Development of microwave assisted-UV digestion using diluted reagents for the determination of total nitrogen in cereals by ion chromatography

The objective of this work is to develop a microwave assisted-ultraviolet (MW-UV) digestion in the presence of dilute HCl and H₂O₂ followed by ion chromatography (IC) measurements for the determination of total nitrogen in cereals. This approach (MW-UV-IC) requires lesser time and does not need environmentally hazardous materials as used in Kjeldhal method. Further, the developed method requires only microliter quantities of dilute HCl and few milliliters of H₂O₂ for the matrix digestion and simultaneous conversion of nitrogen to its ionic species for the subsequent analysis by IC. At the optimized acid concentrations (200 ​μL of 0.1 ​mol ​L^-1 HCl) and microwave power, the nitrogen in the cereals flours is converted to nitrate (NO₃ ^-), nitrite (NO₂ ^-) and ammonium (NH₄ ⁺) ions. The nitrogen species were separated using IonPac AS-20 and IonPac CS-17 columns and then quantified using suppressed conductivity detection. The method was applied to estimate the total nitrogen in flours of various cereals like; wheat (Triticum aestivum), rice (Oryza sativa), finger millet (Eleusine coracana), jowar (Sorghum) and pearl millet (Pennisetum glaucum). The results obtained using proposed method, were in good agreement with that of Kjeldhal method. Further, the precision of the values obtained by developed method was on par with the Kjeldhal method for all the tested flours as verified by F-test (n ​= ​5 and 95% confidence limit). Additionally, greenness assessment tools like analytical Eco-scale and green analytical procedure index (GAPI) suggested the proposed MW-UV-IC method, for the determination of total nitrogen in cereal flours, to be excellently green and safe.

Determination of Low-Level Pesticide Residues in Soft Drinks and Sports Drinks by Liquid Chromatography with Tandem Mass Spectrometry: Collaborative Study

A collaborative study was conducted on a method for the measurement of 11 low-level pesticide residues in soft drinks and sports drinks by liquid chromatography with tandem mass spectrometry. The pesticide residues determined in this study were alachlor, atrazine, butachlor, isoproturon, malaoxon, monocrotophos, methyl paraoxon, phorate, phorate sulfone, phorate sulfoxide, and 2,4-dichlorophenoxyacetic acid (2,4-D). Blind fortification solutions containing 3 different levels of pesticide residues were provided to 9 collaborating laboratories to create test samples at concentrations of 0, 0.1, and 0.5 g/L with a 10-fold concentration for phorate in a total of 6 matrixes (2 colas, 1 diet cola, 1 clear lemon-lime soft drink, 1 orange soft drink, and 1 sports drink). Good qualitative performance of the method was demonstrated for all pesticide residues. Reproducibility relative standard deviation (RSDR) ranged from 7 to 151 for alachlor, atrazine, butachlor, isoproturon, malaoxon, monocrotophos, methyl paraoxon, phorate, phorate sulfone, phorate sulfoxide, and 2,4-D at the 0.1 g/L level (1.0 g/L for phorate). At 0.5 g/L (5.0 g/L for phorate), RSDR ranged from 9 to 57 for alachlor, atrazine, butachlor isoproturon, malaoxon, monocrotophos, methyl paraoxon, phorate, phorate sulfone, phorate sulfoxide, and 2,4-D in all matrixes. Repeatability relative standard deviation (RSDr), applicable to the diet cola and sports drink, ranged from 0 to 124 for the 11 pesticide residues at the 0.1 g/L level (1.0 g/L for phorate). At 0.5 g/L (5.0 g/L for phorate), RSDr ranged from 4 to 26. Recoveries for the 11 pesticide residues in all matrixes ranged from 84 to 300 at the 0.1 g/L level (1.0 g/L for phorate) and from 66 to 127 at the 0.5 g/L (5.0 g/L for phorate) level. Coefficients of determination (r2) of the matrix-matched calibration curves were 0.95. It is recommended that the method be accepted by AOAC as Official First Action with a limit of quantification of 0.5 g/L for alachlor, atrazine, butachlor, isoproturon, malaoxon, methyl paraoxon, monocrotophos, phorate sulfone, phorate sulfoxide, and 2,4-D and 5.0 g/L for phorate.

