Drusen prevalence and pigmentary changes in Caucasians aged 18-54 years.

AIMS AND PURPOSE: The aim of this study was to describe the prevalence and characteristics of drusen and pigmentary changes in a middle-aged population. METHODS: Retinal images from 500 individuals aged 18-54 years were included. The source of participants was two UK optometry practices. Retinal images were graded using the Wisconsin Age-Related Maculopathy Grading System. However, owing to the relatively young age of the population studied, a new category of drusen of smaller size (<31.5 µm) was introduced. RESULTS: Drusen were identified within the central macular grid in 91.48% of all gradable eyes and in 444 subjects. Drusen sized <31.5 µm were present in 89.7% of eyes, drusen sized >31.5 µm and <63 µm were present in 45.9% of all eyes and drusen >63 µm and <125 µm were present in only 1.7% of eyes. No eye had drusen larger or equal to 125 µm. Very few eyes (1.2%) showed pigmentary changes within the grid. Drusen load increased with increasing age, P <0.001. CONCLUSIONS: The frequency of drusen in a younger Caucasian population aged 18-54 years is high, with 91.48% of all gradable eyes having drusen. The most frequent drusen subtype was hard distinct drusen <31.5 µm. No druse greater or equal in size to 125 µm was seen. Pigmentary changes are rare.

Two functional O-polysaccharide polymerase wzy (rfc) genes are present in the rfb gene cluster of Group E1 Salmonella enterica serovar Anatum.

Defined regions of the rfb gene cluster of Group E1 Salmonella enterica serovar Anatum were introduced into a mutated derivative of this strain that lacks O-polysaccharide polymerase activity. Three different kinds of assays performed on the various transformants all indicate that two functional wzy (rfc) genes reside within the Group E1 Salmonella rfb gene cluster. The product of ORF9.6, positioned near the center of the rfb gene cluster, joins O-polysaccharide repeat units together by alpha-glycosidic linkages to produce antigen O10, the major serological determinant of Group E1 S. enterica. The product of ORF17.4, positioned at the downstream end of the rfb gene cluster, can join repeat units together by beta-glycosidic linkages to produce antigen O15, the major serological determinant of Group E2 S. enterica.

Retrospective evaluation of osseointegrated implants for treatment of partial and full edentulism at Walter Reed Army Medical Center: Part I: Patient recall.

A retrospective study was done on patients treated with dental implants at Walter Reed Army Medical Center. An extensive recall of patients treated was accomplished. Each patient was clinically evaluated, radiographs were made, and the patients were asked to complete a survey. The results were not statistically analyzed but are reported simply as raw data.

A comprehensive study of physical parameters, biomechanical properties, and statistical correlations of iliac crest bone wedges used in spinal fusion surgery. IV. Effect of gamma irradiation on mechanical and material properties.

The effects of gamma irradiation on mechanical and material properties of iliac crest wedges used in spinal fusion surgery were studied using uniaxial compression testing. The irradiated iliac crest wedges were exposed to 2-2.5 mrad as fresh-frozen and freeze-dried tissues. There were no significant differences in mechanical or material properties of the iliac crest wedges exposed to dosages of 2-2.5 mrad when compared to the nonirradiated wedges. It is suggested that 2-2.5 mrad is an acceptable dose for gamma irradiation sterilization of iliac crest wedges used in spinal fusion surgery and that these tissues may be treated at either the preprocessing or postprocessing stage of wedge production.