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61.
Pharmacological management of feline hyperthyroidism offers a practical treatment option for many hyperthyroid cats. Two drugs have been licensed for cats in the last decade: methimazole and its pro‐drug carbimazole. On the basis of current evidence and available tablet sizes, starting doses of 2·5 mg methimazole twice a day and 10 to 15 mg once a day for the sustained release formulation of carbimazole are recommended. These doses should then be titrated to effect in order to obtain circulating total thyroxine (TT4) concentrations in the lower half of the reference interval. Treated cases should be monitored for side‐effects, especially during the first months of treatment. Some side‐effects may require discontinuation of treatment. At each monitoring visit, clinical condition and quality of life should also be evaluated, with special attention to possible development of azotaemia, hypertension and iatrogenic hypothyroidism. When euthyroidism has been achieved, monitoring visits are recommended after 1 month, 3 months and biannually thereafter. Cats with pre‐existing azotaemia have shorter survival times. However, development of mild azotaemia during the initial course of treatment, unless associated with hypothyroidism, does not appear to decrease survival time. The long‐term effects of chronic medical management require further study .  相似文献   
62.
The acid secretory capacity of the abomasal mucosa was studied in sheep experimentally infected with Ostertagia leptospicularis. The acidity of the abomasal contents, permanently recorded by a pH probe located inside the abomasum, decreased markedly to mean levels between pH 5 and 6. Subcutaneous administration of histamine or carbachol successfully stimulated acid secretion (pH 3.4). The results indicate that the abomasal mucosa harboured a population of functional parietal cells which were also identified immunohistochemically (H(+)/K(+)-ATPase). Ultrastructural investigation before stimulation revealed that the majority of these cells was in a resting state. Despite high serum gastrin levels, the acid secretion was blocked either at the level of the parietal cell or the enterochromaffin-like cell by an unknown factor, possibly mediated by the parasites. This is the first report of a parietal cell dysfunction associated with a nematode infection in the abomasum. It is suggested that the parasites induce changes in their environment which favour their survival and/or increase their reproduction.  相似文献   
63.
Lucerne (Medicago sativa L.) is an important temperate legume for livestock production systems. Lucerne requires a recovery period after a defoliation event so that taproot energy and nutrient stores can be replenished. A field experiment examined the effects of recovery period management following defoliation, on lucerne herbage production and nutritive value at two contrasting sites in Victoria, Australia. Sites were established at Rutherglen and Hamilton, using established SARDI Seven lucerne stands. Treatments were short recovery (SR; plots cut at 21‐day intervals), long recovery (LR; plots cut at 42‐day intervals), new shoots (NS; plots cut when new shoots from the crown were at least 2 cm long) and new shoots + flowering (NSF; as for NS but plots were left to grow to reach late flowering from late summer to mid‐autumn). At each defoliation, measurements were made of phenology, dry matter production and herbage nutrient concentrations (neutral detergent fibre, crude protein, metabolisable energy and water‐soluble carbohydrate %). Persistence was measured at approximately 6‐month intervals. At both sites, lucerne persisted equally well in all treatments although SR showed some decline at Hamilton at the final measurement. LR led to a more productive pasture (in terms of cumulative dry matter, neutral detergent fibre, crude protein, metabolisable energy and water‐soluble carbohydrate %) than the three other treatments. The results indicate that phenological management systems that allow lucerne to replenish reserves through late summer and autumn are unnecessary in mild winter environments.  相似文献   
64.
BACKGROUND: Hepatopathy in dogs with chronic respiratory diseases is poorly recognized. The aim of this study was to evaluate liver parameters alanine transferase, alkaline phosphatase, and glutamate dehydrogenase, as well as basal and stimulated bile acid concentration, in dogs with tracheal collapse. HYPOTHESIS: Dogs with tracheal collapse have hepatopathy. ANIMALS: 26 dogs with tracheal collapse. MATERIALS AND METHODS: Gall bladder contraction was stimulated by intramuscular injection of a synthetic cholecystokinin analogue (ceruletide). Twelve healthy Beagle dogs and 30 dogs of various breeds investigated previously without evidence of hepatic, gastrointestinal, or respiratory diseases served as control. Amelioration of liver variables was assessed after stent implantation. RESULTS: Twelve of 26 (46%) dogs had increased serum activity of 2 or more liver enzymes. Serum basal bile acid concentrations were high in 24 of 26 dogs. Twenty- and 40-minute stimulated bile acids were significantly higher in dogs with tracheal collapse (64.2 +130.0/-43.0 micromol/L and 82.6 +164.0/-57.1 micromol/L) compared to the control dogs (7.0 +/- 3.6 micromol/L and 6.4 +/- 3.5 micromol/L). All twelve dogs reevaluated after a median of 58 days (48-219 days) had a normal breathing pattern and significantly decreased 20 and 40 minutes stimulated bile acids (50.0 +92.7/-32.8 micromol/L, 52.8 +97.6/-34.3 micromol/L; P = .0043), whereas plasma liver enzyme activities were not significantly influenced. CONCLUSION AND CLINICAL IMPORTANCE: There was a significant hepatic dysfunction in the majority of dogs with a tracheal collapse. Liver function should be routinely assessed in dogs with severe respiratory disease.  相似文献   
65.
