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Biomedical subjects

L Way

Publications and source records attributed to L Way.

At least 19 recordsLinked to original sources
PubMed1996

Assessing a virtual reality surgical skills simulator.

The Institute for Defense Analyses (IDA) was contracted to perform a military standard task analysis of laparoscopic cholecystectomy, and to study the effectiveness of a virtual reality surgical skills simulator as a tool for surgical training and as a method for recording psychomotor behavior. This report describes the purpose of the study, its design, initial results, and implications for the field of medical education.

Cholecystectomy, Laparoscopic↗
PubMed1994

Substance abuse among patients with treatment-resistant schizophrenia: characteristics and implications for clozapine therapy.

OBJECTIVE: The goals of this study were 1) to determine the extent of substance abuse in patients with treatment-resistant schizophrenia and 2) to assess the relevance of such abuse to subsequent response to treatment with clozapine. METHOD: The subjects were 118 treatment-resistant patients with DSM-III-R diagnoses of schizophrenia or schizoaffective disorder who underwent detailed demographic, clinical, and psychopathological evaluations before commencing treatment with clozapine. Lifetime and current histories of substance abuse were also systematically evaluated and characterized according to the Research Diagnostic Criteria and DSM-III-R. Response to clozapine treatment at 6 months was determined with measures of psychopathology and psychosocial function. RESULTS: An antecedent or current history of substance abuse was determined for 29 patients. Although predominantly male, the abusers did not differ from the nonabusers on other demographic features. The substance abusers actually showed less psychopathology (negative and disorganization symptoms) and better psychosocial functioning at baseline; however, both groups attained similar improvements on these measures after 6 months of clozapine therapy. CONCLUSIONS: A modest extent of previous or current substance abuse was observed among neuroleptic-resistant schizophrenic patients who subsequently received treatment with clozapine. This antecedent history of substance abuse did not appear to negatively influence subsequent response to clozapine treatment.

Adult↗
PubMed1994

Substance abuse and clozapine treatment.

Among 118 patients with DSM-III-R diagnoses of schizophrenia or schizoaffective disorder who received treatment with clozapine, 29 patients had an antecedent or current history of substance abuse. Substance abusers and nonabusers showed similar improvements on measures of psychopathology and psychosocial functioning after 6 months of clozapine therapy. The implications of this finding are discussed.

Adult↗
PubMed1993

Thoracoscopic esophageal myotomy in the treatment of achalasia.

We treated 24 patients with achalasia using thoracoscopic (22 patients) or laparoscopic (2 patients) esophagomyotomy. The only operative complications were mucosal lacerations, which occurred in 3 patients and required conversion to an open procedure in 2. Twenty-two (91%) patients were eating by the second postoperative day. Analgesics were only required for the management of pain from the chest tube, which remained in place for a median time of 24 hours. The median postoperative hospital stay was 3 days (range, 20 to 14 days). The myotomy proved to be incomplete in the first 3 patients, who required a second myotomy; this was done laparoscopically in 2. One patient had a paraesophageal hernia repaired 6 months after the myotomy, and 1 patient required an esophagectomy 1 year after the myotomy for a large nonfunctioning esophagus. Late follow-up showed that swallowing was excellent in 17 (71%) and fair to good in 4 (17%). Sixteen (66%) of these 24 patients have regained their original weight. Thus, excellent to good results were ultimately obtained in nearly 90% of the patients. These results suggest that esophageal myotomy performed using minimally invasive techniques appears to be the treatment of choice for achalasia.

Esophageal Achalasia↗
PubMed1993

Cost effectiveness of clozapine in neuroleptic-resistant schizophrenia.

