Longitudinal analysis of echocardiographic and cardiac biomarker variables in dogs with atrial fibrillation: The optimal rate control in dogs with atrial fibrillation II study.

BACKGROUND: Rate control (RC; meanHRHolter ≤ 125 bpm) increases survival in dogs with atrial fibrillation (AF). The mechanisms remain unclear. HYPOTHESIS/OBJECTIVES: Investigate echocardiographic and biomarker differences between RC and non-RC (NRC) dogs. Determine if changes post-anti-arrhythmic drugs (AAD) predict successful RC in subsequent Holter monitoring. Evaluate if early vs late RC affects survival. ANIMALS: Fifty-two dogs with AF. METHODS: Holter-derived mean heart rate, echocardiographic and biomarker variables from dogs receiving AAD were analyzed prospectively at each re-evaluation and grouped into RC or NRC. The primary endpoint was successful RC. Between group comparisons of absolute values, magnitude of change from admission to re-evaluations and end of study were performed using Mann-Whitney tests or unpaired t-tests. Logistic regression explored variables associated with inability to achieve RC at subsequent visits. Kaplan-Meier survival analysis was used to compare survival time of early vs late RC. RESULTS: At visit 2, 11/52 dogs were RC; at visit 3, 14/52 were RC; and at visit 4, 4/52 were RC. At the end of study, 25/52 remained NRC. At visit 2, both groups had increased cardiac dimensions, but NRC dogs had larger dimensions; biomarkers did not differ. At the end of study, RC showed decreased cardiac dimensions and end-terminal pro-brain natriuretic peptide (NT-proBNP) compared with NRC. No variables were useful at predicting RC success in subsequent visits. Survival analysis found no differences between early vs late RC. CONCLUSIONS AND CLINICAL IMPORTANCE: The RC dogs had decreased cardiac dimensions and NT-proBNP, suggesting HR-mediated reverse-remodeling might benefit survival, even with delayed RC achievement. Pursuit of RC is crucial despite initial failures.

Multisystemic RFC1-Related Disorder: Expanding the Phenotype Beyond Cerebellar Ataxia, Neuropathy, and Vestibular Areflexia Syndrome.

Background and Objectives: The RFC1 spectrum has become considerably expanded as multisystemic features beyond the triad of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) have started to be unveiled, although many still require clinical replication. Here, we aimed to clinically characterize a cohort of RFC1-positive patients by addressing both classic and multisystemic features. In a second part of this study, we prospectively assessed small nerve fibers (SNF) and autonomic function in a subset of these RFC1-related patients. Methods: We retrospectively enrolled 67 RFC1-positive patients from multiple neurologic centers in Portugal. All patients underwent full neurologic and vestibular evaluation, as well as neuroimaging and neurophysiologic studies. For SNF and autonomic testing (n = 15), we performed skin biopsies, quantitative sensory testing, sudoscan, sympathetic skin response, heart rate deep breathing, and tilt test. Results: Multisystemic features beyond CANVAS were present in 82% of the patients, mainly chronic cough (66%) and dysautonomia (43%). Other features included motor neuron (MN) affection and motor neuropathy (18%), hyperkinetic movement disorders (16%), sleep apnea (6%), REM and non-REM sleep disorders (5%), and cranial neuropathy (5%). Ten patients reported an inverse association between cough and ataxia severity. A very severe epidermal denervation was found in skin biopsies of all patients. Autonomic dysfunction comprised cardiovascular (67%), cardiovagal (54%), and/or sudomotor (50%) systems. Discussion: The presence of MN involvement, motor neuropathy, small fiber neuropathy, or extrapyramidal signs should not preclude RFC1 testing in cases of sensory neuronopathy. Indeed, the RFC1 spectrum can overlap not only with multiple system atrophy but also with hereditary motor and sensory neuropathy, hereditary sensory and autonomic neuropathy, and feeding dystonia phenotypes. Some clinical-paraclinical dissociations can pose diagnostic challenges, namely large and small fiber neuropathy and sudomotor dysfunction which are usually subclinical.

