Potassium-based algorithm allows correction for the hematocrit bias in quantitative analysis of caffeine and its major metabolite in dried blood spots

Although dried blood spot (DBS) sampling is increasingly receiving interest as a potential alternative to traditional blood sampling, the impact of hematocrit (Hct) on DBS results is limiting its final breakthrough in routine bioanalysis. To predict the Hct of a given DBS, potassium (K+) proved to be a reliable marker. The aim of this study was to evaluate whether application of an algorithm, based upon predicted Hct or K+ concentrations as such, allowed correction for the Hct bias. Using validated LC-MS/MS methods, caffeine, chosen as a model compound, was determined in whole blood and corresponding DBS samples with a broad Hct range (0.18-0.47). A reference subset (n = 50) was used to generate an algorithm based on K+ concentrations in DBS. Application of the developed algorithm on an independent test set (n = 50) alleviated the assay bias, especially at lower Hct values. Before correction, differences between DBS and whole blood concentrations ranged from -29.1 to 21.1 %. The mean difference, as obtained by Bland-Altman comparison, was -6.6 % (95 % confidence interval (CI), -9.7 to -3.4 %). After application of the algorithm, differences between corrected and whole blood concentrations lay between -19.9 and 13.9 % with a mean difference of -2.1 % (95 % CI, -4.5 to 0.3 %). The same algorithm was applied to a separate compound, paraxanthine, which was determined in 103 samples (Hct range, 0.17-0.47), yielding similar results. In conclusion, a K+-based algorithm allows correction for the Hct bias in the quantitative analysis of caffeine and its metabolite paraxanthine

Relationships Between Chemoreflex Responses, Sleep Quality, and Hematocrit in Andean Men and Women.

Andean highlanders are challenged by chronic hypoxia and many exhibit elevated hematocrit (Hct) and blunted ventilation compared to other high-altitude populations. While many Andeans develop Chronic Mountain Sickness (CMS) and excessive erythrocytosis, Hct varies markedly within Andean men and women and may be driven by individual differences in ventilatory control and/or sleep events which exacerbate hypoxemia. To test this hypothesis, we quantified relationships between resting ventilation and ventilatory chemoreflexes, sleep desaturation, breathing disturbance, and Hct in Andean men and women. Ventilatory measures were made in 109 individuals (n = 63 men; n = 46 women), and sleep measures in 45 of these participants (n = 22 men; n = 23 women). In both men and women, high Hct was associated with low daytime SpO2 (p < 0.001 and p < 0.002, respectively) and decreased sleep SpO2 (mean, nadir, and time <80%; all p < 0.02). In men, high Hct was also associated with increased end-tidal PCO2 (p < 0.009). While ventilatory responses to hypoxia and hypercapnia did not predict Hct, decreased hypoxic ventilatory responses were associated with lower daytime SpO2 in men (p < 0.01) and women (p < 0.009) and with lower nadir sleep SpO2 in women (p < 0.02). Decreased ventilatory responses to CO2 were associated with more time below 80% SpO2 during sleep in men (p < 0.05). The obstructive apnea index and apnea-hypopnea index also predicted Hct and CMS scores in men after accounting for age, BMI, and SpO2 during sleep. Finally, heart rate response to hypoxia was lower in men with higher Hct (p < 0.0001). These data support the idea that hypoventilation and decreased ventilatory sensitivity to hypoxia are associated with decreased day time and nighttime SpO2 levels that may exacerbate the stimulus for erythropoiesis in Andean men and women. However, interventional and longitudinal studies are required to establish the causal relationships between these associations

Outcomes of haploidentical stem cell transplantation for chronic lymphocytic leukemia: a retrospective study on behalf of the chronic malignancies working party of the EBMT

