Pre-Administration of Medium Chain Triglycerides In Vivo Can Attenuate or Block the Effects of Recurrent Hypoglycemia

Hypoglycemia is a state of abnormally low blood glucose. Many patients who use insulin, primarily for the treatment of diabetes, experience multiple bouts of hypoglycemia, termed recurrent hypoglycemia (RH). Because RH impairs cognitive function and ability to appropriately respond to a subsequent episode of hypoglycemia, it is critical to develop treatments. One approach, which we have taken here, is to attempt to preserve neuronal fuel supply during a hypoglycemic episode. Medium-chain triglycerides are medium-chain fatty acid (MCT) esters of glycerol that can provide an alternative fuel source to the brain via ketones; the hippocampus is known to express transporters for ketones and to be able to metabolize them. Hence, pre-administration of MCT prior to times of hypoglycemia could possibly prevent the deleterious effects of RH if they are due to loss of fuel generically rather than to specific loss of glucose. We have used a previously established three-day rat model of RH, in which rats are made hypoglycemic on each of three consecutive days and show both cognitive effects and impaired responses to hypoglycemia on the 4th day. Here, we gave Sprague-Dawley rats MCT (i.p.) prior to each episode of hypoglycemia, followed by cognitive testing, removal of the brain and analysis of brain proteins of interest: transporters for glucose and ketones as well as additional markers suggested by our prior studies. During cognitive testing, in vivo microdialysis was used to obtain real-time measures of hippocampal glucose and lactate; previous work showed that RH markedly affected local hippocampal metabolism during testing

Italian Map of Design Earthquakes from Multimodal Disaggregation Distributions: Preliminary Results.

Probabilistic seismic hazard analysis allows to calculate the mean annual rate of exceedance of ground motion intensity measures given the seismic sources the site of interest is subjected to. This piece of information may be used to define the design seismic action on structures. Moreover, through disaggregation of seismic hazard, it is possible to identify the earthquake giving the largest contribution to the hazard related to a specific IM value. Such an information may also be of useful to engineers in better defining the seismic treat for the structure of interest (e.g., in record selection for nonlinear seismic structural analysis). On the other hand, disaggregation results change with the spectral ordinate and return period, and more than a single event may dominate the hazard, especially if multiple sources affect the hazard at the site. In this work disaggregation for structural periods equal to 0 sec and 1.0 sec is presented for Italy, with reference to the hazard with a 475 year return period. It will be discussed how for the most of Italian sites more than a design earthquake exist, because of the modelling of seismic sources

EFFECT OF NIRGUNDI (VITEX NEGUNDO LINN.) PATRA ARKA AS ASCHOTHANA (EYE DROPS) IN CATARACT-A CLINICAL STUDY

Purpose: Age-related cataract is one of the leading causes of blindness and avoidable visual impairment in the world. There is no time-tested, FDA-approved, or clinically proven medical treatment exists till date to delay, prevent, or reverse the progression of senile cataract. Nirgundi (Vitex negundo) is a Chakshushya single drug mentioned in Ayurvedic classics. Various animal experimental study and invitro studies in recent years using flavonoids extracted from leaves of Vitex negundo on selenite induced cataract models proved to be beneficial in arresting the progression of cataract. Hence a clinical study with Vitex negundo eye drops in the form of Arka was planned with primary objective to assess the effect of Nirgundi patra arka as Aschotana (eye drops) in pre senile cataract. Methods: The study design was interventional pre and post evaluation without control. Patients were advised to instill Nirgundi patra arka two drops thrice daily i.e. 6 am, 12 pm and 6pm for a period of 6months. Log mar visual acuity score and contrast sensitivity score were recorded before treatment, 3rd month of treatment, after treatment, 9th month (1st follow up) and 12th month (2nd follow up). Slit lamp photographs were recorded before treatment and 12th month. Study and follow up were done in 31 eyes. Result: The intervention is statistically significant while considering visual acuity and contrast sensitivity. All the 27 cases of nuclear cataract responded to the intervention, while only 83.3% of posterior sub capsular cataract and 60% of cortical cataract showed response. But the change was not significant statistically. Conclusion: The intervention was effective in improving visual acuity and contrast sensitivity in all types of pre senile cataract. Clinical assessment revealed the study was effective in preventing the progression of pathogenesis in early stage of nuclear cataract

