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Biomedical subjects

F Wang

Publications and source records attributed to F Wang.

At least 487 records · Page 27Linked to original sources
PubMed1996

Comparative analysis identifies conserved tumor necrosis factor receptor-associated factor 3 binding sites in the human and simian Epstein-Barr virus oncogene LMP1.

Nonhuman primates are naturally infected with a B-lymphotropic herpesvirus closely related to Epstein-Barr virus (EBV). These simian EBV share considerable genetic, biologic, and epidemiologic features with human EBV, including virus-induced tumorigenesis. However, latent, transformation-associated viral genes demonstrate marked sequence divergence among species despite the conserved functions. We have cloned the latent membrane protein 1 (LMP1) homologs from the simian EBV naturally infecting baboons (cercopithicine herpesvirus 12, herpesvirus papio) and rhesus monkeys (cercopithicine herpesvirus 15) for a comparative study with the human EBV oncogene. The transmembrane domains are well conserved, but there is striking sequence divergence of the carboxy-terminal cytoplasmic domain essential for B-cell immortalization and interaction with the tumor necrosis factor receptor signaling pathway. Nevertheless, the simian EBV LMP1s retain most functions in common with EBV LMP1, including the ability to induce NF-(kappa)B activity in human cells, to bind the tumor necrosis factor-associated factor 3 (TRAF3) in vitro, and to induce expression of tumor necrosis factor-responsive genes, such as ICAM1, in human B lymphocytes. Multiple TRAF3 binding sites containing a PXQXT/S core sequence can be identified in the simian EBV LMP1s by an in vitro binding assay. A PXQXT/S-containing sequence is also present in the cytoplasmic domain of the Hodgkin's disease marker, CD30, and binds TRAF3 in vitro. The last 13 amino acids containing a PXQXT/S sequence are highly conserved in human and simian EBV LMP1 but do not bind TRAF3, suggesting a distinct role for this conserved region of LMP1. The conserved TRAF3 binding sites in LMP1 and the CD30 Hodgkin's disease marker provides further evidence that a TRAF3-mediated signal transduction pathway may be important in malignant transformation.

Amino Acid Sequence↗
PubMed1996

Blindness due to cataract: epidemiology and prevention.

Cataract is the leading cause of blindness, accounting for 50% of blindness worldwide. Although significant progress has been made toward identifying risk factors for cataract, there is no proven primary prevention or medical treatment. Surgical removal of cataract remains the only therapy. In this paper, we reviewed (a) the prevalence and incidence data of cataract, (b) the findings on risk factors for cataract, and (c) health service utilization and outcome of cataract surgery in both developed and developing countries.

Adult↗
PubMed1996

Role of estrogen receptor/Sp1 complexes in estrogen-induced heat shock protein 27 gene expression.

Treatment of MCF-7 human breast cancer cells with 10 nM 17 beta-estradiol (E2) resulted in a 2-fold induction of heat shock protein (Hsp) 27 mRNA levels, and this response persisted for up to 24 h. The 5'-promoter region of the gene was further investigated to identify genomic sequences associated with E2 responsiveness. An Sp1 and half-palindromic estrogen response element (ERE) separated by 10 nucleotides, GGGCGGG(N)10GGTCA, were identified at -105 to -84, and formation of the Sp1/estrogen receptor (ER) complex was investigated by in vitro assays using synthetic Hsp 27-[32P]Sp1/ERE oligonucleotides in a gel mobility shift assay and transient transfection studies using short (-108/-84) and long (-108/+23) 5'-promoter sequences linked to a thymidine kinase promoter and the bacterial chloramphenicol acetyl transferase (CAT) reporter gene (Hsp-CATs and Hsp-CATl, respectively). Incubation of nuclear extracts from MCF-7 cells with an Hsp 27-[32P]Sp1/ERE oligonucleotide results in formation of an Sp1/ER complex. The formation of this complex was inhibited by coincubation with unlabeled Sp1/ERE, ERE, and Sp1 oligonucleotides and by preincubation with ER or Sp1 antibodies (immunodepletion). In addition, the complex was supershifted by coincubation with ER antibodies. Mutation of either Sp1 or ERE sites also decreases formation of the retarded band. E2 induced CAT activity in MCF-7 cells transiently transfected with either Hsp-CATs or Hsp-CATl plasmids. It was also demonstrated that E2 did not significantly induce CAT activity in MCF-7 cells transiently transfected with Hsp-CATl-containing mutations in both the Sp1 and ERE sites. The results of this study demonstrate that an Sp1/ER complex is involved in E2-induced Hsp 27 gene expression.

