Impact of hemodialysis on P-wave amplitude, duration, and dispersion

Atrial fibrillation (AF) is a frequent arrhythmia in patients undergoing hemodialysis (HD). P wave duration (PWdu) and P wave dispersion (PWdi) have been shown to be predictors of emerging AF in different clinical conditions. We sought to study the impact of HD on PWdu, PWdi, and P wave amplitude in a cohort of patients undergoing HD. Seventeen patients (8 men, 31+/-10 years) were studied. Echocardiography parameters, the sum of the amplitude of P waves in all 12 ECG leads (SP), mean PWdu, and PWdi, along with a host of other parameters (body weight, heart rate, electrolytes and hemoglobin/hematochrit) were measured 1/2h, before and after, HD. SP increased (11.8+/-3.9 vs 15.3+/-4.0 mm, p = 0.004), mean PWdu remained stable (82.7+/-11.1 vs 81.6+/-10.5 ms, p = 0.606), PWdi decreased (51.7+/-19.1 vs 41.7+/-19.1 ms, p = 0.03), and left atrial dimension decreased (37.96+/-3.90 vs 30.62+/-3.38 mm, p = 0.0001), after HD. The change in PWdi correlated with fluid removed by HD (r = -0.55, p = 0.022). Re-measurements of P-wave parameters in a random group of 11 of the 17 patients revealed augmented SP (p = 0.01), and stable mean PWdu (p = 0.36), and PWdi (p = 0.31), after HD. Fluid removed by HD leads to an increase in SP, a stable mean PWdu, and decrease (or stability on re-measurement in a subgroup of patients) in PWdi. Stability of PWdu may be due to the effects of augmentation of the P-wave amplitude and the reduction of the left atrial volume, cancelling each other. Variability of PWdi may stem from the occasional impossibility to measure PWdu (or measure it correctly) in minute P-waves in certain ECG leads, which in turn profoundly affects the PWdi.     

Insight into the mechanism of lipids binding and uptake by CD36 receptor

The membrane protein CD36 is a member of the class B scavenger receptor family. It plays a crucial role in some cardiovascular pathologies and metabolic diseases. Studying the mechanism of action of CD36 receptor is limited due to the absence of its tridimensional crystallized structure. The molecular docking method has allowed us to perform various simulation of the CD36 receptor interaction with their ligands involved in the development of some diseases. In this work, we predicted a tridimensional structure model of CD36 extracellular domain. In addition, we have achieved several tests of rigid and flexible docking by acting on residues proposed in previous experimental researches as essential in fixing of LFCAs. Furthermore, we have acted on regions that appear a key binding site of LFCAs. The physicoc hemical evaluation indicated the reliability of the proposed CD36 structure used for different molecular docking tests. Based on the docking outcome, we were able to propose the different steps of the mechanism allowing the interaction of fatty acids on CD36 receptor and their penetration into the cell cytoplasm. The obtained results and taking in consideration CD36 receptor as a therapeutic target will help us to suggest the mechanism by which an antagonist may inhibit this receptor by acting on its extracellular domain.     

Biomedical engineering continues to make the future

Biomedical engineering (BME) continues to make the future, not just respond to the present, by anticipating the needs of interface engineering and clinical medicine. In many respects, BME is the educational mode of the future, fostering collaboration among disciplines at its core by building on basic concepts in engineering and biology. We strive to educate where the needs, opportunities, and jobs are and will be in the future. The bridge between engineering, biology, and medicine is a growing link, and there is no sign that this interface will slow. With an aging population, dynamic changes in health care, as well as global economies and related themes upon us, we are only at the very beginning of the impact that BME will have on medicine and the quality of life. Those of us in BME are excited to be setting this agenda and welcome your participation. In part, this is why we have designed our BME major to cover both the depth and breadth, always a challenge, but one that we are committed to. The depth of the design projects, research experience, coursework, study abroad options, and internships all convenes to establish a solid foundation for our students as they embark on their career paths.     

