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Biomedical subjects

G Filogamo

Publications and source records attributed to G Filogamo.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1981

Neural influences on the primary myocardium.

In the presomitic stage chick embryo filopodia establish contacts between neural groove cells and those of the presumed heart area. A few hours later, neural crest cells run along the interfaces between the mesothelium and the pharyngeal endodermal cells. Evidence of the transformation of mesothelial cells into myoblasts and appearance of a positive Karnovsky reaction for AChE coincides with this dorso-ventral migration. Exploratory nerve fibres, also contact with the crest cells, do not appear at the site of the first para-aortic sympathetic ganglion buds, and up to the mouth of the syplanchnopharyngeal corridor until the 48th-52nd h. An assessment is made of the significance of crest cells, most of which are destined to become postgangliar neurons, as inducers of the cardiac myogenic line. The possibility that the first contact between the neural groove and the presumed heart area may be of decisive influence, however, is no discarded.

Animals↗
PubMed1980

[Sites of synthesis of acetylcholine receptors in denervated muscles].

Muscle fibres binding with 125I alpha-bungarotoxine from Bungarus Multicinctus, after treatment with saponine, shows (in electron microscope autoradiography) intracellular binding sites identifying sites of acetylcholine receptor synthesis. In innervated muscle, the acetylcholine receptor is located only at the neuromuscular junction. In denervated muscle the receptor is distributed along the whole sarcolemma; in this situation the acetylcholine receptor is synthesized "ex novo" in the membrane system over the whole length of the muscle fibre.

Animals↗
PubMed1980

[Morphologic analysis of heart development in the chick embryo].

The skeletal muscle is determined under the influence of the earliest pioneer nerve fibers which grow from the neural tube before the 35th incubation hour in the chick embryo. As far as the myocardial determination is concerned, an initial groove influence on the mesodermal cells of the presumptive cardiac area can be postulated. It may also be pointed out that, at the stage of 6-7 somites, neural crest cells come into contact with splanchnopleural cells. Both of these contacts may be regarded as possible myogenic starters of the heat bud and they are not mutually exclusive.

Animals↗
PubMed1980

Non-neural influences in the determination of chick skeletal muscle.

The technique of chicken-quail hybridization in "in vitro" cultures was used. Muscle differentiation of 9 H.H. chick embryo somites without the participation of nerve fibres was noted when they were cultured in the presence of quail pectoral muscle cells. It is suggested that this non-neural model may also be valid "in vivo", and that it probably interacts with the neurodependent mechanism demonstrated in a previous paper.

Animals↗
PubMed1979

[Cholinesterase of the chick optic lobe. Molecular forms and behavior after deafferentation].

The behaviour of AChE and ChE has been studied quantitatively in the chick optic lobe (tectum and nuclei) under normal conditions and after deafferentation. Eye extirpation was carried out at the 1st day after hatching. Both in the tectum and in the nuclei, a low decrease in specific activity was observed, in comparison with the control. Nevertheless, when the total activity is calculated, a significant decrease is evident, owing to marked underdevelopment of the deafferented lobe. In the normal chick lobe, 2 molecular forms of AChE (6.58 and 11S) have been observed. The distribution of these 2 forms is not altered by eye extirpation, until at least 120 days of age.

Acetylcholine↗
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↗
PubMed1976

[Comparative action of chronic injection of alpha toxin from Naja nigricolis and of botulinum toxin A on the development of chick embryo dorsal and ventral spinal roots].

The chronic injection of high doses of alpha toxin from Naja nigricollis or botulinum toxin type A in the yolk sack of developing Chick embryos causes a selective decrease of the number of fibers in the ventral roots of the spinal nerves; at the concentrations needed this reduction is more important with the alpha toxin than with the botulinum toxin.

Animals↗
PubMed1973

Effects of a snake alpha-neurotoxin on the development of innervated skeletal muscles in chick embryo.

The evolution of the cholinergic (nicotinic) receptor in chick muscles is monitored during embryonic development with a tritiated alpha-neurotoxin from Naja nigricollis and compared with the appearance of acetylcholinesterase. The specific activity of these two proteins reaches a maximum around the 12th day of incubation. By contrast, choline acetyltransferase reaches an early maximum of specific activity around the 7th day of development, and later continuously increases until hatching. Injection of alpha-toxin in the yolk sac at early stages of development causes an atrophy of skeletal and extrinsic ocular-muscles and of their innervation. In 16-day embryos treated by the alpha-toxin, the endplates revealed by the Koelle reaction are almost completely absent. The total content and specific activities of acetylcholinesterase and choline acetyltransferase in atrophic muscles are markedly reduced.

Acetylcholinesterase↗