DIALYSIS PRACTICE PATTERN IN PATIENTS UNDERGOING HEMODIALYSIS IN A TERTIARY AND A PRIVATE HOSPITAL

Objective: To evaluate the dialysis practice pattern in chronic kidney disease patients undergoing hemodialysis in a tertiary and a private hospital Methods: A prospective observational study of six months duration was carried out in 158 CKD patients on hemodialysis for a minimum period of one month. Data such as socio-demographic, clinical characteristics and dialysis practice details were captured from the patient’s medical records into the pre-designed Patient Proforma. The collected data were analysed. Results: Majority of respondents were male (67.09%), more than 60 y of age (32.28 %), married (89.24%). Hypertension (26.51%, 17.33%) was found to be the leading cause of CKD in a tertiary and private hospital. In the tertiary hospital, 78.31% of patients were undergoing twice-weekly hemodialysis, whereas in the private hospital thrice weekly (50.67%) hemodialysis was common. About 51.81% of patients in the tertiary and 58.67% in the private hospital was undergoing hemodialysis for 1-5 y with Arterio-Venous Fistula (59.04%, 94.67%) as the permanent vascular access (P<0.001). Conclusion: This study shows that hypertension was the leading cause of CKD in both hospitals. In the tertiary hospital twice weekly hemodialysis with arteriovenous fistula (AVF) and Permanent Catheter (IJV), were both preferred as the permanent vascular access. Whereas in the private hospital majority were undergoing thrice weekly hemodialysis and AVF was highly preferred

Positioning sensory terminals in the olfactory lobe of Drosophila by Robo signaling

Olfactory receptor neurons and the interneurons of the olfactory lobe are organized in distinct units called glomeruli. We have used expression patterns and genetic analysis to demonstrate that a combinatorial code of Roundabout (Robo) receptors act to position sensory terminals within the olfactory lobe. Groups of sensory neurons possess distinct blends of Robo and Robo3 and disruption of levels by loss-of-function or ectopic expression results in aberrant targeting. In the wild type, most of the neurons send collateral branches to the contralateral lobe. Our data suggests that guidance of axons across brain hemispheres is mediated by Slit-dependent Robo2 signaling. The location of sensory arbors at distinct positions within the lobe allows short-range interactions with projection neurons leading to formation of the glomeruli

Distinct types of glial cells populate the Drosophila antenna

Background The development of nervous systems involves reciprocal interactions between neurons and glia. In the Drosophila olfactory system, peripheral glial cells arise from sensory lineages specified by the basic helix-loop-helix transcription factor, Atonal. These glia wrap around the developing olfactory axons early during development and pattern the three distinct fascicles as they exit the antenna. In the moth Manduca sexta, an additional set of central glia migrate to the base of the antennal nerve where axons sort to their glomerular targets. In this work, we have investigated whether similar types of cells exist in the Drosophila antenna. Results We have used different P(Gal4) lines to drive Green Fluorescent Protein (GFP) in distinct populations of cells within the Drosophila antenna. Mz317::GFP, a marker for cell body and perineural glia, labels the majority of peripheral glia. An additional ~30 glial cells detected by GH146::GFP do not derive from any of the sensory lineages and appear to migrate into the antenna from the brain. Their appearance in the third antennal segment is regulated by normal function of the Epidermal Growth Factor receptor and small GTPases. We denote these distinct populations of cells as Mz317-glia and GH146-glia respectively. In the adult, processes of GH146-glial cells ensheath the olfactory receptor neurons directly, while those of the Mz317-glia form a peripheral layer. Ablation of GH146-glia does not result in any significant effects on the patterning of the olfactory receptor axons. Conclusion We have demonstrated the presence of at least two distinct populations of glial cells within the Drosophila antenna. GH146-glial cells originate in the brain and migrate to the antenna along the newly formed olfactory axons. The number of cells populating the third segment of the antenna is regulated by signaling through the Epidermal Growth Factor receptor. These glia share several features of the sorting zone cells described in Manduca

Norepinephrine directly activates adult hippocampal precursors via beta(3)-adrenergic receptors

Adult hippocampal neurogenesis is a critical form of cellular plasticity that is greatly influenced by neural activity. Among the neurotransmitters that are widely implicated in regulating this process are serotonin and norepinephrine, levels of which are modulated by stress, depression and clinical antidepressants. However, studies to date have failed to address a direct role for either neurotransmitter in regulating hippocampal precursor activity. Here we show that norepinephrine but not serotonin directly activates self-renewing and multipotent neural precursors, including stem cells, from the hippocampus of adult mice. Mechanistically, we provide evidence that beta(3)-adrenergic receptors, which are preferentially expressed on a Hes5-expressing precursor population in the subgranular zone (SGZ), mediate this norepinephrine-dependent activation. Moreover, intrahippocampal injection of a selective beta(3)-adrenergic receptor agonist in vivo increases the number of proliferating cells in the SGZ. Similarly, systemic injection of the beta-adrenergic receptor agonist isoproterenol not only results in enhancement of proliferation in the SGZ but also leads to an increase in the percentage of nestin/glial fibrillary acidic protein double-positive neural precursors in vivo. Finally, using a novel ex vivo "slice-sphere" assay that maintains an intact neurogenic niche, we demonstrate that antidepressants that selectively block the reuptake of norepinephrine, but not serotonin, robustly increase hippocampal precursor activity via beta-adrenergic receptors. These findings suggest that the activation of neurogenic precursors and stem cells via beta(3)-adrenergic receptors could be a potent mechanism to increase neuronal production, providing a putative target for the development of novel antidepressants

