Evaluation of the haemocompatibility of titanium based biomaterials.

The increased use of metallic biomaterials in contact with blood e.g. for the application as coronary stents leads to the development of new biomaterials. The main requirements for stents are high flexibility, high cold deformability and sufficient mechanical strength (static and dynamic), which can be obtained by strain hardening, radio-opacity and haemocompatibility. In order to investigate the properties of the metallic biomaterials in contact with blood, a comparison of the haemocompatibility of newly developed materials with established materials has been performed. To evaluate haemocompatibility without the influence of the geometry of the material, spherical powders produced by rotating electrode process (REP) were used in a dynamic test system with full human blood under two different stress conditions. The high shear stress simulates the arterial and the low shear stress simulates the venous situation. The use of a dimensionless score point (SP) system where the parameters of the haemocompatibility are determined with and without a material exposition allows an objective comparison of the materials used.

Pregnancy outcome after artificial insemination or IVF with frozen semen donor: a collaborative study of the French CECOS Federation on 21,597 pregnancies.

OBJECTIVE: To assess pregnancies and conceptus after artificial insemination (AID) or IVF with frozen semen donor (IVF-D) on sufficiently large study population in order to distinguished minor variations. STUDY DESIGN: From 1987 to 1994, all pregnancies obtained after AID or IVF-D were registered prospectively in the French CECOS Federation data base. Different factors were recorded for this study: first menarche age of the recipient women, cycle length, insemination date in the conception cycle, maternal age at delivery, hormonal treatments, donor age, sperm conservation length and follow up of the pregnancy: miscarriage, tubal pregnancy, time at delivery, sex of the foetus, weight, malformation. RESULTS: 21,597 pregnancies obtained after AID and 3381 after IVF-D were registered. 2% were lost to follow up. Foetal loss rate is 18% after AID and 21.5% after IVF-D (p < 0.001). The tubal pregnancy rate is 0.9% after AID and 1.7% after IVF-D (p < 0.0001). 18,128 children were born after AID and 3313 after IVF-D. After AID, the twin pregnancy rate is 6.9% and the multiple pregnancy (> or = 3 foetus) rate is 0.7%. After IVF-D, these rates are 24.8% and 4.2% respectively (p < 0.0001). After AID the mean weight at delivery, sex ratio, premature rate, intra uterine growth retardation rate are not different from national rates published in 1995. The foetus malformation rate (including medical abortions) is 1.9% after AID and 2.7% after IVF-D (p < 0.009). After AID the trisomy 21 rate increases with the mother age but also with the donors age if the maternal age is equal. The birth defects rate is not different from those registered in Paris, Strasbourg and Marseille. The birth defects rate observed after IVF-D is not different from the rate observed after IVF with husband semen. (2.74% versus 2.99%; p = 0.16). CONCLUSION: After AID the miscarriage and tubal pregnancy rate, the children's weight, the premature rate is not different from that of the general French population. Sex ratio is normal as is the global malformation rate. The multiple pregnancy rate (x 7 for twin and by 10 for multiple pregnancies more than 3 foetus) is high, showing the influence of ovulation induction treatment. The birth chromosomal abnormalities rate is normal and correlated not only to the mother's age but also to the donor's age. This result without clear biological explanation will require further verification in a greater population. Practically speaking, these observations encourages lowering the age limit for semen donors less than 45 years. IVF-D practice instead of AID doubles the tubal pregnancy rate (0.9% versus 1.7% and increases the twin pregnancy rate by 2.5% and the multiple pregnancy (> or = 3 fetus) rate by 3. It is necessary to promote good practice for AID for which the pregnancy rate is very different from one centre to another within the centres with AID low results a too high rate of IVF-D. Finally we can say that pregnancies from IVF-D or IVF with husband semen are not significantly different. In other words pregnancy outcome is not changed after sperm cryopreservation.

Incidence of birth defects after artificial insemination with frozen donor spermatozoa: a collaborative study of the French CECOS Federation on 11,535 pregnancies.

Artificial insemination using cryogenically preserved spermatozoa has been widely used in human reproduction for several decades. No evaluation of the resulting pregnancies and conceptions has been undertaken in sufficiently large study populations for minor variations to be distinguished. This study involves 11,535 pregnancies conceived by artificial insemination using donor spermatozoa and followed from the time that pregnancy was diagnosed. The pregnancies followed a normal course with, in particular, no excessive fetal losses. While the global incidence of birth defects was similar to that of natural conception, our observations raise doubts concerning trisomy 21. The frequency of trisomy 12 was somewhat elevated when compared with French malformation registries. A recruitment bias could, in part, explain this discrepancy, but donor age cannot be excluded as an influencing factor.

[Paternal age and pregnancy issues. The CECOS experience]. / Age paternel et issues de grossesses. Expérience des CECOS.

From a collaborative study of the French "Federation des CECOS" who collected the follow up of 11,535 pregnancies, the effect of parental age on the offspring is studied. A significant influence of the donor's age is demonstrated for the occurrence of trisomy 21 (37.4 +/- 7.8 vs 34.5 +/- 6.0; p < 0.05).