Evaluation of transformation growth factor beta1, interleukin-10, and interferon-gamma in male symptomatic and asymptomatic dogs naturally infected by Leishmania (Leishmania) chagasi

The aims of this study were to evaluate the immunomodulatory role of TGF-β₁, IL-10, and INF-γ in spleen and liver extracts and supernatant cultures of white spleen cells from male symptomatic and asymptomatic dogs, naturally infected by Leishmania (Leishmania) chagasi. Thirty dogs from Araçatuba, São Paulo, Brazil, an endemic leishmaniosis area, were selected by positive ELISA serological reaction for Leishmania sp. and divided into two groups: asymptomatic (n = 15) and symptomatic (n = 15) consisting of animals with at least three characteristic signs (fever, dermatitis, lymphoadenopathy, onychogryphosis, weight loss, cachexia, locomotion problems, conjunctivitis, epistaxis, hepatosplenomegaly, edema, and apathy). After euthanasia, spleen and liver fragments were collected for ex vivo quantification of TGF-β₁, IL-10, and INF-γ. Naturally active in vitro produced TGF-β₁ was also evaluated in spleen cell culture supernatant. Spleen and liver extract of asymptomatic dogs had higher mean TGF-β₁ levels than symptomatic dogs. High concentrations of IL-10 were found in spleen, and mainly in liver extract of both groups. Higher INF-γ concentrations were found in spleen extracts of symptomatic dogs, and in liver extracts of asymptomatic dogs. Extract of this cytokine was lower in spleen extract. Although INF-γ is being produced in canine infection, mean levels of TGF-β₁ and IL-10 from spleen and liver extracts were quantitatively much higher; suggesting that immune response in both asymptomatic and symptomatic dogs was predominantly type Th2.     

Evaluation of serological cross-reactivity between canine visceral leishmaniasis and natural infection by Trypanosoma caninum

In order to evaluate if the presence of Trypanosoma caninum can lead to a confuse diagnosis of canine visceral leishmaniasis (CVL), we investigated the serological status of dogs infected by T. caninum and assessed the serological cross-reactivity with CVL. A set of 117 serum samples from dogs infected by T. caninum, Leishmania chagasi and not infected dogs (n = 39 in each group) was tested using commercial kits – indirect immunofluorescence (IFI-LVC), ELISA (EIE-LVC) and immunochromatographic test (DPP) – and in house tests with T. caninum (IIF-Tc and ELISA-Tc) and L. chagasi antigens (IIF-Lc and ELISA-Lc). IIF-Tc and ELISA-Tc presented sensitivity of 64.1% and 94.9% and specificity of 23.1% and 35.9%, respectively. The sensitivity of the IFI-LVC, EIE-LVC and DPP tests was 100% and the specificity was 70.5%, 68% and 97.5% respectively. The concordance between the tests was considered as satisfactory. The specificities of IFI-LVC, EIE-LVC and DPP were higher when the group Tc was excluded, with significant values for IFI-LVC (χ² = 4.36, P-value = 0.036), thus suggesting that the infection by T. caninum can confuse the diagnosis of CVL.     

Influence of age on bronchoscopic findings in healthy beagle dogs

The aims of this study were to evaluate the effect of age on bronchoscopic features and bronchoalveolar lavage fluid (BALF) cellularity in dogs. Thirty healthy beagle dogs from three age groups were included: young dogs (10 months to 4.5 years of age; n = 8), middle-aged dogs (5–8 years old; n = 13) and older dogs (>8 years; n = 9). Haematology, thoracic radiography, bronchoscopy and bronchoalveolar lavage were performed; bronchoscopic findings were scored and BALF total and differential cell counts were determined. The total bronchoscopic score was higher in older dogs; these dogs had more irregular bronchial mucosa, more prominent mucosal vessels and bronchiectasis. Younger dogs had a higher percentage of neutrophils in BALF compared with middle-aged and old dogs and a higher percentage of lymphocytes in BALF compared with middle-aged dogs. The results show that age has an effect on bronchoscopic features of airways and the composition of BALF in the dog.     

