Biomedical subjects

J M Warter

Publications and source records attributed to J M Warter.

At least 19 recordsLinked to original sources

PubMed1992

Specific effect of corticoids on acetylcholine receptor expression in rat skeletal muscle cell cultures.

The potential effect of different classes of steroids on the expression of acetylcholine receptors (AChR) was studied in different primary cultures of newborn-rat skeletal muscle cells. Comparison among three techniques for preparing newborn skeletal muscle cells showed that these systems were equivalent to study AChR expression. Only corticoids stimulated myogenesis as a twofold increase in AChR expression indicated. Among the corticoids, the glucocorticoids were the more potent, whereas the mineralocorticoid aldosterone had less marked effect. The sex hormones progesterone and testosterone partially blocked these effects, without inducing any significant effect when given alone. The steroids tested differed in efficacy in correlation with their different chemical structures. Among the glucocorticoids a clear structure-activity relationship could be established. These results emphasize the specificity of corticoid action on muscle cells and suggest an explanation for the effects induced by glucocorticoids used in treating human muscular or neuromuscular diseases.

Adrenal Cortex Hormones↗

PubMed1992

Intestinal carcinoid tumor and myotonic dystrophy. A new association?

The occurrence of multiple carcinoid tumors of the small bowel with liver metastases is reported in a patient with a previous myotonic dystrophy. In addition to the association of myotonic dystrophy with multiple endocrine adenomatosis type 2A, hyperparathyroidism, and neurofibromatosis, this case report gives further evidence for the propensity of such patients to develop neuroendocrine tumors.

Carcinoid Tumor↗

PubMed1992

Familial motor neuron disease with Lewy body-like inclusions in the substantia nigra, the subthalamic nucleus, and the globus pallidus.

In a familial case of motor neuron disease (MND), 2 unusual features were noted in the necropsy. The first was a pallidoluysonigral degeneration, observed in only 4 other cases of MND and which was here asymptomatic. The second was the presence in degenerated spinal cord anterior horns and in degenerated basal ganglia of neuronal Lewy body-like inclusions stained by antibodies against ubiquitin.

Genes, Dominant↗

PubMed1992

Chronic administration of NMDA antagonists induces D2 receptor synthesis in rat striatum.

Dopamine D2 receptor gene expression was examined in rat striatum after chronic treatment with N-methyl-D-aspartate (NMDA) receptor antagonists (ketamine at 15 mg/kg/day or MK-801 at 0.1, 0.2 and 0.4 mg/kg/day per os, for 50 days). The long-isoform mRNA, as well as the total D2 mRNA expression were induced. No change was noticed in striatal dopamine release or turnover. D2 binding studies carried out in MK-801 chronically treated (0.3 mg/kg/day per os, for 50 days) and control rats revealed an increased receptor density in treated animals without a significant change in receptor affinity. These results suggest that the synthesis of both striatal D2 receptor isoforms is postsynaptically regulated at the transcriptional level, by events triggered by glutamate through the NMDA-type receptor.

Animals↗

PubMed1992

[Prion encephalopathies].

Spongiform encephalopathies, also called prion encephalopathies, are characterized, in human as well as in animals, by (1) their clinical picture which indicates strict localisation in central nervous system, (2) their histological aspect: spongiform degeneration and neuronal loss, and (3) their transmissibility in the same animal species but also from man to animal. The nature of the pathogenic agent is still debated. This agent could be one isoform of the prion protein which, probably because of a modification of its tertiary structure, is partially resistant to proteolytic enzymes. Recent description of a bovine spongiform encephalopathy caused by meat flour absorption has raised again the question of the transmissibility of these animal diseases to human.

Animals↗

PubMed1992

Gerstmann-Sträussler-Scheinker disease in an Alsatian family: clinical and genetic studies.

The clinical progression of Gerstmann-Sträussler-Scheinker disease in a family of Alsatian origin is reported. The age of onset and the duration of evolution were variable. The clinical picture became more complex over the generations: in the first generations, isolated dementia and in later generations a triad of pyramidal, pseudobulbar syndromes and dementia associated with spinal cord and cerebellar features. Prion gene analysis showed that four surviving patients carry double missense changes at codons 117 and 129, identical to those found in one case at necropsy and 10 other healthy members of the family. The missense changes were not found in 100 controls. No member of the family had modification of condons 102, 178, or 200. The lod score suggests linkage between the missense change at codon 117 and Gerstmann-Sträussler-Scheinker disease in this family.

Adult↗

PubMed1992

[Chronic administration of N-methyl-D-aspartate (NMDA) receptor antagonists induced in rats, a facilitation of striatal dopaminergic type D2 transmission: behavioral and biochemical study].

