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Q Y Wang

Publications and source records attributed to Q Y Wang.

At least 19 recordsLinked to original sources
PubMed2001

Cold acclimation can induce microtubular cold stability in a manner distinct from abscisic acid.

The response of cortical microtubules to low temperature was investigated for the Chinese winter wheat (Triticum aestivum L.) cultivar Jing Nong 934. Microtubules in the cortex of the root elongation zone disassembled rapidly in response to a cold shock of -7 degrees C and reassembled upon rewarming to 25 degrees C. The microtubules acquired resistance against this cold shock in response to cold acclimation in chilling, but non-freezing, temperature or after a treatment with abscisic acid (ABA). Cold acclimation and ABA differed with respect to the appearance of microtubules: fine, transverse strands were observed after cold acclimation, whereas ABA produced steeply oblique microtubule bundles. The findings are discussed in terms of an ABA-independent pathway for acquired cold stability of microtubules.

Abscisic Acid↗
PubMed2001

Role of calcium in protein folding and function of Tva, the receptor of subgroup A avian sarcoma and leukosis virus.

Tva is the cellular receptor for subgroup A avian sarcoma and leukosis virus (ASLV-A). The viral receptor function of Tva is determined by a 40-residue cysteine-rich motif called the LDL-A module. In this study, we expressed and purified the wild-type (wt) Tva LDL-A module as well as several mutants and examined their in vitro folding properties. We found that, as for other LDL-A modules, correct folding and structure of the Tva LDL-A module is Ca2+ dependent. When calcium was present during in vitro protein folding, the wt module was eluted as a single peak by reverse-phase high-pressure liquid chromatography. Furthermore, two-dimensional nuclear magnetic resonance (NMR) spectroscopy gave well-dispersed spectra in the presence of calcium. In contrast, the same protein folded in vitro in the absence of calcium was eluted as multiple broad peaks and gave a poorly dispersed NMR spectrum in the presence of calcium. The calcium affinity (Kd) of the Tva LDL-A module, determined by isothermal titration calorimetry, is approximately 40 microM. Characterization of several Tva mutants provided further evidence that calcium is important in protein folding and function of Tva. Mutations of the Ca2+-binding residues (D46A and E47A) completely abrogated the Ca2+-binding ability of Tva, and the proteins were not correctly folded. Interestingly, mutations of two non-calcium-binding residues (W48A and L34A) also exerted adverse effect on Ca2+-dependent folding, albeit to a much less extent. Our results provide new insights regarding the structure and function of Tva in ASLV-A entry.

Alpharetrovirus↗
PubMed2001

Modeling fatigue damage evolution in bone.

A simple analytical model for damage evolution of bone fatigue is presented. A probabilistic method for characterizing the damage accumulation in terms of microcracks for bone fatigue was developed. The crack numerical density distributions were obtained from the Monte Carlo simulations with a Weibull distribution fit in this study. The results predicted from the present model are compared with existing experimental data and discussed. The quantitative relationship between stiffness loss, loading cycles and microdamage parameter developed in this study may be useful for fatigue life and failure stress predictions.

Animals↗
PubMed2000

Transfer of lead via placenta and breast milk in human.

The mean lead levels in the maternal blood, cord blood, breast milk and placental tissue, were 0.63 mumol/L (13.2 micrograms/dL), 0.33 mumol/L (6.90 micrograms/dL), 4.74 micrograms/L and 0.86 mumol/kg (17.85 micrograms/100 g) respectively for 165 parturient women occupationally non-exposed to lead in 2 hospitals in Shanghai. No significant difference was found between maternal age groups for these indicators. However, the lead levels in the cord blood and breast milk increased with the lead level in the maternal blood, with coefficient of correlation of 0.714 (P < 0.0001) and 0.353 (P < 0.01) respectively. The mean concentration of lead in breast milk for 12 occupationally lead exposed women was 52.7 micrograms/L, which was almost 12 times higher than that for the occupationally non-exposed population. These results suggested that transfer of lead via placenta prenatally and breast milk postnatally were possible and might pose a potential health hazard to the fetuses and the neonates.

