109 resultados para medical optics and biotechnology
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This nested case-control analysis of a Swiss ambulatory cohort of elderly women assessed the discriminatory power of urinary markers of bone resorption and heel quantitative ultrasound for non-vertebral fractures. The tests all discriminated between cases and controls, but combining the two strategies yielded no additional relevant information. INTRODUCTION: Data are limited regarding the combination of bone resorption markers and heel quantitative bone ultrasound (QUS) in the detection of women at risk for fracture. METHODS: In a nested case-control analysis, we studied 368 women (mean age 76.2 +/- 3.2 years), 195 with low-trauma non-vertebral fractures and 173 without, matched for age, BMI, medical center, and follow-up duration, from a prospective study designed to predict fractures. Urinary total pyridinolines (PYD) and deoxypyridinolines (DPD) were measured by high performance liquid chromatography. All women underwent bone evaluations using Achilles+ and Sahara heel QUS. RESULTS: Areas under the receiver operating-characteristic curve (AUC) for discriminative models of the fracture group, with 95% confidence intervals, were 0.62 (0.56-0.68) and 0.59 (0.53-0.65) for PYD and DPD, and 0.64 (0.58-0.69) and 0.65 (0.59-0.71) for Achilles+ and Sahara QUS, respectively. The combination of resorption markers and QUS added no significant discriminatory information to either measurement alone with an AUC of 0.66 (0.60-0.71) for Achilles+ with PYD and 0.68 (0.62-0.73) for Sahara with PYD. CONCLUSIONS: Urinary bone resorption markers and QUS are equally discriminatory between non-vertebral fracture patients and controls. However, the combination of bone resorption markers and QUS is not better than either test used alone.
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Ligament balance is an important and subjective task performed during total knee arthroplasty (TKA) procedure. For this reason, it is desirable to develop instruments to quantitatively assess the soft-tissue balance since excessive imbalance can accelerate prosthesis wear and lead to early surgical revision. The instrumented distractor proposed in this study can assist surgeons on performing ligament balance by measuring the distraction gap and applied load. Also the device allows the determination of the ligament stiffness which can contribute a better understanding of the intrinsic mechanical behavior of the knee joint. Instrumentation of the device involved the use of hall-sensors for measuring the distractor displacement and strain gauges to transduce the force. The sensors were calibrated and tested to demonstrate their suitability for surgical use. Results show the distraction gap can be measured reliably with 0.1mm accuracy and the distractive loads could be assessed with an accuracy in the range of 4N. These characteristics are consistent with those have been proposed, in this work, for a device that could assist on performing ligament balance while permitting surgeons evaluation based on his experience. Preliminary results from in vitro tests were in accordance with expected stiffness values for medial collateral ligament (MCL) and lateral collateral ligament (LCL).
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ABSTRACT: BACKGROUND: Decision curve analysis has been introduced as a method to evaluate prediction models in terms of their clinical consequences if used for a binary classification of subjects into a group who should and into a group who should not be treated. The key concept for this type of evaluation is the "net benefit", a concept borrowed from utility theory. METHODS: We recall the foundations of decision curve analysis and discuss some new aspects. First, we stress the formal distinction between the net benefit for the treated and for the untreated and define the concept of the "overall net benefit". Next, we revisit the important distinction between the concept of accuracy, as typically assessed using the Youden index and a receiver operating characteristic (ROC) analysis, and the concept of utility of a prediction model, as assessed using decision curve analysis. Finally, we provide an explicit implementation of decision curve analysis to be applied in the context of case-control studies. RESULTS: We show that the overall net benefit, which combines the net benefit for the treated and the untreated, is a natural alternative to the benefit achieved by a model, being invariant with respect to the coding of the outcome, and conveying a more comprehensive picture of the situation. Further, within the framework of decision curve analysis, we illustrate the important difference between the accuracy and the utility of a model, demonstrating how poor an accurate model may be in terms of its net benefit. Eventually, we expose that the application of decision curve analysis to case-control studies, where an accurate estimate of the true prevalence of a disease cannot be obtained from the data, is achieved with a few modifications to the original calculation procedure. CONCLUSIONS: We present several interrelated extensions to decision curve analysis that will both facilitate its interpretation and broaden its potential area of application.
