FAIR data sharing: The roles of common data elements and harmonization.

The value of robust and responsible data sharing in clinical research and healthcare is recognized by patients, patient advocacy groups, researchers, journal editors, and the healthcare industry globally. Privacy and security concerns acknowledged, the act of exchanging data (interoperability) along with its meaning (semantic interoperability) across studies and between partners has been difficult, if not elusive. For shared data to retain its value, a recommendation has been made to follow the Findable, Accessible, Interoperable, Reusable (FAIR) principles. Without applying appropriate data exchange standards with domain-relevant content standards and accessible rich metadata that uses applicable terminologies, interoperability is burdened by the need for transformation and/or mapping. These obstacles to interoperability limit the findability, accessibility and reusability of data, thus diminishing its value and making it impossible to adhere to FAIR principles. One effort to standardize data collection has been through common data elements (CDEs). CDEs are data collection units comprising one or more questions together with a set of valid values. Some CDEs contain standardized terminology concepts that define the meaning of the data, and others include links to unique terminology concept identifiers and unique identifiers for each CDE; however, usually CDEs are defined for specific projects or collaborations and lack traceable or machine readable semantics. While the name implies that these are 'common', this has not necessarily been a requirement, and many CDEs have not been commonly used. The National Institutes of Health (NIH) CDEs are, in fact, a conglomerate of CDEs developed in silos by various NIH institutes. Therefore, CDEs have not brought the anticipated benefit to the industry through widescale interoperability, nor is there widespread reuse of CDEs. Certain institutes in the NIH recommend, albeit do not enforce, institute-specific preferred CDEs; however, at the NIH level a preponderance of choice and a lack of any overarching harmonization of CDEs or consistency in linking them to controlled terminology or common identifiers create confusion for researchers in their efforts to identify the best CDEs for their protocol. The problem of comparing data among studies is exacerbated when researchers select different CDEs for the same variable or data collection field. This manuscript explores reasons for the disappointingly low adoption of CDEs and the inability of CDEs or other clinical research standards to broadly solve the interoperability and data sharing problems. Recommendations are offered for rectifying this situation to enable responsible data sharing that will help in adherence to FAIR principles and the realization of Learning Health Systems for the sake of all of us as patients.

Michael addition of carbonyl compounds to nitroolefins under the catalysis of new pyrrolidine-based bifunctional organocatalysts.

Novel bifunctional pyrrolidine-based organocatalysts for the asymmetric Michael addition of carbonyl compounds to nitroolefins have been synthesised from homoallylamines, which are easily obtained from (R)-glyceraldehyde as a chiral precursor. Under optimal reaction conditions, these bifunctional organocatalysts showed a high catalytic efficiency (almost quantitative yield in most cases) and stereoselectivity in the Michael addition reactions of a variety of aldehydes (up to 98 : 2 dr and 97% ee) and ketones (up to 98 : 2 dr and 99% ee) to nitroolefins.

Lack of adherence to SHEA-IDSA treatment guidelines for Clostridium difficile infection is associated with increased mortality.

OBJECTIVES: The objective of this study was to determine our institution's compliance with 2010 Society for Healthcare Epidemiology of America and IDSA Clostridium difficile infection (CDI) treatment guidelines and their respective outcomes. METHODS: We collected clinical parameters, laboratory values, antibiotic therapy and clinical outcomes from the electronic medical records for all patients hospitalized at our institution with a diagnosis of CDI from December 2012 to November 2013. We specifically evaluated whether SHEA-IDSA treatment guidelines were followed and evaluated the associations between guideline adherence and severe outcomes including mortality. RESULTS: We identified 230 patients with CDI meeting inclusion criteria during the study period. Of these, 124 (54%) were appropriately treated, 46 (20%) were under-treated and 60 (26%) were over-treated. All-cause 90 day mortality was 17.4% overall; 43.5% in the under-treated group versus 12.9% in those appropriately treated (P < 0.0001) and 10.9% in those appropriately treated plus over-treated (P < 0.0001). Similarly, 90 day mortality attributed to CDI was 21.7% in those under-treated versus 8.9% in those appropriately treated (P = 0.03) and 8.2% in those either appropriately treated or over-treated (P = 0.015). Severe-complicated CDI occurred in 46 patients. In this subgroup, there was a non-significant trend towards increased mortality in under-treated patients (56.7%) compared with appropriately treated patients (37.5%, P = 0.35). Under-treatment was also associated with a higher rate of CDI-related ICU transfer (17.4% versus 4.8% in those appropriately treated, P = 0.023). CONCLUSIONS: Adherence to CDI treatment guidelines is associated with improved outcomes especially in those with severe disease. Increased emphasis on provision of appropriate, guideline-based CDI treatment appears warranted.