Adult↗
PubMed1998

The auxin response of actin is altered in the rice mutant Yin-Yang.

The rice mutant Yin-Yang has been selected during a screen for resistance to cytoskeletal drugs and is characterized by alterations in epidermal cell length and a precocious onset of gravitropism. The elongation response of coleoptile segments to auxin does not reveal changes of auxin sensitivity in Yin-Yang. However, in contrast to the wild type, cell elongation in Yin-Yang is highly sensitive to the actin-polymerisation blocker cytochalasin D. This increased sensitivity to cytochalasin D requires optimal concentrations of auxin to become manifest. The auxin response of actin microfilaments in epidermal cells differs between wild type and mutant. In the wild type, the longitudinal microfilament bundles become loosened in response to auxin. In the mutant, these bundles disintegrate partially and are replaced by a network of short filaments surrounding the nucleus. Several aspects of the mutant phenotype can be mimicked in the wild type by treatment with cytochalasin D. The mutant phenotype is discussed in terms of signal-dependent changes of actin dynamics and the putative role of actin during cell elongation.

Actin Cytoskeleton↗
PubMed1996

Genetic diversity of human parvovirus B19: sequence analysis of the VP1/VP2 gene from multiple isolates.

To evaluate the genetic variability of human parvovirus B19, the complete coding region of the VP1/VP2 structural proteins of 29 B19 isolates obtained from 25 infected patients were sequenced and compared with each other and with two previously published B19 isolates. The VP1/VP2 gene was amplified by PCR using B19-specific oligonucleotide primers and the amplification products were sequenced directly. Overall, the average nucleotide and predicted amino acid identity among B19 isolates was high. Sequential virus isolates from the same cases and isolates obtained from two cases linked by transmission in the same household were essentially identical. Sequence variation was minimal among isolates obtained from a single community-wide B19 outbreak, ranging between 0 and 10 (0.4%) base substitutions, although there appeared to be more than one genetic lineage circulating in the outbreak. A comparison with 18 additional isolates from distinct epidemiological settings found greater variability. These isolates differed from each other by between 11 (0.5%) and 112 (4.8%) base substitutions. B19 isolates from Xi'an, China, were significantly different from other isolates at both the nucleotide and amino acid levels, and were more closely related to a single isolate from Japan, obtained 10 years earlier, than to isolates from other countries. Isolates examined in this study included distinct genotypes from patients with similar clinical presentations and similar genotypes from patients with diverse clinical presentations. These data suggest that geographically defined genetic lineages of B19 may exist and that no particular B19 genotype was associated with a particular clinical outcome.

Adolescent↗
PubMed1995

Development and evaluation of capture immunoglobulin G and M hemadherence assays by using human type O erythrocytes and recombinant parvovirus B19 antigen.

The capacity of human parvovirus B19 to agglutinate human type O erythrocytes was used to develop immunoglobulin G and M antibody capture hemadherence assays. When results of these assays were compared with those of corresponding antibody capture enzyme immunoassays using a well-characterized panel of 125 serum specimens, a 96.8% overall agreement was obtained between the two methods.

ABO Blood-Group System↗
PubMed1994

The influence of vasectomy and vasovasostomy on testicular ATPases, cAMP, ABP and androgen receptor in rabbits.

