Evolución del estado de nutrición de yodo en los escolares de la Comunidad Autónoma del País Vasco

BackgroundAn epidemiologic survey showed in 1992 iodine deficiency and endemic goiter in schoolchildren from the Basque Country.Objectives1) To determine the percentage of homes of schoolchildren where iodized salt (IS) is used; 2) to assess iodine nutrition status in schoolchildren and to compare the data collected to those available from previous epidemiological studies.Design and MethodsA cross-sectional study in 720 randomly selected schoolchildren. Urinary iodine concentration (UIC) was measured using high-performance liquid chromatography(HPLC) with electrochemical detection.ResultsIS was used at 53.0% of the homes (95% confidence interval [CI], 49.2-56.7%). Median UIC has increased by 226%, from 65 μg/L in 1992 to 147 μg/L (percentile [P], P₂₅, 99 μg/L; P₇₅, 233 μg/L) today. Both schoolchildren consuming IS and those using unfortified salt at their homes had UICs corresponding to adequate iodine intakes (165 and 132 μg/L respectively). UICs experienced great seasonal fluctuations, being 55% higher during the November-February period than in June-September period (191 μg/L vs 123 μg/L; p < 0.001)ConclusionsSchoolchildren from the Basque Country have normalized their iodine nutrition status. The strong seasonal pattern of UICs suggests that consumption of milk and iodine-rich dairy products coming from cows feed iodized fodder is one of the most significant factors involved in the increase in iodine intake since 1992.     

Inhibition of phospholipase A2 increases Tau phosphorylation at Ser214 in embryonic rat hippocampal neurons

BackgroundArachidonic acid is released from cellular membranes by the action of phospholipase A₂ (PLA₂) and is implicated in microtubule-associated protein Tau phosphorylation. Tau hyperphosphorylation affects its ability to stabilize microtubules.ObjectiveTo determine the effect of PLA₂ inhibition on the phosphorylation state of Tau phosphoepitopes in primary cultures of hippocampal neurons.Methods4 DIC neurons were incubated at different concentrations of methyl-arachidonylfluorophosphonate (MAFP), an irreversible inhibitor of cPLA₂ and iPLA₂. Changes on Tau phosphorylation were determined by Western blotting with a panel of anti-Tau antibodies (C-terminal, Ser199/202, Ser202/205, Ser396 and Ser214).ResultsThe Ser214 site was hyperphosphorylated upon MAFP treatment. Significant differences were observed with 10 μM (p=0.01), 50 μM (p=0.01) and 100 μM (p=0.05) of MAFP. Less-intense changes were found in other phosphoepitopes.ConclusionThe present findings indicate that the phosphorylation of Ser214 is regulated by c- and/or iPLA₂, whereas other phosphoepitopes primarily regulated by GKS3b were not affected.     

Ingesta de yodo durante el embarazo: efectos en la función tiroidea materna y neonatal

IntroductionRecent studies in Spain have shown an inadequate iodine intake in a significant proportion of pregnant women. Pregnancy increases thyroid hormone requirements, and adequate iodine intake is therefore needed.Material and methodsOne hundred and forty-seven women in their third trimester (week 37) of pregnancy provided a blood sample and a 24-hour urine sample to test serum and urine iodine levels and completed a food frequency questionnaire to assess iodine intake during pregnancy. Serum TSH levels were measured in the babies born to the 140 mothers in the postpartum group.ResultsOnly 10.9% of pregnant women consumed more than 250 μg iodine daily, and 24.4% of them consumed less than 100 μg daily. Mean free T4 levels were 9.37 pmol/L, and 74 women (54.41%) had levels below the hypothyroxinemia threshold. TSH levels were normal in 135 newborns (96.4%), while 5 (3.6%) had levels higher than 5 μU/mL.     

Nutrición de yodo en mujeres embarazadas del área de Oviedo. ¿Es necesaria la suplementación con yodo?

