When Too Much Is Not Enough: Obsessive-Compulsive Disorder as a Pathology of Stopping, Rather than Starting

Background: In obsessive-compulsive disorder (OCD), individuals feel compelled to repeatedly perform security-related behaviors, even though these behaviours seem excessive and unwarranted to them. The present research investigated two alternative ways of explaining such behavior: (1) a dysfunction of activation—a starting problem—in which the level of excitation in response to stimuli suggesting potential danger is abnormally strong; versus (2) a dysfunction of termination— a stopping problem—in which the satiety-like process for shutting down security-related thoughts and actions is abnormally weak. Method: In two experiments, 70 patients with OCD (57 with washing compulsions, 13 with checking compulsions) and 72 controls were exposed to contamination cues—immersing a hand in wet diapers —and later allowed to wash their hands, first limited to 30 s and then for as long as desired. The intensity of activation of security motivation was measured objectively by change in respiratory sinus arrythmia. Subjective ratings (e.g., contamination) and behavioral measures (e.g., duration of hand washing) were also collected. Results: Compared to controls, OCD patients with washing compulsions did not differ significantly in their levels of initial activation to the threat of contamination; however, they were significantly less able to reduce this activation by engaging in the corrective behavior of hand-washing. Further, the deactivating effect of hand-washing in OCD patients with checkin

Bone turnover markers for early detection of fracture healing disturbances: A review of the scientific literature

Imaging techniques are the standard method for assessment of fracture healing processes. However, these methods are perhaps not entirely reliable for early detection of complications, the most frequent of these being delayed union and non-union. A prompt diagnosis of such disorders could prevent prolonged patient distress and disability. Efforts should be directed towards the development of new technologies for improving accuracy in diagnosing complications following bone fractures. The variation in the levels of bone turnover markers (BTMs) have been assessed with regard to there ability to predict impaired fracture healing at an early stage, nevertheless the conclusions of some studies are not consensual. In this article the authors have revised the potential of BTMs as early predictors of prognosis in adult patients presenting traumatic bone fractures but who did not suffer from osteopenia or postmenopausal osteoporosis. The available information from the different studies performed in this field was systematized in order to highlight the most promising BTMs for the assessment of fracture healing outcome.As técnicas imagiológicas são o método convencional para a avaliação dos processos de cicatrização das fraturas. No entanto, estes métodos não são talvez totalmente confiáveis para a deteção precoce de complicações, as mais frequentes destas sendo o atraso da união e a não-união. Um diagnóstico eficaz destas desordens poderia prevenir a dor e a incapacidade prolongada do paciente. Esforços devem ser dirigidos no sentido do desenvolvimento de novas tecnologias para melhorar a exatidão no diagnóstico de complicações após fraturas ósseas. A variação nos níveis dos marcadores do turnover ósseo (BTMs) têm sido avaliados com vista à sua capacidade para prever o comprometimento da cicatrização das fraturas numa fase inicial, no entanto, as conclusões de alguns estudos não são consensuais. Neste artigo os autores fizeram uma revisão do potencial dos BTMs como fatores de previsibilidade precoce do prognóstico em doentes adultos que apresentavam fraturas ósseas traumáticas mas que não sofriam de osteopenia ou osteoporose pós-menopausa. A informação disponível nos diferentes estudos realizados neste campo foi sistematizada com vista a evidenciar-se os BTMs mais promissores para a avaliação da evolução da cicatrização das fraturas.SFRH/BD/45018/200

A systematic review of the reporting of Data Monitoring Committees' roles, interim analysis and early termination in pediatric clinical trials

<p>Abstract</p> <p>Background</p> <p>Decisions about interim analysis and early stopping of clinical trials, as based on recommendations of Data Monitoring Committees (DMCs), have far reaching consequences for the scientific validity and clinical impact of a trial. Our aim was to evaluate the frequency and quality of the reporting on DMC composition and roles, interim analysis and early termination in pediatric trials.</p> <p>Methods</p> <p>We conducted a systematic review of randomized controlled clinical trials published from 2005 to 2007 in a sample of four general and four pediatric journals. We used full-text databases to identify trials which reported on DMCs, interim analysis or early termination, and included children or adolescents. Information was extracted on general trial characteristics, risk of bias, and a set of parameters regarding DMC composition and roles, interim analysis and early termination.</p> <p>Results</p> <p>110 of the 648 pediatric trials in this sample (17%) reported on DMC or interim analysis or early stopping, and were included; 68 from general and 42 from pediatric journals. The presence of DMCs was reported in 89 of the 110 included trials (81%); 62 papers, including 46 of the 89 that reported on DMCs (52%), also presented information about interim analysis. No paper adequately reported all DMC parameters, and nine (15%) reported all interim analysis details. Of 32 trials which terminated early, 22 (69%) did not report predefined stopping guidelines and 15 (47%) did not provide information on statistical monitoring methods.</p> <p>Conclusions</p> <p>Reporting on DMC composition and roles, on interim analysis results and on early termination of pediatric trials is incomplete and heterogeneous. We propose a minimal set of reporting parameters that will allow the reader to assess the validity of trial results.</p

Direct measurement of anharmonic decay channels of a coherent phonon

We report channel-resolved measurements of the anharmonic coupling of the coherent A1g phonon in photoexcited bismuth to pairs of high wave vector acoustic phonons. The decay of a coherent phonon can be understood as a parametric resonance process whereby the atomic displacement periodically modulates the frequency of a broad continuum of modes. This coupling drives temporal oscillations in the phonon mean-square displacements at the A1g frequency that are observed across the Brillouin zone by femtosecond x-ray diffuse scattering. We extract anharmonic coupling constants between the A1g and several representative decay channels that are within an order of magnitude of density functional perturbation theory calculations