α2-adrenoceptor blockade accelerates the neurogenic, neurotrophic, and behavioral effects of chronic antidepressant treatment

Slow-onset adaptive changes that arise from sustained antidepressant treatment, such as enhanced adult hippocampal neurogenesis and increased trophic factor expression, play a key role in the behavioral effects of antidepressants. alpha(2)-Adrenoceptors contribute to the modulation of mood and are potential targets for the development of faster acting antidepressants. We investigated the influence of alpha(2)-adrenoceptors on adult hippocampal neurogenesis. Our results indicate that alpha(2)-adrenoceptor agonists, clonidine and guanabenz, decrease adult hippocampal neurogenesis through a selective effect on the proliferation, but not the survival or differentiation, of progenitors. These effects persist in dopamine beta-hydroxylase knock-out (Dbh(-/-)) mice lacking norepinephrine, supporting a role for alpha(2)-heteroceptors on progenitor cells, rather than alpha(2)-autoreceptors on noradrenergic neurons that inhibit norepinephrine release. Adult hippocampal progenitors in vitro express all the alpha(2)-adrenoceptor subtypes, and decreased neurosphere frequency and BrdU incorporation indicate direct effects of alpha(2)-adrenoceptor stimulation on progenitors. Furthermore, coadministration of the alpha(2)-adrenoceptor antagonist yohimbine with the antidepressant imipramine significantly accelerates effects on hippocampal progenitor proliferation, the morphological maturation of newborn neurons, and the increase in expression of brain derived neurotrophic factor and vascular endothelial growth factor implicated in the neurogenic and behavioral effects of antidepressants. Finally, short-duration (7 d) yohimbine and imipramine treatment results in robust behavioral responses in the novelty suppressed feeding test, which normally requires 3 weeks of treatment with classical antidepressants. Our results demonstrate that alpha(2)-adrenoceptors, expressed by progenitor cells, decrease adult hippocampal neurogenesis, while their blockade speeds up antidepressant action, highlighting their importance as targets for faster acting antidepressants

A morphology independent approach for identifying dividing adult neural stem cells in the mouse hippocampus

Background: Type 1 adult hippocampal neural stem cells (AH-NSCs) continue to generate neurons throughout life, albeit at a very low rate. The relative quiescence of this population of cells has led to many studies investigating factors that may increase their division. Current methods of identifying dividing AH-NSCs in vivo require the identification and tracing of radial processes back to nuclei within the subgranular zone. However, caveats to this approach include the time-intensive nature of identifying AH-NSCs with such a process, as well as the fact that this approach ignores the relatively more active population of horizontally oriented AH-NSCs that also reside in the subgranular zone. Results: Here we describe, and then verify using Hes5::GFP mice, that labeling for the cell cycle marker Ki67 and selection against the intermediate progenitor cell marker TBR2 (Ki67; TBR2 nuclei) is sufficient to identify dividing horizontally and radially oriented AH-NSCs in the adult mouse hippocampus. Conclusions: These findings provide a simple and accurate way to quantify dividing AH-NSCs in vivo using a morphology-independent approach that will facilitate studies into neurogenesis within the hippocampal stem cell niche of the adult brain. Developmental Dynamics 247:194–200, 2018

Purification of neural precursor cells reveals the presence of distinct, stimulus-specific subpopulations of quiescent precursors in the adult mouse hippocampus

The activity of neural precursor cells in the adult hippocampus is regulated by various stimuli; however, whether these stimuli regulate the same or different precursor populations remains unknown. Here, we developed a novel cell-sorting protocol that allows the purification to homogeneity of neurosphere-forming neural precursors from the adult mouse hippocampus and examined the responsiveness of individual precursors to various stimuli using a clonal assay. We show that within the Hes5-GFP(+) /Nestin-GFP(+) /EGFR(+) cell population, which comprises the majority of neurosphere-forming precursors, there are two distinct subpopulations of quiescent precursor cells, one directly activated by high-KCl depolarization, and the other activated by norepinephrine (NE). We then demonstrate that these two populations are differentially distributed along the septotemporal axis of the hippocampus, and show that the NE-responsive precursors are selectively regulated by GABA, whereas the KCl-responsive precursors are selectively modulated by corticosterone. Finally, based on RNAseq analysis by deep sequencing, we show that the progeny generated by activating NE-responsive versus KCl-responsive quiescent precursors are molecularly different. These results demonstrate that the adult hippocampus contains phenotypically similar but stimulus-specific populations of quiescent precursors, which may give rise to neural progeny with different functional capacity