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Biomedical subjects

R L Beamer

Publications and source records attributed to R L Beamer.

At least 19 recordsLinked to original sources
PubMed2000

Factors influencing a woman's choice to undergo breast-conserving surgery versus modified radical mastectomy.

BACKGROUND: The use of breast-conserving surgery (BCS) rather than modified radical mastectomy (MRM) for the treatment of breast carcinoma is an option for the majority of women (75%) with early stage breast cancer, but only 20% to 50% choose to undergo this procedure nationwide. The objective of this study was to identify factors influencing a woman's choice between BCS and MRM, and specifically, the surgeon's influence on this choice. METHODS: A total of 134 women eligible for BCS were sent a survey. Data obtained included demographics, influential factors in treatment choice, and satisfaction with preoperative discussion and postoperative results. RESULTS: Ninety-six women completed the questionnaire. Mean patient age was 62 years. Most women surveyed felt their treatment options were satisfactorily explained to them. BCS, MRM with reconstruction (MRM-R), and MRM without reconstruction (MRM-NR) were performed in 45%, 15%, and 40% of patients, respectively. Overall, the most influential factor was the fear of cancer. Women choosing BCS indicated that the surgeon, cosmetic result, and psychological aspects were more influential in their decision than in women undergoing MRM-NR (P <0.02). Fear of cancer was the most important factor affecting the choice to undergo MRM-NR. In comparing MRM-R with MRM-NR, there was a similar fear of cancer; however, MRM-R had much greater concern with cosmesis (P = 0.0002). CONCLUSION: The surgeon's input is important in a woman's choice to undergo BCS or MRM-R. However, it appears that if a woman wants to have MRM-NR, even when she is a candidate for BCS, the surgeon's input is overshadowed by the patient's fear of cancer.

Adult↗
PubMed2000

Seroma formation after breast cancer surgery: incidence and predicting factors.

The pathophysiology of seroma formation has yet to be determined. Therefore, the present study was undertaken to calculate the incidence of postoperative seromas after definitive breast cancer operations utilizing electrocautery dissection. Additionally, we attempted to identify risk factors associated with seroma development and to examine seroma formation in relation to operative procedure. A retrospective review of 252 breast cancer operations was undertaken. Patients were subdivided by operative procedure: modified radical mastectomy (MRM; n = 148), breast preservation with axillary node dissection (n = 64), or MRM with immediate reconstruction (n = 40). Electrocautery was used in development of skin flaps. Seromas developed in 39 of the 252 operations for an incidence of 15.5 per cent. Seroma formation was significantly lower in those patients receiving MRM with immediate reconstruction than in those receiving MRM (2.5% vs 19.6%; P = 0.009) and tended to be lower than for patients receiving breast preservation with axillary node dissection (14.06%; P = 0.052). Neoadjuvant chemotherapy was performed in 18 patients, of whom 6 developed seromas (P = 0.030). The incidence of postoperative seromas was low despite the use of electrocautery. An association of postoperative seromas with neoadjuvant chemotherapy was noted. Additionally, it appears that immediate reconstruction may reduce the incidence of postoperative seromas, presumably by filling the dead space in the chest wall.

Adult↗
PubMed1994

Laparoscopic cholecystectomy in a freestanding outpatient surgery center.

