Transplantation and preservation of tissue-typized skin in burns]

At the Department of Plastic Surgery and Burns, Berufsgenossenschaftliche Unfalklinik Ludwigshafen-Oggersheim, a skinbank with typed skin has been established. The storage system consists of deep-freezing at -196 degrees C in liquid nitrogen. The transplantation of HL-A typed skin was evaluated from the clinical and histological point of view. Due to the effort necessary for such an undertaking this method is critically reviewed.     

Interference microscopic determinations of dry mass of cell nuclei of normal and dysplastic epithelium, carcinoma in situ and cervical carcinoma cultivated in vitro (author's transl)]

Dry mass of cell nuclei was studied in 34 explant cultures of normal epithelium (8), persisting dysplasias (7), Ca in situ (9) and cervical carcinomas (10) by interference microscopic determination. Dysplasias, Ca in situ and carcinomas can be distinguished from normal epithelium by a significantly higher dry mass value. Such a difference does not exist between dysplasia and Ca in situ. The percentage of dispersion of the dry mass is significantly higher in carcinomas than in all other examined tissues. The biological meaning of these results is discussed. The interference microscopic determination of dry mass of the cell nuclei is a suitable parameter for the characterization of properties of cervical carcinomas and their intraepithelial prestages cultivated in vitro.     

Practical application of logistic function to the growth of experimental tumors

The properties of the logistic law of growth (Verhulst-Pearl) and a simple method for computing of statistical approximation are described. Two parameters are estimated: the generation rate c and the mortality rate c0, although the real biological processes are of greater complexity. The logistic law is modified by an additional term concerning the prefinal decline in the last life span. To prove the curve fitting to tumour growth by the modified logistic function the total number of Ehrlich ascites tumour cells was measured in 144 mice at 12 different times after inoculation. The accuracy of the curve fitting proved to be very good. Therefore the logistic function modified by an additional term for the final stages, is particularly suited for the characterization of Ehrlich ascites tumour growth and its changes.