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K J Levin

Publications and source records attributed to K J Levin.

13 recordsLinked to original sources
PubMed1999

Use of the RTOG recursive partitioning analysis to validate the benefit of iodine-125 implants in the primary treatment of malignant gliomas.

PURPOSE: To date, numerous retrospective studies have suggested that the addition of brachytherapy to the conventional treatment of malignant gliomas (MG) (surgical resection followed by radiotherapy +/- chemotherapy) leads to improvements in survival. Two randomized trials have suggested either a positive or no survival benefit with implants. Critics of retrospective reports have suggested that the improvement in patient survival is due to selection bias. A recursive analysis by the RTOG of MG trials has stratified MG patients into 6 prognostically significant classes. We used the RTOG criteria to analyze the implant data at Wayne State University to determine the impact of selection bias. METHODS AND MATERIALS: Between July 1991 and January 1998, 75 patients were treated with a combination of surgery, radiotherapy, and stereotactic I-125 implant as primary MG management. Forty-one (54.7%) were male; 34 (45.3%) female. Median age was 52 years (range 4-79). Twenty-two (29.3%) had anaplastic astrocytoma (AA); 53 (70.7%), glioblastoma multiforme (GBM). Seventy-two patients had data making them eligible for stratification into the 6 RTOG prognostic classes (I-VI). Median Karnofsky performance status (KPS) was 90 (range 50-100). There were 14, 0, 14, 31, 12, and 1 patients in Classes I to VI, respectively. Median follow-up time for AA, GBM, and any surviving patient was 29, 12.5, and 35 months, respectively. RESULTS: At analysis, 29 (40.3%) patients were alive; 43 (59.7%), dead. For AA and GBM patients, 2-year and median survivals were: 58% and 40%; 38 and 17 months, respectively. For analysis purposes, Classes I and II, V and VI were merged. By class, the 2-year survival for implanted patients compared to the RTOG data base was: III--68% vs. I--76%; III--74% vs. 35%; IV--34% vs. 15%; V/VI--29% vs. V--6%. For implant patients, median survival by class was (in months): I/II--37; III--31; IV--16; V/VI--11. CONCLUSION: When applied to MG patients receiving permanent I-125 implant, the criteria of the RTOG recursive partitioning analysis are a valid tool to define prognostically distinct survival groups. As reflected in the RTOG study, a downward survival trend for the implant patients is seen from "best to worse" class patients. Compared to the RTOG database, median survival achieved by the addition of implant is improved most demonstrably for the poorer prognostic classes. This would suggest that selection bias alone does not account for the survival benefit seen with I-125 implant and would contradict the notion that the patients most eligible for implant are those gaining the most benefit from the treatment. In light of the contradictory results from two randomized studies and given the present results, further randomized studies with effective stratification are required since the evidence for a survival benefit with brachytherapy (as seen in retrospective studies) is substantial.

Adolescent↗
PubMed1993

Lipid peroxidation does not appear to be a factor in late radiation injury of the cervical spinal cord of rats.

PURPOSE: We tested the role of lipid peroxidation in the demyelination and white matter necrosis associated with radiation injury of the central nervous system. METHODS AND MATERIALS: We irradiated the cervical spinal cords of female F344 rats (23 Gy) and assayed for the accumulation of the peroxidation byproducts malondialdehyde and hydroxyeicosatetraenoic acids, and for the consumption of the endogenous free radical scavengers vitamins E and C. We further tested the role of lipid peroxidation in radiation injury of the central nervous system by determining the sensitivity of the cervical spinal cord to radiation in rats on diets containing deficient, normal, and supplemental levels of the antioxidant vitamin E. Rats were placed on these diets at 4 weeks of age and irradiated (18.5-21.5 Gy) 16 weeks later. RESULTS: During the 5 months between irradiation and the onset of paralysis, no accumulation of peroxidation byproducts or consumption of endogenous scavengers was seen in the cervical spinal cords of the irradiated rats. The cervical spinal cords of some of the rats placed on the diets with deficient, normal, and supplemental levels of vitamin E were analyzed at the time of irradiation and contained 197 +/- 57, 501 +/- 19, and 717 +/- 35 pmol vitamin E/mg protein, respectively. Despite the statistical differences in these levels, the radiation sensitivity of the cervical spinal cord (ED50 for white matter necrosis) in rats receiving the three diets was not different (20.4, 20.7, and 20.6 Gy). CONCLUSION: These data do not support a role for free radical-induced lipid peroxidation in the white matter damage seen in radiation injury of the central nervous system.

Animals↗
PubMed1990

Polyamine accumulation and vasogenic oedema in the genesis of late delayed radiation injury of the central nervous system (CNS).

Polyamine (PA) accumulation has been associated with blood-brain barrier (BBB) disruption and vasogenic oedema after cold injury. PAs and water content were measured in a rat spinal cord model of late-delayed radiation injury and were found to be elevated at paralysis. The elevated PA levels could be significantly reduced by treatment with difluoromethylornithine (DFMO). In unirradiated rats DFMO reduced putrescine to undetectable levels after 10-12 weeks. These data suggest that blockade of PA synthesis may be useful in treating the vasogenic oedema of radiation injury and may improve CNS radiation tolerance.

