A classification and quantitative histological study of abnormal ureters in children

Development of elastic fibres in the upper urinary tract

The development of elastic fibres in the upper urinary tract was studied in 31 fetuses ranging in ovulatory age from 10 to 24 weeks using special staining techniques for elastic fibres. The number, orientation and distribution of elastic fibres are described and correlated with age, ureteric level, and fetal weight. Significantly, before 10 weeks, elastic fibres were few in number, poorly developed, and randomly arranged. After 12 weeks, these fibres became more numerous at each level of the urinary tract, and were seen to develop specific orientation. The findings are described and potential clinical implications are discussed.

Elastin and collagen in the normal and obstructed urinary bladder

Histological and chemical studies were carried out on the elastin and collagen content of the normal and the obstructed urinary bladder wall. The observations were made on 3 different age groups: (1) 3-month-old children with vesical outlet obstruction, (2) children aged between 4 and 8 years with partial vesical obstruction, and (3) adults with a chronically obstructed bladder. An increase in elastic tissue was shown only in the newborn and in the adults. The collagen did not vary in any of the cases studied. The elastin showed an increase in polar amino acids in the pathological organs compared with the normal. A similar increase in elastin was observed in normal individuals as a result of the ageing process.

Structural evidence for insertion of collagen fibres to smooth muscle cells in the carotid arterial system of the giraffe (Giraffa camelopardalis)

Previous anatomical studies have failed to resolve the question relating to whether or not collagen fibers, like elastic fibres, are attached to smooth muscle cells in the arterial wall. The current ultrastructural study demonstrates the insertion of collagen fibres to the sarcolemmal dark areas in the smooth muscle cells of the carotid arterial system of the giraffe. It is concluded, therefore, that this morphological linkage between collagen and smooth muscle cells may facilitate transmission of the force of contraction between the cells and to the surrounding connective tissue framework since the myofilaments appear to be spatially placed in series with the extracellular collagen fibres at the sarcolemmal dark areas.

The elastic tissue of the adult dilated ureter

Adult dilated ureters have been examined in order to calculate the amount of the elastic tissue. From the histological observations and by the chemical analyses performed on the extracted elastin a decrease of the elastic tissue, as compared to the normal adult ureters has been noted. In fact, in the adult normal ureters, the elastin accounts for 9% of the dry matter, while in the abnormal the elastin represents 6.5%.

The elastic component of normal and dilated ureters in children: chemical and histochemical characterisation

Using chemical and histochemical techniques, it has been possible to calculate the exact amount and distribution of the elastin in normal and abnormal ureters in children. From the quantitative analyses, it has been calculated that in the dilated ureters the elastin content represents the 3% to 5% of the organic material, while in the normal ureters it is less than 1%.