Biomedical subjects

John R Hess

Publications and source records attributed to John R Hess.

22 records · Page 2Linked to original sources

PubMed2003

Twelve-week RBC storage.

BACKGROUND: Better storage can improve RBC availability and safety. Optimizing RBC ATP production and minimizing hemolysis has allowed progressively longer storage. STUDY DESIGN AND METHODS: In the first study, 24 units of packed CPD RBCs were pooled in groups of four, realiquoted, and added to 300 mL of one of four variants of experimental additive solution 76 (EAS-76) containing 45, 40, 35, or 30 mEq per L NaCl. Units were sampled weekly for 12 weeks for morphologic and biochemical measures. In the second study, 10 volunteers donated 2 units of RBCs for a crossover comparison of Tc/Cr 24-hour in vivo recovery of 6-week storage in AS-1 versus 12-week storage in EAS-76 variant 6 (EAS-76v6) having 30 mEq per L NaCl. RESULTS: RBCs stored in the lower salt variants of EAS-76 had higher concentrations of RBC ATP with less hemolysis and microvesiculation. RBC 2,3 DPG was preserved for two weeks. RBCs stored for 12 weeks in EAS-76v6 exhibited 78 +/- 4 percent 24-hour in vivo recovery. CONCLUSIONS: It is possible to store RBCs for 12 weeks with acceptable recovery and 0.6 percent hemolysis and with normal 2,3 DPG concentrations for 2 weeks.

2,3-Diphosphoglycerate↗

PubMed2003

Advanced hemostatic dressing development program: animal model selection criteria and results of a study of nine hemostatic dressings in a model of severe large venous hemorrhage and hepatic injury in Swine.

BACKGROUND: An advanced hemostatic dressing is needed to augment current methods for the control of life-threatening hemorrhage. A systematic approach to the study of dressings is described. We studied the effects of nine hemostatic dressings on blood loss using a model of severe venous hemorrhage and hepatic injury in swine. METHODS: Swine were treated using one of nine hemostatic dressings. Dressings used the following primary active ingredients: microfibrillar collagen, oxidized cellulose, thrombin, fibrinogen, propyl gallate, aluminum sulfate, and fully acetylated poly-N-acetyl glucosamine. Standardized liver injuries were induced, dressings were applied, and resuscitation was initiated. Blood loss, hemostasis, and 60-minute survival were quantified. RESULTS: The American Red Cross hemostatic dressing (fibrinogen and thrombin) reduced (p < 0.01) posttreatment blood loss (366 mL; 95% confidence interval, 175-762 mL) and increased (p < 0.05) the percentage of animals in which hemostasis was attained (73%), compared with gauze controls (2,973 mL; 95% confidence interval, 1,414-6,102 mL and 0%, respectively). No other dressing was effective. The number of vessels lacerated was positively related to pretreatment blood loss and negatively related to hemostasis. CONCLUSION: The hemorrhage model allowed differentiation among topical hemostatic agents for severe hemorrhage. The American Red Cross hemostatic dressing was effective and warrants further development.

Animals↗

PubMed2002

Alkaline CPD and the preservation of RBC 2,3-DPG.

BACKGROUND: Concentrations of 2,3-DPG decline rapidly in the first week of RBC storage because of the low pH of conventional storage solutions. Alkaline additive solutions, which can preserve RBCs for up to 11 weeks, still do not preserve 2,3-DPG because the starting pH is below 7.2. STUDY DESIGN AND METHODS: Alkaline CPD (pH=8.7) was made with trisodium citrate, dextrose, and disodium phosphate. Twelve units of whole blood were collected into heparin and pooled in groups of four units. Each pool was then aliquoted into four units; 63 mL of CPD with pH 5.7, 6.5, 7.5, or 8.7 was added to one unit of each pool, and 300 mL of the alkaline experimental additive solution-76 was added. In Study 2, 12 units were collected into alkaline CPD, pooled in groups of four, aliquoted as described, and stored in four variants of experimental additive solution-76 containing 0, 9, 18, and 27 mM of disodium phosphate. RBC ATP and 2,3-DPG concentrations, intracellular and extracellular pH and phosphate concentrations, hemolysis, and other measures of RBC metabolism and function were measured weekly. RESULTS: RBCs stored in more alkaline conditions made 2,3-DPG, but at the expense of ATP. Concentrations of 2,3-DPG decreased after 2 weeks storage, but ATP concentrations never fully recovered. Providing more phosphate both increased the duration of 2,3-DPG persistence and raised ATP concentrations in the later stages of storage. CONCLUSIONS: Maintaining both 2,3-DPG and ATP requires both high pH and high concentrations of phosphate.

2,3-Diphosphoglycerate↗

PubMed2002

Storage of red blood cells: new approaches.

Longer red blood cell (RBC) storage can improve blood logistics, increase the usefulness of autologous blood storage, and reduce donor exposure in neonatal intensive care. Better RBC storage can prevent membrane loss and preserve the secretion of adenosine 5'-triphosphate (ATP) in response to deformation. Better RBC storage may also reduce the formation of proinflammatory membrane breakdown products that lead to transfusion-related acute lung injury and the systemic inflammatory response syndrome. To improve RBC storage, the authors have attempted to maximize the production of ATP by the manipulation of pH and to minimize membrane loss through the use of membrane protectants and the manipulation of tonicity. Increasing the initial storage pH led to successively higher RBC ATP concentrations until pH 7.2 was reached, when the synthesis of 2,3-diphophoglycerate was initiated at the expense of ATP. Synthesis of ATP could be maintained by buffering the fall of pH with increased storage solution volume or the addition of bicarbonate. Maintaining RBC ATP turns out to be an important way of preventing membrane microvesiculation or blebbing, as does the manipulation of tonicity and the addition of mannitol. These experiments show that it is possible to store RBC in experimental additive solutions containing only saline, adenine, glucose, mannitol, sodium bicarbonate, and disodium phosphate for 11 weeks or longer with little loss of membrane and high in vivo recovery.

2,3-Diphosphoglycerate↗