Reversibility of retinal adhesion in the rabbit

We have studied retinal adhesion in the rabbit using a new technique for quantifying adhesiveness by the observation of how much pigment remains adherent to the photoreceptors after separation. Previous in vitro work has shown that retinal adhesiveness falls within 3 min after enucleation, is weakened by low pH or the removal of calcium and magnesium, and is increased by cold temperature. This report shows that the effects of low pH, low calcium/magnesium and temperature are all rapidly reversible. Thus, restoring normal pH or normal calcium/magnesium will restore adhesiveness to control levels, and adhesion may be repeatedly weakened or strengthened by the adjustment of temperature or the ionic environment. The actions of pH and calcium/magnesium are in part additive, while cold temperature can maintain adhesion even in low pH or low calcium/magnesium. These findings suggest that irreversible processes such as metabolic or enzymatic decay are not primarily responsible for the loss of retinal adhesion which occurs so rapidly after enucleation or death. They also suggest that retinal adhesion is a multifactorial process.

Selection of hormone-responsive advanced breast cancer with a cytoplasmic estrogen receptor assay. Analysis of 100 cases

One hundred women with advanced breast cancer were treated with endocrine therapy alone and the clinical response was correlated with the estrogen receptor status of the tumor as determined by a fluorescent histochemical assay designed to estimate the percentage of cancer cells with high cytoplasmic estrogen binding activity. Using clinical response rates as the standards for measurement, this histochemical method showed an 84% sensitivity, a 74% specificity, a 76% positive predictive value and an 82% negative predictive value. These results indicate that the histochemical assay may serve as a supplementary means to identify hormone-responsive mammary carcinomas and as a research tool to study the biology of this group of tumors.

Pigment adherence as a measure of retinal adhesion: dependence on temperature

Retinal adhesion deteriorates rapidly after enucleation. We have developed a new in vitro method for measuring retinal adhesiveness in the rabbit that is faster than previous models, and can monitor changes sooner after enucleation. We used the percentage of retina which retained pigment after peeling from the RPE as a quantitative measure of retinal adhesiveness. We found that the failure of adhesion after death is more rapid and severe than previously reported, but can be inhibited by cold temperature. Pigment adherence was also modified by ionic and metabolic factors that have been found to affect other indices of adhesion. These results emphasize the limitations of in vitro data relative to the physiologic forces that maintain retinal adhesion in vivo.