Search PubMed⌕ Search

Biomedical subjects

W Huang

Publications and source records attributed to W Huang.

At least 433 records · Page 24Linked to original sources
PubMed1997

Anabolic androgenic steroids increase beta-endorphin levels in the ventral tegmental area in the male rat brain.

The levels of beta-endorphin and Met-enkephalin-Arg-Phe (MEAP) immunoreactivity in various brain regions (including amygdala, cortex, hippocampus, hypothalmus, nucleus accumbens, pituitary and ventral tegmental area) were studied in male rats subjected to daily intramuscular injections during 14 days of high doses (5 and 15 mg/kg) of the anabolic androgenic steroid (AAS), nandrolone decanoate. At the nandrolone dose of 15 mg/kg a significant (about 20-fold) increase in beta-endorphin levels in the ventral tegmental area (VTA) was observed. The steroid did not significantly affect the concentration of the peptide at any dose in other brain areas examined. The levels of MEAP remained unaltered in all studied regions. A slight increase in serum concentrations of both peptides was also found but this elevation was not statistically significant. The observed increase in beta-endorphin in VTA was suggested to be involved in a mechanism by which the steroid may influence the reward system in the brain. An opioid mediated stimulation of the reward system following injection of AAS supports a previous hypothesis that AAS may induce psychological dependence.

Anabolic Agents↗
PubMed1997

Transport of insulin across the blood-brain barrier: saturability at euglycemic doses of insulin.

Blood-borne insulin is known to cross the blood-brain barrier (BBB) where it can act as a satiety peptide. We examined in mice the pharmacokinetics and characteristics of such passage by multiple-time regression analysis. The unidirectional influx constant (Ki) of human insulin radioactively labeled with iodine (I-Ins) ranged from 0.87 to 1.7 microliters/g-min. The transport of I-Ins was inhibited almost 50% by 0.1 micrograms/mouse of unlabeled human insulin, a dose that had no effect on serum glucose. Similar results were found with rat insulin. The results with self-inhibition suggest that any hemoencephalic signal transmitted by the blood to brain transport of insulin is independent of the effects of insulin on glucose. The transport of I-Ins was altered by aluminum but not by administration of tyrosine, verapamil, or leptin, indicating independence from amino acid transport, the p-glycoprotein system, a slow calcium channel, or leptin transport. By contrast with insulin, enzyme degradation limited the uptake and accumulation by brain of intravenously injected, radioactively labeled glucagon and glucagon-like peptide. In conclusion, these results are consistent with the view that insulin can affect satiety and related behaviors independently of its peripheral effects by crossing the BBB to act within the brain.

Aluminum↗
PubMed1997

Infant mortality among various nationalities in the middle part of Guizhou, China.

This paper describes infant mortality, leading causes of death, and some associated factors among the Han, the Miao, the Bouyei and other minority nationalities in three counties of the middle part of Guizhou Province, China. The results showed that the overall infant mortality rate (IMR) in these areas was 125.7 per 1000 live births during 1985-1987. There existed a great disparity in IMR among different nationalities. The rate was 103.1 (Han), 148.8 (Miao), 161.2 (Bouyei) and 145.0 (other ethnic groups) per 1000 live births, respectively. The five leading causes of death in infants were respiratory diseases, neonatal tetanus, birth asphyxia, infectious diseases and diarrhoea. These causes of death combined resulted in an IMR of 104.1 per 1000 live births. However, these diseases varied in importance for infants of different nationalities. We considered the relationship between infant death and maternal and child health care. The location of birth, the kinds of birth attendants and utilization of health facilities might be associated with differentials of infant mortality among these nationalities. Maternal education was associated with infant survival, but it might not be the only factor in decreasing or eliminating the differential of IMR among various nationalities. Based upon the findings, it is urgent to improve maternal and child health care and investigate further cultural and sociological factors among various nationalities.

Anthropology, Cultural↗
PubMed1997

The mus206 gene of Drosophila melanogaster is required in the excision repair of alkylation-induced DNA lesions.

The mus206A1 mutation, previously identified in our laboratory on the basis of increased sensitivity to methyl methanesulfonate (MMS), has undergone further analysis. Genetic recombinational mapping data localize mus206 at 2-64.8. Sex-linked recessive lethal mutation tests indicate that mus206A1 exhibits significant alkylation-induced hypermutability, compared to the wild-type Oregon R progenitor strain, suggesting a defect in DNA repair function. Results of embryo viability tests show that mus206A1 and Oregon R embryos hatch to the first instar larvae at similar rates, indicating that the mus206A1 mutation does not confer embryonic lethality. Unscheduled DNA synthesis (UDS) studies with primary embryonic cell cultures subsequently demonstrated considerably less nucleotide incorporation following treatment with MMS, confirming that mus206A1 is deficient at or before the resynthesis step of alkylation-induced DNA excision repair. Previous genetic investigations have provided indirect support that at least 15 Drosophila genes which display MMS sensitivity are deficient in DNA repair functions. This study brings to 7 the number of mus genes displaying alkylation excision-repair deficiency.

