A real-time characterization method to rapidly optimize molecular beacon signal for sensitive nucleic acids analysis.

This research demonstrates an integrated microfluidic titration assay to characterize the cation concentrations in working buffer to rapidly optimize the signal-to-noise ratio (SNR) of molecular beacons (MBs). The "Microfluidic Droplet Array Titration Assay" (MiDATA) integrated the functions of sample dilution, sample loading, sample mixing, fluorescence analysis, and re-confirmation functions all together in a one-step process. It allows experimentalists to arbitrarily change sample concentration and acquire SNR measurements instantaneously. MiDATA greatly reduces sample dilution time, number of samples needed, sample consumption, and the total titration time. The maximum SNR of molecular beacons is achieved by optimizing the concentrations of the monovalent and divalent cation (i.e., Mg(2+) and K(+)) of the working buffer. MiDATA platform is able to reduce the total consumed reagents to less than 50 µL, and decrease the assay time to less than 30 min. The SNR of the designated MB is increased from 20 to 126 (i.e., enhanced the signal 630 %) using the optimal concentration of MgCl2 and KCl determined by MiDATA. This novel microfluidics-based titration method is not only useful for SNR optimization of molecular beacons but it also can be a general method for a wide range of fluorescence resonance energy transfer (FRET)-based molecular probes.

Usefulness of Functional Thyroid-Stimulating and Thyroid-Blocking Immunoglobulin Bioassays in an Atypical Presentation of Graves' Disease.

Background/Objective: Thyroid-stimulating hormone (TSH) receptor antibody (TRAb) is well recognized as the pathogenic antibody that causes the clinical manifestation of Graves' disease (GD). Although the majority of TRAb measured in GD is due to thyroid-stimulating immunoglobulin (TSI), there are other functional classes of TRAb, ie, thyroid-blocking immunoglobulin (TBI) and neutral antibodies, which can alter the clinical course of the disease. We present a case of a patient who demonstrated interesting coexistence of both the forms using Thyretain TSI and TBI Reporter BioAssays. Case Report: A 38-year-old woman presented with thyrotoxicosis (TSH level, 0.01 mIU/L, free thyroxine level, >7.8 ng/mL [>100 pmol/L], and free triiodothyronine level, >32.6 pg/mL [>50 pmol/L]) to her general practitioner. She was treated with 15-mg carbimazole twice daily before the dose was reduced to 10 mg. Four weeks later, she developed severe hypothyroidism, with a TSH level of 57.5 mIU/L, free thyroxine level of 0.5 ng/mL (6.7 pmol/L), and free triiodothyronine level of 2.6 pg/mL (4.0 pmol/L). Carbimazole was ceased; however, she remained severely hypothyroid, with a TRAb level of 35 IU/L. Both TSI (304% signal-to-reference ratio) and TBI (56% inhibition) were present, with predominance of the blocking form of thyroid receptor antibodies (54% inhibition). Thyroxine was commenced, and her thyroid functions remained steady and TSI became undetectable. Discussion: The results of the bioassays confirmed that both TSI and TBI can coexist in a patient and that its action changes within a short period of time. Conclusion: Clinicians and laboratory scientists should be aware of the usefulness of TSI and TBI bioassays in the interpretation of atypical presentations of GD.

Comparison of a subcutaneous versus intravenous insulin protocol for managing hyperglycemia following antenatal betamethasone in women with diabetes: a pilot randomized controlled trial.

INTRODUCTION: Evaluate the safety and efficacy of a subcutaneous insulin (SC-I) versus intravenous insulin (IV-I) protocol for optimizing maternal blood glucose levels (BGLs) post-betamethasone administration. METHODS: Randomized controlled in-patient pilot study in pregnant women with diabetes, excluding type 1 diabetes, receiving betamethasone ≥24 weeks' gestation. Interventions were stratified SC-I and IV-I protocols, titrated to hourly BGLs (IV-I) or predicted maternal hyperglycemia and 2-4 hourly BGLs (SC-I). Primary outcome was percentage at-target BGL 4.0-8.0 mmol/L over 48 h post-betamethasone. Secondary outcomes were rates of maternal hyperglycemia (>8.0 mmol/L), hypoglycemia (<4.0 mmol/L) and neonatal hypoglycemia (≤2.5 mmol/L). RESULTS: 19 women (3 with type 2 diabetes [T2DM], 4 with gestational diabetes [GDM]-diet, 12 GDM-insulin) were randomized to a SC-I (n = 13) or IV-I (n = 6) protocol in a 9-month period. There was a non-significant trend for higher mean percentage at-target BGLs with SC-I vs IV-I (87% vs 81%; p = .055); this was significant when the cohort was restricted to women with GDM (89% vs 81%; p = .04). Maternal hyperglycemia (85% vs 100%; p = .31) and hypoglycemia (54% vs 33%; p = .41) were not significantly different, but there were no BGLs <3.8 mmol/L with IV-I (vs 4 women with SC-I; p = .13). The rate of neonatal hypoglycemia was not different between groups. CONCLUSION: A SC-I or IV-I protocol controls maternal BGLs following betamethasone, but SC-I appears safe and minimizes labor intensive IV-I in GDM. An adequately powered RCT to assess superiority of SC-I is planned.

Nonviral gene vector formation in monodispersed picolitre incubator for consistent gene delivery.

