Autologous platelet gel and its clinical application.

Platelets are attracted to a wound or injury site stimulating the clotting and healing cascades. Degranulated platelets release numerous substances including proteins known as growth factors. Growth factors signal undifferentiated stem cells to the site, promote cell mitosis, and stimulate osteogenesis and angiogenesis. Cytokines, which attract neutrophils, are also released from platelet granules. Concentrating platelets 4x to 5x the baseline level accelerates the healing process. When platelet rich plasma is mixed with an activator, a platelet gel will form. Clinical applications of platelet gel are numerous. Some benefits include a marked decrease in post-surgical swelling and bruising, reduction in surgical site pain, elimination of drains, and acceleration of bone growth and soft tissue healing. Scientific publications support that autologous biomaterial accelerates the healing process.

Aging and its theories.

Several factors (the lengthening of the average and, to a lesser extent, of the maximum human life span; the increase in percentage of elderly in the population and in the proportion of the national expenditure utilized by the elderly) have stimulated and continue to expand the study of aging. Recently, the view of aging as an extremely complex multifactorial process has replaced the earlier search for a distinct cause such as a single gene or the decline of a key body system. This mini review keeps in mind the multiplicity of mechanisms regulating aging; examines them at the molecular, cellular, and systemic levels; and explores the possibility of interactions at these three levels. The heterogeneity of the aging phenotype among individuals of the same species and differences in longevity among species underline the contribution of both genetic and environmental factors in shaping the life span. In this mini review, several theories are identified only briefly; a few (evolutionary, gene regulation, cellular senescence, free radical, and neuro-endocrineimmuno theories) are discussed in more detail, at molecular, cellular, and systemic levels.