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Biomedical subjects

G Wu

Publications and source records attributed to G Wu.

At least 667 records · Page 37Linked to original sources
PubMedDate not supplied

Inhibition of neurite outgrowth of neuroblastoma Neuro-2a cells by cholera toxin B-subunit and anti-GM1 antibody.

The role of cell surface GM1 ganglioside in neurite outgrowth of Neuro-2a neuroblastoma cells was investigated by application of anti-GM1 antibody and the B subunit of cholera toxin (cholera B) to cultured cells stimulated to grow neurites in various ways. When the cells were simultaneously treated with stimulatory agent and cholera B, inhibition, as measured by percent of neurite-bearing cells, was observed with most stimuli: neuraminidase; GD1a ganglioside, retinoic acid, and low serum. However, with dibutyryl cyclic AMP the small reduction observed was not statistically significant. The inhibitory effect of cholera B on neurite outgrowth induced by low serum was dose-dependent, reaching a maximum at 200 ng/mL; 48 h after washout of cholera B the cells were released from inhibition and regrew neurites at nearly the previous rate in the presence of low serum. When the cells were exposed to stimulus for 6 h or more the inhibitory effect of subsequent addition of cholera B was reduced or eliminated; inhibition thus occurs during an early stage of neurite initiation. Anti-GM1 antibody at dilutions of 1:100-1:400 had the same inhibitory effect as cholera B with cells stimulated by GD1a or retinoic acid, whereas anti-GM2 antibody had no effect at 1:200 or 1:400; inhibition by the latter antibody at 1:100 dilution was similar to that attained with control ascites fluid. These results point to a pivotal role for cell surface GM1 in Neuro-2a differentiation induced by many (but not all) neuritogenic agents.

Animals↗
PubMedDate not supplied

Update on continuous ambulatory peritoneal dialysis.

By now many patients have been successfully maintained on CAPD for five years or more, thus demonstrating that CAPD is a viable long-term treatment for end-stage renal disease. Peritonitis--the main concern of the earlier years--is now a less frightening complication. We know better how to treat peritonitis and its incidence has decreased from one episode every 8 months initially to one episode every 18 months now. In addition, several innovations, which have been or soon will be introduced, promise to decrease the frequency of peritonitis to an even lower rate. The problem of peritonitis is now being replaced by the chronic complications of CAPD, predominantly malnutrition and decrease in peritoneal ultrafiltration. CAPD has become an important adjunct in the treatment of children with ESRD, especially the very young. Even though not normal, their growth on CAPD is better than that of children on hemodialysis and as good as that after a successful transplant. CAPD has become a promising treatment for the diabetic with ESRD. This experience has stimulated interest and research in the role of intraperitoneal administration of insulin for blood glucose control. With the present worldwide experience of CAPD, this treatment has ceased to be experimental. A percentage of patients requiring dialysis will be better off on CAPD than on hemodialysis. Even though this percentage will vary among various countries, the nephrologist who wants to provide the best treatment for each patient must be well experienced in and have all treatments at his disposal including CAPD.

Adult↗
PubMedDate not supplied

Ethanol inhalation on 1-[14C]-pyruvate kinetics in mice using a six-compartment closed model.

1-[14C]-pyruvate kinetics were studied in mice with and without inhalation of vaporised ethanol. The 1-[14C]-pyruvate kinetics were modelled by a six-compartment closed model, i.e. injected site, blood, periphery, expired 14CO2 in air, eliminated 14C in urine and faeces, using the system of differential equations. The results show that the inhalation of vaporised ethanol can stimulate expiration of 14CO2. The completely analytical solution of the six-compartment closed model was found using Laplace transform. The kinetic parameters were estimated using the analytical solutions for the fourth, fifth and sixth compartments to fit eliminated 14CO2, and 14C in urine and faeces. The compartmental analysis showed that the inhalation of vaporised ethanol can stimulate 1-[14C]-pyruvate transmembrane process from injected site to blood and 14C trans-tissue process from periphery to blood.

Administration, Inhalation↗
PubMedDate not supplied

Sensitivity analysis of pharmacodynamic parameters in pharmacodynamic models.