Optimal rate control in dogs with atrial fibrillation-ORCA study-Multicenter prospective observational study: Prognostic impact and predictors of rate control.

BACKGROUND: The optimal heart rate (HR) in dogs with atrial fibrillation (AF) is unknown. Impact of HR on survival needs elucidation. HYPOTHESIS/OBJECTIVES: Dogs with a 24 hours Holter-derived meanHR ≤125 beats per minute (bpm; rate controlled) survive longer than dogs with higher meanHR. We further aimed to determine which variables predict ability to achieving rate control. ANIMALS: Sixty dogs with AF. METHODS: Holter-derived meanHR, clinical, echocardiographic, and biomarker variables were analyzed prospectively. Survival was recorded from time of rate control, with all-cause mortality as primary endpoint. Cox proportional hazards analysis identified variables independently associated with survival; Kaplan-Meier survival analysis estimated the median survival time of dogs with meanHR ≤125 bpm vs >125 bpm. Logistic regression explored baseline variables associated with inability to achieve rate control. RESULTS: Structural heart disease was present in 56/60 dogs, 50/60 had congestive heart failure, and 45/60 died. Median time to all-cause death was 160 days (range, 88-303 days), dogs with meanHR >125 bpm (n = 27) lived 33 days (95% confidence interval [CI], 15-141 days), dogs with meanHR ≤125 bpm (n = 33) lived 608 days (95% CI, 155-880 days; P < .0001). Congenital heart disease and N-terminal pro-B-type natriuretic peptide were independently associated with higher risk of death (P < .01 and <.0001, respectively) whereas meanHR ≤125 bpm decreased the risk of death (P < .001). Increased left atrial size, increased C-reactive protein concentration and lower blood pressure at admission were associated with failure to achieve rate control. CONCLUSIONS AND CLINICAL IMPORTANCE: Rate control affects survival; an optimal target meanHR <125 bpm should be sought in dogs with AF. Baseline patient variables can help predict if rate control is achievable.

Individual effect of shear rate and oxygen transfer on clavulanic acid production by Streptomyces clavuligerus.

The production of biocompounds through the cultivation of filamentous microorganisms is mainly affected by Oxygen Transfer Rate (OTR) and shear rate ([Formula: see text]) conditions. Despite efforts have been made to evaluate the effect of operating variables (impeller speed, N; and airflow rate, ϕair) on clavulanic acid production, no analysis regarding the effect of OTR and [Formula: see text] was made. Then, the aim of this study was to evaluate the dissociated effect of physical phenomena such as oxygen transfer and shear rate in the production of clavulanic acid from Streptomyces clavuligerus using a stirred tank bioreactor. Streptomyces clavuligerus cultivations were performed at five different OTR and [Formula: see text] conditions by manipulating the operating conditions (N, ϕair, and gas inlet composition). Cultivations performed at equal impeller speed (600 rpm, similar [Formula: see text]) using oxygen enrichment, showed that CA productivity (ProdCA) was positively affected by OTR increase. Subsequently, the different shear conditions (achieved by varying the impeller speed) lead to an increase in CA production levels. Despite both OTR and shear rate positively enhanced CA productivity, [Formula: see text] exhibited the highest impact: an increase of 145% in OTRinitial enhanced the clavulanic acid productivity of about 29%, while an increment in the shear rate of 134% raised the ProdCA in 53%.

Fluorescent probes for the detection of reactive oxygen species in human spermatozoa.

Reactive oxygen species (ROS) production is a by-product of mitochondrial activity and is necessary for the acquisition of the capacitated state, a requirement for functional spermatozoa. However, an increase in oxidative stress, due to an abnormal production of ROS, has been shown to be related to loss of sperm function, highlighting the importance of an accurate detection of sperm ROS, given the specific nature of this cell. In this work, we tested a variety of commercially available fluorescent probes to detect ROS and reactive nitrogen species (RNS) in human sperm, to define their specificity. Using both flow cytometry (FC) and fluorescence microscopy (FM), we confirmed that MitoSOX™ Red and dihydroethidium (DHE) detect superoxide anion (as determined using antimycin A as a positive control), while DAF-2A detects reactive nitrogen species (namely, nitric oxide). For the first time, we also report that RedoxSensor™ Red CC-1, CellROX® Orange Reagent, and MitoPY1 seem to be mostly sensitive to hydrogen peroxide, but not superoxide. Furthermore, mean fluorescence intensity (and not percentage of labeled cells) is the main parameter that can be reproducibly monitored using this type of methodology.

