We compared the ability of 2 alpha2-adrenergic receptor antagonists, atipamezole and yohimbine, to reverse medetomidine-induced CNS depression and cardiorespiratory changes in lambs. Twenty lambs (7.8 +/- 2.6 kg) were randomly allotted to 4 treatment groups (n = 5). Each lamb was given medetomidine (30 micrograms/kg of body weight, IV), followed in 15 minutes by IV administration of atipamezole (30 or 60 micrograms/kg), yohimbine (1 mg/kg), or 0.9% NaCl (saline) solution. Medetomidine caused lateral recumbency in 1 to 2 minutes in all treated lambs. Medetomidine significantly (P < 0.05) decreased heart rate at 5 and 10 minutes after its administration. Heart rate remained above 120 beats/min, and severe bradycardia (< 70 beats/min) and other arrhythmias did not occur throughout the study. Medetomidine also induced tachypnea in all treated lambs. The tachypnea was abolished by atipamezole and yohimbine, but not by saline solution administration. The medetomidine-induced tachypnea did not significantly affect arterial pH and PaCO2. Arterial oxygen tension was within acceptable range (PaO2 = 71 to 62 mm of Hg), but was lower than expected. Administration of atipamezole, yohimbine, or saline solution did not change PaO2 significantly. Lambs treated with 30 or 60 micrograms of atipamezole/kg were able to walk unassisted in 2.4 +/- 0.4 and 2.3 +/- 0.7 minutes, respectively, whereas yohimbine-and saline-treated lambs did not walk unassisted until 15.6 +/- 2.7 and 73.0 +/- 6.8 minutes later, respectively. Results of this study indicated that medetomidine is a potent CNS depressant in lambs. Atipamezole at dosage of 30 or 60 micrograms/kg was equally effective, and was more effective in antagonizing medetomidine-induced CNS depression than was yohimbine.

Cardiorespiratory effects of abdominal insufflation were evaluated in 8 dogs during isoflurane anesthesia. Each dog was studied 3 times, in 1 of the following orders of insufflation pressures: 10-20-30, 20-30-10, 30-20-10, 10-30-20, 20-10-30, and 30-10-20 mm of Hg. Anesthesia was induced by use of a mask, dogs were intubated, and anesthesia was maintained by isoflurane in 100% oxygen. After instrumentation, baseline values were recorded (time 0), and the abdomen was insufflated with nitrous oxide. Data were recorded at 5, 10, 15, 20, 25, and 30 minutes after insufflation. The abdomen was then desufflated, with recording of data continuing at 35 and 40 minutes. Mean arterial pressure increased at 5 minutes during 20 mm of Hg insufflation pressure, and from 20 to 30 minutes during 30 mm of Hg pressure. Tidal volume decreased from 5 to 30 minutes during 10 and 20 mm of Hg pressures, and from 5 to 40 minutes during 30 mm of Hg pressure. Minute ventilation decreased at 10 and 20 minutes during 20 mm of Hg pressure. End-tidal CO2 concentration increased from 5 to 30 minutes during 20 and 30 mm of Hg pressure. The PaCO2 decreased at 40 minutes during 10 mm of Hg pressure, at 30 minutes during 20 mm of Hg pressure, and from 10 to 40 minutes during 30 mm of Hg pressure. Values for pH decreased from 10 to 30 minutes during 20 and 30 mm of Hg pressures. The PaO2 decreased from 20 to 40 minutes during 10 mm of Hg pressure, at 30 minutes during 20 mm of Hg pressure, and from 10 to 40 minutes during 30 mm of Hg pressure. Percentage decrease in tidal volume was greater at 5 and 15 minutes with 30 mm of Hg pressure. Differences in percentage increase in end tidal CO2 concentration were observed among the 3 pressures from 5 to 30 minutes. Although significant, these changes do not preclude use of laparoscopy if insufflation pressure > 20 mm of Hg is avoided.

Effects of IV and aerosol administration of 5-hydroxytryptamine (5-HT) on ventilation, pulmonary mechanics values, pulmonary arterial pressure, and heart rate were investigated in healthy unsedated Friesian calves. Minute volume increased significantly, mainly because of an increase in respiratory rate. Except for total pulmonary resistance after bolus injection, continuous administration of 5-HT given by either route caused significant alterations of lung dynamic compliance and total pulmonary resistance, the former decreasing to one-fifth of its baseline value and the latter increasing twofold. Pulmonary arterial pressure increased significantly, whatever the speed or route of administration. Administration of a bolus did not affect heart rate, whereas continuous iv administration of 5-HT as well by perfusion or by aerosol resulted in sustained tachycardia. It was concluded that 5-HT induces reversible bronchoconstriction and pulmonary vasoconstriction in healthy unsedated calves, 5-HT-induced functional alterations depend on the speed of administration, and excess of 5-HT production or depression in uptake by the lungs during bovine respiratory tract diseases could contribute to pulmonary dysfunction.

