Optimized and scalable synthesis of magnetic nanoparticles for RNA extraction in response to developing countries' needs in the detection and control of SARS-CoV-2.

Ecuador is one of the most affected countries, with the coronavirus disease 2019 (COVID-19) infection, in Latin America derived from an ongoing economic crisis. One of the most important methods for COVID-19 detection is the use of techniques such as real time RT-PCR based on a previous extraction/purification of RNA procedure from nasopharyngeal cells using functionalized magnetic nanoparticles (MNP). This technique allows the processing of ~ 10,000 tests per day in private companies and around hundreds per day at local Universities guaranteeing to reach a wide range of the population. However, the main drawback of this method is the need for specialized MNP with a strong negative charge for the viral RNA extraction to detect the existence of the SARS-CoV-2 virus. Here we present a simplified low cost method to produce 10 g of nanoparticles in 100 mL of solution that was scaled to one litter by parallelizing the process 10 times in just two days and allowing for the possibility of making ~ 50,000 COVID-19 tests. This communication helps in reducing the cost of acquiring MNP for diverse biomolecular applications supporting developing country budgets constraints and chemical availability specially during the COVID-19 International Health Emergency.

Understanding gold toxicity in aerobically-grown Escherichia coli.

BACKGROUND: There is an emerging field to put into practice new strategies for developing molecules with antimicrobial properties. In this line, several metals and metalloids are currently being used for these purposes, although their cellular effect(s) or target(s) in a particular organism are still unknown. Here we aimed to investigate and analyze Au3+ toxicity through a combination of biochemical and molecular approaches. RESULTS: We found that Au3+ triggers a major oxidative unbalance in Escherichia coli, characterized by decreased intracellular thiol levels, increased superoxide concentration, as well as by an augmented production of the antioxidant enzymes superoxide dismutase and catalase. Because ROS production is, in some cases, associated with metal reduction and the concomitant generation of gold-containing nanostructures (AuNS), this possibility was evaluated in vivo and in vitro. CONCLUSIONS: Au3+ is toxic for E. coli because it triggers an unbalance of the bacterium's oxidative status. This was demonstrated by using oxidative stress dyes and antioxidant chemicals as well as gene reporters, RSH concentrations and AuNS generation.

Understanding gold toxicity in aerobically-grown Escherichia coli

BACKGROUND: There Is an emerging field to put Into practice new strategies for developing molecules with antimicrobial properties. In this line, several metals and metalloids are currently being used for these purposes, although their cellular effect(s) or target(s) in a particular organism are still unknown. Here we aimed to investigate and analyze Au3+ toxicity through a combination of biochemical and molecular approaches. RESULTS: We found that Au3+ triggers a major oxidative unbalance in Escherichia coli, characterized by decreased intracellular thiol levels, increased superoxide concentration, as well as by an augmented production of the antioxidant enzymes superoxide dismutase and catalase. Because ROS production is, in some cases, associated with metal reduction and the concomitant generation of gold-containing nanostructures (AuNS), this possibility was evaluated in vivo and in vitro. CONCLUSIONS: Au3+ is toxic for E. coli because it triggers an unbalance of the bacterium's oxidative status. This was demonstrated by using oxidative stress dyes and antioxidant chemicals as well as gene reporters, RSH concentrations and AuNS generation.

Microsomal oxidative stress induced by NADPH is inhibited by nitrofurantoin redox biotranformation.

Nitrofurantoin is used in the antibacterial therapy of the urinary tract. This therapy is associated with various adverse effects whose mechanisms remain unclear. Diverse studies show that the nitro reductive metabolism of nitrofurantoin leads to ROS generation. This reaction can be catalyzed by several reductases, including the cytochrome P450 (CYP450) reductase. Oxidative stress arising from this nitro reductive metabolism has been proposed as the mechanism underlying the adverse effects associated with nitrofurantoin. There is, however, an apparent paradox between these findings and the ability of nitrofurantoin to inhibit lipid peroxidation provoked by NADPH in rat liver microsomes. This work was aimed to show the potential contribution of different enzymatic systems to the metabolism of this drug in rat liver microsomes. Our results show that microsomal lipid peroxidation promoted by NADPH is inhibited by nitrofurantoin in a concentration-dependent manner. This suggests that the consumption of NADPH in microsomes can be competitively promoted by lipid peroxidation and nitrofurantoin metabolism. The incubation of microsomes with NADPH and nitrofurantoin generated 1-aminohidantoin. In addition, the biotransformation of a classical substrate of CYP450 oxidative system was competitively inhibited by nitrofurantoin. These results suggest that nitrofurantoin is metabolized through CYP450 system. Data are discussed in terms of the in vitro redox metabolism of nitrofurantoin.

The role of attention in Wisconsin Card Sorting Test performance.

