Development of renal function tests for measurement of urine concentrating ability, urine acidification, and glomerular filtration rate in female cynomolgus monkeys.

This study was conducted to develop tests for evaluation of uri ne concentratingability, urine acidification ability, an dglomerular filtration rate in cynomolgus macaques. In female cynomolgus macaques, baseline urine specific gravity ranged from 1.005 to 1.

Gastroesophageal Intussusception Associated with Pneumonectomy in a Dog.

Gastroesophageal intussusception is a rare condition in dogs. We report a gastroesophageal intussusception in an adult dog which had been subjected to unilateral pneumonectomy as a pup. One year after the surgery, computerized tomography scans indicated megaesophagus in the caudal third of the thorax.

Pharmacologic studies on the mechanism of melatonin-induced vasorelaxation in rat aorta.

The influence of several classes of drugs on the melatonin-induced vasorelaxation of isolated rat aorta were examined. Melatonin caused a dose-dependent relaxation of precontracted (30 mM KCl) aorta. This relaxant response was blocked by preincubating vessels with antagonists of vasoactive intestinal peptide.

Tissue and plasma peptidase activity is altered during hypothermic hibernation in the 13 lined ground squirrel (Spermophilus tridecemlineatus).

Adult 13 lined ground squirrels were monitored for entry into a state of hypothermic hibernation or arousal in a cold room on a photoperiod LD 2:22. Once animals developed predictable hibernation patterns, animals were killed at the mid point of hypothermic hibernation or arousal for determination of plasma and tissue angiotensin-1-converting enzyme (Kininase II) activity. Enzyme was extracted from plasma, lung, kidney, liver, forebrain and brainstem and assayed in vitro.

Influence of melatonin on bovine pulmonary vascular and bronchial airway smooth muscle tone.

The influence of melatonin on tension of isolated bovine pulmonary vascular and bronchial smooth muscle rings were examined in these experiments. Melatonin caused a dose-dependent relaxation of precontracted (30 mM KCl) pulmonary artery and vein, although the effect is greater in arterial smooth muscle. This relaxant response was blocked by preincubating vessels with antagonists of vasoactive intestinal peptide or Substance P.

Effects of trichothecene mycotoxins on the ex vivo vascular smooth muscle responses to beta-adrenergic agonists.

The ex vivo biophysical response of isolated rat aorta to T-2 toxin, diacetoxyscirpenol (DAS) and Roridin-A were determined. Roridin-A caused a dose-dependent relaxation of precontracted (30 mM KCl) aorta, while T-2 toxin and DAS were without effect. On the other hand, the relaxation response of aorta to isoproterenol and sodium fluoride is impaired in the presence of T-2 toxin or DAS.

Altered endothelium-dependent alpha-adrenergic vascular reactivity following exposure to Pasteurella haemolytica antigens.

Rats were injected with sterile saline (controls), 10(5) cfu of Pasteurella haemolytica (biotype A) obtained from a commercial vaccine, or a commercial Pasteurella leukotoxoid vaccine. Three days after vaccination, the animals were killed and the thoracic aorta was removed. In some experiments the vascular endothelium was mechanically removed.

Disturbances in ex vivo vascular smooth muscle responses following exposure to Pasteurella haemolytica vaccines.

Rats were vaccinated with saline (control) or one of the two commercially available Pasteurella haemolytica vaccines Presponse or Precon-PH. Animals were killed 3 days later and thoracic aorta removed for evaluation of the ex vivo biophysical responses to carbachol (CCh). In some experiments, vascular endothelium was mechanically removed.

Vaccine-derived Pasteurella haemolytica alter the responses of ovine pulmonary artery and vein to drugs acting on adenylate cyclase.

Sheep were vaccinated with a live, vaccine-derived strain of Pasteurella haemolytica. The ex vivo response of isolated pulmonary artery and vein to isoproterenol, cholera toxin, sodium fluoride and calcium were examined three days after vaccination. In the pulmonary artery (endothelium intact), vaccination did not alter the response to isoproterenol, or sodium fluoride whereas the relaxation response to cholera toxin was impaired.

Effects of melatonin on isolated pulmonary artery and vein: role of the vascular endothelium.

The influence of melatonin on tension of isolated pulmonary vascular smooth muscle rings was examined in these experiments. Melatonin caused a dose-dependent relaxation of precontracted (30 mM KCl) pulmonary artery and pulmonary vein. Removal of the endothelium did not alter the relaxant response to melatonin in pulmonary artery.

Vaccination with live Pasteurella haemolytica alters vascular adrenergic reactivity.

Rats were injected with sterile saline (controls) or 0.7 x 10(5) c.f.

Effects of melatonin on pulmonary and coronary vessels are exerted through perivascular nerves.

