Free fatty acid-induced peripheral insulin resistance augments splanchnic glucose uptake in healthy humans

To investigate the effect of elevated plasma free fatty acid (FFA) concentrations on splanchnic glucose uptake (SGU), we measured SGU in nine healthy subjects (age, 44 +/- 4 yr; body mass index, 27.4 +/- 1.2 kg/m(2); fasting plasma glucose, 5.2 +/- 0.1 mmol/l) during an Intralipid-heparin (LIP) infusion and during a saline (Sal) infusion. SGU was estimated by the oral glucose load (OGL)-insulin clamp method: subjects received a 7-h euglycemic insulin (100 mU x m(-2) x min(-1)) clamp, and a 75-g OGL was ingested 3 h after the insulin clamp was started. After glucose ingestion, the steady-state glucose infusion rate (GIR) during the insulin clamp was decreased to maintain euglycemia. SGU was calculated by subtracting the integrated decrease in GIR during the period after glucose ingestion from the ingested glucose load. [3-(3)H]glucose was infused during the initial 3 h of the insulin clamp to determine rates of endogenous glucose production (EGP) and glucose disappearance (R(d)). During the 3-h euglycemic insulin clamp before glucose ingestion, R(d) was decreased (8.8 +/- 0.5 vs. 7.6 +/- 0.5 mg x kg(-1) x min(-1), P < 0.01), and suppression of EGP was impaired (0.2 +/- 0.04 vs. 0.07 +/- 0.03 mg x kg(-1) x min(-1), P < 0.01). During the 4-h period after glucose ingestion, SGU was significantly increased during the LIP vs. Sal infusion study (30 +/- 2 vs. 20 +/- 2%, P < 0.005). In conclusion, an elevation in plasma FFA concentration impairs whole body glucose R(d) and insulin-mediated suppression of EGP in healthy subjects but augments SGU.     

Applications of a bilateral denoising filter in biological electron microscopy

Due to the sensitivity of biological sample to the radiation damage, the low dose imaging conditions used for electron microscopy result in extremely noisy images. The processes of digitization, image alignment, and 3D reconstruction also introduce additional sources of noise in the final 3D structure. In this paper, we investigate the effectiveness of a bilateral denoising filter in various biological electron microscopy applications. In contrast to the conventional low pass filters, which inevitably smooth out both noise and structural features simultaneously, we found that bilateral filter holds a distinct advantage in being capable of effectively suppressing noise without blurring the high resolution details. In as much, we have applied this technique to individual micrographs, entire 3D reconstructions, segmented proteins, and tomographic reconstructions.     

Design,synthesis, and structure-activity relationship of a new class of amidinophenylurea-based factor VIIa inhibitors

Selective inhibition of coagulation factor VIIa has recently gained attraction as interesting approach towards antithrombotic treatment. Using parallel synthesis supported by structure-based design and X-ray crystallography, we were able to identify a novel series of amidinophenylurea derivatives with remarkable affinity for factor VIIa. The most potent compound displays a K(i) value of 23 nM for factor VIIa.     

QSAR study on solubility of alkanes in water and their partition coefficients in different solvent systems using PI index

The aqueous solubility (S(w)) of liquids and solids, expressed as log S(w) as well as their partition coefficients in different solvent systems viz. P(oct) (partition coefficient in octanol-water), P(16) (partition coefficient in water-hexadecane), P(alk) (partition coefficient in water-alkane), and P(cyc) (partition coefficient in water-cyclohexane), and aqueous solubility (S(w)) have been estimated using the PI (Padmakar-Ivan) index and the results compared with those obtained using the widely used Wiener index (W). Regression analysis of the data using n-alkanes show that the PI index gives better results than the W index.     

I n Vivo Evaluation of 5-ASA Colon-Specific Tablets Using Experimental-Induced Colitis Rat Animal Model

Colonic drug delivery is intended not only for local treatment in inflammatory bowel disease (IBD) but also for systemic delivery of therapeutics. Intestinal myeloperoxidase (MPO) determination could be used to estimate the average level of inflammation in colon as well as to determine the efficacy of drugs to be used in the treatment of inflammatory bowel diseases or study the specificity of dosage forms to be used for colonic targeting of anti-inflammatory drugs. Colonic prodrug sulfasalazine (SASP) gets metabolized to give 5-aminosalicylic acid (5-ASA), which is the active portion of SASP. However, when given orally, 5-ASA is absorbed in upper part of gastrointestinal tract (GIT) and not made available in colon. In the present study, colon-targeted delivery of 5-ASA was achieved by formulating tablets with two natural polymers namely guar gum and pectin using compression coating method. Colonic specificity of 5-ASA tablets (prepared using guar gum and pectin as polymers) was evaluated in vitro using simulated fluids mimicking in vivo environment as well as in vivo method using chemically (2,4,6-trinitrobenzenesulfonic acid and acetic acid)-induced colitis rat model. Both colon-specific formulations of 5-ASA (guar gum and pectin) were observed to be more effective in reducing inflammation in chemically induced colitis rat models when compared to colon-specific prodrug sulfasalazine as well as conventional 5-ASA administered orally.KEY WORDS: colitis, colon-specific drug delivery, myeloperoxidase     

