Fluorinated analogues of chrysanthemic acid

Novel halogenated chrysanthemic acid analogues have been prepared and the interesting properties of their esters are described. Among this group are the most active insecticides yet reported.     

The effects of ketamine on the minimum alveolar concentration of isoflurane in cats

OBJECTIVES: To determine the minimum alveolar concentration (MAC) of isoflurane during the infusion of ketamine. STUDY DESIGN: Prospective, experimental trial. ANIMALS: Twelve adult spayed female cats weighing 5.1 +/- 0.9 kg. METHODS: Six cats were anesthetized with isoflurane in oxygen, intubated and attached to a circle-breathing system with mechanical ventilation. Catheters were placed in a peripheral vein for the infusion of fluids and ketamine, and the jugular vein for blood sampling for the measurement of ketamine concentrations. An arterial catheter was placed to allow blood pressure measurement and sampling for the measurement of PaCO2, PaO2 and pH. PaCO2 was maintained between 29 and 41 mmHg (3.9-5.5 kPa) and body temperature was kept between 37.8 and 39.3 degrees C. Following instrumentation, the MAC of isoflurane was determined in triplicate using a tail clamp method. A loading dose (2 mg kg(-1) over 5 minutes) and an infusion (23 microg kg(-1) minute(-1)) of ketamine was started and MAC was redetermined starting 30 minutes later. Two further loading doses and infusions were used, 2 mg kg(-1) and 6 mg kg(-1) with 46 and 115 microg kg(-1) minute(-1), respectively and MAC was redetermined. Cardiopulmonary measurements were taken before application of the noxious stimulus. The second group of six cats was used for the measurement of steady state plasma ketamine concentrations at each of the three infusion rates used in the initial study and the appropriate MAC value determined from the first study. RESULTS: The MAC decreased by 45 +/- 17%, 63 +/- 18%, and 75 +/- 17% at the infusion rates of 23, 46, and 115 microg kg(-1) minute(-1). These infusion rates corresponded to ketamine plasma concentrations of 1.75 +/- 0.21, 2.69 +/- 0.40, and 5.36 +/- 1.19 microg mL(-1). Arterial blood pressure and heart rate increased significantly with ketamine. Recovery was protracted. CONCLUSIONS AND CLINICAL RELEVANCE: The MAC of isoflurane was significantly decreased by an infusion of ketamine and this was accompanied by an increase in heart rate and blood pressure. Because of the prolonged recovery in our cats, further work needs to be performed before using this in patients.     

The effect of the duration of propofol administration on recovery from anesthesia in cats

OBJECTIVE: To determine the effect of induction, a 30-minute, and a 150-minute infusion of propofol on the rate of recovery in cats. STUDY DESIGN: Randomized, cross-over, prospective experimental study. ANIMALS: Six healthy adult spayed female cats (mean 4.3, range 2-7 years old) weighing 3.9 +/- 0.5 kg. METHODS: Cats received each of three treatments: anesthetic induction with propofol (T1), induction followed by a 30-minute infusion (T30) and induction followed by a 150-minute infusion (T150). Propofol infusions were increased or decreased to maintain a sluggish pedal withdrawal reflex. Animals were monitored throughout the anesthetic period and during the recovery. Venous blood samples were collected from a central venous catheter before anesthesia and at 30 minutes for the 30-minute infusion and at 30, 60, 90, 120 and 150 minutes for the 150-minute infusion. The ability of the cat to lift its head, crawl, stand and walk without ataxia was recorded at 5, 10, 20, 40, 60, 80, 120, 160, 180, 210 and 240 minutes after the completion of propofol administration. Data from physiological values were analyzed using either a Student's t-test (30-minute infusion) or an anova (150-minute infusion). A nonparametric Friedman test (and post-hoc Tukey's Studentized range test) was used to determine whether there were differences in the time taken to recover. Results were considered significant if p < 0.05. RESULTS: Time taken to walk without ataxia was significantly greater in T150 (148 +/- 40 minutes) compared with T1 (80 +/- 15 minutes) and T30 (74 +/- 26 minutes). (No other recovery times were significantly different). Anesthesia with propofol was accompanied by a moderate but significant respiratory depression and a decrease in PCV and total protein. CONCLUSIONS AND CLINICAL RELEVANCE: Prolonged anesthesia with propofol in healthy cats may be associated with a delayed recovery.     

A comparison of retrobulbar and two peribulbar regional anesthetic techniques in dog cadavers

Objective

To compare injectate distribution and likelihood of regional anesthesia to the orbit following retrobulbar (RB) or peribulbar (PB) injections in dog cadavers.