[Patient dose: implementation of a clinical practice assessment in medical imaging]. / La dosimétrie patient: exemple d'une démarche d'évaluation des pratiques en imagerie médicale.

PURPOSE: To describe our experience with the implementation of a clinical practice assessment (CPA) with regards to radiation exposure in CT. METHODS: Such a CPA requires that a reference level be available (DRL: diagnostic reference level) along with exposure data (CTDIvol and DLP) allowing for the evaluation of current practices, development of an action plan for improvement and future follow-up after implementation. RESULTS: The action plan for improvements was elaborated based on the review of 641 radiation exposure data points collected over 1 year (CTDIvol and DLP). These data were compared to DRL values of corresponding anatomical regions. The implementation of dose guidelines enabled continuous quality improvement as opposed to punctual radiation dose assessments. CONCLUSION: The requirement of recording patient exposure was an excellent opportunity to perform a CPA activity as described by the Haute Autorité de Santé (HAS) in its clinical audit process.

A housekeeper with power of attorney: the rRNA genes in ribosome biogenesis.

Ribosome biogenesis centres both physically and functionally on the activity of the ribosomal RNA (rRNA) genes. Ribosome assembly occurs co-transcriptionally on these genes, requires the coordinated expression and assembly of many hundreds of proteins and is finely tuned to cell and organism growth. This review presents contemporary understanding of the mode and the means of rRNA gene transcription and how growth factors, oncogenes and tumour suppressors regulate this transcription. It is argued that transcription elongation is a key mechanism regulating rRNA gene transcription. This unorthodox view provides a logical framework to explain the co-transcriptional phase of ribosome biogenesis.

A new paradigm for the regulation of the mammalian ribosomal RNA genes.

Ribosome assembly occurs co-transcriptionally on the rRNA genes. This process requires the co-ordinated expression and assembly of many hundreds of proteins and is finely tuned to cell and organism growth. Co-ordinate regulation of the rRNA genes and the ribosomal protein genes is therefore essential for high-fidelity ribosome assembly. Recent work shows that rRNA gene transcription is regulated at the level of elongation via the mitogen-activated protein kinase pathway. We argue that this may provide an explanation for the high fidelity of ribosome assembly.

Trochanteric slide osteotomy in revision total hip arthroplasty for loosening.

We used a trochanteric slide osteotomy (TSO) in 94 consecutive revision total hip arthroplasties (90 with replacement of both the cup and stem). This technique proved to be adequate for removing the components, with few complications (two minor fractures), and for implanting acetabular allografts (18%) and reinforcement devices (23%). Trochanteric union was obtained in most patients (96%), even in those with septic loosening (18/19), major femoral osteolysis (32/32), or previous trochanteric osteotomy (17/18). TSO is versatile, since it can be extended by a femoral flap (four cases) or a distal femoral window (eight cases). Despite significant bone loss, in 24% of the femora and 57% of the acetabula, favourable midterm results were achieved and only six reoperations were required, Including two for trochanteric nonunion and two for loosening. It leaves the lateral femoral cortex intact so that a stem longer than 200 mm was needed in only 25% of patients. This is a considerable advantage compared with the extended trochanteric osteotomy in which the long lateral flap (12 to 14 cm) requires an average length of stem of 220 mm beyond the calcar. TSO provides an approach similar in size to the standard trochanteric osteotomy but with a rate of nonunion of 4% versus 15%. It reduces the risk of difficulties with removal of the stem, and removes the need for routine distal anchoring of long revision stems. The limited distal femoral compromise is very important in patients with a long life expectancy.

[Study of psychometric properties of two new questionnaires assessing beliefs in hypochondriasis in a non-clinical population]. / Evaluation des croyances reliées à la santé. Etude des propriétés psychométriques de deux nouveaux instruments evaluant les croyances présentes dans l'hypocondrie auprés d'une population non clinique.

