Quantitation of the fatty acid composition of phosphatidic acid by capillary gas chromatography electron-capture detection with picomole sensitivity

We describe a relatively simple and sensitive method to measure fentomole amounts of phosphatidic acid in cells. Phosphatidic acid was extracted from cells in the presence of 1-heptadecanoyl-2-heptadecanoyl-sn-glycero-3-phosphate as an internal standard, purified by two-dimensional thin-layer chromatography, and hydrolyzed to its constituent free fatty acids which were then derivatized to the corresponding pentafluorobenzyl esters. Pentafluorobenzyl esters of fatty acids were analyzed by gas chromatography with electron-capture detection. Long-chain fatty acids were resolved with excellent signal-to-noise ratios. Using heptadecanoic acid as an internal standard for quantitation, as little as 1 fmol of pentafluorobenzyl ester of stearic acid was detected with a linear response up to 10 pmol. Linear detector responses were obtained for all major classes of fatty acids. For phosphatidic acid measurement, the detection limit was at least 50 fmol thus achieving a 1000-fold increase in sensitivity compared to the most sensitive of the previously described methods. An example is provided of quantitating phosphatidic acid from minute amounts of biological samples such as islets of Langerhans.     

Determination of photoperiod response characteristics using a greenhouse

The photoperiod response characteristics of two cultivars of seven long-day species of crop plants were determined by seeding at 33 biweekly intervals in a greenhouse at 49? 43′ N Latitude. Parameters of a segmented linear regression were estimated using a non-linear computer program. This gave good estimates of the length of the basic vegetative and reproductive phases, the photoperiod sensitivity and minimum optimal photoperiods. It was apparent that the photoperiod of importance was that of the day of floral initiation. If the plant is old enough and the photoperiod of the day is not inhibitory, initiation will occur. At certain times of the year, the photoperiod changes so rapidly that flower initiation is prevented. Using this method of analysis, comparisons of large numbers of genotypes can be made.     

Increased Production of Endogenous Pyrogen and Lysozyme by Blood Monocytes in Sarcoidosis

Blood monocytes from patients with sarcoidosis were incubated in vitro, and secretion of endogenous pyrogen (EP), the protein which mediates fever, and lysozyme (L) were measured. After incubation with endotoxin, monocytes from 5 patients with sarcoidosis released twice as much EP as did monocytes from normal individuals (p < .001). Initial 24-hr secretion of L by monocytes from 6 of 11 additional patients with sarcoidosis exceeded the normal range of values for cells from 11 age- and sex-matched control individuals. Cells with initially augmented secretion rates continued to secrete increased amounts of L for 3 days. A correlation was noted between in vitro secretion of L by monocytes and serum levels of L in the same patient. These studies indicate that circulating mononuclear cells in some patients with sarcoidosis have an increased capacity to secrete EP and/or L prior to tissue localization.     

Human milk fat globule membrane glycoproteins express blood group-related determinants primarily on mucin-like epithelial membrane antigens and gp70.

Milk fat globule membranes (MFGM) were prepared from 21 human milks and dot-blotted. MFGM samples were compared with reference to 8 blood group-related antigens reactive with monoclonal antibodies and lectins. All preparations contained epithelial membrane antigen (EMA) and the majority was positive for type 1 Lewis a and b antigens, whereas only trace amounts of sialyl Lewis a were found. For type 2 Lewis antigens, most MFGM reacted intensely for X, but only weakly and infrequently for the Y antigen. Reactivities for H were also infrequent and antigens related to A and/or B (types 1 and 2) were not found. Western blot analyses established that these antigenic determinants were borne mainly by mucin-like components and gp70.     

Nonlinear optical microscopy in decoding arterial diseases

Pathological understanding of arterial diseases is mainly attributable to histological observations based on conventional tissue staining protocols. The emerging development of nonlinear optical microscopy (NLOM), particularly in second-harmonic generation, two-photon excited fluorescence and coherent Raman scattering, provides a new venue to visualize pathological changes in the extracellular matrix caused by atherosclerosis progression. These techniques in general require minimal tissue preparation and offer rapid three-dimensional imaging. The capability of label-free microscopic imaging enables disease impact to be studied directly on the bulk artery tissue, thus minimally perturbing the sample. In this review, we look at recent progress in applications related to arterial disease imaging using various forms of NLOM.