A single-tube osmotic fragility test has been proposed for thalassemia screening with a range of different concentrations of saline having been employed. We have compared the sensitivity and specificity of 0.32%, 0.34%, and 0.36% buffered saline, and on the basis of our findings, recommend the use of 0.36% saline. This gave definitely positive or equivocal results in 81 of 85 patients with b thalassemia trait and in 4 of 4 with a 0 thalassemia trait. There were 14% false positive results in hematologically normal patients and 81% of the samples from patients with various variant hemoglobins gave positive results. The sensitivity was 95% and specificity 86%. The single-tube osmotic fragility test is potentially useful in under-resourced laboratories although it cannot replace automated red cell indices using electronic counters. Am.

There is a need to develop markers for early detection of organ failure in shock that can be noninvasively measured at point of care. We explore here the use of volatile organic compounds (VOCs) in expired air in a rat peritonitis shock model. Expired breath samples were collected into Tedlar gas bags and analyzed by standardized gas chromatography. The gas chromatograms were digitally analyzed for presence of peak amounts over a range of Kovach indices. Following the induction of peritonitis, selected volatile compounds were detected within about 1 h, which remained at elevated amounts over a 6 h observation period. These VOCs were not present in control animals without peritonitis. Comparisons with know VOCs indicate that they include 1,4-diaminobutane and trimethylamine N-oxide. When pancreatic digestive proteases were blocked with tranexamic acid in the intestine and peritoneum, a procedure that serves to reduce organ failure in shock, the amounts of VOCs in the breath decreased spontaneously to control values without peritonitis. These results indicate that peritonitis shock is accompanied by development of volatile organic compounds that may be generated by digestive enzymes in the small intestine. VOCs may serve as indicators for detection of early forms of autodigestion by digestive proteases.

Metabolic disease is accompanied by a range of cellular defects (“comorbidities”) whose origin is uncertain. To investigate this pathophysiological phenomenon we used the Spontaneously Hypertensive Rat (SHR), which besides an elevated arterial blood pressure also has many other comorbidities, including a defective glucose and lipid metabolism. We have shown that this model of metabolic disease has elevated plasma matrix metalloproteinase (MMP) activity, which cleaves the extracellular domain of membrane receptors. We hypothesize here that the increased MMP activity also leads to abnormal cleavage of the scavenger receptor and fatty acid transporter CD36. To test this idea, chronic pharmaceutical MMP inhibition (CGS27023A) of the SHR and its normotensive control, the Wistar Kyoto Rat (WKY), was used to determine if inhibition of MMP activity serves to maintain CD36 receptor density and function. Surface density of CD36 on macrophages from the heart, spleen, and liver was determined in WKY, SHR, CGS-treated WKY (CGS WKY), and CGS-treated SHR (CGS SHR) by immunohistochemistry with an antibody against the CD36 ectodomain. The extracellular CD36 density was lower in SHR heart and spleen macrophages compared to that in the WKY. MMP inhibition by CGS served to restore the reduced CD36 density on SHR cardiac and splanchnic macrophages to levels of the WKY. To examine CD36 function, culture assays with murine macrophages (RAW 264.7) after incubation in fresh WKY or SHR plasma were used to test for adhesion of light-weight donor red blood cell (RBC) by CD36. This form of RBC adhesion to macrophages was reduced after incubation in SHR compared WKY plasma. Analysis of the supernatant macrophage media by Western blot shows a higher level of CD36 extracellular protein fragments following exposure to SHR plasma compared to WKY. MMP inhibition in the SHR plasma compared to untreated plasma, served to increase the RBC adhesion to macrophages and decrease the number of receptor fragments in the macrophage media. In conclusion, these studies bring to light that plasma in the SHR model of metabolic disease has an unchecked MMP degrading activity which causes cleavage of a variety of membrane receptors, including CD36, which attenuates several cellular functions typical for the metabolic disease, including RBC adhesion to the scavenger receptor CD36. In addition to other cell dysfunctions chronic MMP inhibition restores CD36 in the SHR.

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