Plasma concentration and cardiovascular effects of lidocaine during continuous epidural administration in dogs anesthetized with isoflurane.

The cardiovascular effects of continuous epidural administration (CEA) of lidocaine were investigated in anesthetized dogs. Loading epidural injections of 2, 4, or 6 mg/kg of lidocaine were followed by CEA with 1, 2, or 3 mg/kg/hr lidocaine, respectively, for 2 hr under 2.0% isoflurane anesthesia. Heart rate, direct blood pressure, cardiac index, and stroke volume decreased dose-dependently during CEA, whereas systemic vascular resistance did not significantly differ with dose, and no characteristic changes were observed in any groups. Plasma lidocaine concentration reached a steady state during CEA and increased in a dose-dependent manner. Circulatory suppression caused by lidocaine CEA was not attributable to peripheral vasodilation, but rather to the direct cardiac action of systemic lidocaine absorption from the peridural space.

Priming effects of lipopolysaccharide and inflammatory cytokines on canine granulocytes.

Granulocytes play a pivotal role in natural immunity. Under inflammatory conditions, granulocytes are universally primed by several agents, such as endotoxins and inflammatory cytokines. Primed granulocytes exert potent adhesiveness, chemotaxis, phagocytosis and reactive oxygen species (ROS) production, effectively eliminating invading agents. Reactivity against priming agents is known to vary with species; however, there have been few reports on the effects of priming agents on canine granulocytes. In the present study, we assayed the priming effects of lipopolysaccharide (LPS), recombinant canine tumor necrosis factor-alpha (rcTNF-alpha) and recombinant canine granulocyte macrophage colony-stimulating factor (rcGM-CSF) on canine granulocyte function in vitro. Isolated recombinant canine were primed with various concentrations of LPS, rcTNF-alpha and rcGM-CSF, and CD11b expression was assayed. Furthermore, actin polymerization, phagocytosis and ROS production were then assayed at primer concentrations where enhancement of CD11b expression was observed. LPS did not enhance canine granulocyte function. Phagocytosis and actin polymerization were not enhanced by priming agents; however, rcTNF-alpha and rcGM-CSF enhanced CD11b expression and ROS production in canine granulocytes. These results suggest that priming effects are mainly reflected in CD11b expression and ROS production, with rcGM-CSF and rcTNF-alpha having a priming effect similar to that observed in humans.

Effects of lidocaine hydrochloride on canine granulocytes, granulocyte CD11b expression and reactive oxygen species production.

Lidocaine hydrochloride (Lido) is widely used for analgesia in veterinary medicine; however, in humans, it has been suggested that Lido attenuates granulocyte functions, such as adhesion and reactive oxygen species (ROS) production. Thus, Lido may affect canine granulocyte function; however, there have been no reports on the effects of Lido on canine granulocyte function. Thus, we studied the effects of Lido on canine granulocyte CD11b expression and ROS production. We further studied the effects of Lido on the priming of canine granulocyte CD11b expression and ROS production by recombinant canine granulocyte macrophage colony stimulating factor (rcGM-CSF). Isolated granulocytes were incubated with 3, 30 or 300 microg/ml Lido, or with Lido followed by priming with 5 ng/ml rcGM-CSF. CD11b was detected by the immune fluorescent antibody method, and the mean fluorescence intensity (MFI) was assayed by flow cytometry. ROS production was assessed by the peak time (PT) of ROS production and area under the luminol reaction curve (AUC), which represents total ROS production quantity against opsonized zymosan stimuli. Only 300 microg/ml Lido (tissue level observed by regional block) significantly attenuated both the MFI of CD11b and its enhancement by rcGM-CSF. Moreover, at this concentration, the AUC and its enhancement by rcGM-CSF were significantly attenuated by Lido; in contrast, Lido did not affect PT. In conclusion, Lido suppressed granulocyte adhesion to the endothelium and antiseptic capability by suppressing CD11b expression and/or ROS production. Particular care should thus be exercised when performing regional anesthesia block using Lido.

Serum alpha-1-acid glycoprotein concentration in clinically healthy puppies and adult dogs and in dogs with various diseases.

