Severe Painful Vaso-Occlusive Crises and Mortality in a Contemporary Adult Sickle Cell Anemia Cohort Study

Background

Frequent painful vaso-occlusive crises (VOCs) were associated with mortality in the Cooperative Study of Sickle Cell Disease (CSSCD) over twenty years ago. Modern therapies for sickle cell anemia (SCA) like hydroxyurea are believed to have improved overall patient survival. The current study sought to determine the relevance of the association between more frequent VOCs and death and its relative impact upon overall mortality compared to other known risk factors in a contemporary adult SCA cohort.

Methods

Two hundred sixty four SCA adults were assigned into two groups based on patient reported outcomes for emergency department (ED) visits or hospitalizations for painful VOC treatment during the 12 months prior to evaluation.

Results

Higher baseline hematocrit (p = 0.0008), ferritin (p = 0.005), and HDL cholesterol (p = 0.01) were independently associated with 1 or more painful VOCs requiring an ED visit or hospitalization for acute pain. During a median follow-up of 5 years, mortality was higher in the ED visit/hospitalization group (relative risk [RR] 2.68, 95% CI 1.1-6.5, p = 0.03). Higher tricuspid regurgitatant jet velocity (TRV) (RR 2.41, 95% CI 1.5-3.9, p < 0.0001), elevated ferritin (RR 4.00, 95% CI 1.8-9.0, p = 0.001) and lower glomerular filtration rate (RR=2.73, 95% CI 1.6-4.6, p < 0.0001) were also independent risk factors for mortality.

Conclusions

Severe painful VOCs remain a marker for SCA disease severity and premature mortality in a modern cohort along with other known risk factors for death including high TRV, high ferritin and lower renal function. The number of patient reported pain crises requiring healthcare utilization is an easily obtained outcome that could help to identify high risk patients for disease modifying therapies.

Trial Registration

ClinicalTrials.gov NCT00011648 http://clinicaltrials.gov/     

Effects of medium viscosity on kinetics of the enzymatic reaction catalyzed by bacterial RNase

Effects of medium viscosity on kinetic parameters of poly(U) hydrolysis catalyzed by RNase from Bac. intermedius 7P (binase) were studied in solutions of sucrose (4-50 wt. %) and glycerol (35-62 wt. %) in Tris--sodium acetate buffer (pH 7.5) at 25 degreesC. The rate constant of reaction kcat was practically unchanged over a wide range of viscosities (1-15 cP for sucrose and 2.5-3 cP for glycerol). In glycerol solutions, kcat slightly increased with viscosity increase from 4 to 10 cP. Addition of NaCl to the buffer medium resulted in an inhibitory effect of Na+ on kcat, prevented by 50% sucrose or 60% glycerol. It is concluded that binase-catalyzed poly(U) cleavage occurs through a "tense"-substrate mechanism, similarly to reactions catalyzed by alpha-chymotrypsin, trypsin, and laccase.     

A web server to locate periodicities in a sequence

Summary : FT is a tool written in C++, which implements the Fourier analysis method to locate periodicities in aminoacid or DNA sequences. It is provided for free public use on a WWW server with a Java interface. Availability : The server address is http://o2.db. uoa.gr/FT Contact : shamodr@atlas.uoa.gr      

Hatching asynchrony and brood reduction influence immune response in Common Kestrel Falco tinnunculus nestlings

The onset of incubation before the end of laying imposes asynchrony at hatching and, therefore, a size hierarchy in the brood. It has been argued that hatching asynchrony might be a strategy to improve reproductive output in terms of quality or quantity of offspring. However, little is known about the mediating effect of hatching asynchrony on offspring quality when brood reduction occurs. Here, we investigate the relationship between phenotypic quality and hatching asynchrony in Common Kestrel Falco tinnunculus nestlings in Spain. Hatching asynchrony did not increase breeding success or nestling quality. Furthermore, hatching asynchrony and brood reduction had different effects on nestlings’ phytohaematogglutinin (PHA)‐mediated immune response and nestling growth. In asynchronous and reduced broods (in which at least one nestling died), nestlings showed a stronger PHA‐mediated immune response and tended to have a smaller body size compared with nestlings raised in synchronous and reduced broods. When brood reduction occurred in broods hatched synchronously, there was no effect on nestling size, but nestlings had a relatively poor PHA‐mediated immune response compared with nestlings raised in asynchronous and reduced broods. We suggest that resources for growth can be directed to immune function only in asynchronously hatched broods, resulting in improved nestling quality, as suggested by their immune response. We also found that males produced a greater PHA‐mediated immune response than females only in brood‐reduced nests without any effect on nestling size or condition, suggesting that females may trade off immune activities and body condition, size or weight. Overall, our results suggest that hatching pattern and brood reduction may mediate resource allocation to different fitness traits. They also highlight that the resolution of immune‐related trade‐offs when brood reduction occurs may differ between male and female nestlings.     

