Changes in colloid osmotic pressure as a function of anesthesia and surgery in the presence and absence of isotonic fluid administration in dogs

Objective  To determine how a combination of anesthetic drugs; including pre-medication, induction agents and inhalational agents; affect colloid osmotic pressure (COP) in the presence and absence of isotonic fluid administration. Secondarily, to determine if changes in total plasma protein (TPP) correlate with COP in anesthetized patients.
Study Design  Prospective, randomized clinical study.
Animals  Ten female dogs, 4 months to 4 years of age and >8 kg undergoing elective ovariohysterectomy.
Methods  All dogs were anesthetized in a similar fashion. After induction, five dogs received lactated ringer's solution (LRS) at 10 mL kg⁻¹ hour⁻¹ and five dogs received no fluid therapy during anesthesia. Blood samples were collected prior to pre-medication, prior to induction, immediately post-induction/prior to the inhalational agent, 30 minutes post-induction, at the time of recovery and 45 minutes post-discontinuation of inhalant. TPP and COP were measured from each sample.
Results  Administration of fluids resulted in a decrease in COP and TPP over time that did not return to baseline by 45 minutes after recovery. Anesthesia without the administration of fluids also resulted in a significant decrease in COP over time, that was rebounding by recovery (but still significantly less than baseline). TPP had variable correlation with COP at different time points with or without fluid administration.
Conclusions and clinical relevance  Anesthetic drugs alter COP similarly in the presence and absence of isotonic fluids. These changes in COP did not have a simple relationship to TPP and so the latter could not be used to predict COP in this patient population.     

Binding characteristics of ivermectin in plasma from collie dogs

Two types of experiments were performed in an effort to demonstrate a role for plasma proteins in determining the amount of ivermectin available for transport across the blood-brain barrier of collie dogs sensitive to the effects of the compound. The solubility of ivermectin in plasma from non-sensitive and sensitive collies was measured and found to be identical at 100 g/ml. An assay for measuring the low affinity binding interaction of ivermectin with plasma components was developed. The amount of ivermectin bound per unit of plasma was the same for samples from sensitive and non-sensitive dogs. Dog serum albumin and the high density lipoprotein portion of the plasma were both capable of binding ivermectin. No differences in the binding characteristics of ivermectin in plasma from ivermectin sensitive and non-sensitive collies were found.     

Comparison of refractometer and biuret methods for total protein measurement in body cavity fluids

Abstract: Most hand-held medical refractometers have internal scales that limit protein measurement to results ≥ 2.5 g/dL. Tables for conversion of refraction (r) to protein concentration for values as low as 0.1 g/dL were published in the 1960s, but their accuracy for use on body fluids has not been established. The purpose of this study was to assess the reliability of body cavity fluid protein determination by refractometry. We compared the protein concentration of 25 body cavity fluids as determined by 2 Goldberg type hand-held refractometers with results obtained by the biuret method. Published charts converting refraction (r) to protein concentration were used to determine protein concentration in samples with protein <2.5 g/dL. Higher protein values were read directly from the instruments. The range of comparison was limited to ≥ 0.6 g/dL, the lowest concentration of the biuret method's standard curve. Twenty-one peritoneal fluid, 2 pleural fluid and 2 pericardial fluid samples from 16 horses, 5 cattle, 3 dogs, 2 llamas and 1 cat were tested. The results obtained by the two refractometers were closely and linearly related to biuret results (P<.001), with slopes by linear regression analysis close to 1, and correlation coefficients >0.977. Based on this study, the range for quantification of body cavity fluid protein concentration by refractometry can be extended below 2.5 g/dL, allowing for quantitative assessment of most clinical samples.     

