PubMed Health⌕ Search

Biomedical subjects

R Wang

Publications and source records attributed to R Wang.

At least 685 records · Page 38Linked to original sources
PubMed1989

Tracheoesophageal puncture for voice restoration after extended laryngopharyngectomy.

Tracheoesophageal puncture was performed in ten of our patients undergoing extended laryngopharyngectomy. Three fistulas were allowed to close, and two patients were dissatisfied with their results, which allowed for an overall 50% success rate in this subgroup. The resultant voice was objectively compared with similar groups of patients undergoing primary and secondary tracheoesophageal puncture after standard laryngectomy. There was no significant difference in maximum phonation time, average speaking intensity, and average fundamental frequency between these groups. However, the maximum intensity and average intensity were significantly lower for the flap group. Our results indicate that tracheoesophageal puncture should be attempted in patients undergoing the extended procedure, notwithstanding a lower expected success rate.

Aged↗
PubMed1989

Two types of calcium channels in isolated smooth muscle cells from rat tail artery.

Whole cell patch-clamp recordings were carried out on smooth muscle cells from rat tail artery in short-term culture to verify the existence of and to characterize the calcium channels that are present. Two types of voltage-dependent calcium channels were identified in 55 of 63 cells studied. The T-type calcium channel was activated at -50 mV, and the peak inward current occurred at -10 mV, whereas the L-type channel was activated at -20 mV, and the peak inward current occurred at +10 or +20 mV. The T-type channel current inactivated quickly in contrast to the much slower inactivation of the L-channel current. The voltage dependence of steady-state inactivation of the two channels was similar to that reported for other vascular smooth muscle preparations. An internal solution containing Cs2-aspartate maintained the calcium-channel currents for at least 20 min with only a 5-10% decline. BAY K 8644 had no effect on T-channel currents, but the L-channel current was increased by at least a factor of two. In addition, BAY K 8644 shifted the activation threshold, the peak inward current, and the steady-state inactivation-activation curves of L-type channel currents in the direction of hyperpolarization.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1989

Study of in vitro antibacterial activity of 19 antimicrobial agents against Pseudomonas aeruginosa.

The in vitro antibacterial activity of 19 antimicrobial agents against 40 strains of P aeruginosa was studied. The 19 antimicrobial agents included 7 semisynthetic penicillins, 6 third generation cephalosporins, 5 aminoglycosides and 1 quinolone agent. The minimal inhibition concentrations (MIGs) were measured by the serial dilution on solid agar. Ceftazidime was the most active in 19 antimicrobial agents again P aeruginosa (MIC50: 1 microgram/ml, MIC90: 2 micrograms/ml) Amikacin and ofloxaxin followed it in activity. Acylureido-penicillins, such as azlocillin, furbenicillin and piperacillin were highly active against P aeruginosa, which could inhibit, 92.5%, 90% and 85% of these strains at a concentration of 8 micrograms/ml. Cefsulodine and cefoperazone were also active against the same strains, inhibiting 92.5% and 99% of the strains at a concentration of 8 micrograms/ml. The potency of the agents mentioned above against P. aeruginosa was similar to that of aminoglycosides. The drug susceptibility of 10 strains isolated in our hospital was compared with that of 29 strains of other hospitals in Beijing. The MICS of 5 penicillins and 3 cephalosporins against the isolates of our hospital was higher than that of other hospitals, suggesting that the susceptibility of beta-lactam antibiotics against isolates of our hospital was lower. The effects of combined use of azlocillin with oxacillin and piperacillin with ofloxacin against 4 strains of carbenicillin-resistant P aeruginosa was studied using check-board testing. The synergy and partial synergy were observed in both combinations.

Azlocillin↗
PubMed1989

[Pathologic comparison between gastric carcinoma and lesions in peri-cancerous mucosa from two districts with different mortality rates in Gansu Province].

A pathologic comparative study on gastric carcinoma and lesions in peri-cancerous mucosa was done in 222 resected specimens of gastric carcinoma from two districts with different mortality rates in Gansu province. The adjusted mortality rates were 46.41 per 100,000 and 21.64 per 100,000 respectively. There were no significant difference in the histologic type and the gastric, intestinal and mixed types classified according to mucin histochemical stain and no significant difference in the detection rate of chronic atrophic gastritis (CAG), intestinal metaplasia (IM) and dysplasia in peri-cancerous mucosa either. These findings suggest that the type of gastric carcinoma be not related to the mortality rates either high or low and neither was there any apparent correlation between the CAG, IM and gastric carcinoma.

