This study was designed to test analgesia, duration, and cardiovascular changes induced by meperidine (MEP) and oxymorphone (OXY) following methoxyflurane (MOF) and halothane (HAL) anesthesia. Eight healthy dogs were given atropine and acepromazine, and anesthesia was induced with thiamylal and maintained with 1.5 minimal alveolar concentration of MOF or HAL for 1 hour during controlled ventilation. Eight treatments were given with each anesthetic: 3 with MEP (0.5, 1.0, and 2.0 mg/kg, IV), 3 with oxymorphone (OXY; 0.05, 0.1, and 0.2 mg/kg, IV), and 2 placebos with sterile water. Test drugs were given at the end of anesthesia when early signs of recovery were evident. Minimal threshold stimulus/response nociception was assessed by use of an inflatable soft plastic colonic balloon. Blood pressures and pulse rate were measured with a noninvasive monitor. Meperidine and OXY were found to be effective analgesics and could be reversed with naloxone. Intravenous administration of 2.0 mg of MEP/kg provided analgesia for 36 +/- 6 minutes and 39 +/- 15 minutes after MOF and HAL, respectively. In contrast, OXY was effective at all 3 doses with effects of IV administration of 0.2 mg of OXY/kg lasting 154 +/- 13 minutes and 152 +/- 12 minutes, after MOF and HAL, respectively. Analgesia could not be demonstrated after anesthesia for acepromazine, MOF, or HAL. Blood pressure was not changed by either anesthetic nor was it influenced by MEP or OXY. Pulse rate was significantly depressed by the higher doses of OXY following HAL, but was not changed by MEP following either anesthetic. This study demonstrated the longer duration of analgesia of OXY. In addition, we could not find that analgesia was provided by either MOF or HAL following recovery from anesthesia.

Serial sections of bone and soft tissue from the metacarpophalangeal joints of 2 mature and 2 immature horses were evaluated for substance P immunoreactive sensory nerve fibers. Formalin-fixed specimens were sectioned, either nondemineralized or demineralized with formic acid or EDTA. Rabbit antiserum to substance P (SP) was used in the strep. tavidin-biotin-peraxidase complex method for immunolocalization of SP antigen, and staining with 3,3'- diaminobenzidine was used for permanent identification of SP fibers. Abundant sensory nerve fibers were identified in the joint capsule, synovial membrane subintimal layers, collateral ligaments, suspensory ligament and distal sesamoidean ligament attachments to the sesamoid bones, and the periarticular periosteal layers. Sparse SP-immunoreactive nerve fibers were found in subchondral bone plates of the metacarpus, proximal first phalanx, and dorsal articular surface of the sesamoid bones. Most SP fibers were associated with blood vessels in the small cancellous spaces and haversian canals of the subchondral bone. The deeper marrow spaces contained increased numbers of SP sensory fibers; a few appeared in small groups and as several SP-immunoreactive fibers in a larger nerve. Cortical bone contained only a few SP fibers in the haversian canals. Substance P fibers were not identified in the osteocytic lacunae, canaliculi, or the bony lamellae of the haversian systems of the subchondral bone plate, and its extension to the metaphyseal and diaphyseal cortical bone. Equine metacarpophalangeal joint soft tissues have an abundant sensory nerve supply, similar to that of other species. However, the subchondral bone plate also has sparse sensory nerve fibers, which is a unique finding, and may help explain signs of bone pain associated with disease states of the fetlock.

In canine and feline populations, the number of neoplasm cases continues to increase around the world. Attempts are being made in centres of research to identify new biomarkers that speed up and improve the quality of oncological diagnostics and therapy in human and animal tumour patients. Cyclooxygenase-2 (COX-2) is a promising biomarker with increasing relevance to human oncology, but as yet with less application in veterinary oncology. The expression of COX-2 increases significantly during pathological processes involving inflammation, pain or fever. It is also overexpressed in humans presenting various types of tumours and in selected types of tumours in animals, particularly in dogs. This article discusses the expression of COX-2 in canine and feline tumours, the importance of COX-2 as a biomarker with diagnostic, therapeutic, prognostic and predictive relevance in oncology, and the clinical significance of inhibiting COX-2 overexpression in tumours.

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in veterinary medicine. They are used in pain control and in anti-inflammatory and antipyretic therapies. Some NSAIDs, e.g piroxicam, also have a documented anticancer effect. The objective of this study was to evaluate which of the commonly used NSAIDs (etodolac, flunixin, tolfenamic acid, carprofen, and ketoprofen) are cytotoxic to the D-17 cell line of canine osteosarcoma. The viability of the cells was evaluated using the MTT assay. Four independent repetitions were performed and the results are given as the average of these values; EC₅₀ values (half maximal effective concentration) were also calculated. The analysis of results showed that carprofen and tolfenamic acid displayed the highest cytotoxicity. Other drugs either did not provide such effects or they were very poor. For carprofen, it was possible to determine an EC₅₀ which fell within the limits of concentrations obtainable in canine serum after the administration of routinely used doses. The results are promising but further studies should be conducted to confirm them, since this study is only preliminary. The possibility of introducing carprofen and tolfenamic acid into the routine treatment of osteosarcoma in dogs should be considered.

