Improvement in glycemic excursions with a transcutaneous, real-time continuous glucose sensor: a randomized controlled trial.

Objective: Hypoglycemia and wide glucose excursions continue to be major obstacles to achieving target HbA(1c) values and the associated reductions in long-term complications (and economic costs) in people with insulin-treated diabetes. In this study we evaluated the accuracy, safety, and clinical effectiveness of a continuous glucose-sensing device.

Research Design And Methods: A total of 91 insulin-requiring patients with type 1 (n = 75) and type 2 (n = 16) diabetes were enrolled in this multicenter randomized study.

A variable residue in the pore of Kv1 channels is critical for the high affinity of blockers from sea anemones and scorpions.

Animal toxins are associated with well defined selectivity profiles; however the molecular basis for this property is not understood. To address this issue we refined our previous three-dimensional models of the complex between the sea anemone toxin BgK and the S5-S6 region of Kv1.1 (Gilquin, B.

Proopiomelanocortin neurons in nucleus tractus solitarius are activated by visceral afferents: regulation by cholecystokinin and opioids.

The nucleus tractus solitarius (NTS) receives dense terminations from cranial visceral afferents, including those from the gastrointestinal (GI) system. Although the NTS integrates peripheral satiety signals and relays this signal to central feeding centers, little is known about which NTS neurons are involved or what mechanisms are responsible. Proopiomelanocortin (POMC) neurons are good candidates for GI integration, because disruption of the POMC gene leads to severe obesity and hyperphagia.

Prediction of protein B-factor profiles.

The polypeptide backbones and side chains of proteins are constantly moving due to thermal motion and the kinetic energy of the atoms. The B-factors of protein crystal structures reflect the fluctuation of atoms about their average positions and provide important information about protein dynamics. Computational approaches to predict thermal motion are useful for analyzing the dynamic properties of proteins with unknown structures.

Assessing computational tools for the discovery of transcription factor binding sites.

The prediction of regulatory elements is a problem where computational methods offer great hope. Over the past few years, numerous tools have become available for this task. The purpose of the current assessment is twofold: to provide some guidance to users regarding the accuracy of currently available tools in various settings, and to provide a benchmark of data sets for assessing future tools.

Cranial afferent glutamate heterosynaptically modulates GABA release onto second-order neurons via distinctly segregated metabotropic glutamate receptors.

The balance between excitation and inhibition dictates central integration. Glutamatergic and GABAergic neurotransmission dominate this process. Cranial primary afferents enter the brainstem to release glutamate (Glu) onto second-order neurons within the caudal nucleus tractus solitarius (NTS) to initiate autonomic reflexes.

Structural dynamics of the M4 transmembrane segment during acetylcholine receptor gating.

The transition state structures that link the stable end states of allosteric proteins are largely unresolved. We used single-molecule kinetic analysis to probe the dynamics of the M4 transmembrane segments during the closed<==>open isomerization of the neuromuscular acetylcholine receptor ion channel (AChR). We measured the slopes (phi) of the free energy relationships for 87 mutants, which reveal the open- versus closed-like characters of the mutated residues at the transition state and hence the sequence and organization of gating molecular motions.

Strategies for cellular identification in nucleus tractus solitarius slices.

The indistinct regional anatomy and intermixing of second order neurons with projection and interneurons make cellular studies more difficult within the nucleus tractus solitarius (NTS). Here, we outline experimental strategies to join in vitro electrophysiological with neuroanatomical protocols to discriminate specific subpopulations of NTS neurons. Horizontally cutting the brain stem produces slices in which electrical activation of the solitary tract (ST) is free of local interneuron contamination.

Purinergic and vanilloid receptor activation releases glutamate from separate cranial afferent terminals in nucleus tractus solitarius.

Vanilloid (VR1) and purinergic (P2X) receptors are found in cranial afferent neurons in nodose ganglia and their central terminations within the solitary tract nucleus (NTS), but little is known about their function. We mechanically dissociated dorsomedial NTS neurons to preserve attached native synapses and tested for VR1 and P2X function primarily in spindle-shaped neurons resembling intact second-order neurons. All neurons (n = 95) exhibited spontaneous glutamate (EPSCs) and GABA (IPSCs)-mediated synaptic currents.

Gating dynamics of the acetylcholine receptor extracellular domain.

We used single-channel recording and model-based kinetic analyses to quantify the effects of mutations in the extracellular domain (ECD) of the alpha-subunit of mouse muscle-type acetylcholine receptors (AChRs). The crystal structure of an acetylcholine binding protein (AChBP) suggests that the ECD is comprised of a beta-sandwich core that is surrounded by loops. Here we focus on loops 2 and 7, which lie at the interface of the AChR extracellular and transmembrane domains.

