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Biomedical subjects

C Wang

Publications and source records attributed to C Wang.

At least 1,315 records · Page 73Linked to original sources
PubMed1985

Breastfeeding decline in urban China: an exploratory study.

"Retrospective data collected in two urban neighborhoods of Tianjin, People's Republic of China, reveal a decline in the rate and duration of breastfeeding since the mid-1930's.... The evidence indicates that breastfeeding declined as women became involved in work outside the home, as they adopted a form of postmarital residence that separated them from other relatives, as income increased, and as their rural origins decreased. No evidence was found to indicate a relationship between breastfeeding and parity or sex preferences."

Asia↗
PubMed1985

Gossypol and hypokalaemia.

One major side effect of administration of gossypol as a male fertility regulating agent is the occurrence of hypokalaemic paralysis. We have reviewed the common causes of hypokalaemia in clinical practice and previous studies of gossypol-induced hypokalaemia in animals and man. The available evidences suggest that gossypol induced renal leakage of potassium. The most likely mechanism is a direct toxic effect of gossypol on the renal tubules.

Animals↗
PubMed1985

Clomiphene citrate does not improve spermatozoal fertilizing capacity in idiopathic oligospermia.

Clomiphene citrate (CC) was given to 24 men with idiopathic oligospermia at a daily dose of 25 mg (10 subjects) or 50 mg (14 subjects). Sperm concentration increased slightly after CC treatment in both groups. Sperm motility and morphology remained unchanged. Spermatozoal fertilizing capacity as assessed by the zona-free hamster ova penetration test showed no significant change throughout the treatment period. Two pregnancies occurred in the partners of the subjects treated with 50 mg CC/day, but none occurred in the other group. We conclude that oral administration of CC does not improve fertilizing capacity of sperm as measured by the zona-free hamster ova penetration test in idiopathic oligospermia.

Adult↗
PubMed1985

Interaction between human cervical mucus and sperm surface antibodies.

The immunobead test was used to study the immunoglobulin class of antibodies on sperm before and after penetration through a microcolumn of cervical mucus. Sixteen men with positive sperm antibodies (positive sperm immobilization test) and sperm that penetrated cervical mucus in prior tests were selected for study. However, at the time of study, sperm from seven subjects could not be recovered from the microcolumn. The nine subjects from whom motile sperm were obtained after passage through the column had better sperm mucus penetration tests, lower proportions of sperm binding to anti-IgA immunobeads, and higher proportions of sperm with tail-tip-only binding. Sperm recovered after penetration through the mucus microcolumn displayed a greatly reduced binding to anti-IgA immunobeads in all nine subjects, whereas similar reductions in anti-IgG binding occurred only in four subjects. These results confirm that IgA and sperm-head-directed antibodies are more important than IgG and sperm tail-tip-directed antibodies in impairing sperm penetration of cervical mucus.

Antibodies↗
PubMed1985

The relationship between the human sperm hypoosmotic swelling test, routine semen analysis, and the human sperm zona-free hamster ovum penetration assay.

The functional integrity of sperm membranes of 270 semen samples collected from fertile men and the male partners in couples with infertile marriages was assessed by the hypoosmotic swelling test and the results correlated with routine semen analysis and the human sperm zona-free hamster ovum penetration assay. Semen samples with abnormal semen parameters had lower values of percentage of swollen sperm after hypoosmotic treatment in comparison with those with normal semen parameters. A weak positive correlation was observed between sperm swelling and sperm morphologic features (r = 0.32, P less than 0.05) and between sperm swelling and sperm motility (r = 0.22, P less than 0.05). Insignificant correlation was observed between sperm swelling and in vitro sperm fertilizing capacity, as assessed by the zona-free hamster ovum penetration assay. The results indicate that the sperm swelling test and the zona-free hamster ovum penetration assay are evaluating different functional qualities of sperm that are apparently not associated with each other.

Animals↗
PubMed1985

Insulin-stimulated glucose uptake in rat diaphragm during postnatal development: lack of correlation with the number of insulin receptors and of intracellular glucose transporters.

