Background The optimal target range for blood glucose in critically ill patients remains unclear. Methods Within 24 hours after admission to an intensive care unit(ICU), adults who were expected to require treatment in the ICU on 3 or more consecutive days were randomly assigned to undergo either intensive glucose control, with a target blood glucose range of 81 to 108 mg per deciliter(4.5 to 6.0 mmol per liter), or conventional glucose control, with a target of 180 mg or less per deciliter(10.0 mmol or less per liter). We defined the primary end point as death from any cause within 90 days after randomization. Results Of the 6104 patients who underwent randomization, 3054 were assigned to undergo intensive control and 3050 to undergo conventional control; data with regard to the primary outcome at day 90 were available for 3010 and 3012 patients, respectively. The two groups had similar characteristics at baseline. A total of 829 patients(27.5%) in the intensive-control group and 751(24.9%) in the conventional-control group died(odds ratio for intensive control, 1.14; 95% confidence interval, 1.02 to 1.28; P=0.02). The treatment effect did not differ significantly between operative(surgical) patients and nonoperative(medical) patients(odds ratio for death in the intensive-control group, 1.31 and 1.07, respectively; P = 0.10). Severe hypoglycemia(blood glucose level, <40 mg per deciliter>[2.2 mmol per liter]) was reported in 206 of 3016 patients(6.8%) in the intensive-control group and 15 of 3014(0.5%) in the conventional-control group(P<0.001). There was no significant difference between the two treatment groups in the median number of days in the ICU(P = 0.84) or hospital(P = 0.86) or the median number of days of mechanical ventilation(P = 0.56) or renal-replacement therapy(P=0.39). Conclusions In this large, international, randomized trial, we found that intensive glucose control increased mortality among adults in the ICU: a blood glucose target of 180 mg or less per deciliter resulted in lower mortality than did a target of 81 to 108 mg per deciliter.(ClinicalTrials.gov number, NCT00220987.)

Sec1p/Munc18 (SM) proteins are believed to play an integral role in vesicle transport through their interaction with SNAREs. Different SM proteins have been shown to interact with SNAREs via different mechanisms, leading to the conclusion that their function has diverged. To further explore this notion, in this study, we have examined the molecular interactions between Munc18c and its cognate SNAREs as these molecules are ubiquitously expressed in mammals and likely regulate a universal plasma membrane trafficking step. Thus, Munc18c binds to monomeric syntaxin4 and the N-terminal 29 amino acids of syntaxin4 are necessary for this interaction. We identified key residues in Munc18c and syntaxin4 that determine the N-terminal interaction and that are consistent with the N-terminal binding mode of yeast proteins Sly1p and Sed5p. In addition, Munc18c binds to the syntaxin4/SNAP23/ VAMP2 SNARE complex. Pre-assembly of the syntaxin4/ Munc18c dimer accelerates the formation of SNARE complex compared to assembly with syntaxin4 alone. These data suggest that Munc18c interacts with its cognate SNAREs in a manner that resembles the yeast proteins Sly1p and Sed5p rather than the mammalian neuronal proteins Munc18a and syntaxin1a. The Munc18c-SNARE interactions described here imply that Munc18c could play a positive regulatory role in SNARE assembly.

The insulin-stimulated trafficking of GLUT4 to the plasma membrane in muscle and fat tissue constitutes a central process in blood glucose homeostasis. The tethering, docking, and fusion of GLUT4 vesicles with the plasma membrane (PM) represent the most distal steps in this pathway and have been recently shown to be key targets of insulin action. However, it remains unclear how insulin influences these processes to promote the insertion of the glucose transporter into the PM. In this study we have identified a previously uncharacterized role for cortical actin in the distal trafficking of GLUT4. Using high-frequency total internal reflection fluorescence microscopy (TIRFM) imaging, we show that insulin increases actin polymerization near the PM and that disruption of this process inhibited GLUT4 exocytosis. Using TIRFM in combination with probes that could distinguish between vesicle transport and fusion, we found that defective actin remodeling was accompanied by normal insulin-regulated accumulation of GLUT4 vesicles close to the PM, but the final exocytotic fusion step was impaired. These data clearly resolve multiple steps of the final stages of GLUT4 trafficking, demonstrating a crucial role for actin in the final stage of this process.

