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Biomedical subjects

W Wang

Publications and source records attributed to W Wang.

At least 109 records · Page 6Linked to original sources
PubMed2003

Randomized clinical trial of Ligasure versus conventional surgery for extended gastric cancer resection.

BACKGROUND: The Ligasure Vessel Sealing System is a haemostatic device designed primarily for use in abdominal surgery. Randomized trials have demonstrated that it is safe and quick for haemorrhoidectomy, but there is no evidence that it confers any advantage in complicated gastrointestinal surgery. The aim of the present study was to examine the value of the Ligasure system in extended lymph node dissection (D2) during gastrectomy for cancer in a randomized clinical trial. METHODS: D2 gastric resection performed with the Ligasure system was compared with resection using conventional haemostatic methods in a prospective randomized trial. Central randomization (40 patients in each group) was performed after a staging laparotomy. The main outcome measures were operating time, intraoperative blood loss, postoperative course and complications. RESULTS: Ligasure was associated with less intraoperative blood loss (mean(s.d.) 142(73) versus 239(124) ml; P = 0.001) and a shorter operating time (mean(s.d.) 169(25) versus 222(28) min; P = 0.001) than conventional operation. Postoperative drainage fluid volumes were greater in the Ligasure group (mean(s.d.) 1577(940) versus 886(542) ml; P = 0.020). There were no differences in postoperative complications or hospital stay. CONCLUSION: The Ligasure Vessel Sealing System is safe for use in extended lymph node dissection for gastric cancer, and is associated with a shorter operating time and decreased blood loss compared with conventional haemostatic techniques.

Adenocarcinoma↗
PubMed2003

Prenatal diagnosis of cephalothoracopagus janiceps disymmetros using three-dimensional power Doppler ultrasound and magnetic resonance imaging.

We report the prenatal imaging findings of a rare case of cephalothoracopagus janiceps disymmetros diagnosed at 28 weeks' gestation. Two-dimensional ultrasound and magnetic resonance imaging demonstrated janiceps conjoined female twins with a single fused cranial vault, duplicated cerebra, two faces, four eyeballs, a fused thorax, two hearts, two thoracic spines, eight limbs and polyhydramnios. Three-dimensional and power Doppler ultrasound established the definitive classification of cephalothoracopagus conjoined twins and displayed the shared circulation between the two separate hearts.

Abnormalities, Multiple↗
PubMed2003

The SWI/SNF family of ATP-dependent chromatin remodelers: similar mechanisms for diverse functions.

The SWI/SNF family of complexes utilizes the energy of ATP hydrolysis to remodel chromatin structures, thereby allowing transcription factors to gain access to DNA. Recent studies suggest that these remodelers also participate in other DNA metabolic reactions such as replication and viral integration, and even in control of cell growth and tumor suppression. The SWI/SNF remodelers can be classified into at least two distinct subfamilies: one includes human BAF (also known as hSWI/SNF-A) and yeast SWI/SNF; the other comprises human PBAF (hSWI/SNF-B) and yeast RSC. Although both types of complexes have similar subunit composition and chromatin remodeling activity in vitro, they cannot replace each other during transcription mediated by specific activators. Thus, each remodeler probably works with a specific set of activators during gene activation. The availability of distinct types of remodelers can allow cells to regulate expression of a specific group of genes by modulating the activity of corresponding remodelers.

Adenosine Triphosphate↗
PubMed2003

Molecular characterization of a distinct potyvirus from whitegrass in China.

Apotyvirus isolated from perennial whitegrass ( Pennisetum centrasiaticum Tzvel.) in North China was characterized at the molecular level. The 3' terminal nucleotide (nt) sequence of 1669 nt of the viral RNA genome has been determined, which covered the coding region of the C-terminal part of the large nuclear inclusion protein (NIb, RNA polymerase), capsid protein (CP) gene and the 3' nontranslated region (NTR). The CP gene consisted of 909 nt (including the stop codon) encoding 302 amino acid residues, and the 3' NTR was 241 nt in length excluding the polyadenylated tract. Sequence comparison of the amino acids of CPs showed that this virus was most closely related to Sorghum mosaic virus and Maize dwarf mosaic virus with percent identities of 77% to 78% while that of the 3' NTRs suggested that it was most closely related to Zea mosaic virus with identity of 72%. This virus isolate was to some extent closely related to other members of the Sugarcane mosaic virus subgroup of potyviruses for the CP amino acid sequences. Phylogenetic analyses of the sequences indicated that this virus isolate represented a distinct potyvirus, and the name Pennisetum mosaic virus (PenMV) is proposed.