A novel picolitre incubator based microfluidic system for consistent nonviral gene carrier formulation is presented. A cationic lipid-based carrier is the most attractive nonviral solution for delivering plasmid DNA, shRNA, or drugs for pharmaceutical research and RNAi applications. The size of the cationic lipid and DNA complex (CL-DNA), or the lipoplex, is one of the important variations for consistency of gene transfection. CL-DNA size, in turn, may be controlled by factors such as the cationic lipid and DNA mixing order, mixing rate, and mixture incubation time. The Picolitre Microfluidic Reactor and Incubator (PMRI) system described here is able to control these parameters in order to create homogeneous CL-DNA. Compared with conventional CL-DNA preparation techniques involving hand-shaking or vortexing, the PMRI system demonstrates a greater ability to constantly and uniformly mix cationic lipids and DNA simultaneously. After mixing in the picolitre droplet reactors, the cationic lipid and DNA is incubated within the picolitre incubator to form CL-DNA. The PMRI generates a narrower size distribution band, while also turning the sample loading, mixing and incubation steps into an integrated process enabling the consistent formation of CL-DNA. The coefficient of variation (CV) of transfection efficiency is 0.05 and 0.30 for PMRI-based and conventional methods, respectively. In addition, this paper demonstrates that the gene transfection efficiency of lipoplex created in the PMRI is more reproducible.

Liver enzyme profile and progression in association with thyroid autoimmunity in Graves' disease.

OBJECTIVE: To investigate the associations of Graves' disease (GD) severity, autoimmunity and longitudinal liver enzyme changes with time in a cohort with well-characterized GD. DESIGN: Retrospective cohort study. PATIENTS: Patients diagnosed with Graves' disease, treated at Royal Prince Alfred Hospital Sydney, Adult Thyroid Clinic from 2000 to 2012 inclusive. MEASUREMENTS: Inclusion criteria were patients with a complete set of TSH, FT4, FT3, liver enzymes and TSH receptor antibody (TRAb) results prior to commencement of thionamide therapy. RESULTS: Of the 146 patients who had complete results, 69 (47%) had at least one abnormal liver enzyme. Gamma glutamyltransferase (GGT) was most frequently abnormal (74%), followed by alanine aminotransferase (ALT) (57%), alkaline phosphatase (ALP) (39%) and then aspartate aminotransferase (AST) (29%). Subsequent to thyroid function normalization, 78% of the liver enzymes were normalized, 10% were persistently abnormal and 12% were lost to follow-up. Circulating TRAb, FT3 and FT4 results were categorized into mild, moderate and severe elevations. At univariate regression analyses, TRAb, FT3 and FT4 levels were each significantly associated with abnormal liver enzyme profile. Multivariate regression including TRAB, FT3 and FT4 as independent variables demonstrated FT3 and FT4 were more strongly associated with abnormal liver profile than TRAb. However, the initial FT3 and FT4 levels were not associated with abnormal liver profile in the subgroup with persistently abnormal liver profile. CONCLUSION: Graves' disease is commonly associated with abnormal liver enzymes, and most commonly with abnormal levels of GGT, and that an abnormal liver enzyme profile is more directly linked to the degree of thyrotoxicosis than levels of TRAB.

Growth and maturation of cardiac myocytes in fetal sheep in the second half of gestation.

Right (RVFW) and left (LVFW) ventricular free wall cardiac myocytes were collected from 25 fetal sheep aged 77-146 days gestation (term = 150 days gestation), six saline-infused catheterized fetal sheep (129 GD), and five lambs to measure gestational changes in uni- and binucleated cardiac myocyte numbers and cell volumes by confocal microscopy. At 77 days gestation, 2% of the myocytes were binucleated, which increased to 50% at 135 days gestation and 90% at 4-6 weeks after birth. RVFW uni- and binucleated myocytes were larger than those in the LVFW, and cell volumes of RVFW uni- and binucleated and LVFW binucleated myocytes (but not LVFW uninucleated myocytes) increased with gestation. Before birth, the approximate number of myocytes was greater in the LVFW than in the RVFW (P < 0.001). Before 110 GD, cardiac growth appeared to be due to myocyte hyperplasia, as approximate myocyte numbers and VFW weight increased at the same rate. After 110 days gestation, the approximate myocyte number/g VFW weight decreased, which suggests that myocyte hypertrophy, as well as hyperplasia, was occurring in association with the appearance of a greater proportion of binucleated cells after that time. By 4-6 weeks of age, there was marked hypertrophy of myocytes and an apparent reduction in myocyte number.

1-Million droplet array with wide-field fluorescence imaging for digital PCR.

Digital droplet reactors are useful as chemical and biological containers to discretize reagents into picolitre or nanolitre volumes for analysis of single cells, organisms, or molecules. However, most DNA based assays require processing of samples on the order of tens of microlitres and contain as few as one to as many as millions of fragments to be detected. Presented in this work is a droplet microfluidic platform and fluorescence imaging setup designed to better meet the needs of the high-throughput and high-dynamic-range by integrating multiple high-throughput droplet processing schemes on the chip. The design is capable of generating over 1-million, monodisperse, 50 picolitre droplets in 2-7 minutes that then self-assemble into high density 3-dimensional sphere packing configurations in a large viewing chamber for visualization and analysis. This device then undergoes on-chip polymerase chain reaction (PCR) amplification and fluorescence detection to digitally quantify the sample's nucleic acid contents. Wide-field fluorescence images are captured using a low cost 21-megapixel digital camera and macro-lens with an 8-12 cm(2) field-of-view at 1× to 0.85× magnification, respectively. We demonstrate both end-point and real-time imaging ability to perform on-chip quantitative digital PCR analysis of the entire droplet array. Compared to previous work, this highly integrated design yields a 100-fold increase in the number of on-chip digitized reactors with simultaneous fluorescence imaging for digital PCR based assays.