Socio-economic burden of TB and its impact on child contacts in The Gambia

OBJECTIVE

To determine the social impact of adult TB on child household contacts living in the Greater Banjul Area, The Gambia.

METHODS

This was a prospective observational cohort study among adults (≥18 years) starting treatment for drug-susceptible pulmonary TB between June 2019 and July 2021 who reported having at least one child household contact. We collected data from 51 adults and 180 child contacts at the start of TB treatment (baseline) and again at 6 months of treatment. Participants were asked about expenses for school fees, healthcare, festivities and food security of child contacts.

RESULTS

While school attendance of the child contacts remained largely unaffected, there was a significant drop in school performance at 6 months (P < 0.001). Furthermore, child contacts faced significant food insecurity in terms of food quantity and variety available, with up to a four-fold increase in some instances at 6 months compared to baseline (P < 0.001).

CONCLUSION

Child contacts face a potential decline in school performance and risk of food insecurity. While a plethora of work is being undertaken to alleviate costs of care for TB patients, further emphasis is needed to ensure educational and social prosperity for child contacts, as adults with TB have socio-economic implications for the wider household.

Patient-reported health outcomes of SARS-CoV-2-tested patients presenting to emergency departments: a propensity score-matched prospective cohort study

OBJECTIVE

This study aimed to compare the long-term physical and mental health outcomes of matched severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-positive and SARS-CoV-2-negative patients controlling for seasonal effects.

STUDY DESIGN

This was a retrospective cohort study.

METHODS

This study enrolled patients presenting to emergency departments participating in the Canadian COVID-19 Emergency Department Rapid Response Network. We enrolled consecutive eligible consenting patients who presented between March 1, 2020, and July 14, 2021, and were tested for SARS-CoV-2. Research assistants randomly selected four site and date-matched SARS-CoV-2-negative controls for every SARS-CoV-2-positive patient and interviewed them at least 30 days after discharge. We used propensity scores to match patients by baseline characteristics and used linear regression to compare Veterans RAND 12-item physical health component score (PCS) and mental health component scores (MCS), with higher scores indicating better self-reported health.

RESULTS

We included 1170 SARS-CoV-2-positive patients and 3716 test-negative controls. The adjusted mean difference for PCS was 0.50 (95% confidence interval [CI]: -0.36, 1.36) and -1.01 (95% CI: -1.91, -0.11) for MCS. Severe disease was strongly associated with worse PCS (β = -7.4; 95% CI: -9.8, -5.1), whereas prior mental health illness was strongly associated with worse MCS (β = -5.4; 95% CI: -6.3, -4.5).

CONCLUSION

Physical health, assessed by PCS, was similar between matched SARS-CoV-2-positive and SARS-CoV-2-negative patients, whereas mental health, assessed by MCS, was worse during a time when the public experienced barriers to care. These results may inform the development and prioritization of support programs for patients.

The household economic burden of drug-susceptible TB diagnosis and treatment in The Gambia

OBJECTIVE: To determine the costs and catastrophic costs incurred by drug-susceptible (DS) pulmonary TB patients in The Gambia.METHODS: This observational study collected cost and socio-economic data using a micro-costing approach from the household perspective from 244 adult DS-TB patients with pulmonary TB receiving treatment through the national treatment programme in The Gambia. We used data collected between 2017 and 2020 using an adapted version of the WHO generic patient cost survey instrument to estimate costs and the proportion of patients experiencing catastrophic costs (≥20% of household income).RESULTS: The mean total cost of the TB episode was $104.11 (2018 USD). Direct costs were highest before treatment ($22.93). Indirect costs accounted for over 50% of the entire episode costs. Using different income estimation approaches and catastrophic cost thresholds, 0.4-75% of participants encountered catastrophic costs, showing the variability of results given the different assumptions we utilised.CONCLUSIONS: We show that despite the benefits of free TB care and treatment, DS-TB patients still incur substantial direct and indirect costs, and cases of impoverishing expenditure varied vastly depending on the income estimation approaches used.

