Levitt's CO breath test in the differential diagnosis of chronic isolated hyperbilirubinemia.

A key component of the differential diagnosis of isolated hyperbilirubinemia (HB) is distinguishing between hemolytic and non-hemolytic types. Routine hemolysis screening markers have unsatisfactory sensitivity and specificity. Erythrocyte (RBC) lifespan shortening, the gold standard marker of hemolysis, is seldomly measured due to the cumbersome and protracted nature of standard methods. A new Levitt's CO breath test method may enable simple, rapid RBC lifespan measurement. In this pilot prospective diagnostic study, Levitt's CO breath test was evaluated to discriminate hemolytic from non-hemolytic HB in adults. One hundred and thirty eligible non-smoking adult patients who were aged 18 or older, referred for chronic (>6 months) isolated HB or had a known diagnosis of isolated HB of a rare cause, were recruited, including 77 with non-hemolytic HB and 53 with hemolytic HB. ROC curve analysis was applied to determine the optimal cutoff for discriminating between hemolytic and non-hemolytic HB, and the performance was calculated. Results showed that the mean RBC lifespan in non-hemolytic HB (93 ± 26 d) was reduced (p= 0.001 vs. normal reference value of 126 d), but longer than that in hemolytic HB (36 ± 17 d;p= 0.001). RBC lifespans did not differ significantly between 26 patients with simple hemolytic HB (32 ± 14 d) and 27 patients with a Gilbert syndrome comorbidity (40 ± 18 d). ROC curve analysis revealed an optimal lifespan cutoff for discriminating between hemolytic and non-hemolytic HB of 60 d (AUC = 0.982), with a diagnostic accuracy of 95.4%, 94.3% sensitivity and 96.1% specificity respectively. These results indicate that Levitt's CO breath test seems to be very sensitive and specific for detecting hemolysis in adult patients with chronic isolated HB, and could enable simple, rapid, and reliable differential diagnosis of isolated HB. A large-scale validation study of the method is warranted.

Red Blood Cell Lifespan Shortening in Patients with Early-Stage Chronic Kidney Disease.

BACKGROUND: Although reduced red blood cell (RBC) lifespan has been reported to be a contributory factor to anemia in patients with end-stage chronic kidney disease (CKD), there are limited data regarding RBC lifespan in early-stage CKD. Serum erythropoietin (EPO) is considered a primary causative factor of renal anemia. The aims of this study were to compare the RBC lifespan, serum EPO levels, and other renal anemia indicators across CKD-stage groups of patients and to analyze the impacts of etiological factors on renal anemia. METHODS: A cohort of 74 non-smoking patients with CKD were enrolled, including 15 in stage 1, 18 in stage 2, 15 in stage 3, 15 in stage 4, and 11 in stage 5. RBC lifespan was determined by CO breath tests. Potential correlations of hemoglobin (Hb) concentration with RBC lifespan, reticulocyte count (Ret), and levels of EPO, ferritin, folic acid, and vitamin B12 were analyzed. RESULTS: CKD progression was associated with decreases in (Hb) and RBC lifespan. RBC lifespan durations in CKD stages 1-5 were 122 ± 50, 112 ± 26, 90 ± 32, 88 ± 28, and 60 ± 24 days, respectively. RBC lifespan means for the stage 3, 4 and 5 groups were significantly shorter than those for the stage 1 and 2 groups. Serum EPO did not differ significantly between the CKD stage groups. (Hb) correlated directly with RBC lifespan (r = 0.372, p = 0.002) and Ret (r = 0.308, p = 0.011), but did not correlate with serum EPO, ferritin, folic acid, or vitamin B12 levels. CONCLUSIONS: Reduced RBC lifespan in early-stage CKD, demonstrated in this study, suggests that increased RBC destruction may play a more important etiological role in renal anemia than other indicators in patients with CKD.

Effects of Ginkgo biloba extract EGb761 on neural differentiation of stem cells offer new hope for neurological disease treatment.

Stem cell transplantation has brought new hope for the treatment of neurological diseases. The key to stem cell therapy lies in inducing the specific differentiation of stem cells into nerve cells. Because the differentiation of stem cells in vitro and in vivo is affected by multiple factors, the final differentiation outcome is strongly associated with the microenvironment in which the stem cells are located. Accordingly, the optimal microenvironment for inducing stem cell differentiation is a hot topic. EGb761 is extracted from the leaves of the Ginkgo biloba tree. It is used worldwide and is becoming one of the focuses of stem cell research. Studies have shown that EGb761 can antagonize oxygen free radicals, stabilize cell membranes, promote neurogenesis and synaptogenesis, increase the level of brain-derived neurotrophic factors, and replicate the environment required during the differentiation of stem cells into nerve cells. This offers the possibility of using EGb761 to induce the differentiation of stem cells, facilitating stem cell transplantation. To provide a comprehensive reference for the future application of EGb761 in stem cell therapy, we reviewed studies investigating the influence of EGb761 on stem cells. These started with the composition and neuropharmacology of EGb761, and eventually led to the finding that EGb761 and some of its important components play important roles in the differentiation of stem cells and the protection of a beneficial microenvironment for stem cell transplantation.

Rapid CO breath test screening of drugs for protective effects on ribavirin-induced hemolysis in a rabbit model: a pilot study.

Hemolytic anemia is a major side effect of ribavirin antiviral treatment for chronic hepatitis C. Ribavirin dose reduction may compromise the antiviral response and erythropoietin can take several weeks to alleviate anemia. The purpose of the present study was to screen potentially protective drugs against ribavirin-induced hemolytic anemia in a rabbit model, using our modified CO breath test for measuring erythrocyte (RBC) lifespan, the gold standard diagnostic index of hemolysis. Fifteen rabbits were divided randomly into five groups (N = 3/group): one vehicle control group, one ribavirin (only)-treated (RBV) group, and three groups initially treated with ribavirin only, followed by a combination of ribavirin with prednisone (RBV + Pred), polyene phosphatidyl choline (RBV + PPC), or reduced glutathione (RBV + GSH). RBC lifespan was calculated from accumulated CO measured in a closed rebreath apparatus, blood volume measured by the Evan's blue dye (EBD) dilution test, and hemoglobin concentration data. The RBC lifespan was normal in the vehicle control group (44-60 d), but reduced significantly in all of the ribavirin-treated groups before the addition of screened drugs (17-35 d). RBC lifespan rebounded significantly with the addition of glutathione, but not with the addition of prednisone or polyene phosphatidyl choline. A similar overall drug effect pattern was seen in the hemoglobin concentration and reticulocyte count data. In conclusion, the results of this pilot study indicate that reduced glutathione can attenuate ribavirin-induced hemolytic anemia, and that the RBC lifespan measured with our modified rapid CO breath test is feasible and reliable for use in animal studies.