Biomedical subjects

Z Wang

Publications and source records attributed to Z Wang.

At least 397 records · Page 22Linked to original sources

PubMed2001

Presence of antibody against the inducible Hsp71 in patients with acute heat-induced illness.

Antibodies against heat shock or stress proteins (Hsps) have been reported in a number of diseases in which they may be involved in the pathogenesis of the disease or may be of use for prognosis. Heat-induced diseases, such as heat cramps, heat exhaustion, or heat stroke, are frequent in hot working or living environments. There are still few investigations on the presence and possible significance of autoantibodies against Hsps in heat-induced illnesses. Using an immunoblotting technique with recombinant human Hsps, we analyzed the presence and titers of antibodies against Hsp60, Hsp71, and Hsp90alpha, and Hsp90beta in a group of 42 young male patients who presented with acute heat-induced illness during training. We also examined the presence of antibody against Hsp71 in a second group of 57 patients with acute heat-induced illness and measured the changes in titers of anti-Hsp71 antibodies in 9 patients hospitalized by emergency physicians. In the first group of young persons exercising in a hot environment, the occurrence of antibodies against Hsp71 and Hsp90alpha was significantly higher among individuals with symptoms of heat-induced illness (P < 0.05) than in the matched group of nonaffected exercising individuals. Moreover titers of antibody against Hsp71 were higher in individuals of the severe and mild heat-induced illness groups, the highest titer being found in the most severe cases. The results from the second group of 57 heat-affected patients exposed to extreme heat were similar. Again, patients with the more severe heat-induced symptoms showed a significantly higher incidence of antibodies to Hsp71 than controls and the titer of anti-Hsp71 was higher in the severely affected group. Finally, in a study of 9 patients, it was observed that the titer of anti-Hsp71 decreased during recovery from severe heat symptoms. These results suggest that measurement of antibodies to Hsps may be useful in assessing how individuals are responding to abnormal stress within their living and working environment and may be used as one biomarker to evaluate their susceptibility to heat-induced diseases.

Adolescent↗

PubMed2001

Elements in erythrocytes of population with different thyroid hormone status.

The contents of elements K, Ca, Fe, Cu, Zn, Se, and Rb in erythrocytes of 78 cases with different thyroid hormone status have been measured by proton-induced X-ray emission and neutron activation analysis. According to the status of thyroid hormones T3, T4, TSH, FT3, and FT4 detected by radioimmunoassay, the experiment subjects were divided into four groups (i.e., hyperthyroid, hypothyroid, critical [one of thyroid hormones was abnormal], and normal). Elements contents and hormones levels of four groups were analyzed by one-way analysis of variance and correlation using an SPSS/PC statistical package. The results showed that the Se contents of four groups were not significantly different (p<0.05). Zn content of hypothyroid group was significantly higher than those of hyperthyroid and critical groups. The Zn content of the normal group was higher than that of the hypothyroid group and lower than that of the hyperthyroid and critical groups. In the hyperthyroid group, there were significant correlations between elements contents and thyroid hormones levels (except TSH), but not between elements contents and levels of thyroid hormones. However, in the hypothyroid group, relatively strong correlations have been found between elements contents and thyroid hormones levels, especially between Zn and the T3/T4 ratio, and between Zn and TSH.

Animals↗

PubMed2001

Concentrations and flux of rare earth elements in a semifield plot as influenced by their agricultural application.

The concentrations of rare earth elements (REs) in atmospheric particles, soil, soil water, surface runoff, and different parts of corn in an experimental plot in the suburb of Beijing, China were measured and the flux of REs was estimated. The concentration of REs in air particles with diameter less than 10 microm is 36 ng/m3 and, by ratio analysis, the origin of REs in the atmosphere was likely local soil. The concentration of soluble REs is 0.69 microg/L in rainwater, 5-7 microg/L in surface runoff, as well as 1-4 microg/L in soil water and the application of RE mixture has no observed influences on their concentrations. The concentration of soluble REs in surface runoff and soil water was dominated by aqueous-solid-phase partitioning. By estimation of the flux, most of the REs applied will remain in the soil phase and continued application of REs will cause an accumulation of REs in agricultural soil.