Vitamin D and Type 1 Diabetes Risk: A Systematic Review and Meta-Analysis of Genetic Evidence

Several observational studies have examined vitamin D pathway polymorphisms and their association with type 1 diabetes (T1D) susceptibility, with inconclusive results. We aimed to perform a systematic review and meta-analysis assessing associations between selected variants affecting 25-hydroxyvitamin D [25(OH)D] and T1D risk. We conducted a systematic search of Medline, Embase, Web of Science and OpenGWAS updated in April 2021. The following keywords “vitamin D” and/or “single nucleotide polymorphisms (SNPs)” and “T1D” were selected to identify relevant articles. Seven SNPs (or their proxies) in six genes were analysed: CYP2R1 rs10741657, CYP2R1 (low frequency) rs117913124, DHCR7/NADSYN1 rs12785878, GC rs3755967, CYP24A1 rs17216707, AMDHD1 rs10745742 and SEC23A rs8018720. Seven case-control and three cohort studies were eligible for quantitative synthesis (n = 10). Meta-analysis results suggested no association with T1D (range of pooled ORs for all SNPs: 0.97–1.02; p > 0.01). Heterogeneity was found in DHCR7/NADSYN1 rs12785878 (I²: 64.8%, p = 0.02). Sensitivity analysis showed exclusion of any single study did not alter the overall pooled effect. No association with T1D was observed among a Caucasian subgroup. In conclusion, the evidence from the meta-analysis indicates a null association between selected variants affecting serum 25(OH)D concentrations and T1D.

925Ethnic differences and determinants of vitamin D deficiency in the UK Biobank

Background

While controversy remains regarding optimal vitamin D status, the public health relevance of true vitamin D deficiency is undisputed. There are few contemporary cross-ethnic studies investigating the prevalence and determinants of very low 25-hydroxyvitamin D [25(OH)D] concentrations.

Methods

We used data from 440,581 UK Biobank participants, of which 415,903 identified as white European, 7,880 Asian, 7,602 black African, 1,383 Chinese, and 6,473 of mixed ancestry. 25(OH)D concentrations were measured by DiaSorin Liaison XL and deficiency defined as ≤ 25 nmol/L 25(OH)D.

Results

The prevalence of 25(OH)D deficiency was highest among participants of Asian ancestry (57.2% in winter/spring and 50.8% in summer/autumn; followed by black African [38.47%/30.78%], mixed ancestry [36.53%/22.48%], Chinese [33.12%/20.68%] and white European [17.45%/5.90%], P &lt; 1.0E-300). Participants with higher socioeconomic deprivation were more likely to have 25(OH)D deficiency compared to less deprived (P &lt; 1.0E-300 for all comparisons), with the pattern being more apparent among those of white European ancestry and in summer (Pinteraction&lt;6.4E-5 for both). In fully-adjusted analyses, regular consumption of oily fish was effective in mitigating ≤25 nmol/L 25(OH)D deficiency across all ethnicities, whilst outdoor-summer time was less effective for black Africans than white Europeans (OR: 0.89; 95% CI: 0.70, 1.12 and OR: 0.40; 95% CI: 0.38, 0.42, respectively).

Conclusions

Vitamin D deficiency remains an issue throughout the UK, particularly in lower socioeconomic areas and the UK Asian population, half of whom have vitamin D deficiency across seasons.

Key messages

The prevalence of 25(OH)D deficiency in the UK is alarming, with certain ethnic and socioeconomic groups considered particularly vulnerable.

