[ Bone and cartilage destruction in RA and its intervention. Disease-modifying antirheumatic drugs]

The primary goal in the treatment of rheumatoid arthritis (RA) is to maintain good quality of life by preventing joint destruction and avoiding disability. For this purpose, all patients with the diagnosis of RA should be treated by disease-modifying antirheumatic drugs (DMARDs) including biologic DMARDs and non-biologic DMARDs. All DMARDs are expected to prevent the progression of bone and cartilage destruction of RA patients from the results of in vitro research, and prevention of joint destruction is confirmed in vivo in all biologic DMARDs, but not in all non-biologic DMARDs. In this chapter, we would like to review the results of basic researches and clinical studies to demonstrate the prevention of joint destruction by non-biologic DMARDs that have been frequently used I daily practice.

Characterization of glycans in the developmental stages of Myxobolus cerebralis (Myxozoa), the causative agent of whirling disease

Glycans and sugar-binding molecules (lectins) form an interactive recognition system, which may enable parasitic organisms to adhere to host cells and migrate into target tissues. The aim of the present study was to analyse surface-associated glycans in the developmental stages of Myxobolus cerebralis (Hofer), the causative agent of whirling disease. A panel of biotin-labelled plant lectins was used to detect a broad spectrum of glycan motifs with high specificity. Binding sites were detected histochemically in the tissue sections of infected rainbow trout, Oncorhynchus mykiss (Walbaum), and infected Tubifex tubifex (Müller), and were characterized by light, fluorescence and transmission electron microscopy. With mannose-specific lectins [Lens culinaris agglutinin, Pisum sativum agglutinin, Canavalia ensiformis agglutinin (LCA, PSA, CanA)] mannose-containing glycans were detected in all the developmental stages and host tissues. No binding sites for galactose-specific lectins were present in M. cerebralis spores but reactivity with host tissues occurred. Diversity in glycans was detected by N-acetyl-D-galactosamine-specific lectins in sporoplasm cells of M. cerebralis and triactinomyxon spores. In the group of lectins with monosaccharide-specificity for N-acetyl-D-glucosamine (GlcNAc), the reactivity of Datura stramonium agglutinin (DSA), Lycopersicon esculentum agglutinin (LEA) and Solanum tuberosum agglutinin (STA) was restricted to polar capsules whereas Griffonia simplicifolia agglutinin II (GSA II) also bound to sporoplasm cells of stages in the fish host but not in those present in infected T. tubifex. Moreover, Triticum vulgaris (wheat germ) agglutinin (WGA) and succinylated WGA indicated the presence of N-acetyl-D-glucosamine polymers in polar capsules. No specificity for spores was observed concerning 'bisected'N-glycans and no reactivity in parasitic stages was observed with the fucose-binding lectin Ulex europaeus agglutinin (UEA) I, Sambucus nigra agglutinin (SNA) (specific for alpha2,6-sialylated glycans) and Maackia amurensis agglutinin (MAAI) (specific for alpha2,3-sialylated glycans). Arachis hypogaea (peanut) agglutinin (PNA), Erythrina cristagalli agglutinin (ECA), GSA I, Sophora japonica agglutinin (SJA), Dolichos biflorus agglutinin (DBA) and GSA II detected reactive sites solely confined to the developmental stages of M. cerebralis and were not reactive in the fish host. These parasite-specific glycans may play a role in the adhesion process of the parasite to fish epidermis prior to infection, but may provide protection to the host by activating the complement system, or stimulating an adaptive immune response as putative antigens.

Pseudomonas aeruginosa otochondritis complicating localized cutaneous leishmaniasis: prevention of mutilation by early antibiotic therapy

A patient with an ulcerated cutaneous leishmaniasis of the pinna had suppurative otochondritis after a first unsuccessful course of treatment with meglumine antimoniate. Although the Leishmania ulceration healed after a second course of meglumine antimoniate, and despite three oral dicloxacillin or pristinamycin courses, the otochondritis extended and an abscess developed. Pus from the abscess revealed a pure culture of Pseudomonas aeruginosa. Five days of oral ciprofloxacin plus rifampin led to a marked improvement. The P. aeruginosa isolate was sensitive to ciprofloxacin but fully resistant to rifampin. Healing with minimal mutilation was obtained at the end of a six-week course of multiple antibiotic therapy. Pseudomonas aeruginosa otochondritis was a co-factor of cartilage mutilation in this patient. Thus, infection with P. aeruginosa should be promptly treated when present in tender cutaneous or mucosal leishmaniasis lesions near cartilaginous areas.

Trypanosoma cruzi: experimental parasitism of bone and cartilage

Trypanosoma cruzi causes Chagas' disease, a systemic infection that affects cells of meso-, endo-, and ectodermic origin. However, as far as we know, the presence of T. cruzi stages in bone has not been reported previously, and it has scarcely been investigated in cartilage. We inoculated 7- and 20-day-old (8 and 15 g) NMRI albino mice i.p. with metacyclic trypomastigotes from Rhodnius prolixus used for xenodiagnosis of mice previously infected with mammalian, human, and triatomines isolates, characterized by randomly amplified polymorphic DNA as zymodeme 1 (equivalent to T. cruzi I). Tissular parasitism (quantified according to the number of pseudocysts/50 fields 400x) showed amastigotes, intermediate forms, or trypomastigotes in sternum chondroblasts, osteoblasts, macrophages, and fibroblasts; chondrocyte and osteocyte invasion was rare. All isolates parasitized bone marrow macrophages, with few amastigotes. We observed marked associated myotropism, with or without inflammatory infiltration; there were small numbers of intensely parasitized mononuclear cells in perichondrium and periosteum. We discuss the results in relation to the marked differences of the T. cruzi tropism toward the different types of sternum cells, and, additionally, we outline the possibility of transmitting parasitized bone marrow through transplants. The fact of finding parasite stages in sternum bone and cartilage may be considered important due to the studies on Chagas' disease paleoparasitology that are based on histological and molecular analysis.

