Haemoglobin SC disease in Jamaica

A skeletal survey was carried out on 84 cases of haemoglobin SC disease. The radiological features noted were increased translucency of bone, abnormal trabecular pattern, medullary expansion, wide vascular channels in phalanges, and radiological evidence of infarction, both medullary and cortical. The frequency of bone lesions thus demonstrated increased with age. The most characteristic lesions in this region were those of vascular necrosis; contributing factors such as the high haemoglobin level characteristic of the condition are discussed. An interesting feature was the lack of correlation betweeen clinical severity and degree of radiological change. (AU)

Sickle cell beta thalassaemia in Jamaica

An analysis of the radiological appearances in a skeletal survey of 48 patients in Jamaica with sickle cell beta thalassaemia is presented. The appearances are similar to those in homozygous sickle cell disease and SC disease and a confident distinction between the conditions on radiological grounds alone is likely. (AU)

Bone histological changes occurring after haemodialysis treatment for chronic renal failure

The changes that occurred in the histological appearances of iliac crest biopsies after haemodialysis for chronic renal failure in 16 patients are described. In the majority there is loss of bone and an increase in resorptive activity that resembles that seen in "disues" osteoporosis. The amount of osteoid present increases in most of the patients and other defects of calcification also make their appearance during the period of dialysis. None of the changes is peculiar to patients treated in this way. The findings are discussed in the light of hypotheses advanced on the condition of "dialysis bone disease".(AU)

Alizarin red in the study of the apposition and resorption of bone

Alizarin red is given intraperitoneally in dosages of 50-200 mg per kg. It stains visibly only one generation of bone. Its deposition is studied in gross specimens and in undecalcified sections, and is controlled by comparison with serial decalcified sections. Apposition of white bone can be followed in relation to red bone on periosteal surfaces (where it presents appearances corresponding to different growth rates), on endosteal surfaces, in osteons, and in the interstitial compaction of cancellous bone. Red surfaces may be sites of deposition, stasis, or resorption. Measurements may be made from red lines, provided microscopic control is available. Removal of red bone implies resorption. It is closely correlated with the presence of osteoclaasts in control sections and with areas of surface pitting grossly. Resorbing surfaces may be precicely delimited by studing a graded series of animals. Whole surfaces or zones of stained bone are seen to drift to other situations, undergoing resorptive dissolution or consolidating anew as they move relative to the newer layers. The usefullness of the dye lies in its simplicity of administration, its ready visibility, and the fact that its persistence in bone enables the fate of areas of bone to be followed over long periods. The preparation of undecalcified sections is a problem common to many other techniques

Wolff's law and the problem of muscle attachment on resorptive surfaces of bone

During the growth of a bone, outer (periosteal) surfaces in many areas undergo normal remodeling processes involving resorptive removal. Attachments of muscles commonly occur on such outer resorptive surfaces.The cortex in these regions grows in an inward direction by bone deposition on endosteal surfaces. In some areas of a bone, a portion of muscle can be inserted onto adepository surface, but other parts of the same muscle may be attached on to an adjacent resorptive surface. It has been generally assumed that the pull of a muscle acts to directly stimulate deposition of new bone, and that attachments of muscle are thereby responsible for determining the gross morphology of a whole bone. In view of the foregoing considerations, a re-evaluation and an expansion of this concept is now needed. Muscle pull, in many regions of a bone, can be associated with normal cortical recession (involving surface resorption) as well as with outward bone deposition. (AU)