Brain microvessel endothelial cells in tissue culture: a model for study of blood-brain barrier permeability.

Endothelial cells were prepared from bovine microvessels and grown in tissue culture. They contained factor VIII/von Willebrand antigen, the most specific market available for determination of the endothelial origin of cells in culture. The cultured cells formed complex tight junctions and contained few pinocytotic vessels.

Hexose transport in microvascular endothelial cells cultured from bovine retina.

The nature of glucose transport at the microvascular blood-retinal barrier was studied using primary cultures of microvascular endothelial cells from bovine retina. Uptake of 3-O-methyl-D-glucose (3MG), a non-metabolizable glucose analogue, was rapid and equilibrative. 3MG uptake could be inhibited by traditional glucose transport inhibitors such as phloretin, phlorizin and cytochalasin B but not by agents that deplete intracellular ATP (2,4-dinitrophenol) or that abolish the sodium gradient (ouabain).

Primary culture of microvascular endothelial cells from bovine retina: selective growth using fibronectin coated substrate and plasma derived serum.

To provide an in vitro system for studying retinal capillary function we have developed methods for isolation and culture of microvascular endothelial cells from retina. Retinal microvessels were isolated by homogenization of the retina and collection of the microvessels onto nylon mesh. Treatment of the isolated microvessels with collagenase and dispase followed by Percoll gradient centrifugation yielded endothelial cells that were largely free of pericytes.

Primary culture of capillary endothelium from rat brain.

To provide an in vitro system for studies of brain capillary function we developed a method for culture of brain capillary endothelial cells. Capillaries were isolated from rat brain and enzymatically treated to remove the basement membrane and contaminating pericytes. Subsequent Percoll gradient centrifugation resulted in a homogeneous population of capillary endothelial cells that attached to a collagen substrate and incorporated [3H]thymidine.

The causes of low oestrogen excretion in pregnancy: the development of diagnostic methods for the antenatal detection of familial congenital adrenocortical hypoplasia.

A pregnancy producing a boy with congeital adrenocortical hypoplasia is described. Consistently low oestrogen excretion, less than 10 umol/24 h, was not associated with any anatomical abnormality or diminished growth of the fetus as judged by ultrasound examination. Fetoplacental steroid sulphatase definciency was excluded by finding normal maternal excretion of oestrogen precursors, the 3Beta-hydroxy-5-ene steroid sulphates.

Sustained growth and three-dimensional organization of primary mammary tumor epithelial cells embedded in collagen gels.

We have developed a method for embedding cells within a collagen matrix which allows sustained growth of mouse mammary tumor epithelial cells in primary culture. A characteristic and reproducible pattern of organization and growth occurs: the cells rearrange themselves and produce duct-like structures extending into the matrix, resulting in a three-dimensional outgrowth. Autoradiography showed continuous [3H]thymidine incorporation during 8 weeks in culture.

Glucocorticoid regulation of prolactin receptors on mammary cells in culture.

Mouse mammary epithelial cultures were examined for the ability to specifically bind [125I]PRL after cultivation on floating collagen gels. Corticosterone, particularly hydrocortisone, were effective in increasing the ability of mouse mammary cells to bind [125I]PRL. The absence of a glucocorticoid in the medium resulted in a loss of PRL binding during the 3 days in culture.

Long-term organ culture of mouse mammary gland.

A method for maintaining mouse mammary gland in organ culture for periods of at least 30 days is described. Strips of the number four mammary glands were cultured in individual tubes while fully submerged in Medium 199 supplemented with insulin, aldosterone, ovine prolactin and bovine growth hormone. Exchange processes were aided by slowly rotating the tubes during culture.

Simple GLC determination of ethylene oxide and its reaction products in drugs and formulations.

Convenient rapid GLC methods for the estimation of residual ethylene oxide, ethylene chlorohydrin, and ethylene glycol in ethylene oxide-sterilized bulk drugs and formulations prepared therefrom are described. Ethylene oxide was chromatographed using a porous polymer column; ethylene chlorohydrin and ethylene glycol were chromatographed using either polyethylene glycol 400 or a porous polymer column. All three residuals were determined from the same sample preparation for each type of drug or formulation examined.

Isolation of Atypical Candida albicans from the North Sea.

Isolates of Candida albicans with sparse filamentation and weak fermentation were isolated from the surface microlayer of the North Sea, but not from subsurface waters. Such atypical isolates may be misidentified by using normal taxonomic procedures.

The effect of synchronous and asynchronous egg transfer on foetal weight in mice selected for large and small body size.

The weight difference between large, small and unselected strains of mice were maintained when blastocysts of each genotype were transferred to unselected control recipients, suggesting that foetal genotype was an important factor in determining prenatal body size. The asynchronous transfer of large, small and unselected embryos resulted in a highly significant (P less than 0-001) elevation of foetal weight compared with synchronously transferred groups, genetically small mice attaining a foetal weight greater than the normal large strain. This result suggested that foetal genotype did not limit the capacity of each strain for prenatal growth.

Decreased unscheduled DNA synthesis in nondividing aged WI38 cells.

The ability of cells from young and old cultures of WI38 human fibroblasts to undergo unscheduled DNA synthesis was studied. Following inhibition of semi-conservative synthesis in media lacking arginine and containing a hydroxyurea block, cells were irradiated with u.v.

Evaluation of commercial systems for the identification of clinical yeast isolates.

The Analytab Products Inc. (API), Micro-Drop (MD), and Uni-Yeast-Tek (UYT) systems for the presumptive identification of common clinical yeast isolates were compared with the oxidation-fermentation (OF) and a conventional procedure. With 229 coded isolates, the identification accuracies were API 94, MD 83, OF 82, and UYT 99%.

Evaluation of the Uni-Yeast-Tek kit for the identification of medically important yeasts.

The Uni-Yeast-Tek system, a commercially prepared kit and scheme for the rapid identification of medically important yeasts (Corning Medical), was evaluated in comparison with a conventional procedure in the identification of 623 yeasts. The system permitted the presumptive identification of 99.8% of 436 isolates representing 16 common species commonly isolated in the clinical laboratory.