Biomedical subjects

G Nicolardi

Publications and source records attributed to G Nicolardi.

16 recordsLinked to original sources

PubMed1992

GFAP-immunoreactive perivascular glia in the chick optic tectum.

Immunocytochemical staining of the glial fibrillary acidic protein (GFAP) was utilized to characterize the processes of the astrocytes enveloping the vessel wall in the central nervous system. The study was carried out in the mesencephalic lobes of 18 and 20 incubation-day chick embryos and of 20 day chickens. A perivascular GFAP positivity was mainly detectable in the vessel portions running within the tectum white layers, while it was scarce, or absent, in the grey ones. The perivascular GFAP negativity in the tectum cellular layers was not considered result of the absence of astrocytic endfeet since our previous electronmicroscopical studies evidenced an almost complete perivascular astrocytic ring throughout the tectum layers at hatching time. Present data rather suggest that the expression of the GFAP-made intermediate filaments in developing astrocytes might be controlled by the surrounding microenvironment.

Animals↗

PubMed1992

Further data on the development of SRIF-like immunoreactive nerve cell populations in the chick embryo brain stem. I. Medulla and pons.

Further immunocytochemical analysis of the neuroblasts with SRIF-like immunoreactivity (ir) was carried out on the chick embryo medulla and pons. 5 or 100 microns rombencephalon sections were obtained from 60 White Leghorn chick embryos at stages (E = Embryonic days) ranging from E4 1/2 to E18 and incubated with rabbit polyclonal antibodies against synthetic cyclic Somatostatin-14, according to PAP-DAB technique. In the medulla and pons the ir appeared as from E12. From E12 to E13 1/2-E14 the ir distribution gradually changed. From E14 to E18 numbers and spatial arrangement of the positive neuroblast groups did not show substantial changes; in these respects the ir distributional pattern proved to be markedly different from the one observed by the Authors in adult animals. Moreover, from E13 to E15 the positive neuroblast density appeared to be higher than that of positive neurons in adults. These results are consistent with a possible SRIF local regulative role.

Animals↗

PubMed1992

Further data on the development of SRIF-like immunoreactive nerve cell populations in the chick embryo brain stem. II. Midbrain tegmentum.

Further immunocytochemical analysis of the neuroblasts with SRIF-like immunoreactivity (ir) was carried out on the chick embryo midbrain tegmentum. 5 or 100 microns mesencephalon sections were obtained from 60 White Leghorn chick embryos at stages (E = Embryonic days) ranging from E4 1/2 to E18 and incubated with rabbit polyclonal antibodies against synthetic cyclic Somatostatin-14, according to PAP-DAB technique. In the midbrain tegmentum the ir appeared as from E12. From E12 to E13 1/2-E14 the ir distribution gradually changed. From E14 to E18 numbers and spatial arrangement of the positive neuroblast groups did not show substantial changes; in these respects the ir distributional pattern proved to be similar to the one observed by the Authors in adult animals. From E17 to E18 a decrease in the positive neuroblast density appeared to occur, particularly in a ventrally placed group. These results are consistent with a possible local regulative role of the SRIF.

Animals↗

PubMed1991

Double-labelling data on somatostatin-like and tyrosine-hydroxylase-like immunoreactivities in chick embryo brain stem. I. Pons and mesencephalon.

With the aim of investigating some factors and mechanisms of the chicken brain development, the same thick sections of brain stems from twelve E13-to-E21-aged chick embryos were sequentially tested with a rabbit anti-Somatostatin antiserum, using a PAP-DAB technique, and with anti-tyrosine hydroxylase (-TH) monoclonal antibodies, using an indirect immuno-fluorescence technique. As regards the pons and mesencephalon, the following main results were obtained. At E21 almost the same distribution of the TH-like immunoreactivity (ir) as at E13 was observed. Neuroblasts in a central, relatively wide region of mesencephalic tegmentum and in the central portion of the pons showed TH-like ir. A co-localization of the 2 immunoreactivities was detected only at E18, within some neuroblasts of the mesencephalic and pontine regions with TH-like ir. It is possible that this transitory co-localization plays a role in the development of the pons and mesencephalon of this species.

Animals↗

PubMed1990

Intestinal ischemia: morphological features--II.

Superoxide radicals produced during acute intestinal ischemia are biochemically related with the presence of hydrogen peroxyde. In this study we have investigated the distribution of peroxidase-catalase activity, histochemically determined, in the ischemic ileal wall. In the rat, complete arterial and venous occlusion produced a progressive increase in extra-vascular peroxidase-catalase activity with a maximum corresponding to the ileal wall. Probably the tissue peroxidase-catalase activity is related to massive degranulation of polymorphonucleates.

Animals↗

PubMed1990

Intestinal occlusion: morphological features.

In this research we studied the possible relationships between the level and the distribution of peroxidase-catalase activity and the degree of the morphological changes in the intestinal wall during mechanical occlusion. These researches have really proved that the increase of the peroxidase-catalase enzymes correlate proportionally with the damage of intestinal wall.

Animals↗

PubMed1990

Intestinal ischemia: morphological features--I.

In this research we studied the interrelationships between the progression of morphological damage and leucocyte populations in the last ileal loop after blockage of blood supply subsequent to arterial and venous occlusion. Our morphological data on the staging of the ileal wall damage agree with those reported in literature. In addition we described that in the ischemic loop the number of lymphocytes appear decreased and polymorphonuclear cells degranulate actively.

Animals↗

PubMed1988

Medullary and mesencephalic neuronal groups reacting to antibodies against VIP, somatostatin and bombesin in adult Gallus gallus domesticus.

The caudo-cranially intermediate one-third of medullary dorsal region, the periaqueductal grey and the rostro-ventral portion of the midbrain tegmentum of adult chickens were studied in detail by means of the PAP-DAB procedure, to define further the main morphological features of the neuronal populations that in previous studies had shown VIP (Vasoactive Intestinal Polypeptide),-Somatostatin (SRIF)-, and Bombesin-like immunoreactivities. In the medulla, VIP-like immunoreactivity was detected within neuronal bodies and processes and extended down to the cervical spinal cord. SRIF-like immunoreactivity was seen only within nerve cell processes, at least a part of which could be sensitive fibre terminals. Bombesin-like immunoreactivity was observed only within neuronal processes. In the periaqueductal grey, all 3 immunoreactivities were detected within perikarya and neuronal processes, with a higher density cranially. In the rostro-ventral portion of the midbrain tegmentum, VIP-like and Bombesin-like immunoreactivities were detected (the latter being located somewhat more cranially) both in neuronal bodies and in processes. SRIF-like immunoreactivity was found in this region only in long neuronal processes.

Animals↗

PubMed1987