Identification of Babesia species infecting dogs using reverse line blot hybridization for six canine piroplasms,and evaluation of co-infection by other vector-borne pathogens

Canine infection by vector-borne hemoparasites is frequent in tropical and sub-tropical areas where exposure to hematophageous ectoparasites is intensive. A reverse line blot (RLB) assay was designed to improve the simultaneous detection of all named canine piroplasm species combined with other vector-borne pathogens of dogs including Ehrlichia canis, Hepatozoon canis and Leishmania infantum common in the Mediterranean basin. Blood samples of 110 dogs from Spain (n = 21), Portugal (n = 14) and Israel (n = 75) were analyzed. The study evaluated 2 groups of dogs, 49 dogs with piroplasm infection detected by blood smear microscopy from Portugal, Spain and Israel, and 61 dogs surveyed from rural areas in Israel, for which infection status with vector-borne pathogens was unknown. Among the dogs previously diagnosed with piroplasmosis, infection with Babesia canis, Babesia vogeli, Babesia gibsoni and Theileria annae was detected in the Iberian dogs while only B. vogeli was found in Israeli dogs. These differences are attributed to the absence of tick vectors for some piroplasm species such as Dermacentor reticulatus in Israel. Eleven (79%) of the Babesia-positive dogs from Portugal were co-infected with other pathogens including L. infantum, H. canis and E. canis. Eight of 61 (13%) rural Israeli dogs were co-infected with two or more pathogens including B. vogeli, L. infantum, E. canis, and H. canis. Triple infections were demonstrated in 2 dogs. The RLB detection limit for Babesia was 50-fold lower than that of PCR. This study presents a RLB to simultaneously detect and separate the major vector-borne dog pathogens in southern Europe and the Middle East.     

An unmatched case controlled study of clinicopathologic abnormalities in dogs with Bartonella infection

We compared clinicopathologic findings in dogs with Bartonella infection to Bartonella spp. negative dogs suspected of a vector-borne disease. Cases (n = 47) and controls (n = 93) were selected on the basis of positive or negative enrichment culture PCR results, respectively. Signalment, clinicopathologic findings and treatments were extracted from medical records. DNA sequencing identified Bartonella henselae (n = 28, 59.6%), Bartonella vinsonii subsp. berkhoffii (n = 20, 42.6%), Bartonella koehlerae (n = 3, 6.4%), Bartonella volans-like (n = 3, 6.4%) and Bartonella bovis (n = 1, 2.1%). There were no significant differences in age, breed, size, sex or neuter status between cases and controls. Dogs infected with Bartonella sp. often had a history of weight loss [OR = 2.82; 95% CI: 1.08–7.56] and were hypoglobulinemic [OR = 4.26; 95% CI: 1.31–14.41]. With the exception of weight loss and hypoglobulinemia, clinicopathologic abnormalities in Bartonella-infected dogs in this study were similar to dogs suspected of other vector-borne infections.     

Quadricuspid aortic valve and associated abnormalities in the dog: Report of six cases

ObjectivesTo describe the clinical and echocardiographic findings in dogs with quadricuspid aortic valve (QAV).BackgroundQAV is a rare canine congenital heart disease which has been reported only three times in the young dog.Animals, materials and methodsSix dogs (0.3- to 13-year-old) with QAV diagnosed by two-dimensional echocardiography were retrospectively evaluated. Medical records, echocardiograms, and follow-ups were reviewed.ResultsAccording to aortic cusp morphology, QAV was classified as type A (n = 1), type B (n = 4) or type C (n = 1). QAV was associated with at least one other heart disease in all of the dogs including, ventricular septal defect (n = 1), enlarged left coronary ostium (n = 4), degenerative mitral valve disease (MVD, n = 1) and patent ductus arteriosus (PDA, n = 3). Mild to moderate aortic regurgitation was also detected in all dogs by continuous-wave and color-flow Doppler echocardiography. QAV was diagnosed in four asymptomatic dogs referred for evaluation of a heart murmur. The remaining two dogs had QAV and PDA with evidence of mild exercise intolerance and moderately retarded growth. The PDA was surgically corrected in both dogs and at the time of writing, 1–2.5 years after the initial diagnosis, none of the six animals shows evidence of clinical signs.ConclusionQAV is a cause of aortic insufficiency. It may incidentally be found by two-dimensional echocardiography in dogs of various ages in association with other congenital or acquired cardiac abnormalities.     

