The increase in prolactin-secreting cells in incubating chicken hens can be mimicked by extended treatment of pituitary cells in vitro with vasoactive intestinal polypeptide (VIP)

Incubation of eggs by birds and lactation in mammals are regulated by pituitary prolactin (PRL) and associated with an increase in pituitary PRL-producing cells or lactotrophs. However, the mechanisms controlling this increase in lactotroph numbers are not known. PRL secretion in birds is regulated by vasoactive intestinal polypeptide (VIP). This study was designed to determine whether VIP treatment could modulate lactotroph abundance in culture. Anterior pituitary cells were isolated from laying Japanese White Silkie hens and cultured for 2 or 6 days in the absence or presence of VIP. PRL-secreting cells were identified by reverse hemolytic plaque assay. Treatment with VIP for 6 days substantially increased the abundance of PRL-secreting cells from 47.5% under basal conditions to 70.6% of all pituitary cells following VIP stimulation. However, 2-day VIP treatment had no effect. Furthermore, the extent to which the hens were allowed to accumulate eggs in a clutch prior to isolation of the pituitaries did not affect the lactotroph response to VIP in vitro. These findings indicate that chronic VIP stimulation may be responsible for the increased abundance of lactotrophs found in the pituitary glands of incubating hens.     

Pharmacodynamics of carvedilol in conscious, healthy dogs

The purpose of the study reported here was to determine the magnitude and duration of beta-blocking efficacy, determine an effective dose and dosing interval, and document safety and tolerability of carvedilol given orally in clinically normal dogs. Pharmacodynamic data were evaluated in conscious, unrestrained, healthy hound dogs at baseline and after long-term oral administration of carvedilol (1.5 mg/kg of body weight PO q12h for >5 days). At baseline, heart rate (HR) and blood pressure (BP) data were collected continuously for 24 hours, and complete echocardiography was performed. This protocol was repeated after long-term oral carvedilol administration. Additionally, isoproterenol was administered to evaluate the magnitude and duration of the nonselective beta-blocking efficacy of carvedilol. An isoproterenol challenge was performed 0.75, 1.5, 2.25, 4, 6, 12, and 24 hours after carvedilol administration, with echocardiography being performed once at 2 hours. Plasma samples were obtained prior to each challenge time point for determination of plasma carvedilol concentration. Time series regression analysis indicated no difference between baseline and carvedilol-induced HR or BP trend lines in 6 of 8 dogs. In 2 of 8 dogs, HR, after long-term carvedilol administration, was reduced. Carvedilol attenuated isoproterenol-induced changes in HR by 54-76% through 12 hours and by 30% at 24 hours. The BP changes were attenuated by 80-100% through 12 hours. These data suggest that carvedilol (1.5 mg/kg PO q12h) in healthy, conscious dogs confers nonselective beta blockade for 12 hours, with minimal effects on resting HR, BP, and echocardiographic variables. Additionally, the magnitude of beta blockade correlated strongly to peak plasma carvedilol concentration, suggesting that therapeutic drug monitoring may be clinically useful.     

The health of wild red and sika deer in Scotland: an analysis of key endoparasites and recommendations for monitoring disease

Monitoring the health of wildlife populations is important for understanding and controlling the risk of infections to livestock, humans and/or other wildlife. In this paper, we analyse the results of surveys of parasites and non-specific signs of diseases carried out on organs from 638 red and 107 sika deer culled in four regions of Scotland between 1991 and 1997. Infections of the lung by Elaphostrongylus spp. were significantly greater in red than sika deer. Older animals were more heavily infected with Elaphostrongylus spp. and Sarcocystis spp., and infections with Sarcocystis spp. tended to be heavier in more recent years. The results suggest that a combination of key indicator parasite species and non-specific signs of disease may be useful for monitoring the health of wildlife populations at a national scale. However, they also demonstrate that such monitoring needs to be long-term, carried out according to standard protocols and at an appropriate resolution to enable integration with data on other potentially influential environmental factors.     