Lameness is a painful and debilitating condition that affects dairy cows worldwide. The aim of this study was to determine the plasma concentration of norepinephrine, β-endorphin, and substance P in dairy cows with lameness and different mobility scores (MS). A total of 100 Friesian and Jersey cows with lameness (parity range: 1–6; weight: 400–500 kg; milk yield: 22–28 L a day, and lactation stage less than 230 days) were selected. Animals were selected and grouped according to MS (MS 0–3; n = 25), and plasma concentration of norepinephrine, substance P, and β-endorphin was measured using ELISA. Cows with MS 3 had higher plasma concentrations of norepinephrine and substance P and lower plasma concentrations of β-endorphins when compared to MS 0 cows. Variations in plasma concentration of norepinephrine, substance P, and β-endorphin could be associated with intense pain states in dairy cows with lameness, but are insufficient to differentiate these states from the mildest pain states. Further studies are necessary in order to evaluate the potential use of these biomarkers in the detection of chronic bovine painful conditions.

While the current tools to assess canine postoperative pain using physiological and behavioural parameters are reliable, an objective method such as the parasympathetic tone activity (PTA) index could improve postoperative care. The aim of the study was to determine the utility of the PTA index in assessing postoperative analgaesia. Thirty healthy bitches of different breeds were randomly allocated into three groups for analgaesic treatment: the paracetamol group (GPARAC, n = 10) received 15 mg/kg b.w., the carprofen group (GCARP, n = 10) 4 mg/kg b.w., and the meloxicam group (GMELOX, n = 10) 0.2 mg/kg b.w. for 48 h after surgery. GPARAC was medicated orally every 8 h, while GCARP and GMELOX were medicated intravenously every 24 h. The PTA index was used to measure the analgaesia–nociception balance 1 h before surgery (baseline), and at 1, 2, 4, 6, 8, 12, 16, 20, 24, 36, and 48 h after, at which times evaluation on the University of Melbourne Pain Scale (UMPS) was made. The baseline PTA index was 65 ± 8 for GPARAC, 65 ± 7 for GCARP, and 62 ± 5 for GMELOX. Postoperatively, it was 65 ± 9 for GPARAC, 63 ± 8 for GCARP, and 65 ± 8 for GMELOX. No statistically significant difference existed between baseline values or between values directly after treatments (P = 0.99 and P = 0.97, respectively). The PTA index showed a sensitivity of 40%, specificity of 98.46% and a negative predictive value of 99.07%. Our findings suggest that the PTA index measures comfort and postoperative analgaesia objectively, since it showed a clinical relationship with the UMPS.

OBJECTIVE To assess the effect of low-level laser therapy (LLLT) on markers of synovial inflammation and signs of pain, function, bone healing, and osteoarthritis following tibial plateau leveling osteotomy (TPLO) in dogs with spontaneous cranial cruciate ligament rupture (CCLR). ANIMALS 12 client-owned dogs with unilateral CCLR. PROCEDURES All dogs were instrumented with an accelerometer for 2 weeks before and 8 weeks after TPLO. Dogs were randomly assigned to receive LLLT (radiant exposure, 1.5 to 2.25 J/cm2; n = 6) or a control (red light; 6) treatment immediately before and at predetermined times for 8 weeks after TPLO. Owners completed a Canine Brief Pain Inventory weekly for 8 weeks after surgery. Each dog underwent a recheck appointment, which included physical and orthopedic examinations, force plate analysis, radiography and synoviocentesis of the affected joint, and evaluation of lameness and signs of pain, at 2, 4, and 8 weeks after surgery. Select markers of inflammation were quantified in synovial fluid samples. Variables were compared between the 2 groups. RESULTS For the control group, mean ground reaction forces were greater at 2 and 4 weeks after TPLO and owner-assigned pain scores were lower during weeks 1 through 5 after TPLO, compared with corresponding values for the LLLT group. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the LLLT protocol used had no beneficial effects on signs of pain or pelvic limb function following TPLO. Further research is necessary to evaluate the effects of LLLT and to determine the optimum LLLT protocol for dogs with CCLR.

OBJECTIVE To evaluate effects of pneumoperitoneum created with warmed humidified CO2 (WHCO2) during laparoscopy on core body temperature, cardiorespiratory and thromboelastography variables, systemic inflammation, peritoneal response, and signs of postoperative pain in healthy mature dogs. ANIMALS 6 mature purpose-bred dogs. PROCEDURES In a randomized crossover study, each dog was anesthetized twice, and pneumoperitoneum was created with standard-temperature CO2 (STCO2; 22°C and 0% relative humidity) and WHCO2 (37°C and 98% relative humidity). Data were collected during each procedure, including core body temperature, cardiorespiratory and thromboelastography variables, and inflammatory biomarkers. Peritoneal biopsy specimens were collected and evaluated with scanning electron microscopy. Dogs were assessed for signs of postoperative pain. RESULTS Mean core body temperature was significantly lower (35.2°C; 95% confidence interval, 34.5° to 35.8°C) with WHCO2 than with STCO2 (35.9°C; 95% confidence interval, 35.3° to 36.6°C) across all time points. Cardiac index increased during the procedure for both treatments but was not significantly different between treatments. Thromboelastography variables did not differ significantly between treatments as indicated by the coagulation index. Subjective evaluation of peritoneal biopsy specimens revealed mesothelial cell loss with STCO2. There was no significant difference in circulating C-reactive protein or interleukin-6 concentrations. There was a significant increase in the number of postoperative pain scores > 0 for the WHCO2 treatment versus the STCO2 treatment. CONCLUSIONS AND CLINICAL RELEVANCE Analysis of these data suggested that effects on evaluated variables attributable to the use of WHCO2 for creating pneumoperitoneum in healthy mature dogs undergoing laparoscopy did not differ from effects for the use of STCO2.