49 research outputs found
Effect of various glycosidase treatments on the resistance of the HIV-1 envelope to degradation
AbstractUsing a CD4-binding assay to assess the conformation of the human immunodeficiency virus envelope glycoprotein (CHO+Env), we studied the effect of treatment with various glycosidases on the stability of Env in denaturing environments and in biological media: cleavage from Env of either high-mannose-type glycans (HMTâEnv) by endoglycosidaseH or sialic acid residues (SialâEnv) by sialidase did not alter Env stability whereas its complete deglycosylation (CHOâEnv) by N-glycanase had a large effect. The influence of glycan removal on Env sensitivity to proteases was also studied. Thrombin cleavage within V3 was affected by N-glycanase treatment; both HMTâEnv and CHOâEnv displayed an increased sensitivity to other endoproteases. Thus, partial deglycosylation increases Env sensitivity to proteases but only its total deglycosylation alters its stability
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OX133, a monoclonal antibody recognizing protein-bound N-ethylmaleimide for the identification of reduced disulfide bonds in proteins
In vivo, enzymatic reduction of some protein disulfide bonds, allosteric disulfide bonds, provides an important level of structural and functional regulation. The free cysteine residues generated can be labeled by maleimide reagents, including biotin derivatives, allowing the reduced protein to be detected or purified. During the screening of monoclonal antibodies for those specific for the reduced forms of proteins, we isolated OX133, a unique antibody that recognizes polypeptide resident, N-ethylmaleimide (NEM)-modified cysteine residues in a sequence-independent manner. OX133 offers an alternative to biotin-maleimide reagents for labeling reduced/alkylated antigens and capturing reduced/alkylated proteins with the advantage that NEM-modified proteins are more easily detected in mass spectrometry, and may be more easily recovered than is the case following capture with biotin based reagents
Effectiveness of pure argon for renal transplant preservation in a preclinical pig model of heterotopic autotransplantation
International audienceBackground: In kidney transplantation, the conditions of organ preservation following removal influence function recovery. Current static preservation procedures are generally based on immersion in a coldâstorage solution used under atmospheric air (approximately 78 kPa N2, 21 kPa O2, 1 kPa Ar). Research on static coldâpreservation solutions has stalled, and modifying the gas composition of the storage medium for improving preservation was considered. Organoprotective strategies successfully used noble gases and we addressed here the effects of argon and xenon on graft preservation in an established preclinical pig model of autotransplantation. Methods: The preservation solution Celsior saturated with pure argon (ArgonâCelsior) or xenon (XenonâCelsior) at atmospheric pressure was tested versus Celsior saturated with atmospheric air (AirâCelsior). The left kidney was removed, and AirâCelsior (n = 8 pigs), ArgonâCelsior (n = 8) or XenonâCelsior (n = 6) was used at 4 °C to flush and store the transplant for 30 h, a duration that induced ischemic injury in our model when AirâCelsior was used. Heteroâ topic autotransplantation and contralateral nephrectomy were performed. Animals were followed for 21 days. Results: The use of ArgonâCelsior vs. AirâCelsior: (1) improved function recovery as monitored via creatinine clearâ ance, the fraction of excreted sodium and tubulopathy duration; (2) enabled diuresis recovery 2â3 days earlier; (3) improved survival (7/8 vs. 3/8 pigs survived at postoperative dayâ21); (4) decreased tubular necrosis, interstitial fibrosis, apoptosis and inflammation, and preserved tissue structures as observed after the natural death/euthanasia; (5) stimulated plasma antioxidant defences during the days following transplantation as shown by monitoring the " reduced ascorbic acid/thiobarbituric acid reactive substances " ratio and Hsp27 expression; (6) limited the inflammaâ tory response as shown by expression of TNFâalpha, IL1âbeta and IL6 as observed after the natural death/euthanasia. Conversely, XenonâCelsior was detrimental, no animal surviving by dayâ8 in a context where functional recovery, renal tissue properties and the antioxidant and inflammation responses were significantly altered. Thus, the positive effects of argon were not attributable to the noble gases as a group. Conclusions: The saturation of Celsior with argon improved early functional recovery, graft quality and survival. Manipulating the gas composition of a preservation medium constitutes therefore a promising approach to improve preservation
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Pathophysiological and diagnostic implications of cardiac biomarkers and antidiuretic hormone release in distinguishing immersion pulmonary edema from decompression sickness
Immersion pulmonary edema (IPE) is a misdiagnosed environmental illness caused by water immersion, cold, and exertion. IPE occurs typically during SCUBA diving, snorkeling, and swimming. IPE is sometimes associated with myocardial injury and/or loss of consciousness in water, which may be fatal. IPE is thought to involve hemodynamic and cardiovascular disturbances, but its pathophysiology remains largely unclear, which makes IPE prevention difficult. This observational study aimed to document IPE pathogenesis and improve diagnostic reliability, including distinguishing in some conditions IPE from decompression sickness (DCS), another diving-related disorder.
