The cell and developmental biology of alkaloid biosynthesis

Plants produce unique natural products as a result of gene mutation and subsequent adaptation of metabolic pathways to create new secondary metabolites. However, their biosynthesis and accumulation remains remarkably under the control of the biotic and abiotic environments. Alkaloid biosynthesis, which requires the adaptation of cellular activities to perform specialized metabolism without compromising general homeostasis, is accomplished by restricting product biosynthesis and accumulation to particular cells and to defined times of plant development. The cell and developmental biology of alkaloid biosynthesis, which is remarkably complex, evolved in part by recruiting pre-existing enzymes to perform new functions.

Pentoxifylline is not a promising treatment for multiple sclerosis in progression phase

Fourteen MS patients took pentoxifylline at varying doses for up to 24 months. In vitro production of tumor necrosis factor alpha was reduced in patients taking 2,400 to 3,200 mg/day of pentoxifylline for 12 weeks or more. Twelve of the 14 patients experienced worsening of the disease during the study according to clinical, MRI, or visual evoked potential criteria. These results provide no hint of efficacy for pentoxifylline as a treatment for MS in progression phase.

Spatial patterns of fiber types in atrophied skeletal muscle

This study examined the spatial distributions of different fiber types in the soleus muscle of control rats and in rats subjected to hindlimb unloading for 28 days. The frequencies with which muscle fibers of one type were adjacent to each other and to fibers of other types were tabulated and compared to expectations generated from Monte Carlo simulations. In the normal rat, there is a tendency for Type I fibers to avoid adjacency with each other, a tendency that persisted in the hindlimb-suspended group, despite the substantial shrinkage in size of Type I fibers. We conclude that this treatment, unlike neurogenic pathologies, does not cause any remodeling of the adjacency relations of fibers.

Deficient interferon-alpha response of newborns in comparison to adults

Human peripheral blood mononuclear cells (PBMC) respond efficiently to viral infections with interferon (IFN)-alpha production. Using Newcastle disease virus (NDV) and Sendai virus as inducers, our experiments with purified mononuclear cell populations of healthy adult volunteers showed that monocytes were the main IFN-alpha producers in these systems. Using an ELISA, which specifically recognized IFN-alpha 2, and a bioassay, in which all subtypes were detected, IFN-alpha 2 was a major subtype expressed. Furthermore, IFN-alpha release was higher after induction with NDV than after stimulation with Sendai virus. To compare the IFN-alpha response of adult PBMC to human cord blood mononuclear cells the cells were stimulated with NDV or Sendai virus. The IFN-alpha response of cord blood mononuclear cells to Sendai virus was slightly reduced compared to that of adult cells. However, IFN-alpha 2 was a major subtype produced. In contrast, when cord blood mononuclear cells were stimulated with NDV the IFN-alpha release was strongly diminished. Furthermore, IFN-alpha 2 was not the major subtype expressed. By in situ hybridization the number of IFN-alpha-producing cells was quantified. We found that 1% of adult PBMC and newborn leukocytes showed detectable IFN-alpha mRNA after stimulation with either Sendai virus or NDV. In conclusion, these data suggest that the ability of cord blood mononuclear cells to produce IFN-alpha is diminished compared to adult PBMC. This impaired IFN-alpha response is not based on a reduced number of IFN-alpha-producing cells, but rather due to underlying control mechanisms of the newborns that are different from the regulation of adult PBMC.