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Z H Yang

Publications and source records attributed to Z H Yang.

At least 19 recordsLinked to original sources
PubMed2006

Association between Mycobacterium tuberculosis Beijing/W lineage strain infection and extrathoracic tuberculosis: Insights from epidemiologic and clinical characterization of the three principal genetic groups of M. tuberculosis clinical isolates.

Clinical strains of Mycobacterium tuberculosis can be divided into three principal genetic groups based on the single-nucleotide polymorphisms at the katG gene codon 463 and the gyrA gene codon 95. One subgroup of genetic group 1, the Beijing/W lineage, has been widely studied because of its worldwide distribution and association with outbreaks. In order to increase our understanding of the clinical and epidemiological relevance of the genetic grouping of M. tuberculosis clinical strains and the Beijing/W lineage, we investigated the genetic grouping of 679 clinical isolates of M. tuberculosis, representing 96.3% of culture-confirmed tuberculosis cases diagnosed in Arkansas between January 1996 and December 2000 using PCR and DNA sequencing. We assessed the associations of infections by different genetic groups of M. tuberculosis strains and infection by the Beijing/W lineage strains with the clinical and epidemiological characteristics of the patients using chi-square tests and multivariate logistic regression analysis. Of the 679 study isolates, 676 fell into one of the three principal genetic groups, with 63 (9.3%) in group 1, 438 (64.8%) in group 2, and 175 (25.9%) in group 3. After adjusting for potential confounding of age, gender, race/ethnicity, human immunodeficiency virus serostatus, and plcD genotype in a multivariate logistic regression model, patients infected by the Beijing/W lineage isolates were nearly three times as likely as patients infected with the non-Beijing/W lineage isolates to have an extrathoracic involvement (odds ratio [95% confidence interval], 2.85 [1.33, 6.12]). Thus, the Beijing/W lineage strains may have some special biological features that facilitate the development of extrathoracic tuberculosis.

Adolescent↗
PubMed2006

Population-based study of deletions in five different genomic regions of Mycobacterium tuberculosis and possible clinical relevance of the deletions.

Regions of difference (RDs) have been described in clinical isolates of Mycobacterium tuberculosis, but the potential epidemiological and clinical relevance of the genotypes of these RDs remains to be investigated. We screened a population-based sample of 648 isolates for the deletion of five RDs, designated RD105, RD181, RD142, RD150, and RD239, using microarray-based hybridization, PCR, and DNA sequencing and assessed the associations between the RD deletions and the clinical characteristics of the patients using chi-square analysis and multivariate logistic regression model. Of the 648 isolates, 18 (2.8%) had the RD239 deletion and 39 (6.0%) had the RD105 deletion. The deletions of RD142, RD150, and RD181 subdivided the isolates with the RD105 deletion into four groups comprising a group with concurrent deletions of RD105, RD181, and RD142 (n = 13); a group with concurrent deletions of RD105, RD181, and RD150 (n = 5); a group with concurrent deletions of RD105 and RD181 (n = 13); and a group with a deletion of RD105 only (n = 8). Extrathoracic tuberculosis is statistically significantly associated with infection with the isolates with concurrent deletions of RD105, RD181, and RD142 (adjusted odds ratio [OR] = 3.05; 95% confidence interval [CI] = 1.58, 5.90) and the isolates with concurrent deletions of RD105, RD181, and RD150 (adjusted OR = 11.09; 95% CI = 4.27, 28.80), after controlling for the previously identified risk factors for extrathoracic tuberculosis (human immunodeficiency virus serostatus, race, gender, and the genotype of the plcD gene). These two combinations of RD deletions have the potential for predicting the clinical presentation of M. tuberculosis infection in the human host.

Adolescent↗
PubMed2005

Distribution of insertion- and deletion-associated genetic polymorphisms among four Mycobacterium tuberculosis phospholipase C genes and associations with extrathoracic tuberculosis: a population-based study.