The present study sought to test the hypothesis that the second factor (consisting of Failure-to-Maintain-Set and other scores) found in two recent factor analyses of the Wisconsin Card Sorting Test reflects attentional function. The effect of color overlays (an experimental manipulation known to influence neural systems linked to attention) was examined in 17 normal control and 14 attention-disordered children (ages 8 to 12). Group and Color main effects were found for Factor 1 (which consists largely of measures of perseveration) and a Color main effect was observed for Factor 2. The Color effect for Factor 2 supported the contention that this factor reflects attentional processes. A hypothesis concerning the relationship between problem solving and attention on the WCST is offered and a means for testing it is discussed.

[Caroli's disease. Presentation of 8 cases studied with ERCP]. / Enfermedad de Caroli. Aportación de ocho casos estudiados por CPRE.

Eight patients with Caroli's Disease are presented, studied by Endoscopic Retrograde Cholangiopancreatography (ERCP) from January 1976 through January 1990. In this period of time 1,525 procedures were carried out, this entity thus representing 0.52% of patients submitted to ERCP in our population. Six patients were females, being female: male ratio 3:1. Mean age was 52 years (range: 40-75). All patients presented a clinical history of recurring episodes of abdominal pain and/or crisis of cholangitis. In the ERCP carried out in these eight patients, cystic dilatation of intrahepatic left lobe bile ducts were confirmed in five patients, dilatation generalized to both lobes in two, and affecting exclusively the right lobe in one patient.

[Immunological and biochemical factors associated with spontaneous bacterial peritonitis]. / Factores inmunológicos y bioquímicos relacionados con la peritonitis bacteriana espontánea.

A prospective study (June 1988-December 1989) of all patients admitted with ascites due to cirrhosis was undertaken: Biochemical and immunological factors which may have significance in the development of spontaneous bacterial peritonitis were determined. Among 56 patients (44 males and 12 females) SBP developed in 16% of the group. No age differences were found and the etiology of the cirrhosis was mainly alcoholic. Patients with SBP had lower alpha-2 globulin concentrations: 0.43 +/- 0.12 vs. 0.60 +/- 0.18 g/dl (p less than 0.05) and a lower prothrombin time: 41 +/- 13% vs. 69.5 +/- 13 vs. 69.5 +/- 21% (p less than 0.001). Patients with SBP had also lower ascitic fluid total protein 0.99 +/- 0.4 vs. 1.64 +/- 1.1 g/dl (p less than 0.01) as well as lower alfa-2 globulin: 0.065 +/- 0.012 vs. 0.096 +/- 0.067 g/dl (p less than 0.05); beta globulin, 0.11 +/- 0.047 vs. 0.2 +/- 0.17 g/dl (p less than 0.05); gamma globulin, 0.32 +/- 0.1 vs. 0.52 +/- 0.4 g/dl (p less than 0.05); IgG, 275 +/- 157 vs. 477 +/- 335 g/dl (p less than 0.05); C3, 9.2 +/- 3.2 vs. 17 +/- 13 mg/dl (p less than 0.01) and C4, 2.83 +/- 1.5 vs. 4.66 +/- 3.9 mg/dl (p less than 0.05) than patients without this complication.

[Fournier's disease: a report of 9 cases]. / Enfermedad de Fournier: aportación de nueve casos.

Nine cases of Fournier's gangrene diagnosed between 1982 and 1989 are reported. All were males with a mean age of 76 (47-82 years). Seven had a history of alcoholism and one had non insulin-dependent diabetes. Six patients also had an anal fistula which may have been the starting point of the infection. The causal agents were two anaerobes (Clostridium perfringens and Bacteroides fragilis) two gram-negatives (Morganella morgagni and Pseudomonas aeruginosa) and one, an unidentified gram-positive. In three patients a mixed intestinal flora was isolated and in another no germs were found. All were treated with broad-spectrum antibiotics and surgery. Seven patients survived and two died.

[Presenting forms and diagnostic procedures in gigantic hemangioma of the liver]. / Formas de presentación y procedimientos diagnósticos del hemangioma hepático gigante.

We present eleven patients diagnosed of giant hepatic hemangioma in the last 20 years. The diagnosis was confirmed in all the cases during laparoscopy or laparotomy. The mean age of the patients was 44.9 +/- 8.99; nine of them were women. Only two of the patients complained of abdominal pain. Five patients showed abnormal liver function tests; the most common finding was increased levels of alkaline phosphatase. We have reviewed the diagnostic tools employed: isotopic study of the liver with 99Tc, and labeled erythrocytes, abdominal ultrasonography, CAT, hepatic arteriography, laparoscopy, laparotomy and liver biopsy. Usually we employed more than one of these diagnostic methods. In the last years there has been a shift to employ less invasive procedures.