Evidence for supercoughers in an analysis of six tuberculosis cohorts from China, Peru, The Gambia and Uganda

BACKGROUND: It is very difficult to observe tuberculosis (TB) transmission chains and thus, identify superspreaders. We investigate cough duration as a proxy measure of transmission to assess the presence of potential TB superspreaders.DESIGN: We analyzed six studies from China, Peru, The Gambia and Uganda, and determined the distribution of cough duration and compared it with several theoretical distributions. To determine factors associated with cough duration, we used linear regression and boosted regression trees to examine the predictive power of patient, clinical and environmental characteristics.RESULTS: We found within-study heterogeneity in cough duration and strong similarities across studies. Approximately 20% of patients contributed 50% of total cough days, and around 50% of patients contributed 80% of total cough days. The cough duration distribution suggested an initially increasing, and subsequently, decreasing hazard of diagnosis. While some of the exposure variables showed statistically significant associations with cough duration, none of them had a strong effect. Multivariate analyses of different model types did not produce a model that had good predictive power.CONCLUSION: We found consistent evidence for the presence of supercoughers, but no characteristics predictive of such individuals.

The burden of non-TB lung disease presenting to TB clinics in The Gambia: preliminary data in the Xpert® MTB/Rif era

In some low and middle-income countries, 10-20% of patients presenting with a persistent cough have tuberculosis (TB). Once TB is excluded, health service provision for alternative diagnoses is limited. We prospectively studied patients with two Xpert-negative sputum results presenting to a TB clinic in The Gambia. Of 239 patients, 108 did not have TB; 65/102 (6 were lost to follow-up) had alternative diagnoses, 24.6% of which were non-respiratory; 37/102 had no diagnosis, 27.0% of whom were HIV-1-positive; 37.8% had a history of TB and 24.3% smoked. We highlight the need for general health service integration with TB platforms and exploration of non-TB patients with chronic respiratory symptoms.

Contribution of Xpert® MTB/RIF to the diagnosis of pulmonary tuberculosis among TB-exposed children in The Gambia

SETTING

Greater Banjul Area, The Gambia.

OBJECTIVE

To conduct a pragmatic evaluation of the Xpert(®) MTB/RIF assay in the diagnosis of tuberculosis (TB) among child contacts.

DESIGN

In this prospective study, one induced sputum sample was obtained from TB contacts aged <15 years and tested using fluorescent microscopy, culture and Xpert. The diagnostic accuracy of the microbiological tests was evaluated against culture and 'all TB diagnosis and treatment' as separate reference standards.

RESULTS

Using culture as a reference standard, Xpert was positive for Mycobacterium tuberculosis in 6/14 culture-positive and 6/473 culture-negative children, giving a sensitivity and specificity of respectively 42.9% (95%CI 17.7-71.1) and 98.7% (95%CI 97.2-99.5). With 'all TB diagnosis and treatment' as a composite reference standard, combined Xpert and culture tests were positive for M. tuberculosis in 20/62 children with TB disease (32.3%, 95%CI 20.9-45.3), which was comparable to the yield from microscopy, culture and Xpert combined (33.9%, 95%CI 22.3-47.0), but significantly higher than individual yields from each test.

CONCLUSION

The sensitivity of Xpert is low in actively traced child contacts, but a combination of Xpert and mycobacterial culture has incremental benefits for the bacteriological confirmation of TB disease.

Platelet apoptosis and activation in platelet concentrates stored for up to 12 days in plasma or additive solution

BACKGROUND

Several studies suggest that apoptosis of platelets occurs during storage of platelet concentrates (PC). We sought to determine whether storage of PC in additive solution alters levels of apoptosis during storage beyond the current shelf life (5-7 days).

STUDY DESIGN AND METHODS

Pooled buffy coat PC (n = 7) were prepared in either 100% plasma or 70% Composol and stored at 22 °C for 12 days. A third arm of the study stored PC in 100% plasma at 37 °C, which is thought to induce apoptosis. PC were tested for mitochrondrial membrane potential, annexin V binding, microparticles, caspase-3/7 activity and decoy cell death receptor 2, as well as standard platelet quality tests.

