Search PubMed⌕ Search

Biomedical subjects

S Blond

Publications and source records attributed to S Blond.

At least 91 records · Page 5Linked to original sources
PubMed1987

[Lhermitte-Duclos disease. Apropos of a case].

The authors report a case of dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease). This woman's first neurosurgical admission was in 1970 at the age of 15 years. Hydrocephalus related to aqueduct-stenosis was diagnosed and a ventriculo atrial shunt was inserted. Ten years later, she underwent partial resection of a third ventricle tumor which was identified as a pilocytic astrocytoma. In 1986, computerized tomography revealed a non-enhancing left cerebellar mass lesion. Surgical excision was performed, and pathological examination disclosed dysplastic gangliocytoma of the cerebellum.

Adolescent↗
PubMed1986

Kinetic characterization of early intermediates in the folding of E. coli tryptophan-synthase beta 2 subunit.

This report describes the use of fluorescence energy transfer between an intrinsic energy donor (tryptophan 177) and two chemically added acceptors to study intermediates in the folding of the beta 2 subunit of E. coli tryptophan-synthase. Two early folding steps are thus identified and characterized. One is very rapid (its rate constant at 12 degrees C is 0.02 sec-1) and corresponds to the folding of the N-terminal domain into a structure whose overall features approximate well those of the native domain. The second step is somewhat slower (its rate constant at 12 degrees C is 0.008 sec-1) and involves a conformational rearrangement of the N-terminal domain brought about by the interactions between the N- and C-terminal domains within a monomeric beta chain. This brings to five the number of intermediates which have been identified and ordered on the folding pathway of the dimeric beta 2 subunit.

Escherichia coli↗
PubMed1985

Kinetics and importance of the dimerization step in the folding pathway of the beta 2 subunit of Escherichia coli tryptophan synthase.

During its folding, the polypeptide chain of the beta 2 subunit of Escherichia coli tryptophan synthase (L-serine hydrolyase (adding indole) EC 4.2.1.20) undergoes dimerization. To decide whether this dimerization precedes or follows the formation of the native, functional, tertiary structure of the polypeptide chain, the kinetics of renaturation of beta 2 are studied by monitoring both the regain of native conformation and the dimerization. Dimer formation is followed by the increase of the fluorescence polarization, or by energy transfer between a fluorescence donor and a fluorescence acceptor, which occur upon association of adequately labelled beta chains. Renaturation is followed by the regain of functional properties of beta 2, i.e. its ability to bind pyridoxal-5'-phosphate or to form a fluorescent ternary complex with this coenzyme and L-serine. It is shown that for beta 2 the dimerization obeys first-order kinetics, presumably because it occurs rapidly after a rate-limiting isomerization of the monomer. The dimerization is followed by another isomerization, taking place within the dimer, which leads to the formation of the pyridoxal-5'-phosphate binding site. Still another, slow, isomerization reaction involving the F1 (N-terminal) domain completes the renaturation. With a modified form of beta 2 (trypsin-nicked beta 2) where this isomerization of F1 can be made to occur before the dimerization, the dimer is also shown to appear before the functional properties. It is concluded that a non-native dimer indeed exists as an obligatory intermediate on the folding pathway of nicked beta 2 and of beta 2, and that interdomain interactions are needed to force the polypeptide chains into their native conformations.

Energy Transfer↗
PubMed1985

Cryptic vascular malformations diagnosed by stereotactic biopsies--a preliminary study.

A series of 14 cryptic vascular malformations (CVM) deeply situated or localized in functional cortical areas were diagnosed by serial stereotactic biopsies. No history was suggestive of hemorrhage, despite a substantial hematoma being evacuated during biopsy procedures in 4 patients. Retrospectively, CVM without hematoma were found to have certain characteristics that should raise the suspicion as to the correct diagnosis. At the time of discharge from the hospital, only 1 patient had mild aggravation of a preexisting motor deficit, which further improved. Serial stereotactic biopsies provided the required histological diagnosis with relatively low risk.

Adolescent↗
PubMed1985

[Acute pseudobulbar syndrome. Bilateral infarction of the junction of the internal capsule with the corona radiata].

