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Biomedical subjects

R Yang

Publications and source records attributed to R Yang.

At least 73 records · Page 4Linked to original sources

A cost and performance evaluation of disposable and reusable biopsy forceps in GI endoscopy.

BACKGROUND: Biopsy forceps are widely used in gastrointestinal endoscopy, and yet few data exist on the usage and costs associated with disposable versus reusable forceps. METHODS: We prospectively measured the costs and operational performance of disposable and reusable forceps in 200 biopsy sessions; 100 sessions were performed using disposable forceps and 100 sessions were performed using reusable forceps. Total cost per use of the reusable forceps, including acquisition costs plus the costs of reprocessing per established guidelines, was determined. At the end of the study, the reusable forceps were disassembled to determine the cause of mechanical failures. RESULTS: The total cost per use of the disposable forceps was $38. For the reusable forceps, the acquisition cost per forceps was $415 and the total reprocessing cost was $16.56 +/- 0.07 per forceps. For 10, 15 and 20 uses, reusable forceps costs were $58.06, $44.23, and $37.31, respectively. Reusable forceps malfunction at 11 to 15 uses was 5%; at 16 to 20 uses was 25%; and at 21 to 25 uses reached 80% (p < 0.001). Dismantling of the reusable forceps at the end of the study demonstrated coiled sheath kinking, rust in the forceps closure mechanism, bent spikes, and biomaterial contamination. CONCLUSIONS: Up to 15 to 20 uses, disposable and reusable forceps costs were similar. If reusable forceps are used more than 20 times, then they are less expensive. However, in this range of uses, reusable biopsy forceps performance diminishes. With disposable biopsy forceps costing less than $40, cost differences between reusable and disposable forceps are minimal.

Biopsy↗

Distinctness of spore and vegetative cellular fatty acid profiles of some aerobic endospore-forming bacilli.

A gas chromatographic analysis method was employed to determine the cellular fatty acid (CFA) profiles of spores and vegetative cells of some aerobic endospore-forming bacilli. The harvests of experimental strains were processed to obtain pure spores and acquire whole cell fatty acid methyl esters for the subsequent gas chromatographic analysis, and the corresponding vegetative cells were set as control. Evaluation of reproducibility of spore CFA components revealed that, provided under standardized experimental procedure, spore CFA composition was stable enough for research purposes. Fatty acids recovered in spores in greater quantities were saturated branched-chain acids containing 15 and 17 carbon atoms, similar to the vegetative cells. Commonly, the proportions of saturated branched-chain acids in spores were greater than in vegetative cells. The dendrograms obtained by cluster analysis provided some meaningful taxonomic information of the experimental strains. The fatty acids analysis of spores seems to be a promising supplementary tool for the chemotaxonomic research of aerobic endospore-forming bacilli.

Bacillaceae↗

Autoimmunity to munc-18 in Rasmussen's encephalitis.

Rasmussen's encephalitis (RE) is a rare disease of the central nervous system characterized by severe epileptic seizures, progressive degeneration of a single cerebral hemisphere, and autoimmunity directed against glutamate receptor subunit, GluR3. We report here the identification of high-titer autoantibodies directed against munc-18 in the serum of a single patient with RE previously shown to have anti-GluR3 antibodies. Munc-18 is an intracellular protein residing in presynaptic terminals, which is required for secretion of neurotransmitters. These findings are consistent with the possibility of intermolecular epitope spreading between GluR3, a postsynaptic cell surface protein, and munc-18, a presynaptic intracellular protein. Immune attack on these two proteins, which participate at distinct steps of synaptic transmission, could act in an additive or synergistic manner to impair synaptic function and lead to seizures and neuronal death.

Amino Acid Sequence↗

The mechanism of nitric oxide and/or superoxide cytotoxicity in endothelial cells.