Capsid Proteins↗
PubMed2003

Upregulation of IL-2 but not IL-15 by allorecognition in human mixed lymphocyte culture.

The redundant and pleiotropic effects of cytokines in transplant models have been shown both in vitro and in vivo. IL-2 is clearly not necessary for allograft rejection, possibly due to upregulated IL-15. We examined IL-15 expression using mixed lymphocyte culture (MLC) as an allorecognition model. IL-2 and IL-15 levels were measured by enzyme-linked immunoassay after 120 hours of culture. Cell proliferation in MLC was examined using [(3)H]thymidine uptake in the presence of either anti-IL-2Ralpha chain antibody or anti-IL-2Rgamma chain antibody. While IL-2 was detectable in cell supernates of MLC, IL-15 was not. Stimulation with an Anti-IL-2 gamma chain antibody which blocks the IL-2 gamma chain, a common unit in IL-2/IL-15 receptors, failed to produce additive antiproliferative effects after maximum inhibition by anti-IL-2alpha chain antibody, which is specific for IL-2. In conclusion, experiments in the MLC model suggest that allorecognition upregulates IL-2 but not IL-15 expression.

Cell Division↗
PubMed2003

Increased frequency of the mannose-binding lectin LX haplotype in Chinese systemic lupus erythematosus patients.

Mannose-binding lectin (MBL) is an important complement-activating protein of the human immune system. As a result of one of three structural gene mutations in exon 1 (variants B, C and D) and/or the presence of a low-efficiency promoter polymorphism, MBL deficiency may be associated with increased susceptibility to infectious diseases and to autoimmune disorders, including systemic lupus erythematosus (SLE). Using a combined approach of heteroduplex generator and polymerase chain reaction, a systematic search for mutations in exon 1 and the promoter region of the MBL gene was performed in a Chinese study population comprising 41 SLE patients and 111 healthy controls. Two alleles, a wild-type allele A and a variant allele B (a previously reported mutation of GGC to GAC at codon 54), were identified in MBL exon 1. The frequency of the B allele (0.15) was higher in the SLE patients than in the healthy controls (0.09), but the difference did not attain statistical significance (P > 0.05). However, for two polymorphisms at positions -550 and -221 in the promoter region, the frequency of the low-MBL-producing haplotype (LX) in the patients (0.2073) was significantly higher than that in the controls (0.0855) (P = 0.003, relative risk = 2.79). Our results suggest that the LX haplotype represents a strong risk factor among Chinese SLE patients. Although of lesser importance, the MBL B allele also may be a risk component in the developing process of SLE in Chinese patients.

Adolescent↗
PubMed2003

Disseminated trichosporonosis in China.

A 20-year-old female patient presented with erythematous plaques on the nose which were progressively spreading to the trunk and the extremities, sometimes with erosions and scars. The patient was misdiagnosed as having seborrhoeic dermatitis and subacute cutaneous lupus erythematosus. The histopathological biopsy revealed mycotic infectious granuloma. Samples taken from skin lesions and other locations grew Trichosporon asahii in cultures. The identification was confirmed by molecular biological methods. The patient was treated successfully with liposomal amphotericin B in combination with fluconazole orally.

Adult↗
PubMed2003

Effect of intravenous endotoxin on blood cell profiles of broilers housed in cages and floor litter environments.

