Influence of nutritional status on clinical outcomes among hospitalized patients with COVID-19

BACKGROUND AND AIMS

Several factors that worsen the prognosis of the new coronavirus SARS-CoV-2 have been identified, such as obesity or diabetes. However, despite that nutrition may change in a lockdown situation, little is known about the influence of malnutrition among subjects hospitalized due to COVID-19. Our study aimed to assess whether the presence of malnutrition among patients admitted due to COVID-19 had any impact on clinical outcomes compared with patients with the same condition but well nourished.

METHODS

75 patients admitted to hospital due to COVID-19 were analyzed cross-sectionally. Subjective Global Assessment (SGA) was completed by phone interview. Clinical parameters included were extracted from the electronic medical record.

RESULTS

According to the SGA, 27 admitted due to a COVID-19 infection had malnutrition. Patients not well nourished were older than patients with a SGA grade A (65 ± 14.1 vs 49 ± 15.1 years; p < 0.0001). Length of hospital stay among poorly nourished patients was significantly higher (18.4 ± 15.6 vs 8.5 ± 7.7 days; p = 0.001). Mortality rates and admission to ICU were greater among subjects with any degree of malnutrition compared with well-nourished patients (7.4% vs 0%; p = 0.05 and 44.4% vs 6.3%; p < 0.0001). CRP (120.9 ± 106.2 vs 60.8 ± 62.9 mg/l; p = 0.03), D-dimer (1516.9 ± 1466.9 vs 461.1 ± 353.7 ng/mL; p < 0.0001) and ferritin (847.8 ± 741.1 vs 617.8 ± 598.7mcg/l; p = 0.03) were higher in the group with malnutrition. Haemoglobin (11.6 ± 2.1 vs 13.6 ± 1.5 g/dl; p < 0.0001) and albumin 3.2 ± 0.7 vs 4.1 ± 0.5 g/dl; p < 0.0001) were lower in patients with any degree of malnutrition.

CONCLUSIONS

The presence of a poor nutritional status is related to a longer stay in hospital, a greater admission in the ICU and a higher mortality.

The effects of chronic back pain on self-management, clinical and psychological outcomes among patients with type 2 diabetes

BACKGROUND

Chronic back pain (CBP) in patients with type 2 diabetes (T2DM) is twice as high among age-and-gender-matched controls. The presence of both conditions impacts negatively on both quality of life and physical function, which might negatively affect mood.

METHODS

We aimed to determine the prevalence of CBP among patients with T2DM by using the Lattinen Index (LI) and to assess whether the presence of CBP had any influence on clinical or psychological outcomes.

RESULTS

13.5% out of 299 patients had significant CBP. The percentage of patients with less than 150 minutes per 1 week of exercise was higher in the group of patients with significant CBP (70% vs 51.4%; p= 0.04). The proportion of patients who met criteria for food addiction was greater among subjects with CBP (47.5% vs 26.6%; p=0.009). The percentage of patients with criteria for depression was higher among the CBP group (82.5% vs 29.7%; p<0.0001), as well as the prescription of antidepressants (45% vs 17.4%; p<0.0001). However, no significant differences were seen regarding glycemic control or the frequency of complications related to T2DM.

CONCLUSIONS

CBP is prevalent among subjects with T2DM and it constitutes an important limiting factor of both self-care behaviors and psychological well-being.

Supercritical fluid chromatography-mass spectrometric determination of chiral fungicides in viticulture-related samples