Allogeneic hematopoietic stem cell transplantation (HCT) may result in long-term disease control in high-risk chronic lymphocytic leukemia (CLL). Recently, haploidentical HCT is gaining interest because of better outcomes with post-transplantation cyclophosphamide (PTCY). We analyzed patients with CLL who received an allogeneic HCT with a haploidentical donor and whose data were available in the EBMT registry. In total 117 patients (74% males) were included; 38% received PTCY as GVHD prophylaxis. For the whole study cohort OS at 2 and 5 yrs was 48 and 38%, respectively. PFS at 2 and 5 yrs was 38 and 31%, respectively. Cumulative incidence (CI) of NRM in the whole group at 2 and 5 years were 40 and 44%, respectively. CI of relapse at 2 and 5 yrs were 22 and 26%, respectively. All outcomes were not statistically different in patients who received PTCY compared to other types of GVHD prophylaxis. In conclusion, results of haploidentical HCT in CLL seem almost identical to those with HLA-matched donors. Thereby, haploidentical HCT is an appropriate alternative in high risk CLL patients with a transplant indication but no available HLA-matched donor. Despite the use of PTCY, the CI of relapse seems not higher than observed after HLA-matched HCT

Addressing Intimate Partner Violence Among Female Clients Accessing HIV Testing and Counseling Services: Pilot Testing Tools in Rakai, Uganda.

The World Health Organization recommends that HIV counseling and testing (HCT) programs implement strategies to address how intimate partner violence (IPV) influences women's ability to protect themselves from and seek care and treatment for HIV infection. We discuss the process used to adapt a screening and brief intervention (SBI) for female clients of HCT services in Rakai, Uganda-a setting with high prevalence of both HIV and IPV. By outlining our collaborative process for adapting and implementing the SBI in Rakai and training counselors for its use, we hope other HCT programs will consider replicating the approach in their settings

HIV counselling and testing in secondary schools: what students want

Background: HIV counselling and testing (HCT) is an essential element in the response to the HIV epidemic. There are still major research gaps about the best ways to provide HCT, especially to the youth, and school-based HCT is a model that has been suggested. To make HCT youth friendly and to enhance access to the service, the particular needs of the youth need to be addressed. Aim: To explore the expressed needs of students about school-based HCT service provision. Method: The study was conducted in 6 secondary schools in Cape Town where a mobile HCT service is provided by a non-governmental organisation. In each school, two mixed gender focus groups were held, one with grades 8 and 9 students and one with grades 10 and 11. A total of 91 students aged 13-21 were involved. The focus groups were conducted in the students' home language. All groups were audio-recorded, transcribed verbatim and translated into English. Results: Content data analysis was done and the following themes emerged: (1) Where the students want HCT to be done, (2) How they want HCT to be done and (3) Who should do the counselling. Most students want HCT to be provided in schools on condition that their fears and expressed needs are taken into account. They raised concerns regarding privacy and confidentiality, and expressed the need to be given information regarding HCT before testing is done. They wanted staff providing the service to be experienced and trained to work with youth, and they wanted students who tested positive to be followed up and supported. Conclusion: To increase youth utilisation of the HCT service, their expressed needs should be taken into account when developing a model for school-based HCT

Shikimate hydroxycinnamoyl transferase (HCT) activity assays in Populus nigra

Lignin is a complex phenolic polymer deposited in secondarily-thickened plant cell walls. The polymer is mainly derived from the three primary monolignols: p-coumaryl, coniferyl and sinapyl alcohol which give rise to p-hydroxyphenyl, guaiacyl and syringyl units (H, G and S units, respectively) when coupled into the polymer. The building blocks differ in their degree of methoxylation and their biosynthetic pathway is catalyzed by more than 10 enzymes. HCT plays a crucial role by channeling the phenylpropanoids towards the production of coniferyl and sinapyl alcohols. Interestingly, HCT has been reported to be implicated in the pathway both upstream and downstream of the 3-hydroxylation of the aromatic ring of p-coumaroyl shikimate (Figure 1) (Hoffmann et al., 2003; Hoffmann et al., 2004; Vanholme et al., 2013b). These features highlight the importance of developing an assay to reliably measure HCT activity in planta. Here, we describe a UPLC-MS-based method for the analysis of HCT activity in xylem total protein extracts of Populus nigra, which can be adapted to other woody and herbaceous plant species. The protocol was initially described in Vanholme et al. (2013a)

Estimating plasma volume in neonatal Holstein calves fed one or two feedings of a lacteal-based colostrum replacer using Evans blue dye and hematocrit values at various time points.

