Regional expression and ultrastructural localization of EphA7 in the hippocampus and cerebellum of adult rat

EphA7 is expressed in the adult central nervous system (CNS), where its roles are yet poorly defined. We mapped its distribution using in situ hybridization (ISH) and immunohistochemistry (IHC) combined with light (LM) and electron microscopy (EM) in adult rat and mouse brain. The strongest ISH signal was in the hippocampal pyramidal and granule cell layers. Moderate levels were detected in habenula, striatum, amygdala, the cingulate, piriform and entorhinal cortex, and in cerebellum, notably the Purkinje cell layer. The IHC signal distribution was consistent with ISH results, with transport of the protein to processes, as exemplified in the hippocampal neuropil layers and weakly stained pyramidal cell layers. In contrast, in the cerebellum, the Purkinje cell bodies were the most strongly immunolabeled elements. EM localized the cell surface‐expression of EphA7 essentially in postsynaptic densities (PSDs) of dendritic spines and shafts, and on some astrocytic leaflets, in both hippocampus and cerebellum. Perikaryal and dendritic labeling was mostly intracellular, associated with the synthetic and trafficking machineries. Immunopositive vesicles were also observed in axons and axon terminals. Quantitative analysis in EM showed significant differences in the frequency of labeled elements between regions. Notably, labeled dendrites were ～3–5 times less frequent in cerebellum than in hippocampus, but they were individually endowed with ～10–40 times higher frequencies of PSDs, on their shafts and spines. The cell surface localization of EphA7, being preferentially in PSDs, and in perisynaptic astrocytic leaflets, provides morphologic evidence that EphA7 plays key roles in adult CNS synaptic maintenance, plasticity, or function. J. Comp. Neurol. 524:2462–2478, 2016. © 2016 Wiley Periodicals, Inc.     

Cyanobacterial extracts containing microcystins affect the growth,nodulation process and nitrogen uptake of faba bean (<Emphasis Type="Italic">Vicia faba</Emphasis> L., Fabaceae)

The use of irrigation water containing cyanobacterial toxins may generate a negative impact in both yield and quality of agricultural crops causing significant economic losses. We evaluated the effects of microcystins (MC) on the growth, nodulation process and nitrogen uptake of a Faba bean cultivar (Vicia faba L., Fabaceae), particularly the effect of MC on rhizobia-V. faba symbiosis. Three rhizobial strains (RhOF4, RhOF6 and RhOF21), isolated from nodules of local V. faba were tested. The exposure of rhizobia to MC showed that the toxins had a negative effect on the rhizobial growth especially at the highest concentrations of 50 and 100 μg/l. The germination of faba bean seeds was also affected by cyanotoxins. We registered germination rates of 75 and 68.75% at the toxin levels of 50 and 100 μg/l as compared to the control (100%). The obtained results also showed there was a negative effect of MC on plants shoot, root (dry weight) and total number of nodules per plant. Cyanotoxins exposure induced a significant effect on nitrogen assimilation by faba bean seedlings inoculated with selected rhizobial strains RhOF6 and RhOF21, while the effect was not significant on beans seedling inoculated with RhOF4. This behavior of tolerant rhizobia-legumes symbioses may constitute a very important pathway to increase soil fertility and quality and can represent a friendly biotechnological way to remediate cyanotoxins contamination in agriculture.     

Influence of mutation of the HFE gene on the progression of chronic viral hepatitis B and C in Moroccan patients

The implication of hemochromatosis (HFE) gene mutations in chronic viral hepatitis remains controversial. The aim of the present study was to measure the frequencies of the common HFE gene mutations in Moroccan subjects with chronic viral hepatitis B and C and to assess their influence on the progression of liver disease. H63D and C282Y mutations were screened by the polymerase chain reaction followed by restriction fragment length polymorphism analysis in 170 chronic hepatitis B patients, 168 chronic hepatitis C patients, and 200 healthy controls. A very small proportion of patients infected with hepatitis B virus (HBV) or hepatitis C virus (HCV; 1.8% and none, respectively) were heterozygous for the C282Y mutation, that is, rates not statistically different from those observed in healthy control (2%, P > 0.05). Similarly, the frequency of the H63D allele was not significantly different between HBV (13.8%) or HCV (14.3%) patients and controls (13.5%, P > 0.05). Multivariate analysis showed that carriers of the H63D mutation infected with HBV are at higher risk to progress towards an advanced liver disease when compared with patients infected with HBV with wild‐type (OR = 2.45, 95% CI = 1.07–5.58). In contrast, no association between HFE mutated HCV‐infected patients and an increased risk of disease progression was found (OR = 1.24, 95% CI = 0.61–2.50, P = 0.547). In conclusion, in Morocco the frequency of the HFE C282Y allele is very low and H63D mutation carriage occurs in almost 14% of the patients, a rate similar in chronic hepatitis patients and healthy controls. In the case of chronic hepatitis B, the carriage of the H63D variant represents a risk factor of evolution towards a more active disease. J. Med. Virol. 83:2096–2102, 2011. © 2011 Wiley Periodicals, Inc.     

Acute hypertension in intracerebral hemorrhage: pathophysiology and treatment

Non-traumatic or spontaneous intracerebral hemorrhage (ICH) is defined as intra-parenchymal bleeding with or without extension into the ventricles and rarely into the subarachoid space. Primary ICH in most cases is associated with chronic hypertension. Acute hypertension is associated with hematoma expansion, and poor neurological outcome. The treatment of hypertension in acute ICH is a topic of controversy. Experiments have shown an area of ischemia around the hematoma, with the reduction of regional cerebral blood flow (CBF) secondary to compression of microvasculature. Not all scientific results agree with the above findings. Recent studies have shown that CBF decreases in the perihematoma region but with concomitant reduction of cerebral metabolism, which would argue against an area of ischemia in the perihematoma region. Based on the above result, there have been several clinical trials looking at clinical outcome and decrease in hematoma expansion rates with reduction of blood pressure acutely after ICH. The parameters for the blood pressure control are still under investigation. The American Heart Association has put forward guidelines for blood pressure control which have been adopted in the centers around the country. We have described the protocol we use at our center for the blood pressure control in patients with acute ICH.     

Linear quantitation of Abeta aggregation using Thioflavin T: reduction in fibril formation by colostrinin

Thioflavin T (ThT) fluorescence is a commonly used method to monitor Aβ protein fibril formation. This method is particularly attractive since ThT fluoresces only when bound to fibrils, the reaction is completed within 1 min and ThT does not interfere with aggregation of Aβ fibrils. One of the drawbacks of this method is the lack of a strict quantitative relationship between ThT fluorescence and fibril content. It was observed that, when the same gram molecular weight of Aβ (1–40) is dissolved into varying amounts of base then placed into a constant volume of aqueous buffer, a non-linear fluorescent response is obtained. By maintaining a strict relationship between Aβ content and the volume of base, this anomalous result can be alleviated and a linear dose response curve is obtained at much lower Aβ concentrations than is typically observed.

In addition, differences in Aβ batch to batch preparations are alleviated. It was previously reported that colostrinin (CLN), a proline-rich peptide derived from colostrum, reduces fibril content and protects neuroblastoma cells against Aβ peptide-induced toxicity. The newly developed ThT fluorescence protocol was used to quantify Aβ fibril content after treatment with CLN. We also demonstrate that CLN, can solubilize Aβ fibrils in a dose and time-dependent fashion.