Left upper quadrant laparoscopic placement: effects of insertion angle and body mass index on distance to posterior peritoneum by magnetic resonance imaging.

OBJECTIVE: To determine the ideal angle for insertion of laparoscopic instruments at Palmer's point. STUDY DESIGN: Abdominal magnetic resonance images were reviewed for 75 women between ages 18 and 50 years old. The distance from the skin to the retroperitoneal structures were determined perpendicular to the spine and angled 45 degrees caudally. RESULTS: When instruments are inserted perpendicular to the skin in the axial plane and peritoneum perpendicular to the spine, the distance from skin to posterior was 10.0 +/- 0.2 cm and to the aorta was 11.3 +/- 0.2 cm. If instruments are inserted at an angle 45 degrees caudally, this distance increased to 16.6 +/- 0.2 cm. CONCLUSION: When inserting laparoscopic instruments at Palmer's point, insertion perpendicular to the skin in the axial plane and angled 45 degrees caudally in relation to the spine offers an increased margin of safety compared with insertion perpendicular to the spine, particularly in thin women.

Reproductive corticotropin releasing hormone, implantation, and fetal immunotolerance.

The fundamental process of implantation involves a series of steps leading to effective cross-talk between invasive trophoblast cells and the maternal endometrium. The molecular interactions at the embryo-maternal interface during the time of blastocyst adhesion and subsequent invasion are not fully understood. Embryonic trophoblast and maternal decidual cells produce corticotropin-releasing hormone (CRH) and express Fas ligand (FasL), a proapoptotic cytokine. Fas and its ligand are pivotal in the regulation of immune tolerance. Trophoblast and decidual CRH play crucial roles in implantation, as well as in the anti-rejection process that protects the fetus from the maternal immune system, primarily by killing activated T cells through Fas-FasL interaction. The potential use of CRH antagonists is presently under intense investigation. CRH antagonists have been used experimentally to elucidate the role of CRH in blastocyst implantation and invasion, early fetal immunotolerance, and premature labor.