Biomedical subjects

Gang Cheng

Publications and source records attributed to Gang Cheng.

At least 37 records · Page 2Linked to original sources

PubMed2006

[Removing breast foreign body resulted from augmentation with polyacrylamide hydrogel injection and silicone prosthesis implantation at one stage].

OBJECTIVE: This study was to investigate an operation, in which removing breast cysts of foreign body resulted from augmentation with polyacrylamide hydrogel injection was performed simultaneously with silicone prosthesis implantation under SEPS endoscope in order to relieve tissue injury and increase the accuracy of clearance. METHODS: Eight patients were included in this study. Preoperative type B ultrasound examination was performed to mark the mass. Through an axillary approach, the cysts of foreign body that were distributed in the subcutaneous tissue, breast or muscle were separated and ablated under SEPS endoscope. After removal of the foreign body, a silicone implant was located submuscularly for breast augmentation. RESULTS: The operations were completed without hematoma and infection. Follow-up of the eight patients for 3 to 12 months showed that preoperative symptoms relating to the injected material, such as breast pain, lump and asymmetry, have no longer existed. The shapes of the breasts were satisfactory. CONCLUSIONS: We believe that endoscope-assisted mammoplasty offers more satisfactory clinical results with less injury, less morbidity, less scars, more accuracy and greater patient acceptance.

Acrylic Resins↗

PubMed2006

[Studies on spermatogonial stem cells cultured in vitro of Wuzhishan Mini Porcine].

The isolation and culturation of SSCs of different stage of Wuzhishan Mini Porcine (WZSP) with different way of enzymatic digestion and culturation were deaded in this study. The results of the experiment described are as the following: The proper time of isolation and culturation of SSCs of WZSP is 1-20 old days. Different old of piglets with different method. Using DMEM medium as a fundmental culture medium add different gradient at 34 degrees C in a water-saturated atmosphere of 95% air, 5% CO2. The mulberry-shaped SSCs clusters appeared as original generation in 7-8 days culture. The SSCs clusters developed half-suspendedly in the culture medium. SSCs alkaline phosphatase (AKP) staining expressed positively. Mouse embryonic fibroblast was used as feeder layer for the SSCs passage cultured, The SSCs show good attached attributes, but the number of SSCs decreased quickly after 4 days culture. By seminiferous cord fragment culturation can also appear SSCs clusters in 5 days, The SSCs clusters developed half-suspendedly in the culture medium. In addition, the testes placed in cold (4 degrees C) PBS banlanced salt solution for 24 h also can be used as a good matierials for preparation of SSCs. These results indicate that the method of solation and culturation of SSCs are very correct and efficient, all these can be utilized as a good reference for future studies.

Animals↗

PubMed2005

Colon-specific drug delivery systems based on cyclodextrin prodrugs: in vivo evaluation of 5-aminosalicylic acid from its cyclodextrin conjugates.

AIM: To investigate the release of cyclodextrin-5-aminosalicylic acid (CyD-5-ASA) in cecum and colon. METHODS: An anti-inflammatory drug 5-ASA was conjugated onto the hydroxyl groups of alpha-, beta- and gamma-cyclodextrins (CyDs) through an ester linkage, and the in vivo drug release behavior of these prodrugs in rat's gastrointestinal tract after the oral administration was investigated. RESULTS: The 5-ASA concentration in the rat's stomach and small intestine after the oral administration of CyD-5-ASA conjugate was much lower than that after the oral administration of 5-ASA alone. The lower concentration was attributable to the passage of the conjugate through the stomach and small intestine without significant degradation or absorption, followed by the degradation of the conjugate site-specific in the cecum and colon. The oral administration of CyD-5-ASA resulted in lower plasma and urine concentration of 5-ASA than that of 5-ASA alone. CONCLUSION: CyD-5-ASA conjugates may be used as prodrugs for colon-specific drug delivery system.

Animals↗

PubMed2005

Cell population dynamics modulate the rates of tissue growth processes.

