The beta-gal interferon assay: a new, precise and sensitive method

Cells of a human glioblastoma line were stably transfected with a glial fibrillary acidic protein (GFAP) promoter sequence/lacZ reporter gene. Following this modification, they produced Escherichia coli beta-galactosidase constitutively in amounts that could be measured through their conversion of an added fluorophore into a product readily estimated by fluorimetry. Human interferons (IFN) selectively and in a dose-dependent manner reduce the formation of beta-galactosidase in this system. We have used it as the basis for a novel assay that is sensitive (4-40 pg/ml), precise, completed in 30 h, and applicable to both type I and type II human IFNs. Statistical analysis showed interassay relative standard deviations ranging from 5% to 11%, and most individual assays revealed potencies with limits of error within 85%-115%. Neither partially trypsin-digested IFN nor the other cytokines and mitogens we tested reacted in this system, except for tumor necrosis factor-alpha (TNF-alpha). The high selectivity was further shown by the loss of response to IFN in the presence of the appropriate specific anti-IFN or anti-IFN-gamma receptor antibodies.     

Characterization of axenic Pseudomonas fragi and Escherichia coli biofilms that inhibit corrosion of SAE 1018 steel

The purpose of this study was to evaluate the effect of redesigning the education program from individual instructional sessions to a format where the majority of instruction was provided through small group classes. Patient outcomes of lifestyle changes as evidenced by weight loss, improved glycemic control, adoption of a consistent pattern of blood glucose monitoring, and increased physical activity were evaluated using a physician satisfaction survey and a patient satisfaction and lifestyle change survey. The findings indicate that the changes in the education program accommodated a variety of needs; facilitated cost-effectiveness; were convenient for the patients, educators, and physicians; and still promoted adaptive lifestyle changes in behavior leading to improved glycemic control, increased levels of physical activity, and weight loss in persons with type 2 diabetes.     

Guidelines for the Application of Vacuum Contactors

The overvoltage phenomena associated with switching currents in vacuum and their effects on motor insulation are described in some detail, and a practical guideline for the application of overvoltage protective devices is presented.     

Glycogen levels in human term placental disks, umbilical cords, and membranes

Glycogen in the placenta and its appendages is important for fetal well-being. The precise location of the glycogen stores, however, is unknown. This study was initiated to quantitate glycogen levels at well-defined sampling sites in more than 641 samples from 10 uncomplicated pregnancies and to correlate these glycogen levels with clinical and morphological variables. By biochemical assay, glycogen levels were greatest in the midumbilical cord section (29.08 +/- 1.18 mg/g dry wt) and lowest in the amnionic membrane (2.31 +/- 0.08 mg/g dry wt). Within the placental disk, parenchymal glycogen levels were greatest near the cord insertion (9.31 +/- 2.68 mg/g dry wt) and lowest at the periphery (5.71 +/- 1.14 mg/g dry wt). The midumbilical cord glycogen level showed strong direct correlations (P < .001) with birth weight, umbilical cord weight, and total calculated umbilical cord glycogen and somewhat lower but significant (P < .037) direct correlations with the calculated mean umbilical cord glycogen level, total calculated placental glycogen content, and placental weight. The glycogen level in the middisk parenchymal section from the fetal surface correlated directly with gestational age. Periodic acid-Schiff stains showed that magenta glycogen granules were most abundant in the cytoplasm of the vascular smooth muscle cells. These data show significant variations in glycogen levels among sampling sites. Definition of the precise sampling site is important for clinicopathologic studies of placental glycogen and for interstudy correlations.     

A polychrome stain for conventionally fixed paraffin-embedded woody plant tissues

A method for the differential staining of conventionally fixed paraffin-embedded woody plant tissue is described. A five-component stain combination is used with Bismarck Brown, included to avoid the stain variability, precipitation, and overstaining problems often encountered when using safranin.