Supercritical fluid chromatography (SFC), combined with mass spectrometry (MS), was employed for the determination of five chiral fungicides, from two different chemical families (acylalanine and triazol) in wine and vineyard soils. The effect of different SFC parameters (stationary phase, chiral selector, mobile phase modifier and additive) in the resolution between enantiomers and in the efficiency of compounds ionization at the electrospray source (ESI) was thorougly described. Under final working conditions, chiral separations of selected fungicides were achieved using two different SFC-MS methods, with an analysis time of 10 min and resolution factors from 1.05 to 2.45 between enantiomers. In combination with solid-phase extraction and pressurized liquid extraction, they permitted the enantiomeric determination of target compounds in wine and vineyard soils with limits of quantification in the low ppb range (between 0.5 and 2.5 ng mL^-1, and from 1.3 to 6.5 ng g^-1, for wine and soil, respectively), and overall recoveries above 80%, calculated using solvent-based standards. For azolic fungicides (tebuconazole, myclobutanil and penconazole) soil dissipation and transfer from vines to wines were non-enantioselective processes. Data obtained for acylalanine compounds confirmed the application of metalaxyl (MET) to vines as racemate and as the R-enantiomer. The enantiomeric fractions (MET-S/(MET-S+MET-R)) of this fungicide in vineyard soils varied from 0.01 to 0.96; moreover, laboratory degradation experiments showed that the relative dissipation rates of MET enantiomers varied depending on the type of soil.

Assessment of UV combined with free chlorine for removal of valsartan acid from water samples

Valsartan acid (VALA) is a persistent and mobile pollutant, ubiquitously distributed in the aquatic environment. Herein, we assessed the efficiency of UV/free chlorine for the removal of this pollutant. Degradation experiments were performed using different water samples, considering several pH values and concentrations of inorganic anions. Time-course of VALA was measured by injection of different reaction time aliquots in a liquid chromatography (LC) triple quadrupole (QqQ) mass spectrometry (MS) system, whilst the study of potential transformation products (TPs) was evaluated by LC combined with a hybrid quadrupole time-of-flight (QTOF) MS system. Formation of volatile disinfection by-products (DBPs) was investigated by gas chromatography (GC) with TOF-MS detection. Compared to free chlorine treatment and UV photolysis, the combination of both parameters significantly enhanced the degradability of VALA. At neutral pH, UV/free chlorine was also more effective than UV/H₂O₂ to remove VALA from spiked water solutions. Three TPs of VALA were tentatively identified by LC-QTOF-MS, although only one was stable in the UV/free chlorine media. As regards volatile DBPs, the formation of chloroform, dichloroacetonitrile, di- and trichloroacetic acid was noticed. The mass yield of DBPs formation from VALA varied from 0.3% (dichloroacetonitrile) to 1.1% (chloroform). The efficiency of UV/free chlorine was first investigated in spiked solutions with increasing complexities: ultrapure, river and treated wastewater. Thereafter, the feasibility of reducing VALA levels in polluted river water was demonstrated.

Long-Term Prevalence of Food Addiction Among Bariatric Surgery Patients: Influence on Metabolic and Psychological Outcomes

Background: We wanted to assess the prevalence of individuals with food addiction (FA) among bariatric surgery (BS) patients at long term and to determine if there was any relationship between FA and both clinical and psychological outcomes at the time of the evaluation. Methods: Participants were evaluated for the presence of FA with the Yale Food Addiction Scale 2.0. Results: Of 134 subjects, 32 (23.9%) included met criteria for FA. The frequency of patients with depression at the time of the evaluation was greater among subjects with FA (34.4% vs. 11.8%; P = 0.006). The score obtained with the Beck Depression Inventory at the time of the evaluation was greater among subjects with FA (14.8 ± 11.5 vs. 6 ± 6.5; P < 0.0001). The frequency of subjects with FA who had criteria for binge eating disorder at the time of the evaluation was significantly greater (56.3% vs. 20.5%; P < 0.001). Patients with FA scored higher in the Lattinen index for chronic pain at the time of the evaluation (8.7 ± 5.9 vs. 5.8 ± 5.4; P = 0.014). However, clinical outcomes were similar between the two groups. Conclusions: Routine screening for FA at long term postoperatively should be recommended to improve psychological outcomes of BS.

