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C Wang

Publications and source records attributed to C Wang.

At least 1,063 records · Page 59Linked to original sources
PubMed1993

PDGF and its receptors in the developing rodent retina and optic nerve.

We have used in situ hybridization to visualize cells in the developing rat retina and optic nerve that express mRNAs encoding the A and B chains of platelet-derived growth factor (PDGF-A and PDGF-B), and the alpha and beta subunits of the PDGF receptor (PDGF-alpha R and PDGF-beta R). We have also visualized PDGF-A protein in these tissues by immunohistochemistry. In the retina, PDGF-A mRNA is present in pigment epithelial cells, ganglion neurons and a subset of amacrine neurons. PDGF-A transcripts accumulate in ganglion neurons during target innervation and in amacrine neurons around the time of eye opening, suggesting that PDGF-A expression in these cells may be regulated by target-derived signals or by electrical activity. In the mouse retina, PDGF-A immunoreactivity is present in the cell bodies, dendrites and proximal axons of ganglion neurons, and throughout the inner nuclear layer. PDGF-alpha R mRNA is expressed in the retina by astrocytes in the optic fibre layer and by a subset of cells in the inner nuclear layer that might be Müller glia or bipolar neurons. Taken together, our data suggest short-range paracrine interactions between PDGF-A and PDGF-alpha R, the ligand and its receptor being expressed in neighbouring layers of cells in the retina. In the optic nerve, PDGF-A immunoreactivity is present in astrocytes but apparently not in the retinal ganglion cell axons. PDGF-alpha R+ cells in the optic nerve first appear near the optic chiasm and subsequently spread to the retinal end of the nerve; these PDGF-alpha R+ cells are probably oligodendrocyte precursors (Pringle et al., 1992). RNA transcripts encoding PDGF-B and PDGF-beta R are expressed by cells of the hyaloid and mature vascular systems in the eye and optic nerve.

Animals↗
PubMed1993

Identification of hyaluronan binding proteins using a biotinylated hyaluronan probe.

A method for detecting hyaluronan (HA)-binding proteins in transblot assays using biotinylated HA (BHA) is described. Some of the binding characteristics of a novel HA receptor termed RHAMM (Receptor for HA-Mediated Motility) are characterized using this assay. The method is also used to detect other HA-binding proteins in tissue homogenates. This method is semiquantitative, rapid, reproducible, sensitive and therefore of potential use in identifying the levels of HA-binding proteins in different cells and tissues.

Animals↗
PubMed1993

The effect of polyols on the stability of duplex DNA.

It has been observed that double stranded DNA in solution is thermally destabilized by the presence of several organic molecules, among which are alcohols and polyols. This finding, and the fact that sugar moieties are components of some nuclear proteins and DNA binding drugs, may suggest a role for oligosaccharides in DNA recognition and/or interaction. In order to investigate this possibility, the effect of several sugars and other polyols on the thermal stability and on the conformation of DNA has been studied by high sensitivity differential scanning calorimetry and circular dichroism. While addition of small size polyols does not influence appreciably the melting enthalpy, it always results in a decrease in the DNA melting temperature. The magnitude of the destabilizing effect depends on the concentration of additives, reaching 13.5 degrees C in 50% (5.4M) glycerol. It also depends on the nature of the additives, e.g., sorbitol is more efficient than inositol, while dextran has no effect on the DNA melting temperature. According to circular dichroism results, DNA undergoes a significant structural change in the presence of small sugars or polyols: a continuous loss in 'B' character is observed as the glycerol concentration is gradually increased. This conformation change appears to be related to the decrease in thermostability.

Animals↗
PubMed1993

[Influence of capsaicin treating sciatic nerve on the pain threshold and the effect of acupuncture analgesia of rats].

The model of local application of 1.5% Capsaicin (Cap) on the right sciatic nerve and control of Vehicle (Veh) on the left were used. The influence of Cap on pain threshold, electroacupuncture (EA) analgesia and Fluoride-resistant acid phosphatase (FRAP) activity in the dorsal horn of spinal cord were observed. The results showed, the pain threshold of Cap treatment side rose significantly compared with the control side, FRAP in dorsal horn of spinal cord vanished, and the analgesic effect of EA at "Huantiao" of the Cap treatment side markedly decreased, compared with not only that EA at the control side but also that EA before Cap treatment. It is indicated that the C fibers of the primary afferent participate in the input of pain and EA analgesic information.

Acid Phosphatase↗
PubMed1993

[Pathologic observation of 298 rat mesotheliomas induced by asbestos].

Two hundred and ninety eight rat mesotheliomas induced by chrysotile or crocidolite were studies. The results demonstrated that tumor masses were scattered extensively. The appearance of tumor was polymorphous. According to the microscopic features, the 298 cases of mesothelioma could be histologically classified into three types, i.e. epithelial type, fibrous type and mixed cell type. The malignant mesothelioma is characteristic of its polymorphism and the clear cancernation of mesothelial cells.

Animals↗
PubMed1993

Regulation of platelet-derived growth factor A messenger RNA translation in differentiating F9 teratocarcinoma cells.

