FC-13 Molecular markers in canine T-cell lymphoma

A previous study described cutaneous lymphocytosis (CL) in 23 cats. The process resembles cutaneous pseudolymphoma in humans, a heterogeneous group of benign reactive proliferations of well-differentiated lymphocytes in the skin of humans. Morphological and immunophenotypic characteristics do not offer reliable criteria to accurately predict the clinical outcome of feline CL or pseudolymphoma in humans. Presence of clonal cell populations is more consistent with a neoplastic process. In a previous study, feline CL lesions (20 cats) were evaluated for clonality using PCR, and only two cats had monoclonal T-cell populations. Because false-negative results may occur, the purpose of this study was to repeat the PCR using a revised primer set based on analysis of additional feline T-cell receptor γ (TCRγ) sequences. DNA was isolated from 29 skin lesions and six internal organs of 20 cats. DNA integrity was assessed by glyceraldehyde-3-phosphate dehydrogenase PCR. Polymerase chain reaction clonality was performed using the revised primer set specific for feline TCRγ, and duplicate samples were evaluated. The PCR products were assessed by heteroduplex analysis. Clonal rearrangement of TCRγ was detected in 14 cats (24 of 35 tissues: 21 of 29 skin lesions and three of six internal organs); eight of these cats are still alive and six were euthanized. Monoclonal populations were seen in three of five cats that had involvement of internal organs. These findings indicate that feline CL is best considered as a slowly progressive process which may be reactive, but often evolves into a low-grade indolent lymphoma.
Funding: George H. Muller Fund for Research in Dermatology.     

Determination of the Lability Characteristics of Lead,Cadmium and Zinc in a Polluted Mediterranean Brackish-Marine Interface System

Labile and non-labile fractions of zinc, lead and cadmium are studied throughout the mixing process of the waters of a small brackish, polluted lake (Koumoundouros lake) with the seawaters of the adjacent Elefsis Bay, employing Differential Pulse Anodic Stripping Voltammetry (DPASV) and Chelex-100 resins. The metal fractions were classified according to their relative lability as: very labile, moderately labile, slowly labile andinert. Their distribution is determined mainly by their affinity to complexation to organic and inorganic ligands and the changes of pH and salinity. Furthermore, the impact of salinity and pH on lability was also studied using laboratory simulation experiments. Interesting observations on the phenomena recorded include: (a) positive correlation between salinity and the very labilefraction of the metals, attributed to the formation of ion pairs and complexes of metals with chlorine ions; (b) increase of the presence of the less labile metal species by increasing pH; (c) relatively strong correlation of the dissolved organic carbon with the slowly labile and inert fractions of Pb and Zn, respectively.     

A minimally invasive method for clinical trans‐diaphragmatic pressure measurement in anaesthetized dogs

ObjectiveTo measure trans-diaphragmatic pressures, as an indication of diaphragmatic contractility, in anaesthetized dogs breathing normally, or during inspiratory obstruction (Mueller’s manoeuvre) in order to assess if the method is practicable for use in clinical circumstances.Study designPilot study.AnimalsTwenty eight client-owned dogs, ASA I or II, 1–10 years old, 5–30 kg bodyweight, which required anaesthesia for surgery, and were to be positioned in lateral recumbency.MethodsFollowing a standardized regimen of premedication and anaesthetic induction, anaesthesia was stabilized and maintained with isoflurane. Two commercially available balloon catheters were introduced orally, and advanced, one into the stomach and one into the mid-third of the oesophagus. Oesophageal and gastric pressures were measured from these catheters, and trans-diaphragmatic pressure (P_di) calculated and recorded continuously. At three separate time points during anaesthesia, for one breath, inspiration was obstructed (Mueller’s manoeuvre) and P_di was measured.ResultsPlacement of the catheters in the stomach was not easy, and failed in three cases. In five dogs, their size resulted in failure of correct placement of catheters. Good traces of all three pressures reflecting respiratory cycles were obtained from 20 dogs. During normal spontaneous breathing (mean ± SD [range]) P_di was 5 ± 2.1 (3–10) mmHg. During Mueller’s manoeuvre, P_di was 14.6 ± 4.5 (9–21) mmHg. Abnormal waveforms were seen included cardiac oscillations (five dogs), inadequate intra-gastric pressure tracing (one dog), deflections with a double peak (one dog), and multiple artifacts when there was increased heart rate and tachypnoea (two dogs in response to surgery).Conclusions and clinical relevanceMeasurement of trans-diaphragmatic pressure with balloon catheters was practicable in suitably sized dogs anaesthetized for clinical purposes and might be a useful tool in the assessment of diaphragmatic function. A range of catheters are required if the technique is to work in all dogs.     

