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Biomedical subjects

M Baulac

Publications and source records attributed to M Baulac.

At least 109 records · Page 6Linked to original sources
PubMed1987

[Intracerebral transplantation of oligodendrocytes in mice].

We describe in this paper experiments in which oligodendrocytes (from newborn mouse, human embryonic brain, or isolated from adult rat brain) have been transplanted into the brain of the newborn mouse. Experimental conditions (Shiverer model) allowed the detection of myelin formed by transplanted oligodendrocytes into the Shiverer brain. The transplanted oligodendrocytes have been shown to survive, migrate over long distances and myelinate host axons. The maturation of transplanted oligodendrocytes depends upon the age of the brain tissue in which they differentiate.

Animals↗
PubMed1986

[Dopaminergic innervation of the parahippocampal and hippocampal regions in the rat].

In spite of extensive investigations of the rat's meso-cortico-limbic system, the dopaminergic (DA) innervation of the hippocampal formation (HF) has not heretofore been visualized by histochemical techniques. However pharmacological and biochemical studies strongly suggested its existence. We used tyrosine-hydroxylase (TH) as an immunocytochemical marker of DA neurons in rats in which the noradrenaline cortical innervation was previously destroyed by neurotoxins. The absence of noradrenergic axons was routinely controlled with dopamine-beta-hydroxylase immunocytochemistry. TH-positive axons, thus DA axons, reach the HF primarily through the fimbria in which they occupy a specific lateral sector. They innervate the ventral and caudal parts of the HF, the subiculum and the adjacent CA1 hippocampal field being the main targets. This DA terminal field in the HF, matches with the area projecting toward the nucleus accumbens. Thus the hippocampo-striatal projections which represent a link of functional importance between the limbic and central motor systems might be modulated by the dopaminergic meso-cortico-limbic pathway. The present immunocytochemical study confirms the very dense innervation of the entorhinal cortex (EC): DA axons are organized in dense fiber islands and occupy primarily the superficial layers (I-II-III). Da innervation predominates in the lateral part of EC, which is the site of multimodal cortical afferences and therefore relays information between the whole neocortex and the hippocampus. Thus the DA system could play an important role of modulation on hippocampal and parahippocampal functions.

Adrenergic Fibers↗
PubMed1986

[Intracranial artery stenoses 44 years after craniofacial radiotherapy].

A 58 year-old patient experienced several ischemic strokes in the carotid arteries territories. History revealed a nasal epithelioma, for which he had received, at age 14, an irradiation through an anterior field (5500 rads), and two lateral fields (4550 rads each). He had a nasofacial atrophy as apparent sequellae. Angiograms showed stenoses of the cavernous portion of both internal carotid arteries and of the proximal portion of the left anterior cerebral artery. The ophthalmic arteries were narrowed and irregular. Despite the very long delay and the patient's age (that of common atherosclerosis) and the lack of specificity of the lesions, the relationship between the arterial lesions and radiotherapy was accepted: the site of the arterial lesions corresponded to that of irradiation; other carotid segments, and particularly the bifurcations of the common carotid arteries, appeared normal on angiograms. The X-rays dose delivered in the region of the Willis arterial circle had been very high. A review of the rare reported cases of intra-cranial post-irradiation arteriopathy is presented.

Brain Ischemia↗
PubMed1986

[Motor neglect of thalamic origin].

The clinical picture of thalamic motor neglect is identical to those of motor neglect in general, the major symptom of which being an underutilization of one side of the body in the absence of sensory-motor defect. Several thalamic nuclei can be implicated on the grounds of pathological and experimental data, most frequently the ventro-lateral nucleus. The prevalence of left neglect is not so obvious in the case of thalamic than in the case of other sites of lesions. Motor neglect appears as a disorder in the triggering of the brain structures network which program and prepare movement in several circumstances; attentional tasks are only a particular circumstance. Some thalamic nuclei are the site of hypoactivity in the case of frontal motor neglect in the monkey, as shown by anatomical and functional studies; this emphasizes the strong participation of thalamus to the motor network, the dysfunction of which can induce a motor neglect.

