A comparison of Nd:YAG laser damage thresholds for PMMA and silicone intraocular lenses

Power density producing damage at a probability of 0.5 (ie, damage threshold, DT-50) was determined for PMMA (with/without UV absorber) and Silicone intraocular lenses. Scattered light from a collinear diagnostic He:Ne beam was one of four damage monitors deployed to enhance the sensitivity of the system. In order of increasing laser resistance the following results were obtained: injection molded PMMA (1.9/GW/cm2) Silicone (2.63 GW/cm2) Lathe-cut PMMA (4.47 GW/cm2), Lathe-cut PMMA with UV absorber (8.32 GW/cm2), Cast-molded PMMA (12.30 GW/cm2). An analysis of variance revealed interclass differences significant at the .01 level. Cast-molded PMMA was the most laser-resistant IOL material.     

Effectiveness of early orthodontic treatment with the Twin-block appliance: a multicenter, randomized, controlled trial. Part 1: Dental and skeletal effects.

This study evaluated the effectiveness of early orthodontic treatment with the Twin-block appliance for the developing Class II Division 1 malocclusion. This multicenter trial was carried out in the United Kingdom. A total of 174 children, aged 8 to 10 years old, with Class II Division 1 malocclusion were randomly allocated to receive treatment with a Twin-block appliance or to an untreated, control group. Data were collected at the start of the study and 15 months later. Results showed that early treatment with Twin-block appliances resulted in reduction of overjet, correction of molar relationships, and reduction in severity of malocclusion. Most of this correction was due to dentoalveolar change, but some was due to favorable skeletal change. Early treatment with the Twin-block appliance is effective in reducing overjet and severity of malocclusion. The small change in the skeletal relationship might not be considered clinically significant.     

Diagnosing menstrual disorders: a qualitative study of the approach of primary care professionals

BACKGROUND: Menstrual disorders are a common presentation in primary care. Wide variations in management as well as discordance between patient and practitioners in relation to presenting problems have been described. AIMS: To explore the model of menstrual disorders used by practitioners in practice. DESIGN OF STUDY: Semi-structured interviews with primary care practitioners. SETTING: One inner London health authority area. METHOD: Constant comparative analysis. RESULTS: Medical practitioners were critical of the guidance provided by gynaecological definitions and texts. Practitioners put more emphasis on defining normality than on defining disorder. Practitioners used a wide range of criteria to judge their patients' complaints and decide on a course of action. Female practitioners had access to personal and professional experience and used this to develop an understanding of women's complaints. Male practitioners in particular were limited by problems in discussing menstruation in detail. Because of the difficulties in assessing patient history, other non-gynaecological factors such as patient age and consulting behaviour informed practitioners' judgements. CONCLUSION: This study draws attention to practitioners' problems in using current definitions of menstrual disorders. The combination of unhelpful medical definitions, lack of standards of normality and difficulties in discussing menstruation resulted in individual practitioners making judgements in idiosyncratic ways. In the absence of a useful gynaecological model, practitioners develop individual, often subjective and gendered models to use in practice.     

Plötzlicher Brustschmerz und Unterleibsschmerzen

Notfall + Rettungsmedizin - Der plötzliche Brust- und der plötzliche Unterleibsschmerz gehören zu den häufigsten Gründen, die Patienten in die Notaufnahme führen. Das...     

Sex hormone receptor status of the dental pulp and lesions of pulpal origin

OBJECTIVE: The purpose of this study was to determine whether the dental pulp and lesions of pulpal origin (eg, pulp polyps, periapical granulomas, and periapical cysts) exhibit receptors for the sex steroid hormones estrogen, progesterone, and androgen. STUDY DESIGN: Staining for the receptors of the hormones estrogen, progesterone, and androgen was accomplished through use of available immunohistochemical detection techniques. Pulpal tissues were obtained from freshly extracted human third molars; the other tissues were obtained from the Oral and Maxillofacial Pathology Laboratory archives. Ten samples of each tissue were processed and immunostained for these specific receptors. RESULTS: Staining for estrogen and androgen receptors was essentially negative for all cell populations examined. However, positive progesterone receptor staining of varying degrees was noted in 8 of 10 pulpal specimens. Primarily, pulpal fibroblasts and odontoblasts exhibited positive immunoreactivity. CONCLUSIONS: The results of this study suggest that although the dental pulp may be a potential target tissue for progesterone, evidence is lacking with respect to the other sex steroid hormones.     