Novel markers of inflammatory response and hepatic dysfunction in canine leishmaniasis

Dogs are the main host of Leishmania infantum, and the clinical presentation may range from asymptomatic to systemic manifestations. The immune mechanisms in infected, but clinically healthy dogs, prevails Th1 response mediated by cytokines. In this sense, adenosine deaminase (ADA) and butyrylcholinesterase (BChE) are considered as key enzymes in several physiological processes, including the modulation of inflammatory process. Considering the variable immune response against Leishmania and the known participation of ADA and BChE, the aim of this study was to assess the relation between these two enzymes with the inflammatory response as well as hepatic function in dogs naturally infected with L. infantum. For this purpose, the activity of ADA and BChE was assessed in sera of 24 dogs naturally infected with L. infantum, plus 17 healthy dogs. The naturally infected dogs had clinical signs compatible with leishmaniasis and sera activities of ADA (P < 0.01) and BChE (P < 0.05) decreased, when compared to the healthy group. The reduction of ADA activity probably represented an effect on inflammatory response, especially due to the decreased hydrolysis of extracellular adenosine, might in order to protect against tissue damage and, also, setting a down-regulation on pro-inflammatory cytokines. BChE enzyme had no effect on modulating the immune response in leishmaniasis, but it decreased, a fact may related to deficiency of synthesis in the liver. Therefore, ADA and BChE activities reduced probably in order to protect against extra tissue damage and due failure in synthesis, respectively.     

Computed tomographic morphology and clinical features of extrahepatic portosystemic shunts in 172 dogs in Japan

Canine extrahepatic congenital portosystemic shunts (EH-cPSS) are classified into several anatomical types, depending on the origin and termination of the shunt vessel. The aim of this retrospective study was to determine the proportion and clinical features of each anatomical shunt type in a population of dogs presented to a veterinary teaching hospital in Japan. Dogs diagnosed with EH-cPSS using computed tomographic (CT) portography were included (n = 172) and shunts were classified based on previous reports. Clinical data were collected from case records and analysed statistically. The most common anatomical type was the spleno-phrenic shunt (n = 64), followed by the spleno-azygos (n = 38), right gastric-caval (n = 29), spleno-caval (n = 21), right gastric-caval with caudal loop (n = 9), right gastric-phrenic (n = 6), colono-caval (n = 3), spleno-phrenic and azygos (n = 1), and porto-caval (n = 1) shunts. Spleno-phrenic and spleno-azygos shunts were diagnosed more frequently in older dogs than right gastric-caval and spleno-caval shunts (P < 0.05). The portal vein/aortic (PV/Ao) ratio was significantly larger in dogs with spleno-phrenic shunts than in dogs with spleno-azygos, right gastric-caval or spleno-caval shunts (P < 0.05). The PV/Ao ratio was significantly larger in dogs with spleno-azygos shunts than in dogs with right gastric-caval shunts. Dogs with spleno-phrenic shunts had significantly lower serum alkaline phosphatase activities than those with right gastric-caval or spleno-caval shunts. Dogs with spleno-phrenic shunts had significantly lower fasting ammonia concentrations than those with spleno-caval shunts.     

