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Biomedical subjects

L Leger

Publications and source records attributed to L Leger.

At least 37 records · Page 2Linked to original sources
PubMed1985

Evidence for synenkephalin-like immunoreactivity in pontobulbar monoaminergic neurons of the cat.

Using indirect immunofluorescence, evidence that enkephalin- and synenkephalin-like-immunoreactivities are colocalized within numerous monoaminergic neurons of the cat pontobulbar formation is presented. The colocalization concerns most catecholaminergic cell bodies in the locus coeruleus region and numerous serotoninergic cell bodies in the raphe nuclei. Synenkephalin is the 1-70 N-terminal region of the bovine adrenal medulla proenkephalin. Therefore, the proenkephalin (or a related) system seems to represent the biosynthetic pathway for the enkephalins immunodetected within these monoaminergic neurons.

Animals↗
PubMed1984

Identification of catecholamine cell bodies in the pons and pons-mesencephalon junction of the cat brain, using tyrosine hydroxylase and dopamine-beta-hydroxylase immunohistochemistry.

Using a double labeling immunohistochemical method with antibodies to tyrosine hydroxylase and dopamine-beta-hydroxylase, we reexamined the topographical distribution of dopaminergic (DA) and noradrenergic (NA) cells in the pons-mesencephalon junction of the cat. Besides DA cells of SN and its extensions, DA cells were also observed more caudally in nucleus raphe linearis intermedius and dorsalis, decussation of brachium conjunctivum, fasciculus longitudinalis medialis and periaqueductal gray. In nucleus locus coeruleus, cells exhibited variable levels of DBH, but dopaminergic cells were not evidenced in this structure.

Animals↗
PubMed1984

[The co-localization of monoamines and enkephalins in the central nervous system].

After examination of some particular methodological problems concerning the visualization of monoaminergic and "enkephalin containing" central neurones, the colocalisation of enkephalins in certains monoaminergic neurones is reported. Thus, in rat and cate raphe nuclei many serotoninergic cell bodies display enkephalin-like immunoreactivity (ELI). In the cat locus coeruleus complex most catecholaminergic neurones contain ELI. Further, the synthesis in situ of enkephalins is strongly suggested by the fact that synenkephalin-like immunoreactivity is also detected in these monoaminergic neurones. Synenkephalin is the N terminal part to the bovine medullosurrenal pro-enkephalin. Monoamine-enkephalin colocalisation has been shown in peripheral neurones and adrenal medulla. The possible functionnal significance of the coexistence of monoamine-enkephalins in neurones is discussed. In particular, some hypothetical levels of interaction are considered.

5,6-Dihydroxytryptamine↗
PubMed1982

[Attempts at transplanting the pancreas (author's transl)].

Two techniques are competing for pancreatic transplantation. One is auto-transplantation of the islets after mechanical slicing and treatment with collagenase, the resulting produce being injected into the portal vein, and the other consists of transplanting a pancreatic segment obtained from cadavers or live donors by obliteration of the ducts with glue. The latter seems to be preferred.

Animals↗
PubMed1982

Fringe pattern photobleaching, a new method for the measurement of transport coefficients of biological macromolecules.

The conventional method of studying mass transport in membranes by spot photobleaching and then following the recovery of fluorescence has disadvantages. Among them, the need for a high density of fluorescent molecules, the measurement of the beam profile, and a knowledge of the photobleaching processes are of a crucial importance. The application of a planar fringe pattern of light both for the bleaching and the monitoring of the fluorescent molecules solves these three major difficulties. Brownian diffusion coefficients and flow velocities can be measured independently and are averaged over the whole fringe pattern volume. These transport coefficients are explored over the wide range of experimentally accessible distances (from an interfringe spacing 0.5-50 micron). The quantification of the mobile and immobile components is further simplified by scanning the fringe pattern and detecting only a modulated fluorescence recovery signal. The fringe pattern photobleaching method is particularly adapted to the measurements of diffusion coefficients and flow velocity of membrane components, as well as of cytoplasmic proteins. The theoretical results and the test experiments with fluorescent bovine serum albumin are described.

Animals↗
PubMed1981

[Blood gastrin levels after electrical stimulation of the vagus (author's transl)].

Acid secretion from the cells bordering the gastric fundus may be stimulated by a direct action of histamine or pentagastrin... or from electrical stimulation of the vagus as used to control vagotomy. It is not known, however, whether this latter effect is due to direct stimulation of the lining cells or follows hypersecretion of gastrin. In order to clarify this point, a stimulus was applied to the isolated vagus during vagotomy, and gastric acid and peripheral blood gastrin levels measured. Increased or decreased gastrin levels were noted in about the same number of cases. No direct relationship with pH variations was observed, and confirmation that vagal stimulation affects the lining cells through the intermediary of increased systemic blood gastrin levels was not obtained.

Animals↗
PubMed1980

[A study of the specificity of amylases. Measurement of pancreatic isoamylases (author's transl)].

Serum lipase, pancreatic isoamylases and serum inhibitory activity on proteases were measured in 29 patients, 17 of whom had pancreatic disorders. The new test used to measure pancreatic isoamylases is rapid and useful, as it is relatively specific of pancreatic lesions. In acute abdominal syndromes, it undoubtedly enhances the value of biochemical investigations by confirming or excluding pancreatic lesions or involvement.

Amylases↗