Animals↗
PubMed1989

Procedural skills.

Explore the source record for details and available documents.

Anesthesiology↗
PubMed1983

Medical student education in life-support skills.

A life-support skills course designed to facilitate competent decision making during emergency care situations has been developed for third-year medical students at the University of North Carolina at Chapel Hill School of Medicine. The objective of the one-week course is to combine the knowledge acquired in the basic sciences with the performance skills required in the clinical setting. This is achieved through the use of a variety of instructional strategies, including lectures, reading periods, and laboratory exercises. A scientific approach to the teaching of life-support skills is incorporated, educational objectives are defined, methods of achieving the educational objectives are provided, and an evaluation system is used to determine the effectiveness of teaching. After successful completion of the training program, the student is better able to deliver competent emergency medical care.

Clinical Competence↗
PubMed1976

Ambulatory surgery in a university setting.

Establishment of an ambulatory anesthesia and surgery program in a university teaching hospital presents difficulties. A successful program of this nature, the "Day Op program," was begun at the North Carolina Memorial Hospital in December 1972. Through December 1974, of all surgery performed in our operating rooms, 2,590 cases, (17%) were Day Op cases. Various types of anesthesia were used, and a high percentage of endotracheal intubations were performed. The hospital admission rate was 1.54%. Many difficulties were encountered, and much satisfaction was obtained, in the management of the program. The Day Op room has proved to be a major part of the success of the program.

Adult↗
PubMed1976

Cardiorespiratory effects of a balanced anesthetic technique in outpatient general anesthesia.

Detailed measures have been made of the cardiorespiratory effects of a balanced general anesthetic technique on ten young patients undergoing oral surgery. The combination of fentanyl, diazepam, and atropine followed by N2O/O2 and methohexital resulted in a respiratory hyperoxic state throughout surgery and there was no evidence of hypercardia at any anesthesia stage. Cardiovascular stability was judged to be generally superior to that reported for techniques that have relied on methohexital without premedication. This balanced general anesthetic technique offers the oral surgeon-anesthetist a safe, effective, and practical alternative to techniques that rely on more potent anesthetic gases.

Adult↗
PubMedDate not supplied

Cardiovascular effects of cannabinol during oral surgery.

Fifty-five clinical trials were conducted to determine the cardiovascular combined effects of stressful oral surgery and systemic cannabinols. In a first study, delta9-tetrahydrocannabinol (THC) was given IV as a premedicant and compared with diazepam and with a placebo. A classic dose-related tachycardia followed THC injection. The peak heart rate response of patients premedicated with 0.044 mg/kg THC was 24.1% higher (p less than 0.05) than the peak effect for a nonsurgerized control group, suggesting a synergistic effect between THC and surgical stress. A predisposition to syncopal hypotension followed THC premedication, and antiarrhythmic effects were observed after large doses. The injection of local anesthetic preparations containing epinephrine did not alter THC cardiovascular response. An apparent drug interaction was observed, however, in a second study, in patients given general anesthesia within 72 hours after smoking marijuana. These patients demonstrated sustained abnormal postoperative tachycardia when compared with control nonsmokers, an effect which may have resulted from an interaction between stored cannabinol metabolites and atropine administered as part of the anesthetic technic. It was concluded that THC had no particular advantage over diazepam or placebo as a premedicant. Further, THC altered the patients' adaptivity to stress and interacted undesirably with other anesthetic medications.

Adult↗
PubMedDate not supplied

Fatal hepatic necrosis after halothane anesthesia in a boy with juvenile rheumatoid arthritis: a case report.

Hepatitis from halothane is usually diagnosed by excluding other possible causes. Whether preexisting hepatic damage, which can occur in certain autoimmune disorders, contraindicates the use of halothane has yet to be proven. The case of a 14-year-old boy with early-onset juvenile rheumatoid arthritis who developed fatal hepatic necrosis 13 days after halothane anesthesia is presented.

Adolescent↗
PubMedDate not supplied

Anesthesiology and the graduating medical student: a national survey.

Each year, many anesthesiology housestaff positions remain vacant or are filled by foreign medical graduates. While possibly reflecting an overabundance of such housestaff positions, this situation also suggests a lack of U.S. student interest in anesthesiology. To investigate this phenomenon, the authors conducted a survey of American medical school graduates of 1976. The results reveal that 65% of students receive minimal or no systematic exposure to anesthesiology or anesthesiologists. When such exposure occurs, it comes after many students have developed strong specialty preferences. Many students saw anesthesiology as limited in scope and unchallenging and indicated that they did not select anesthesiology because it entails insufficient primary patient care. Contrasts between those entering and not entering anesthesiology suggest, however, that certain variables which are subject to manipulation--such as amount, timing, and content of exposure to anesthesiology--could alter student attitudes and potentially generate increased student interest in the specialty.

Anesthesiology↗