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Biomedical subjects

C Wang

Publications and source records attributed to C Wang.

At least 1,135 records · Page 63Linked to original sources
PubMed1992

[Observation of the morphological genesis of pleural mesothelioma induced by asbestos in rats].

In order to observe the lesions of pleural mesothelia caused by asbestos, we injected asbestos fiber into the pleural cavity of Wistar rats. The result showed that there Was an obvious process for the morphological genesis of mesothelioma. Simple hyperplasia and stratified pleomorphic hyperplasia of mesothelial cells were found on the 30th and 106th day after the injection of asbestos fiber, respectively. The benign and malignant mesotheliomas were noted on the 300th day. Meanwhile, a two-way differentiation may be observed in the process of mesothelial hyperplasia.

Animals↗
PubMed1992

Direct effects of progesterone and antiprogesterone on human sperm hyperactivated motility and acrosome reaction.

OBJECTIVE: To study the direct effects of progesterone (P) and its antagonist RU486 (mifepristone) on sperm hyperactivation (HA) and acrosome reaction. DESIGN: Prospective evaluation of semen samples incubated in capacitation media with P and/or RU486. SETTING: University-affiliated tertiary care center. PATIENTS: Normal healthy volunteers. INTERVENTIONS: Semen samples were incubated in media with P or RU486 alone or in combination, and aliquots were taken at 10 minutes, 1, 5, and 24 hours for HA analyses by computer-aided sperm analysis system, and at 0, 5, and 24 hours for assessment of acrosome reaction by fluorescein-labeled Pisum sativum (pea) agglutinin. MAIN OUTCOME MEASURES: HA and acrosome reaction. RESULTS: Sperm HA was significantly increased at 10 minutes by P both at 10(-7) M (9.27 +/- 1.59%; mean +/- SEM) and 10(-6) M (9.39 +/- 1.94%) when compared with untreated spermatozoa (5.62 +/- 1.59%). The stimulatory effect of P on sperm HA was transient because this was not observed after 1, 5, and 24 hours of incubation. The antiprogesterone RU486 (10(-6) M) alone had no effect and did not abolish the stimulatory effect of P on HA. The %HA was further enhanced by the addition of RU486 at 10(-6) M to P at 10(-7) M (12.43 +/- 3.31%) or P at 10(-6) M (13.52 +/- 4.10%); however, this effect was not significantly different from P alone. Coincubation of P or RU486 with spermatozoa during capacitation did not stimulate the acrosome reaction in the concentrations tested. CONCLUSION: Progesterone directly stimulates human sperm HA transiently. Progesterone has no significant effect on acrosome reaction in capacitating spermatozoa. The effects of P are rapid and not counteracted by RU486, suggesting that the mechanism of action of P may not be mediated by specific P nuclear receptors.

Acrosome↗
PubMed1992

[Studies of cockroachcidal toxin].

A cockroachcidal bacterial isolate CW-W-90-3 was selected by egg yolk agar plate. The isolate produced phospholipase C (PLC) which was pathogenic to the nymph of cockroach. The conditions for production of high level PLC indicated that using LB medium supplement Tween-80 or minimal medium could effectively increase the activity of PLC. The optical phase for production of PLC was in the period of 12-18 hours and below pH8.0. The activity of PLC was reduced along with the culture time until 48 hours. The PLC was resistant to heat. The partially purified PLC from the culture supernatant was assayed by using cockroach nymphes and produced 71.74% mortality.

Animals↗
PubMed1992

[Identification of medicinal gualou (fruit-rind of Trichosanthes) and its mixed fruits in Sichuan].

Our investigation shows that in Sichuan Province there are 7 species of medicinal gualou (fruid-rind of Trichosanthes) and its confused fruits (6 species of Trichosanthes and 1 species of Citrullus), among which 2 species are included in the Chinese Pharmacopoeia. The drug and its confused fruits are similar in shape. This paper emphatically deals with the tissue identification of the above mentioned 7 species.

Drug Contamination↗
PubMed1992

Investigation of allotypes of HLA class III (C2, BF and C4) in patients with schizophrenia.

The allotypes of HLA Class III (C2, BF and C4) in 60 patients with schizophrenia were investigated. Significantly higher frequencies of BF*F, BF*SO7 and C4A*4 in patients were found as compared with those of the normal controls. The relative risks (RR) of the three allotypes to schizophrenia were 1.81, 7.79 and 4.18 and the etiologic fraction (EF) were 0.086, 0.060 and 0.042, respectively. There were no significant changes of C2 allotypes.

Complement C2↗
PubMed1991

High-efficiency protein synthesis from T7 RNA polymerase transcripts in 3T3 fibroblasts.

