Implications of Pleural Fluid Composition in Persistent Pleural Effusion following Orthotopic Liver Transplant.

Persistent pleural effusions (PPEf) represent a known complication of orthotopic liver transplant (OLT). However, their clinical relevance is not well described. We evaluated the clinical, biochemical, and cellular characteristics of post-OLT PPEf and assessed their relationship with longitudinal outcomes. We performed a retrospective cohort study of OLT recipients between 2006 and 2015. Included patients had post-OLT PPEf, defined by effusion persisting >30 days after OLT and available pleural fluid analysis. PPEf were classified as transudates or exudates (ExudLight) by Light's criteria. Exudates were subclassified as those with elevated lactate dehydrogenase (ExudLDH) or elevated protein (ExudProt). Cellular composition was classified as neutrophil- or lymphocyte-predominant. Of 1602 OLT patients, 124 (7.7%) had PPEf, of which 90.2% were ExudLight. Compared to all OLT recipients, PPEf patients had lower two-year survival (HR 1.63; p = 0.002). Among PPEf patients, one-year mortality was associated with pleural fluid RBC count (p = 0.03). While ExudLight and ExudProt showed no association with outcomes, ExudLDH were associated with increased ventilator dependence (p = 0.03) and postoperative length of stay (p = 0.03). Neutrophil-predominant effusions were associated with increased postoperative ventilator dependence (p = 0.03), vasopressor dependence (p = 0.02), and surgical pleural intervention (p = 0.02). In summary, post-OLT PPEf were associated with increased mortality. Ninety percent of these effusions were exudates by Light's criteria. Defining exudates using LDH only and incorporating cellular analysis, including neutrophils and RBCs, was useful in predicting morbidity.

Chest tube output, duration, and length of stay are similar for pneumothorax and hemothorax seen only on computed tomography vs. chest radiograph.

PURPOSE: Whole-body computed tomography (CT) for blunt trauma patients is common. Chest CT (CCT) identifies "occult" pneumo- (PTX) and hemothorax (HTX) not seen on chest radiograph (CXR), one-third of whom get chest tubes, while CXR identifies "non-occult" PTX/HTX. To assess chest tube value for occult injury vs. expectant management, we compared output, duration, and length of stay (LOS) for chest tubes placed for occult vs. non-occult (CXR-visible) injury. METHODS: We compared chest tube output and duration, and patient length of stay for occult vs. non-occult PTX/HTX. This was a retrospective analysis of 5451 consecutive Level I blunt trauma patients, from 2010 to 2013. RESULTS: Of these blunt trauma patients, 402 patients (7.4%) had PTX, HTX or both, and both CXR and CCT. One third (n = 136, 33.8%) had chest tubes placed in 163 hemithoraces (27 bilateral). Non-occult chest tube output for all patients was 1558 ± 1919 cc (n = 54), similar to occult at 1123 ± 1076 cc (n = 109, p = 0.126). Outputs were similar for HTX-only patients, with non-occult (n = 34) at 1917 ± 2130 cc, vs. occult (n = 54) at 1449 ± 1131 cc (p = 0.24). Chest tube duration for all patients was 6.3 ± 4.9 days for non-occult vs. 5.0 ± 3.3 for occult (p = 0.096). LOS was similar between all occult injury patients (n = 46) and non-occult (n = 90, 17.0 ± 15.8 vs. 13.7 ± 11.9 days, p = 0.23). CONCLUSION: Mature clinical judgment may dictate which patients need chest tubes and explain the similarity between groups.

Length-Selective Synthesis of Acylglycerol-Phosphates through Energy-Dissipative Cycling.

The main aim of origins of life research is to find a plausible sequence of transitions from prebiotic chemistry to nascent biology. In this context, understanding how and when phospholipid membranes appeared on early Earth is critical to elucidating the prebiotic pathways that led to the emergence of primitive cells. Here we show that exposing glycerol-2-phosphate to acylating agents leads to the formation of a library of acylglycerol-phosphates. Medium-chain acylglycerol-phosphates were found to self-assemble into vesicles stable across a wide range of conditions and capable of retaining mono- and oligonucleotides. Starting with a mixture of activated carboxylic acids of different lengths, iterative cycling of acylation and hydrolysis steps allowed for the selection of longer-chain acylglycerol-phosphates. Our results suggest that a selection pathway based on energy-dissipative cycling could have driven the selective synthesis of phospholipids on early Earth.

