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Biomedical subjects

G Wu

Publications and source records attributed to G Wu.

At least 649 records · Page 36Linked to original sources
PubMed1982

The demonstration of lymphatic channels on wrist arthrography in rheumatoid disease with particular reference to associated lymphoedema.

Delineation of lymphatic vessels is a frequent finding in arthrograms of rheumatoid joints. Arthrography of the rheumatoid wrist when associated with oedema of the upper limb reveals a characteristic pattern consistent with lymphatic obstruction. In our opinion, these findings may be regarded as further evidence in favour of lymphatic obstruction as the cause of peripheral oedema in rheumatoid arthritis. The syndrome appears to be a separate entity from idiopathic oedema of women.

Adult↗
PubMed1982

Arrangement of lambda light chain genes in mutant clones of the MOPC 315 mouse myeloma cells.

The synthesis of lambda light chains and the arrangement of the lambda-chain genes was examined in cells of the mouse myeloma MOPC 315, which is an alpha lambda 2 producer, and in several mutants derived from it. The mutants produce lambda 2 chains only (MOPC 315.26, MOPC 315.34, and MOPC 315.37) or fail to produce alpha and lambda 2 chains (MOPC 315.25 and MOPC 315.36). Messenger RNA from the lambda 2 chain-producing cells directed the synthesis of a lambda 2 chain precursor and a fragment of the lambda 1 chain (lambda 1 F) in a wheat embryo cellfree system, whereas mRNA from the cells that do not produce lambda 2 chains directed the synthesis of lambda 1 F only. DNA from the parental MOPC 315 cells and from the lambda 2 chain-producing cells contained discrete EcoRI restriction fragments coding for rearranged lambda 1 and lambda 23 chain genes and their respective germ-line V and J-C regions. DNA from the no-Ig-producing cells contained fragments coding for the rearranged lambda 1 chain gene and the germ-line V lambda 2 region, but it lacked the sequences coding for the rearranged lambda 2 chain gene and the germ-line V lambda 1 and J-C lambda 1 regions. These results suggest that rearrangements of the lambda 1 and lambda 2 chain genes occur on different chromosomes in MOPC 315 cells and imply that rearrangements of the lambda 1 and lambda 2 chain genes on the same chromosome may be mutually exclusive.

Animals↗
PubMed1978

THe hazards of injecting local anesthetic solutions with epinephrine into flaps: experimental study.

In a study using paired longitudinal flaps on the back of the rat, we found evidence to support the findings of previous investigators regarding the toxic effects of injecting local anesthetic solutions containing epinephrine into delayed flaps. Epinephrine concentrations of 1:200,000 and 1:400,000 were demonstrated to significantly increase losses in these flaps. Epinephrine concentrations of 1:100,000, 1:200,000, and 1:400,000 were not demonstrated to be harmful to undelayed flaps, in the dosages used.

Aged↗
PubMedDate not supplied

Methylmercury-cysteine uptake by rat erythrocytes: evidence for several transport systems.

The present study is a continuation of our experiments on methylmercury-cysteine (MeHg-cysteine) uptake by rat red blood cells (RBCs) at low temperature. Methylmercury-cysteine uptake by rat RBCs was conducted at 5 degrees C and 20 degrees C. The effects of Ca2+, colchicine, cytochalasin B, 4,4'-diisothiocyano-2,2'-stilbenedisulphonic acid (DIDS), N-ethylmaleimide (NEM), D-glucose, hexanol, L-homocysteine, ouabain, probenecid, sodium fluoride (NaF), vinblastine, and anisotonic changes on MeHg-cysteine uptake were examined. The results showed that MeHg-cysteine uptake at 5 degrees C could be described by Michaelis-Menten kinetics (v = VmaxS/(S+Km), where Km = 37.02 mM and Vmax = 320.84 mmol l-1 RBCs h-1), but MeHg-cysteine uptake at 20 degrees C could be described by Michaelis-Menten kinetics with a linear component (v = [VmaxS/(S + Km)] + KdS, where Km = 2.71 mM, Vmax = 250.72 mmol l-1 RBCs h-1, and Kd = 5.63 mM). Methylmercury-cysteine uptake was inhibited by colchicine, cytochalasin B, D-glucose, hexanol, NaF, NEM, ouabain, probenecid, vinblastine and 230 mosM hypotonicity but stimulated by Ca2+, DIDS, L-homocysteine and 460 mosM hypertonicity. The results in the present study suggest that MeHg-cysteine uptake by rat RBCs might be involved in the following three transport systems: an energy transport system sensitive to Ca2+, ouabain and NaF and subjected to Michaelis-Menten kinetics; an organic anion transport system sensitive to probenecid; and a facilitated diffusive transport for D-glucose sensitive to cytochalasin B. It is likely that most of the transport systems work at temperatures higher than 5 degrees C.

