Pharmacokinetics of butorphanol in male neutered cats anesthetized with isoflurane.
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ABSTRACT:
SUBMITTER: Pypendop BH
PROVIDER: S-EPMC9293126 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Avian animals are visually inclined, which has caused them to attract increasing attention for visual neurophysiology or electrophysiology studies, including the study of the visual evoked potential (VEP). VEP has developed into an investigative tool for understanding the physiology and the pathology of the visual pathway. Chemical restraint is a common method to minimize motion artifacts in animals when acquiring VEP data, but little is known about its influence on the signal in an avian animal. In addition, it is difficult to make comparisons between conscious state data when the animals are ultimately under anesthesia. Therefore, finding drugs and developing protocols that have an acceptable effect is valuable. We compared the local field potentials of physically and chemically restrained zebra finches (Taeniopygia guttata), a small avian species, to simulate a relatively challenging recording condition. Finches were sedated with midazolam-butorphanol, and anesthesia was maintained by isoflurane. Electrodes were implanted into the left nucleus rotundus, which is a visual nucleus in birds. The VEPs of the control group (N = 3) were recorded after they fully recovered and were restrained by towels. The other birds (N = 3) were recorded under anesthesia. The results show that without the visual stimuli, anesthesia generally suppressed the overall power of field potentials. However, by focusing on the spectra during VEPs, visual stimuli still triggered significant VEPs in frequencies below 30.8 Hz, which were even stronger than towel-restrained birds. The drugs also prolonged the latency of the VEP, increased the duration of the VEP when compared to towel-restrained birds. As regard to towel-restrained zebra finches, the field potentials were less synchronized and may need data preprocessing to have clear VEPs. In conclusion, the current study presents evidence of basic VEP for zebra finch under midazolam-butorphanol-isoflurane anesthesia with a protocol that is a safe and feasible anesthetic combination for chemical restraint, which is particularly useful for small animals when obtaining evoked potentials.
| S-EPMC6815651 | biostudies-literature
Project description:The first aim of these studies was to compare growth patterns of healthy kittens neutered during growth with growth standards created for sexually-intact kittens. A second aim was to clarify the impact of neutering in kittens on body composition and body shape. Study 1 was a retrospective observational study comparing median growth trajectories of healthy, client-owned domestic shorthair (DSH) kittens in optimal body condition and neutered at different ages, with previously-created growth standards from a similar, sexually-intact, population. The neuter groups contained between 3.0k and 9.3k cats. For all neuter groups in both sexes, the median growth trajectory inclined upwards after the procedure, with this being more marked in female than in male kittens. This upwards inclination was less marked for kittens neutered later during growth in both sexes, with the effect being least in kittens neutered after 28-29 weeks. Study 2 was an analysis of new body composition and zoometric data from a previously-published randomised study, comparing growth-related measures between 11 pairs of sexually-intact and neutered (at 19 weeks age) female DSH cats in a research population. Before neutering, the growth pattern in neutered kittens and sexually-intact kittens was similar, but neutered kittens were heavier by 52 weeks (mean difference in fold change vs. 10 weeks 1.34, 95-CI: 1.07-1.72), had a greater fat mass (mean difference in fold change vs. 10 weeks 1.91, 95-CI 1.09-3.21) and greater lean mass (mean difference in fold change vs. 10 weeks 1.23, 95-CI: 1.03-1.48). Abdominal girth (mean difference in fold change vs. 10 weeks 1.20, 95-CI: 1.04-1.39) and rib cage length (mean difference in fold change vs. 10 weeks 1.18, 95-CI: 1.02-1.36) were also greater, but there were no differences in other zoometric measurements. Veterinarians should consider the potential impact that neutering has on gain of adipose tissue, especially early neutering in female kittens. Bodyweight should be monitored closely during growth and especially after neutering to prevent inappropriate weight gain.
