Evaluation of Three Midazolam-Xylazine Mixtures Preliminary Trials in Dogs

The depressant effects of midazolam and xylazine on the central nervous system (CNS) were evaluated in 12 dogs. Xylazine was administered to six dogs (1.1 mg/kg intravenously [IV]) followed in 5 minutes by midazolam (1.0 mg/kg intramuscularly [IM]). In a second group of six dogs, xylazine (2.2 mg/kg IM) was followed in 5 minutes by midazolam (1.0 mg/kg IV). Both drug regimens induced rapid and profound sedation or anesthesia. Duration of action varied with the doses and routes of administration. Dogs given the high dose of xylazine IM had an arousal time of 95.4 +/- 8.9 minutes and a walking time of 155.4 +/- 8.8 minutes. These values exceeded the IV xylazine values threefold. Partial reversal of CNS depression was accomplished with either a benzodiazepine antagonist (flumazenil) or an alpha-2 antagonist (yohimbine). In a separate trial, a mixture of xylazine (0.55 mg/kg), midazolam (1.0 mg/kg), and butorphanol (0.1 mg/kg) with and without glycopyrrolate was evaluated in eight dogs. As with the xylazine-midazolam combinations, the CNS depressant effect of this mixture was clinically indistinguishable from anesthesia achieved with other rapid-acting injectable agents. Clinical signs of CNS depression were readily and completely antagonized by the simultaneous injection of flumazenil and yohimbine.     

Cardiopulmonary Effects of Using Carbon Dioxide for Laparoscopic Surgery in Dogs

Cardiopulmonary effects of laparoscopic surgery were investigated in five crossbred dogs (21 ± 1.9 kg). Premedicated dogs were anesthetized with thiopental and maintained with halothane at 1.5 times minimum alveolar concentration in oxygen. Controlled ventilation maintained partial pressure of end-tidal co₂ at 40 ± 2 mm Hg. Vecuronium was used for skeletal muscle relaxation. After instrumentation and stabilization, baseline measurements were made of cardiac output (thermodilution technique), mean systemic, mean pulmonary arterial and pulmonary wedge pressures, heart rate, saphenous vein and central venous pressures, and minute ventilation. Baseline arterial and mixed venous blood samples were drawn for analysis of pH, Pao₂, Paco₂, Pvo₂, Pvco₂, and bicarbonate concentrations. Systemic and pulmonary vascular resistances, oxygen delivery and consumption, shunt fraction, and dead space ventilation were calculated using standard formulas. Abdominal insufflation using co₂ to a pressure of 15 mm Hg for 180 minutes resulted in significant ( P <.05) increases in heart rate (15 to 180 minutes), minute ventilation (75 to 135 minutes), and saphenous vein pressure (15 to 180 minutes), and decreases in pH (60 to 180 minutes) and Pao₂ (60 to 180 minutes). For 30 minutes after desufflation, there was a significant decrease in Pao₂, and increases in cardiac output, o₂ delivery, and heart rate, compared with baseline. There was a significant increase in shunt fraction and decrease in pH at 15 minutes after desufflation only. The changes were within physiologically acceptable limits in these healthy, ventilated dogs.     

Quality of Reporting of Clinical Trials of Dogs and Cats and Associations with Treatment Effects

Background: To address concerns about the quality of reporting of randomized controlled trials, and the potential for biased treatment effects in poorly reported trials, medical journals have adopted a common set of reporting guidelines, the Consolidated Standards of Reporting Trials (CONSORT) statement, to improve the reporting of randomized controlled trials.
Hypothesis: The reporting of clinical trials involving dogs and cats might not be ideal, and this might be associated with biased treatment effects.
Animals: Dogs and cats used in 100 randomly selected reports of clinical trials.
Methods: Data related to methodological quality and completeness of reporting were extracted from each trial. Associations between reporting of trial features and the proportion of positive treatment effects within trials were evaluated by generalized linear models.
Results: There were substantive deficiencies in reporting of key trial features. An increased proportion of positive treatment effects within a trial was associated with not reporting: the method used to generate the random allocation sequence ( P < .001), the use of double blinding ( P < .001), the inclusion criteria for study subjects ( P = .003), baseline differences between treatment groups ( P = .006), the measurement used for all outcomes ( P = .002), and possible study limitations ( P = .03).
Conclusions and Clinical Importance: Many clinical trials involving dogs and cats in the literature do not report details related to methodological quality and aspects necessary to evaluate external validity. There is some evidence that these deficiencies are associated with treatment effects. There is a need to improve reporting of clinical trials, and guidelines, such as the CONSORT statement, can provide a valuable tool for meeting this need.     