The development and testing of a discrete model describing the dynamic process of tissue growth in three-dimensional scaffolds is presented. The model considers populations of cells that execute persistent random walks on the computational grid, collide, and proliferate until they reach confluence. To isolate the effect of population dynamics on tissue growth, the model assumes that nutrient and growth factor concentrations remain constant in space and time. Simulations start either by distributing the seed cells uniformly and randomly throughout the scaffold, or from an initial condition designed to simulate the migration and cell proliferation phase of wound healing. Simulations with uniform seeding show that cell migration enhances tissue growth by counterbalancing the adverse effects of contact inhibition. This beneficial effect, however, diminishes and disappears completely for large migration speeds. By contrast, simulations with the "wound" seeding mode show a continual enhancement of tissue regeneration rates with increasing cell migration speeds. We conclude that cell locomotory parameters and the spatial distribution of seed cells can have profound effects on the dynamics of the process and, consequently, on the pattern and rates of tissue growth. These results can guide the design of experiments for testing the effectiveness of biomimetic modifications for stimulating tissue growth.

Algorithms↗

PubMed2005

Beta-2 adrenergic receptor gene (ADRB2) polymorphism and risk for lung adenocarcinoma: a case-control study in a Chinese population.

The incidence of lung adenocarcinoma (AC) has been increasing over recent decades. The tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is one of the most potent carcinogens and reproducibly induces a high incidence of lung AC in laboratory animals. In addition to its genotoxic effects, NNK has also epigenetic effects on lung cells by functioning as an agonist for beta adrenergic receptors and stimulating the signal pathways that lead to lung AC. Beta-2 adrenergic receptor (ADRB2) expressed on bronchial smooth muscle is a well-defined target for asthma treatment that has epidemiological implications in lung cancer development. And biochemical effect and pharmacogenetic relevance of regulatory and coding variants of ADRB2 have been well documented. Aiming to test whether the genetic variants of ADRB2 modify risk of lung AC, we compared the manifestation of three common single nucleotide polymorphisms (SNPs) of ADRB2 (G-1023A, G-654A, and A46G (Gly16Arg)) between 313 patients with lung AC and 321 controls. Overall association was not observed between risk and either individual of the three SNPs or their combined haplotypes. However, in the subgroup of young subjects < or =50 years old, significant association was observed for G-1023A (allele based OR, 1.82; 95% CI, 1.12-2.95), A46G (Gly16Arg) (allele based OR, 0.64; 95% CI, 0.40-1.03), and the haplotype A(-1023)A(46) (OR 2.62; 95% CI 1.30-5.27). Our results do not support a major independent role of ADRB2 polymorphisms in lung AC risk, suggesting that functional variants of other genes involved in the NNK epigenetic pathway of carcinogenesis should be investigated.

Asian People↗

PubMed2005

Cross dipole stacking in the crystal of distyrylbenzene derivative: the approach toward high solid-state luminescence efficiency.

Through adding two substituent phenyl groups on distyrylbenzene, we have obtained the cross stacking of 2,5-diphenyl-1,4-distyrylbenzene with two trans double bonds (trans-DPDSB) in crystalline state. In such a cross-stacking mode, the solid-state emission exhibits high-intensity, having characteristics similar to its single molecule. The organic light-emiiting diodes (OLEDs) with attractive performance have been achieved using trans-DPDSB as a light-emitting layer, and the amplified spontaneous emission of the needlelike crystals has been observed.

Benzene Derivatives↗

PubMed2005

CYP2J2*7 single nucleotide polymorphism in a Chinese population.

