Lecithin-protein interaction in the GTP-dependent acyl-CoA synthase

The enzymic activity of the GTP-dependent acyl-CoA synthase isolated from rat liver mitochondria is affected by removal and addition of lecithin (3). Purified preparations of this enzyme contain bound lecithin. In this presentation the nature of the lecithin-protein interaction is examined. From binding measurements at different temperatures it is possible to postulate which type of secondary valence bonds is holding the protein and lecithin together. Presented at AOCS Meeting, Chicago, October 1967.     

Enhancement by hyperthermia of the in vitro cytotoxicity of mitomycin C toward hypoxic tumor cells

Mitomycin C and hyperthermia are both toxic to chronically hypoxic EMT6 tumor cells. Combinations of this drug and heat were tested in vitro in normally aerated and chronically hypoxic EMT6 mouse mammary tumor cells to establish whether greater than additive cytotoxicity could be achieved by combined treatment. Cell survival was measured at four concentrations of mitomycin C (0.01, 0.1, 1.0, and 10 microM) at 37 degrees or at elevated temperatures (41, 42, and 43 degrees) for durations of 1, 2, 3, and 6 hr. At 42 degrees, exposure to mitomycin C for 3 and 6 hr produced a 2- to 3-fold increase in hypoxic tumor cell kill at all drug concentrations over that expected for strict additivity. A 15-fold enhancement in the kill of hypoxic tumor cells was obtained at 1.0 and 10 microM mitomycin C at 43 degrees for 6 hr of exposure. Under most conditions, additivity was observed for the antibiotic and heat in oxygenated cells, except at 43 degrees with 0.01 and 0.1 microM mitomycin C following 3 and 6 hr of treatment, conditions under which a 5- to 10-fold potentiation of tumor cell kill was obtained. The rate of formation of reactive metabolites from mitomycin C under anaerobic conditions in EMT6 cell-free preparations was measured. A 30 to 50% increase in alkylating activity was observed at elevated temperatures, suggesting that the enhanced cytotoxicity of mitomycin C with heat toward hypoxic cells may, in part, be due to an increase in activation of the drug.     

Evaluation of alpine skiing and snowboarding injury in a northeastern state

BACKGROUND: To demonstrate the injury patterns of Alpine skiing and snowboarding in a northeastern state and evaluate potential risk factors. METHODS: The medical records of a single pediatric and adult Level I trauma center were evaluated from January 1, 1990, through December 31, 1995. All admissions with injuries caused by Alpine skiing or snowboarding were reviewed. Those patients arriving from two local ski resorts, all of whose injuries are referred to the institution for care, were separated out for consideration. Age, sex, type of injury, date of injury, Injury Severity Score, operations performed, and outcome (including mortality) were evaluated. In addition, resort utilization for the study period was obtained from the two resorts included in the evaluation. Mortality data was obtained from the Vermont office of the Chief Medical Examiner for the same time period. RESULTS: For the 6-year period of the study approximately 2,978,000 skier and snowboarder days were recorded at the study sites. Approximately 447,000 of those days were attributed to snowboarders (15%). In all, 279 patients were admitted for injuries (0.01%), 238 were related to Alpine skiing (incidence 0.01%) and 40 to snowboarding (incidence 0.01%). Snowboarders were statistically younger (20 years; range, 4-44 years) than skiers (29 years; range, 6-70 years) (p < 0.001) and had a significantly lower Injury Severity Score (15 in snowboarders vs. 27 in skiers, p < 0.03). Two female patients were injured snowboarding and 68 female patients were injured skiing. Eight percent of injured snowboarders and 16% of injured skiers sustained multiple injuries (p < 0.01). Injury patterns were significantly different. Upper extremity injuries were almost exclusively found in snowboarders (24% vs. 7%, p < 0.003), whereas cruciate ligament injuries occurred far more commonly in skiers (45% vs. 4%, p < 0.001 Lower extremity injuries in general were more common in skiers (78% vs. 38%, p < 0.001). Central nervous system injuries, including head and spine, were evenly distributed over the two groups, although the snowboarders with central nervous system injuries were younger. In addition, splenic injuries were more common in snowboarders (13% vs. 2%, p < 0.01). Snowboarding accidents were far more common in December, March, and April than other months. Fifty-one patients sustained abdominal or chest injuries and only two of these required operative intervention (two splenectomies). Other operative interventions were limited to extremity injuries, injuries of the spine, or placement of an intracranial pressure monitor. There were no fatalities recorded in this population, although over the 6.5 years, there were 25 deaths related to alpine skiing and one to snowboarding in the State (incidence 0.0000009 skier days). Victims tended to be male: 96% of the skiers and the one snowboarder. The predominant cause of death was blunt head trauma followed by blunt chest trauma. Helmets were not worn by those sustaining head injuries or fatalities. Spine injuries were recorded only in extremely young snowboarders and skiers out of control. CONCLUSION: Snowboarders and Alpine skiers are equally prone to injury. Snowboarding accidents are typically less severe and show significantly different injury patterns than skiing accidents. Abdominal and chest injuries in this population are generally amenable to nonoperative management. Prevention programs are best targeted at safe skiing and snowboarding practices, not skiing or snowboarding in poor conditions, use of helmets for skiers, and restraint of snowboard use in very young children.