205 research outputs found

    Hypothalamic neurons secreting vasopressin and neurophysin

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    Vasopressin is synthesized in the magnocellular system of the hypothalamus in clusters of cells which form the supraoptic nucleus and the paraventricular nucleus. The hormone is synthesized and packaged in neurosecretory granules with an intragpanular protein, neurophysin. The demonstration of axon flow of neurosecretory granules from the perikarya in the hypothalamus to the posterior lobe of the pituitary and subsequent release into the blood has been an important historical chapter in our understanding of neurosecretion. Isolation of neurophysins from several species and development of antisera to these peptides as well as antibodies to vasopressin have provided new tools to re-examine this system. In several species, the data indicate a specific neurophysin for vasopressin and a different neurophysin for oxytocin. It is now well established that neurophysins are secreted with hormones and this has provided a cogent argument that exocytosis is a major form of neurosecretion of vasopressin. Assay of neurophysin in plasma can be used to study vasopressin release. Immunohistochemical studies using antibodies to vasopressin and neurophysin demonstrated that the magnocellular system is more diffusely distributed throughout the hypothalamus than was previously appreciated. In addition, vasopressin and neurophysin are formed in both the supraoptic and paraventricular neurons and there are three pathways of secretion. The major pathway is the supraoptico-hypophyseal tract to the posterior lobe. The second pathway is to the external zone of the median eminence for secretion into the hypophyseal portal blood. The third pathway is to the third ventricle for secretion into cerebral spinal fluid. Vasopressin in the external zone is greatly increased by the absence of adrenal cortical steroids which suggests that vasopressin may play a role in the hypothalamic anterior pituitary adrenal axis. The cerebral spinal fluid pathway may be important in man if vasopressin is found to have the memory consolidating effects which have been investigated in other animals

    The Incidence of Parasitism in Iowa Cattle

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    The importance of cattle parasitism is gaining recognition throughout the world with more emphasis being placed on the incidence, significance and effective control of parasites. The mortality of cattle due to parasitism is relatively low but the morbidity is high due to such losses as inefficient feed utilization and retarded growth and development. Cattle parasitism has been of economic importance for some time in southern United States and in the parts of western United States were irrigation is employed. Increasing interstate movement of cattle has enlarged the area where parasitism is a problem. A fecal study of Iowa cattle was initiated in 1955 in order to determine the extent of bovine parasitism in this state

    Distribution of Baird\u27s Pocket Gopher (Geomys breviceps) In Arkansas; with Additional County Records

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    Recently, a population of pocket gophers in the north-central portion of Arkansas was determined to be the plains pocket gopher (Geomys Imrsarius), rather than Baird\u27s pocket gopher (Geomys breviceps). This changed the known range of both species extensively. A detailed examination of the known range of Baird\u27s pocket gophers (G. breviceps) in Arkansas resulted in 12 new county records. Biogeographically, G. breviceps appears to be found in all physiographic regions within the state with the possible exception ofCrowley\u27s ridge. It is most common in the Gulf Coastal Plain and rarest in the Mississippi Alluvial Plain. The distribution ofG. breviceps is consistent with the hypothesis that glaciation events, together withnorthward invasions from Louisiana and eastern Texas and eastward invasions from Oklahoma (around the Ouachita Mountains) were major creational forces in the establishment of the present G. breviceps distribution in Arkansas

    Texture of Butters Made from Milks Differing in Indices of Atherogenicity

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    The current study examined whether the phenotypic variation in milk fatty acid composition among cows fed the same diet was sufficient to produce butter with different textural properties. Butter samples from cows with a more unsaturated milk fatty acid composition had a lower index of atherogenicity and were more spreadable, softer, and less adhesive than were butter samples from cows with a more saturated milk fatty acid composition. Thus, selection of cows for milk fatty acid composition short-term by segregation and long-term by breeding programs can be used to produce butter that is more healthful and has a more favorable texture

    Butter Composition and Texture from Cows with Different Milk Fatty Acid Compositions Fed Fish Oil or Roasted Soybeans