The Mycobacterium tuberculosis genome contains four phospholipase C (PLC)-encoding genes, designated plcA, plcB, plcC, and plcD, respectively. Each of the four genes contributes to the overall PLC activity of M. tuberculosis. PLC is hypothesized to contribute to M. tuberculosis virulence. Infection of M. tuberculosis strains carrying a truncated plcD gene is associated with the occurrence of extrathoracic tuberculosis. However, whether the other three plc genes are also associated with extrathoracic tuberculosis remains to be assessed. We investigated the insertion- and deletion-associated genetic diversity in all four plc genes among 682 epidemiologically and clinically well-characterized M. tuberculosis clinical isolates using PCR, DNA sequencing, and Southern hybridization. Two hundred sixty-six (39%) of the 682 isolates had an interruption in at least one of the four plc genes, most often associated with an IS6110 insertion. The plcD gene interruption was the most common: it was observed in 233 (34%) of the isolates, compared to 4.7%, 4.1%, and 5.9% for plcA, plcB, and plcC gene interruption, respectively. The association between the plc gene genotypes and disease presentation was adjusted for clustering using generalized estimating equations for both bivariate and multivariate analyses. After controlling for the genotypes of the plcABC genes and the host-related risk factors, interruption in the plcD gene remained significantly associated with extrathoracic tuberculosis (odds ratio, 3.27; 95% confidence interval, 1.32 to 8.14). The data suggest that the plcD gene might play a more important role in the pathogenesis of thoracic TB than it does in the pathogenesis of extrathoracic TB.

Bacterial Proteins↗
PubMed2005

Epidemiologic import of tuberculosis cases whose isolates have similar but not identical IS6110 restriction fragment length polymorphism patterns.

Isolates of Mycobacterium tuberculosis from patients with epidemiologic links frequently demonstrate identical IS6110 restriction fragment length polymorphism (RFLP) patterns (i.e., RFLP clustering) because they are infected with the same strain. Uncertainty arises with isolates that differ from one another by a few IS6110 hybridizing bands. During the period from 1 January 1996 to 31 December 1999, isolates from 585 tuberculosis (TB) cases were analyzed by RFLP, representing 98.2% of the 596 culture-positive TB cases reported in Arkansas during the study period. Of the 585 cases for which RFLP was available, 419 (71.6%) had an RFLP pattern with more than five copies of IS6110. Of the total 74 clusters, 48 comprised isolates with more than five copies of IS6110 and included 164 cases. Sixty-nine isolates with more than five copies of IS6110 comprising 16 clusters and 60 unique isolates were found to be similar to at least 1 other isolate (differing from it by one or two hybridizing bands). Among the 129 cases whose isolates were similar to other clustered or unique isolates, 16 cases were discovered with epidemiologic links: 14 (15.2%) were among the 92 cases with IS6110 RFLP patterns similar to those in clusters, and 2 (5.2%) were among the 37 unique cases that were similar to another unique case. The isolates from the epidemiologically linked patients shared common spoligotypes; all except one case shared common polymorphic GC-rich sequence (PGRS) patterns. Of the 129 patients whose isolates differed from another by one or two hybridizing IS6110 bands, 101 (78.3%) shared common spoligotypes and 87 (67.4%) shared common PGRS RFLP patterns.

Bacterial Typing Techniques↗
PubMed2001

Targeted overexpression of CCAAT/enhancer-binding protein-delta evokes enhanced gene transcription of platelet-derived growth factor alpha-receptor in vascular smooth muscle cells.

