Insufficient vaccine coverage and vaccine hesitancy in people living with HIV: A prospective study in outpatient clinics in the Paris region.

Vaccine prevention strategies play a crucial role in the management of people living with HIV (PLWH). The aim of this study was to assess vaccination coverage and identify barriers to vaccine uptake in PLWH in the Paris region. A cross-sectional survey was conducted in PLWH in 16 hospitals in the Paris region. The vaccination status, characteristics, opinions, and behaviors of participants were collected using a face-to-face questionnaire and from medical records. A total of 338 PLWH were included (response rate 99.7 %). The median age of participants was 51 years (IQR: 41-58). Vaccination coverage was 77.3 % for hepatitis B (95 % CI: 72.3-81.8 %), 62.7 % for hepatitis A (57.3-67.9 %), 61.2 % for pneumococcal vaccines (55.8-66.5 %), 56.5 % for diphtheria/tetanus/poliomyelitis (DTP) (51.0-61.9 %), 44.7 % for seasonal influenza (39.3-50.1 %), 31.4 % for measles/mumps/rubella (26.4-36.6 %) and 38.5 % for meningococcal vaccine (13.9-68.4 %). The main reason for vaccine reluctance was related to the lack of vaccination proposals/reminders. The overall willingness to get vaccinated was 71.0 % (65.9-75.8 %). In the multivariable analysis, several factors were associated with a higher vaccine uptake; for DTP vaccine: higher education level, having vaccination records, being registered with a general practitioner; for seasonal influenza vaccine: age > 60 years, higher education level, being employed. The overall vaccination coverage was suboptimal. Development of strategies reducing missed opportunity to offer vaccines is needed.

An Arabidopsis Rab18 GTPase promotes autophagy by tethering ATG18a to the ER in response to nutrient starvation.

The expansion of autophagosomes requires a controlled association with the endoplasmic reticulum (ER). However, the mechanisms governing this process are not well defined. In plants, ATG18a plays a key role in autophagosome formation in response to stress, yet the factors regulating the process are unknown. This study finds that ATG18a acts as a downstream effector of RABC1, a member of the poorly characterized Rab18/RabC GTPase subclass in plants. Active RABC1 interacts with ATG18a on the ER, particularly under nutrient starvation. In rabc1 mutants, autophagy is compromised, especially under nutrient deprivation, affecting the ER association and expansion of ATG18a-positive autophagosomes. Furthermore, both dominant-negative and constitutively active RABC1 forms inhibit autophagy. The dominant inactive RABC1 impedes the ER association of ATG18a, whereas the constitutively active RABC1 delays ATG18a detachment from the ER. Collectively, RABC1 regulates the ER association and the subsequent detachment of ATG18a-positive autophagosomes during nutrient starvation.

Knowledge of recommended antibiotic treatments for community-acquired infections in general medical practice: a cross-sectional study in Occitanie region, France.

To assess and analyse the knowledge of recommended antibiotic treatments, focusing on the appropriate drugs and treatment durations for the most common community-acquired infections in general medical practice in Occitanie region, France. A web-based survey was conducted over a 3-month period, from October, 2018 to January, 2019. All participants answered directly through the online platform. For the analysis of overtreatment risk, a score based system was adopted and two scores were produced: the duration score and the treatment score. 413 general practitioners completed the survey. The overall rate of concordance with guidelines in terms of both drug choice and treatment length was 2974/4956 (60%) answers. Diseases with at least 70% good answers included cystitis, group A streptococcal pharyngitis, and bacterial superficial skin infections. Diseases with fewer than 50% good answers included pyelonephritis, dog bite wounds, and community-acquired pneumonia in patients aged ≥ 65 years. Factors associated with the risk of overtreatment were age > 40 years, country setting and hospital employment. Knowledge of treatment durations is satisfactory with 60% of recommendations being met. However, varying levels were observed according to different diseases. This study highlighted a very high rate of adherence when recommendations were clear. In contrast, low levels of adherence were observed when recommendations were ambiguous or when conflicting guidelines existed.

Updated mortality and causes of death in 2020-2021 in people with HIV: a multicenter study in France.

