A Scanning Electron Microscope Study of the Ultrastructural Organization of Bone Mineral

Scanning electron microscopy (SEM) was used to study samples of lamellar bone at magnifications typical for the published transmission electron micrographs, to gain more insight into the three-dimensional ultrastructure of bone mineral. Untreated (whole bone) samples allowed an assessment of the degree of mineralization. Deproteinized samples revealed the ultrastructural form and organization of bone apatite to be a function of the extent to which collagen fibers were imbibed with mineral. Numerous parallel formations reminiscent of troughs, gutters, or furrows, pierced and traversed the mineralization front. These troughs showed varying diameters identifiable with collagen fibers, and were separated from one another by an elaborate system of thin platy septa and flakes. The troughs were interpreted as impressions of dissolved collagen fibers and bundles. Confluencing calcospherites were characterized by rod-shaped and fusiform mineral aggregates with diameters complying with collagen fibers and bundles. Mature mineral showed no plates; it was characterized by bundles of vermiform particles. It is suggested that in newly deposited bone mineral, mineral aggregates incompletely encrust collagen fibers and bundles, forming perifibrillar and interfibrillar plates and sheaths. During further mineralization these aggregates appears to coalesce to a continuous mineral phase

O'nyong-nyong fever in south-central Uganda, 1996-1997: clinical features and validation of a clinical case definition for surveillance purposes.

O'nyong-nyong (ONN) fever, caused by infection with a mosquito-borne central African alphavirus, is an acute, nonfatal illness characterized by polyarthralgia. During 1996-1997, south-central Uganda experienced the second ONN fever epidemic ever recognized. Among 391 persons interviewed and sampled, 40 cases of confirmed and 21 of presumptive, well-characterized acute, recent, or previous ONN fever were identified through active case-finding efforts or during a household serosurvey and by the application of clinical and laboratory criteria. Among confirmed cases, the knees and ankles were the joints most commonly affected. The median duration of arthralgia was 6 days (range, 2-21 days) and of immobilization was 4 days (range, 1-14 days). In the majority, generalized skin rash was reported, and nearly half had lymphadenopathy, mainly of the cervical region. Viremia was documented in 16 cases, primarily during the first 3 days of illness, and in some of these, body temperature was normal. During this epidemic, the combination of fever, arthralgia, and lymphadenopathy had a specificity of 83% and a sensitivity of 61% in the identification of cases of ONN fever and thus could be useful for surveillance purposes