The present study was performed to further clarify the influences of vasectomy on functions of testis and to disclose the possible mechanisms of infertility after vasovasostomy (VV). Thirty-one rabbits were divided into sham-operated control group (C), vasectomy control group (V), VV fertility group (VaF) and VV infertility group (VaI). Serum testosterone (ST) level, testicular cAMP, androgen binding protein (ABP), nuclear androgen receptor (NAR) concentrations, testis cell membrane Na(+)-, K(+)-ATPase, Mg(2+)-ATPase activities, sperm density and testis weight were measured. Vasectomy resulted in significantly reduced cAMP, Na(+)-, K(+)-ATPase, Mg(2+)-ATPase, testis weight and increased ABP; VV completely restore testis weight in VaF and VaI, Na(+)-, K(+)-ATPase, Mg(2+)-ATPase in VaF, partly cAMP in VaF and VaI, Na(+)-, K(+)-ATPase, Mg(2+)-ATPase in VaI, but did not restore ABP. The NAR content in VaI was significantly lower than those in C, VaF and V. No statistical differences among 4 groups were seen in Kd values for [3H]-T. ST levels in VaF, VaI and V were insignificantly different compared with C, but the value in VaF was higher than that in VaI (p < 0.05). Sperm density after VV reached 122 +/- 62 x 10(6)/ml in VaF and 10 +/- 24 x 10(6)/ml in VaI, both in VaF and VaI were significantly low compared with C (p < 0.001), and the value in VaI was remarkedly lower than that in VaF (p < 0.001). It was shown that sperm density was positively correlated with cAMP content, Na(+)-, K(+)-ATPase, Mg(2+)-ATPase activities, but negatively with ABP. These results suggest that vasectomy gives rise to damage to the testis, and vasovasostomy does not appear completely effective in reversing testicular changes.

Adenosine Triphosphatases↗
PubMed1992

Prenatal diagnosis of intrauterine infection with parvovirus B19 by the polymerase chain reaction technique.

Human parvovirus B19 is a recently recognized cause of fetal hydrops and death. Efforts to characterize the natural history of fetal infection with this virus have been hampered by the lack of sensitive and specific tests for diagnosis in utero. Using the highly sensitive polymerase chain reaction (PCR) assay, we determined the fetal infection status in 56 pregnancies by testing amniotic fluid, fetal serum, and maternal serum for B19 DNA and antibodies. Factors associated with a high risk of B19 infection were fetal disease, exposure to persons with erythema infectiosum, or signs or symptoms of acute B19 infection. Fifteen women (27%) were B19 IgM-positive, a status suggesting recent infection; the positivity of all of the corresponding fetal specimens for B19 DNA in the PCR was indicative of fetal infection. In four of these cases, serial ultrasonographic examinations documented spontaneous resolution of fetal hydrops. Twenty-four women (43%) were IgG-positive and IgM-negative; this pattern suggested prior infection. The PCR gave positive results, consistent with recent maternal infection, in four of these cases. Seventeen women (30%) were IgG-negative and IgM-negative, a pattern suggesting no prior infection; the PCR results in four cases were indicative of a possible early maternal infection or a possible atypical immune response. The PCR is a sensitive and rapid method for the diagnosis of intrauterine infection with human parvovirus B19 and promises to facilitate studies of the natural history and treatment of this infection.

Adolescent↗
PubMed1992

Duck hepatitis B virus infection and duck hepatocellular carcinoma.

To study the relationship between duck hepatitis B virus (DHBV) infection and duck hepatocellular carcinoma (DHCC), histological examination and DHBV DNA hybridization were performed in 875 ducks from three flocks in Qidong County. Among them, 34 suffered from hepatoma, including 23 hepatocellular carcinoma, 8 cholangiocarcinoma and 3 hepatocellular-cholangiocarcinoma. Of the 34 ducks with hepatoma 27 were positive for DHBV DNA in the liver and/or serum. DHBV DNA was demonstrated in neoplastic nodules of 22 ducks. Southern blot analysis showed that 13 cases were of the integrated pattern of DHBV DNA in neoplastic nodules. The paratumor tissues of 14 ducks with massive tumor were analysed at the same time. Five cases showed integrated pattern, 4 cases free pattern and the other 4 cases both integration and free pattern of DHBV DNA. The hybridization pattern of DHBV DNA in tumor nodule was different from that in paratumor regions in 11 cases and identical in 3 cases. DHBV antigen was positive in 13 tumor nodules and 21 paratumor tissues in the 34 ducks with hepatic tumor by both victoria blue and orcein stain methods. Advanced liver diseases were found in 30 out of the 34 ducks with hepatoma, including 12 cirrhosis and 18 chronic active hepatitis. In southern blot analysis of 122 DHBV DNA positive Qidong ducks without hepatoma, only free pattern of DHBV was seen, while 44 control ducks from Changchun were negative for DHBV DNA. Neither hepatic tumor nor liver diseases were seen in the control ducks. The results suggest that hepatocellular carcinoma in ducks is similar to that in human HCC. They have a high frequency of viral DNA integrated into the host genome and a liver disease background.

