Macrocyclic lactones: distribution in plasma lipoproteins of several animal species including humans

We studied the in vitro distribution of macrocyclic lactones (MLs), lipophilic anthelmintic drugs, in the plasma of several animal species including humans. First, in vitro spiking of goat plasma was performed with ivermectin, moxidectin, abamectin, doramectin, or eprinomectin. In parallel, goats were treated with subcutaneous injection of ivermectin. Then, cow, sheep, rabbit, pig, and human plasma were spiked with moxidectin. Four fractions were separated using KBr density gradient ultracentrifugation: very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and lipoprotein-deficient fraction. Cholesterol was analyzed by enzymatic assay and MLs by high-performance liquid chromatography. An average of 96% of MLs was associated with lipoproteins. The five MLs studied distributed similarly into goat plasma fractions with a preferential association with HDL (80-90%). Ivermectin partitioning in goat plasma was similar after in vitro spiking and in vivo treatment. In species displaying various lipoprotein profiles, moxidectin was also mainly associated with HDL. However, in human plasma, moxidectin was associated with a lesser extent to HDL (70%) and more to LDL (22%) when compared to other animal species. A relation between the plasma cholesterol content and pharmacokinetics of the drug is suggested. Our finding will allow further exploration of intestinal lymphatic absorption and milk elimination of these compounds-mechanisms in which lipoproteins are involved. In addition, possible improvements of new drug delivery systems are suggested.     

Epileptic Discharges Affect the Default Mode Network – fMRI and Intracerebral EEG Evidence

Functional neuroimaging studies of epilepsy patients often show, at the time of epileptic activity, deactivation in default mode network (DMN) regions, which is hypothesized to reflect altered consciousness. We aimed to study the metabolic and electrophysiological correlates of these changes in the DMN regions. We studied six epilepsy patients that underwent scalp EEG-fMRI and later stereotaxic intracerebral EEG (SEEG) sampling regions of DMN (posterior cingulate cortex, Pre-cuneus, inferior parietal lobule, medial prefrontal cortex and dorsolateral frontal cortex) as well as non-DMN regions. SEEG recordings were subject to frequency analyses comparing sections with interictal epileptic discharges (IED) to IED-free baselines in the IED-generating region, DMN and non-DMN regions. EEG-fMRI and SEEG were obtained at rest. During IEDs, EEG-fMRI demonstrated deactivation in various DMN nodes in 5 of 6 patients, most frequently the pre-cuneus and inferior parietal lobule, and less frequently the other DMN nodes. SEEG analyses demonstrated decrease in gamma power (50–150 Hz), and increase in the power of lower frequencies (<30 Hz) at times of IEDs, in at least one DMN node in all patients. These changes were not apparent in the non-DMN regions. We demonstrate that, at the time of IEDs, DMN regions decrease their metabolic demand and undergo an EEG change consisting of decreased gamma and increased lower frequencies. These findings, specific to DMN regions, confirm in a pathological condition a direct relationship between DMN BOLD activity and EEG activity. They indicate that epileptic activity affects the DMN, and therefore may momentarily reduce the consciousness level and cognitive reserve.     

Une syringocèle révélée par un abcès périntéal

Purpose

The authors present a clinical report of a perforate syringocele diagnosed in a male patient and they review the clinical, radiological and therapeutic aspects of this disease.

Case report

A 50-year-old man attended the emergency room with perineal abscess. Computerized Tomography (CT) scan was used to establish the diagnosis. This patient also underwent urethrocystoscopy, sonography and retrograde urethrography.

Results

Treatment consisted of open surgical evacuation of the perineal abscess with bladder catheter. Urethrocystoscopy showed a large perforate syringocele in the urethra with no need for endoscopy marsupialization. No recurrence was observed at follow-up at 3 months.

Conclusion

Syringocele is a rare malformation which usually is asymptomatic. It can be congenital or acquired and can be classified into four morphological types. The most frequent treatment is endoscopic marsupialization of the syringocèle. Open surgical excision is recommended for complicated syringocèle with abscess or perineal pain.     

Optimization of conditions for germination of cold-stored <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> pollen

One of the rare weak points of the model plant Arabidopsis is the technical problem associated with the germination of its male gametophyte and the generation of the pollen tube in vitro. Arabidopsis pollen being tricellular has a notoriously low in vitro germination compared to species with bicellular pollen. This drawback strongly affects the reproducibility of experiments based on this cellular system. Together with the fact that pollen collection from this species is tedious, these are obstacles for the standard use of Arabidopsis pollen for experiments that require high numbers of pollen tubes and for which the percentage of germination needs to be highly reproducible. The possibility of freeze-storing pollen after bulk collection is a potential way to solve these problems, but necessitates methods that ensure continued viability and reproducible capacity to germinate. Our objective was the optimization of germination conditions for Arabidopsis pollen that had been freeze-stored. We optimized the concentrations of various media components conventionally used for in vitro pollen germination. We found that in general 4 mM calcium, 1.62 mM boric acid, 1 mM potassium, 1 mM magnesium, 18% sucrose at pH 7 and a temperature of 22.5°C are required for optimal pollen germination. However, different experimental setups may deviate in their requirements from this general protocol. We suggest how to optimally use these optimized methods for different practical experiments ranging from morphological observations of pollen tubes in optical and electron microscopy to their bulk use for molecular and biochemical analyses or for experimental setups for which a specific medium stiffness is critical. F. Bou Daher and Y. Chebli contributed equally to this study.     

