205 research outputs found
Hypothalamic neurons secreting vasopressin and neurophysin
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
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
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
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
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
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
Recommended from our members
Protocols for Monitoring Habitat Restoration Projects in the Lower Columbia River and Estuary
Protocols for monitoring salmon habitat restoration projects are essential for the U.S. Army Corps of Engineers' environmental efforts in the Columbia River estuary. This manual provides state-of-the science data collection and analysis methods for landscape features, water quality, and fish species composition, among others
HIV-1 Entry, Inhibitors, and Resistance
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
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)
Recommended from our members
Effect of nanoscale patterned interfacial roughness on interfacial toughness.
The performance and the reliability of many devices are controlled by interfaces between thin films. In this study we investigated the use of patterned, nanoscale interfacial roughness as a way to increase the apparent interfacial toughness of brittle, thin-film material systems. The experimental portion of the study measured the interfacial toughness of a number of interfaces with nanoscale roughness. This included a silicon interface with a rectangular-toothed pattern of 60-nm wide by 90-nm deep channels fabricated using nanoimprint lithography techniques. Detailed finite element simulations were used to investigate the nature of interfacial crack growth when the interface is patterned. These simulations examined how geometric and material parameter choices affect the apparent toughness. Atomistic simulations were also performed with the aim of identifying possible modifications to the interfacial separation models currently used in nanoscale, finite element fracture analyses. The fundamental nature of atomistic traction separation for mixed mode loadings was investigated
- …