Cannabis use correlates with schizotypal personality traits in healthy students

The literature suggests that cannabis use and schizotypal traits both constitute risk factors for the later development of schizophrenia. However, their interrelationships remain to be evaluated. The present study examined the association between cannabis use and schizotypal traits in 232 healthy students who ranged in age from 18 to 25 years. All the students had completed the Schizotypal Personality Questionnaire and four of the Chapman Psychosis Proneness Scales: the Magical Ideation Scale; the Perceptual Aberration Scale; the Revised Physical Anhedonia Scale; and the Revised Social Anhedonia Scale. Subjects were divided into three groups according to cannabis use typology: those who had never used cannabis, those who were past or occasional users, and those who were regular users. Higher scores on the Schizotypal Personality Questionnaire and the Magical Ideation Scale characterized the regular and past or occasional users compared with those who had never used cannabis. The co-occurrence of cannabis use and schizotypal traits appeared to be independent of anxiety and depression dimensions. These data suggest that cannabis use and schizotypal traits have to be jointly considered in further longitudinal studies of schizophrenia risk factors.     

Intercomparison of treatment concepts for MR image assisted brachytherapy of cervical carcinoma based on GYN GEC-ESTRO recommendations.

PURPOSE: To perform a multicentre intercomparison study of treatment concepts for MRI assisted brachytherapy of cervix cancer based on recommendations of the Gynaecological GEC-ESTRO Working Group. METHODS: Each participating centre (IGR Paris, University Hospital Leuven, Medical University of Vienna) contributed data of one patient with comparable clinical features. GTV, High Risk CTV (HR CTV), Intermediate Risk CTV (IR CTV) and organ walls of bladder, rectum and sigmoid colon were delineated at the time of each brachytherapy fraction on axial MR images with the applicator in place. Dose-volume histograms were calculated to evaluate doses to tumour, target volumes and organs at risk. Dose values were biologically normalised to equivalent doses in 2 Gy fractions (EQD(2), equivalent to 50 cGy/h low dose rate) applying the linear-quadratic model. RESULTS: Total doses to point A from external beam therapy plus brachytherapy ranged from 85 to 91 Gy and were close to the dose covering 90% of HR CTV (D90=85-87 Gy). D90 of IR CTV was within 69-73 Gy. Doses to organs at risk were comparable. CONCLUSIONS: This study indicates the feasibility of the GEC-ESTRO recommendations. Despite different treatment concepts, biologically normalised total doses to tumour, target volumes and organs at risk were comparable.     

Metacarpophalangeal prosthesis modeling. Comparison of stress factors in a normal and a prosthetic metacarpophalangeal joint using finite element analysis

INTRODUCTION: Prosthetic replacement of the metacarpophalangeal joints of long fingers is a problematical technique for the surgeon. The aim of the present study was to examine and compare, by means of finite element analysis, stress distribution in a normal metacarpophalangeal joint and to compare this with the findings in a similar joint with a prosthesis in order to better determine the risk of aseptic loosening, and also to examine possible solutions to limit these risks. METHOD: Finite element modelling was carried out using Abaqus software. Various criteria were taken into account including anatomical data, stress distribution, mechanical characteristics of the materials used, and different positions of the phalanx. RESULTS: A comparison of the results showed two significant stress distribution factors, i.e., a reduction of normal stress in the cortical bone of the finger fitted with a prosthesis; and the appearance of a flexion moment which completely modified the stress distribution throughout the metacarpal and therefore also in the opposite phalanx. DISCUSSION: To reduce the risk of aseptic loosening, two solutions were proposed: a) to reduce Young's module. The problem which arises, as in the case of total hip prosthesis, is that of finding a material with a Young's module which is closer to that of cortical bone, and which at the same time has a high elastic limit and breakage point and good biocompatibility; b) to reduce the inertia of the prosthesis, which seems the more likely of the two propositions, as it is based on the results of the modelling. The inertia of the prosthesis on stress distribution can be reduced by modifying two parameters, namely by producing a hollow section and shortening the structure of the prosthesis.     

Physiological anticoagulants and activated protein C resistance in childhood stroke

Immunological and functional protein S, protein C and antithrombin III levels and anticoagulant responses to activated protein C were measured in 24 patients with stroke in childhood. No hereditary deficiencies were found. The protein S levels in healthy controls of younger age did not differ from the adult levels. For optimal screening of protein S deficiency, measurements using functional as well as immunological assays are recommended. Appropriate criteria for the diagnosis of the deficiencies must be carefully applied if unnecessary anxiety and inappropriate treatment of children are to be avoided.     

Evaluation of attempted prevention of unexpected infant death in very high-risk infants by planned health care

Three hundred and ninety-six babies born in Sheffield between 1982 and 1990 identified as being at "very high risk" of unexpected infant death by means of a scoring system, received an intensive programme of health care including a case discussion between a paediatrician, the GP and the health visitor held in the family doctor's surgery, weekly visits from the health visitor and informal hospital admission. Significantly fewer sudden unexpected infant deaths occurred in this group than were expected by logistic regression anlysis or occurred in the best available control group with comparable scores ( p = 0.024). Problems in evaluation include identification of an adequate control population, ethical difficulties in introducing a controlled study when the programme is already perceived as effective, and the calculation of "expected death rates". The results of this study indicate that very energetic programmes of intervention may prevent some deaths in vulnerable infants.     

Fibromatosis of bone in children

Radiographs, computed tomograms, and radionuclide bone scans were obtained preoperatively in three children with fibromatosis involving the bones and soft tissues of the extremities. Two of the children had identical scar-like bone lesions of the proximal tibia, which, to the authors' knowledge, have not been reported before in this disease. The lesions recurred in two children.     

Study of central motor pathways using cortical magnetic stimulation and spinal electrical stimulation: results in 20 normal subjects

Evoked motor potentials can be elicited by magnetic cortical or electric spinal stimulations. The central conduction time (CCT) corresponds to the difference in latencies between the total conduction time (from cortex to muscle) and the peripheral conduction time (from spinal cord to muscle). CCT is the sum of the conduction time in the cortico-spinal fibers, of the spinal synaptic delay, and of the conduction time in the proximal part of the motor roots. CCT values (mean + standard deviation) were determined in 20 healthy subjects ranging from 21 to 56 years of age (mean 31.2). Results of magnetic cortical stimulation were compared to the results of electrical stimulation of the cortex. CCTs after magnetic cortical stimulation were longer than CCTs after electric cortical stimulation. This could be explained by the fact that electrical stimulation elicits a direct response in the cortico-spinal tract whereas magnetic cortical stimulation has indirect effects on the pyramidal cells of the motor cortex through excitatory interneurons. Compared with electrical stimulation, the magnetic stimulation has the great advantage of being painless and allows a safe evaluation of the central motor pathways in man.