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G Filogamo

Publications and source records attributed to G Filogamo.

At least 19 recordsLinked to original sources
PubMed1995

Ontogenesis of the structural elements of the heart.

A review of the birth locus and the first developmental stages of cardiomyocytes and Purkinje cells in the chick embryo is presented in the light of recent experimental results. Experiments done in vitro have shown that the stage of 2 somites is an important morphogenetic phase, characterized by mutual identification, selective adhesion and spatial organization of the putative cardiac cells of the splanchnopleural sheet in the cardiogenic area. Many experimental data suggest that the neural crest cells moving through the corridor of the dorsal mesocardium, as well as the cholinergic system related to them, may play a role of myogenic inductors on the mesothelial putative cardiac cells. In addition, other experimental findings suggest that the Purkinje cells of the conduction system may have a crestal origin. This hypothesis is well grounded, although the origin of Purkinje cells remains to be clarified.

Animals↗
PubMed1994

Quantitative study of the NADPH-diaphorase-positive myenteric neurons of the rat ileum.

The subpopulation of myenteric neurons able to synthesize nitric oxide was studied quantitatively in the adult rat, using the NADPH-diaphorase histochemical method on whole-mount preparations of distended distal ileum. The spatial density of NADPH-diaphorase-positive myenteric neurons was 2388 +/- 193/cm2 (S.D.; five rats), comprising about 27% of the nerve cell bodies per ganglion. Most neurons were intensely stained and displayed predominantly a Dogiel type I morphology; about 8% of the labelled nerve cells were ovoid neurons, exhibiting a pale cytoplasmic reaction product. The mean somatic size of all NADPH-diaphorase-positive myenteric neurons was 446 +/- 40 microns2, with a mean nuclear size of 96 +/- 18 microns2 (mean values +/- S.D.; five rats). Such values fell exactly within the range of neuronal sizes of the total myenteric population, marked by means of NADH-diaphorase histochemistry. Therefore, the morphometric analysis did not identify any peculiar cell size feature, characterizing this specific nerve cell subpopulation. Thus, the present study provides quantitative data on the size, density and proportion of those myenteric neurons that may synthesize nitric oxide in the distal ileum of the rat.

Animals↗
PubMed1992

Comparative study of Langerhans cells in normal and pathological human scars. I. Atrophic scars.

In the present study, we investigated Langerhans cells (LCs) in the epidermal component of human atrophic scars, comparing them with those in control skin and normotrophic scars. A preliminary analysis of the histological features was first carried out on vertical serial sections, stained with hematoxylin and eosin. The total epidermal thickness and the thickness of the single epidermal layers were then measured, by means of a digitizing tablet and a morphometric program run on an Apple IIe computer. These parameters were found to be significantly lower (40%) in atrophic scars, if compared to control skin and normotrophic scars (p less than 0.05). CDla-positive and HLA-DR-positive LCs were marked by indirect immunofluorescence. Their position among the epidermal layers, their dimensions, their density and their morphology were examined. In atrophic scars, LCs were densely and evenly distributed in all the epidermal layers. Their density was increased (about 1200 cells/mm2 of epidermal area), if compared to control skin and normotrophic scars (both 300-400 cells/mm2 of epidermal area; p less than 0.001). The CDla-positive definite cell bodies, exhibiting an unstained nucleus, were as large as those evidentiated in the normotrophic scars and twice as much the control skin values (p less than 0.001). The present results provide morphological data that distinguish atrophic scars from control skin and normotrophic scars, and suggest an involvement of the Langerhans cells in this particular case of pathological scarring.

Adolescent↗
PubMed1992

Comparative study of Langerhans cells in normal and pathological human scars. II. Hypertrophic scars.