A 33 year-old hypertensive woman presented with a pure, acute, pseudobulbar palsy, two years after a right transient facio-brachial hemiplegia. C.T. scan showed two areas of low density projecting over the junction of the internal capsule with the corona radiata, at the external border of the lateral ventricles. They involved the territories of both posterolateral choroidal arteries, at the junction with those of the external lenticulostriatal arteries. Clinical data, clinico-pathological correlations in pseudobulbar palsies, and new concepts about the corticobulbar tract anatomy are discussed with evidence from this case.

Acute Disease↗
PubMed1985

[Stereotaxic treatment of expanding cysts in craniopharyngiomas by endocavitary beta-irradiation (Re-186; Au-198; Y-90)].

The authors report the results of 17 intracystic injection of colloidal 186 rhenium, 2 colloidal 198 gold, and 1 colloidal 90 yttrium for endocavitary treatment of 18 cystic craniopharyngiomas (16 pts during a period ranging from January 1975 till July 1982. Follow-up studies ranging from 12 to 72 months (m: 36 m) revealed that all craniopharyngiomas cysts were effectively treated with cessation of fluid formation, progressive shrinkage of the formerly expansive cysts, and finally cyst obliteration in 75% of the cases. No early or late side-effects were observed during the entire observation period. Late reexpansion of one craniopharyngioma cyst, observed at 11 months, was successfully treated by a second injection. Leakage of colloid isotope into the CSF spaces during the "test" or "therapeutic" injections occurred in 18% of the global number of injections, however no clinical complications were observed. On the basis of a clinical dosimetric study a 30 000 rads wall-dose, not exceeding 40 000 rads is actually considered as the safer dose for endocavitary treatment of craniopharyngioma.

Adolescent↗
PubMed1985

[Stereotaxic biopsies (SB) of intracranial neoplasms. Considerations apropos of 3,052 cases].

On May 12th 1984 a meeting on stereotactic biopsies of intraencephalic lesions has been held in Marseilles. All French Neurosurgeons and Neuropathologists involved with this technique were present. This report presents, in one hand, the result of an investigation on 3 052 BS and, in the other hand, the synthesis of discussions held on the limits and dangers of the BS, morphology of the biopsy instrument, means of the definition of the target and the microscopic histologic technics and results.

Biopsy, Needle↗
PubMed1985

[Acute transient Korsakoff's syndrome caused by hematoma of the floor of the 3rd ventricle].

A forty four year-old woman had had an amenorrhea-galactorrhea syndrome for 3 months when a Korsakoff's syndrome with headache suddenly appeared. Neuroradiological investigations revealed a hematoma involving the anterior part of the IIIrd ventricle. After a short period of neurogenic hypernatremia the lesion disappeared with the development of a spontaneous ventriculocisternostomy. Simultaneously, the Korsakoff's syndrome decreased until it went off almost completely, but a diabetes insipidus appeared and the hyperprolactinemia remained unchanged. Four years later, those are the only symptoms which are still present. This case, particular by its aetiology and evolution, illustrates well the possibility of functional Korsakoff's syndromes.

Acute Disease↗
PubMed1983

[Familial forms of intracranial cavernous hemangioma. Apropos of 5 cases in 2 families].

The authors report five cases of cavernous hemangioma belonging to two families. In the first family, an 8 year old child was operated on in 1970 for a left frontal location. His mother, aged 39, was operated on in december, 1981, with stereotaxic approach, for two locations: one was frontal location, the other one was in the pineal region. Among the second family, a 21 year old woman was operated on in december 1976, for a cerebellar cavernous hemangioma. Her sister, aged 18, presented with subarachnoid hemorrhage in january 1980. C.T. scan showed a right temporal high attenuation area. This patient was not operated on. The aunt to those two sisters was operated on in october, 1981, for a left temporal cavernous hemangioma. Those five cases represent about half of the intracranial cavernous hemangiomas operated on in the Lille Neurosurgery Department since 1967. Even, unusual, the familial occurrence of this affection must be admitted. It shows a nosological interest, but also allows prevention by searching and surveying the asymptomatic cases, or genetic evaluation of disease risk.