We examined the mechanism of nitric oxide (NO) and/or superoxide (O2-)-induced cytotoxicity and the importance of thiols in endothelial cells by treating the cells with superoxide dismutase (SOD), catalase (CAT) and hemoglobin (Hb). Pyrogallol, a O2 generator and precursor of hydrogen peroxide (H2O2), had potent cytotoxic effects on the endothelial cells, but this effect was completely abolished by SOD/CAT. Hb, a NO scavenger, protected the endothelial cells from sodium nitroprusside-induced cytotoxicity. The cytotoxic effect of 3-morpholinosydnonimine (SIN-1), which is thought to form peroxynitrite (ONOO-) as a simultaneous O2- and NO generator, was completely blocked by SOD/CAT or Hb. On the other hand, pretreatment of endothelial cells with diethylmaleate, a glutathione depleter, aggravated the cytotoxicity induced by SIN-1, which was prevented by addition of exogenous glutathione and/or SOD/CAT. These data suggest that the cytotoxicity induced by NO, O2- and ONOO- can be blocked by glutathione, and that this is an important cellular protective mechanism against these reactive oxygen species.

Animals↗

A new cembranolide from the soft coral Sinularia capillosa.

A new cembranolide, capillolide (1), and three known cembranolides were isolated from the soft coral Sinularia capillosa collected from the South China Sea. Their structures and the relative stereochemistry of 1 were deduced on the basis of spectroscopic methods.

Animals↗

Glucose limitation induces GCN4 translation by activation of Gcn2 protein kinase.

Phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF-2alpha) is a well-characterized mechanism regulating protein synthesis in response to environmental stresses. In the yeast Saccharomyces cerevisiae, starvation for amino acids induces phosphorylation of eIF-2alpha by Gcn2 protein kinase, leading to elevated translation of GCN4, a transcriptional activator of more than 50 genes. Uncharged tRNA that accumulates during amino acid limitation is proposed to activate Gcn2p by associating with Gcn2p sequences homologous to histidyl-tRNA synthetase (HisRS) enzymes. Given that eIF-2alpha phosphorylation in mammals is induced in response to both carbohydrate and amino acid limitations, we addressed whether activation of Gcn2p in yeast is also controlled by different nutrient deprivations. We found that starvation for glucose induces Gcn2p phosphorylation of eIF-2alpha and stimulates GCN4 translation. Induction of eIF-2alpha phosphorylation by Gcn2p during glucose limitation requires the function of the HisRS-related domain but is largely independent of the ribosome binding sequences of Gcn2p. Furthermore, Gcn20p, a factor required for Gcn2 protein kinase stimulation of GCN4 expression in response to amino acid starvation, is not essential for GCN4 translational control in response to limitation for carbohydrates. These results indicate there are differences between the mechanisms regulating Gcn2p activity in response to amino acid and carbohydrate deficiency. Gcn2p induction of GCN4 translation during carbohydrate limitation enhances storage of amino acids in the vacuoles and facilitates entry into exponential growth during a shift from low-glucose to high-glucose medium. Gcn2p function also contributes to maintenance of glycogen levels during prolonged glucose starvation, suggesting a linkage between amino acid control and glycogen metabolism.

DNA-Binding Proteins↗

Methylation of the cyclin A1 promoter correlates with gene silencing in somatic cell lines, while tissue-specific expression of cyclin A1 is methylation independent.

Gene expression in mammalian organisms is regulated at multiple levels, including DNA accessibility for transcription factors and chromatin structure. Methylation of CpG dinucleotides is thought to be involved in imprinting and in the pathogenesis of cancer. However, the relevance of methylation for directing tissue-specific gene expression is highly controversial. The cyclin A1 gene is expressed in very few tissues, with high levels restricted to spermatogenesis and leukemic blasts. Here, we show that methylation of the CpG island of the human cyclin A1 promoter was correlated with nonexpression in cell lines, and the methyl-CpG binding protein MeCP2 suppressed transcription from the methylated cyclin A1 promoter. Repression could be relieved by trichostatin A. Silencing of a cyclin A1 promoter-enhanced green fluorescent protein (EGFP) transgene in stable transfected MG63 osteosarcoma cells was also closely associated with de novo promoter methylation. Cyclin A1 could be strongly induced in nonexpressing cell lines by trichostatin A but not by 5-aza-cytidine. The cyclin A1 promoter-EGFP construct directed tissue-specific expression in male germ cells of transgenic mice. Expression in the testes of these mice was independent of promoter methylation, and even strong promoter methylation did not suppress promoter activity. MeCP2 expression was notably absent in EGFP-expressing cells. Transcription from the transgenic cyclin A1 promoter was repressed in most organs outside the testis, even when the promoter was not methylated. These data show the association of methylation with silencing of the cyclin A1 gene in cancer cell lines. However, appropriate tissue-specific repression of the cyclin A1 promoter occurs independently of CpG methylation.