RESULTS

Composol units remained ≥pH 6·88, with 36% lower lactate and higher pH vs plasma by day 12 (P < 0·001). Platelet function was better maintained, and activation and apoptotic markers tended to be lower in Composol units towards the end of storage. However, levels of all apoptosis markers assessed were not significantly different in units stored in Composol. Storage at 37 °C saw stronger correlation of apoptotic markers with standard quality tests compared to 22 °C, but loss of correlation of caspase-3/7 activity with other apoptosis markers.

CONCLUSION

We conclude that storage of platelets in 70% Composol vs 100% plasma does not increase the rate of platelet apoptosis. Our data agree with other studies suggesting that platelet apoptosis is sequential to high levels of activation, but share a significant degree of overlap.

Liposomal encapsulated doxorubicin (Caelyx) in the treatment of relapsed aggressive non-Hodgkin's lymphoma: A phase II study

Aggressive non-Hodgkin's lymphoma (NHL), such as diffuse large B-cell lymphoma, can be cured in approximately 50% of cases, but those cases that recur and are not amenable to high-dose chemotherapy rely on palliative chemotherapy to improve symptoms and prolong life. Anthracyclines are associated with a high response rate in aggressive NHL but extended treatment results in cardiotoxicity. Liposomal encapsulated doxorubicin has been shown in other tumor types to allow for extended treatment with doxorubicin, but is associated with a low cardiac risk. The present study aimed to assess the response rate, survival and cardiac risk of patients with relapsed aggressive NHL treated with liposomal encapsulated doxorubicin. Eighteen patients with relapsed aggressive NHL were treated with liposomal encapsulated doxorubicin (40 - 50 mg/m2) for a planned six cycles. Some 83% of patients had diffuse large B-cell or mantle cell NHL. Four patients had a partial response (23%), whereas five patients had stable disease. None had a complete response. Eight patients progressed when receiving the liposomal encapsulated doxorubicin therapy. The median survival time was 34 weeks, and the median progression-free survival was 15.7 weeks. Overall survival was 50% at 6 months and 39% at 12 months. Progression-free survival was 33% at 6 months and was 28% at 12 months. The mean ejection fraction pre- and post-liposomal encapsulated doxorubicin treatment remained the same. Only one patient had a drop in ejection fraction to <50%. Liposomal encapsulated doxorubicin offers another choice to patients seeking palliation from their lymphoma recurrence with a response rate of 23% that was well tolerated and had a minimal cardiotoxic risk.

Enzyme immunoassay of testosterone, 17beta-estradiol, and progesterone in perspiration and urine of preadolescents and young adults: exceptional levels in men's axillary perspiration

Enzyme immunoassays for testosterone, 17beta-estradiol, and progesterone were validated for human facial and axillary perspiration and compared to levels in urine. In study 1, these assays were applied to samples from preadolescent girls and boys and young women and men. Men's axillary perspiration contained substantially higher levels of steroids than seen in other substrates from men or in any sample from women, boys, and girls. Male axillary steroid levels were very variable across individuals, and on average they exceeded levels in facial perspiration by 90-fold for testosterone and 45-fold for estradiol. Men's urinary testosterone also exceeded urinary levels of the other subjects. In study 2, axillary perspiration, urine, and saliva were collected from young men. Substantial axillary levels of testosterone and estradiol were again observed. Correlations of the same hormone among the different substrates were generally very low, except for a small correlation between estradiol levels measured in axillary perspiration and urine in study 2. High unconjugated steroid content in men's axillary excretions could, if absorbed by women during intimacy, be implicated in pheromonal activity.

In vitro function of buffy coat-derived platelet concentrates stored for 9 days in CompoSol, PASII or 100% plasma in three different storage bags

BACKGROUND AND OBJECTIVES

The aim of the study was to compare the in vitro quality of buffy coat-derived platelet concentrates (PC) during extended storage in plasma or additive solution in three different storage bags.

