Effects of lipopolysaccharide and phenylbutazone on gastric contents in the horse

REASONS FOR PERFORMING STUDY: Endotoxaemia causes a disruption of gastrointestinal motility in the horse but there is no information on its effects on gastric secretion. Lipopolysaccharide (LPS) administration is known to affect gastric secretion in other species. HYPOTHESIS: That LPS, a toxic component of Gram-negative bacteria, would reduce gastric acid secretion and that pretreatment with phenylbutazone (PBZ) would block the effects of LPS. METHODS: The effects of LPS and PBZ on gastric contents were investigated in fasted, mature horses, with permanent gastric cannulae. Horses were pretreated with either saline or PBZ 15 mins before a 60 min infusion of either LPS or saline. Gastric contents were collected at 15 min intervals for 3 h, beginning 15 mins after the start of the LPS or saline infusion. RESULTS: Lipopolysaccharide significantly decreased gastric acid output, [K+] and potassium output and increased [Na+] and sodium output. Phenylbutazone did not affect basal gastric acid secretion but decreased LPS-induced changes in the secreted volume, [Na+] and sodium output. CONCLUSIONS: This study provides evidence that LPS affects gastric acid secretion in the horse and that these LPS-induced changes are mediated, in part, by prostaglandins. POTENTIAL RELEVANCE: Lipopolysaccharide administration can induce changes in the composition of gastric contents in the horse but further work is needed to determine the source of these changes.     

Comparison of two injectable anesthetic regimes in feral cats at a large-volume spay clinic

Same‐day mass sterilization of feral cats requires rapid onset, short‐duration anesthesia. The purpose of this study was to compare our current anesthetic protocol, Telazol–ketamine–xylazine (TKX) with medetomidine–ketamine–buprenorphine (MKB). Feral female cats received either IM TKX (n = 68; 0.25 mL cat^?1; tiletamine 12.5 mg, zolazepam 12.5 mg, K 20 mg, and X 5 mg per 0.25 mL) or MKB (n = 17; M 40 µg kg^?1, K 15 mg kg^?1, and B 10 µg kg^?1). Intervals measured included time from injection to recumbency, time to surgery, duration of surgery, and time from reversal of anesthesia (TKX: yohimbine 0.50 mg cat^?1 IV; MKB: atipamezole 0.50 mg cat^?1 IM) to sternal recumbency. Following instrumentation (Vet/Ox 4403 and Vet/BP Plus 6500), physiological measurements were recorded at 5‐minute intervals, and included rectal temperature, heart rate (HR), respiratory rate (RR), SpO₂ (lingual or rectal probes), and indirect mean arterial blood pressure (MAP) (oscillometric method). Nonparametric means were compared using Mann–Whitney U‐tests. Parametric means were compared using a two‐factorial anova with Bonferroni's t‐tests. The alpha‐priori significance level was p < 0.05. Values were mean ± SD. Body weight (TKX: 2.9 ± 0.5 kg, MKB: 2.7 ± 0.7 kg), time to recumbency (TKX: 4 ± 1 minutes, MKB: 3 ± 1 minutes), time to surgery (TKX: 28 ± 7 minutes, MKB: 28 ± 5 minutes), and duration of surgery (TKX: 11 ± 7 minutes, MKB: 8 ± 5 minutes) did not differ between groups. In contrast, MKB cats required less time from reversal to sternal recumbency (TKX: 68 ± 41 minutes, MKB: 7 ± 2 minutes) and were recumbent for shorter duration (TKX: 114 ± 39 minutes, MKB: 53 ± 6 minutes). Temperature decreased during the study in both groups, but overall temperature was higher in MKB cats (38.0 ± 0.95 °C) than in TKX cats (37.5 ± 0.95 °C). RR, HR, and SpO₂ did not change during the study in either group. However, overall HR and RR were higher in TKX cats (RR: 18 ± 8 breaths minute^?1, HR: 153 ± 30 beats minute^?1) compared to MKB cats (RR: 15 ± 7 breaths minute^?1, HR: 128 ± 19 beats minute^?1). In contrast, overall SpO₂ was lower in the TKX group (90 ± 6%) compared to the MKB group (94 ± 4%). MAP was also lower in the TKX group (112 ± 29 mm Hg) compared to that in the MKB group (122 ± 20 mm Hg). However, MAP increased in the TKX group during surgery compared to pre‐surgical values, but did not change in the MKB group. The results of this study suggested that MKB might be more suitable as an anesthetic for the purpose of mass sterilization of feral female cats.     