The quantitative properties of a pharmacodynamic model can be characterized by the pharmacodynamic parameters. The sensitivity analysis of pharmacodynamic parameters in eight kinds of pharmacodynamic models was conducted. The sensitivity functions with respect to different pharmacodynamic parameters for these pharmacodynamic models were deduced using the partial derivative. The pharmacodynamic parameters were ranked according to their sensitivity functions.

Algorithms↗
PubMedDate not supplied

Morbidity due to schistosomiasis japonica in the People's Republic of China.

Transmission and morbidity induced by Schistosoma japonicum were evaluated in 825 individuals undergoing periodic treatment with praziquantel on Jishan island, Jiangxi Providence, in the People's Republic of China. Eggs of S. japonicum were found in the stools of 39.4% of the population; 70% of those infected were less than 20 years of age. Hepatomegaly greater than 3 cm in the midsternal line was detected by physical examination and ultrasonography in 75% and 90% of individuals, respectively, regardless of infection status. Symmer's clay pipe-stem fibrosis of the liver was detected by ultrasonography in 20% of all individuals. Hepatitis B surface antigen and antibody to hepatitis C were found in 11% and less than 1% of the population, respectively. Our study suggests that, despite intermittent chemotherapy, morbidity due to S. japonicum is still a significant problem in China.

Adolescent↗
PubMedDate not supplied

Schistosomiasis japonica on Jishan Island, Jiangxi Province, People's Republic of China: persistence of hepatic fibrosis after reduction of the prevalence of infection with age.

Hepatic fibrosis due to schistosomiasis japonica was examined by ultrasonography in a cross-sectional community study of 825 individuals on Jishan Island, Jiangxi Province, China. The prevalence of active infection was 39.4% with peak infection in the 10-19.9 years age group followed by a significant decline. A similar pattern was observed for intensity of infection. The prevalence of hepatomegaly in the midsternal line > or = 6 cm peaked at 60% in the fourth decade and remained elevated. A progressive increase in the severity of hepatic periportal fibrosis was observed with age, with advanced fibrosis peaking in the fifth decade. The proportion of individuals with advanced fibrosis was significantly greater in males than in females despite equivalent prevalence and intensity of schistosome infection. In addition, a positive association (P < 0.01) was found between periportal fibrosis and both hepatomegaly > or = 6 cm and splenomegaly. This study suggests that the natural history of schistosomiasis japonica in this hyperendemic community in China is marked by persistence of hepatomegaly and schistosome-induced periportal fibrosis in adults despite a decrease in the prevalence of infection.

Adolescent↗
PubMedDate not supplied

Competition of viral and satellite RNAs of cucumber mosaic virus for replication in vitro by viral RNA-dependent RNA polymerase.

Cucumber mosaic virus (CMV) satellite RNA-induced viral symptom modulation is usually accompanied by a significant reduction of virus accumulation in plant tissue, which has led to the hypothesis that satellite RNA competes with the viral RNAs for replication by the viral replicase and thereby reduces viral RNA synthesis and viral symptoms. In this report, the RNA synthesis of the viral and satellite RNAs of CMV was studied in vitro using an RNA-dependent RNA polymerase (RdRp) purified from CMV-infected plants. Comparison of the kinetics of the CMV RdRp-catalysed RNA synthesis using as templates viral RNAs and satellite RNA, alone or in an appropriate mixture, showed that these RNAs competed with each other for RNA synthesis by the CMV RdRp. Determination of the rates of 32P incorporation into the viral and satellite double-stranded RNA products revealed an apparent replication advantage of the satellite RNA over viral RNAs. The results provide strong support for a previously proposed biochemical mechanism that attributes CMV satellite-induced viral symptom modulation to the replication competition between the satellite and viral RNAs.

Cucumovirus↗
PubMedDate not supplied

Discrimination of transport systems for methylmercury-cysteine uptake in rat erythrocytes by inhibitors and other factors.