Commercial broilers are constantly exposed to airborne microorganisms and endotoxin (lipopolysaccharide, LPS). It has been shown that microbial contamination of the air was higher in broiler houses using floor litter than in broiler houses using netting-type floors. The current study evaluated the effect of housing conditions on blood leukocyte profiles and tested the hypothesis that, when compared to broilers reared in clean stainless steel cages (Cage group), broilers raised on floor litter (Floor group) should experience a higher environmental challenge and have a desensitized immune system that may exhibit better tolerance/resistance to subsequent intravenous LPS challenge. Hematological parameters were evaluated prior to and following i.v. administration of 1 mg/kg BW Salmonella typhimurium LPS (dissolved at 1 mg/0.25 mL in PBS) or i.v. injection of 0.25 mL/kg BW PBS alone. The results showed that prior to LPS/PBS injection, broilers in the cage group had higher heterophil and monocyte concentrations, a higher B cell percentage within the lymphocyte population, and a higher heterophil to lymphocyte (H:L) ratio in the blood. The i.v. LPS injection resulted in 25% mortality in the cage group and 42% mortality in the floor group within 8 h post-injection. LPS reduced the concentrations of total white blood cells (WBC) and all differential WBC except eosinophils and increased thrombocyte concentrations within 1 h post-injection in both groups. All of these values returned to their respective pre-injection levels within 48 h post-injection in the surviving birds. The two groups exhibited similar overall hematological changes after LPS injection except that the cage group showed a higher H:L ratio at 8 h post-injection and a lower B-cell percentage within the lymphocyte population at 48 h post-injection when compared with the floor group. We concluded that the immune systems of broilers reared on floor litter were desensitized and exhibited less pronounced leukocyte responses to i.v. LPS when compared with those of broilers reared in clean stainless steel cages. However, such desensitization of the immune system did not help broilers survive subsequent i.v. LPS challenge.

Air Microbiology↗
PubMed2003

Broiler survivors of intravenous micro-particle injections: evaluation of growth, livability, meat quality, and arterial blood gas values during a cyclic heat challenge.

When broilers are exposed to high ambient temperatures, their cardiac output can increase by 20 to 50%. Previously, we developed an intravenous micro-particle injection technique to select broilers having a cardiopulmonary capacity capable of accommodating increases in cardiac output associated with fast growth and cool temperatures. In the present study, male broilers were injected at 18 to 20 d of age with cellulose micro-particles sufficient to trigger >50% mortality by 35 d of age. The survivors of micro-particle injections (cellulose survivors) and saline-injected flock mates (control group) were exposed to a moderate cyclic heat challenge (peak temperature of 35 to 37 degrees C) beginning on d 36 and continuing through d 57. We tested the hypothesis that if the cellulose survivors represent the population cohort having the most robust cardiopulmonary capacity, then during a subsequent heat challenge these survivorspotentially may perform better than their unselected flock mates. Based on data combined from two independent experiments, the cellulose survivors exhibited improved livability and body weight gain when compared with their unselected flock mates during the cyclic heat challenge. Meat quality characteristics did not differ between the groups. In a third experiment, cellulose survivors and saline-injected male broilers were reared at thermoneutral temperatures or were exposed to a cyclic heat challenge beginning on d 36. Arterial blood samples were collected from unanesthetized birds at 47 to 49 d of age and were analyzed for pH, partial pressure of CO2, bicarbonate, partial pressure of O2, and saturation of hemoglobin with O2. The blood gas values for the cellulose survivors and saline-injected broilers did not differ within a temperature regimen, regardless of whether the broilers were chronically acclimated to heat or were exposed to an acute heat challenge at the end of the experiment. The cellulose survivors did not differ in susceptibility to panting-induced respiratory alkalosis or hypoxemia when compared with their saline-injected flock mates. Overall, these observations indicate that selection for a robust cardiopulmonary capacity can confer advantages in growth and livability without affecting meat quality when broilers are exposed to a moderate heat challenge.

Animals↗
PubMed2003

Pulmonary and hematological inflammatory responses to intravenous cellulose micro-particles in broilers.

When injected intravenously, cellulose micro-particles become lodged in pulmonary arterioles. The current study investigated the systemic and pulmonary inflammatory responses triggered by cellulose micro-particles at 3, 24, and 48 h postinjection in 6-wk-old broilers. Proportions and concentrations of circulating white blood cells were assessed in saline-injected (control group) and cellulose-injected (particle group) birds. Hematoxylin-eosin (HE)-stained cross-sections of the lungs were used to count the number of granuloma/lymphocyte aggregates, which is indicative of the severity of the inflammatory response to the trapped particles. The cellular components of the aggregates were identified by immunohistochemical staining of frozen cross sections of the lungs. Results showed that cellulose micro-particles trapped in the pulmonary vasculature initiated a dynamic, localized inflammatory response within the surrounding lung parenchyma. Monocytes and basophilic granulocytes closely surrounded the particles. CD4, CD8, TCR1, TCR2, and TCR3 subsets of T cells and B cells were present in the outer rim of the granuloma/lymphocyte aggregates. Circulating total white blood cell (WBC, leukocytes) concentrations were similar in both groups at all times postinjection, whereas at 48 h post-injection the percentages of eosinophils and basophils among circulating WBC were higher in the particle group than in the control group (P < or = 0.05). The circulating monocyte concentration also increased within 24 h postinjection (P < or = 0.05). These observations demonstrate that cellulose micro-particles trapped in the pulmonary vasculature initiated acute focal inflammatory responses in the lungs and that the proportions of WBCs in the blood are modulated within 48 h postinjection.

