SARS-CoV-2 seroprevalence in workers from a Colombian University Hospital.

BACKGROUND: Antibody (Ab) tests for SARS-CoV-2 virus allows for the estimation of incidence, level of exposure and duration of immunity acquired by a previous infection. In health workers, the hospital setting might convey a greater risk of infection. AIMS: To describe the frequency of immunoglobulin G (IgG) Abs (IgG-Abs) to the SARS-CoV-2 virus among workers at a third-level university hospital in Colombia. METHODS: In this cross-sectional study, we included medical and non-medical personnel with at least one real-time polymerase chain reaction (RT-PCR)/antigen test between March 2020 and March 2021. In April 2021, an IgG-Ab test against SARS-CoV-2 was conducted for all participants and replicated 2 weeks later in a random sample (10%). The frequency of IgG-Abs is presented based on status (positive/negative) and time elapsed since RT-PCR/antigen test (<3 months, 3-6 months, >6 months). RESULTS: We included 1021 workers (80% women, median age 34 years (interquartile range 28-42), 73% medical personnel, 23% with previous positive RT-PCR/antigen). The overall seroprevalence was 35% (95% CI 31.6-37.4, 35% in medical and 33% in non-medical personnel). For those with a previous positive RT-PCR/antigen test, the seroprevalence was 90% (<3 months), 82% (3-6 months) and 48% (>6 months). In participants with a previous negative RT-PCR/antigen test, the seroprevalence was 17% (<3 months), 21% (3-6 months) and 29% (>6 months). CONCLUSIONS: High IgG-Ab positivity was found in hospital personnel, regardless of work activities. The prevalence of detectable Abs differed by previous RT-PCR/antigen status and time elapsed since the diagnostic test.

Effectiveness of rosuvastatin plus colchicine, emtricitabine/tenofovir and combinations thereof in hospitalized patients with COVID-19: a pragmatic, open-label randomized trial.

BACKGROUND: The use of rosuvastatin plus colchicine and emtricitabine/tenofovir in hospitalized patients with SARS-CoV-2 disease (COVID-19) has not been assessed. The objective of this study was to assess the effectiveness and safety of rosuvastatin plus colchicine, emtricitabine/tenofovir, and their combined use in these patients. METHODS: This was a randomized, controlled, open-label, multicentre, parallel, pragmatic study conducted in six referral hospitals in Bogotá, Colombia. The study enrolled hospitalized patients over 18 years of age with a confirmed diagnosis of COVID-19 complicated with pneumonia, not on chronic treatment with the study medications, and with no contraindications for their use. Patients were assigned 1:1:1:1. 1) emtricitabine with tenofovir disoproxil fumarate (FTC/TDF, 200/300 mg given orally for 10 days); 2) colchicine plus rosuvastatin (COLCH+ROSU, 0.5 mg and 40 mg given orally for 14 days); 3) emtricitabine with tenofovir disoproxil plus colchicine and rosuvastatin at the same doses and for the same period of time (FTC/TDF+COLCH+ROSU); or 4) the Colombian consensus standard of care, including a corticosteroid (SOC). The primary endpoint was 28-day all-cause mortality. A modified intention-to-treat analysis was used together with a usefulness analysis to determine which could be the best treatment. The trial was registered at ClinicalTrials.gov: NCT04359095. FINDINGS: Out of 994 candidates considered between August 2020 and March 2021, 649 (65.3%) patients agreed to participate and were enrolled in this study; among them, 633 (97.5%) were included in the analysis. The mean age was 55.4 years (SD ± 12.8 years), and 428 (68%) were men; 28-day mortality was significantly lower in the FTC/TDF+COLCH+ROSUV group than in the SOC group, 10.7% (17/159) vs. 17.4% (28/161) (hazard ratio [HR] 0.53; 95% CI 0.29 to 0.96). Mortality in the FTC/TDF group was 13.8% (22/160, HR 0.68, 95% CI 0.39 to 1.20) and 14.4% in the COLCH+ROSU group (22/153) (HR 0.78, 95% CI 0.44 to 1.36). A lower need for invasive mechanical ventilation was observed in the FTC/TDF+COLCH+ROSUV group than in the SOC group (risk difference [RD] - 0.08, 95% CI 0.11 to 0.04). Three patients presented severe adverse events, one severe diarrhoea in the COLCH+ROSU and one in the FTC/TDF+COLCH+ROSU group and one general exanthema in the FTC/TDF group. INTERPRETATION: The combined use of FTC/TDF+COLCH+ROSU reduces the risk of 28-day mortality and the need for invasive mechanical ventilation in hospitalized patients with pulmonary compromise from COVID-19. More randomized controlled trials are needed to compare the effectiveness and cost of treatment with this combination versus other drugs that have been shown to reduce mortality from SARS-CoV-2 infection and its usefulness in patients with chronic statin use.

