Oral disease in Africa: a challenge to change oral health priorities

Colonial and other unsustainable oral health strategies exported to Africa have failed to improve oral health in the region. An alternative way of interpreting and responding to the problems of oral health in Africa is presented. It begins with a systematic interpretation of the health information available, using the application of the basic epidemiological principle of defining a specific health problem by describing its prevalence, severity (morbidity, mortality) and age adjusted distribution in the population. African oral disease priorities determined in this way are shown to be fundamentally different from those perceived previously. It is recommended that this new approach be used in customising a viable set of oral health policies and intervention strategies for each individual African community.     

Prosthetic valve endocarditis after heart catheterization

It is accepted that patients with valvular disease or valvular prosthesis should be protected against endocarditis during procedures causing bacteriemia. On the other hand it has been shown that bacteriemia occurs during catheterization. Thus, protection against endocarditis for patients undergoing catheterization deserves more consideration, specially among patients with prosthetic valves. Moved by the fatal outcome of one of our patients with postcatheterization prosthetic valve endocarditis, the authors leave an open discussion about this subject.     

Postnatal development of brain TRH, serum TSH and thyroid hormones in the male and female rat

The postnatal development of immunoreactive TRH in the central nervous system (CNS), serum TSH and thyroid hormones was studied in both male and female normal rats. While in most structures of the CNS, TRH increased until day 20-30, serum TSH values peaked at day 15 as did T4. Significant differences were also obtained between both sexes in these parameters. These data further support the fact that pituitary-thyroid axis maturation is independent of brain TRH.     

Alterations in the phenotype of hairy cells during culture in the presence of PHA: requirement for T cells

Culture studies of peripheral blood mononuclear cells from 7 entirely typical cases of hairy cell leukemia showed that after culture in the presence of PHA for 2--5 days, the predominant cell type changed from E- SIg+ CIg+ gamma FcR+ muFcR+ hairy cells to an E+ SIg- CIg- gamma FcR- muFcR- population of transformed cells derived from hairy cells. Depletion and readdition experiments demonstrated that cell-to-cell contact with T cells was necessary for the phenotypic change, while several observations indicated that the E+ population was not derived from T cells present before culture. The E positivity of the cultured cells was shown to be due to the possession of E receptor not acquired from the culture fluid, but the cells differed from true T cells in lacking both mature and immature T-cell antigens. The relevance of these in vitro observations to the continuing controversy concerning the nature of the hairy cell and to the in vivo fluctuations in immunologic phenotype not infrequently observed in hairy cell leukemia is briefly discussed.     

Pro-NGF isolated from the human brain affected by Alzheimer's disease induces neuronal apoptosis mediated by p75NTR

The pro-form of nerve growth factor (pro-NGF) has been shown to be a high affinity ligand for p75NTR and to induce apoptosis through this receptor. It has been reported that pro-NGF, rather than mature NGF, is the predominant form of this neurotrophin in human brain. In the present work we studied the potential involvement of pro-NGF purified from human brains affected by Alzheimer's disease (AD), where it is especially abundant, in the neuronal apoptosis observed in this disease. Western blot analysis of human brain tissue showed the existence of several pro-NGF forms. Some of these pro-NGF forms were significantly increased in AD brain cortex in a disease stage-dependent manner. Pro-NGF, purified by chromatography from human AD brains, induced apoptotic cell death in sympathetic neurons and in a p75NTR stably transfected cell line. Blocking p75NTR in cell culture abolished neuronal apoptosis caused by pro-NGF. p75NTR-transfected cells underwent apoptosis in the presence of pro-NGF while control wild-type cells did not. Taken together, these results indicate that pro-NGF purified from AD human brains can induce apoptosis in neuronal cell cultures through its interaction with the p75NTR receptor.