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Biomedical subjects

P Desnoyers

Publications and source records attributed to P Desnoyers.

At least 19 recordsLinked to original sources
PubMed1995

Hospital-based alcohol and drug specialty consultation service: does it work?

The goals of this report are to describe the development of an inpatient-based alcohol and drug abuse consultation service in a university hospital. At the University of Wisconsin Hospital, we collected data on baseline diagnosis, health services, and costs for inpatients who received such a consultation in 1992-1993 (n = 1,098, 3.5% of all admissions). Follow-up interviews were conducted on a sample of 175 subjects. At the initial assessment, 65% were nicotine dependent, and 50% met criteria for alcohol dependence, 19% for alcohol abuse, 13% for alcohol and drug abuse/dependence. The average cost to patients for a consultation was $220. At the 6-month follow-up interview (n = 175), 42% of the subjects reported complete abstinence, 70% reported reductions in use, and 56% participated in an alcohol and drug treatment program. An inpatient-based alcohol and drug abuse consultation service provides a critical benefit that has not previously been offered in most academic medical centers.

Adolescent↗
PubMed1989

[Dermatan sulfate and the prevention of experimental venous thrombosis].

Although the specific anticoagulant activity of dermatan sulphate is seventy times less than that of standard heparin, its venous antithrombotic activity, tested on a great number of experimental models, appears at gravimetric doses which are only seven fold higher. This antithrombotic activity is not correlated with the factor Xa inhibition, but is associated with thrombin generation inhibition and potentiation of heparin cofactor II. Meanwhile, others factors, still non entirely identified, i.e. like the release of endogenous tissue plasminogen activators, must probably be involved in the antithrombotic activity of dermatan sulphate. In contrast to heparin, dermatan sulphate possesses hemorrhagic properties only at doses which are forty times higher than the antithrombotic dose. These hemorrhagic properties seem associated with an inhibition of collagen induced platelet aggregation. Finally, the pharmacokinetic profile of dermatan sulphate after intravenous injection in the rabbit, is different from that of standard heparin, and close to that of low molecular weight heparins.

Animals↗
PubMed1988

Comparison of thrombolytic, fibrinolytic, and fibrinogenolytic properties of tissue plasminogen activator, streptokinase, single-chain urokinase, high molecular weight and low molecular weight urokinase in human plasma in vitro.

Thrombolytic, fibrinolytic, and fibrinogenolytic properties of tissue plasminogen activator (t-PA) from melanoma cells (mt-PA), recombinant t-PA (rt-PA), streptokinase (SK), single-chain urokinase plasminogen activator (scu-PA), and high and low molecular weight urokinase (HMW UK, LMW UK) were compared in vitro by means of systems using human plasma. Thrombolytic activities were tested on standard or labeled hanging clots. When compared on the basis of urokinase international units, t-PA appeared to be slightly more active than scu-PA and streptokinase, and about 10-fold more active than both preparations of UK when they were diluted in plasma. Fibrinolytic activity was evaluated by measuring the lysis time of recalcified plasma containing variable amounts of thrombolytic agents. t-PA was shown to be twice as active as HMW UK, which was itself more active than LMW UK. When scu-PA and both types of UK were compared on bovine fibrin plates, they showed similar fibrinolytic activity, but the t-PA calibration curve was not parallel to those obtained with UK and scu-PA. Relative thrombolytic and fibrinogenolytic properties were studied for each thrombolytic agent. For similar thrombolytic activities, fibrinogenolysis provoked by scu-PA was less marked than with t-PA and with both UK, while SK showed the highest activity. Our results demonstrate that the thrombolytic/fibrinogenolytic ratio is much more favorable to t-PA and scu-PA than to both forms of UK. Another observation clearly shows that fibrinogenolysis can be induced in vitro in human plasma by high doses of t-PA. This consequence may be important since the therapeutic use of t-PA can be associated with high concentrations of t-PA, and thus t-PA infusion could lead in vivo to severe fibrinogen breakdown. In addition, the methodology described could be useful in standardizing comparison between different species of thrombolytic agents.

Fibrinogen↗
PubMed1986

[Surgical excision of meningioma of the posterior fossa in a dog after detection by x-ray computed tomography].