Adult↗
PubMed1983

[Extradural spinal hematoma without traumatic bone lesion. Apropos of 9 cases].

Extradural spinal hematomas observed in 9 cases over a period of 11 years developed in the absence of blood coagulation disorders in 3 cases, during anticoagulant therapy in 5 cases, and during the course of a megaloblastic anemia in one patient. The presence of marked associated myelomalacia was confirmed at postmortem in one case. Etiopathogenic factors remain obscure, particularly in spontaneously developing forms, and careful histologic examination of all clots is necessary to determine possible vascular malformations at the origin of the hematoma.

Adult↗
PubMed1982

[Total right hemispherectomy: neurophysiological study after twenty-six years].

Twenty-six years after a total right hemispherectomy for tumor when thirteen years old, a right-handed patient presented with disturbances of equilibrium, urinary incontinence, and a marked reduction in motor impulses, in spite of a subnormal intelligence quotient (0.85). Computed tomography examinations suggested the presence of a normal pressure hydrocephalus. However intracranial pressure monitoring and isotopic and cerebrospinal fluid perfusion tests showed the absence of any cerebral obstruction, and free communication between the cerebral and spinal spaces, though intracranial volume capacity accommodation was greatly reduced. Clinical examination demonstrated good quality sensory appreciation by the left half of the body, the possibility of detecting an object in the visual hemifield supposedly blind, and perfect location of a sound source. Somesthetic evoked potentials were studied by stimulating the median nerve in the left and right wrist regions. Left hemisphere evoked potentials from a contralateral stimulus, were of normal latency, amplitude and morphology, the response to an ipsilateral stimulus also presenting an early potential component (N 26 starting at N 21). This exceptional finding in a hemispherectomized patient could be related to activity of the spinoreticulothalamic tracts in the lemniscal or extralemniscal systems. Auditory function tests demonstrated perfect stereoaudiometry and the quality of perception during dichotic listening tests. Auditory evoked potentials in the brain stem included only minor functional-type anomalies, with slightly increased latencies in the pons on the left, and the mesencephalon and pons on the right. The presence of a bilateral wave VI was related to activity of the median geniculate pathway. Visual function tests showed good quality left photomotor reflexes and positive object detection in the anopsic hemifield. Results of these tests were reproducible during the same examination and after an interval of several months. The relevant literature is reviewed.

Adolescent↗
PubMed1980

[Fornix and septal tumor (author's transl)].

This study attempts to supply to internists exact and specific references to succeed early to the diagnosis of "fornix and septal tumor' with or without callosal extension. After a short anatomical recall, a neurophysiological study of the fornix permits to the authors to explain about the physiology of the memory and to place the function of this commissural formation from the classic hippocampal and mammillian theory and from more recent fundamental ideas about the part of thalamus. The evocation of the function of corpus callosum in the harmony of the thought and movements shows many deep neuronal circuits necessary to a normal activity. These data emphasize the specific neuropsychological semiology of these tumors at the "incipiens' period before that appear the symptoms of intracranial hypertension or invading and adjoining structures. Thus, it is possible to describe a syndrom of the anterior middle line that is different of a frontal semiology appeared at a more late period. It is necessary to show the minor or neglected psycho-organic disorders and to scan by a neuropsychological searching examination. The specialized and complementary explorations have been, during a long time, difficult to explain. Still, the C.T. scanner reduces these difficulties and will be realize at the least doubt. In the Lille's neurosurgery department, we recall the importance of the deep phlebogram's study during the angiographic examination and we define diagnosis tests. The ventricular explorations are always good but more exact if a stereotactic methodology is used. This one permits to specify the mass due to a lesion, the histological constitution without forgetting its therapeutic action. These efforts, in the diagnosis approach, are justified by the anatomo-pathological study that proves the great percentage of benign tumors. The operative technics is clearly defined: surgical approach, essential structures reference, definition of the tumor's limits with tela choroïda and the third ventricle, surgical excision as complete as possible. The therapeutic results depend on the histology and extension of the tumor. Their benign composition during a long time and the inefficacy of the radiotherapy, except sometimes, plead in favour of a surgical treatment. This one is more easier that it is earlier.

Adolescent↗