General anesthesia for surgery influences melatonin and cortisol levels.

The purpose of this study was to investigate the effect of general anesthesia and surgery on melatonin production, and to assess the relationship between melatonin secretion and cortisol levels. Twenty (9 males and 11 females) consecutive otherwise healthy patients aged 27 to 52 years were included in this study. The patients underwent laparoscopic cholecystectomy or laparoscopic hernioplasty. All patients had general anesthesia with the same anesthetic drugs. Serum cortisol levels were measured at several time periods. Urine collections for melatonin were performed from 18:00 to 7:00 the day prior to surgery, on the operation day, and on the first postoperative day. Baseline melatonin metabolites were measured the night prior to surgery, and the level was found to be 1979 +/- 1.76 ng. The value decreased to 1802 +/- 1.82 ng (NS) on the night of surgery, and it became a significantly higher, reaching 2981 +/- 1.55 ng the night after surgery (p = .003). The baseline daytime cortisol level was significantly lower than the baseline night cortisol level (6.87 +/- 1.51 microg/dl, 14.89 +/- 1.66 micrograms/dl, respectively, p < 0.0001). Surgery induced a significant increase in both day and night cortisol levels. Daytime cortisol levels increased from 6.89 +/- 1.51 microg/dl to 16.90 +/- 1.27microg/dl (p < 0.0001), whereas right levels increased from 14.89 +/- 1.66 microg/dl to 29.20 +/- 1.24 microg/ dl (p <0.0001). The morning after surgery, cortisol levels decreased to 10.16 +/- 1.40 microg/dl, lower than the value obtained on the day of surgery (p < 0.0001). As was true of melatonin, cortisol levels did not reach the pre operative level (p < 0.005). The finding of the current study is that melatonin and cortisol levels show an inverse correlation after surgery.

Whole blood platelet deposition on extracellular matrix under flow conditions in preterm neonatal sepsis.

UNLABELLED: Platelet function in preterm infants with sepsis was evaluated by measuring their adhesion and aggregation properties using the Cone and Plate(let) Analyser. This may lead to earlier detection of bleeding tendency in septic infants. Platelet function was investigated in 54 preterm infants, of whom 32 had proven neonatal sepsis and 22 were healthy matched controls. Citrated whole blood was subjected to shear stress (1300 s(-1)) for 2 min on tissue culture plates precoated with subendothelial extracellular matrix (ECM). The percentage of ECM surface covered with platelets and the average size of the ECM-bound platelet particles were determined with an image analyser. Assays for von Willebrand factor (vWF) antigen, ristocetin co-factor, and vWF collagen binding activity (CBA) were performed on samples from an additional 47 preterm infants: 38 healthy and 9 septic. Platelets of the preterm infants with sepsis displayed lower adhesion than those of the healthy controls. Mean surface coverage was 16.9+/-8.2% for the septic infants, 15.4+/-7.9% for the septic infants after exclusion of those with coagulase-negative staphylococci sepsis, and 20.8+/-9.6% for the healthy group ( P<0.05). Platelet aggregation, vWF antigen, ristocetin co-factor, and CBA levels were similar between the septic and healthy groups. The most significant factor influencing surface coverage was the presence of sepsis. CONCLUSION: platelet adhesion to extracellular matrix is significantly lower in septic preterm infants than in healthy preterm infants. Intrinsic platelet properties, rather than the concentration or activity of plasma von Willebrand factor, may be responsible for this difference. Surface coverage obtained by the collagen binding activity test under flow conditions, which represents platelet adhesion, may be an earlier, more sensitive indicator of bleeding tendency in neonatal sepsis than decreased platelet count.