Anesthesia and perioperative management of a pneumonectomized dog

Although left- or right-sided pneumonectomy is tolerated by normal dogs, complications impacting the respiratory, cardiovascular, and gastrointestinal systems are not uncommon. Pneumonectomy in dogs results in secondary changes in the remaining lung, which include: decreased compliance and vital capacity; and increased pulmonary vascular resistance potentially leading to right ventricular hypertrophy. Such alterations make the anesthetic management of an animal with one lung particularly challenging. This report describes a dog with a history of left pneumonectomy due to Aspergillus fumigatus pneumonia 3 yr before presentation. The dog presented with a vaginal wall prolapse, and surgical resection of the protruding vaginal wall, ovariectomy, and prophylactic gastropexy were performed. Anesthesia was induced with midazolam, fentanyl, and propofol and was maintained with isoflurane using intermittent positive pressure ventilation and a constant rate infusion of fentanyl. Epidural anesthesia was also used. Recovery and postoperative management were uncomplicated. Intensive hemodynamic and respiratory monitoring and appropriate response and treatment of any detected abnormalities, taking into consideration the pathophysiologic alterations occurring in a pneumonectomized animal, are required for successful perianesthetic management.     

ASSESSMENT OF SENTINEL LYMPH NODE METASTASIS IN CANINE MAMMARY GLAND TUMORS USING COMPUTED TOMOGRAPHIC INDIRECT LYMPHOGRAPHY

In the staging process of the breast cancer, demonstrating metastasis of the sentinel lymph node (SLN) has an important prognostic value, in both humans and animals. The aim of this prospective case‐control study was to determine the diagnostic value of computed tomographic indirect lymphography (CT‐LG) for detecting SLN metastasis in dogs with mammary cancer. Thirty‐three female dogs with tumors in the abdominal and inguinal mammary glands were prospectively selected and subjected to CT‐LG, 1 and 5 min after injection of 1 ml of contrast agent (iopamidol) in the subareolar tissue of the neoplastic and the contralateral normal mammary glands. The pattern of postcontrast opacification, degree of postcontrast enhancement, and size and shape were assessed in 65 SLNs in total and were correlated with histopathological findings. The absence of opacification or heterogeneous opacification 1 min after contrast medium injection showed the highest sensitivity, specificity, and accuracy (93%, 100%, and 98.4%, respectively). In images taken 1 min after injection, an absolute density value lower than 444 Hounsfield units (HU) in the center of the SLN also provided significant sensitivity and specificity (93.8% and 75%, respectively). The size and shape of the SLN (maximum and minimum diameter, maximum/minimum diameter ratio, maximum diameter/height of fifth thoracic vertebral body ratio) showed the lowest sensitivity and specificity. Results of this study support the hypothesis that CT‐LG could help in the assessment of SLN metastasis in cases of mammary gland tumors in dogs.     