Long-term results after treatment of pertrochanteric femoral fractures with percutaneous compression plate (PCCP).

OBJECTIVE: This study sought to evaluate the long-term osteosynthesis results for AO/OTA 31.A1-A2 pertrochanteric fractures treated with the percutaneous compression plate (PCCP). MATERIALS AND METHODS: This investigation was a retrospective observational descriptive study of 335 patients, with a minimum follow-up of 2 years and a maximum follow-up of 8 years (2004-2011). RESULTS: The average post-operative hospital stay was 6.2 days, and the average decrease in haemoglobin levels after the intervention was 2.7 mg/dL, with transfusion required for one-third of the patients. Complications related to the implant were observed in 4.2 % of patients; the most notable complication was cut-out (2.4 % of patients), and 3 cases involved pseudarthrosis with breakage of the implant (0.9 % of patients). CONCLUSIONS: From the results obtained in this study and an analysis of previously published work, we believe that the PCCP may be the implant of choice for AO/OTA 31.A1-A2 fractures.

Biallelic HERC1 mutations in a syndromic form of overgrowth and intellectual disability.

We report two Colombian siblings affected by overgrowth, intellectual disability and facial dysmorphism. Exome (via NGS) and Sanger sequencing revealed that biallelic sequence variants in a novel gene (HERC1) might be related to the disease pathogenesis. These results provide useful data for future genotype-phenotype correlations and for a molecular diagnosis of overgrowth.

Medication reconciliation at admission and discharge: an analysis of prevalence and associated risk factors.

INTRODUCTION: Medication errors are frequent at care transition points and can have serious repercussions. Study objectives were to examine the frequency/type of reconciliation errors at hospital admission and discharge and to report on the drugs involved, associated risk factors and potential to cause harm in a healthcare setting with comprehensive digital health records. MATERIAL AND METHODS: A prospective observational 2-year study was conducted in the Internal Medicine Department of a regional hospital. The best possible medication history was obtained from different sources by clinical pharmacists and compared with prescriptions at admission and discharge. The frequency and type of reconciliation errors were studied at admission and discharge, evaluating risk factors for their occurrence and their potential to cause harm. RESULTS: The study included 814 patients (mean age: 80.2 years). At least one reconciliation error was detected in 525 (64.5%) patients at admission, with a mean of 2.2 ± 1.3 errors per patient and in 235 (32.4%) patients at discharge. Drug omission was the most frequent reconciliation error (73.6% at admission and 71.4% at discharge); 39% of errors at admission and 51% at discharge had potential to cause moderate or severe harm. The risk of error at admission was higher with more pre-admission drugs (p < 0.001) and, among patients with reconciliation errors, the number of errors was significantly higher in those receiving more drugs pre-admission or with more comorbidities. The risk at discharge was higher in patients with more drugs prescribed at discharge (p = 0.04) and in those with a longer hospital stay (p = 0.03). CONCLUSIONS: Medication reconciliation procedures are required to minimise medication discrepancies and enhance patient safety. Integration of patient health records across care levels is necessary but not sufficient to prevent errors.

Evidence of an association between 10/10 genotype of DAT1 and endophenotypes of attention deficit/hyperactivity disorder.

