Cerebral tissue oxygen saturation values in volunteers and patients in the lateral decubitus and beach chair positions: a prospective observational study.

Background: The objective of this study was to describe changes in cerebral tissue oxygen saturation (SctO2) due to changes in body position in healthy volunteers and in patients undergoing surgery under general anesthesia in the beach chair position (BCP) and lateral decubitus position (LDP).

Methods: In this prospective observational study, SctO2 was measured in 85 awake volunteers serially positioned every 15 min, beginning with the supine position (SP) and followed by the beach chair, supine, and lateral decubitus positions. Cerebral tissue oxygen saturation was also measured supine and in either the BCP or the LDP in 195 patients (according to surgical preference) undergoing elective arthroscopic shoulder surgery.

Preconditioning of the distal tubular epithelium of the human kidney precedes nephrocalcinosis.

Background: Preterm neonates and renal transplant patients frequently develop nephrocalcinosis. Experimental studies revealed that crystal retention in the distal nephron, a process that may lead to nephrocalcinosis, is limited to proliferating/regenerating tubular cells expressing hyaluronan and osteopontin at their luminal surface. Fetal and transplant kidneys contain proliferating and/or regenerating cells since nephrogenesis is not completed until 36 weeks of gestation, while ischemia and nephrotoxic immunosuppressants may lead to injury and repair in renal transplants.