Statistical model of the natural history of cervical carcinoma. II. Estimates of the transition time from dysplasia to carcinoma in situ.

Estimates are presented of the transition probabilities and transition times from dysplasia to carcinoma in situ of the uterine cervix based on a statistical model of the natural history of this disease. The estimates, obtained from a longitudinal study of 557 women, were contrasted with prevalence rates obtained in a self-selected sample of over 11,000 women from Barbados, West Indies. These two independent sets of estimates, based on two different experimental designs, were shown to be concordant.

Studies on the leukocytosis and lymphocytosis induced by Bordetella pertussis. 3. The distribution of transfused lymphocytes in pertussis-treated and normal mice.

Peripheral blood lymphocytes were isolated from normal mice and mice undergoing pertussis-induced lymphocytosis. After labeling in vitro with tritiated uridine the cells were transfused into normal or pertussis-treated mice. It was found that the lymphocytes from pertussis-treated mice entered the lymph nodes of both normal mice and pertussis-treated mice to a significantly lesser extent than did normal lymphocytes which had been transfused into either class of recipient.

Insertion of Lippes loop by nurse-midwives and doctors.

Follow-up studies of 7 to 19 months of two groups of 500 women each in Barbados, in one of which a Lippes loop had been inserted by a doctor and in the other by a nurse-midwife, showed a slightly higher incidence of pregnancy and expulsion of the loop in the second group, though the difference was not statistically significant. The insertion of loops by paramedical personnel when this is an economic necessity is thought not to be contraindicated, but adequate training is essential.

Studies on streptococcal bacteriophages. I. Burst size and intracellular growth of group A and group C streptococcal bacteriophages.

Evidence has been presented that the burst size in the Group A and Group C streptococcal phage-host systems are in general similar producing approximately 13 phage particles per infected coccus. The exception was the C1 phage which produced 10 times more virus particles than all the other phages tested. The eclipse period for the A25 phage-host system was found to extend for 34 min, while the C1 phage were found as early as 10 min after infection.