Prevalence and risk factors of silent brain infarcts in patients with AF detected by 3T-MRI

Journal of Neurology - Silent brain infarcts (SBI), a finding on neuroimaging, are associated with higher risk of future stroke. Atrial Fibrillation (AF) has been previously identified as a cause...     

Effect of different doses of iron supplementation during pregnancy on maternal and infant health

Currently, there is no consensus regarding the optimum iron supplementation during pregnancy. The aim of this study is to evaluate the effect of different iron supplementation doses (including no supplementation) during pregnancy on the iron status of the mother and on the health of the neonate. A longitudinal study was conducted involving 358 pregnant women and their newborns. Mothers were classified as non-supplemented, low iron supplemented (<60 mg/day), moderate iron supplemented (between 60 and 100 mg/day) or high iron supplemented (>100 mg/day). General clinical and obstetric histories, haemoglobin (Hb), serum ferritin (SF) and transferrin saturation were evaluated in the first, second, third trimesters, and at partum. SF and Hb decreased less sharply in the iron-supplemented groups compared to the non-supplemented group. The higher the doses of iron supplementation, the lower the percentages of iron depletion at partum (p?<?0.001), iron deficiency anaemia (p?<?0.001) and preterm deliveries (p?=?0.009) as well as a higher birth weight of the newborn. However, the group with high supplementation had a greater percentage (27.6 %) of women at risk of haemoconcentration at partum. Our Mediterranean women began gestation with iron stores close to deficit (SF, 28.1 μg/L; 95 % CI 27.9–28.4). With these iron stores, supplementation with iron at daily doses of between 60 and 100 mg appears to be the most beneficial for the health of mother and child. These findings need to be confirmed in further randomised clinical trials.     

Chronic hyperammonemia alters the circadian rhythms of corticosteroid hormone levels and of motor activity in rats

Patients with liver cirrhosis may present hepatic encephalopathy with a wide range of neurological disturbances and alterations in sleep quality and in the sleep‐wake circadian rhythm. Hyperammonemia is a main contributor to the neurological alterations in hepatic encephalopathy. We have assessed, in an animal model of chronic hyperammonemia without liver failure, the effects of hyperammonemia per se on the circadian rhythms of motor activity, temperature, and plasma levels of adrenal corticosteroid hormones. Chronic hyperammonemia alters the circadian rhythms of locomotor activity and of cortisol and corticosterone levels in blood. Different types of motor activity are affected differentially. Hyperammonemia significantly alters the rhythm of spontaneous ambulatory activity, reducing strongly ambulatory counts and slightly average velocity during the night (the active phase) but not during the day, resulting in altered circadian rhythms. In contrast, hyperammonemia did not affect wheel running at all, indicating that it affects spontaneous but not voluntary activity. Vertical activity was affected only very slightly, indicating that hyperammonemia does not induce anxiety. Hyperammonemia abolished completely the circadian rhythm of corticosteroid hormones in plasma, completely eliminating the peaks of cortisol and corticosterone present in control rats at the start of the dark period. The data reported show that chronic hyperammonemia, similar to that present in patients with liver cirrhosis, alters the circadian rhythms of corticosteroid hormones and of motor activity. This suggests that hyperammonemia would be a relevant contributor to the alterations in corticosteroid hormones and in circadian rhythms in patients with liver cirrhosis. © 2009 Wiley‐Liss, Inc.     

Efficient purification of the biosurfactant viscosin from Pseudomonas libanensis strain M9-3 and its physicochemical and biological properties

Viscosin (1), an effective surface-active cyclic lipopeptide, was efficiently recovered from Pseudomonas libanensis M9-3 with a simple purification protocol. A major pigment also obtained during this process was identified as phenazine-1-carboxylic acid. The critical micelle concentration (cmc) of viscosin was determined to be 54 mg L (-1), and the minimum surface tension between air and water at the cmc was 28 mN m (-1). Viscosin forms stable emulsions even at low concentrations (7.5 mg L (-1)), and the conditional stability constant for a cadmium-viscosin complex was determined to be 5.87. The physicochemical properties measured for viscosin are similar to other well-studied biosurfactants such as rhamnolipid and surfactin. Viscosin inhibited migration of the metastatic prostate cancer cell line, PC-3M, without visible toxicity. These properties suggest the potential of viscosin in environmental and biomedical applications.     

The regenerative potential of fibroblasts in a new diabetes‐induced delayed humanised wound healing model

Cutaneous diabetic wounds greatly affect the quality of life of patients, causing a substantial economic impact on the healthcare system. The limited clinical success of conventional treatments is mainly attributed to the lack of knowledge of the pathogenic mechanisms related to chronic ulceration. Therefore, management of diabetic ulcers remains a challenging clinical issue. Within this context, reliable animal models that recapitulate situations of impaired wound healing have become essential. In this study, we established a new in vivo humanised model of delayed wound healing in a diabetic context that reproduces the main features of the human disease. Diabetes was induced by multiple low doses of streptozotocin in bioengineered human‐skin‐engrafted immunodeficient mice. The significant delay in wound closure exhibited in diabetic wounds was mainly attributed to alterations in the granulation tissue formation and resolution, involving defects in wound bed maturation, vascularisation, inflammatory response and collagen deposition. In the new model, a cell‐based wound therapy consisting of the application of plasma‐derived fibrin dermal scaffolds containing fibroblasts consistently improved the healing response by triggering granulation tissue maturation and further providing a suitable matrix for migrating keratinocytes during wound re‐epithelialisation. The present preclinical wound healing model was able to shed light on the biological processes responsible for the improvement achieved, and these findings can be extended for designing new therapeutic approaches with clinical relevance.     

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.