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Biomedical subjects

G Q Zhang

Publications and source records attributed to G Q Zhang.

At least 37 records · Page 2Linked to original sources
PubMed1998

Clinical evaluation of a new PCR assay for detection of Coxiella burnetii in human serum samples.

A nested PCR method was developed for the detection of Coxiella burnetii in human serum samples. Two pairs of oligonucleotide primers were designed to amplify a 438-bp fragment of the com1 gene encoding a 27-kDa outer membrane protein of C. burnetii. The primers amplified the predicted fragments of 21 various strains of C. burnetii but did not react with DNA samples from other microorganisms. The 438-bp amplification products could be digested with restriction enzymes SspI and SalI. The utility of the nested PCR was evaluated by testing human serum samples. The com1 gene fragment was amplified from 135 (87%) of 155 indirect immunofluorescence test (IF)-positive serum samples and from 11 (11%) of 100 IF-negative serum samples. The nested PCR with primers targeted to the com1 gene appeared to be a sensitive, specific, and useful method for the detection of C. burnetii in serum samples.

Antibodies, Bacterial↗
PubMed1998

Direct identification of Coxiella burnetii plasmids in human sera by nested PCR.

Nested PCR assays were used for the direct identification of Coxiella burnetii plasmids in human sera. A total of 81 serum samples from 81 patients with Q fever were tested by nested PCR with four sets of primers. The first set of primers was used to detect the genomic sequences. The second set of primers was used to detect the conserved sequences of the plasmids. Another two sets of primers were used to identify the QpH1 and QpRS plasmids. QpH1 and QpRS plasmid-specific sequences were identified in 40 (49.4%) and 24 (29.6%) of the serum samples, respectively. Both of the QpH1 and QpRS plasmid-specific sequences were detected in 5 (8.6%) of the serum samples but were not found in 12 (20.7%) of the serum samples. Furthermore, all of the 23 acute-phase serum samples were positive for the QpH1 plasmid and negative for the QpRS plasmid. Nested PCR with plasmid-specific primers appears to be a useful method for the direct typing of C. burnetii plasmids in human sera.

Acute Disease↗
PubMed1998

Inhibitory effects of nimodipine on platelet aggregation and thrombosis.

AIM: To study the inhibitory effects of nimodipine (Nim) on rat platelet aggregation and arterial thrombosis in vivo. METHODS: The aggregation rate of platelets induced by ADP and inhibition rate of Nim were measured by the change of light transmission. Effect of Nim on arterial occlusion time was measured by electric stimulation. Effect of Nim on the contents of 6-keto-PGF1 alpha and TXB2 in serum was measured by radioimmunoassay. RESULTS: Nim 4.5, 9, 18, and 36 mg.kg-1.d-1 ig for 4 d restrained the platelet aggregation. The IC50 (95% confidence limits) was 26 (9-44) mg.kg-1. Nim 4.5, 9, and 18 mg.kg-1.d-1 ig for 4 d markedly prolonged the time of thrombotic occlusion in carotid artery induced by electric stimulation. Nim 9 and 18 mg.kg-1.d-1 improved the imbalance of 6-keto-PGF1 alpha/TXB2 in serum after thrombosis. CONCLUSION: Nim was a potent inhibitor of platelet aggregation, which was partially concerned with the improved balance of 6-keto-PGF1 alpha/TXB2.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

[Effects of doxepin on isolated basilar and saphenous artery rings of rabbits].

AIM: To study the effects of doxepin (Dox) on cerebral artery. METHODS: The effects of Dox were observed using the isolated basilar and saphenous artery rings of rabbits. RESULTS: Dox inhibited the constriction of the basilar and saphenous artery rings evoked by KCl with IC50 5.75 mumol.L-1 (95% confidence limits were 2.3-14 mumol.L-1, n = 8) and 34.6 mumol.L-1 (95% confidence limits were 3.8-316 mumol.L-1, n = 8), respectively. Dox also inhibited the constriction of the basilar and saphenous artery rings of the rabbits stimulated by 5-hydroxytryptamine (5-HT), IC50 were 6.3 mumol.L-1 (95% confidence limits were 1.7-23.3 mumol.L-1, n = 7) and 8.0 mumol.L-1 (95% confidence limits were 6.3-10.3 mumol.L-1, n = 6), respectively. In both samples (basilar and saphenous artery rings) CaCl2 evoked, the pD2 of Dox was 5.28 +/- 0.40 and 4.76 +/- 0.14, respectively (n = 6, P < 0.01). Dox 5.8 mumol.L-1 inhibited the constriction of the saphenous artery evoked by norepinephrine (NE) in Ca(2+)-free medium. Dox 30 mumol.L-1 inhibited the constriction of the saphenous artery evoked both by NE and by readmission of CaCl2 (1.25 mmol.L-1). CONCLUSION: As compared with its effect on the saphenous artery, Dox selectively inhibited the basilar artery.