INTRODUCTION: Genetic variance of attention deficit-hyperactivity disorder (ADHD) is a strong determinant of this disorder. The 40 base pairs (bp) variable number tandem repeat (VNTR) located in the 3' untranslated region (UTR) of DAT1 gene increases the expression of the dopamine transporter. Therefore, DAT1 has been associated with susceptibility to ADHD. OBJECTIVE: To determine the association between the VNTR of DAT1 and the phenotype of ADHD or its endophenotypes in a sample of children aged between 6 and 15 years from Bogotá. SUBJECTS AND METHODS: We selected 73 patients with ADHD and 54 controls. WISC test was applied in all subjects and executive functions were assessed. The VNTR of DAT1 was polymerase chain reaction-amplified. Data regarding population genetics and statistical analysis were obtained. Correlation and association tests between genotype and neuropsychological testing were performed. RESULTS: The DAT1 polymorphism was not associated with ADHD (P=.85). Nevertheless, the 10/10 genotype was found to be correlated with the processing speed index (P<.05). In the hyperactivity subtype, there was a genotypic correlation with some subtests of executive function (cognitive flexibility) (P≤.01). In the combined subtype, the 10/10 genotype was associated with verbal comprehension index of WISC (P<.05). CONCLUSIONS: A correlation was found between DAT1 VNTR and the subtest "processing speed index" of WISC and the subtest "cognitive flexibility" of executive functions. To our knowledge, this is the first report to assess DAT1 gene in a Colombian population.

Cloning and characterization of the Mx1, Mx2 and Mx3 promoters from gilthead seabream (Sparus aurata).

Mx proteins are main effectors of the antiviral innate immune response mediated by type I interferon (IFN I). Actually, diverse Mx proteins from fish proved highly active against fish viruses, standing out among them the Mx1, Mx2 and Mx3 from gilthead seabream (Sparus aurata), a species exhibiting a natural resistance to viral diseases. In this study, the structure and functional activity of their corresponding promoters (pMx1, pMx2 and pMx3) have been assessed. The three promoters present an identical 3' region of 157 bp, exhibiting a single canonical interferon-stimulated response element (ISRE), which is indispensible for the poli:IC induction of pMx1 and pMx3, while not for that of pMx2. In the remaining part of the three promoters other regulatory motifs were identified, as gamma IFN activated sites in variable number (1, 4 and 2 in pMx1, pMx2 and pMx3, respectively), as well as several independent GAAA elements or ISRE core sequences (13, 15 and 12 in pMx1, pMx2 and pMx3, respectively). The structural dissimilarities shown by the three promoters parallels with the differences observed in their response profiles, in terms of the time course of the induction, and basal and induced expression levels of each promoter. Altogether, these findings indicate that the expression of Mx1, Mx2 and Mx3 genes from the gilthead seabream might be specifically regulated, in accordance with the functional role of each Mx protein in the successful antiviral response shown by this species.

What is behind the non-antibiotic properties of minocycline?

Minocycline is a second-generation, semi-synthetic tetracycline that has been in use in therapy for over 30 years for its antibiotic properties against both Gram-positive and Gram-negative bacteria. It displays antibiotic activity due to its ability to bind to the 30S ribosomal subunit of bacteria and thus inhibit protein synthesis. More recently, it has been described to exert a variety of biological actions beyond its antimicrobial activity, including anti-inflammatory and anti-apoptotic activities, inhibition of proteolysis, as well as suppression of angiogenesis and tumor metastasis, which have been confirmed in different experimental models of non-infectious diseases. There are also many studies that have focused on the mechanisms involved in these non-antibiotic properties of minocycline, including anti-oxidant activity, inhibition of several enzyme activities, inhibition of apoptosis and regulation of immune cell activation and proliferation. This review summarizes the current findings in this topic, mainly focusing on the mechanisms underlying the immunomodulatory and anti-inflammatory activities of minocycline.

Percutaneous plate fixation of displaced proximal humerus fractures: Do minimally invasive techniques improve outcomes and reduce complications?