Efficacy and safety assessment of different dosage of benznidazol for the treatment of Chagas disease in chronic phase in adults (MULTIBENZ study): study protocol for a multicenter randomized Phase II non-inferiority clinical trial.

BACKGROUND: Chagas disease (CD) continues to be a neglected infectious disease with one of the largest burdens globally. Despite the modest cure rates in adult chronic patients and its safety profile, benznidazole (BNZ) is still the drug of choice. Its current recommended dose is based on nonrandomized studies, and efficacy and safety of the optimal dose of BNZ have been scarcely analyzed in clinical trials. METHODS/DESIGN: MULTIBENZ is a phase II, randomized, noninferiority, double-blind, multicenter international clinical trial. A total of 240 patients with Trypanosoma CD in the chronic phase will be recruited in four different countries (Argentina, Brazil, Colombia, and Spain). Patients will be randomized to receive BNZ 150 mg/day for 60 days, 400 mg/day for 15 days, or 300 mg/day for 60 days (comparator arm). The primary outcome is the efficacy of three different BNZ therapeutic schemes in terms of dose and duration. Efficacy will be assessed according to the proportion of patients with sustained parasitic load suppression in peripheral blood measured by polymerase chain reaction. The secondary outcomes are related to pharmacokinetics and drug tolerability. The follow-up will be 12 months from randomization to end of study participation. Recruitment was started in April 2018. CONCLUSION: This is a clinical trial conducted for the assessment of different dose schemes of BNZ compared with the standard treatment regimen for the treatment of CD in the chronic phase. MULTIBENZ may help to clarify which is the most adequate BNZ regimen in terms of efficacy and safety, predicated on sustained parasitic load suppression in peripheral blood. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03191162. Registered on 19 June 2017.

Effect of steam explosion and enzymatic pre-treatments on pulping and bleaching of Hesperaloe funifera.

A non-wood raw material with high potential for pulp and paper applications (Hesperaloe funifera) was subjected to a steam explosion pre-treatment, and the subsequent effect of this pretreatment on biopulping and biobleaching was studied. An increase in the delignification rate, bigger than that reported for autohydrolysis and acid hydrolysis pre-treatments, and a reduction in chemical consumption were found during kraft pulping of the exploded samples. However, biopulping with the laccase-mediator system (LMS) did not lead to a reduction in the kappa number in either non-exploded or exploded unbleached pulps. On the other hand, the steam explosion pretreatment boosted the advantages of the LMS pre-treatment (decrease in kappa number and increase in brightness) favored biobleaching, with a 53.1% delignification rate and a final brightness of 67% ISO. Finally, the steam explosion pre-treatment also improved the color properties of the bleached pulp and reduced the hydrogen peroxide consumption by 24.6%.

Combination of steam explosion and laccase-mediator treatments prior to Eucalyptus globulus kraft pulping.

The effect of a pretreatment consisting of steam explosion (SE) followed by a laccase mediator system (LMS) stage on Eucalyptus globulus kraft pulping has been evaluated and compared with fungal pretreatments. Pretreatment with SE and LMS was more efficient than pretreatments using Pycnoporus sanguineus and Trametes sp. I-62. Steam explosion not only improved the enzyme penetration into the wood chips and shortened the pulping process by 60%, but also extracted around 50% of the hemicelluloses which could be converted into value-added products. The optimal conditions for the LMS treatment were 3h, 3UA/g and 40°C. Compared to SE, the SE/LMS treatment yielded an increase in delignification of 13.9% without affecting pulp properties, provided a similar screened kraft yield, and reduced consumption of chemical reagents Na(2)S and NaOH by 11.5% and 6.3%, respectively. Therefore, SE/LMS is a promising pretreatment for converting the pulp mill into a forest bio-refinery.

