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Biomedical subjects

W Guan

Publications and source records attributed to W Guan.

At least 37 records · Page 2Linked to original sources
PubMed1999

Preparation of GFLV CP-gene cDNA probe labeled by photosensitive biotin and its application in detection of GFLV.

The cDNA of the GFLV CP gene amplified from clone pGAB5 by PCR was labeled by photosensitive biotin. The probe sensitivity is 5 pg, and the detectable amount of unlabeled GFLV cDNA was 10 pg by Dot-blot hybridization when the biotin-labeled cDNA was used as a probe. The results of detection for GFLV by probe have positive correlation with those of ELISA. The minimum amount of grapevine tissue for detection by probe was 100 times lower than that by ELISA. The seasons and the position of grapevine leaves do not limit application of this method.

Biotinylation↗
PubMed1999

[Clinical significance and expression of Bcl-2 protein in patients with systemic lupus erythematosus].

OBJECTIVE: To investigate the pathogenesis and clinical evaluation for expression of Bcl-2 in lymphocytes and renal tissues of 31 patients with systemic lupus erythematosus (SLE). METHODS: Bcl-2 protein levels in T, B cells and renal tissues were examined by two-colour cytofluorography, and immunohistochemical staining (LSAB method) respectively. RESULTS: Compared with inactive SLE patients and normal controls, a proposition of T cells (including CD(3)(+), CD(4)(+) and CD(8)(+) subgroups) expressing Bcl-2 protein increased significantly in active SLE patients. However, Bcl-2 protein levels are not statistically different in CD(19)(+) B cells among all groups. Mean fluorescence intensity (MFI) levels of Bcl-2 protein on CD(3)(+) T cells was positively related to SLE disease activity index (SLEDAI) among the SLE patients, which wasn't related to ESR, complement (C(3), C(4)) and autoantibody (ANA, anti-dsDNA, anti-Sm) positivity. The population of Bcl-2 positive intraglomerular cells was correlated significantly with the grade of mesangial cell increase and the number of proliferating cell nuclear antigen (PCNA) positive glomerular cells, and 24-hour urinary protein. CONCLUSION: Overexpression of apoptosis-related Bcl-2 protein might play an important rule in the prolonged proliferation of mesangial cells and glomerular hypercellularity and in the active period of SLE patients, Bcl-2 expression levels of peripheral blood T lymphocytes might serve as an active index for SLE.

Adult↗
PubMed1999

[Expression and stability of fragment of Plasmodium merozoite major surface protein 1 in recombinant attenuated Salmonella typhimurium].

OBJECTIVE: To determine the invasive ability of recombinant attenuated Salmonella typhimurium X4064 (pQEM1) strain containing gene fragment of Plasmodium falciparium merozoite surface protein 1 (MSP1), the stability of its plasmid, and its re-expression. METHODS: BALB/c mice were fed with recombinant attenuated S. typhimurium containing No. 1 gene fragment of P. falciparium MSP1 by gastric tube. Plate incubation, plasmid endonuclease analysis and Western blot were used to identify the recombinant attenuated S. typhimurium strains isolated from mice and the ability of re-expression, and its growth were determined in vitro. RESULTS: The attenuated strain X4064 of S. typhimurium isolated from mice contained recombinant plasmid pQEM1, no. 1 MSP1 fragment of P. falciparium was expressed in vitro in S. typhimurium X4064 (pQEM1) strain, and its growth curve of X4064 (pQEM1) strain in mice was basically similar to that of X4064. CONCLUSION: The recombinant plasmid pQEM1 could steadily exist in the X4064 strain of S. typhimurium, without influence on its invasion into host cells. X4060 (pQEM1) strain isolated from infected mice still had the ability to re-express M1 protein.

Animals↗
PubMed1999

[Quantification of female teenagers' competence of sexual cognition].

Compiling a questionnaire of sexual cognition for surveying 224 female teenagers (11 to 14 years old), the results showed that they were deficient in the knowledge of sexual physiology, mortality and law. And also, the deficiency had a high co-relationship with the age of surveyed female teenagers. It suggested that this questionnaire be valuable in the quantification of sexual cognition.

Adolescent↗
PubMed1998

A novel mechanism-based mammalian cell assay for the identification of SH2-domain-specific protein-protein inhibitors.