Low-molecular-weight heparins and heparinoids in acute ischemic stroke : a meta-analysis of randomized controlled trials

BACKGROUND AND PURPOSE: Low-molecular-weight heparins and heparinoids (LMWHs) are superior to unfractionated heparin in the prevention and treatment of venous thromboembolism and acute coronary syndromes. We performed a systematic review of randomized controlled trials (RCTs) to examine the safety and efficacy of LMWH in acute ischemic stroke. METHODS: Randomized, controlled, and nonconfounded trials of LMWH in acute ischemic stroke were identified from the Cochrane Library (version 2, 1999), previous systematic reviews, and a review of publication quality relating to acute stroke trials. The authors each independently extracted data by treatment group and assessed trial quality using Cochrane Collaboration criteria. RESULTS: Eleven completed RCTs involving 3048 patients were identified; data were available from 10 of these. Four trials explicitly excluded patients with presumed cardioembolic stroke. Treatment with LMWH was associated with significant reductions in prospectively identified deep vein thrombosis (OR 0.27, 95% CI 0.08 to 0.96) and symptomatic pulmonary embolism (OR 0.34, 95% CI 0.17 to 0.69) and with increased major extracranial hemorrhage (OR 2.17, 95% 1.10 to 4.28). Nonsignificant increases in end-of-treatment (OR 1.20, 95% CI 0.86 to 1.69) and end-of-trial (OR 1.05, 95% CI 0.83 to 1.32) case fatality and symptomatic intracranial hemorrhage (OR 1.77, 95% CI 0. 95 to 3.31) were observed. End-of-trial death and disability was nonsignificantly reduced (OR 0.87, 95% CI 0.72 to 1.06). CONCLUSIONS: ++LMWHs reduce venous thromboembolic events in patients with acute ischemic stroke and increase the risk of extracranial bleeding. A nonsignificant reduction in combined death and disability and nonsignificant increases in case fatality and symptomatic intracranial hemorrhage were also observed. On the basis of the current evidence, LMWH should not be used in the routine management of patients with ischemic stroke.     

The vestibulo-collic reflex

Until now there has no been no simple, reliable clinical test that assesses the function of the otolith organs. However, recent work has suggested the occurrence of an easily identifiable electromyographic (EMG) waveform in isometrically contracting sternomastoid muscles in response to loud clicks. This is thought to represent an otolith evoked disynaptic reflex. Equipment routinely used for evoked response audiometry (ERA) has been adapted to investigate this response. A short latency (8 ms) positive-negative EMG waveform has been recorded in 31 of 32 normal subjects. The latency of the positive peak (P1) is 11.7 ms ( sd = 0.89), and the negative peak (N1) is 20.5 ms ( sd = 1.89). It is predominantly ipsilateral, although a contralateral response was present in 35.5%. The response has also been recorded in three patients with a severe unilateral sensorineural hearing loss and normal caloric responses, and in a patient undergoing cochlear implantation for profound bilateral sensorineural hearing loss. Further work is required to delineate the value of this technique in investigating vestibular lesions.     

Estimation of markov chain transition probabilities and rates from fully and partially observed data: uncertainty propagation, evidence synthesis, and model calibration.

Markov transition models are frequently used to model disease progression. The authors show how the solution to Kolmogorov's forward equations can be exploited to map between transition rates and probabilities from probability data in multistate models. They provide a uniform, Bayesian treatment of estimation and propagation of uncertainty of transition rates and probabilities when 1) observations are available on all transitions and exact time at risk in each state (fully observed data) and 2) observations are on initial state and final state after a fixed interval of time but not on the sequence of transitions (partially observed data). The authors show how underlying transition rates can be recovered from partially observed data using Markov chain Monte Carlo methods in WinBUGS, and they suggest diagnostics to investigate inconsistencies between evidence from different starting states. An illustrative example for a 3-state model is given, which shows how the methods extend to more complex Markov models using the software WBDiff to compute solutions. Finally, the authors illustrate how to statistically combine data from multiple sources, including partially observed data at several follow-up times and also how to calibrate a Markov model to be consistent with data from one specific study.