Alkylating Agents↗
PubMed1997

Spinal cord excitatory amino acid receptors and plasma catecholamine autonomic responses in the conscious rabbit.

Intrathecal administration of the specific glutamate subtype receptor agonist NMDA (N-methyl-D-aspartate), or the non-NMDA receptor agonist AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionic acid), at the level of the lower thoracic spinal cord in the conscious rabbit, produces increased levels of plasma norepinephrine and a rise in blood pressure. These responses are specifically inhibited with prior intrathecal administration of the NMDA receptor antagonist AP-5 (2-amino-5-phosphonovaleric acid) or non-NMDA receptor antagonist DNQX (6, 7-dinitroquinoxaline-2, 3-dione), respectively. In contrast, arterial baroreflex activation induced by transient hypotension following intravenous sodium nitroprusside increases levels of plasma norepinephrine which are inhibited with intrathecal AP-5, but not DNQX. The experiments are consistent with glutamate acting as a neurotransmitter in the spinal cord influencing control of sympathetic nerve function via activation of spinal cord NMDA and non-NMDA subtype receptors. The results support previous work suggesting that baroreflex function is predominantly mediated by spinal NMDA receptors and that spinal glutamate receptors are important in baroreflex control of the circulation.

Animals↗
PubMed1997

Empirical investigation of the signal performance of a high-resolution, indirect detection, active matrix flat-panel imager (AMFPI) for fluoroscopic and radiographic operation.

Signal properties of the first large-area, high resolution, active matrix, flat-panel imager are reported. The imager is based on an array of 1536 x 1920 pixels with a pixel-to-pixel pitch of 127 microns. Each pixel consists of a discrete amorphous silicon n-i-p photodiode coupled to an amorphous silicon thin-film transistor. The imager detects incident x rays indirectly by means of an intensifying screen placed over the array. External acquisition electronics send control signals to the array and process analog imaging signals from the pixels. Considerations for operation of the imager in both fluoroscopic and radiographic modes are detailed and empirical signal performance data are presented with an emphasis on exploring similarities and differences between the two modes. Measurements which characterize the performance of the imager were performed as a function of operational parameters in the absence or presence of illumination from a light-emitting diode or x rays. These measurements include characterization of the drift and magnitude of the pixel dark signal, the size of the pixel switching transient, the temporal behavior of pixel sampling and the implied maximum frame rate, the dependence of relative pixel efficiency and pixel response on photodiode reverse bias voltage and operational mode, the degree of linearity of pixel response, and the trapping and release of charge from metastable states in the photodiodes. In addition, X-ray sensitivity as a function of energy for a variety of phosphor screens for both fluoroscopic and radiographic operation is reported. Example images of a line-pair pattern and an anthropomorphic phantom in each mode are presented along with a radiographic image of a human hand. General and specific improvements in imager design are described and anticipated developments are discussed. This represents the first systematic investigation of the operation and properties in both radiographic and fluoroscopic modes of an imager incorporating such an array.

Bone and Bones↗
PubMed1997

Empirical and theoretical investigation of the noise performance of indirect detection, active matrix flat-panel imagers (AMFPIs) for diagnostic radiology.

Noise properties of active matrix, flat-panel imagers under conditions relevant to diagnostic radiology are investigated. These studies focus on imagers based upon arrays with pixels incorporating a discrete photodiode coupled to a thin-film transistor, both fabricated from hydrogenated amorphous silicon. These optically sensitive arrays are operated with an overlying x-ray converter to allow indirect detection of incident x rays. External electronics, including gate driver circuits and preamplification circuits, are also required to operate the arrays. A theoretical model describing the signal and noise transfer properties of the imagers under conditions relevant to diagnostic radiography, fluoroscopy, and mammography is developed. This frequency-dependent model is based upon a cascaded systems analysis wherein the imager is conceptually divided into a series of stages having intrinsic gain and spreading properties. Predictions from the model are compared with x-ray sensitivity and noise measurements obtained from individual pixels from an imager with a pixel format of 1536 x 1920 pixels at a pixel pitch of 127 microns. The model is shown to be in excellent agreement with measurements obtained with diagnostic x rays using various phosphor screens. The model is used to explore the potential performance of existing and hypothetical imagers for application in radiography, fluoroscopy, and mammography as a function of exposure, additive noise, and fill factor. These theoretical predictions suggest that imagers of this general design incorporating a CsI: Tl intensifying screen can be optimized to provide detective quantum efficiency (DQE) superior to existing screen-film and storage phosphor systems for general radiography and mammography. For fluoroscopy, the model predicts that with further optimization of a-Si:H imagers, DQE performance approaching that of the best x-ray image intensifier systems may be possible. The results of this analysis suggest strategies for future improvements of this imaging technology.