Animals↗
PubMed1997

Differentiation of Coxiella burnetii by sequence analysis of the gene (com1) encoding a 27-kDa outer membrane protein.

The gene (com1) encoding a 27-kDa outer membrane protein in 21 strains of Coxiella burnetii from a variety of clinical and geographical sources was sequenced for strain differentiation. The com1 gene was highly conserved among all the strains tested but there were several differences in nucleotide and deduced amino acid sequences. Based on the com1 gene-specific nucleotides and deduced amino acids, the 21 strains were divided into four groups. Group 1 contained 14 strains originating from ticks, cattle and human cases of acute Q fever. Groups 2 and 3 included 2 and 3 strains, respectively, originating from human cases of chronic Q fever. Group 4 contained 2 strains originating from a human case of acute Q fever and a goat with abortion. The results indicated that the strains originating from ticks, cattle and human cases of acute Q fever differed at the molecular level from those of human chronic Q fever. This study suggests that a sequence analysis of the com1 gene can be used for strain differentiation of C. burnetii.

Amino Acid Sequence↗
PubMed1996

Rapid method for detection of Coxiella burnetii antibodies using high-density particle agglutination.

A high-density particle agglutination test, using erythrocyte-sensitizing substance from phase II Coxiella burnetii adsorbed to high-density composite particles, was developed for rapid serodiagnosis of Q fever. The test was compared with the microimmunofluorescence test for sensitivity and specificity by using 3,036 human serum samples collected in Gifu Prefecture, Japan. An excellent agreement was found between the two tests for the acute-phase group and paired serum samples, but some discordant results were observed in the single-sample group. The sensitivity and specificity of the high-density particle agglutination test were both 100% in the former group and 81.6 and 99.9%, respectively, in the latter group. The test is a very promising tool for routine serodiagnosis of Q fever because of its simplicity, sensitivity, and specificity.

Agglutination Tests↗
PubMed1996

Q fever pneumonia in children in Japan.

The prevalence of Q fever pneumonia among children with atypical pneumonia from whom only an acute-phase serum sample was available was traced by using an indirect immunofluorescence (IF) test, nested PCR, and isolation. Twenty (34.5%) of 58 sera were found to have both polyvalent and immunoglobulin M antibodies to the phase II antigen of Coxiella burnetii by the IF test. Q fever pneumonia was present in 23 (39.7%) of 58 patients as determined by both the nested PCR and isolation and in 20 patients as determined by the IF test. The sensitivities for nested PCR and isolation were 100%, and that for the IF test was 87%. Our results indicate that nested PCR was faster and more sensitive than isolation and the IF test in the diagnosis of acute Q fever when a single acute-phase serum was available. These findings suggest that C. burnetii is an important cause of atypical pneumonia in children in Japan.

Antibodies, Bacterial↗
PubMed1995

Isolation of Coxiella burnetii from dairy cattle and ticks, and some characteristics of the isolates in Japan.

Coxiella burnetii was isolated from raw milk (36/214, 16.8%) and uterus swab samples (13/61, 21.3%) originating from dairy cattle with reproductive disorders, aborted bovine fetus samples (2/4, 50%), mammary gland samples (4/50, 8%) originating from healthy dairy cattle, and tick samples (4/15, 26.7%) originating from 2 pastures. Fifty-nine strains had various degrees of pathogenicity, high (8; 13.6%), moderate (28; 47.5%) and low (23; 39%), for guinea pigs. The results of isolation suggested a high prevalence of Coxiella infection in dairy cattle with reproductive problems in Japan. Twelve strains (7, 2 and 3 strains from cattle, ticks and humans, respectively) and the reference Nine Mile strain of phases I and II were propagated in both yolk sacs of embryonated hen eggs and Buffalo green monkey (BGM) cell cultures. Protein profiles of these strains were similar to those of the reference strain of phase I. Lipopolysaccharide (LPS) profiles of 12 strains were similar to those of the reference strain of phase I and different from those of the reference strain of phase II. The LPS profiles of 12 strains suggested that these strains are associated with an acute form of Q fever.