Physiological and inflammatory response to instillation of an oxidized surfactant in a rat model of surfactant deficiency.

Pulmonary surfactant is a mixture of phospholipids ( approximately 90%) and surfactant-associated proteins (SPs) ( approximately 10%) that stabilize the lung by reducing the surface tension. One proposed mechanism by which surfactant is altered during acute lung injury is via direct oxidative damage to surfactant. In vitro studies have revealed that the surface activity of oxidized surfactant was impaired and that this effect could be overcome by adding SP-A.

The role of loop 5 in acetylcholine receptor channel gating.

Nicotinic acetylcholine receptor channel (AChR) gating is an organized sequence of molecular motions that couples a change in the affinity for ligands at the two transmitter binding sites with a change in the ionic conductance of the pore. Loop 5 (L5) is a nine-residue segment (mouse alpha-subunit 92-100) that links the beta4 and beta5 strands of the extracellular domain and that (in the alpha-subunit) contains binding segment A. Based on the structure of the acetylcholine binding protein, we speculate that in AChRs L5 projects from the transmitter binding site toward the membrane along a subunit interface.

Searching for statistically significant regulatory modules.

Motivation: The regulatory machinery controlling gene expression is complex, frequently requiring multiple, simultaneous DNA-protein interactions. The rate at which a gene is transcribed may depend upon the presence or absence of a collection of transcription factors bound to the DNA near the gene. Locating transcription factor binding sites in genomic DNA is difficult because the individual sites are small and tend to occur frequently by chance.

Synaptic and membrane properties of neurons in the dorsomedial hypothalamus.

Studies in intact rats have shown that the dorsomedial hypothalamus (DMH) plays a key role in generating stress-induced physiologic changes, including activation of the hypothalamic-pituitary-adrenal axis through direct projections to paraventricular hypothalamic nucleus (PVN). However, little is known about the cellular properties of DMH neurons. We employed whole-cell patch-clamp recording techniques to characterize membrane properties and spontaneous post-synaptic currents (PSCs) in DMH neurons, including those projecting to PVN (identified by prior injection of DiI into PVN), in rat hypothalamic slices.

High oxygen concentrations predispose mouse lungs to the deleterious effects of high stretch ventilation.

Mechanical ventilation is a necessary intervention for patients with acute lung injury. However, mechanical ventilation can propagate acute lung injury and increase systemic inflammation. The exposure to >21% oxygen is often associated with mechanical ventilation yet has not been examined within the context of lung stretch.

Ketamine differentially blocks sensory afferent synaptic transmission in medial nucleus tractus solitarius (mNTS).

Background: Ketamine increases blood pressure and heart rate by unknown mechanisms, but studies suggest that an intact central nervous system and arterial baroreceptors are required. In the brain stem, medial nucleus tractus solitarius receives afferents from nodose neurons that initiate cardiovascular autonomic reflexes. Here, the authors assessed ketamine actions on afferent medial nucleus tractus solitarius synaptic transmission.

Vanilloid-sensitive afferents activate neurons with prominent A-type potassium currents in nucleus tractus solitarius.

Cranial visceral afferents innervate second-order nucleus tractus solitarius (NTS) neurons via myelinated (A-type) and unmyelinated (C-type) axons in the solitary tract (ST). A- and C-type afferents often evoke reflexes with distinct performance differences, especially with regard to their frequency-dependent properties. In horizontal brainstem slices, we used the vanilloid receptor 1 agonist capsaicin (CAP; 100 nm) to identify CAP-sensitive and CAP-resistant ST afferent pathways to second-order NTS neurons and tested whether these two groups of neurons had similar intrinsic potassium currents.

Vanilloid receptors presynaptically modulate cranial visceral afferent synaptic transmission in nucleus tractus solitarius.

Although the central terminals of cranial visceral afferents express vanilloid receptor 1 (VR1), little is known about their functional properties at this first synapse within the nucleus tractus solitarius (NTS). Here, we examined whether VR1 modulates afferent synaptic transmission. In horizontal brainstem slices, solitary tract (ST) activation evoked EPSCs.

Estimating and evaluating the statistics of gapped local-alignment scores.

We present a novel maximum-likelihood-based algorithm for estimating the distribution of alignment scores from the scores of unrelated sequences in a database search. Using a new method for measuring the accuracy of p-values, we show that our maximum-likelihood-based algorithm is more accurate than existing regression-based and lookup table methods. We explore a more sophisticated way of modeling and estimating the score distributions (using a two-component mixture model and expectation maximization), but conclude that this does not improve significantly over simply ignoring scores with small E-values during estimation.