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N Mimassi

Publications and source records attributed to N Mimassi.

12 recordsLinked to original sources
PubMed2005

Time-course effects of centrally administered native urotensin-II on motor and cardioventilatory activity in trout.

Although in most vertebrate species urotensin-II (UII) is synthesized in neurons of the central nervous system, little is known regarding the physiological actions of UII in the brain. We have investigated the effects of intracerebroventricular (ICV) administration of synthetic trout UII (1, 5, and 50 pmol) on total motor activity (ACT), ventilatory frequency (VF), ventilatory amplitude (VA), and heart rate (HR) in the unanesthetized trout. ICV injection of UII increased ACT in a dose-dependent manner, and the maximal effect was observed at a dose of 5 pmol. At doses of 1 and 5 pmol, UII did not affect VF, VA, or HR. At the highest dose tested (50 pmol), UII not only increased ACT, but also significantly activated VF, VA, and HR. In contrast, ICV injection of synthetic trout angiotensin-II (5 pmol) did not produce any effect on ACT, VF, or VA, but sharply increased HR. These data provide the first evidence that UII can act centrally to induce motor activity in a nonmammalian vertebrate species.

Animals↗
PubMed2000

Enhanced sialyltransferase activity in B lymphocytes from patients with primary Sjögren's syndrome.

Despite the indisputable role of immunoglobulin (Ig)A in the pathogenesis of primary Sjögren syndrome (pSS), the causative abnormality remains largely unknown. As an extension of our report that IgA is oversialylated in this disease, the thrust of the present study was to measure the sialyltransferase (ST) activity in B lymphocytes. ST containing lysates of B cells from 17 pSS patients and 10 controls, were obtained using a combination of detergents, and incubated with affinity purified IgA that had been previously desialylated. The deposition of cytidine 5' monophosphate sialic acid (SA) by ST from B cells onto IgA was detected by two ELISA based upon the use of biotinylated lectins (Sambucus nigra agglutinin which is specific for alpha2-6 SA and Maackia amurensis which is specific for alpha2-3 SA). In parallel, the amount of SA on IgA from ten of the 17 patients and eight of the 10 controls was assayed using the same method. An excess of alpha2-3 and alpha2-6 SA on IgA was found in those patients with excessive activity of alpha2-3 and alpha2-6 ST. Thus, IgA hypersialylation in pSS patients may result from undue activity of ST.

Adult↗
PubMed2000

Cardiovascular actions of centrally and peripherally administered trout urotensin-I in the trout.

The cardiovascular effects of centrally and peripherally administered synthetic trout urotensin (U)-I, a member of the corticotropin-releasing hormone family of neuroendocrine peptides, were investigated in unanesthetized rainbow trout Oncorhynchus mykiss. Intracerebroventricular injections of U-I (5.0 and 12.5 pmol) produced a sustained increase in mean dorsal aortic blood pressure (P(DA)) without significant change in heart rate (HR). This elevation in P(DA) was associated with an increase in cardiac output, but systemic vascular resistance did not change. Intra-arterial injection of U-I (12.5-500 pmol) evoked a dose-dependent increase in P(DA), but in contrast to the hemodynamic effects of centrally administered U-I, the hypertensive effect was associated with an increase in systemic vascular resistance and an initial fall in cardiac output. HR did not change or underwent a delayed increase. Pretreatment of trout with prazosin, an alpha-adrenoreceptor antagonist, completely abolished the rise in arterial blood pressure after intra-arterial administration of U-I, which was replaced by a sustained hypotension and tachycardia. Trout U-I produced a dose-dependent (pD(2) = 7.74 +/- 0.08) relaxation of preconstricted rings of isolated trout arterial vascular smooth muscle, suggesting that the primary action of the peptide in the periphery is vasorelaxation that is rapidly reversed by release of catecholamines. Our results suggest that U-I may regulate blood pressure in trout by acting centrally as a neurotransmitter and/or neuromodulator and peripherally as a neurohormone functioning either as a locally acting vasodilator or as a potent secretagogue of catecholamines.

Adrenergic alpha-Antagonists↗
PubMed1984

[Pituitary adenoma secreting somatotropic hormone. Gigantism and peripheral neuropathy. A case].

Gigantism, an extremely rare condition, develops before puberty or in subjects in whom puberty is not yet completed. Hypersecretion of somatotropic hormone results in a tremendous surge in growth (our patient was 2.36 m tall). Among other clinical symptoms disabling peripheral neuropathy predominates and changes in nerve conduction velocity are not merely due to the increase in height. The increase in growth hormone concentrations combined with hypogonadotrophic hypogonadism with normal prolactinaemia is associated with peculiar cutaneous symptoms and with low levels of sex hormone-binding protein.