Laparoscopic cholecystectomy in a freestanding outpatient surgery center was evaluated. Fifty-five patients undergoing laparoscopic cholecystectomy during a 10-month period from December 1992 to October 1993 were included in this study. There were 10 males and 45 females, with a mean age of 42 years. All patients had a history consistent with biliary colic. Forty-nine patients had documentation of cholelithiasis by ultrasonography, 3 had documentation of cholelithiasis by other diagnostic procedures, and 3 had a diagnosis of biliary dyskinesia. The mean surgery time was 75 min, with a range of 43-145 min. Fifty-four intraoperative cholangiography attempts were made, and 81% were successful. In 19%, intraoperative cholangiography was unsuccessful secondary to a small cystic duct. Fifty of the patients (90%) in this study were discharged from the surgery center without significant sequelae. Four patients were admitted to the hospital postoperatively, 1 for bradycardia, 1 for nausea, 1 for i.v. antibiotics secondary to purulent cholecystitis, and 1 for inability to maintain an adequate oxygen saturation. Another patient was admitted 1 week postoperatively for right upper quadrant pain. After a negative hepatobiliary scan, this patient was discharged without sequelae. The average facility charge of laparoscopic cholecystectomy in this series was $2300, compared with the average charge of $6500 in our community hospital. We conclude that laparoscopic cholecystectomy can be performed safely and cost effectively in a freestanding outpatient surgery center with proper patient selection.

Adult↗
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↗
PubMed1982

Synthesis and bioevaluation of a series of alkyl ethers of p-N,N-bis(2-chloroethyl)aminophenol.

A series of even numbered normal alkyl ethers (C2-C14) of p-N,N-bis(2-chloroethyl)aminophenol were synthesized and evaluated as to acute toxicity in mice and effects on survival in L-1210 leukemic mice. All of the ether derivatives demonstrated significantly lower acute toxicity than the parent phenol mustard. Significant survival times (greater than or equal to 125%) were obtained with all compounds except the hexyl derivative. The decyl ether produced the greatest significant increase and the ethyl ether the lowest significant increase in mean survival time. Significant survival times were produced at four dosage levels for the butyl, decyl, and dodecyl derivatives, three dosage levels for the octyl and tetradecyl derivatives, and one dosage level for the ethyl derivative.

Aniline Mustard↗
PubMed1982

Synthesis and bioevaluation of a series of fatty acid esters of p-[N,N-bis(2-chloroethyl)amino]phenol.

A series of even numbered fatty acid esters (C2-C18) of p-[N,N-bis(2-chloroethyl)amino]phenol were synthesized and evaluated as to acute toxicity as well as effectiveness against L-1210 mouse leukemia. The acetate through the decanoate derivatives demonstrated toxicity between 2 and 3 times that of phenol mustard in HA/ICR mice. The less soluble laurate, myristate, palmitate, and stearate derivatives were less toxic. Significant survival times in the leukemia studies (T/C% greater than or equal to 125) were observed for all compounds except the acetate and hexanoate derivatives. The myristate derivative produced the greatest significant increase in survival time, 162%. The palmitate and stearate derivatives produced significant survival at five and four dosage levels, respectively. The butyrate and laurate derivatives produced significant survival at three dosage levels and the octanoate, decanoate, and myristate at two dosage levels.

Aniline Mustard↗
PubMed1980

Interaction of L- and D-3-amino-1-chloro-2-pentanone with gamma-glutamylcysteine synthetase.

The optical isomers of 3-amino-1-chloro-2-pentanone, which are the alpha-chloroketone analogs of L- and D-alpha-aminobutyrate, were synthesized and found to be highly potent irreversible inactivators of gamma-glutamylcysteine synthetase. These chloroketones are 20 to 30 times more active than L-2-amino-4-oxo-5-chlorpentanoate. L- and D-Glutamate, in the presence of Mg2+ or Mn2+, protect the enzyme against inactivation. The enzyme is almost completely inhibited by cystamine under conditions in which 0.5 mol of this compound is bound/mol of enzyme. Treatment of the enzyme with cystamne, which produces inhibition that is reversible by dithiothreitol, prevents the interaction of the new chloroketones, L-2-amino-4-oxo-5-chloropentanoate and methionine sulfoximine with the enzyme. The findings suggest that a sulfhydryl group at the active site interacts with the chloroketones and with cystamine and that the chloroketone inhibitors and cystamine bind to the enzyme as glutamine analogs. The data also suggest that a gamma-glutamyl-S-enzyme intermediate may be formed in the reaction catalyzed by this enzyme.

Animals↗