OBJECTIVE: The aim of this study was to assess updated mortality and causes of death in people with HIV (PWH) in France. DESIGN AND METHODS: We analyzed all deaths in PWH followed up between January 1, 2020, and December 31, 2021, in 11 hospitals in the Paris region. We described the characteristics and causes of death among deceased PWH, and evaluated the incidence of mortality and associated risk factors using a multivariate logistic regression. RESULTS: Of the 12 942 patients followed in 2020--2021, 202 deaths occurred. Mean annual incidence of death [95% confidence interval (95% CI)] was 7.8 per 1000 PWH (6.3-9.5). Forty-seven patients (23%) died from non-AIDS nonviral hepatitis (NANH)-related malignancies, 38 (19%) from non-AIDS infections (including 21 cases of COVID-19), 20 (10%) from AIDS, 19 (9%) from cardiovascular diseases (CVD), 17 (8.4%) from other causes, six (3%) from liver diseases, and five (2.5%) from suicides/violent deaths. The cause of death was unknown in 50 (24.7%) patients. Risks factors for death were age [adjusted odds ratio (aOR) 1.93; 1.66-2.25 by additional decade), AIDS history (2.23; 1.61-3.09), low CD4 + cell count (1.95; 1.36-2.78 for 200-500 cells/µl and 5.76; 3.65-9.08 for ≤200 versus > 500 cells/µl), and viral load more than 50 copies/ml (2.03; 1.33-3.08), both at last visit. CONCLUSION: NANH malignancies remained in 2020-2021 the first cause of death. COVID-19 accounted for more than half of the mortality related to non-AIDS infections over the period. Aging, AIDS history, and a poorer viro-immunological control were associated with death.

Prescription of antibiotics by general practitioners for patients with a diagnosis of SARS- CoV-2 infection: Analysis of an electronic French health record.

OBJECTIVE: To define the factors associated with overprescription of antibiotics by general practitioners (GPs) for patients diagnosed with COVID-19 during the first wave of the pandemic. METHODS: Anonymised electronic prescribing records of 1370 GPs were analysed. Diagnosis and prescriptions were retrieved. The initiation rate by GP for 2020 was compared with 2017-2019. Prescribing habits of GPs who initiated antibiotics for > 10% of COVID-19 patients were compared with those who did not. Regional differences in prescribing habits of GPs who had consulted at least one COVID-19 patient were also analysed. RESULTS: For the March-April 2020 period, GPs who initiated antibiotics for > 10% of COVID-19 patients had more consultations than those who did not. They also more frequently prescribed antibiotics for non-COVID-19 patients consulting with rhinitis and broad-spectrum antibiotics for treating cystitis. Finally, GPs in the Île-de-France region saw more COVID-19 patients and more frequently initiated antibiotics. General practitioners in southern France had a higher but non-significant ratio of azithromycin initiation rate over total antibiotic initiation rate. CONCLUSION: This study identified a subset of GPs with overprescribing profiles for COVID-19 and other viral infections; they also tended to prescribe broad-spectrum antibiotics for a long duration. There were also regional differences concerning antibiotic initiation rates and the ratio of azithromycin prescribed. It will be necessary to evaluate the evolution of prescribing practices during subsequent waves.

Structural insights into the interactions of glutathione transferases with a nitric oxide carrier and sodium nitroprusside.

Glutathione transferases are detoxification enzymes with multifaceted roles, including a role in the metabolism and scavenging of nitric oxide (NO) compounds in cells. Here, we explored the ability of Trametes versicolor glutathione transferases (GSTs) from the Omega class (TvGSTOs) to bind metal-nitrosyl compounds. TvGSTOs have been studied previously for their ligandin role and are interesting models to study protein‒ligand interactions. First, we determined the X-ray structure of the TvGSTO3S isoform bound to the dinitrosyl glutathionyl iron complex (DNGIC), a physiological compound involved in the storage of nitric oxide. Our results suggested a different binding mode compared to the one previously described in human GST Pi 1 (GSTP1). Then, we investigated the manner in which TvGSTO3S binds three nonphysiological metal-nitrosyl compounds with different metal cores (iron, ruthenium and osmium). We assayed sodium nitroprusside, a well-studied vasodilator used in cases of hypertensive crises or heart failure. Our results showed that the tested GST can bind metal-nitrosyls at two distinct binding sites. Thermal shift analysis with six isoforms of TvGSTOs identified TvGSTO6S as the best interactant. Using the Griess method, TvGSTO6S was found to improve the release of nitric oxide from sodium nitroprusside in vitro, whereas the effects of human GST alpha 1 (GSTA1) and GSTP1 were moderate. Our results open new structural perspectives for understanding the interactions of glutathione transferases with metal-nitrosyl compounds associated with the biochemical mechanisms of NO uptake/release in biological systems.