Pathogen reduction of blood components during outbreaks of infectious diseases in the European Union: an expert opinion from the European Centre for Disease Prevention and Control consultation meeting.

Pathogen reduction (PR) of selected blood components is a technology that has been adopted in practice in various ways. Although they offer great advantages in improving the safety of the blood supply, these technologies have limitations which hinder their broader use, e.g. increased costs. In this context, the European Centre for Disease Prevention and Control (ECDC), in co-operation with the Italian National Blood Centre, organised an expert consultation meeting to discuss the potential role of pathogen reduction technologies (PRT) as a blood safety intervention during outbreaks of infectious diseases for which (in most cases) laboratory screening of blood donations is not available. The meeting brought together 26 experts and representatives of national competent authorities for blood from thirteen European Union and European Economic Area (EU/EEA) Member States (MS), Switzerland, the World Health Organization, the European Directorate for the Quality of Medicines and Health Care of the Council of Europe, the US Food and Drug Administration, and the ECDC. During the meeting, the current use of PRTs in the EU/EEA MS and Switzerland was verified, with particular reference to emerging infectious diseases (see Appendix). In this article, we also present expert discussions and a common view on the potential use of PRT as a part of both preparedness and response to threats posed to blood safety by outbreaks of infectious disease.

Ion Fluxes through KCa2 (SK) and Cav1 (L-type) Channels Contribute to Chronoselectivity of Adenosine A1 Receptor-Mediated Actions in Spontaneously Beating Rat Atria.

Impulse generation in supraventricular tissue is inhibited by adenosine and acetylcholine via the activation of A1 and M2 receptors coupled to inwardly rectifying GIRK/KIR3.1/3.4 channels, respectively. Unlike M2 receptors, bradycardia produced by A1 receptors activation predominates over negative inotropy. Such difference suggests that other ion currents may contribute to adenosine chronoselectivity. In isolated spontaneously beating rat atria, blockade of KCa2/SK channels with apamin and Cav1 (L-type) channels with nifedipine or verapamil, sensitized atria to the negative inotropic action of the A1 agonist, R-PIA, without affecting the nucleoside negative chronotropy. Patch-clamp experiments in the whole-cell configuration mode demonstrate that adenosine, via A1 receptors, activates the inwardly-rectifying GIRK/KIR3.1/KIR3.4 current resulting in hyperpolarization of atrial cardiomyocytes, which may slow down heart rate. Conversely, the nucleoside inactivates a small conductance Ca(2+)-activated KCa2/SK outward current, which eventually reduces the repolarizing force and thereby prolong action potentials duration and Ca(2+) influx into cardiomyocytes. Immunolocalization studies showed that differences in A1 receptors distribution between the sinoatrial node and surrounding cardiomyocytes do not afford a rationale for adenosine chronoselectivity. Immunolabelling of KIR3.1, KCa2.2, KCa2.3, and Cav1 was also observed throughout the right atrium. Functional data indicate that while both A1 and M2 receptors favor the opening of GIRK/KIR3.1/3.4 channels modulating atrial chronotropy, A1 receptors may additionally restrain KCa2/SK activation thereby compensating atrial inotropic depression by increasing the time available for Ca(2+) influx through Cav1 (L-type) channels.

Efficacy in the treatment of malaria by Plasmodium vivax in Oiapoque, Brazil, on the border with French Guiana: the importance of control over external factors.

