Search PubMed⌕ Search

Biomedical subjects

Z Liang

Publications and source records attributed to Z Liang.

At least 127 records · Page 7Linked to original sources
PubMed1996

Half-dose aprotinin does not affect haemorheological properties in patients undergoing bypass surgery.

OBJECTIVE: To investigate haemorheological changes in patients undergoing coronary artery bypass grafting and to determine whether the protective effect on haemorheology of high-dose aprotinin also exists under a half-dose regimen. METHODS: Forty patients were studied in a double-blind, placebo-controlled study design. Patients in the aprotinin group received half of the standard high dose of aprotinin during surgery. Erythrocyte and white-cell clogging rates as well as whole blood and plasma viscosity were measured. Viscosity results were expressed as a ratio to the viscosity of saline. RESULTS: Erythrocyte and white-cell clogging rates were increased significantly, whereas whole blood and plasma viscosity were decreased significantly during cardiopulmonary bypass. The reduction in viscosity had a strong correlation to haemodilution. There was no significant difference in any of the measured variables between the aprotinin and the placebo groups. CONCLUSION: This study showed that blood cell damage occurred during cardiopulmonary bypass surgery, as measured by a raised clogging rate. This tendency was the same in both groups and therefore no increased potential for microthrombi could be attributed to aprotinin haemorheologically. However, half-dose aprotinin did not show any preserving effect in haemorheology when the blood-cell clogging rate and blood viscosity were studied.

Aged↗
PubMed1996

[Experimental study on the mechanism of cisplatin resistance and its reversion in human ovarian cancer].

OBJECTIVE: To explore the mechanism of cisplatin resistance and its reversion in human ovarian cancer. METHODS: A xenografted cisplatin resistant mice model of human ovarian cancer, SKOV3/cp, was developed by the microencapsulated technique. The multiple changes of bio-chemical markers in the model were determined, and various modulators for reversion were tested. RESULTS: Intracellular platinum accumulation in SKOV3 was 5.1 times, Pt-DNA adducts 2.4 times and interstrand cross link of DNA (ISC) 4.8 times of those in cisplatin-resistant cell line, SKOV3/cp. These changes in SKOV3/cp could not be reversed by verapamil. Amphotercin B (AmB) and Novobiocin (NVB) could raise the concentrations of platinum and Pt-DNA adducts in SKOV3/cp, resulting in complete or partial reversion of cisplatin-resistance of SKOV3/cp. There were no differences in total glutathione (GSH) level and in sensitivity to CdCl2 between SKOV3 and SKOV3/cp. CONCLUSIONS: It is suggested that the primary factor causing SKOV3/cp resistance to cisplatin is the reduction of intracellular platinum accumulation and the augmentation of the ability to remove Pt-DNA adducts. The resistance is not considered to be associated with the multidrug resistant, GSH, metallothionein systems. AmB and NVB can overcome cisplatin resistance of SKOV3/cp in vitro and in vivo.

Amphotericin B↗
PubMed1996

Secretory expression of a single-chain insulin precursor in yeast and its conversion into human insulin.

A synthetic single-chain porcine insulin precursor (PIP) gene and an alpha-mating factor leader sequence (alpha MFL) gene obtained by the PCR method are inserted between the promoter and 3'-terminating sequence of the alcohol dehydrogenase gene ADH1 in plasmid pVT102-U to form plasmid pVT102-U/alpha MFL-PIP. The single-chain insulin precursor is expressed and secreted to the culture medium by Saccharomyces cerevisiae transformed by pVT102-U/alpha MFL-PIP. The precursor is purified and converted into human insulin by tryptic transpeptidation. The purified human insulin is fully active and can be crystallized. The overall yield of human insulin is 25 mg per liter of culture medium.

Base Sequence↗
PubMed1996

Internal migration in China, 1950-1988.

This paper examines the long-term patterns of migration within China between 1950 and 1988. The analysis uses data from China's 1988 2/1,000 Fertility and Birth Control Survey, which asks respondents about their most recent interprovincial move. The results suggest that long-term migration patterns can be explained by political and economic changes in China. We argue that the approaches we introduce can offer significant insight into long-term migration patterns for countries where historical data on migration are unavailable or unreliable.

China↗
PubMed1996

Experimental study on the mechanism of cisplatin resistance and its reversion in human ovarian cancer.