BACKGROUND: Many intracellular signal-transduction pathways are regulated by specific protein-protein interactions. These interactions are mediated by structural domains within signaling proteins that modulate a protein's cellular location, stability or activity. For example, Src-homology 2 (SH2) domains mediate protein-protein interactions through short contiguous amino acid motifs containing phosphotyrosine. As SH2 domains have been recognized as key regulatory molecules in a variety of cellular processes, they have become attractive drug targets. RESULTS: We have developed a novel mechanism-based cellular assay to monitor specific SH2-domain-dependent protein-protein interactions. The assay is based on a two-hybrid system adapted to function in mammalian cells where the SH2 domain ligand is phosphorylated, and binding to a specific SH2 domain can be induced and easily monitored. As examples, we have generated a series of mammalian cell lines that can be used to monitor SH2-domain-dependent activity of the signaling proteins ZAP-70 and Src. We are utilizing these cell lines to screen for immunosuppressive and anti-osteoclastic compounds, respectively, and demonstrate here the utility of this system for the identification of small-molecule, cell-permeant SH2 domain inhibitors. CONCLUSIONS: A mechanism-based mammalian cell assay has been developed to identify inhibitors of SH2-domain-dependent protein-protein interactions. Mechanism-based assays similar to that described here might have general use as screens for cell-permeant, nontoxic inhibitors of protein-protein interactions.

Animals↗
PubMed1998

[The inhibitory effect in vitro of salvia miltiorrhiza and tetramethyl pyrazine on the growth of fibroblasts].

In order to investigate the inhibitory effect of salvia miltiorrhiza (SM) and tetramethyl pyrazine (TP) on scartricial fibroblast, the hypertrophic scar tissue of chest was chosen for culture of fibroblasts, and the influence of SM and TP on fibroblasts was observed, The effect of the drugs on the growth of fibroblasts, on DNA synthesis of fibroblasts and on mitosis index of fibroblasts were all determined quantitatively. The results showed: 1. SM and TP could inhibit significantly the growth of the fibroblasts, the inhibitory effect was irreversible when the concentration of the drugs reached 5 mg/ml and 500 micrograms/ml respectively; 2. SM and TP could inhibit the absorption of 3H-TdR and this effect was correlated positively to the dosage of the drugs and; 3. SM and TP could reduce the mitosis index of fibroblasts. It was concluded that SM and TP had definite depressive effect on growth of fibroblasts which was correlated positively with the concentration of drugs and duration of application. The inhibitory effect of the drugs on fibroblasts was mainly through inhibition of synthesis of DNA.

Burns↗
PubMed1998

[The influence of salvia miltiorrhiza and tetramethyl pyrazine on DNA content of cicatricial fibroblasts and its cellular cycle].

In order to study the mechanism of the inhibitory effect of salvia miltiorrhiza (SM) and tetramethyl pyrazine (TP) on scar fibroblast, the DNA content of fibroblast and the all distribution in cellular cycle was measured by FCM. The hypertrophic scar tissue of chest was chosen for primary culture of fibroblast. Then this cultured cell was reacted with SM and TP. FCM was used to measure the DNA index and duration of cellular cycle. The results showed that: 1. SM and TP had little effect on DNA index, but when the concentration of drugs reached the threshold, they could increase the amount of fibroblasts in C2-M stage and the duration of G2-M stage was prolonged; 2. TP could also prolong the duration of S-stage; 3. SM and TP could prolong the multiplication time of fibroblasts and this effect was correlated postively with the dosage of drug. The conclusions were that the inhibitory effect of SM was the result of inhibiting the mitosis of cells and the cellular cycle be at a standstill in G2-M stage. The inhibitory effect of TP was due to the inhibition of synthesis and duplication of DNA and cellular mitosis, and the cellular cycle was also at a standstill in G2-M stage.

Burns↗
PubMed1998

[Living related liver transplantation: a case report].

OBJECTIVE: To study a case of living related liver transplantation. METHOD: The patient was a 10-year-old girl who suffered from congenital diffuse intrahepatic cholangiectasis, recurrent cholangitis and hepatocirrhosis. The donor was the patient's father aged 40. The left lateral lobe of donor's liver was cut and grafted to the patient. Intensive care and treatment as well as follow-up were given after operation. RESULT: For the donor, the operation lasted 400 min, with 410 ml bleeding and 300 g liver removed. The recovery was satisfactory. For the recipient, the operation lasted 652 min, with 1665 ml bleeding, 80 min non-liver stage, 0 min graft hot ischemic stage, and 137 min cold ischemic stage. Immunosuppressive therapy was given using cyclosporin A, azathioprine and adrenocortical hormones. There was an acute rejection 11 days after operation, which was controlled using hormone impulsive therapy. The patient has been surviving 7 months with normal liver function. CONCLUSION: The living related liver transplantation is feasible under modern surgical conditions. It is demonstrated that perfect postoperative management is the key for the successful liver transplantation.