Background and objectiveIn Asturias, where iodine deficiency was eradicated in school children by the year 2000, iodine deficiency persisted in pregnant women, who were recommended to use of iodine supplementation. The aim of this study was to determine the iodine nutrition of pregnant women in our area and whether or not iodine supplements are needed.Material and methodsThroughout May and June 2013 we studied the iodine nutrition and thyroid function during the first trimester of pregnancy in 173 women in the health area of Oviedo.ResultsThe median urinary iodine was 197 μg/L. Iodinated supplements were used by 47% of women, which had a yoduria median higher than those not taking iodinated supplements (247 vs. 138 μg/L; p < .001), and also a higher TSH (2.30 vs 1.94 mU/L) although not significantly different. Yoduria was also higher in women who took more than 2 servings of dairy products (median: 230 μg/L) than those who took less (median: 191 μg/L). Within the group of women who were not taking iodine supplements, those regularly using iodized salt in the kitchen (47%) had a median urinary iodine concentration of 190 μg/L indicating iodine sufficiency.ConclusionsIodinated supplements seem unnecessary nowadays in pregnant women of Oviedo who regularly take iodized salt and our recommendation in these cases should be to continue the use of iodized salt in the recommended amounts during pregnancy and consume at least two daily servings of milk or dairy products.     

Design and synthesis of γ-butyrolactone derivatives as potential spermicidal agents

A series of γ-butyrolactone derivatives has been designed and synthesized from commercially available 2-acetyl butyrolactone (3-acetyldihydrofuran-2(3H)-one, 1) by aminoalkylating its active methylene followed by condensation with different aldehydes. Compounds having amino group were further converted to their respective tartrate salts and were evaluated for spermicidal activity against human sperm in vitro. Compounds showing appreciable spermicidal activity at ⩽0.5% [3c, 4d (0.5%); 2c, 3d (0.1%); 2d, 4c (0.05%)] were tested for safety studies against human cervical (HeLa) cell line. These compounds were found safer than, Nonoxynol-9. One of the two most active compounds was also found to be the safest (IC₅₀ = 961 μg/ml; 4c), while the second compound exhibited lower safety against HeLa (IC₅₀ = 269 μg/ml; 2d). The compound 4c significantly reduced the number of free thiols on human sperm. All the compounds were inactive against Trichomonas vaginalis.     

Design,synthesis and evaluation of 2,4-disubstituted pyrimidines as cholinesterase inhibitors

A group of 2,4-disubstituted pyrimidine derivatives (7a–e, 8a–e and 9a–d) that possess a variety of C-2 aliphatic five- and six-membered heterocycloalkyl ring in conjunction with a C-4 arylalkylamino substituent were designed, synthesized and evaluated as cholinesterase (ChE) inhibitors. The steric and electronic properties at C-2 and C-4 positions of the pyrimidine ring were varied to investigate their effect on ChE inhibitory potency and selectivity. The structure–activity relationship (SAR) studies identified N-benzyl-2-thiomorpholinopyrimidin-4-amine (7c) as the most potent cholinesterase inhibitor (ChEI) with an IC₅₀ = 0.33 μM (acetylcholinesterase, AChE) and 2.30 μM (butyrylcholinesterase, BuChE). The molecular modeling studies indicate that within the AChE active site, the C-2 thiomorpholine substituent was oriented toward the cationic active site region (Trp84 and Phe330) whereas within the BuChE active site, it was oriented toward a hydrophobic region closer to the active site gorge entrance (Ala277). Accordingly, steric and electronic properties at the C-2 position of the pyrimidine ring play a critical role in ChE inhibition.     

Structural–functional insights of single and multi-domain Capsicum annuum protease inhibitors

Pin-II protease inhibitors (PIs) are the focus of research interest because of their large structural–functional diversity and relevance in plant defense. Two representative Capsicum annuum PI genes (CanPI-15 and -7) comprising one and four inhibitory repeat domains, respectively, were expressed and recombinant proteins were characterized. β-Sheet and unordered structure was found predominant in CanPI-15 while -7 also displayed the signatures of polyproline fold, as revealed by circular dichroism studies. Inhibition kinetics against bovine trypsin indicated three times higher potency of CanPI-7 (K_i ～ 57 μM) than -15 (～184 μM). Activity and structural stability of these CanPIs were revealed under various conditions of pH, temperature and denaturing agent. Structure prediction, docking studies with proteases and mass spectroscopy revealed the organization of multiple reactive site loops of multi domain PIs in space as well as the steric hindrances imposed while binding to proteases due to their close proximity.     