We have monitored production of platelet-derived growth factor (PDGF) in F9 teratocarcinoma cells. We show that undifferentiated F9 cells express PDGF A mRNA and produce biologically active PDGF AA homodimers. When differentiation is induced by treatment with retinoic acid and cyclic AMP, the production of PDGF AA protein is terminated. Contrary to expectation, inhibition of PDGF synthesis is exerted at a posttranscriptional level. Both undifferentiated and differentiated (1 day) F9 cell cultures contain comparable amounts of PDGF A mRNA. However, this mRNA becomes dissociated from polysomes during F9 cell differentiation.

3T3 Cells↗
PubMed1993

Androgen deficiency and aging in men.

Androgen levels decrease with age in men. Androgen deficiency in men older than 65 years leads to asthenia, a decrease in muscle mass, osteoporosis, and a decrease in sexual activity. Androgen deficiency has been reported to cause changes in mood and cognitive function. The combination of these factors results in impaired quality of life in older men. Androgen replacement therapy in hypogonadal men increases bone and muscle mass, enhances muscle and cardiovascular function, and improves sexual function and general well-being; whether elderly men experience benefits of androgen replacement is not known. These benefits have to be weighed against the possible adverse effects of prostate and cardiovascular diseases. Careful long-term studies are needed to assess the risk-to-reward ratios of androgen or other hormone replacement therapy before treatment strategies similar to estrogen therapy for postmenopausal women are implemented.

Aged↗
PubMed1993

[An epidemiological investigation on lung cancer and other tumours among coal workers with pneumoconiosis].

A retrospective cohort study was made on lung cancer and all tumours among coal workers with pneumoconiosis in the Haibowan Mining Bureau. Results indicated that the mortality of lung cancer among workers with pneumoconiosis was distinctly higher than that among the local population (P < 0.005, RR = 56.1, AR = 225.2, SMR = 8.07, P < 0.01). The mortality of all tumours among staffs and workers in the Haibowan Mining Bureau was 599.4 per one hundred thousand, but only 62.5 among the local population (P < 0.005). It is suggested that lung cancer in workers exposed to coal dust for more than 18 years should be regarded as occupational cancer.

Adult↗
PubMed1993

[The permissive action of glucocorticoid on the analgesic effect of kyotorphin and its analogue].

Kyotorphin (KTP) is an endogenous analgesic dipeptide which does not act on opiate receptors but may induce the release of endogenous opioid met-enkephalin. In order to investigate whether or not glucocorticoids have "permissive action" on KTP, hydrocortisone has been used to examine its action on the analgesic activities of KTP and its retro-isomer (riKTP) by employing thermal irradiation-tail flick method after intracerebroventricular injection. KTP and riKTP showed dose-dependent analgesic activity. Dose of KTP in the range of 6-24 mmol/L were effective, while the dose of riKTP at 6 mmol/L was shown to be ineffective. The analgesia of KTP was higher than that of riKTP. Hydrocortisone alone showed no significant analgesic effect. Linkers by connecting hydrocortisone with KTP or riKTP showed significantly higher analgesic effect compared with the corresponding dipeptides, not only in the duration of analgesia but also in potency. Solutions containing hydrocortisone and any one of the dipeptides exhibited the same effect as the linker. Pretreatment with sc naloxone (10 mg/kg) 15 min before icv of KTP or riKTP (24 mmol/L) could not block the analgesia. These findings implicate that: (1) Glucocorticoids have a permissive action on the analgesia of KTP and its retro-isomer. The glucocorticoids may exert its effects by acting on receptors in the membrane, and thus cause fast membrane effect. (2) KTP may also induce release of substances other than met-enkephalin to participate in the analgesia.

Analgesics↗
PubMed1993

[The changes of right ventricular function in the course of COPD induced cor pulmonale].

A study on pulmonary hemodynamics, radionuclide right ventricular ejection fraction and blood gas analysis in 62 cases of COPD induced cor pulmonale at different stages showed the following results: 1. In early stage of cor pulmonale, stroke volume could not increase after exercise, it proved that cardiac reserve has been reduced; 2. With the progression of the disease, cardiac stroke volume reduced but cardiac output increased gradually, it could be considered as the evolutionary characteristic of cardiac function in chronic cor pulmonale; 3. The right ventricular stroke work was normal and could increase with the rise of after-load, reflecting the relatively effective functional compensation; 4. In acute exacerbation of cor pulmonale, the cardiac failure should be attributed to hyperdynamic type with hypervolemia; 5. Correlation analyses suggested that cardiac output decreased along with the increase of right ventricular afterload only in acute exacerbation of late cor pulmonale; PaO2 and PaCO2 have only slight influence on right ventricular function.

Adult↗
PubMed1993

Effects of pentoxifylline on sperm motility and hyperactivated motility in vitro: a preliminary report.

Previous reports (2, 3) have suggested that pentoxifylline increases sperm motility. In this preliminary report based on five asthenozoospermic and five normal motility semen samples, we were unable to demonstrate any statistically significant effect of pentoxifylline on percent motility of human spermatozoa. However, in vitro exposure to capacitation medium with pentoxifylline may lead to an increase in total hyperactivated motility in asthenozoospermic samples, an effect not evident in the normal motility samples in this study.

