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Biomedical subjects

J Bonan

Publications and source records attributed to J Bonan.

6 recordsLinked to original sources
PubMed1996

[Acardiac fetus].

Acardiac fetus is a rare lethal fetopathy usually encountered in monozygous pregnancies. Ultrasound prenatal diagnosis has enabled an increasing number of observations and raised the need for an adequate therapeutic approach since the spontaneous prognosis for the healthy twin is unfavorable in half of the cases. An acardiac fetus was identified at 12 weeks gestation in a 36-year-old woman. Growth of the healthy fetus was carefully monitored and progressed normally to delivery by cesarean section of a 2.900 kg boy at 36 weeks. At delivery, the acardiac fetus was found to be totally free of any attachment, floating in the remaining fluids. Pathology examination showed a 16 g macerated fetus with a cephalic extremity, a ventral pedicle and a syrenomelic caudal extremity. The caryotype was not significative. Acardiac fetus occurs in less than 1% of multiple pregnancies and can develop in single pregnancies. Twin reversed arterial perfusion has been recognized as necessary for development of the perfused fetus. Genetic and immunologic theories have been proposed to explain the pathogenesis which remains unknown. Clinical management depends on the spontaneous development of the acardiac fetus and the deleterious consequences for the healthy twin resulting from heart failure, anasarca or prematurity. Medical management with digoxin, or selective extraction by hysterotomy may improve prognosis but results have been variable. Echoguided umbilical cord ligation has also been proposed to improve maternal mortality. Therapeutic abstention is no longer indicated at prenatal diagnosis of an acardiac fetus and a healthy twin despite the risk of invasive treatment.

Adult↗
PubMed1991

Modulation of platelet surface adhesion receptors during cardiopulmonary bypass.

Alterations in platelet receptors critical to adhesion may play a role in the pathogenesis of the qualitative platelet defect associated with cardiopulmonary bypass. Using flow cytometry, we measured changes in the following platelet surface adhesive proteins: the von Willebrand factor receptor, glycoprotein Ib; the fibrinogen receptor, glycoprotein IIb/IIIa; the thrombospondin receptor, glycoprotein IV; the adhesive glycoprotein granule membrane protein 140, whose expression also reflects platelet activation and alpha-granule release; and, as a control, the nonreceptor protein HLA, A,B,C. Glycoprotein Ib decreased during cardiopulmonary bypass (P less than 0.05) and reached a nadir at 72% (P less than 0.05) of its baseline value at 2-4 h after bypass. This decrease correlated (r = 0.76) with the magnitude of platelet activation (alpha-granule release) in any given patient, but even platelets that were not activated demonstrated a decrease in glycoprotein Ib expression. Glycoprotein IIb/IIIa also decreased in both the activated (47% of baseline, P less than 0.01) and unactivated (63% of baseline, P less than 0.01) subsets of platelets at the end of cardiopulmonary bypass. Glycoprotein IV and HLA A,B,C did not decrease, but instead increased 2-4 h after cardiopulmonary bypass (P less than 0.05). We conclude that cardiopulmonary bypass produces selective decreases in surface glycoproteins Ib and IIb/IIIa as well as in platelet activation; that these two alterations are temporally but not necessarily mechanistically linked; and that these changes have the potential to adversely affect platelet function.

CD36 Antigens↗