Serum C-reactive protein concentration as an indicator of remission status in dogs with multicentric lymphoma

BACKGROUND: The acute-phase protein C-reactive protein (CRP) is used as a diagnostic and prognostic marker in humans with various neoplasias, including non-Hodgkin's lymphoma. OBJECTIVE: To evaluate if CRP could be used to detect different remission states in dogs with lymphoma. ANIMALS: Twenty-two dogs with untreated multicentric lymphoma. METHODS: Prospective observational study. Blood samples were collected at the time of diagnosis, before each chemotherapy session, and at follow-up visits, resulting in 287 serum samples. RESULTS: Before therapy, a statistically significant majority of the dogs (P = .0019) had CRP concentrations above the reference range (68%, 15/22). After achieving complete remission 90% (18/20) of the dogs had CRP concentrations within the reference range, and the difference in values before and after treatment was statistically significant (P < .001). CRP concentrations of dogs in complete remission (median, 1.91; range, 0.2-103) were significantly different (P = .031) from those of dogs with partial remission (median, 2.48; range, 0-89), stable disease (median, 1.77; range, 1.03-42.65), or progressive disease (median, 8.7; range, 0-82.5). There was profound variation of CRP measurements within each dog. CONCLUSIONS: CRP is useful in determining complete remission status after treatment with cytotoxic drugs. However, the individual variation between dogs means CRP concentration is not sufficiently different in other remission states to permit its use in monitoring progression of the disease. Greater reliability in determining remission status might be achieved by combining CRP concentration with other serum markers.     

Total antioxidant capacity and protein peroxidation intensity in seminal plasma of infertile and fertile dogs

The aim of this study was to evaluate the total antioxidant capacity and protein peroxidation intensity in seminal plasma of infertile and fertile dogs. The study was conducted on 10 infertile and 10 fertile dogs of various breeds. Infertility was defined as conception failure at least three matings with different bitches. Semen was collected by manual manipulation. The sperm concentration and motility parameters were evaluated using CASA Hamilton Thorne, Vers. IVOS 12.3. The morphology of spermatozoa and the percentage of live and dead sperm cells were assessed microscopically, total antioxidant capacity and the content of SH‐groups in seminal plasma were determined spectrophotometrically, the contents of protein peroxidation markers in seminal plasma, bityrosine and formylokinurenine, were determined using spectrofluorimetric methods. Sperm concentration and total sperm count were significantly (p < 0.05) lower in infertile dogs than in fertile dogs (99.92 ± 3 0.05 × 10⁶/ml vs. 282.07 ± 48.27 × 10⁶/ml; 214.19 ± 114.74 × 10⁶ vs. 747.57 ± 210.94 × 10⁶, respectively). The percentage of spermatozoa with normal morphology and the most determined motility parameters differed significantly (p < 0.05) between both groups. The mean values of total antioxidant capacity in the seminal plasma were significantly (p < 0.05) lower (19.95 ± 20.94 vs. 25.66 ± 23.18 µmol/g protein), whereas the mean contents of bityrosine and formylokinurenine in seminal plasma were significantly (p < 0.05) higher in infertile dogs than in fertile dogs (3.71 ± 4.83 µg/mg protein vs. 1.55 ± 2.00 µg/mg protein and 0.37 ± 0.45 µg/mg protein vs. 0.14 ± 0.08 µg/mg protein, respectively). In conclusion, the obtained results suggest that the poor semen quality and infertility in dogs could be associated with lowered total antioxidant capacity and increased protein peroxidation in seminal plasma as a consequence of oxidative stress.     

Analytical performance and method comparison of a quantitative point-of-care immunoassay for measurement of bile acids in cats and dogs