Animals↗
PubMedDate not supplied

Uptake of methylmercury cysteine by rat erythrocytes at lower temperature.

Methylmercury cysteine (MeHg-cysteine) uptake by rat erythrocytes (RBC) was undertaken at 5 and 20 degrees C. The effects of several amino acids, their derivatives, ATP, Na+, Mg2+ and membrane potential on MeHg-cysteine uptake were examined. The results showed that MeHg-cysteine uptake was temperature-dependent, Na(+)-dependent at 20 degrees C, partly Na(+)-dependent at 5 degrees C and Mg(2+)-dependent at 5 and 20 degrees C. The membrane potential had a very slight effect on MeHg-cysteine uptake. N-Acetyl-L-cysteine (AC), alanine, beta-alanine, cysteine sulphinic acid (CSA), gamma-aminobutyric acid (GABA), D-phenylalanine, phenylalanine, serine and taurine inhibited MeHg-cysteine uptake at 5 degrees C. Tryptophan both stimulated and inhibited at different sampling times at 5 degrees C. Glycine and methionine had stimulation at 5 degrees C. Aspartic acid, isoleucine, leucine and tyrosine had no effect on MeHg-cysteine uptake. GABA, D-phenylalanine and tryptophan lost their effects at 20 degrees C. The effects of glycine and serine had reversed at 20 degrees C. The half-time of MeHg-cysteine uptake was ca. 0.57 h at 5 degrees C and 0.23 h at 20 degrees C. Several amino acids and their derivatives had an influence on the half-times of MeHg-cysteine uptake. The present study suggested that MeHg-cysteine uptake by rat RBC at lower temperature involved several overlapping transport systems; the greatest contribution was likely to be due to system ASC. Direct evidence for system L in MeHg-cysteine uptake was not obtained in the present study.

Adenosine Triphosphate↗
PubMedDate not supplied

No involvement of system N, system y+ and the oligopeptide-H+ transport system in the uptake of methylmercury in rat erythrocytes.

Previous studies have investigated a number of possible transport systems for the uptake of methylmercury (MeHg) in erythrocytes. In the present study, three additional systems were studied. The uptake of MeHg by isolated erythrocytes from rats was studied at 5 degrees C and 20 degrees C. Glutamine was used to test system N and system y+, and glycylglycine was used to test the oligopeptide-H+ transport system. The Hill equation was used in kinetic analysis. The results show that both glutamine and glycylglycine stimulated the uptake of MeHg, but the stimulation by glycylglycine is stronger than by glutamine, and the stimulation at 5 degrees C is stronger than at 20 degrees C (mean values are 167.98% and 83.68% in the glycylglycine group at 5 degrees C and 20 degrees C versus 26.28% and 19.23% in the glutamine group at 5 degrees C and 20 degrees C). The kinetic analysis shows that: the Michaelis-Menten constant Km increased as temperature increased in both groups and was larger in experimental groups than in control groups; the Hill constants increased as temperature increased in both groups and were smaller in experimental groups than in control groups; and as temperature increased, maximum velocity Vmax increased in control groups and decreased in experimental groups, and was larger in experimental groups than in control groups, with the exception of the glycylglycine group at 20 degrees C. The results demonstrated that system N, system y+ and oligopeptide-H+ transport systems were not involved in the in vitro uptake of MeHg into erythrocytes. The stimulation by glutamine and glycylglycine might be related to some signalling pathways, through which nitric oxide and oligopeptide serve as messengers and cause functional alterations in the uptake of MeHg.

Amino Acid Transport Systems↗
PubMedDate not supplied

NMR study and comparison of the antigenic properties of a peptide recognized by two HIV-1 neutralizing antibodies.

Fab-peptide complexes formed between a 15 residue peptide derived from the HIV-1 gp120 V3 loop and two of its cognate monoclonal antibodies, 5023A and 5025A, were studied using isotope-edited solution nuclear magnetic resonance (NMR) techniques. Since these antibodies neutralize HIV-1 virus with different strain specificities, this study was conducted to better understand the nature of these differences. The amide proton and nitrogen NMR resonances of specific residues were used to monitor the backbone of this peptide in these complexes. Three central residues of this peptide ('RAF') were found to be strongly affected by binding to both antibodies. Several other peptide residues were affected by binding to antibody 5023A but not 5025A. The antibody epitopes mapped by NMR are similar to those obtained previously via PEPSCAN at higher pH. One main difference between the PEPSCAN and NMR determined epitopes for 5023A involved two glycine residues of the peptide. By NMR, one of these glycines was more dramatically affected by antibody binding than predicted by PEPSCAN, while the other was much less so.