Potent and selective HIV-1 ribonuclease H inhibitors based on a 1-hydroxy-1,8-naphthyridin-2(1H)-one scaffold

Optimization studies using an HIV RNase H active site inhibitor containing a 1-hydroxy-1,8-naphthyridin-2(1H)-one core identified 4-position substituents that provided several potent and selective inhibitors. The best compound was potent and selective in biochemical assays (IC₅₀ = 0.045 μM, HIV RT RNase H; 13 μM, HIV RT-polymerase; 24 μM, HIV integrase) and showed antiviral efficacy in a single-cycle viral replication assay in P4-2 cells (IC₅₀ = 0.19 μM) with a modest window with respect to cytotoxicity (CC₅₀ = 3.3 μM).     

Urinary iodine and thyroid function in a population of healthy pregnant women in the North of Spain

BackgroundIodine is an essential trace element for the synthesis of thyroid hormones, which are keys in maternal metabolism during pregnancy as well as in neurological development during fetal and postnatal life. This was a prospective study on iodine status and thyroid function in women during pregnancy in the Basque country to assess whether there was any relationship among maternal urinary iodine, maternal thyroid function and thyrotropin (TSH) in newborns, and to explore any difference in women experiencing miscarriages.MethodsWe analyzed TSH, free T₄ (FT₄), free T₃ (FT₃), thyroid peroxidase antibody (TPO-Ab) titers in serum and urinary iodine concentrations (UIC) in 2104 women in the first trimester of pregnancy and in 1322 of them in their second trimester. We obtained neonatal TSH levels in 1868 cases.ResultsIn the first (T1) and second trimesters (T2), the median UICs were 88.5 μg/L and 140 μg/L, respectively. No relationship was found between UIC and FT₄, or maternal and neonatal TSH. In T1 and T2, 9.7% and 7.5% of women were TPO-Ab positive, respectively. The total miscarriage rate was 10%. The percentage of miscarriages in healthy women was 8.9%, lower than in women with overt hypothyroidism (21.2%; p < 0.001) and than in women with subclinical hypothyroidism (15.6%; p < 0.025). The miscarriage rate was not higher in TPO-Ab-positive women.ConclusionsIn this study most women had iodine deficiency during pregnancy. Neonatal TSH is not correlated with maternal UIC during pregnancy. Pregnant women with hypothyroidism have a higher rate of miscarriages.     

Excess iodinuria in infants and its relation to the iodine in maternal milk

ObjectiveIodine is an essential micro nutrient, and a deficiency or excessive intake of this mineral is related to changes in thyroid function. In Brazil, both deficiency and excessive intake of iodine are common; however, excessive intakes have recently been observed. Thus, the objective of the present study was to assess the iodine concentration in maternal milk, taking into account the salt iodine concentration of the participating households and in the infants’ urine.MethodUrine samples from 33 infants (less than 6 months of age), maternal milk samples and samples of the kitchen salt used by the mothers were collected. The iodine levels in the urine and maternal milk were assessed by ICP-MS; the iodine levels in the salt were assessed by titration.ResultThe median iodinuria value in the infants was 293 μg/L; the mean iodine concentration was 206 μg/L in the maternal milk and 39.9 mg I/kg in the salt. There was a positive correlation between the iodine concentration in the maternal milk and the infant iodinuria value.ConclusionThe median infant iodinuria was elevated due to the high iodine concentration present in the maternal milk. High iodine values were caused by high salt iodine levels, which should be reduced.     

Structural basis for the magnesium-dependent activation of transketolase from Chlamydomonas reinhardtii

