Trypanosoma cruzi is lysed by coelomic cytolytic factor-1, an invertebrate analogue of tumor necrosis factor, and induces phenoloxidase activity in the coelomic fluid of Eisenia foetida foetida.

A cytolytic protein named Coelomic Cytolytic Factor-1 (CCF-1) was isolated from the coelomic fluid of the earthworm Eisenia foetida foetida. Despite the absence of any gene homology, CCF-1 showed functional analogy with the mammalian cytokine tumour necrosis factor (TNF), particularly based on similar lectin-like activity. Indeed, both CCF-1 and TNF recognise N,N'-diacetylchitobiose and exert lytic activity on African Trypanosoma brucei brucei. In this report, we show that South-American Trypanosoma cruzi trypomastigotes, but not epimastigotes, were lysed by earthworm coelomic fluid or purified CCF-1. However, T. cruzi was less susceptible to lysis than T. brucei brucei. This lytic effect of coelomic fluid and CCF-1 on T. cruzi trypomastigotes was partially inhibited in the presence of anti-CCF-1 monoclonal antibody, antibody neutralising the lectin-like activity of TNF or N,N'-diacetylchitobiose. In contrast, this lytic effect was completely inhibited when using T. b. brucei. In addition, T. cruzi components, upon recognition by CCF-1 in E. f. foetida coelomic fluid, triggered the prophenoloxidase cascade, an invertebrate defence mechanism. These results further extend the functional analogies of CCF-1 and TNF, suggesting that both molecules share a similar lectin-like activity that has been conserved as an innate recognition mechanism in invertebrates and vertebrates. They also establish a link between stercorarian (T. cruzi) and salivarian (T. brucei) trypanosomatids having divergent phylogenetic origins and patterns of evolution, but possessing closely related cell surface sugar moieties.     

Comparison of caprine,human and bovine strains of respiratory syncytial virus

Summary A new continuous ovine kidney cell line allowing the growth of caprine, human and bovine respiratory syncytial virus was used to minimize host cell related variations for the direct comparison of the viral ultrastructures, serological relationships and structural protein profiles. Results show that all three strains are closely related although a closer relationship was found between bovine and caprine RS.     

Rheumatoid factor on a daily basis

Rheumatoid factors (RF), which are antibodies (Ab) with specificity directed against gamma (?) globulins, are the commonest auto-Ab ever described in man. Some of them are referred to as agglutinating RF, others designated non-agglutinating RF. Not only do these characterize rheumatoid arthritis (RA), but they are also encountered in a variety of disease conditions, as well as a proportion of healthy controls. Although non-specific for RA, the measurement of agglutinating IgM-RF remains the most useful serological test for the diagnosis of this disease. Demonstration of abnormal amount of serum RF by any method for which the result has been positive in less than 5% of normal subjects has indeed become one of the seven revised criteria, listed by the American College of Rheumatology (Arnett, FC, Edworthy, SM, Bloch, DA, McShane, DJ, Fries, JF, Cooper, NS, et al. The American Rheumatism Association 1987 revised criteria for the classification of rheumatoid arthritis. Arthritis Rheum, 1988: 31: 315-24), for the classification of RA. Over the course of years, the relative importance of genetic (Carson, DA, Chen, PP, Kipps, TJ, Radoux, V, Jirik, FR, Goldfien, RD, et al. Idiotypic and genetic studies of human rheumatoid factors. Arthritis Rheum, 1987: 30: 1321-1325) and environmental (Nemazee, DA, Sato, VL. Enhancing antibody, a novel component of the immune response. Proc Natl Acad Sci USA, 1982: 79: 3828-3832) factors in the production of such intriguing auto-Ab has been delineated.     