The effects of melatonin on porcine pulmonary and coronary vessels have been studied. Vessels were isolated from normal pigs, placed in a tissue bath, and precontracted with 30 mM KCl. The biophysical responses to cumulative doses of melatonin were then assessed.

Morphological and functional disturbances in pulmonary vascular endothelium following exposure of sheep to an "avirulent" strain of Pasteurella haemolytica.

Sheep were vaccinated with a live attenuated strain of Pasteurella haemolytica and killed 3 days later. Segments of main intrapulmonic artery and vein were removed for biophysical and scanning electron microscopic studies. In the pulmonary artery, vaccination with Pasteurella haemolytica caused an increase in the number of endothelial cell surface blebs and, in some cases, those blebs appeared to be splitting open, suggesting cell damage or irritation.

The effect of aflatoxin B1 exposure on serotonin metabolism: response to a tryptophan load.

Semi-chronic exposure of ICR male Mice to Aflatoxin B1 (AFB1) in non-toxic doses decreased brain serotonin (5-hydroxytryptamine, 5-HT), 5-hydroxyindole-3-acetic acid (5-HIAA) and catecholamines without altering tryptophan (TRP) or tyrosine (TYR) levels. A TRP load (300 mg/kg, i.p.

Renal renin secretion rate and norepinephrine secretion rate in response to centrally administered angiotensin-II: role of the medial basal forebrain.

The influence that centrally administered angiotensin-II (ANG-II) and saralasin (SAR) has on renal norepinephrine secretion rate (NESR) and renal renin secretion rate (RSR) were studied. Rats were given thermal lesions of the medial basal forebrain (MBF) or sham surgery. Twenty-four hours later the right kidney was vascularly isolated (but neurally intact) and perfused with an artificial plasma at either a constant pressure (100 mm Hg) or constant flow (600 microliters/min).

Exposure of sheep to Pasteurella haemolytica alters ex vivo pulmonary vascular smooth muscle alpha adrenergic responses: role of vascular endothelium.

Sheep were exposed to a live- vaccine derived strain of Pasteurella haemolytica (10(5) colony forming units/sheep, i.m.) and euthanized 3 days later.

Melatonin-induced relaxation of rat aorta: interaction with adrenergic agonists.

The influence of melatonin on alpha- and beta-adrenergic responses of vascular smooth muscle ex vivo were examined in these experiments. Melatonin caused a dose-dependent relaxation of precontracted (30 mM KCl) vascular smooth muscle. This response was not affected by the removal of vascular endothelium.

Angiotensin-II acts centrally to alter renal sympathetic nerve activity and the intrarenal renin-angiotensin system.

Study Objective: The aim was to evaluate the influence that centrally administered angiotensin-II has on the intrarenal renin-angiotensin system and renal sympathetic nerve activity.

Design: Renal responses to centrally administered angiotensin-II (10 micrograms) or saralasin (50 micrograms) were measured in anaesthetised rats. The right kidney was vascularly isolated (but neurally intact) and perfused with artificial plasma at either a constant pressure (13.

Aflatoxin B1 alters central and systemic tryptophan and tyrosine metabolism: influence of immunomodulatory drugs.

Semi-chronic exposure of ICR male Mice to Aflatoxin B1 (AFB1) in non-toxic doses results in elevated lung tryptophan (TRP) levels without change in serotonin (5-HT) or 5-hydroxyindole-3-acetic acid (5-HIAA) levels. This change is organ specific in that TRP levels are not altered in spleen, duodenum, heart or central nervous system (CNS). Acute (48 hour) flunixin treatment decreases lung TRP levels and reverses the AFB1 mediated increase in lung TRP levels.

Rat duodenal smooth muscle contractile responses to angiotensin II are dependent on calmodulin.

1. Isolated duodenal segments were pretreated with either of the calmodulin inhibitors proadifen or trifluoroperazine and the subsequent contractile force and frequency response to angiotensin II monitored. 2.

Acute and chronic effects of the trichothecene mycotoxin T-2 on rat brain regional concentrations of serotonin, tryptophan, and tyrosine.

Female rats were given 1 acute dose or chronic doses (once every 48 hr for 28 days) of T-2 toxin (10 micrograms/kg ip) or vehicle. At necropsy, each brain was subdivided into cerebellum, cerebral cortex (including telencephalon and diencephalon), and brainstem (including mesencephalon, metencephalon, and myelencephalon). Acute systemic T-2 toxin administration increased cerebellar and brainstem tryptophan while serotonin, a tryptophan metabolite, was decreased correspondingly in these same brain regions.

Differential changes in rat brain tryptophan, serotonin and tyrosine levels following acute aflatoxin B1 treatment.

Female Sprague-Dawley rats were treated acutely (12-h) with aflatoxin B1 (100 micrograms/kg i.p.) or vehicle (10% acetone in 0.