Point-of-care analyzers (POCAs) for quantitative assessment of bile acids (BAs) are scarce in veterinary medicine. We evaluated the Fuji Dri-Chem Immuno AU10V analyzer and v-BA test kit (Fujifilm) for detection of feline and canine total serum BA concentration. Results were compared with a 5th-generation assay as reference method and a 3rd-generation assay, both run on a bench-top analyzer. Analytical performance was assessed at 3 different concentration ranges, and with interferences. For method comparison, samples of 60 healthy and diseased cats and 64 dogs were included. Linearity was demonstrated for a BA concentration up to 130 µmol/L in cats (r = 0.99) and 110 µmol/L in dogs (r = 0.99). The analyzer showed high precision near the lower limit of quantification of 2 µmol/L reported by the manufacturer. Intra- and inter-assay coefficients of variation were < 5% for both species and all concentrations. Interferences were observed for bilirubin (800 mg/L) and lipid (4 g/L). There was excellent correlation with the reference method for feline (r_s = 0.98) and canine samples (r_s = 0.97), with proportional biases of 6.7% and −1.3%, respectively. However, a large bias (44.1%) was noted when the POCA was compared to the 3rd-generation assay. Total observed error was less than total allowable error at the 3 concentrations. The POCA reliably detected feline and canine BA in clinically relevant concentrations.     

Effects of pre‐operative administration of medetomidine on plasma insulin and glucose concentrations in healthy dogs and dogs with insulinoma

ObjectiveTo investigate the effect of medetomidine on plasma glucose and insulin concentrations in dogs with insulinoma and in healthy dogs undergoing anesthesia and surgery.AnimalsTwenty–five dogs with insulinoma and 26 healthy dogs.MethodsIn dogs with insulinoma, medetomidine (5 μg kg^?1) was randomly included (n = 12) or omitted (n = 13) from the pre–anesthetic medication protocol, which typically contained an opioid and an anticholinergic. Healthy dogs received medetomidine (5 μg kg^?1; n = 13) or acepromazine (0.04 mg kg^?1; n = 13) plus an opioid (morphine 0.5 mg kg^?1) and an anticholinergic (atropine 0.04 mg kg^?1) as pre–anesthetic medications. Pre–anesthetic medications were given intramuscularly. Plasma glucose and insulin concentrations were measured before (sample 1) and 30 minutes after pre–anesthetic medication (sample 2), and at the end of surgery in dogs with insulinoma or at 2 hours of anesthesia in healthy dogs (sample 3). Glucose requirement to maintain intra–operative normoglycemia in dogs with insulinoma was quantified and compared. Data were analyzed with anova and Bonferroni post–test, t–tests or chi–square tests as appropriate with p < 0.05 considered significant. Data are shown as mean ± SD.ResultsMedetomidine significantly decreased plasma insulin concentrations and increased plasma glucose concentrations in healthy dogs and those with insulinoma. These variables did not change significantly in the dogs not receiving medetomidine. In the dogs with insulinoma, intra–operative glucose administration rate was significantly less in the animals that received medetomidine compared to those that did not.ConclusionsPre–anesthetic administration of medetomidine significantly suppressed insulin secretion and increased plasma glucose concentration in dogs with insulinoma and in healthy dogs undergoing anesthesia and surgery.Clinical relevanceThese findings support the judicious use of medetomidine at low doses as an adjunct to the anesthetic management of dogs with insulinoma.     

Extracellular cyclic adenosine monophosphate‐dependent protein kinase A autoantibody and C‐reactive protein as serum biomarkers for diagnosis of cancer in dogs

Protein kinase A, a cyclic adenosine monophosphate (AMP)‐dependent enzyme, normally exists within mammalian cells; however, in cancer cells, it can leak out and be found in the serum. Extracellular cyclic AMP‐dependent protein kinase A (ECPKA) has been determined to increase in the serum of cancer‐bearing dogs. However, there have been no reports in the veterinary literature on serum ECPKA autoantibody (ECPKA‐Ab) expression in dogs with cancer. The aim of this study was to evaluate ECPKA‐Ab and C‐reactive protein (CRP) as serum biomarkers for cancer in dogs. ECPKA‐Ab and CRP levels were detected by an enzyme‐linked immunosorbent assay in serum samples from dogs with malignant tumours (n = 167), benign tumours (n = 42), or non‐tumour disease (n = 155) and from healthy control dogs (n = 123). ECPKA‐Ab and CRP levels were significantly higher in the dogs with malignant tumours than in those with benign tumours or non‐tumour diseases, as well as in the healthy controls (P < 0.001, Kruskal‐Wallis test). There was a significant positive correlation between the neoplastic index, which was developed using ECPKA‐Ab and CRP levels, and the presence of cancer in dogs (P < 0.001); the area under the receiver‐operating characteristic curve was estimated to be >0.85 (P < 0.001). In conclusion, ECPKA‐Ab is a potential serum biomarker for a broad spectrum of cancers. Combined measurement of CRP and ECPKA‐Ab levels in serum improves the sensitivity and accuracy of a diagnosis of cancer in dogs.     

