Search PubMed⌕ Search

Biomedical subjects

C D Williams

Publications and source records attributed to C D Williams.

At least 73 records · Page 4Linked to original sources
PubMed1977

Major surgery in patients with chronic renal failure.

To determine the risks of performing major surgical procedures on patients with chronic renal failure, the charts of twenty-nine hemodialysis patients who underwent thirty-eight elective and nine emergency operations were reviewed. Preoperative preparation included adequate hemodialysis of the patients, 88 per cent of whom were dialyzed within 24 hours of surgery. Azotemia was well controlled prior to administration of anesthesia. The average preoperative hematocrit was 26 per cent, and only one patient was hyperkalemic preoperatively. There were no intraoperative complications attributable to the patients' impaired renal function. Postoperative complications were frequent and are discussed in detail. Hemodialysis was done immediately postoperatively in five patients and on the first postoperative day in twenty-three additional patients with no problems. There were only two deaths (4.3 per cent) in the series. With careful monitoring during the perioperative period, major surgical procedures can safely be performed on patients with chronic renal failure.

Adolescent↗
PubMed1976

"Prohibitive" lung function and major surgical procedures.

Sixteen patients with preoperative pulmonary function testing data placing them in the "prohibitive" range underwent major surgical procedures with one mortality (6 per cent) and three major pulmonary complications (19 per cent). All complications were after pulmonary resections in patients with marked muscular weakness. Patients should not be denied necessary operative procedures on the basis of pulmonary function testing placing them in the "prohibitive" range of the Miller quadrant diagram alone. This term should be changed to "increased risk."

Adult↗
PubMed1976

Isolation and characterization of dihydropteridine reductase from Pseudomonas species.

Dihydropteridine reductase isolated from the bacterium Pseudomonas species (ATCC 11299a) has been purified approximately 450-fold byammonium sulfate precipitation and diethylaminoethyl-cellulose chromatographic procedures. The preparation is at least 80% pure as judged by polyacrylamide gels. Its molecular weight was determined to be about 44,000. Both dihydropteridine reductase and phenylalanine hydroxylase activities were found to be higher in cells adapted to a medium containing L-phenylalanine or L-tyrosine as the sole carbon source than in those grown in L-asparagine. The substrate of the reductase is quinonoid dihydropteridine, and the product is tentatively identified as a tetrahydropteridine through its ability to serve as a cofactor for phenylalanine hydroxylase. The enzyme shows no marked specificity for the pteridine cofactor that occurs naturally in this organism, L-threo-neopterin. The pH optimum for the reductase is 7.2, and nicotinamide adenine dinucleotide, reduced form, is the preferred cosubstrate. Inhibition of the reduced and untreated enzyme by several sulfhydryl reagents was observed. A metal requirement for the reductase could not be demonstrated. Dihydropteridine reductase was found to be inhibited by aminopterin in a competitive manner with respect to the quinonoid dihydro form of 2-amino-4-hydroxy-6,7-dimethyl-5,6,7,8-tetrahydropteridine.

Aminopterin↗
PubMed1976

Effects of methylxanthines on gonadotropin-induced steroidogenesis and protein synthesis in isolated testis interstitial cells.

The effects of 1-methyl 3-isobutyl xanthine (MIX) and theophylline on basal and gonadotropin-stimulated production of cyclic AMP and testosterone were evaluated in enzyme-dispersed testicular interstitial cells. The actions of these compounds upon precursor incorporation into RNA and protein were also examined in the same cell preparation. The considerable higher potency of MIX as a phosphodiesterase inhibitor was accompanied by a steeper dose-response curve for cyclic AMP recovery in incubation media of hormone-treated cells. Both inhibitors caused increases in basal and hormone-stimulated cyclic AMP levels. Although low concentrations of theophylline and MIX had no effect on the maximum levels of hCG-stimulated testosterone production, 10 mM theophylline and 1 mM MIX significantly inhibited steroidogenesis. Conversely, basal testosterone levels were increased by MIX and theophylline. The higher concentrations of MIX and theophylline also significantly inhibited precursor incorporation into RNA and protein. These actions of phosphodiesterase inhibitors upon RNA and protein synthesis could contribute to their inhibitory effects at high concentrations upon gonadotropin-induced steroidogenesis.

Animals↗
PubMed1975

Influence of primary closure of the pericardium after open-heart surgery on the frequency of tamponade, postcardiotomy syndrome, and pulmonary complications.

Experiences with primary closure of the pericardium in a series of 100 patients undergoing open-heart operations are described. The pericardium was kept under tension during the operation to minimize shrinkage and permit closure at the end of the procedure. In 28 patients one pleural space was opened for drainage, whereas in 72 patients intra- and extrapericardial sumps alone were used for drainage. Measurements of sump drainage revealed that most postoperative bleeding originates from outside the pericardium. There were no instances of cardiac tamponade although 19 patients lost more than 1 L. of blood after operation and 5 required reoperation for hemorrhage. Transpleural drainage tubes were shown to be ineffective and in addition were associated with a fourfold increase in postcardiotomy syndrome and a significantly greater frequency of pleural effusion and atelectasis when compared to the use of mediastinal sump drainage alone. We have concluded that closing the pericardium and using mediastinal sump drainage minimizes the risk of cardiac tamponade and allows early localization of the site of postoperative bledding. Another advantage of pericardial closure and drainage is that postoperative adhesions and postcardiotomy syndrome will be less significant. As a consequence the danger of injuring the heart in a subsequent operation is lessened.

Adult↗
PubMed1975

Percutaneous cannulation of the femoral artery for monitoring.

This technique for the percutaneous placement of an intra-arterial cannula in the common femoral artery offers a simple method for the monitoring of blood pressure and blood gases. The morbidity of this procedure is low, and it is technically less difficult than radial artery cannulation.

Blood Pressure Determination↗