Analysis of natural flavonoids by microchip-micellar electrokinetic chromatography with pulsed amperometric detection.

Catechins (catechin and other derivatives) are naturally occurring flavonoids present in a number of plants and foods. They are also part of numerous nutraceutical formulations because they are believed to have antioxidant, cancer chemo-preventative, anti-inflammatory and antimicrobial properties. The determination of catechins has traditionally been performed by HPLC.

Determination of levoglucosan from smoke samples using microchip capillary electrophoresis with pulsed amperometric detection.

Separation and detection of native anhydrous carbohydrates derived from the combustion of biomass using an electrophoretic microchip with pulsed amperometric detection (PAD) is described. Levoglucosan represents the largest single component of the water extractable organics in smoke particles and can be used to trace forest fires or discriminate urban air pollution sources. Detection of levoglucosan and other sugar anhydrides in both source and ambient aerosol samples is typically performed by gas chromatographic (GC) separation with mass spectrometric (MS) detection.

Comparison of surfactants for dynamic surface modification of poly(dimethylsiloxane) microchips.

In the present report, the use of negatively charged surfactants as modifiers of the background electrolyte is reported using poly(dimethylsiloxane) (PDMS) microchips. In particular, the use of anionic surfactants, such as sodium dodecyl sulfate, phosphatidic acid, and deoxycholate, was studied. When surfactants were present in the run buffer, an increase in the electroosmotic flow (EOF) was observed.

Spectrum of hypertensive emergencies in pregnancy.

Hypertension in pregnancy represents a spectrum of clinical entities, including pregnancy-induced hypertension (PIH), preeclampsia, eclampsia, and hemolysis, elevated liver enzyme levels, low platelet count syndrome. Although hypertension is a common denominator in this group of disorders, the pathogenesis, clinical features, and clinical course of these disorders is variable and somewhat distinct. Therapy must be tailored to the clinical entity and the patient.

Determinants and prognostic importance of cardiomegaly among new ESRD patients in the United States.

Purpose: Cardiomegaly is a radiographic abnormality of major prognostic importance in the general population. We explored the clinical correlations and mortality impact of cardiomegaly in new end-stage renal disease (ESRD) patients from the Dialysis Morbidity and Mortality Study Wave 2.

Methods: Radiographic data denoting the presence or absence of cardiomegaly were available for 97% (n=3908) of the entire cohort.

Insight in psychosis: a systematic review of treatment interventions.

Insight into illness is often impaired in psychosis and associated with poor prognosis, yet little is known about how to improve insight. After an examination of the conceptual background of insight, we review the limited empirical studies of this topic. Six studies of psychoeducation are mixed, though suggesting a possible benefit, especially with individualized interventions.

Direct detection of renal function markers using microchip CE with pulsed electrochemical detection.

Creatinine, creatine, and uric acid are three important compounds that are measured in a variety of clinical assays, most notably for renal function. Traditional clinical assays for these compounds have focused on the use of enzymes or chemical reactions. Electrophoretic microchips have the potential to integrate separation power of capillary electrophoresis with devices that are small, portable, and have the speed of conventional sensors.

Comparison of the safety and efficacy of dorzolamide 2% and brimonidine 0.2% in patients with glaucoma or ocular hypertension.

Purpose: To compare the intraocular pressure (IOP) reduction between dorzolamide 2% and brimonidine 0.2% in primary open-angle glaucoma (POAG) or ocular hypertension (OHT).

Methods: This study was a prospective, double-masked, randomized, crossover comparison of dorzolamide 2% (Trusopt) and brimonidine 0.

Versatile 3-channel high-voltage power supply for microchip capillary electrophoresis.

The fabrication of a battery operated 3-channel high voltage power supply for microchip capillary electrophoresis is described. The power supply consists of two positive and one negative DC-DC converters, a microprocessor controlled timer, a battery and a transformer to recharge the battery and feed the high voltage relays. This arrangement allows the possibility to control the potentials applied in the 0 to +/-4000 V range to a variety of microchip setups.

Simple and sensitive electrode design for microchip electrophoresis/electrochemistry.

A simple and sensitive electrode design for microchip capillary electrophoresis/electrochemistry (CE-EC) is presented. The system employs metal microwires as the working electrodes for electrochemical detection. Two general approaches for integration of electrodes in microchip CE-EC are commonly used, end-channel and microfabrication.

Long-term outcome with divalproex in children and adolescents with bipolar disorder.

Objective: To assess the outcome and safety of divalproex treatment in children and adolescents with bipolar disorder.

Methods: We conducted a chart review of children and adolescents who were treated with divalproex and who met Diagnostic and Statistical Manual of Mental Disorders, fourth edition, criteria for bipolar disorder (dose 966 +/- 501 mg/day, level 79.4 +/- 23.

Direct determination of carbohydrates, amino acids, and antibiotics by microchip electrophoresis with pulsed amperometric detection.