Most instruments focussing on hypochondriasis symptoms do not have for goal to assess beliefs specifically. Instead, these instruments are used to measure specific behaviors. To assess underlying beliefs with these kinds of instruments, you have to extract false beliefs by deduction. In cognitive therapy, it is important to target erroneous beliefs in order to change them. On the other hand, existing instruments are not really suitable to target erroneous health beliefs. Even if some questionnaires are built to assess beliefs directly, it seems that they only measure the conviction of having an illness and do not assess the general health beliefs present in excessive health worriers. However, many researchers argue that this other kind of beliefs are the ones responsible in maintaining hypochondriasis symptoms. Presently, researchers assume that erroneous beliefs can maintain worries about illness among people with hypochondriasis symptoms like false beliefs about worry maintain worries in people with General Anxiety Disorder (GAD). Even if the importance of false beliefs in the maintenance of pathological worries is now recognized, most instruments on hypochondriasis symptoms do not have for goal to assess erroneous beliefs concerning worry about health. For instance, although the questionnaire Why do people worry? (WW) shows good psychometric properties and measures beliefs related to general worries, this questionnaire is not specific enough to correctly evaluate beliefs associated to health worry. A new questionnaire has to emerge in order to assess false beliefs associated to worry about health. This manuscript presents the development and the validation of a new questionnaire: the General Health Beliefs Questionnaire (GHBQ) that assesses general health beliefs, and also presents the development and the validation of a new questionnaire assessing beliefs associated to worry about health: the Why do people Worry about Health? (WW-H) . In this study, the GHBQ's and the WW-H's psychometric qualities and the factorial structure were assessed. More precisely, this study examined the factorial structure, the temporal stability, the convergent, divergent and criteria validities of the GHBQ and the WW-H. Four hundred and twenty nine French-speaking university students (non-clinical participants) completed a battery of questionnaires at the beginning of a class. The questionnaires were: The General Health Beliefs Questionnaire (GHBQ), the Why do people Worry about Health (WW-H), the Illness Worry Scale (IWS), the Beck Depression Inventory-short form (BDI-short form) and the Beck Anxiety Inventory (BAI). A second administration took place three weeks later with the same sample to test the temporal stability of the GHBQ and the WW-H. The principal component analysis with orthogonal rotation (varimax) supports a five components solution for the GHBQ: 1) magical thinking, 2) health, 3) consequences, 4) responsibility, and 5) vulnerability. The principal component analysis with oblique rotation (direct oblimin) (d=0) found a two components solution for the WW-H: 1) utility and 2) magical thinking associated to worries about health. The internal consistency of the GHBQ and the WW-H is excellent (a=.80 and a=.90, respectively). A correlation of 0.49 was found between the GHBQ and the WW-H. The correlation between the GHBQ and the IWS who evaluates the tendency to worry (r=.50) and between the WW-H and the IWS (r=.49) showed that the convergent validity of these questionnaires is adequate. On a three weeks interval, the GHBQ (r=.70) and the WW-H (r=.71) showed a satisfying temporal stability. The means of the high worriers (80 superior percentile at the IWS) (M=38.8, ET=8.93) and the means of the moderate worriers (between the 40 and the 60 percentile at the IWS) (M=32.8, ET=8.00) on the GHBQ have been compared. A significant difference has been found between the two groups [F(1,181)=23,129, p<0,001]. Also, the means of the high worriers (M=27.3, ET=8.59) and the means of the moderate worriers (M=23.8, ET=8.56) on the WW-H haveave been compared. An ANOVA has found a significant difference between these two groups [F(1,180)=7,396, p=0,007]. These results show that general health beliefs and false beliefs associated to worry about health are more often present in high worriers than in moderate worriers. The GHBQ and the WW-H allow psychologists, physicians and psychiatrists to do a quicker and more exhaustive evaluation of general health beliefs and false beliefs associated to worry about health, in less costs. These questionnaires will improve the chances of success of the hypochondriasis' treatment by helping clinicians to detect and correct false beliefs more easily.

Differences and similarities between obsessive intrusive thoughts and worry in a non-clinical population: study 1.