Risk Factors for Death in 632 Patients with Sickle Cell Disease in the United States and United Kingdom

Background

The role of pulmonary hypertension as a cause of mortality in sickle cell disease (SCD) is controversial.

Methods and Results

We evaluated the relationship between an elevated estimated pulmonary artery systolic pressure and mortality in patients with SCD. We followed patients from the walk-PHaSST screening cohort for a median of 29 months. A tricuspid regurgitation velocity (TRV)≥3.0 m/s cuttof, which has a 67–75% positive predictive value for mean pulmonary artery pressure ≥25 mm Hg was used. Among 572 subjects, 11.2% had TRV≥3.0 m/sec. Among 582 with a measured NT-proBNP, 24.1% had values ≥160 pg/mL. Of 22 deaths during follow-up, 50% had a TRV≥3.0 m/sec. At 24 months the cumulative survival was 83% with TRV≥3.0 m/sec and 98% with TRV<3.0 m/sec (p<0.0001). The hazard ratios for death were 11.1 (95% CI 4.1–30.1; p<0.0001) for TRV≥3.0 m/sec, 4.6 (1.8–11.3; p = 0.001) for NT-proBNP≥160 pg/mL, and 14.9 (5.5–39.9; p<0.0001) for both TRV≥3.0 m/sec and NT-proBNP≥160 pg/mL. Age >47 years, male gender, chronic transfusions, WHO class III–IV, increased hemolytic markers, ferritin and creatinine were also associated with increased risk of death.

Conclusions

A TRV≥3.0 m/sec occurs in approximately 10% of individuals and has the highest risk for death of any measured variable.

The study is registered in ClinicalTrials.gov with identifier

{"type":"clinical-trial","attrs":{"text":"NCT00492531","term_id":"NCT00492531"}}NCT00492531     

Fine‐scale bird monitoring from light unmanned aircraft systems

Unmanned aircraft systems (UAS) are remote‐controlled devices capable of collecting information from difficult‐to‐access places while minimizing disturbance. Although UAS are increasingly used in many research disciplines, their application to wildlife research remains to be explored in depth. Here, we report on the use of a small UAS to monitor temporal changes in breeding population size in a Black‐headed Gull Chroicocephalus ridibundus colony. This method makes it possible to obtain georeferenced data on nest locations without causing colony disturbance, which would not otherwise be possible via direct ground observations.     

Spectral properties of thioflavin T in solvents with different dielectric properties and in a fibril-incorporated form

The increase in the solvent polarity induces a significant shift of the long-wavelength absorption band of the thioflavin T (ThT) to the shorter wavelengths. This is due to the fact that the positive charge of the ThT molecule (Z = +1e) is unequally and very differently distributed between the benzthiazole and aminobenzene rings in the ground and excited states. Therefore, ThT ground state is stabilized by the orientational interactions of the polar solvent dipoles with the positively charged ThT fragments, whereas the configuration of the solvation shell of the ThT molecule in the excited Franck-Condon state is likely far from being equilibrium. ThT absorption spectrum has the shortest (412 nm) and the longest (450 nm) wavelengths in water and in water being incorporated to the amyloid fibrils, respectively. Intriguingly, the position of the ThT fluorescence spectrum depends on the polarity of solvent to a significantly lesser degree than its absorption spectrum: being excited at 440 nm, ThT has emission with maxima at 493 and 478 nm in water and fibrils, respectively. This can be due to the fact that, in the excited state, the rotational oscillations of the ThT fragments relative to each other prevent establishing equilibrium with the solvent and fluorescence occurs from the partially equilibrium excited stated to the partially equilibrium ground state. For the fibril-incorporated ThT, the maximum of the fluorescence excitation spectrum coincides with the maximum of the long wavelength absorption band (450 nm), whereas for ThT in aqueous and alcohol solutions, additional short-wavelength bands of fluorescence and fluorescence excitation spectra were described (Naiki et al. Anal. Biochem. 1989, 177, 244-249; Le Vine Methods Enzymol. 1999, 309, 274-284). These bands could result either from some fluorescent admixtures (including free benzthiazole and aminobenzene) or from the specific ThT conformers in which benzthiazole and aminobenzene rings, being oriented at phi angle close to 90 or 270 degrees, serve as independent chromophores. On the basis of the results of the quantum-chemical calculations, it is proposed that at phi = 90 degrees (270 degrees), the relatively low barrier (only 700 cm-1) of the internal rotation of the benzthiazole and aminobenzene rings relative to each other gives rise to a subpopulation of ThT molecules possessing a violated system of the pi-conjugated bonds of the benzthiazole and aminobenzene rings.     