Effect of azotemia on serum N-terminal proBNP concentration in dogs with normal cardiac function: A pilot study

ObjectivesTo evaluate amino-terminal pro-B type natriuretic peptide (NT-proBNP) concentration in dogs with renal dysfunction and normal cardiac structure and function.AnimalsEight dogs with renal disease, 23 healthy control dogs.MethodsSerum NT-proBNP concentration was measured in healthy dogs and dogs with renal disease using an ELISA validated for use in dogs. Affected dogs were eligible for inclusion if renal dysfunction was diagnosed based on urinalysis and serum chemistry, and if they were free of cardiovascular disease based on physical exam, systolic blood pressure, and echocardiography.ResultsThe geometric mean serum NT-proBNP concentration was significantly higher in dogs with renal disease (617 pmol/L; 95% CI, 260–1467 pmol/L) than in healthy control dogs (261 pmol/L; 95% CI, 225–303 pmol/L; P = 0.0014). There was a modest positive correlation between NT-proBNP and BUN and creatinine. Median NT-proBNP concentration was not significantly different between groups when indexed to BUN (median NT-proBNP:BUN ratio; renal, 14.2, IQR, 3.93–17.7 vs. control, 16.3, IQR, 9.94–21.2; P = 0.29) or creatinine (median NT-proBNP:creatinine ratio; renal, 204, IQR, 72.6–448 vs. control, 227, IQR, 179–308; P = 0.67).ConclusionDogs with renal disease had significantly higher mean serum concentration of NT-proBNP than control dogs. Renal function should be considered when interpreting NT-proBNP results as concentrations may be falsely elevated in dogs with renal dysfunction and normal cardiac function. The effect of renal disease was lessened by indexing NT-proBNP to BUN or creatinine. Future studies in dogs with both renal and heart disease are warranted.     

Entamoeba infections in different populations of dogs in an endemic area of Lahore,Pakistan

Entamoeba histolytica, a protozoan parasite that affects humans and other primates all over the world. It is a common waterborne pathogen in endemic areas that have fecal oral transmission cycle. The aim of the present study was to examine the prevalence of E. histolytica and other Entamoeba species cysts in three different dog populations. Fecal samples from 600 dogs were collected and processed to detect Entamoeba cysts using the triple fecal test (light microscopy) and fecal antigens of E. histolytica were detected using a fecal antigen ELISA (TechLab E. histolytica II). Because it is impossible to differentiate E. histolytica from Entamoeba dispar and E. moshkovskii, using light microscopy we referred to all cysts morphologically consistent with E. histolytica as E. histolytica/dispar/moskovskii to reflect this uncertainty. Samples from 197 household dogs without clinical signs, 122 samples from household dogs exhibiting clinical signs of diarrhea, dysentery and vomiting and 281 stray dogs with no specific clinical signs were examined. Entamoeba histolytica-like cysts were observed in 94 (15.6%, 95% CI = ±3.88) by triple fecal test microscopy and E. histolytica antigens were demonstrated in 66 (11%, 95% CI = ±4.41) by fecal antigen ELISA in 600 fecal samples. Significant differences (P ≤ 0.05) in prevalence were found between the three populations. Twenty (10.1%, 95% CI = ±7.86) and 11 (5.6%, 95% CI = ±7.70) of 197 fecal samples from household dogs without clinical signs were positive by microscopy and by antigen ELISA, respectively. Twenty-nine (23.8%, 95% CI = ±6.58) and 23 (18.8%, 95% CI = ±7.81) of 122 the fecal samples from household dogs with clinical signs were positive by microscopy and by antigen ELISA, respectively. Forty-five (16.01%, 95% CI = ±5.62) and 32 (11.3%, 95% CI = ±6.38) of 281 fecal samples from stray dogs were positive by microscopy and by fecal antigen ELISA, respectively. Dogs from the youngest age group (6 months to 1 year) were more likely to be E. histolytica antigen positive than were dogs from the other two older age groups, with a significant difference (P ≤ 0.05) between all age groups. Statistically, no significant (P ≥ 0.05) difference of prevalence was seen in male and female dogs. The local dogs had the highest prevalence rate of E. histolytica antigens (36 of 246, 14.2%, 95% CI = ±6.32) followed by imported breeds (11 of 115, 9.5%, 95% CI = ±10.4) and crossbred (19 of 239, 8.3%, 95% CI = ±7.47), indicating a significant (P ≤ 0.05) trend of positivity between various breeds of dogs. These findings suggest that dogs may play an important role in the epidemiology of this pathogen.     