Understanding Voltage Gating of Providencia stuartii Porins at Atomic Level

Bacterial porins are water-filled β-barrel channels that allow translocation of solutes across the outer membrane. They feature a constriction zone, contributed by the plunging of extracellular loop 3 (L3) into the channel lumen. Porins are generally in the open state, but undergo gating in response to external voltages. To date the underlying mechanism is unclear. Here we report results from molecular dynamics simulations on the two porins of Providenica stuartii, Omp-Pst1 and Omp-Pst2, which display distinct voltage sensitivities. Voltage gating was observed in Omp-Pst2, where the binding of cations in-between L3 and the barrel wall results in exposing a conserved aromatic residue in the channel lumen, thereby halting ion permeation. Comparison of Omp-Pst1 and Omp-Pst2 structures and trajectories suggests that their sensitivity to voltage is encoded in the hydrogen-bonding network anchoring L3 onto the barrel wall, as we observed that it is the strength of this network that governs the probability of cations binding behind L3. That Omp-Pst2 gating is observed only when ions flow against the electrostatic potential gradient of the channel furthermore suggests a possible role for this porin in the regulation of charge distribution across the outer membrane and bacterial homeostasis.     

Direct Mouse Trauma/Burn Model of Heterotopic Ossification

Heterotopic ossification (HO) is the formation of bone outside of the skeleton which forms following major trauma, burn injuries, and orthopaedic surgical procedures. The majority of animal models used to study HO rely on the application of exogenous substances, such as bone morphogenetic protein (BMP), exogenous cell constructs, or genetic mutations in BMP signaling. While these models are useful they do not accurately reproduce the inflammatory states that cause the majority of cases of HO. Here we describe a burn/tenotomy model in mice that reliably produces focused HO. This protocol involves creating a 30% total body surface area partial thickness contact burn on the dorsal skin as well as division of the Achilles tendon at its midpoint. Relying solely on traumatic injury to induce HO at a predictable location allows for time-course study of endochondral heterotopic bone formation from intrinsic physiologic processes and environment only. This method could prove instrumental in understanding the inflammatory and osteogenic pathways involved in trauma-induced HO. Furthermore, because HO develops in a predictable location and time-course in this model, it allows for research to improve early imaging strategies and treatment modalities to prevent HO formation.     

Strategies for Self-organization: Learning from a Village-level Community-based Conservation Initiative in India

Self-organization is a key condition to the success of community-based conservation initiatives, including those recognized by the Equator Initiative of the UNDP. This paper contributes to emerging scholarship that focuses on community-based conservation in South Asia and in particular examines self-organization strategies within a small-scale community-based conservation initiative in a cross-cultural setting to further understanding about how such initiatives originate, sustain and grow. This is achieved through a case study of the Baripada Forest Protection Initiative in India by utilizing in-depth interviews and focus groups. In addition to certain often-cited strategies for self-organization, the Baripada initiative included unique features of self-organization such as village community design, implementation and adaptation of rules for local natural resources use and conservation, little need for financial support, and significant mobilization of human resources. These strategies, along with emerging social learning opportunities (e.g., a community plant diversity register) inspired by the Baripada initiative, inform and enrich the criteria for designing and evaluating conservation and development initiatives, irrespective of their scale.     

A systematic investigation of multiheme c-type cytochromes in prokaryotes

Multiheme c-type cytochromes (MHCs) are metalloproteins that can play various biochemical roles, including enzymatic activity and electron transfer. As electron transfer proteins, the presence of multiple heme cofactors in the vicinity allows electrons to rapidly travel relatively long distances. MHCs are often characterized by relatively low structural complexity, with the heme cofactors being largely responsible for maintaining the structure in place, owing to the protein–heme covalent linkages. In this work, we analyzed an extensive ensemble of 594 complete prokaryotic proteomes, amounting to more than 1.9 million sequences, to characterize their content in MHCs. We identified 1,659 MHCs in 258 organisms. The presence of MHCs was found to correlate quite well with the capability of an organism to synthesize or take up heme. For two organisms, the presence of MHCs in the proteome could be taken as a hint to the presence of divergent heme uptake pathways. The most common numbers of heme-binding motifs in a sequence were four (25%) and two (23%), followed by five (13%) and ten (9.8%). The average protein-to-heme ratio was relatively similar for all MHCs, except diheme proteins, regardless of the number of motifs at around 60 ± 30. The latter ratio could in favorable cases be a useful indicator for functional assignments of novel MHCs. Finally, we showed that the amount of structural information currently available for MHCs is limited with respect to the diversity of this broad class of metalloproteins. Experimental efforts in the structural investigation of MHCs are thus warranted.