China↗

PubMed2001

Replication-related activities establish cohesion between sister chromatids.

Replicated sister chromatids are held together from their synthesis in S phase to their separation in anaphase. The process of sister chromatid cohesion is essential for the proper segregation of chromosomes in eukaryotic cells. Recent studies in Saccharomyces cerevisiae have advanced our understanding of how sister chromatid cohesion is established, maintained, and dissolved during the cell cycle. Historical observations have suggested that establishment of cohesion is roughly coincident with replication fork passage. Emerging evidence now indicates that replication fork components, such as PCNA, a novel DNA polymerase, Trf4p/Pol sigma (formerly Trf4p/Pol kappa), and a modified clamp-loader complex, actively participate in the process of the cohesion establishment. Here, we review the molecular events in the chromosome cycle with respect to cohesion. Failure of sister chromatid cohesion results in the aneuploidy characteristic of many birth defects and tumors in humans.

Anaphase↗

PubMed2001

Potato leafhopper (Homoptera: Cicadellidae) injury disrupts basal transport of 14C-labelled photoassimilates in alfalfa.

The potato leafhopper, Empoasca fabae (Harris), is a key pest of alfalfa, Medicago sativa L., in part because of the leafhopper's ability to disrupt upward translocation within phloem tissues. To determine if leafhopper injury also disrupts basal translocation necessary for regrowth and perenniality of alfalfa, we used radiolabeled 14CO2 to measure the basal transport of photoassimilates in injured and healthy plants. In one experiment, less 14C was transported to lower stem tissue of leafhopper-injured plants in comparison to the same tissue of healthy plants in early vegetative and early reproductive stages of alfalfa development. In a second experiment, less 14C was transported to lower stem, crown, and root tissues of injured plants in comparison to the same tissues of healthy, early reproductive plants. The disruption of basal transport caused by potato leafhopper may impact carbon storage and mobilization subsequent to defoliation, winter survival, and nitrogen fixation.

Animals↗

PubMed2001

Movement of Aedes aegypti (Diptera: Culicidae) released in a small isolated village on Hainan Island, China.

A mark-release-recapture experiment was conducted in a small isolated village on Hainan Island, China, to examine the dispersal and movement of adult Aedes aegypti (L.). Two cohorts of mosquitoes marked with uniquely colored fluorescent dye were released at two different sites and recaptured for 6 d at every house in the village using human bait collections. The distribution pattern of houses around release site affected dispersal. The recapture rate of females released at the center of the village was higher (3.49%) than females released at the edge of the village (2.47%). The average day of recapture differed significantly between sexes, but not cohorts. The average day of recapture of females and males released at the center was 2.5 and 1.54 d, respectively. The total number of mosquitoes recaptured was the greatest at premises near the release site, and decreased at a constant rate of 0.43-0.48 with increasing distance from the release site. The proportion of nulliparous females decreased during the first 4 d and proportion of females with developing or mature ovaries increased during the latter half of the experiment. The daily survival rate for females and males released at the center of the village was estimated by log-regression to be 0.763 and 0.52, respectively.

Aedes↗

PubMed2001

Intravenous pharmacokinetics of penicillin G and antipyrine in ostriches (Struthio camelus) and emus (Dromaius novaehollandiae).

Penicillin G and antipyrine, which served as model drugs to assess the relative capacities of renal and hepatic elimination pathways, respectively, were each administered intravenously to six ostriches (Struthio camelus) and to six emus (Dromaius novaehollandiae). Drug concentrations in blood samples collected over a period of 12 hr after administration were assayed, and elimination half-life, mean residence time, clearance, and steady-state volume of distribution were calculated. Mean values for elimination half-life and mean residence time of penicillin G were significantly higher in emus than in ostriches; no significant differences in antipyrine pharmacokinetics between species were demonstrated.

Animals↗

PubMed2001

Determination of menadione sodium bisulfite in pharmaceutical preparations by flow-injection on-line photochemical spectrofluorometry.