Factors associated with delay in seeking healthcare for imported malaria: a retrospective study in a French hospital.

BACKGROUND: Delayed treatment is associated with a higher risk of severe malaria. In malaria-endemic areas, the main factors associated with delay in seeking healthcare are low educational level and traditional beliefs. In imported malaria, determinants of delay in seeking healthcare are currently unknown. METHODS: We studied all patients presenting with malaria, from 1 January 2017 to 14 February 2022, in the hospital of Melun, France. Demographic and medical data were recorded for all patients, and socio-professional data were recorded for a subgroup of hospitalized adults. Relative-risks and 95% confidence intervals were determined using univariate analysis by cross-tabulation. RESULTS: There were 234 patients included, all travelling from Africa. Among them, 218 (93%) were infected with P. falciparum, 77 (33%) had severe malaria, 26 (11%) were <18 years old and 81 were included during the SARS-CoV-2 pandemic. There were 135 hospitalized adults (58% of all patients). The median time to hospital admission (THA) , defined by the period from onset of symptoms to arrival at hospital, was 3 days (IQR = 2-5). A THA ≥3 days tended to be more frequent in travellers visiting friends and relatives (VFR; RR = 1.44, 95% CI = [1.0-2.05], P = 0.06), while it was less frequent in children and teenagers (RR = 0.58, 95% CI = [0.39-0.84], P = 0.01). Gender, African background, unemployment, living alone and absence of referring physician were not associated with delay in seeking healthcare. Consulting during the SARS-CoV-2 pandemic was neither associated with a longer THA nor with a higher rate of severe malaria. CONCLUSION: In contrast to an endemic area, socio-economic factors did not impact on delay in seeking healthcare in imported malaria. Prevention should focus on VFR subjects, who tend to consult later than other travellers.

Same-day discharge to home is feasible and safe in up to 75% of unselected total hip and knee arthroplasty.

PURPOSE: Though numerous studies highlighted benefits of ambulatory total joint arthroplasty (TJA), most had selected patients with age and comorbidities thresholds. We aimed to report proportions of unselected TJAs that could be scheduled for and operated in ambulatory settings, and to determine factors that hinder same-day discharge (SDD). METHODS: We studied 1100 consecutive primary TJAs (644 THAs and 456 TKAs) that were prepared following a multidisciplinary protocol for patient education and logistical preparation. Data were stratified for THA vs TKA and for success vs failure of SDD to home and multivariable analysis was performed to determine factors associated with failure of scheduled SDD to home. RESULTS: In total, 860 (78.2%) were scheduled for ambulatory surgery, but only 819 (74.5%) achieved SDD to home; 240 (21.8%) were scheduled for non-ambulatory surgery, but 103 (9.3%) achieved SDD to rehabilitation centre. Re-operations were required in 9 (1.0%) ambulatory TJAs vs 2 (0.8%) non-ambulatory TJAs (p = 0.769), while revisions were required in 13 (1.5%) ambulatory TJAs vs 1 (0.4%) non-ambulatory TJAs (p = 0.181). Multivariable analysis confirmed that failure of SDD to home was greater for women (OR 2.59; p = 0.011) and THA (vs TKA, OR 2.41; p = 0.023). CONCLUSION: With appropriate education and preparation, 75% of unselected primary hip and knee arthroplasties achieved SDD to home without compromising risks of complications, re-operations, or revisions. A further 9% achieved SDD to rehabilitation centre, implying that 84% of patients did not require overnight stay. These findings suggest that ambulatory surgery is feasible and safe to implement in most unselected lower limb arthroplasties.

