Severe Lactic Acidosis in a Critically Ill Child: Think About Thiamine! A Case Report.

In this article, we presented a teenager, in maintenance chemotherapy for leukemia, who was admitted for digestive symptoms related to a parasitic infection and required nutritional support with parenteral nutrition. After 6 weeks, his condition worsened with refractory shock of presumed septic origin, necessitating extracorporeal membrane oxygenation. Despite hemodynamic stabilization, his lactic acidosis worsened until thiamine supplementation was started. Lactate normalized within 12 hours. Thiamine is an essential coenzyme in aerobic glycolysis, and deficiency leads to lactate accumulation through anaerobic glycolysis. Thiamine deficiency is uncommon in the pediatric population. However, it should be considered in patients at risk of nutritional deficiencies with lactic acidosis of unknown origin

High Temperature Metal Hydrides as Heat Storage Materials for Solar and Related Applications

For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 °C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described

Fibrolase: Trials and Tribulations

Fibrolase is the fibrinolytic enzyme isolated from Agkistrodon contortrix contortrix (southern copperhead snake) venom. The enzyme was purified by a three-step HPLC procedure and was shown to be homogeneous by standard criteria including reverse phase HPLC, molecular sieve chromatography and SDS-PAGE. The purified enzyme is a zinc metalloproteinase containing one mole of zinc. It is composed of 203 amino acids with a blocked amino-terminus due to cyclization of the terminal Gln residue. Fibrolase shares a significant degree of homology with enzymes of the reprolysin sub-family of metalloproteinases including an active site homology of close to 100%; it is rapidly inhibited by chelating agents such as EDTA, and by alpha2-macroglobulin (α2Μ). The enzyme is a direct-acting thrombolytic agent and does not rely on plasminogen for clot dissolution. Fibrolase rapidly cleaves the A(α)-chain of fibrinogen and the B(β)-chain at a slower rate; it has no activity on the γ-chain. The enzyme exhibits the same specificity with fibrin, cleaving the α-chain more rapidly than the β-chain. Fibrolase was shown to have very effective thrombolytic activity in a reoccluding carotid arterial thrombosis model in the canine. A recombinant version of the enzyme was made in yeast by Amgen, Inc. (Thousand Oaks, CA, USA) and called alfimeprase. Alfimeprase is identical to fibrolase except for a two amino acid truncation at the amino-terminus and the insertion of a new amino-terminal amino acid in the truncated protein; these changes lead to a more stable enzyme for prolonged storage. Alfimeprase was taken into clinical trials by Nuvelo, Inc. (San Carlos, CA), which licensed the enzyme from Amgen. Alfimeprase was successful in Phase I and II clinical trials for peripheral arterial occlusion (PAO) and central venous access device (CVAD) occlusion. However, in Phase III trials alfimeprase did not meet the expected end points in either PAO or CVAD occlusion and in a Phaase II stroke trial, and Nuvelo dropped further development in 2008

Platelets and thrombogenesis--Current concepts

Anticoagulants, although effective in the treatment of venous thrombotic disease, have not been generally helpful in preventing arterial thrombosis. The reason for this disparity may lie in the type of clot formed in each case. In veins a "red thrombus" is formed, consisting of erythrocytes, leukocytes, fibrin, and platelets randomly distributed, whereas in arteries a "white thrombus" consisting mainly of platelets and fibrin strands is the obstructing lesion1. The predominance of platelets in this "white" clot has focused attention on their importance in arterial occlusion and has suggested that therapeutic maneuvers directed at platelet function may be more useful than standard anticoagulant therapy. This review presents the recent advances in the study of platelet morphology and function, and concludes by discussing possible therapeutic avenues.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34128/1/0000412.pd