Electronics↗
PubMed1997

SOX9 is a potent activator of the chondrocyte-specific enhancer of the pro alpha1(II) collagen gene.

The identification of mutations in the SRY-related SOX9 gene in patients with campomelic dysplasia, a severe skeletal malformation syndrome, and the abundant expression of Sox9 in mouse chondroprogenitor cells and fully differentiated chondrocytes during embryonic development have suggested the hypothesis that SOX9 might play a role in chondrogenesis. Our previous experiments with the gene (Col2a1) for collagen II, an early and abundant marker of chondrocyte differentiation, identified a minimal DNA element in intron 1 which directs chondrocyte-specific expression in transgenic mice. This element is also a strong chondrocyte-specific enhancer in transient transfection experiments. We show here that Col2a1 expression is closely correlated with high levels of SOX9 RNA and protein in chondrocytes. Our experiments indicate that the minimal Col2a1 enhancer is a direct target for Sox9. Indeed, SOX9 binds to a sequence of the minimal Col2a1 enhancer that is essential for activity in chondrocytes, and SOX9 acts as a potent activator of this enhancer in cotransfection experiments in nonchondrocytic cells. Mutations in the enhancer that prevent binding of SOX9 abolish enhancer activity in chondrocytes and suppress enhancer activation by SOX9 in nonchondrocytic cells. Other SOX family members are ineffective. Expression of a truncated SOX9 protein lacking the transactivation domain but retaining DNA-binding activity interferes with enhancer activation by full-length SOX9 in fibroblasts and inhibits enhancer activity in chondrocytes. Our results strongly suggest a model whereby SOX9 is involved in the control of the cell-specific activation of COL2A1 in chondrocytes, an essential component of the differentiation program of these cells. We speculate that in campomelic dysplasia a decrease in SOX9 activity would inhibit production of collagen II, and eventually other cartilage matrix proteins, leading to major skeletal anomalies.

3T3 Cells↗
PubMed1997

P-selectin-deficient mice are protected from PAF-induced shock, intestinal injury, and lethality.

In a previous study, we showed that anti-CD11b or anti-CD18 antibody markedly attenuated platelet-activating factor (PAF)-induced shock and intestinal necrosis in rats, whereas anti-P-selectin anti-body was ineffective. Here we used genetically altered mice to study the mechanism of PAF in mice. We found that P-selectin-deficient mice are completely protected from the adverse effects of PAF with no mortality or intestinal injury and only mild hemoconcentration and transient hypotension. In contrast, CD18- or intercellular adhesion molecule 1 (ICAM-1)-deficient mice were not protected from PAF-induced tissue injury and death. However, when ICAM-1-, but not CD18-, deficient mice were pretreated with fucoidin, the adverse effects of PAF were markedly reduced; survival was 100%, although hypotension still developed. Neutrophil-depleted mice were protected from PAF-induced intestinal injury but still developed hypotension and hemoconcentration. PAF increases peripheral blood neutrophil counts, probably by inducing granulopoiesis, since neutrophil-depleted mice still showed granulocytosis 60 min after PAF. Thus P-selectin plays an important role in PAF-induced injury in mice, and the selectins and the integrin-ICAM-1 system work in concert to mediate the inflammatory response to PAF in vivo.

Animals↗
PubMed1997

Social skills training for adults with mental retardation in job-related settings.

The authors discuss the rationale for social skills training for workers with mental retardation, definitions and behavioral standards of these skills, and differences in the interaction patterns between workers with and without mental retardation. Various intervention strategies were reviewed critically, and their strengths and limitations were examined. Based on these analyses, the following recommendations are made. First, trainees' environments of ultimate functioning should be considered and contextual variables assessed and used. Second, social validation should be conducted to identify the social behavior that needs to be trained. Third, some procedures that have been found effective in other areas might be used for social skills training for persons with mental retardation in job-related settings. Fourth, active programming should be included in the intervention package for trainees to generalize and maintain the acquired social skills.