Acute Disease↗
PubMed1995

[Studies on CDDP-albumin microspheres for hepatic arterial chemoembolization].

An optimum procedure was established by orthogonal test for preparing cis-platin albumin microspheres (CDDP-AMS) with emulsion-heating stabilization method. The factors which affect particle size and release rate in vitro were studied. The particle size focusing on 58.8-256 microns, the mean size was 148.46 microns, drug content was 51.16% (w/w). The dissolution profiles of the CDDP-AMS followed Higuchi kinetics. In rabbits the distribution and elimination half times of platinum were prolonged 3.36 times and 1.23 times vs injection group, respectively, after hepatic arterial chemoembolization with CDDP-AMS. The highest serum concentration of platinum is 30 percent of that of the injection group. The platinum concentration was increased in liver (P < 0.01) and decreased in kidney (P < 0.05) vs that of injection group.

Animals↗
PubMed1995

[Seroepidemiological study of HBV and HCV infection in sexually promiscuous groups].

A serological study on the detection of HBV and HCV infection markers and the investigation of related sexual behaviors were conducted among 431 female prostitutes and 109 normal women. The result showed of anti-HBc prevalence rate was 43.1% (186/431), anti-HBs positive rate was 36.9% (159/431), HBsAg positive rate was 11.1% (48/431) and anti-HCV positive rate 9.51% (41/431). They were all significantly higher in prostitutes than in normal women. The infection indexes of HBV and HCV were also higher in population with STD than in normal women. The prevalence of anti-HCV in female prostitutes tended to increase with increase of age. There was a significant correlation with the number of their clients and years of being prostitutes. This demonstrated that there was a relatively high HBV and HCV infection rates in prostitutes.

Adolescent↗
PubMed1994

Tissue and serum levels of steroid hormones and RU 486 after administration of mifepristone.

The present study was designed to examine the effect RU 486 administration on steroid hormone levels in serum and decidua. Sixty women at 6-7 weeks gestation were divided into three groups. The first group took a placebo 24 hours before interruption of pregnancy. The other two groups took 200 mg mifepristone 12 and 24 hours before the surgical procedure, respectively. The concentrations of steroids and mifepristone were measured by radioimmunoassay or high performance liquid chromatography. Mifepristone treatment increased the levels of estradiol, cortisol and testosterone in serum and decidual cytosol (p < 0.05 or p < 0.01). A minor elevation in progesterone level was observed but was not statistically significant. The tissue levels of progesterone, estradiol and testosterone were much higher than the serum levels, whereas RU 486 concentration in the tissue was only one-third of the serum level. In addition, the RU 486 level in decidual cytosol was of the same order as that of progesterone. This competitive concentration was not achieved in chorionic villi in our previous observation, explaining why mifepristone exerts its predominant effect on decidua rather than villi. It is concluded that RU 486 reached an effective inhibitory concentration in decidua and had significant effects on the endocrine milieu.

Abortion, Induced↗
PubMed1994

[Is there hepatitis C virus associated glomerulonephritis?].

Hepatitis C virus (HCV) infection is one of the important causes of chronic and severe hepatitis in China. In an attempt to understand if there is any relationship between HCV infection and glomerulonephritis (GN), serum samples from 570 GN patients and 100 normal volunteers were screened for anti-HCV antibody (HCV-Ab) with ELISA method. Among the cases with positive HCV-Ab, serum HCV-RNA was tested with nested RT-PCR method. The incidence of serum HCV-Ab was 2 in 100 normal volunteers (2%) and 34 in 570 GN patients (6%). The incidence of positive serum HCV-RNA was 0 in normal volunteers whereas 21 in GN patients. The main clinical manifestation of GN patients with serum positive HCV-Ab was an unique proteinuria with/without nephrotic syndrome or renal failure, whereas the pathologic lesions in GN patients with serum positive HCV-Ab or HCV-RNA consisted of different disease entities. There was no close link between MPGN and active HCV infection. From the data observed, it seems that there is a coincidence between glomerular diseases and HCV infection rather than a matter of cause and consequence.

Adolescent↗
PubMed1994

[Effects of high-level-manganese sewage irrigation on children's neurobehavior].

