Sarcocystis neurona reacting antibodies in Missouri feral domestic cats (Felis domesticus) and their role as an intermediate host.

Sarcocystis neurona is the parasite associated with equine protozoal myeloencephalitis (EPM). Recently, cats (Felis domesticus) have been implicated as a potential intermediate host in the life cycle of S. neurona. This study was initiated to determine whether cats have antibodies that react to S. neurona antigens similar to antibodies from horses with EPM, and to evaluate the role of cats as intermediate hosts in the parasite's life cycle. Nine feral cats were used for analysis. Only one had antibodies reacting to S. neurona antigens. Muscle tissue from this cat, with detectable sarcocysts in the tongue, was fed to an opossum (Didelphis virginiana). The opossum shed sporocysts, which were then fed to gamma-interferon receptor knockout mice. Histopathology, immunohistochemistry, parasite isolation and molecular analysis were used to examine the pathology and associated parasites in the mice. The study suggests that the domestic cat can serve as an intermediate host to S. neurona or a S. neurona-like organsim.

A multisite case report on the clinical use of sevoflurane in dogs.

The purpose of this report was to evaluate the clinical safety and efficacy of sevoflurane as an inhalant anesthetic in dogs. Subjective and objective data from 196 clinical cases utilizing sevoflurane as the maintenance anesthetic was collected at three sites. After preanesthetic evaluation, the attending anesthesiologist assigned the dogs to one of the following six anesthetic protocols: protocol 1, oxymorphone premedication and thiopental induction; protocol 2, oxymorphone/acetylpromazine premedication and thiopental induction; protocol 3, xylazine/butorphanol premedication and thiopental induction; protocol 4, opioid premedication and propofol induction; protocol 5, optional premedication and mask induction with sevoflurane in oxygen; and protocol 6, optional premedication and optional induction. The average quality of induction, maintenance, and recovery was good to excellent in all protocols. The three most common side effects during maintenance and recovery were hypotension, tachypnea, and apnea. Sevoflurane produces anesthesia in dogs comparable to the other inhalation anesthetics currently used (i.e., halothane and isoflurane) for diagnostic or therapeutic procedures.

Inhaled carbon monoxide concentration during halothane or isoflurane anesthesia in horses.

OBJECTIVE: The purpose of this study was to assess carbon monoxide (CO) exposure during equine anesthesia with either halothane (H) or isoflurane (I) delivered in a circle rebreathing system. STUDY DESIGN: Prospective clinical investigation. ANIMALS: Fifty client-owned horses. METHODS: Horses were randomly assigned for anesthetic maintenance with H (n = 26) or I (n = 24). Two large animal anesthetic machines were used and assigned to a single agent for 2-4 weeks at a time. Machines were disassembled and soda lime changed prior to switching anesthetic agents. Inhalant anesthetic concentration and CO concentration were measured in gas samples obtained from the inspiratory limb of the anesthetic circuit. Values were recorded at 15 minute intervals for 90 minutes. Soda lime status (new or used) and mode of ventilation (spontaneous or mechanical) were also recorded. Data were analyzed using a five-factor ANCOVA with repeated measures. RESULTS: Inspired CO concentration for H and I increased from 1 +/- 3 and 6 +/- 11 ppm at baseline to 54 +/- 33 and 21 +/- 18 ppm at 90 min, respectively (mean +/- sd). H was associated with significantly greater CO concentrations than I at 30 to 90 min, although baseline CO was significantly greater in the I group than the H group. Oxygen flow rates were 9.9 +/- 0.5 L/min at baseline for H and I, and 5.0 +/- 0.4 and 5.0 +/- 0.7 L/min at 90 min for H and I, respectively. There were no significant differences between groups for O2 flow at any time point. Neither mechanical ventilation nor new versus used soda lime affected CO concentration. CONCLUSIONS: Significantly higher concentrations of CO were recorded during the administration of H than I. CLINICAL RELEVANCE: Levels of CO observed during the administration of either H or I for 90 minutes to horses were not clinically significant.

Effects of intramuscular sedative and opioid combinations on tear production in dogs.

The effect of commonly used sedation protocols on tear production rate was evaluated in dogs. Schirmer I tear tests were examined before and after intramuscular injection of acepromazine and oxymorphone (ACE + OXY; n = 7), diazepam and butorphanol (DIA + BUT; n = 8), and xylazine and butorphanol (XYL + BUT; n = 8). Two Schirmer I tear tests were also performed 15-25 min apart in dogs which received no sedative drugs (control; n = 4). Tear production rate decreased to 15 +/- 2, 17 +/- 1, and 6 +/- 1 mm min-1, respectively, while control animals averaged 21 +/- 2 mm min-1 at the same time point. Because XYL + BUT profoundly decreased tear production rate, we evaluated the two drugs separately. While BUT mildly decreased tear production when given alone to dogs (18 +/- 1 mm min-1; n = 5), xylazine had no effect on tear production. Thus it appears that the two agents act synergistically to decrease tear production rate in dogs. Moreover, sterile ocular lubricant or tear replacement should be used during XYL + BUT sedation.

