Cardiorespiratory effects of a 5HT2 antagonist (R51703) in awake and anesthetized dogs.          下载免费PDF全文

T J Doherty  W N McDonell  D H Dyson  W D Black 《Canadian journal of veterinary research》1996,60(3):172-178

To investigate cardiorespiratory effects of an experimental 5-hydroxytryptamine receptor antagonist (R51703) with sedative properties, intramuscular doses of the drug were studied in 6 awake dogs of mixed breed, and in 6 anesthetized beagles. Two doses (0.2 and 0.4 mg/kg) of R51703 and a saline control were studied in the awake dogs using a randomized crossover trial. Subsequently, the higher dose of R51703 was included as a component of halothane anesthesia to determine whether the halothane sparing effect of R51703 produced a beneficial alteration of hemodynamic function. Data were obtained at equipotent halothane/R51703 (H/R) and halothane/saline (H/S) doses equivalent to 1.0, 1.5 and 2.0 MAC. In awake dogs, heart rates tended to be lower in dogs sedated with R51703, significantly so at 30 min for both doses, and at 90 and 120 min for the 0.2 and 0.4 mg/kg doses, respectively (P < 0.05). The cardiac index (CI) was lower at 60 min with both doses compared to the saline control group. Both doses of R51703 reduced mean blood pressure at 30, 90 and 120 min, and diastolic pressure at 30 and 90 min after administration; however, systolic blood pressure (SBP) was not altered. Overall, the cardiovascular alterations were minimal in conscious dogs and there was no evidence of respiratory depression. In the anesthetized dogs, at equipotent MAC, CI tended to be lower with H/R than with H/S, though the difference was not significant. Heart rate and stroke volume index also tended to be lower in the dogs treated with R51703, while systemic vascular resistance tended to be higher: these changes were not significant. Mean and SBP were higher at each MAC multiple in the H/R group. It was concluded that the halothane sparing effect of R51703 did not substantially improve hemodynamic function compared to the use of halothane alone at equipotent doses.  相似文献   

ARBOVIRUSES OF AUSTRALIA   总被引：6，自引：0，他引：6  

R. L. Doherty  M.B.  B.S.  M.P.H.  F.R.A.C.P.F.R.C.P.A. 《Australian veterinary journal》1972,48(4):172-180

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Effect of intravenous lidocaine and ketamine on isoflurane minimum alveolar concentration in goats     

MA Redua  T Doherty  P Castro-Queiroz  BW Rohrbach 《Veterinary anaesthesia and analgesia》2005,32(4):6-7

This study evaluated the effects of IV lidocaine (L) and ketamine (K), alone and in combination (LK), on the isoflurane MAC (ISO_MAC) in goats. It was hypothesized that L and K would reduce ISO_MAC and that the effect of LK would be additive. Eight adult goats (24–51 kg) were used in the study. Each goat was studied on four occasions, at weekly intervals, using a randomized crossover design. Anesthesia was induced with isoflurane (ISO) in O₂ and goats were intubated and ventilated to normocapnia. End‐tidal ISO (ET_ISO) and CO₂ were monitored with a calibrated infrared analyzer. Body temperature was maintained in the normal range using a heating pad. Approximately 45 minutes after intubation, and with the ET_ISO having been held constant for at least 20 minutes, determination of the baseline MAC (MAC_B) was initiated. A noxious stimulus, which consisted of clamping a claw between the jaws of a 10‐inch Vulsellum forceps, was administered for 60 seconds or until purposeful movement occurred. If purposeful movement occurred, the ET_ISO was increased by 0.1 vols% otherwise it was decreased by 0.1 vols% and the stimulus was reapplied following a 20 minute equilibration period. Following MAC_B determination treatments were administered as a loading dose (Ld) in 10 mL 0.9% NaCl over 3 minutes followed by a constant rate infusion to a final volume of 60 mL hour^–1 in 0.9% NaCl, as follows: L (Ld 2.5 mg kg^–1 + 100 μg kg^–1 minutes^–1); K (Ld 1.5 mg kg^–1 + 50 μg kg^–1minutes); LK or 0.9% NaCl. Post‐treatment MAC (MAC_T) determination began 45 minutes after the start of the loading dose. MAC_B and MAC_T were determined in triplicate and the mean value was used for data analysis. Difference in percent change in MAC was tested using a mixed‐model anova . Means separation among levels of treatment was tested using the Tukey‐Kramer method. The mean MAC_B for all treatments was 1.13 ± 0.03 vols%. L, K and LK reduced (p < 0.05) MAC_B by 19%, 49% and 69%, respectively. No change (p > 0.05) occurred with saline. It was concluded that L and K caused clinically significant decreases in ISO_MAC; however, the percent MAC reduction with L was less than expected given the MAC reduction reported with L for other species. The combination (LK) caused a profound decrease in ISO_MAC and this effect was additive.  相似文献   