OBJECTIVE: The aim of this study was to analyze the outcomes and complications of minimally invasive plate osteosynthesis (MIPO) for displaced proximal humerus fractures and elucidate if the percutaneous technique reduces the rate of avascular necrosis (AVN) without jeopardizing fracture reduction. MATERIAL AND METHODS: 118 patients with a displaced proximal humerus fracture were treated with a polyaxial locking-plate through a standardized percutaneous approach. 73 % were women and mean age was 63 years (18-89) with an average follow-up of 51 months (12-256). There were 32 two-part fractures (27 %), 57 three-part fractures (48 %) and 24 four-part fractures (25 %). Shoulder function at the last follow-up, including ROM and ability to perform daily living activities, was objectively evaluated with an adjusted Constant Score (CS). Subjective patient satisfaction was rated with an Visual Analogic Scale from 0 to 10 and the degree of residual pain with a Verbal Rating Scale (VRS). Radiographic analysis at the most recent follow-up evaluated the presence of AVN, degree of residual medial calcar displacement, and the cervicodiaphiseal angle. RESULTS: Forty patients (34 %) had a complication, 25 of them (21 %) requiring further surgery. ROM at the last follow-up was 131° of elevation (40°-180°), 38° of external rotation (SD: 17.7) and internal rotation to L3. Average adjusted Constant Score was 68 (SD: 17.76). Twenty-one patients (18 %) complained of shoulder pain (14 moderate and 7 severe) and seven were not satisfied. Radiographically, 29 patients (25 %) had varus malunion and 17 patients (14 %) showed some degree of AVN. Patients with varus malunion (CS 64.3 versus 69.8, p = 0.16) and AVN (CS 56.9 versus 70.4, p = 0.005) had lower CS. The presence of a varus malunion was directly related to the degree of initial medial calcar displacement (p = 0.001) and deficient calcar reduction at surgery (p = 0.004). AVN was statistically more prevalent when the medial calcar was inadequately reduced (p = 0.01). CONCLUSIONS: MIPO surgery for proximal humerus fractures through an anterolateral approach does not reduce the rate of mechanical complications or AVN compared with standard ORIF techniques. Moreover, percutaneous plating may preclude adequate medial calcar reduction, leading to humeral head malunion and a worse clinical outcome.

Unveiling the tartrazine binding mode with ds-DNA by UV-visible spectroscopy, electrochemical, and QM/MM methods.

Here, we studied the interaction between the food colorant tartrazine (TZ) and double stranded DNA (dsDNA), using spectroscopic, electrochemical, and computational methods such as QM/MM combined with TD-DFT. Despite the UV-vis spectroscopy is widely used to study the interaction between molecules, for the case of TZ there are discrepancies in the analyses presented in the literature available, presenting both hyperchromic and hypochromic effects and consequently different rationalizations for their results. Herein we propose the combination of UV-vis experiments with the design of high-level computational models capable of reproducing the experimental behavior to finally define the proper binding mode at the molecular scale together with the rationalization of the experimental optical response due to the complex formation. To complement the UV-vis experiments, we propose the use of electrochemical measurements, to support the results obtained through UV-vis spectroscopy, as it has been successfully used for the determination of interaction modes between small molecules and biomolecules in any condition. Our UV-vis spectroscopy experiments showed only a hypochromic effect of the absorption spectra of TZ after interaction with DNA, indicative of TZ being deeply buried in the DNA structure. The effect of ionic strength in the experimental procedures led to the dissociation of TZ, thus indicating that the interaction mode was groove binding. On the other hand, the electrochemical studies showed an irreversible reduction peak of TZ, which after the interaction with DNA exhibited a positive shift in potential that can be attributed to groove binding. The binding constant for TZ-DNA was calculated as 4.45x104M-1 (UV-vis) and 5.75x104M-1 (electrochemistry), in line with other groove binder azo dyes. Finally, through the QM/MM calculations we found that the minor-groove binding mode interacting in zones rich in adenine and thymine was the model best suited to reproduce the experimental UV-vis response.

