Pretreatment HIV-1 drug resistance in Argentina: results from a surveillance study performed according to WHO-proposed new methodology in 2014-15.

BACKGROUND: In Argentina, current national guidelines recommend starting with NNRTI-based regimens. Recently, there have been some local reports regarding concerning levels of NNRTI-transmitted resistance, but surveillance has never been carried out at a national level. OBJECTIVES: To determine the prevalence of HIV drug resistance in people starting ART in Argentina using a WHO-proposed methodology. METHODS: This was a cross-sectional, nationally representative study. Twenty-five antiretroviral-dispensing sites throughout the country were randomly chosen to enrol at least 330 persons starting ART, to generate a point prevalence estimate of resistance-associated mutations (RAMs) with a 5% CI (for the total population and for those without antiretroviral exposure). All consecutive patients older than 18 years starting or restarting ART in the chosen clinics were eligible. Samples were processed with Trugene and analysed using the Stanford algorithm. RESULTS: Between August 2014 and March 2015, we obtained 330 samples from people starting ART. The mean ±â€ŠSD age was 35 ±â€Š11 years, 63.4% were male, 16.6% had prior antiretroviral exposure and the median (IQR) CD4 count was 275 cells/mm3 (106-461). The prevalence of RAMs found was 14% (±4%) for the whole population (3% NRTI-RAMs; 11% NNRTI-RAMs and 2% PI-RAMs) and 13% (±4%) for those without prior antiretroviral exposure (3%, 10% and 2%, respectively). The most common mutation was K103N. CONCLUSIONS: This surveillance study showed concerning levels of HIV drug resistance in Argentina, especially to NNRTIs. Due to this finding, Argentina's Ministry of Health guidelines will change, recommending performing a resistance test for everyone before starting ART. If this is taken up properly, it also might function as a continuing surveillance tool.

Influence of antidepressant drugs on Ecto-nucleotide pyrophosphatase/phosphodiesterases (E-NPPs) from salivary glands of rats.

Xerostomia is commonly caused by antidepressant drugs and ATP can influence the saliva production. Adenosine is the product of extracellular hydrolysis of adenine nucleotides in submandibular gland cells, which occurs by the action of ectonucleotidases. In this study, we have evaluated the effect of three different antidepressants in ecto-nucleotide pyrophosphatase/phosphodiesterase (E-NPP1-3) activities in cultured cells from salivary glands. Rats received imipramine (10mg/ml), fluoxetine (20mg/ml) or moclobemide (30mg/ml) by oral gavage. The drugs were administered once a day for 14 days. Our results have shown that the hydrolysis of p-nitrophenyl-5'-thymidine monophosphate increased in all treatments. These effects were not consequence of transcriptional control of E-NPP1-3 genes. The results reported here can highlight the importance of ectonucleotidases in the most common side effect caused by antidepressant therapy.

The effects of angiotensin II and genetic hypertension upon extracellular nucleotide hydrolysis by rat platelet ectoenzymes.

The extracellular nucleotides, ATP and ADP, as well as adenosine have been implicated in a great number of physiological functions. ADP is one of the major platelet recruiting factors, whereas ATP is considered to be a competitive inhibitor of ADP-induced platelet aggregation and adenosine is able to induce vasodilatation and to inhibit platelet aggregation. The di- and triphosphate nucleosides can be hydrolyzed by members of several families of ectonucleotidases, including ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases) and ecto-nucleotide pyrophosphatase/phosphodiesterases (E-NPPs) that, together with an ecto-5'-nucleotidase, catalyze adenosine formation. The renin-angiotensin system is the most important regulator of renal and cardiovascular functions and angiotensin II induces, physiologically, platelet activation. The aim of this study was to clarify the effects of ANGII and genetic hypertension upon extracellular nucleotide hydrolysis by rat platelet ectoenzymes. ANGII, in all tested doses (5, 50, 500 and 5000 pmol), was able to increase ATP (21, 31, 44 and 27%, respectively), ADP (22, 28, 78 and 37%, respectively) and AMP (40, 64, 60 and 64%, respectively) hydrolysis by rat platelets. Furthermore, losartan, a specific antagonist of the AT1 angiotensin-receptor, prevented the nucleotide hydrolysis effects. Additionally, an increase in AMP (about 144%) hydrolysis and a decrease in p-Nph-5'TMP (about 27%) hydrolysis were observed in platelets from spontaneously hypertensive rats (SHR) when compared to Wistar normotensive rats. We, herein, present data to demonstrate interactions between rat platelet angiotensinergic and adenosinergic systems that could contribute to the understanding and treatment of cardiovascular diseases such as hypertension, thrombosis and arteriosclerosis.

Ecto-nucleotide pyrophosphatase/phosphodiesterase as part of a multiple system for nucleotide hydrolysis by platelets from rats: kinetic characterization and biochemical properties.

In this study, we describe an ecto-nucleotide pyrophosphatase/phosphodiesterase (E-NPP) activity in rat platelets. Using p-nitrophenyl 5'-thymidine monophosphate (p-Nph-5'-TMP) as a substrate for E-NPP, we demonstrate an enzyme activity that shares the major biochemical properties described for E-NPPs: alkaline pH dependence, divalent cation dependence and blockade of activity by metal ion chelator. K(m) and V(max) values for p-Nph-5'-TMP hydrolysis were found to be 106 +/- 18 microM and 3.44 +/- 0.18 nmol p-nitrophenol/min/mg (mean +/- SD, n = 5). We hypothesize that an E-NPP is co-localized with an ecto-nucleoside triphosphate diphosphohydrolase and an ecto-5'-nucleotidase on the platelet surface, as part of a multiple system for nucleotide hydrolysis, since they can act under distinct physiological conditions and can be differently regulated. Thus, 0.25 mM suramin inhibited p-Nph-5'-TMP, ATP and ADP hydrolysis, while 0.5 mM AMP decreased only p-Nph-5'-TMP hydrolysis. Besides, 5.0, 10 and 20 mM sodium azide just inhibited ATP and ADP hydrolysis. Angiotensin II (5.0 and 10 nM) affected only ADP hydrolysis. Gadolinium chloride (0.2 and 0.5 mM) strongly inhibited the ATP and ADP hydrolysis. The E-NPP described here represents a novel insight into the control of platelet purinergic signaling.