Epigenetic Regulation of Pancreas Development and Function.

The field of epigenetics broadly seeks to define heritable phenotypic modifications that occur within cells without changes to the underlying DNA sequence. These modifications allow for precise control and specificity of function between cell types-ultimately creating complex organ systems that all contain the same DNA but only have access to the genes and sequences necessary for their cell-type-specific functions. The pancreas is an organ that contains varied cellular compartments with functions ranging from highly regulated glucose-stimulated insulin secretion in the β-cell to the pancreatic ductal cells that form a tight epithelial lining for the delivery of digestive enzymes.

The SSBP3 co-regulator is required for glucose homeostasis, pancreatic islet architecture, and beta-cell identity.

Objective: Transcriptional complex activity drives the development and function of pancreatic islet cells to allow for proper glucose regulation. Prior studies from our lab and others highlighted that the LIM-homeodomain transcription factor (TF), Islet-1 (Isl1), and its interacting co-regulator, Ldb1, are vital effectors of developing and adult β-cells. We further found that a member of the Single Stranded DNA-Binding Protein (SSBP) co-regulator family, SSBP3, interacts with Isl1 and Ldb1 in β-cells and primary islets (mouse and human) to impact β-cell target genes MafA and Glp1R in vitro.

The Ldb1 transcriptional co-regulator is required for establishment and maintenance of the pancreatic endocrine lineage.

Pancreatic islet cell development is regulated by transcription factors (TFs) that mediate embryonic progenitor differentiation toward mature endocrine cells. Prior studies from our lab and others showed that the islet-enriched TF, Islet-1 (Isl1), interacts with the broadly-expressed transcriptional co-regulator, Ldb1, to regulate islet cell maturation and postnhyperatal function (by embryonic day (E)18.5).

Partners in Crime: Beta-Cells and Autoimmune Responses Complicit in Type 1 Diabetes Pathogenesis.

Type 1 diabetes (T1D) is an autoimmune disease characterized by autoreactive T cell-mediated destruction of insulin-producing pancreatic beta-cells. Loss of beta-cells leads to insulin insufficiency and hyperglycemia, with patients eventually requiring lifelong insulin therapy to maintain normal glycemic control. Since T1D has been historically defined as a disease of immune system dysregulation, there has been little focus on the state and response of beta-cells and how they may also contribute to their own demise.

LIM-domain transcription complexes interact with ring-finger ubiquitin ligases and thereby impact islet β-cell function.

Diabetes is characterized by a loss of β-cell mass, and a greater understanding of the transcriptional mechanisms governing β-cell function is required for future therapies. Previously, we reported that a complex of the Islet-1 (Isl1) transcription factor and the co-regulator single-stranded DNA-binding protein 3 (SSBP3) regulates the genes necessary for β-cell function, but few proteins are known to interact with this complex in β-cells. To identify additional components, here we performed SSBP3 reverse-cross-linked immunoprecipitation (ReCLIP)- and MS-based experiments with mouse β-cell extracts and compared the results with those from our previous Isl1 ReCLIP study.

Acute hemodynamic and long-term clinical effects of isradipine in patients with coronary artery disease and chronic heart failure. A double-blind, placebo-controlled study.

To assess the acute hemodynamic and long-term clinical effects of isradipine, a calcium antagonist of the dihydropyridine class, we performed a double-blind, placebo-controlled parallel study in 19 patients with coronary artery disease (CAD) and stable chronic heart failure (CHF). Their mean age was 56 +/- 5 years, and left ventricular ejection fraction (LVEF) was 0.18 +/- 0.

Effects of isradipine on hemodynamic parameters and ventricular tachycardia in healed myocardial infarction.

The calcium-entry blocker isradipine was tested in a closed-chest pig model for chronic myocardial infarction. Ischemia was evoked in anesthetized pigs (25-35 kg) by inflating a catheter balloon in the left anterior descending coronary artery for at least 45 min. Hemodynamic monitoring and signal averaging of X, Y, and Z electrocardiographic leads were performed (150 beats, filtered at 50 Hz).

Patency of arm vein grafts used in aorto-coronary bypass surgery.

Arm veins have been used in myocardial revascularisation procedures as a last resort bypass conduit because of their associated low patency. Nevertheless, leg veins and mammary arteries, which are the most commonly used, are sometimes not sufficient, leaving little choice as to the bypass conduit. To assess the properties of arm veins in bypass surgery, we compared a group of 28 patients that underwent an arm vein graft coronary bypass procedure with a matched group of patients in which leg veins were used.

Cardiac electrophysiologic properties of intravenous isradipine in patients with sick sinus syndrome.

Isradipine is a new dihydrophyridine calcium antagonist with powerful vasodilating properties. Although therapeutic concentrations do not affect myocardial contractility in vivo, in vitro studies have demonstrated a negative chronotropic action with only minor dromotropic influence. In humans with normal sinus and atrioventricular node function, even in the presence of beta-blockade, such a negative chronotropic effect could not be proved.