OBJECTIVE: The goal of this study was to determine whether clozapine is a cost-effective treatment for treatment-resistant schizophrenia. METHOD: Data were collected on 96 treatment-resistant patients with schizophrenia for 2 years before they entered a clozapine treatment study and for at least 2 years after they entered the study. Information about the cost of inpatient and outpatient treatment, housing costs, other costs, and family burden through direct interview or questionnaire of these patients and their families were available for 47 of the 96 patients. Data on lost income and Social Security disability insurance were also obtained. Outcome measures included psychopathology, quality of life, global functioning, work function, and rehospitalization. RESULTS: The cost of treatment was significantly decreased in the patients who continued clozapine treatment for at least 2 years. This was primarily due to a dramatic decrease in the frequency and cost of rehospitalization. Costs were nonsignificantly lower in patients who dropped out of treatment. The estimated total 2-year cost for the 59 patients who continued clozapine treatment, the 34 patients who dropped out, and the three who interrupted treatment decreased from $7,390,206 to $5,719,463, a savings of $8,702/year per patient. There was a decrease in total costs of $22,936/year for the 37 patients who continued clozapine treatment for whom cost data were available. There were no significant changes in lost income or Social Security disability insurance payments in either group. Clozapine produced a marked improvement in Brief Psychiatric Rating Scale total scores as well as positive negative symptom scores, Global Assessment Scale scores, Quality of Life Scale scores, work functioning, capacity for independent living, and rehospitalization rates. CONCLUSIONS: Clozapine is a cost-effective treatment for treatment-resistant schizophrenic patients. Cost savings result almost exclusively from the reduced cost of hospitalization.

Adult↗
PubMed1993

Relationship between clinical efficacy and clozapine concentrations in plasma in schizophrenia: effect of smoking.

Concentrations in plasma of clozapine and norclozapine, the major metabolite of clozapine, were measured in 59 treatment-resistant schizophrenic patients at a random time period during the course of treatment. A lower sum of the concentrations of clozapine and norclozapine or either alone predicted less improvement in the Brief Psychiatric Rating Scale (BPRS) Total and Positive symptoms in a multivariate analysis that controlled for baseline BPRS rating and dose. The mean doses of clozapine after 6 months of treatment and at the time of blood sampling were not significantly different in 30 responders and 29 nonresponders to clozapine, on the basis of the decrease in BPRS Total scores, whereas the concentrations in plasma in clozapine of norclozapine and the sum of their concentrations were significantly higher in responders. Clozapine and norclozapine concentrations in plasma correlated both with dose at the time of sampling and with dose at 6 months. A clozapine concentration of 370 ng/ml was the optimal cutoff for distinguishing responders from nonresponders. Clozapine and norclozapine concentrations did not differ in male smokers and nonsmokers.

Adult↗
PubMed1992

Thoracoscopic esophagomyotomy. Initial experience with a new approach for the treatment of achalasia.

The authors treated 17 patients with achalasia by a thoracoscopic (15 patients) or laparoscopic (2 patients) Heller myotomy. All patients had dysphagia and an upper gastrointestinal series demonstrating a dilated esophagus with a bird-beak deformity at the cardia. Manometry showed a mean lower esophageal sphincter (LES) pressure of 32 +/- 4 mmHg, incomplete sphincter relaxation on swallowing, and no primary esophageal peristalsis. After operation, mean LES pressure was 10 +/- 2 mmHg. Fifteen patients were fed on the second postoperative day. The average hospital stay was 3 days, and there were no deaths or major complications. In three early patients, the myotomy was not carried far enough onto the stomach, and dysphagia persisted until a second myotomy was performed (laparoscopically in two patients). The authors found that having an endoscope in the esophagus during the operation facilitated exposure and was vital to determine the appropriate length of the myotomy. With regard to dysphagia, final results were excellent in 12 patients (70%), good in two patients (12%), fair in two patients (12%), and poor in one patient (6%). Heller myotomy can be safely and reliably performed with minimally invasive techniques. Dysphagia is relieved, postoperative pain is minimal, hospital stay is short, and the patient can return quickly to normal activity.

Adult↗
PubMed1984

Variations in concentrating function of the gallbladder in the conscious monkey.

