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Biomedical subjects

P Girardin

Publications and source records attributed to P Girardin.

13 recordsLinked to original sources
PubMed1990

Rabbits infested with Ixodes ricinus L. adults: effects of a treatment with cyclosporin A on the biology of ticks fed on naive and immune hosts.

Rabbits have been infested 3 times with 10 female and 10 male Ixodes ricinus. Immunity which is induced when ticks feed on naive animals (1st infestation) perturbs feeding, oviposition and embryogenesis during reinfestations. Treatment of rabbits during a 3rd infestation (resistant animals) with cyclosporin A (CsA), an immunosuppressive agent which works on the cellular compartment (chiefly T helper cells), partially reversed the negative effects of the immunity on the biology of the ticks. Conversely, CsA may also directly affect the reproductive processes of ticks. Thus, the weight of the eggs laid and the egg conversion factor of ticks fed on naive treated hosts (1st infestation) were diminished. In addition, the preoviposition was prolonged, and finally failure in oviposition and hatching occurred more frequently.

Animals↗
PubMed1989

Effects of cyclosporin A on humoral immunity to ticks and on cutaneous immediate and delayed hypersensitivity reactions to Ixodes ricinus L. salivary-gland antigens in re-infested rabbits.

When rabbits are repeatedly infested with Ixodes ricinus L. adults, they acquire resistance to these ticks. A humoral response occurs and the skin of the host becomes progressively sensitized to the saliva of the ectoparasites. The present study examined the effects of cyclosporin A on these two aspects of immunity in re-infested rabbits. Using the enzyme-linked immunosorbent assay (ELISA), moderate suppression of the secondary IgG response to bites of these ticks was observed in animals given this immunosuppressive drug. The agent blocked the immediate cutaneous (type I) reaction normally developed in response to the intradermal injection of I. ricinus salivary gland antigens, as detected by measuring the skinfold thickness. The same method revealed a decreased delayed (type IV) hypersensitivity to these antigens. The present experiments demonstrate the major role of cyclosporin A-sensitive cells (mostly T-lymphocytes, mast cells and basophils) involved in the complex phenomenon of resistance to ticks.

Animals↗
PubMed1986

[Stabilization of the external condyle of the knee in chronic anterior laxity. Importance of the popliteal muscle].

The authors have made an anatomical and experimental study in cadavers. They consider that one of the main features of chronic anterior instability of the knee is related to the instability of the lateral femoral condyle. This is due to the loss of its two stabilizers: the anterior cruciate ligament and the popliteal muscle. The signs of a lesion of the postero-lateral structures have to be looked for: antero-posterior drawer sign in extension, hypermobility of the tibia in lateral rotation and varus laxity. Such instability leads to arthrosis in the long-term. The proposed treatment is based on a reconstruction of the anterior cruciate ligament, using semitendinosus associated with a postero-lateral reconstruction using either the biceps or the fascia lata, or a free transplant from the patellar ligament. Corrective osteotomy of an associated varus deformity may be indicated.

Biomechanical Phenomena↗
PubMed1985

[Epidemiologic characteristics of 21 peranesthetic anaphylactoid accidents observed in a population of 12,855 surgically treated patients].

A study of anaphylactoid reactions (AR) observed between September 1982 and September 1983 was carried out in the surgical departments of a French regional hospital. The patients who had presented clinical symptoms suggesting an AR (bronchospasm, collapse, tachycardia, with or without skin rash) during a general anaesthesia were included in this study. A precise history of previous anaesthesias and allergy was taken; allergological testing was carried out six to eight weeks after the AR. It included intradermal skin tests (ST) and a human basophil degranulation test (HBDT) with the suspected drugs. Out of 12,855 patients operated on under general anaesthesia in the hospital, 21 AR were seen during the year under study, in 18 women and 3 men, of median age 27 years (extreme values: 11 and 62). The median number of previous anaesthesias was 2 (extreme values: 0--in 4 cases- and 22). Cardiocirculatory abnormalities were the most frequent clinical symptoms of the AR: they consisted of decreased arterial pressure in 13 cases, with 8 cases of vascular collapse. Respiratory symptoms were less frequent but severe bronchospasm was observed in 5 cases. Skin rashes were seen simultaneously in 13 out of the 21 observations. A history of allergy was found in 11 patients. Total IgE serum concentration averaged 134 kU X 1(-1) (extreme values: 32-378). Results of histamine-sensitivity skin tests were not significantly different from those observed in a control group. Calcemia and magnesemia were in the normal range. One to four drugs were tested in each patient: 41 tests combining ST and HBDT were carried out.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1979

Passive transfer of resistance in rabbits infested with adult Ixodes ricinus L: humoral factors influence feeding and egg laying.

Parital immunity against the bites of female I. ricinus was transferred to normal rabbits by inoculating immune serum from resistant animals. Transferred humoral factors diminished the weight of the ticks' blood meal by 29% and increased the feeding period by about 1 day in comparison with ectoparasites engorged on controls. They provoked also the failure of egg laying by female I. ricinus. Only 55% of ticks fed on treated rabbits laid eggs (94% on controls). The immunological state of immune serum donors or recipients was studied and the IgG and homocytotropic specific anti-I. ricinus antibodies were identified. The immediate hypersensitivity of rabbits' skin was also controlled.

Animals↗