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Biomedical subjects

P Picard

Publications and source records attributed to P Picard.

At least 55 records · Page 3Linked to original sources
PubMed1992

[Drug treatment of perioperative pain].

Several drugs and techniques have been developed to improve the quality of post operative analgesia. Opiates are always the first intention drugs, specially with new molecules (buprenorphine, nalbuphine ...). Paracetamol and non-steroid anti-inflammatory drugs can be efficacious in the post operative period alone or as adjuvants. The alpha 2 adrenergic agonists use must be specify. The patient auto-controlled administration and the transdermal administration of opiates are useful techniques to provide effective analgesia with optimal safety.

Administration, Cutaneous↗
PubMed1991

The dimension of Reed-Frost epidemic models with randomized susceptibility levels.

A generalized Reed-Frost epidemic process is discussed in which variability among susceptible individuals is incorporated by randomizing the levels of resistance of the individuals to the infection. Our purpose is to derive the exact distribution of the ultimate number of susceptibles surviving the disease. This is achieved by a simple conditional argument and by using a particular family of polynomials defined recursively. The results can be viewed as a continuation of those obtained by the authors for the alternative situation with randomized infectivity levels.

Disease Outbreaks↗
PubMed1989

On the formulation of discrete-time epidemic models.

Jacquez constructed a properly posed, more general model for the Reed-Frost epidemic process by assuming independent behaviors for the susceptibles and introducing the generating function for the number of contacts per person. An alternative approach is proposed here that relies on similar hypotheses for the infectives and allows the usual chain-binomial structure of the infection process to be extended. For this new model, the derivation of the final size and the threshold phenomenon becomes much simpler. A detailed analysis and its generalization to heterogeneous populations and continuous-time models will be the subject of a forthcoming paper.

Disease Outbreaks↗
PubMed1989

Two variants of the first Nåsell-Hirsch model.

Two models are propounded on the general setting of the first Nåsell-Hirsch model for helminthic infections. They differ from it in the two processes of transmission of the infection, which are treated dissymmetrically. In each model only one of these processes will be deterministic, instead of both as in the Nåsell-Hirsch case, the other process being kept fully stochastic. These new models lead to results that show a general agreement with those of Nåsell and Hirsch but also some interesting differences.

Animals↗
PubMed1989

Hidden reproductive costs in the three-spined stickleback (Gasterosteus aculeatus).

The costs of parental behaviour (fanning) were examined in male 1+ and 2+ three-spined sticklebacks (Gasterosteus aculeatus) by comparing the loss of wet mass incurred by starved parental males during the egg care period to those incurred by starved non-parental males during this same period. To evaluate which tissues were most affected, we compared the wet and dry masses of the tissues in our starved fish with those of an additional group of fed non-parental fish. While parental and non-parentals did not differ in their absolute loss of wet mass (two age classes combined), parentals had a significantly lower total dry mass than both fed and starved non-parentals (two age classes combined). These data suggest that the parental behaviour of males imposes an energetic cost which these males hide by increasing their water content. The difference in dry mass of the tissues of parental and non-parental males was most pronounced in the tissues remaining after removal of the muscles from the carcass, i.e. the skin, the vertebral column and the head. While age 1+ fish lose significantly less wet mass over the breeding cycle than age 2+ fish, this loss of mass represented a greater proportion of the body mass of 1+ than of 2+ fish. This may explain why fewer age 1+ fish than age 2+ successfully breed at our field site.

Animals↗
PubMed1988

Characterization of an antibody directed against a 128 kDa glycoprotein involved in the thrombogenicity of the elastin-associated microfibrils.

We have developed a monospecific antiserum directed against a major glycoprotein in the elastin-associated microfibrils with an apparent molecular mass of 128 kDa (GP 128). When immunoblotting or enzyme-linked immunosorbent microassay was used, its IgGs recognized thrombospondin in a platelet lysate, but did not react with several basement-membrane-derived macromolecules, nor with plasma fibronectin. Similar patterns of immunofluorescence and immunoperoxidase were found after incubation of endothelial cells with either anti-GP 128 or anti-(platelet thrombospondin) IgGs. Both antibodies inhibited the microfibrils- and thrombin-induced platelet aggregation, and were without effect on the aggregation by other inducers. These results confirm that there is an antigenic homology between GP 128 and thrombospondin.

Blood Coagulation↗
PubMed1982

The human blood platelet: a cellular model to study the degradation of thymidine and its inhibition.

Intact platelets catabolize extracellular thymidine into thymine. Studies of the concentration dependent degradation of thymidine by intact platelets indicate a Michaelis mechanism with an apparent Km of about 0.12 mM and a Vmax of 2.5 nmoles/min for 3 X 10(8) platelets. This degradation process is inhibited by various nucleosides, pyrimidine bases and C-5 or C-6 substituted uracils. Cytidine, deoxycytidine, adenosine and deoxyadenosine seem to inhibit thymidine degradation by reducing the intracellular transport of thymidine. Uridine inhibits both the thymidine transport and the activity of the phosphorolytic enzyme, thymidine phosphorylase (EC 2.4.2.4). Some substituted uracils are specific inhibitors of thymidine phosphorylase activity. 6-Amino-5-bromouracil, the most active of them, either with acellular extracts or purified thymidine phosphorylase, is also the best inhibitor of thymidine degradation in intact human platelets. Platelets constitute a new model to study the efficiency of specific inhibitors on thymidine catabolism in an 'human intact cell' which contains only one pyrimidine nucleoside phosphorylase, the thymidine phosphorylase.

Biotransformation↗
PubMed1979

[Partial fractures of the patella (author's transl)].

The authors reviewed the blood supply of the patella necrosis and pseudarthrosis were retained after patella fracture. These complications made the authors better defining the vascular anatomy of the patella region. A poor peripheral blood supply and a special vascular pedicle to the tip are suggested as an factor of these complications.

Adolescent↗