Pax6 is required intrinsically by thalamic progenitors for the normal molecular patterning of thalamic neurons but not the growth and guidance of their axons

BACKGROUND: In mouse embryos, the Pax6 transcription factor is expressed in the progenitors of thalamic neurons but not in thalamic neurons themselves. Its null-mutation causes early mis-patterning of thalamic progenitors. It is known that thalamic neurons generated by Pax6(−/−) progenitors do not develop their normal connections with the cortex, but it is not clear why. We investigated the extent to which defects intrinsic to the thalamus are responsible. RESULTS: We first confirmed that, in constitutive Pax6(−/−) mutants, the axons of thalamic neurons fail to enter the telencephalon and, instead, many of them take an abnormal path to the hypothalamus, whose expression of Slits would normally repel them. We found that thalamic neurons show reduced expression of the Slit receptor Robo2 in Pax6(−/−) mutants, which might enhance the ability of their axons to enter the hypothalamus. Remarkably, however, in chimeras comprising a mixture of Pax6(−/−) and Pax6(+/+) cells, Pax6(−/−) thalamic neurons are able to generate axons that exit the diencephalon, take normal trajectories through the telencephalon and avoid the hypothalamus. This occurs despite abnormalities in their molecular patterning (they express Nkx2.2, unlike normal thalamic neurons) and their reduced expression of Robo2. In conditional mutants, acute deletion of Pax6 from the forebrain at the time when thalamic axons are starting to grow does not prevent the development of the thalamocortical tract, suggesting that earlier extra-thalamic patterning and /or morphological defects are the main cause of thalamocortical tract failure in Pax6(−/−) constitutive mutants. CONCLUSIONS: Our results indicate that Pax6 is required by thalamic progenitors for the normal molecular patterning of the thalamic neurons that they generate but thalamic neurons do not need normal Pax6-dependent patterning to become competent to grow axons that can be guided appropriately

The effects of Alloglossidium corti (Trematoda: macroderoididae) on its molluscan intermediate host Helisoma trivolvis (Gastropoda: planorbidae) in the Little Brazos River, Texas

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Bibliography: leaves 54-58.Not availabl

A meta-collection of nitrogen stable isotope data measured in Arctic marine organisms from the Canadian Beaufort Sea, 1983–2013

Objectives Existing information on Arctic marine food web structure is fragmented. Integrating data across research programs is an important strategy for building a baseline understanding of food web structure and function in many Arctic regions. Naturally-occurring stable isotope ratios of nitrogen (δ15N) and carbon (δ13C) measured directly in the tissues of organisms are a commonly-employed method for estimating food web structure. The objective of the current dataset was to synthesize disparate δ15N, and secondarily δ13C, data in the Canadian Beaufort continental shelf region relevant to trophic and ecological studies at the local and pan-Arctic scales. Data description The dataset presented here contains nitrogen and carbon stable isotope ratios (δ15N, δ13C) measured in marine organisms from the Canadian Beaufort continental shelf region between 1983 and 2013, gathered from 27 published and unpublished sources with associated sampling metadata. A total of 1077 entries were collected, summarizing 8859 individual organisms/samples representing 333 taxa across the Arctic food web, from top marine mammal predators to primary producers

Effect of lower blood pressure goals on left ventricular structure and function in patients with subclinical hypertensive heart disease

© American Journal of Hypertension, Ltd 2020. All rights reserved. For Permissions, please email: [email protected] BACKGROUND Subclinical hypertensive heart disease (SHHD) is a precursor to heart failure. Blood pressure (BP) reduction is an important component of secondary disease prevention in patients with SHHD. Treating patients with SHHD utilizing a more intensive BP target (120/80 mm Hg), may lead to improved cardiac function but there has been limited study of this, particularly in African Americans (AAs). METHODS We conducted a single center, randomized controlled trial where subjects with uncontrolled, asymptomatic hypertension, and SHHD not managed by a primary care physician were randomized to standard (\u3c140/90 mm Hg) or intensive (\u3c120/80 mm Hg) BP therapy groups with quarterly follow-up for 12 months. The primary outcome was the differences of BP reduction between these 2 groups and the secondary outcome was the improvement in echocardiographic measures at 12 months. RESULTS Patients (95% AAs, 65% male, mean age 49.4) were randomized to the standard (n = 65) or the intensive (n = 58) BP therapy groups. Despite significant reductions in systolic BP (sBP) from baseline (−10.9 vs. −19.1 mm Hg, respectively) (P \u3c 0.05), no significant differences were noted between intention-to-treat groups (P = 0.33) or the proportion with resolution of SHHD (P = 0.31). However, on post hoc analysis, achievement of a sBP \u3c130 mm Hg was associated with significant reduction in indexed left ventricular mass (−6.91 gm/m2.7; P = 0.008) which remained significant on mixed effect modeling (P = 0.031). CONCLUSIONS In post hoc analysis, sBP \u3c130 mm Hg in predominantly AA patients with SHHD was associated with improved cardiac function and reverse remodeling and may help to explain preventative effects of lower BP goals