Progressive slippage after pinning for slipped capital femoral epiphysis

The authors retrospectively reviewed seven cases of progressive slipped capital femoral epiphysis after screw fixation. All seven patients initially presented with chronic symptoms, and five had an acute exacerbation of symptoms with the appearance of an acute-on-chronic slip. Of the other two, one had obvious motion at the proximal femoral physis and the other had increased symptoms but did not have an obvious acute slip radiographically. All underwent percutaneous screw fixation. In four patients a single screw was placed, and in three patients two screws were placed. No patient became symptom-free after surgery. Slip progression was noted on average 5 months after treatment. Radiographs in all patients revealed an increase in slip severity and loss of screw purchase in the femoral neck while fixation in the proximal femoral epiphysis remained secure. One patient had hypothyroidism and another Cushing disease, both diagnosed after the slipped epiphysis. Slips occurring in children with underlying endocrinopathies, and unstable slips in children with a history of antecedent knee or hip pain (commonly called an acute-on-chronic slip) may be susceptible to screw fixation failure. In such patients, close radiographic follow-up, particularly in the presence of continued symptoms, is required to document slip progression and fixation failure as soon as possible.     

Evaluation of the Tg.AC transgenic mouse assay for testing the human carcinogenic potential of pharmaceuticals--practical pointers, mechanistic clues, and new questions

Transgenic mouse strains with genetic alterations known to play a role in the multistage process of carcinogenesis are being used increasingly as models for evaluating the human carcinogenic potential of chemicals and pharmaceuticals. The Tg.AC transgenic mouse is one of the strains currently being used in such alternative short-term carcinogenicity testing protocols. This review is focused on recent data from studies designed to evaluate this model's ability to discriminate carcinogens from noncarcinogens. Details relating to protocol design that can significantly impact study outcome are described. Data relating to mechanisms of chemical tumor induction in the Tg.AC model are reviewed, and questions have been formulated to encourage research to further guide appropriate future applications of this model.     

Determination of eight trichothecene mycotoxins using GCMSMS methods. I. elaboration of MS/MS conditions

Trichothecene mycotoxins are commonly distributed in cereals in the world. Rapid and accurate methods for the determination of these toxins are required to prevent the intoxication of human and to contribute to the supply of safe foods and feed. MSMS mode was applied for identification of eight trichothecene mycotoxins with Finnigan/Mat GCQ GC/MS system. We describe here optimal parameters of CID and to obtain best pairs of ions (precursor ions and daughter ions) for all analysed toxins.     

Oxidative stress and neutrophil activation--the two keystones of ischemia/reperfusion injury

The widespread introduction of fibrinolytics and recently also PTCA in the treatment of myocardial infarction has changed the picture of modern cardiology. But this therapy also raises new problems and challenges. One of them is the occurrence of extensive tissue injury caused by reperfusion. Reinstitution of oxygen to the ischemic tissues initiates various processes leading to generation of reactive oxygen species (ROSs). Acting on the plasma membrane ROS damage its organization and release various proinflammatory agents. Different proteins, including receptors, ionic channels, transporters or components of transduction pathways are substrates of oxidation by ROSs. Their changed structure results in altered functioning and disruption of vital cellular processes. Another key factor of reperfusion injury is activation and infiltration of infarcted area by polymorphonuclear leukocytes (PMNs). Multiple studies identified consecutive stages of PMN activation and substances being involved in it. Main interest lies in cellular adhesion molecules, particularly selectins and beta2 integrins, as their antagonists were repeatedly found to diminish neutrophil activation and infarct size. Nevertheless new publications strike at the foundations of the established order and confront the relation between neutrophil infiltration and infarct size. PMNs are linked by close ties to other cells involved in inflammatory response. Seemingly also in cardiac ischemia-reperfusion injury, the activity of neutrophils is modulated by lymphocytes and macrophages. The article describes mutual interactions between different factors involved in the reperfusion injury that may enable preparing new treatments, hopefully as effective and successful as reperfusion therapy.     

Leadership and team effectiveness in community coalitions for the prevention of alcohol and other drug abuse

Comprehensive community coalitions or partnerships are increasinglybeing developed in this country to coordinate and expand alcoholand other drug (AOD) abuse prevention services. While case studyevidence suggests that some coalitions are effective, thereis very little theory development or empirical research on factorscontributing to successful coalitions. This paper presents atheoretical model of coalition team effectiveness hypothesizingthat an empowering style of leadership increases member satisfactionand perceptions of team efficacy which ultimately increasesteam effectiveness. This theoretical model was pilot testedin an exploratory study using preliminary, small sample data(N = 65) from the first year evaluation of an AOD preventioncoalition. The exploratory research strategy employed factoranalysis and multiple regression analysis to test the relationshipof coalition members' process data (i.e. perceptions of teamleader's style, team efficacy and member satisfaction) to outcomedata (i.e. team members' AOD knowledge and use and team effectivenessin developing fundable plans). The results supported the proposedmodel and suggest that further model testing employing largersamples, more diverse community teams, and more sophisticateddata analyses (structural equation modeling or path analysis)could lead to information useful in training team leaders anddeveloping more effective coalitions.