Cancer diagnosis in Catalonia (Spain) after two years of COVID-19 pandemic: an incomplete recovery.

BACKGROUND: This study aimed to estimate potential undetected cancers over the first 2 years of the COVID-19 pandemic in Catalonia. METHODS: Cancer incidence was compared between pre-pandemic (2019) and pandemic (March 2020-January 2022) periods in the Catalan Pathology Registry (CPR) according to sex, age, and tumor site. The correlation between cancer diagnosis and COVID-19 health care workload was also evaluated by means of the Pearson's correlation coefficient (R). The expected incident cancers (E) during the pandemic were estimated by applying 2019 CPR cancer incidence specific rates by sex and 5-year age groups to the 2020 and 2021 Catalan population pyramids. CPR incident cancers were considered observed (O). Standardized incidence ratios (SIR) and 95% confidence intervals (CIs) were calculated using the O/E ratio. RESULTS: After two pandemic years, cancer diagnosis decreased by 12% (SIR 0.88, 95% CI 0.87-0.89), or ∼7700 undetected cancers (13 000 with nonmelanoma skin cancer). Without nonmelanoma skin cancer, 72% of the cancer underdiagnosis was generated in 2020. Diagnoses decreased more in men (whole pandemic -14%; 2020 -21%; 2021 -8%) than in women (-9%, -19%, -3%, respectively), dropping significantly overall in all pandemic waves but the fifth (first -37%, second -16%, third -8%, fourth -6%, fifth -2%, sixth -6%), and across all adult age groups. In the first wave, CPR cancer diagnosis was inversely correlated with COVID-19 caseload in primary care (R -0.91, 95% CI -0.97 to -0.75) and occupancy in conventional hospital wards (R -0.91, 95% CI -0.99 to -0.48) and intensive care (R -0.91, 95% CI 95% -0.98 to -0.70). CONCLUSIONS: Our study evaluated the overall pandemic impact on cancer diagnosis on a large scale and with minimal selection bias, showing that as of February 2022, cancer detection in Catalonia had not yet recovered to pre-pandemic levels. Pending cancer incidence data from population-based cancer registries, early CPR data could inform the development of Spanish cancer control plans.

Detection of incident breast and colorectal cancer cases from an administrative healthcare database in Catalonia, Spain.

OBJECTIVE: To validate the Catalan minimum basic data set (MBDS) of hospital discharges as an information source for detecting incident breast (BC) and colorectal cancer (CRC), against the Hospital del Mar Cancer Registry (RTHMar) in Barcelona (Spain) as the gold standard. METHODS: Using ASEDAT software (Analysis, Selection and Extraction of Tumour Data), we identified Catalan public hospital discharge abstracts in patients with a first-time diagnosis of BC and CRC in the years 2005, 2008, and 2011, aggregated by unique patient identifiers and sorted by date. Once merged with the RTHMar database and anonymized, tumour-specific algorithms were validated to extract data on incident cases, tumour stage, surgical treatment, and date of incidence. RESULTS: MBDS had a respective sensitivity and positive predictive value (PPV) of 78.0% (564/723) and 90.5% (564/623) for BC case detection; and 83.9% (387/461) and 94.9% (387/408) for CRC case detection. The staging algorithms overestimated the proportion of local-stage cases and underestimated the regional-stage cases in both cancers. When loco-regional stage and surgery were combined, sensitivity and PPV reached 98.3% and 99.8%, respectively, for BC and 96.4% and 98.4% for CRC. The differences between dates of incidence between RTHMar and MBDS were greater for BC cases without initial surgery, whereas they were generally smaller and homogeneous for CRC cases. CONCLUSIONS: The MBDS is a valid and efficient instrument to improve the completeness of a hospital-based cancer registry (HBCR), particularly in BC and CRC, which require hospitalization and are predominantly surgical.