Platelet-derived growth factor (PDGF) is thought to play a significant role in various models of vascular remodeling, particularly in the early process of vascular diseases. Its action is mediated by its specific receptor, the PDGF receptor. The PDGF alpha-receptor (PDGFalphaR) plays an important role in the growth and proliferation of vascular smooth muscle cells (VSMCs), and its gene expression is thought to be regulated by several potential transcriptional nuclear factors. However, the detailed mechanisms of tissue-specific transactivation of the PDGFalphaR gene in VSMCs remain to be clarified. We have previously demonstrated that the rat PDGFalphaR gene contains an enhancer core sequence for CCAAT/enhancer-binding proteins (C/EBPs) in its promoter region, and we have also suggested that C/EBP-delta is the principal factor involved in the induction of tissue-specific transcriptional activity of the PDGFalphaR gene in VSMCs. To explore the definitive roles of C/EBP-delta protein on PDGFalphaR gene transcription in VSMCs, we developed C/EBP-delta transgenic rats by using a chimeric fusion gene of the mouse smooth muscle alpha-actin promoter and an entire coding region of rat C/EBP-delta cDNA. This report describes the first successful targeted overexpression of C/EBP-delta capable of inducing PDGFalphaR gene transcription and modifying cell proliferative activity to PDGFs. Targeted overexpression of C/EBP-delta evokes high levels of PDGFalphaR gene expression, susceptibility to VSMC growth, and proliferation of VSMCs to PDGFs. The results obtained reveal evidence of a new role and new functional significance of C/EBP-delta on VSMC growth via the PDGFalphaR during the process of vascular remodeling and atherosclerosis.

Animals↗
PubMed2001

Sex-linked hybrid sterility in a butterfly.

Recent studies, primarily in Drosophila, have greatly advanced our understanding of Haldane's rule, the tendency for hybrid sterility or inviability to affect primarily the heterogametic sex (Haldane 1922). Although dominance theory (Turelli and Orr 1995) has been proposed as a general explanation of Haldane's rule, this remains to be tested in female-heterogametic taxa, such as the Lepidoptera. Here we describe a novel example of Haldane's rule in Heliconius melpomene (Lepidoptera; Nymphalidae). Female F1 offspring are sterile when a male from French Guiana is crossed to a female from Panama, but fertile in the reciprocal cross. Male F1s are fertile in both directions. Similar female F1 sterility occurs in crosses between French Guiana and eastern Colombian populations. Backcrosses and linkage analysis show that sterility results from an interaction between gene(s) on the Z chromosome of the Guiana race with autosomal factors in the Panama genome. Large X (or Z) effects are commonly observed in Drosophila, but to our knowledge have not been previously demonstrated for hybrid sterility in Lepidoptera. Differences in the abundance of male versus female or Z-linked versus autosomal sterility factors cannot be ruled out in our crosses as causes of Haldane's rule. Nonetheless, the demonstration that recessive Z-linked loci cause hybrid sterility in a female heterogametic species supports the contention that dominance theory provides a general explanation of Haldane's rule (Turelli and Orr 2000).

Animals↗
PubMed2001

Secondary typing of Mycobacterium tuberculosis isolates with matching IS6110 fingerprints from different geographic regions of the United States.

Fifty-nine isolates of Mycobacterium tuberculosis obtained from different states in the United States and representing 25 interstate clusters were investigated. These clusters were identified by computer-assisted analysis of DNA fingerprints submitted during 1996 and 1997 by different laboratories participating in the CDC National Genotyping and Surveillance Network. Isolates were fingerprinted with the IS6110 right-hand probe (IS6110-3'), the IS6110 left-hand probe (IS6110-5'), and the probe pTBN12, containing the polymorphic GC-rich sequence (PGRS). Spoligotyping based on the polymorphism in the 36-bp direct-repeat locus was also performed. As a control, 43 M. tuberculosis isolates in 17 clusters obtained from patients in Arkansas during the study period were analyzed. Of the 25 interstate clusters, 19 were confirmed as correctly clustered when all the isolates were analyzed on the same gel using the IS6110-3' probe. Of the 19 true IS6110-3' clusters, 10 (53%) were subdivided by one or more secondary typing methods. Clustering of the control group was virtually identical by all methods. Of the three different secondary typing methods, spoligotyping was the least discriminating. IS6110-5' fingerprinting was as discriminating as PGRS fingerprinting. The data indicate that the IS6110-5' probe not only is a useful secondary typing method but also probably would prove to be a more useful primary typing method for a genotyping network which involves isolates from different geographic regions.