Animals↗

Effects of exercise training on cardiac function, gene expression, and apoptosis in rats.

This study determined the effects of exercise training on cardiac function, gene expression, and apoptosis. Rats exposed to a regimen of treadmill exercise for 13 wk had a significant increase in cardiac index and stroke volume index and a concomitant decrease in systemic vascular resistance compared with both age-matched and body weight-matched sedentary controls in the conscious state at rest. In exercise-trained animals, there was no change in the expression of several marker genes known to be associated with pathological cardiac adaptation, including atrial natriuretic factor, beta-myosin heavy chain, alpha-skeletal and smooth muscle actins, and collagens I and III. Exercise training, however, produced a significant induction of alpha-myosin heavy chain, which was not observed in rats with myocardial infarction. No histological features of cardiac apoptosis were observed in the treadmill-trained rats. In contrast, apoptotic myocytes were detected in animals with myocardial infarction. In summary, exercise training improves cardiac function without evidence of cardiac apoptosis and produces a pattern of cardiac gene expression distinct from pathological cardiac adaptation.

Actins↗

Anticonvulsion effect of acupuncture might be related to the decrease of neuronal and inducible nitric oxide synthases.

To measure the levels of hippocampal nitric oxide synthase isoforms in penicillin induced epilepsy and to test the effect of electroacupuncture (EA) on changes of theses levels during epilepsy, we injected penicillin into rat hippocampus to make an epilepsy model and performed electroacupuncture treatment on "Feng Fu" (DU 16) and "Jin Suo" (DU 8) points in Wistar rats. Nitric Oxide synthase (NOS) mRNA levels of rat hippocampus were determined by reverse transcription-polymerase chain reaction (RT-PCR). The neuronal nitric oxide synthase (nNOS) mRNA markedly increased (P<0.01) and inducible nitric oxide synthase (iNOS) mRNA significantly emerged during epilepsy, whereas no significant change in epithelial nitric oxide synthase (eNOS) mRNA was observed. EA inhibited the epilepsy and decreased nNOS (P<0.01) and iNOS (P<0.01) correspondingly but had no effect on the amount of eNOS mRNA. The data suggest that penicillin-induced epilepsy caused an increase in nNOS and iNOS, and the EA anticonvulsant effect might be related to the decrease of these nitric oxide synthases.

Animals↗

Pathogenesis and management of chronic idiopathic thrombocytopenic purpura: an update.

Idiopathic thrombocytopenic purpura (ITP) is a disorder characterized by platelet destruction caused by an antiplatelet autoantibody that results in platelet phagocytosis via the reticuloendothelial system. The condition will become chronic in 10% to 20% of children with ITP and almost all adult ITP patients. The expert panel established in 1994 by the American Society of Hematology extensively reviewed ITP-related articles before 1995 and published practice guidelines. This publication is of great help in regard to research and management of ITP. However, the pathogenesis of chronic ITP has not been fully elucidated, and its management is primarily empirical. This review focuses mainly on the articles published after 1995, including some experiences in China.

Autoantibodies↗

Differences in virulence between two Candida albicans strains in experimental keratitis.

