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Biomedical subjects

J Shen

Publications and source records attributed to J Shen.

At least 505 records · Page 28Linked to original sources
PubMed1983

Biochemical characterization of glucocorticoid receptors of rat testis.

Rat testis cytosolic glucocorticoid receptors were characterized by DEAE-cellulose chromatography, Sephadex G-100 columns and sucrose-density gradients. The unactivated [3H]dexamethasone-receptor complex showed two distinct peaks of macromolecular bound radioactivity on DEAE-cellulose chromatography. Peak I eluted just after the column wash, while peak II eluted at 0.28 M KCl. Activation of the complex at 25 degrees C for 45 min resulted in a significant increase in peak I with a concomitant decrease in peak II and the appearance of a third peak at 0.18 M KCl. Both the unactivated and activated [3H]dexamethasone-receptor complex, when analyzed on Sephadex G-100 columns, showed a single macromolecular bound radioactive peak having a Stokes radius of 6.5 nm. Treatment of the [3H]dexamethasone-receptor complex (6.5 nm holo-receptor) with trypsin (0.5 microgram/ml) resulted in the appearance of a smaller (2.0 nm) fragment but no intermediate sized forms of the receptor were observed. The complexes sedimented as 7-8 S (in low salt) and as 4.6 S (in high salt) forms in sucrose gradients in the presence or absence of 10 mM molybdate. Steroid unbound receptors were inactivated at 25 degrees C and 4 degrees C with a T 1/2 of 2 h and 24 h, respectively. Ten mM molybdate slightly protected the unbound testis receptor at 25 degrees C. However, molybdate, dithiothreitol, and molybdate plus dithiothreitol were unable to either enhance or reactivate [3H]dexamethasone binding of unbound receptors at 4 degrees C or 25 degrees C. Activation of testis [3H]dexamethasone-receptor complexes resulted in a 2-3 fold enhancement in subsequent binding to testis nuclei in vitro. In addition, we observed that activated [3H]dexamethasone-receptor complexes were precipitated with 30-35% ammonium sulfate, while unactivated complexes were precipitated with 30-40% ammonium sulfate.

Animals↗
PubMed1983

Association between the mammalian 110,000-dalton heat-shock protein and nucleoli.

A rabbit antiserum has been prepared using as antigen the 110,000-dalton mammalian heat-shock protein. This protein was purified for injection by two-dimensional PAGE of heat-shocked Chinese hamster ovary cells. Characterization by immunoautoradiography and immunoprecipitation reveals that the antiserum is specific for the 110,000-dalton protein. Both techniques also reveal that the protein against which the antiserum is directed is induced by heat shock. Indirect immunofluorescence shows that the antigen is primarily localized at or near the nucleolus in cultured cells and numerous murine tissues. Treatment of cultured cells with deoxyribonuclease destroys the organization of staining within the nucleus while ribonuclease appears to completely release the antigen from the nucleus. A binding of the antiserum to cytoplasmic structures is also observed by immunofluorescence. This association with nucleoli may have implications in the regulatory aspects of the heat-shock response.

Animals↗
PubMed1983

An MMPI subscale (Gd): to identify males with gender identity conflicts.

This study reported on the development and cross-validation of a 31-item MMPI Gender Dysphoria subscale (Gd) which accurately discriminates between gender identity patients and matched controls, and identifies males with gender dysphoria syndrome. Both the validity and reliability of the Gd scale has been demonstrated and there is every expectation that the scale has excellent potential for clinical usage. In the construction of the Gd scale, we have addressed the major methodological problems of previous studies which have used psychological tests to assess gender role and identity disturbances: small criterion groups, a lack of an appropriate control group, and prediction of too many false positives.

Adult↗
PubMed1981

The development of the dog nigrostriatal system in organotypic culture.

Portions of the midbrain and the caudate nucleus from newborn dog (1-3 days old) were maintained in explant culture for periods up to 15 weeks. During that time, nerve cells developing in the midbrain explants projected axons into the explants of caudate. Fluorescence microscopic observations indicated that a large number of projective fibers contained catecholamines with many fluorescing terminals visible in caudate explants. Ultrastructural study disclosed synapses in both midbrain and caudate explants. Some axonal profiles in the caudate were compatible with the appearance of catecholaminergic synapses. Neurochemical analysis showed that the nigrostriatal cultures were capable of dopamine uptake and release.

Aging↗
PubMed1977

Select growth of human T lymphocytes in single phase semisolid culture.

Selective growth and clonal proliferation of human T lymphocytes can be achieved by using a single-phase semi-solid methylcellulose system without the requirement of preincubation with lectins. Significant proliferation, however, depends upon the continued presence of Con A or PHA, but not pokeweed mitogen or lipopolysaccharide within the methylcellulose. This procedure eliminates nonspecific agglutination by lectins and allows for direct visualization of colonies and their specific removal and subsequent cloning in liquid phase. Optimal growth and production of colonies greater than 40-cell size require 3 to 9 days. Individual cells can be identified on the basis of E rosette formation and absence of surface immunoglobulin or ability to phagocytize latex particles. Moreover, proliferation is inhibited by antithymocyte but not anti-B cell sera and can be demonstrated with peripheral blood T and MOLT-4 cells, but not with B or Raji cells. Finally, colony formation is not enhanced by the presence of 2-mercaptoethanol. The clonal proliferation of human T lymphocytes has wide application in the study of both antigen recognition and lymphocyte alterations in specific diseases.

Antilymphocyte Serum↗
PubMedDate not supplied

Age-related decrease in cholinergic synaptic transmission in three hippocampal subfields.

The present study was designed to examine the effect of age on cholinergic synaptic transmission in the three principal hippocampal subregions, and to assess whether these effects covary with age-related behavioral deficits. Young (3 week), adult (9 month), and old (24-27 month) rats were first tested on the Morris water task, and most of the old rats were severely impaired on the spatial version. The cholinergic slow epsp was induced by tetanic stimulation of stratum oriens or stratum granulosum, and recorded intracellularly in vitro from CA1 and CA3 pyramidal cells and granule cells in the fascia dentata (FD). The amplitude of the slow epsp was significantly reduced in old rats in all areas (CA1 59%; CA3 55%; and FD 56%). This age-related decrease was also present following the blockade of glutamatergic and GABAergic transmission, ruling out possible artifactual contributions from these systems to the change in the slow epsp. Our data suggest that functional cholinergic transmission is compromised in all areas of the hippocampus during normal aging. Few statistically significant correlations, however, were found between the age-related deficit in spatial learning and the decrease in cholinergic synaptic function.

Aging↗
PubMedDate not supplied

Surveillance for low-level malaria.

Due to good detection and control, malaria has reached very low levels in China with the result that existing methods of surveillance, taking blood slides from all fever cases and those with a common cold, are finding very few malaria cases among the millions of persons examined. Passive case detection agents in areas of moderate and low endemicity in Hubei Province, China, were instructed to indicate on the form associated with each slide whether the patient was considered to be a clinical case of malaria (group 1), was thought to have malaria but did not have all the features (group 2), had fever alone and was not thought to be a case of malaria (group 3), or merely had a common cold (group 4). In the low endemic area (slide positivity rate 0.23%), only 5 cases in group 3 and 4 in group 2 were detected per 10,000 examinations. It is recommended that these categories be discontinued in malarious areas of low endemicity, to encourage greater efficiency in detecting cases in groups 1 and 2. In the moderately endemic area, with a slide positivity rate of 4.19%, all categories, including group 4, were considered valuable for detecting malaria cases.

Adolescent↗