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The Cognitive Performance Scale (CPS) was initially designed to assess cognition in long term care residents. Subsequently, the CPS has also been used among in-home, post-acute, and acute care populations even though CPS' clinimetric performance has not been studied in these settings. This study aimed to determine CPS agreement with the Mini Mental Status Exam (MMSE) and its predictive validity for institutionalization and death in a cohort (N=401) of elderly medical inpatients aged 75 years and over. Medical, physical and mental status were assessed upon admission. The same day, the patient's nurse completed the CPS by interview. Follow-up data were gathered from the central billing system (nursing home stay) and proxies (death). Cognitive impairment was present in 92 (23%) patients according to CPS (score >or= 2). Agreement with MMSE was moderate (kappa 0.52, P<.001). Analysis of discordant results suggested that cognitive impairment was overestimated by the CPS in dependent patients with comorbidities and depressive symptoms, and underestimated in older ones. During follow-up, subjects with abnormal CPS had increased risks of death (adjusted hazard ratio (adjHR) 1.7, 95% CI 1.0-2.8, P=.035) and institutionalization (adjHR 2.7, 95% CI 1.3-5.3, P=.006), independent of demographic, health and functional status. Interestingly, subjects with abnormal CPS were at increased risk of death only if they also had abnormal MMSE. The CPS predicted death and institutionalization during follow-up, but correlated moderately well with the MMSE. Combining CPS and MMSE provided additional predictive information, suggesting that domains other than cognition are assessed by professionals when using the CPS in elderly medical inpatients.
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Dermatologic surgery has evolved enormously within the past few years especially for the treatment of varicose veins and telangiectasias. New minimally-invasive techniques have been developed: lasers, echo-sclerosis, surgery with tumescent anesthesia and endovascular treatment of saphenous veins. Most interventions can be performed with local anesthesia in the office setting. These new treatments are intended to decrease the risks of surgery, reduce medical costs and the necessity for hospitalization, and improve functional and esthetic results.
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To determine incidence and type of major cardiac adverse events in patients with mutated desmin (DES) gene, we retrospectively reviewed baseline medical information, and examined the long-term outcomes of 28 DES patients (17 men, baseline mean age=37.7±14.4 years [min=9, max=71]) from 19 families. Baseline studies revealed skeletal muscle involvement in 21 patients and cardiac abnormalities in all but one patient. Over a mean follow-up of 10.4±9.4 years [min=1, max=35], cardiac death occurred in three patients, death due to cardiac comorbidities in two, one or more major cardiac adverse events in 13 patients. Among the 19 patients with mild conduction defects at baseline, eight developed high-degree conduction blocks requiring permanent pacing. Cardiac involvement was neither correlated with the type of DES mutation nor with the severity of skeletal muscle involvement. Our study underscores that in DES patients in-depth cardiac investigations are needed to prevent cardiac conduction system disease.
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BACKGROUND: Home hospital is advocated in many western countries in spite of limited evidence of its economic advantage over usual hospital care. Heart failure and community-acquired pneumonia are two medical conditions which are frequently targeted by home hospital programs. While recent trials were devoted to comparisons of safety and costs, the acceptance of home hospital for patients with these conditions remains poorly described. OBJECTIVE: To document the medical eligibility and final transfer decision to home hospital for patients hospitalized with a primary diagnosis of heart failure or community-acquired pneumonia. DESIGN: Longitudinal study of patients admitted to the medical ward of acute care hospitals, up to the final decision concerning their transfer. SETTING: Medical departments of one university hospital and two regional teaching Swiss hospitals. PATIENTS: All patients admitted over a 9 month period to the three settings with a primary diagnosis of heart failure (n= 301) or pneumonia (n=441). MEASUREMENTS: Presence of permanent exclusion criteria on admission; final decision of (in)eligibility based on medical criteria; final decision regarding the transfer, taking into account the opinions of the family physician, the patient and informal caregivers. RESULTS: While 27.9% of heart failure and 37.6% of pneumonia patients were considered to be eligible from a medical point of view, the program acceptance by family physicians, patients and informal caregivers was low and a transfer to home hospital was ultimately chosen for just 3.8% of heart failure and 9.6% of pneumonia patients. There were no major differences between the three settings. CONCLUSIONS: In the case of these two conditions, the potential economic advantage of home hospital over usual inpatient care is compromised by the low proportion of patients ultimately transferred.
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Smoking is not only the most important source of avoidable disability and death, but a risk factor for TB infection, disease and death. Even passive smoking exposure may increase the risk of infection and disease in adults and children exposed to TB. Considering the increase in tobacco consumption in developing countries, where the prevalence of TB is the highest, smoking may be responsible for a large part of the burden of disease. Therefore, medical advice and counselling in smoking cessation is an important activity for all care providers engaged in management of TB
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The interest in sexuality of adolescents in medical practice is often mainly focussed on the onset of sexual intercourse and on the emergence of contraceptive needs, though the beginning of adolescence takes place much earlier with the first signs of puberty followed by the menarche. At the issue of this profound metamorphosis the adolescent needs to adapt herself to a modified, sexual body. Adolescence is also a time of identity development and of changes in relationships, which are influenced by gender role in family and perception related to gender during childhood. This article shows epidemiological data to consider and the main issues of gynaecologic consultation with the adolescent. The different stages of development depend on biological and environmental factors which either favour resilience or weaken the individual due to a lack of affection or to abusive relationships. Medical consultation for a gynaecological problem, questions on puberty and development or on contraception give medical professionals and especially gynaecologists a chance to address sexual issues naturally, to anticipate questions as well as contraceptive needs. The consultation with the adolescent includes also the screening for behaviour related to a lack of information or a personal or relational difficulty.
