The effect of vitamin E administration to pregnant women, on the concentration of linoleic acid in adipose tissue of the newborns

The composition of various lipids were measured in ten healthy newborns of mothers who were treated with 100 mg vitamin E per day, starting in the 35th week of pregnancy. The maternal serum vitamin E levels following the treatment (1.10 +/- 0.49 mg/dl) showed no increase as compared to the pretreatment values (1.06 +/- 0.38 mg/dl). There was no significant difference in serum vitamin E levels in those newborns whose mothers were treated--(0.19 +/- 0.12 mg/dl) as compared to 10 newborns whose mothers were not treated with vitamin E (0.13 +/- 0.07 mg/dl). However, there was a striking increase in the relative concentration of linoleic acid in the adipose tissue to those newborns whose mothers were treated (9.4%--versus--4.1%).     

Quantitation of phospholipid vesicles and their cholesterol content in human bile by quasi-elastic light scattering

The proportion of biliary cholesterol carried by phospholipid vesicles may be an important determinant of the lithogenicity of bile. The distribution of biliary cholesterol between vesicles and other aggregational forms is often determined by gel filtration under standard conditions. The aim of this study was to measure the proportion of biliary cholesterol in vesicles in native unprocessed bile and to compare it with values obtained by chromatography. A modified quasi-elastic light-scattering method was used to measure vesicular cholesterol in whole bile. It was suitable only for lightly pigmented biles with a relatively monodisperse population of vesicles. In ten human biles examined, the proportion of cholesterol in vesicles by gel filtration was 40 +/- 8.1% (mean +/- S.D.) by chemical measurement, and 38 +/- 7.2% by [3H]cholesterol estimation. Quasi-elastic light-scattering measurements of these biles produced vesicular cholesterol values of 36 +/- 9.4%. Chromatography may affect lipid particles in bile. Nevertheless, it provides a relatively accurate measurement of biliary cholesterol in vesicles.     

An improved procedure for quantitating mitochondrial DNA in cultured mammalian cells

A new improved method that reproducibly measures small perturbations of mitochondrial DNA in populations of cells has been developed. It is based on first obtaining a cell count and then analyzing three aliquots of cells: one for total DNA per cell by fluorometry, one for total protein per cell and one for the amount of mitochondrial DNA per microgram of total cell DNA. To quantitate mitochondrial DNA, 0, 1, 2, and 3 nanograms of mouse mtDNA purified from a plasmid are added as internal standard DNA to four 1.0-microgram samples of purified total cell DNA containing an unknown amount of mitochondrial DNA (a sample set). Three sample sets are electrophoresed in an agarose gel devoid of ethidium bromide. Following Southern transfer to nitrocellulose and hybridization to purified 32P-labeled mouse mitochondrial DNA, an autoradiogram is prepared for use as a template to locate the mitochondrial DNA bands. These bands are cut out of the nitrocellulose filters, and their 32P-content is determined using a liquid scintillation counter. For each sample set, the counts per minute is plotted against the amount of mitochondrial DNA added. The plot is linear and the negative average of the values for the three intercepts on the x-axis yields the amount of nanograms of mitochondrial DNA per microgram of total cell DNA. The method is highly reproducible with a standard deviation of approximately 9 percent. The advantages of using this method over others that have been reported are discussed.     

Rheological properties of cross-linked hyaluronan-gelatin hydrogels for tissue engineering

Hydrogels that mimic the natural extracellular matrix (ECM) are used in three-dimensional cell culture, cell therapy, and tissue engineering. A semi-synthetic ECM based on cross-linked hyaluronana offers experimental control of both composition and gel stiffness. The mechanical properties of the ECM in part determine the ultimate cell phenotype. We now describe a rheological study of synthetic ECM hydrogels with storage shear moduli that span three orders of magnitude, from 11 to 3 500 Pa, a range important for engineering of soft tissues. The concentration of the chemically modified HA and the cross-linking density were the main determinants of gel stiffness. Increase in the ratio of thiol-modified gelatin reduced gel stiffness by diluting the effective concentration of the HA component.