MATERIALS AND METHODS

A pooled and split design was chosen so that identical PCs were produced in either 100% plasma, 70% PASII : 30% plasma or 70% CompoSol : 30% plasma (n = 6 each). This was repeated for three different manufacturers' platelet storage bags (Fresenius, Baxter and Pall). PCs were sampled on days 1, 5, 7 and 9 of storage and tested in vitro using a variety of tests of platelet function. For each bag type, storage in PASII or Composol was compared with plasma (data taken across the entire storage period), and differences occurring with time were analysed for all storage media.

RESULTS

The pH of all PCs was > 6.8 at day 9 of storage. In vitro platelet function, as assessed by markers of platelet activation and metabolism, of PCs stored in CompoSol appeared to be similar to that of PCs stored in plasma over 9 days of storage. In contrast, PCs stored in PASII tended to have significantly higher levels of platelet activation (almost a twofold increase in % platelets positive for CD62P by day 5) and lower hypotonic shock response (approximately 40%, by day 7) compared to either PCs stored in 100% plasma or 70% CompoSol. The magnitude of the differences observed between platelet storage media appeared to be dependent on the type of platelet storage bag with the highest degree of platelet activation and lowest hypotonic shock response values being observed in Fresenius bags in combination with PASII.

CONCLUSIONS

The maintenance of platelet function in vitro during extended storage of PCs in platelet additive solutions is dependent on the combination of type of additive solution and type of platelet storage bag. For all bag types studied, storage in PASII resulted in poorer platelet function in vitro.

Alemtuzumab in clinical practice: A British Columbia experience

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Background: Limited information is available on alemtuzumab in the non-clinical trial setting. We evaluated its efficacy and safety in 42 consecutive unselected patients who received alemtuzumab monotherapy in British Columbia between October 2002 and August 2006. Methods: Information on patient demographics, baseline clinical and pathologic characteristics, dose and schedule of treatment, clinical response, survival, and toxicities associated with alemtuzumab were collected retrospectively. Results: Thirty-nine of 42 patients had chronic lymphocytic leukemia, 2 had mycosis fungoides, and 1 had T-cell post-transplant lymphoproliferative disorder. In contrast to previous reports, 42% were treated by community practitioners and 83% received alemtuzumab subcutaneously. The median time from diagnosis to alemtuzumab was 58 months, with a median age of 63 years at alemtuzumab treatment. Patients received a median of 4 treatments prior to starting alemtuzumab. One of 42 patients (2%) achieved a complete response, 20 (48%) achieved a partial response, 13 (31%) had stable disease, and 4 (10%) had progressive disease. The median post-alemtuzumab overall survival was 15.1 months and the median progression-free survival was 5.4 months. Response to alemtuzumab correlated with an increased progression- free survival (11 months versus 3.6 months, p=0.001) and time to next treatment (15.7 months versus 5.4 months, p=0.004). Significant adverse events included grade 3 or 4 neutropenia (75%) or thrombocytopenia (42%), infections (54%) including CMV reactivation (6%), and death (12%). Patients who received alemtuzumab in the community setting had a higher incidence of febrile neutropenia (p=0.05) and infection (p=0.03) compared to academic centres, although no difference in overall survival was noted. Conclusion: Alemtuzumab can be safely administered in a wide variety of clinical settings, including community practice, and is associated with a high level of activity.

No significant financial relationships to disclose.

Validation of candidate bovine reference genes for use with real-time PCR

Accurate quantification with real-time PCR requires the use of stable endogenous controls. Recently, there has been much debate concerning the stability of commonly used reference or housekeeping genes. To address this concern, a number of statistical approaches have been designed to analyse data and assist in determining the most appropriate reference genes for experimental comparisons. In this study, three programs, BestKeeper, Norm Finder, and geNorm were used to assess four candidate reference genes: 18S rRNA, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), acidic ribosomal protein large (RPLP0) and beta-actin, for use in expression profiling of individuals from divergent cattle genotypes subject to parasitic challenge with the cattle tick Boophilus microplus. Results demonstrated beta-actin and GAPDH were the most suitable reference genes in blood and could be used either individually or combined as an index to normalise data. RPLP0 was identified as the least stable gene, while 18S rRNA was omitted as being too highly expressed. As the recommendations on the most suitable reference genes varied between the programs, it is recommended that more than one should be utilised, to ensure the most robust experimental tools are selected.

