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Biomedical subjects

A Sandison

Publications and source records attributed to A Sandison.

5 recordsLinked to original sources

Comparison of size of juxtamedullary and outer cortical glomeruli in normal adult kidney.

Abnormally large glomeruli are susceptible to hyperfiltration-associated sclerosis. We used an established morphometric method to test the general belief that juxtamedullary glomeruli are larger than those in the outer cortex, in a population with no clinical or pathological evidence of renal disease. Overall, juxtamedullary glomeruli were significantly larger, but this varied according to the amount of global glomerulosclerosis present. Global sclerosis increased with age, particularly in the outer cortex, and the ratio of juxtamedullary to outer cortical glomerular size showed a positive correlation with overall, and outer cortical, global sclerosis. Thus in the truly normal adult kidney, juxtamedullary glomeruli are not significantly larger than outer cortical glomeruli. However, global sclerosis increases with age and is most marked in the outer cortex, and this leads to compensatory enlargement of predominantly the juxtamedullary glomeruli. These findings suggest that in single kidneys, or in conditions characterised by ischaemic glomerulosclerosis such as hypertension, morphological changes related to hyperfiltration may appear first, and therefore become most severe, in juxtamedullary glomeruli.

Adult

Evidence for unique distribution of Kimmelstiel-Wilson nodules in glomeruli.

Different distributions of segmental lesions within glomeruli correspond to different pathogenetic mechanisms. A graphic method of analysis of the position of segmental lesions was applied to 106 Kimmelstiel-Wilson nodules in 10 renal biopsies from patients with diabetic glomerulonephropathy, 4 with IDDM and 6 with NIDDM. The nodules were randomly distributed in a horseshoe-shaped area corresponding to the peripheral or intralobular mesangium. This distribution was different from that of segmental lesions studied previously in the glomerular tip lesion, in vasculitic-type glomerulonephritis, and in hyperfiltration associated with reduced renal mass. Our finding is consistent with ideas that Kimmelstiel-Wilson nodules have a distinct pathogenesis not related to hyperfiltration or any other process previously investigated as a cause of characteristic distribution of segmental lesions.

Adult

The alpha and pi isoenzymes of glutathione S-transferase in human fetal lung: in utero ontogeny compared with differentiation in lung organ culture.

Polyclonal antisera to the alpha and pi isoenzymes of glutathione S-transferase have been used in immunohistochemical studies of developing human lung. In utero expression of the pi set was down-regulated in distal airway cells and the first appearance of pi-negative cells coincided with phenotypic differentiation. In contrast, in the early phase of fetal lung organ culture pi isoenzyme was detected in all differentiated epithelial cells and only as culture progressed did focal negativity develop. The alpha set showed no developmental changes in utero or in organ culture.

Down-Regulation

Development of the cerebellum with particular reference to cellular differentiation in the external granular layer.

Immunocytochemical evidence of differentiation in developing human cerebellum is presented in this study. Antibodies to neuron specific enolase, neurofilament protein, glial fibrillary acidic protein, vimentin, cytokeratin, epithelial membrane antigen and lymphoid markers, DLC and Leu 7 were used. The external granular layer showed positivity with neuronal markers between 27 weeks gestation and 4 months postnatal, but was negative for all other markers including glial fibrillary acidic protein. Characteristic staining reactions were noted in the other cerebellar layers. Monoclonal antibodies, UJ13A (pan-neuroectodermal marker) and G10 (localising microtubule-associated protein MAP1x) were also used in a limited number of cryostat sections and were positive and negative, respectively, in the external granular layer. The results of this study are discussed in relation to the theory that the external granular layer may be one source of medulloblastomas.

Biomarkers