Humans↗
PubMed1993

The effects of Vero (green monkey kidney) cell coculture on the motility patterns of cryopreserved human spermatozoa.

OBJECTIVE: To determine the effects of Vero (a primate, urogenital epithelium-derived cell line) cell monolayer coculture on cryopreserved human sperm function in vitro. DESIGN: Prospective, controlled investigation in which cryopreserved semen specimens were thawed, processed, and then simultaneously exposed to control media (Dulbecco's modified Eagle's medium with either 10% heat-inactivated fetal bovine serum [FBS] or 10% heat-inactivated pooled human sera [PHS]) or the same media with the addition of confluent Vero cell monolayers. A second series of investigations was also performed to study the effect of Vero cell conditioned media (CM). SETTING: In vitro fertilization/andrology service of tertiary center. PATIENTS: Donors with normal semen parameters. INTERVENTIONS: Coculture of human spermatozoa with Vero cell monolayers or Vero cell CM. MAIN OUTCOME MEASURES: General and hyperactivated (HA) motility patterns, multifactor, repeated measures ANOVA. RESULTS: General sperm motility parameters, including percentage motility, mean velocity, and mean amplitude of lateral head displacement were significantly greater than controls in the Vero cell monolayer-FBS group at 6 hours and in both the Vero cell monolayer-FBS and Vero cell monolayer-PHS groups by 24 hours. Hyperactivated motility was increased after 3 hours in the Vero cell monolayer-FBS coculture group. A significant decrease in the total sperm concentration over the time course of the study in the Vero cell monolayer, but not the control or Vero CM groups, was also noted. Vero CM did not exert significant effects on any sperm motility parameter, in spite of a sample size sufficient to detect relevant increases with a power of 0.80. CONCLUSIONS: Vero cell monolayers have a positive influence on cryopreserved sperm function as assessed by general and HA motility patterns. Epithelial cell to spermatozoon contact seems to be important in this process.

Animals↗
PubMed1993

Human sperm hyperactivation and acrosome reaction and their relationships to human in vitro fertilization.

OBJECTIVE: To determine the relationships between human sperm hyperactivation (HA) and acrosome reaction with fertilization of human oocytes in vitro. DESIGN: Prospective analysis of infertile patients undergoing IVF. SETTING: Tertiary center for infertility and assisted reproductive technology. PATIENTS: Fifty-two couples who underwent IVF or GIFT were studied. The male partners had normal semen parameters on routine analyses. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Sperm HA in seminal fluid and after 1 and 6 hours incubation in capacitation media; sperm acrosome reaction after 0, 6, and 24 hours' incubation in capacitation media; and fertilization rate of human oocytes. RESULTS: The percent spermatozoa with transitional HA after 6 hours of incubation correlated significantly with the fertilization rate of human oocytes. Multivariate discriminant analyses selected six sperm HA and acrosome reaction variables of predictive value in classifying semen samples that achieved fertilization rates above and below 70% threshold. Combination of the selected sperm HA and acrosome reaction variables in seminal fluid and after different times of incubation in capacitation medium classified the samples achieving good or poor fertilization rate with > 80% accuracy. CONCLUSIONS: Assessment of sperm HA and acrosome reaction may be of prognostic value in prediction of human oocyte fertilization rates.

Acrosome↗
PubMed1992

Nonenzymic glycation of albumin by acyl glucuronides in vitro. Comparison of reactions with reducing sugars.

Acyl glucuronides are ubiquitous metabolites formed from acidic xenobiotics and endogenous compounds, such as bilirubin. Previous studies indicated that the covalent binding of acyl glucuronides to proteins occurs via an imine intermediate in a manner analogous to the glycation of proteins via reducing sugars. When glucuronic acid was incubated in solution with albumin, it formed 10 and 4 times more fluorescent, Maillard reaction products with albumin after 25 days than did glucose or fructose, respectively. However, radiolabeled glucuronic acid exhibited less covalent binding to albumin than either glucose or fructose. Circular dichroism measurements indicate that glucuronic acid is about 0.02% open chain form with exposure of the reactive aldehyde, whereas fructose and glucose have 2 and 0.0026% present in solution as the open chain; thus, differences in reactivity of the reducing sugars were not correlated with exposure of the free aldehyde. Methyl glucuronate formed little fluorescent product with albumin, suggesting that the C-6 carboxylate of glucuronic acid may facilitate the reactions after covalent binding that lead to the formation of fluorescent products. When acyl glucuronide metabolites of two previously marketed acidic drugs, zomepirac and suprofen, were incubated with albumin at a concentration of 2.5 mM, more fluorescent product was formed than by 500 mM glucose. Reversible binding of the acyl glucuronides to albumin was 60-90%, but almost zero for the free reducing sugars, which indicates that reversible binding may explain the enhanced reactivity of the acyl glucuronides in forming fluorescent products with albumin. These results indicate that acyl glucuronides are reactive metabolites that may cause significant glycation of proteins with glucuronic acid in vivo.

Animals↗