A simple spectrophotometric method for the quantification of residual haemoglobin in platelet concentrates

BACKGROUND AND OBJECTIVES

High levels of residual haemoglobin (Hb 0.1 g/l) are known to decrease the efficiency of pathogen-inactivation systems. We evaluated three separate methods to quantify Hb in platelet concentrates (PC).

MATERIALS AND METHODS

Nine PC prepared in platelet additive solution (PASIII) (median platelet yield of 283 x 10(9)/unit, range 46-353) were spiked to known Hb concentrations with whole blood and the samples were measured by using each of three methods: the 3,3',5,5'-tetramethylbenzidine (TMB) oxidation method (Sigma Diagnostics, 527-A); the Harboe spectrophotometric method; and the HemoCue plasma low-Hb photometer (PLHP).

RESULTS

The TMB and Harboe methods showed linear results compared to expected Hb (r2 > or = 0.981, P < 0.001) over the range tested (0.09-0.28 g/l) when the samples were haemolysed. The TMB method underestimated by an average of 6%, at and around 0.1 g/l Hb, compared to a 4% overestimation by the Harboe method and a threefold overestimation by the PLHP. The Harboe intra-assay coefficient of variation was < or = 1.85% across all concentrations, which contrasted with 30% at and around 0.1 g/l for the TMB method.

CONCLUSIONS

The Harboe spectrophotometric method is convenient, safe, accurate and reproducible, and outperforms the TMB and PLHP methods for quantification of residual Hb in PC.

In vitro function of platelet concentrates prepared after filtration of whole blood or buffy coat pools

BACKGROUND/METHOD

Data on the quality of platelet concentrates (PC) produced by the buffy coat method and stored beyond 5 days in plasma are limited. We therefore evaluated the quality of PCs prepared by leucocyte depletion of whole blood (Terumo WBSP, n = 10) or a buffy coat pool (Pall Autostop, n = 10), and stored for 7 days in plasma by assessing platelet parameters and markers of platelet activation.

RESULTS

In both types of PC, levels of glucose decreased during storage but were not totally depleted (> 11 mM on day 7). In contrast, lactate levels increased on storage and was consistently < 20 mM throughout, with pH maintained at > 6.8 in all units. Hypotonic shock response scores were > 47% in all units at day 7. On day 1, markers of platelet activation were significantly higher in WBSP PC, but by day 7 were similar for percentage CD63+ and CD62P + (40%) with levels of platelet microparticles and annexin V binding two-fold higher in WBSP. The expression of CD61 did not alter during storage and the percentage of platelets expressing CD42b was > 88% in all units on day 7. RANTES (Regulated on activation, normal, T-cell expressed and secreted) and TGFbeta released from platelets by day 7 was < 800 ng/ml and 90 ng/ml, respectively. C3a(desarg) increased throughout storage in both types of PC, but without a commensurate increase in the terminal complex SC5b-9 or activation of factor XII.

CONCLUSION

Our data indicates that the in vitro characteristics of PCs prepared using these methods is maintained over storage for 7 days in plasma and is not associated with significant deterioration of platelet function. ONE SENTENCE SUMMARY: In vitro function of platelet concentrates prepared by either filtration of whole blood, or pooled buffy coats.

