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“Chronic postnatal hyperoxia blunts the hypoxic ventilatory response (HVR) in rats, an effect that persists for months after return to normoxia. To determine whether decreased carotid body O-2 sensitivity contributes to this lasting impairment, single-unit chemoafferent nerve and glomus cell calcium responses to hypoxia were recorded from rats reared in 60% O-2 through 7d of age (P7) and then returned to normoxia. Single-unit nerve responses were attenuated by P4 and remained low through P7. After return to normoxia, hypoxic responses were partially recovered within 3d and fully
recovered within 7-8 d (i.e., at P14-15). Glomus cell calcium responses recovered with a similar time course. Hyperoxia altered carotid body mRNA expression for O-2-sensitive K+ channels TASK-1, TASK-3, and BKCa, but only TASK-1 mRNA paralleled HM781-36B changes in chemosensitivity (i.e., downregulation by P7, partial recovery by P14). Collectively, these data do not support a role for reduced O-2 sensitivity of individual chemoreceptor cells in long-lasting reduction of the HVR after developmental hyperoxia. (C) 2011
Elsevier B.V. All rights reserved.”
“BACKGROUND\n\nRuminants produce large quantities of methane in their rumen as a by-product of microbial digestion of feed. Antibiotics are added to ruminant feed to reduce wasteful production of methane; however, this practice has some downsides. A search for safer and natural feed additives with anti-methanogenic properties is under way. The objective of this research was to examine selected feed additives, plant essential oils and plant extracts for their anti-methanogenic Selleckchem TH-302 GSK3235025 potential in the rumen using an in vitro batch fermentation system.\n\nRESULTS\n\nA significant reduction (P < 0.05) in methane production was observed with nine feed additives (up to 40% reduction), all eight essential oils (up to 75% reduction) and two plant extracts (14% reduction) when compared to their respective controls. Amongst these, only an algal meal high
in docosahexaenoic acid, preparations of Nannochloropsis oculata, calcareous marine algae, yeast metabolites and two tannins did not inhibit microbial gas and volatile acid production.\n\nCONCLUSIONS\n\nThe current study identified some potent dietary ingredients or plant compounds that can assist in developing novel feed additives for methane mitigation from the rumen. (c) 2013 Society of Chemical Industry”
“The Harvard School of Dental Medicine (HSDM) uses a hybrid problem-based learning (PBL) approach to teaching in the D.M.D. curriculum. Each tutorial group at HSDM is made up of eight to ten students. The objective of this study was to examine the performance of the students in the tutorial sessions as assessed by the tutor. A total of ten tutorial blocks led by twenty-four tutorial leaders were completed at HSDM between summer 2008 and fall 2009.