The insulin responsiveness of the membrane transport system for glucose (2-deoxy-D-glucose) in diaphragm was measured during postnatal development of the rat. At birth, the basal rate of 2-deoxy-D-glucose transport is 3 nmol/min X g and it gradually decreases to 1 nmol/min X g over a period of 40 days. On the other hand, the insulin-stimulated rate of transport is 6 nmol/min X g at birth, it increases to 9 nmol/min X g in 16- to 20-day-old rats, and it decreases again to approximately 4 nmol/min X g in the 40-day-old rats. The stimulation of 2-deoxy-D-glucose transport by insulin is 2-fold at birth and increases to 4- to 5-fold 20 days after birth. The number of insulin receptors in the plasma membrane and the number of intracellular glucose transporters was also measured as a function of age to determine if there might be a correlation between these components of the insulin responsive system and the development of the increased insulin stimulation of 2-deoxy-D-glucose transport. The number of insulin receptors per g of wet weight decreased continuously with increasing age; the diaphragm of 40-day-old rats had about 50% of the receptors present in the diaphragm of the newborn rat. Similarly, the number of intracellular D-glucose transporters per g of wet weight decreased with increasing age; for adult rats, the number of transporters per g of diaphragm was 60% of that of newborn rats. The results indicate that the extent of insulin stimulation of glucose (2-deoxy-D-glucose) transport in the diaphragm during the first 20 days of life is not directly or simply related to the number of insulin receptors or the number of intracellular glucose transporters. The extent of the insulin response depends on some other factor that activates or is part of the machinery for translocation of the transporter.

Animals↗
PubMed1985

Cross-sectional study of semen parameters in a large group of normal Chinese men.

Testicular size, semen characteristics and serum reproductive hormone levels were studied in 1239 normal Chinese men. The mean testicular size of 17 ml in this group of subjects was similar to other reports in Orientals but was smaller than that reported in Caucasians. Semen volume, and the sperm count, motility and morphology were comparable to those described for Caucasian subjects. The cervical mucus penetration test (Kremer's test) and the zona-free hamster egg penetration test were also studied in some of the subjects. Age showed a positive correlation with the serum levels of FSH and LH, which were highly correlated with each other. Sperm concentration and the total sperm count were positively correlated with testicular volume, the length of abstinence, the % of sperm with an oval head, and the zona-free hamster egg penetration test, but were negatively correlated with serum FSH. Sperm motility was negatively correlated with the duration of abstinence but was positively correlated with the % normal sperm. The results constitute a normal data base from Chinese men for comparison with studies in male infertility and fertility regulation.

Adult↗
PubMed1985

Primary hypothyroidism and essential hypernatremia in a patient with histiocytosis X.

A 27 year old woman with histiocytosis X had an unusual initial presentation with features of primary hypothyroidism and a goitre. Diagnosis was made by lung and thyroid biopsies. Endocrine tests showed the presence of hypopituitarism and a discrete suprasellar mass, consistent with hypothalamic histiocytosis X, was demonstrated by computerised tomography. Radiotherapy and chemotherapy arrested the clinical progression of the disease.

Adult↗
PubMed1985

Changes in myocardial oxygen demand and instantaneous ventricular vascular volume during prolonged cross-clamping and reperfusion of the abdominal aorta.

In 47 animals (rats, rabbits) the cardiac side effects of prolonged (3 to 6 hours) abdominal aortic cross-clamping and unclamping (3 to 6 hours) were investigated. The relative instantaneous ventricular vascular volume (IVVV), a factor reflecting myocardial blood supply and the rate pressure product (RPP) representing myocardial oxygen demand were used as parameters. Following cross-clamping the IVVV showed an initial decrease while the myocardial oxygen demand revealed a sudden increase. After unclamping, the myocardial oxygen demand decreased and IVVV improved. Minimal levels of both IVVV and RPP occurred at 6 hours following unclamping. This may be an effect of a myocardial inhibiting substance, released by ischemia and necrosis of the lower extremity.