Animals↗
PubMed2003

Estimating predictors for long- or short-term survivors.

Suppose that the response variable in a well-executed clinical or observational study to evaluate a treatment is the time to a certain event, and a set of baseline covariates or predictors was collected for each study patient. Furthermore, suppose that a significant number of study patients had nontrivial, long-term adverse effects from the treatment. A commonly posed question is how to use these covariates from the study to identify future patients who would (or would not) benefit from the treatment. In this article, we present "point" and "interval" estimates for the set of covariate or predictor vectors associated with a specific patient survival status, e.g., long- (or short-) term survival, in the presence of censoring. These estimates can be easily displayed on a two-dimensional plane, even for the case with high-dimensional covariate vectors. These simple numerical and graphical procedures provide useful information for patient management and/or the design of future studies, which are key issues in pharmacogenomics with genetic markers. The new proposal is illustrated with a data set from a cancer study for treating multiple myeloma.

Biometry↗
PubMed2003

Electrical characterization of metal-molecule-silicon junctions.

Direct assembly of molecules onto silicon surfaces is of particular interest for potential employment in hybrid organic-semiconductor devices. In the study we report here, aryl diazonium salts were used to assemble covalently bound molecular groups on a hydride-passivated, oxide-free n-type Si(111) surface. The reaction of 4-(trimethylsilylethynyl)benzenediazonium tetrafluoroborate generates a molecular layer of 4-(trimethylsilylethynyl)phenylene (TMS-EP) on the n++-Si(111) surface. The monolayer modifies the electrical properties of the interface and exhibits nonlinear current-voltage characteristics, as compared with the ohmic behavior observed from metal-n++-Si(111) junctions. The result of current-voltage measurements at variable temperatures (from 300 to 10 K) on samples made with the TMS-EP molecule does not show significant thermally-activated transport, indicating that tunneling is the dominant transport mechanism. The measured data is compared to a tunneling model.

Electric Conductivity↗
PubMed2003

Acute acalculous cholecystitis in China.

In order to study the clinical characteristics of patients with acute acalculous cholecystitis (AAC) in China, we retrospectively analysed the epidemiology, clinical manifestations and treatment of hospitalised cases with AAC in our hospital between January 1991 and October 1998, and compared the results with western reports. Most AAC cases in our series were younger than 60 years, and there was no significant difference between males and females. Their clinical manifestations were usually not serious. Only one patient suffered complications. The rate of complications and mortality was lower than those in western countries. All patients were treated and recovered; none needed an emergency operation and there were no deaths.

Acute Disease↗
PubMed2002

MoeA, an enzyme in the molybdopterin synthesis pathway, is required for rifamycin SV production in Amycolatopsis mediterranei U32.

Rifamycin SV contains one amide nitrogen atom at its C(7)N moiety. Earlier labeling studies suggested that nitrogen might be incorporated from a pathway involved in a molybdenum-dependent nitrate reductase. However, no genetic evidence is available thus far. The structural gene moeA, which is involved in molybdopterin synthesis in various organisms, has been cloned from rifamycin SV-producing Amycolatopsis mediterranei strain U32. The amino acid sequence deduced from the moeA gene showed significant similarity to members of the MoeA protein family and contains all the structural features that are highly conserved in the putative functional domains of MoeA proteins. Southern hybridization showed that there is only one moeA gene in the A. mediterranei genome. To further investigate the possible physiological function of the moeA gene, a double crossover gene replacement was achieved by inserting an aparmycin resistance gene into moeA in the A. mediterranei U32 chromosome. Phenotype analysis showed that the moeA gene is required for A. mediterranei growth in a minimal medium with nitrate as sole nitrogen source, possibly because nitrate reductase activity is diminished due to disruption of the moeA gene. Compared to the wild type strain, moeA-disrupted mutants lost 95% of their rifamycin SV production capacity in complex fermentation media. The results demonstrate that the moeA gene is necessary for rifamycin SV production in A. mediterranei, and that the nitrogen assimilation pathway involved in nitrate reductase is the major pathway for the genesis of the amide nitrogen atom in the rifamycin SV molecule.

Actinomycetales↗