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Biomedical subjects

C Francois

Publications and source records attributed to C Francois.

32 records · Page 2Linked to original sources
PubMed1985

A histological atlas of the macaque (Macaca mulatta) substantia nigra in ventricular coordinates.

An atlas of the macaque substantia nigra was established in ventricular coordinates. Having verified that nigral contours are stable in both Macaca mulatta and Macaca speciosa, the antero-posterior sequence of four subdivisions was described on eight vertico-transverse levels after a comparison between histological and histochemical data. The pars reticulata constitutes the anterior pole containing pale, small cell-bodies scattered among the numerous endings of the striato-pallido-nigral fibres. Anteriorly, the pars compacta forms the dorsal border of the substantia nigra, but more posteriorly, it leaves the dorsal border and develops ventral fringes. Its large cell-bodies, most often pigmented, rich in Nissl bodies and in acetylcholinesterase, are closely spaced among a few axonal fascicles. The pars lateralis contains a low density of cell-bodies and corresponds to the hilum of entrance of the striato-pallido-nigral fibres and gives rise to a nigro-tectal projection. The pars mixta, dorsally located, contains a low density of neurons varying considerably in size. It represents the hilum of exit of nigral axons which project to various targets.

Anatomy, Artistic↗
PubMed1984

Accessibility and cross-linking of native neurofilaments to chemical reagents.

Native neurofilaments were submitted to cross-linking reactions with bifunctional reagents (DMA, DMS and DSS) and to chemical reactions with sterically bulky reagents such as EEDQ and DTAF , as well as a glutaraldehyde-activated gel. The 160K and 70K neurofilament proteins reacted slightly more than the 210K neurofilament protein with DMS and DSS. The accessibility of the three neurofilaments to the other chemical reagents was identical. These results were unexpected since neurofilament antibodies seem to react preferentially with 210K protein which is at the periphery of the filament, whereas the 70K protein, which is the backbone of the filament, is probably buried inside the filament. In the same way, it has been shown that the side of the 210K proteins are probably able to cross link the neurofilaments with non covalent and covalent bridges. Using different cross link reagents, we did not observe a characteristic reactivity of the 210K protein towards the different chemicals. We conclude that the three neurofilament proteins are equally exposed to the different sterically bulky reagent and that part of the polypeptide chain of the 70K and the 160K proteins are located at the outside of the filament.

Animals↗
PubMed1984

Localization of nigrostriatal, nigrothalamic and nigrotectal neurons in ventricular coordinates in macaques.

The topography of the substantia nigra and its subdivisions was first analysed in macaques by using a topographic technique based on ventricular landmarks. This study shows the stability of the contours of the substantia nigra and its subdivisions in various species of macaques. The anteroposterior sequence of four subdivisions was standardized by defining eight verticotransverse levels, regularly interspaced and systemically used for each experimental case. Neurons of the substantia nigra sending axons to the striatum, thalamus and superior colliculus were identified by the technique of retrograde transport of horseradish peroxidase. The nigrostriatal labeled neurons were essentially located in the ipsilateral pars compacta but also scattered dorsally in the pars mixta and ventrally in the pars reticulata. In addition, the existence of a crossed nigrostriatal pathway was demonstrated in monkeys. Nigrothalamic labeled neurons were found in the whole pars reticulata at rostral levels and only in the medial part at more caudal levels. Comparatively, nigrotectal labeled neurons were also found in the whole pars reticulata at rostral levels, but caudally, they were confined to the lateral part of the pars reticulata and the pars lateralis. It thus appears that these three nigral components may overlap at some levels of the substantia nigra. This is discussed in relation to the existence of branched axons already documented. However, the present results underline the strong tendency of the nigrotectal neurons to be segregated from the nigrothalamic ones and to be laterally located in monkeys. In addition, two nigrotectal components have been identified on the basis of their topography and their somata size: one with large somata located in the pars lateralis, probably specific to primates, and the other with smaller somata located in the pars reticulata. These two components may indicate the existence of two different functional systems.

Animals↗
PubMed1983

Peroral infection of suckling mice with milk-borne mouse mammary tumour virus: uptake of the main viral antigens by the gut.

