Midwest wrestling study: prediction of minimal weight for high school wrestlers.

This study determined the validity of previously published or newly derived equations to predict fat-free body mass (FFB) in high school wrestlers from the midwestern United States. Five laboratories participated in the data-pooling study (total sample of 860 subjects). Measures included body composition by underwater weighing and anthropometric measurements of body mass, stature, and selected circumferences, diameters, and skinfolds. Cross-validation of selected equations to predict FFB revealed the lowest levels of error from the equations of Lohman, Thorland et al., Katch and McArdle, and Behnke and Wilmore. Modification of the constants in these equations or generation of new equations did not substantially reduce prediction error. Overall, total error for these top equations ranged from 2.44 to 2.59 kg. However, based on observed trends, this error was of lower magnitude with the younger and lighter subjects and of higher magnitude with the older and heavier subjects. We conclude that these equations could be used singularly or collectively to determine FFB, and a minimal weight could then be derived and assigned to a scholastic wrestler.

Studies of the ocular compatibility of hydrogels. White spot deposits--chemical composition and geological arrangement of components.

Light, SEM and histochemical techniques were used to determine the architecture and composition of elevated deposits on a variety of commercial lenses of differing bulk and surface chemistries and wear protocols. Spoilt lenses were derived from controlled lens wear trials and additional clinical sources. Elevated deposits display a complex multilayered structure, unaffected by variations in wear protocol or bulk and surface chemistries. These deposits are predominantly composed of tear-derived lipids laid down in a well-defined fashion. The primary layer is composed of unsaturated lipids, whilst the secondary and tertiary layers are dominated by cholesterol and cholesterol esters. The composition and location of deposit components is unaffected by variations in, wear protocol, chemistry of the lens matrix, or tear composition of lens wearers. These findings suggest that unsaturated lipids are responsible for the biological interfacial conversion of hydrogel lenses, reducing their compatibility with the ocular environment.

Studies of the ocular compatibility of hydrogels. A review of the clinical manifestations of spoilation.

The range and nature of the various clinical manifestations of hydrogel contact lens spoilations are considered. An indication of the present view of the occurrence, chemical composition and potential aetiology for discrete elevated deposits, organic and inorganic surface films, plaques and granular deposits, microbial spoilation, lens discoloration and other extrinsic factors is provided. The literature is principally concerned with the clinical manifestations of spoilation and most observations have been made on lenses that have become so severely spoiled as to be unwearable. No serious attempt has yet been made to identify those tear species responsible for the development of the various types of deposits or of the effects of variations in the bulk and lens chemistry, and also wear protocols on the formation of deposits.

Studies of the ocular compatibility of hydrogels. White spot deposits--incidence of occurrence, location and gross morphology.

Light and scanning electron microscopical techniques have been employed to determine the morphology, geographical location and incidence of occurrence of discrete elevated deposits on a variety of commercial lenses of differing bulk and surface chemistries and also wear protocols. Spoilt lenses were derived from controlled lens wear trials and additional clinical sources. This type of elevated deposit displays a complex morphology and is composed of three distinctive yet interactive sub-layers. It is apparent that alterations in lens surface properties, wear protocol, and application of the device are not significant in determining deposit morphology. The rate of deposit formation is however, a function of the lens chemistry, wear protocol and the individual patient. These findings promote the belief that some common biological interface conversion event, or events, occur which reduce the biocompatibility of these materials with their ocular environment.