BACKGROUND: alpha-1-acid glycoprotein (AGP) is an acute-phase protein and a serum marker of inflammation and neoplasia in humans. AGP concentrations in diseased dogs and the potential effects of age, breed, and sex have not been elucidated. OBJECTIVE: The purpose of this study was to examine differences in AGP concentration based on age, sex, and breed in a large population of clinically healthy dogs and to compare AGP concentrations in dogs with various diseases. METHODS: Serum was obtained from clinically healthy puppies (n=74) and adults (n=172) of both sexes, and included mongrels (n=205) and Beagles (n=41). Serum also was obtained from 192 dogs with various diseases, including 8 with pyometra that were sampled before, and 1, 2, 3, and 10 days after surgery. AGP concentration was measured by single radial immunodiffusion. Statistical comparisons were made among age, sex, breed, and disease groups. RESULTS: Serum AGP in healthy adult mongrels was 364+/-106 mg/L (reference interval, 152-576 mg/L). AGP was lowest in newborns (n=11, 122+/-54 mg/L) and gradually increased to adult levels by 3 months of age. Median AGP concentration was highest in dogs with parvovirus (n=17, 2100 mg/L), distemper (n=7, 1250 mg/L), and pyometra (n=18, 2480 mg/L) and was also significantly higher in dogs with acute filariasis, renal failure, urolithiasis, pancreatitis, hepatitis, trauma, hyperadrenocorticism, and immune-mediated hemolytic anemia. Dogs with acute filariasis and acute hepatopathy had significantly higher AGP concentrations than dogs with chronic filariasis and chronic hepatopathy. Serum AGP concentration decreased gradually following surgery for pyometra but remained increased after 10 days (896+/-175 mg/L). CONCLUSIONS: Because of significantly lower AGP in puppies, the age of dogs should be considered when using AGP as a marker of disease. Serum AGP may be a useful marker of inflammatory disease in dogs and may help differentiate acute and chronic stages of disease.

Relative nerve blocking properties of bupivacaine and ropivacaine in dogs undergoing brachial plexus block using a nerve stimulator.

In the present study, the efficacy of a nerve stimulator in performing brachial plexus block (BPB) in dogs was investigated. The nerve blocking effects of bupivacaine and ropivacaine for BPB were also compared. Twelve beagles were allocated to groups based on the following treatments: conventional BPB with 0.5% bupivacaine (0.5% BupiM group) or BPB with 0.5% bupivacaine, 0.5% ropivacaine or 0.75% ropivacaine and a nerve stimulator (the 0.5% BupiS, 0.5% RopiS and 0.75% RopiS groups, respectively). After BPB, nerve blocking effects were assessed based on sensory blockade in several cutaneous areas and knuckling. The ratio of full block (blockade in all cutaneous areas) for 0.5% BupiM was 25%, and that for 0.5% BupiS was significantly higher, 75% (p<0.05). For the 0.5% BupiS, 0.5% RopiS and 0.75% RopiS groups, the average duration of full block was 387, 184 and 275 min, respectively, and the average duration of knuckling was 703, 460 and 421 min, respectively. The duration of full block and knuckling for the two ropivacaine groups was shorter compared with that of the 0.5% BupiS group. In conclusion, when using bupivacaine and ropivacaine for BPB in dogs, it is worth noting that there are differences in onset time and duration and that effective perioperative analgesia can be achieved depending on the intended use.

Evaluation of immunological status in tumor-bearing dogs.

The purpose of this study was to evaluate immunological status in dogs with cancers at different stages, in comparison with normal dogs. The population of canine peripheral blood lymphocytes (cPBL), lymphocyte phenotypes, interleukin (IL)-6 activity and alpha 1-acid glycoprotein (alpha(1)-AG) level were analyzed. The tumor-bearing dogs had higher numbers of leukocytes than normal dogs, the count being higher in dogs with more advanced tumors. In the tumor-bearing dogs, differential leukocyte counts revealed higher percentages of inflammatory cells such as neutrophils, acidophils and monocytes, and lower numbers of CD4(+)T cells, than in normal dogs, the lymphocyte counts becoming much lower with tumor progression. In the tumor-bearing dogs, the CD8(+)T cell count at the early tumor stage was similar to that in normal dogs, but decreased with tumor progression, possibly reflecting the development of humoral immunity (Th2). Plasma IL-6 and TGF-beta activities were high in the tumor-bearing dogs. The plasma alpha(1)-AG concentration was also significantly high in the tumor-bearing dogs. Our findings suggest that assay of IL-6, TGF-beta and alpha(1)-AG may be very useful for prognostication in dogs with cancer, and that anti-tumor immunity is potently suppressed in such dogs.

Intraoperative spinal ultrasonography in two dogs with spinal disease.

Ultrasonography was performed during spinal surgery on two dogs that were suspected of having intramedullary lesions by myelography and magnetic resonance imaging. Ultrasonographically, the pathologic conditions of the spinal canal or cord were adequately imaged during surgery in both dogs. On the basis of ultrasonographic findings, a biopsy was obtained in Patient 1 and removal of the lesion was accomplished in Patient 2. Histopathologic diagnosis was myelomalacia in Patient 1 and spinal nephroblastoma in Patient 2. Intraoperative ultrasonography was demonstrated to be suitable for detecting intradural conditions, and, thus, is valuable for increasing the accuracy of biopsies or completeness of resections of intramedullary lesions.

Usefulness of hemilaminectomy for cervical intervertebral disk disease in small dogs.