BACKGROUND: Human cytochrome P450 2J2 (CYP2J2) is the major arachidonic acid epoxygenase that plays important roles in the pathogenesis of a variety of diseases such as cardiovascular disorders and cancers, this P450 also plays a role in the metabolism of some antihistamine drugs. Variability of CYP2J2 gene is highly constrained except for at its proximal promoter a relatively common and functionally relevant single nucleotide polymorphism, namely CYP2J2*7, with allele frequency being 17%, 5.49%, 13%, and 4.23% in African, White, Asian, and Korean, respectively. Since this genetic variation differs strikingly between ethnic groups, we characterized the CYP2J2*7polymorphism in Chinese. METHODS: Polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) assays were used to genotype CYP2J2*7 in a sample of 384 healthy Chinese Han subjects. RESULTS: In this Chinese population, 20 (5.21%) heterozygotes and no homozygote for CYP2J2*7 allele were observed, and the allelic frequency was 2.60%. CONCLUSION: The CYP2J2*7 variant represents a relatively rare polymorphism in Chinese, with the allele frequency being comparable to that of Korean, but significantly lower than those of African and White groups. This data may be informative to design population-based association study of genetic predisposition to CYP2J2 related diseases and treatments.

Alleles↗

PubMed2005

Development of the human superior colliculus and the retinocollicular projection.

We have used carbocyanine dye tracing from the brachium of the superior colliculus in conjunction with Nissl staining and immunohistochemistry to GAP-43 and calretinin to study the development of retinal projections to the superior colliculus in 17 human embryos and fetuses aged from 8 to 28 weeks. Lamination of the superior colliculus begins to emerge by 11 weeks, and by 16 weeks all seven layers of the mature superior colliculus are visible. Fibres immunoreactive to GAP-43 were seen at 13 weeks in the most superficial layers. By 19 weeks, GAP-43 immunoreactivity was present in the stratum opticum as well as the deeper fibres layers, indicating the development of fibre pathways following those laminae. Carbocyanine dye tracing of retinocollicular projections showed extensive rostrocaudally running unbranched fibres in the superficial superior colliculus at 12 weeks. Shortly after this (13 weeks), retinocollicular fibres penetrate the deeper collicular layers and branching becomes apparent. We also saw occasional retrogradely labelled somata following DiI insertion into the superior brachium. Our findings indicate that development of the human superior colliculus and its connections is largely complete by 20 weeks. This would suggest that functional capacity of the human superior colliculus should also be mature by the middle of gestation.

Calbindin 2↗

PubMed2005

Validation of an HPLC method for the determination of scutellarin in rat plasma and its pharmacokinetics.

A validated HPLC method was developed for the quantification of scutellarin in rat plasma using a liquid-liquid extraction and an ultraviolet detection. Chromatographic separation of scutellarin in plasma was performed on a C18 column, with a mobile phase of acetonitrile-water (23:77, v/v), adjusted to pH 2.5 with 1M phosphoric acid, and rutin was used as an internal standard. The calibration curve was linear over the range 0.1-100 microg/ml in rat plasma. The average extraction recoveries were 85.9+/-8.9, 71.0+/-4.6, 72.7+/-1.2% (n=3) at concentrations of 0.1, 2, 100 microg/ml, respectively, and the within-day and between-day precisions were less than 15%. After intravenous administration to rats over the doses range of 10-40 mg/kg, the plasma concentration-time curve of scutellarin was best conformed to three-compartment open model. The AUC of scutellarin was proportional to dose, and the systemic clearance (Cl), elimination half-life (t1/2beta) and apparent volume of distribution (Vc) were not significantly different among the three doses, suggestive of the linear pharmacokinetics characteristic of scutellarin after intravenous administration.

Animals↗

PubMed2005

Short-term administration of (-)-epigallocatechin gallate reduces hepatic steatosis and protects against warm hepatic ischemia/reperfusion injury in steatotic mice.