Potential novel markers to discriminate between active and latent tuberculosis infection in Chinese individuals

Latent tuberculosis infection (LTBI) constitutes the main reservoir for reactivation tuberculosis. The finding of potential biomarkers for differentiating between TB and LTBI is very necessary. In this study, the immunological characteristics and potential diagnostic utility of Rv2029c, Rv2628 and Rv1813c proteins were assessed. These three proteins stimulated PBMCs from ELISPOT-positive LTBI subjects produced higher levels of IFN-γ in comparison with TB patients and ELISPOT-negative healthy subjects (p < 0.05). BCG vaccination and non-TB respiratory disease had little influence on the immunological responses of Rv2029c and Rv2628 proteins (p > 0.05). The LTBI diagnostic performance of Rv2029c was higher than Rv2628 and Rv1813c by ROC evaluation. But Rv2628 had much higher specificity than Rv2029c in active TB patients and uninfected healthy subjects. The IgG level against Rv1813c was higher in the TB group than in LTBI and uninfected healthy subjects (p < 0.05). These results suggest that T cell response to Rv2628 and antibody against Rv1813c might be applicable as biomarkers to distinguish TB from LTBI and uninfected individuals.     

Relationship between oxidative stress and clinical–pathological aspects in dogs experimentally infected with Rangelia vitalii

The aim of this study was to evaluate lipid peroxidation, protein oxidation and activity of enzymes that are indicators of oxidative stress in Rangelia vitalii infection in dogs. Animals were divided into two groups: negative control (n = 5) and infected with R. vitalii (n = 7). After inoculation, the parasitemia was estimated daily by microscopic examination of smears. Lipid peroxidation (TBARS) and advanced oxidation protein products (AOPP); and delta-aminolevulinate dehydratase (δ-ALA-D), superoxide dismutase (SOD) and catalase (CAT) activities in blood were evaluated. The samples were collected at days 10 and 20 post-inoculation (PI). TBARS and AOPP levels were higher in the infected group in both analyzed periods (P < 0.01). The δ-ALA-D activity was reduced in blood of dogs infected with R. vitalii on days 10 and 20 PI. SOD activity was significantly increased (P < 0.01) in the blood of dogs infected with R. vitalii at days 10 and 20 PI, while CAT activity was significantly increased (P < 0.01) only at day 20 PI when compared to non-infected animals. A positive correlation was observed between the degree of parasitemia and TBARS and AOPP levels and activity of antioxidant enzymes. The δ-ALA-D activity was negatively correlated with the degree of parasitemia. Based on the increased levels of TBARS, AOPP, SOD and CAT activities, and inhibition δ-ALA-D activity, we concluded that dogs experimentally infected with R. vitalii develop a state of redox unbalance and that these changes might be involved in the pathophysiology of disease.     

Comparison of monoclonal and polyclonal antibodies for the detection of canine IgG1 and IgG2, and associations with infection outcome in Leishmania infantum naturally infected dogs

In murine models of leishmaniasis, IgG subclass expression is a proxy measure for Th1/Th2 cellular immune response bias. However, in dogs, the reservoir of zoonotic visceral leishmaniasis, no consistent association has been described between IgG subclass ratios and disease resistance. Inconsistent results may reflect lack of specificity of commonly used commercial antibodies. Our aim was to measure IgG1 and IgG2 responses to crude Leishmania antigen using commercial polyclonal antibodies for comparison with a panel of commercially unavailable monoclonal antibodies, in a cohort of 60 naturally infected dogs, and to compare associations between subclass responses and clinical or parasitological outcomes. IgG1 and IgG2, measured by both antibodies, were higher in clinically symptomatic than in asymptomatic dogs (P ≤ 0.03), reflecting general upregulation of IgG in infected dogs. Unlike the murine model, canine IgG2:IgG1 ratios were not predictive of clinical or parasitological outcomes of infection. Associations between subclass levels and positivity by bone marrow culture and PCR were not consistent when measured with different antibodies. Further research is needed to re-evaluate the specificity of commercially available IgG subclass antibodies.     