Thirty-one patients (19 IPE, 12 DCS) treated at the Hyperbaric Medicine Department (Ste-Anne hospital, Toulon, France; July 2013âJune 2014) were recruited into the study. Ten healthy divers were recruited as controls. We tested: (i) copeptin, a surrogate marker for antidiuretic hormone and a stress marker; (ii) ischemia-modified albumin, an ischemia/hypoxia marker; (iii) brain-natriuretic peptide (BNP), a marker of heart failure, and (iv) ultrasensitive-cardiac troponin-I (cTnI), a marker of myocardial ischemia.
We found that copeptin and cardiac biomarkers were higher in IPE versus DCS and controls: (i) copeptin: 68% of IPE patients had a high level versus 25% of DCS patients (Pâ<â0.05) (meanâ±âstandard-deviation: IPE: 53â±â61âpmol/L; DCS: 15â±â17; controls: 6â±â3; IPE versus DCS or controls: Pâ<â0.05); (ii) ischemia-modified albumin: 68% of IPE patients had a high level versus 16% of DCS patients (Pâ<â0.05) (IPE: 123â±â25 arbitrary-units; DCS: 84â±â25; controls: 94â±â7; IPE versus DCS or controls: Pâ<â0.05); (iii) BNP: 53% of IPE patients had a high level, DCS patients having normal values (Pâ<â0.05) (IPE: 383â±â394âng/L; DCS: 37â±â28; controls: 19â±â15; IPE versus DCS or controls: Pâ<â0.01); (iv) cTnI: 63% of IPE patients had a high level, DCS patients having normal values (Pâ<â0.05) (IPE: 0.66â±â1.50âÎŒg/L; DCS: 0.0061â±â0.0040; controls: 0.0090â±â0.01; IPE versus DCS or controls: Pâ<â0.01). The combined âBNP-cTnIâ levels provided most discrimination: all IPE patients, but none of the DCS patients, had elevated levels of either/both of these markers.
We propose that antidiuretic hormone acts together with a myocardial ischemic process to promote IPE. Thus, monitoring of antidiuretic hormone and cardiac biomarkers can help to make a quick and reliable diagnosis of IPE
Modulation de la biosynthese des motifs glucidiques de la thyroglobuline : leurs roles sur son organisation spatiale
SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
Adenosine Receptor Profiling Reveals an Association between the Presence of Spare Receptors and Cardiovascular Disorders
Adenosine and its receptors exert a potent control on the cardiovascular system. This review aims to present emerging experimental evidence supporting the existence and implication in cardiovascular disorders of specific adenosinergic pharmacological profiles, conforming to the concept of “receptor reserve”, also known as “spare receptors”. This kind of receptors allow agonists to achieve their maximal effect without occupying all of the relevant cell receptors. In the cardiovascular system, spare adenosine receptors appear to compensate for a low extracellular adenosine level and/or a low adenosine receptor number, such as in coronary artery disease or some kinds of neurocardiogenic syncopes. In both cases, the presence of spare receptors appears to be an attempt to overcome a weak interaction between adenosine and its receptors. The identification of adenosine spare receptors in cardiovascular disorders may be helpful for diagnostic purposes
Relationships between the anti-HIV V 3 -derived peptide SPC 3 and lymphocyte membrane properties involved in virus entry: SPC 3 interferes with CXCR 4
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An Anti-HIV Peptide Construct Derived from the Cleavage Region of the Env Precursor Acts on Env Fusogenicity through the Presence of a Functional Cleavage Sequence
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