A flow-injection on-line photochemical spectrofluorometry (FI-PF) was developed for the determination of menadione sodium bisulfite (MSB) using acetone and sodium sulfite as sensitizing reagents. An injected sample band carried by a water stream was on-line merged with a mixed NaOH, Na2SO3 and acetone solution in a "T" connector. It was then driven to pass a knotted PTFE photochemical reactor (0.5 mm i.d. x 200 cm, KR) that was freely coiled around a 6-W low-pressure mercury lamp. While passing the KR, MSB was derived into an intensively fluorescent compound that was on-line delivered into a flow-through cell and detected therein at an emission wavelength of 459 nm and an excitation wavelength of 336 nm. Under optimized conditions a detection limit of 0.38 microg l(-1) was achieved at a sampling rate of 90 h(-1). Eleven determinations of 0.5 mg l(-1) and 0.05 mg l(-1) MSB standard solution gave RSDs of 0.75% and 1.3%, respectively. The calibration curve was linear in the MSB concentration range 0.005-1.5 mg l(-1). The proposed method was successfully applied to assay the MSB content in MSB injection.

Flow Injection Analysis↗

PubMed2001

Reduced vasorelaxant effect of carbon monoxide in diabetes and the underlying mechanisms.

Carbon monoxide (CO) is an endogenous gaseous factor that relaxes vascular tissues by acting on both the cGMP pathway and calcium-activated K+ (K(Ca)) channels. Whether the vascular effect of CO is altered in diabetes had been unknown. It was found that the CO-induced relaxation of tail artery tissues from streptozotocin-induced diabetic rats was significantly decreased as compared with that of nondiabetic control rats. The blockade of the cGMP pathway with ODQ (1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one) completely abolished the CO-induced relaxation of diabetic tissues but only partially inhibited the CO effect in normal tissues. Single-channel conductance of K(Ca) channels in diabetic smooth muscle cells (SMCs) was not different from that of normal SMCs. However, the sensitivity of K(Ca) channels to CO in diabetic SMCs was significantly reduced. CO (10 micromol/l) induced an 81 +/- 24% increase in the mean open probability of single K(Ca) channels in normal SMCs but had no effect in diabetic SMCs. Longterm culture of normal vascular SMCs with 25 mmol/l glucose or 25 mmol/l 3-OMG (3-O-methylglucose) but not 25 mmol/l mannitol significantly reduced the sensitivity of K(Ca) channels to CO. On the other hand, the sensitivity of K(Ca) channels to CO was regained in diabetic SMCs that were cultured with 5 mmol/l glucose for a prolonged period. The decreased vasorelaxant effect of CO in diabetes represents a novel mechanism for the vascular complications of diabetes, which could be closely related to the glycation of K(Ca) channels in diabetic vascular SMCs.

3-O-Methylglucose↗

PubMed2001

Effects of forage neutral detergent fiber and yeast culture on performance of cows during early lactation.

Sixty Holstein cows were assigned to two treatments at 21 d before calving and were group-fed a prepartum diet with or without yeast culture. After parturition, cows were individually fed one of five treatments for 140 d: 1) 21% forage neutral detergent fiber (NDF) without yeast culture, 2) 21% forage NDF with yeast culture, 3) 17% forage NDF without yeast culture, 4) 17% forage NDF with yeast culture, and 5) 25% forage NDF with yeast culture for 30 d and then switched to diet 4 for 110 d. Cows fed yeast culture prepartum were also fed yeast culture postpartum (60 g/d). A quadratic increase to 25, 21, and 17% forage NDF occurred during the first 30 d in milk (DIM) for dry matter intake, milk yield, and milk protein yield. No differences were observed for yeast culture or interaction of yeast culture and forage NDF for the first 30 DIM. Feeding 17 versus 21% forage NDF increased milk protein percentage and tended to increase dry matter intake as a percentage of body weight from 31 to 140 DIM. During this period, yeast culture tended to increase milk fat percentage and appeared to have positive effects on dry matter intake, milk yield, and milk fat yield when supplemented to diets with 21% forage NDF but not with 17% forage NDF. Feeding 17% forage NDF may be too low for the first 30 DIM but may improve animal performance after 30 DIM compared to 21% forage NDF.

Animals↗

PubMed2001

Inhibition of 5alpha-reductase in rat prostate reveals differential regulation of androgen-response gene expression by testosterone and dihydrotestosterone.