Attention↗
PubMed1986

Postmortem studies on posthypoxic and post-methyl bromide intoxication: case reports.

In two cases of action myoclonus following hypoxic or shock encephalopathy, neuropathological examination disclosed mild or moderate scattered changes involving thalamus, griseum centrale mesencephali, and nucleus centralis superior. Other areas were affected only in one of these cases (striatum, nucleus subthalamicus or hippocampus, nuclei pontis, and cerebellar cortex). In another case (an alcoholic patient), the changes, which involved only corpus mamillare and thalamus, were those of Wernicke-Korsakoff encephalopathy. In one case of oscillatory myoclonus following septic shock, there were marked cerebellar changes involving deep nuclei and mild abnormalities in the thalamus and inferior olive. The last case of action myoclonus following acute methyl bromide intoxication was characterized by marked changes in the inferior colliculi and moderate or mild abnormalities of thalamus, griseum centrale mesencephali, nucleus centralis superior, nucleus reticularis tegmenti pontis, nuclei pontis, and dentatus. The findings are compared with the data of seven previously reported neuropathological examinations in action myoclonus following hypoxic encephalopathy.

Adult↗
PubMed1985

Morphological evidence for a dopaminergic terminal field in the hippocampal formation of young and adult rat.

We have visualized the dopaminergic innervation of the hippocampal formation of the rat using two morphological methods: (1) tyrosine hydroxylase immunocytochemistry on noradrenaline-depleted animals and (2) fluorescence histochemistry after the uptake and storage of dopamine on hippocampal slices in vitro. The noradrenergic hippocampal terminal fields were destroyed by neonatal neurotoxin pretreatment and the validity of the lesion checked by the absence of dopamine beta-hydroxylase immunoreactivity. As observed on early postnatal ages, dopaminergic axons reached the hippocampal formation through the fimbria and the alveus, but also through the supracallosal bundle and the ventral amygdaloid area-entorhinal cortex. The temporal (ventral and caudal) part of the hippocampal formation received the bulk of the dopaminergic innervation whereas no fibers were observed in the septal pole. Very few positive axons were visualized in the hilus of the gyrus dentatus and CA3 field, only near the temporal pole. CA1 field (stratum oriens) was innervated throughout its ventral part. The most innervated area was the ventral part--especially the deep layers--of the subiculum, in particular the prosubiculum. The dorsal part of the subiculum displayed some positive axons, although to a lesser extent. The pre- and parasubiculum contained a few positive axons. In addition, some immunoreactive axons were observed in the anterior hippocampal continuation and the indusium griseum. The ventral junction prosubiculum-CA1 field appears to be the main target area for the hippocampal dopaminergic innervation. It is interesting that the same areas are characterized by their projections to the nucleus accumbens which receives dopaminergic afferents. Thus, the hippocampostriatal projections, that represent a link between the limbic and central motor mechanisms, could be under dopaminergic influence.

Age Factors↗
PubMed1984

Pure psychic akinesia with bilateral lesions of basal ganglia.

Three patients showed dramatic psychic akinesia after recovery from toxic encephalopathy. They had no or only mild motor disorders. The spontaneous psychic akinesia was reversible when the patient was stimulated, as if there was a loss of self psychic activation. Intellectual capacities were normal. Two patients had stereotyped behaviours resembling compulsions. In all patients CT cans showed bilateral lesions in the basal ganglia, mainly within the globus pallidus.

Adult↗
PubMed1984

[Pure spinal cysticercosis. Note on the cerebrospinal fluid].

A patient from Benin experienced bilateral sciatic pain, followed by a progressive sensori-motor defect of the lower limbs. Five years after, he displayed symptoms and signs of a thoracic spinal cord compression, but no definite level could be determined. Myelography showed numerous intrathecal cysts from the cauda equina to the cervical cord. The diagnosis of cysticercosis was made by examination of the cysts removed after lumbar laminectomy. The search for another localisation of the parasite was negative. Repeated examination of cerebrospinal fluid (CSF) showed the presence of eosinophils, a high protein concentration, and a local synthesis of immunoglobulin G with an oligoclonal profile on electrophoresis. An accidental cyst punction revealed a fluid with protein migration in the alpha, beta and gamma ranges and a local synthesis of immunoglobulin A. Treatment with Praziquantel was uneffective.

