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Biomedical subjects

D W Wang

Publications and source records attributed to D W Wang.

At least 73 records · Page 4Linked to original sources
PubMed1985

Anaerobic infections of burns.

From August 1980 to June 1982, 102 burn wound specimens taken from 34 patients were studied for anaerobic cultures. Fifteen instances (14.7 per cent) from 8 patients were positive and altogether 12 species were found. The predominant anaerobes were Bacteroides melaninogenicus, Peptococcus, Bacteroides fragilis, and other strains of Bacteroides and Peptostreptococcus. They were mostly discovered in electric burn wounds and burn wounds affecting the perianal and oral areas. Wounds with anaerobic infection usually appeared gaseous, necrotic and ischaemic with foul odour. Nineteen blood samples from 10 burn patients were also studied for anaerobic cultures, and two were positive, one caused by Bacteroides and the other by mixed infection of Peptococcus and Serratia, indicating that the anaerobes played an important role in burn infections. It seems necessary to perform anaerobic culture studies in burn patients as a routine. A comparative study between anaerobic culture and indirect immuno-fluorescence method was undertaken for Bact. fragilis and Bact. melaninogenicus in 47 burn wounds. It showed that the immunofluorescence method was a more rapid, simple, sensitive and specific diagnostic method.

Adolescent↗
PubMedDate not supplied

Correlation between quinolone uptakes by BCECs in vitro and brain-to-plasma concentration ratios in rats.

Transport of 11 quinolones at the blood-brain barrier (BBB) was studied in vitro by using primarily cultured rat brain capillary endothelial cells (BCECs) and in vivo brain-to-plasma concentration ratios. In vitro, when cells reached confluence, a time course of quinolone uptake was recorded by incubation with a medium contraining quinolones 20 microg/ml at 37 degrees C. A simple two-compartment model was used for fitting the uptake time course and corresponding uptake parameters were estimated. In vivo rats were anesthetized, after in 10 mg/kg of quinoloes followed by infusion of 4 mg/kg/h for 2 hours, the drug concentrations in plasma and brain were measure and brain-to-plasma concentration ratios were calculated. Result showed that sparfloxacin and prulifloxacin have higher uptakes by BCECs and brain-to-plasma concentration ratios, compared with other quinolones, which indicated that the two drugs more easily penetrate into BBB. A good correlation between uptakes by BCECs and brain-to-plasma concentration ratios was found. These results demonstrated uptakes by BCECs in vitro might give prediction of brain-to-plasma ratio for quinolones.

Animals↗
PubMedDate not supplied

The use of blood in burn shock. Clinical and experimental study.

We have given whole blood as one of the main constituents of burn shock resuscitation for the past 28 years. To appraise the value of using whole blood, we have summarized the clinical experience of 2630 burn patients. Overall mortality was 4.18%. The lethal area of the burn were 50% of the population is expected to die was 82.8% total body surface area and 57.4% third-degree burns. The incidence of renal failure, pulmonary edema, and gastrointestinal bleeding was 0.9%, 0.4%, and 0.6% respectively. To confirm the advantage of transfusion of whole blood, we have carried out a series of experimental studies. Two groups of 25 dogs with 25% total body surface area full-thickness burns were treated with two resuscitation regimens. Group I was treated with whole blood, and group II with no blood, during the shock phase. After 48 hours, the infusions were stopped. Measurements were made before the burn and 2, 24, 48, 72, and 144 hours after the burn injury. The animals were then killed for histologic studies. From our data, we concluded that whole blood used in burn shock did not increase hemoconcentration or viscosity; it improved anemia, oncotic pressure, hypoproteinemia, acid-base balance, oxygenation, hemodynamics, and myocardial contractility, promoted cardionatrin secretion, reduced edema of tissue, and protected viscera from degenerative changes and bacterial colonization.

Animals↗
PubMedDate not supplied

Cardiac Na(+) channel dysfunction in Brugada syndrome is aggravated by beta(1)-subunit.

BACKGROUND: Mutations in the gene encoding the human cardiac Na(+) channel alpha-subunit (hH1) are responsible for chromosome 3-linked congenital long-QT syndrome (LQT3) and idiopathic ventricular fibrillation (IVF). An auxiliary beta(1)-subunit, widely expressed in excitable tissues, shifts the voltage dependence of steady-state inactivation toward more negative potentials and restores normal gating kinetics of brain and skeletal muscle Na(+) channels expressed in Xenopus oocytes but has little if any functional effect on the cardiac isoform. Here, we characterize the altered effects of a human beta(1)-subunit (hbeta(1)) on the heterologously expressed hH1 mutation (T1620M) previously associated with IVF. METHODS AND RESULTS: When expressed alone in Xenopus oocytes, T1620M exhibited no persistent currents, in contrast to the LQT3 mutant channels, but the midpoint of steady-state inactivation (V(1/2)) was significantly shifted toward more positive potentials than for wild-type hH1. Coexpression of hbeta(1) did not significantly alter current decay or recovery from inactivation of wild-type hH1; however, it further shifted the V(1/2) and accelerated the recovery from inactivation of T1620M. Oocyte macropatch analysis revealed that the activation kinetics of T1620M were normal. CONCLUSIONS: It is suggested that coexpression of hbeta(1) exposes a more severe functional defect that results in a greater overlap in the relationship between channel inactivation and activation (window current) in T1620M, which is proposed to be a potential pathophysiological mechanism of IVF in vivo. One possible explanation for our finding is an altered alpha-/beta(1)-subunit association in the mutant.

Amino Acid Substitution↗
PubMedDate not supplied

[Degenerative changes in neutrophils as an indicator of neonatal sepsis].

Detection of the degenerative changes of neutrophils (D.C.N.) including vacuolization and toxic granulation in peripheral blood smear can be of value in identifying neonates with infection. A prospective study of 264 neonates who required septic work-ups in the first month of life was conducted. Thirty neonates were proved to have sepsis subsequently. The accuracy of the degree of the D.C.N. to predict neonatal sepsis was assessed. Vacuolization and/or toxic granulation in neutrophils varied from 0% to over 50%/100 neutrophils scanned. The higher the degree of D.C.N. the greater was the like-hood of sepsis. The positive predictive accuracy and specificity increased with the degree of D.C.N. from 24.7% to 100% and 70% to 100% respectively, but the sensitivity decreased accordingly. When D.C.N. was less than 10% the chance of sepsis was less than 5%. Most of newborns dying of proven sepsis had higher percentage of D.C.N.. These findings suggest that degree of D.C.N. may be associated with the outcome of the patients. This simple test can be performed easily in all hospital; it does not require special laboratory facilities and provide a valuable adjunct in early detection of severity and outcome of the neonates with sepsis.

Cytoplasmic Granules↗
PubMedDate not supplied

O6-methylguanine-DNA methyltransferase and human cancer chemotherapy.

Two kinds of human tumor cell strains having different activity of O6-methylguanine-DNA methyltransferase (O6-MT) were transplanted into nude mice. Mice were then injected intraperitoneally (i.p.) with the bifunctional agent 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride(ACNU). The tumors with low O6-MT activity were quickly suppressed or cured. This result suggests that some tumors, if determined to have low O6-MT activity, might be cured if the host is treated with ACNU. This observation may open a new approach to experimental cancer chemotherapy. Treatment with ACNU of experimental animals bearing HeLaMR tumors (which have low O6-MT activity and are Mer-), resulted in the regression of the tumors or their disappearance. In animals bearing HeLaS3 tumors (which have high O6-MT activity and are Mer+) the tumors were hyperplastic.

Animals↗