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Biomedical subjects

G Arnott

Publications and source records attributed to G Arnott.

At least 19 recordsLinked to original sources
PubMed1997

Developmental expression of parvalbumin by rat lower cervical spinal cord neurones and the effect of early lesions to the motor cortex.

Expression of calcium binding proteins (CaBPs), increasing neuronal activity and phases of synapse elimination are widely believed to be linked during development. We have employed immunocytochemistry to study the expression of the CaBP parvalbumin (PV) during the postnatal development of the lower cervical spinal cord and investigated how early lesions to the motor cortex, at the onset of corticospinal synaptogenesis, perturb the normal pattern of PV expression. This study confirms previous observations that in normal rats PV-like immunoreactivity is confined to large sensory afferents for at least 10 days postnatally (P10) and that the adult pattern of expression emerges from about P18 and involves mainly dorsal horn neurones. However, the study has also demonstrated a transient wave of expression in ventral horn neurones which reaches a maximum between P14-18 and declines thereafter. Unilateral lesions made at P7 to the forelimb motor cortex, which sends an almost completely crossed projection to the spinal cord, resulted in reduced neuronal expression of PV in the lower cervical spinal cord contralaterally at a range of ages (P14-31). The median ratio of PV positive neurones contralateral/ipsilateral to the lesion in spinal cord segments C7 and C8 was significantly lower (p < 0.01) at 56.0% (34.5-76.8 95% confidence limits, n = 14) than in sham operated controls (99.7%, range 93.7-113.6, n = 5). The lesion affected the transient wave of expression seen in ventral horn neurones during the third postnatal week as well as dorsal horn expression at older ages. We conclude that there is considerable plasticity in PV immunoreactivity during spinal cord development. PV is transiently expressed by ventral horn neurones at an age when movement control is functionally maturing. Early cortical lesions disrupt this transient phase of expression but also alter mature patterns of PV localisation. This suggests a critical role for corticospinal pathways in guiding maturation of segmental spinal cord circuitry.

Animals↗
PubMed1992

Juvenile distal cerebral ischemia: angiographic features. A study of 55 cases.

This study of juvenile distal cerebral ischaemia is based on 55 patients aged from 18 to 30 years. The authors describe the circumstances of discovery, as well as the clinical features and the course of the disease which may be severe and lead to non-resolutive neurological accidents and sometimes dementia. Paraclinical evaluation includes capillaroscopy, finger and toe pads biopsy (which clearly shows a pathological process with fibrocellular promontories narrowing the lumen of arterioles), and above all angiography which displays two typical signs: arterial narrowness and bands of peripheral ischaemia. In advanced forms of the disease angiography reveals classical signs of ischaemic lesions, but charateritically these are very distal. Associated abnormalities of the carotid siphon can also be found. Finally, positive CT scans show an isolated widening of the sulci which is fairly suggestive of the disease.

Adolescent↗
PubMed1990

[Spinal cord ependymoma: contribution of MRI using gadolinium].

In a case of panmedullary ependymoma, a rare tumour, MRI was performed before and after gadolinium injection. The latter clearly demonstrated the borders of the tumour. Throughout the procedure, neurophysiological exploration was carried out with recording of motor and somatosensory evoked potentials.

Adult↗
PubMed1988

[Guillain-Barré syndrome with favorable outcome in a case of recent human immunodeficiency virus infection].

An acute polyradiculoneuropathy occurred in a 30 years homosexual male. E.L.I.S.A. test and Western Blot showed recent infection by H.I.V. Besides, endogenous reinfestation by cytomegalovirus was found: high concentrations of specific IgG antibodies and presence of the virus in the blood. T4 helper cells were severely reduced, without any other sign of cellular immunity failure. None of the two viruses was found in the nervous biopsy. This Guillain-Barre syndrome with a subsequent cellular reaction in the CSF, is probably to be related to an immunoallergic mechanism. Brief increase of antibodies specific for HBsAg and Borrelia Burgdorferri and the beneficial effect of plasmapheresis, supported this view. Two months later, the patient showed superficial lymph nodes hyperplasia, without any other symptom of pre-Acquired Immuno-Depression Syndrome.