RESEARCH PAPER: Comparison between two methods for cardiac output measurement in propofol‐anesthetized dogs: thermodilution and Doppler

ObjectiveTo compare cardiac output (CO) measured by Doppler echocardiography and thermodilution techniques in spontaneously breathing dogs during continuous infusion of propofol. To do so, CO was obtained using the thermodilution method (CO_TD) and Doppler evaluation of pulmonary flow (CO_DP) and aortic flow (CO_DA).Study designProspective cohort study.AnimalsEight adult dogs weighing 8.3 ± 2.0 kg.MethodsPropofol was used for induction (7.5 ± 1.9 mg kg^?1 IV) followed by a continuous rate infusion at 0.7 mg kg^?1 minute^?1. The animals were positioned in left lateral recumbency on an echocardiography table that allowed for positioning of the transducer at the 3rd and 5th intercostal spaces of the left hemithorax for Doppler evaluation of pulmonary and aortic valves, respectively. CO_DP and CO_DA were calculated from pulmonary and aortic velocity spectra, respectively. A pulmonary artery catheter was inserted via the jugular vein and positioned inside the lumen of the pulmonary artery in order to evaluate CO_TD. The first measurement of CO_TD, CO_DP and CO_DA was performed 30 minutes after beginning continuous infusion (T0) and then at 15‐minute intervals (T15, T30, T45 and T60). Numeric data were submitted to two‐way anova for repeated measurements, Pearson’s correlation coefficient and Bland &; Altman analysis. Data are presented as mean ± SD.ResultsAt T0, CO_TD was lower than CO_DA. CO_DA was higher than CO_TD and CO_DP at T30, T45 and T60. The difference between the CO_TD and CO_DP, when all data were included, was ?0.04 ± 0.22 L minute^?1 and Pearson’s correlation coefficient (r) was 0.86. The difference between the CO_TD and CO_DA was ?0.87 ± 0.54 L minute^?1 and r = 0.69. For CO_TD and CO_DP, the difference was ?0.82 ± 0.59 L minute^?1 and r = 0.61.ConclusionDoppler evaluation of pulmonary flow was a clinically acceptable method for assessing the CO in propofol‐anesthetized dogs.     

Anti‐diabetic effect of camel milk in alloxan‐induced diabetic dogs: a dose–response experiment

This study was conducted to evaluate the effect of camel milk in alloxan‐induced diabetic dogs and to follow this effect at three doses of milk. Firstly, three groups of dogs were used: two groups composed each of four diabetic dogs and receiving raw camel milk (treatment 1) or cow milk (treatment 2), and four healthy dogs getting raw camel milk (treatment 3) were used as control. Each animal was treated with 500 ml of milk daily. Secondly, we compared the effects of three amounts of camel milk: 100 ml, 250 ml and 500 ml to treat the diabetic dogs. After week 3, the dogs treated with camel milk showed a statistically significant decrease in blood glucose (from 10.88 ± 0.55 to 6.22 ± 0.5 mmol/l) and total protein concentrations (from 78.16 ± 2.61 g/l to 63.63 ± 4.43 g/l). For cholesterol levels, there was a decrease from week 2 (from 6.17 ± 0.5 mmol/l to 4.79 ± 0.5 mmol/l). There were no significant difference in blood glucose, cholesterol or total protein concentrations in dogs drinking 250 and 500 ml of camel milk. The dogs treated with 100 ml of camel milk did not show any significant decrease in blood glucose levels, and cholesterol and total protein concentrations. The investigation was not limited to the improvement in glycemic balance, lipids and proteins control in diabetic dogs getting camel milk, but we also noted a stability of this state after the dogs stopped to drink milk. This effect depended on the quantity of camel milk used to treat diabetic dogs.     