Adenocarcinoma↗
PubMed1988

Effect of probucol on development of diabetes mellitus in BB rats.

Insulin-dependent diabetes mellitus (IDDM) results from an inflammatory process leading to destruction of the insulin-producing beta cells of the pancreas. Genetically mediated autoimmune processes are considered the most likely explanation for IDDM in humans, while viral infections, toxic agents, nutritional alterations and stress are also considered possibilities. The precise mechanisms by which autoimmunity, infections, toxins or other agents produce beta cell damage are not known. Toxin-induced diabetes in animals can be prevented by antioxidant therapy, while an agent that inhibits hydroxyl radical formation, desferrioxamine, extends the survival time of free allotypic islets in nonobese diabetic mice. The BB/W rat develops IDDM secondary to a pervasive autoimmune defect. This well-studied animal model develops IDDM with a highly predictable frequency and timing. This study describes the effects of the potent antioxidant, probucol, on the development of diabetes in BB rats by introducing it into standard rat chow at a 1% concentration at the time of weaning, and continuing this feeding schedule through 160 days of life. Control rats from split litters received standard chow only. Diabetes developed in 86.2% of the control rats at a mean age of 90.4 days. Probucol administration was associated with a reduction to 62% and a delay in diabetes diagnosis to 99.6 days. These very preliminary results suggest that probucol may be altering the inflammatory process, resulting in beta cell destruction in these genetically diabetes-prone rats.

Actuarial Analysis↗
PubMed1988

The synthesis of protective fragments of alpha-human atrial natriuretic polypeptide (alpha-hANP).

In this paper the synthesis of alpha-human atrial natriuretic polypeptide fragments (positions, 1-4, 5-10, 11-16, 17-22, 23-28) by solution method is reported. In the synthesis of some peptides, the results from mixed anhydride procedure and active ester procedure are compared. In the synthesis of other peptides, the effects of reaction temperature, basicity of catalyst, and reaction time on the specific rotations and yields of these compounds are observed. The sequence of amino acids of all the protective polypeptides is confirmed by FAB-MS.

Atrial Natriuretic Factor↗
PubMed1987

Phosphorylation heterogeneity of tryptic phosphopeptides of chicken riboflavin-binding protein.

The tryptic phosphopeptide of hen egg white riboflavin-binding protein has been found to exist as a mixture of peptides which differ only with respect to the number of covalently bound phosphoryl groups. Anion-exchange chromatography was used to separate homologues of the tryptic phosphopeptide of egg white riboflavin-binding protein. Four peptide peaks were obtained and analyzed using plasma desorption mass spectrometry. Molecular ions obtained agree closely with calculated molecular weight values for phosphopeptides with 8, 7 and 5 phosphoryl groups. Amino acid analyses showed that the octa- and hepta-phosphorylated peptides were pure and had the same amino acid compositions.

Animals↗
PubMed1987

Effects of chemical smokes on flora and fauna under field and laboratory exposures.

Various types of obscurant smokes are used routinely in training by the U.S. Army. Because continued routine use of the smokes could be detrimental to the native flora and fauna at training sites, a preliminary biological and chemical field study of fogoil, hexachloroethane, and tank diesel smokes was conducted. Smoke plumes were sampled and chemically analyzed at distances of 15-150 m from the smoke source where Tradescantia clones 4430 and 03 and the native plant Ambrosia dumosa and the native rodent Dipodomys merriami were exposed for 30 min. In addition, Tradescantia clone 4430 was exposed to tank diesel in the laboratory at concentration levels equivalent to exposure at 15 and 50 m. Tradescantia clones were examined for mutagenic effects indicated by micronuclei induction in developing pollen and pink somatic mutations in stamen hairs. Photosynthetic perturbations were measured in Tradescantia and A. dumosa using variable fluorescence induction. Animals were examined for sister chromatid exchanges and chromosome aberrations. It was found that all of the smokes tested exerted varying degrees of physiological and mutagenic effects in one or more assay system at one or more exposure distance. The studies reported here indicate that exposed ecological systems, or at least components of these systems, are at a higher risk than are unexposed components (e.g., organisms) for several types of damage attributed to obscurant smoke exposure.

Animals↗