Common origins of RNA, protein and lipid precursors in a cyanosulfidic protometabolism.

A minimal cell can be thought of as comprising informational, compartment-forming and metabolic subsystems. To imagine the abiotic assembly of such an overall system, however, places great demands on hypothetical prebiotic chemistry. The perceived differences and incompatibilities between these subsystems have led to the widely held assumption that one or other subsystem must have preceded the others. Here we experimentally investigate the validity of this assumption by examining the assembly of various biomolecular building blocks from prebiotically plausible intermediates and one-carbon feedstock molecules. We show that precursors of ribonucleotides, amino acids and lipids can all be derived by the reductive homologation of hydrogen cyanide and some of its derivatives, and thus that all the cellular subsystems could have arisen simultaneously through common chemistry. The key reaction steps are driven by ultraviolet light, use hydrogen sulfide as the reductant and can be accelerated by Cu(I)-Cu(II) photoredox cycling.

Total synthesis of resorcinol amide Hsp90 inhibitor AT13387.

The synthesis of C-5-substituted resorcinol amide AT13387, a known Hsp90 inhibitor currently in clinical trials, is reported without the use of phenolic protection in an overall yield of 13.4%. Biomimetic aromatization and Suzuki-Miyaura cross coupling approach were employed to synthesize the resorcinol and iso-indoline units, respectively, which were efficiently coupled using Grignard-mediated amidation.

Synthesis of 6-substituted-4-hydroxy-2-pyridinones via intramolecular ketene trapping of functionalized enamine-dioxinones.

The synthesis of various 6-substituted-4-hydroxy-2-pyridinones is reported. The functionalized keto-dioxinones were constructed via a diethylzinc mediated crossed Claisen condensation reaction and subsequent enamine formation, thermolysis, and cyclization-aromatization providing the pyridinone unit.

Conversion of α-amino acids into bioactive o-aminoalkyl resorcylates and related dihydroxyisoindolinones.

The synthesis of biologically active o-aminoalkyl resorcylates and related dihydroxyisoindolinones from functionalized α-amino acids without the use of phenolic protection is described. The key aminoalkyl-diketo-dioxinone intermediates were prepared utilizing a crossed Claisen condensation reaction in the presence of diethylzinc. The aromatic unit was constructed via late stage cyclization and aromatization, and subsequent modification provided the novel resorcylates which showed activity against a selection of receptors and kinases, including 5-HT and CDK.

Comparing experimental and computational alanine scanning techniques for probing a prototypical protein-protein interaction.

The central role of protein-protein interactions in a wide range of cellular processes makes them a target for research and drug discovery. A variety of methods, both experimental and theoretical, exist for probing protein interfaces for residues that affect activity and binding affinity. Using as an example a protein-protein complex between trypsin and a nine-residue synthetic peptide, we experimentally assay-binding affinities for a variety of mutants and determine their relative free energy of binding, ΔΔG, to rank the importance of interface residues to binding. We then compare how accurately, precisely and reliably computational methods for calculating ΔΔG can replicate these results. We find that a 'post-process alanine scanning' protocol of a single native complex trajectory gives results with better accuracy than running separate molecular dynamics (MD) trajectories for individual mutants. Compared across 10 independent simulations, we find that results from the post-process alanine scanning are also more precise and are obtained over five times faster than their equivalent with the 'full MD' protocol. These results suggest that, although not suitable in every case, post-process alanine scanning is a useful and reliable tool in predicting important residues at protein interfaces with potential for modulation.

Estimation of pitavastatin calcium in tablet dosage forms by column liquid chromatography and ultraviolet spectrophotometry.

Two simple and accurate methods for the determination of pitavastatin calcium (PIT) in tablet dosage forms were developed and validated using column liquid chromatography (LC) and UV spectrophotometry. The LC separation was achieved on a Phenomenex Luna C18 column (250 mm, 4.6 mm id, 5 microm) in the isocratic mode using acetonitrile-water-triethylamine (80 + 19.8 + 0.2, v/v/v), adjusted to pH 3.5 +/- 0.05 with orthophosphoric acid, as the mobile phase at a flow rate of 1.5 mL/min. The retention time was 5.70 min. Both the methods were performed at 238 nm, the wavelength of maximum absorbance of PIT in methanol. In the LC method, quantification was achieved with a photodiode array detector over the concentration range of 0.1-2.5 microg/mL with a mean recovery of 100.26 +/- 0.75%. In the UV method, quantification was achieved over the concentration range of 2-20 microg/mL with mean recovery of 99.65 +/- 1.24%. Both methods were validated, and the results were compared statistically. They were found to be simple, specific, accurate, and precise. The methods were successfully applied for the determination of PIT in tablet dosage form without any interference from common excipients.

