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Biomedical subjects

Wei Cao

Publications and source records attributed to Wei Cao.

84 records · Page 5Linked to original sources
PubMed2002

[Extended-spectrum beta-lactamase detection in Enterobacteriaceae and antibiotic susceptibility analysis].

OBJECTIVE: To detect the extended-spectrum beta-lactamases (ESBLs) in family Enterobacteriaceae and analyze the antibiotic susceptibility of those ESBLs-producing strains. METHODS: ESBLs were determined by the double-disk confirmatory test and 8 antibiotic susceptibilities were tested with the disk disffusion method in those strains producing ESBLs. RESULTS: Forty-seven ESBLs-producing strains comprised of 25 of E. coli, 14 of K. pneumoniae, 5 of E. cloacae, 1 of K. oxytoca, 1 of K. rhinoscleromatis, and 1 of S. liquefaciens. The susceptibility rates of those strains were: 100% for imipenem and meropenem, 89.4% for piperacillin/tazobactam, 72.4% for cefoxitin and 65.9% for cefotetan. CONCLUSION: E. coli and K. pneumoniae are the prime strains producing ESBLs in Enterobacteriaceae. Imipenem and meropenem are the best drugs to deal with those ESBLs-producing strains. Piperacillin/tazobactam is better than cephamycins and other beta-lactama/beta-lactamase inhibitor combination.

Anti-Bacterial Agents↗
PubMed2002

Cytoskeleton participation in subcellular trafficking of signal transduction proteins in rod photoreceptor cells.

Light sensitivity and adaptation, general characteristics of rod photoreceptor cell vision, allow rods to modulate their response depending on the lighting environment to which they are exposed. In dim light, rods are maximally sensitive, whereas, in bright light, rods are essentially inactive. In the retinas of dark-adapted mice, arrestin (an inhibitory protein) is located in the rod inner segment (RIS), and transducin (an activating protein) is located in the rod outer segment (ROS). In light-adapted retinas, the proteins have reciprocal localizations. In this study, our data demonstrate that the temporal and spatial changes in the subcellular localization of arrestin and beta-transducin are correlated with the amount of light to which the animals are exposed. By using the frog Xenopus laevis and immunofluorescence confocal microscopy, our results also show that in the dark-adapted retina some arrestin remains in the ROS. The data most dramatically demonstrate that this residual arrestin is highly concentrated in the connecting cilium, the axoneme, and the microtubules associated with the disc incisures. These data suggest a structure-function relationship between the light-dependent positional status of arrestin and the elements of the rod photoreceptor cytoskeleton. The massive, rapid, light-induced reciprocal changes in the subcellular concentrations of these proteins must directly affect phototransduction and appear to be a general phenomenon by which photoreceptor cells rapidly and transiently regulate the trafficking and subcellular concentration of a variety of signal transduction proteins within the RIS and ROS. Hereditary mutations in the components of the movement mechanism should lead to defects in vision and possibly blindness.

Animals↗
PubMed2002

XY99-5038 promotes long-term survival of cultured retinal neurons.

We have previously reported that XY99-5038, a preparation from a specific formula of Traditional Chinese Medicine, could effectively inhibit hydrogen peroxide-induced retinal cell death. In the present study, we investigated the possibility of XY99-5038 to prolong neuronal survival in a long-term retinal neuronal culture. Basic fibroblast survival factor (bFGF), a potent neurotrophic factor, was employed as comparable agent. Retinas of 0-2 days old Sprague-Dawley rats were isolated and dissociated. The cells were maintained in tissue culture for up to 9 weeks in a synthetic serum-free media. XY99-5038 (100 ng/ml) or a vehicle was added to culture every 3-4 days, starting at the first week of culturing. The number of cells were counted and compared for each time point and treatment. Cell viability was also determined by MTT assay, whereas apoptotic cell death was evaluated by the TUNEL assay. XY99-5038 treatment significantly reduced cell loss, increased cell viability, and inhibited apoptosis in this long-term retinal neuronal culture. Our data also show that the protective effect of XY99-5038 is more potent than that of bFGF. Our data suggest that XY99-5038 could be beneficial to the prolongation of neuron survival.

Aging↗
PubMed2002

[Adriamycin thermotherapy through hepatic artery for model of VX2 carcinoma in rabbit liver].

BACKGROUND & OBJECTIVE: It was reported that heating can enhance sensitivity of rabbit VX2 cell to adriamycin and increase intracellular concentration of adriamycin. This study was designed to evaluate the anti-tumor effects of interventional hyperthermia and interventional chemotheramotherapy on VX2 carcinoma in rabbit liver. METHODS: VX2 carcinoma cells were surgically implanted into the right liver lobe of 60 male New Zealand white rabbits, which were randomly divided into 4 groups(15 rabbits per group). To inject physiological saline(37 degrees C), adriamycin (37 degrees C), physiological saline(60 degrees C), and adriamycin (60 degrees C) in different groups via hepatic artery of the rabbits with liver cancer. One week later, to observe the volume of tumor, the serum level of aspartate transaminase(AST), and observe the survival period of VX2 rabbits. RESULTS: In group of ADM(60 degrees C), the tumor growth rate (0.53 +/- 0.21)% was significantly lower than group 2(1.09 +/- 0.26)%, group 3(3.32 +/- 1.28)%, and group 4(3.48 +/- 1.17)% (P < 0.05, P < 0.05, P < 0.01, respectively). The survival period of adriamycin (60 degrees C) group (50.0 +/- 2.0)d was significantly higher than the untreated control group (40.5 +/- 3.0)d, (P < 0.05). The serum level of AST of TNP-470 with lipiodol group was not higher than the other treated groups(P > 0.05), but being significantly higher than the untreated control group after treated(P < 0.05). CONCLUSION: Adriamycin (60 degrees C) greatly decreases the tumour growth rate, and prolongs the survival period.