Health and ruminal variables were intensively measured during adaptation to grain-based diets in 6 beef cattle with fistulated rumens. The cows had been maintained on prairie grass hay-supplemented diets, and were converted to a grain-based finishing ration by feeding each successive diet (diets 1-4, respectively) for a period of 7 days. Each cow was evaluated and samples were obtained 3 times each day for the first 5 days that each diet was fed. Health variables monitored were rectal temperature, pulse, respiratory and rumen motility rates, fecal consistency, demeanor, blood pH, and blood glucose and L(+) lactate concentrations. Ruminal variables monitored were pH and glucose, DL-lactate, and volatile fatty acid concentrations of rumen contents. Data were analyzed by use of a multivariate ANOVA. We determined that most of the health variables were within reference rang limits throughout the adaptation period; however, analysis of pulse and respiratory rates indicated that diets 2 and 4 were stressful. Although blood pH continually decreased during feeding of the 4 diets (7.38 to 7.30), blood L(+) lactate and glucose concentrations had large increases only within diet 4. The pH of ruminal contents decreased progressively from 6.8 to 5.3. Rumen glucose concentration was low (< 1 micromole/ml), except with diet 4 in which values were 8 times higher than for other diets. By the end of the study, the ruminal contents of all animals were acidic (pH < 5.5), and, on the basis of higher than background amounts of ruminal glucose and DL-lactate, it was determined that rumen microbial equilibrium had not yet been achieved. Analysis of results of this study suggested that ruminal imbalance could be evaluated by monitoring pulse and respiratory rates, blood pH, and blood glucose concentrations. Assessment of the rumen alone could be accomplished by monitoring the variables of rumen pH, rumen glucose, and DL-lactate concentrations.

Tidal breathing flow-volume (TBFV) loops were determined in a group of control horses and in horses affected with recurrent airway obstruction (heaves). The latter group was studied when the condition was in remission and under increasing amounts of airway obstruction as reflected by measurements of change in pleural pressure, pulmonary resistance, and dynamic compliance. The TBFV loops of control horses had biphasic inspiratory and expiratory patterns; peak inspiratory and peak expiratory flows were detected early in inspiration and expiration, respectively. Tidal volume was unaffected by heaves, but at all stages of heaves, respiratory frequency was increased principally because of shorter inspiratory time, and therefore, inspiratory flow rate was increased. In horses with heaves, TBFV loops did not have a biphasic pattern; peak inspiratory flow was observed late in inspiration, and peak expiratory flow was observed early in expiration. As airway obstruction became more severe, peak expiratory flow increased as pulmonary resistance increased so that, during severe airway obstruction, TBFV loops had a characteristic appearance with high peak expiratory flow early in expiration followed by low flow rate.

Q fever (coxiellosis) is an infectious disease of animals and humans, caused by.C. burnetii and widely distributed throughout the world. It is known that people and animals acquire the disease predominantly.via inhalation of infectious aerosols. The possibility of transmission of the pathogen by the alimentary route is still a matter of debate and remains controversial. Therefore the aim of this study was to fill the gaps in knowledge of oral transmission of.C. burnetii by conducting biological tests on the guinea pig model. Guinea pigs, divided into five groups comprising a negative control and four experimental groups, received specified concentrations of.C. burnetii per os. To determine the presence of specific antibodies, blood samples were tested using CFT. Also, internal organs collected during necropsy were screened by a real-time PCR targeting I.1111. Additionally, histopathological evaluation of the tissues was performed. The presence of antibodies and pathogen DNA in caecum was confirmed in one guinea pig from experimental group IV..C. burnetii was also detected in testicular tissue collected from one animal of experimental group II. The presence of pathogen DNA in the testicular tissue indicates that infection spreads haematogenously. In the majority of experimental animals specific antibodies and genetic material of.C. burnetii were not detected. This fact suggests that development of infection depends on many factors, such as animal immune status.

Ozone is not harmful itself; however, it directly oxidises biomolecules and produces radical-dependent cytotoxicity. Exposure to ozone is by inhalation and therefore the lungs develop the main anti-inflammatory response, while ozone has an indirect impact on the other organs. This study investigated the local and systemic effects of the ozone-associated inflammatory response. Three groups each of 5 Wistar Han rats aged 6 months were exposed for 2h to airborne ozone at 0.5 ppm and a fourth identical group were unexposed controls. Sacrifice was at 3h after exposure for control rats and one experimental group and at 24 h and 48 h for the others. Lung and liver samples were evaluated for changes in expression of transforming growth factor beta 1, anti-inflammatory interleukin 10, pro-inflammatory tumour necrosis factor alpha and interleukin 1 beta and two nuclear factor kappa-light-chain-enhancer of B cells subunit genes. Total RNA was isolated from the samples in spin columns and cDNA was synthesised in an RT-PCR. Expression levels were compared to those of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and analysed statistically. All variables changed non-linearly over time comparing experimental groups to the control. Conspicuous expression changes in the subunit genes and cytokines were observed in both evaluated organs. Locally and systemically, inflammation responses to ozone inhalation include regulation of certain genes’ expression. The mechanisms are unalike in lungs and liver but ozone exerts a similar effect in both organs. A broader range of variables influential on ozone response should be studied in the future.

