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Biomedical subjects

X Weng

Publications and source records attributed to X Weng.

At least 19 recordsLinked to original sources
PubMed1999

Imaging the functioning human brain.

One of the most exciting methodological advances for brain research field arises in functional brain imaging, which enables us to localize and characterize neural activity and biochemical events in the living human brain. Recently developed event-related functional MRI makes it possible to visualize the brain activity associated with cognitive processes with the temporal resolution of the hemodynamic response. In addition, the high sensitivity and selectivity of positron-emission tomography allow us to probe the neurochemical processes at the molecular level. Positron-emission tomography also has been applied to investigate the effects of therapeutic drugs as well as the effects of drugs of abuse.

Brain↗
PubMed1999

Contribution of the -455G/A polymorphism at the beta-fibrinogen gene to erythrocyte aggregation in patients with coronary artery disease.

BACKGROUND: A high level of red blood cell (RBC) aggregation has been consistently found in patients with coronary artery disease (CAD) in case-control studies. Plasma fibrinogen has been shown to promote RBC aggregability. The purpose of this study was to investigate the influence of the genetic variability of the beta-fibrinogen gene on RBC aggregation in patients with CAD. METHODS AND RESULTS: The genotype of the beta-fibrinogen gene locus was determined by polymerase chain reaction using the restriction enzyme HaeIII for a G to A substitution at position -455 upstream from the transcriptional start site in 135 French Canadians with premature CAD (age: 51+/-7 years). Indices measuring the RBC aggregation kinetics (S10) and shear resistance of the aggregates (gammaS) were obtained by laser reflectometry. Patients were separated into groups by using the medians of S10 and gammaS. Using chi2 analyses, the distribution of the -455GG, -455GA, and -455AA genotypes in the groups with high levels of S10 (0.43, 0.49, and 0.08) and gammaS (0.45, 0.49, and 0.06) were found to be significantly distinct from those in the groups with low levels of S10 (0.67, 0.27, and 0.06; p<0.05) and gammaS (0.70, 0.23, and 0.07; p<0.01). High levels of RBC aggregation were closely associated with the rare -455A allele. Multivariate linear regression analyses showed that S10 was positively correlated with the linear combination of the fibrinogen concentration, age, and the -455G/A genotype (adjusted r = 0.63, p<0.0001). Fibrinogen and age were positive determinants, and HDL-cholesterol was a negative predictor of gammaS (adjusted r = 0.51, p<0.0001). CONCLUSION: These findings support the hypothesis that RBC hyperaggregation in premature CAD may be associated with the beta-fibrinogen -455G/A polymorphism. This association may be explained by a change in the concentration and/or the functional properties of the fibrinogen protein.

5' Untranslated Regions↗
PubMed1998

Effects of immunotherapy on experimental immunodeficiency-related lymphoproliferative disease.

BACKGROUND: Human lymphokine-activated cells (LAK cells) and interferon alpha (IFN-alpha) have been used clinically in the therapy of posttransplant lymphoproliferative disease (PTLD). However, the efficacy of such therapy has not been extensively tested under controlled experimental conditions. METHODS: A B-cell line, derived from PTLD tissue and clonally related to the parent lesion, was tested for its response to IFN-alpha in vitro. The effects of LAK cells and IFN-alpha therapy were examined in a severe combined immunodeficiency disease (SCID) mouse model in vivo. RESULTS: The PTLD cell line studied showed a 30% decrease in the rate of growth upon incubation with 500 U/ml of IFN-alpha. This in vitro response was also reproduced in vivo, in tumor therapy studies conducted in SCID mice. The magnitude of this inhibitory effect in vivo was a function of tumor burden and dose of IFN-alpha. In parallel experiments, LAK cells reduced the tumorigenicity of a lymphoblastoid cell line derived from the peripheral blood of a patient with PTLD, and prolonged the survival of SCID-beige mice with established lymphoproliferative disease. In contrast with two prior studies, in which the use of autologous cytotoxic T cells was found to be necessary, we found the administration of third-party non-HLA-matched LAK cells also to be effective in reducing tumor burden. CONCLUSIONS: These observations demonstrate the efficacy of immunotherapy for lymphoproliferative disease under controlled experimental conditions, and validate currently ongoing efforts exploring the utility of such therapy in the clinical setting.

Animals↗
PubMed1998

[Human cytomegalovirus infection and congenital malformation].