The transport systems for methylmercury-cysteine (MeHgCys) uptake by isolated erythrocytes from rats were studied at 5 degrees C. Probenecid was used to test the organic acid transport system at different concentrations. While inhibiting the organic acid transport system by probenecid (0.25 mM), the following agents were used to determine other transport systems for MeHgCys uptake: (1) ouabain and sodium fluoride (NaF) were used to test the active transport system; (2) 4,4'-diisothiocyano-2,2'-stilbenendisulphonic acid (DIDS) and N-ethylmaleimide (NEM) were used to test the C1-ion transort system; (3) colchicine and vinblastine were used t o test the microtubule system; (4) hexanol was used to test the protein-mediated trasport systems and the non-electrolyte diffusion; (5) valinomycin was used to test the effect of the membrane potential on MeHgCys uptake. Furthermore, the effects of NH4+, Li+ and Na+ in the buffer on MeHgCys uptake were examined with or without probenecid. The results showed that most of MeHgCys was transported by the organic acid transport system. Colchicine and vinblastine stimulated MeHgCys uptake. NH4+, Li+ and Na+ ions could stimulate MeHgCys uptake with or without probenecid. Meanwhile, a small amount of MeHgCys was transported by means of the non-electrolyte diffusion which was stimulated by hexanol. Furthermore, DIDS could stimulate MeHgCys uptake and the transport systems for MeHgCys uptake were sensitive to the membrane potential.

Animals↗
PubMedDate not supplied

Hyperacute rejection is attenuated in GalT knockout swine lungs perfused ex vivo with human blood.

BACKGROUND: Hyperacute rejection (HAR) is one of the principal obstacles to successful xenotransplantation. Homozygous alpha-1,3-galactosyltransferase knockout (GalT-KO) miniature swine now offer the prospect of overcoming this barrier to xenotransplantation. In this study, the short-term function of GalT-KO swine lungs was evaluated in a well-established ex vivo model of swine-to-human lung xenotransplantation. METHODS: Lungs from homozygous GalT-KO swine (n = 3) and control lungs from pigs of the background strain used to create the GalT-KO pig line (n = 2) were perfused ex vivo with freshly collected heparinized human blood. Graft function was assessed by various physiologic measurements, serial histologic and immunohistochemical evaluation, and assays of complement and platelet activation. RESULTS: Xenoperfused control swine lungs exhibited HAR with graft survival times <5 minutes. In contrast, GalT-KO swine lungs retained their function for approximately 2 hours, on average. GalT-KO swine lungs showed decreased complement and platelet activation compared with controls. Nonetheless, activation of complement and coagulation cascades was not completely eliminated in the GalT-KO swine lungs. CONCLUSIONS: The survival of xenoperfused GalT-KO swine lungs was significantly prolonged, as compared with control lungs expressing Gal. This appears to have been due largely to substantially reduced complement activation. Nonetheless, the xenoperfused GalT-KO lungs still showed some evidence of complement fixation and intravascular coagulopathy by the time of graft demise.

Acute Disease↗
PubMedDate not supplied

Association between IgE antibody against soluble egg antigen and resistance to reinfection with Schistosoma japonicum.

There is evidence that immunoglobulin (Ig) E antibody may be a critical component of protective immunity against Schistosoma mansoni and S. haematobium reinfection. In the present study, 555 individuals aged 3-67 years infected with S.japonicum received praziquantel treatment before the transmission season commenced; 45 d later, blood samples from 265 individuals who had no S. japonicum egg in their stool were examined by enzyme-linked immunosorbent assay for specific isotypic antibodies. Single, non-conditional logistic regression analysis showed that exposure intensity, age, soluble egg antigen (SEA)-IgE, SEA-IgM and soluble adult worm antigen-IgG4 were relevant to reinfection; multiple, non-conditional logistic regression analysis showed that exposure intensity was still a significant factor for reinfection while the SEA-IgE antibody level was associated with resistance to reinfection with S. japonicum, with a protective index of 2.00. It is suggested that this population in an area endemic for schistosomiasis japonica exhibits acquired immunity.

Adolescent↗
PubMedDate not supplied

Polymeric gadolinium chelate magnetic resonance imaging contrast agents: design, synthesis, and properties.

