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Biomedical subjects

R L Beamer

Publications and source records attributed to R L Beamer.

7 recordsLinked to original sources
PubMed1992

Laparoscopic cholecystectomy in a private community setting.

In order to evaluate early results and safety of laparoscopic cholecystectomy in community hospitals, the charts of 380 consecutive patients, scheduled between February 8 and November 28, 1990, were reviewed. There were 294 women and 86 men, with a mean age of 48 years. Forty-one patients required conversion to open cholecystectomy, for reasons including adhesions in 18 patients, intraductal filling defects in 11, marked inflammation in 6, excessive bleeding in 3, poor visualization of the operative field in 2, and gangrenous gallbladder in 1. Hospital stay (excluding patients converted to laparotomy) ranged from 0.29-18 days, with a mean of 1.4 days. Operative time ranged from 29-280 min, with a mean of 114 min. Cystic duct operative cholangiography was performed in 71% of patients. In 29%, operative cholangiography was either not performed at all or was attempted and unsuccessful, due to inability to cannulate the cystic duct. Procedure-related morbidity was 2.6%, which includes three common bile duct injuries, three intraabdominal abscesses requiring drainage, and one pneumonia. There was one death resulting from respiratory failure. Our results compare favorably with those reported in the literature. We conclude that laparoscopic cholecystectomy in community hospitals is a safe procedure in properly selected patients.

Cholangiography↗
PubMed1991

New options for treating gallstone disease.

Gallstone disease is a major health problem in the United States and in most Western countries. During the past century, cholecystectomy has been the treatment of choice. Recently, new modalities of treatment have been developed, including oral dissolution therapy, extracorporeal shock-wave lithotripsy, percutaneous transhepatic cholecystolitholysis using methyl tert-butyl ether, and laparoscopic cholecystectomy. In selected patients, these new options have been successful in the treatment of gallstones.

Cholecystectomy↗
PubMed1988

Molecular orbital calculations of proton transfer energetics in model systems: the interaction of opiate agonists and antagonists with opiate receptors.

Semiempirical (CNDO) molecular orbital calculations, based on a previously investigated morphine-receptor clastic-binding system, were performed using a series of ethyl and propyl amines as models for the analgesic receptor. Trimethyl and dimethyl amines were chosen to represent the opiate and noropiate agonist molecules. The opiate antagonist molecules, levallorphan, naloxone, nalorphine, and pentazocine were represented by a series of allyl and dimethylallyl amines. The results using these systems paralleled those of our previous investigations. The potential energy curves for all the systems studied had two minima at an internuclear distance of greater than 0.275 nm. At 0.2731 nm (the optimized N-N distance), the potential energy curve of some systems had single minima. The agonist systems studied had optimum energy curves for the conformer in which the (drug nitrogen-hydrogen) bond is equatorial. The noropiate model had the greatest transfer potential, an optimal condition for analgesic activity. The antagonist drug receptor models had energy curves that indicated a decreased proton transfer barrier that was similar to the noropiate case (although no delta E was obtained). The two largest models studied had energy curves that indicated decreased or inhibited proton transfer. The systems investigated had small deprotonation barriers, indicating deprotonation would most likely occur following protonation of the receptor.

Chemical Phenomena↗
PubMed1986

Molecular orbital calculations of proton transfer involving amines as models for the clastic binding of opiates with their receptor.

Semi-empirical (CNDO) molecular orbital calculations, based on a previously reported ammonia-amine model system, were performed on an extended series of methyl-, ethyl-, and propylamines as models for the analgesic receptor. Methyl-, dimethyl-, and trimethylamines were chosen to represent the opiate molecules. Interatomic distances were varied within normally expected biological values. The results for the larger systems are similar to more elaborate calculations previously reported using smaller molecules. At internuclear distances of greater than 0.275 nm, the potential energy curves had two minima. At 0.2731 nm, the optimized N-N distance, the "depth" of the minima in the potential energy curve were not as great. Energy differences as well as population differences suggest deviation from the currently stated clastic binding theories mechanism for the analgesic response of the tertiary amines. The dimethylamine energy profile and population data indicate that the hypothesis of N-demethylated opiate as the active molecule needs further consideration and investigation. Investigation of larger systems is also indicated to develop increasingly realistic models for the analgesic response.

Amines↗
PubMed1985

Incidence and associated mortality of retained common bile duct stones.

A hundred consecutive patients who underwent cholecystectomy and exploration of the common bile duct were studied. The traditional indications for exploration resulted in a yield of 55 percent positive explorations. There were nine patients with retained stones, three of whom died. The high mortality rate of patients with retained stones stresses the importance of systematic and thorough exploration of the biliary tree during initial operation. Choledochoscopy, when combined with cholangiography, may decrease the incidence of retained stones.

Adolescent↗