Risk of Multidrug Resistant Bacteria Acquisition in Patients with Declared ß-Lactam Allergy during Hospitalization in Intensive Care Unit: A Retrospective Cohort Study (2007-2018).

INTRODUCTION: The risk of extended spectrum ß-lactamase (ESBL) bacterial acquisition in patients with ß-lactam allergy has been poorly investigated. In a previous study conducted over a 6-year long period (2007-2012), we found that patients with declared ß-lactam allergy had a higher risk of ESBL bacterial carriage at admission in intensive care unit (ICU), but they had not a higher risk of ESBL bacterial acquisition. We present the final results of the study which was eventually conducted over a 12-year long period (2007-2018). MATERIALS AND METHODS: The study included all patients admitted in ICU and receiving antibiotic treatment from January 2007 to December 2018. ESBL bacterial acquisition was the main clinical outcome. Mortality in ICU, multidrug resistant bacterial carriage at admission and discharge were the secondary outcomes. RESULTS: Overall, 3332 patients were included, 132/3332 (3.9%) were labelled ß-lactam allergic, while 3200/3332 (96.1%) did not presented ß-lactam allergy. No significant difference in rates of ESBL acquisition was detected (4/132, 3% vs. 78/3200, 2.4%; p = 0.17). Patients with ß-lactam allergy had higher rates of ESBL bacterial carriage at admission (19/132, 14.4% vs. 248/3200, 7.8%, p = 0.01) and at discharge (22/132, 16.7% vs. 351/3200, 11%, p = 0.04) than nonallergic patients. No differences in mortality, duration of hospitalization, and carriage of methicillin resistant Staphylococcus aureus were reported. Female gender was the only factor associated with ß-lactam allergy at the multivariate analysis. CONCLUSIONS: This study confirms that patients with declared ß-lactam allergy had not a higher risk of ESBL bacterial acquisition during hospitalization in ICU. However, they had a higher ESBL bacterial carriage at admission.

Selenium Donors at the Junction of Inflammatory Diseases.

Selenium is an essential non-metal trace element, and the imbalance in the bioavailability of selenium is associated with many diseases ranking from acute respiratory distress syndrome, myocardial infarction and renal failure (Se overloading) to diseases associated with chronic inflammation like inflammatory bowel diseases, rheumatoid arthritis, and atherosclerosis (Se unload). The only source of selenium is the diet (animal and cereal sources) and its intestinal absorption is limiting for selenocysteine and selenomethionine synthesis and incorporation in selenoproteins. In this review, after establishing the link between selenium and inflammatory diseases, we envisaged the potential of selenium nanoparticles and organic selenocompounds to compensate the deficit of selenium intake from the diet. With high selenium loading, nanoparticles offer a low dosage to restore selenium bioavailability whereas organic selenocompounds can play a role in the modulation of their antioxidant or antiinflammatory activities.

Labeling nitrogen species with the stable isotope 15N for their measurement by separative methods coupled with mass spectrometry: A review.

Nitrogen and its numerous hydrogenated and oxygenated derivatives are of main importance in our environment and in living cells as well in both qualitative and quantitative aspects. Their monitoring is needed to evaluate all disturbances occurring in the nitrogen cycle and in pathophysiological events related to variations of nitric oxide (NO) bioavailability. Many analytical methods are devoted to the measurement of nitrogen species, especially those related to NO, in the environmental, biological and pharmacological fields, and they have already been compiled and discussed in numerous reviews. Nitrogen isotope (15N) is stable and has a low level of natural abundance. Labeling nitrogen species with 15N associated with mass spectrometry (MS) gives rise to more mechanistic information and improved analytical performances compared to conventional methods. The present review is dedicated to the 15N labeling of related nitrogen species to monitor their interconversion and metabolism, the different chemical probes used for their derivatization and the corresponding separative methods coupled with MS for analyzing resulting adducts. The fragmentation mode of the different adducts and the resulting selectivity and sensitivity are discussed.