66.
Extracellular ligand binding to G protein-coupled receptors (GPCRs) modulates G protein and β-arrestin signaling by changing the conformational states of the cytoplasmic region of the receptor. Using site-specific (19)F-NMR (fluorine-19 nuclear magnetic resonance) labels in the β(2)-adrenergic receptor (β(2)AR) in complexes with various ligands, we observed that the cytoplasmic ends of helices VI and VII adopt two major conformational states. Changes in the NMR signals reveal that agonist binding primarily shifts the equilibrium toward the G protein-specific active state of helix VI. In contrast, β-arrestin-biased ligands predominantly impact the conformational states of helix VII. The selective effects of different ligands on the conformational equilibria involving helices VI and VII provide insights into the long-range structural plasticity of β(2)AR in partial and biased agonist signaling.  相似文献   
67.
Objectives: Evaluation of dogs with elevated plasma thyroxine concentration fed raw food before and after changing the diet. Method: Between 2006 and 2011 all dogs presented with an elevated plasma thyroxine concentration and a dietary history of feeding raw food were included. Thyroxine (reference interval: 19·3 to 51·5 nmol/L) and in many cases also thyroid-stimulating hormone concentrations (reference interval: <0·30 ng/mL) were measured initially and after changing the diet. Results: Twelve dogs were presented with a median age of five years. The median plasma thyroxine concentration was 156·1 (range of 79·7 to 391·9) nmol/L; in six dogs, thyroid-stimulating hormone concentration was measured and was <0·03 ng/mL in five dogs and 0·05 ng/mL in one dog. Six dogs showed clinical signs such as weight loss, aggressiveness, tachycardia, panting and restlessness while six dogs had no clinical signs. After changing the diet eight dogs were examined: thyroxine concentration normalised in all dogs and clinical signs resolved. Clinical Significance: Dietary hyperthyroidism can be seen in dogs on a raw meat diet or fed fresh or dried gullets. Increased plasma thyroxine concentration in a dog, either with or without signs of hyperthyroidism, should prompt the veterinarian to obtain a thorough dietary history.  相似文献   
68.
Thirty-one healthy pet cats had voided urine samples collected prior to, during and after a brief period of hospitalisation. Urinary corticoids were measured, both prior to and following an extraction technique, and the urinary corticoid:creatinine ratio (UCCR) was calculated. Associations between the UCCR and age, sex, breed and time of urine collection were investigated. There was no significant relationship established between age, sex and breed and the UCCR. A significant increase in the UCCR, however, did occur between the first home collected and first hospitalised urine sample, but only when comparing extracted corticoid results. A normal range for feline UCCR is established for the chemiluminescent immunoassay used in this study.  相似文献   
69.
70.
Twenty-four female Beagle dogs, 7-8 months old, were assigned to 4 groups. Control, low-dosage, medium-dosage, and high-dosage groups were offered 0, 1, 2, and 4 mg of sodium arsenite per kilogram of body weight per day (mg/kg/day), respectively, in their feed (equivalent to 0.0, 33.4, 66.7, and 133.4 micrograms/g in feed). On day 59, the dosage was doubled for the rest of the experiment, which ended on day 183. In general, arsenic concentrations in tissues and body fluids reflected arsenic levels in feed. Arsenic caused a dose-related decrease in food intake. Statistically significant differences in blood, liver, and kidney arsenic were detected, in most cases, between the 2 higher dosage groups and controls. The greatest differences in arsenic concentrations between groups were present in urine and hair. Results indicate that urine and hair would be the most useful specimens for chemical analysis when attempting to confirm low-level dietary inorganic arsenic exposure or poisoning.  相似文献   
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