BackgroundIn photosynthetic organisms, transketolase (TK) is involved in the Calvin-Benson cycle and participates to the regeneration of ribulose-5-phosphate. Previous studies demonstrated that TK catalysis is strictly dependent on thiamine pyrophosphate (TPP) and divalent ions such as Mg^2 +.MethodsTK from the unicellular green alga Chlamydomonas reinhardtii (CrTK) was recombinantly produced and purified to homogeneity. Biochemical properties of the CrTK enzyme were delineated by activity assays and its structural features determined by CD analysis and X-ray crystallography.ResultsCrTK is homodimeric and its catalysis depends on the reconstitution of the holo-enzyme in the presence of both TPP and Mg^2 +. Activity measurements and CD analysis revealed that the formation of fully active holo-CrTK is Mg^2 +-dependent and proceeds with a slow kinetics. The 3D–structure of CrTK without cofactors (CrTK_apo) shows that two portions of the active site are flexible and disordered while they adopt an ordered conformation in the holo-form. Oxidative treatments revealed that Mg^2 + participates in the redox control of CrTK by changing its propensity to be inactivated by oxidation. Indeed, the activity of holo-form is unaffected by oxidation whereas CrTK in the apo-form or reconstituted with the sole TPP show a strong sensitivity to oxidative inactivation.ConclusionThese evidences indicate that Mg^2 + is fundamental to allow gradual conformational arrangements suited for optimal catalysis. Moreover, Mg^2 + is involved in the control of redox sensitivity of CrTK.General significanceThe importance of Mg^2 + in the functionality and redox sensitivity of CrTK is correlated to light-dependent fluctuations of Mg^2 + in chloroplasts.     

5-Nitro-2-furoic acid hydrazones: Design,synthesis and in vitro antimycobacterial evaluation against log and starved phase cultures

Various 5-nitro-2-furoic acid hydrazones were synthesized and evaluated for in vitro activities against log and starved phase culture of two mycobacterial species and Mycobacterium tuberculosis (MTB) isocitrate lyase (ICL) enzyme inhibition studies. Among twenty one compounds, 5-nitro-N′-[(5-nitro-2-furyl)methylidene]-2-furohydrazide (4o) was found to be the most active compound in vitro with MICs of 2.65 and 10.64 μM against log- and starved-phase culture of MTB. Compound 4o also showed good enzyme inhibition of MTB ICL at 10 μM. The docking studies also confirmed the binding potential of the compounds at the ICL active site.     

Ebselen and analogs as inhibitors of Bacillus anthracis thioredoxin reductase and bactericidal antibacterials targeting Bacillus species,Staphylococcus aureus and Mycobacterium tuberculosis

BackgroundBacillus anthracis is the causative agent of anthrax, a disease associated with a very high mortality rate in its invasive forms.MethodsWe studied a number of ebselen analogs as inhibitors of B. anthracis thioredoxin reductase and their antibacterial activity on Bacillus subtilis, Staphylococcus aureus, Bacillus cereus and Mycobacterium tuberculosis.ResultsThe most potent compounds in the series gave IC50 values down to 70 nM for the pure enzyme and minimal inhibitory concentrations (MICs) down to 0.4 μM (0.12 μg/ml) for B. subtilis, 1.5 μM (0.64 μg/ml) for S. aureus, 2 μM (0.86 μg/ml) for B. cereus and 10 μg/ml for M. tuberculosis. Minimal bactericidal concentrations (MBCs) were found at 1–1.5 times the MIC, indicating a general, class-dependent, bactericidal mode of action. The combined bacteriological and enzymological data were used to construct a preliminary structure–activity-relationship for the benzoisoselenazol class of compounds. When S. aureus and B. subtilis were exposed to ebselen, we were unable to isolate resistant mutants on both solid and in liquid medium suggesting a high resistance barrier.ConclusionsThese results suggest that ebselen and analogs thereof could be developed into a novel antibiotic class, useful for the treatment of infections caused by B. anthracis, S. aureus, M. tuberculosis and other clinically important bacteria. Furthermore, the high barrier against resistance development is encouraging for further drug development.General significanceWe have characterized the thioredoxin system from B. anthracis as a novel drug target and ebselen and analogs thereof as a potential new class of antibiotics targeting several important human pathogens.     

Structure–activity studies of echinomycin antibiotics against drug-resistant and biofilm-forming Staphylococcus aureus and Enterococcus faecalis

Four echinomycin antibiotics were isolated from the culture broth of a marine streptomycete, and their structures were determined by a combination of chemical and spectroscopic analyses. Antibiotic activities were measured against drug-resistant and biofilm-forming strains of Staphylococcus aureus and Enterococcus faecalis. Minimum inhibitory concentrations ranging from 0.01 μM to greater than 14 μM clearly defined structure–activity relationships for antibiotic potency. Echinomycin was the most active compound with a MIC of 0.03 μM against methicillin-resistant S. aureus and 0.01 μM against biofilm-forming E. faecalis.     