Higher-energy collision-induced dissociation for the quantification by liquid chromatography/tandem ion trap mass spectrometry of nitric oxide metabolites coming from S-nitroso-glutathione in an in vitro model of the intestinal barrier.

RATIONALE: The potency of S-nitrosoglutathione (GSNO) as a nitric oxide (NO) donor to treat cardiovascular diseases (CVDs) has been highlighted in numerous studies. In order to study its bioavailability after oral administration, which represents the most convenient route for the chronic treatment of CVDs, it is essential to develop an analytical method permitting (i) the simultaneous measurement of GSNO metabolites, i.e. nitrite, S-nitrosothiols (RSNOs) and nitrate and (ii) to distinguish them from other sources (endogenous synthesis and diet). METHODS: Exogenous GSNO was labeled with 15 N, and the GS15 NO metabolites after conversion into the nitrite ion were derivatized with 2,3-diaminonaphthalene. The resulting 2,3-naphthotriazole was quantified by liquid chromatography/tandem ion trap mass spectrometry (LC/ITMS/MS) in multiple reaction monitoring mode after Higher-energy Collision-induced Dissociation (HCD). Finally, the validated method was applied to an in vitro model of the intestinal barrier (monolayer of Caco-2 cells) to study GS15 NO intestinal permeability. RESULTS: A LC/ITMS/MS method based on an original transition (m/z 171 to 156) for sodium 15 N-nitrite, GS15 NO and sodium 15 N-nitrate measurements was validated, with recoveries of 100.8 ± 3.8, 98.0 ± 2.7 and 104.1 ± 3.3%, respectively. Intra- and inter-day variabilities were below 13.4 and 12.6%, and the limit of quantification reached 5 nM (signal over blank = 4). The permeability of labeled GS15 NO (10-100 µM) was evaluated by calculating its apparent permeability coefficient (Papp ). CONCLUSIONS: A quantitative LC/ITMS/MS method using HCD was developed for the first time to selectively monitor GS15 NO metabolites. The assay allowed evaluation of GS15 NO intestinal permeability and situated this drug candidate within the middle permeability class according to FDA guidelines. In addition, the present method has opened the perspective of a more fundamental work aiming at studying the fragmentation mechanism leading to the ion at m/z 156 in HCD tandem mass spectrometry in the presence of acetonitrile.

Intestinal absorption of S-nitrosothiols: Permeability and transport mechanisms.

S-Nitrosothiols, a class of NO donors, demonstrate potential benefits for cardiovascular diseases. Drugs for such chronic diseases require long term administration preferentially through the oral route. However, the absorption of S-nitrosothiols by the intestine, which is the first limiting barrier for their vascular bioavailability, is rarely evaluated. Using an in vitro model of intestinal barrier, based on human cells, the present work aimed at elucidating the mechanisms of intestinal transport (passive or active, paracellular or transcellular pathway) and at predicting the absorption site of three S-nitrosothiols: S-nitrosoglutathione (GSNO), S-nitroso-N-acetyl-l-cysteine (NACNO) and S-nitroso-N-acetyl-d-penicillamine (SNAP). These S-nitrosothiols include different skeletons carrying the nitroso group, which confer different physico-chemical characteristics and biological activities (antioxidant and anti-inflammatory). According to the values of apparent permeability coefficient, the three S-nitrosothiols belong to the medium class of permeability. The evaluation of the bidirectional apparent permeability demonstrated a passive diffusion of the three S-nitrosothiols. GSNO and NACNO preferentially cross the intestinal barrier though the transcellular pathway, while SNAP followed both the trans- and paracellular pathways. Finally, the permeability of NACNO was favoured at pH 6.4, which is close to the pH of the jejunal part of the intestine. Through this study, we determined the absorption mechanisms of S-nitrosothiols and postulated that they can be administrated through the oral route.

Glutathione: Antioxidant Properties Dedicated to Nanotechnologies.