BACKGROUND: Plasmodium vivax malaria is an important public health issue in the Amazon region, and it accounts for approximately 84 % of cases of the disease. Migration across the border between Brazil and French Guiana contributes to the maintenance of the disease. The aim of this study was to evaluate the therapeutic and parasitological responses of patients with P. vivax malaria treated with chloroquine and primaquine in the socio-environmental context of cross-border interactions between Brazil and French Guiana. The factors controlled were diagnostic agreement, adherence, adjustment of primaquine doses for patient weight, and quality of the drugs used. METHODS: A prospective study was conducted in 2011 with 103 individuals aged 10-60 years with a positive diagnosis of P. vivax treated with chloroquine (10 mg base/kg on the first day, followed by 7.5 mg/kg on the second and third days) and primaquine for 7 days, who were followed for 28 days. The primaquine doses were adjusted for the patients' weight. A number of factors were determined: epidemiological characteristics, origin of patients, signs and symptoms, initial parasitaemia and parasitaemia clearance time, blood concentrations of chloroquine and primaquine, quality of anti-malarial drugs and diagnostic agreement. RESULTS: Ninety-five patients were followed for 28 days. There was a 100 % agreement in microscopic diagnosis between field laboratory and reference centre. The adhesion to the treatment was 100 %. Of these patients, 32.6 % received a weight-adjusted dose of primaquine. The chloroquine and primaquine tablets were consistent with the optimal quality limits for human consumption. The investigated patients achieved optimal blood exposure to anti-malarial drugs. The parasitological and therapeutic response was adequate in 99.0 % of cases. CONCLUSIONS: In the municipality of Oiapoque, the therapeutic regime used for the treatment of P. vivax malaria using chloroquine combined with primaquine remains effective, when external factors are controlled, such as the quality of anti-malarial drugs, the adhesion to the treatment prescribed, the correct diagnostic and the adjustment of primaquine dose for patient body weight.

Actin-interacting and flagellar proteins in Leishmania spp.: Bioinformatics predictions to functional assignments in phagosome formation.

Several motile processes are responsible for the movement of proteins into and within the flagellar membrane, but little is known about the process by which specific proteins (either actin-associated or not) are targeted to protozoan flagellar membranes. Actin is a major cytoskeleton protein, while polymerization and depolymerization of parasite actin and actin-interacting proteins (AIPs) during both processes of motility and host cell entry might be key events for successful infection. For a better understanding the eukaryotic flagellar dynamics, we have surveyed genomes, transcriptomes and proteomes of pathogenic Leishmania spp. to identify pertinent genes/proteins and to build in silico models to properly address their putative roles in trypanosomatid virulence. In a search for AIPs involved in flagellar activities, we applied computational biology and proteomic tools to infer from the biological meaning of coronins and Arp2/3, two important elements in phagosome formation after parasite phagocytosis by macrophages. Results presented here provide the first report of Leishmania coronin and Arp2/3 as flagellar proteins that also might be involved in phagosome formation through actin polymerization within the flagellar environment. This is an issue worthy of further in vitro examination that remains now as a direct, positive bioinformatics-derived inference to be presented.

Actin-interacting and flagellar proteins in Leishmania spp: bioinformatics predictions to functional assignments in phagosome formation

Several motile processes are responsible for the movement of proteins into and within the flagellar membrane, but little is known about the process by which specific proteins (either actin-associated or not) are targeted to protozoan flagellar membranes. Actin is a major cytoskeleton protein, while polymerization and depolymerization of parasite actin and actin-interacting proteins (AIPs) during both processes of motility and host cell entry might be key events for successful infection. For a better understanding the eukaryotic flagellar dynamics, we have surveyed genomes, transcriptomes and proteomes of pathogenic Leishmania spp. to identify pertinent genes/proteins and to build in silico models to properly address their putative roles in trypanosomatid virulence. In a search for AIPs involved in flagellar activities, we applied computational biology and proteomic tools to infer from the biological meaning of coronins and Arp2/3, two important elements in phagosome formation after parasite phagocytosis by macrophages. Results presented here provide the first report of Leishmania coronin and Arp2/3 as flagellar proteins that also might be involved in phagosome formation through actin polymerization within the flagellar environment. This is an issue worthy of further in vitro examination that remains now as a direct, positive bioinformatics-derived inference to be presented.