Adolescent↗
PubMed1997

Clinical observation of Chinese drugs in prevention of neonatal hyperbilirubinemia.

Observation of the preventive and curative effects of Herba Artemisiae Scopariae [symbol: see text], Fructus Gardeniae [symbol: see text], Radix Scutellariae [symbol: see text] and Radix et Rhizoma Rhei Preparata [symbol: see text] in 30 cases of neonatal hyperbilirubinemia showed that both the peak value of serum total bilirubin and the incidence of hyperbilirubinemia were obviously lower than that in the control group.

ABO Blood-Group System↗
PubMed1997

[Identification of the properties of haptoglobin-like substance in burn serum].

In our previous study, a haptoglobin-like substance possessing immunosuppressive activity was found in the sera of burned patients. However, its properties have not yet been clarified. In the present study, we mainly investigated the properties of the haptoglobin-like substance. The results showed that the abnormal protein bands identified by SDS-PAGE were the different subunits of haptoglobin, i.e., beta, alpha 2 and alpha 1 chains. The haptoglobin in burned sera was identical to that in normal sera in molecular weight, isoelectric point, hemoglobin-binding capacity and immunochemical properties as analyzed by SDS-PAGE, isoelectric focusing, immunochemical and biochemical methods. According to our results, it is suggested that the haptoglobin-like substance reported in the past is probably the haptoglobin, and that there may be no alteration in the properties of haptoglobin following burns.

Animals↗
PubMed1997

[Preliminary study of anatomic relation among nasopalatine duct, central incisor root and floor of nasal cavity with X-ray measurement].

The authors studied anatomic constructure of anaterior maxilla. They observed the position relationships among nasopalatine duct, central incisor root and floor of nasal cavity through X-ray measurement. The results showed: (1) Average distance between the anterior wall of nasopalatine duct and cortical plate of anterior maxilla was 7.80 +/- 1.43 mm. (2) Average distance between the anterior wall of nasopalatine duct and central incisor root was 4.15 +/- 1.48 mm. (3) Average distance between the tip of central incisor root and floor of nasal cavity was 12.62 +/- 2.47 mm. (4) Average length of the nasopalatine duct was 15.04 +/- 2.20 mm. The results are beneficial of dental implantation and orthognathic surgery.

Adult↗
PubMed1997

[Effect of white noise on activity and gene expression of nitric oxide synthase in cochlear nuclei of guinea pigs].

NADPH-diaphorase (NADPH-d) histochemistry method and semiquantitative polymerase chain reaction (PCR) technology were adopted to study nitric oxide synthase (NOS) neurons and to investigate the content change of NOS mRNA and the relationship between it and auditory threshold and to explore the possible role of NOS neurons in cochlear nuclei of guinea pigs after exposed to white noise. The results showed that the quantity and staining intensity of positive NOS neurons in cochlear nuclei increased obviously after exposed to noise. It reached the peak 2 week later and remained 5 week than normal. The regulation of NOS mRNA was consistent with that of morphological observation. NOS mRNA content in 2 w group was the highest and was 4.02 times higher than normal. After exposed to noise, ABR threshold shift was in positive correlation with NOS mRNA content in cochlear nuclei (r = 0.9655, P < 0.01). It is suggested that positive NOS neurons in cochlear nuclei might be involved in controlling injury and repair of cochlear nerves. The high expression of NOS gene might be an important factor in pathogenic mechanism of noise deafness.

Animals↗
PubMed1997

[The expression of P16, Rb and cyclin D1 and biological behavior of laryngeal cancer].

To determine the effect of gene of carcinorma on the proliferation and regulation in primary laryngeal cancer, P16, Rb, Cyclin D1 were examined with immunohistochemical SABC method in 36 cases of primary laryngeal cancer. The results showed: P16 was positive in 11 of 36 in carcinoma specimens (30.6%), 22 of 36 in the specimens surrounding the carcinoma (61.1%) were positive. The difference was significant (P < 0.05). The positive rates of Rb and Cyclin D1 were 61.1% and 47.2% respectively. Comparing the positive rate of P16 to Rb was more significantly (P < 0.05). In most circumstances, when Rb was positive, P16 was negative and vice versa. The positive rate of Rb correlated with the one of Cyclin D1 positively by rank correlation. The expression of P16 and Rb was significantly different between well and poor tissues differenciation. The expression had no significant difference in the same antibody in various clinical stage and position or in the same stage and position but different antibody. The results suggest that the feedback regulation chain consisted of P16 plays an important role in the proliferation and regulation.

Aged↗