Biomedical subjects

P H Zhang

Publications and source records attributed to P H Zhang.

At least 19 recordsLinked to original sources

PubMed2006

Sequence variations in the MBL gene and their relationship to pulmonary tuberculosis in the Chinese Han population.

SETTING: The mannan binding lectin (MBL) gene is thought to play a role in human innate immune response to tuberculosis (TB) infection. OBJECTIVE: To investigate the possible association between MBL sequence variants and TB infection in the Chinese Han population. DESIGN: A total of 152 male pulmonary tuberculosis (PTB) patients and 293 healthy male subjects were recruited. Six MBL single nucleotide polymorphisms (SNPs) (A/B, A/C, A/D, H/L, Y/X and P/Q) were genotyped and haplotyped using the combined analysis of polymerase chain reaction using sequence-specific primers (PCR-SSP) and the PCR-sequence specific oligonucleotide probe (PCR-SSOP) assay. The genotype and haplotype frequencies were compared between TB cases and controls using an unconditional logistic regression model. RESULTS: Neither the genotypes nor the haplotypes of the five loci were significantly associated with the disease when considered individually. After the haplotypes were regrouped, however, the XB haplotype group coding for diminished MBL levels was present at a significantly higher frequency in the patients compared with the YA group (OR 1.57, 95% CI 1.02-2.41, P < 0.05). CONCLUSION: No convincing evidence of association between MBL sequence variants and PTB was observed individually, although the low-producing XB haplotype group may serve as a minor risk factor for PTB infection in the male Chinese Han population.

Adolescent↗

PubMed2004

VDR and NRAMP1 gene polymorphisms in susceptibility to pulmonary tuberculosis among the Chinese Han population: a case-control study.

OBJECTIVE: To explore the potential role of vitamin D receptor (VDR) gene and natural-resistance-associated macrophage protein 1 (NRAMP1) gene polymorphisms in susceptibility to pulmonary tuberculosis (PTB) in the Chinese Han population. DESIGN: In an unmatched case-control study, 120 well defined PTB patients and 240 unrelated normal controls were enrolled. Information on potential risk factors of PTB was collected using a standard questionnaire. Genetic polymorphisms of VDR gene (TaqI and FokI) and NRAMP1 gene (INT4, D543N and 3'UTR) were analysed using PCR and RFLP. Unconditional logistic regression was performed, and odds ratios (ORs), their 95% confidence intervals (CI) and P values were estimated using maximum likelihood methods. RESULTS: Univariate analysis demonstrated that FokI-ff homozygotes, D543N G/A and 3'UTR TGTG+/del heterozygotes occurred more frequently in patients than in controls. The crude ORs were 2.345 (95%CI 1.222-4.499), 2.590 (95%CI 1.043-6.434) and 1.890 (95%CI 1.171-3.051), respectively, compared with their corresponding common genotypes. The P values were 0.033, 0.041 and 0.030, respectively. After adjusting for exposure history and BCG immunisation in the multivariate analysis, the adjusted ORs were 4.625 (95%CI 1.737-12.312), 2.415 (95%CI 1.079-8.759) and 2.187 (95%CI 1.146-4.175), with P values of 0.002, 0.036 and 0.018, respectively. Neither univariate nor multivariate analysis disclosed any significant association between the disease and TaqI or INT4. CONCLUSIONS: Polymorphisms in the VDR and NRAMP1 gene are statistically associated with susceptibility to PTB in the Chinese Han population.

Adult↗

PubMed2001

[Detection of anti-Spirometra erinaceieuropaei antibody using ELISA].

OBJECTIVE: To study specific diagnosis of Spirometra erinaceieuropaei. METHODS: An enzyme-linked immunosorbent assay (ELISA) was studied using highly pure gene engineering antigen expressed by the recombination of the cloned cysteine proteinase gene of Spirametra erinaceieuropaei with expression vector pMAL-c2. Six sera from patient infected with Spirometra erinaceieuropaei were detected using this method. RESULTS AND CONCLUSION: The results showed that the gene engineering antigen reacted strongly with the sera from Spirometra erinaceieuropaei-infected patients, but did not with the sera from Cysticercus cellulosae-infected patients.

Animals↗

PubMed2000

Granulocytic Ehrlichiae in Ixodes persulcatus ticks from an area in China where Lyme disease is endemic.