Adult↗
PubMed1997

[Legal bases for evaluation of mental injuries].

In this article, we study the legislation bases for evaluation of mental injuries, the legislation form of the evaluation standard, and also discuss the degrees of mental injuries.

Combat Disorders↗
PubMed1997

[Improvement of the assay for pre-S2 Ag/Ab detection and its application in different patients].

A new ELISA inhibition test for measuring serum Pre-S2Ab was developed to avoid the "double positive" phenomenon. One hundred and twenty samples with Pre-S2Ab negative were detected for Pre-S2Ab, the critical range for Pre-S2Ab in normal population was confirmed: a positive result was decided while the inhibition ration was over 50%, a negative result was decided while the inhibition ratio was less than 34%, and a dubious result was decided while the ratio was over 34% but less then 50%. At the same time, serum samples from sixty patients with chronic hepatitis B were detected for Pre-S2Ag and Pre-S2Ab, it showed that (1) the positive ratio of HBV DNA in patients with Pre-S2Ag positive was much higher than in patients with Pre-S2Ag negative (P < 0.01); (2) to the 46 patients with HBV DNA positive, Pre-S2Ag had a better relationship with HBV DNA than the HBeAg/Ab did (P < 0.01). Furthermore, to patients with acute hepatitis B, the presence of Pre-S2Ab was closely related to the prognosis of the disease, and the Pre-S2Ab assay could also be used to evaluate the preventive effect of HB vaccine containing Pre-S2Ag.

Enzyme-Linked Immunosorbent Assay↗
PubMed1997

[Effect of biological electric stimulation on free muscle transfer].

The rectus femoris muscles of rabbits were used as muscle model. The electrical stimulation which resembled the normal motor-unit activity was used to observe its effects on free transferred muscle. After three months, the moist muscle weight (MW), its maximum cross-section area, its contractility and its histochemical characteristics were examined. The results showed that the function and morphology of the muscles were well preserved. These findings might encourage its clinical application.

Animals↗
PubMed1995

Agonists and antagonists differentially regulate the high affinity state of the D2L receptor in human embryonic kidney 293 cells.

Studies with radiolabeled antagonists have revealed that both agonists and antagonists induce up-regulation of D2 dopamine receptors in cells transfected to express D2L or D2S receptors. The regulation induced by agonists, but not antagonists, was synergistic with cAMP analogues, and differences in the time courses of the effects of agonists and antagonists have been observed. These findings have been extended by using a radiolabeled agonist to investigate agonist- and antagonist-induced regulation of the high affinity state of the D2L dopamine receptor in transfected HEK 293 cells. Exposure to agonists decreased the proportion of receptors in the high affinity, agonist-preferring state. Exposure to antagonists, however, led to an increase in the density of receptors with a high affinity for agonists. The effects of both agonists and antagonists on the agonist-preferring receptors occurred without a lag and were time and dose dependent. Inhibition of forskolin-stimulated cAMP accumulation by agonists was not affected by exposure of the cells to the antagonist (-)-sulpiride. Desensitization was seen after exposing cells to the agonist quinpirole for 1.5 hr, suggesting that the rapid loss of high affinity binding sites represents an uncoupling of the receptor from the G protein that mediates inhibition of adenylyl cyclase. Pretreatment of cells with the protein synthesis inhibitor cycloheximide did not block the quinpirole-induced loss of receptors with a high affinity for agonists. The effect of (-)-sulpiride on high affinity binding sites was blocked by cycloheximide, but only after incubation of cells for sufficient time to induce an increase in the total number of receptors. After incubation of cells with (-)-sulpiride for a short time, the increase in the number of receptors with a high affinity for agonists was unaffected by cycloheximide. These results suggest that the increase in agonist binding after brief exposure to an antagonist is due to interactions of the receptor with one or more G proteins that are not coupled to inhibition of adenylyl cyclase, whereas the increase in agonist binding at later time points is associated with the antagonist-induced up-regulation.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1995

[Effects of cadmium on calcium homeostasis of isolated epithelial cells of proximal renal tubules].

Changes of intracellular calcium homeostasis in epithelial cell damage of renal tubules caused by cadmium and its relationship with the damage were studied in isolated tubular cells of rabbits. Results showed levels of free calcium (Ca++) in tubular cytoplasm increased significantly with the treatment of cadmium, and a series of cellular ultrastructure were damaged. A calcium channel blocker, phenothiazine, showed blocking and protecting effects on it. This suggested calcium overload played a very important role in kidney damage caused by cadmium.

Animals↗