Accreditation is emerging as a preferred framework for building quality medical laboratory systems in resource-limited settings. Despite the low numbers of laboratories accredited to date, accreditation has the potential to improve the quality of health care for patients through the reduction of testing errors and attendant decreases in inappropriate treatment. Accredited laboratories can become more accountable and less dependent on external support. Efforts made to achieve accreditation may also lead to improvements in the management of laboratory networks by focusing attention on areas of greatest need and accelerating improvement in areas such as supply chain, training, and instrument maintenance. Laboratory accreditation may also have a positive influence on performance in other areas of health care systems by allowing laboratories to demonstrate high standards of service delivery. Accreditation may, thus, provide an effective mechanism for health system improvement yielding long-term benefits in the quality, cost-effectiveness, and sustainability of public health programs. Further studies are needed to strengthen the evidence on the benefits of accreditation and to justify the resources needed to implement accreditation programs aimed at improving the performance of laboratory systems.

The distribution of P2X receptors on neurons in rat superior cervical ganglia and lability of P2X receptors on exposure to agonists were determined. Antibody labeling of each P2X subtype P2X 1 -P2X 7 showed neurons isolated into culture possessed primarily P2X 2 subunits with others occurring in order P2X 7 > P2X 6 > P2X 3 > P2X 1 > P2X 5 > P2X 4 . Application of ATP and ␣,␤؊meATP to neurons showed they possessed a predominantly nondesensitizing P2X receptor type insensitive to ␣,␤؊ meATP, consistent with immunohistochemical observations. P2X 1 -green fluorescent protein (GFP) was used to study the time course of P2X 1 receptor clustering in plasma membranes of neurons and internalization of receptors following prolonged exposure to ATP. At 12-24 h after adenoviral infection, P2X 1 -GFP formed clusters about 1 m diameter in the neuron membrane. Application of ATP and ␣,␤؊meATP showed these neurons possessed a predominantly desensitizing P2X receptor type sensitive to ␣,␤؊meATP. Infection converted the major functional P2X receptor type in the membrane to P2X 1 . Exposure of infected neurons to ␣,␤؊meATP for less than 60 s led to the disappearance of P2X 1 -GFP fluorescence from the cell surface that was blocked by monensin, indicating the chimera is normally endocytosed into these organelles on exposure to agonist.P2X-type purinergic receptors consist of seven subtypes, classified as P2X 1 to P2X 7 , which form ligand-gated cation channels that contain cytoplasmic N and C termini and a large extracellular domain separating the two transmembrane segments (1). Antibodies against peptides from the C-terminal portion of the P2X 1 subtype have been used to determine the distribution of P2X 1 receptors in the vas deferens and urinary bladder, where they are found on the smooth muscle cells (2). Recently it has been shown that different P2X receptor subtypes form clusters of two different sizes on the smooth muscle cells of the rat urinary bladder, vas deferens, and blood vessels: large numbers of small clusters of about 0.4-m diameter distributed over the smooth muscle and small numbers of large clusters greater than 1-m diameter positioned under junctional varicosities (3-5). The large junctional P2X clusters can be observed during normal development to be formed from small clusters of a number of different subtypes, which gather in large numbers in the vicinity of the nerve varicosities (6). Sympathetic ganglion cells were reported to possess P2X receptors, primarily of the P2X 2 , P2X 4 , and P2X 6 subtypes (7), and transcripts for P2X 1 , P2X 2 , P2X 4 , and P2X 6 are present (8), although it is not known whether these receptors are organized into large and small clusters and if so whether the large clusters are found beneath boutons as expected if they mediate some aspect of transmission. In the present work, both large and small clusters of different P2X subunit types are shown to exist on ganglion cells, and their spatial disposition with respect to preganglionic boutons has been ascertained.The existence of P2...