Compared with control rats, rats treated with ketamine (15 mg/kg/day, p.o.) or MK-801 (0.1 to 0.4 mg/kg/day, p.o.) for 6 weeks showed significantly increased: 1) behavioural responses to D2 dopaminergic agents, either agonist or antagonist, 2) striatal D2 receptor mRNA expression, 3) striatal D2 receptor density, without any presynaptic change in dopaminergic or serotoninergic neurotransmission. These results suggest that the functional expression of striatal D2 receptor is postsynaptically regulated by glutamate-triggered events through the NMDA receptor subtype.

Animals↗

PubMed1992

[Ubiquitin and degenerative diseases of the central nervous system].

Ubiquitin is an ubiquitous 76 aminoacids protein that is present in all cellular compartments. It intervenes in numerous functions of cell metabolism, and in particular in non-lysosomal (but also lysosomal) lysis of altered or short-lived proteins. Immunohistochemical studies have shown that it is present in many inclusions characteristic of neurodegenerative diseases, notably in Lewy bodies, neurofibrillary tangles of Alzheimer's disease, Pick bodies and also in inclusions characteristic of certain motor neuron diseases. The presence of ubiquitin in these inclusions raises 2 questions: (1) the nature of the target proteins, probably altered proteins of the cytoskeleton; (2) the significance of ubiquination: it might reflect the degeneration process or participate in the protection of cells against degeneration or be an active factor in programmed cell death.

Brain Chemistry↗

PubMed1992

Malignant thymic lymphoblastic lymphoma and myasthenia gravis: an exceptional association.

Thymic lymphoblastic lymphoma and myasthenia gravis rarely coexist. Only two cases have been reported and we describe here a third case. A 60 year old man presented a typical history of myasthenia gravis, confirmed by neurological investigations including electromyography. Chest X-ray revealed an anterior mediastinal tumor. At thoracotomy, a 60 mm mass adherent to the pericardium was excised and a lymphoblastic lymphoma was diagnosed. The lymphogram showed enlarged pelvic and abdominal lymph nodes consistent with lymphoma. A m-BACOD chemotherapy regimen gave rapid and complete remission of both lymphoma and myasthenia gravis and the patient is now alive 25 months after the start of chemotherapy with no evidence of disease.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1991

Behavioural, pharmacological and biochemical effects of acute and chronic administration of ketamine in the rat.

The effects of N-methyl-D-aspartate (NMDA) antagonist ketamine given acutely or chronically were investigated on dopamine-related motor functions. Acute administration (15, 22.5, 30 mg/kg, i.p.) reversed the catalepsy induced by a dopamine (DA) antagonist (haloperidol, 0.25 mg/kg, i.p.) in the rat. When given orally and chronically (15 mg/kg per day) during at least 60 days, no alteration of spontaneous motor behaviour was observed, but the responsiveness to a DA agonist (apomorphine, 0.125 or 0.25 mg/kg s.c.) and to haloperidol was enhanced, suggesting an hypersensitivity of the DA receptors following the chronic blockade of NMDA receptors. However, following prolonged administration of ketamine there were no alteration of DA levels and turnover. Taken together these results suggest that the mechanisms involved in this DA receptor hypersensitivity should be postsynaptic.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1991

Thoracic intradural arachnoid cyst: possible pitfalls with myelo-CT and MR.

A thoracic intradural arachnoid cyst presenting as an intradural extramedullary mass highly suggestive of psammoma on myelogram and myelo-CT is reported in a 34-year-old female. High densities of the cyst were related to collection of contrast media within the cyst. However MR examination of the thoracic spinal cord including sagittal T1 (without and with contrast) and T2 studies failed to demonstrate the mass. Lack of MR changes were related on one hand to the small size of the cyst and to the absence of mass effect on the spinal cord, and on the other hand to a CSF-like signal of the contents of the cyst. Only combination of myelography, myelo-CT and MR allows precise diagnosis of small intradural arachnoid cyst; however MR is the method of choice for evaluation of large intradural subarachnoid cysts.

Adult↗

PubMed1991

Nuclear magnetic resonance T2 relaxation times in multiple sclerosis.

An original method was used to carry out the mathematical analysis of T2 transverse magnetization decay curves and the measure of T2 relaxation times on multiple sclerosis (MS) patients. The presumably normal white matter (WM) of these patients presented higher T2 relaxation times (98.6 msec), in comparison with that found in a population sample (88 msec). In this case, magnetization decay curves remain mostly monoexponential and are characterized by a single T2. On the other hand, areas of increased signal (AIS) curves are always better fitted by a biexponential function characterized by a short (82 msec) and a long (greater than 200 msec) T2. The spreading out of long T2 varies from one AIS to another in the same patient and among different patients; values of long T2 also vary with time, but without any correlation with the clinical state. In fact, no correlation was been established between relaxation times and clinical parameters. Quantitative MRI therefore enables a different approach to interpret MRI images; results suggest that several histobiochemical parameters play a role in the pathogenesis of an AIS and that MS is a dynamic and constantly evolving disease.