Multiresidue procedure to assess the occurrence and dissipation of fungicides and insecticides in vineyard soils from Northwest Spain

The presence of fungicide and insecticide residues in wine has been largely investigated. However, few studies have addressed the persistence of these compounds in vineyard soils. In this research, we investigate the residues of a relevant number of fungicides and insecticides in vineyard soils, obtained in the Northwest of Spain, at the beginning of each agriculture campaign. Moreover, the dissipation of species showing high concentrations were monitored during the non-vegetative period of vines, in order to understand their soil evolution between application campaigns. To this end, a multiresidue analytical procedure based on pressurized liquid extraction (PLE) followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) determination was first optimized. Under final working conditions, absolute recoveries in the range from 70 to 130% were achieved for 44 out of 51 selected compounds. The method LOQs remained at the low ng g^-1 level (0.2-13 ng g^-1) with a linear response range up to 500 ng g^-1. Analysis of vineyard soils, collected during a 2-year period, from a geographic area with a high incidence of fungal diseases, demonstrated the presence of relevant concentrations of several fungicides and the insecticide imidacloprid (IMI) in this compartment. Most compounds detected at the end of the application season remained in soil at the beginning of the next year campaign. Among them, six fungicides (dimethomorph, boscalid, myclobutanil, penconazole, pyraclostrobin and pyrimethanil) and IMI showed average dissipation efficiencies below 50%, so they pose a potential to accumulate in this kind of soils.

Associations of food addiction with metabolic control, medical complications and depression among patients with type 2 diabetes

AIMS

Food addiction (FA) is conceptualized as a behavioral pattern that is similar in some ways to addictions to alcohol and other substances. This disorder has not been well studied among patients with type 2 diabetes (T2DM). We aimed to analyze if there is any relationship between FA and clinical or psychological variables among patients with T2DM.

METHODS

Three hundred patients with T2DM were analyzed cross-sectionally. Participants were evaluated for the presence of FA by completing the Yale Food Addiction Scale 2.0 questionnaire.

RESULTS

29.3% of patients screened positive for FA. Patients with FA had a greater BMI (33.41 ± 7.5 vs. 31.6 ± 5.9 kg/m²; p = 0.04). HbA1c was higher among individuals with FA (7.9 ± 4.4 vs. 7.6 ± 1.4%, p = 0.008). The proportion of subjects with diabetic retinopathy, neuropathy and nephropathy was greater among patients with criteria for FA compared with patients without this condition (25% vs. 13.2%, 29.5% vs. 21.8% and 32% vs. 22.3%; p = 0.03, p = 0.05 and p = 0.05, respectively). The percentage of patients with FA with significant depressive symptoms was also greater (36.4% vs. 18.5%; p = 0.002).

CONCLUSIONS

The presence of FA among T2DM patients implied a worse glycaemic control. Microvascular complications and depressive symptoms were higher among these patients.

Portable dehumidifiers condensed water: A novel matrix for the screening of semi-volatile compounds in indoor air

The comprehensive identification of organic species existing in indoor environments is a key issue to understand their impact in human health. This study proposes the analysis of condensed water samples, collected with portable dehumidifiers, to characterize semi-volatile compounds in the gas phase of confined areas. Water samples are concentrated by solid-phase extraction (SPE). The obtained extracts are analysed by gas chromatography (GC) time-of-flight mass spectrometry (TOF-MS), following a non-target screening data mining approach. In first term, spectra of deconvoluted compounds are compared with those in NIST low resolution library; thereafter, tentative identifications are verified using an in-house database of accurate electron ionization (EI) MS spectra. Chromatographic (retention index) and spectral data are combined for unambiguous species identification. The potential of condensed water samples to reflect changes in the composition of indoor atmospheres, the match between data obtained using different dehumidifiers, and the relative concentration efficiency of condensed water compared to that attained by active sampling of moderate air volumes are discussed. A total of 141 semi-volatile compounds were identified (98 confirmed against authentic standards) in a set of 21 samples obtained from different homes and working places. This list contains more than 40 fragrances (including several potential allergens), solvents and intermediates in the production of polymeric materials, plasticizers and flame retardants.

First-trimester fasting glycemia as a predictor of gestational diabetes (GDM) and adverse pregnancy outcomes

AIMS

Studies to prevent gestational diabetes (GDM) have shown the best results when lifestyle measures have been applied early in pregnancy. We aimed to investigate whether first-trimester fasting plasma glucose (FPG) could predict GDM risk and adverse pregnancy outcomes.

