Microcalorimetry of the adsorption of lysozyme onto polymeric substrates.

The conformation of blood proteins adsorbed on biomaterial surfaces probably plays a significant role in the biocompatibility of blood-contacting implants. This paper reports heats of adsorption of a globular protein, lysozyme, onto three uncharged polymeric substrates. Variations in heats among substrates reflect differences in the lysozyme/substrate interaction as well as the possibility of substrate-dependent conformations. In each case, a series of plateaus appeared in the adsorption isotherm with increasing concentration. In the cases of two substrates, polystyrene and poly(styrene-co-butyl methacrylate), endothermic discontinuities appeared at rises between plateaus. It is proposed that the step pattern in each isotherm reflects distinct conformational states of lysozyme on the substrate surfaces. Endothermic discontinuities may be latent heats associated with change to a more stable conformation after initial adsorption. The absence of discontinuities in the case of poly(styrene-co-allyl alcohol) suggests structural transitions occur to a smaller extent on this material and results in conformations different from those which occur when lysozyme is adsorbed by polystyrene or by poly(styrene-co-butyl methacrylate).

Importance of periodontal disease in the kidney patient.

End-stage renal disease (ESRD) patients on hemodialysis experience a greatly increased rate of atherosclerotic complications. In both hemodialysis and general populations, it has become evident that inflammation plays a central role in the pathogenesis of atherosclerotic complications. C-reactive protein (CRP), the major acute phase protein in man, has been found to predict all-cause and cardiovascular mortality in ESRD patients on hemodialysis maintenance therapy. Hepatic CRP synthesis is upregulated by proinflammatory cytokines released locally at sites of infection or inflammation, although many patients experience elevated CRP values in the absence of overt infection or inflammation. Destructive periodontal diseases in the general population have been associated with both an increased prevalence of atherosclerotic complications and an elevation in serum CRP values. In view of the prevalence of destructive periodontal diseases in the general population, and since periodontal evaluations are normally not performed as part of a medical assessment, destructive periodontal diseases may be an over looked source of inflammation in ESRD patients on hemodialysis therapy. The intent of this report is to review the possible role destructive periodontal diseases and associated periodontal infections may play in the management of the ESRD patient on hemodialysis maintenance therapy.

Materiales dentales restauradores

Alcance e historia de los materiales dentales. Propiedades físico-químicas aplicadas. Propiedades ópticas, térmica y electricas. Propiedades mecánicas. Naturaleza de los metales y aleaciones. Polímeros y polimerización. Interacción de los tejidos con los materiales dentales. Cementos. Amalgama. Materiales para restauraciones estéticas directas. Materiales para impresión. Yesos y revestimientos. Ceras. Metales nobles y preciosos. Aleaciones metálicas no nobles coladas y labradas. Procedimientos de colada. Cerámica. Sistemas ceramo-metálicos. Aplicaciones de los polímeros en prótesis. Apéndice

Materiales dentales restauradores

Alcance e historia de los materiales dentales. Propiedades físico-químicas aplicadas. Propiedades ópticas, térmica y electricas. Propiedades mecánicas. Naturaleza de los metales y aleaciones. Polímeros y polimerización. Interacción de los tejidos con los materiales dentales. Cementos. Amalgama. Materiales para restauraciones estéticas directas. Materiales para impresión. Yesos y revestimientos. Ceras. Metales nobles y preciosos. Aleaciones metálicas no nobles coladas y labradas. Procedimientos de colada. Cerámica. Sistemas ceramo-metálicos. Aplicaciones de los polímeros en prótesis. Apéndice

Mouth Protectors in Junior Football Players.

In brief This study tested Sta-Guard and Proform mouth protectors that were worn by 280 football players aged 9 to 12 years. Laboratory studies were also conducted to test tensile and tear strength, dynamic modulus and resilience, and hardness. The players received new mouth guards every two weeks for 12 weeks and reported any problems with gagging, taste, speech, feel, and durability. Ninety percent of the boys preferred the Sta-Guard mouth protector, stating that it was softer, more resilient, and more comfortable than the Proform mouth guard.

Materiales dentales restauradores

Alcance de los materiales restauradores y su historia. Principios fundamentales aplicados. Propiedades físicas y mecánicas. Aplicaciones de la biofísica en materiales. Naturaleza de los metales y aleaciones. Materiales para impresión. Yeso y sus derivados. Ceras. Oro y sus aleaciones. Procedimientos de colado. Aleaciones de metales no nobles. Amalgama. Cementos. Plásticos. Porcelana