A total of 372 adult Ixodes persulcatus ticks were collected from vegetation in a forest area of Heilongjiang Province in northeastern China, where Lyme disease is known to be endemic. The ticks were examined for the presence of granulocytic ehrlichiae by heminested PCR with primers derived from the 16S rRNA gene. Of 310 ticks obtained from the Dahe forestry farm, two pools (each containing 5 ticks) were found positive, with a minimum infection rate of 0.6%. Ehrlichial DNA was also detected in one female (1.6%) of 62 ticks collected from the Yulin forestry farm. The overall minimum infection rate of the 372 I. persulcatus adults was 0.8%. The nucleotide sequences of 919-bp PCR products from the three positive tick specimens were identical to each other and very closely related to the members of the Ehrlichia phagocytophila genogroup. This is the first identification of granulocytic ehrlichiae in ticks in Asia and the first report of infection in I. persulcatus anywhere.

Animals↗

PubMed2000

Identification of Ehrlichia chaffeensis by nested PCR in ticks from Southern China.

A total of 717 ticks collected from southern China were examined by nested PCR for the presence of Ehrlichia chaffeensis. Sixteen (55. 2%) of 29 adult Amblyomma testudinarium ticks and 28 (11.7%) of 240 adult and at least 4.2% of 215 nymphal (pooled specimens) Haemaphysalis yeni ticks tested positive. Four other species of ticks were negative. Selected positive amplicons were confirmed by DNA sequencing.

Animals↗

PubMed1999

[Experimental study of incompetency of deep vein of lower limb].

OBJECTIVE: The purpose of this study was to find the best material for valvular wrapping operation of deep vein of lower limb and to study the diagnostic value of colored Ultrasonic-Doppler for valvular incompetency of the deep vein and the function of the popliteal valve. METHODS: Strips of autogenous saphenous vein, autogenous fascia lata and pieces of polytetrafluroethylene artificial vessel were used respectively as the wrapping material for narrowing the valve in 30 dogs. The results of three different wrapping material were obtained by colored Ultrasonic-Doppler and transpopliteal venography in 78 patients. The hemokinetics of the popliteal valve was examined in 20 normal persons. RESULTS: In the saphenous vein and fascia lata groups, diffuse fibrosis and marked narrowing of the femoral vein were found, while in the group of artificial vein graft, the graft was intact without prominent fibrosis and narrowing of the vein. In comparing with the result of venography, the accuracy of diagnosis by colored Ultrasonic-Doppler was 91.86%. The femoral and popliteal venous valves closed at the same time when holding the breath, but the popliteal venous valve opened more widely than the femoral venous valve when the calf muscles of the leg contracted. CONCLUSION: It was suggested that the graft was the best material for valvular wrapping operation, and colored Ultrasonic-Doppler was an important and non-invasive method for the diagnosis of incompetency of deep vein. The popliteal venous valve was the important barrier for protection of the function of deep vein.

Animals↗

PubMed1993

Experimental and clinical studies on one-stage arterialization of the venous channels for revascularization of severely ischemic limbs.

A new approach to perfuse arterial blood through venous channels for revascularization of severely ischemic limbs is reported. The procedure studied and used consists of creating an arteriovenous fistula between the normal arterial trunk proximal to the occlusion and the deep venous trunk of the diseased limb, constricting the venous trunk proximal to the anastomosis to one third of its lumen diameter, ligating the communicating and small tributary veins distal to the constriction in the operative field. The results of the experimental and clinical studies have shown that the treated ischemic limb was quickly revascularized without undesirable influence on cardiac function. This new approach has been used in the treatment of severe ischemia involving total 212 limbs in 156 patients, and the results appeared more satisfactory than those treated with staged arteriovenous reversal.

Adult↗

PubMed1991

Are the histidine residues of glutathione S-transferase important in catalysis? An assessment by 13C NMR spectroscopy and site-specific mutagenesis.

To test the proposition that a histidine residue is essential in the catalytic mechanism of glutathione S-transferase, rat liver isoenzyme 3-3 specifically labeled with [ring-2-13C]histidine was prepared. The 13C NMR spectrum of the labeled enzyme revealed four resonances corresponding to the 4 histidine residues in the mu gene class type 3 subunit. Titration of the four resonances in the range of pH 4-9 both in the presence and absence of glutathione gave pK alpha values of much less than 4, 5.2, 7.1, and 7.8 for the four side chains that were identified by site-specific mutagenesis as His14, His83, His84, and His167, respectively. The magnetic resonance properties and titration behavior of His14 suggest that this residue is buried in a hydrophobic environment. Conservative replacement of each histidine with asparagine results in mutant enzymes that have catalytic properties very close to the native protein as assessed with three different substrates, 1-chloro-2,4-dinitrobenzene, 4-phenyl-3-buten-2-one, and phenanthrene 9,10-oxide. The results indicate clearly that none of the histidine residues of isoenzyme 3-3 is essential for stabilization of the bound glutathione thiolate or for any other aspect of catalysis.

Animals↗

PubMed1991

Investigation of Lyme disease in Xinjiang.

