Uptake and transport by the ovine placenta of neutral nonmetabolizable amino acids with different transport system affinities

In 32 published reports in surgical patients, the preponderance of evidence from standard clinical measures of renal function (BUN and Cr) indicates the absence of renal toxicity following sevoflurane anesthesia. Studies of surgical patients receiving intermediate-duration sevoflurane with high or low fresh gas flow and long-duration sevoflurane with high fresh gas flow included sensitive measures of renal function and/or injury, which also indicate the absence of renal toxicity following sevoflurane anesthesia. Studies of surgical patients receiving long-duration sevoflurane with low fresh gas flow did not include sensitive measures. Seven studies in volunteers are not directly relevant to clinical practice but do raise the issue of whether it is important to apply sensitive measures of renal function and/or injury such as urine concentrations and/or excretion of NAG, beta 2M, alpha 1M, AAP, alpha GST, pi GST, gamma GTP, albumin, protein, and glucose and Cr clearance. Two studies of volunteers receiving prolonged sevoflurane anesthesia with fresh gas flow no greater than 2 L/min concluded that the potential for adverse renal effects of sevoflurane may exist. The other studies of volunteers did not. In 14 published reports of surgical patients in special conditions, the preponderance of evidence from standard clinical measures of renal function indicates the absence of renal toxicity. Studies with sensitive measures have been reported for some conditions where the kidney may be at increased risk (e.g., sevoflurane-induced hypotension, advanced age, and renal insufficiency and failure), are incomplete in others (e.g., hypertension and ischemic heart disease), and are missing in others (e.g., morbid obesity). Studies with sensitive measures of renal function and/or injury are also missing in an important group where the kidney may not be at increased risk--pediatric patients. Studies of other risk conditions, such as temporary ischemia, hemorrhagic hypotension, nephrotoxic antibiotics, kidney transplantation, and diabetes may provide additional information about the renal effects of sevoflurane.     

Development of a Model System to Mimic Beef Bone Discoloration

ABSTRACT: Some current practices used in the meat industry (blast chilling, enhancement, modified atmosphere packaging [MAP]) appear to result in darkening of the bone in fresh meat. The objective of this study was to develop a model system that could be used to evaluate intervention strategies to prevent this discoloration. Beef rib bones were removed from carcasses, split along the transverse plane from the proximal to the distal end of the rib, and then frozen (−20 °C) or held at 4 °C for 24 h. Half were exposed to a phosphate/salt enhancement solution while half served as the control. Samples were packaged in air or modified atmosphere packaged (MAP: 80% O₂/20% CO₂) and displayed in a retail case (4 °C, 24 h). Visual discoloration occurred during the 1st 10 h of display. More darkening (brown, green/black) was observed in previously frozen samples, whereas samples held at refrigeration temperature were redder. CIE L *, a *, and b * values determined after 24 h indicated that samples held in refrigeration before packaging were lighter and redder. After 24 h at 4 °C, previously frozen samples contained more methemoglobin/g protein in the bone marrow than did bone samples that had never been frozen.