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Biomedical subjects

C Jacque

Publications and source records attributed to C Jacque.

At least 55 records · Page 3Linked to original sources
PubMed1984

Cell-free synthesis of myelin basic proteins in normal and dysmyelinating mutant mice.

Total polyribosomes were isolated from the brains of 16-20 day C57BL/6 mice, four neurological mutants (qk/qk, shi/shi, mld/mld, and jp/Y), and four heterozygote or littermate controls (qk/+, shil/+, mld, and jp littermates) and translated in a homologous, cell-free system. No differences were observed among the nine genotypes in either the yield of polysomes (32.2 +/- 0.6 A260/g brain) or in the incorporation of [35S]methionine into trichloroacetic acid-precipitable protein. However, when the four myelin basic proteins (BPs) were isolated from the translation mixtures little incorporation of [35S]methionine into the BPs was noted in those assays directed by polysomes from mld/mld or from shi/shi animals. Compared with C57BL/6 polysomes, mld littermate and shi/+ polysomes incorporated approximately half the levels of label into the four BPs while qk/+ and qk/qk incorporated normal and close-to-normal levels. Polysomes from jp littermates and jp/Y brains synthesized 66% and less than 15% of the levels of the 14K BP compared with C57BL/6 polysomes. Incorporation of label into the other three BPs was normal with jp littermate polysomes and about half the control levels with jp/Y polysomes. The data indicate that shi/shi and mld/mld mutants either produce altered BPs not recognized by our antibody or synthesize very low levels of BP. The data provide additional support for the notion that the qk/qk mutant synthesizes much higher levels of MBP than are incorporated into myelin. They also indicate that in the jimpy mutant the synthesis of the four BPs is affected to differing extents; thus, the mutant cannot be easily characterized as either an "assembly" or "synthesis" defect.

Animals↗
PubMed1984

[Recent data on Schwann cells].

Because of the role they play in the physiopathology of peripheral neuropathies, Schwann cells have been the subject of numerous studies for some ten years. Schwann cells originate in the ectoderm. They migrate along the myelinated and the unmyelinated axons of peripheral nerves, and lie on a basal lamina. They are responsible for the myelination of peripheral nerves; whether the Schwann cell does or does not form a myelin sheath is determined by the type of axon with which it associates. Recent techniques, such as chimaeric quail-chick embryos, biochemical analysis of human peripheral nerve biopsies, Schwann-cell cultures, nerve grafts, mouse mutants, have permitted some progress. The biochemical composition of peripheral myelin is almost completely known. In vitro, Schwann cells can synthesize myelin-specific molecules. Interactions between axons, Schwann-cells and extra-cellular space have been observed.

Animals↗
PubMed1983

Survival and differentiation of oligodendrocytes from neural tissue transplanted into new-born mouse brain.

Fragments of new-born mouse central nervous system have been transplanted into new-born mice host brains, under conditions in which the myelin synthesized by the oligodendrocytes included in the graft, could be distinguished from the host myelin. The work demonstrates that transplanted oligodendrocytes survive in the host brain, migrate out of the graft and synthesize myelin. No sign of rejection was observed during the time of the experiment.

Animals↗
PubMed1983

Myelin basic protein deposition in the optic and sciatic nerves of dysmyelinating mutants quaking, jimpy, Trembler, mld, and shiverer during development.

An ontogenetic survey of the basic protein of myelin, common to both central and peripheral nervous systems, was carried out on normal C57Bl and five dysmyelinating mutant mice. Myelin basic protein (MBP) was quantified by radioimmunoassay in the optic and sciatic nerves of mice from birth to adult stages, giving special attention to the premyelinating and early myelination periods. In the optic nerves of normal mice, MBP was already detectable at birth but the active period of myelin deposition was shown to occur after day 10 postnatal. The timing and rate of accumulation of MBP were normal in Trembler. In contrast, they were abnormal in the other mutants. In the quaking mouse, the active period of MBP deposition was delayed, and its final concentration represented no more than 12% of normal in the adult. No active period of MBP deposition was observed in the other mutants. In the jimpy mouse, a slow accumulation of MBP resulted in a final concentration reaching 2% of the normal value at 25 days. In mild and shiverer mice, the MBP was hardly detectable. In the sciatic nerves of normal mice, the active period of MBP deposition occurred between days 3 and 12 postnatal. No substantial changes occurred in the period of 2 months--2 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Myelin in normal and diseased states.

