Assessment of proliferation during maturation of the B lymphoid lineage in normal human bone marrow

Different stages of B lymphoid maturation were identified in normal bone marrow using multiple cell surface markers. The proliferation status of each of these maturational stages was determined by simultaneous quantitative DNA analysis on a flow cytometer. The technique used to quantify these parameters preserved the cell surface immunofluorescence, the light scattering properties and the stoichiometric binding to DNA. The proliferating cells were confined to a distinct population of cells expressing CD10. The number of proliferating cells in these populations was relatively constant among 12 separate bone marrow samples. The data suggest that the timing and rate of proliferation of cells within a single lineage may be a preprogrammed aspect of normal maturation.     

Formation of duodenal atresias in fibroblast growth factor receptor 2IIIb-/- mouse embryos occurs in the absence of an endodermal plug

PurposeDuodenal atresia in humans has been hypothesized to arise from a failure of the duodenal lumen to recanalize after formation of an endodermal plug. Recently, mutations in the fibroblast growth factor receptor 2 gene (Fgfr2IIIb) have been shown to cause atretic defects of the duodenum in mice. However, work in rats suggests that murine species do not form an endodermal plug during normal duodenal development. These lines of data led us to hypothesize that mice are able to form a duodenal atresia in the absence of an endodermal plug. To test this hypothesis, we examined duodenal development in wild-type and Fgfr2IIIb?/? embryos.MethodsParaffin sections were generated for H&;E, E-cadherin, or terminal deoxynucleotidyl transferase-mediated X-dUTP nick end labeling staining from Fgfr2IIIb?/? and wild-type embryos between embryonic days (E) 10.5 and E14.5. Sections were photographed and reconstructed into 3-dimensional display using Adobe Photoshop and Amira Visage software.ResultsNormal mouse duodenum does not form an endodermal plug, although a plug does form in the pyloric region of the stomach at E14.5. Fgfr2IIIb?/? embryos experience significant apoptosis in the duodenal region at E10.5, followed by the disappearance of the endoderm in the atretic precursor by E11.5. Thereafter, the mesoderm of the atretic precursor involutes over the next 2 days in the absence of further apoptosis. Interestingly, an endodermal plug was not observed at any point during the formation of a duodenal atresia.ConclusionsThese results suggest that duodenal atresia in the Fgfr2IIIb?/? model does not arise from persistence of an epithelial plug. Rather it appears to result from the loss of the endoderm because of apoptosis very early in development.     

Hemosorption - a method of rapid elimination of cholesterol from the plasma and its effect on the regression of experimental atherosclerosis

Hemosorption is a method of rapid control of hypercholesterolemia. A study of hemocompatibility of an alumosilicate sorbent which is relatively selective with respect to cholesterol demonstrated a possibility of its being used in hemosorption devices. Rabbits with spontaneous regression of two-month duration were given three hemosorption sessions. A drop in cholesterol and triglycerides was noted after each session. By the end of the experiment, the area of aortal atherosclerotic lesion was reduced twofold as compared to the controls (19% vs. 41%). Rapid regression of diffuse lipid deposits from the surface and marginal zones of the patches was observed. "New" secondary lipid deposits were absent. A possibility of using hemosorption in patients with pronounced hypercholesterolemia is discussed.