OBJECTIVE: To study the relationship between intrauterine cytomegalovirus (HCMV) infection and congenital malformation, and to determine the distribution of tissues infected. METHODS: Autopsy samples of 41 infants with congenital malformation and 19 infants with normal appearances were studied. Using polymerase chain reaction (PCR) technique the paraffin embedded specimens of main organs were examined for HCMV infection. In-situ hybridization (ISH) was performed in some of the PCR positive tissues in order to define the distribution of HCMV DNA. RESULTS: 19 of the 41 infants (46.34%) with congenital defects were HCMV positive, while 1 in 19 (5.26%) were positive in the control group, and there was significant difference between the 2 groups (P < 0.05), 20.46% (35/171) of the fetal organ samples were HCMV DNA positive in the malformation group, but only 1 out of 78 samples (1.28%%) was positive in the pulmonary tissue of the control group. More malformations of the digestive system were presented in HCMV infected babies but no statistical significant difference when compared with other systems. Brain tissue had the highest HCMV infection rates (41.37%, 12/29), which was significantly higher than other organs. By ISH technique HCMV DNA was found only in 6 out of 17 PCR positive samples, and they were located at neurons, neurogliocytes, epithelium and interstitial cells of the kidney, and epithelial cells of pulmonary alveolar. CONCLUSION: There are strong correlation between HCMV infection and congenital malformation, and brain is more susceptible to HCMV. By combining PCR and ISH, both sensitivity and distribution of HCMV could be obtained.

Abnormalities, Multiple↗
PubMed1998

A pathological study of in situ thrombosis of small pulmonary arteries and arterioles in autopsy cases of chronic cor pulmonale.

OBJECTIVE: To investigate the incidence of in situ thrombosis of small pulmonary arteries and arterioles during the exacerbation stage of chronic cor pulmonale. METHODS: 49 autopsy cases died from the exacerbation of chronic cor pulmonale were chosen as the study group, while 103 other autopsy cases without chronic cor pulmonale and disseminated intravascular coagulation (DIC) as control group. Morphologic and morphometric studies were taken on lung tissues and other organs with focus on the thrombi in small pulmonary arteries and arterioles. RESULTS: 44 cases of the study group had multiple thrombi in small pulmonary arteries and arterioles, the incidence is 89.8%, and in 9 of them, thrombi in proximal pulmonary arteries co-existed, the incidence is 18.4%. 80% of the thrombi existed in pulmonary arterioles. In the control group, only 3 cases had thrombi in small pulmonary arteries and arterioles, the incidence is 2.9%. All thrombi adhered to endangium, implying that they were in situ thrombi. No intravascular thrombosis was found in other organs. chi 2 test showed that the incidence of thrombosis and the number of thrombi in small pulmonary arteries and arterioles in cases with chronic cor pulmonale were significantly higher than those of the control group (P < 0.01). CONCLUSIONS: Multiple in situ thrombosis in small pulmonary arteries and arterioles is a prominent and common pathological change during the exacerbation stage of chronic cor pulmonale. The study suggests a new diagnostic and therapeutic concept and gives a morphological and theoretical basis for the clinical application of anticoagulants or even the thrombolytic agents for the cases of chronic cor pulmonale in the exacerbation stage.

Aged↗
PubMed1998

[Detection of telomerase activity and its clinical significance in colonic cancers by PCR-ELISA].

Using the recently developed telomerase PCR-ELISA detection kit, the authors detected the telomerase activity in 12 paired colonic cancer biopsies. It was found that strong telomerase activity was detected in all of the 12 colonic cancer tissues but not in adjacent non-cancerous tissues. These results suggest that the detection of telomerase activity by the PCR-ELISA assay could be used as a supplementary means for the diagnosis of colonic cancer.

Biopsy↗
PubMed1998

Contribution of acute-phase proteins and cardiovascular risk factors to erythrocyte aggregation in normolipidemic and hyperlipidemic individuals.

BACKGROUND: Numerous studies have demonstrated that elevated concentrations of acute-phase proteins affect red blood cell (RBC) aggregation. Plasma lipids and lipoproteins were also shown to be correlated with RBC aggregation in hypercholesterolemia. However, whether acute-phase proteins promote RBC hyperaggregation in hyperlipidemic patients is unknown. The main objective of the study was to identify the impact of acute-phase proteins such as fibrinogen (Fib), haptoglobin (Hp), ceruloplasmin (Cp), alpha1-acid glycoprotein (AGP), alpha1-antitrypsin (AT), immunoglobulin G (IgG), and albumin (Alb) on RBC aggregation in 35 hyperlipidemic patients. The influence of these proteins in 32 normolipidemic subjects was also determined. METHODS AND RESULTS: RBC aggregation parameters reflecting the kinetics of rouleau formation and the adhesive strength between RBCs were measured by laser reflectometry. Multivariate forward stepwise linear regression analyses were performed to study the relationship between RBC aggregation and these acute-phase proteins, total cholesterol (TC), triglycerides (TG), high (HDL-C) and low (LDL-C) density lipoprotein cholesterol, age, gender, body mass index (BMI), mean blood pressure (Mpresure), and smoking habit. The kinetics of rouleau formation was positively correlated with the linear combination of IgG and Hp (r=0.76, p <0.0001) in hyperlipidemic patients, whereas IgG, smoking, AGP and gender were significant independent predictors in healthy subjects (r=0.79, p <0.0001). The correlations obtained for the models predicting the adhesive strength between RBCs were 0.69 in patients (Alb, HDL-C, IgG, p <0.002) and 0.71 in healthy individuals (AGP, BMI, p <0.0001). CONCLUSION: This study suggests that acute-phase proteins such as IgG, Hp, AGP and Alb influence significantly and in an independent way the level of RBC aggregation. The close association between RBC aggregation and cardiovascular risk factors further strengthens its clinical importance.