Antibodies, Monoclonal↗
PubMedDate not supplied

Bilirubin mono- and diglucuronide formation by human liver in vitro: assay by high-pressure liquid chromatography.

Bilirubin diglucuronide, the major pigment in human bile is formed in two steps. Bilirubin is converted to bilirubin monoglucuronide by transfer of the glucuronosyl moiety of uridine diphosphoglucuronic acid catalyzed by the microsomal enzyme, uridine diphosphoglucuronate glucuraonosyl transferase (UDP glucuronyl transferase, EC 2.4.1.17). Bilirubin monoglucuaronide is converted to bilirubin diglucuronide in vitro by two enzymatic mechanisms: (a) UDP glucuronyl transferase-mediated transfer of a second mole of glucuronic acid form UDP-glucuronic acid to bilirubin monoglucuronide; (b) dismutation of 2 moles of bilirubin monoglucuronide to 1 mole of bilirubin diglucuronide and 1 mole of unconjugated bilirubin, catalyzed by bilirubin monoglucuronide dismutase (bilirubin glucuronoside glucuronosyl transferase EC 2.4.1.95). Assay methods for the three enzymatic mechanisms in human liver homogenate by high-pressure liquid chromatography analysis of underivatized bilirubin tetrapyrroles have been developed. UDP glucuronyl transferase was activated in five human liver homogenates with digitonin, Triton X-100, or UDP-N-acetylglucosamine. Greatest activation was observed with Triton X-100. The pH optimum for conversion of bilirubin to bilirubin monoglucuronide was 7.4, and UDP glucuronyl transferase activity was 625 +/- 51 nmoles per 20 min per gm liver. At high initial bilirubin concentrations (342 microM), the product of UDP glucuronyl transferase assay with bilirubin as substrate was predominantly bilirubin monoglucuronide. At lower initial bilirubin concentrations (6.5 to 34 microM), up to 15% bilirubin diglucuronide was formed. Glucuronyl transferase-mediated UDP glucuronic acid-dependent conversion of bilirubin monoglucuronide to diglucuronide was assayed using UDP-14-C-glucuronic acid. The pH optimum was 7.4, and the rate was 21 +/- 7 nmoles per gm liver per 20 min. The rate of bilirubin diglucuronide formation by enzymatic dismutation of bilirubin monoglucuronide was 470 +/- 112 nmoles per gm liver per min. The pH optimum was 6.6. The products of enzymatic dismutation were of the IX alpha configuration.

Bilirubin↗
PubMedDate not supplied

Prediction of blood cyclosporine concentrations in haematological patients with multidrug resistance by one-, two- and three-compartment models using Bayesian and non-linear least squares methods.

The blood cyclosporine (CsA) concentration-time profile in each of 24 adult haematological patients with multidrug resistance taking the first course of CsA treatment was fitted by one-, two- and three-compartment models to obtain relevant pharmacokinetic parameters. The pharmacokinetic parameters obtained were implemented into the PKS program (Abbottbase Pharmacokinetic System) as the population pharmacokinetic parameters used to predict blood CsA concentrations in adult haematological patients with multidrug resistance. The predictions of blood CsA concentrations by one-, two- and three-compartment models using the Bayesian method (BM) and the non-linear least squares method (NLLSM) were evaluated employing 11 patients who took the second course of CsA treatment. While the Akaike's information criterion (AIC) favoured the two-compartment model to describe CsA concentration-time profiles in patients taking the first and second courses of CsA treatment, the predictive performance analyses showed that both two- and three-compartment models were better than the one-compartment model for prediction, but the three-compartment model was slightly superior to the two-compartment model. The results also show that the predictions using BM were slightly better than those using NLLSM. Several factors affecting BM predictions and the possible difference among AIC, BM and predictive performance analyses were also addressed.

Acute Disease↗
PubMedDate not supplied

High-field 127I NMR of solid sheelite structures: periodates revisited.

We report new solid-state 127I NMR results for sheelite periodates, MIO4 (M = Na+, K+, Rb+, and NH4+), and for pseudo-scheelite CsIO4 and HIO4. The observed 127I quadrupole coupling constants were between 1.0 and 43.0 MHz in agreement with previous NQR data. In contrast to an early 127I NMR study (S. L. Segel and H. M. Vyas, 1980, J. Chem. Phys. 72, 1406), we found that the 127I chemical shift anisotropy is negligibly small in sheelite periodates. A small but definite 127I chemical shift tensor was observed for pseudo-scheelite CsIO4.

Iodine Isotopes↗