Design and biological testing of peptidic dimerization inhibitors of human Hsp90 that target the C-terminal domain

BackgroundSmall molecules targeting the dimerization interface of the C-terminal domain of Hsp90, a validated target for cancer treatment, have yet to be identified.MethodsThree peptides were designed with the aim to inhibit the dimerization of Hsp90. Computational and biophysical methods examined the α-helical structure for the three peptides. Based on the Autodisplay technology, a novel flow cytometer dimerization assay was developed to test inhibition of Hsp90 dimerization. Microscale thermophoresis was used to determine the K_D of the peptides towards the C-terminal domain of Hsp90.ResultsMD simulations and CD spectroscopy indicated an α-helical structure for two of the three peptides. By flow cytometer analysis, IC₅₀ values of 2.08 μM for peptide H2 and 8.96 μM for peptide H3 were determined. Dimer formation of the C-terminal dimerization domain was analyzed by microscale thermophoresis, and a K_D of 1.29 nM was determined. Furthermore, microscale thermophoresis studies demonstrated a high affinity binding of H2 and H3 to the C-terminal domain, with a K_D of 1.02 μM and 1.46 μM, respectively.ConclusionsThese results revealed the first peptidic inhibitors of Hsp90 dimerization targeting the C-terminal domain. Furthermore, it has been shown that these peptides bind to the C-terminal domain with a low micromolar affinity.General significanceThese results can be used to design and screen for small molecules that inhibit the dimerization of the C-terminal domain of Hsp90, which could open a new route for cancer therapy.     

Characterization of the N-oxygenase AurF from Streptomyces thioletus

AurF catalyzes the N-oxidation of p-aminobenzoic acid to p-nitrobenzoic acid in the biosynthesis of the antibiotic aureothin. Here we report the characterization of AurF under optimized conditions to explore its potential use in biocatalysis. The pH optimum of the enzyme was established to be 5.5 using phenazine methosulfate (PMS)/NADH as the enzyme mediator system, showing ∼10-fold higher activity than previous reports in literature. Kinetic characterization at optimized conditions give a K_m of 14.7 ± 1.1 μM, a k_cat of 47.5 ± 5.4 min⁻¹ and a k_cat/K_m of 3.2 ± 0.4 μM⁻¹ min⁻¹. PMS/NADH and the native electron transfer proteins showed significant formation of the p-hydroxylaminobenzoic acid intermediate, however H₂O₂ produced mostly p-nitrobenzoic acid. Alanine scanning identified the role of important active site residues. The substrate specificity of AurF was examined and rationalized based on the protein crystal structure. Kinetic studies indicate that the K_m is the main determinant of AurF activity toward alternative substrates.     

3-Aryl-4-acyloxyethoxyfuran-2(5H)-ones as inhibitors of tyrosyl-tRNA synthetase: Synthesis,molecular docking and antibacterial evaluation

Thirty-eight 3-aryl-4-acyloxyethoxyfuran-2(5H)-ones were designed, prepared and tested for antibacterial activities. Some of them showed significant antibacterial activity against Gram-positive organism, Gram-negative organism and fungus. Out of these compounds, 4-(2-(3-chlorophenylformyloxy)ethoxy)-3-(4-chlorophenyl)furan-2(5H)-one (d40) showed the widest spectrum of activity with MIC₅₀ of 2.0 μg/mL against Staphylococcus aureus, 4.3 μg/mL against Escherichia coli, 1.5 μg/mL against Pseudomonas aeruginosa and 1.2 μg/mL against Candida albicans. Our data disclosed that MIC₅₀ values against whole cell bacteria are positive correlation with MIC₅₀ values against tyrosyl-tRNA synthetase. Meanwhile, molecular docking of d40 into S. aureus tyrosyl-tRNA synthetase active site was also performed, and the inhibitor tightly fitting the active site might be an important reason why it has high antimicrobial activity.     

