Nancy Stedman

Tumor necrosis factor α blockade exacerbates murine psoriasis‐like disease by enhancing Th17 function and decreasing expansion of Treg cells

OBJECTIVE Patients with psoriasis and psoriatic arthritis respond well to tumor necrosis factor alpha (TNFalpha) blockers in general; however, there is now mounting evidence that a small cohort of patients with rheumatoid arthritis who receive TNFalpha blockers develop psoriasis. This study was undertaken to explore the mechanisms underlying TNFalpha blockade-induced exacerbation of skin inflammation in murine psoriasis-like skin disease. METHODS Skin inflammation was induced in BALB/c scid/scid mice after they received CD4+CD45RB(high)CD25- (naive CD4) T cells from donor mice. These mice were treated with either anti-interleukin-12 (anti-IL-12)/23p40 antibody or murine TNFRII-Fc fusion protein and were examined for signs of disease, including histologic features, various cytokine levels in the serum, and cytokine or FoxP3 transcripts in the affected skin and draining lymph node (LN) cells. In a separate study, naive CD4+ T cells were differentiated into Th1 or Th17 lineages with anti-CD3/28 magnetic beads and appropriate cytokines in the presence or absence of TNFalpha. Cytokine gene expression from these differentiated cells was also determined. RESULTS Neutralization of TNFalpha exacerbated skin inflammation and markedly enhanced the expression of the proinflammatory cytokines IL-1beta, IL-6, IL-17, IL-21, and IL-22 but suppressed FoxP3 expression in the skin and reduced the number of FoxP3-positive Treg cells in the draining LNs. TNFalpha also demonstrated a divergent role during priming and reactivation of naive T cells. CONCLUSION These results reveal a novel immunoregulatory role of TNFalpha on Th17 and Treg cells in some individuals, which may account for the exacerbation of skin inflammation in some patients who receive anti-TNF treatments.

Variation among Pathologists in the Histologic Grading of Canine Cutaneous Mast Cell Tumors with Uniform Use of a Single Grading Reference

Ten veterinary pathologists independently assigned histologic grades to the same 60 canine cutaneous mast cell tumors using the Patnaik classifications. The degree of agreement in grading among the pathologists was compared with the degree of agreement among the same pathologists in a previous study, in which each pathologist used the reference for grading that he/she uses routinely. Mean agreement improved significantly from 50.3% to 62.1% with uniform use of the Patnaik classifications (P = 0.00001), suggesting that there is value in uniform application of a single grading scheme for canine cutaneous mast cell tumors. Agreement among pathologists was still not 100%, suggesting that a more objective grading scheme should be developed and that other histologic indicators of prognosis should be investigated.

Variation among pathologists in histologic grading of canine cutaneous mast cell tumors.

Ten veterinary pathologists at 1 veterinary institution independently assigned histologic grades to the same 60 canine cutaneous mast cell tumors (MCTs). There was significant variation among pathologists in grading the MCTs (P < 0.001). The probability of assigning a low grade was significantly higher for the pathologists in this study who use a published reference for histologic grading of canine cutaneous MCTs that allows subcutaneous MCTs or MCTs with mitotic figures to be included in the low-grade category (P < 0.0001 and P < 0.0001, respectively).

Pharmacokinetics of meloxicam following intravenous and oral administration in green iguanas (Iguana iguana)

OBJECTIVE To determine pharmacokinetics of meloxicam in healthy green iguanas following PO and IV administration and assess potential toxicity. ANIMALS 21 healthy green iguanas (Iguana iguana). PROCEDURES To assess pharmacokinetics, 13 iguanas were administered a single dose (0.2 mg/kg) of meloxicam PO and, 14 days later, the same dose IV. To assess potential toxicity, 4 iguanas were given meloxicam at a dosage of 1 or 5 mg/kg, PO, every 24 hours for 12 days, and results of histologic examination were compared with results for another 4 iguanas given a single dose of meloxicam (0.2 mg/kg). RESULTS There were no significant differences between PO and IV administration with regard to terminal half-life (mean ± SD, 12.96 ± 8.05 hours and 9.93 ± 4.92 hours, respectively), mean area under the curve to the last measured concentration (5.08 ± 1.62 μg•h/mL and 5.83 ± 2.49 μg•h/mL), volume of distribution (745 ± 475 mL/kg and 487 ± 266 mL/kg), or clearance (40.17 ± 10.35 mL/kg/h and 37.17 ± 16.08 mL/kg/h). Maximum plasma concentration was significantly greater following IV (0.63 ± 0.17 μg/mL) versus PO (0.19 ± 0.07 μg/mL) administration. Time from administration to maximum plasma concentration and mean residence time were significantly longer following PO versus IV administration. Daily administration of high doses (1 or 5 mg/kg) for 12 days did not induce any histologic changes in gastric, hepatic, or renal tissues. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that administration of meloxicam at a dose of 0.2 mg/kg IV or PO in green iguanas would result in plasma concentrations > 0.1 μg/mL for approximately 24 hours.