Langerhans cells (LCs) seem to play a crucial role in the immune system of the skin. Changes in their density, distribution, phenotype and/or morphology have been described in a number of skin diseases, mostly immunologically mediated. For this reason, we investigated LCs in human hypertrophic scars, since these scars are presently believed to have an immunological basis. A preliminary analysis of the histological features was carried out on vertical serial sections, stained with hematoxylin and eosin. Both epidermal and dermal components of hypertrophic scar biopsies were examined. The total epidermal thickness and the thickness of the single epidermal layers were also measured; the values obtained were similar to those of control skin and normotrophic scars. Subsequently, CDla-positive LCs, revealed by indirect immunofluorescence and immunoperoxidase techniques, were studied to determine their position among the epidermal layers and within the dermis, their dimensions, their density and their morphology. According to these observations, two main types of hypertrophic scars were identified. In the first type (7 scars), LCs were widely clustered within both the whole epidermis and the dermis. Their density was increased (about 750 cells/mm2 of epidermal area), if compared to control skin and normotrophic scars (both about 400 cells/mm2 of epidermal area; p less than 0.001). The epidermal cell profiles, nearly three times larger than those of control skin, exhibited a dense network of interconnected dendrites. Further analysis for the presence of HLA-DR molecules revealed an anomalous expression of these antigens on keratinocytes. In the second type (3 scars), LCs density within the stratum Malpighii was unchanged, relative to control skin and normal scars, while CDla-positive cell bodies remained numerous in basal position and within the subpapillary corion. Epidermal LCs, only slightly larger than those evidentiated in control skin, displayed short and retracted dendritic projections. The aberrant expression of HLA-DR antigens on keratinocytes was very weak and sparse. The present results strongly suggest an immunologically activated state of the tissues examined; they provide morphological data that support the involvement of the immune system in hypertrophic scarring.

Adult↗
PubMed1990

Differentiation of cardiac conducting cells from the neural crest.

Some of the cells that migrate to the dorsal myocardium of the chick embryo in stage 21 H-H begin to synthesize desmin. They retain this property even when they reach the subendothelial layers of the heart bud, i.e. the characteristic site of the cardiac conducting cells.

Animals↗
PubMed1990

Embryogenesis of the avian iris sphincter muscle: in vivo and in vitro studies.

The histogenesis of iris sphincter muscle was studied in birds. Chick embryo iris "anlagen", ages from 3 days (st. 18 H.H.) to hatching, were examined. At the 4th day (st. 24 H.H.), nerve fibers were observed in the mesenchyme of the inferotemporal quadrant of the optic cup near the colobomic fissue. Among the mesenchymal cells, there were cells characterized by AChE activity, presence of desmin filaments, exhibiting ACh receptors, and ultrastructurally similar to the presumptive skeletal myoblasts. One day later (st. 27 H.H.), these myoblasts could be cultivated. The formation of myotubes began between 10 and 12 days. From 9 to 14 days, cells left the anterior epithelium of the iris to give rise to the smooth iris muscle; during this evolution some epithelial cells fused with the myotubes taking part in the histogenesis of striated muscle. The possibility of a neurogenic determination for the iris skeletal muscle is discussed.

Animals↗
PubMed1989

Dynamics of soleplate formation.

Immunohistochemical techniques with anti-desmin, anti-acetylcholine receptor and anti-fibronectin antisera and autohistoradiography were used to determine the dynamics of neuromuscular synaptogenesis. Fast twitching muscles were taken from chick embryos at 5 to 14 days of incubation. "Primitive eminences" at terminal arborizations of motor neurons were composed of Karnowsky positive, anti-desmin and anti-acetylcholine receptor positive cells which contained sites bound to alpha-bungarotoxin. These cells, characterized as myoblasts, fused with the myotubes during formation of neuromuscular junctions in the sites of contact with terminal arborizations of motor neurons. Their nuclei and cytoplasmic organelles become the nuclei and organelles in the soleplate.

Animals↗
PubMed1988

Histochemical, immunohistochemical, and ultrastructural observations on the iris muscles of Gallus gallus.