Hepatic steatosis increases the extent of cellular injury incurred during ischemia/reperfusion (I/R) injury. (-)-Epigallocatechin gallate (EGCG), the major flavonoid component of green tea (camellia sinensis) is a potent antioxidant that inhibits fatty acid synthase (FAS) in vitro. We investigated the effects of EGCG on hepatic steatosis and markers of cellular damage at baseline and after I/R injury in ob/ob mice. Animals were pretreated with 85 mg/kg EGCG via intraperitoneal (ip) injection for 2 days or oral consumption in the drinking water for 5 days before 15 minutes of warm ischemia and 24 hours of reperfusion. After EGCG administration, total baseline hepatic fat content decreased from baseline. Palmitic acid and linoleic acid levels also were reduced substantially in all ECGC-treated animals before I/R. Alanine aminotransferase (ALT) levels decreased in all EGCG-treated animals compared with control animals after I/R. Histologic analysis demonstrated an average decrease of 65% necrosis after EGCG administration. EGCG administration also increased resting hepatic energy stores as determined by an increase in cellular adenosine triphosphate (ATP) with a concomitant decrease in uncoupling protein 2 (UCP2) before I/R. Finally, there was an increased level of glutathione (GSH) in the EGCG-treated mice compared with the vehicle-treated mice both at baseline and after I/R. In conclusion, taken together, this study demonstrates that treatment with ECGC by either oral or ip administration, significantly protects the liver after I/R, possibly by reducing hepatic fat content, increasing hepatic energy status, and functioning as an antioxidant.

Animals↗

PubMed2005

Synthesis and properties of polysaccharide prodrugs of 5-aminosalicylic acid as potential colon-specific delivery systems.

The drug release of the polymer prodrugs of 5-aminosalicylic acid (5-ASA) was not only dependent on the property of the polymers but also dependent on the solubility of the prodrugs. We prepared several polysaccharide prodrugs of 5-ASA to examine the effect of solubility of prodrugs on the release characteristics of 5-ASA in the gastrointestinal contents of rats. The amide prodrug, chitosan-5-ASA (ChT-5-ASA), did not release the 5-ASA in the cecal and colonic contents. The ester prodrugs, hydroxypropyl cellulose-5-ASA (HPC-5-ASA), being poor solubility in 0.05mol/l acetic acid solution also did not release the 5-ASA in any of gastrointestinal contents of rats. Whereas the 5-ASA release from cyclodextrins-5-ASA (CyDs-5-ASA) in cecal and colonic contents was significantly higher than that in stomach and small intestine contents. And furthermore, with the decrease in the degree of substitution, the solubility of CyD-5-ASA increased, and the release of 5-ASA in the gastrointestinal contents was also higher at the same time interval of incubation. When the ratio of cyclodextrin (CyD) and 5-formylaminosalicylic acid (5-fASA), a precursor of 5-ASA prodrugs, was 1:10, CyD-5-ASA was very slightly soluble, and no release of 5-ASA was observed within 48h in gastrointestinal contents. The present results suggested that the ester prodrugs of 5-ASA with certain solubility could release 5-ASA in the cecal and colonic contents of rat.

Animals↗

PubMed2005

The impact of China's retail drug price control policy on hospital expenditures: a case study in two Shandong hospitals.

In China, 44.4% of total health expenditures in 2001 were for pharmaceuticals. Containment of pharmaceutical expenditures is a top priority for policy intervention. Control of drug retail prices was adopted by the Chinese government for this purpose. This study aims to examine the impact of this policy on the containment of hospital drug expenditures, and to analyze contributing factors. This is a retrospective pre/post-reform case study in two public hospitals. Financial records were reviewed to analyze changes in drug expenditures for all patients. A tracer condition, cerebral infarction, was selected for in-depth examination of changes in prices, utilization, expenditures and rationality of drugs. In the two hospitals, a total of 104 and 109 cerebral infarction cases, hospitalized respectively before and after the reform, were selected. Prescribed daily dose (PDD) was used for measuring drug utilization, and the contribution of price and utilization to changes in drug expenditures were decomposed. Rationality of drug use post-reform was reviewed based on published literature. Drug expenditures for all patients still increased rapidly in the two hospitals after implementation of the pricing policy. In the provincial hospital, drug expenditures per patient for cerebral infarction cases declined, but not significantly. This was mainly attributable to reduced utilization. In the municipal hospital, drug expenditure per patient increased by 50.1% after the reform, mainly due to greater drug utilization. Three to five fold higher drug expenditure per inpatient day in the provincial hospital was due to use of more expensive drugs. Of the top 15 drugs for treating cerebral infarction cases after the reform, 19.5% and 46.5% of the expenditures, in the provincial and municipal hospitals, respectively, were spent on drugs with prices set by the government. A large proportion of expenditures for the top 15 drugs, at least 65% and 41% in the provincial and municipal hospitals, respectively, was spent on allopathic drugs without an adequate evidence base of safety and efficacy supporting use for cerebral infarction. Control of retail prices, implemented in isolation, was not effective in containing hospital drug expenditures in these two Chinese hospitals. Utilization, more than price, determined drug expenditures. Improvement of rational use of drugs and correcting the present incentive structure for hospitals and drug prescribers may be important additional strategies for achieving containment of drug expenditures.