Hemilaminectomy was performed to treat cervical disc disease in 18 small dogs. Cervical spinal cord compression was characterized by ventral and/or lateral compression on myelograms. The duration of follow-up examinations ranged from 2 to 72 months. The optimal response time after surgery ranged from 2 days to 3 months. The outcome was determined to be excellent if clinical signs resolved and the dog had completely improved. The outcome was determined to be good if the dog improved, but was not clinically normal or if the degree of the owner's satisfaction was insufficient. Fourteen dogs achieved complete neurologic recovery without complications. One dog was initially neurologically worse after surgery, but ultimately improved to normal neurologic status. These outcomes were judged to be excellent. In the remaining 3 dogs, 2 dogs had relapse of neck pain and one dog remained mildly ataxic. These outcomes were judged to be good. These results suggest that hemilaminectomy is an effective option for surgical treatment of spinal cord compression secondary to cervical disc disease in small dogs.

Usefulness of intraoperative ultrasonography for two dogs with spinal disease.

Intraoperative ultrasonography was performed during spinal surgery in two dogs. An extradural lesion was demonstrated by myelography in case 1, and an extradural tumor was found during surgery. Case 2 was diagnosed with a spinal subarachnoid cyst by myelography and magnetic resonance imaging. Ultrasonographically, pathologic conditions of the spinal canal or cord were adequately imaged during surgery in both cases. Intraoperative ultrasonography was a superior method that non-invasively revealed intradural and extradural conditions and thus constitutes a valuable diagnostic mean to ensure safe and precise spinal surgery.

Usefulness of myelography with multiple views in diagnosis of circumferential location of disc material in dogs with thoracolumbar intervertebral disc herniation.

The usefulness of myelography with multiple views (lateral, ventrodorsal, left and right oblique view) in the diagnosis of the exact circumferential location of herniated disc material around the spinal cord in 80 dogs diagnosed with thoracolumbar intervertebral disc herniation at surgery was assessed by comparison of clinical and surgical findings. The circumferential location of the compressing mass was diagnosed in 94% of dogs on myelography. The oblique view was of more benefit than the ventrodorsal view in diagnosing the circumferential distribution of the compressing mass. Only the oblique view contributed to a diagnosis of lateralization of the compressing mass in 45% of dogs. Fourteen percent of dogs had clinical lateralization contralateral to myelographic lateralization. The myelographic localization agreed with the surgical localization in 97% of dogs with regard to the exact location of herniated disc material. The presence of clinical lateralization contralateral to myelographic lateralization and a high proportion of agreement of myelographic and surgical localization documents that myelography with multiple views is useful and essential to accurately determine the circumferential location of disc material around the spinal cord.

Angiotensin converting enzyme and chymase activity in the feline heart and serum.

The feline cardiac and serum angiotensin converting enzyme (ACE) and chymase activities were determined and compared in dogs, and hamsters. In all three species, cardiac chymase activity exceeded ACE activity; however, there were some differences. In cats, left ventricular ACE and chymase activities (0.15 +/- 0.01 and 0.59 +/- 0.1 mU/mg-protein, respectively) were lower than in dogs (0.42 +/- 0.05: p<0.01 and 2.0 +/- 0.4 mU/mg-protein: p<0.01) and hamsters (0.93 +/- 0.06: p<0.001 and 2.1 +/- 0.2 mU/mg-protein: p<0.01); in contrast, serum ACE activities was higher in cats (12.7 +/- 1.0 mU/ml) than in dogs (5.9 +/- 0.6 mU/ml: p<0.001). The relative contribution of chymase (cats: 84.0 +/- 5.1%, dogs: 81.4 +/- 3.4%, and hamsters: 72.6 +/- 5.6 %) to ANG-II formation in the heart was greater than that of ACE in these animals (cats: 10.9 +/- 4.1%, dogs: 11.5 +/- 3.6%, and hamsters: 17.2 +/- 0.8%). These species-specific differences suggest that the efficacy of renin-angiotensin system modulating agents may differ among species.

Bulk cultures of canine peripheral blood lymphocytes with solid phase anti-CD3 antibody and recombinant interleukin-2 for use in immunotherapy.