Animals↗
PubMed2002

[Effect of interventional chemothermotherapy on vascular permeability of tumor liver tissue and normal liver tissue in VX-2 tumor-bearing rabbits].

BACKGROUND & OBJECTIVE: It was reported that heating could enhance the sensitivity of chemotherapy with Adriamycin and increase the intracellular content of Adriamycin. The aim of this study was to investigate the effect of interventional chemothermotherapy on vascular permeability of tumor liver tissue and normal liver tissue in VX-2 tumor-bearing rabbits. METHODS: Thirty rabbits used as implanted hepatocarcinoma model were randomly divided into 3 groups: non-perfusion group (injected only with 1% Evans blue after catheterization), normothermic perfusion group (the perfusion fluid was 25 degrees C normal solution), and hyperthermic perfusion group(the perfusion fluid was 60 degrees C normal solution). The contents of Evans blue in the tissues of three groups, which were used as the indices of vascular permeability, were calculated by the standard curve and spectrophotometry. RESULTS: The Evans blue contents in tumor liver tissue and normal liver tissue is statistically different (P < 0.05). There was no over difference of the Evans blue contents in two kinds of tissue between normal perfusion group and non-perfusion group. There was overt difference of the Evans blue contents in two kinds of tissue between hyperthermic perfusion group and normothermic perfusion group. CONCLUSION: Interventional chemothermotherapy could increase the vascular permeability of normal liver tissue and tumor liver tissue.

Animals↗
PubMed2001

Collagen distribution and expression of matrix metalloproteinases 1 and 13 in patients with anastomotic leakage after large-bowel surgery.

PURPOSE: Despite improved surgical techniques, anastomotic leakage is still a serious complication in colorectal surgery, resulting in increased morbidity and mortality. Based on recent studies showing a disturbance of the collagen synthesis in hernia patients, this pilot study was designed to find out whether there are any hints of disorders concerning the collagen metabolism in patients developing anastomotic leakage after colonic surgery. METHODS: Ten samples of colonic tissue from patients who developed anastomotic dehiscence after surgery for colonic cancer were compared with 14 specimens from patients with uncomplicated anastomotic healing. All samples were obtained at the primary operation. We performed a sirius red test for the overall collagen content and immunhistochemical studies facing differentiation between collagen I and III and the expression of MMP-1 and MMP-13. RESULTS: In the bowel sections from patients developing anastomotic leakage, decreased levels of collagen I and III, and a smaller amount of overall collagen were found. The ratio of collagen I:III was similar in both groups. While MMP-1 was expressed in all samples, there was a difference concerning the expression of MMP-13. In only 6 of 14 patients with uncomplicated healing was MMP-13 present, while in 9 of 10 patients developing a leakage. CONCLUSIONS: Our data may indicate the presence of an individual disturbance of the collagen metabolism in patients developing a leakage after colorectal surgery. Further studies are underway to define more precisely whether a preexisting impairment of wound healing could be a risk factor for anastomotic leakage.

Adult↗
PubMedDate not supplied

Flow injection-chemiluminescence determination of amoxycillin using potassium permanganate and formaldehyde system.

It was found that amoxycillin can react with potassium permanganate in an acidic medium to produce chemiluminescence, which is greatly enhanced by formaldehyde. The optimum conditions for this chemiluminescent reaction were studied in detail using a flow-injection system. The experimental results indicate that, under optimum conditions, the chemiluminescence intensity is linearly related to the concentration of amoxycillin in the range 5.48 x 10(-8)-2.74 x 10(-6) mol/L, with a detection limit (3sigma) of 4.1 x 10(-8) mol/L. The relative standard deviation was 1.0% at 1.1 x 10(-6) mol/L amoxycillin (n = 11 measurements). This method has the advantages of high sensitivity, fast response and ease of operation. The method was successfully applied to the determination of amoxycillin in raw medicines and capsules.

Amoxicillin↗
PubMedDate not supplied

Flow-injection-chemiluminescence method for the determination of penicillin G potassium.

The degradation product of penicillin G potassium can react with potassium permanganate in acidic medium and produce chemiluminescence, which is greatly enhanced by formaldehyde. The optimum conditions for this chemiluminescent reaction were studied in detail using a flow-injection system. The experiments indicated that under optimum conditions, the chemiluminescence intensity was linearly related to the concentration of penicillin G potassium within the range 1.0 x 10(-7)-1.0 x 10(-5) g/mL, with a detection limit (3sigma) of 7 x 10(-8) g/mL. The relative standard deviation was 1.0% for 4.0 x 10(-7) g/mL penicillin G potassium solution (n = 11). This method has the advantages of simple operation, fast response and high sensitivity. The method was successfully applied to the analysis of penicillin G potassium in raw medicines.