Following the progressive occurrence of a central vestibular syndrome in a 9 year old female dog, the diagnosis of a compressive lesion was confirmed by cerebrospinal fluid analysis (C.S.F.) and by computerized axial tomography (C.T.). The C.T.Scan revealed a large tumor occupying two thirds of the posterior fossa on the right side. A direct surgical approach to the right side of the posterior fossa revealed a large, friable mass, consistent with a meningioma, underneath the cerebellum, over the brain stem. Microscopic surgical dissection permitted the removal of the major part of the tumor. The nature of the intracranial neoplasm was confirmed histopathologically as a meningioma. No post operative complication arose and the dog returned to normal. Three months later, clinical signs reappeared and a control C.T.Scan showed recurrence of the tumor. The dog was euthanized four months postsurgically. Intracranial tumors are common in the dog, but rarely diagnosed and operated. However, a direct surgical approach to the posterior fossa for a tentative curative removal of an intracranial tumor has never been described in a dog. The localization and description of the lesions demonstrate the utility of C.T.Scans in the canine species. Recurrence of the tumor following surgery confirms the importance of complete excision of intracranial meningiomas when possible.

Animals↗
PubMed1978

Kinetics of plasma coagulation and lysis I: Basic kinetic model for time course of coagulation-lysis systems and its potential application to clinical studies.

The time courses of coagulation and coagulation-lysis were spectrophotometrically monitored after the addition of thrombin or thrombin-streptokinase to plasma, diluted 1:5 with normal saline, obtained from normal and presumably abnormal subjects. The kinetics of clotting, after an initial lag period of 0.5-1.5 min, demonstrated essentially first-order dependence on the amount of fibrinogen available to form the clot, and the asymptotic absorbance was independent of thrombin concentration. The rate of clotting was a function of added thrombin, and the ratios of the rate constants at 2.5 and 1.25 units of thrombin/ml of undiluted plasma were 1.65 +/- 0.03 SEM. At early times, the coagulation-lysis curve with thrombin-streptokinase could be superimposed on the clotting curve with thrombin alone for a given plasma with minor compensation for variable lag times. Subsequently, the curves diverged; lysis was monitored by the decrease in absorbance of the coagulation-lysis system. The rate of fibrinolysis increased with streptokinase concentration and was a function of the extent of lysis, and it permitted the description of the kinetics of lysis by a pseudoautocatalytic mechanism where the bimolecular rate constant appears proportional to streptokinase concentration. Ranges of clotting and lytic parameters for the plasma of normal subjects are given, and their potential use in diagnosing abnormalities is described.

Blood Coagulation↗
PubMed1976

Ultrastructural immunocytochemical localization of luteinizing hormone-releasing hormone (LH-RH) in the median eminence of the guinea pig.

LH-RH was localized at the ultrastructural level in axons and nerve terminals of the median eminence of the male guinea pig. LH-RH positive neuronal profiles were most concentrated in the medial-dorsal aspect of the infundibular stalk and in the post-infundibular median eminence at the level immediately following separation of the stalk from the base of the brain. LH-RH containing axon profiles were most abundant in the palisade zone; nerve terminals in contact with the hypophysial portal vasculature were relatively rare. The hormone was present within granules that measured 900-1,200 A in axons of the palisade zone and 400-800 A in nerve terminals abutting on the portal plexus. The differently sized granules represent heterogeneous populations.

Animals↗
PubMed1975

Post-natal development of the median eminence of the guinea pig.

The ultrastructure of the median eminence of neonatal (newborn) 1-, 3-, 5-, and 10-day old) and adult guinea pigs was studied to determine the dynamic changes occurring in this structure during early life. At birth the portal vasculature consists of the Mantelplexus and a few, non-fenestrated capillary loops. The number of ansae and the degree of fenestration increase rapidly after birth. The abundance of cytoplasmic and ciliary projections into the ventricular recess and the large numbers of organelles indicate that the ependymal cells are more active in the neonatal period than in the adult male. Moreover, the ependymal endfeet cover most of the surface area of the primary portal plexus during this time. The neuronal layers of the median eminence are difficult to distinguish at birth due to the lack of myelinated fibers in the zona interna. Significant myelination appears on day 3 but is not complete until day 10. There is a progressive increase in the numbers of Herring bodies and large neuro-secretory granules (1,500-1,700 A) during this same time period. In the zona externa, few nerve terminals abut on the perivascular space until day 3. Increases in numbers of granules per axon profile were noted for each day after birth. Despite the relatively long gestation period of the guinea pig (68-72 days), the morphologic appearance of the median eminence at birth suggests that the neurovascular link controlling anterior pituitary function is not yet complete.

Animals↗