Anaerobic biotransformation of organo-arsenical pesticides monomethylarsonic acid and dimethylarsinic acid

Monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) are extensively utilized as pesticides, introducing large quantities of arsenic into the environment. Once released into the environment, these organo-arsenicals are subject to microbial reactions. Aerobic biodegradation of MMAV and DMAV has been evaluated, but little is known about their fate in anaerobic environments. The objective of this study was to evaluate the biotransformation of MMAV and DMAV in anaerobic sludge. Biologically mediated conversion occurred under methanogenic or sulfate-reducing conditions but not in the presence of nitrate. Monomethylarsonous acid (MMAIII) was consistently observed as an important metabolite of MMAV degradation, and it was recovered in molar yields ranging from 5 to 47%. The main biotransformation product identified from DMAV metabolism was MMAV, which was recovered in molar yields ranging from 8 to 65%. The metabolites indicate that reduction and demethylation are important steps in the anaerobic bioconversion of MMAV and DMAV, respectively.     

Mineralogy and petrology of comet 81P/Wild 2 nucleus samples

The bulk of the comet 81P/Wild 2 (hereafter Wild 2) samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger (over 1 micrometer) ferromagnesian silicates, Fe-Ni sulfides, Fe-Ni metal, and accessory phases. The very wide range of olivine and low-Ca pyroxene compositions in comet Wild 2 requires a wide range of formation conditions, probably reflecting very different formation locations in the protoplanetary disk. The restricted compositional ranges of Fe-Ni sulfides, the wide range for silicates, and the absence of hydrous phases indicate that comet Wild 2 experienced little or no aqueous alteration. Less abundant Wild 2 materials include a refractory particle, whose presence appears to require radial transport in the early protoplanetary disk.     

Land Application of Lake-Dredged Materials for Bahiagrass Establishment in the Subtropical Beef Pasture

Background  The continued need to dredge lakes, rivers, and canals in Florida, both for maintenance and environmental improvement, will produce millions of cubic meters of dredged materials. Productive disposal options of lake-dredged materials (LDM) may provide substantial and intangible benefits that will enhance the environment, community, and society. Objective  The objective of this study was to assess lake-dredged materials from Lake Panasoffkee as soil amendment for early establishment of bahiagrass (BG,Paspalum notatum Flügge) in subtropical beef cattle pasture at Sumter County, Florida. Results and Discussion. This study encompassed two phases: Phase 1 comprised of five small observation plots (0.3 x 0.3 m); Phase 2 consisted of five larger test plots (30.5 x 30.5 m). Each of the plots in Phase 1 and Phase 2 had a different ratio LDM to natural soil (NS): Plot 1 (0% LDM + 100% NS); Plot 2 (25% LDM + 75% NS); Plot 3 (50% LDM + 50% NS); Plot 4 (75% LDM + 25% NS); and Plot 5 (100% LDM + 0% NS). Each plot was seeded with BG and early growth and yield establishment were monitored for 16 weeks. Conclusion  Results disclosed significantly taller (p ≤ 0.001) plants and higher biomass production (p ≤ 0.001) of BG from plots amended with 75% LDM than those of BG planted on plots with 0% LDM. Results suggest that LDM can serve as source of lime and fertilizer to establish BG beef pasture fields. Sediments with high CaCO₃ improved the physical and chemical conditions of subtropical beef pastures. Lake-dredged materials could be removed from the spoil containment areas, trucked to other locations, and incorporated into existing fields for agricultural uses. There is still much to be learned, but it is certain that Lake Panasoffkee sediments should be regarded as a resource, with no observed harmful ecological effects. Recommendation and Outlook  The agricultural or livestock industry could utilize these LDM to produce forages. LDM should be regarded as a beneficial resource, as a part of the ecological system. This study has been continued for several years to explore and assess the long term efficacy of LDM on productivity and quality of BG beyond its early establishment stage. Joint contribution of the USDA-ARS and the Florida Agricultural Experiment Station, Journal Series No, R-09253.