OBJECTIVE: To explore the mechanism of cisplatin resistance and its reversion in human ovarian cancer. MATERIALS AND METHODS: A cisplatin resistant cell subline of SKOV3, SKOV3/cp, was established, and a xenograft mice model of human ovarian cancer was established by microencapsulation technology. Various biochemical changes and the effects of modulators on the resistance in the model were observed. RESULTS: The intracellular platinum accumulation. Pt-DNA adducts and interstrand cross links of DNA (ISC) in SKOV3 was 5.1, 2.4 and 4.8 times respectively of those in SKOV3/cp cell line. Amphotericin B (AmB) and Novobiocin (NVB) could raise platinum accumulation and Pt-DNA adducts concentration in SKOV3/cp and this resulted in reversion of cisplatin resistance. CONCLUSIONS: The primary factors resulting in SKOV3/cp resistance to cisplatin are the reduction of intracellular drugs and the augmentation of the ability to remove Pt-DNA adducts. AmB and NVB can reverse cisplatin resistance in SKOV3/cp cells.

Adenocarcinoma↗
PubMed1996

[Detection and clinical pathological significance of the expression of P21, P185, p53 proteins and mutation of ras, p53 genes in transitional cell carcinoma of the bladder].

In order to find the significance of gene changes in the development of transitional cell carcinoma of bladder, immunohistochemical and PCR-RFLP methods were used to study the expression of P21, P185, p53 proteins and mutations in ras and p53 genes. The results showed that the P21, P185 and p53 positive rates were 59.3%, 55.3% and 29.3% respectively. Positive rates for P21 and P185 decreased with the progression of the pathological grade (P < 0.05). p53 positive rates decreased with the progression of pathological grade (P < 0.01). Positive expression of P21, P53 were significantly correlated with prognosis. Expression of more than two kinds of oncogene proteins were present in 73 cases of bladder transitional cell carcinoma. The rate of point mutation in codon 12 of Ha-ras gene of bladder transitional cell carcinoma was 32%. The p53 gene mutation rate of bladder transitional cell carcinoma was 18%, all mutations occurred at codon 248. The point mutation in codon 12 of Ha-ras gene increased with the progression of pathological grade (P < 0.05). The ras and p53 gene mutations were significantly correlated with prognosis (P < 0.05). The mortality of patients with ras and p53 gene mutation were higher than patients without mutations. 4 cases of bladder transitional cell carcinoma contained both ras and p53 gene mutations.

Adult↗
PubMed1996

[Increased promoter activity of human delta-globin gene with point mutation of C-T at site-64].

With PCR point mutation technique, the CCAAC box in the promoter region of delta-globin gene was changed into CCAAT which is required in the normal transcription of beta-globin gene at the corresponding site. The normal and mutant segments of the delta-globin promoter region obtained with each segment of about 300 bp (-280/+54 bp), a fragment sufficient for the requirement of its normal promoter function, were separately cloned into pUC19/Hinc II. After sequencing, it showed that the CCAAC box had been successfully changed into CCAAT without other mutations. The two segments were released by Nco I and BamH I, and were cloned into the corresponding site of plasmid pMG3 which has the firefly luciferase as its reporter gene. The positive clones were selected by Dot Blot and were comfirmed with restriction mapping. Then the two recombinant plasmids were transfected into HeLa cell line respectively and the promoter activities of the two fragments were identified by comparing the light intensity generated by the cell extracts when added with luciferase assay substrate. The results demonstrated that the luminescence of the mutant group is on average five times higher than that of the normal group, which indicate that the C-T mutation of the CCAAC box of delta-globin promoter region could increase its promoter activity. Our results have confirmed the hypothesis that the sequence of CCAAC box of human delta-globin gene is one of the main reasons which accounts for its low expression level. The author is now studying the specific DNA binding protein of the upstream promoter region of human delta-globin gene.

Globins↗
PubMed1995

Localization and reactivity of an immunodominant domain in the NS3 region of hepatitis C virus.

Analysis of the amino acid sequences of the nonstructural region 3 (NS3) of the hepatitis C virus type 1 revealed four points with a high average hydrophilicity (Ah). Two of these potential antigenic sites were expressed in E. coli as short fragments. The first fragment of 91 residues (NS3f3: residues 1359-1449) harbors the hexapeptide K-K-K-C-D-E with an Ah of 2.33; the second fragment is 73 residues long (NS3f4: residues 1460-1532) and encompasses the heptapeptide R-S-N-R-R-G-R with an Ah of 1.79. Both fragments were expressed with truncated hepatitis B core (tHBc) as a carrier protein. The fusion proteins were purified from the bacterial lysates by affinity chromatography on immobilized monoclonal antibodies against HBc, and evaluated as antigens in an enzyme immunoassay for the detection of HCV antibodies. In a specificity control panel, reactivity with NS3f3 was only found in proven HCV carriers, while reactivity with NS3f4 was weak in HCV carriers but accounted for some of the nonspecific serological reactions. In a group of 48 genotyped HCV-infected volunteer blood donors, antibodies against NS3f3 were detected in 90% (27/30) of HCV-type 1 infections and in all HCV-type 4 infections (5/5).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1995

Isolation of cDNA encoding a novel serpin of crayfish hemocytes.