A general outline of the morphologic structure and biochemistry of myelin, its mode of development and assembly, and its alterations in diseased states, including diagnoses and prognoses of diseases affecting myelin, is given.

Demyelinating Diseases↗
PubMed1982

Myelin basic protein in CSF and blood. Relationship between its presence and the occurrence of a destructive process in the brains of encephalitic patients.

Serum and CSF levels of myelin basic protein (MBP) were measured in 50 patients with encephalitis of various origins and severity. In nearly 50%, the CSF samples were found to display immunoreactivity of MBP. Positivity was found to be correlated with the severity of the clinical signs. More precisely, it corresponded to cases with suspected extensive brain destruction. No relationship could be observed with the cause of disease. Positive tests of sera were infrequent, even from patients whose CSF was rich in MBP. Longitudinal studies performed on 20 patients who were serially investigated during periods ranging from three weeks to 18 months demonstrated that after an attack, MBP liberation into the CSF persists for one to three weeks. The MBP assay should serve as an index for destruction of nervous tissue.

Encephalitis↗
PubMed1981

Similarities and dissimilarities between two myelin deficient mutant mice, Shiverer and mld.

In the brain of Shiverer and mld mutant mice, myelin is poorly compacted and the major dense line of the myelin is practically missing. Major biochemical differences were detected between mutations. In mld myelin, myelin basic proteins are mainly affected and 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNP) exhibits a very high specific activity. In Shiverer myelin, in addition to basic proteins, all major myelin proteins are also decreased while CNP specific activity is moderately increased.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1981

Regional distribution of myelin basic protein in the central nervous system of quaking, jimpy, and normal mice during development and aging.

Myelin basic protein (MBP) was quantified using a RIA technique in the spinal cord, cerebellum, diencephalon plus brainstem region and cerebral hemispheres of two dysmyelinating murine mutants, quaking (qk) and jimpy (jp) mice. Comparison was made with normal control values. The whole life-span has been investigated: ie, ages ranging from 0 to 26 days for the jp, O to one year for the qk, and prenatal stage to three years for the control animals. Assays in the mutants at early ages were rendered feasible by the use of marker genes, which has allowed the diagnosis of the mutation at birth, 12 days before the expression of their typical tremor phenotype. Special care was given to the period of early myelinogenesis in order to clarify the dysynchrony between the various parts of the central nervous system. In normal mice, MBP was already detected in the brain of 19-day-old embryos. During development, rapid accumulation of MBP first occurred in the spinal cord then in the diencephalon, the brainstem, the cerebellum, and finally in the cerebral hemispheres. In the 25-day-old jimpy mutant, levels of MBP were found dramatically decreased, never exceeding 6% of the normal controls in any of the areas investigated. The situation for the quaking mouse was quite different. This mutant could be investigated up to one year old. At that age, a high discrepancy was observed between the values found in the brain and in the spinal cord (respectively, 10% and 35%) compared to normal controls. In both mutants, not only were the levels of MBP decreased, but also its appearance during development was delayed. Nevertheless, in both mutants the caudo-rostral timing of myelination as assayed by MBP levels was maintained. Furthermore, the later myelination occurred, the stronger weas the deficit in MBP. Interestingly, in the quaking mutant, the specific plasticity of the spinal cord was exemplified by its ability to reduce constantly, even at an advanced age, its initial deficit of MBP.

Aging↗
PubMed1981

Glial fibrillary acidic protein. A cellular marker of tanycytes in the mouse hypothalamus.

The differentiation of tanycytes during development of the mouse hypothalamus has been followed by immunohistochemistry with a GFA protein antiserum. Radially oriented processes of the tanycytes were stained with GFA antiserum in the ventral and the dorsal lining of the third ventricle in the mouse neonate and at later ages. Typical astrocytes in the hypothalamus could not be visualized before 16-20 days postnatally. These results indicate that tanycytes, which acquire their final position early in embryonic development, exhibit a structural feature of fully differentiated astrocytes early in postnatal development.