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    Nutritional and physical properties of dairy products can be improved by changing milk fatty acid composition toward more unsaturation. Diet of cows, e.g., feeding supplemental fish oil (FO) or roasted soybeans (RSB), and cow selection can improve the nutritional and physical properties of dairy products and their acceptability to consumers. We examined whether feeding supplemental FO or RSB to cows that had a more unsaturated milk fatty acid composition acted additively to produce butter with improved fatty acid composition and texture. Multiparous Holstein cows chosen for producing either more or less unsaturated milk fatty acid composition (n = 6 in each group) were fed for three 3-week periods a control diet and two experimental diets that included additionally 0.9% of FO or 5% of RSB. The milk, collected in the third week of feeding, was used to make butter, which was analyzed for its fatty acid composition and physical properties. Dry matter intake, milk yield, and milk composition were not significantly affected by cow diet or by cow selection. Cows that produced, prior to the feeding study, a more unsaturated and healthful milk fat using a “health-promoting index” (HPI = [sum of % of unsaturated fatty acids] / [%C12:0 + 4 x %C14:0 + %C16:0]) maintained during the feeding study a higher HPI in their butter than did cows with a low HPI. Milk from cows fed supplemental FO or RSB yielded more unsaturated butters with higher HPI. This butter also was softer when the cows were fed RSB. Feeding RSB to cows chosen for their high milk HPI yielded the most unsaturated butter with the highest HPI and softest texture. Thus, selecting cows with a more healthful milk fatty acid composition and feeding cows supplemental RSB additively improved butter fatty acid composition and texture

    Immunocytochemistry of the C-terminal peptide of propressophysin (CPP): Relationship to vasopressin, oxytocin and neurophysin

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    Arginine-vasopressin (AVP) and its associated neurophysin (AVP-NP) are synthesized via a precursor, propressophysin, which also contains a 39 amino acid glycopeptide at its C-terminus (C-terminus of propressophysin, or CPP). In the present study, immunocytochemical techniques were used to determine the cellular co-localization of CPP with AVP, oxytocin (OXY), AVP-NP and OXY-NP in the rat hypothalamus using colchicine pre-treatment and serial 5 [mu]m section analysis. Extensive cross-competition studies of antisera raised against each peptide with the various antigens yielded no significant crossreactivity of the CPP, AVP, OXY and NP antisera. The NP antiserum, although directed against both AVP-NP and OXY-NP, demonstrated a preference for OXY-NP at a dilution of 1:20,000. CPP and AVP were always co-localized within the same magnocellular neurons of the supraoptic, paraventricular and circularis nuclei, and further showed very similar patterning in the suprachiasmatic nucleus as well. In conrast, no cellular overlap could be detected between CPP and OXY, in any of the above nuclei (the suprachiasmatic nucleus is devoid of OXY). Likewise, no examples of co-localization of CPP and OXY-NP were found in the magnocellular nuclei. These results are in strong agreement with a biosynthetic relationship between CPP, AVP and AVP-NP, and their separateness from the OXY and OXY-NP precursor.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25176/1/0000615.pd

    HIV-1 Entry, Inhibitors, and Resistance

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    Entry inhibitors represent a new class of antiretroviral agents for the treatment of infection with HIV-1. While resistance to other HIV drug classes has been well described, resistance to this new class is still ill defined despite considerable clinical use. Several potential mechanisms have been proposed: tropism switching (utilization of CXCR4 instead of CCR5 for entry), increased affinity for the coreceptor, increased rate of virus entry into host cells, and utilization of inhibitor-bound receptor for entry. In this review we will address the development of attachment, fusion, and coreceptor entry inhibitors and explore recent studies describing potential mechanisms of resistance

    Evaluating Cumulative Ecosystem Response to Restoration Projects in the Lower Columbia River and Estuary, 2009

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    This is the sixth annual report of a seven-year project (2004 through 2010) to evaluate the cumulative effects of habitat restoration actions in the lower Columbia River and estuary (LCRE). The project, called the Cumulative Effects Study, is being conducted for the U.S. Army Corps of Engineers Portland District (USACE) by the Marine Sciences Laboratory of the Pacific Northwest National Laboratory (PNNL), the Pt. Adams Biological Field Station of the National Marine Fisheries Service (NMFS), the Columbia River Estuary Study Taskforce (CREST), and the University of Washington. The goal of the Cumulative Effects Study is to develop a methodology to evaluate the cumulative effects of multiple habitat restoration projects intended to benefit ecosystems supporting juvenile salmonids in the 235-km-long LCRE. Literature review in 2004 revealed no existing methods for such an evaluation and suggested that cumulative effects could be additive or synergistic. From 2005 through 2009, annual field research involved intensive, comparative studies paired by habitat type (tidal swamp versus marsh), trajectory (restoration versus reference site), and restoration action (tidegate replacement vs. culvert replacement vs. dike breach)
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