Worry is the central characteristic of Generalized Anxiety Disorder (GAD) and obsessions are a central feature of Obsessive-Compulsive Disorder (OCD). There are strong similarities between these disorders: repetitive cognitive intrusions, negative emotions, difficulty dismissing the intrusion and finally, loss of mental control. Direct comparisons between obsessions and worries are almost non-existent in the literature but key distinctions have been proposed. The study attempted to specify the differences between obsessive intrusive thoughts and worry in a nonclinical population across a series of variables drawn from current models (appraisal, general descriptors and emotional reactions). 254 students participated in the study. They first identified an obsession-like intrusion and a worry and then evaluated them with the Cognitive Intrusion Questionnaire. Within-subject comparisons demonstrated significant differences on several variables: frequency, duration, percentage of verbal and image content, interference, egodystonic nature, stimuli awareness, emotions, etc. Most of these differences remained significant after controlling for frequency of thought. Discriminant analysis demonstrated a low classification error rate when using nine variables to categorize thoughts as obsessions or worries. Results generally support the differences postulated in the literature with the exception that obsessive intrusive thoughts are better controlled. The egodystonic/egosyntonic dimension emerged as an important variable in understanding obsessions and worry.

Differences and similarities between obsessive intrusive thoughts and worry in a non-clinical population: study 2.

Differences between obsessions and worry have been clearly demonstrated on several variables [Langlois, F., Freeston, M. H., & Ladouccur, R. (2000). Differences and similarities between obsessive intrusive thoughts and worry in a non-clinical population: study 1. Behaviour Research and Therapy, 38, 157-173.]. Previous factor analysis of obsessions or worries have typically been used in developing measures for OCD and GAD symptoms. These studies generally support the distinctiveness of obsessions and worries but there have been no direct comparisons of the factor structure of obsession and worry on the same measure. This study aimed to compare the general structure of worry and obsessional intrusions. It also attempted to identify the relations between the respective factors identified in the appraisals of intrusions and the factor structures of coping strategies used in reaction to the thoughts. 254 students participated in the study. They first identified an obsession-like intrusion and a worry and then evaluated them with the Cognitive Intrusion Questionnaire. Different factor structures were obtained for worry and obsessive intrusive thoughts. However, the factor structure for the strategies used to counter the thoughts were highly similar for both types of thought. Furthermore, regression analysis identified interesting relationships between the strategies, the thought characteristics and appraisal. Thus, despite the ability to find differences between obsessive intrusive thoughts and worry, and even to accurately categorize them based on these differences, there may in fact exist common processes that are shared over much of a continuum. Sharp differences in the processes involved may only become clear in prototypical cases. The implications for models of cognitive intrusion are discussed.

Experimental manipulations of responsibility: an analogue test for models of obsessive-compulsive disorder.

Several authors attribute excessive responsibility a predominant role in Obsessive-Compulsive Disorder (OCD) [Salkovskis, P. M. (1985) Behaviour Research and Therapy, 23, 571-583; Rachman, S. (1993) Behaviour Research and Therapy, 31, 149-154; van Oppen, P. & Arntz, A. (1994) Behaviour Research and Therapy, 32, 79-87]. The present studies aimed at demonstrating the link between different levels of perceived responsibility and checking behaviors by experimentally manipulating responsibility in non-clinical Ss. In the first study, a sound recognition task was used to compare checking behaviors in Ss with high (HR) and low (LR) perceived responsibility. Only one variable was significantly different, Ss from the HR group reporting more anxiety during the task than Ss from the LR group. Results did not support a link between responsibility and checking behavior. In a second study HR and LR Ss were compared on a manual classification task. Subjects from the HR group hesitated and checked more, and reported more preoccupation with errors and anxiety during the task than Ss from the LR group. Since perceived severity of the outcome was the most variable affected by the manipulation, the implications for current models of OCD are discussed and an alternative explanation is attempted. Finally, clinical implications are examined and suggestions are made for future directions of research.

Restoration of the velocity field of the heart from two-dimensional echocardiograms.

A method to quantify the motion of the heart from digitized sequences of two-dimensional echocardiograms (2-D) echos was recently proposed. This method computes on every point of the 2-D echoes, the 2-D apparent velocity vector (or optical flow) which characterizes its interframe motion. However, further analysis is required to determine what part of this motion is due to translation, rotation, contraction, and deformation of the myocardium. A method to locally obtain this information is presented. The proposed method assumes that the interframe velocity field U(xy), V(x,y) can be locally described by linear equations in the form U(x,y)=a+Ax+By; V(x,y)=b+Cx+Dy. The additional constraint was introduced in the computation of the local velocity field by the method of projections onto convex sets. Since this constraint is only valid locally, the myocardium must be first divided into sectors and the velocity fields computed independently for each sector.