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Biomedical subjects

G L Panattoni

Publications and source records attributed to G L Panattoni.

At least 19 recordsLinked to original sources
PubMed1995

Densitometric study of developing vertebral bodies.

To define the quantitative aspects of ossification of human fetal spine, we performed a high resolution densitometric study by lateral and postero-anterior scanning of five fetal spines (18-36 weeks of conceptual age) and one spine of a 4-month-old infant. The data were plotted against developmental age for each spine and vertebra. Bone mineral content increased with developmental age, with a peak at the upper lumbar level, in agreement with the ossification pattern of the spine, reported in embryological literature. Bone mineral density (BMD) was unrelated to developmental age, and showed similar trends for each vertebra in all the vertebral columns examined. The changes of BMD seems to be a phenomenon related to individual variability. This study also demonstrates that densitometric techniques may provide useful and interesting information in studies on skeletal development.

Absorptiometry, Photon↗
PubMed1995

Ontogeny of calbindin-D28K and calretinin in developing chick kidney.

The ontogeny of two calcium-binding proteins (calbindin-D28k and calretinin) was studied by immunohistochemical techniques in developing chick kidney. This study showed the presence of calbindin on the 5th incubation day and calretinin on the 7th incubation day in mesonephric distal and connecting tubules, and in the medial wall of the Wolffian duct. At later stages, immunostaining for these two proteins, in particular for calretinin, was also demonstrated in some metanephric proximal tubules. Glomeruli and Bowman's capsules were negative both in the mesonephros and metanephros. The presence of calretinin in the developing kidney has thus been demonstrated for the first time. The early expression of calbindin and calretinin in mesonephric distal tubules suggests their role in regulating the final excretion of calcium. The different patterns of immunoreactivity of the walls of the Wolffian duct can be correlated with their different histogenetic and histological features.

Animals↗
PubMed1995

Notochord degeneration in chick embryo: a particular case of developmental cell death?

To define the type of cell death occurring in notochordal tissue, the cytological features of degenerating notochord were studied by transmission electron-microscope in thirty chick embryos from the 20th hour to the 15th incubation day. During the first two days the notochordal cells show nuclei with large nucleoli and cytoplasm with yolk granules, lipid droplets, phagolysosomes and deposits of glycogen. From the 3rd to the 5th incubation day, besides the peculiar vacuolization, disaggregation of the endoplasmic reticulum, transformation of the mitochondrial morphology, and disintegration of the cell membrane are detectable. Nuclei are normal up to advanced stages of cytoplasmic degeneration. On the 6th day a large number of cells are dying and, later on, the tissue disintegrates at the level of the vertebral bodies. Cell death in the notochord does not seem to be classifiable as one of the types of developmental cell death described in literature: the comparison with similar cytological features referred by pathologists as a consequence of metabolic damage, suggests that the degeneration of the notochord may be related to its morphological isolation and thus to trophic deprivation.

Animals↗
PubMed1993

"Chordoid tissue": biological significance and relevance of the term.

The significance and relevance of the term "chordoid tissue" are discussed on the ground of some ultrastructural features of the notochordal cells, observed in 15 chick embryos from stage 5HH to hatching. The characteristics of the cytoplasmic organelles and of the nucleus, the membrane alterations and in particular the vacuolization show the notochordal cells undergo a process of necrobiosis rather than of apoptosis. The degeneration of the notochord, that not casually starts in the notochordal core, seems to be due to a progressive metabolic isolation, related to the lack of blood vessels and to the formation of a thick perichordal sheath. These findings suggest that the notochordal tissue shows the same cytologic features of any tissue degenerating owing to a metabolic damage. The term "chordoid tissue", in the meaning of a tissue with peculiar structure and function, does not seem hence to be relevant, also on the ground of the fact that in the species in which a nucleous pulposus arises from notochord remnants, the notochordal cells show the same ultrastructural characteristics detectable in chick embryos.

Animals↗
PubMed1993

Expression of calcium binding proteins in the developing spine: preliminary report.

Previous ultrastructural studies on the developing spine induced the Authors to analyse the presence of Ca-binding proteins in the vertebral anlagen of the chick embryo, by immunostaining for calretinin. At 7 incubation days, intense positivity for calretinin at level of the intervertebral region is detectable. From the 7th day the positivity is localized in particular to the intervertebral menisci and it appears also in the degenerating chondrocytes of the chondrifying vertebrae and at level of the peripheral zones of vascular erosion in the ossifying vertebrae. The intervertebral positivity for calretinin can be related to the presence at this level of fibroblast-like cells, that for such immunoreactivity are distinguishable from true fibroblasts. Since other Authors showed presence of S-100 protein in fibroblast-like cells during histogenesis of white adipose tissue, the significance of the expression of some Ca-binding proteins in the differentiation of these cell types can be supposed. The meaning of the immunoreactivity in the vertebral bodies is still uncertain and needs further immunohistochemical studies.

Animals↗
PubMed1993

Cytodifferentiation of the notochord in early chick embryo related to the development of the axial and paraxial structures.

The cytology of the notochord was investigated by means of L.M. and T.E.M. in fifty chick embryos from the 7th HH stage to hatching, at different levels of the longitudinal axis and at different levels in each somite. The cytodifferentiation of the notochord was compared with the one of the surrounding axial and paraxial structures (neuro-epithelium and somites). Close segmental relations among notochord, neural groove and sclerotome, i.e. reciprocal contacts of cell processes and filopodia, where observed in 7-9 HH stages embryos. During the following stages in the notochordal cells signs of secretory activity are detectable, but at the same time degenerative changes are evident and they will increase up to the total regression of the notochord. These morphological observations seem to suggest the presence of reciprocal morphogenetic influences among notochord, neuro-epithelium and sclerotome, only before the 9th stage, rather than a determinant role of the notochord in the surrounding structures at later developmental stages.

Animals↗
PubMed1991

Chondrogenic gradients in the developing vertebral body.

Since in literature the question of the spatio-temporal sequence of the cartilage maturation in the developing vertebra is still controversial, the authors studied by light and electron microscope, the chondrification of the vertebral body in chick embryo from the 6th to the 13th incubation days, in order to define the correlations between morphology and distribution of the cartilage cells in this phase of vertebral development. The results show that the chondrogenesis follows spatio-temporal gradients, starting at about the 8th incubation day from a zone located between notochord and neural tube, slightly cranially to the midvertebral level. From this starting point the chondrification proceeds with dorso-lateral and radial progression, and at the same time extends towards the cranial and caudal plates of the developing vertebra. These data are compared to the findings obtained by other authors on the ultrastructural and biochemical aspects of the vertebral development.

Animals↗
PubMed1979

A developmental model for studying choline acetyltransferase transport in chick motoneurons.

The proximodistal axonal transport of choline acetyltransferase (ChAc) has been studied in the chick sciatic nerve in the absence of any experimental manipulation. The phenomenon utilized by us is a physiological transient fall in the activity of ChAc. This fall occurs in most areas of the chick central nervous system after hatching, and moves toward the periphery along the nerves. Having ruled out the presence of transient inhibitors, the movement of the fall towards skeletal muscles has been considered to correspond to the proximodistal transport of ChAc. The calculated average velocity is 7.86 mm/day, corresponding to the slow rate of transport. Nevertheless, the kinematics study suggests that the velocity varies along the nerve from a state of rest to an intermediate rate of transport (16 mm/day). The possible influence of variations in the resistance of the conductor on these changes in velocity is discussed.

Aging↗