Interleukin (IL)-2 can induce large numbers of lymphokine-activated killer cells in peripheral blood lymphocytes (PBL), but IL-2 alone cannot induce proliferation of a large number of canine (c) PBL. We used the solid phase anti-CD3 antibody and soluble recombinant (r) IL-2 in order to establish a large scale culture method for cPBL. The number of lymphocytes seeded (3 x 10 (7)) increased to 1 x 10(9) after incubation for 10 days. The phenotype of cultured cPBL cells (after 2 weeks) showed a CD4(+) or CD8(+) predominant cell population. The cultured cell solutions were administered with physiological saline intravenously to each dog. After transfusion of the cultured cells, the cPBL counts, especially the number of CD4(+), CD8(+) and CD4(-)CD8 (-)(DN) cells increased significantly in the recipient dogs. Natural killer (NK) cells, gammadeltaT cells and B cells were considered to be present in the DN cell population. The NK cells and gammadeltaT cells showed no adverse reaction to the transfusion of the activated cPBL. Therefore, it is necessary to recognize the B cells present in the DN cell population by detecting CD21(+) cells. In conclusion, the bulk culture system of cPBL with rIL-2 and solid phase anti-CD3 antibody may be useful for the development of novel immunotherapy in dogs.

Histiocytic ulcerative colitis in a French bulldog.

A 9-month-old French bulldog was referred for signs of chronic large bowel diarrhea. The dog had an increased frequency of defecation, tenesmus and hematochezia. Flexible colonoscopy showed hyperemia, irregularities and ulcerations with multifocal hemorrhages in the mucosa from the descending colon to the proximal rectum. Multiple colonic biopsies were characterized by infiltrations of PAS positive histiocytes in the lamina propria. A diagnosis of histiocytic ulcerative colitis (HUC) was made, and the animal showed only minimal improvement, although it was treated with nutritional and medical therapies. This is the second case of HUC in French bulldog, a breed which has ancestral relations to Boxer dogs.

Comparison of the cardiovascular effects of intracellular cyclic adenosine 3',5'-monophosphate (cAMP)-modulating agents in isoflurane-anesthetized cats.

The inotropic, chronotropic, and vasodilatory effects of five commonly used cyclic adenosine 3',5'-monophosphate (cAMP)-modulating agents were evaluated. Hemodynamic functions were measured continuously in isoflurane-anesthetized cats during infusion of the following: dobutamine (DOB; 2.5, 5 and 10 microg/kg/min; n=8), dopamine (DOP; 1.25, 2.5, 5 and 10 microg/kg/min; n=5), milrinone (MIL; 2.5, 5 and 10 microg/kg/min; n=8), 6-(3-dimethyl-aminopropionyl) forskolin hydrochloride (COL; 0.2, 0.4, 0.8, and 1.6 microg/kg/min; n=7), and bucladesine sodium (BUC; 10, 20, and 40 microg/kg/min; n=9). At the highest infusion rate, DOB and DOP produced the greatest positive inotropic (increase in left ventricular (LV) dP/dt = 89 +/- 4% and 75 +/- 6%, respectively) and chronotropic (increase in heart rate (HR) = 42 +/- 4% and 22 +/- 6%, respectively) effects. MIL and COL produced similar albeit less pronounced positive inotropic (increase in LV dP/dt = 18 +/- 3% and 22 +/- 6%, respectively) and chronotropic (increase in HR = 13 +/- 4% and 21 +/- 4%, respectively) effects. Both also had significant vasodilatory effects (decrease in peripheral resistance (PR) = -30 +/- 2% and -35 +/- 7%, respectively). In contrast, BUC produced only vasodilatation (decrease in PR = -33 +/- 6%). Hence, MIL, COL, and BUC had significant vasodilatory effects and less-pronounced inotropic effects than the catecholamines DOB and DOP. The vasodilatory effects of non-catecholamine drugs for treatment of congestive heart failure should translate into beneficial decreases in both pre-load and after-load. In contrast, the strong inotropic effects of DOB and DOP should be beneficial in the treatment of acute heart failure and anesthetic crisis.

Canine serum alkaline phosphatase isoenzymes detected by polyacrylamide gel disk electrophoresis.

Serum alkaline phosphatase (ALP) isoenzymes were studied in normal dogs using a commercially available polyacrylamide gel disk electrophoresis kit (PAG/disk kit). Serum samples taken from the dogs were incubated with neuraminidase, after which most showed ALP isoenzymes as two characteristic stained bands. To determine the origin of each band, ALP isoenzymes of serum and tissue extracts (liver, intestine and bone) were characterized by heating, wheat germ agglutinin (WGA) and levamisole treatments. The results suggested that the band detected on the anode was liver ALP (LALP) and that the band detected on the cathode represented bone ALP (BALP), and both were corticosteroid-induced ALP (CALP). The percentage of each ALP isoenzyme to total ALP activity was estimated by densitometry. The percentage of BALP was the highest in young dogs (age<1 year, 64.7% ), and this value decreased with age. In contrast, the percentage of LALP in young dogs (22.2%) was much lower than that in middle-aged dogs (ages 1 year to 7 years, 59.3%) and old dogs (ages>7 years, 50.4%). The present results suggested that a commercially available PAG/disk kit is capable of detecting three serum ALP isoenzymes in dogs, and further that it may have clinical applications in the evaluation of ALP isoenzymes in veterinary medicine.