The growth and development of some of the male sex accessory organs such as the prostate requires the conversion of testosterone to dihydrotestosterone (DHT) by 5alpha-reductase. To provide insights into the role of testosterone versus DHT in the prostate, we studied the impact of finasteride, a potent and specific inhibitor of 5alpha-reductase, on the expression of prostatic androgen-response genes in testis-intact rats and in 7-day castrated rats. Finasteride inhibition of the conversion of testosterone to DHT was confirmed by measuring serum and intraprostatic androgens. As expected, finasteride treatment caused a reduction in the wet weight of the prostate in the testis-intact rats and inhibited the testosterone-stimulated prostatic regrowth in the 7-day castrated rats. Although finasteride treatment had little or no effect on the expression of the surveyed androgen-response genes in testis-intact rats, its administration enhanced the expression of many androgen-response genes during the testosterone-stimulated regrowth of the regressed prostate in castrated rats. These observations suggest that testosterone is more potent than DHT in stimulating the expression of many androgen-response genes in the regressed prostate. The expression of androgen-response genes is mainly prostate specific and thus is likely to be associated with androgen-dependent prostatic differentiation. Therefore, testosterone is more potent than DHT in inducing differentiation and weaker in stimulating proliferation during prostate regrowth. The fact that testosterone is a strong inducer of prostatic differentiation has potential clinical implications.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

PubMed2001

Peroxisome proliferator-activated receptor alpha-dependent induction of cell surface antigen Ly-6D gene in the mouse liver.

Spontaneous peroxisome proliferation-related pleiotropic responses occurring in the liver of mice lacking peroxisomal fatty acyl-CoA oxidase (AOX-/-) are attributed to sustained activation of peroxisome proliferator-activated receptor alpha (PPARalpha) by its putative natural ligands that require AOX for their metabolism. In this study, using a gene expression screen, we show that Ly-6 (lymphocyte antigen 6 complex, locus D; mouse ThB), which belongs to a distinctive family of low molecular weight phosphatidyl inositol anchored cell surface glycoproteins, is upregulated in mouse liver with peroxisome proliferation. Increases in Ly-6D mRNA levels are observed in AOX-/- mouse liver with spontaneous peroxisome proliferation and also in the liver of wild-type mice treated with synthetic peroxisome proliferators. Peroxisome proliferators failed to increase hepatic Ly-6D mRNA levels in mice lacking PPARalpha (PPARalpha-/-), suggesting a regulatory role for PPARalpha in the induction of Ly-6D. These observations suggest that changes in certain cell surface proteins also form part of the pleiotropic responses associated with peroxisome proliferation.

Acyl-CoA Oxidase↗

PubMed2001

Evidence of a functional role for the cyclin-dependent kinase-inhibitor p21WAF1/CIP1/MDA6 in promoting differentiation and preventing mitochondrial dysfunction and apoptosis induced by sodium butyrate in human myelomonocytic leukemia cells (U937).

The impact of dysregulation of the cyclin-dependent kinase inhibitor p21WAF1/CIP1/MDA6 has been examined in U937 human monocytic leukemia cells in relation to cell cycle arrest and differentiation following treatment with the histone deacetylase inhibitor sodium butyrate (SB). Cells stably transfected with a p21WAF1/CIP1/MDA6 antisense construct, in marked contrast to their wild-type counterparts, failed to up-regulate p21WAF1/CIP1/MDA6, undergo G1 arrest, or express the maturation marker CD11b when exposed to 1 or 3 mM SB. However, antisense-expressing cells were significantly more susceptible to SB-mediated mitochondrial injury and apoptosis, manifested by increased cytosolic translocation of cytochrome c, activation of pro-caspase 3, and degradation of PARP. Dysregulation of p21WAF1/CIP1/MDA6 did not modify the extent of SB-induced histone acetylation, but did result in cleavage of p27KIP1, Bcl-2 and pRb, as well as diminished levels of full-length underphosphorylated pRb. Finally, dysregulation of p21WAF1/CIP1/MDA6 did not modify SB-mediated down-regulation of E2F-1 or c-Myc, but was associated with enhanced down-regulation of cyclins D1 and E. Together, these findings indicate that in U937 leukemia cells, p21WAF1/CIP1/MDA6 plays a critical functional role in SB-mediated G1 arrest and maturation, and suggest that cells displaying dysregulation of this CDKI respond to SB by engaging a default apoptotic program.