Risk-factors for emerging bloodstream infections caused by extended-spectrum beta-lactamase-producing Escherichia coli.

Risk-factors for bloodstream infections caused by extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli were investigated using an exploratory case-double control study in which 43 cases (70% producing CTX-M enzymes) were compared with: (i) 86 patients with bacteraemia caused by non-ESBL-producing E. coli; and (ii) 86 hospitalised patients. Previous follow-up as an outpatient, urinary catheterisation and use of oxyimino-beta-lactams or fluoroquinolones were independent risk-factors for ESBL-producing E. coli among patients with E. coli bacteraemia, and previous use of oxyimino-beta-lactams or fluoroquinolones were also independent risk-factors among hospitalised patients. These findings may help in identifying patients at greater risk for bloodstream infection caused by ESBL-producing E. coli in endemic areas.

Immunomodulatory tetracyclines ameliorate DNBS-colitis: Impact on microRNA expression and microbiota composition.

OBJECTIVE: The use of immunomodulatory antibiotics to simultaneously target different factors involved in intestinal inflammatory conditions is an interesting but understudied pharmacological strategy. A great therapeutic potential has been obtained with minocycline and doxycycline in experimental colitis. Therefore, understanding the contribution of the different activities of immunomodulatory tetracyclines is crucial for the improvement and translation of their use into clinic. DESIGN: A comparative pharmacological study including tetracyclines and other antibiotic or immunomodulatory drugs was performed in 2,4-dinitrobenzene sulfonic acid (DNBS)-induced colitis in mice. The correlation between the therapeutic efficacy of each drug and changes in the gut microbiota composition, markers of barrier integrity, inflammatory mediators, microRNAs and TLRs was analysed to identify the main mechanisms of action. RESULTS: Tetracyclines counteracted most of the markers found altered in DNBS-colitis, which differed from effects of corticosteroid treatment. Of note, administration of tetracyclines led to increased mucosal protection, associated with up-regulated expression of CCL2, miR-142 and miR-375. All drugs with antibiotic activity ameliorated the progression of inflammation and reduced neutrophil-related genes, such as miR-223, despite their effects were not associated with restored intestinal dysbiosis. However, reduced bacterial richness was correlated with increased expression of TLR2 and TLR9 in antibiotic-treated groups and TLR6 was also up-regulated by the immunomodulatory tetracyclines with higher efficacy (doxycycline, minocycline and tigecycline). CONCLUSION: The anti-inflammatory effect of tetracyclines involves specific modifications in TLR and microRNA expression leading to an improved microbial-derived signalling and mucosal protection. These results support the potential of immunomodulatory tetracyclines to prevent inflammation-associated tissue damage in acute intestinal inflammation.

Endoscopic Treatment for Vesicoureteral Reflux in Recurrent Urinary Tract Infections in Kidney Transplant: Experience of One Center.

Vesicoureteral reflux (VUR) after renal transplantation in adult patients has been reported. In renal transplant recipients, symptomatic urinary tract infection can cause high morbidity despite improved immunosuppressive and antibiotic treatment. In our country there have been few reported cases about use of copolymer of dextranomer and hyaluronic acid (DX-HA) injection in a renal transplant. We present 3 cases of recurrent or complicated infections with evidence of high-grade VUR, which were treated with DX-HA. Only 1 case had a partial remission; however, there were no episodes of urinary tract infection in 12 months of follow-up. Suburethral injection is an endoscopic treatment modality with low morbidity in our country.

Immunomodulatory tetracyclines shape the intestinal inflammatory response inducing mucosal healing and resolution.

