globin cDNA template. These synthetic mRNAs were assayed in reticulocyte lysate for activity relative to m7G-capped mRNA. m2(2,7)G-Capped mRNA was found to be 1.5-fold more active than m7G-capped mRNA. Messenger RNA capped with m3(2,2,7)G was less active with activity of 0.24 relative to its m7G-capped counterpart (activity = 1.0). These data suggest that m7G-capped mRNAs become more active as translation templates after addition of a single N2 methyl moiety, which is especially pertinent to gene expression in togaviridae. The latter are observed to synthesize m2(2,7)G and m3(2,2,7)G-capped mRNAs in addition to m7G-capped templates during the course of infection in animal cells.

Animals↗
PubMed1988

Human T cell response to the surface antigen of hepatitis B virus (HBsAg). Endosomal and nonendosomal processing pathways are accessible to both endogenous and exogenous antigen.

We have studied the antigen specificity and processing requirements of three vaccine-induced cloned human T cell lines specific for HBsAg, the envelope protein of hepatitis B virus. Each T cell line recognized endogenously expressed antigen as well as exogenous antigen. Two clones required endosomal processing, both for exogenous and endogenous antigen; while the other T cell line depended on nonendosomal processing to generate antigenic peptides from both endogenous and exogenous antigen. Thus, the two processing pathways are accessible to exogenous and endogenous antigen. These results suggest that vaccine-induced T cells can participate actively in the immune response to live virus.

Amino Acid Sequence↗
PubMed1988

Multiple unrelated clonal chromosome abnormalities in an in situ squamous cell carcinoma of the skin.

We have cytogenetically analyzed short-term cultures from an in situ squamous cell carcinoma of the skin (Bowen's disease). The following mosaic tumor karyotype was found: 46,XX, -1, +der(1)(pter----p22::q11----cen----p22:), -9, +der(9)t(1;9)(q11; p24)/46,XX,t(3;6) (q21;p21)/46,XX,t(5;14)(q13;q24),t(7;18)(q32;q11)/46,XX,t(8;11)(p22;q13) /46, XX,t(8;11) (p22;q13),t(15;17) (q13;q24)/46,XX,t(12;15)(q12;p11). None of the rearrangements correspond to previously known cancer-associated abnormalities. Two of the clones are obviously related, and it is reasonable to assume that the t(15;17) developed as an evolutionary change in a cell that already contained t(8;11)(p22;q13). Since five clones without cytogenetic similarities were found in this in situ skin carcinoma, we suggest that the tumor was of polyclonal origin. It is impossible to decide whether all, or indeed any, of the visible abnormalities constitute pathogenetically essential primary changes, or merely represent chromosomal markers of secondary importance in tumorigenesis.

Carcinoma in Situ↗
PubMed1988

Disposition and metabolism of [14C]-amezinium metilsulfate in rats.

Disposition and metabolism of [14C]-amezinium metilsulfate (4-amino-6-methoxy-1-phenylpyridazinium methylsulfate, Risumic) were systematically studied in rats after intravenous (5 mg/kg) or oral (20, 100 mg/kg) administration. After oral administration at 20 mg/kg, blood level reached the maximum (Cmax) of 0.65 microgram eq/ml at 3 h (tmax) and decreased with t1/2 of 8.1 h. Levels in plasma and most tissues elevated to the Cmax at 3 h. The liver level was the highest (61 times as high as plasma level) of all examined tissues. Most tissue levels decreased thereafter essentially in parallel with plasma levels. The findings by whole-body autoradiography essentially agreed with those by radiometry. In lactating rats, milk levels were virtually similar to plasma levels. [14C]-Amezinium metilsulfate radioactivity in fetus and fetal blood was around 0.3 microgram eq/g, being about 1/10 level of maternal plasma level. About 24, 72 and 42% were excreted in urine, feces and bile, respectively. Re-absorption of biliary metabolites accounted for about 31%, being about 13% of orally given [14C]-amezinium metilsulfate. Plasma and aorta contained unchanged amezinium and glucuronide of hydroxyl amezinium MIII. In the brain, the major metabolite was O-demethyl amezinium MV and unchanged drug was not detected. Urinary metabolites were largely MIII glucuronide and the unchanged drug. Biliary metabolite was found composed mostly from MIII glucuronide. In feces, MIII and the unchanged amezinium were found. MIII and its glucuronide were novel metabolites which were identified by thin-layer chromatography and mass spectrometry.

Animals↗
PubMed1987

Iron transfer from ferritin to transferrin. Effect of serum factors.

The transfer of iron from 59Fe-labelled human spleen ferritin to human apotransferrin occurs in the absence of either reducing or chelating agents. The reaction is first order with respect to ferritin and zero order to apotransferrin. The transfer is enhanced by low-Mr substances from human serum such as ascorbate, citrate, bicarbonate and lactate. A mixture of the four molecules at their normal physiological concentrations can increase the iron exchange to the same extent as that observed with an ultrafiltrate of serum. A pathway of intracellular iron mobilization is considered.

Apoproteins↗