RENAL EVALUATION IN THE HEALTHY GREEN IGUANA (IGUANA IGUANA): ASSESSMENT OF PLASMA BIOCHEMISTRY, GLOMERULAR FILTRATION RATE, AND ENDOSCOPIC BIOPSY

Abstract Plasma biochemistry, iohexol clearance, endoscopic renal evaluation, and biopsy were performed in 23 clinically healthy 2-yr-old green iguanas (Iguana iguana). Mean (±SD) values for packed cell volume (30 ± 3%), total protein (62 ± 7 g/L, 6.2 ± 0.7 g/dl), albumin (25 ± 2 g/L, 2.5 ± 0.2 g/dl), globulin (37 ± 6 g/L, 3.7 ± 0.6 g/ dl), total calcium (3.0 ± 0.2 mmol/L, 12.0 ± 0.7 mg/dl), ionized calcium (1.38 ± 0.1 mmol/L), phosphorus (1.32 ± 0.28 mmol/L, 4.1 ± 0.9 mg/dl), uric acid (222 ± 100 μmol/L, 3.8 ± 1.7 mg/dl), sodium (148 ± 3 mmol/L or mEq/ L), and potassium (2.6 ± 0.4 mmol/L or mEq/L) were considered within normal limits. Values for urea were low (<1.4 mmol/L, <4 mg/dl) with 70% of samples below the detectable analyzer range. After the i.v. injection of 75 mg/ kg iohexol into the caudal (ventral coccygeal or tail) vein, serial blood collections were performed over 32 hr. Iohexol assays by high-performance liquid chromatography produced plasma iohexol clearance graphs for each lizard. A three-compartment model was used to fit area under the curve values and to obtain the glomerular filtration rate (GFR) using regression analysis. The mean GFR (SD) was 16.56 ± 3.90 ml/kg/hr, with a 95% confidence interval of 14.78–18.34 ml/kg/hr. Bilateral endoscopic renal evaluation and biopsy provided tissue samples of excellent diagnostic quality, which correlated with tissue harvested at necropsy and evaluated histologically. None of the 23 animals demonstrated any adverse effects of iohexol clearance or endoscopy. Recommended diagnostics for the evaluation of renal function and disease in the green iguana include plasma biochemical profiles, iohexol clearance, endoscopic examination, and renal biopsy.

A Survey of Selected Avian Pathogens of Backyard Poultry in Northwestern Ecuador

Abstract As part of a larger ecologic research project and to collect disease prevalence information on backyard chicken flocks in northwestern Ecuador, 100 randomly selected birds from 10 flocks were examined, and blood, fecal, and ectoparasite samples were collected. The owners of the flocks were surveyed regarding flock management and disease history. Mean flock size was 20 birds (range, 1–75), and birds were kept for eggs and meat for either domestic consumption or local sale. Vaccination rates were low, with most owners (8 of 10) not vaccinating at all and some (2 of 10) vaccinating with one product either sporadically (1 of 10) or annually (1 of 10). None of the owners treated their chickens for parasites. Mortality rates of offspring were reported as high as 50% (range, 35%–50%) per flock. Deaths were associated with diseases described by owners as causing neurologic signs, sudden death, or respiratory problems. In addition, owners described epizootics of wartlike seasonal skin lesions, presumably but not confirmed as avian pox. Results of commercial enzyme-linked immunosorbent assays on serum samples showed that birds had antibodies against infectious bursal disease virus (100%), Newcastle disease virus (97%), avian encephalomyelitis virus (92%), chicken anemia virus (90%), infectious bronchitis virus (85%), Mycoplasma gallisepticum (73%), and Mycoplasma synoviae (68%). Although 11% of birds showed the presence of antibodies for avian influenza, antibody levels were low in all but 4 birds. Most birds (90%) had feather mite infestations. Results of necropsy and fecal examinations found low levels of internal parasitism, with cestodes and ascarids identified as the most prevalent endoparasites. Ectoparasites identified were Dermanyssus gallinae and Ornithonyssus bursa. The poultry diseases to which sampled chickens had been exposed are likely the cause of the high mortality rate reported by flock owners. In these backyard poultry flocks in Ecuador, preventive medicine protocols that provide realistic cost-benefit advantages should be implemented. Because wild birds are susceptible to some poultry diseases, free-roaming chickens might be potential vectors of pathogens that could affect wild birds.