Adult↗
PubMed1986

False positive-false negative CT scan in late epileptic seizure: a meningioma-glioblastoma association.

A false-negative finding on initial CT is reported in a case of supratentorial glioma. This observation was peculiar because the first CT revealed a meningioma which might initially have been related to the clinical symptoms. The term false positive-false negative CT is proposed. The reasons for such CT failures are discussed. The accuracy of clues as to the localization of the glioma provided by EEG is emphasized.

Brain Neoplasms↗
PubMed1986

[11 cases of neuropathy induced by almitrine, of which one had optic neuropathy].

The only etiologic factor retained in 11 patients with sensory or sensory-motor neuropathy was almitrine therapy. In one patient there was in addition an optic neuropathy. The reduction in visual acuity in this patient coincided with the onset of the sensory-motor neuropathy of lower limbs after treatment with 100 mg/day of almitrine over a 2-year period. No other metabolic, inflammatory, toxic, vascular or immunologic cause was found. There was a moderate chronic respiratory insufficiency. Visual recuperation started one month after the arrest of almitrine treatment and was satisfactory 7 months later. The other 10 patients had neuropathy of limbs without visual disorders. Neuromuscular biopsy in one case showed lesions to be of the axonal type.

Aged↗
PubMed1986

[Spinal cord compression caused by dorsal disk hernia. Complication of Scheuermann's disease].

Association of Scheuermann's disease with a thoracic herniated disc compressing the spinal cord is rare but is clearly demonstrated in the case reported here. This confirms the non-fortuitous nature of this association also suggested by the analysis of published cases. The interest of spinal cord angiography and of surgery through a postero-lateral approach are emphasized.

Humans↗
PubMed1985

Acute spinal epidural abscess.

An anterolateral cervical epidural abscess occurred in the course of a septicaemia caused by Staphylococcus aureus. Early diagnosis, before permanent neurological signs developed, was provided by CT scan without myelography. Total recovery occurred with antibiotic therapy alone.

Abscess↗
PubMed1985

Anti-PHF antibodies: an immunohistochemical marker of the lesions of the Alzheimer's disease. Characterization and comparison with Bodian's silver impregnation.

An immune serum raised against paired helical filaments (PHF) was able to stain senils plaques (SP) and neurofibrillary tangles (NFT) specifically, the two characteristic lesions of the dementia of Alzheimer-type. This polyclonal antibody against PHF was characterized by immunochemistry and also compared with the classical Bodian silver staining. NFT and SP were observed where they were expected: in the fronto-temporal neo-cortex and hippocampus of Alzheimer-type patients, and also in hippocampus of non-demented elderly subjects. The pattern of SP visualized by the two methods was identical whereas NFT were not detected specifically by silver salts, specially in the nervous tissue where NFT were in discrete quantities. Since the preparation of the antigen is very easy and the resulting antibodies are specific, we conclude that this technique will be of considerable interest for routine neuropathological diagnosis. Finally, the properties of our anti-PHF antibody are compared with those reported in the literature. This antibody will probably be a good tool for the identification of the chemical nature of PHF components.

Adult↗
PubMed1985

Management of cavernous sinus meningiomas.

The management of intracavernous meningiomas remains controversial. The variety of methods of treatment reflects the difficulty of treating primary meningiomas of the cavernous sinus. Twelve personal cases and a review of the literature permit a choice between a direct surgical approach with or without radiotherapy, only radiation therapy or with no therapy. We think therefore that meningiomas of the cavernous sinus should nowadays be the subject of a surgical biopsy followed by radiotherapy according to their grading.

Adult↗
PubMed1985

[61 years' survival of Koch's bacillus in a closed focus. Disclosure in a case of spinal cord compression caused by sequelae of Pott's disease].

A 68 year-old woman presented with a spinal cord compression from an angular kyphosis due to Pott's disease at age 7. Clinical, radiological and pathological studies of the vertebral lesions did not demonstrate an evolutive lesion. However, culture yielded some viable Koch's bacilli. This bacteriologic confirmation 61 years later exemplifies the importance of host immunity reactions, that may prevent the development of KB, and the remarkable capacity of survival of the bacillus.

Aged↗