Acute-Phase Proteins↗
PubMed1997

Differences in the erythrocyte aggregation level between veins and arteries of normolipidemic and hyperlipidemic individuals.

The objectives of this study were to detect differences in the Doppler power backscattered by blood in vivo, and to identify factors affecting the backscattered power. The main hypothesis was that variations in the erythrocyte aggregation level between veins and arteries of normolipidemic and hyperlipidemic individuals can be detected with power Doppler ultrasound. Doppler measurements were performed at 5 MHz, with an Acuson 128 XP/10 system, over the carotid artery and jugular vein, external iliac artery and vein, common femoral artery and vein and popliteal artery and vein. Doppler signals were recorded at the center of each vessel to optimize the detection of erythrocyte aggregation, and processed off-line to obtain the backscattered power. The power of each recording was compensated for Doppler gain differences, tissue attenuation with depth and transmitted power variations occurring with pulse-repetition interval modifications. Results showed statistically stronger backscattered power in veins compared to arteries for the iliac, femoral and popliteal sites. In comparison with healthy subjects, stronger powers were observed in hyperlipidemic patients for the femoral and popliteal sites. Power differences were also found between peripheral measurements. On the other hand, no difference was observed between the power measured in the carotid artery and jugular vein for both groups of individuals. Multiple linear regression analyses were performed to identify factors affecting the backscattered power. Results showed a correlation (r) of 71.2% between the Doppler power in the femoral vein and the linear combination of two parameters: an erythrocyte aggregation index S10 measured with a laser scattering method, and the diameter of the vessel measured on B-mode images. Statistically significant linear correlation levels were also found between S10 and the Doppler power in various vessels. In conclusion, this study showed that power Doppler differences exist in vivo in large vessels between veins and arteries of normolipidemic and hyperlipidemic individuals. The Doppler power variations were also shown to be related to erythrocyte aggregation.

Adult↗
PubMed1997

Three-dimensional structure of the Ras-interacting domain of RalGDS.

The Ras-interacting domains of the the protein-kinase Raf and the Ral guanine nucleotide dissociation stimulator, RalGDS, lack extensive sequence similarity, but their overall three-dimensional structures are very similar to each other. Mutational analysis indicated that three residues in the RalGDS domain are critical for its interaction with Ras.

Amino Acid Sequence↗
PubMed1997

Cloning and characterization of an uncoupling protein homolog: a potential molecular mediator of human thermogenesis.

We have identified a novel cDNA encoding a protein highly homologous to the mammalian brown fat uncoupling protein (UCP). Unlike the known UCP, which is expressed specifically in brown adipose tissue, the UCP homolog (UCPH) mRNA is expressed in a variety of tissues, with predominant expression in human white adipose tissue and skeletal muscle. In the white adipose tissue of ob/ob and db/db mice, the UCPH transcript is induced approximately fivefold relative to lean littermate controls. Expression of murine UCPH in yeast results in growth inhibition under conditions that require aerobic respiration, but does not affect growth under anaerobic conditions. Furthermore, UCPH expression in yeast causes a decrease in the mitochondrial membrane potential, as judged by staining with the potential-sensitive dye DiOC6. These observations suggest that UCPH, like UCP, uncouples oxidative phosphorylation. The possibility that the UCPH protein is an important mediator of human thermogenesis is discussed.

Amino Acid Sequence↗
PubMed1997

[Status and attitude to smoking in 1,214 nurses in Beijing].

Smoking in medical professionals is increasingly attracted attention to. A lot of studies on smoking in physicians at home have been reported, but few in nurses. In order to understand current status of smoking and trend of its changes in nurses, 1,214 female nurses in five hospitals of Beijing were interviewed on their smoking in 1993. Results showed an average proportion of smoking of 7.4%, 7.3% in urban and 7.9% in rural hospitals. As compared with the results of a survey conducted five years ago (with an average proportion of smoking of 1.6%), proportion of smoking in nurses increased obviously. Proportion of smoking quitting was very low (3.3%) in nurses, although most of them could recognize harmfulness of smoking and publicize it to patients.