We have synthesized and evaluated five series of polymeric gadolinium chelates which are of interest as potential MRI blood pool contrast agents. The polymers were designed so that important physical properties including molecular weight, relaxivity, metal content, viscosity, and chelate stability could be varied. We have shown that, by selecting polymers of the appropriate MW, extended blood pool retention can be achieved. In addition, relaxivity can be manipulated by changing the polymer rigidity, metal content affected by monomer selection, viscosity by polymer shape, and chelate stability by chelator selection.

Animals↗
PubMedDate not supplied

Structural basis of IAP recognition by Smac/DIABLO.

Apoptosis is an essential process in the development and homeostasis of all metazoans. The inhibitor-of-apoptosis (IAP) proteins suppress cell death by inhibiting the activity of caspases; this inhibition is performed by the zinc-binding BIR domains of the IAP proteins. The mitochondrial protein Smac/DIABLO promotes apoptosis by eliminating the inhibitory effect of IAPs through physical interactions. Amino-terminal sequences in Smac/DIABLO are required for this function, as mutation of the very first amino acid leads to loss of interaction with IAPs and concomitant loss of Smac/DIABLO function. Here we report the high-resolution crystal structure of Smac/DIABLO complexed with the third BIR domain (BIR3) of XIAP. Our results show that the N-terminal four residues (Ala-Val-Pro-Ile) in Smac/DIABLO recognize a surface groove on BIR3, with the first residue Ala binding a hydrophobic pocket and making five hydrogen bonds to neighbouring residues on BIR3. These observations provide a structural explanation for the roles of the Smac N terminus as well as the conserved N-terminal sequences in the Drosophila proteins Hid/Grim/Reaper. In conjunction with other observations, our results reveal how Smac may relieve IAP inhibition of caspase-9 activity. In addition to explaining a number of biological observations, our structural analysis identifies potential targets for drug screening.

Animals↗
PubMedDate not supplied

Application of queueing theory with Monte Carlo simulation to the study of the intake and adverse effects of ethanol.

A deterministic approach has so far been used in the modelling of the intake, metabolism, and elimination of ethanol. However, a well-structured deterministic model needs to consider numerous factors, e.g. anatomical structure, metabolic rate, perfusion rates, non-steady-state and steady-state. In the present study, a stochastic approach was used for modelling the study of ethanol because there is a phenomenological analogy between a queueing system and the systems in the body dealing with ethanol. When using queueing theory, both the consumption of ethanol and the removal of the adverse effects associated with its consumption from the body can be random processes; and the requirement for detailed information on the anatomical structure etc. can be minimized. Using queueing theory, estimations can be made with regard to the accumulated adverse effects of ethanol in the body, the time needed to remove the adverse effects etc. Monte Carlo simulation was performed to analyse the drinking of beer and the removal of the adverse effects associated with it, and to show the potential use of queueing theory in the study of ethanol.

Alcohol Drinking↗
PubMedDate not supplied

Frequency and Markov chain analysis of the amino-acid sequence of human alcohol dehydrogenase alpha-chain.

The amino-acid sequences of human alcohol dehydrogenase alpha-chain (ADH1) were analysed according to two-, three- and four-amino-acid sequences. The measured frequencies and probabilities were compared with the predicted frequencies and probabilities. Of 373 two-amino-acid sequences in the ADH1, 92 (24.665%) and 32 (8.579%) sequences can be explained by the predicted frequencies and probabilities according to a purely random mechanism. Of 191 non-appearing two-amino-acid sequences in the ADH1, 119 (62.304%) and 52 (27.225%) sequences can be explained by the predicted frequencies and probabilities according to a purely random mechanism. Of 373 measured first-order Markov transition probabilities for the second amino acid in two-amino-acid sequences, three (0.804%) probabilities match the predicted conditional probabilities and therefore can be explained by a purely random mechanism. No more-than-two-amino-acid sequences can be explained by a purely random mechanism.

Alcohol Dehydrogenase↗
PubMedDate not supplied

Use of a five-compartment closed model to describe the effects of ethanol inhalation on the transport and elimination of injected pyruvate in the rat.