METHODS

A retrospective analysis of prospectively collected data from singleton pregnancies who were attended at our hospital between 2008 and 2018 (n = 27,198) was performed. We included patients with a recorded first-trimester FPG and complete pregnancy data (n = 6845). Patients under 18, with pregestational diabetes or reproductive techniques, were excluded. First-trimester FPG was evaluated as a continuous variable and divided into quartiles. GDM was diagnosed by NDDG criteria. The relationship between first- and second-trimester glucose > 92 mg/dL was also investigated. The relationship between FPG and pregnancy outcomes was assessed in 6150 patients who did not have GDM.

RESULTS

Maternal age was 34.2 ± 3.9 years, BMI 23.1 ± 3.7 kg/m² and mean FPG 83.0 ± 7.3 mg/dL. Glucose quartiles were: ≤ 78, 79-83, 84-87 and ≥ 88 mg/dL. First-trimester FPG predicted the risk of GDM (7%, 8%, 10.2% and 16% in each quartile, p < 0.001) and the risk of second-trimester glucose > 92 mg/dL (2.6%, 3.8%, 6.3% and 11.4% in each quartile, p < 0.001). FPG was significantly associated with LGA (8.2%, 9.3%, 10% and 11.7% in each quartile, p = 0.011) but not with other obstetrical outcomes. In a multivariate analysis including age, BMI, tobacco use, number of pregnancies and weight gained during pregnancy, first-trimester FPG was an independent predictor of LGA.

CONCLUSIONS

First-trimester FPG is an early marker of GDM and LGA.

The Effect of Different Oxygen Surface Functionalization of Carbon Nanotubes on the Electrical Resistivity and Strain Sensing Function of Cement Pastes

Different studies in the literature indicate the effectiveness of CNTs as reinforcing materials in cement-matrix composites due to their high mechanical strength. Nevertheless, their incorporation into cement presents some difficulties due to their tendency to agglomerate, yielding a non-homogeneous dispersion in the paste mix that results in a poor cement-CNTs interaction. This makes the surface modification of the CNTs by introducing functional groups on the surface necessary. In this study, three different treatments for incorporating polar oxygen functional groups onto the surface of carbon nanotubes have been carried out, with the objective of evaluating the influence of the type and oxidation degree on the mechanical and electrical properties and in strain-sensing function of cement pastes containing CNTs. One treatment is in liquid phase (surface oxidation with HNO₃/H₂SO₄), the second is in gas phase (O₃ treatment at 25 and 160 °C), and a third is a combination of gas-phase O₃ treatment plus NaOH liquid phase. The electrical conductivity of cement pastes increased with O₃- and O₃-NaOH-treated CNTs with respect to non-treated ones. Furthermore, the oxygen functionalization treatments clearly improve the strain sensing performance of the CNT-cement pastes, particularly in terms of the accuracy of the linear correlation between the resistance and the stress, as well as the increase in the gage factor from 28 to 65. Additionally, the incorporation of either non-functionalized or functionalized CNTs did not produce any significant modification of the mechanical properties of CNTs. Therefore, the functionalization of CNTs favours the de-agglomeration of CNTs in the cement matrix and consequently, the electrical conductivity, without affecting the mechanical behaviour.

Introspective and Neurophysiological Measures of Mind Wandering in Schizophrenia

Patients with schizophrenia have often been considered to be “in their own world”. However, this casual observation has not been proven by scientific evidence so far. This can be explained because scientific research has usually addressed cognition related to the processing of external stimuli, but only recently have efforts been made to explain thoughts, images and feelings not directly related to the external environment. This internally directed cognition has been called mind wandering. In this paper, we have explored mind wandering in schizophrenia under the hypothesis that a predominance of mind wandering would be a core dysfunction in this disorder. To this end, we collected verbal reports and measured electrophysiological signals from patients with schizophrenia spectrum disorders and matched healthy controls while they were presented with segments of films. The results showed that mind wandering was more frequent in patients than in controls. This higher frequency of mind wandering did not correlate with deficits in attentional, memory or executive functioning. In addition, mind wandering in patients was characterized by a different pattern of Electroencephalography (EEG) complexity in patients than in controls, leading to the suggestion that mind wandering in schizophrenia could be of a different nature. These findings could have relevant implications for the conceptualization of this severe mental disorder.

