Aplastic anemia: analysis of stromal cell function in long-term marrow cultures.

Marrow samples from 89 patients with aplastic anemia (AA) were evaluated for their ability to grow stromal layers in standard long-term marrow cultures (LTMCs). Results were highly variable: 6.8% failed to grow any stromal cells (group I); 42.

Increased birth weights of National Wilms' Tumor Study patients suggest a growth factor excess.

An analysis of over 1800 patients with Wilms' tumor revealed significantly higher birth weights than newborns in the general United States population. The highest birth weights were found not only in patients diagnosed with the Beckwith-Wiedemann syndrome (mean, 3.78 kg), as had been expected, but also in those with hemihypertrophy (3.

Comparison of transmission rates of HIV-1 and HIV-2 in a cohort of prostitutes in Senegal.

To explore the biological similarities and differences between the HIV-1 and HIV-2 viruses, we model the probability of male-to-female transmission of either HIV virus as a function of the number of sexual partners, the prevalence of the viruses and the infectivity per contact. Using maximum likelihood estimation theory and data from a prospective study of registered female prostitutes in Dakar, Senegal, we estimate and compare the infectivities of HIV-1 and HIV-2. Graphical goodness-of-fit methods are used to show that our model fits the data well.

Prevalence and risk determinants of human immunodeficiency virus type 2 (HIV-2) and human immunodeficiency virus type 1 (HIV-1) in west African female prostitutes.

The authors studied the prevalence and risk determinants for human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) in female prostitutes from Dakar (1985-1990), Ziguinchor (1987-1990), and Kaolack (1987-1990), Senegal, West Africa. Each cohort showed a distinct distribution of HIVs: 10.0% HIV-2 and 4.

Statistical properties of the NOAEL.

The use of the no observed adverse effect level (NOAEL) in setting allowable exposure levels for noncancer endpoints is a source of controversy. Based on computer simulations and empirical studies, several authors have criticized the use of the NOAEL in terms of its sensitivity to sample size and its high sampling variability from experiment to experiment. The purpose of this paper is to derive the statistical distribution of the NOAEL.