Cysticercosis↗
PubMed1983

The loss of motorneurons corresponding to specific muscles in the wobbler mutant mouse.

The spinal motorneuronal pools specific to a peripheral muscular territory were studied in the wobbler mutant mouse, with the use of retrograde transport of horseradish peroxidase, which was injected into the musculo-cutaneous nerve and into the distal part of the sciatic nerve. Counts of labeled cells showed that the mean percentage of surviving motorneurons was 48.4% in the case of the musculo-cutaneous nerve and 83.6% in the case of the sciatic nerve. The cell loss was not found to be different in old compared to young mutants, suggesting that motorneuron degeneration is an early event in the course of the disease.

Animals↗
PubMed1983

Postnatal development and cell death in the sciatic motor nucleus of the mouse.

Motoneurons of the sciatic nerve were studied in the lumbar cord of the mouse, at various postnatal stages, 1-3 days, 6-7 days, three weeks, and 2-3 months. Horseradish peroxidase (HRP) was applied at the cut end of the distal sciatic nerve, and, after retrograde transport, transversal and longitudinal histological sections of the cord were made in order to compare various features of the motor pool such as cell grouping, position in gray matter, cell number, cell size, and gross dendritic patterns. As early as birth, sciatic nerve motoneurons were grouped in a longitudinal column in the homolateral gray matter. No labelled cells were found outside the column either ipsilaterally or contralaterally. The location of the column was constant throughout postnatal development, encompassing the same spinal root levels and occupying the same position in the gray matter, the lateral portion of the ventral horn. Cell volume showed a 4-5 fold increase. Dendrites were not visible at the early stages and became labelled at 2-3 months. The neuropil also displayed a 4-5 fold increase, causing considerable spacing of the motoneurons. Histograms of cell body volume showed the progressive differentiation of the initially uniform motoneuronal pool in different sub-populations. In each experimental animal, labelled cells were counted in all histological sections and, for statistical comparison, the value was corrected for mean cell size. A 31% decrease in the number of labelled cells was observed between birth and 2-3 months. The rate of cell death was not constant, since 17% disappeared during the first week and 14% thereafter. The 31% decrease was lower than that observed in previous studies in the rat, 50-80%. The difference in species may explain this discrepancy, however, technical differences must also be invoked. In these studies, HRP was injected into the biceps brachii muscle. An overestimation of cell death is possible with this technique because postnatal changes of the axonal endings permit easier HRP uptake in immature muscles than in mature muscles. The cut nerve technique however by-passes the axonal endings.

Aging↗
PubMed1983

[Morphometric study of the piririform aperture].

The piriform aperture or enter orifice of the nose may be too small, creating an obstacle for inspirated flow. The functional disturbance realised has been described as the "syndrome of aspiration of the nasal ala". The present study has been made on 100 skulls. We have measured the dimensions of the piriform aperture, calculated a "form index" and searched a correlation between the morphology of this aperture and the morphology of the skull. It appears that the form and the dimensions of the piriform aperture depend on the ethnic origin and not on the cranial anthropologic type. The surface of the piriform aperture can be calculated on a radiological examination. The dimensions and the form of the piriform aperture must be correlated with the morphology of the nasal pyramid. Knowledge of the dimensions of the piriform aperture is useful for diagnosis of functional rhinologic disturbances.

Anthropology, Physical↗
PubMed1982

[Loss of psychic self-activation. Compulsive activity of obsessional type. Bilateral lenticular lesion (author's transl)].