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

Kelmer G  Doherty TJ  Elliott S  Saxton A  Fry MM  Andrews FM 《Equine veterinary journal》2008,40(4):358-363

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.  相似文献   

Pharmacokinetics and sedative effects of detomidine gel administered intravaginally in horses     

Reza Seddighi  Kaitlin Moorhead  Heather Knych  Sherry Cox  Xiacun Sun  Thomas Doherty 《Veterinary anaesthesia and analgesia》2018,45(6):885.e13-885.e14

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The effect of buprenorphine on isoflurane minimum alveolar concentration in dogs     

Patricia Queiroz‐Williams  Christine M Egger  Wen Qu  Barton W Rohrbach  Thomas Doherty 《Veterinary anaesthesia and analgesia》2014,41(3):312-318

ObjectiveTo determine the effect of intravenous (IV) buprenorphine on the isoflurane (ISO) minimum alveolar concentration (ISOMAC) in dogs.Study designRandomized, crossover, design.AnimalsSix healthy, adult (2–3 years old), intact dogs (two males and four females) weighing 7.4–11.0 kg.MethodsEach dog was studied on three occasions, 1 week apart, and baseline ISOMAC (MAC_B) was determined on each occasion. ISOMAC was defined as the mean of the end-tidal ISO concentrations that prevented and allowed purposeful movement in response to a noxious stimulus. After MAC_B determination, dogs were randomly given buprenorphine (BUP) at either 0.01, 0.05 or 0.1 mg kg^?1 IV, and ISOMAC was determined at two time periods after BUP administration. The first post-treatment determination (MAC_T1) was initiated 45 minutes after BUP administration and the second determination (MAC_T2) was initiated 4 hours after BUP administration. MAC values were determined in duplicate and the mean values were used for statistical analysis.ResultsIsoflurane minimum alveolar concentration was decreased at 141 minutes (the time of MAC_T1 determination) by 25%, 35%, and 27% after administration of BUP at 0.01, 0.05, and 0.1 mg kg^?1, respectively (p ≤ 0.05). The MAC reductions were not statistically different among doses. The reductions in ISOMAC at 342 minutes (the time of MAC_T2 determination) ranged from 13 to 16%, and were not statistically different among doses.Conclusions and clinical significanceBuprenorphine at 0.01, 0.05, and 0.1 mg kg^?1 significantly decreased ISOMAC in dogs at 141 minutes but not at 342 minutes. When using BUP for MAC reduction re-dosing may be required for procedures of long duration, and there may be no advantage to using the 0.1 mg kg^?1 dose.  相似文献   

Cavity quantum electrodynamics: coherence in context     

Mabuchi H  Doherty AC 《Science (New York, N.Y.)》2002,298(5597):1372-1377

Modern cavity quantum electrodynamics (cavity QED) illuminates the most fundamental aspects of coherence and decoherence in quantum mechanics. Experiments on atoms in cavities can be described by elementary models but reveal intriguing subtleties of the interplay of coherent dynamics with external couplings. Recent activity in this area has pioneered powerful new approaches to the study of quantum coherence and has fueled the growth of quantum information science. In years to come, the purview of cavity QED will continue to grow as researchers build on a rich infrastructure to attack some of the most pressing open questions in micro- and mesoscopic physics.  相似文献   

The influence of butorphanol dose on characteristics of xylazine-butorphanol-propofol anesthesia in horses at altitude     

Garcia Lascurain AA  Sumano Lopez H  Steffey EP  Santillán Doherty P  Hernandez EN 《Veterinary anaesthesia and analgesia》2006,33(2):104-110