Assessment of gas chromatography time-of-flight mass spectrometry for the screening of semi-volatile compounds in indoor dust

Indoor dust contains a complex mixture of anthropogenic and synthetic compounds closely related to dermal and respiratory diseases. Target methods have been developed for the quantification of distinct groups of substances in dust samples; however, the comprehensive characterization of the different species existing in this matrix remains a challenging issue. Herein, we assess the performance of gas chromatography (GC) time-of-flight mass spectrometry (TOF-MS), using electron ionization (EI), for the screening of compounds present in indoor dust. Samples are processed by pressurized-liquid extraction (PLE) before GC-EI-TOF-MS analysis. The study proposes a data mining workflow for the non-target identification of species contained in dust extracts, aided by preliminary comparison with nominal resolution EI-MS spectra in the NIST17 library. The possibilities, and the limitations, of the above approach are discussed and the identities of >75 compounds are confirmed by comparison with authentic standards in dust from indoor environments. Some species, such as indigo, phthalic anhydride, 2,4-toluene di-isocyanate, phthalimide, certain UV absorbers and octyl isothiazolinone, identified in this research, have not been previously considered in target methods dealing with dust analysis. The study also evaluates two different algorithms for the suspected-target screening of dust extracts using a customized library of accurate EI-MS spectra. Finally, a semi-quantitative estimation of the range of concentrations for a group of 44 pollutants in a set of 27 dust samples is provided.

Estudio morfométrico de pezuñas en genotipos bovinos criados en los humedales del Ñeembucú Paraguay

Se evaluó la morfometría de pezuñas en bovinos criados en los humedales del Ñeembucú y áreas de influencia. Participaron 80 hembras adultas agrupadas por genotipos en Criollo Ñeembucú; Criollo Pilcomayo; Nelore; Brahman y Brangus, analizándose Longitud muralla (LM); Altura pezuña (AP); Longitud talón (LT); Longitud pezuña (LP); Diagonal pezuña (DP); Grosor pezuña (GP). El análisis con el software R incluyó varianza paramétrica y no paramétrica, y en las pezuñas anterior medial y posterior lateral, Análisis de Componentes Principales, Discriminante Canónico y Clúster por el método de Ward. El Criollo Ñeembucú mostró mayores LM y AP, el Nelore las menores; la LT, reveló estabilidad longitudinal en nativos, no así en el Nelore. La LP fue mayor en Criollos, Nelore y Brangus. La DP mostró adecuado reparto de las cargas. El GP, mayor en el Nelore y Brangus, fue menor en el Brahman, con talones bajos y menores DP y LP. El ACP explicó más del 70% de la variación. El CP1 se asoció positivamente a DP, LP, LM, LT y AP; el CP2 fue vinculado a GP. El ADC explicó mejor la variabilidad entre genotipos, con valores elevados de GP en el Nelore y bajos en el Brahman. El método de Ward conformó grupos con la mayoría de los genotipos, revelando poca diferencia entre individuos; no obstante, algunos clústeres concentraron en grupos diferentes a la mayoría de los animales Nelore y Brahman.

TLI in pediatric patients

PURPOSE

Hematopoietic progenitor cell transplantation (HSCT) is a procedure used in different hematological diseases as part of the curative treatment, so the investigators propose a system of conditioning of reduced intensity based on total lymphoid irradiation (TLI) as an alternative to the classic total body irradiation (TBI) followed by haploidentical transplantation in patients compatible with a single HLA haplotype, as an alternative to patients who do not have an HLA compatible donor.

MATERIALS AND METHODS

A cohort of 25 patients with hematological disease underwent haploidentical HSCT from February 2015 to May 2018, conditioned with TLI from day - 10 (2-4 days of treatment) followed by thiotepa (5 mg/kg/12 h) and melphalan (70 mg/m²/day) prior to HSCT and prophylaxis with ciclosporin (1.5 mg/kg/12 h). 2 Gy/fraction was administered to complete 8 Gy with IMRT and VMAT technique.

RESULTS

12% rejection of the transplant was obtained with acute GVHD < II (48%) and chronic GVHD 12%. No acute toxicity was recorded in irradiated patients and 56% survival of patients at the end of follow-up.