After a carbon monoxide intoxication with coma of short duration, a 25 years-old man sustained a demential state and during the first weeks, a mild extrapyramidal syndrome. One year later, the mental state had progressively improved, although with a severe anterograde amnesia but the clinical picture had become unique. Let without external stimulation, the patient remained inert without any activity, often lying on his bed but not sleeping. He had lost any initiative. At the opposite, if he was stimulated, his physical, intellectual and affective performances were nearly normal, verbal fluency remaining however poor. Psychic self-activation appeared to be lost but psychic possibilities after external stimulation were nearly normal. When inactive, the patient was occupied with a mental compulsive activity. C.A.T. showed bilateral necrotizing lesions in the globus pallidus. The present case is very similar to a previously reported one. (D. Laplane et al., Rev. Neurol., 1981, 137 : 269-276) in which bilateral lenticular lesions produced the same syndrome. The pallidal area seems to play a determinant role in the processes of self-activation of psychic life.

Adult↗
PubMed1981

Bilateral infarction of the anterior cingulate gyri and of the fornices. Report of a case.

A 70-year-old woman had complex behavioural changes of sudden onset. The symptoms consisted of indifference, docility and inappropriate urination, but predominantly in a lack of attention. She was unable to maintain the attention necessary to perform a goal-directed activity and she was distracted by any stimulus, such as a sound, an object, or a word, which might induce behaviour irrelevant to the preconceived activity. She also exhibited confabulatory-amnestic syndrome. Neuropathological examination of the brain revealed infarcts in th territories of both anterior cerebral arteries. The rostral part of the anterior cingulate gyrus (Acg), small areas of the adjacent medial prefrontal cortex, and the underlying white matter were destroyed bilaterally. Infarction involved the deep territory of the left anterior cerebral artery, with a bilateral lesion of the fornices. This cingulate damage was more restricted than the Acg lesions reported in some cases of akinetic-mutism, which extended more caudally, but was presumably larger than the lesions created in psychosurgery. The impairment of attention was analyzed according to the possible roles of the cingulate and of the fornix lesions as causing a dysfunction between the frontal lobes and the hippocampal formations.

Aged↗
PubMed1981

[Dopaminergic receptors on lymphocytes in idiopathic Parkinson's disease (author's transl)].

(3H) spiroperidol binding has been measured in lymphocytes from patients with Parkinson's disease and age matched healthy volunteers. A dramatic decrease (73 p. 100) in the number of binding sites Bmax without any variation of the affinity KD has been observed in untreated Parkinsonian patients. This decrease in Bmax is linearly correlated with the degree of disability of the Parkinsonian patients (r = 0.891, p less than 0.001). This decrease appeared to be relatively selective since no variation was observed with patients suffering of other neurological disorders. The possible relationships with the number of striatal dopamine receptors are discussed. With levodopa therapy, Bmax had the same mean value as in control subjects. This result means that levodopa induces an increase in lymphocyte binding sites and in five patients this increase could be observed by study before and during drug administration. In some severely disabled patients who had received levodopa for several years, Bmax was found much lower or higher than the mean value, which may suggest different interpretations of drug unefficiency.

Adult↗
PubMed1981

[Organization of pectoral muscle motor neurons in the rat. Contribution to the study of the axillary arch (Achselbogen)].

In spite of their role of the forelimb activity, the organization of the mammalian pectoral muscles remains unclear. In order to get more information, we have studied, qualitatively and quantitatively, the motor pools of the various pectoral muscles in the rat (musculus pectoralis major, musculus pectoralis minor and musculus panniculus carnosus). The method applied was the retrograde transport of horseradish peroxidase by the peripheral nerves supplying the various muscles. The results provided the precise localization within the ventral horn of the motor neurons from the pectoral muscles which were all in the most ventral part of the gray matter. Three distinct motor pools were observed, which confirms the functional identity of each muscle. The motor neurons of m. panniculus carnosus exhibited some particularities. They were 4 times more numerous than those from m. pectoralis major, they occupied the whole ventral edge of the ventral horn, from its medial part to its lateral tip. The cell size was different from that of the other muscles. These results were discussed, according to the role of this muscle, which links the forelimb to the whole trunk. In mammals, m. panniculus carnosus constitutes, with musculus latissimus dorsi, the axillary arch (Achselbogen). A small area of overlapping between the motor pools of these two muscles was observed. It was suggested that the muscular fibers from the axillary arch were innervated by the same, well-defined spinal area, independent of the muscle from which they originate.

Animals↗