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Abstract Background Human T-lymphotropic virus type 1 (HTLV-1) proviral load is related to the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and has also been shown to be elevated in the peripheral blood in HTLV-1-infected patients with uveitis or alveolitis. Increased proliferation of HTLV-1-infected cells in, or migration of such cells into, the central nervous system is also seen in HAM/TSP. In the present study, we evaluated the proviral load in a cohort of HTLV-1-infected patients with arthritic conditions. Results HTLV-1 proviral load in the peripheral blood from 12 patients with RA and 6 patients with connective tissue disease was significantly higher than that in matched asymptomatic HTLV-1 carriers, but similar to that in matched HAM/TSP controls. HAM/TSP was seen in one-third of the HTLV-1-infected patients with RA or connective tissue disease, but did not account for the higher proviral load compared to the asymptomatic carrier group. The proviral load was increased in the synovial fluid and tissue from an HTLV-1-infected patient with RA, the values suggesting that the majority of infiltrated cells were HTLV-1-infected. In the peripheral blood from HTLV-1-infected patients with RA or connective tissue disease, HTLV-1 proviral load correlated with the percentages of memory CD4+ T cells and activated T cells, and these percentages were shown to be markedly higher in the synovial fluid than in the peripheral blood in an HTLV-1-infected patient with RA. Conclusions These biological findings are consistent with a role of the retrovirus in the development of arthritis in HTLV-1-infected patients. A high level of HTLV-1-infected lymphocytes in the peripheral blood and their accumulation in situ might play a central role in the pathogenesis of HTLV-1-associated inflammatory disorders. Alternatively, the autoimmune arthritis, its etiological factors or treatments might secondarily enhance HTLV-1 proviral load.

Consumption coagulopathy and hemorrhagic syndrome exacerbated by blood anticoagulability remain the most important causes of lethality associated with Bothrops snake envenomation. Bothrops venom also engages platelet aggregation on the injured endothelium via von Willebrand factor (vWF) interactions. Besides platelet aggregation, some Bothrops venom toxins may induce qualitative thrombopathy, which has been in part related to the inhibition of vWF activation. We tested whether B. lanceolatus venom impaired vWF to collagen(s) binding (vWF:CB) activity. Experiments were performed with B. lanceolatus crude venom, in the presence or absence of Bothrofav, a monospecific B. lanceolatus antivenom. Venom of B. lanceolatus fully inhibited vWF to collagen type I and III binding, suggesting venom interactions with the vWF A3 domain. In contrast, B. lanceolatus venom increased vWF to collagen type VI binding, suggesting the enhancement of vWF binding to collagen at the vWF A1 domain. Hence, B. lanceolatus venom exhibited contrasting in vitro effects in terms of the adhesive properties of vWF to collagen. On the other hand, the antivenom Bothrofav reversed the inhibitory effects of B. lanceolatus venom on vWF collagen binding activity. In light of the respective distribution of collagen type III and collagen type VI in perivascular connective tissue and the sub-endothelium, a putative association between an increase in vWF:CB activity for collagen type VI and the onset of thrombotic events in human B. lanceolatus envenomation might be considered.

Introduction: Envenomations by Bothrops snakebites can induce overwhelming systemic inflammation ultimately leading to multiple organ system failure and death. Release of damage-associated molecular pattern molecules (DAMPs), in particular of mitochondrial origin, has been implicated in the pathophysiology of the deregulated innate immune response., Objective: To test whether whole Bothrops lanceolatus venom would induce mitochondrial dysfunction and DAMPs release in human heart preparations., Methods: Human atrial trabeculae were obtained during cannulation for cardiopulmonary bypass from patients who were undergoing routine coronary artery bypass surgery. Cardiac fibers were incubated with vehicle and whole Bothrops lanceolatus venom for 24hr before high-resolution respirometry, mitochondrial membrane permeability evaluation and quantification of mitochondrial DNA., Results: Compared with vehicle, incubation of human cardiac muscle with whole Bothrops lanceolatus venom for 24hr impaired respiratory control ratio and mitochondrial membrane permeability. Levels of mitochondrial DNA increased in the medium of cardiac cell preparation incubated with venom of Bothrops lanceolatus., Conclusion: Our study suggests that whole venom of Bothrops lanceolatus impairs mitochondrial oxidative phosphorylation capacity and increases mitochondrial membrane permeability. Cardiac mitochondrial dysfunction associated with mitochondrial DAMPs release may alter myocardium function and engage the innate immune response, which may both participate to the cardiotoxicity occurring in patients with severe envenomation., Competing Interests: The authors have declared that no competing interests exist.