Evaluation of an oscillometric blood pressure monitor on anesthetized cats and the effect of cuff placement and fur on accuracy.

OBJECTIVES: (1) To determine the usefulness of one specific oscillometric monitor for making indirect measurements of arterial pressure in cats. (2) To determine the difference between two specific cuff placement sites. (3) To determine if clipping the hair beneath the cuff has an affect on the accuracy of oscillometric blood pressure determination. STUDY DESIGN: Prospective study comparing the accuracy of the Datascope Passport (Datascope Corp, Paramus, NJ) with concurrent invasive measurements. ANIMALS: Six anesthetized domestic felines weighing 4.5 to 5 kg. METHODS: The direct arterial pressure was measured using a cannula placed in the right common carotid artery. Oscillometric cuffs of appropriate size were placed on both thoracic limbs distal to the elbow and both pelvic limbs distal to the stifle. The hair in the areas of cuff placement on the right limbs was clipped circumferentially. Measurements of systolic, diastolic, and mean arterial pressure (MAP) were taken for each site during normotension, hypotension, and hypertension. Comparisons between indirect and direct measurements were made using a parametric analysis of method comparison. RESULTS: No significant differences were noted when the clipped limbs were compared with the corresponding limbs which were left unclipped (P > .378) or when the thoracic limb measurements were compared with those of the pelvic limb (P > .088). There were significant differences (P < or = .002) between the two pressure measurement methods for the systolic, diastolic, and mean arterial pressures over all three pressure ranges. CONCLUSIONS: The Datascope Passport did not accurately estimate the invasively measured arterial pressure. CLINICAL RELEVANCE: Use of noninvasive blood pressure monitoring equipment is increasing in use in veterinary medicine, and the accuracy of one specific monitor is reported.

Evaluation of pulse oximeter probes and probe placement in healthy dogs.

Placement of two different pulse oximeter probes, a finger (f) probe and a multisite (s) probe, was evaluated in six healthy, anesthetized beagles. Concurrent arterial blood gas values were compared to determine the most consistent (repeatable) and accurate (compared to calculated hemoglobin saturations) pulse oximeter probe and probe placement sites for subsequent use in awake dogs. Hemoglobin oxygen saturation was determined from arterial blood gas analysis (SaO2) and by pulse oximetry (SpO2) at full hemoglobin saturation (mean, 99.5% SaO2) and at moderate desaturation (mean, 92.9% SaO2). Each probe was evaluated with three independent readings at seven different body sites (Achilles, ear, flank, lip, tail, toe, and tongue). Values for SpO2 obtained with the s probe demonstrated a significant correlation with SaO2 values (p = 0.014, R = 0.712) compared to the SpO2 values obtained with the f probe (p = 0.108). The best probe placement sites for the clip-on probes in this study were on the lip and tongue using the s probe; however, the ear, tail, and toe may be acceptable sites in awake dogs using a probe which maintains good contact across these vascular beds.

Use of an ultrasonic Doppler flow detector for determining tissue viability in a dog.

An 8-month-old sexually intact female Boxer was examined because of an almost complete disarticulation of the right thoracic limb at the level of the proximal phalanges. Viability of the tissue distal to the injury was considered questionable. An ultrasonic Doppler flow detector was used to determine that circulation to the portion of the digits distal to the injury had been preserved on the palmar aspect of the foot. Orthopedic repair of the fractures of the third and fourth digits and primary skin closure of the wound was performed. Infection and instability at the fracture sites resulted in pseudoarthrosis and a valgus deformity of the digits distal to the injury. The ultrasonic Doppler flow detector provided a simple noninvasive method for determining tissue viability in the severely traumatized foot of this dog.

Ketamine, Telazol, xylazine and detomidine. A comparative anesthetic drug combinations study in ponies.

This study was designed to assess the effects of 5 anesthetic drug combinations in ponies: (1) ketamine 2.75 mg/kg, xylazine 1.0 mg/kg (KX), (2) Telazol 1.65 mg/kg, xylazine 1.0 mg/kg (TX), (3) Telazol 2 mg/kg, detomidine 20 micrograms/kg (TD-20), (4) Telazol 2 mg/kg, detomidine 40 micrograms/kg (TD-40), (5) Telazol 3 mg/kg, detomidine 60 micrograms/kg (TD-60). All drugs were given iv with xylazine or detomidine preceding ketamine or Telazol by 5 min. Heart rate was decreased significantly from 5 min to arousal after TD-20 but only at 60 and 90 min after TD-40 and TD-60 respectively. Respiratory rate was decreased significantly for all ponies. Induction time did not differ between treatments. Duration of analgesia was 10 min for KX, 22.2 min for TX, 27.5 min for TD-20, 32.5 min for TD-40, and 70 min for TD-60. Arousal time was significantly longer with detomidine and Telazol. Smoothness of recovery was judged best in ponies receiving KX and TD-40. All ponies stood unassisted 30 min after signs of arousal.