J. N. Mills

Antagonism of the IL-6 cytokine subfamily — a potential strategy for more effective therapy in rheumatoid arthritis

Abstract. Pro-inflammatory cytokines, some of which have the capacity to modulate cartilage and bone metabolism, are important mediators of the frequently sustained and destructive inflammation that characterises rheumatoid arthritis (RA). Tumour necrosis factor alpha (TNFα) and interleukin-1 (IL-1) have been studied extensively in this regard. That these proteins are important is no longer in doubt following the demonstration that the IL-1 receptor antagonist and neutralising antibodies directed against TNFα are clinically effective. Recent studies suggest that interleukin-6 (IL-6) and other members of the IL-6 cytokine subfamily are also potentially important cytokines in the pathogenesis of RA. The recognition of shared molecular subunits in the receptors for these cytokines raises the possibility that components of these receptors or their derivatives, either alone or in combination, may be useful for antagonising members of the IL-6 cytokine subfamily. Effective antagonism could be therapeutically beneficial in respect to attenuating inflammation and protecting critically important chondral and skeletal tissue. In this review the rationale and possible strategies for such antagonism are discussed.

The First Complete Papillomavirus Genome Characterized from a Marsupial Host: a Novel Isolate from Bettongia penicillata

ABSTRACT The first fully sequenced papillomavirus (PV) of marsupials, tentatively named Bettongia penicillata papillomavirus type 1 (BpPV1), was detected in papillomas from a woylie (Bettongia penicillata ogilbyi). The circular, double-stranded DNA genome contains 7,737 bp and encodes 7 open reading frames (ORFs), E6, E7, E1, E2, E4, L2, and L1, in typical PV conformation. BpPV1 is a close-to-root PV with L1 and L2 ORFs most similar to European hedgehog PV and bandicoot papillomatosis carcinomatosis virus types 1 and 2 (BPCV1 and -2). It appears that the BPCVs arose by recombination between an ancient PV and an ancient polyomavirus more than 10 million years ago.

Oncostatin M induces leukocyte infiltration and cartilage proteoglycan degradation in vivo in goat joints

OBJECTIVE To evaluate the effect of intraarticular injections of recombinant human oncostatin M (rHuOSM) in the goat joint. METHODS One milliliter of endotoxin-free normal saline (vehicle) containing either 40 ng, 200 ng, or 1,000 ng of rHuOSM was injected into the right radiocarpal joints (RCJs) of 12 male angora goats, while the left RCJs were injected with an equivalent volume of vehicle alone. In subsequent studies, the right and left RCJs of 8 male angora goats were injected with 200 ng of rHuOSM, and 1 hour later, the right RCJs were injected with either 5 microg of recombinant murine leukemia inhibitory factor binding protein (rMuLBP) or 1 mg of recombinant human interleukin-1 receptor antagonist (rHuIL-1Ra) in 1 ml of vehicle, while the left RCJs received 1 ml of vehicle alone. Goat joints were examined for clinical features of inflammation, and synovial fluid (SF) was aspirated on day 0 (before injection) and at days 2 and 6 postinjection. RESULTS Injections of rHuOSM stimulated dose-dependent increases in the carpal:metacarpal ratio, SF volume, and SF leukocyte numbers, and stimulated dose-dependent decreases in the cartilage proteoglycan (PG) content ex vivo and PG synthesis. No significant changes were observed in the control joints that received saline alone, or between RCJs that were injected with 200 ng rHuOSM followed by 5 microg rMuLBP and RCJs that were injected with 200 ng of rHuOSM alone, except in respect to synovial fluid keratan sulfate concentrations, where a modest statistically significant reduction was observed in the joints injected with the combination of rHuOSM and rMuLPB. In contrast, RCJs injected with 200 ng rHuOSM followed by 1 mg of rHuIL-1Ra had significantly lower SF volumes (P<0.0001) and a significantly higher rate of ex vivo PG synthesis (P<0.0001). CONCLUSION These results indicate that rHuOSM stimulates inflammation and modulates cartilage PG metabolism in vivo. Some of the effects of rHuOSM in vivo appear to be due, in part, to elaboration of IL-1. Even at very high doses, however, the rHuIL-1Ra did not attenuate OSM-mediated cartilage PG resorption. Thus, OSM has the potential to contribute to synovitis in vivo and can stimulate cartilage PG resorption in vivo, independent of IL-1.

Replication of four antigenic types of avian reovirus in subpopulations of chicken leukocytes

The replication of four antigenic types of avian reovirus in various subpopulations of avian leukocytes was investigated. Virus replication was detected in infected cells by immunofluorescence using a monoclonal antibody against a virion protein and by electron microscopy. All four types of reovirus replicated in cultured, adherent mononuclear cells of both bone marrow and peripheral blood origin causing lysis and fusion of the infected cells. Some evidence of strain variation in the capacity of avian reoviruses to replicate in these cells was detected. Avian reovirus did not replicate in heterophils or thrombocytes of peripheral blood origin or in bursa or thymus-derived lymphocytes.

Pathophysiology of Mesocestoides corti infection in the mouse.

Liver histology and serum enzyme and protein changes were studies in two strains of mice showing different initial susceptibilities to infection with Mesocestoides corti. The results show an increase in ALT and AST levels during the period of invasion and proliferation in the liver and a decrease in the levels of these two enzymes following encapsulation of the parasite in the liver and liver regeneration. A progressive loss of albumin was accompanied by increases in the levels of the beta- and gamma-globulins. These changes are discussed in the light of our knowledge of the effects of this parasite upon its host.