Background: Human T-lymphotropic virus type 1 (HTLV-1) proviral load is related to the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and has also been shown to be elevated in the peripheral blood in HTLV-1-infected patients with uveitis or alveolitis. Increased proliferation of HTLV-1-infected cells in, or migration of such cells into, the central nervous system is also seen in HAM/TSP. In the present study, we evaluated the proviral load in a cohort of HTLV-1-infected patients with arthritic conditions., Results: HTLV-1 proviral load in the peripheral blood from 12 patients with RA and 6 patients with connective tissue disease was significantly higher than that in matched asymptomatic HTLV-1 carriers, but similar to that in matched HAM/TSP controls. HAM/TSP was seen in one-third of the HTLV-1-infected patients with RA or connective tissue disease, but did not account for the higher proviral load compared to the asymptomatic carrier group. The proviral load was increased in the synovial fluid and tissue from an HTLV-1-infected patient with RA, the values suggesting that the majority of infiltrated cells were HTLV-1-infected. In the peripheral blood from HTLV-1-infected patients with RA or connective tissue disease, HTLV-1 proviral load correlated with the percentages of memory CD4+ T cells and activated T cells, and these percentages were shown to be markedly higher in the synovial fluid than in the peripheral blood in an HTLV-1-infected patient with RA., Conclusions: These biological findings are consistent with a role of the retrovirus in the development of arthritis in HTLV-1-infected patients. A high level of HTLV-1-infected lymphocytes in the peripheral blood and their accumulation in situ might play a central role in the pathogenesis of HTLV-1-associated inflammatory disorders. Alternatively, the autoimmune arthritis, its etiological factors or treatments might secondarily enhance HTLV-1 proviral load.

The transcription factors STAT5A and STAT5B (STAT: signal transducer and activator of transcription) play a major role in the signaling events elicited by a number of growth factor and cytokine receptors. In this work, we aimed to investigate the role of STAT5 in human precursor B cell survival by introducing dominant-negative (DN) forms of STAT5A or STAT5B in the 697 pre-B cell line. All clones expressing DN forms of either transcription factor exhibited a higher spontaneous apoptotic rate that was massively enhanced upon interleukin-7 (IL-7) stimulation. This was associated with caspase 8 cleavage, mitochondrial transmembrane potential disruption and caspase 3 activation. However, the DN forms of STAT5 did not alter the expression of Bcl-2, Bax, Bcl-x, Bim, A1 and Mcl1 proteins in IL-7-stimulated cells. The pancaspase inhibitor Z-Val-Ala-Asp-fluoromylmethyl ketone partially suppressed IL-7-mediated mitochondrial transmembrane potential disruption and cell death, suggesting that IL-7 induced the death of DN STAT5 expressing 697 cells through caspase-dependent and -independent mechanisms that both require mitochondrial activation.

Background: WBC depletion by filtration may prevent the transmission of HTLV-I, which requires cell-to-cell contact. The removal of HTLV-I-infected cells in routinely filtered blood cell components was measured., Study Design and Methods: The study was conducted in Martinique where systematic screening for HTLV-I and -II and universal leukoreduction are mandatory. HTLV-I was quantified by use of real-time PCR in 8 RBC units and 4 PLT concentrates before and after filtration. HTLV-I proviral load in PBMNCs was determined in five of the eight HTLV-I-infected blood donors., Results: The amount of MNC-associated HTLV-I DNA in RBC units before filtration was 21 x 10(6)+/- 29 x 10(6) copies (mean +/- SD). HTLV-I was detected in 4 of 8 RBC units after filtration, with a number of copies in the MNC fraction ranging from 20 to 140, following a 4.9 to 5.8 log reduction. Flow cytometry analysis performed in 2 of the filtered RBC units containing detectable HTLV-I showed suboptimal and out-of-range leukoreduction (0.56 x 10(6) and 1.22 x 10(6) residual WBCs). HTLV was not detected in filtered RBCs from the blood donor with the highest percentage of HTLV-I-infected PBMCs (9%)., Conclusion: This study confirms that HTLV-I-infected cells can be detected in filtered blood cell components and shows that optimal leukoreduction is critical for HTLV-I removal.

Several reports suggest that HTLV-I/HIV coinfection may be associated with an increased risk of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). In HTLV-I-monoinfected patients, the occurrence of HAM/TSP is associated with high peripheral blood HTLV-I proviral load. Using a real-time quantitative PCR assay, we assessed the proviral DNA load in peripheral blood mononuclear cells (PBMCs) from 15 asymptomatic HTLV-I-monoinfected patients, 15 HTLV-I-monoinfected patients with HAM/TSP, and 25 HTLV-I/HIV-1 coinfected patients, including 4 with HAM/TSP. We also measured HIV-1 proviral DNA load in PBMCs from the coinfected patients. The median HTLV-I proviral loads were 6,800 and 4,100 copies per 10(6) PBMCs in the asymptomatic monoinfected and coinfected groups, and 58,800 and 43,300 copies per 10(6) PBMCs in the monoinfected and coinfected patients with HAM/TSP, respectively. The difference between HTLV-I proviral loads in HAM/TSP and asymptomatic monoinfected patients was statistically significant (p < 0.0001), but there was no difference between the HTLV-I-monoinfected and HTLV-I/HIV-1-coinfected groups. There was no correlation between HTLV-I and HIV-1 proviral load. HTLV-I proviral load did not correlate with the CD4+ T lymphocyte count. Among patients with no HTLV-I disease, the median copy number of HTLV-I per 10(6) circulating CD4+ T cells was 114,000 in the coinfected group and 16,700 in the monoinfected group, but the difference was not significant (p = 0.089). These data do not confirm the hypothesis in which HIV-1 coinfection would increase HTLV-I proviral burden in the PBMCs. However, depletion of the CD4+ T cell subset, the main target of HTLV-I, could be counterbalanced by an up-regulation of HTLV-I replication or by greater resistance of HTLV-I-infected cells to HIV-1-induced destruction.