China↗

PubMed2005

C16, a novel advanced glycation endproduct breaker, restores cardiovascular dysfunction in experimental diabetic rats.

AIM: Advanced glycation endproducts (AGE) have been implicated in the pathogenesis of diabetic complications, including diabetic cardiovascular dysfunction. 3-[2-(4-Bromo-phenyl)-1-methyl-2-oxo-ethyl]-4,5,6,7-tetrahydro-benzothiazol-3-ium bromide (C16), a novel AGE breaker, was investigated for its effects on the development of cardiovascular disease in diabetic rats. METHODS: Rats that had streptozotocin-induced diabetes for 12 weeks were divided into groups receiving C16 or vehicle by gavage. RESULTS: In hemodynamic studies of the left ventricle, C16 treatment (25 or 50 mg/kg) for 4 weeks resulted in a significant increase in left ventricular systolic pressure, +dp/dt(max), and -dp/dt(max) as compared with vehicle-treated diabetic rats. Furthermore, in hemodynamic studies of the cardiovascular system, C16 (12.5, 25, or 50 mg/kg) treatment for 4 weeks resulted in a dose-dependent and significant increase in cardiac output, a reduction of total peripheral resistance, and an increase in systemic arterial compliance when compared with vehicle-treated diabetic rats. Biochemical studies showed that C16 treatment also resulted in a significant decrease in immunoglobulin G-red blood cell surface crosslink content and an increase in collagen solubility. Morphological and immunohistochemical examinations indicated that C16 was able to prevent increases of the collagen type III/I ratio in the aorta and decrease the accumulation of AGE in the aorta. CONCLUSION: C16 has the ability to reduce AGE accumulation in tissues in vivo, and can restore diabetes-associated cardiovascular disorders in rats. This provides a potential therapeutic approach for cardiovascular disease associated with diabetes and aging in humans.

Animals↗

PubMed2005

Allophanate hydrolase, not urease, functions in bacterial cyanuric acid metabolism.

Growth substrates containing an s-triazine ring are typically metabolized by bacteria to liberate 3 mol of ammonia via the intermediate cyanuric acid. Over a 25-year period, a number of original research papers and reviews have stated that cyanuric acid is metabolized in two steps to the 2-nitrogen intermediate urea. In the present study, allophanate, not urea, was shown to be the 2-nitrogen intermediate in cyanuric acid metabolism in all the bacteria examined. Six different experimental results supported this conclusion: (i) synthetic allophanate was shown to readily decarboxylate to form urea under acidic extraction and chromatography conditions used in previous studies; (ii) alkaline extraction methods were used to stabilize and detect allophanate in bacteria actively metabolizing cyanuric acid; (iii) the kinetic course of allophanate formation and disappearance was consistent with its being an intermediate in cyanuric acid metabolism, and no urea was observed in those experiments; (iv) protein extracts from cells grown on cyanuric acid contained allophanate hydrolase activity; (v) genes encoding the enzymes AtzE and AtzF, which produce and hydrolyze allophanate, respectively, were found in several cyanuric acid-metabolizing bacteria; and (vi) TrzF, an AtzF homolog found in Enterobacter cloacae strain 99, was cloned, expressed in Escherichia coli, and shown to have allophanate hydrolase activity. In addition, we have observed that there are a large number of genes homologous to atzF and trzF distributed in phylogenetically distinct bacteria. In total, the data indicate that s-triazine metabolism in a broad class of bacteria proceeds through allophanate via allophanate hydrolase, rather than through urea using urease.