Adenoma↗
PubMed1984

Intrasellar cavernous hemangioma.

We present a very rare case of an intrasellar cavernous hemangioma mimicking, clinically and neuroradiologically, the presence of a nonfunctioning pituitary adenoma. It was possible to diagnose this benign, congenital vascular malformation only through a histological examination.

Adult↗
PubMed1982

[Prognostic value of the trigemino-facial reflex in severe post-traumatic comas].

The blink reflex (BR) study has been carried out on 40 severe head injury cases (average age 24.3 years). The recording was conducted several times between the 2nd and the 12th day and was repeated during the first month and beyond in prolonged comas. 23 patients did not respond even to high intensity stimuli. 17 patients displayed delayed and low amplitude latency responses: one of the components, early R1 or late R2 could be missing. The existence of a detectable focalized hemispheric lesion had no effect on the disappearance of the delayed lateral response. No BR was observed in mesencephalic, protubering comas and in 4 cases of subcortical and diencephalic comas. BR was observed in subcortical or diencephalic comas and in 5 cases of mesencephalic comas. The evolution of patients who did not display any electrical response during the first recording was unfavourable in 15 cases. Among the 5/8 remaining comatose cases, the BR was missing on the 2nd day and back on the 7th day. Among the 17 patients who displayed BR their evolution proved to be very favourable or favourable in 13 cases. In all the patients who survived beyond a month the response latencies proved normal, yet their amplitude was considerably lowered. The lack of BR is temporary but it is an element of unfavourable prognosis if it persists beyond a span of 8 days.

Adolescent↗
PubMed1982

Persisting recessus infundibuli and empty sella. Case report.

In a patient with thrombosis of the central retinal artery, plain skull radiographs showed an enlarged sella turcica and computerized tomography revealed ventricular dilatation. Neuroradiological examination demonstrated stenosis of the Sylvian aqueduct and an unusual type of empty sella due to intrasellar persistence of the recessus infundibuli and the presence of an intrasellar arachnoidocele. The former anomaly has been reported in only three cases; in none of them was it associated with the latter abnormality.

Arachnoid↗
PubMed1981

[Disabling segmental occlusion of the vertebral artery. Surgical treatment using a venous by pass from the external carotid to the C1-C2 portion if the vertebral artery (2 cases) (author's transl)].

The authors report the cases of two patients who were severely disabled due to signs and symptoms of vertebrobasilar insufficiency caused by unilateral segmental occlusion of one vertebral artery. The patency of the occluded vertebral artery beyond C3 was demonstrated by a faint angiographic injection through anastomic ascending cervical arteries which provided insufficient blood supply. The opposite vertebral artery was abnormal in both cases: a proximal kinking with intracranial atheromatous stenosis in the first and an atheromatous ostial stenosis in the second one. A venous by pass from the external carotid artery (end to end anastomosis) to the C1-C2 portion of the vertebral artery (en to side anastomosis) was performed through an incision from the tip of the mastoid process along the S.C.M. the division of which was unnecessary. Post operatively the signs and symptoms disappeared immediately. The stability of this result is attested by a follow up period of 13 months in the first case and 9 months in the second one. A control angiogram demonstrated a good supply to the vertebro-basilar system through the bypass, the excellent permeability of which was further confirmed by repeated Doppler ultrasound examinations. The indication of this technique is discussed.

Aged↗
PubMed1980

[A rare anomaly of the circle of Willis : infra-optic course of both anterior cerebral arteries: associated aneurysm of the basilar bifurcation (author's transl)].

A rare anomaly of the A1 portion of both ACA associated with a saccular aneurysm of the basilar bifudcation is presented. Based upon this case and eigth other cases in the literature, the anatomical and radiological features of the anomaly are precised : the anomalous artery comes from the internal carotid artery right over the cavernous sinus, very close to the origin of the ophtalmic artery; it rums medailly below the inferior aspect of the optic nerve, thus being projected under the plane of the optic canal on oblique angiograms; finally, it crosses the anterior edge of the optic chiasm up to the interhemispheric fissure. By itself the anomaly is asymptomatic but it should not be considered as a mere curiosity since it has most often been found associated with a variety of cerebral vasculature anomalies and in particular with encor more saccular aneurysms of the circle of Willis.

Brain↗