We have cloned a serpin-type proteinase inhibitor from a crayfish hemocyte cDNA library. The deduced amino acid sequence consists of 429 amino acids with a putative signal peptide of 21 amino acids. The mature protein has a calculated molecular mass of 45,029 daltons. Identities ranging up to 38% were observed between the crayfish serpin and other members of the serpin family. Phylogenetic analysis shows that the crayfish serpin has a closer relationship to insect serpins than to other animal serpins. Phe369-Ser370 were proposed to be the P1-P1' residues of the inhibitor reactive site. This protein was found to be expressed in hemocytes but not in the hepatopancreas of the crayfish Pacifastacus leniusculus.

Amino Acid Sequence↗
PubMed1995

Detection and identification of mycobacteria by DNA amplification and oligonucleotide-specific capture plate hybridization.

We have developed an easy and rapid detection and identification system for the diagnosis of mycobacterial diseases. The system is based on selective amplification by PCR of mycobacteria with primers based on the genes coding for 16S rRNA. During PCR, a label (digoxigenin-11-dUTP) is incorporated with biotinylated species-specific oligonucleotides (oligonucleotide-specific capture plate hybridization [OSCPH]. One oligonucleotide specific for the genus Mycobacterium and seven species-specific (Mycobacterium tuberculosis, M. avium, M. intracellulare, M. scrofulaceum, M. xenopi, M. genavense, and M. chelonae) oligonucleotides were designed as capturing probes. After specific hybridization, an enzyme immunoassay reveals the specifically bound complexes and thus permits identification of the mycobacterium. A total of 70 mycobacterial strains were tested. For 69 strains, results concordant with conventional identification were obtained. One M. chelonae strain was negative with the M. chelonae probe and was later reidentified as M. fortuitum. Moreover, for 15 clinical samples suspected of harboring nontuberculous mycobacteria, OSCPH was able to confirm all culture results and could identify one M. genavense infection for which standard culture results were negative. PCR-OSCPH is easily applicable and much faster than culture. It could become a valuable alternative approach for the diagnosis of mycobacterial infections.

Base Sequence↗
PubMed1995

[Over expression of alpha-hANP in two kinds of expression systems of Escherichia coli].

Two kinds of expression plasmids carried Ref-Adaptor-(alpha-hANP) hybrid gene have been constructed. The adaptor GAA is the codon of glutamic acid which is a recognition site of the endoproteinase Glu-C. The expression of the heterologous fusion gene was controlled by the bacteriophage lambda PL promoter in the Escherichia coli expression system which is affected by the cIts857 repressor. These overproduced proteins were found in the form of inclusion bodies and constituted 35% and 48% of the total cellular protein respectively. The fusion protein was isolated and cleaved with Glu-C to liberate mature alpha-hANP, which demonstrated significant activities for reduction of blood pressure and vasorelaxation comparable to that of the chemically synthesized hormone. In this paper, the comparison between the two kinds of expression systems is also discussed.

Animals↗
PubMed1995

[Studies on the enzyme cytochemistry of Toxoplasma gondii and the influence of artemether].

Male mice of Kunming strain were infected with 10,000 tachyzoites intraperitoneally. 2 hours after infection the mice were divided into 2 groups and administered 5% of amylum and 200 mg/kg of artemether by gavage for 8 consecutive days. The ultrastructural enzyme cytochemical studies on cytidine monophosphatase (CMP-ase) and glucose-6-phosphatase (G-6-P-ase) of the parasites were carried out. CMP-ase was found scattered in the lysosomes of the parasites as well as in the macrophages. No differences were observed in the localization and intensity of CMP-ase activity between the nontreated and treated with drug parasites. G-6-P-ase was found surrounding the parasite membrane and scattered in the parasitophorous vacuole in the nontreated parasites. After treatment with artemether, the intensity of G-6-P-ase activity was decreased compared with nontreated control parasites. It is suggested that artemether may exert some action on the G-6-P-ase of T. gondii and thus influence the energy metabolis of the parasite.

Animals↗
PubMed1995

[G gamma/A gamma, A gamma I/A gamma T ratios of fetal hemoglobin of Han, Hui, Uygur and Kazak newborns in Xinjiang and gene mapping analysis of two cases with abnormal ratio].

