Primary Urinary Bladder Tumors in Three Guinea Pigs (Cavia Porcellus).

Urinary bladder tumors are not common in guinea pigs, but case numbers being diagnosed have increased in the past years. The authors present 3 referred cases of primary urinary bladder tumors in pet guinea pigs diagnosed using diagnostic imaging (CT, radiography, and ultrasonography) and exploratory laparotomy. Excision was not possible in the first case as the tumor was located at the neck of the urinary bladder and the owner opted for intraoperative euthanasia. The second and third cases both had tumors originating from the apex of the urinary bladder. The third guinea pig went into cardiac arrest during surgery and resuscitation was unsuccessful. The tumor was removed from the urinary bladder using partial cystectomy in the second case and 1-month postsurgery ultrasonographic examination showed no signs of tumor reoccurrence. Late recognition is the main reason for a negative outcome, as by this time tumors are already large and extensive. Whenever prolonged symptoms of hematuria are present and urolithiasis has been ruled out, ultrasonography should be undertaken to determine if a urinary tumor is the cause. Rechecks should be scheduled on a regular basis for guinea pigs when a definitive diagnosis can not be made at the initial presentation for vague clinical signs, as outcome and survival can reduce significantly when definitive treatment is delayed.

Application of Moxidectin and Ultrasound-Aided Injection of Melarsomine During the American Heartworm Society Recommended Treatment Protocol in Dirofilaria immitis Infected Dogs.

The American Heartworm Society (AHS) recommends the three-dose alternate melarsomine therapeutic regimen, together with a macrocyclic lactone (ML) to reduce new infections and eliminate susceptible larvae and doxycycline against Wolbachia bacteria. Till now, only reports on ivermectin as an ML exist in the frame of this protocol. Between 2014 and 2020, the AHS protocol was used in 44 heartworm-positive dogs. Microfilaremic dogs were pretreated with prednisolone and clopidogrel for 1 week before the first moxidectin application. Moxidectin was applied on the 1st, 30th, 60th, and 90th therapeutic days. On the first day, dexamethasone and chloropyramine were used to avoid potential adverse effects caused by the destroyed microfilariae. During the 1st-28th days, doxycycline 10 mg/kg BID was given with probiotics. Adult heartworms were destroyed with melarsomine on the 60th, 90th, and 91st days. Butorphanol and dexamethasone were given just before melarsomine injections. The depth of the intramuscular injection site was determined by ultrasound examination of the lumbar muscles. From the 60th day, dalteparin was applied for 10 days to decrease the chance of pulmonary thromboembolism. Moxidectin did not cause adverse reactions, even in microfilaremic dogs. Gastrointestinal side effects of doxycycline were observed in three (6%) dogs, they recovered after symptomatic therapy and by lowering the initial dose to 5 mg/kg BID. Transient anorexia and diarrhea were found in one (2%), and coughing and mild dyspnea in one (2%) animal as systemic post-therapeutic complications of melarsomine. No local side effects were observed in 13 (30%) dogs, mild local side effects occurred in 29 (66%) patients, and severe local swelling in 2 (4%) cases. All dogs recovered clinically by the 120th day and no microfilaremia was seen that time. An antigen test performed in 37/44 animals on the 271st day was also negative in all cases.

Experimental assessment of three electrosurgical tissue-sealing devices in a porcine model.

Three electrosurgical tissue-sealing devices (EnSeal ETSDRC-01, LigaSure LS1500 and Thunderbeat TB-0535PC) were compared regarding sealing time (ST), maximum working temperature (WTmax) and the total (MTZtotal) as well as the collateral microscopic thermal injury zone (MTZcollat) using laparoscopic handpieces 5 mm in diameter on four types of tissue (liver, mesentery, cross striated muscle and spleen) in an in vivo porcine model. LigaSure had the lowest mean ST in spleen, mesentery, muscle and liver, followed by Thunderbeat and EnSeal with significant differences between all types of tissues and devices. The significantly lowest mean WTmax was obtained for EnSeal in mesentery, muscle and liver. LigaSure and EnSeal operated at the lowest temperature in spleen without a significant difference between them. Thunderbeat produced significantly higher temperature peaks in all cases. The lowest mean MTZtotal was caused by LigaSure and EnSeal in spleen, mesentery and muscle without significant differences between them, followed by the significantly higher values of Thunderbeat. Nevertheless, Thunderbeat produced the significantly lowest mean MTZtotal in the liver. EnSeal produced the lowest mean MTZcollat in the liver, followed by LigaSure and Thunderbeat showing significant differences. EnSeal and LigaSure produced the lowest mean MTZcollat in the spleen, mesentery and muscle without significant differences between them, followed by the significantly higher values of Thunderbeat. Based on the results of this study, Thunderbeat seems to be more invasive to tissue integrity (even without the activation of the ultrasonic scissor function) than EnSeal or LigaSure, that operate at lower temperatures and were found to cause negligible collateral thermal damage.