Highly potent tyrosinase inhibitor,neorauflavane from Campylotropis hirtella and inhibitory mechanism with molecular docking

Tyrosinase inhibition may be a means to alleviate not only skin hyperpigmentation but also neurodegeneration associated with Parkinson’s disease. In the course of metabolite analysis from tyrosinase inhibitory methanol extract (80% inhibition at 20 μg/ml) of Campylotropis hirtella, we isolated fourteen phenolic compounds, among which neorauflavane 3 emerged as a lead structure for tyrosinase inhibition. Neorauflavane 3 inhibited tyrosinase monophenolase activity with an IC₅₀ of 30 nM. Thus this compound is 400-fold more active than kojic acid. It also inhibited diphenolase (IC₅₀ = 500 nM), significantly. Another potent inhibitor 1 (IC₅₀ = 2.9 μM) was found to be the most abundant metabolite in C. hirtella. In kinetic studies, compounds 3 showed competitive inhibitory behavior against both monophenolase and diphenolase. It manifested simple reversible slow-binding inhibition against monophenolase with the following kinetic parameters: K_i^app = 1.48 nM, k₃ = 0.0033 nM⁻¹ min⁻¹ and k₄ = 0.0049 min⁻¹. Neorauflavane 3 efficiently reduced melanin content in B16 melanoma cells with 12.95 μM of IC₅₀. To develop a pharmacophore model, we explored the binding mode of neuroflavane 3 in the active site of tyrosinase. Docking results show that resorcinol motif of B-ring and methoxy group in A-ring play crucial roles in the binding the enzyme.     

Design,synthesis and biological evaluation of novel donepezil–coumarin hybrids as multi-target agents for the treatment of Alzheimer’s disease

Combining N-benzylpiperidine moiety of donepezil and coumarin into in a single molecule, novel hybrids with ChE and MAO-B inhibitory activity were designed and synthesized. The biological screening results indicated that most of compounds displayed potent inhibitory activity for AChE and BuChE, and clearly selective inhibition to MAO-B. Of these compounds, 5m was the most potent inhibitor for eeAChE and eqBuChE (0.87 μM and 0.93 μM, respectively), and it was also a good and balanced inhibitor to hChEs and hMAO-B (1.37 μM for hAChE; 1.98 μM for hBuChE; 2.62 μM for hMAO-B). Molecular modeling and kinetic studies revealed that 5m was a mixed-type inhibitor, which bond simultaneously to CAS, PAS and mid-gorge site of AChE, and it was also a competitive inhibitor, which occupied the active site of MAO-B. In addition, 5m showed good ability to cross the BBB and had no toxicity on SH-SY5Y neuroblastoma cells. Collectively, all these results suggested that 5m might be a promising multi-target lead candidate worthy of further pursuit.     

Primer caso de fungemia asociada a catéter por Candida nivariensis en la Península Ibérica

BackgroundIn recent years the incidence of candidemia caused by non-albicans Candida species has been increasing. Two cryptic species have been described within the Candida glabrata complex, Candida nivariensis and Candida bracarensis, which may be troublesome in laboratory identification and have lower susceptibility to fluconazole.AimsTo describe the first isolation of C. nivariensis in the Iberian Peninsula from a patient suffering from a catheter-related fungemia.Case reportAn 81-year-old man was hospitalized for surgical treatment of an intestinal fistula that was associated to a severe malnutrition. Cultures of the patient's central venous catheter tip and blood yielded white colonies in BD CHROMagar Candida^® medium, which could not be identified by conventional microbiological methods. Although intravenous fluconazole was administered, blood cultures continued being positive 5 days later. The MIC values of the isolate were as follows: 1 μg/ml for amphotericin B, 0.015 μg/ml for anidulafungin, 0.125 μg/ml for caspofungin, 0.015 μg/ml for micafungin, 4 μg/ml for fluconazole, 0.25 μg/ml for itraconazole, 0.25 μg/ml for posaconazole, and 0.03 μg/ml for voriconazole. Antifungal treatment was changed to intravenous caspofungin for 2 weeks. The intestinal fistula was surgically treated. There was no evidence of relapse during the following month, and the patient was discharged. The isolate was identified as C. nivariensis based on DNA sequencing of the ITS regions of rRNA.ConclusionsC. nivariensis should be regarded as an emerging pathogen which requires molecular methods for a definitive identification. Our patient was successfully treated with caspofungin.