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Biomedical subjects

A Barret

Publications and source records attributed to A Barret.

At least 55 records · Page 3Linked to original sources
PubMed1986

Heparin half-life and sensitivity in normal subjects and in patients affected by deep vein thrombosis.

In some patients affected with deep vein thrombosis (DVT) it is necessary to administer large doses of heparin to achieve proper anticoagulation. To investigate the clinical relevance of this phenomenon, we studied the heparin half-life and the heparin sensitivity after a bolus IV injection of 60 i.u. kg-1 in seven healthy volunteers and eight DVT patients investigated on day 1 or 2 and again between day 10 and 20 of the heparin therapy. The heparin half-life, the in vitro and ex vivo heparin sensitivity, were comparable in the healthy volunteers and in the patients at both times of investigation. However, there were large interindividual variations in the controls and in the patients, not correlated to the levels of any coagulation factors. Thus, the heparin hyperconsumption phenomenon occasionally observed in a given patient reflected individual characteristics and was no value in the diagnosis of DVT.

Adult↗
PubMed1985

Does triiodothyronine influence the morphogenesis of fetal mouse mesencephalic dopaminergic neurons cultured in chemically defined medium?

Serum-free cultures of mouse mesencephalic cells were used for studying the influence of triiodothyronine (T3) on the morphogenesis of dopaminergic neurons. Supplementation of culture medium with T3 (10(-9) M) did not modify the number, but increased the size of the perikarya without affecting the neurite density of mesencephalic dopamine (DA) neurons. Furthermore, T3 had no effect on the uptake of [3H]DA in these cultures. These findings, taken together with previous results obtained with hypothalamic cell cultures, show that T3 affects the morphogenesis of mesencephalic DA neurons in a different manner than that of hypothalamus and that the perikarya size on the one hand, and the neurite elongation on the other hand, seem to be independently regulated by T3.

Animals↗
PubMed1985

Triiodothyronine stimulates the production of insulin-like growth factor (IGF) by fetal hypothalamus cells cultured in serum-free medium.

Grown in serum-free medium, dissociated cells from fetal mouse hypothalami release insulin-like growth factors (IGFs) and their binding proteins (IGF BPs) into the culture medium. Addition of triiodothyronine (10-12-10-8 M), which enhances neuron maturation, resulted in a significant increase in IGF concentration. By contrast, there was no significant effect on IGF BP. These results suggest a role for thyroid hormone in the control of IGF biosynthesis in nerve cells.

Animals↗
PubMed1985

[180 aorto-bifemoral bypasses for chronic occlusive arteritis].

In the authors' experience, 180 aorto-bifemoral by-pass grafts represent 42.4% of all reconstructive operations for aorto-iliac atheromatous disease performed between 1st January 1972 and 1st July 1983. 37% of the patients presented a threatened amputation and 38.8% had a walking distance of less than 100 metres. The immediate post-operative mortality (1st month) was 2.2% (4 patients). The 5 year survival, expressed according to the actuarial method, was 89% and the patency was 91%. The long-term functional deterioration was due to a progressive alteration of the distal vascular bed and to complications: false aneurysms (2.2%), prosthetic infections (1%), aorto-intestinal fistulae (2.2%), thrombosed prostheses (7.3%). 7 complementary femoro-popliteal by-pass grafts (4%) and 13 major amputations (7.4%) were required. The authors stress the value of performing end-to-end aortic anastomoses rather than side-to-end anastomoses. The anastomoses should be well isolated from the gastrointestinal tract. The patients should be rigorously followed post-operatively and any complication detected should be treated actively.

Aged↗
PubMed1984

Laminin promotes attachment and neurite elongation of fetal hypothalamic neurons grown in serum-free medium.

Laminin, as a coating or in solution, allows a rapid attachment of fetal hypothalamic cells in serum-free medium, and strikingly enhances the neurite network development. As compared to cultures grown on a fetal calf serum coating, cells remain in clusters and astrocytes become fibrous. Laminin was visualized by immunocytochemistry in non-neuronal cells. The number of laminin-positive cells was lower in cultures grown in serum-free medium than in those grown in serum-supplemented medium. In both culture conditions, their number decreases with time in vitro.

Animals↗
PubMed1984

[Angiography in aneurysmal disease].

The various angiographic techniques available are described, with emphasis on retrograde catheterization. Complications and results supplied by angiography in the investigation of aneurysms are outlined, and indications for the use of this method studied in relation to its use in 80 cases. Results of this analysis provide data on the reliability of angiography and enable definition of the choice of patients and the angiographic procedures that should be used.

Aneurysm↗
PubMed1983

Release of immunoreactive TRH in serum-free cultures of mouse hypothalamic cells.

Serum-free cultures of mouse hypothalamic cells were used as a model for studying TRH (thyroliberin) secretion in vitro. Supplementation of the culture medium with triiodothyronine, corticosterone and polyunsaturated fatty acids is necessary to obtain a substantial release capacity of TRH neurons. Under these conditions depolarization of the cells with 60 mM K+ results in a calcium-dependent release of immunoreactive TRH.

