Cryosurgery for neoplasia

Certain laboratory findings are presented which we think directly relate to the clinical problems of cryosurgery. Our experience in dealing with a variety of neoplasms is recorded. It is our opinion that the majority of skin tumours, benign and malignant, are best treated in this way and the advantages over radiotherapy and conventional excision are pointed out. Cryotherapeutic results on large tumours such as sarcomas and rectal carcinomas we regard as less satisfactory because of technical reasons.

Cryoprostatectomy on a highly selected group of patients has produced encouraging results although we would still regard this method of treatment as in its infancy and requiring further assessment. A brief comment is made on 33 cases of benign enlargement and 3 carcinomas of the prostate.

Cytodifferentiation and membrane transport properties in LK sheep red cells

Young cells produced in LK sheep during rapid hematopoiesis after massive hemorrhage contain more K than the cells which are normally released into the circulation. The K content in these new cells falls to that characteristic of mature LK cells after a few days in the circulation. K transport properties in young and old cells before and after massive bleeding were studied. Young and old cells were separated by means of a density gradient centrifugation technique. Evidence showing that younger cells are found in the lower density fractions is presented. Active transport of K in the lightest fraction as measured by strophanthidin-sensitive influx was four to five times greater in red cells drawn 6 days after massive bleeding while the K leak as measured by strophanthidin-insensitive influx was only slightly larger. No change after bleeding was observed in older cells which had been present in the circulation prior to the hemorrhage. It is concluded that the high K content of young cells produced in LK sheep after bleeding is due to temporary retention of membrane K transport properties characteristic of HK cells. Thus, genetically determined modification of membrane transport properties has been shown to occur in nondividing circulating red cells.