Flow-enhanced nonlinear magnetophoresis for high-resolution bioseparation.

A new mode of transport is described that was capable of high-resolution separation of superparamagnetic materials from complex mixtures based on their size. Laminar flow and a rotating external magnetic field were applied to superparamagnetic beads assembled on a semiperiodic micromagnet array. Beads at the edge of the micromagnet array oscillated in-phase with the external magnetic field with an amplitude that decreased with increasing frequency, ω, until they reached an immobilization frequency, ω(i), where the beads stopped moving. Laminar flow along the edge of the array could be tuned to sweep the beads for which ω < ω(i) downstream at a velocity that increased with size while leaving beads for which ω > ω(i) undisturbed. Flow-enhanced nonlinear magnetophoresis (F-NLM) promises to enable multiple superparamagnetc bead types to be used in the fractionation of cells and implementation of diagnostic assays.

Deal a death blow! HCC in cirrhotics - thrombotic complications: their frequency, characteristics, and risk factors.

INTRODUCTION: The hepatocellular carcinoma (HCC), being the commonest primary cancer, holds the sixth slot in the list of common cancers worldwide. Thrombotic complications in the form of portal vein tumour thrombosis (PVTT) and bland portal vein thrombosis with HCC are common with a bad prognosis. AIM: The study aims to determine the demographic, clinical, and biochemical parameters of HCC patients. The study also compares the clinical and biochemical parameters among patients having HCC with and without thrombotic complication. It further aims to assess the risk factors for thrombotic complication. MATERIAL AND METHODS: This was a retrospective study with a cross sectional design. Clinical and biochemical parameters among patients having HCC with and without thrombotic complication were determined. Tests of statistical significance were applied where a p-value < 0.05 was statistically significant. RESULTS: Overall 118/305 (38.7%) patients of HCC had thrombotic complications. Most of the patients (74.5%) had PVTT whereas in 25.5% bland PVT was found. Higher age, male gender, greater tumour size, advanced stage of HCC (Okuda II, III), multifocal/massive tumour morphology and presence of oesophageal varices, upper GI bleeding, ascites and hepatic encephalopathy, and extrahepatic spread were found to be statistically significant for thrombotic complication (p < 0.05 for each). CONCLUSIONS: Viral related HCC is a commonly reported problem. Thrombotic complication is mainly due to tumour thrombosis rather than bland portal vein thrombosis. Age, gender, greater tumour size, advanced stage of HCC (Okuda II, III), and multifocal/massive tumour morphology were important risk factors for thrombotic complication.

Validation of bioelectrical impedance analysis for assessing dry weight of dialysis patients in Pakistan.

Accurate dry weight estimation (DW) to achieve euvolemia is one of the key objectives of hemodialysis (HD). While conventionally DW is estimated by clinical examination, bioelectrical impedance analysis (BIA) has been proposed as an objective method to determine DW and has been tested extensively in the Western population. We aim to validate BIA for determining DW in a Pakistani population against the conventional clinician's method. This is a single-center validation study conducted at two outpatient HD units of Aga Khan Hospital, Karachi. One hundred and forty-eight DW readings of patients who were on maintenance HD were taken both by BIA technology and by clinical assessment. The clinician was blinded to readings obtained by BIA. Data analysis was carried out using the Statistical Package for Social Sciences (SPSS) version 19. Median age of patients was 63 years (range 12-89). Nearly 54.1% of the samples were female (n = 80). Spearman's correlation between the clinician's estimate and BIA-derived DW showed a correlation coefficient of 0.982, which was statistically significant (P <0.001). This association remained significant when stratified analysis was carried out by dividing the sample into subgroups according to age, gender, body mass index, and total body water content. Inter-rater reliability analysis using the kappa statistics showed almost perfect agreement between the two methods, κ = 0.929 (95% confidence interval, 0.878-0.980, P <0.001). BIA has been validated as a tool for DW assessment of HD patients in Pakistan in comparison to clinical method.

Pulmonary microlithiasis - A case report.

Pulmonary alveolar microlithiasis is a rare diffuse lung disease characterized by widespread sand-like intra-alveolar calcifications (calcospherites composed of calcium and phosphorus). Around 800 cases have been reported in the literature to date. We report here a case of a 35 years old female with prolonged h/o of exertional dyspnoea and mild cough. Clinical examination was mostly normal. Her Chest X-Ray revealed bilateral multiple nodular opacities (sand storm appearance). CT Scan chest showed diffuse micronodular calcifications with septal thickening, compatible with alveolar microlithiasis. Pulmonary function tests showed moderately restrictive lung disease. Bronchoscopic alveolar lavage revealed calcospherites in the alveloli and bronchi confirming the diagnosis of pulmonary alveolar microlithiasis.

Sarcoidosis presented as retroperitoneal and lung mass.

Sarcoidosis is a multisystem granulomatous disorder of unknown aetiology characterised pathologically by the presence of non-caseating granulomas in involved organs. Sarcoidosis most frequently involves the lungs followed by eye and skin. Presentation as retroperitoneal and lung mass is rare in sarcoidosis. We describe an unusual case of sarcoidosis where the patient presented with large retroperitoneal and lung masses, and was treated as tuberculosis.

Circulating tumor cell detection using a parallel flow micro-aperture chip system.

We report on-chip isolation and detection of circulating tumor cells (CTCs) from blood samples using a system that integrates a microchip with immunomagnetics, high-throughput fluidics and size-based filtration. CTCs in a sample are targeted via their surface antigens using magnetic beads functionalized with antibodies. The mixture is then run through a fluidic chamber that contains a micro-fabricated chip with arrays of 8 µm diameter apertures. The fluid runs parallel to the microchip while a magnetic field is generated underneath to draw the beads and cells bound to them toward the chip surface for detection of CTCs that are larger than the apertures and clear out free beads and other smaller particles bound to them. The parallel flow configuration allows high volumetric flow rates, which reduces nonspecific binding to the chip surface and enables multiple circulations of the sample fluid through the system in a short period of time. In this study we first present models of the magnetic and fluidic forces in the system using a finite element method. We then verify the simulation results experimentally to determine an optimal flow rate. Next, we characterize the system by detecting cancer cell lines spiked into healthy human blood and show that on average 89% of the spiked MCF-7 breast cancer cells were detected. We finally demonstrate detection of CTCs in 49 out of 50 blood samples obtained from non-small cell lung cancer (NSCLC) patients and pancreatic cancer (PANC) patients. The number of CTCs detected ranges from 2 to 122 per 8 mL s of blood. We also demonstrate a statistically significant difference between the CTC counts of NSCLC patients who have received therapy and those who have not.