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61.
Sudden blindness associated with protothecosis in a dog   总被引:1,自引:0,他引:1  
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62.
A survey of veterinarians' use of antibacterial drugs was conducted by distributing a questionnaire to Australian practitioners. Respondents were asked to indicate their general patterns of use of various systemic antibacterial drugs and drug combinations in dogs and their approach to certain specified clinical disorders. Overall, antibacterials of the p-lactam type (penicillins and cephalosporins) were most commonly used. Other antibacterials with substantial use were doxycycline, sulphonamide-trimethoprim, metronidazole, fluoroquinolones and clindamycin. Drug selection for different disorders was generally appropriate when compared with recommendations in recent texts, although inappropriate use was evident in some circumstances.  相似文献   
63.
Alfentanil (50 μg/kg) was administered intravenously, over 1 minute, to 6 healthy cats. Blood samples were collected from a preplaced arterial catheter at 0.625, 1.25, 2.5, 5, 10, 15, 20, 30, 45, 60, 90, 120, 180, 240, 360, and 480 minutes after the end of the alfentanil injection. A radio-immunoassay technique was used to measure alfentanil concentrations in plasma obtained from these samples. Arterial blood pressure was measured at 0.625, 1.25, 2.5, 5, 10, 15, 20, and 30 minutes and pH and blood gas measurements were carried out at 5, 10 and 30 minutes after the alfentanil. Analgesia, tested by placing a clamp on the base of the tail for 5 seconds, was assessed at each blood sampling time until analgesia was absent. The cats were observed for behavioural changes at each sample time. Alfentanil caused a transient increase in blood pressure and respiratory and metabolic acidosis. Following alfentanil all cats became excited and showed pupillary dilation. Analgesia was present for 21.7 ± 14 minutes. The plasma concentration-time data for 5 cats were best described by a 3 compartment open model with the curve fitting the equation: Cto= 162.6e-0.2062t+ 60.le-0.041t+ 13.2e-0.0062t The harmonic means for the half lives of the rapid distribution, the slow distribution and the elimination phases were 4.12, 18.8, 119.2 minutes respectively.  相似文献   
64.
Cardiopulmonary effects of propofol were studied in hypovolemic dogs from completion of, until 1 hour after administration. Hypovolemia was induced by withdrawal of blood from dogs until mean arterial pressure of 60 mm of Hg was achieved. After stabilization at this pressure for 1 hour, 6 mg of propofol/kg of body weight was administered IV to 7 dogs, and cardiopulmonary effects were measured. After blood withdrawal and prior to propofol administration, oxygen utilization ratio increased, whereas mean arterial pressure, mean pulmonary arterial pressure, central venous pressure, pulmonary capillary wedge pressure, cardiac index, oxygen delivery, mixed venous oxygen tension, and mixed venous oxygen content decreased from baseline. Three minutes after propofol administration, mean pulmonary arterial pressure, pulmonary vascular resistance, oxygen utilization ratio, venous admixture, and arterial and mixed venous carbon dioxide tensions increased, whereas mean arterial pressure, arterial oxygen tension, mixed venous oxygen content, arterial and mixed venous pH decreased from values measured prior to propofol administration. Fifteen minutes after propofol administration, mixed venous carbon dioxide tension was still increased; however by 30 minutes after propofol administration, all measurements had returned to values similar to those measured prior to propofol administration.  相似文献   
65.
66.
OBJECTIVE: To characterize the shape of the relationship between plasma ketamine concentration and minimum alveolar concentration (MAC) of isoflurane in dogs. STUDY DESIGN: Retrospective analysis of previous data. ANIMALS: Four healthy adult dogs. METHODS: The MAC of isoflurane was determined at five to six different plasma ketamine concentrations. Arterial blood samples were collected at the time of MAC determination for measurement of plasma ketamine concentration. Plasma concentration/effect data from each dog were fitted to a sigmoid inhibitory maximum effect model in which MAC(c)= MAC(0) - (MAC(0)-MAC(min)) x C(gamma)/EC(50)(gamma)+C(gamma), where C is the plasma ketamine concentration, MAC(c) is the MAC of isoflurane at plasma ketamine concentration C, MAC(0) is the MAC of isoflurane without ketamine, MAC(min) is the lowest MAC predicted during ketamine administration, EC(50) is the plasma ketamine concentration producing 50% of the maximal MAC reduction, and gamma is a sigmoidicity factor. Nonlinear regression was used to estimate MAC(min), EC(50), and gamma. RESULTS: Mean +/- SEM MAC(min), EC(50) and gamma were estimated to be 0.11 +/- 0.01%, 2945 +/- 710 ng mL(-1) and 3.01 +/- 0.84, respectively. Mean +/- SEM maximal MAC reduction predicted by the model was 92.20 +/- 1.05%. CONCLUSIONS: The relationship between plasma ketamine concentration and its effect on isoflurane MAC has a classical sigmoid shape. Maximal MAC reduction predicted by the model is less than 100%, implying that high plasma ketamine concentrations may not totally abolish gross purposeful movement in response to noxious stimulation in the absence of inhalant anesthetics. CLINICAL RELEVANCE: The parameter estimates reported in this study will allow clinicians to predict the expected isoflurane MAC reduction from various plasma ketamine concentrations in an average dog.  相似文献   
67.
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.  相似文献   
68.
69.
Abstract

AIM: To examine the effect of setting a maximum milking time, from peak lactation until drying-off, on production, duration of milking, and udder health of dairy cows.

METHODS: Forty cows were assigned in twin-pairs to be either milked until cups were removed at a milk flow-rate threshold of 0.35 kg/minute (Control), or until cups were removed at a milk flow-rate threshold of 0.35 kg/minute, or maximum time, whichever came first (MaxT). The maximum time was set by determining the milking time of the 70th percentile cow when ranked from fastest to slowest, irrespective of yield. The milking routine was typical of that practised on dairy farms in New Zealand, and involved no pre-milking preparation. The study began at peak lactation (68 (SD 7) days in milk; DIM) and continued for 26 weeks. Duration of milking and milk yield were measured for each milking. Composition of milk was determined from weekly herd tests, and milk quality from fortnightly somatic cell counts (SCC). Completeness of milking and teat condition were assessed during the study. The bacterial status of quarter milk samples was determined at the beginning and end of the study, and all treated cases of clinical mastitis recorded. ANOVA was used to examine the effect of treatment group on variables of interest.

RESULTS: Total milk, fat and protein yields during the study period did not differ between treatments. On average, 30.3% of the morning and 27.6% of the afternoon milkings of MaxT cows reached the maximum time at which cups were removed, and were therefore shortened. While the average milking time of the slowest-milking cow was longer for the Control compared with MaxT group in Weeks 1–18, the average milking time did not differ between treatments. There was no difference in overall SCC, and the incidence of clinical mastitis, or the percentage of infected quarters at drying-off, was similar for the MaxT and Control cows.

CONCLUSION: The results show that setting a maximum milking time can reduce the milking time of slower-milking cows in a herd without compromising overall herd production and udder health.

CLINICAL RELEVANCE: Although the numbers of cows in the study were small there was no evidence of a major increase in SCC, or subclinical or clinical mastitis when a maximum milking time was set for slower-milking cows.  相似文献   
70.
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.  相似文献   
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