Please quote Nature Medicine as the source of these items.

The September 2005 issue of Nature Medicine is available online.

Nature Medicine

Studying the formation of lymph vessels—which are involved in disorders ranging from inflammation to cancer—has been hindered by the lack of a model that could be genetically manipulated. In the September issue of Nature Medicine, Annelii Ny and colleagues present tadpoles of the African clawed frog Xenopus laevis as a model for investigating the development of lymph vessels.

The researchers subjected tadpoles to lymphangiography, a radiographic technique for examining anatomy, and found that lymph vessels form via two different pathways—one pathway shared by mammals and the other shared by birds. They also studied the effects of genetically modifying the expression of two proteins that mediate the development of lymph vessels.

Based on their results, the researchers suggest that the X. laevis tadpoles could be used for detailed anatomical investigation and the roles of lymph vessels in disease.

Nature Medicine

Research published in the September issue of Nature Medicine may help minimize the spread of prion diseases in the human body.

Prion diseases, like BSE (bovine spongiform encephalopathy) and CJD (Creutzfeldt-Jakob disease) are caused by a misfolded prion protein referred to as PrP^Sc. Minimizing spread of the disease could be facilitated by the ability to detect PrP^Sc in blood. Claudio Soto and colleagues have devised an automated method, termed protein misfolding cyclic amplification, to help do just that.

The extremely small amount of PrP^Sc that appears in blood makes it difficult to detect it and diagnose the disease. But the researchers' new technique, analogous to polymerase chain reaction for amplifying tiny samples of genetic material, amplifies PrP^Sc in the test tube, which allows the detection of PrP^Sc with 89% sensitivity (a measure of the probability of correct diagnosis) and 100% specificity (i.e., the method detects no false positives).

This is the first time PrP^Sc has been biochemically detected in the blood, so the authors have raised several issues for discussion. These issues include investigating whether all diseased animals carry PrP^Sc in their blood, and how early and sensitive diagnosis will facilitate therapeutic intervention before the appearance of clinical signs and permanent brain damage.