Apoptosis↗

PubMed2001

Genotype and severity of long QT syndrome.

OBJECTIVES: To describe the state of the art of our understanding of the long QT syndromes and to provide the genetic correlation of clinical severity of patients with this disorder. DATE SOURCES: In this review, we outline data that were obtained from work in our laboratory, as well as information reported in the literature. STUDY SELECTION: The information in this review spans the last decade; data were obtained from the studies that had the most impact, as well as from recent work at our laboratory. DATA EXTRACTION: The data reported herein were extracted from the world literature on sudden death and the clinical aspects of long QT syndrome. The genes identified to date, mutations in these genes, and the biophysical perturbations in the mutated ion channels, as well as the severity of disease, are detailed. DATA SYNTHESIS: The extracted data are described as a state-of-the-art review. CONCLUSIONS: The long QT syndromes, genetically heterogeneous disorders due to mutations in genes encoding ion channels, are relatively common causes of syncope and sudden death. The affected genes, along with the genetic background of individuals, determine the clinical severity of disease. An understanding of the mechanisms responsible for long QT syndrome is expected to enable development of specific therapies.

Cation Transport Proteins↗

PubMed2001

[Genetic polymorphism of eight STR loci in the Han population in Henan province].

OBJECTIVE: To investigate the allele frequencies of eight short tandem repeats(STR) loci: TH01, FES, D19S400, D7S820, D16S539, D20S161, D3S1545 and D5S818 in Han population in Henan province. METHODS: DNA was extracted with phenol-chloroform from EDTA-blood samples of the unrelated individuals in Henan province and amplified with PCR technique. The PCR product was analyzed with the undenatured PAGE vertical electrophoresis and silver-stain. RESULTS: The authors got the frequencies of the eight loci. The heterozygosities of the eight loci are 0.66, 0.67, 0.80, 0.76, 0.79, 0.79, 0.78 and 0.78; the discrimination powers are 0.83, 0.83, 0.94, 0.91, 0.93, 0.93, 0.92 and 0.92. CONCLUSION: The heterozygosities of the eight loci are high and the frequencies are in good agreement with Hardy-Weinberg equilibrium, so the eight loci can be used in individual identification testing.

Alleles↗

PubMed2001

Transmodulation of epidermal growth factor receptor mediates IL-1 beta-induced MMP-1 expression in cultured human keratinocytes.

Ultraviolet (UV) irradiation causes human skin aging and skin cancer through the activation of matrix metalloproteinases (MMPs) which are responsible for the degradation of collagen and tumor progression in human skin. The molecular mechanisms of UV-induced MMPs are yet to be defined. Our previous studies and others suggest that i) the transient activation of cell surface receptors and subsequent activation of MAP kinase cascade contributes to the transcriptional up-regulation of MMPs; and ii) UV-induced expression of pro-inflammatory cytokines such as IL-1 beta and TNF-alpha may also account for the expression of MMPs. However, signaling pathway through which cytokines induce MMP expression remains to be unraveled. In this study, we investigated the pathway that leads to the IL-1 beta-induced up-regulation of MMP-1 in human keratinocytes. IL-1 beta activated epidermal growth factor (EGF) receptor in cultured human keratinocytes in a time- and dose-dependent manner. IL-1 beta-induced EGF receptor tyrosine phosphorylation started at 5 min and peaked at 10 min and remained elevated up to 40 min post IL-1 beta treatment. EGF receptor kinase inhibitor PD153035 and AG1478 inhibited IL-1 beta-induced EGF receptor tyrosine phosphorylation. To test the effect of EGF receptor transactivation on downstream components, we examined the ERK activation by IL-1 beta. We found that IL-1 beta-induced ERK phosphorylation, PD153035 and MEK inhibitor PD98059 blocked IL-1 beta-induced ERK activity. Furthermore, both inhibitors also dramatically reduced IL-1 beta-induced expression of c-jun and c-fos mRNA which are required for up-regulation of MMPs. EGF receptor kinase inhibitor PD153035 and AG1478 and MEK inhibitor PD98059 also blocked IL-1 beta induction of MMP-1 in cultured human keratinocytes. Collectively, our data indicate that IL-1 beta-induced expression of MMP-1 is mediated by transactivation of EGF receptor and through ERK pathway in human keratinocytes.