Bacterial Typing Techniques↗
PubMed2001

Inhibition of platelet aggregation of a mutant proinsulin molecule engineered by introduction of a native Arg-Gly-Asp sequence.

A 13 amino acid sequence, CRVARGDWNDNYC, originated from disintegrin eristostatin, was introduced into an inactive human proinsulin molecule between the B29 and A2 sites to replace proinsulin C-peptide by molecular cloning techniques. The constructed Arg-Gly-Asp (RGD)-proinsulin gene was cloned into a temperature-inducible vector pBV220 and expressed in Escherichia coli. The expressed RGD-proinsulin was refolded and purified by Sephadex G50 and DEAE-Sephadex A25 separations. The chemical identity was confirmed by both amino acid composition and mass spectrometry analyses. This RGD-proinsulin showed an inhibitory activity of adenosine 5'-diphosphate-induced human platelet aggregation with an IC50 value of 200 nM. Its insulin receptor binding activity remained as low as 0.03% with native insulin as a control, and its insulin immune activity retained 27.6% compared with proinsulin.

Adenosine Diphosphate↗
PubMed2001

A clinic-based molecular epidemiologic study of tuberculosis in Monterrey, Mexico.

SETTING: A tuberculosis clinic associated with a university hospital in Monterrey, Mexico, an urban community with high tuberculosis incidence. OBJECTIVE: To determine the diversity of DNA fingerprint patterns and the extent of drug resistance of Mycobacterium tuberculosis isolates from patients who attended the clinic. DESIGN: Isolates of M. tuberculosis obtained from 186 patients during the period from 31 January 1996 to 31 March 1998 were tested for susceptibility to isoniazid, rifampicin, ethambutol and streptomycin. Demographic data and the social history of each patient were obtained prospectively by interview. The IS6110 DNA fingerprints were obtained for 166 of the 186 isolates. Secondary typing was carried out on isolates with fewer than six copies of IS6110. RESULTS: Thirty-two per cent of the tested isolates (60/ 186) were drug-resistant, and 18% (33/186) were multidrug-resistant. Approximately 55% of the resistant isolates (33/60) were attributed to acquired resistance. A total of 106 different IS6110 fingerprint patterns were observed among the 166 fingerprinted isolates. Based on both IS6110 and pTBN12 fingerprinting, 65 (39%) of the 166 isolates were part of 22 DNA fingerprint clusters. Various drug susceptibility patterns were seen in most clusters. CONCLUSION: Fingerprint clustering indicates extensive recent transmission of tuberculosis in patients attending the clinic. The prevalence of drug-resistant tuberculosis is high.

Adult↗
PubMed2001

[Replantation of segmental destructive amputation of multiple fingers].

OBJECTIVE: To discuss the indication of replantation of destructive amputation of multiple fingers for improvement of the function of injured fingers. METHODS: From February 1996 to August 1999, 23 amputated fingers in 8 cases were shortened and replanted. The crushed digital bones were fixed by Kirschner wires, flexor tendons repaired by Kessler suture technique, and digital extensor tendons repaired by mattress suture. The arteries and veins were anastomosed in each finger at the ratio of 1 to 2 or 2 to 3. The defect of blood vessels was repaired by free graft of autologous veins in 5 fingers. All of the cases were followed up for 10 to 18 months, and clinical evaluation was performed. RESULTS: All replanted fingers survived in the 8 cases, with good sensation, two point discrimination of 6 to 12 mm, and satisfied function, such as pinching, grasping and hooking. The fingers were shortened for 2.6 cm in average, ranging from 2.2 cm to 4.0 cm. CONCLUSION: Multiple digits replantation by shortening fingers is beneficial to functional restoration of segmental destructive fingers.