Impuissance et examens complémentaires

Impotence is a symptom whose origin is most often multifactorial. Erection is a complex musculo-vascular phenomenon under peripheral nervous control regulated by the central nervous system and under hormonal control. Failure of erection may be due to a perturbation at any of these levels of control. Numerous complementary investigations are available to therapists: endocrine profiles, intracavernosal injection of vaso-active compounds, penile doppler ultrasonography, plethysmography; and visual stimulation tests.     

Haloperidol treatment at pre-exposure phase reduces the disturbance of latent inhibition in rats with neonatal ventral hippocampus lesions

Animals with neonatal ventral hippocampal lesions develop during or after adolescence abnormal behaviors related to schizophrenia such as anxiety and latent inhibition disruption. The aim of this study was to test whether haloperidol injection prior to pre-exposure session in the latent inhibition test would facilitate latent inhibition.     

Clock Genes and Behavioral Responses to Light Are Altered in a Mouse Model of Diabetic Retinopathy

There is increasing evidence that melanopsin-expressing ganglion cells (ipRGCs) are altered in retinal pathologies. Using a streptozotocin-induced (STZ) model of diabetes, we investigated the impact of diabetic retinopathy on non-visual functions by analyzing ipRGCs morphology and light-induced c-Fos and Period 1–2 clock genes in the central clock (SCN). The ability of STZ-diabetic mice to entrain to light was challenged by exposure animals to 1) successive light/dark (LD) cycle of decreasing or increasing light intensities during the light phase and 2) 6-h advance of the LD cycle. Our results show that diabetes induces morphological changes of ipRGCs, including soma swelling and dendritic varicosities, with no reduction in their total number, associated with decreased c-Fos and clock genes induction by light in the SCN at 12 weeks post-onset of diabetes. In addition, STZ-diabetic mice exhibited a reduction of overall locomotor activity, a decrease of circadian sensitivity to light at low intensities, and a delay in the time to re-entrain after a phase advance of the LD cycle. These novel findings demonstrate that diabetes alters clock genes and behavioral responses of the circadian timing system to light and suggest that diabetic patients may show an increased propensity for circadian disturbances, in particular when they are exposed to chronobiological challenges.     

Potassium monopersulfate and a water-soluble manganese porphyrin complex, [Mn(TMPyP)](OAc)5, as an efficient reagent for the oxidative cleavage of DNA

Reported studies indicate that the association of potassium monopersulfate with [Mn(TMPyP)](OAc)5, a water-soluble manganese porphyrin complex, leads to an efficient reagent for the oxidative cleavage of DNA. Single-strand breaks (SSBs) are observed on double-stranded DNA at manganese porphyrin concentrations as low as 0.5 nM with a short incubation time of 1 min. The number of SSBs linearly varies with the concentration of the manganese complex, and potassium monopersulfate is at least 3 orders of magnitude more efficient as oxygen source than hydrogen peroxide. Cleavage efficiency is optimal in the pH range 7.5-9.0 for a NaCl concentration between 80 and 150 mM or for a MgCl2 concentration of 10 mM. At very low manganese porphyrin concentration and by increasing the incubation time a catalytic cleavage activity of the complex is evidenced: up to 5 SSBs per manganese porphyrin are observed. The high cleavage activity of the monopersulfate-manganese porphyrin system makes it a good candidate for DNA-footprinting experiments.     

Stabilization of the gaze in chameleons: visual and vestibular reflexes

Some visual, vestibular and proprioceptive reflexes which contribute to gaze (head + eye) stabilization were quantified in the chameleon. All the reflexes were analysed in the horizontal plane, and the visual reflexes were also studied in the vertical plane. In restrained-head animals, both the optokinetic nystagmus (OKN) and the vestibulo-ocular reflex (VOR) had low gains. In free-head animals, the head (opto-collic or vestibulo-collic reflex) and eye (OKN or VOR) responses added their effects, thus improving gaze stabilization, especially during vestibular stimulation. Cervical stimulation provoked both a cervico-ocular reflex (COR) in the compensatory direction and a large number of saccades. The saccadic response was especially marked in the presence of patterned visual surroundings.