OBJECTIVE: To characterize behavioral and physiological responses to short-term, unsupplemented intravenous (IV) anesthesia in healthy horses at high altitude (2240 m), and to test the hypothesis that the dose of butorphanol modifies the response of the horse to propofol anesthesia following xylazine pre-medication. STUDY DESIGN: Randomized prospective butorphanol dose cross-over experimental design. Animals Eight healthy horses, 13 +/- 6 (mean +/- SD) years of age, and weighing 523 +/- 26 kg. METHODS: Each horse was anesthetized three times with at least 3 weeks between each anesthesia. After collecting pre-drug data, xylazine (0.5 mg kg(-1)) was given IV. Five minutes later butorphanol was given IV according to a randomized order of three doses: 0.025, 0.05 and 0.075 mg kg(-1). Five minutes later, anesthesia was induced with propofol, 2 mg kg(-1) IV. Data on heart rate (HR) and respiratory rate (f(r)), mean arterial blood pressure, P(a)O(2), P(a)CO(2) and pH(a) were collected before, during and for 60 minutes following anesthesia, and quality of induction and recovery was scored. RESULTS: The pre-drug values for the three butorphanol groups did not differ. The combined pre-drug values from the 24 studies were HR, 33 +/- 7 beats minute(-1); f(r), 11 +/- 3 breaths minute(-1); P(a)O(2), 67 +/- 7 mmHg; P(a)CO(2), 36 +/- 4 mmHg; and pH(a), 7.42 +/- 0.04. Five minutes after anesthetic induction P(a)O(2) decreased and P(a)CO(2) increased 14.5 +/- 7.7 and 5.1 +/- 4.9 mmHg, respectively, but returned to pre-drug levels within 15 minutes of anesthetic recovery. There were no significant butorphanol dose-related differences in physiological results, anesthetic induction and recovery quality scores or recovery time. CONCLUSIONS AND CLINICAL RELEVANCE: Dose of butorphanol did not markedly influence study results. Notably, low P(a)O(2) values related to geographic location of study and general anesthesia indicates a narrow margin of error for hypoxemia-related complications in anesthetized horses breathing unsupplemented air at high altitude.  相似文献   

Extending Conifer Removal and Landscape Protection Strategies from Sage-grouse to Songbirds,a Range-Wide Assessment     

J. Patrick Donnelly  Jason D. Tack  Kevin E. Doherty  David E. Naugle  Brady W. Allred  Victoria J. Dreitz 《Strength and Conditioning Journal》2017,70(1):95-105

Recent and unprecedented scale of greater sage-grouse (Centrocercus urophasianus) conservation in the American West enables assessment of community-level benefits afforded to other sagebrush-obligate species. We use North American Breeding Bird Survey (BBS) count data and machine-learning to assess predictors influencing spatial distribution and abundance of three sagebrush-obligate songbirds (Brewer’s sparrow [Spizella breweri], sagebrush sparrow [Artemisiospiza nevadensis], and sage thrasher [Oreoscoptes montanus]). We quantified co-occurrence of songbird abundance with sage-grouse lek distributions using point pattern analyses and evaluated the concurrence of songbird abundance within sage-grouse habitat restoration and landscape protection. Sagebrush land-cover predictors were positively associated with the abundance of each songbird species in models that explained 16 ? 37% of variation in BBS route level counts. Individual songbird models identified an apparent 40% threshold in sagebrush land-cover, over which songbird abundances nearly doubled. Songbird abundances were positively associated with sage-grouse distributions (P < 0.01); range-wide, landscapes supporting > 50% of males on leks also harbored 13 ? 19% higher densities of songbirds compared with range-wide mean densities. Eighty-five percent of the conifer removal conducted through the Sage Grouse Initiative coincided with high to moderate Brewer’s sparrow abundance. Wyoming’s landscape protection (i.e., “core area”) strategy for sage-grouse encompasses half the high to moderate abundance sagebrush sparrow and sage thrasher populations. In the Great Basin half the high to moderate abundance sagebrush sparrow and sage thrasher populations coincide with sage-grouse Fire and Invasive Assessment Tool priorities, where conservation actions are being focused in an attempt to reduce the threat of wildfire and invasive plants. Our work illustrates spatially targeted actions being implemented ostensibly for sage-grouse largely overlap high abundance centers for three sagebrush obligate passerines and are likely providing significant conservation benefits for less well-known sagebrush songbirds and other sagebrush-associated wildlife.  相似文献