Serum Pancreatic Lipase Immunoreactivity Concentrations in Dogs Treated with Potassium Bromide and/or Phenobarbital

Potassium bromide, phenobarbital, or a combination of both is commonly used in the treatment of canine epilepsy. Several cases of clinical pancreatitis have been reported in dogs after treatment with potassium bromide, but the risk of elevated serum canine pancreatic lipase immunoreactivity concentrations in dogs treated with potassium bromide and/or phenobarbital has not previously been evaluated in a large group of dogs. This study suggests an increased risk for elevated serum canine pancreatic lipase immunoreactivity concentrations and possibly pancreatitis in dogs treated with potassium bromide or phenobarbital alone or in combination.     

Full-thickness Thoracic and Abdominal Wall Reconstruction in Dogs Using Carbon/Polycaprolactone Composite

Square 9 × 9 cm full-thickness defects were created in the thoracic wall of five dogs and the abdominal wall of five dogs. The skin was retained. Ten centimeter squares of carbon fabric with a thin polycaprolactone (PCL) lining were sutured into the defects with the PCL lining facing the viscera. The dogs were observed for 5 months. The surgical technique was simple and fast. All implants were well tolerated. Cosmetic results were excellent in nine dogs. One dog (abdominal implant) developed an infection and draining tract, and a second dog (thoracic implant) had a subclinical infection. Thoracic implants caused brief serosanguinous pleural transudate. Mild paradoxical respiratory motion disappeared by 8 weeks. Lungs were radiographically normal. At necropsy, fibrous tissue was present but lacked orientation. Loose adhesions covered 20 to 80% of implant linings. There was no significant difference in ultimate tensile strength of implant/fibrous tissue compared to control abdominal wall. No carbon fragments were observed in lymph nodes. Increased numbers of secondary follicles, plasma cells, eosinophils, and sinus histiocytes in lymph nodes suggested immunologic stimulation of undetermined significance.     

Induction of Anesthesia Using Diazepam/Ketamine in Dogs with Complete Heart Block A Preliminary Report

Intravenous diazepam and ketamine were used to induce anesthesia in four dogs with complete heart block while cardiac and hemodynamic measurements were made. Immediately after induction there were minor changes in the measured variables. However, 5 minutes after injection, with the dogs supine and mechanically ventilated, cardiac output was reduced 41%. An additional 20 dogs with heart block had uncomplicated induction when this drug combination was used. The combination of diazepam and ketamine appears useful for inducing anesthesia in dogs with heart lesions, although further studies must be done to establish its value in such patients.     

Phase I & Ib Trials of Murine Tyrosinase ± Human GM‐CSF DNA Vaccination in Dogs with Advanced Malignant Melanoma

Introduction:  Canine malignant melanoma (CMM) is an aggressive neoplasm treated with surgery and/or fractionated RT; however, metastatic disease is common and chemoresistant. Preclinical and clinical studies by our laboratory and others have shown that xenogeneic DNA vaccination with tyrosinase family members can produce immune responses resulting in tumor rejection or protection and prolongation of survival. The potency of DNA vaccines can be further enhanced by adding DNA encoding cytokine genes. We have shown in preclinical mouse models that GM‐CSF DNA enhances immune responses and tumor protection. These studies provided the impetus for murine tyrosinase (muTyr) ± human GM‐CSF (huGM‐CSF) DNA vaccination in CMM.
Materials & Methods:  Two groups of five dogs each with advanced (WHO stage II‐IV) CMM received four biweekly IM injections (100 ug or 500 ug, respectively/vaccination) of plasmid DNA encoding muTyr via the Biojector2000 jet delivery device. Subsequently, three groups of nine dogs each with advanced CMM received four biweekly IM injections of plasmid DNA encoding muTyr (50 ug), huGM‐CSF (3 dogs each at 100/400/800 ug) or both.
Results:  Minimal to mild pain was noted on vaccination and no toxicity or induction of autoimmunity was seen. The KM median survival time was 224 days (100/500 ug muTyr), 278 days (50 ug muTyr), 140 days (huGM‐CSF) and >265 days (muTyr & huGM‐CSF; 6 dogs still alive).
Conclusions:  The results of these trials demonstrate that xenogeneic DNA vaccination continues to be a safe and potentially therapeutic modality for CMM. These results also warrant further evaluation of this novel therapeutic in a Phase II setting.     

