Effects of dopamine on ion transport across rat colon

Dopamine (5.10-6 – 5.10-4 mol.l-1) when added serosally induced a concentrationdependent decrease in short-circuit current (Isc) across rat distal and proximal colon. This response was preceded by a transient and inconsistent increase in Isc. A part of the catecholamine action is mediated by subepithelial actions sites as it was indicated by the inhibiton of dopamine effects by the cyclooxygenase inhibitor, indomethacin (10-6 mol.l-1), and the neuronal blocker, tetrodotoxin (10-6 mol.l-1). The positive Isc evoked by dopamine was due to chloride secretion as indicated when both Cl- and HCO3- were substituted (using HEPES as buffer) and when of the basolateral membrane was depolarizing by high potassium concentration. The negative Isc evoked by dopamine was due to potassium secretion. This was demonstrated by unidirectional flux experiments. 86Rb+ efflux experiments revealed a redistribution of cellular K+ efflux in favour of the apical K+ conductance in the presence of dopamine. The negative Isc evoked by dopamine was inhibited by the blocker of apical K+ channels, quinine (10-3 mol.l-1), indicating that a stimulation of K+ secretion underlies the measured current. Both the alpha-adrenoceptor blocker phentolamine (10-4 mol.l-1) and as well as inhibitors of D2-like receptors such as L-741,626 (10-5 mol.l-1) and L-745,870 (10-5 mol.l-1) inhibited the dopamine response. All these observations indicate similarities between dopamine and the other catecholamines derivatives in their effect on ions transport in rat colon

The level of utilizing blended learning in teaching science from the point of view of science teachers in private schools of Ajman Educational Zone

This study aims to define the level of utilizing blended learning in teaching science from the point of view of science teachers (85 male and female teachers) who are working in private schools of Ajman Educational Zone. The study also aims to find if there are significant differences according to gender, years of experience, or the fact that those teachers attended training courses in the field of smart learning. To achieve the goals of this study, an instrument was used to measure the level of utilizing blended learning in teaching science. The study showed the following main results: the level of utilizing blended learning in teaching science was high. There are statistically significant differences in utilizing blended learning according to the years of experience and training courses (in favor of less experienced teachers and teachers who attended training courses in the field of smart learning). The results did not show any statistically significant difference according to the gender. In the light of the study findings and their interpretation, the study highly recommends holding training courses in the field of blended learning and providing the necessary tools to implement it. Key words: Blended learning, science teachers, science educatio

Rodent models of neuroinflammation for Alzheimer\u27s disease

Alzheimer\u27s disease remains incurable, and the failures of current disease-modifying strategies for Alzheimer\u27s disease could be attributed to a lack of in vivo models that recapitulate the underlying etiology of late-onset Alzheimer\u27s disease. The etiology of late-onset Alzheimer\u27s disease is not based on mutations related to amyloid-beta (A beta) or tau production which are currently the basis of in vivo models of Alzheimer\u27s disease. It has recently been suggested that mechanisms like chronic neuroinflammation may occur prior to amyloid-beta and tau pathologies in late-onset Alzheimer\u27s disease. The aim of this study is to analyze the characteristics of rodent models of neuroinflammation in late-onset Alzheimer\u27s disease. Our search criteria were based on characteristics of an idealistic disease model that should recapitulate causes, symptoms, and lesions in a chronological order similar to the actual disease. Therefore, a model based on the inflammation hypothesis of late-onset Alzheimer\u27s disease should include the following features: (i) primary chronic neuroinflammation, (ii) manifestations of memory and cognitive impairment, and (iii) late development of tau and A beta pathologies. The following models fit the pre-defined criteria: lipopolysaccharide-and PolyI:C-induced models of immune challenge; streptozotocin-, okadaic acid-, and colchicine neurotoxin-induced neuroinflammation models, as well as interleukin-1 beta, anti-nerve growth factor and p25 transgenic models. Among these models, streptozotocin, PolyI:C-induced, and p25 neuroinflammation models are compatible with the inflammation hypothesis of Alzheimer\u27s disease