CONCLUSION

Conditioning the haploidentical transplant with TLI, IMRT, and VMAT techniques compared with TBI and RT3D-C techniques is a feasible technique that helps inducing the necessary immunosuppression in patients with a high risk of graft rejection, minimal adverse effects, low incidence of GVHD, and high survival rate.

Clinically significant intra-day variability of serum progesterone levels during the final day of oocyte maturation: a prospective study with repeated measurements

STUDY QUESTION

Is there significant variability in progesterone levels during the final day of oocyte maturation in women undergoing ovarian stimulation?

SUMMARY ANSWER

Progesterone levels drop from the basal level up to 44% during the final day of oocyte maturation in women undergoing ovarian stimulation.

WHAT IS KNOWN ALREADY

It has been suggested that elevated progesterone levels on the final day of ovarian stimulation may be related to poorer outcomes in in vitro fertilization fresh cycles due to a negative impact on the endometrium. However, despite conflicting results regarding the actual effect of progesterone on pregnancy rates and the lack of a well-established cut off, currently many IVF patients have their embryo transfer deferred when progesterone values surpass a threshold of 1.5 ng/ml on the day of ovulation triggering.

STUDY DESIGN, SIZE, DURATION

This was a prospective cohort study conducted in 22 oocyte donors of a university-affiliated fertility centre between November 2017 and January 2018. We calculated the sample size to detect a difference of 15% between the first and last progesterone measurements with a 5% false-positive rate in a two-sided test with 80% statistical power and a 95% confidence interval (CI).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Progesterone circulating levels were evaluated at four different times during the final day of oocyte maturation (08:00, 12:00, 16:00 and 20:00) before ovulation triggering in healthy oocyte donors. A flexible antagonist protocol was used, and ovarian stimulation was achieved with recombinant follicle-stimulating hormone (FSH) in all cases. The pairwise percentage differences in progesterone levels for each patient were calculated. Univariate linear regression analysis was adopted in order to evaluate variables associated with progesterone levels on the first measurement. The intra-day variability of progesterone was analysed using mixed models.

MAIN RESULTS AND THE ROLE OF CHANCE

Mean serum progesterone values at 08:00, 12:00, 16:00 and 20:00 were 1.75 ng/ml, 1.40 ng/ml, 1.06 ng/ml and 0.97 ng/ml. The progesterone difference between 08:00 and 20:00 was 0.77 (95% CI, 0.56–0.99), which is equivalent to a 44% decline in the mean progesterone values between the first (08:00) and the last determination (20:00; P < 0.001). Among those patients with basal (08:00) progesterone levels >1.5 ng/ml (n = 10), 70% (n = 7) showed levels reduced to <1.5 ng/ml on the last determination of the day (20:00). A mixed model analysis revealed that the progesterone reduction during the day was significantly associated with time and total recombinant FSH dose administered.

LIMITATIONS, REASONS FOR CAUTION

Only young healthy oocyte donors stimulated with an antagonist protocol using recombinant FSH were included. Extrapolation to the general IVF population, with different stimulation protocols and gonadotropins, needs to be confirmed.

WIDER IMPLICATIONS OF THE FINDINGS

This study suggests that a single progesterone determination on the final day of oocyte maturation is not reliable enough to make clinical decisions due to the enormous variation in progesterone during the day. Further studies are needed to better define the impact of the follicular progesterone rise on the endometrium of IVF cycles.

STUDY FUNDING/COMPETING INTEREST(S)

Funding was granted from Fundació Santiago Dexeus Font. N.P.P. received unrestricted grants and/or lectures fees from Roche Diagnostics, MSD, Merck, Ferring Pharmaceuticals, IBSA, Theramex and BESINS International, not associated with the current study. The remaining authors have no competing interests.

TRIAL REGISTRATION NUMBER

Clinicaltrials.gov NCT03366025.

