Assessment of perfluoroalkyl substances in placenta by coupling salt assisted liquid-liquid extraction with dispersive liquid-liquid microextraction prior to liquid chromatography-tandem mass spectrometry.

The widespread use of perfluoroalkyl substances (PFAS) is resulting in a broad human exposure to these endocrine disrupting chemicals (EDCs), prompting biomonitoring research to evaluate its magnitude and impact, especially during critical windows of exposure such as fetal and perinatal periods. This study was focused on developing a method to determine 10 PFAS in placental tissue by combining salt-assisted liquid-liquid extraction with dispersive liquid-liquid microextraction and using liquid chromatography-tandem mass spectrometry. Chemometric strategies were applied to optimize the experimental parameters. The limit of quantification was 0.02 ng g-1 for all analytes, and the inter-day variability (as relative standard deviation) ranged from 7.9% to 13.8%. Recoveries ranged from 88.2% to 113.9%. The suitableness of the procedure was demonstrated by assessing the targeted compounds in 20 placenta samples. The highest concentrations were recorded for perfluorooctanoic acid and perfluorooctane sulfonate, with maximum concentrations of 0.62 and 1.02 ng g-1 and median concentrations of 0.13 and 0.53 ng g-1, respectively. Median concentrations of the other PFAS ranged from detected values to 0.08 ng g-1. This analytical procedure yields useful data on fetal exposure to PFAS.

Quantification by additive RT-PCR of HIV-1 RNA plasma levels in different stages of HIV-1 infection.

In this study, virion-associated RNA was measured in plasma from twenty six patients in various stages of HIV-1 disease by the additive RT-PCR method. Plasma viral RNA levels were inversely correlated (r = -0.72894) with total CD4+ cell counts and directly (r = 0.86964) with serum titre beta 2-microglobulin in chronically infected patients. This additive RT-PCR is based on a mathematical logistic adjustment of the standard curve and the use of an internal standard identical to the target molecule, which represents a control system for the efficiency of RT-PCR and allows a continuous assessment of the accuracy based on the recovery.

Angiotensin I-converting enzyme genotypes and angiotensin II receptors. Response to therapy.

In the present study, we studied angiotensin II type 1 (AT1) and type 2 (AT2) receptor messengers by quantitative reverse transcriptase-polymerase chain reaction. We examined peripheral blood mononuclear cells from 30 healthy subjects and 50 subjects with primary hypertension, in whom angiotensin I-converting enzyme genotype was determined, before and after 15 days of treatment with different antihypertensive drugs. The medication included a calcium channel antagonist, an angiotensin I-converting enzyme inhibitor, and a beta 1-blocker. We also studied the relationship between AT1 receptor gene expression and biochemical parameters of the renin-angiotensin system. AT1 receptor messenger levels were positively correlated with plasma renin activity in both normotensive and untreated hypertensive subjects. Increases of this messenger and plasma angiotensin II levels were correlated with the D allele in the same individuals. AT1 receptor messenger levels decreased significantly with angiotensin I-converting enzyme inhibitor treatment in subjects with the DD genotype, and a significant decrease was observed in subjects with the II and ID genotypes treated with a calcium antagonist. No changes were observed in mRNA with the beta 1-blocker. We conclude that the AT2 receptor is not expressed in peripheral leukocytes and that AT1 receptor messenger levels vary in relation to angiotensin I-converting enzyme genotype and pharmacological treatment. These results suggest that angiotensin I-converting enzyme genotype may be an important factor when deciding on antihypertensive therapy in individuals with primary hypertension.

Direct quantification of HIV-1 RNA in human plasma by free solution capillary electrophoresis (FSCE).

SUMMARY: The levels of human immunodeficiency virus type 1 (HIV-1) RNA have been directly quantitated, after an isolation step, in plasma from patients with primary HIV-1 infection by free solution capillary electrophoresis (FSCE) with ultraviolet detection. HIV-1 RNA was detected and quantified at physiological levels by measuring the absorbance by FSCE. All the patients with primary infection showed concentrations in a range of 1.08-1.71 x 10(8) virions/ml of plasma. No signals were observed in seronegative donors. This procedure represents a practical alternative to other methods to quantify HIV-1 RNA and may be useful in assessing the efficiency of antiretroviral agents, especially during the early stage when other conventional viral markers are often negative.