Comparison of respiratory function during TIVA (romifidine,ketamine, midazolam) and isoflurane anaesthesia in spontaneously breathing ponies Part I: blood gas analysis and cardiorespiratory variables

ObjectiveTo compare pulmonary function and gas exchange in ponies during maintenance of anaesthesia with isoflurane or by a total intravenous anaesthesia (TIVA) technique.Study designExperimental, cross–over study.AnimalsSix healthy ponies weighing mean 286 (range 233–388) ± SD 61 kg, age 13 (9-16) ± 3 years.MethodsThe ponies were anaesthetized twice, a minimum of two weeks apart. Following sedation with romifidine [80 μg kg^?1 intravenously (IV)], anaesthesia was induced IV with midazolam (0.06 mg kg^?1) and ketamine (2.5 mg kg^?1), then maintained either with inhaled isoflurane (Fe’Iso = 1.1 vol%) (T-ISO) or an IV infusion of romifidine (120 μg kg^?1 hour^?1), midazolam (0.09 mg kg^?1 hour^?1 IV) and ketamine (3.3 mg kg^?1 hour^?1) (T-TIVA). Ponies were placed in lateral recumbency. Breathing was spontaneous and Fi’O₂ 60%. After an instrumentation/stabilisation period of 30 minutes, arterial and mixed venous blood samples were taken simultaneously every 10 minutes for 60 minutes and analysed immediately. Oxygen extraction ratio (O₂ER) and venous admixture were calculated. Tidal volume (TV), minute volume (MV), respiratory rate (f_R), packed cell volume (PCV), arterial blood pressure and heart rate (HR) were measured and recorded. Data were analysed with mixed model anova (a = 0.05). Treatments were compared overall and at two selected time points (T30 and T60) using Bonferroni correction.ResultsArterial and mixed venous partial pressures of O₂ and CO₂, and TV were significantly lower and MV and f_R were higher in T-TIVA compared to T-ISO. Venous admixture did not differ between treatments. O₂ER was significantly higher in T-TIVA. Mean arterial pressure was higher and HR was lower in T-TIVA compared to T-ISO.Conclusions and clinical relevanceWhilst arterial CO₂ was within an acceptable range during both protocols, the impairment of oxygenation was more pronounced with the T-TIVA evidenced by lower arterial and venous oxygen partial pressures.     

Comparison of respiratory function during TIVA and isoflurane anaesthesia in ponies Part II: breathing patterns and transdiaphragmatic pressure

ObjectiveTo compare breathing patterns and transdiaphragmatic pressure during total intravenous (TIVA) and isoflurane anaesthesia in ponies.Study designExperimental, cross–over study.AnimalsSix healthy ponies weighing 286 (233–388) ± 61 kg, age 13 (9–16) ± 3 years.MethodsFollowing premedication with romifidine [80 μg kg^?1 intravenously (IV)], general anaesthesia was induced with midazolam (0.06 mg kg^?1 IV) and ketamine (2.5 mg kg^?1 IV) and maintained with either isoflurane (Fe’Iso = 1.1%) (T-ISO) or an IV combination of romifidine (120 μg kg^?1 per hour), midazolam (0.09 mg kg^?1 hour^?1) and ketamine (3.3 mg kg^?1 hour^?1) (T-TIVA), while breathing 60% oxygen (FIO₂). The circumference changes of the rib cage (RC) and abdominal compartment (ABD) were recorded using respiratory ultrasonic plethysmography (RUP). Balloon tipped catheters were placed in the distal oesophagus and the stomach and maximal transdiaphragmatic pressure (P_{di max)} was calculated during Mueller's manoeuvre.ResultsThe breathing pattern T-ISO was more regular and respiratory rate significantly lower compared with T-TIVA. Ponies in T-TIVA showed regularly appearing sighs, which were never observed in T-ISO. Different contribution of the RC and ABD compartments to the breathing pattern was observed with a smaller participation of the RC to the total volume change during T-ISO. Transdiaphragmatic pressures (mean 13.7 ± SD 8.61 versus 23.4 ± 7.27 cmH₂O, p < 0.0001) were higher in T-TIVA compared to T-ISO. The sum of the RC and ABD circumferential changes was lower during T-TIVA compared to T-ISO (6.32 ± 4.42 versus 11.72 ± 4.38 units, p < 0.0001).Conclusion and clinical relevanceMarked differences in breathing pattern and transdiaphragmatic pressure exist during inhalation- and TIVA and these should be taken into account for clinical estimation of anaesthetic depth.