Adult↗

PubMed1991

Lesions of noradrenergic neurons in rats with spontaneous generalized non-convulsive epilepsy.

The role of noradrenergic neurons in the control of a spontaneous generalized non-convulsive epilepsy (GNCE) was investigated. In rats with genetic spontaneous absence seizures, we produced lesions using 2 neurotoxins: 6-hydroxydopamine (6-OHDA) and N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4). Lesions of noradrenergic neurons were made either in pups by neonatal 6-OHDA intraperitoneal (i.p.) injection (2 x 100 mg/kg) or in adult rats by i.p. administration of DSP4 (60 mg/kg) or bilateral microinjection of 6-OHDA in the locus coeruleus (LC) (4 micrograms/microliters, 2 microliters/side). Effectiveness of the lesions was controlled by measuring dopamine (DA) and noradrenaline (NA) contents in the brains. Neonatal 6-OHDA administration did not lead to any difference in seizures in adult animals, compared with control rats. DSP4 injections and LC lesions with local injections of 6-OHDA produced a transient increase of the seizures. Within one to two weeks, the seizure duration went back to prelesion levels. No seizure occurred when the same lesions were performed in non epileptic rats. These results suggest that NA is not involved in the genesis of this generalized non-convulsive epilepsy; they confirm that NA participates in the control of seizures in this model, but the rapid development of compensatory mechanisms shows that this control is not critical.

Animals↗

PubMed1991

[Mannosidosis type II].

Four out of 7 siblings born of non-consanguineous parents have presented psychomotor retardation, macrocephaly and facial dysmorphism associated in 2 of them with thoraco-lumbar kyphosis and in one of them with recurrent pulmonary infections which had resulted in death. Chromatography of oligosaccharides displayed a characteristic mannosidosis profile. In addition, D-mannosidase activity was very low in leucocytes and fibroblasts. The father and mother showed no clinical abnormality and had no pathological urinary oligosaccharide excretion, but their leucocyte and fibroblast D-mannosidase activity was reduced. These cases give the authors an opportunity to describe the clinical and biochemical features of mannosidosis, which in its type II enables the patients to survive into adulthood, and to underline the value of D-mannosidase assays to detect subjects with this anomaly.

Adult↗

PubMed1991

[Cerebellar cavernous angioma, cervical dystonia and crossed cortical diaschisis].

On four occasions since 1978, this 53 year-old woman presented with a right hemicorporal hypotonia, symptomatic of a hemispheric cerebellar syndrome. In 1981, she experienced the progressive development of a cervical dystonia. CT scan and RM scan showed a cavernous angioma in the right cerebellar hemisphere. The 18F-2-fluoro-2-deoxy-glucose PET scan revealed a right cerebellar and a contralateral cortical and striatal hypometabolism. This crossed cerebello-cortical diaschisis can be interpreted as a functional interruption of the cerebello-cerebral pathways. This case raises the question of the role played by a cerebellar lesion in the development of a focal dystonia.

Cerebellar Neoplasms↗

PubMed1991

[Is Cerebellar Soluble Lectin a major immunological target in multiple sclerosis?].

In a recent paper: (Zanetta J.P. et al., Lancet, 1990, 335, 1482-1484) the authors showed that antibodies against the mannose-binding protein Cerebellar Soluble Lectin (CSL) are present in the cerebrospinal fluid of most multiple sclerosis patients. Herein, the properties and roles of the molecule as they are currently understood are described; hypotheses suggested by the consistent presence of anti-CSL antibodies in multiple sclerosis patients are discussed.

Antibodies↗

PubMed1991

[Arthrogryposis and maternal myasthenia gravis. Risk of recurrence].

A 26-year old myasthenic woman whose disease had been in remission for more than 4 years gave birth, at the end of 2 induced pregnancies, to 2 stillborn infants with arthrogryposis. The presence of inherited antibodies directed against acetylcholine receptors most probably does not explain the diffuse retractions. This case illustrates the risk of recurrent foetal arthrogryposis after a first abnormal pregnancy in women with myasthenia gravis.

Adult↗

PubMed1991

[A differential diagnosis of quadricipital amyotrophy syndrome: bilateral disinsertion of the quadriceps tendon].

When it occurs bilaterally, disinsertion of the quadriceps tendons may suggest quadricipital amyotrophy syndrome. Questioning and physical examination of the locomotor system usually lead to a diagnosis of mechanical lesion involving the extensor mechanism of the knee. If necessary, this diagnosis can be confirmed by ultrasonography and MRI of the knee. A search for predisposing factors may result in a specific treatment, but only surgery provides functional improvement.

Aged↗