Multiscale structure of sheet nacre

This work was conducted on Pinctada maxima nacre (mother of pearl) in order to understand its multiscale ordering and the role of the organic matrix in its structure. Intermittent-contact atomic force microscopy with phase detection imaging reveals a nanostructure within the tablet. A continuous organic framework divides each tablet into nanograins. Their shape is supposed to be flat with a mean extension of 45nm. TEM performed in the darkfield mode evidences that at least part of the intracrystalline matrix is crystallized and responds like a 'single crystal'. The tablet is a 'hybrid composite'. The organic matrix is continuous. The mineral phase is thus finely divided still behaving as a single crystal. It is proposed that each tablet results from the coherent aggregation of nanograins keeping strictly the same crystallographic orientation thanks to a hetero-epitaxy mechanism. Finally, high-resolution TEM performed on bridges from one tablet to the next, in the overlying row, did not permit to evidence a mineral lattice but crystallized organic bridges. The same organic bridges were evidenced by SEM in the interlaminar sequence.     

Gastric myeloid metaplasia: a case report and review of the literature

We report a case of gastric myeloid metaplasia in an 89- year-old woman with agnogenic myeloid metaplasia. The lesions were fortuitously discovered on upper endoscopy. The antral mucosa was thickened and polypoid, and on histologic examination contained immature granulocytes, megakaryocytes, and a few erythroblasts without desmoplastic stromal reaction. The granulocytes were positive for CD15, CD68, and myeloperoxidase on immunohistochemistry, and the megakaryocytes showed positive reactivity for factor VIII. Gastric myeloid metaplasia is a very rare event, and to our knowledge only 6 cases have been reported in the literature to date. It usually occurs in patients with advanced myeloproliferative syndrome. Gastric myeloid metaplasia often has a pseudotumoral appearance, leading to digestive symptoms. Histologic diagnosis is straightforward when trilinear hematopoietic elements are identified in gastric biopsies. Immunohistochemistry with anti-factor VIII antibody can be useful to confirm the presence of megakaryocytes.     

Supra-maximal cycling efficiency assessed in humans by using a new protocol

This study proposed a non-invasive method to determine the gross (GE, no baseline correction), net (NE, resting metabolism as the baseline correction) and work (WE, unloaded cycling as the baseline correction) efficiencies during cycling at an intensity higher than the maximal aerobic power (MAP). Twelve male subjects performed two exercises consisting of 4 min at 50% MAP followed either by 8 min at 63% MAP or by 8 sequences of 60 s divided into 10 s at 130% MAP and 50 s at 50% MAP (i.e., 63% MAP on average). Oxygen uptake was continuously measured to calculate GE, NE and WE at 50%, 63% and 130% MAP, and the data presented as the means and standard deviations. The GE values were 18.2%, 19.1%, 22.7%, the NE values were 22.4%, 22.8%, 24.3% and the WE values were 34.2%, 31.4% and 27.2% at 50%, 63% and 130% MAP, respectively. The GE and NE increased (P<0.001) whereas the WE decreased (P<0.001) with each increment in power output. The GE was lower than the NE (P<0.001) at 50% and 63% MAP and than the WE (P<0.001) at all intensities. The NE was lower (P<0.001) than the WE at 50% and 63% MAP. These results showed that (1) efficiency index values obtained during supra-maximal exercise were consistent with previous proposals and (2) the efficiency-power output relationships were not limited to sub-maximal intensity levels but were confirmed at higher power output.     

Dissection of seroreactivity against the tryptophan-rich motif of the feline immunodeficiency virus transmembrane glycoprotein

Immunogenicity of the tryptophan-rich motif (TrpM) in the membrane-proximal ectodomain of the transmembrane (TM) glycoprotein of feline immunodeficiency virus (FIV) was investigated. Peptide 59, a peptide containing the TrpM of the TM of FIV, was covalently coupled to Qbeta phage virus-like particles (Qbeta-59) in the attempt to induce potent anti-TrpM B cell responses in cats. All Qbeta-59 immunized cats, but not cats that received a mixture of uncoupled Qbeta and peptide 59, developed antibodies that reacted with a same epitope in extensive binding and binding competition assays. The epitope recognized was composed of three amino acids, two of which are adjacent. However, Qbeta-59-immune sera failed to recognize whole FIV in all binding and neutralization assays performed. Furthermore, no reactivity against the TrpM was detected by screening sera from FIV-infected cats that had reacted with TM peptides, confirming that this epitope does not seem to be serologically functional in the FIV virion. The data suggest that TrpM may not be a suitable target for antiviral vaccine design.