Renal hemosiderosis due to thalassemia: a light and electron microscopy study with electron probe X-ray microanalysis.

A kidney biopsy specimen with pronounced hemosiderosis from a patient with beta-thalassemia major was studied by light and electron microscopy, including X-ray microanalysis. Ferritin was absorbed from the glomerular ultrafiltrate through the parietal epithelial cells and the tubular epithelial cells and from the blood through the endothelial cells. It was transported in siderosomes into the surrounding basal lamina, where electron-dense deposits of hemosiderin were found in the outer part of the lamina densa and the reticular lamina. Fibrosis was seen as a reaction to the iron followed by severe atrophy of affected structures.

Fine structure of camel erythrocytes in relation to its functions.

The fine structure of the red cells in Arabian camels was investigated and certain characteristic features were noted. The plasmalemma of camel erythrocytes are tri-laminar, the inner and outer membranes are of high electron density between which is a zone of lesser electron density. No intracellular organelles were observed with the occasional exception of a small number of mitochondria. In the camel erythrocyte, a marginal band consisting of 30-45 microtubules was observed in many cells. Some of the possible functions of the marginal band in camel erythrocytes are discussed.

Ultrastructure of camel basophilic granulocytes with special reference to its functions.

The ultrastructure of camel basophils in peripheral circulating blood of the Arabian camel were studied in order to provide detailed description of its constituents. Camel basophils were found to possess pseudopodia of varying lengths and numbers. Electron micrographs of camel basophilic granulocytes reveal that the cytoplasm is of moderately electron density. Membrane bound granules of different sizes and varying electron density, spherical or oval in shape, were observed, vacuoles of various forms, a well-defined Golgi complex, few rough endoplasmic reticulum and mitochondria were noticed randomly distributed in the cytoplasm. The results obtained were compared with that reported for other mammalian species and interpretation of the functional activities of the basophil intracellular organelles were discussed.

Ultrastructure of the camel monocyte.

The fine structure of the camel monocytes was studied in order to record its constituents because these informations were missed from the literature. The observations revealed the presence of a few short cisternae of rough endoplasmic reticulum and various forms of vesicles associated with the Golgi complex which were seen near the mitochondria. The distribution of the cytoplasmic organelles seemed to be located adjacent to the main indentation in the nuclei. Camel monocytes were found to possess microvilli of varying length and number. The functional morphology of the above mentioned structures was discussed.

Fine structure of the camel neutrophilic granulocytes with special references to its function.

This study is directed at the population of neutrophilic granulocytes in the peripheral circulating blood of the one-humped camel. The detailed fine structure is described and a number of cellular parameters are determined. Particular attention was given to the characteristics of the cytoplasmic granules of this cell type. The functional roles of these intracellular granules are discussed.

Possible use of an indicator muscle in future breeding experiments in domestic fowl.

Domestic fowl were chosen for different body weights in descending order of size, viz. Tetra, Rhode Island Red/Light Sussex cross, White Leghorn and Bantam. The numbers and sizes of fibres in various muscles were determined by quantitative histology, and fibre number was also estimated by DNA measurement. In contrast to the situation in mammals, fibre size (diameter) was of greater importance than fibre number in determining muscle size. Biochemical measurement of DNA content in a muscle was not a reliable estimate of cell number without histological verification. It is suggested that the anterior latissimus dorsi muscle could be used as an indicator muscle in future selective breeding programmes for fibre number because of its fibre arrangement and accessibility.

Differentiation of muscle and the determination of ultimate tissue size.

The factors that determine ultimate muscle size have been studied using a "model" that involves two strains of mice, which had been especially bred for "largeness" (QL) and for "smallness" (QS). The difference in muscle size was not found to be due to a difference in fibre size, but due to a difference in fibre number. The muscles from the "QL" mice contained about 30% more fibres. The reason for this increased fibre number was investigated. During early development, the fusion of mononucleated presumptive myoblasts to form multinucleated myotubes took place at the same time in both "QL" and "OS" mice, as indicated by the appearance and increase in activity of ATP: creatine phosphotransferase. At this stage fibre (and cell) number and size could be determined by measuring nuclear number and protein/DNA ratio respectively. No difference in fibre (and cell) size could be found in mice at 5 days before birth, newly born, or at 20 days of age. At these ages it was found that the muscles from the "QL" mice contained a greater number of nuclei (muscle cells). The amount of RNA/nucleus was used as an index of protein synthetic rate, and no difference could be found between the large mice and the small mice. It was concluded that, in the case of the "QL" mice, the increased fibre number was not brought about by: (i) a delay in time of fusion of presumptive myoblasts; (ii) a smaller number of myoblasts fusing to form myotubes; or (iii) extensive fibre formation after fusion. Differences in fibre number, and hence muscle size, must therefore, presumably be caused by initial differences in the rate of proliferation of myoblasts before fusion.