Postpartum performance in a diallel cross among lines of mice selected for litter size and body weight

Postpartum dam performance was studied in a complete diallel design involving five lines of mice. The selection criterion in each line was: large litter size at birth (L+); large 6-wk body weight (W+); an index for large litter size and small 6-wk body weight (L+W-); the complementary index (L-W+) and random (K). Females from the five lines and 20 reciprocal F1 crosses were mated to sires of a randomly selected control line (CC). Correlated responses in average direct genetic and average maternal genetic effects for dam body weight and litter size at parturition persisted throughout lactation, indicating important pleiotropic effects. Major correlated responses occurred for litter weight, feed intake and litter feed efficiency, primarily due to average direct genetic effects. Using general combining ability and net line effects as criteria for choosing among lines, L+ had a distinct advantage if the objective was to increase litter size in a crossing program. If the objective was to maximize litter weaning weight, then W+ would be favored for net line effects, while L+ and W+ would be about equivalent for general combining ability. None of the lines had an advantage for litter feed efficiency. Direct heterosis for dam weight at 12 and 21 d of lactation averaged 2.7 and 1.9%, while for litter size the respective averages were 7.4 and 7.3%. The W+ X L+W- cross exhibited overdominance for litter size. Direct heterosis was moderate for feed intake and litter weight, but was negligible for litter feed efficiency because of the mathematical relationship among the three traits. Maternal heterosis for preweaning progeny growth was suppressed because of heterosis for litter size in the dam. Grand-maternal effects on growth of the young were small and would not be an important consideration in choosing among these lines in a crossbreeding program.     

Evaluation of dimethyl sulphoxide effects on initial response to endotoxin in the horse

REASONS FOR PERFORMING STUDY: Endotoxaemia is one of the most severe and ubiquitous disease processes in horses. Although dimethyl sulphoxide (DMSO) is used clinically in horses, there is no study indicating its efficacy in endotoxaemic horses. HYPOTHESIS: DMSO ameliorates the clinical response to i.v. lipopolysaccharide (LPS) administration. METHODS: Eighteen horses were assigned randomly to one of 4 groups: Normosol-LPS (0.2 mug/kg bwt, i.v.); DMSO (1 g/kg bwt, i.v.)-saline; high-dose DMSO (1 g/kg bwt, i.v.)LPS; low-dose DMSO (20 mg/kg bwt, i.v.)-LPS. Horses participating in the DMSO-saline group were later assigned randomly to one of the LPS groups. Data for physical parameters, white blood cell counts, plasma TNF-alpha, and blood lactate and glucose concentrations were examined for the effect of treatment using a repeated-measures mixed-model ANOVA. A value of P<0.05 was considered significant. RESULTS: Endotoxaemia occurred in all horses receiving LPS, as indicated by the clinical score, physical parameters, haemoconcentration and leucopenia. High-dose DMSO ameliorated the effect of LPS on fever. DMSO, at either dose, but did not have a significant effect on LPS-induced changes in all other evaluated parameters. CONCLUSIONS: In this study, DMSO had minimal effects on clinical signs of induced endotoxaemia in horses. The effects were manifested by amelioration of LPS-induced fever.     

Effects of buprenorphine,butorphanol or tramadol premedication on anaesthetic induction with alfaxalone in common marmosets (Callithrix jacchus)

Objective

To investigate the clinical and physiological effects of intravenous (IV) alfaxalone alone or in combination with buprenorphine, butorphanol or tramadol premedication in marmosets.

Diameter-Selective Raman Scattering from Vibrational Modes in Carbon Nanotubes

Single wall carbon nanotubes (SWNTs) that are found as close-packed arrays in crystalline ropes have been studied by using Raman scattering techniques with laser excitation wavelengths in the range from 514.5 to 1320 nanometers. Numerous Raman peaks were observed and identified with vibrational modes of armchair symmetry (n, n) SWNTs. The Raman spectra are in good agreement with lattice dynamics calculations based on C-C force constants used to fit the two-dimensional, experimental phonon dispersion of a single graphene sheet. Calculated intensities from a nonresonant, bond polarizability model optimized for sp2 carbon are also in qualitative agreement with the Raman data, although a resonant Raman scattering process is also taking place. This resonance results from the one-dimensional quantum confinement of the electrons in the nanotube.     

Growth,survival, and competitive ability of chestnut (<Emphasis Type="Italic">Castanea</Emphasis> Mill.) seedlings planted across a gradient of light levels

There has been an increased interest in tree breeding for resistance to exotic pests and pathogens, however relatively little research has focused on the reintroduction of these tree species. Understanding the durability of resistance in field settings and the field performance of improved trees is critical for successful species reintroduction. To evaluate methods for reintroducing American chestnut [Castanea dentata (Marsh.) Borkh] to managed forests on the Cumberland Plateau, we quantified four-year survival and growth and three-year competitive ability of chestnut seedlings planted on the Daniel Boone National Forest in southeastern Kentucky, USA. We used a split-plot design to compare chestnut response among three silvicultural treatments spanning a gradient of light levels; midstory removal, thinning, and shelterwood with reserves (2, 24, and 65% available photosynthetically active radiation, respectively) and three chestnut breeding types; American, Chinese (C. mollissima Blume.), and BC₂F₃ hybrid. One of two hybrid families planted had similar survival to American chestnuts, 21 and 27% survival, respectively, while the other had better survival, 57%. Chinese chestnut survival was better than the other breeding generations (90%). High mortality among American and hybrid chestnut seedlings was likely caused by infection from Phytophthora cinnamomi Rands. Incidence of blight infection was low. While chestnut seedling growth was greatest in the high-light treatment, competitive ability of chestnut, evaluated by comparing planted seedling height to height of understory competitors, was maximized in the intermediate light treatment. These results demonstrate the importance of evaluating competition pressure from co-occurring vegetation and field performance of resistant genotypes when assessing methods for reintroducing tree species to forested settings.