Several antidiabetic medications have been proposed as prospective treatments for cognitive impairments in type 2 diabetes patients, glibenclamide (GBC) among them. Our research aimed to evaluate the impact of GBC on hippocampal learning memory and inflammation due to enhanced neurotrophic signals induced by inhalation of sevoflurane. Rats (Sprague Dawley, both sexes) were assigned to four groups: a control (vehicle, p.o.), GBC (10 mg/kg b.w.; p.o.), low-dose sevoflurane and low-dose sevoflurane + GBC (10 mg/kg b.w.; p.o.) for 23 days. Terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining was performed to analyse the count of apoptotic cells and ELISA was conducted to assess the protein signals. A Western blot, a Y-maze test, and a Morris maze test were performed, and the results analysed. Blood and tissues were collected, and isolation of RNA was performed with qRT-PCR. The Morris maze test results revealed an improvement in the length of the escape latency on days 1 (P < 0.05), 2 (P < 0.01), 3, and 4 in the low-dose Sevo group. Time spent in the quadrant and crossing axis and the percentage of spontaneous alterations showed a substantial decrease in the low-dose Sevo group which received GBC at 10 mg/kg b.w. Significant increases were shown in IL-6 and TNF-α levels in the low-dose Sevo group, whereas a decrease was evident in the GBC group. Our results indicate that glibenclamide may be a novel drug to prevent sevoflurane inhalation-induced impaired learning and reduce brain-derived neurotrophic factor release, which may be a vital target for the development of potential therapies for cognitive deficits and neurodegeneration.

OBJECTIVE To determine the impact of mechanical ventilation (MV) and perfusion conditions on the efficacy of pulse-delivered inhaled nitric oxide (PiNO) in anesthetized horses. ANIMALS 27 healthy adult horses. PROCEDURES Anesthetized horses were allocated into 4 groups: spontaneous breathing (SB) with low (< 70 mm Hg) mean arterial blood pressure (MAP; group SB-L; n = 7), SB with physiologically normal (≥ 70 mm Hg) MAP (group SB-N; 8), MV with low MAP (group MV-L; 6), and MV with physiologically normal MAP (group MV-N; 6). Dobutamine was used to maintain MAP > 70 mm Hg. Data were collected after a 60-minute equilibration period and at 15 and 30 minutes during PiNO administration. Variables included Pao2, arterial oxygen saturation and content, oxygen delivery, and physiologic dead space-to-tidal volume ratio. Data were analyzed with Shapiro-Wilk, Mann-Whitney U, and Friedman ANOVA tests. RESULTS Pao2, arterial oxygen saturation, arterial oxygen content, and oxygen delivery increased significantly with PiNO in the SB-L, SB-N, and MV-N groups; were significantly lower in group MV-L than in group MV-N; and were lower in MV-N than in both SB groups during PiNO. Physiologic dead space-to-tidal volume ratio was highest in the MV-L group. CONCLUSIONS AND CLINICAL RELEVANCE Pulmonary perfusion impacted PiNO efficacy during MV but not during SB. Use of PiNO failed to increase oxygenation in the MV-L group, likely because of profound ventilation-perfusion mismatching. During SB, PiNO improved oxygenation irrespective of the magnitude of blood flow, but hypoventilation and hypercarbia persisted. Use of PiNO was most effective in horses with adequate perfusion.

OBJECTIVE To evaluate the effects of injectable dexmedetomidine-ketamine-midazolam (DKM) and isoflurane inhalation (ISO) anesthetic protocols on selected ocular variables in captive black-tailed prairie dogs (Cynomys ludovicianus; BTPDs). ANIMALS 9 zoo-kept BTPDs. PROCEDURES The BTPDs received dexmedetomidine hydrochloride (0.25 mg/kg, IM), ketamine hydrochloride (40 mg/kg, IM), and midazolam hydrochloride (1.5 mg/kg, IM) or inhalation of isoflurane and oxygen in a randomized complete crossover design (2-day interval between anesthetic episodes). Pupil size, globe position, tear production, and intraocular pressure measurements were recorded at 5, 30, and 45 minutes after induction of anesthesia. For each BTPD, a phenol red thread test was performed in one randomly selected eye and a modified Schirmer tear test I was performed in the other eye. Intraocular pressure was measured by rebound tonometry. RESULTS Compared with findings for the DKM protocol, pupil size was smaller at all time points when the BTPDs underwent the ISO protocol. Globe position remained central during anesthesia with the DKM protocol, whereas it varied among central, ventromedial, and ventrolateral positions during anesthesia with the ISO protocol. Tear production and intraocular pressure decreased significantly over time when the BTPDs underwent either protocol. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that ophthalmic examination findings for anesthetized BTPDs can be influenced by the anesthetic protocol used. The DKM protocol may result in more consistent pupil size and globe position, compared with that achieved by use of the ISO protocol. Tear production and intraocular pressure measurements should be conducted promptly after induction of anesthesia to avoid the effect of anesthetic episode duration on these variables.