Evaluation of the Cortisol‐to‐ACTH Ratio in Dogs with Hypoadrenocorticism,Dogs with Diseases Mimicking Hypoadrenocorticism and in Healthy Dogs

Background

The adrenocorticotropic hormone (ACTH) stimulation test is the gold standard for diagnosing hypoadrenocorticism (HA) in dogs. However, problems with the availability of synthetic ACTH (tetracosactrin/cosyntropin) and increased costs have prompted the need for alternative methods.

Objectives

To prospectively evaluate the cortisol‐to‐ACTH ratio (CAR) as a screening test for diagnosing canine HA.

Animals

Twenty three dogs with newly diagnosed HA; 79 dogs with diseases mimicking HA; 30 healthy dogs.

Methods

Plasma ACTH and baseline cortisol concentrations were measured before IV administration of 5 μg/kg ACTH in all dogs. CAR was calculated and the diagnostic performance of ACTH, baseline cortisol, CAR and sodium‐to‐potassium ratios (SPRs) was assessed based on receiver operating characteristics (ROC) curves calculating the area under the ROC curve.

Results

The CAR was significantly lower in dogs with HA compared to that in healthy dogs and in those with diseases mimicking HA (P < .0001). There was an overlap between HA dogs and those with HA mimicking diseases, but CAR still was the best parameter for diagnosing HA (ROC AUC 0.998), followed by the ACTH concentration (ROC AUC 0.97), baseline cortisol concentration (ROC AUC 0.96), and SPR (ROC AUC 0.86). With a CAR of >0.01 the diagnostic sensitivity and specificity were 100% and 99%, respectively.

Conclusion and Clinical Importance

Calculation of the CAR is a useful screening test for diagnosing primary HA. As a consequence of the observed overlap between the groups, however, misdiagnosis cannot be completely excluded. Moreover, additional studies are needed to evaluate the diagnostic reliability of CAR in more dogs with secondary HA.     

Euthanasia of small animals with nitrogen; comparison with intravenous pentobarbital

Intravenous pentobarbital (with or without addition of saturated potassium chloride) was compared with nitrogen gas exposure for euthanasia of small animals (dogs, cats, and rabbits) in a humane society environment. Initially, electrocardiographic) and electroencephalographic monitoring were used to establish the time of death in presedated animals given either pentobarbital or exposed to nitrogen; later, nitrogen euthanasia alone was studied. Sedation with acepromazine delayed the effects of nitrogen exposure. Addition of intravenous potassium chloride dramatically enhanced the effects of pentobarbital. When sedation was omitted, nitrogen was quantitatively as effective as pentobarbital alone. An adequate flow of nitrogen is essential and the concentration of oxygen in the euthanasia chamber must be monitored.     

雏鹅一氧化碳中毒的诊断与防制

一氧化碳主要是煤炭(或木炭)在缺氧条件下燃烧产生.在秋冬寒冷季节,养鹅户在育雏时,使用煤炉或木炭炉加温保暖,由于通风不良,造成了室内空气中的一氧化碳浓度过高,便会引起雏鹅发生中毒.     

Urinary Catecholamine and Metanephrine to Creatinine Ratios in Dogs with Hyperadrenocorticism or Pheochromocytoma,and in Healthy Dogs

Background: Urinary catecholamines and metanephrines are used for the diagnosis of pheochromocytoma (PHEO) in dogs. Hyperadrenocorticism (HAC) is an important differential diagnosis for PHEO. Objectives: To measure urinary catecholamines and metanephrines in dogs with HAC. Animals: Fourteen dogs with HAC, 7 dogs with PHEO, and 10 healthy dogs. Methods: Prospective clinical trial. Urine was collected during initial work‐up in the hospital; in dogs with HAC an additional sample was taken at home 1 week after discharge. Parameters were measured using high‐pressure liquid chromatography and expressed as ratios to urinary creatinine concentration. Results: Dogs with HAC had significantly higher urinary epinephrine, norepinephrine and normetanephrine to creatinine ratios than healthy dogs. Urinary epinephrine, norepinephrine, and metanephrine to creatinine ratios did not differ between dogs with HAC and dogs with PHEO, whereas the urinary normetanephrine to creatinine ratio was significantly higher (P= .011) in dogs with PHEO (414, 157.0–925.0, median, range versus (117.5, 53.0–323.0). Using a cut‐off ratio of 4 times the highest normetanephrine to creatinine ratio measured in controls, there was no overlap between dogs with HAC and dogs with PHEO. The variables determined in urine samples collected at home did not differ from those collected in the hospital. Conclusion and Clinical Importance: Dogs with HAC might have increased concentrations of urinary catecholamines and normetanephrine. A high concentration of urinary normetanephrine (4 times normal), is highly suggestive of PHEO.     