PURPOSE: To study the differences in disease caused by two wild-type strains of Candida albicans in a model of contact lens-facilitated keratitis in rabbits. METHODS: Two strains, SC5314 and VE175, were examined. Standardized inocula were placed on the debrided corneal surface of one eye in Dutch belted rabbits and covered with a contact lens. A temporary tarsorrhaphy was opened after 24 hours with removal of the contact lens. Six days later, corneas were photographed and animals killed. Corneas were bisected with one half for quantitative isolate recovery and the other for stromal penetration by hyphae. RESULTS: Strain SC5314 was significantly more virulent. The mean hyphal penetration into the cornea was 24.4% +/- 8.5% of the corneal thickness, and in three of six corneas hyphae penetrated through the entire cornea. In contrast, for VE175, the mean hyphal penetration was 2.6% +/- 1.2%. The difference between these two strains was statistically significant (P = 0.0297). Hyphae did not penetrate into the deep layers of the cornea in any of the six rabbits infected with VE175. The grading of clinical disease was consistent with histology, in that strain SC5314 caused more severe infection than VE175 and the difference was statistically significant (P = 0.0048). There was no difference in isolate recovery. CONCLUSIONS: Wild-type strains of C. albicans can differ significantly in virulence as measured by depth of fungal invasion into corneas and clinical evaluation of infection. Further characterization of the intrinsic genetic differences between such strains may help identify factors responsible for fungal virulence.

Animals↗

[Establishment of cisplatin-induced multidrug resistant human epithelial ovarian cancer cell line 3AO/cDDP and its expressions of multidrug resistance proteins].

OBJECTIVE: To establish multidrug resistant ovarian cancer cell line 3AO/cDDP by exposing parent cell line intervally and repeatedly to high-level concentration of cisplatin, and to detect expressions of lung resistance protein (LRP), multidrug resistance-associated protein(MRP) and P-glycoprotein (P-gp). METHODS: Using the corresponding dose calculated from clinical chemotherapy, we established 3AO/cDDP, with 3AO exposed intervally and repeatedly to high-level concentration of cisplatin at 10 micrograms/ml for 24 hours each time; LRP, MRP and P-gp expressions were detected with flow cytometry(FCM). RESULTS: 3AO/cDDP was established after 4.5 months with stable resistance and the drug resistant index was 1.62 which was similar to clinical resistance degree. Low expression levels of MRP and P-gp were found in both 3AO and 3AO/cDDP, and no statistical difference between the two lines (P > 0.05). However, LRP expression level in 3AO/cDDP was significantly higher than that in 3AO with FCM detection (P < 0.01). CONCLUSIONS: 3AO/cDDP, induced by exposing 3AO to high-level concentration of cisplatin intervally and repeatedly, is an ideal model for investigation of cisplatin resistance. Cisplatin resistance in 3AO/cDDP could be related to high LRP expression and be not associated with MRP or P-gp.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

[High-affinity glutamate transporters].

High-affinity glutamate transporters are located predominantly in the plasma membrane of neurons and glial cells. They have the capacity to take up glutamate from the extracellular space into the cells against its concentration gradient to terminate glutamatergic transmission and to keep the extracellular glutamate concentration at low levels to protect neurons from glutamate toxicity. As glutamate transporters were recently cloned, the research in this field has been greatly advancing. This article focuses on recent progress in the study of molecular structure, distribution of expression, physiological significance, structure-function relationships of these transporters.

Amino Acid Transport System X-AG↗

Identification of a mutation hotspot in exon 8 of Wilson disease gene by cycle sequencing.

OBJECTIVE: To screen for mutation hotspot of Wilson disease (WD) gene in Chinese population. METHODS: Cycle sequencing was used to detect mutation in exon 8 of WD gene in 30 patients with Wilson disease. RESULTS: The same missense mutation, Arg779Leu, was identified in 14 WD patients, four of whom were homozygous and the other heterozygous for this mutation. The frequency of this mutation in Chinese patients was 30%. CONCLUSION: The codon 779 (CCG-->CTG) of exon 8 of WD gene was one of mutation hotspots in Chinese.

Adenosine Triphosphatases↗

[Effect of gandou decoction on copper metabolism of skin fibroblast of hepatolenticular degeneration model].

OBJECTIVE: To explore the cytological mechanism of Gandou Decoction (GDD) in treating hepatolenticular degeneration (HLD). METHODS: Twenty-three in vitro models of cultured skin fibroblast of HLD were established to observe the intracellular change of microelements (Cu2+, Zn2+, etc.) content before and after adding rabbit's serum containing GDD. RESULTS: After being treated with GDD contained serum for 24 hours, the intracellular content of Cu2+ decreased from (80.94 +/- 34.76) ng/mg to (46.90 +/- 22.14) ng/mg, P < 0.01, while that of Zn2+ increased from (140.43 +/- 33.81) ng/mg to (151.43 +/- 37.83) ng/mg, P < 0.01. CONCLUSION: GDD is quite effective in removing the intracellular copper and increasing the intracellular zinc.