Biobleaching of Eucalyptus globulus kraft pulps: comparison between pulps obtained from exploded and non-exploded chips.

The aim of this work was to evaluate the response to biobleaching of steam exploded kraft pulps and to compare the results with the controls. For this end, a laccase-mediator treatment using commercial laccase (Novozyme 51003) and a natural mediator (acetosyringone) were assayed, followed by alkaline extraction and hydrogen peroxide stages. Our approach resulted in exploded biobleached pulps with lower kappa number and improved optical properties compared to controls, even after subjecting pulps to accelerated ageing. Additionally, use of hydrogen peroxide was reduced. The LMS (laccase-mediator system) had a smaller impact on the properties of the bleached pulps and on hydrogen peroxide consumption than the steam explosion process did.

Kraft pulp biobleaching using an extracellular enzymatic fluid produced by Pycnoporus sanguineus.

The aim of this work was to obtain a LMS pre-treatment applicable to industrial TCF bleaching. Kraft pulp from Eucalyptus globulus was treated at 40 degrees C/pH 3 and 60 degrees C/pH 5 for 1h using an extracellular fluid enriched in laccase produced by Pycnoporus sanguineus and acetosyringone as mediator (HBT was used as a control mediator) (L). Alkaline extraction (E) and hydrogen peroxide (P) stages were then assayed. The LEP alternative was an efficient sequence to bleach kraft pulp since the enzymatic pre-treatment boosted the subsequent chemical bleaching. The best L pre-treatment was obtained with laccase-acetosyringone at 40 degrees C/pH 3. It reduces kappa number and hexenuronic acids, increases pulp viscosity, lowers hydrogen peroxide consumption down to an 87.4% (94.0% without L) and enhances brightness up to a 59% ISO (51% ISO without L).

Bioremediation of lignosulphonates by lignin-degrading basidiomycetous fungi.

The capability of some ligninolytic fungi to degrade lignosulphonates has been studied. Three lignosulphonates concentrations, three culture media and seven different basidiomycetes in solid-cultures have been assayed to select the conditions for further experiments on submerged cultures. The best results of growth and lignosulphonate decolourization in solid-cultures were obtained with Pycnoporus sanguineus, Coriolus pubescens and Trametes sp. I-62 on Kirk's medium and 1% and 2% of lignosulphonate concentrations. In submerged cultures the lignosulphonate decolourization rate was generally higher when it was added on the 6th day, rather than when it was added from the beginning of the incubation and C. pubescens and P. sanguineus showed again the optimum results of decolourization. Extracellular laccase activity increased with lignosulphonate concentration in all assayed fungi, suggesting that lignosulphonate act as inductors of laccase activity.

Trypanocidal drugs for chronic asymptomatic Trypanosoma cruzi infection.

BACKGROUND: Prior guidelines stated that trypanocidal therapy should not be used for treating chronic asymptomatic Trypanosoma cruzi infections. However, the recent availability of clinical trials reporting high rates of parasitologic cure in children with early chronic T. cruzi infection have produced changes of these recommendations in some countries. Because of the uncertainty regarding best treatment for this stage of T. cruzi infections, the literature was reviewed systematically for a synthesis of the available evidence. OBJECTIVES: To assess the effects of trypanocidal therapy for chronic asymptomatic T. cruzi infection. SEARCH STRATEGY: We searched The Cochrane Controlled Trials Register (Issue 1, 2000), MEDLINE (start-Nov 1999), EMBASE (start - Feb 2000), LILACS (start - Feb 2000) and the Tropical Diseases Research Division of WHO database (Start - Feb 2000). Reference lists of articles were searched for relevant material. SELECTION CRITERIA: Published RCTs of trypanocidal therapy for people with chronic, asymptomatic T. cruzi infections DATA COLLECTION AND ANALYSIS: Two reviewers independently screened papers for inclusion criteria, quality assessment and data extraction. Forms were used to collect data. Reviewers resolved differences by discussion then a third reviewer if necessary. MAIN RESULTS: Of 43 papers assessed for inclusion, five RCTs (total population=756) met the inclusion criteria. The quality of the trials was rated as low (n=3) or intermediate (n=2). Two RCTs tested benznidazole in school children and three tested different agents in adults. The Odds Ratios and their 95%CI (Fixed models) were: Incidence of ECG abnormalities: 0.41 (0.09, 1.85); Negative seroconversion (AT ELISA): 10.91 (6.07, 19.58); Negative xenodiagnosis during the follow up: 5.37 (3.34, 8.64); Standardised mean reduction of antibody titres: 0.54 (0.31, 0.84). Nitroimidazolic derivatives substantially and significantly modified parasite-related outcomes compared to placebo. Other agents showed borderline or not significant effect. REVIEWER'S CONCLUSIONS: Despite major public health importance, trypanocidal.therapy for chronic asymptomatic T. cruzi infection has been tested in few, small size RCTs which were designed to assess parasitic-related, but not clinical outcomes. Therefore, the potential of trypanocidal therapy to prevent Chagas' disease among asymptomatic, chronically infected subjects is promising, but remains to be evaluated. trypanocidal therapy, particularly nitroimidazolic derivatives given to children or adults with positive xenodiagnosis improve parasite-related outcomes. The large contrast between the burden of Chagas disease and the existing evidence on its prevention points the need to test these or newer agents in more and larger RCTs that include clinical endpoints.