Treatment of MTBE by air stripping, carbon adsorption, and advanced oxidation: technical and economic comparison for five groundwaters

An investigation was made of the treatability of methyl tert-butyl ether (MTBE) in five groundwaters with highly varied water quality characteristics. Air stripping, granular activated carbon (GAC) adsorption, and the O(3)/H(2)O(2) and UV/H(2)O(2) advanced oxidation processes were compared in a mobile water treatment pilot plant under a variety of process conditions. Air stripping was shown to have the lower unit treatment costs for higher flowrates (i.e., 3800L/min), although relatively tall towers were required for greater treatment requirements. At low flowrates (i.e., 38L/min), advanced oxidation provided the lowest treatment costs for four of five waters (but was ineffective for a high chemical oxygen demand water). Both the O(3)/H(2)O(2) and UV/H(2)O(2) processes were more efficient at pH 7 versus 9 due in part to increased scavenging at higher pH. GAC was examined using rapid small-scale column tests (RSSCT). GAC was effective at most conditions, although it was also the most costly alternative for most waters. The results of this study can help to provide specific guidance into process selection for treating MTBE in contaminated groundwaters.

Expression of a plant-derived peptide harboring water-cleaning and antimicrobial activities

Drinking water is currently a scarce world resource, the preparation of which requires complex treatments that include clarification of suspended particles and disinfection. Seed extracts of Moringa oleifera Lam., a tropical tree, have been proposed as an environment-friendly alternative, due to their traditional use for the clarification of drinking water. However, the precise nature of the active components of the extract and whether they may be produced in recombinant form are unknown. Here we show that recombinant or synthetic forms of a cationic seed polypeptide mediate efficient sedimentation of suspended mineral particles and bacteria. Unexpectedly, the polypeptide was also found to possesses a bactericidal activity capable of disinfecting heavily contaminated water. Furthermore, the polypeptide has been shown to efficiently kill several pathogenic bacteria, including antibiotic-resistant isolates of Staphylococcus, Streptococcus, and Legionella species. Thus, this polypeptide displays the unprecedented feature of combining water purification and disinfectant properties. Identification of an active principle derived from the seed extracts points to a range of potential for drinking water treatment or skin and mucosal disinfection in clinical settings.

The influence of platelet additive solutions on cytokine levels and complement activation in platelet concentrates during storage

BACKGROUND AND OBJECTIVES

The accumulation of platelet-derived cytokines in platelet concentrates (PC) during storage may contribute towards non-haemolytic transfusion reactions (NHTR). We investigated the effect of platelet storage medium on platelet activation, complement activation and cytokine levels in leucocyte-reduced PC.

MATERIALS AND METHODS

Hyperconcentrated platelets (3000-6000 x 109/l) were collected by apheresis and diluted in 100% plasma, 70% PASIII, or 70% or 80% PASIII supplemented with magnesium and potassium (PAS IIIM).

RESULTS

Levels of transforming growth factor-beta (TGF-beta) and regulated on activation, normal, T-cell expressed, and secreted (RANTES) increased during storage, as did the expression of P-selectin (CD62P), and were highest in PC stored in PASIII. In PC stored in PASIIIM, however, levels of TGF-beta and RANTES were not significantly different from PC stored in plasma. Levels of CD62P expression, however, remained higher in PASIIIM PC than in those stored in plasma by day 5, but were lower than PC stored in PASIII. C3a des arg levels increased during storage in all media with the exception of PASIII and, on day 7, were higher in PC stored in plasma compared to PC stored in the other media.

CONCLUSIONS

Our results indicate that replacing plasma in PC with unmodified PASIII for storage results in higher levels of platelet-derived cytokines in PC. Furthermore, it appears that the nature of the medium used for storage of PC has a significant impact on platelet activation and cytokine levels of the PC. These implications should be taken into account when considering replacement of plasma with PAS.