BACKGROUND AND PURPOSE: Immunomodulatory tetracyclines are well-characterized drugs with a pharmacological potential beyond their antibiotic properties. Specifically, minocycline and doxycycline have shown beneficial effects in experimental colitis, although pro-inflammatory actions have also been described in macrophages. Therefore, we aimed to characterize the mechanism behind their effect in acute intestinal inflammation. EXPERIMENTAL APPROACH: A comparative pharmacological study was initially used to elucidate the most relevant actions of immunomodulatory tetracyclines: doxycycline, minocycline and tigecycline; other antibiotic or immunomodulatory drugs were assessed in bone marrow-derived macrophages and in dextran sodium sulfate (DSS)-induced mouse colitis, where different barrier markers, inflammatory mediators, microRNAs, TLRs, and the gut microbiota composition were evaluated. The sequential immune events that mediate the intestinal anti-inflammatory effect of minocycline in DSS-colitis were then characterized. KEY RESULTS: Novel immunomodulatory activity of tetracyclines was identifed; they potentiated the innate immune response and enhanced resolution of inflammation. This is also the first report describing the intestinal anti-inflammatory effect of tigecycline. A minor therapeutic benefit seems to derive from their antibiotic properties. Conversely, immunomodulatory tetracyclines potentiated macrophage cytokine release in vitro, and while improving mucosal recovery in colitic mice, they up-regulated Ccl2, miR-142, miR-375 and Tlr4. In particular, minocycline initially enhanced IL-1ß, IL-6, IL-22, GM-CSF and IL-4 colonic production and monocyte recruitment to the intestine, subsequently increasing Ly6C- MHCII+ macrophages, Tregs and type 2 intestinal immune responses. CONCLUSIONS AND IMPLICATIONS: Immunomodulatory tetracyclines potentiate protective immune pathways leading to mucosal healing and resolution, representing a promising drug reposition strategy for the treatment of intestinal inflammation.

A simple methodology for the evaluation of groundwater pollution risks.

Groundwater represents a very significant source of fresh water for irrigation and drinking purposes and therefore preserving the availability and quality of this resource is extremely important. A first assessment of the amount of pollutants that can be exported to groundwater via soil drainage can be made by a) measuring the amount of contaminants present in the soil solution at the bottom of the soil after a prolonged simulated rainfall event, and b) estimating the amount of drainage water passing the soil bottom during a period of time long enough to include sufficient instances of both, wet and dry episodes inherent to the local climate. Drainage water was estimated by means of a simple infiltration model ("bucket model") which computes on a daily basis the inputs and outputs of soil water through rainfall and evapotranspiration generated by a stochastic model of the local climate along a period of 50-100 years. The methodology was applied in the Guadiamar valley after the toxic spill of a pyrite mine in Aznalcóllar (Spain). The results show that Zn is the dominant contaminant at the site with a 1.2 g m(-2)year(-1) contribution to groundwater. The presence of a gravel rich horizon below 50 cm depth reveals an increase in drainage and the threat to groundwater.

Guidelines for improving organic carbon recovery by the wet oxidation method.

The study of soil degradation processes as well as the monitoring of environmental quality often yields large sample batches in which organic carbon is the key property to be determined. A description is given for a rapid method to analyse organic carbon by wet oxidation; the reaction is carried out with 3ml K(2)Cr(2)O(7) and 6ml H(2)SO(4) in small vials, and Cr(3+) resulting from organic C oxidation is determined by spectrophotometry. No special equipment is needed and handling is reduced to a minimum, enabling over 100 samples per day to be analysed. There is one important detail in the operation protocol: the vials are placed inside an insulator block during oxidation. Heat insulation retards the cooling of vials, which results in a high organic C recovery (over 0.90). The improved method is feasible, simple, and easy to perform. Reproducibility was lower than 10% and recoveries from certified reference materials were about 90%. The simplified method is recommended for widespread organic C content sampling.

Prediction of acute toxicity of organophosphorus pesticides using topological indices.

Topological indices were used in the prediction of the acute toxicity (intraperitoneal and oral LD(50)) of organophosphorus pesticides on rats. Models with six variables for the prediction of LD(50)-i.p. (r = 0.849, Q(2) = 0.613) and eight variables for LD(50)-oral (r = 0.906, Q(2) = 0.701) were selected. External group and cross-validation by use of leave-n-out tests were also performed in order to assess the stability and the prediction performance of the selected topological models.