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Biomedical subjects

G Marotti

Publications and source records attributed to G Marotti.

At least 37 records · Page 2Linked to original sources
PubMed1984

Mechanisms of bone resorption in calcium-deficient rats.

A study of surface remodeling activity and osteocyte lacunar area was made in young and adult rats maintained on a low-calcium diet, to explore cellular mechanisms of bone resorption. The diet produced active remodeling of the endosteal part of the femoral cortex, with a decrease in the amount of bone present. Surface resorption, with numerous osteoclasts, was evident, but there was no evidence of osteocytic osteolysis in bone which, by tetracycline labeling, could be identified as existing at the commencement of the experimental period. Osteocyte lacunae in bone formed during the period of calcium deprivation were somewhat larger than lacunae in control animals, apparently because of interference with the formation or maturation of the perilacunar tissue.

Age Factors↗
PubMed1982

Activity of osteoclasts and osteocytes in compact human bone at various ages, both with and without osteoporosis.

As part of a programme of research designed to assess the respective roles of osteoclasts and osteocytes in the processes of bone resorption, the metabolic activity of these cells was evaluated indirectly by a morphometric method in the compact bone of human tibias from subjects of various ages, both normal and those affected by osteoporosis. Statistical analysis of the quantitative data was in agreement with the microradiographic examination of the sections, and showed that whereas the intensity of osteoclastic resorption varied in the various subjects according to age, periosteocytic osteolysis--in the classical sense of a phenomenon involving widening of the lacunae detectable with the optical microscope--did not occur in compact bone whether it was normal or highly porotic.

Adult↗
PubMed1980

Changes in the vascular network during the formation of Haversian systems.

The pattern of the cortical vascular network and the changes occurring in it during the formation of Haversian systems have been studied in the diaphyses of the tibiae of dogs of various ages. The number, area, perimeter and microscopic structure of the vessels have been investigated with respect to the size of the Haversian canals and length of the osteoblastic layer, using India ink perfusion of the vascular network. The vascular network in compact bone undergoes conspicuous changes as a result of bone growth and turnover processes. The vessels proliferate during the formation of resorption cavities, eventually forming small plexuses of capillaries and tortuous venules. As osteons are laid down and their canals become more narrow, the progressive disappearance of the largest vessels leads to a reduction in the number of vessels in each canal. Morphometric analysis reveals a close correlation between the rate of osteonic bone deposition, the size of osteoblasts and the surface area of the vessels.

Animals↗
PubMed1975

Appositional growth rate in the spongiosa of unloaded long bones of the dog.

In agreement with the results of previous investigations on the dynamics of diaphyseal osteonic bone in inert skeletal segments, it has been observed that the linear appositional growth rate on the trabecular bone of metaphyses and epiphyses does not significantly change in unloaded bones, in comparison with normally loaded ones. Only during the initial period of unloading, a moderate decrement of the aforesaid parameter seems to take place. These findings are briefly discussed in connection with the role presumably played by mechanical stresses on the processes of bone reconstruction.

Animals↗