Blotting, Western↗

PubMed2001

Drug-induced hemodynamic perturbations alter the disposition of markers of blood volume, extracellular fluid, and total body water.

Recirculatory pharmacokinetic models for indocyanine green (ICG), inulin, and antipyrine facilitate description of intravascular mixing and tissue distribution following intravenous administration. These models characterized physiologic marker disposition in four awake dogs under control conditions and during phenylephrine, isoproterenol, and nitroprusside infusions. Systemic vascular resistance was more than doubled by phenylephrine and was decreased more than 50% by both isoproterenol and nitroprusside. Dye (ICG) dilution cardiac output (CO) was decreased nearly one-third by phenylephrine, was more than doubled by isoproterenol, and was largely unaffected by nitroprusside. Although phenylephrine reduced CO, the fraction of CO represented by nondistributive blood flow nearly doubled at the expense of blood flow to rapidly equilibrating tissues. The area under the blood antipyrine concentration versus time relationship for 3 min after administration (AUC(0-3 min)) during the phenylephrine infusion was nearly 75% larger than control due to both increased first-pass AUC and an increased fraction of CO represented by nondistributive blood flow. The large increase in CO produced by isoproterenol increased blood flow to rapidly equilibrating tissues and relatively decreased blood flow to slowly equilibrating tissues, because some appeared to equilibrate rapidly. Antipyrine AUC(0-3 min) during the isoproterenol infusion decreased more than 30%, due to decreased first-pass AUC. Nitroprusside changed antipyrine intercompartmental clearances in proportion to CO and, hence, had little effect on antipyrine AUC(0-3 min). These data provide further evidence that changes in antipyrine (a lipophilic drug surrogate) blood flow-dependent distribution after rapid i.v. administration are not proportional to changes in CO but depend on both CO and its distribution.

Adrenergic alpha-Agonists↗

PubMed2001

Active surveillance for acute flaccid paralysis in poliomyelitis high-risk areas in southern China.

OBJECTIVE: On 29 October 2000 poliomyelitis was officially declared to have been eradicated from the Western Pacific Region. This article describes the results of surveillance for cases of acute flaccid paralysis (AFP) in China during the final phase of the eradication effort. METHODS: We conducted hospital-based active surveillance in high-risk areas for poliomyelitis in 5 provinces of southern-China (Sichuan, Yunnan, Guizhou, Guangxi and Jiangxi) between 1995 and 1997 to determine the adequacy of reporting and laboratory diagnosis of cases of AFP. FINDINGS: A total of 1069 AFP cases occurring since 1993 were identified in 311 hospital visits. Less than 50% of AFP cases occurring in 1993 and 1994 had been reported by AFP surveillance, and laboratory diagnosis had been carried out on only a small proportion of these. However, improved cooperation between hospital sectors increased the rate of case reporting and laboratory diagnosis to 85% and 78%, respectively, in 1997. Despite this overall improvement, these two indicators were approximately 10-20% lower in Yunnan Province. Epidemiological analysis revealed that cases of clinical poliomyelitis accounted for as much as one-third of all AFP in 1993 and that some of these cases were clustered. Clusters were rarely observed after 1994. Active surveillance in the China-Myanmar border areas of Yunnan over 1995-96 detected 9 cross-border cases of clinical poliomyelitis, including 2 of wild poliomyelitis. Import of poliomyelitis was thus considered to have occurred frequently until 1996 in this border area of Yunnan. These data were important for the outbreak response immunization carried out in 1996 in the border prefectures of Yunnan. CONCLUSION: Our investigation confirmed a high level of AFP surveillance in poliomyelitis high-risk areas of the five provinces and provided valuable information on the interruption of wild poliovirus circulation in southern China that will be of use to countries in other regions that have yet to eradicate poliomyelitis.

Adolescent↗