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The demonstration of beneficial effects of cell therapy despite the persistence of only few transplanted cells in vivo suggests secreted factors may be the active component of this treatment. This so-called paracrine hypothesis is supported by observations that culture media conditioned by progenitor cells contain growth factors that mediate proangiogenic and cytoprotective effects. Cardiac progenitor cells in semi-suspension culture form spherical clusters (cardiospheres) that deliver paracrine signals to neighboring cells. A key component of paracrine secretion is exosomes, membrane vesicles that are stored intracellularly in endosomal compartments and are secreted when these structures fuse with the cell plasma membrane. Exosomes have been identified as the active component of proangiogenic effects of bone marrow CD34(+) stem cells in mice and the regenerative effects of embryonic mesenchymal stem cells in infarcted hearts in pigs and mice. Here, we provide electron microscopic evidence of exosome secretion by progenitor cells in mouse myocardium and human cardiospheres. Exosomes are emerging as an attractive vector of paracrine signals delivered by progenitor cells. They can be stored as an "off-the-shelf" product. As such, exosomes have the potential for circumventing many of the limitations of viable cells for therapeutic applications in regenerative medicine.
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Background: Visual analog scales (VAS) are used to assess readiness to changeconstructs, which are often considered critical for change.Objective: We studied whether 3 constructs -readiness to change, importance of changing and confidence inability to change- predict risk status 6 months later in 20 year-old men with either orboth of two behaviors: risky drinking and smoking. Methods: 577 participants in abrief intervention randomized trial were assessed at baseline and 6 months later onalcohol and tobacco consumption and with three 1-10 VAS (readiness, importance,confidence) for each behavior. For each behavior, we used one regression model foreach constructs. Models controlled for receipt of a brief intervention and used thelowest level (1-4) in each construct as the reference group (vs medium (5-7) and high(8-10) levels).Results: Among the 475 risky drinkers, mean (SD) readiness, importance and confidence to change drinking were 4.0 (3.1), 2.8 (2.2) and 7.2 (3.0).Readiness was not associated with being alcohol-risk free 6 months later (OR 1.3[0.7; 2.2] and 1.4 [0.8; 2.6] for medium and high readiness). High importance andhigh confidence were associated with being risk free (OR 0.9 [0.5; 1.8] and 2.9 [1.2;7.5] for medium and high importance; 2.1 [1.0;4.8] and 2.8 [1.5;5.6] for medium andhigh confidence). Among the 320 smokers, mean readiness, importance andconfidence to change smoking were 4.6 (2.6), 5.3 (2.6) and 5.9 (2.6). Neitherreadiness nor importance were associated with being smoking free (OR 2.1 [0.9; 4.7]and 2.1 [0.8; 5.8] for medium and high readiness; 1.4 [0.6; 3.4] and 2.1 [0.8; 5.4] formedium and high importance). High confidence was associated with being smokingfree (OR 2.2 [0.8;6.6] and 3.4 [1.2;9.8] for medium and high confidence).Conclusions: For drinking and smoking, high confidence in ability to change wasassociated -with similar magnitude- with a favorable outcome. This points to thevalue of confidence as an important predictor of successful change.
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Renal and testicular cancers account for 4% and 1% of all malignancies, respectively. Their prevalence has increased over the past years and is related to the widespread use of medical imaging and the incidental findings of small asymptomatic tumors on computed tomography scanners and ultrasounds examinations. The urologist faces the dilemma of overtreating benign asymptomatic lesions with radical surgery. Therefore, organ-sparing surgery was developed. Recent studies have shown that recurrence rates are often similar between organ-sparing and radical surgery for small kidney or testicular tumors. However, the risk of positive surgical margins consecutive to organ-sparing surgery remains a matter of debate. This article discusses the role of ex-vivo peroperative ultrasonography in predicting negative surgical margins during kidney- and testicular-sparing surgery.
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The kinetics of binding of a glycolipid-anchored protein (the promastigote surface protease, PSP) to planar lecithin bilayers is studied by an integrated optics technique, in which the bilayer membrane is supported on an optical wave guide and the phase velocities of guided light modes in the wave guide are measured. From these velocities, the optical parameters of the membrane and PSP layers deposited on the waveguide are determined, yielding in particular the mass of PSP bound to the membrane, which is followed in real time. From a comparison of the binding rates of PSP and PSP from which the lipid moiety has been removed, it is shown that the lipid moiety plays a key role in anchoring the protein to the membrane. Specific and nonspecific binding of antibodies to membrane-anchored PSP is also investigated. As little as a fifth of a monolayer of PSP is sufficient to suppress the appreciable nonspecific binding of antibodies to the membrane.