A five-compartment closed model was established using the system of differential equations. The completely analytical solution of a five-compartment closed model was found using the Laplace transform. 2-[14C]Pyruvate kinetics were studied in rats without and with inhalation of vaporized ethanol, and were modelled by the five-compartment closed model, i.e. injected site, blood, eliminated 14CO2 in air, eliminated 14C in urine and faeces. The kinetic parameters were estimated using the analytical solution of the five-compartment closed model to fit eliminated 14CO2, and 14C in urine and faeces simultaneously. The compartmental analysis showed that the inhalation of vaporized ethanol can increase 2-[14C]pyruvate trans-membrane, trans-tissue processes and oxidation rate. The model developed is useful for general pharmacokinetic and toxicokinetic analysis as well as for studies on ethanol.

Administration, Inhalation↗
PubMedDate not supplied

Molecular cloning of G1 phase mRNAs from a subtractive G1 phase cDNA library.

Many G1-phase-specific mRNAs have been identified from various normal or transformed cells based on serum induction and re-entry into the cell cycle from quiescence. However, these mRNAs may not represent some important genes expressed during G1 phase in continuously cycling cells. The eukaryotic cell cycle possesses two cdk (cyclin-dependent kinase) dependent regulatory gates through which cells pass during late G1 phase and G2 phase of each cycle. Subtractive hybridization was employed to synthesize a high R0t fraction cDNA library enriched in sequences expressed during G1 phase prior to passage through the G1-phase gate. To prepare G1-phase cells from continuously cycling cell populations, G1-phase HeLa cells were collected by centrifugal elutriation and highly synchronous S phase cells were obtained by double thymidine block followed by centrifugal elutriation. A G1-phase subtractive cDNA library was prepared by subtracting G1-phase cDNA with a 10-fold excess of S-phase mRNA. Single-stranded, G1-phase cDNAs were isolated by oligo(dA) chromatography. The library was screened with a high R0t fraction subtractive probe population. Following two rounds of screening, 20 positive clones were obtained. Northern blot analysis indicated that six of these clones were enhanced in expression level during G1 phase when compared with S phase. Nucleotide sequence comparison of each clone with the GenBank data base revealed that hG1.11 was highly homologous (99%) to the apoferritin light chain gene and clones hG1.6, hG1.10, hG1.17, and hG1.18 represented new G1-phase-enriched members of four human ribosomal protein gene families (71-95% homology). The last clone, hG1.1, encoded a highly charged polypeptide not previously identified. Additional study of these G1-phase-enriched mRNAs will be required to determine their role in cell cycle progression and the G1-phase gateway through which cells transit as they proceed through the cell cycle.

Actins↗
PubMedDate not supplied

Detection of plasma alpha-granule membrane protein GMP-140 using radiolabeled monoclonal antibodies in thrombotic diseases.

There is an assumption that platelet activation and endothelium damage play a critical role in the pathogenesis of thrombotic disorders. A radioimmunoassay based on using two monoclonal antibodies (MAbs) to different epitopes of alpha-granule membrane protein (GMP-140) was used to determine whether plasma GMP-140 can be detected in patients suffering from acute myocardial infarction (AMI) or cerebral thrombosis and in patients during cardiopulmonary bypass (CPB). MAb SZ-51 was used as a solid phase, and 125I-labeled MAb S12 was used as a fluid phase. The assay is so sensitive that it can detect as little as 1 ng/ml of purified GMP-140. The intra- and interassay coefficients of variation were 4.2% (n = 5) and 7.1% (n = 8), respectively. The concentration of plasma GMP-140 was found to be 10.0 +/- 4.5 ng/ml (mean +/- SD, n = 20) in normal subjects. Ten patients undergoing CPB demonstrated a transient increase in the concentration of plasma GMP-140, especially at 2 h after CPB, and the plasma GMP-140 level was inversely correlated with the decreased platelet counts during bypass (r = -0.81, p < 0.01). It was found that the concentration of plasma GMP-140 increased significantly after AMI. Plasma GMP-140 reached the peak within 3 days and changed with the process of AMI (n = 16) patients. The concentration of plasma GMP-140 increased significantly in patients with cerebral thrombosis in the acute phase but not after relief.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