HPTLC determination of rabeprazole and domperidone in capsules and its validation.

This paper describes a validated high-performance thin-layer chromatography (HPTLC) method for simultaneous estimation of rabeprazole (RA) and domperidone (DO) in pure powder and in capsule formulations. An HPTLC method separation is achieved on an aluminum sheet of silica gel 60F(254) using ethyl acetate-methanol-benzene-acetonitrile (30:20:30:20 v/v) as mobile phase. Quantitation is achieved with UV detection at 287 nm over a concentration range of 400-1200 ng/spot and 600-1800 ng/spot with mean recovery of 99.82 +/- 0.74 and 99.43 +/- 0.68 for RA and DO, respectively, in the HPTLC method. This method is simple, precise, and sensitive, and it is applicable for the simultaneous determination of RA and DO in pure powder and in capsule formulation.

High-performance liquid chromatography and thin-layer chromatography for the simultaneous quantitation of rabeprazole and mosapride in pharmaceutical products.

Simple, sensitive high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) methods are developed for the quantitative estimation of rabeprazole and mosapride in their combined pharmaceutical dosage forms. In HPLC, rabeprazole and mosapride are chromatographed using 0.01M 6.5 pH ammonium acetate buffer-methanol-acetonitrile (40:20:40, v/v, pH 5.70+/-0.02) as the mobile phase at a flow rate of 1.0 mL/min. In TLC, the mobile phase is ethyl acetate-methanol-benzene (2:0.5:2.5, v/v). Both the drugs are scanned at 276 nm. The retention times of rabeprazole and mosapride are found to be 4.93+/-0.01 and 9.79+/-0.02, respectively. The Rf values of rabeprazole and mosapride are found to be 0.42+/-0.02 and 0.61+/-0.02, respectively. The linearities of rabeprazole and mosapride are in the range of 400-2000 ng/mL and 300-1500 ng/mL, respectively, for HPLC; in TLC, the linearities of rabeprazole and mosapride are in the range of 400-1200 ng/spot and 300-900 ng/spot, respectively. The limit of detection is found to be 97.7 ng/mL for rabeprazole and 97.6 ng/mL for mosapride in HPLC; in TLC the limit of detection is found to be 132.29 ng/spot for rabeprazole and 98.25 ng/spot for mosapride. The proposed methods can be applied to the determination of rabeprazole and mosapride in combined pharmaceutical products.

Simultaneous estimation of pantoprazole and domperidone in pure powder and a pharmaceutical formulation by high-perfomance liquid chromatography and high-performance thin-layer chromatography methods.

This paper describes validated high-performance liquid chromatography (HPLC) and high-performance thin-layer chromatography (HPTLC) methods for the simultaneous estimation of pantoprazole (PANT) and domperidone (DOM) in pure powder and capsule formulations. The HPLC separation was achieved on a Phenomenex C18 column (250 mm id, 4.6 mm, 5 pm) using 0.01 M, 6.5 pH ammonium acetate buffer-methanol-acetonitrile (30 + 40 + 30, v/v/v, pH 7.20) as the mobile phase at a flow rate of 1.0 mL/min at ambient temperature. The HPTLC separation was achieved on an aluminum-backed layer of silica gel 60F254 using ethyl acetate-methanol (60 + 40, v/v) as the mobile phase. Quantification was achieved with ultraviolet (UV) detection at 287 nm over the concentration range 400-4000 and 300-3000 ng/mL with mean recovery of 99.35+/-0.80 and 99.08+/-0.57% for PANT and DOM, respectively (HPLC method). Quantification was achieved with UV detection at 287 nm over the concentration range 80-240 and 60-180 ng/spot with mean recovery of 98.40+/-0.67 and 98.75+/-0.71% for PANT and DOM, respectively (HPTLC method). These methods are simple, precise, and sensitive, and they are applicable for the simultaneous determination of PANT and DOM in pure powder and capsule formulations.