It is now well established that oxidized LDL (OxLDL) is involved in the progression of the atheromatous plaque via several mechanisms, including its cytotoxicity toward the arterial wall. Our study demonstrates that a 4-h incubation of cultured human fibroblasts with 25-75 microg/ml OxLDL induced a dose-dependent increase in the intracellular levels of reactive oxygen species (ROS) and lipid peroxidation end products (TBARS). This effect was markedly prevented by the antioxidant vitamin E. The lipid extract of OxLDL partially reproduced the action of the LDL particle itself. Concomitantly, OxLDL enhanced the DNA binding activity of p53 measured by electrophoretic mobility shift assay, and the intracellular protein level of p53 determined by immunoblot analysis. Cycloheximide prevented the OxLDL-induced augmentation in both p53 binding activity and intracellular level. Again, the lipid extract of OxLDL reproduced the effect of OxLDL on p53 binding activity, whereas vitamin E prevented it. These results indicate that OxLDL initiates an intracellular oxidative stress by means of its lipid peroxidation products, leading to the activation of the tumour suppressor p53 by enhancement of p53 protein synthesis. This effect might be related to the cytotoxic effect of OxLDL since the activation of p53 is known to lead to cell cycle arrest, necrosis or apoptosis., (Copyright 2000 Academic Press.)

Oxidative modification of low-density lipoprotein (LDL) is an important feature in the initiation and progression of atherosclerosis. LDL modification by endothelial cells was studied after supplementation of the cells with oleic acid and polyunsaturated fatty acids (PUFA) of the n-6 and n-3 series. In terms of the lipid peroxidation product [thiobarbituric acid reactive substances (TBARS)] content and diene level of the LDL particle, oleic acid had no significant effect, and linoleic acid was poorly effective. Gamma linolenic acid (C18:3,n-6) and arachidonic acid (C20:4,n-6) increased by about 1.6-1.9-fold the cell-mediated LDL modification. PUFA from the n-3 series, alpha linolenic acid (C18:3,n-3), eicosapentaenoic acid (C20:5,n-3) and docosahexaenoic acid (C22:6,n-3), induced a less marked effect (1. 3-1.6-fold increase). The relative electrophoretic mobility of the LDL particle and its degradation by macrophages were enhanced in parallel. Concomitantly, PUFA stimulated superoxide anion secretion by endothelial cells. The intracellular TBARS content was also increased by PUFA. Comparison of PUFA from the two series indicates a good correlation between LDL oxidative modification, superoxide anion secretion and intracellular lipid peroxidation. The lipophilic antioxidant vitamin E decreased the basal as well as the PUFA-stimulated LDL peroxidation. These results indicate that PUFAs with a high degree of unsaturation of the n-6 and n-3 series could accelerate cell-mediated LDL peroxidation and thus aggravate the atherosclerotic process.

Analytical ion microscopy, a method proposed and developed in 1960 by Casting and Slodzian at the Orsay University (France), makes it possible to obtain easily and rapidly analytical images representing the distribution in a tissue section of elements or isotopes (beginning from the three isotopes of hydrogen until to transuranic elements), even when these elements or isotopes are at a trace concentration of 1 ppm or less. This method has been applied to study the subcellular distribution of different varieties of biomolecules. The subcellular location of these molecules can be easily determined when the molecules contain in their structures a specific atom such as fluorine, iodine, bromine or platinum, what is the case of many pharmaceutical drugs. In this situation, the distribution of these specific atoms can be considered as representative of the distribution of the corresponding molecule. In other cases, the molecules must be labelled with an isotope which may be either radioactive or stable. Recent developments in ion microscopy allow the obtention of their chemical images at ultra structural level. In this paper we present the results obtained with the prototype of a new Scanning Ion Microscope used for the study of the intracellular distribution of different varieties of molecules: glucocorticoids, estrogens, pharmaceutical drugs and pyrimidine analogues.

The effects of selenium and silver salts was studied by scanning ionic microscopy during experimental argyria mapping of the different basement membrane elements. The ionic microscope (IMS 4F) was equipped with a high resolution spectrometer giving high spatial resolution on the image obtained. After long-term treatment with silver salt alone, silver and sulphur deposits were observed in the membranes. After administration of selenium and silver salt, it was possible to map nitrogen, sulphur, selenium and silver to the glomerular basement membrane as well as to the wall of the kidney arterioles. In the latter, sulphur, selenium and silver were localized only in the elastic laminae of the walls. This process of precipitation of silver deposits in the membrane can be interpreted as process of selenium "detoxification" of the organism.