Separation of Fatty Acid Dimethyl Esters on an Ionic Liquid Gas Chromatographic Column.

An ionic liquid (IL) 111 column was compared with other commonly employed stationary phases including polydimethyl siloxane and polyethylene glycol for the separation of fatty acid monomethyl and dimethyl esters. The fatty acid esters employed in this study were derived from metathesis reactions of vegetable oils both with and without olefins. The IL 111 column demonstrated enhanced performance compared with conventional columns for the separation of these esters. These advantages included significantly enhanced retention of dimethyl esters relative to monomethyl esters, excellent cis/trans isomer separation and the ability to analyze higher carbon number dimethyl esters. As a result, these columns are highly suited for the analysis of mixtures of mono- and dimethyl fatty acid esters found in lipid metathesis reaction products or to determine monofunctional impurities in samples of commercial dimethyl esters.

Cerebral vasospasm in traumatic brain injury.

Vasospasm following traumatic brain injury (TBI) may dramatically affect the neurological and functional recovery of a vulnerable patient population. While the reported incidence of traumatic vasospasm ranges from 19%-68%, the true incidence remains unknown due to variability in protocols for its detection. Only 3.9%-16.6% of patients exhibit clinical deficits. Compared to vasospasm resulting from aneurysmal SAH (aSAH), the onset occurs earlier and the duration is shorter. Overall, the clinical course tends to be milder, although extreme cases may occur. Traumatic vasospasm can occur in the absence of subarachnoid hemorrhage. Surveillance transcranial Doppler ultrasonography (TCD) has been utilized to monitor for radiographic vasospasm following TBI. However, effective treatment modalities remain limited. Hypertension and hypervolemia, the mainstays of treatment of vasospasm associated with aSAH, must be used judiciously in TBI patients, and calcium-channel blockers have offered mixed clinical results. Currently, the paucity of large prospective cohort studies and level-one data limits the ability to form evidence-based recommendations regarding the diagnosis and management of vasospasm associated with TBI.

Differentiation of Solenopsis invicta social forms using high resolution melt PCR.

Solenopsis invicta Buren (red imported fire ant) are invasive pests that have the capability of major destructive impacts on lifestyle, ecology and economy. Control of this species is dependent, in part, upon ability to estimate the potential spread from newly discovered nests. The potential for spread and the spread characteristics differ between monogyne and polygyne social forms. Prior to this study, differentiation of the two social forms in laboratory test samples commonly used a method involving restriction endonuclease digestion of an amplified Gp-9 fragment. Success of this assay is limited by the quality of DNA, which in the field-collected insects may be affected by temporary storage in unfavourable conditions. Here, we describe an alternative and highly objective assay based upon a high resolution melt technique following preamplification of a significantly shorter Gp-9 fragment than that required for restriction endonuclease digestion. We demonstrate the application of this assay to a S. invicta incursion in Queensland, Australia, using field samples from which DNA may be partially degraded. The reductions in hands-on requirements and overall duration of the assay underpin its suitability for high-throughput testing.

Two measurement techniques for assessing subtalar joint position: a reliability study.

Proper assessment of the subtalar joint is critical for foot and ankle evaluation. Yet, reliability of open kinetic chain goniometric measurements of the subtalar joint has been poor. Two alternative techniques, navicular height and calcaneal position with an inclinometer, have been reported in the literature but lack reliability assessment. The purpose of this study was to determine the intertester and intratester reliability of navicular height and calcaneal position using an inclinometer. Thirty healthy, volunteer subjects (22 females, age 24 +/- 3.6 years; eight males, age 25 +/- 5.1 years) participated in this study. Two testers performed repeated measures on both feet of each subject (N = 60) during two testing sessions. Testers determined the 1) subtalar neutral position, 2) resting position, and 3) difference between these two measurements using an inclinometer for calcaneal position and navicular height. Intratester and intertester reliabilities (ICC 2, 1), standard errors of measurement, and 95% confidence intervals were determined. Intertester and intratester reliability for calcaneal position ranged from .68 to .91 for all measurements. Intertester and intratester reliability for navicular height ranged from .73 to .96 for all measurements. We conclude that these weight-bearing measurement techniques are reliable and acceptable for clinical and research purposes as measured. In addition, we hypothesize that these measurement techniques are simpler than previously described open kinetic chain methods.

Depletion of complement by light and porphyrin does not depend on sequential activation.

The mechanism of complement depletion from human serum fortified with porphyrin and irradiated with light has been reinvestigated, with the conclusion that it did not depend on the normal sequence of complement activation. Thus, disappearance of the activities of C3, C4, and C5 was not dependent on divalent cations. Purified C3-C7 were labile to porphyrin/light treatment in the absence of other components. The depletion of C4 was not prevented by potent inhibitors of C1 and, unlike the depletion of C4 seen in response to aggregated gamma globulin, was insensitive to change in temperature. Electrophoresis showed an alteration of C3 unlike that caused by cobra venom factor and that light/porphyrin treatment nonspecifically altered many serum proteins.

Systematic discovery and evaluation of complement inhibitors.

Methods are presented for an orderly search of a chemical file for complement inhibitors. Compounds are initially examined for intrinsic activity against dilute human components in vitro, using hemolytic assays to detect inhibitors of fluid phase C1, of late components lysis of EAC142, and of CVF-induced passive lysis of AET-treated human erythrocytes. Active compounds are then examined for activity against undiluted serum in vitro. Compounds passing this test are examined for activity in vivo against serum complement and complement-dependent lesions, viz. Forssman vasculitis, the reverse passive Arthus phenomenon, and Forssman shock. Methods are given for quantitation of these lesions.

Hemolytic anemias associated with deficient or dysfunctional spectrin.

Elliptocytes from patients with hereditary elliptocytosis (HE) form elliptical ghosts and membrane skeletons. The composition of HE skeletons is quantitatively normal; however, in some but not all kindreds the major membrane skeletal protein, spectrin, is abnormally heat-sensitive, presumably due to a molecular defect which diminishes its conformational stability. Red cells from four mutants of the common house mouse (Mus musculus) with severe, recessive hemolytic anemias show marked membrane budding, fragmentation, and spherocytosis, which suggest membrane instability. Ghosts spontaneously vesiculate and are spectrin-deficient. The amount of spectrin varies from none to one-half the normal amount and correlates with the clinical severity of the four mutations. The cause of this deficiency remains to be determined. These mutants prove that spectrin is a critical determinant of membrane structural integrity and provide a unique opportunity to test, in intact red cells, putative functions of spectrin. Spectrin extracted from ghosts at low ionic strength is heterogeneous. At physiologic ionic strengths part (46 +/- 5%) is polymerized (P-spectrin) and complexed with actin, and part remains as nonpolymerized spectrin dimers and tetramers (NP-spectrin). We postulate that these are native membrane species which exist in a metabolically controlled equilibrium in vivo and that the proportion of these species regulates membrane shape, strength, and flexibility.