Which scientist has never heard of glutathione (GSH)? This well-known low-molecular-weight tripeptide is perhaps the most famous natural antioxidant. However, the interest in GSH should not be restricted to its redox properties. This multidisciplinary review aims to bring out some lesser-known aspects of GSH, for example, as an emerging tool in nanotechnologies to achieve targeted drug delivery. After recalling the biochemistry of GSH, including its metabolism pathways and redox properties, its involvement in cellular redox homeostasis and signaling is described. Analytical methods for the dosage and localization of GSH or glutathiolated proteins are also covered. Finally, the various therapeutic strategies to replenish GSH stocks are discussed, in parallel with its use as an addressing molecule in drug delivery.

Highly sensitive and simple liquid chromatography assay with ion-pairing extraction and visible detection for quantification of gold from nanoparticles.

A simple isocratic HPLC method using visible detection was developed and validated for the quantification of gold in nanoparticles (AuNP). After a first step of oxidation of nanoparticles, an ion-pair between tetrachloroaurate anion and the cationic dye Rhodamine B was formed and extracted from the aqueous media with the help of an organic solvent. The corresponding Rhodamine B was finally quantified by reversed phase liquid chromatography using a Nucleosil C18 (150mm × 4.6mm, 3µm) column and with a mobile phase containing acetonitrile and 0.1% trifluoroacetic acid aqueous solution (25/75, V/V) at 1.0mLmin-1.and at a wavelength of 555nm. The method was validated using methodology described by the International Conference on Harmonization and was shown to be specific, precise (RSD < 11%), accurate and linear in the range of 0.1 - 30.0µM with a lower limit of quantification (LLOQ) of 0.1µM. This method was in a first time applied to AuNP quality control after their synthesis. In a second time, the absence of gold leakage (either as AuNP or gold salt form) from nanostructured multilayered polyelectrolyte films under shear stress was assessed.

Aging and hypertension decrease endothelial NO-related dilating function and gamma-glutamyl transferase activity but not S-nitrosoglutathione-induced aortic vasodilation.

S-nitrosoglutathione (GSNO), which is involved in the transport and the storage of NO, induces vasorelaxation. It requires gamma-glutamyl transferase (GGT), an enzyme present on the endothelium, to transfer NO into the cell. We evaluated whether aging and hypertension, which induce NO-related dilating dysfunction, are associated with decreased vascular GGT activity and modify the vasorelaxant effect of GSNO. Thoracic aortic rings isolated from male spontaneous hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) aged 20-22 (adult) or 57-60 weeks (mature) were preconstricted with phenylephrine, then submitted to concentration-vasorelaxant response curves (maximal response: Emax ; pD2 ) to GSNO and carbachol (the latter to measure NO-related dilating function). GGT activity was measured using chromogenic substrate. Both aging and hypertension lowered Emax values for carbachol (Emax -8% in adult SHR, -42% in mature SHR vs. age-matched WKY, page and phypertension  < 0.05) demonstrating NO-related dilating dysfunction. Aortic GGT activity also decreased with aging and hypertension (-22% in adult and -75%, reaching 3 nmol/min/g of tissue, in mature SHR vs. 12 in age-matched WKY and 23 in adult WKY, page and phypertension  < 0.05). The pD2 values of GSNO were similar in mature SHR and WKY but higher in adult SHR (pinteraction  < 0.05). Aging in hypertensive rats decreased NO-related vasorelaxant function and vascular GGT activity, but did not lower the vasorelaxant response to GSNO. This opens perspectives for GSNO-based therapeutics restoring nitric oxide bioavailability and vascular protection in a context of endothelial dysfunction.

Flush with a flash: natural three-component antimicrobial combinations based on S-nitrosothiols, controlled superoxide formation and "domino" reactions leading to peroxynitrite.

S-Nitrosothiols are ˙NO releasing agents renowned for vasodilatory and antioxidant properties. O2˙- promotes their decomposition, forming highly aggressive peroxynitrite ions (ONOO-). Since the production of O2˙- can be controlled by enzymes or by visible light, such otherwise harmless components can be turned into effective antimicrobial and nematicidal combinations with numerous potential applications in medicine.

In vivo and in silico evaluation of a new nitric oxide donor, S,S'-dinitrosobucillamine.