Neurocardiology. Neurogenic syncope.

Neurogenic syncope is one of the most frequent causes of recurrent syncope in patients with structurally normal heart. The mechanisms leading to neurogenic syncope remain poorly understood. Evidence recently obtained from several laboratories suggests that impaired arterial baroreflex adaptation to orthostatic stress, in addition to cessation of vasoconstrictive sympathetic traffic, contributes to the development of hypotension and bradycardia that determine the vasovagal response. Neurogenic syncope encompasses a wide range of reflexogenic syncope that includes the vasovagal type, micturition syncope, carotid sinus hypersensitivity and post-prandial syncope. Head-up tilt testing has become the diagnostic tool of choice for the evaluation of patients with recurrent neurogenic syncope, providing an acceptable sensitivity and high specificity that is largely dependent on the type of tilt protocol used to induce neurogenic syncope. This chapter will review the pathophysiology, diagnosis and therapeutic approach to the patient with neurogenic syncope.

Adsorptive stripping behaviour of mitoxantrone on carbon paste electrodes.

The electrooxidation of mitoxantrone (MXT) on carbon paste electrodes was studied using voltammetric techniques in adsorption conditions. The analyte was accumulated at the working electrode (a carbon paste electrode) under precisely controlled mass-transport conditions and stripped electrochemically in the same solution. An electrode pretreatment is proposed which shows good reproducibility of the analytical signal (0.81%). The stripping step was studied with alternating current voltammetry providing a linear response in the concentration range 5 x 10(-11) to 7 x 10(-10)M in aqueous samples. Finally, a method using the medium exchange and AC phase-selective adsorptive stripping voltammetry technique was proposed for MXT analysis in urine samples.

Adsorptive stripping voltammetric behaviour of mitoxantrone on mercury electrodes.

The electrochemical behaviour of mitoxantrone (MXT), an important antineoplastic agent, has been studied at mercury electrodes. The nature of the process taking place at the hanging mercury drop electrode (HMDE) was clarified. The electrochemical behaviour observed was in close agreement with theoretical predictions for an adsorbed molecule which is reversibly reduced. Both the molecule and its reduced product appeared to be adsorbed at the surface of the electrode. Adsorptive stripping voltammetry has been proven to be advantageous over any other assay technique, allowing 5 x 10(-11)M MXT to be detected. The interference arising from surfactants competing for the adsorption sites at the electrode have been studied and the possibility of MXT determination in dilute urine samples has been shown. Some interesting data, such as the MXT adsorbing surface area and the kinetic constant of the associated coupled chemistry reaction were also determined.

Determination of mitoxantrone by flow injection analysis using an amperometric detector.

Mitoxantrone was determined by flow injection analysis using a flow cell modified in the laboratory and fitted with carbon paste as an amperometric detector. The sample solution (100 microliters, 5 x 10(-8)-1 x 10(-5) M) was injected into the carrier stream of 0.1 M perchloric acid (pH 1.12). Mitoxantrone was determined by oxidation at the carbon paste electrode (CPE) at +0.90 V. A 60-cm delay coil (0.5 mm i.d.) was incorporated just before the detector (a canal thin layer) and a flow rate of about 4 ml min-1 was used. The system was successfully applied to the determination of mitoxantrone in a pharmaceutical preparation; the method was fast and reproducible.