Discordances entre les dosages de PSA : comparaison PSA,PSA libre,PSA complexé

Prostatic Specific Antigen (PSA) associated with digital rectal examination is proven to be a powerful tool in the early detection of prostatic carcinoma. The discrepancy of the results between the different methods leads to less accurate clinical diagnosis. The existence of several molecular forms of circulating PSA generate these discrepancies in total PSA determination (TPSA). The structure of immunoassay explains the differences in immunologic recognition and amounts of circulating PSA. Reliability can be obtained by accurate standardizations which reduce intertest variability, but do not increase intrinsic clinical performance of total PSA. The determinations of free (FPSA) or complexed (CPSA) PSA and more precisely the FPSA/TPSA or CPSA/TPSA ratios, seem to give more accurate and more specific answer than total PSA alone for the early diagnosis and therapeutic follow-up of prostatic carcinoma. The study of 456 patients from the Urologic Surgery Ward of Cochin Hospital including 195 patients with benign prostatic hypertrophy (BPH), 138 pa-tients with prostatic carcinoma (PC) and 123 patients without PC provides optimal threshold values for the FPSA/TPSA ratio (ratio - 18% with sensitivity = 70% and specificity = 90%). ROC analysis shows that CPSA/TPSA ratio gives the same clinical performances as FPSA/TPSA ratio.     

Anticorps monoclonaux,anticorps thérapeutiques

Discovered by Kohler and Milstein in 1975, monoclonal antibodies have found many and important applications. The most recent is their therapeutic use, for pathologies with known or suspected pathophysiologic immunological mechanisms.Inhibition of inflammatory cytokines synthesis or action, inhibition or decrease of malignant cells' proliferation, or their specific elimination, inhibition of thrombocytes aggregation, toxins neutralisation, prevention of viral invasion, inhibition of mast cells degranulation responsible for allergic reactions, are examples of the numerous current applications of these new drugs, but many others are in development.This article is a review of the use of monoclonal antibodies in therapeutics and provides information about new clinical applications.     

Rythmes biologiques,nutrition et métabolisme

Homeostatic mechanisms are not the only ones implied in metabolic balances. Any living organism, whatever its complexity, presents biologic rhythms. They can have a periodicity of about 24 h (circadian rhythms) ; shorter than 21 h (ultradian rhythms, less than a second up to several hours) ; or longer than 27 h (infradian rhythms : mensual, circannual or seasonal).Biologic rhythms have an endogenous (genetic) origin and are driven by biologic clocks, mainly by the suprachiasmatic nuclei of the anterior hypothalamus. Besides, biologic rhythms are entrained to environmental changes by exogenous factors called synchronizers such as the activity-rest cycle and day-night alternance…The spontaneous food intake behavior, the various processes involved in digestion and the metabolism of nutrients are, as all other biologic variables, submitted to rhythmic variations — but the number and nature of the oscillators responsible for their generation and control are still poorly understood and a matter of controversy, because of the complex and multifactorial character of food consumption.