Uterine Leiomyomas in Two Vietnamese Pot-bellied Pigs (Sus scrofa):

Two Vietnamese pot-bellied pigs (Sus scrofa) were euthanatized after they developed abdominal distension. Necropsy of both pigs revealed large myometrial neoplasms and cystic endometrial hyperplasia. Multiple discrete smaller myometrial neoplasms were also observed in one pig; however, distant metastases were not observed in either animal. The tumors were diagnosed as leiomyomas on the basis of histologic examination and immunohistochemistry. This is the first detailed report of uterine leiomyomas in swine, and it is suggested that this diagnosis may become more common as more aging pigs are examined.

Comparison and verification of quantitative competitive reverse transcription polymerase chain reaction (QC-RT-PCR) and real time RT-PCR for avian leukosis virus subgroup J

Avian leukosis virus subgroup J (ALV-J) infections cause significant economic losses because of increased mortality, tumor production, decreased production, and cost for eradication. Current quantification methods for ALV-J expressed by TCID(50) are difficult to determine because of the lack of cytopathic effect in cell cultures and non-specificity of currently available antigen-capture ELISA tests. In this study, a one-tube fluorescent probe based real time RT-PCR method was developed for quantification of ALV-J and compared with available quantification methods. Cell lysates with different TCID(50)s determined by cell culture and antigen capture ELISA (ag-ELISA) were used for one-tube real time RT-PCR using fluorogenic probe and quantitative competitive RT-PCR (QC-RT-PCR). The results of QC-RT-PCR and real time RT-PCR were highly correlated to the TCID(50)s determined by conventional culture methods. They were also very specific, sensitive, easy to perform, reproducible, and rapid compared with conventional methods. These RT-PCR based quantification methods of ALV-J viral RNA will be useful for virological and pathogenesis studies.

INTRAVASCULAR CARTILAGINOUS EMBOLI IN THE SPINAL CORD OF TURKEYS

A flock of 15-wk-old tom turkeys experienced an acute onset of paresis and ataxia in 75% of the birds after handling. Cartilaginous emboli were found in the spinal cord vasculature from one of five turkeys at this initial presentation. Most of the flock recovered within 6 days, but 3% remained paretic. Myelomalacia was present in three turkeys that failed to recover. Two of these turkeys had cartilaginous and osseous emboli within the medullary spaces of the vertebral bodies, internal vertebral venous sinuses, and spinal cord. The third turkey had vascular and spinal cord necrosis consistent with thrombosis and resultant ischemia. These changes suggest that turkeys may be susceptible to a syndrome analogous to fibrocartilaginous embolism of the spinal cord in mammals. The articular cartilage of the vertebral body endplate may be the source of the emboli. The turkeys with emboli had articular cartilage defects consisting of matrix eosinophilia, chondrocyte loss, multicellular cluster formation, cartilage detachment, and cartilage clefts. Cartilaginous emboli in the spinal cord should be considered as a potential cause for acute paresis and ataxia, especially in flocks with preexisting abnormalities of the vertebral articular cartilage surfaces.

Localization of Avian Leukosis Virus Subgroup J in Naturally Infected Chickens by RNA In Situ Hybridization

The novel subgroup J of avian leukosis virus (ALV-J) has emerged as a significant cause of myeloid neoplasia and weight suppression in broiler chickens. We investigated viral tropism using RNA in situ hybridization (ISH) in naturally infected chickens. Formalin-fixed tissues were collected from 12-day-old embryos (seven infected, two control) and from 0-week-old (four infected, one control), 3-week-old (five infected, one control), 6-week-old (five infected, one control), and 9-week-old (10 infected, two control) chickens naturally infected with ALV-J in ovo. A 636-base antisense riboprobe complementary to the 3′ and 5′ ends of the pol and env viral genes, respectively, was constructed. Strong positive staining was present in cardiac myocytes, Purkinje fibers, vascular and pulmonary smooth muscle, renal glomeruli, distal tubules, and pituitary glands. Light staining was present in gastrointestinal smooth muscle, thyroid and adrenal glands, and follicular medullae in the cloacal bursa. Staining was not present in any hematopoietic precursors. Tissues from newly hatched chicks exhibited the strongest and most consistent staining, whereas staining in embryos was minimal. RNA ISH confirmed the presence of ALV-J-specific nucleic acid within cytoplasmic inclusions in cardiac myocytes, Purkinje fibers, pituitary glands, and renal glomeruli. Viral tropism for cardiac myocytes and Purkinje fibers may relate pathogenetically to the cardiomyopathy and congestive heart failure described in index chicken flocks infected with ALV-J. Viral tropism for endocrine organs may relate pathogenetically to the weight suppression associated with infection.