After NIH3T3 cells constitutively expressing T7 RNA polymerase were transfected (+ Ca.phosphate) with a circular DNA containing the firefly luciferase(Luc)-encoding gene (luc) 3' to the encephalomyocarditis (EMC) virus 5'-untranslated sequence and T7 promoter, Luc protein comprising approx. 20% of total cellular protein was obtained. After similar transfection of an analogous construct containing the lacZ gene into the same cell line, at least 50% of the cells produced beta-galactosidase. Fibroblasts lipofected with uncapped RNA transcripts containing EMC sequence expressed the reporter genes as efficiently as capped transcripts. A novel approach was used to generate RNA transcripts containing poly(A) at its very 3' end. RNA from a luc vector with a poly(A) sequence at the very 3' end produced 20-fold more Luc than the RNA from the same vector with an additional 3' nonpoly(A) sequence. These results suggest that this T7 RNA polymerase expression system will be useful for the efficient production of proteins in mammalian cells.

3T3 Cells↗
PubMed1991

Nanos is the localized posterior determinant in Drosophila.

Segmental pattern in the Drosophila embryo is established by two maternal factors localized to the anterior and posterior poles of the egg cell. Here we provide molecular evidence that the localized posterior factor is the RNA of the nanos (nos) gene. nos RNA is localized to the posterior pole of early embryos, and nos protein acts at a distance to direct abdomen formation. Synthetic nos RNA has biological activity identical to that of the posterior pole plasm. Injection of nos RNA rescues the segmentation defect of embryos derived from females mutant for all nine known posterior group genes. Injection of nos RNA into the anterior is able to direct formation of ectopic posterior structures. Our results demonstrate that a localized source of nos RNA is sufficient to specify abdominal segmentation and imply that other posterior group genes are required for localization, stabilization, or distribution of the nos gene product.

Amino Acid Sequence↗
PubMed1991

Developmental regulation in the expression of rat heart glucose transporters.

Antibodies against human erythrocyte glucose transporters (GLUT-1) were used to determine if the transporters of embryonic and adult rat hearts have similar reactivity. On the basis of immunoblotting, these antibodies react more strongly with embryonic transporters than with adult ones. To determine if this phenomenon may be correlated with changes in the expression of transporter types during development, RNA isolated from either the embryonic or the adult rat heart was amplified by polymerase chain reaction (PCR) to identify the transporter species. Both GLUT-1 and GLUT-4 fragments were obtained among the PCR products. They were used for Northern blot analysis. The results indicate that the embryonic heart is rich in GLUT-1 mRNA; whereas the adult heart contains predominantly GLUT-4 mRNA. Thus, it appears that the major type of glucose transporter in rat heart switches from GLUT-1 to GLUT-4 during development.

Aging↗
PubMed1991

Phenylarsine oxide inhibits insulin-dependent glucose transport activity in rat soleus muscles.

Phenylarsine oxide (PAO) is known to block insulin-stimulated glucose transport activity in 3T3 L1 adipocytes at a post-receptor step. Herein, we demonstrate that, at right concentration, PAO also inhibits insulin activation of glucose uptake in rat soleus muscles but does not affect basal level of uptake. In control experiments, insulin stimulation of 2-deoxy-D-glucose uptake is about 400% of that of the control level. After PAO treatment, the stimulation reduces to 150% of the control. Since the intracellular level of ATP remains unchanged after PAO treatment, when measured by phosphorus-31 nmr spectroscopy, this inhibition is not due to depletion of ATP pool size. Moreover, PAO does not affect autophosphorylation of the insulin receptors purified from rat soleus muscles, implying that the PAO blockage of insulin-dependent glucose uptake in soleus muscles also may be post-receptor.

Adenosine Triphosphate↗
PubMed1991

Genetic linkage of autosomal recessive canine narcolepsy with a mu immunoglobulin heavy-chain switch-like segment.

Identification of genes determining narcolepsy susceptibility is important not only for understanding that disorder but also for possible clues to general sleep-control mechanisms. Studies in humans reveal at least one such gene related to the major histocompatibility complex and in dog an as-yet-unmapped single, autosomal recessive gene canarc-1. Gene markers for canarc-1 were therefore sought by DNA restriction fragment length polymorphisms in our colony of narcoleptic dogs. A human mu-switch immunoglobulin probe and the enzyme Hae III identified a gene cosegregating with canarc-1 in backcrossed animals (logarithm of odds scores: m = 24, Z max = 7.2 at theta = 0%). canarc-1 was also shown not to be tightly linked with the dog major histocompatibility complex (m = 40, Z less than -2 at theta less than 4.8%). These results represent the mapping of a non-major histocompatibility complex narcolepsy gene and strongly suggest involvement of the immune system in the pathophysiology of that disease.

Animals↗