Plasma rico en plaquetas: ¿un nuevo tratamiento para el reumatólogo?

Platelet Rich Plasma (PRP) is a novel therapeutic tool that has revolutionized the world of sports medicine and trauma due to therapeutic success shown in the media. Subject to ongoing debate, the PRP is outlined along a spectrum of musculoskeletal therapies with many qualities that make it ideal for use in the rheumatology: effectiveness, safety, easy handling and low cost. Is PRP a product of marketing? Or, conversely, is an interesting tool to consider in the armamentarium of the rheumatologist. In the following review we will analyze in detail its principles, preparation, and management regimes. We will reflect on potential adverse effects and, finally, there will be a critical analysis of the scientific evidence that supports its potential use in the rheumatology clinic.     

Circadian Variation in Circulating Platelet Aggregates

The mitochondrial F₁F_o adenosine triphosphate (ATP) synthase is one of the most thoroughly studied enzyme complexes known. Yet, a number of new observations suggesting that the enzyme is also located on the cell surface necessitate further investigation. While the mitochondrial synthase utilizes the proton gradient generated by oxidative phosphorylation to power ATP synthesis, the cell surface synthase has instead been implicated in numerous activities, including the mediation of intracellular pH, cellular response to antiangiogenic agents, and cholesterol homeostasis. Intriguingly, a common thread uniting these various models of cell surface ATP synthase functions is the apparently caveolar distribution of the enzyme. Recent studies concerning the cell surface ATP synthase manifest applications in the regulation of serum cholesterol levels, cellular proliferation and antitumor strategies. This review addresses the expression, interactions, functions, and consequences of inhibition of cell surface ATP synthase, an enzyme now displaying a shift in paradigm, as well as of location.     

Nutrient and Fiber Intake and Risk of Renal Cell Carcinoma

This study examines the association between nutrient and fiber intake and the risk of renal cell carcinoma (RCC). Between 1994 and 1997 in 8 Canadian provinces, mailed questionnaires were completed by 1,138 incident, histologically confirmed cases of RCC and 5,039 population controls. Measurement included information on socioeconomic status, lifestyle habits, and diet. A 69-item food frequency questionnaire provided data on eating habits 2 yr before data collection. Odds ratios (ORs) and 95% confidence intervals were derived through unconditional logistic regression. Intakes of total fat, saturated fat, monounsaturated fat, trans-fat, and cholesterol were associated with the risk of RCC; the ORs for the highest vs. the lowest quartile were 1.67, 1.53 and 1.46, 1.31, and 1.48, respectively. The positive association was apparently stronger in women, overweight or obese, and never smokers. Sucrose was related to the risk of RCC. High fiber intake was inversely associated with RCC risk. No association was found with intake of total protein and polyunsaturated fat, n-3 and n-6 polyunsaturated fatty acids, and total carbohydrates. The results were consistent across strata of sex, tobacco, and BMI. The findings suggest that a diet low in fats and cholesterol and rich in fiber could favorably affect the risk of RCC.     

Translating the oxidative stress hypothesis into the clinic: NOX versus NOS

Cardiovascular diseases remain the leading cause of death in industrialised nations. Since the pathomechanisms of most cardiovascular diseases are not understood, the majority of therapeutic approaches are symptom-orientated. Knowing the molecular mechanism of disease would enable more targeted therapies. One postulated underlying mechanism of cardiovascular diseases is oxidative stress, i.e. the increased occurrence of reactive oxygen species such as superoxide. Oxidative stress leads to a dysfunction of vascular endothelium-dependent protective mechanisms. There is growing evidence that this scenario also involves impaired nitric oxide (NO)-cyclic GMP signalling. Out of a number of enzyme families that can produce reactive oxygen species, NADPH oxidases stand out, as they are the only enzymes whose sole purpose is to produce reactive oxygen species. This review focuses on the clinically validated targets of oxidative stress, NO synthase (NOS) and the NO receptor, soluble guanylate cyclase as well as the source of ROS, e.g. NADPH oxidases. We place recent knowledge in the function and regulation of these enzyme families into clinical perspective. For a comprehensive overview of the biology and pharmacology of oxidative stress and possible other sources and targets, we refer to other literature overviews.     

Continuing Medical Education Program in Echocardiography

Article Title: Left Ventricular Torsion Parameters are Affected by Acute Changes in Load (Echocardiography 2010;27:406)     

Multiscale Time Irreversibility of Heartbeat at Rest and During Aerobic Exercise

The multiscale time irreversibility (MTI) involves the lack of consistency in the properties of a time series if one reverses the reading direction along the time. To analyze the RR time series at rest and during aerobic exercise through the MTI, both in healthy people and cardiac patients. The heartbeat signal was recorded beat to beat for 15 min at rest and 15 min while pedalling on a static bicycle in 10 healthy and active men (age 26.5 ± 3.3 years; height 179.3 ± 6.6 cm; weight 80.4 ± 11.8 kg) and 10 cardiac patients (age 61.1 ± 4.7 years, height 165.3 ± 5.3 cm; weight 86.9 ± 11.1 kg). The MTI was calculated through the asymmetry index (AI), defined as the sum of the values of asymmetry obtained for each scale from 1 to 10. The AI decreases significantly in healthy subjects from 0.51 ± 0.28 at rest to 0.28 ± 0.24 during exercise (P = 0.01) but not in cardiac patients (?0.2204 ± 0.5097 at rest and 0.0848 ± 0.1200 during exercise; P = 0.07). MTI distinguish adequately the four experimental situations because it can be considered as an index of the internal property of the signal in contrast to linear methods which are highly sensitive to external influences over the heart rhythm, particularly sympathetic and parasympathetic stimuli.