Clustered DNA damages induced by high and low LET radiation, including heavy ions

Clustered DNA damages--here defined as two or more lesions (strand breaks, oxidized purines, oxidized pyrimidines or abasic sites) within a few helical turns--have been postulated as difficult to repair accurately, and thus highly significant biological lesions. Further, attempted repair of clusters may produce double strand breaks (DSBs). However, until recently, there was no way to measure ionizing radiation-induced clustered damages, except DSB. We recently described an approach for measuring classes of clustered damages (oxidized purine clusters, oxidized pyrimidine clusters, abasic clusters, along with DSB). We showed that ionizing radiation (gamma rays and Fe ions, 1 GeV/amu) does induce such clusters in genomic DNA in solution and in human cells. These studies also showed that each damage cluster results from one radiation hit (and its track), thus indicating that they can be induced by very low doses of radiation, i.e. two independent hits are not required for cluster induction. Further, among all complex damages, double strand breaks comprise--at most-- ~20%, with the other clustered damages being at least 80%.

Molecular mechanisms of nickel carcinogenesis

Humans are exposed to carcinogenic nickel (Ni) compounds both occupationally and environmentally. In this paper, molecular mechanisms of nickel carcinogenesis are considered from the point-of-view of the uptake of nickel sulfide particles in cells, their dissolution and their effects on heterochromatin. Molecular mechanisms by which nickel induces gene silencing, DNA hypermethylation and inhibition of histone acetylation, will be discussed.

Residual subset population analysis in WBC-reduced blood components using real-time PCR quantitation of specific mRNA

BACKGROUND

Implementation of WBC reduction of the blood supply increases the importance of measurement of residual WBC subtypes responsible for immunologic and infectious complications of transfusion.

STUDY DESIGN AND METHODS

Real-time RT-PCR assays were developed to detect mRNA encoding lineage-specific WBC markers. Primers and fluorescent probes were designed for CD45 (pan-WBC), CD3 (T-lymphocyte), CD19 (B-lymphocyte), CD14 (monocyte), and CD66 (granulocyte), and the specificity was assessed by comparison with flow cytometric analysis of enriched cell populations. WBC subsets were examined in WBC-reduced whole blood prepared with filters (WBF2, Pall; and RZ2000, Baxter) and in platelet concentrates prepared with other filters (Autostop, Pall; and PLX-5, Baxter) and apheresis (COBE Spectra LRS, Gambro).

RESULTS

All real-time RT-PCR assays were linear over >5 log concentration range, allowing pre-WBC-reduction and post-WBC-reduction comparisons. Sensitivity limits ranged from 10 cells per mL (CD45) to 200 cells per mL (CD19). Assay specificity was confirmed by the close correlation of real-time RT-PCR and immunophenotyping results by flow cytometry. For all subsets, >3.8 log and >3.1 log reduction was obtained during WBC reduction of whole blood and platelets, respectively.

CONCLUSION

Real-time RT-PCR assays are suitable for analysis of subset removal during WBC reduction. There was no significant difference between the two whole-blood filters or between platelet filtration and apheresis in the removal of any WBC subset.

The effect of leucocyte depletion on the quality of fresh-frozen plasma

The aim of this study was to evaluate the quality of leucodepleted (LD) fresh-frozen plasma (FFP) produced using one of five whole blood filters (Baxter RS2000 & RZ2000, NPBI T2926, Macopharma LST1 and Terumo WBSP) or two plasma filters (Pall LPS1 and Baxter FGR7014). Whole blood or plasma was filtered within 8 h of collection at an ambient temperature. Samples were taken pre- and post filtration for analysis of coagulation factors and complement activation (n = 7--12 for each type of filter). All filtered units (209--286 ml) contained < 5 x 10(6) residual leucocytes and < 30 x 10(9)/l platelets. Statistically significant losses of factors V, VIII, IX, XI and XII and increases in markers of coagulation activation were observed (0--21%), which were dependent on filter type. None of the filters had a significant effect on von Willebrand factor (VWF) multimeric distribution or the activity of VWF and factors II, VII or X. The effect on levels of C3a appeared to be related to the filter surface charge: positively charged filters resulted in C3a generation, whereas negatively charged resulted in C3a removal. None of the observed changes are likely to be clinically significant unless subsequent processing of plasma (such as pathogen inactivation) results in further losses of coagulation factors.