Hepatic bile is concentrated in the gallbladder by absorption of water and electrolytes. The rate of water absorption can be influenced in vitro and in vivo by gastrointestinal hormones and neurogenic transmitters. Recent studies have demonstrated that besides its absorbing activity, the gallbladder has the ability to secrete fluid into its lumen. In the present experiments, we studied the rate of net water absorption in the gallbladders of pig-tailed monkeys sitting in restraining chairs. Bile from the common bile duct and the gallbladder was led out through cannulas to a stream splitter, samples were obtained, and bile was returned to the duodenum. By measuring outflow from the gallbladder and the concentration of bile acids in hepatic bile and bile that had passed through the gallbladder, net water absorption from the gallbladder bile could be calculated. The results demonstrate that during daytime fasting there was a net absorption corresponding to 30% of the fasting gallbladder volume per hour, and after feeding there was a net secretion of fluid into the gallbladder lumen. Compared with the awake fasting state, net water absorption from the gallbladder decreased at night while the animal was fasting and asleep. Physiologically, secretion of fluid after a meal could help to empty the gallbladder, and changes in net water absorption by the gallbladder could influence the kinetics of the enterohepatic circulation of bile acids.

Absorption↗
PubMed1983

Computed tomography and nuclear magnetic resonance imaging of pancreatic islet cell tumors.

Eleven patients with pancreatic islet cell tumors smaller than 2.5 cm were examined by use of computed tomography (CT) and new scanning protocol. Seven of 11 tumors were localized and CT accurately assessed multiple lesions, retroperitoneal invasion, or liver metastases when present. CT is now the initial imaging procedure of choice for diagnosis and staging of islet cell tumors. Nuclear magnetic resonance can distinguish islet cell tumors from normal retroperitoneal structures and appears to be a promising new pancreatic imaging modality.

Adenoma, Islet Cell↗
PubMed1981

Sludge is calcium bilirubinate associated with bile stasis.

Biliary sludge is a frequent finding on abdominal sonography. It is most often found after prolonged stasis of gallbladder bile associated with other illness or mechanical obstruction of the common duct, and seldom indicates primary gallbladder disease. In most cases, sludge is a suspension of pigment precipitates in bile, and is at least in part calcium bilirubinate. Sludge may disappear with the return of normal gallbladder contractility. The ease with which this precipitate forms during stasis of gallbladder bile suggests a role for this process in the pathogenesis of cholelithiasis.

Bile↗
PubMed1978

Increased production of triglyceride-rich lipoproteins after partial biliary diversion in the rhesus monkey.

An interrelationship between bile acid and triglyceride metabolism is suggested by observations in patients with endogenous hypertriglyceridemia and in subjects treated with bile acid-binding resins or chenodeoxycholic acid. We investigated this possible interrelationship in the rhesus monkey. The effect of 14 days of partial bile diversion on plasma concentration and secretion rates of triglyceride-rich lipoproteins was studied by means of a stream-splitting device that permitted controlled interruption of the enterohepatic circulation. Diversion of 25% of the enterohepatic circulation resulted in increased bile acid synthesis and decreased bile acid secretion and pool size, and was associated with a 75% increase in fasting serum triglyceride concentration and a twofold increase in the rate of secretion of triglyceride-rich lipoproteins into plasma. Intraduodenal replacemtn of cholic acid during the period of bile diversion completely prevented the increase in lipoprotein secretion and partially prevented the increase in fasting plasma triglycerides, suggesting that these changes resulted from loss of bile acid rather than other components of bile. These studies show that partial removal of bile acids from the enterohepatic circulation augments the secretion of triglyceride-rich lipoprotein into plasma in the rhesus monkey. Elucidation of the mechanism of this effect may provide important new information concerning the control of hepatic lipoprotein secretion.

Animals↗
PubMed1974

Ulcer disease, metabolic alkalosis and hyperparathyroidism: A mechanism of interrelationship?

In both normal volunteers and in patients with primary hyperparathyroidism, the induction of a metabolic alkalosis by infusion of sodium bicarbonate results in a decrease in serum calcium ion and in an increase of circulating parathyroid hormone concentrations. Bicarbonate infusion may serve in man as a new provocative test for release of parathyroid hormone. Furthermore, we speculate that the metabolic alkalosis which is found at times in patients with the Zollinger-Ellison syndrome and severe peptic ulcer disease may result in parathyroid gland stimulation.

Adult↗