Adolescent↗
PubMed2000

Spoligotyping and polymorphic GC-rich repetitive sequence fingerprinting of mycobacterium tuberculosis strains having few copies of IS6110.

Several genetic loci have been utilized to genotype isolates of Mycobacterium tuberculosis. A shortcoming of the most commonly used method, IS6110 fingerprinting, is that it does not adequately discriminate between isolates having few copies of IS6110. This study was undertaken to compare pTBN12 fingerprinting of polymorphic GC-rich repetitive sequence genes and spoligotyping of the direct repeat locus as secondary typing procedures for M. tuberculosis isolates having fewer than six copies of IS6110. A total of 88 isolates (100% of the isolates with fewer than six copies of IS6110 isolated in Arkansas during 1996 and 1997) were included in this study. Among the 88 isolates, 34 different IS6110 patterns were observed, 10 of which were shared by more than 1 isolate, involving a total of 64 isolates. The 64 isolates were subdivided into 13 clusters (containing 37 isolates) and 27 unique isolates based on a combination of IS6110 and pTBN12 fingerprinting and into 11 clusters (containing 51 isolates) and 13 unique isolates based on a combination of IS6110 fingerprinting and spoligotyping. Identical spoligotypes were found among isolates having different IS6110 patterns, as well as among isolates showing different pTBN12 patterns. In contrast, all isolates that had different IS6110 patterns were found to be unique by pTBN12 typing. The clustering rate was 73, 58, and 42%, respectively, for IS6110 fingerprinting alone, IS6110 fingerprinting and spoligotyping combined, and IS6110 and pTBN12 combined fingerprinting. The data indicate that the pTBN12 method has greater discriminating power among low-copy-number isolates than does spoligotyping.

Arkansas↗
PubMed2000

Efficacy of an unsupervised 8-month rifampicin-containing regimen for the treatment of pulmonary tuberculosis in HIV-infected adults. Uganda-Case Western Reserve University Research Collaboration.

SETTING: National Tuberculosis Treatment Centre, Mulago Hospital, Kampala, Uganda. OBJECTIVE: To assess the efficacy of a daily, self-administered 8-month rifampicin-containing regimen for the treatment of pulmonary tuberculosis (TB) in human immunodeficiency virus (HIV) infected adults. DESIGN: Treatment outcomes in patients with pulmonary TB treated with a single 8-month regimen and followed in a prospective epidemiological study. RESULTS: Two hundred and sixty-five HIV-infected and 26 non-HIV-infected adults with initial episodes of pulmonary tuberculosis were treated with 2 months of daily isoniazid (INH), rifampicin (RMP), ethambutol and pyrazinamide followed by 6 months of daily INH + RMP. Median follow-up was 17.8 months. Ninety-five per cent of the HIV-infected and all of the non-HIV-infected patients who had sputum examined were sputum culture negative after 2 months of treatment. Twenty-two HIV-infected and no non-HIV-infected patients died during treatment. Relapse rates were 8.4% (5.9 per 100 person-years of observation [PYO], 95%CI 3.2-8.6) among HIV-infected patients and 4.5% (2.1/100 PYO, 95%CI 0-7.8) for non-HIV-infected patients. Adverse drug reactions occurred in 37% of the HIV-infected patients; most were minor and self-limiting. CONCLUSION: An 8-month RMP-containing regimen was well tolerated and effective in the treatment of HIV-infected adults with initial episodes of pulmonary TB. Relapse rates were similar to those reported with 6-month short-course regimens in HIV-infected individuals. Decisions about the duration of anti-tuberculosis treatment for HIV-infected adults must balance programme resources and the likelihood of poor compliance with longer regimens with the potential for a modest decrease in relapses with longer treatment.

AIDS-Related Opportunistic Infections↗
PubMed2000

[Effects of chronic stress on the learning and memory ability and hippocampal LTP in rats].

