Effects of 2.0% end-tidal isoflurane with and without atropine prior to dexmedetomidine administration on cardiovascular variables in dogs

The purpose of this study was to determine the cardiovascular effects of 2.0% end‐tidal isoflurane in dogs administered dexmedetomidine (DEX). Using a randomized crossover design and allowing at least 2 weeks between treatments 12 adult hound dogs of either sex weighing 22 ± 1.7 SD kg were anesthetized by face mask administration of either sevoflurane or isoflurane to facilitate instrumentation prior to administration of treatment drugs. Dogs were intubated and instrumented to enable measurement of heart rate (HR), systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures, mean pulmonary arterial pressure (PAP), pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), pulmonary arterial temperature (TEMP), and cardiac output (CO) via thermodilution using 5 mL of 5% dextrose, and recording the average of three replicate measurements. Cardiac index (CI) and systemic (SVR) and pulmonary vascular resistances were calculated. Following completion of instrumentation, dogs were allowed to recover for 40 minutes. After collection of baseline data, dogs were administered one of four treatments at T‐10 minutes prior to injection of DEX (500? g M^–2 IM): 1) saline (SAL); 2) atropine [ATR, 0.02 (n = 6) or 0.04 (n = 6) mg kg^–1 IM]; 3) ISO (2.0% end tidal concentration); or 4) ISO + ATR. Cardiovascular data were collected at T‐20 and T‐5 minutes prior to administration of DEX, and at 5, 10 , 20, 30, 40, and 60 min following DEX. Data were analyzed using anova for repeated measures with post‐hoc differences between means identified using Bonferroni's method (p < 0.05). Differences in ATR dose were not found to be significant and thus results for ATR dose groups were pooled. Administration of SAL (dexmedetomidine alone) was associated with decreases in HR and CO and increases in SAP, MAP, DAP, CVP, and SVR. Administration of ATR was associated with an increase in HR and CO compared with SAL. Administration of ISO was associated with an increase in HR and a decrease in SVR, MAP and CVP compared with SAL. Administration of ISO + ATR was associated with effects similar to that of ISO or ATR alone. We conclude that administration of ISO reduces the increase in SVR associated with administration of DEX and does not adversely affect CO.     

Influence of nitrogen on competition between cereals and their natural weed populations

The effects of nitrogen fertilizer on the growth and density of natural weed populations in spring barley (Hordeum vulgare L.) and winter wheat (Triticum aestivum L.) were investigated in the absence of herbicide. An increased level of applied nitrogen did not enhance: weed germination, tended to decrease the total weed biomass and had a differential effect upon the biomass of individual weed species in both wheat and barky. In competition with barley, Chenopodium album L. and Lamium spp. had lower nitrogen optima than the crop, while Urtica urens L. had a higher nitrogen optimum. In competition with wheat, Stellaria media (L.) Vill., Lamium spp. and Veronica spp. had lower nitrogen optima than the crop. The systematic changes in nitrogen effect with time were analysed by fitting orthogonal polynomials to the growth and density curves. The methodology could be recommended for other studies in which time or other systematic factors are included, as it supplies information which a traditional analysis of variance cannot provide. Since seed production is positively correlated with biomass, so nitrogen level affects seed production and, hence, the seed pool and future weed population, suggesting that fertilizer usage can be exploited in an integrated programme of crop: weed management. A trend towards lower N fertilizer application owing to concerns about the environment willfavour most of the weed species investigated in these experiments and change the composition of weed populations.     

Research progress on the role of melatonin and its receptors in animal reproduction: A comprehensive review

Melatonin and its receptors play a crucial role in the regulation of the animal reproductive process, primarily in follicular development. However, the role that melatonin performs in regulating hormones related with reproduction remains unclear. Melatonin and its receptors are present both in female and male animals’ organs, such as ovaries, heart, brain and liver. Melatonin regulates ovarian actions and is a key mediator of reproductive actions. Melatonin has numerous effects on animal reproduction, such as protection of gametes and embryos, response to clock genes, immune‐neuroendocrine, reconciliation of seasonal variations in immune function, and silence or blockage of genes. The growth ratio of reproductive illnesses in animals has raised a remarkable concern for the government, animal caretakers and farm managers. In order to resolve this challenging issue, it is very necessary to conduct state‐of‐the‐art research on melatonin and its receptors because melatonin has considerable physiognomies. This review article presents a current contemporary research conducted by numerous researchers from the entire world on the role of melatonin and its receptors in animal reproduction, from the year 1985 to the year 2017. Furthermore, this review shows scientific research challenges related to melatonin receptors and their explanations based on the findings of 172 numerous research articles, and also represents significant proficiencies of melatonin in order to show enthusiastic study direction for animal reproduction researchers.     

BRUCELLA CULTURES TYPED BY THE WHO BRUCELLOSIS CENTRE AT THE COMMONWEALTH SERUM LABORATORIES, MELBOURNE

Results of the typing of Brucella cultures received at the WHO Brucellosis Centre, CSL, Melbourne, from 1968-1976 are presented. The distribution of the biotypes of cultures recovered throughout Australia is shown on a host and State basis and atypical cultures are discussed. Cultures identified from Australia were Br. abortus, biotypes 1, 2 and 4 and Strain 19; Br. suis, biotype 1 and Br. ovis. Br. melitensis biotypes 1, 2 and 3 were recorded only as exotic human infections from the Mediterranean area and from laboratory infections. Br. abortus, biotype 1 was the most common bovine and human isolate and was found in horses, a goat and a sheep. There was a low incidence of Br. abortus, biotype 2 in cattle and it was found in 1 horse. Br. abortus, biotype 3 was not found in Australia but was submitted from Tanzania. Br. abortus, biotype 4 was rare in cattle and was found once in a horse. Br. abortus, Strain 19 was found occasionally in cattle and once from a test guinea pig. Br. suis, biotype 1 was found in both man and pigs in Queensland and New South Wales whereas biotype 3 was isolated only in New Guinea from pigs and cattle. Br. ovis was submitted from 3 States. Br. canis has not been found in Australia.     