The separation and detection of underivatized carbohydrates, amino acids, and sulfur-containing antibiotics in an electrophoretic microchip with pulsed amperometric detection (PAD) is described. This report also describes the development of a new chip configuration for microchip electrophoresis with PAD. The configuration consists of a layer of poly(dimethylsiloxane) that contains the microfluidic channels, reservoirs, and a gold microwire, sealed to a second layer of poly(dimethylsiloxane).

Measuring protein interactions by microchip self-interaction chromatography.

The self-interaction of proteins is of paramount importance in aggregation and crystallization phenomena. Solution conditions leading to a change in the state of aggregation of a protein, whether amorphous or crystalline, have mainly been discovered by the use of trial and error screening of large numbers of solutions. Self-interaction chromatography has the potential to provide a quantitative method for determination of protein self-interactions amenable to high-throughput screening.

Screening of protein-ligand interactions by affinity chromatography.

This paper examines affinity chromatography (AC) as an alternative tool for the determination of protein-ligand interactions for the particular case in which the ligand is the same protein. The methodology is less labor-intensive and more sample-efficient than traditional methods used to measure the second virial coefficient (B(22)), a parameter commonly used to evaluate protein-protein interactions. The chromatographic capacity factor (k') was studied for lysozyme and equine serum albumin for a wide range of experimental solution conditions such as crystallizing agent concentration, protein concentration and pH.

Experimental studies of electroosmotic flow dynamics in microfabricated devices during current monitoring experiments.

Electroosmotic flow (EOF) was monitored in glass microfluidic devices at rates up to 2 Hz with a precision of 0.2-1.0% using a technique based on the periodic photobleaching of a dilute, neutral fluorophore added to the running buffer.

The inheritance of mating songs in two cryptic, sibling lacewing species (Neuroptera: Chrysopidae: Chrysoperla).

Speciation often involves incremental responses to natural selection and results in large scale genomic changes, but it may also occur abruptly and with little genetic imprint, as seen in some complexes of cryptic species. Recent attention has focused on sexual selection in rapid speciation, because it can disrupt premating signals that mediate reproductive isolation. Some models require that environmental adaptation assist sexual selection during speciation, while others show that populations can diverge through mate choice alone.

Recovery trajectories after in situ burning of an oiled wetland in coastal Louisiana, USA.

The high degree of physical disturbance associated with conventional response options to oil spills in wetlands is driving the investigation of alternative cleanup methodologies. In March 1995, a spill of gas condensate in a brackish marsh at Rockefeller Wildlife Refuge in southwestern Louisiana was remediated through the use of in situ burning. An assessment of vegetation recovery was initiated in three treatment marshes: (1) oil-impacted and burned, (2) oil impacted and unburned, and (3) a nonoiled unburned reference.

Pulsed amperometric detection of carbohydrates on an electrophoretic microchip.

The first report of pulsed amperometric detection (PAD) on an electrophoretic microchip is presented. A hybrid poly-(dimethylsiloxane)/glass device was coupled with a platinum working electrode for the electrochemical detection of glucose, maltose, and xylose. Under optimized detection conditions, glucose was found to respond linearly from 20 to 500 microM with a measured detection limit of 20 microM.

Analysis of human leukocyte antigens in patients with internal derangement of the temporomandibular joint.

Purpose: Spondyloarthropathy includes the subcategory of reactive arthritis (ReA). Spondyloarthropathies are commonly associated with certain human leukocyte antigen (HLA) alleles. Because we identified bacteria associated with ReA within the temporomandibular joint (TMJ), we now evaluate the frequency of HLA alleles in patients with TMJ pathology.

The analysis of uric acid in urine using microchip capillary electrophoresis with electrochemical detection.

Clinical studies have linked irregular concentrations of uric acid in urine to several diseases. Conventional methods for the measurement of uric acid are however temperature-dependent, expensive, and require labile reagents. The miniaturization of analytical techniques, specifically capillary electrophoresis, offers an ideal alternative for clinical analyses such as uric acid determination.

CONVERGENT EVOLUTION OF COURTSHIP SONGS AMONG CRYPTIC SPECIES OF THE CARNEA GROUP OF GREEN LACEWINGS (NEUROPTERA: CHRYSOPIDAE: CHRYSOPERLA).

Although traits of related species are likely to be similar due to common ancestry, mating signals are an exception. In singing insects, for example, song similarity has been documented only for allopatric or allochronic species pairs, and even then, not often. Where song similarity does occur, it has been logically attributed to the inheritance of ancestral traits rather than convergence.

THE ROLE OF COURTSHIP SONGS IN REPRODUCTIVE ISOLATION AMONG POPULATIONS OF GREEN LACEWINGS OF THE GENUS CHRYSOPERLA (NEUROPTERA: CHRYSOPIDAE).

Male and female lacewings tremulate during courtship, establishing duets that always precede copulation. Three distinct courtship songs are found in populations of the green lacewing Chrysoperla plorabunda (P1, P2 and P3 song morphs). Analysis of five features of the songs for individuals collected from Connecticut, Idaho, Oregon and California showed few differences within song morphs, but sympatric song morphs differed significantly in temporal features of the songs and their mode of presentation.