Isolation and characterization of acetylcholine receptor membrane-associated (nonreceptor v2-protein) and soluble electrocyte creatine kinases.

Creatine kinase has been identified as a most prominent component of Torpedo electric organ and a minority constituent of the acetylcholine receptor (AChR) membranes obtained therefrom. Purification by low temperature ethanol extraction, precipitation of the Mg2+-enzyme complex, and mercurial-agarose chromatography yield preparations of soluble kinase with specific activities greater than 550 units/mg protein. Retention times in ion-exchange high performance liquid chromatography, electrophoretic behavior, immunochemical properties, tryptic mapping, and amino acid composition enable the comparison of creatine kinase isoenzymes.

Cation-exchange, high-performance liquid chromatographic determination of hemoglobin A1c.

We describe a rapid, simple, and sensitive high-performance liquid chromatographic method for the determination of hemoglobin A1c with a bonded-phase cation-exchange column. About five measurements are obtained per hour on small quantities of whole blood. Sample preparation requires no centrifugation or washing of cells.

Separation and measurement of isoenzymes and other proteins by high-performance liquid chromatography.

We review the state-of-the-art of the separation of isoenzymes and other proteins by high-performance liquid chromatography (HPLC) and their subsequent, continuous detection and activity assay by post-column reaction (PCR). We describe the developments leading to current practice. These developments are categorized by column packings, post-column reaction detectors and applications in which specific analysis systems for isoenzymes, especially for lactate dehydrogenase (LD) and creatine kinase (CK) are discussed.

Interferences appearing in fluorometrically measured liquid-chromatographic profiles of creatine kinase isoenzymes in serum.

We observed nonenzymic peaks when serum isoenzymes of lactate dehydrogenase (EC 1.1.1.

New developments in analysis of isoenzymes separated by "high-performance" liquid chromatography.

We have developed two enzyme analyzers for use in "high-performance" liquid chromatography. In both systems two detectors are used, placed after the column effluent has been combined with assay reagent. In one system, an absorbance detector is placed before and after a post-column reaction coil.

Dual-detector-post-column reactor system for the detection of isoenzymes separated by high-performance liquid chromatography. II. Evaluation and application to lactate dehydrogenase isoenzymes.

We describe the separation of lactate dehydrogenase isoenzymes by high-performance liquid chromatography-anion-exchange columns and their quantitation by a computer-controlled, dual-detector post-column reaction system. The recoveries from the separation column were ca. 90%.

Dual-detector-post-column reactor system for the detection of isoenzymes separated by high-performance liquid chromatography. I. Description and theory.

We describe a dual-detector-post-column chromatographic reaction detector system that corrects for substances present in biological samples that interfere with the measurement of isoenzymes separated on a chromatographic column. The response observed at the detector in front of the reaction coil is mathematically dispersed, time transformed and subtracted from the detector behind the coil to produce a blank corrected chromatogram. The same computer program calculates peak areas and other chromatographic parameters such as height equivalent to a theoretical plate and retention time.

Statistical analysis of method comparison data. Testing normality.

A Lilliefors test of normality has been applied to data from precision and accuracy studies. Most data sets tested as non-normal. Simulation studies showed that the test is extremely sensitive to the rounded, narrowly distributed data that are typical of method performance studies in clinical chemistry.

Computer-controlled instrument system for sequential chemical testing III. Application to liver assessment.

We used the previously described [Clin. Chem. 19, 1114 (1973)] and evaluated [Clin.

Enzyme-selective detector systems for high-pressure liquid chromatography.

This paper describes the performance of absorbance and fluorescence detectors in two configurations of post-column reactors for selectively detecting and quantitating isonenzymes eluted form a high-pressure liquid chromatography column. Superb resolution of the isoenzymes of lactic dehydrogenase is illustrated by the use of new ion-exchange materials.

High-pressure liquid-chromatographic separation of lactate dehydrogenase isoenzymes.

The isoenzymes of lactate dehydrogenase (EC 1.1.1.

Automated separation and measurement of lactate dehydrogenase isoenzymes.

We describe a totally automated, computer-controlled system for separating and measuring the activity of lactate dehydrogenase (EC 1.1.1.

Computer-assisted differential diagnosis of laboratory abnormalities and follow-up testing. Evaluation of the accuracy of a computer program.

An evaluation is made of a computer program which generates a differential diagnostic list given a set of input data obtained from an admission chemistry screening profile. The program is tested by supplying input data on patients for whom diseases are known. The laboratory data from 367 patients are examined.

Trend detection in control data: optimization and interpretation of Trigg's technique for trend analysis.

A method for trend detection, Trigg's technique [Oper. Res. Q.

A versatile temperature-controlled reaction cuvet.

A thermostatted reaction cuvet, operating under computerized or manual temperature control in the ultraviolet or visible region, is described and evaluated. The cell was designed for use with the automated chemistry system described earlier [Clin. Chem.