Corynebacterium spp. in Dogs and Cats with Otitis Externa and/or Media: A Retrospective Study

The role of Corynebacterium spp. in the pathogenesis of canine and feline otitis externa/media and their appropriate antimicrobial therapy are unclear. The objectives of this study were to (1) better establish the pathogenicity of Corynebacterium spp. in otitis utilizing reported criteria and by assessing clinical response to antibiotic therapy and (2) to determine the antimicrobial susceptibility patterns of Corynebacterium spp. associated with otitis. The study was retrospective, targeting cultures positive for Corynebacterium spp. Corynebacterium spp. were part of mixed microbial populations in 79/81 cultures. Corynebacterium spp. pathogenicity was highly questionable because of their almost invariable presence with other microbes and the observation that Corynebacterium spp. usually disappear from the ear with resolution of other infections, even when the Corynebacterium spp. are resistant to the prescribed antibiotic(s). However, 2/81 cultures came from two canine ears wherein Corynebacterium spp. may have been pathogenic. Antimicrobial sensitivities for Corynebacterium spp. were available for 54 isolates. Most isolates were susceptible to chloramphenicol (53/54), amikacin (50/54), tetracycline (50/54), gentamicin (46/54), and enrofloxacin (32/54). Among those antibiotics available in otic products, gentamicin and enrofloxacin would be rational choices for the empirical, topical therapy of Corynebacterium spp.     

Efficacy of Low‐Dose Human Chorionic Gonadotropin Therapy in Dogs with Spermatogenic Dysfunction: A Preliminary Study

Human chorionic gonadotropin (hCG) is a glycoprotein used in the treatment of spermatogenic dysfunction. However, previous studies performed in dogs show that repeated administration of large doses of hCG produces antibodies against hCG. In this study, we examined the efficacy of low‐dose injections of hCG in four male dogs with spermatogenic dysfunction and low plasma testosterone (T) levels. We administered 100 IU hCG per animal, five times at 3‐day intervals, and evaluated the changes in semen quality and plasma T levels. The total number of sperm in ejaculate, the percentage of progressively motile sperm and the plasma T levels had increased by 3–5 weeks after the first injection of hCG in three of the four dogs, but were unchanged in the fourth dog. These findings indicate that temporary improvement of the semen quality of dogs with spermatogenic dysfunction and low plasma T levels is possible after five low‐dose injections of hCG.     

Vaginal Microbiota of Spayed Dogs with or without Recurrent Urinary Tract Infections

Background

Limited information is available regarding the vaginal microbiota of normal spayed dogs and spayed dogs with recurrent UTIs. Vaginal lactic acid‐producing bacteria (LAB) have been associated with decreased frequency of recurrent urinary tract infection in women and may have a protective role within the urinary tract of female dogs.

Hypothesis/Objectives

Spayed dogs with historical recurrent UTI will have decreased prevalence of LAB and increased prevalence of uropathogenic bacterial populations in the vaginal microbiota when compared with the vaginal microbiota of healthy, spayed dogs.

Animals

Twenty‐one client‐owned adult spayed female dogs with historical recurrent UTI and 23 healthy, spayed female dogs without a history of recurrent UTI.

Methods

Dogs were placed into a recurrent UTI group or control group in this prospective study. Bacterial populations were isolated and characterized from vaginal swabs obtained from each dog.

Results

The most common bacterial isolates obtained from the vaginal tract of all dogs were Escherichia coli (11/44) and S. pseudintermedius (13/44). E. coli was isolated from the vaginal tract of 8 of 21 (38%) dogs in the rUTI group and 3 of 23 (13%) dogs in the control group (P = .08). LAB were isolated from 7 of the 44 dogs. Two of these 7 dogs were in the rUTI group and 5 of the 7 dogs were in the control group.

Conclusions and Clinical Importance

The vaginal microbiota of spayed female dogs with recurrent UTI was similar to the control population of normal, spayed female dogs.     

二氧化碳对鸡胚发育和孵化的影响

长期以来人们认为高CO2水平对家禽孵化是有害的,但近年来的研究显示在孵化的某些阶段高碳酸血对发育的胚胎是有利的.本文综述CO2对家鸡胚胎发育和孵化的影响,认为胚胎在发育的某些关键期需要CO2来增加胚胎的生长,刺激早期出雏,改善孵化率,提高出雏后生长.然而,不同孵化阶段对CO2耐受程度不同,需要进一步研究有利水平的适宜阶段和限度,以确定实际孵化生产中最佳的气体条件.