Feasibility and repeatability of thermal quantitative sensory testing in normal dogs and dogs with hind limb osteoarthritis-associated pain

The objectives of this study were to determine whether thermal quantitative sensory testing (QST) can be performed in client-owned dogs, is repeatable and whether QST differs between normal dogs and dogs with hind limb osteoarthritis (OA). This clinical, prospective, observational study used clinically normal dogs (n = 23) and dogs with OA-associated hind limb pain (n = 9). Thermal QST was performed in standing dogs using a high-powered light source delivered by a previously validated system. Dogs were tested on two occasions, 2 weeks apart. Five tests were performed on each hind limb at each time point. Repeated measures analysis of variance was used to evaluate the effects of leg, time point and OA/normal status on thermal threshold latencies (TTL). Additionally, paired t tests were used to compare the TTL of left and right limbs within groups and between time points.Thermal thresholds were successfully measured in 32 client-owned dogs without prior training. TTL were significantly different between normal and OA dogs (P = 0.012). There was no difference between limbs (P = 0.744) or time periods (P = 0.572), when analyzed by repeated measures analysis of variance, and no interactions between group and limb, visit and limb, or visit and group. In conclusion, thermal thresholds can be measured in client owned dogs with no prior training and are repeatable from week to week. Further data are required to determine if OA results in thermal hypoalgesia as measured at the distal hind limb and whether this is an indication of central sensitization.     

Weekly variability of plasma and serum NT-proBNP measurements in normal dogs

ObjectivesTo determine the weekly variability of serum and plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations in healthy dogs.Animals, materials and methodsFifty-three normal dogs were examined prospectively. Serum (n = 25) or plasma (n = 28) samples were obtained for NT-proBNP assay at one week interval for 3 consecutive weeks.ResultsMedian serum or plasma NT-proBNP concentration did not change over 3 consecutive weeks. Twenty-two of 53 dogs (42%) had at least one NT-proBNP value >500 pmol/L, including 14 dogs with at least one serum NT-proBNP concentration >500 pmol/L and 8 dogs with at least one plasma NT-proBNP concentration >500 pmol/L during the 3-week sampling period. The difference between the maximum and minimum NT-proBNP value obtained over the 3-week sampling period was <100 pmol/L in 40% of dogs, between 100 and 200 pmol/L in 40% of dogs, and >200 pmol/L in 20% of dogs. Of the 19 dogs with a value >500 pmol/L on either week 1 or 2, 11 dogs (58%) had a subsequent NT-proBNP value <500 pmol/L on either week 2 or 3.ConclusionsThere is a high degree of variability in weekly serum and plasma NT-proBNP values in healthy dogs. Individual variability should be considered when interpreting NT-proBNP results in dogs.     

Preference among 7 bait flavors delivered to domestic dogs in Arizona: Implications for oral rabies vaccination on the Navajo Nation

Less than 20% of the domestic dogs on tribal lands in the United States are vaccinated against rabies. One method to increase vaccination rates may be the distribution of oral rabies vaccines (ORVs). ONRAB^® (Artemis Technologies, Inc., Ontario, Canada) is the primary ORV used in Canada to vaccinate striped skunks and raccoons. To investigate the potential use of ONRAB^® ORV baits to vaccinate feral domestic dogs against rabies on tribal lands and beyond, we performed a flavor preference study. A total of 7 bait flavors (bacon, cheese, dog food, hazelnut, sugar-vanilla, peanut butter, and sardine) were offered in pairs to 13 domestic dogs. Each dog was offered all possible combinations of bait pairs over a period of 10 days, with each bait offered 6 times. The proportion of times each bait was consumed first by individual dogs was calculated and comparisons among dogs were conducted using the MIXED procedure in SAS (SAS Institute, Cary, NC). Pairwise comparisons between baits were performed using “contrast” statements with sugar-vanilla flavor as the default for comparison. Type 3 tests of fixed effects showed a significant treatment effect (F_6,72 = 9.74, P < 0.0001). Sugar-vanilla was selected first during 14% of the offerings and exhibited the least preference among all bait types (F_1,72 = 22.46, P < 0.0001). Dog food was selected first 56% of the time, and more frequently than all other bait types (F_1,72 = 13.09, P = 0.0005).     