Immunostaining of spores and plasmodia of disparate myxozoan genera with comments on the properties of the sporular mucus envelope

Species of the phylum Myxozoa are common parasites of fish and can cause severe losses in cultured species. Although a number of myxozoan life-cycles have now been elucidated, little is known about the biology of these organisms in the fish host. Monoclonal antibody B4 raised to the myxozoanTetracapsuloides bryosalmonaehas been previously noted to react with a number of species infecting fish kidney. We present the results of a survey of 55 myxosporean species that determined that this antibody detects an antigen on the spore surface of 33 of these species in the generaMyxobolus,SphaerosporaandThelohanellus. However, there appears to be no clear relationship between those spores that contain the MAb B4 reactive antigen and the host or organ in which they are detected. The antigen appears to be synthesized in the plasmodial cytoplasm and is intimately associated with the surface of the spore capsules and, where present, the mucus envelope. The nature of this envelope is further discussed in relation to its formation and distinctive properties.

Histologic study of head cartilage degeneration in rainbow trout (Oncorhynchus mykiss) infected with the parasite Myxobolus cerebralis

A light microscopy study of head cartilage tissue in rainbow trout alevins (Oncorhynchus mykiss) infected with the parasite Myxobolus cerebralis showed that, regardless of the presence or absence of whirling disease symptoms such as black tail and whirling swimming due to altered tail and spine morphology, some fish presented large amounts of spores lodged in the head after three months of infection. The spores were located in regions where the cartilage was extensively destroyed.

Myxobolus intrachondrealis sp. n. (Myxosporea: Myxobolidae), a parasite of the gill cartilage of the common carp, Cyprinus carpio

A species not identifiable with any of the about 23 Myxobolus species recorded from the common carp so far, was detected in the gills of one- and two-summer-old specimens of the common carp ((Cyprinus carpio L.) cultured in pond farms in Hungary. The strictly tissue-specific plasmodia of the parasite were located, surrounded by hyaline cartilage cells, in the chondrous substance of the terminal parts of the gill arches and in the cartilage structure ventrally connecting the gill arches. The spores of the parasite described as Myxobolus intrachondrealis sp. n. developed in globular or ellipsoidal plasmodia measuring 300-600 microm. By their elongated ellipsoidal shape and similarly elongated polar capsules the spores were well distinguishable from the hitherto described Myxobolus species parasitic in the common carp and also from the cartilage-parasitic Myxobolus species of other fishes.

A trematode metacercaria causing gill cartilage proliferation in steelhead trout from Oregon

Gills of steelhead trout (Oncorhynchus mykiss) held in liveboxes to detect the presence of pathogens in the Willamette River (Oregon, USA) became heavily infected with trematode metacercariae. The metacercariae encysted adjacent to the cartilaginous rods of gill filaments and elicited a host response of cartilage proliferation from the perichondrium. Although some hyperplasia of gill epithelium and fusion of lamellae was apparent, the extent of damage to the respiratory surface was apparently insufficient to cause trout mortality. Morphological characteristics of the metacercariae did not allow precise identification, but they suggested affinities to either the Heterophyidae or Cryptogonimidae. Some heterophyids are known to cause proliferation of cartilage in fish gills, while cryptogonimids are not. This is the first report of trematode induced gill cartilage proliferation in steelhead trout.

Distribution of Myxobolus scleroperca (Myxobolidae: Myxosporea) in yellow perch (Perca flavescens) in the Great Lakes

Myxobolus scleroperca infected the sclerotic cartilage of 26 of 100 yellow perch (Perca flavescens) examined in August-September 1991 from the Indiana waters of southern Lake Michigan. The mean lengths of infected and uninfected fish were 171 mm and 148 mm, respectively. A significantly higher percentage of female fish were infected than male because more larger females were examined than males. Perch less than 94 mm were not infected, indicating that the parasite is not evenly distributed in the host population, preferring larger (older) fish. An alternative explanation that should be considered is that young fish die from this infection. Yellow perch collected from eastern Lake Michigan in 1990 and from Saginaw Bay, Lake Huron in 1991 were not infected with M. scleroperca, indicating that the parasite has a patchy distribution among perch populations of the Great Lakes.

Transmission of salmonid whirling disease by birds fed trout infected with Myxosoma cerebralis

Mallard ducks, Anas platyrhynchos and a black crested night heron, Nycticorax nycticorax were fed trout infected with Myxosoma cerebralis (HOFER) in 2 separate experiments. Feces from the birds were deposited in troughs containing M. cerebralis-free mud as well as in 1 trough without mud. Spore suspensions were also added directly to mud in 1 trough and to another without mud. Susceptible rainbow trout, Salmo gairdneri, developed whirling disease in all troughs containing mud contaminated with M. cerebralis but remained free of infection when exposed to M. cerebralis in troughs without mud. This demonstrates the possibility of bird transmission of the organism causing whirling disease to previously non-contaminated waters.