The Association of Systemic Microvascular Changes with Lung Function and Lung Density: A Cross-Sectional Study

Smoking causes endothelial dysfunction and systemic microvascular disease with resultant end-organ damage in the kidneys, eyes and heart. Little is known about microvascular changes in smoking-related lung disease. We tested if microvascular changes in the retina, kidneys and heart were associated with obstructive spirometry and low lung density on computed tomography. The Multi-Ethnic Study of Atherosclerosis recruited participants age 45–84 years without clinical cardiovascular disease. Measures of microvascular function included retinal arteriolar and venular caliber, urine albumin-to-creatinine ratio and, in a subset, myocardial blood flow on magnetic resonance imaging. Spirometry was measured following ATS/ERS guidelines. Low attenuation areas (LAA) were measured on lung fields of cardiac computed tomograms. Regression models adjusted for pulmonary and cardiac risk factors, medications and body size. Among 3,397 participants, retinal venular caliber was inversely associated with forced expiratory volume in one second (FEV₁) (P<0.001) and FEV₁/forced vital capacity (FVC) ratio (P = 0.04). Albumin-to-creatinine ratio was inversely associated with FEV₁ (P = 0.002) but not FEV₁/FVC. Myocardial blood flow (n = 126) was associated with lower FEV₁ (P = 0.02), lower FEV₁/FVC (P = 0.001) and greater percentage LAA (P = 0.04). Associations were of greater magnitude among smokers. Low lung function was associated with microvascular changes in the retina, kidneys and heart, and low lung density was associated with impaired myocardial microvascular perfusion. These cross-sectional results suggest that microvascular damage with end-organ dysfunction in all circulations may pertain to the lung, that lung dysfunction may contribute to systemic microvascular disease, or that there may be a shared predisposition.     

mvaT mutation modifies the expression of the Pseudomonas aeruginosa multidrug efflux operon mexEF-oprN

Pseudomonas aeruginosa carries several multidrug efflux operons, including mexEF-oprN, that contribute to its resistance to multiple antibiotics. mvaT affects the expression of several P. aeruginosa genes. In this study, we show that the mvaT mutant PAODeltamvaT is more resistant than its parent PAO1 strain to chloramphenicol and norfloxacin but more sensitive to imipenem; yet both were less resistant to chloramphenicol, norfloxacin, and imipenem than 'typical'nfxC-type mutants. Neither strain carries the deletion described for nfxC-type mutants in mexT, the mexEF-oprN regulatory gene. Expression of mexEF-oprN is increased by five- to sixfold in PAODeltamvaT, while the expression of oprD is reduced by approximately twofold. mvaT mutation had no effect on the expression of other multidrug resistance operons, although it increased the expression of several ATP-binding cassette transporter genes. We show that mvaT mutation does not affect mexEF-oprN expression through mexT or mexS. We also explored several other potential mechanisms.     

The Effect of Chronic Methamphetamine Exposure on the Hippocampal and Olfactory Bulb Neuroproteomes of Rats

Nowadays, drug abuse and addiction are serious public health problems in the USA. Methamphetamine (METH) is one of the most abused drugs and is known to cause brain damage after repeated exposure. In this paper, we conducted a neuroproteomic study to evaluate METH-induced brain protein dynamics, following a two-week chronic regimen of an escalating dose of METH exposure. Proteins were extracted from rat brain hippocampal and olfactory bulb tissues and subjected to liquid chromatography-mass spectrometry (LC-MS/MS) analysis. Both shotgun and targeted proteomic analysis were performed. Protein quantification was initially based on comparing the spectral counts between METH exposed animals and their control counterparts. Quantitative differences were further confirmed through multiple reaction monitoring (MRM) LC-MS/MS experiments. According to the quantitative results, the expression of 18 proteins (11 in the hippocampus and 7 in the olfactory bulb) underwent a significant alteration as a result of exposing rats to METH. 13 of these proteins were up-regulated after METH exposure while 5 were down-regulated. The altered proteins belonging to different structural and functional families were involved in processes such as cell death, inflammation, oxidation, and apoptosis.     

Global Renal Gene Expression Profiling Analysis in B2-Kinin Receptor Null Mice: Impact of Diabetes

Diabetic nephropathy (DN), the leading cause of end-stage renal failure, is clinically manifested by albuminuria and a progressive decline in glomerular filtration rate. The risk factors and mechanisms that contribute to the development and progression of DN are still incompletely defined. To address the involvement of bradykinin B₂-receptors (B₂R) in DN, we used a genome wide approach to study the effects of diabetes on differential renal gene expression profile in wild type and B₂R knockout (B₂R^−/−) mice. Diabetes was induced with streptozotocin and plasma glucose levels and albumin excretion rate (AER) were measured at predetermined times throughout the 23 week study period. Longitudinal analysis of AER indicated that diabetic B₂R^−/−D null mice had a significantly decreased AER levels compared to wild type B₂R^+/+D mice (P = 0.0005). Results from the global microarray study comparing gene expression profiles among four groups of mice respectively: (B₂R^+/+C, B₂R^+/+D, B₂R^−/−C and B₂R^−/−D) highlighted the role of several altered pathological pathways in response to disruption of B₂R and to the diabetic state that included: endothelial injury, oxidative stress, insulin and lipid metabolism and inflammatory process with a marked alteration in the pro-apoptotic genes. The findings of the present study provide a global genomics view of biomarkers that highlight the mechanisms and putative pathways involved in DN.