Allophanate Hydrolase↗

PubMed2005

Rapid and accurate genotyping of YMDD motif variants in the hepatitis B virus genome by an improved reverse dot blot method.

By using the "flow-through hybridization" principle, we developed a new, rapid and accurate reverse dot blot (RDB) method to detect lamivudine resistance-associated YMDD motif variants in hepatitis B virus (HBV) genome. The improved RDB method was very fast at simultaneously detecting HBV YMDD wild-type and mutant motifs. In a blind analysis, 100 samples previously genotyped by DNA clonal sequencing analysis were used to evaluate the sensitivity and specificity of this assay. Conventional restriction fragment length polymorphism (RFLP) data were also used to test our method. In blind experiments, our improved RDB method had an accuracy and specificity of 100%, which was much higher than RFLP, which had an accuracy and specificity of only 83.0%. In clinical detection practice, 49 patients highly suspected of lamivudine resistance were successfully diagnosed by this method. Our improved RDB assay is a simple, rapid, cheap, semiautomatic, accurate, sensitive, and contamination-proof method of detecting lamivudine resistance-associated mutants in the human hepatitis B virus genome.

Amino Acid Motifs↗

PubMed2005

[Quantitative analysis of human globin gene expression in beta-thalassemia using real-time RT-PCR].

Whole blood samples were collected from 100 normal healthy adults, from umbilical cord of 33 newborn infants, 111 individuals with beta-thalassemia minor (beta(T)/beta(A),alphaalpha/alphaalpha) and 39 with beta-thalassemia major (beta(T)/beta(T),alphaalpha/alphaalpha). Prior to quantitative analysis of globin gene expression, DNA was extracted from all blood samples and used for beta-thalassemia genotype analysis. Different types of beta globin gene mutations were analyzed using reverse dot blotting (RDB) method. Total RNA were extracted and subjected to real-time RT-PCR for quantitative measurement of alpha, beta and gamma globin mRNA using three sets of primers and fluorescent-labeled probes, designed according to the sequences of alpha, beta and gamma human globin gene. Real-time RT-PCR was performed in ABI 7700 system. Following the real-time RT-PCR, the mean values of alpha, beta and gamma globin mRNA were calculated and the ratios of alpha/beta, alpha/(beta + gamma ) and gamma /(beta + gamma ) were determined to characterize the relative expression levels of different globin genes among normal adult, infant, beta-thalassemia minor and beta-thalassemia major patients. The resultant data were analyzed using SPSS 10.0 software to determine statistical significance of human globin gene expression among normal controls and beta-thalassemia patients. Due to vast variations of the mean globin gene mRNA levels among different groups, log conversion of alpha/beta + 1, alpha/(beta + gamma ) + 1 and gamma /(beta + gamma ) +1 was used for statistical analyses and intergroup comparison. The alpha/beta globin gene mRNA ratios were determined to be 4.62+/-1.20, 7.81+/-2.89, 13.51+/-5.12, and 188.24+/-374.04 for normal healthy adult (beta(A)/beta(A),alphaalpha/alphaalpha), infant (beta(A)/beta(A),alphaalpha/alphaalpha), beta- thalassemia minor (beta(T)/beta(A),alphaalpha/alphaalpha) and beta-thalassemia major(beta(T)/beta(T),alphaalpha/alphaalpha) respectively. The alpha/(beta+ gamma ) ratios were 4.43+/-1.17, 0.56+/-0.49, 9.62+/-4.37, and 2.14+/-1.58 for normal healthy adult (beta(A)/beta(A),alphaalpha/alphaalpha), infant (beta(A)/beta(A),alphaalpha/alphaalpha), beta- thalassemia minor (beta(T)/beta(A),alphaalpha/alphaalpha) and beta- thalassemia major(beta(T)/beta(T),alphaalpha/alphaalpha) respectively. The gamma /(beta+ gamma ) ratios were 0.04+/-0.03, 0.92+/-0.06, 0.28+/-0.18, and 0.95+/-0.04 for normal healthy adult (beta(A)/beta(A),alphaalpha/alphaalpha), infant (beta(A)/beta(A),alphaalpha/alphaalpha), beta- thalassemia minor (beta(T)/beta(A),alphaalpha/alphaalpha) and beta- thalassemia major (beta(T)/beta(T),alphaalpha/alphaalpha) respectively. Following statistical analyses, the alpha/beta and alpha/(beta+ gamma ) globin gene mRNA ratios were significantly different among four different groups (normal adult, normal infant, beta- thalassemia minor and beta- thalassemia major). The gamma /(beta + gamma ) globin gene mRNA ratio was significantly different among all groups except for between infant and beta- thalassemia major patients. Human beta globin gene mRNA levels decrease progressively and dramatically from normal adults to beta-thalassemia patients with beta-thalassemia major having the lowest levels. On the other hand, the gamma globin gene mRNA levels increase progressively from normal adult to beta-thalassemia patients with beta-thalassemia major having the highest levels. Infants have relatively lower levels of beta but higher levels of gamma globin gene mRNA as compared to those in normal adults. Thus, the relative expression levels of alpha, beta or gamma globin genes varied but inter-related among different ages of normal individuals and different beta-thalassemia genotypes.