Detection of Chlamydia pneumoniae DNA in CD3+ lymphocytes from healthy blood donors and patients with coronary artery disease

BACKGROUND

Chlamydia pneumoniae is an intracellular bacterium responsible for respiratory tract infections. Recent studies have implicated this organism in the pathogenesis of atherosclerosis.

METHODS AND RESULTS

To address how the organism is transported from lungs to cardiac vessels, we characterized the cell population within peripheral blood mononuclear cells (PBMCs) that harbor C pneumoniae DNA. Adherent and nonadherent PBMCs from 28 patients with coronary artery disease (CAD) and 19 healthy blood donors were evaluated for the presence of C pneumoniae DNA by touchdown nested polymerase chain reaction (nPCR). Of the 28 patients, 10 (36%) had detectable PCR product in their nonadherent and 3 (10%) in their adherent PBMC population. C pneumoniae-specific PCR results were positive for 5 of 19 (26%) healthy blood donors. PCR positivity was detected only in the nonadherent cell population among this group of individuals. Fractionation of nonadherent PBMCs identified C pneumoniae-specific PCR signal among the CD3+ T-cell population exclusively. Of the 18 PCR-positive subjects (13 patients and 5 healthy control subjects), 67% (8 patients and 4 healthy blood donors) tested positive for C pneumoniae-specific IgG serology. Interestingly, 2 patients became PCR negative on a repeated blood draw 5 months after initial detection of C pneumoniae DNA despite retaining C pneumoniae-specific antibodies.

CONCLUSIONS

Our results demonstrate marginally significant prevalence of C pneumoniae DNA in patients with CAD compared with healthy subjects (P=0.082). In contrast, the prevalence of IgG seropositivity among the 2 groups did not reach statistical significance (P=0.306). We also provide unequivocal evidence for the presence of C pneumoniae DNA predominantly among the circulating CD3+ T-cell population.

Evaluation of low-risk patients with chest pain in the emergency department: value and limitations of recent methods

More than 2 million patients are hospitalized annually in this country because of chest pain suggestive of myocardial ischemia. However, a coronary event is demonstrated in <20% of this population. It has been further shown that among patients presenting with acute chest pain, a very low-risk group, with <5% probability of a coronary event, can be identified by the initial clinical assessment. Recognition of this group could prevent many unnecessary hospital admissions, affording more appropriate patient care and improved cost-effectiveness. To enhance identification and management of low-risk patients with chest pain, several diagnostic approaches are currently being investigated to determine their value in the early detection of myocardial ischemia to select those requiring admission. In addition to the initial history, these strategies include physical examination and electrocardiogram, new serum markers, early noninvasive cardiac imaging by echocardiography or myocardial scintigraphy, new electrocardiographic methods, and early exercise testing. Most of these methods have shown promise for stratifying patients presenting with chest pain into high-risk and low-risk groups, thereby extending the initial clinical assessment in the critical decision of patient admission or discharge from the emergency department with early follow-up. This review presents the current status of these techniques with emphasis on our experience with immediate treadmill testing of selected patients in the emergency department. These methods are still in the developmental phase and their long-term utility will be determined by their safety, accuracy, cost, and specific institutional expertise.

Management of cardiac complications in neuromuscular disease

Cardiovascular complications are common and varied in neuromuscular diseases. Knowledge of the complications specific to each disease is essential for appropriate screening for cardiovascular disease. Appropriate treatment of complications varies between neuromuscular diseases and draws primarily on experience from patients without neuromuscular disease. This article details the known cardiovascular complications and treatments for some of the major neuromuscular diseases.