Antibodies↗
PubMed1996

Presence of human polyomavirus DNA in the peripheral circulation of bone marrow transplant patients with and without hemorrhagic cystitis.

In BMT patients, shedding of BK virus (BKV) in the urine has been strongly but not absolutely correlated to hemorrhagic cystitis (HC). The possible presence of human polyomaviruses in peripheral blood leukocytes (PBLs), plasma, serum and urine in BMT patients and an association with HC was investigated by a nested PCR assay. Samples from allogeneic BMT patients with and without HC as well as from autologous BMT patients were analyzed. Human polyomaviruses were detected in urine and blood samples of both allogeneic and autologous BMT patients with and without HC. An association between the presence of a specific human polyomavirus in blood and HC was thus not observed.

Adolescent↗
PubMed1996

Cordocentesis: a useful method for prenatal diagnosis.

OBJECTIVE: To evaluate the efficacy and safety of cordocentesis for prenatal diagnosis of various fetal diseases. PATIENTS AND METHODS: Fetal blood sampling was performed in 30 pregnancies from gestational week 19 to 36 for various prenatal diagnoses. We used Aloka SSD-650 real-time ultrasound scanner with 3.5 mHz curvilinear transducer during the procedure. A regular 22-gauge spinal needle was used for fetal blood sampling. RESULTS: Twenty-five cordocentesis were successful at the first attempt. A second attempt of cordocentesis succeeded in three cases. In the remaining two cases, intrahepatic vein sampling and cardiocentesis were employed respectively. The duration of procedure was shorter than 15 minutes in 25 cases. 1-6 ml of fetal blood was obtained from each case. Fetal blood was diluted with amniotic fluid in four samples. Maternal blood contamination never happened. No lethal complication occurred in our series. CONCLUSION: It is believed that cordocentesis is a safe and useful method for prenatal diagnosis, and intrahepatic vein sampling is an alternative choice when cordocentesis has failed.

Cordocentesis↗
PubMed1996

[An experimental study on effects of form deprivation on development of myopia].

OBJECTIVE: The study was designed to approach the pathogenesis of myopia. METHOD: Haisaik chickens were used to establish the animal models of myopia and form deprivation method was applied. Monocular eyelids were sutured for form deprivation on the 5th day after chicken birth. RESULTS: Form deprivation leads to myopic refractive abnormality (P < 0.001). The ocular anteroposterior axis (P < 0.005), transverse and vertical diameters lengthen (P < 0.05). In the mean time, obvious pathologic changes were found. The cartilaginous cell layer of the sclera became thicker, the numbers of chondrocytes and binucleate cells were greater, and the fibrous layer of the sclera was thinner. CONCLUSION: Form deprivation is the main cause of the development of myopia.

Animals↗
PubMed1996

No differences in mucosal adaptive growth one week after intestinal resection in rats given enteral glutamine supplementation or deprived of glutamine.