The G gamma/A gamma, A gamma I/A gamma T ratios of fetal hemoglobin of 372 cord blood samples of newborns (Han 102, Hui 102, Uygur 99, and Kazak 69) in Urumchi were determined by HPLC. The means of G gamma ratios of 4 ethnic groups (Han, Hui, Uygur, and Kazak) were 66.83%, 68.33%, 70.44% and 69.70%, respectively. 4 cases (Hui 3 and Kazak 1) with low G gamma (< 50%), and 25 cases (Han 5, Hui 4, Uygur 11 and Kazak 5) with high G gamma (> 80%) were found. The occurrences of low G gamma in Hui and Kazak were 2.94% and 1.45% while in Han and Uygur no single case with low G gamma was found. Those of high G gamma in 4 ethnic groups were 4.9% (Han), 3.9% (Hui), 11.1% (Uygur) and 7.2% (Kazak), respectively. A gamma T heterozygotes in Han 21, Hui 23, Uygur 26 and Kazak 29 cases, and one A gamma T homozygote in each ethnic group were found. The average values of A gamma I were 56.83%, 55.58%, 50.94% and 54.68% respectively. The frequencies of A gamma T gene were 0.113, 0.123, 0.141 and 0.225, respectively. The gene arrangement of a low G gamma case was identified as-GA gamma I-/-G gamma-A gamma I-, and that of a high G gamma case as -G gamma-AG gamma-A gamma I(A gamma T)-/-G gamma-A gamma T(A gamma I)-.

China↗
PubMed1995

[153Sm-EDTMP for moderate and severe bone cancer pain].

One hundred and thirty-six patients with bone cancer pain were treated with 153Sm-EDTMP (ethylenediamine-tetramethylene phosphonic acid). Pain free was noted in 49 cases (36%, 49/136) and pain relief in 77 cases (56.6%, 77/136), the total relief rate being 92.6% (126/136). The data from 76 patients with moderate and severe pain showed there were no significant relationships between the patients' age, the dose of 153Sm-EDTMP and the analgesic effects (P > 0.05). The pain relief observed in the patients with chest pain (ribs metastases) was earlier than that in other groups (P < 0.05). We didn't find any clinical side-effects, so 153Sm-EDTMP is safe for use.

Adult↗
PubMed1995

[Detection of the expression of P21, P53, P185 proteins and the mutation of ras, p53 genes in colorectal adenoma and carcinoma].

Expression of P21, P53, P185 proteins, mutations of ras, p53 genes in colorectal adenoma, carcinoma and transitional mucosa were studied using immunohistochemicstry and PCR-RFLP methods. The results showed that the positive rates of P21, P53 and P185 proteins in colorectal adenoma were 53.3%, 27.6% and 13.3% respectively, the expression of P21 and P53 were associated with the malignant potential of adenoma. The positive rates of P21, P53 and P185 proteins in colorectal carcinoma were 72.9%, 37.8% and 47.2% respectively. 9 adenomas and 40 carcinomas contained more than two protein expressions and their co-expression was associated with the malignant potential of adenoma and the prognosis of carcinoma. The mutation rates of ras gene in colorectal adenoma and carcinoma were 26.7% and 41.9% respectively. The ras gene mutation was associated with the malignant potential of adenoma. The mutation rates of p53 gene (codon 248) in adenoma and carcinoma were 3.3% and 14.9% respectively. The prognosis of patients having gene mutation of both ras and p53 were poor. The results suggested that the alterations of ras, p53 and c-erbB-2 genes are involved in the tumorigenesis and development of colorectal carcinoma.

Adenocarcinoma↗
PubMed1994

Structure and biological activity of a 1,3-beta-D-glucan-binding protein in crustacean blood.

The prophenoloxidase activating system, an enzyme cascade present in arthropod blood, has been shown to be involved in defense and recognition reactions. This system is converted to its active form by fungal 1,3-beta-D-glucans through binding to a plasma protein, a 1,3-beta-D-glucan-binding protein. Here the molecular cloning and carbohydrate composition of the 1,3-beta-D-glucan-binding protein from the freshwater crayfish Pacifastacus leniusculus are reported. It is also demonstrated that this protein can act as an opsonin, stimulating phagocytic uptake of yeast particles by isolated blood cells. The deduced amino acid sequence of 1,339 residues shows no significant similarity to proteins with similar functions in other animals such as the mannan-binding and lipopolysaccharide-binding proteins present in mammals. However, a short sequence motif with similarity to the active site of microbial 1,3-1,4-beta-D-glucan 4-glucanohydrolases was found to occur twice in the 1,3-beta-D-glucan-binding protein.

Amino Acid Sequence↗