The neurobehavioral status was tested for 92 matched-pair pupils aged 11-13 in an area with high-level-manganese sewage irrigation and a control area. Results showed there was significant difference in manganese contents of drinking water between the area with sewage irrigation and the control area during 1990-1992, ranged 0.241-0.346 mg/L and 0.030-0.040 mg/L, respectively, with P < 0.01. Hair manganese content of children in the area with sewage irrigation (1.252 micrograms/g) was significantly higher than that in the control area (0.961 micrograms/g) with P < 0.01. Scores in digit span, Santa Ana manual dexterity, digit symbol, Benton visual retention test and pursuit aiming test for children in the area with sewage irrigation were significantly lower than those in the control area (P < 0.01). Hair manganese contents of the children in the area with sewage irrigation correlated negatively with most of those scores. It suggested high level of manganese in drinking water of the area with sewage irrigation might be an important factor affecting children's neurobehavioral changes.

Adolescent↗
PubMed1994

[Sequencing of hepatitis B virus DNA fragment coding major HBsAg of escape mutant].

We amplificated a HBV DNA fragment coding the major HBsAg from a chronic HBsAg carrier's serum with high titer of HBsAg and anti-HBs using polymerase chain reaction (PCR). The direct sequencing of PCR products revealed a single mutation from adnosine to guanosine at the nucleotide position 532 of HBV DNA of the escape mutant. This mutation might result in an amino acid substitution from threonine to alanime at the amino acid position 126 of HBsAg. Since this amino acid is located in the first loop of the "a" determinant of HBsAg, the mutation might result in an alteration of the structural antigenicity of the "a" determinant and induce escape mutant of HBV.

Antigenic Variation↗
PubMed1993

Pharmacokinetic study of RU 486 and its metabolites after oral administration of single doses to pregnant and non-pregnant women.

RU 486 and three of its metabolites (RU 42633-monodemethyl, RU 42848-didemethyl, and RU 42698-hydroxymetabolite) were determined by HPLC in plasma from nine non-pregnant and 36 pregnant women. Each non-pregnant subject took an oral dose of RU 486 (25, 100, 400 and 600 mg consecutively) once per menstrual cycle. Six of the nine women also received a dose of 200 mg. The 36 pregnant women were randomized into four groups which were given a single dose of 25, 100, 400 or 600 mg RU 486. Blood samples were taken up to 120 h after dosing. Peak concentrations of RU 486 occurred on most occasions within 2 h. Plasma concentrations at 1 h and at 24 h increased in proportion to log dose. There was a wide variability (up to ten-fold) in the pharmacokinetic parameters within each dose group. Plasma concentrations of RU 42633 were similar to those of RU 486 but concentrations of RU 42848 and RU 42698 were much lower. As with RU 486, the plasma concentrations of the metabolites were maintained at high levels for up to 48-72 h after dosing. The findings were consistent with a rapid metabolism of RU 486 to RU 42633; removal of the second methyl group leading to RU 42698 occurred much more slowly and to a much less extent than removal of the first. There appeared to be no significant differences between the non-pregnant and pregnant women in either the plasma concentrations or pharmacokinetic parameters of RU 486 and its metabolites.

Administration, Oral↗
PubMed1993

[A preliminary report on the prevalence of different types of hepatitis in adult patients with acute sporadic hepatitis in Beijing area].

In order to investigate the prevalence of different types of viral hepatitis in Beijing area, the markers of viral hepatitis A, B, C and E were detected on 72 adult patients with acute viral hepatitis in the infectious diseases department of our hospital. The results showed that 26.4% of the cases had HAV infection, 8.3% HBV infection, 18.1% HCV infection and 31.9% HEV infection. It is shown that the prevalence of HEV infection in Beijing area is high.

Acute Disease↗
PubMed1992

[Effects of imipramine on isolated rabbit basilar artery].

Imipramine (Imi) inhibited the contractile response to BAY k 8644 (IC50 = 2.39 +/- 0.33 mumol.L-1), KCl (IC50 = 1.00 +/- 0.09 mumol.L-1), in rabbit basilar artery rings. Imi was more effective in suppressing the contractile response evoked by KCl, CaCl2, and 5-HT in basilar artery rings than in mesenteric artery rings. The effect of Imi was the same as that of diltiazem (Dil). There was no difference between the inhibitory response of Imi on contraction induced by KCl in basilar artery rings with or without endothelium. The results suggest that Imi may block the calcium channel and inhibit the rabbit basilar artery selectively, and the effect is endothelium-independent.

Animals↗