Increased expression of scavenger receptor type I gene in human peripheral blood from hyperlipidemic patients determined by quantitative additive RT-PCR.

The scavenger receptors type I and II are mediators for the binding and uptake of chemically modified lipoproteins and are restricted to cells of monocyte origin. These receptors are highly expressed during the process of monocyte to macrophage differentiation. Quantitative mRNA levels of scavenger receptors from peripheral blood mononuclear cells have been analyzed in 29 hyperlipidemic patients and 15 healthy controls. Macrophage scavenger receptor isoforms transcripts were studied in circulating peripheral blood mononuclear cells with a modified RT-PCR method based on the use of a non-modified internal standard and a mathematical logistic adjustment of the standard curve. This method makes it feasible to study the variation in the expression of the scavenger receptors gene in peripheral blood during different physiopathological conditions. We studied the expression of the scavenger receptors gene in different blood cell lines and was present in only those of monocytic origin. The results have shown evidence that levels of scavenger receptor type I transcripts were proportional to apoB/cholesterol levels whereas type II receptors did not show any transcriptional variability. These findings suggest that the cholesterol level exerts a selective up-regulation of the scavenger receptor type I which is detectable by the induced increment of circulating monocytes in the blood of hyperlipidemic patients.

Simultaneous determination of cefepime and L-arginine in injections by second-derivative spectrophotometry.

A simple spectrophotometric assay for the determination of cefepime and L-arginine in injections is described. Since zero-order spectra showed considerable overlap, second-derivative spectrophotometry was used to enhance the spectral details. A linear relationship between second-derivative amplitude and concentration of each compound was found. Beer's law was obeyed up to 50 and 22 micrograms ml-1 of cefepime and arginine, respectively, in the second-derivative mode. Detection limits were 0.31 and 0.58 micrograms ml-1 for cefepime and arginine, respectively. The method, which is rapid, simple and does not require any separation step, has been successfully applied to the assay of commercial injections containing cefepime and arginine.

First and second derivative spectrophotometric determination of cefoperazone and sulbactam in injections.

A simple, spectrophotometric assay to measure the concentrations of cefoperazone and sulbactam in injectable formulations is described. Since zero-order spectra are subject to interference, derivative spectrophotometry was used to enhance the spectral details. A linear relationship between derivative amplitudes and the concentrations of the compounds was found. Beer's law is obeyed up to 75 and 80 micrograms ml-1 of cefoperazone in the first and second derivative modes, respectively, and up to 75 micrograms ml-1 of sulbactam in the second derivative mode. Detection limits were 0.64 and 0.88 microgram ml-1, respectively for cefoperazone in the first and second derivative modes and 0.30 micrograms ml-1 for sulbactam in the second derivative mode. The method is rapid, simple, does not require a separation step and has successfully been applied to the assay of commercial injections containing cefoperazone and sulbactam.

First- and second-derivative spectrophotometric determination of imipenem and cilastatin in injections.

First- and second-derivative spectrophotometry has been used for the quantitation of mixtures of imipenem and cilastatin sodium, compounds that have closely overlapping spectral bands. Beer's law was obeyed at concentrations up to 100 micrograms ml-1 of imipenem in both the first- and second-derivative modes and up to 75 micrograms ml-1 of cilastatin in the first-derivative mode. Detection limits at the P = 0.05 level of significance were calculated to be 0.40 and 0.52 micrograms ml-1 of imipenem and cilastatin sodium, respectively, in the first-derivative mode, and in a range from 0.45 to 0.68 micrograms ml-1 for imipenem in the second-derivative mode. The method, which is rapid, simple and does not require a separation step, has been successfully applied to the assay of commercial injections.

[The prediction of the severity of acute pancreatitis by C-reactive protein]. / Predicción de la severidad de una pancreatitis aguda por la proteína C reactiva.

Reactive C Protein (RCP) has been determined in fifty-one patients with acute pancreatitis. RCP has been compared with Ranson's criteria which include several clinical and biochemical parameters. The value of 20 mg/dl is the one which discriminates serious acute pancreatitis from the mild forms in a 84.3% of patients. Sensitivity and specificity of RCP and Ranson's criteria are compared, the results obtained are similar (88.9% vs. 81.8% and 94.4% vs. 97%). In summary, the determination of RCP is very useful for its simplicity and accuracy in the prognosis of acute pancreatitis.