AIM AND METHODS: A chronic stress model in 21 days with multi-stressors was applied to question the effects of stress on the learning and memory ability and the hippocampal neuronal synaptic plasticity in rats, using the Y maze test and LTP electrophysiological recording in vivo. RESULTS: The impairment of spatial learning and memory ability and an obvious suppression in LTP in hippocampal dentate gyrus was observed in stress group after chronic stress. CONCLUSION: The hippocampal synaptic plasticity may be decreased by the chronic stress. And then, the learning and memory ability may also be impaired consequently.

Animals↗
PubMed1999

Separation and characterization of trypsin and carboxypeptidase B-digested products of Met-Lys-human proinsulin.

Met-Lys-human proinsulin could be converted into insulin in vitro with the treatment of trypsin and carboxypeptidase B (CPB). Under less effective conditions, the enzymatic reaction does not proceed perfectly, and two main bands have been identified by native-polyacrylamide gel electrophoresis (PAGE) analysis. These two main products were thus separated and purified by DEAE-Sephadex A25 chromatography in a Tris-isopropanol system with an NaCl gradient. The isopropanol and NaCl were removed by a second DEAE-Sephadex column. Native-PAGE, mass spectrometric, and amino acid composition analyses indicate that one fraction of these two major products contains human insulin and desB30-insulin and that the other fraction is a mixture of human insulin analogs, which have one more basic amino acid than human insulin owing to the unsuitable amount of proteases, especially the lack of CPB. Furthermore, both receptor binding assay and radioimmunoassay have been utilized for the activity determination, and both fractions display almost full biological activity with porcine insulin as the standard. Present results provide further evidence for the quality control of recombinant human insulin production.

Amino Acids↗
PubMed1999

Selective effects of alfuzosin and doxazosin with intraduodenal administration on urethral pressure of cats.

AIM: To observe the selective effects of alfuzosin (Alf) and doxazosin (Dox) on the urethral pressure by different administration routes. METHODS: The urethral pressure of the anesthetized cat was increased by electric stimulation of the hypogastric nerve. The different effects of Alf or Dox on the arterial blood pressure and urethral pressure between intraduodenal administration (i.d.) and intravenous infusion (i.v.) were compared. RESULTS: When the hypogastric nerve was stimulated by electric stimulation (10 Hz, 25 V), the ratios of ED20(BP)/ED50(UP) i.d. to ED20(BP)/ED50(UP) i.v. were 10.9:4.3 for Alf, and 3.1:2.1 for Dox. The reduction in urethral pressure induced by i.d. Alf was greater than that by i.v. Alf. Dox did not show any difference in its effects by 2 administration routes. CONCLUSION: Intraduodenal administration of Alf, but not Dox, selectively decreased the urethral pressure elevated by electric stimulation. The uroselectivity of i.d. Alf was not due to the species difference in its bioavailability and biotransformation.

Adrenergic alpha-Antagonists↗
PubMed1999

External quality assessment survey for hematological laboratories in China.

To evaluate the feasibility of improving external quality assessment (EQA), we set up an experimental EQA survey that included 465 participants in China. During the period of this survey, we checked the quality of the EQA samples, divided the participants into different groups, each laboratory's result was assessed by calculation standard deviation index (SDI). The reference values were determined to evaluate the accuracy for peer groups. The data showed that the stability of the EQA samples was acceptable. Except for WBC count of the Abbott group, the mean, median and reference values for each parameter were very close. We found that the main reason affecting the performance of the participants was not using the reagents. calibrator and QC material recommended by manufacturer. From this survey, we obtain a good reference for future improvement.

Calibration↗
PubMed1997

The study of suicides in Chinese cities and rural areas.

"This paper studies the changes, trends, regularities, and characteristics of suicides committed by Chinese people based on statistical data and some investigative information from the government health department. From a sociological point of view, the author also analyzes the reasons for suicide in China and proposes some methods to reduce the suicide rate or avoid suicide."

Asia↗