Twenty-eight Holstein calves were blocked by birth date and randomly assigned to one of two treatments to investigate the effect of colostrum replacer (CR) feeding regimen on plasma volume (PV). Treatments were: 1) one feeding of CR (C1; 3L of reconstituted CR 675 g of powder providing 184.5 g of IgG at birth) or 2) two feedings of CR (C2; 2L of reconstituted CR at birth and 1 L of reconstituted CR at six h). By 6 h of age, all calves had received 3L of CR providing 184.5 g of IgG. Plasma volume was estimated at six, 12, 18, and 24 h after birth using Evans blue dye (EBD). No treatment effects were noted at any time points (P \u3e 0.05). Mean PV for all calves regardless of treatment at six, 12, 18, and 24 h were 78.6, 89.2, 83.9, and 90.7 mL kg-1 of BW, respectively. Plasma volume was correlated with hematocrit (HCT), initial HCT, and treatment. Hematocrit was correlated with PV, initial HCT, and body weight. Hematocrit for six, 12, 18 and 24 h after birth can be predicted with an initial precolostral HCT determination

A novel, nondestructive, dried blood spot-based hematocrit prediction method using noncontact diffuse reflectance spectroscopy

Dried blood spot (DBS) sampling is recognized as a valuable alternative sampling strategy both in research and in clinical routine. Although many advantages are associated with DBS sampling, its more widespread use is hampered by several issues, of which the hematocrit effect on DBS-based quantitation remains undoubtedly the most widely discussed one. Previously, we developed a method to derive the approximate hematocrit from a nonvolumetrically applied DBS based on its potassium content. Although this method yielded good results and was straightforward to perform, it was also destructive and required sample preparation. Therefore, we now developed a nondestructive method which allows to predict the hematocrit of a DBS based on its hemoglobin content, measured via noncontact diffuse reflectance spectroscopy. The developed method was thoroughly validated. A linear calibration curve was established after log/log transformation. The bias, intraday and interday imprecision of quality controls at three hematocrit levels and at the lower and upper limit of quantitation (0.20 and 0.67, respectively) were less than 11%. In addition, the influence of storage and the volume spotted was evaluated, as well as DBS homogeneity. Application of the method to venous DBSs prepared from whole blood patient samples (n = 233) revealed a good correlation between the actual and the predicted hematocrit. Limits of agreement obtained after Bland and Altman analysis were -0.076 and. +0.018. Incurred sample reanalysis demonstrated good method reproducibility. In conclusion, mere scanning of a DBS suffices to derive its approximate hematocrit, one of the most important variables in DBS analysis

Particle based modeling and simulation of the red blood cell Infected by malaria-mechanism of the margination of the Infected red blood cell

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.Motion and distribution of red blood cells in blood microvessels depend on vessel diameter, hematocrit (Hct), RBCs deformability and other factors. Migration of deformable red blood cells (RBCs) to the center of microvessels and away from the wall leads to the formation of cell-free layer (CFL). Few experiments or simulations considered the effects of motion and interaction of RBCs on CFL thickness. We employ a meshless (particle) method to model microvascular blood flow. An efficient parallel algorithm is developed for large-scale simulations of blood flow in microvessels. Using the developed method, we analyze the change in RBCs shape and RBCs distribution and also thickness of CFL in a variety of vessel sizes and Hct conditions. The results indicate that the CFL thickness increases when the vessel size increases or Hct decreases, which is in good agreement with previous experimental results. We also show change on RBCs shape and distribution for different microvessels diameter and Hct conditions