Animals↗
PubMed1981

[Leukoencephalopathy in childhood leukemia (author's transl)].

Severe leukoencephalopathy occurred in three of thirty children after preventive central nervous system therapy (24 gray cranial and intrathecal methotrexate) for acute lymphocytic leukemia. Two of these children, in complete remission although chemotherapy was discontinued, have major neurological defects. This preventive therapy remains mandatory but some modifications could be discussed. The mechanism and the possibilities of prevention or of early recognition of this severe neurological impairment are discussed with references to other published cases.

Adolescent↗
PubMed1981

[Neurochemical data concerning glial tumors. Contribution of the estimation of the G.F.A. protein to the diagnosis and prognosis of gliomas (author's transl)].

The Glial Fibrillary Acidic (G.F.A.) protein is a specific component of the gliofilaments present in the astrocytes. Its immunochemical determination on tumor fragments obtained at surgery has permitted to draw clinico-biochemical correlations between the G.F.A. content of a glioma and its histological grade. The more a glioma is dedifferentiated, the lower is its content of G.F.A. This determination is a biochemical index of dedifferentiation. However, its pronostic value is not established yet.

Astrocytes↗
PubMed1980

[Value of the estimation of gliofibrillary acid protein in the diagnosis of glial tumours (author's transl)].

Glial Fibrillary Acidic Protein (G.F.A.P.) is characteristic of astrocytes. Its estimation in a tumour fragment removed surgically may be used to confirm whether or not a cerebral tumour is glial in nature. This was confirmed here by study of 6 cases. G.F.A.P. levels were normal only in the 2 patients whose cerebral tumours were not glial. It remains to be determined whether this estimation may be used to define a particular treatment or prognosis.

Adolescent↗
PubMed1980

Accumulation of GFA, the monomeric precursor of the gliofilaments, during development in normal mice and dysmyelinating mutants.

Astrocytic reactivity during the myelination period in the mouse was studied with immunochemical method, ie, quantitative determination of the soluble pool of the GFA protein. There is normally a maximum content at the time of early myelinogenesis in any structure; then the GFA level decreases and finally keeps constant for a long period during the adult life. This evolutive pattern is also observed in the dysmyelinating mutant quaking, with a permanent shift toward higher values especially in areas of earlier maturation. In the jimpy mutant, practically devoid of myelin, the increase of GFA occurs but does not stop until death, at 25 days postnatal. This study points out 1) the capacity of astrocytes to synthesize surprisingly high amounts of soluble GFA at periods of intense metabolic activity, and 2) the reactivity of astrocytes in relation to the degree of deficiency of the myelinating oligodendrocytes.

Animals↗
PubMed1980

Immunohistochemical localization of the myelin basic protein and of the glial fibrillary acidic protein: comparative study in normal, quaking and jimpy mice.

The topographical distribution of myelin basic protein (MBP) and of glial fibrillary acidic protein (GFA) have been compared in the CNS of 18-day-old normal, quaking, and jimpy mice using indirect immunofluorescence. Comparison was made in brain and spinal cord sections. MBP was strongly decreased in quaking and jimpy mice in all parts of the CNS. A pronounced gliosis was observed in jimpy mice with occurrence of numerous hypertrophied astrocytes. To a lesser extent, an astrocytic reaction was also observed in quaking CNS.

Animals↗
PubMed1980

Radioimmunoassay of the myelin basic protein in biological fluids, conditions improving sensitivity and specificity.

The radioimmunoassay (RIA) for myelin basic protein (MBP) in biological fluids was reassessed in order to improve its sensitivity and eliminate some interferences. By using the preincubation technique and the charcoal-dextran-horse serum mixture for the separation step, the detection limit could be lowered to 200 pg/ml for cerebrospinal fluids (CSF), amniotic fluids (AF) and nervous tissue extracts and 600 pg/ml for sera. The RIA could be used directly on CSF, AF and nervous tissue extracts. Sera, however, had to be heated in citrate buffer at 100 degrees C in order to discard interfering material. The present method is 10 to 20 times more sensitive than others previously published. Moreover, it can be applied to amniotic fluid. The biological fluids had to be promptly frozen to avoid degradation of MBP.

Amniotic Fluid↗