Romifidine and low doses of tiletamine‐zolazepam in dogs

ObjectiveTo evaluate clinical effects of romifidine and low doses of tiletamine‐zolazepam (TZ) in dogs.Study designRandomized “blinded” cross‐over study.AnimalsSix healthy beagle dogs (two males, four females).MethodsIn separate preliminary experiments dogs received intravenous (IV) tiletamine‐zolazepam (TZ) at 1 and 2 mg kg^?1. For the main trial, dogs received romifidine (R) followed 5 minutes later by IV at six dose regimens: R40TZ1, R60TZ1, R80TZ1 (Romifidine at 40, 60, 80 μg kg^?1 and TZ at 1 mg kg^?1), R40TZ2, R60TZ2 and R80TZ2 (Romifidine at 40, 60, 80 μg kg^?1 and TZ at 2 mg kg^?1). Dogs underwent endotracheal intubation, but breathed room air. Cardiorespiratory variables were measured and arterial blood analyzed. Quality of sedation, duration of anaesthesia and time to recovery (TR) were recorded. Data were analysed by anova or Friedman test as relevant.ResultsEndotracheal intubation was possible with all romifidine/TZ combinations but not with TZ alone. Mean times (minutes) from TZ injection to return of pedal reflex were 1–3 minutes for TZ alone, and 9–17 minutes for romifidine combinations. In the main trial (romifidine combinations) mean time (minutes) to standing increased with increasing dosage (R40TZ1 13; R80TZ2 32). Five minutes after TZ administration, when compared with baseline arterial blood pressures and arterial carbon dioxide had increased, and respiratory rate, pH and arterial oxygen tensions decreased, these changes becoming statistically significant with the higher dose rates. One dog in R60TZ2 and three dogs in R80TZ2 became hypoxaemic.Conclusions and clinical relevanceRomifidine improves the quality and lengthens the duration of anaesthesia induced by TZ. The combination provides a suitable protocol for induction of or short‐term anaesthesia in healthy dogs. However, the higher doses cause cardiovascular stimulation and respiratory depression, and precautions should be taken accordingly.     

C-reactive protein as an indicator of inflammatory responses to experimentally induced cystitis in dogs

The aim of this study was to demonstrate and assess C-reactive protein (CRP) changes in dogs with induced bacterial cystitis with or without antibiotics. We also evaluated availability of CRP levels to serve as an indicator for monitoring or diagnosing bacterial cystitis. Serial CRP concentrations in dogs with induced bacterial cystitis were higher than those of controls (p < 0.001). CRP concentrations peaked on day 7 and gradually decreased thereafter. In the treatment group, CRP concentrations decreased after medication compared to the untreated group (p = 0.032). CRP levels had a linear correlation with urine white blood cell counts among all groups (r = 0.837, p < 0.001, n = 140). Compared to the negative urine culture group, dogs with positive urine culture results had higher CRP concentrations (median 43.8 mg/L vs. 5.9 mg/L; p < 0.001). Area under the receiver operating characteristic curve was 0.955; when cut-off value was 12.2 mg/L, CRP measurements were found to have a sensitivity of 92.3% and specificity of 86.4%. This result indicates that rapid increases of CRP occurred after inducing bacterial cystitis and CRP may be a useful indicator for monitoring or diagnosing canine bacterial cystitis together with sediment urinalysis and urine bacterial culture.