| S-EPMC10016642 | biostudies-literature
Project description:BACKGROUND:Population-based, pharmacokinetic modeling can be used to describe variability in fluid distribution and dilution between individuals and across populations. The authors hypothesized that dilution produced by crystalloid infusion after hemorrhage would be larger in anesthetized than in awake subjects and that population kinetic modeling would identify differences in covariates. METHODS:Twelve healthy volunteers, seven females and five males, mean age 28 ± 4.3 yr, underwent a randomized crossover study. Each subject participated in two separate sessions, separated by four weeks, in which they were assigned to an awake or an anesthetized arm. After a baseline period, hemorrhage (7 ml/kg during 20 min) was induced, immediately followed by a 25 ml/kg infusion during 20 min of 0.9% saline. Hemoglobin concentrations, sampled every 5 min for 60 min then every 10 min for an additional 120 min, were used for population kinetic modeling. Covariates, including body weight, sex, and study arm (awake or anesthetized), were tested in the model building. The change in dilution was studied by analyzing area under the curve and maximum plasma dilution. RESULTS:Anesthetized subjects had larger plasma dilution than awake subjects. The analysis showed that females increased area under the curve and maximum plasma dilution by 17% (with 95% CI, 1.08 to 1.38 and 1.07 to 1.39) compared with men, and study arm (anesthetized increased area under the curve by 99% [0.88 to 2.45] and maximum plasma dilution by 35% [0.71 to 1.63]) impacted the plasma dilution whereas a 10-kg increase of body weight resulted in a small change (less than1% [0.93 to 1.20]) in area under the curve and maximum plasma dilution. Mean arterial pressure was lower in subjects while anesthetized (P < 0.001). CONCLUSIONS:In awake and anesthetized subjects subjected to controlled hemorrhage, plasma dilution increased with anesthesia, female sex, and lower body weight. Neither study arm nor body weight impact on area under the curve or maximum plasma dilution were statistically significant and therefore no effect can be established.
| S-EPMC6726118 | biostudies-literature
Project description:The main movement of the temporomandibular joint of dogs and cats is in vertical dimensions (opening and closing the mouth). An objective evaluation of the vertical mandibular range of motion (vmROM) may favor early diagnosis of a number of conditions affecting the joint mobility. vmROM, corresponding to the maximum interincisal opening, was measured in 260 dogs and 127 cats anesthetized between June 2011 and April 2015 because of oral or maxillofacial problems and procedures. Animals with a known history of or having current diseases considered to hamper mandibular extension were excluded from the study. Dogs were divided into four subgroups, based on body weight: subgroup 1 (?5.0?kg, 51 dogs), subgroup 2 (5.1-10.0?kg, 56 dogs), subgroup 3 (10.1-25?kg, 66 dogs), and subgroup 4 (>25.1?kg, 87 dogs). The mean vmROM of all dogs was 107?±?30?mm (median 109, range 40-180); in subgroup 1 was 67?±?15?mm (median 67, range 40-100), in subgroup 2 was 93?±?15?mm (median 93, range 53-128), in subgroup 3 was 115?±?19?mm (median 116, range 59-154), and in subgroup 4 was 134?±?19?mm (median 135, range 93-180). The mean vmROM of the cats was 62?±?8?mm (median 63, range 41-84). Correlations between vmROM, age, sex, and body weight were evaluated. In dogs, vmROM did not correlate with age, and in cats a weak positive correlation was found. vmROM and body weight were positively correlated in both populations, except dog subgroup 2. Overall, mean vmROM and body weight were significantly higher in male than in female, both in dogs and in cats. However, vmROM did not differ between sexes in any of the canine subgroups, and only in subgroup 4 male dogs were significantly heavier than females. Evaluation of vmROM should be incorporated into every diagnostic examination as it may be valuable in showing changes over time for every single patient.
| S-EPMC4923261 | biostudies-literature
Project description:Inhalation anesthetics (e.g. isoflurane) are preferable for longitudinal fMRI experiments in the same animals. We previously implemented isoflurane anesthesia for rodent forepaw stimulation studies, and optimized the stimulus parameters with short stimuli (1-3-s long stimulation with ten electric pulses). These parameters, however, may not be applicable for long periods of stimulation because repetitive stimuli induce neural adaptation. Here we evaluated frequency-dependent responses (pulse width of 1.0 ms and current of 1.5 mA) for 30-s long stimulation under 1.3-1.5% isoflurane anesthesia. The cerebral blood flow (CBF) response (using laser Doppler flowmetry: CBF(LDF)) and field potential (FP) changes were simultaneously measured for nine stimulus frequencies (1-24 Hz). CBF (using arterial spin labeling: CBF(ASL)) and blood oxygenation level dependent (BOLD) fMRI responses were measured at 9.4 T for four stimulus frequencies (1.5-12 Hz). Higher stimulus frequencies (12-24 Hz) produced a larger FP per unit time initially, but decreased more rapidly later due to neural adaptation effects. On the other hand, lower stimulus frequencies (1-3 Hz) induced smaller, but sustained FP activities over the entire stimulus period. Similar frequency-dependencies were observed in CBF(LDF), CBF(ASL) and BOLD responses. A linear relationship between FP and CBF(LDF) was observed for all stimulus frequencies. Stimulation frequency for the maximal cumulative neural and hemodynamic changes is dependent on stimulus duration; 8-12 Hz for short stimulus durations (<10s) and 6-8 Hz for 30-s stimulation. Our findings suggest that neural adaptation should be considered in determining the somatosensory stimulation frequency and duration under isoflurane anesthesia.