Hydroxyurea-Increased Fetal Hemoglobin Is Associated with Less Organ Damage and Longer Survival in Adults with Sickle Cell Anemia

Background

Adults with sickle cell anemia (HbSS) are inconsistently treated with hydroxyurea.

Objectives

We retrospectively evaluated the effects of elevating fetal hemoglobin with hydroxyurea on organ damage and survival in patients enrolled in our screening study between 2001 and 2010.

Methods

An electronic medical record facilitated development of a database for comparison of study parameters based on hydroxyurea exposure and dose. This study is registered with ClinicalTrials.gov, number NCT00011648.

Results

Three hundred eighty-three adults with homozygous sickle cell disease were analyzed with 59 deaths during study follow-up. Cox regression analysis revealed deceased subjects had more hepatic dysfunction (elevated alkaline phosphatase, Hazard Ratio = 1.005, 95% CI 1.003–1.006, p<0.0.0001), kidney dysfunction (elevated creatinine, Hazard Ratio = 1.13, 95% CI 1.00–1.27, p = 0.043), and cardiopulmonary dysfunction (elevated tricuspid jet velocity on echocardiogram, Hazard Ratio = 2.22, 1.23–4.02, p = 0.0082). Sixty-six percent of subjects were treated with hydroxyurea, although only 66% of those received a dose within the recommended therapeutic range. Hydroxyurea use was associated with improved survival (Hazard Ratio = 0.58, 95% CI 0.34–0.97, p = 0.040). This effect was most pronounced in those taking the recommended dose of 15–35 mg/kg/day (Hazard Ratio 0.36, 95% CI 0.17–0.73, p = 0.0050). Hydroxyurea use was not associated with changes in organ function over time. Further, subjects with higher fetal hemoglobin responses to hydroxyurea were more likely to survive (p = 0.0004). While alkaline phosphatase was lowest in patients with the best fetal hemoglobin response (95.4 versus 123.6, p = 0.0065 and 96.1 versus 113.6U/L, p = 0.041 at first and last visits, respectively), other markers of organ damage were not consistently improved over time in patients with the highest fetal hemoglobin levels.

Conclusions

Our data suggest that adults should be treated with the maximum tolerated hydroxyurea dose, ideally before organ damage occurs. Prospective studies are indicated to validate these findings.     

Haptoglobin and CCR2 receptor expression in ovarian cancer cells that were exposed to ascitic fluid: Exploring a new role of haptoglobin in the tumoral microenvironment

Haptoglobin (Hp) is an acute-phase protein that is produced by the liver to capture the iron that is present in the blood circulation, thus avoiding its accumulation in the blood. Moreover, Hp has been detected in a wide variety of tissues, in which it performs various functions. In addition, this protein is considered a potential biomarker in many diseases, such as cancer, including ovarian carcinoma; however, its participation in the cancerous processes has not yet been determined. The objective of this work was to demonstrate the expression of Hp and its receptor CCR2 in the ovarian cancer cells and its possible involvement in the process of cell migration through changes in the rearrangement of the actin cytoskeleton using western blot and wound-healing assays and confirming by confocal microscopy. Ovarian cancer cells express both Hp and its receptor CCR2 but only after exposure to ascitic fluid, inducing moderated cell migration. However, when the cells are exposed to exogenous Hp, the expression of CCR2 is induced together with drastic changes in the actin cytoskeleton rearrangement. At the same time, Hp induced cell migration in a much more efficient manner than did ascitic fluid. These effects were blocked when the CCR2 synthetic antagonist RS102895 was used to pretreat the cells. These results suggest that Hp-induced changes in the cell morphology, actin cytoskeleton structure, and migration ability of tumor cells, is possibly “preparing” these cells for the potential induction of the metastatic phenotype.