The distribution and typology of fibers in the two muscular systems (sphincter and dilator) of the iris in Gallus gallus were determined histochemically, immunohistochemically, and ultrastructurally. The sphincter muscle in proximity to the ciliary margin was composed predominantly of slow fibers. In the intermediate tract, a large group of fast oxidative fibers were evident and the pupillary margin was exclusively composed of slow fibers. The fast fibers had histochemical and immunohistochemical patterns similar to the alpha fibers in the skeletal control muscle (biventer cervicis). In contrast, the slow fibers were composed of at least three slow types, which were comparable to the isoforms of the different myosins in beta 1 and beta 2 skeletal fibers. In the dilator muscle, the oblique system was uniquely composed of fast oxidative fibers. The radial system was predominantly composed of slow fibers with isoforms of myosins different from the slow fibers of the sphincter and control muscles. Ultrastructural features (width of Z bands, extension of the sarcoplasmic reticulum and SR-T tubule junctions, and number of mitochondria) confirm the histochemical and immunohistochemical assessments of fiber types, even if some peculiar aspects in several fibers were observed. Smooth muscle cells separated from striated fibers were evident at the pupillary margin. The hypothesis of a mesenchymal origin for all irideal striated muscles is discussed.

Animals↗
PubMed1988

DNA content in neurons of Auerbach's plexus under experimental conditions in adult rats.

Some nerve cells of the Auerbach's myenteric plexus of the intestine of the adult rat, which hypertrophied following a surgically induced stenosis, began DNA synthesis unrelated to mitotic division. The cytophotometric analysis confirmed and quantified the amount of synthesis revealed by autoradiography with tritiated thymidine uptake. Numerous nerve cells show a DNA content exceeding the diploid level. Only a few of these show twice the diploid content. The significance of the DNA synthesis is discussed.

Animals↗
PubMed1988

Origin of the iris sphincter muscle in chick embryo.

The origin of the iridial sphincter muscle in chick embryo was investigated by means of immunohistochemistry. Desmin immunoreactive cells are shown in the mesenchymal stroma overlying the anterior epithelial layer of the iris in 4 1/2-day chick embryos. In 9-11-day chick embryos also some cells of the posterior epithelium near the pupillary margin, and of the iridial lamella show a slighter desmin-immunoreactivity. This finding agrees with a double origin of the iridial sphincter muscle: an early mesenchymal one and a later epithelial other.

Animals↗
PubMed1987

Early myoblast differentiation in fast and slow types.

Serial sections of stage 18-27 HH (3-5 days of incubation) chick embryo myotomes were investigated by electron microscope. Two morphologically different types of contractile elements (myoblasts and myotubes) with an exact and constant localization were identified. Myotome sections of other chick embryos in the same stages were examined with the immunofluorescence technique, after treatment with antisera directed against fast and slow adult myosins. As from stage 24 HH, some contractile elements react positively with anti-fast adult myosin antiserum, others with anti-slow antiserum. A very precise correspondence was constantly found between the ultrastructural and immunohistochemical findings. An identical pattern was observed in the buds of the fast-twitching pectoralis major and posterior latissimus dorsi and slow-twitching anterior latissimus dorsi muscles.

Age Factors↗
PubMed1985

[Does mechanical tension regulate the development of muscular rudiments?].

Following destruction of the right anterior member bud on four-day old chick embryos, a study was made of right and left pectoral muscle growth on serial sections stained by ordinary methods. Certain regions were also examined in the electron microscope. Mitotic activity was studied autoradiographically following the injection of thymidine. Early, frank changes in the pectoral muscle on the amputation side were connected with growth, differentiation and organogenesis: regressive processes were also observed.

Animals↗
PubMed1984

[Acetylcholine receptors in chick embryo somites].

Autoradiography was used to demonstrate the presence of alpha-bungarotoxin binding sites in the medial wall cells of thoracic somites from 44th hr incubation chick embryos. It is suggested that these cells are presumptive myoblasts about to migrate to form the myotome.

Animals↗
PubMed1984

[Contralateral effects of limb removal in the chick embryo].

The bud of the right posterior limb was removed from 4 to 6 days old chick embryos, followed by removal of the muscles of the left posterior limb, with the sciatic nerve and the lumbosacral spinal marrow on the 17th day. ChAc and AChE activities were measured on the amputation side (spinal marrow), on the contralateral side (spinal marrow, nerve and muscles), and in control embryos. There was a significant fall in both activities on the contralateral side, particularly when amputation had taken place on the 4th day. It was also noted that the myelinic fibres of the anterior root on the contralateral side were more numerous than in the control embryos, and that the muscle fibres had a different appearance.

Acetylcholinesterase↗