Persistence of mouse mammary tumour virus (MMTV) components in the digestive tract of suckling mice was investigated by immunoperoxidase staining of the main viral antigens and micro-immunoenzyme assays of gp52 and p28; these latter assays were also performed after ingestion of milk enriched in viral antigens using Cr2O3 as a marker for the alimentary bolus migration. When compared to the ingested antigens, the amounts of gp52 and p28 decreased during transit, p28 being more rapidly digested than gp52. The antigens were, however, destroyed to a much larger extent in the gut of the adult than in that of the newborn mouse. A fraction of the marker remained for a long time in the stomach; a prolonged retention was also observed with gp52 and especially with p28. Significant amounts of viral antigens were detected in the intestinal walls: both p28 and gp52 were found in the duodenum and small intestine. Moreover, the four viral antigens gp52, gp36, p28 and p8 were clearly observed in very large supranuclear vacuoles inside the epithelial cells of the distal part of the gut. Total particles can reach the intestine; the viral material could then be either destroyed or taken up in the epithelial cells by endocytosis, so that the intestinal epithelium might serve as a portal of entry for MMTV in the suckling mouse.

Animals↗
PubMed1981

Topographical and cytological localization of iron in rat and monkey brains.

The topographical localization of endogenous iron in rat and monkey brains coincides with the striato-pallido-nigral and the cerebellar corticonuclear pathways. EM observation reveals that iron is located in the soma and processes of glial cells and, above all, in the inner and outer loop of the myelin sheets. This raises the question of whether iron intervenes in some GABAergic systems.

Animals↗
PubMed1981

Immunological characterization of a mammary tumour virus from Swiss mice: multiple epitopes associated with the viral gene products.

The major antigens of a mouse mammary tumour virus (MMTV) isolated from the milk of exogenously infected MB+ Swiss mice were compared with the viral components of other MMTV strains by using the methodology developed by Teramoto et al. (1977 a). The anti-gp47 (Swiss) serum differentiated between type- and group-specific antigenic determinants on the major glycoprotein; two distinct type-reactivities were demonstrated, one of them being shared by the MMTVs (Swiss) and (RIII), and the other by the MMTVs (C3H) and (GR). The MMTVs (Swiss) and (RIII) also reacted identically in a 'type-specific' assay using an anti-p28 (Swiss) serum, but a distinct reactivity was observed with the MMTV (C3H). In the isologous test where an anti-(total RIII) serum was used to bind intact, externally labelled RIII virions, the Swiss virus was seen to possess a type-specific determinant on its surface which distinguished itself from both MMTVs (RIII) and (C3H). The Swiss/fC57BL mice (which are devoid of the milk virus and for this reason are referred to as MB-), expressed only the internal virus antigens in their mammary glands. Under the 'type-specific' assay conditions, the p28 antigen present in the mammary gland extracts of the MB+ mice was indistinguishable from the p28 antigen purified from the Swiss virion, but was clearly distinct from the p28 reactivity present in the mammary gland extracts of the MB- mice. The p28 (MB-) antigen may thus represent the expression of an endogenous virus sequence different from the milk virus genome.

Animals↗
PubMed1976

Comparative study of the milk fat globule membrane and the mouse mammary tumour virus prepared from the milk of an infected strain of Swiss albino mice.

Milk fat globule membranes and mammary tumour virus particles (d=1.17 g/cm3) have been obtained from the milk of a Swiss albino mice strain. Comparative biochemistry shows that these two structures differ significantly in the phospholipid, polypeptide and glycopolypeptide patterns and enzymatic activities. However, the lipid profile and the morphology of both structures suggest a filiation with the plasma membrane. Density fractions obtained from the crude virus preparation have been thoroughly investigated. The results suggest that most of these fractions represent degraded virus and/or atypical virus assembly.

Animals↗
PubMedDate not supplied

[Hyperparathyroidism due to parathyroid carcinoma located in the mediastinum].

Parathyroid gland carcinoma is a rare cause of primary hyperparathyroidism. The authors discuss the case of a 56-year-old man who presented with hypercalcemia and multiple bone lesions suggestive of tumor metastases. Laboratory and radiological investigations revealed primary hyperparathyroidism in a patient with evidence of osteitis fibrosa cystica, sustained by carcinoma of a mediastinal parathyroid gland. Early titration of parathyroid hormone (PTH) levels in all patients with hypercalcemia of unclear cause is important for early diagnosis of cases that are tumor-sustained and prevention of the most severe complications. The role of immunostaining with anti-PTH antibodies in demonstrating parathyroid gland tissue in ectopic and/or non-functioning primary tumors, as well as metastases, is also discussed.

Bone Neoplasms↗