Adult↗

PubMed2005

Study on the role of hepatic first-pass elimination in the low oral bioavailability of scutellarin in rats.

In the present study, we compared the systemic exposure of scutellarin following intraportal with intravenous administration to understand the contribution of presystemic hepatic elimination to the low oral bioavailability. Results showed that the hepatic first-pass elimination of scutellarin played an insignificant role in the presystemic elimination of orally administered scutellarin. Moreover, our results suggested that the site of first pass extraction was not the liver, but the gastrointestinal tract.

Animals↗

PubMed2005

[Faster detection of Vibrio parahaemolyticus in foods by FQ-PCR technique].

OBJECTIVE: To establish a rapid and accurate qualitative and quantitative method to detect Vibrio parahaemolyticus in food. METHODS: Primers and Taqman probe were designed according to the sequence of gyrase gene of Vibrio parahaemolyticus. The PCR fragment was cloned into PTM vector and was used as positive template for establishing the criterion curve. The simulated samples, made from negative food samples with Vibrio parahaemolyticus positive strain, were used to evaluate the sensitivity of the PCR reaction. 8 Vibrio parahaemolyticus standard strains and other 24 negative strains (8 strains were Vibrionaceae other than Vibrio parahaemolyticus, the rest 16 strains were none-Vibrionaceae) were treated in the same way to evaluate the specificity. All samples were detected with PE7000 sequence detection system and DA620 fluorescene detection system. RESULTS: FQ-PCR method had good specificity and high sensitivity. All 8 strains of Vibrio parahaemolyticus tested showed positive results while all other 24 strains were negative (8 strains were Vibrionaceae, 16 strain were from different). The correlation was 0.9871 between the concentration of positive template and the quantitative curve circular threshold. The threshold for detecting Vibrio parahaemolyticus in pure culture is 10 cfu/ml, and the threshold is as low as 2 cfu/ml with 16 simulative samples after these samples were incubated for a period of time. By direct quantitative detection for uncultured 16 food samples, the threshold is 100 cfu/g. CONCLUSION: FQ-PCR method has high sensitivity and specificity, and it is a handy and rapid detection method. Comparing with regular PCR method, it is not easily contaminated in operation, and can achieve high sensitivity and specificity with domestic instruments. FQ-PCR method has potential and applied value for detection of pathogenic bacteria in food.

Animals↗