| S-EPMC2883664 | biostudies-literature
Project description:BackgroundOseltamivir phosphate (OP, Tamiflu(®)) is a widely used drug in the treatment of influenza with fever. However, case reports have associated OP intake with sudden abnormal behaviors. In rats infected by the influenza A virus (IAV), the electroencephalogram (EEG) displayed abnormal high-voltage amplitudes with spikes and theta oscillations at a core temperature of 39.9°C to 41°C. Until now, there has been no information describing the effect of OP on intact brain hippocampal activity of IAV-infected animals during hyperthermia.ObjectiveThe aim of the present study was to examine the effect of OP on abnormal EEG activities in the hippocampus using the rat model of influenza-associated encephalopathy.MethodsMale Wistar rats aged 3 to 4 weeks were used for the study. Influenza A/WSN/33 strain (1 × 10(5) plaque forming unit in PBS, 60 µL) was applied intranasally to the rats. To characterize OP effects on the IAV-infected rats, EEG activity was studied more particularly in isoflurane-anesthetized IAV-infected rats during hyperthermia.ResultsWe found that the hippocampal EEG of the OP-administered (10 mg/kg) IAV-infected rats showed significant reduction of the high-voltage amplitudes and spikes, but the theta oscillations, which had been observed only at >40°C in OP non-administered rats, appeared at 38°C core temperature. Atropine (30 mg/kg) blocked the theta oscillations.ConclusionOur data suggest that OP efficiently reduces the abnormal EEG activities after IAV infection during hyperthermia. However, OP administration may stimulate ACh release in rats at normal core temperature.
| S-EPMC4863546 | biostudies-literature
Project description:Suberoylanilide hydroxamic acid (SAHA), or vorinostat, is a histone deacetylase inhibitor approved for use as chemotherapy for lymphoma in humans. The goal of this study was to establish pharmacological parameters of SAHA in cats. Our interest in treating cats with SAHA is twofold: as an anticancer chemotherapeutic and as antilatency therapy for feline retroviral infections. Relying solely on data from studies in other animals would be inappropriate as SAHA is partially metabolized by glucuronidation, which is absent in feline metabolism. SAHA was administered to cats intravenously (2 mg/kg) or orally (250 mg/m², ~17 mg/kg) in a cross-over study design. Clinically, SAHA was well tolerated at these dosages as no abnormalities were noted following administration. The pharmacokinetics of SAHA in cats was found to be similar to that of dogs, but the overall serum drug exposure was much less than that of humans at an equivalent dose. The pharmacodynamic effect of an increase in acetylated histone proteins in blood was detected after both routes of administration. An increased oral dose of 60 mg SAHA/kg administered to one animal resulted in a surprisingly modest increase in peak drug concentration, suggesting possible saturation of absorption kinetics. This study provides a foundation for future studies of the clinical efficacy of SAHA in treating feline disease.
| S-EPMC3949138 | biostudies-other
Project description:Time- and vehicle-related variability of bladder and urethral rhabdosphincter (URS) activity as well as cardiorespiratory and blood chemistry values were examined in the acetic acid-induced bladder irritation model in α-chloralose-anesthetized female cats. Additionally, bladder and urethra were evaluated histologically using Mason trichrome and toluidine blue staining. Urodynamic, cardiovascular and respiratory parameters were collected during intravesical saline infusion followed by acetic acid (0.5%) to irritate the bladder. One hour after starting acetic acid infusion, a protocol consisting of a cystometrogram, continuous infusion-induced rhythmic voiding contractions, and a 5 min "quiet period" (bladder emptied without infusion) was precisely repeated every 30 minutes. Administration of vehicle (saline i.v.) occurred 15 minutes after starting each of the first 7 cystometrograms and duloxetine (1mg/kg i.v.) after the 8(th). Acetic acid infusion into the bladder increased URS-EMG activity, bladder contraction frequency, and decreased contraction amplitude and capacity, compared to saline. Bladder activity and URS activity stabilized within 1 and 2 hours, respectively. Duloxetine administration significantly decreased bladder contraction frequency and increased URS-EMG activity to levels similar to previous reports. Cardiorespiratory parameters and blood gas levels remained consistent throughout the experiment. The epithelium of the bladder and urethra were greatly damaged and edema and infiltration of neutrophils in the lamina propria of urethra were observed. These data provide an ample evaluation of the health of the animals, stability of voiding function and appropriateness of the model for testing drugs designed to evaluate lower urinary tract as well as cardiovascular and respiratory systems function.