Longitudinal Volumetric Assessment of Ventricular Enlargement in Pet Dogs Trained for Functional Magnetic Resonance Imaging (fMRI) Studies.

BACKGROUND: Recent studies suggest that clinically sound ventriculomegaly in dogs could be a preliminary form of the clinically significant hydrocephalus. We evaluated changes of ventricular volumes in awake functional magnetic resonance imaging (fMRI) trained dogs with indirectly assessed cognitive abilities over time (thus avoiding the use of anaesthetics, which can alter the pressure). Our research question was whether ventricular enlargement developing over time would have any detrimental effect on staying still while being scanned; which can be extrapolated to the ability to pay attention and to exert inhibition. METHODS: Seven healthy dogs, 2-8 years old at the baseline scan and 4 years older at rescan, participated in a rigorous and gradual training for staying motionless (<2 mm) in the magnetic resonance (MR) scanner without any sedation during 6 minute-long structural MR sequences. On T1 structural images, volumetric analyses of the lateral ventricles were completed by software guided semi-automated tissue-type segmentations performed with FMRIB Software Library (FSL, Analysis Group, Oxford, UK). RESULTS AND CONCLUSION: We report significant enlargement for both ventricles (left: 47.46 %, right: 46.07 %) over time while dogs retained high levels of attention and inhibition. The results suggest that even considerable ventricular enlargement arising during normal aging does not necessarily reflect observable pathological changes in behavior.

Morphological evaluation of experimental autologous rectus fascia sheath vascular grafts used for arterial replacement in a dog model.

Although experimental autologous patch or tubular conduit vascular grafts made from the internal rectus fascia sheath (IRFS) have been reported in the literature, thorough morphological evaluation and verification of the histological arterialisation of such grafts are lacking. Four purpose-bred Beagle dogs were utilised to create eight arterial internal rectus fascia sheath (ARFS) grafts implanted between bisected ends of the external iliac arteries. Four out of the eight ARFS grafts were patent after three months. Haematoxylin-eosin and Azan staining verified that the grafts gained a vessel-like layered structure with the presence of large amounts of collagen fibres. Although the inner surface of the intact IRFS was originally covered with claudin-5-negative and pancytokeratin-positive mesothelial cells in control samples, the internal cells of the ARFS grafts became claudin-5 positive and pancytokeratin negative like in intact arteries. Spindle-shaped cells of the wall of ARFS grafts were α-smooth muscle actin (α-SMA) positive just like the smooth muscle cells of intact arteries, but α-SMA immunoreactivity was negative in the intact IRFS. According to these findings, the fibroblast cells of the ARFS graft have changed into myofibroblast cells. The study has proved that ARFS grafts may be used as an alternative in arterial replacement, since the graft becomes morphologically and functionally similar to the host vessel via arterialisation.

Subarachnoid pressures and cardiorespiratory parameters during cisternal myelography in isoflurane anaesthetized dogs.

OBJECTIVE: To measure subarachnoid pressures, systemic circulatory and respiratory effects, and to calculate cerebral perfusion pressure during cisternal myelography. STUDY DESIGN: Prospective clinical study. ANIMALS: Forty-three client owned dogs with clinical signs of spinal disease, weighing 6-56 kg. METHODS: Dogs were premedicated with butorphanol and diazepam intravenously (IV) and anaesthesia was induced with propofol and maintained with isoflurane vaporized in oxygen. Ventilation was spontaneous. Heart and respiratory rates, invasive mean arterial blood pressure (MAP), end tidal carbon dioxide and isoflurane concentration were measured continuously. Initial subarachnoid pressure (SaP0 ) was measured in the cisterna magna with a needle pressure gauge. Iohexol 0.3 mL kg(-1) was injected at a rate of 4.1 mL minute(-1) into the cerebellomedullary cistern. The SaP was recorded during and at 120 seconds after contrast administration. The maximum SaP (SaPmax ) and minimum calculated cerebral perfusion pressure (CPPmin ) were recorded for each case. RESULTS: Prior to contrast injection, mean ± SD, MAP was 73 ± 20 mmHg and SaP0 was 10 ± 3 mmHg. The cerebral perfusion pressure (CPP) was 64 ± 20 mmHg. The contrast injection increased the SaP0 to 73 ± 33 mmHg (SaPmax ). After injection, MAP increased to 97 ± 25 mmHg and the CPP decreased to 14 ± 34 mmHg. A negative correlation was found between the lowest CPP and body weight (ρ = -0.77, p < 0.0001). Nine dogs had bradycardia, apnoea and hypertension, 21 dogs had at least one of these signs. The number of clinical signs showed significant correlation with body weight (ρ = -0.68, p < 0.0001), SaPmax (ρ = -0.66, p < 0.0001) and CPPmin (ρ = -0.73, p < 0.0001). CONCLUSIONS AND CLINICAL RELEVANCE: Cerebral perfusion can severely decrease during cisternal myelography using the standard dose of iohexol. Bradycardia, apnoea and systemic hypertension were associated with decreased CPP.

