COL1A1 Sp1 polymorphism predisposes osteoporosis by mechanisms involving changes in bone mass and bone quality.

Levels of mRNA for perforin and granzyme B are high in urinary cells from patients with acute transplant rejection.

Calcium plays an essential role in lymphocyte activation and maturation but the exact effect on gene expression is not known. In April Nature Immunology Stefan Feske and colleagues from Harvard Medical School present evidence that Ca2+-dependent signalling pathways mediate both gene induction and gene repression in activated T cells.In the absence of specific inhibitors, they looked at cell lines from two severe-combined immunodeficiency (SCID) patients that are characterised by a strong defect

GG given prenatally to mothers with a family history of atopy and postnatally for 6 months to their infants reduced the frequency of atopy by half.

Successful antiretroviral therapy results in a substantial reduction in viraemia but cannot eradicate HIV. The virus remains latent in a subset of cells where it avoids elimination by the immune system. In the April Nature Medicine, David Brooks and colleagues from the University of California at Los Angeles suggest that the thymus may be the source of latently infected cells, as latent HIV infection can occur during thymopoiesis.They studied SCID-hu (Thy/Liv) mice, in which human thymic implant

The thymus prevents autoimmunity by inducing apoptosis of the T cells that express autoreactive receptors to self peptides. But this mechanism alone is insufficient and CD4+CD25+ regulatory T cells are selected in the thymus to control autoreactive thymic escapees. In the April Nature Immunology, researchers from The Wistar Institute, Philadelphia, describe a novel mechanism of thymic selection that is involved in the generation of CD4+CD25+ regulatory T cells.Using a murine model, Jordan et al

Depletion of complement factors or the complement receptor significantly delays the onset of scrapies in a mouse model.

Progressive heart failure and death can occur following myocardial infarction due to ventricular remodelling and fibrosis. Neoangiogenesis occurs normally within the infarcted tissue, but the new capillary network is unable to support the greater demands of the hypertrophied myocardium and remaining myocytes are unable to reconstitute the necrotic tissue.In the April Nature Medicine, Kocher and colleagues Columbia University, New York show that bone marrow from adult humans can be used to help n

Hemangioma, a common tumour of infancy, is a benign vascular neoplasm of unknown aetiology. Most are small lesions, but about 10% can expand rapidly and can be life threatening. The nature of the primary defect responsible for the abnormal endothelial proliferation is unknown. In the 15 March Journal of Clinical Investigation, Eileen Boye and colleagues from Harvard Medical School show that hemangiomas are caused by clonal expansion of vascular endothelial cells.Boye et al isolated abnormal endo

Bacteria expressing invasion genes can penetrate the intestinal epithelial barrier only through cells located in Peyer's patches. But after oral administration Salmonella typhimurium bacteria deficient in invasion genes are still able to reach the spleen by an as yet unknown invasion route. In April Nature Immunology, researchers from the University of Milano-Bicocca report a mechanism that may be exploited by bacteria to spread throughout the body.Maria Rescigno and colleagues infected murine i

Smokers look older than non-smokers of the same age, probably because they have higher levels of MMP-1 (matrix metalloproteinase 1) in their skin, according to a study in 24 March Lancet. MMP-1 is a zinc-dependent metalloproteinase that degrades collagen, which is important in maintaining the mechanical/elastic properties of connective tissue in the skin.Lahmann et al from Guy's, King's and St Thomas' School of Medicine, London, used PCR to measure mRNA in the buttock skin of 14 smokers and 19 n

Angiotensin converting enzyme (ACE) and the angiotensin II type 1 receptor (AT1 R A1166C) gene polymorphism have both been associated with an increased risk of heart attack or stroke. It is not known, however, if an interaction between these two polymorphisms is responsible. In a paper published in April Heart, a team from University of Groningen, Netherlands confirms that the ACE-DD and AT1 R-CC genotypes interact to increase the risk of ischaemic events (Heart 2001, 85:458-462).Van Geel et al