Microfluidics-based rapid measurement of nitrite in human blood plasma.

Nitric oxide (NO) is one of the vital gasotransmitters that takes part in many biological pathways such as infection, inflammation and ischemia, immune response, neurotransmission, and cardiovascular systems. Nitrite is one of the primary metabolites of NO and is considered to be a circulating storage pool for NO. Here, we report direct and rapid measurement of nitrite in human blood plasma using a fluorescence-based microfluidic method. The study revealed the factors that affect the endogenous concentration of nitrite in blood plasma, mainly the presence of blood cells, hemoglobin, and soluble proteins. We find that separation of blood plasma immediately after sample collection and subsequent dilution of plasma with buffer at a ratio of 1 : 4 eliminates the interference from cells and proteins, providing reliable measurements. The proposed method can measure plasma nitrite in the concentration range of 0-20 µM with a limit of detection of 60 nM and a sensitivity of 5.64 µM-1 within 10 min of sample collection. By spiking nitrite into plasma, a linear correlation between the nitrite concentration and FL intensity is obtained, which is utilized further to measure the endogenous concentration of nitrite present in the plasma of healthy volunteers and patients. The study revealed that the endogenous nitrite concentration in the blood plasma of healthy humans falls in the range of 0.4-1.2 µM. Furthermore, the study with blood samples obtained from patients showed that nitrite levels are inversely correlated with the total cholesterol and low-density lipoproteins levels, which is in good agreement with the literature.

Direct and rapid measurement of hydrogen peroxide in human blood using a microfluidic device.

The levels of hydrogen peroxide ([Formula: see text]) in human blood is of great relevance as it has emerged as an important signalling molecule in a variety of disease states. Fast and reliable measurement of [Formula: see text] levels in the blood, however, continues to remain a challenge. Herein we report an automated method employing a microfluidic device for direct and rapid measurement of [Formula: see text] in human blood based on laser-induced fluorescence measurement. Our study delineates the critical factors that affect measurement accuracy-we found blood cells and soluble proteins significantly alter the native [Formula: see text] levels in the time interval between sample withdrawal and detection. We show that separation of blood cells and subsequent dilution of the plasma with a buffer at a ratio of 1:6 inhibits the above effect, leading to reliable measurements. We demonstrate rapid measurement of [Formula: see text] in plasma in the concentration range of 0-49 µM, offering a limit of detection of 0.05 µM, a sensitivity of 0.60 µM-1, and detection time of 15 min; the device is amenable to the real-time measurement of [Formula: see text] in the patient's blood. Using the linear correlation obtained with known quantities of [Formula: see text], the endogenous [Formula: see text] concentration in the blood of healthy individuals is found to be in the range of 0.8-6 µM. The availability of this device at the point of care will have relevance in understanding the role of [Formula: see text] in health and disease.

Rapid measurement of hydrogen sulphide in human blood plasma using a microfluidic method.

Hydrogen sulfide (H2S) is emerging as an important gasotransmitter in both physiological and pathological states. Rapid measurement of H2S remains a challenge. We report a microfluidic method for rapid measurement of sulphide in blood plasma using Dansyl-Azide, a fluorescence (FL) based probe. We have measured known quantities of externally added (exogenous) H2S to both buffer and human blood plasma. Surprisingly, a decrease in FL intensity with increase in exogenous sulphide concentration in plasma was observed which is attributed to the interaction between the proteins and sulphide present in plasma underpinning our observation. The effects of mixing and incubation time, pH, and dilution of plasma on the FL intensity is studied which revealed that the FL assay required a mixing time of 2 min, incubation time of 5 min, a pH of 7.1 and performing the test within 10 min of sampling; these together constitute the optimal parameters at room temperature. A linear correlation (with R2 ≥ 0.95) and an excellent match was obtained when a comparison was done between the proposed microfluidic and conventional spectrofluorometric methods for known concentrations of H2S (range 0-100 µM). We have measured the baseline level of endogenous H2S in healthy volunteers which was found to lie in the range of 70 µM - 125 µM. The proposed microfluidic device with DNS-Az probe enables rapid and accurate estimation of a key gasotransmitter H2S in plasma in conditions closely mimicking real time clinical setting. The availability of this device as at the point of care, will help in understanding the role of H2S in health and disease.

A Computer Aided Diagnosis System for Identifying Alzheimer's from MRI Scan using Improved Adaboost.

The recent studies in Morphometric Magnetic Resonance Imaging (MRI) have investigated the abnormalities in the brain volume that have been associated diagnosing of the Alzheimer's Disease (AD) by making use of the Voxel-Based Morphometry (VBM). The system permits the evaluation of the volumes of grey matter in subjects such as the AD or the conditions related to it and are compared in an automated manner with the healthy controls in the entire brain. The article also reviews the findings of the VBM that are related to various stages of the AD and also its prodrome known as the Mild Cognitive Impairment (MCI). For this work, the Ada Boost classifier has been proposed to be a good selector of feature that brings down the classification error's upper bound. A Principal Component Analysis (PCA) had been employed for the dimensionality reduction and for improving efficiency. The PCA is a powerful, as well as a reliable, tool in data analysis. Calculating fitness scores will be an independent process. For this reason, the Genetic Algorithm (GA) along with a greedy search may be computed easily along with some high-performance systems of computing. The primary goal of this work was to identify better collections or permutations of the classifiers that are weak to build stronger ones. The results of the experiment prove that the GAs is one more alternative technique used for boosting the permutation of weak classifiers identified in Ada Boost which can produce some better solutions compared to the classical Ada Boost.

Study of soy-fortified green tea curd formulated using potential hypocholesterolemic and hypotensive probiotics isolated from locally made curd.

Recently there has been an increased demand for functional foods to reduce the risk of cardiovascular diseases mainly related to hypercholesterolemia, because of undesirable side effects of traditional drugs (statins). Hence, in the quest for natural and safer alternatives, this work is aimed to bring together the health-promoting properties of probiotics, soymilk, bovine milk and green tea into one product, i.e., soy-fortified green tea curd (GTC). This study includes isolation and characterization of microbes for probiotic attributes, from locally made curd which could reduce cholesterol and produce angiotensin-converting enzyme inhibitors in vitro. The best isolate was used for the production of soy-fortified GTC, and the effect of refrigerated storage on bacterial viability, tea polyphenol contents, and organoleptic properties was investigated. CI1 (Enterococcus faecium) depicted best probiotic potential amongst the 15 isolates. Soy-fortified GTC depicted higher probiotic viability for a longer duration during refrigerated storage and greater ACEI activity than unfortified GTC.

Oxygenation of human blood using photocatalytic reaction.

This report, as a proof of concept, presents the results of oxygenation of human blood using photocatalytic reaction (at lambda = 352 nm) involving the semiconductor thin film junction: tin doped indium oxide (ITO)/nano titanium oxide (TiO2 in anatase structure). These thin films were prepared at room temperature (300 K) on quartz, using reactive DC Magnetron sputtering techniques from pure metallic targets. The results indicate that when 10.0 mL of blood was exposed to ITO/nano TiO2 (14.32 cm surface area) at a wavelength of 352 nm for 120 minutes, the absolute increase in the whole blood oxygen content was 10.13 mL of oxygen per 100.0 mL of blood. This experiment, to our knowledge, is the first of its kind on human blood.