Effect of pre-medication on gastroduodenoscopy in isoflurane-anesthetized cats

The pre‐medicant chosen may influence the ease with which gastroduodenoscopy (GD) is performed. The purpose of this study was to evaluate the relative ease of GD in cats under ketamine and isoflurane anesthesia after IM injection of hydromorphone (H, 0.1 mg kg^?1), hydromorphone plus glycopyrrolate (HG, 0.1 mg kg^?1 (H), 0.01 mg kg^?1 (G)), medetomidine (M, 0.03 mg kg^?1), or butorphanol (B, 0.4 mg kg^?1). Eight cats were assigned randomly to receive each treatment in a cross‐over design with at least 7 days between treatments. Twenty minutes after pre‐medication, medetomidine produced greater (p = 0.001) sedation than the other treatments when assessed, using a subjective ordinal scale. The cats were injected with ketamine (10 mg kg^?1 IM), orotracheally intubated, connected to a pediatric circle breathing system, and allowed to spontaneously breathe isoflurane in oxygen. Once end‐tidal isoflurane concentration was stable at 1.4% for 15 minutes, endoscopy was started. A single endoscopist (REG), who was unaware of the treatment used, performed all endoscopies. The endoscopist scored the difficulty of endoscopy subjectively (0–3). The significance of differences between treatments was evaluated using Friedman's test. Time for entering the stomach was 9.4 (4.7–15.9) (median (minimum–maximum)), 6.6 (5.2–11.7), 8.4 (6.3–16.5), and 7.7 (5.1–14.7) seconds and for entering the duodenum from the stomach was 20.5 (13.8–40.9), 18.2 (10.3–39.8), 20.2 (16.2–119.5), and 22.2 (11.8–83.8) seconds for H, HG, M, and B treatments, respectively. There were no significant differences in the time for, or difficulty of, endoscopy. We conclude that any of these drugs can be used satisfactorily at the doses and combinations tested to pre‐medicate cats prior to general anesthesia for GD.     

Nutritional responses in rainbow trout (Oncorhynchus mykiss) fed diets with different physical qualities at stable or variable environmental conditions

Rainbow trout with initial body weight 1144 g were fed two diets with high (feed A) or low (feed B) water stability for 6 weeks. During the last 2 weeks either stable or fluctuating oxygen saturation, salinity and temperature was introduced. High water stability of the feed was associated with harder pellets, less dust formation and less broken pellets compared to feed with low water stability. During the first 4 weeks, feed intake was 23% higher in trout fed diet B than in those fed diet A. Fluctuating environment resulted in a severe drop in feed intake for both dietary groups. At termination of the trial, stomachs of trout fed feed B contained mashed pellets and free water and oil. Stomachs of trout fed feed A contained more intact pellets and little fluid. The apparent digestibility of protein, starch, dry matter and energy was highest in feed A. The apparent digestibility of P and Zn was highest at stable environment, and the absorption of P was highest from feed A. In conclusion, physical quality affected the nutritional value of the feeds, and differences in nutritional value at stable or fluctuating environment appeared to be related to feed intake.     

Polycystic kidney disease in lambs in New Zealand

Extract

A lethal congenital polycystic kidney disease (PCKD) has been known in lambs in New Zealand for more than 50 years and assumed to be genetic in origin. We have studied this in lambs from an experimental mating in a flock experiencing an outbreak the previous year. Two Perendale rams identified by DNA profiling (SignaGen) as sires of PCKD lambs were each mated to the other's daughters. From 71 such matings, 10 ewes gave birth to 15 PCKD lambs of both sexes. The results are in accord with those expected for a recessive autosomal trait. All lambs were dead or died shortly after birth. Their abdomens were distended by enlarged kidneys 40–140 mm in length. Their cut surface showed a multitude of cystic spaces 1–5 mm in diameter in both the cortex and medulla. Livers of affected lambs showed complex tubular and cystic patterns of bile ducts containing bile, and supported by an excess of fibrous tissue. Cystic changes also occurred in the pancreas and salivary glands.     

Screening for the Mucopolysaccharidosis-IIIA gene in Huntaway dogs

Abstract

Extract

A single case of the inherited lysosomal storage disease known as mucopolysaccharidosis-IIIA (MPS-IIIA), due to a deficiency of the enzyme heparan sulphatase, was reported in an 18-month-old male Huntaway dog (Jolly et al 2000 Jolly, RD, Allan, FJ, Collett, MG, Rozaklis, T, Muller, VJ and Hopwood, JJ. 2000. Mucopolysaccharidosis IIIA (Sanfilippo syndrome) in a New Zealand Huntaway dog with ataxia. New Zealand Veterinary Journal, 48: 144–148. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]). He had developed normally but when presented with a history of progressive ataxia over the preceding month, had a high stepping, prancing gait and difficulty in jumping into a utility vehicle. In addition, he had started to defaecate in his kennel. Following diagnosis of the enzyme deficiency, the mutant heparan sulphatase gene was sequenced and a PCR/restriction enzyme diagnostic test developed, based on the mutation. This is capable of detecting both homozygous and heterozygous individuals (Yogalingam et al 2000 Yogalingam, G, Pollard, T, Gliddon, B, Jolly, RD and Hopwood, JJ. 2001. Identification of a mutation causing mucopolysaccharidosis type IIIA in New Zealand Huntaway dogs. Genomics, 79: 150–153.  [Google Scholar]).