Cryoprecipitates as a source of fibrinogen in treatment of disseminated introvascular coagulation (DIC)

Cryoprecipitates, in addition to containing factor VIII, contain about one third of the fibrinogen in the plasma from which they were derived. This fibrinogen is functional, as established by successfully preparing two congenital hypofibrinogenemics for major surgery by infusing cryoprecipitates. Cryoprecipitates and platelet concentrates are also used for patients with low levels caused by disseminated intravascular coagulation (DIC). We feel that these patients benefit not only from the factor VIII in the cryoprecipitates, but from the fibrinogen, which adds its support to the fibrinogen in platelet infusions, plasma, and whole blood. Such support makes it possible to heparinize such patients more heavily than would be safe without such preparation. The authors report three patients with severe and life-endangering DIC who were heavily heparinized, and supported with cryoprecipitates, as well as other blood fractions. Response to this therapy was excellent.     

Two-dimensional analysis of the structure of human von Willebrand factor

Human von Willebrand factor (vWF) is synthesized as an extra large polymer; then, it is converted to lower molecular weight plasma multimers, originally composed of intact 225-kDa subunits, by a metalloproteinase. Proteolysis generates two fragments of 140-and 176-kDa, which originate from cleavage of peptide bond Tyr842-Met843 and which represent vWF residues 1-842 and 843-2050, respectively; a very small amount of 189-kDa fragment can also be found in normal plasma. We describe here a two-dimensional (2-D) method to analyze plasma vWF structure.     

Are frequent short gastro-oesophageal reflux episodes the cause of symptoms in patients with non-ulcer dyspepsia responding to treatment with ranitidine?

BACKGROUND: Patients with non-ulcer dyspepsia (NUD) responding to treatment with H2-receptor antagonists have no clinically useful characteristics. This trial compares the gastro-oesophageal reflux pattern as measured by 24-h oesophageal pH monitoring in patients responding to ranitidine with that of non-responders. METHODS: Thirty-one patients with NUD were randomized to 6 weeks' double-blind alternating treatment with 150 mg ranitidine twice daily or placebo and classified as responders or non-responders. RESULTS: Pathologic gastro-oesophageal reflux was seen in 3 of the 13 responders and 4 of the 18 no-responders (NS). The responders had frequent short reflux episodes (< 1 min in duration). When 4 patients with > or = 5 reflux episodes longer than 5 min were excluded, the number of short reflux episodes (median) in responders and non-responders was 32 and 14, respectively. The difference is statistically significant (p = 0.025). There were no other differences between the groups. CONCLUSIONS: In this study patients with NUD responding to ranitidine were characterized by frequent short reflux episodes in the absence of numerous long reflux episodes.     

Heart rate and workload variations in actual and simulated flight

The monitoring of heart rate in aviation research provides a global index of pilot workload. Heart rate variability is a promising measure but more complex to assess and therefore less often used, especially in dynamic task environments. The application of spectral analysis techniques of heart rate for workload assessment in aviation is illustrated and discussed. Ideally, workload assessment includes real-time or continuous measures to reveal variations in workload as pilots accomplish their tasks. Four studies are discussed that used heart rate measures for the assessment of: (1) training effectiveness; (2) stress of flight instruction; (3) simulator realism; and (4) flight task difficulty. Results indicate that cardiovascular measures are well suited to index different mental states of pilots as well as their dynamic responses to variations in workload.