OBJECTIVE: To evaluate the effects of intraluminal glutamine on the adaptation of intestinal mucosa after resection compared with transsection and un-operated on control animals. DESIGN: Open, controlled, experimental study. SETTING: University hospital, Sweden. SUBJECTS: 123 Sprague-Dawley rats. INTERVENTION: Daily isonitrogenous oral diet was given either free of glutamine or supplemented with 4% glutamine for 2 or 7 days to rats subjected to intestinal resection, transection or no operation. MAIN OUTCOME MEASURES: Body weight and protein content, DNA content, and thymidine incorporation in jejunal and ileal mucosa. RESULTS: Resection resulted in a significant growth stimulation evaluated by weight/body weight, protein, and DNA content (p < 0.05-0.001). Glutamine supplementation did not significantly influence this growth response. Thymidine incorporation in jejunum was stimulated by glutamine on day 3 (p < 0.05-0.001). CONCLUSION: The glutamine fortified diet had no growth stimulating effects compared with a glutamine free diet one week after 60% intestinal resection. An early increase in thymidine incorporation indicated that glutamine had a transient proliferative effect.

Adaptation, Physiological↗
PubMed1996

[The first exploration of the properties and laws of mutation plastids transmitting with cell division].

Suppose there are m plastids in an initial cell, in which i plastids are mutated. In the this paper we discuss the probability that m mutated plastids are distributed in a cell simultaneously during in the process of mutant plastids dividing and randomly distributing with cell division. Let x(t) = 1 denote the stochastic event that a cell contains only mutant plastids in t-th division and x(t) = 0 denote the opposite event. We may find some properties of the stochastic process ¿x(t), t epsilon T¿ demonstrating that the process is a Markov chain. Finally we can obtain the matrixes of transition probability between homogeneous heterogeneous plastids, this reveals some laws of mutant plastids transmitting with cell division.

Cell Division↗
PubMed1996

Effect of repetitive bleeding on NADH-cytochrome b5 methemoglobin reductase activity and molybdenum content in erythrocytes in rats.

Reticulocytosis in rats was induced by repetitive bleeding. Both in the vitro and the in vivo studies showed that the detected reductive speed of methemoglobin of the bleeding group was faster than that of the control group at all time intervals. At the same time, the NADH-cytochrome b5 methemoglobin reductase activity and the molybdenum content in erythrocytes of the bleeding group were significantly increased. Regressional analysis showed that there was a significantly positive correlation between the enzyme activity and the molybdenum content. It is proposed that molybdenum might be required for the enzyme activity.

Animals↗
PubMed1996

Exercise hemodynamic benefits of rate adaptive ventricular pacing.

OBJECTIVE: To investigate the exercise hemodynamic benefits of activity-sensing rate adaptive ventricular pacing (VVIR) over fixed rate pacing (VVI) mode. METHODS: Activity sensing rate adaptive pacemaker was implanted in 19 patients (13 males and 6 females, mean age 54.8 years) with bradycardia. All patients underwent symptom-limited upright bicycle exercise in VVIR and VVI pacing modes in random order after implantation. With electrocardiogram monitor and M-mode echocardiography, heart rate, stroke volume and cardiac output were measured at rest and at each stage of exercise. RESULTS: All patients were pacemaker dependent, without any spontaneous heart rhythm throughout this study. In the activity sensing ventricular pacing mode, all patients achieved a significant increase in exercise duration compared to fixed rate ventricular pacing mode (mean +/- s, 437 +/- 45 vs 323 +/- 23sec; P < 0.01), with a mean maximum pacing rate of 113 +/- 23ppm. Although the cardiac output was significantly improved in both pacing modes (10.2 +/- 1.4L/min with VVIR and 7.5 +/- 1.1L/min with VVI), the maximum exercise cardiac output in VVIR was increased over VVI by 46% (P < 0.05). Additionally, the stroke volume was significantly increased by 50% or more at rest in VVI mode, but was relatively maintained in VVIR mode (P > 0.05). CONCLUSION: Rate adaptive ventricular pacing can significantly improve the exercise capacity and cardiac output in patients with bradycardia. The increment of exercise cardiac output in VVIR mode is mainly dependent upon the pacing rate during exercise.

Cardiac Output↗
PubMed1996

[Cordocentesis for prenatal diagnosis of fetal diseases].