Adult↗
PubMed1996

Pw1, a novel zinc finger gene implicated in the myogenic and neuronal lineages.

The cellular and molecular processes leading to the establishment of the skeletal muscle lineage in the vertebrate are not well understood. The MyoD-related family of myogenic regulatory factors (MRFs) are expressed during somitogenesis although cells with myogenic capacity are present prior to gastrulation. We propose that regulatory genes exist that guide the skeletal muscle lineage during early development. In an effort to identify these regulatory genes, we performed a differential screening to isolate transcripts that are present in myogenic cells and in the embryo prior to MRF expression but absent in nonmyogenic fibroblasts. We report here the identification of Pw1. The Pw1 transcript is approximately 8.5 kb long and encodes a large protein containing 12 widespread C2H2 zinc fingers and 3 motifs containing periodic prolines and acidic residues. Consistent with the possibility that Pw1 is a transcription factor, we observe nuclear localization of the protein. Pw1 is strongly expressed upon gastrulation and subsequently becomes restricted to skeletal muscle and subregions of the central nervous system. Pw1 is initially expressed in all mesodermal cells early in development; however, its maintained expression in adult differentiated muscle suggests a specific role in the skeletal muscle lineage. Pw1 expression is cell cycle specific with levels highest during late M-phase. The gene is intronless which may facilitate transcription during cell division. At present, the precise function of Pw1 is not understood; however, we note that Pw1 maps to the proximal region of chromosome 7 near the axial segmentation mutant pudgy which shows severe perturbation of axial skeletal and muscle structures.

Animals↗
PubMed1996

Evidence that the diabetes gene encodes the leptin receptor: identification of a mutation in the leptin receptor gene in db/db mice.

OB-R is a high affinity receptor for leptin, an important circulating signal for the regulation of body weight. We identified an alternatively spliced transcript that encodes a form of mouse OB-R with a long intracellular domain. db/db mice also produce this alternatively spliced transcript, but with a 106 nt insertion that prematurely terminates the intracellular domain. We further identified G --> T point mutation in the genomic OB-R sequence in db/db mice. This mutation generates a donor splice site that converts the 106 nt region to a novel exon retained in the OB-R transcript. We predict that the long intracellular domain form of OB-R is crucial for initiating intracellular signal transduction, and as a corollary, the inability to produce this form of OB-R leads to the severe obese phenotype found in db/db mice.

Alternative Splicing↗
PubMed1996

Influence of acute-phase proteins on erythrocyte aggregation.

With the exception of fibrinogen, immunoglobulins, and albumin, little information is available on the effect of acute-phase proteins on erythrocyte aggregation. The objective of this study was to investigate the effects of haptoglobin (Hp), C-reactive protein (CRP), ceruloplasmin (Cp), alpha 1-acid glycoprotein (alpha 1-AGP), and alpha 1-antitrypsin (alpha 1-AT) on the aggregation kinetics and shear resistance of erythrocyte aggregates. The plasma concentration of these proteins was measured in 20 healthy individuals and kept unchanged while the concentration of the protein tested was increased. Adding Hp to concentrations between 2.78 and 4.99 g/l resulted in a significant progressive increase in aggregation kinetics compared with controls. An elevation of the shear resistance of the aggregates was found for CRP at a concentration of 0.438 g/l. By an increase in the concentration of Cp from 4.40 to 9.39 g/l, the aggregation kinetics and the adhesive forces between erythrocytes were significantly increased: No effect on erythrocyte aggregation was observed for alpha 1-AGP, alpha 1-AT, and Cp at concentrations of 2.85, 3.97, and 2.43 g/l, respectively. The molecular mass of the acute-phase proteins, their configuration, and the presence of specific receptors on the erythrocyte membrane are postulated as possible factors influencing erythrocyte aggregation.

Acute-Phase Proteins↗
PubMed1996

[The pulmonary function in scoliotic patient].

This paper investigated preoperative pulmonary functions in 134 scoliotic patients, of whom 32 cases was followed up for their postoperative pulmonary functions. The results show that the bigger the Cobb of the scoliosis, the greater the damages of the pulmonary functions. Congenital scoliosis is more severely affected by pulmonary functions than idiopathic scoliosis. There was no significant difference among the different sections of scoliosis with regard to their effect on the pulmonary functions. The authors concluded that the Harrington Instrumentation improved pulmonary functions in scoliosis.

Adolescent↗