A Novel Mechanism of B Cell-Mediated Immune Suppression through CD73 Expression and Adenosine Production

Immune suppression by regulatory T cells and regulatory B cells is a critical mechanism to limit excess inflammation and autoimmunity. IL-10 is considered the major mediator of B cell induced immune suppression. We report a novel mechanism for immune suppression through adenosine generation by B cells. We identified a novel population of B cells that expresses CD73 as well as CD39, two ectoenzymes that together catalyze the extracellular dephosphorylation of adenine nucleotides to adenosine. Whereas CD39 expression is common among B cells, CD73 expression is not. Approximately 30-50% of B-1 cells (B220(+)CD23(-)) and IL-10 producing B (B10) cells (B220(+)CD5(+)CD1d(hi)) are CD73111, depending on mouse strain, whereas few conventional B-2 cells (B220+CD23+AA4.1) express CD73. In keeping with expression of both CD73 and CD39, we found that CD73(+) B cells produce adenosine in the presence of substrate, whereas B-2 cells do not. CD73(-/-) mice were more susceptible to dextran sulfate sodium salt (DSS)-induced colitis than wild type (WT) mice were, and transfer of CD73+ B cells ameliorated the severity of colitis, suggesting that B cell CD73/CD39/adenosine can modulate DSS-induced colitis. IL-10 production by B cells is not affected by CD73 deficiency. Interestingly, adenosine generation by IL-10(-/-) B cells is impaired because of reduced expression of CD73, indicating an unexpected connection between IL-10 and adenosine and suggesting caution in interpreting the results of studies with IL-10(-/-) cells. Our findings demonstrate a novel regulatory role of B cells on colitis through adenosine generation in an IL10 independent manner

SARS-CoV-2 and interferon blockade

© 2020, The Author(s). The response to viral infection generally includes an activation of the adaptive immune response to produce cytotoxic T cells and neutralizing antibodies. We propose that SARS-CoV-2 activates the innate immune system through the renin-angiotensin and kallikrein-bradykinin pathways, blocks interferon production and reduces an effective adaptive immune response. This model has therapeutic implications

Correction to: Exploring the biological functional mechanism of the HMGB1/TLR4/MD-2 complex by surface plasmon resonance.

After publication of this article (He et al., 2018), the corresponding authors recognised an error in Scheme 1, in particular to section A. HMGB1/TLR4/MD-2 complex formation . Above Step 2: B box binding to MD-2 , the text incorrectly read: Low affinity / extremely slow off . In addition, some text was omitted below TLR4/MD-2 . The correct version of Scheme 1 is included in this Correction article. The original article (He et al., 2018) has been corrected

EVALUATION OF OAT VARIETIES UNDER SUFFICIENT AND INSUFFICIENT IRRIGATION

This study was aimed to investigate the genetic variations of Oat cultivars under in sufficient of irrigation. A field experiment was carried out at the fields of with  College of Agricultural Engineering Sciences ;University of Baghdad - Al-Jadriya during 2020-2021 seasons. The experiment was carried out using a Completely Block designwithin split-plot arrangement using three replicates under two treatments (verities and irrigation intervals). The main plots were irrigation intervals with moisture(50%, 25%, and 10%), while sub-plots were the varieties (Genzania, Anatolia, Plmula, Algoda, and Al-Shifa).The results showed that the third irrigation level had 75% flowering at highest averages93.67 days , and the V4 variety had the  lowest average to  weight of 250 grains about (7.67 g ).While there was a significant differencesamong  irrigation interval 75% flowering compared with other traits  ( 22.8) ,(24.6  )and ( 7.75) respectively. While the Alogoda produced the highest yield (7.49 ton .h-1) compared with the lowest Plmula gave (5.83 ton h-1)There are differences among of varieties under irrigation intervals. The highest genotypic coefficient to yield (94.7%) and the highest value of heritability was (98.75%).to the flowering