Direct analysis in real time accurate mass spectrometry determination of bisphenol A in thermal printing paper

Contact with thermal printing paper is a relevant source of dermal exposure to unbonded bisphenol A (BPA). In order to limit this exposure route, the European Union has introduced a drastic reduction in the maximum allowed concentration of BPA in thermal paper produced after beginning of year 2020. This study investigates the suitability of direct analysis in real time (DART), combined with accurate mass spectrometry, as a faster alternative to chromatography-based methods for the quantitative determination of BPA, and three analogues species, in receipts and tickets usually printed on thermal paper. The ionization efficiency of these compounds is evaluated under different conditions, and the effect of instrumental parameters of the DART source in the observed responses is discussed. The yield of the DART desorption-ionization process was greatly improved when compounds are previously converted into their acetyl derivatives; thereafter, the temperature of electronically excited helium atoms was the most relevant of the evaluated instrumental parameters. Under optimized conditions, the reported method provided recoveries in the range from 90 to 110%, a limit of quantification of 0.004% (w:w), well below the maximum concentration established after 2020 for BPA (0.02%, w:w), and permitted to perform duplicate determinations of each sample extract with a response time around 1 min. The accuracy of BPA levels found in non-spiked samples was confirmed using GC-EI-MS as reference technique. BPA was systematically noticed in the processed samples with concentrations ranging from 0.005% to more than 6%.

Selective determination of sartan drugs in environmental water samples by mixed-mode solid-phase extraction and liquid chromatography tandem mass spectrometry

Herein, a method for the simultaneous determination of the currently prescribed sartan drugs (eprosartan, EPR; olmesartan, OLM; losartan, LOS; candesartan, CAN; telmisartan, TEL; irbesartan, IRB; and valsartan, VAL), and the biodegradation product valsartan acid (VALA), in water samples (raw and treated wastewater, river and tap water) was developed. Solid-phase extraction (SPE) and ultra-performance liquid chromatography (UPLC) tandem mass spectrometry (MS/MS) were employed as concentration and determination techniques, respectively. Different sorbents and elution solvents were tested for sample preparation. Under optimized conditions, samples at neutral pH (6-8 units) were concentrated using mixed-mode (reversed-phase and anionic exchange) cartridges. Thereafter, the sorbent was washed with 5 mL of a methanol: water (1:1) solution, dried under a nitrogen stream and compounds were eluted with 2 mL of methanol: NH₃ (98:2). The accuracy of the method (accounting for SPE efficiency and matrix effects during electrospray ionization) was investigated using solvent-based calibration standards. Global recoveries, obtained for different water matrices (tap, river, treated and raw wastewater), ranged from 82% to 134%, with standard deviations between 2 and 18%. LOQs varied from 2 to 50 ng L^-1. Analysis of un-spiked samples confirmed: (1) the incomplete removal of sartans at sewage treatment plants (STPs), (2) the formation of VALA during municipal water treatment, and (3) the presence of VALA in the processed tap water samples. Additional findings of the current study are the detection of hydroxylated derivatives of the sartan drugs IRB and LOS in wastewater, and the E-Z isomerization of EPR in environmental water samples.

New insights into the coordination between the polymerization and 3'-5' exonuclease activities in ϕ29 DNA polymerase

Bacteriophage ϕ29 DNA polymerase has two activities: DNA polymerization and 3′-5′ exonucleolysis governed by catalytic sites present in two structurally distant domains. These domains must work together to allow the correct replication of the template and to prevent the accumulation of errors in the newly synthesized DNA strand. ϕ29 DNA polymerase is endowed with a high processivity and strand displacement capacity together with a high fidelity. Previous studies of its crystallographic structure suggested possible interactions of residues of the exonuclease domain like the Gln180 with the fingers subdomain, or water mediated and direct hydrogen bond by the polar groups of residues Tyr101 and Thr189 that could stabilize DNA binding. To analyse their functional importance for the exonuclease activity of ϕ29 DNA polymerase we engineered mutations to encode amino acid substitutions. Our results confirm that both residues, Tyr101 and Thr189 are involved in the 3′-5′ exonuclease activity and in binding the dsDNA. In addition, Tyr101 is playing a role in processivity and Thr189 is an important determinant in the fidelity of the DNA polymerase. On the other hand, the biochemical characterization of the mutant derivatives of residue Gln180 showed how the mutations introduced enhanced the 3′-5′ exonuclease activity of the enzyme. A potential structural conformation prone to degrade the substrate is discussed.