From April through July 1988, an epidemiological investigation on Lyme disease was carried out in Nalati Xanyuan, Xinjiang Uygur Autonomous Region, China. Of 150 Ixodes persulcatus ticks examined by darkfield microscopy, 42 (28%) were found to have spirochetes. Two strains of spirochetes were isolated from I. persulcatus with BSK medium. Rabbits inoculated with the spirochetes showed erythema chronicum migrans at the sites of inoculation and the spirochetes were found in the cerebrospinal fluid by darkfield microscopy. Serum samples from 63 patients were examined for antibodies to B. burgdorferi by IFA test and 11 of them were positive with a titer of 1:64. Upon these results, it may be concluded that natural focus of Lyme disease exists in Xinjiang, China.

Animals↗

PubMed1990

Construction, expression, and preliminary characterization of chimeric class mu glutathione S-transferases with altered catalytic properties.

An expression plasmid for isoenzyme 3-3 of rat liver glutathione S-transferase has been constructed from the cDNA clone pGTA/C44 and the pAS expression vector pMG27NS, and used for the efficient production of the enzyme in the Escherichia coli strain M5219. The plasmid has also been manipulated, through the use of synthetic linkers, to encode chimeric polypeptides in which short sequences of the closely related isoenzyme 4-4 have been substituted into the N-terminal and C-terminal variable domains of isoenzyme 3-3. The chimeric polypeptides designated 4(9)3(208), 3(209)4(8), and 4(9)3(200)4(8) are expressed with varying degrees of efficiency in E. coli. The active dimeric holoenzymes 3-3, (4(9)3(208]2, (3(209)4(8]2, and (4(9)3(200)4(8]2 can be isolated. The spectroscopic and kinetic properties of the chimeric enzymes are significantly different than the native enzyme.

Amino Acid Sequence↗

PubMed1990

Clinical study of late-stage postthrombotic lower extremities.

Through clinical and venographic study of 353 diseased limbs, the authors advocate a new classification for the postthrombotic syndrome of the deep veins of the lower extremity. The postthrombotic lower extremities may be divided into two types: (1) lesions of the whole lower extremity, consisting of the completely obstructed, partially recanalized, and completely recanalized types; (2) local lesions, such as segmental obstruction of the iliac, iliofemoral, superficial femoral, femoropopliteal veins, and the tibioperoneal venous trunk and the venous plexus in calf muscles. Each type has its characteristics related to the duration of symptoms and clinical features, and their management is not the same at all. The authors suggest that clinically this new classification may be of great help in estimating the status of the diseased limb and in selecting proper method of treatment.

Female↗

PubMed1989

Formation of the 1-(S-glutathionyl)-2,4,6-trinitrocyclohexadienate anion at the active site of glutathione S-transferase: evidence for enzymic stabilization of sigma-complex intermediates in nucleophilic aromatic substitution reactions.

Formation of the Meisenheimer complex or sigma-complex [1-(S-glutathionyl)-2,4,6-trinitrocyclohexadienate] between glutathione (GSH) and 1,3,5-trinitrobenzene (TNB) can be observed at the active sites of isoenzymes 3-3 and 4-4 of rat liver GSH transferase. The spectroscopic properties (UV-visible and CD) of the enzyme-bound sigma-complex are consistent with a 1:1 complex in an asymmetric environment. Competitive inhibitors which occupy the GSH binding site (e.g., gamma-L-glutamyl-D,L-2-aminomalonylglycine) inhibit sigma-complex formation. The apparent formation constants of the sigma-complex (M) with enzyme-bound GSH (E.GS- + TNB in equilibrium E.M) at pH 7.5 are 5 x 10(4) M-1 and 7 x 10(2) M-1 for isoenzymes 3-3 and 4-4, respectively. Both values are much greater than that in aqueous solution (GS- + TNB in equilibrium M), where Kf = 28 M-1. Isoenzyme 3-3 is roughly an order of magnitude more efficient than 4-4 in catalyzing nucleophilic aromatic substitutions, a fact that appears to correlate with the ability of each enzyme to stabilize the sigma-complex. The pH dependence of Kf(app) for isoenzyme 3-3 is used to probe the ionization behavior of enzyme-bound GSH. The results are consistent with a double-ionization scheme (e.g., H+E.GSH in equilibrium H+E.GS- in equilibrium E.GS-) with pK's of 5.7 and 7.6, which are assigned to the thiol pK and the pK of a protonated base in the active site, respectively. Formation of the sigma-complex is also observed in single crystals of isoenzyme 3-3, providing a clear demonstration of the chemical competence of the crystallized enzyme. The results are discussed with respect to catalytic efficiency and the ability of the enzyme to stabilize sigma-complex intermediates in nucleophilic aromatic substitution reactions.

Animals↗

PubMed1988