Pressure-volume index-based volume calculation of contrast medium for atlanto-occipital myelography in dogs.

Subarachnoid pressure recordings were made during atlanto-occipital myelography in 45 dogs with clinical signs of spinal disease. Iohexol was injected at a dosage of 0.3 ml/kg body weight and simultaneous pressure values were recorded in the cerebellomedullary cistern. The mean subarachnoid pressure was 9 ± 3 mmHg before and 70 ± 32 mmHg at the end of administration. From the pressure change induced by the volume load, the pressure-volume index (PVI) of the subarachnoid space was calculated and found to be in close correlation with body weight and the crown-rump length (r = 0.94 and 0.87). Using the estimated PVI values, the appropriate volume of contrast medium can be calculated for an animal according to body weight. Dogs of a large body size require relatively less contrast medium than small-sized dogs (range 0.17-0.35 ml/kg). This calculated volume is unlikely to increase the subarachnoid pressure above 40 mmHg as a specific pressure limit. Using these data, simplified recommendations for the choice of contrast medium volumes have been generated.

Experimental results of using autologous rectus fascia sheath for venous patch grafts in dogs.

Autologous vascular patch grafts developed from the internal rectus sheath were implanted onto the bilateral common iliac vein and jugular vein of 4 experimental beagle dogs. During the development and implanting of the grafts no technical difficulties or perioperative complications were encountered. The follow-up lasted 6 months and 3 months in the case of the common iliac vein grafts and the jugular grafts, respectively. In the postoperative period, the morphological and functional characteristics of the implanted venous sections were examined by Doppler ultrasonography and CT angiography. Normal patency was detected, and none of these check-ups showed obturation or stenosis. The histological survey showed no mesothelial cell layer, but the insides of the grafts showed total restructuring and were covered by a normal endothelial layer. No difference could be detected between samples harvested 3 and 6 months after implanting. The immunohistochemical examinations using anti-claudin-5 and anti-CD31 antibodies confirmed the preliminary results of the histological examinations that the luminal surfaces of the implanted grafts developed a differentiated monolayer endothelium which was free of degenerative and inflammatory signs. The control examinations show the suitability of the internal rectus sheath as a venous wall donor.

Vertebral osteomyelitis and meningomyelitis caused by Pasteurella canis in a dog--clinicopathological case report.

A clinicopathological case study of vertebral osteomyelitis caused by Pasteurella canis in a 2.5-year-old male Jack Russell Terrier is presented. The case was characterised by a chronic course with signs of spinal pain and acute paraplegia. The diagnosis was established by radiography, myelography, post-myelographic CT examination, and laboratory tests including routine blood work and cerebrospinal fluid (CSF) cytology, and confirmed by postmortem pathological and microbiological examinations. Diagnostic imaging showed severe osteolysis, ventral spondylosis and spinal cord compression at the 4th and 5th lumbar vertebrae. The blood tests revealed mild leukocytosis and anaemia, while CSF cytology showed lymphocytic and mononuclear pleocytosis. Necropsy demonstrated severe osteomyelitis and meningomyelitis, but the source of infection could not be established. To the authors' knowledge, this is the first description of canine vertebral osteomyelitis caused by this organism.

Redox status of dogs with non-hodgkin lymphomas. An ESR study.

Free radical and antioxidant parameters in healthy dogs (n=10) and dogs with non-Hodgkin lymphomas (n=11) were measured in blood and lymph node tissue samples before chemotherapy. Enzymatic and other biochemical measurements were performed. We found that (i) free radical concentrations based on ESR spectra of tissues correlated with higher proliferative character; (ii) lymphoma cases showed an impaired antioxidant status; (iii) tumors with low oxidative burst capacity and higher reduced/oxidized glutathione ratio responded better to chemotherapy; and (iv) affected blood and lymph nodes were under strong oxidative stress.