The proinflammatory and chondral activities of leukemia inhibitory factor in goat joints are partially a function of interleukin-1

We wished to determine if the effects of injected recombinant human leukemia inhibitory factor (LIF) are a function of endogenous goat interleukin-1 (IL-1) production and, conversely, if the effects of injected recombinant human IL-1 are a function of endogenous LIF production in goat radiocarpal joints (RCJ). In preliminary experiments, murine LIF binding protein (MuLBP) and recombinant HuIL-1RA were found to independently attenuate the cartilage proteoglycan resorbing activity of goat synovial membrane-conditioned medium (GSMCM), implying activity against goat LIF and goat IL-1, respectively. The present study shows that the proinflammatory and chondral actions of rHuLIF in goat RCJ are partially attenuated by rHuIL-1RA. This implies that a small but important component of the in vivo activity of rHuLIF is a result of IL-1 production in the synovial joint. With the exception of proteoglycan synthesis, the absence of significant effects by MuLBP on the actions of rHuIL-1alpha in goat RCJ suggests that the proinflammatory and chondral effects of IL-1alpha in vivo are probably not mediated by LIF.

Separation of phagocytic leukocytes from the peripheral blood of chickens

Phagocytic leukocytes were separated from the peripheral blood of chickens using a one-step Percoll density gradient technique. Heterophils recovered from two fractions of the gradient were of 96.9 to 99.8% purity and were fully viable and functional, as demonstrated by their capacity to phagocytose latex beads and staphylococci. Adherent mononuclear cells were cultured from specific gradient fractions and shown to phagocytose staphylococci.

Lymph Node Cytology

In clinical practice, animals with lymphadenopathy are eminently suitable candidates for cytology sample collection by FNAB from several enlarged nodes; or, if surgical biopsies are made, imprint smears from the tissue may yield diagnostically useful information to supplement the histological findings. Cytology may reveal the lesion to be reactive, inflammatory, or neoplastic. Cytologically, reactive nodes will contain increased numbers of plasma cells, possibly with some inflammatory cells, along with the resident lymphoid population. If inflammation is present, neutrophils and macrophages also will be found and the type of inflammation may be classified. Any infectious agent such as fungal hyphae, yeasts, bacteria, and protozoa also may be demonstrated. Aspirates may be cultured directly onto blood agar plates or transported in nutrient broth for culture at a referral laboratory. In chronic dermatopathic nodes, a mixed inflammatory cell infiltrate is expected, and in pruritic skin disorders, eosinophils usually are plentiful in node aspirates. Increased numbers of eosinophils also may be found in dogs that are microfilaremic with heartworm infection. Background debris of hemosiderin and melanin pigment and other fine particles may occur in some chronic inflammatory lymphadenopathies. Metastatic lesions are identified by the presence of foreign neoplastic cells, but this diagnosis may be missed in early metastatic spread or if the aspirate is not sufficiently cellular. A cytological guide to the classification of the more common diffuse canine lymphomas is provided but full characterization of the lymphoma type may require histology and immunocytochemistry. In practice, a simple differential Romanowsky stain such as Diff Quik is suitable for most purposes. Supplementary stains using 1 per cent toluidine blue may increase the detection of mast cells. Aspirates also may be transferred into suitable media for transport to a referral diagnostic laboratory for cytocentrifugation or further tests such as electron microscopy, immunocytochemistry, flow cytometry, and culture. Although definitive diagnosis by histopathology and other tests still may be required, in many routine cases, diagnoses can be achieved expediently in clinical practice by aspiration cytology.

Basophilic Enterocolitis in a Horse

phoid tumors are relatively common neoplasms in most domestic animals.’ Those classified as lymphosarcoma are much more frequent than lymphocytic leukemias. This is the first reported case of lymphocytic leukemia in the ferret. A one-year-old male ferret was housed in an outdoor Wire mesh enclosure with a female ferret. The ferrets had been in good health until the male was found dead unexpectedly one morning. On gross examination, the mesenteric lymph nodes, anterior thoracic lymph nodes, and spleen were enlarged. The liver was swollen and pale. Histological examination revealed a marked leukemic infiltration in all organs examined. The tumor cells were pleomorphic round cells with round or indented nuclei containing clumped chromatin and one or more prominent nucleoli. Cytoplasm was scant, and mitotic figures were rare. The architecture of the lymph nodes was effaced and the leukemic cells had invaded the capsule and perinodal fat. The hepatic sinusoids were flooded with tumor cells resulting in extensive atrophy of the hepatic cords. (figs. 1,2) A diagnosis of a welldifferentiated lymphocytic leukemia was made. Serum from this ferret was not available, however, the female ferret housed in the same cage was bled and found to be FeLV negative. References

Stilboestrol toxicity in a dog

A case of stilboestrol toxicity is described in a dog which was treated for prostatic hyperplasia with stilboestrol dipropionate (10 mg) daily for 5 days. An initial anaemia and thrombocytopaenia of 19,500/microliters was recorded on day 11, and a severe leukocytosis of 125,300/microliters on day 15 was followed by a precipitous drop to 8,400/microliters on day 21. The dog received antibiotic treatment for concurrent peritonitis and prostatitis/cystitis between days 7 and 15. The dog died on day 41 with marrow aplasia.