Flow Injection Analysis↗
PubMedDate not supplied

Reduced expression of collagen type I and increased expression of matrix metalloproteinases 1 in patients with Crohn's disease.

Crohn's disease (CD) is a chronic inflammatory bowel disease of still unknown etiology. The aim of our study was to find out whether there are any changes in the colonic wall of CD patients that could give hints for a predisposing disorder concerning the extracellular matrix, especially the collagen metabolism. Eight samples of colonic tissue from patients with Crohn's disease were compared to 14 specimens from patients without Crohn's disease. We performed a sirius red test for the overall collagen content and immunohistochemical studies examining differentiation between" collagen type I and type III and the expression of MMP-1 and MMP-13. In the bowel sections of patients with Crohn's disease, decreased levels of mature collagen type I with a resulting lower ratio of collagen I/III compared to patients without Crohn's disease were found (1.12 +/- 0.29 vs. 1.59 i 0.31). The expression of MMP-1 was significantly increased in the CD group (9.21 i 6.02 vs.6.02 i 1.98), whereas expression of MMP-13 showed no difference in both groups. Our study gives the first indication that preexisting changes of the extracellular matrix in the colonic wall may play a role in the pathogenesis of CD. Further studies have to be done to elucidate these interesting aspect of the pathogenesis in Crohn's disease.

Collagen Type I↗
PubMedDate not supplied

Pharmacology and toxicology of a new aqueous formulation of intravenous amiodarone (Amio-Aqueous) compared with Cordarone IV.

Hypotension is the most frequent adverse event reported with intravenous amiodarone (Cordarone IV). The hypotension has been attributed to the vasoactive solvents of the formulation, polysorbate 80 and benzyl alcohol, both known to exhibit negative inotropy and hypotensive effect. A new aqueous formulation of intravenous amiodarone (Amio-Aqueous) does not contain vasoactive excipients and may be less toxic and cause less hypotension than Cordarone IV. This hypothesis was tested in a series of animal studies with direct comparison of Amio-Aqueous and Cordarone IV. All studies were performed on Sprague-Dawley rats. The acute toxicology study showed that both LD50 and LD100 were 30% greater for Amio-Aqueous than for Cordarone. At the dose at which all animals expired on Cordarone, 50% of animals were still alive on Amio-Aqueous. The study on myocardial contractility showed that Amio-Aqueous was a far less negative inotropic than Cordarone IV (P < 0.001). Amio Aqueous did not have an effect on contractility at 5- and 10-mg/kg dose levels while Cordarone resulted in a 25% (P < 0.01) and 29% (P < 0.002) decrease, respectively. The study on arterial blood pressure showed that Cordarone caused a significant decrease in blood pressure at each of the 3, 5, 10, and 20 mg/kg doses (P < 0.05 to P < 0.001) while Amio-Aqueous did not. The study on the antiarrhythmic effects showed comparable efficacy for both formulations. In conclusion, Cordarone IV was more toxic and caused significant hypotension and negative inotropy while Amio-Aqueous lacked the hypotensive and cardiotoxic properties of Cordarone. Therefore, Amio-Aqueous is a safer alternative than the standard formulation.

Amiodarone↗
PubMedDate not supplied

The effect of magnesium sulfate on action potential duration and cardiac arrhythmias.

To evaluate the electrophysiologic and antiarrhythmic effects, Mg was infused at 15 mg/h (n = 5) or an equal volume of saline (1.2 mL/h) (n = 5) and electrocardiogram and action potential duration (APD) recorded every 15 minutes. Rats were anesthetized with 70 mg/kg pentobarbital intraperitoneally. Mg increased QT 15 +/- 6% on average compared with 1 +/- 4 for saline P < 0.01. Mg increased QT, 0, 0, 6 +/- 4, 13 +/- 5, 16 +/- 4, 23 +/- 5, 29 +/- 8, and 32 +/- 5% over baseline after a 2 hours infusion (P < 0.01). APD increased by 0, 6 +/- 3, 8 +/- 8, 14 +/- 4, 16 +/- 12, 21 +/- 4, 25 +/- 5% change from baseline (P < 0.05). The mean percentage of increase was 12 +/- 8 for the Mg group and 1 +/- 3 for the saline group (P < 0.05). The JT interval also increased after Mg (P < 0.01). After Mg loading, coronary occlusion of the left anterior descending coronary artery was performed. Ventricular premature contractions (VPCs), ventricular tachycardia (VT), and ventricular fibrillation (VF) were frequent in the saline control group, with 2 dying in VF; with only scattered VPCs and short runs of nonsustained VT in the Mg group. The results of these findings indicate that infusion of MgSO4 can prolong the QRS, QT, and JT intervals in the rat and these changes correlate well with arrhythmia suppression.

Action Potentials↗