PURPOSE: In a previous work, we have synthetized a new dinitrosothiol, i.e. S,S'-dinitrosobucillamine BUC(NO)2 combining S-nitroso-N-acetylpenicillamine (SNAP) and S-nitroso-N-acetylcysteine (NACNO) in its structure. When exposed to isolated aorta, we observed a 1.5-fold increase of •NO content and a more potent vasorelaxation (1 log higher pD2) compared to NACNO and SNAP alone or combined (Dahboul et al., 2014). In the present study, we analyzed the thermodynamics and kinetics for the release of •NO through computational modeling techniques and correlated it to plasma assays. Then BUC(NO)2 was administered in vivo to rats, assuming it will induce higher and/or longer hypotensive effects than its two constitutive S-mononitrosothiols. METHODS: Free energies for the release of •NO entities have been computed at the density functional theory level assuming an implicit model for the aqueous environment. Degradation products of BUC(NO)2 were evaluated in vitro under heating and oxidizing conditions using HPLC coupled with tandem mass spectrometry (MS/MS). Plasma from rats were spiked with RSNO and kinetics of RSNO degradation was measured using the classical Griess-Saville method. Blood pressure was measured in awake male Wistar rats using telemetry (n = 5, each as its own control, 48 h wash-out periods between subcutaneous injections under transient isoflurane anesthesia, random order: 7 mL/kg vehicle, 3.5, 7, 14 µmol/kg SNAP, NACNO, BUC(NO)2 and an equimolar mixture of SNAP + NACNO in order to mimic the number of •NO contained in BUC(NO)2). Variations of mean (ΔMAP, reflecting arterial dilation) and pulse arterial pressures (ΔPAP, indirectly reflecting venodilation, used to determine effect duration) vs. baseline were recorded for 4 h. RESULTS: Computational modeling highlights the fact that the release of the first •NO radical in BUC(NO)2 requires a free energy which is intermediate between the values obtained for SNAP and NACNO. However, the release of the second •NO radical is significantly favored by the concerted formation of an intramolecular disulfide bond. The corresponding oxidized compound was also characterized as related substance obtained under degradation conditions. The in vitro degradation rate of BUC(NO)2 was significantly greater than for the other RSNO. For equivalent low and medium •NO-load, BUC(NO)2 produced a hypotension identical to NACNO, SNAP and the equimolar mixture of SNAP + NACNO, but its effect was greater at higher doses (-62 ± 8 and -47 ± 14 mmHg, maximum ΔMAP for BUC(NO)2 and SNAP + NACNO, respectively). Its duration of effect on PAP (-50%) lasted from 35 to 95 min, i.e. shorter than for the other RSNO (from 90 to 135 min for the mixture SNAP + NACNO). CONCLUSION: A faster metabolism explains the abilities of BUC(NO)2 to release higher amounts of •NO and to induce larger hypotension but shorter-lasting effects than those induced by the SNAP + NACNO mixture, despite an equivalent •NO-load.

Regulation of protein function by S-nitrosation and S-glutathionylation: processes and targets in cardiovascular pathophysiology.

Decades of chemical, biochemical and pathophysiological research have established the relevance of post-translational protein modifications induced by processes related to oxidative stress, with critical reflections on cellular signal transduction pathways. A great deal of the so-called 'redox regulation' of cell function is in fact mediated through reactions promoted by reactive oxygen and nitrogen species on more or less specific aminoacid residues in proteins, at various levels within the cell machinery. Modifications involving cysteine residues have received most attention, due to the critical roles they play in determining the structure/function correlates in proteins. The peculiar reactivity of these residues results in two major classes of modifications, with incorporation of NO moieties (S-nitrosation, leading to formation of protein S-nitrosothiols) or binding of low molecular weight thiols (S-thionylation, i.e. in particular S-glutathionylation, S-cysteinylglycinylation and S-cysteinylation). A wide array of proteins have been thus analyzed in detail as far as their susceptibility to either modification or both, and the resulting functional changes have been described in a number of experimental settings. The present review aims to provide an update of available knowledge in the field, with a special focus on the respective (sometimes competing and antagonistic) roles played by protein S-nitrosations and S-thionylations in biochemical and cellular processes specifically pertaining to pathogenesis of cardiovascular diseases.