Animals↗
PubMed1990

[Hepatitis D virus RNA in serum from patients with hepatitis B].

To clarify the correlation of hepatitis D virus (HDV) infection and viral replication in liver diseases, the authors detected HDV RNA and serological HDV markers in serum from 285 patients with hepatitis B and 45 asymptomatic carriers of HBsAg. With dot blot hybridization, serum HDV RNA was detected in 8.8% (29/330) of the patients with HBV infection. The positive rate of HDV RNA in fulminant hepatitis was higher than that in benign hepatitis (15/74 vs 3/47, P less than 0.05). 10 of the 139 patients with chronic active hepatitis and 1 of the 6 cases with cirrhosis were positive for HDV RNA. However, all of the 19 cases with chronic persistent hepatitis and 45 asymptomatic carriers of HBsAg were negative fo, HDV RNA. Serological HDV markers, HDAgr anti-HD and IgM-anti-HD, were determined with ELISA. HDV RNA was detected in all of the serum samples with positive HDAg and/or IgM-anti-HD, in 15 of the 26 cases with positive-anti-HD and in 8 cases without HDV markers. Our results showed that 40 of the 330 patients with HBsAg were infected by HDV. This investigation suggests that HDV is one of the etiological factors for fulminant hepatitis and chronic active hepatitis.

Adolescent↗
PubMed1989

[Clinical significance of the relation of primary or secondary hepatic ducts and their surrounding vessels].

It is necessary that surgeons, who perform the operation on the primary and secondary hepatic ducts, should be familiar with the topography of these ducts and their surrounding vessels. A total of 22 "frame-specimens" of cadaveric liver (FSL) were built by the authors, from which the length of left and right hepatic ducts (LHD, RHD), right anterior lobe duct (RAD), the distance from the confluence of RAD and right posterior lobe duct (CAP) to the visceral surface of the liver, and the projection point of CAP on the diaphragmatic surface of Liver were all directly measured. The relationship between these proximal hepatic ducts and their surrounding vessels was also observed. Based on this study the authors proposed a new approach to incision of the whole length of LHD, RHD and RAD. The stenotic opening of right posterior lobe duct (RPD) can be exposed through the lumen of RHD. In 18.2% of 22 FSLs, the right posterior lobe artery was found in the lateral angle formed by RAD and RPD. To prevent the damage of this artery, which may cause intrahepatic hematoma, and its rupture into biliary tract, the cholongiotomy incision at the stenotic opening of RPD should be made within the lateral-superior quadrant of it close to the horizontal level.

Adult↗
PubMed1985

New concepts in severe presacral hemorrhage during proctectomy.

In the past, surgeons thought that severe presacral hemorrhage during proctectomy was caused by damage of the presacral venous plexus. By studying the anatomy and clinical data, we found that injury of the sacral basivertebral vein also caused this serious complication. Presacral hemorrhage is seen as massive bleeding from the distal pelvic surface of sacrum or from one to several large-caliber foramina of sacral basivertebral veins in that area. This type of presacral hemorrhage is more dangerous than that from simple injury of presacral venous plexus and sometimes it is fatal. We describe the anatomic features of the vertebral venous system and its close relationship with severe presacral hemorrhage. We also propose some new concepts about cause, hemostatic measures, and principles of prevention.

Adult↗