| S-EPMC3767621 | biostudies-literature
Project description:The purpose of this study was to compare cardiovascular and respiratory effects of two volumes of bupivacaine 0.25% (0.2 mL kg-1-treatment BUP02-and 0.4 mL kg-1 -treatment BUP04) administered epidurally at the lumbosacral intervertebral space in dogs anesthetized with isoflurane. This experimental prospective randomized crossover design trial used six mixed breed adult dogs, four neutered males and two spayed females. Each dog was anesthetized on three different occasions: the first for isoflurane minimum alveolar concentration (MAC) measurement, and the following two assigned treatments (BUP02 or BUP04). On the two treatment days, anesthesia was induced and maintained with isoflurane at 1.3 MAC during the experiments. Cardiovascular and respiratory measurements were recorded before (T0) and 5, 15, 30, 60 and 90 minutes after the epidural administration of bupivacaine. Comparisons between and within groups were performed by a mixed-model ANOVA and Friedman's test when appropriate followed by Bonferroni post-hoc test or Dunnet's test to compare time points within each treatment with T0 (p < 0.05). Mean arterial pressure decreased significantly from 15 to 90 minutes after the administration of BUP02 and from 5 to 60 minutes in BUP04, with lower values in BUP04 than in BUP02 lasting up to 30 minutes after bupivacaine administration. No significant changes in cardiac output and systemic vascular resistance were observed in either treatment. Hypoventilation was only detected in BUP04. Hemoglobin concentration and arterial oxygen content decreased after both treatment of bupivacaine with no significant decrease in oxygen delivery. Two dogs in BUP04 developed Horner's syndrome. The epidural administration of 0.4 mL.kg-1 of bupivacaine to dogs in sternal recumbency anesthetized with isoflurane 1.3 MAC caused more cardiovascular and respiratory depression than 0.2 mL.kg-1.
| S-EPMC5906007 | biostudies-literature
Project description:Cats are the most common mammal to develop invasive fungal rhinosinusitis caused by cryptic species in Aspergillus section Fumigati that are resistant to azoles but susceptible to caspofungin. In this study nonlinear mixed-effects pharmacokinetic modeling and simulation was used to investigate caspofungin pharmacokinetics and explore dosing regimens in cats using caspofungin minimum effective concentrations (MECs). Plasma concentrations in healthy cats were determined using HPLC-MS/MS after administration of a single and seven consecutive daily intravenous doses of 1 mg/kg caspofungin. In the final pharmacokinetic model an optimum maximum concentration (Cmax): MEC ratio of 10-20 was used to guide caspofungin efficacy. Simulations were performed for dosing regimens (doses 0.25-2 mg/kg and 6-72 h dosing intervals) with and without inclusion of a loading dose. Using a 1 mg/kg dose Cmax first dose was 14.8 ?g/mL, Cmax at steady state was 19.8 ?g/mL, Cmin was 5 ?g/mL and Cmax: MEC was >20 in 42.6% of cats after multiple doses. An optimal Cmax: MEC ratio was achieved in caspofungin simulations using 0.75 mg/kg q 24 h or 1 mg/kg q 72h. However, at 1 mg/kg q 72h, Cmin was < MEC (<1 ?g/mL) in over 95% of the population. Using a loading dose of 1 mg/kg and a daily dose of 0.75 mg/kg thereafter, the Cmax: MEC was optimal and Cmin was > 2.5 ?g/mL for 98% of the population. Based on the modeling data this dosing regimen is likely to achieve target therapeutic concentrations, meet the proposed Cmax: MEC window and provide consistent exposure between doses.
| S-EPMC5456383 | biostudies-literature