Animals↗
PubMed1984

Neurons in the ventral tegmentum have separate populations projecting to telencephalon and inferior olive, are histochemically different, and may receive direct visual input.

The connections of the ventral tegmental area (VTA) and medial terminal nucleus (MTN) of the accessory optic system were studied in the albino rat. Using injection of two fluorescent retrograde tracers it was found that individual neurons of the VTA project to frontal cortices or the inferior olive but not both structures. Using combined retrograde fluorescent tracers and glyoxylic acid histochemistry, it was found that although a third of the cells projecting to frontal cortex contained catecholamine, none of the cells projecting to the inferior olive contained catecholamine. Thus, these portions of the ascending and descending VTA systems are independent. In addition, using injections of the anterograde transneuronal tracer [3H]adenosine into one eye, it was found that cells in the VTA, as well as the MTN, contained the tracer. Therefore, there is a basis for direct retino-mesentelencephalic pathways through the VTA.

Animals↗
PubMed1984

Arsenite-induced changes in methylation of the 70,000 dalton heat shock proteins in chicken embryo fibroblasts.

Methylated lysyl and arginyl residues are present in the two major heat shock proteins, hsp70A and hsp70B, of chicken embryo fibroblasts. Here, we demonstrate that this methylation can be modulated by sodium arsenite, a chemical that increases the synthesis of hsp70. In particular, in hsp70A the amount of epsilon-N-trimethyl-lysine significantly decreases and the amount of epsilon-N-dimethyl-lysine and epsilon-N-monomethyl-lysine increases, while in hsp70B, the quantity of NG-monomethyl-arginine is reduced fivefold after arsenite treatment. To determine the specificity of these changes in methylation the pool size of S-adenosyl-L-methionine (AdoMet) and the total cellular level of methylated protein was measured. After arsenite treatment, no significant change in AdoMet pool size and the level of protein methylation was observed with the exception of an apparent increase in NG-monomethyl-arginine in total cellular protein. Thus, the arsenite-induced changes in methylation of hsp70 polypeptides are not a generalized phenomenon and may reflect a modulation in the structure or function of these two polypeptides after their induced synthesis by this chemical.

Amino Acids↗
PubMed1984

Insulin autoimmunity as a cause of hypoglycemia.

"Autoimmune" hypoglycemia is a syndrome consisting of fasting hypoglycemia, hyperinsulinemia, and insulin-binding antibodies in a patient who has never been exposed to exogenous insulin. The stimulus for insulin-antibody formation and the mechanism of the hypoglycemia in this condition remain unknown. Three patients with this rare syndrome had severe hypoglycemia of limited duration. Two had received a drug containing a sulfhydryl group (methimazole and penicillamine) as treatment for an autoimmune disorder (Graves' disease and rheumatoid arthritis, respectively). A third patient who underwent surgery for a suspected insulinoma was found to have pancreatic beta cell hyperplasia. Drugs containing a sulfhydryl group may have a role in the etiology of the syndrome. Additionally, our findings suggest a relationship between circulating insulin antibodies and beta cell hyperplasia.

Autoantibodies↗
PubMed1983

Dopamine- and cholecystokinin-containing neurons of the crossed mesostriatal projection.

The projection of the substantia nigra-ventral tegmental area (SN-VTA) to the ipsilateral and contralateral caudate-putamen was studied with double-labeling fluorescence techniques in the albino rat. By combining glyoxylic acid histofluorescence with retrograde fluorescence tracers, we were able to determine that 93% of the minor (1-2%) contralateral mesostriatal pathway is catecholaminergic. In addition, combined immunofluorescence and retrograde fluorescence tracer studies showed that 50% of the crossed mesostriatal pathway also arises from cholecystokinin-containing neurons. These results provide evidence for crossed catecholamine- and peptide-containing pathways in the mesostriatal system which is part of the 'prefrontal system' that links the prefrontal cortex through the caudate-putamen, with the thalamus and tectum of each hemisphere.

Animals↗