For the purpose of prenatal diagnosis, 30 fetal blood samplings were performed in 30 pregnant women from 19 to 36 gestational weeks. The samples were taken with a 22-gauge needle guided by ultrasound. Twenty-five cordocenteses were succeeded at the first attempt. A second attempt was needed in other 5 cases. The duration of procedure was less than 15 minutes in 83.3% cases. 1-6 ml fetal blood was obtained for each case. No lethal complication occured in our series. It is believed that cordocentesis could be a useful tool for prenatal diagnosis, and the intrahepatic-vein sampling is a preferable alternative choice if cordocentesis fails.

Cordocentesis↗
PubMed1996

The use and costs of physician services for ophthalmic surgical procedures in 1988 and 1991.

BACKGROUND AND OBJECTIVE: To examine the change in volume and costs of physician services for ophthalmic surgical procedures associated with physician fee cuts. MATERIALS AND METHODS: The authors analyzed the physician claims (Part B) data for a 5% random sample of the Medicare population. Number, rate, average allowed charge, and total cost of physician services for ophthalmic surgical procedures were compared for 1988 and 1991. RESULTS: An estimated 3.1 million (98 per 1000) ophthalmic surgical procedures were performed on Medicare beneficiaries in 1991, compared with 2.3 million (76 per 1000) in 1988. There was a 35% increase in number and a 28% increase in rate. The average allowed charge for these services decreased by 26% ($1155 vs $852 per procedure), with an overall cost of $2.6 billion in both years. CONCLUSION: A reduction in fee for physician services for ophthalmic surgical procedures from 1988 to 1991 was associated with an increase in the volume of the services. The overall costs of physician services for ophthalmic surgical procedures remained consistent between the two years.

Direct Service Costs↗
PubMed1996

Rat as an animal model carrying human hepatitis B virus in hepatocytes.

OBJECTIVE: To establish an experimental animal model of rat carrying human hepatitis B virus in the hepatocytes using a simple and reproducible method. MATERIALS AND METHODS: Human serum rich in hepatitis B virus was injected into portal veins and caudalis veins of young male Wistar rats. One and two months after the injection, liver biopsies were done. In situ hybridization and immunohistochemical study of liver specimens were carried out. Sera were also examined for HBV DNA by polymerase chain reaction. RESULTS: All of seven rats in this experiment were HBV DNA and HBV surface antigen (HBsAg) positive in their hepatocytes. Most HBV positive hepatocytes were distributed around the central vein and scattered in the liver lobules, and HBV DNA and HBsAg were located in cytoplasm. HBsAg exists mainly as the forms of diffuses and inclusion body. No hepatocytic damage or inflammation was observed. Neither viremia nor antigenemia was detected. CONCLUSIONS: Our studies showed for the first time that natural human HBV can enter Wistar rat liver cells through intravenous injection efficiently and express for a long period. This animal model can be used in the studies of HBV molecular biology, therapeutic regimens and prophylaxis against HBV. A possible mechanism of HBV entering rat hepatocytes is also proposed.

Animals↗
PubMed1996

[The protective effects of dichloroacetate on cerebral ischemia after reperfusion of fed rats].

OBJECTIVE: To study the brain protective mechanisms of dichloroacetate (DCA) by observing the influence of DCA on the biochemical and pathological changes in ischemic brain tissues in different periods of reperfusion. METHODS: The FED-RAT cerebral ischemic model induced by 4-vessel occlusion was applied. 55 mature male Sprague-Dawley rats were divided into the control group, normal saline and DCA-treated groups before ischemia, normal saline and DCA-treated groups after ischemia equally and randomly. RESULTS: DCA could significantly lower the brain lactic acid, water content, and the diameter of cortical neurons, and protect the pathological damage of the membranaceous structure, before or after ischemia at a dose of 25 mg/kg, compared with the normal saline treated groups. CONCLUSION: Lowering brain lactate, resisting brain edema and protecting the membranaceous structures are the main brain protective mechanisms of DCA in biochemistry and ultrastructure.

Animals↗