Adolescent↗

[Epidemiological feature on diabetes mellitus among permanent inhabitant in the Special Economic Zone of Shenzhen].

OBJECTIVE: To investigate prevalence and relevant factors of diabetes mellitus among permanent inhabitant in Shenzhen. METHODS: The prevalence of 8 200 inhabitants aged over 20 in Shenzhen was studied. Blood glucose was determined by glucose - oxidase method. RESULTS: According to the WHO diagnostic standard, the prevalence rates of DM and IGT were 4.23% and 11.94% respectively. The prevalence increased apparently with age. The history of clan and overweight were related to the prevalence rates of DM and IGT. The people of DM and IGT were mostly accompanied with high levels of triglyceride, total cholesterol, uric acid, creatinine and low level of high dense lipoprotein (HDL). CONCLUSION: The history of clan, old age, overweight and higher fattiness were found risk factors of DM and IGT.

Adult↗

[Homogeneity study on the Streptococcus suis isolated from human and swine].

OBJECTIVE: To identify S. suis and to evaluate the homogeneity of isolates of S. suis from human and swine. METHODS: Culture, morphology, API biochemical tests and serum coagulate tests were used. All the 7 strains of streptococcus were confirmed to be S. suis serotype 2. Two strains and 1 strain were isolated from blood and cerebrospinal fluid (CSF) of patients, respectively, while the other 4 strains were obtained from the infected swine or their corpses. Seven strains of S. suis serotype 2 and reference strain SS2 were analyzed by randomly amplified polymorphic DNA analysis with six primers and Rep PCR with four primers and thalli fatty acid profile analysis. Cluster and principal compound analysis of results were performed with RAPD, Phylip and Treeview software. RESULTS: By analysis on RAPD patterns, a close relationship among 7 strains of S. suis serotype 2 and reference strain SS2 was discovered. Human-born strains and swine-born strains exhibit similar RAPD patterns. There was a same clonal relationship between strains originated from the blood and CFS of the patients. These results were confirmed by thalli fatty acid profile to have genotypic and phenotypic identity. CONCLUSION: Homogeneity exists among the 7 strains and reference strain SS2.

Animals↗

[Effects of oral calcium supplementation on blood pressure in population].

OBJECTIVE: To assess the effects of oral intake of calcium lactate tablet on blood pressure and serum levels of sodium, potassium, calcium and phosphors. METHODS: In a rural area with natural population with higher average blood pressure and prevalence of hypertension, and with high salt and low calcium intake in diet in Yu County, Shanxi Province, 112 volunteers aged 30 to 64 years were selected based on a mass screening for hypertension, and randomized into trial and control groups with double blinding, taking calcium lactate tablets (800 mg of calcium daily) and placebo respectively for five weeks. Ninety-eight of them complied with the medical order completely, 39 males and 59 females, and were followed-up for systolic (SBP) and diastolic blood pressure (DBP), and their fasting venous blood specimen and 8-hour nocturnal urine specimens were collected. Twenty-four-hour diet recall was obtained for three consecutive days from all of them. RESULTS: Reduction of 4.7 mm Hg (0.62 kPa) and 2.7 mm Hg (0.36 kPa) in systolic and diastolic blood pressure, respectively in the trial group was observed, as compared with that in control one, with P-values of 0.027 and 0.074, respectively, after 35 days of treatment. The higher their baseline BP level, the greater reduction of their BP after treatment. Urinary excretion of calcium increased and serum level of phosphorus reduced after oral administration of calcium. CONCLUSION: In an area with higher prevalence of hypertension and with high salt and low calcium intake in diet, change in diet composition or supplementation with calcium could reduce their average blood pressure and prevent them from hypertension for those with mild and moderate hypertension and in high risk with higher blood pressure.

Administration, Oral↗