Animals↗
PubMed1983

Triiodothyronine enhances the morphological maturation of dopaminergic neurons from fetal mouse hypothalamus cultured in serum-free medium.

In dissociated hypothalamic cell cultures of 16-day mouse embryos, growing in chemically defined medium, the catecholaminergic neurons were identified by autoradiography after labelling with [3H]dopamine and by immunocytochemistry with an anti-tyrosine hydroxylase antibody. Using selective inhibitors of amine transport and radioenzymatic determination of amine levels in these cultures, we show that these neurons were mostly dopaminergic. The number of dopaminergic neurons identified by the two techniques increased between days 5 and 8 and decreased after 15 days in vitro. The same number of neurons were identified by autoradiography and by immunocytochemistry and consisted of fusiform and multipolar neurons. The proportion of both types remained steady until 15 days in vitro. Under these conditions, the addition of triiodothyronine (10(-9) M) at the initiation of the culture increased the size but not the number of dopaminergic neurons after 8 days in vitro. Furthermore, triiodothyronine significantly increased the dopaminergic neurite length and arborization. This morphological effect of triiodothyronine was associated with an increase of 35% in [3H]dopamine uptake. Our study shows that hypothalamic dopaminergic neurons are responsive to triiodothyronine which acts as a maintenance or trophic factor having an effect on neurite extension and arborization.

Animals↗
PubMed1983

[Thrombocytopenia induced by heparin. Apropos of 10 cases].

The authors report ten observations of thrombocytopenia induced by heparin complicated with two arterial thrombosis and four deep venous thrombosis. Two deaths and two amputations are to mention. This retrospective study leads to a review of literature: this iatrogenic disease, which frequency is variously estimated, has no relation with the dose and the mode of administration of Heparin. It's mechanism might be immuno-allergic. It's diagnosis depends mainly on the repetition of platelet numerations at the outset period of treatment, and on the rapid and lasting climbing of platelet countings when heparin is stopped. This uncommon and unforeseeable complication indicates to stop Heparin and to start K antivitamin's if necessary.

Adult↗
PubMed1982

[Outcome of patients undergoing surgical plication of the inferior vena cava].

In a group of 70 patients, 40 undergoing the insertion of a Mobin-Uddin umbrella and 30 the placing of an Adams-DeWeese clip, the authors noted a 6% recurrent embolism rate within a follow up period of 14 months to 5 years. This was fatal in 1.5% of cases. There was 10.9% recurrent phlebitis and 9.4% sequelae of severe stasis. Mobin-Uddin umbrellas gave the most complications and should be reserved for the worst cases. Indications for the Adams-DeWeese clip can be extended to surgical patients with a thrombo-embolic risk and to dangerous clots visualised by phlebography.

Aged↗
PubMed1980

[Limits of platelet aggregation tests for investigating thromboses (author's transl)].

Three methods--spontaneous aggregation, ADP-induced aggregation and levels of circulating platelet aggregates--were used to test for platelet hyperaggregation in 87 adult patients divided into three groups. Group A comprised 26 patients with severe arterial diseases, including cerebral vascular accidents (16) and peripheral thrombosis (10) ; group B consisted of 31 patients with venous conditions, including deep phlebitis (22) and recurrent thrombo-embolic disease (9) ; group C, which served as control, comprised 30 patients with various non-vascular disorders. Spontaneous aggregation and enhanced reactivity to ADP correlated well with each other and were more frequent in patients with vascular diseases. However, one-third of patients in group C had pathological results, while one-third of patients in groups A and B had normal results, independently of any clinical particularity or therapeutic regimen. There were no significant differences between the three groups with regard to circulating platelet aggregates. These tests, therefore, appear to be of statistical and epidemiological interest, but of questionable practical value.

Adenosine Diphosphate↗
PubMed1980

[Return to work after reconstructive arterial surgery (author's transl)].

The authors studied the conditions of the return to work of 65 patients, with a maximum age of 55 years, after reconstructive arterial surgery. Of the 51 patients who were working at the time of the operation, 46 (90.2%) had started working after an average period of 97 days, but only one of the patients who were no longer working started work after the operation. If the nature and more especially the site of the operation is analyzed, the highest level of return to work was after aorto-iliac surgery (96,4%), with a lower level (81%) after femorotibial operations. In a small group of 6 patients operated upon for aneurysms (of which 5 were aneuryms of the abdominal aorta), 4 had started work again, but after a longer period of 4 months on average. These results are compared with those obtained by a British team in Newcastle (Waters, Proud, and Chamberlain) who conducted a similar study in 1977. These overall results prove that reconstructive arterial surgery is favourable from the social and occupational point of view, as very large proportion of the operated patients continue working, and some of them start work again after having stopped their occupation before the operation.

Adult↗