Follow-up of 100 dogs with acute diarrhoea in a primary care practice

This study aimed to examine the aetiology of acute diarrhoea and the relapse rate in 100 client-owned dogs presented to a first-opinion clinic. History, physical examination, faecal testing and owner questionnaire data were collected at initial presentation (T₀) and at either the time of relapse or at a recheck performed within 3 months. All dogs received treatment according to their clinical signs. Of 96 dogs that completed the study, 37 (38.5%) relapsed during the study period, 21 (21.9%) relapsed within 3 months, and 16 others (16.6%) at 3 months to 1 year after initial examination. Dogs that had undergone a change in housing location within 1 month prior to presentation and dogs <1 year old were significantly more likely to have positive parasitological analyses (P = 0.02 and P = 0.001, respectively). Pica was a risk factor for relapse (P = 0.0002).     

A high protein high fibre diet improves weight loss in obese dogs

A newly-formulated, high protein high fibre (HPHF) diet has recently been shown to improve satiety in dogs. The current study examined its performance during weight loss in client-owned dogs with naturally-occurring obesity. Fifteen dogs were fed the HPHF diet, whilst a matched ‘control’ group of 27 dogs, received a high protein medium fibre diet (HPMF), with an equivalent caloric density. Baseline characteristics (signalment, percentage overweight, and body fat percentage) were not significantly different between groups. However, percentage weight loss was greater (median [range] 31.8% [12.0–41.2%] vs. 20.0% [5.9–45.0%], P = 0.016) and mean rate of weight loss faster (median [range] 1.0%/week [0.3–1.6%] vs. 0.7%/week [0.3–1.5%], P = 0.028) on HPHF compared with HPMF. Percentage body fat mass decrease (measured by dual-energy X-ray absorptiometry) was also greater in dogs fed the HPHF diet (median (range] 58% [32–85%) vs. 37% [15–72%), P = 0.002). Thus, a diet formulated to include high levels of both protein and fibre, improves outcome during weight loss in obese dogs.     

Effects of trilostane on the pituitary-adrenocortical and renin–aldosterone axis in dogs with pituitary-dependent hypercortisolism

The medical records of 63 dogs with pituitary-dependent hypercortisolism (PDH) before and during treatment with trilostane were reviewed retrospectively. The correct trilostane dosage in dogs with PDH was based on the resolution of clinical signs and the results of an adrenocorticotropic hormone (ACTH) stimulation test. The mean (±SD) dose rate of trilostane to achieve good clinical control was 2.8 ± 1.0 mg/kg bodyweight. Trilostane treatment resulted in a significant decline in basal plasma cortisol concentrations. The median plasma ACTH concentration (39 pmol/L, range 7–132 pmol/L; n = 60) at the optimal trilostane dosage time was significantly higher (P < 0.001) than before treatment (13 pmol/L, range 2–102 pmol/L). These values did not overlap with plasma ACTH concentrations (range 212–307 pmol/L) of five PDH dogs with trilostane-induced hypocortisolism.The median cortisol/ACTH ratio in well-controlled dogs (0.23, range 0.03–2.5; n = 46) was significantly lower (P < 0.001) than before treatment (2.59, range 0.27–13.25). Trilostane treatment resulted in an insignificant decrease in plasma aldosterone concentration (PAC), but the median plasma renin activity (PRA) at the time the trilostane dosage was considered optimal (265 fmol/L/s, range 70–3280 fmol/L/s; n = 18) was significantly higher (P < 0.001) than prior to treatment (115 fmol/L/s, range 15–1330 fmol/L/s). Similarly, the median PAC/PRA ratio during trilostane treatment (0.16, range 0.003–0.92; n = 17) was significantly lower (P < 0.001) than before treatment (median 0.44, range 0.04–1.33). Trilostane affected both the hypothalamic-pituitary-adrenocortical and the renin–aldosterone axes. The results also suggested that basal plasma ACTH concentration may be used to detect trilostane overdosage.