Effect of freezing on the in vivo recovery of irradiated red cells

BACKGROUND: Transfusion-associated graft-versus-host disease can be prevented by gamma radiation of blood components. The increased use of blood components donated for patients by their family members has resulted in an increased demand for the storage and handling of irradiated units, and the ability to freeze the cells would allow storage beyond their current expiration date. STUDY DESIGN AND METHODS: To assess the effect of freezing and deglycerolization on irradiated red cells, studies of autologous radiolabeled red cell recovery were performed using normal volunteers. Each unit of CPDA-1 red cells was immediately divided into two equal volumes. Further handling of each half was identical except that one was irradiated (3500 cGy). The units were grouped under three protocols: I, irradiated on Day 0 and frozen on Day 5 (n = 4); II, irradiated on Day 7, rejuvenated, and frozen on Day 14 (n = 5); and III, irradiated on Day 14, rejuvenated, and frozen on Day 18 (n = 3). All cells were frozen for 3 to 10 months at -80 degrees C. RESULTS: Irradiated and control units showed no significant differences in supernatant potassium or hemoglobin. Autologous 24-hour posttransfusion recoveries (mean +/− SD) for the three groups were: I, 89.7 +/− 5.6 percent (control, 90.6 +/− 3.2%); II, 85.3 +/− 5.7 percent (control, 83.7 +/− 3.0%); and III, 79.5 +/− 1.4 percent (control, 82.6 +/− 5.2%). CONCLUSION: Irradiated red cells can be frozen after being stored under various conditions and can still meet established guidelines requiring 75-percent recovery 24 hours after transfusion.     

The stated and tacit impact of demographic and lifestyle factors on prioritization decisions for cardiac surgery

In a clinical judgement analysis, we used linear regression models to reflect the impact of clinical and non-clinical cues on priority decisions, by comparing the stated prioritization policies of 30 clinicians with their actual policies as revealed by an appraisal of 50 'paper patients'. Correspondence was modest for some cues, e.g. 25 doctors said they accounted for age, but age only had a significant bearing in the derived decision models of two doctors. Correspondence between the derived and expressed weights was greatest for clinical angina grade and the presence of left main stem stenosis. Correlation between the rank order of importance between the two models was poor for most of the cues, and statistically significant only for smoking. However, stated policies made it appear that lifestyle factors such as smoking habit would influence prioritization decisions for most clinicians but policies derived from actual prioritization decisions seldom related to lifestyle or demographic variables. There were significant differences in the degree of correlation between the two models according to the experience of the clinician. However, correspondence was not significantly better for doctors with cardiological training than those without. The overall contribution of demographic and lifestyle factors to decision making appears to be small, suggesting that they should be omitted from prioritization guidelines.      

Determination of the solute removal index for urea by using a partial spent dialysate collection method

In 22 hemodialysis patients, during a dialysis session, the solute removal index (SRI) for urea obtained from the use of a partial spent dialysate collection method was compared with that derived from the use of a total spent dialysate collection technique. The partial spent dialysate collection method was used to harvest a small representative sample of the total spent dialysate. The volumes of spent dialysate collected by the partial and the total spent dialysate collection methods were 1.7 +/- 0.4 L and 129.6 +/- 15.3 L, respectively. The total amount of urea nitrogen removed by dialysis as estimated by the partial spent dialysate collection method was similar to that determined by the total spent dialysate collection approach. As a result, the SRI value for urea obtained by the partial spent dialysate collection method (namely, 63% +/- 8%) correlated very well (r = 0.95, P < 0.001) with that derived by the total spent dialysate collection technique (namely, 62% +/- 8%). Our data suggest that it is feasible to use a simple partial spent dialysate collection method to obtain SRI results in patients treated with hemodialysis.     

Absence of mutations in the transforming growth factor-beta type II receptor in sporadic lung cancers with microsatellite instability and rare H-ras1 alleles

The transforming growth factor-beta type II receptor (RII) is commonly mutated in colon and gastric cancers with microsatellite instability (MI). We utilized our series of lung cancers with MI and rare alleles of the H-ras1 gene to determine the association between MI and RII mutations and searched the entire RII coding region in 33 lung cancers with MI by polymerase chain reaction-single-strand conformation polymorphism analysis. We found no mutations, and these data support other recent evidence that RII mutations rarely occur except in colon and gastric tumors with MI.      

Population sub-structuring among <Emphasis Type="Italic">Trypanosoma evansi</Emphasis> stocks

To investigate the population genetic structure of Trypanosoma evansi from domesticated animals, we have analysed 112 stocks from camels, buffaloes, cattle and horses using the tandemly repeated coding sequence (MORF2) and minisatellite markers 292 and cysteine-rich acidic integral membrane protein (CRAM). We recorded a total of six alleles at the MORF2 locus, seven at 292 and 12 at the CRAM loci. Nei’s genetic distance showed reduced allelic diversity between buffaloes and cattle stocks (1.2) as compared to the diversity between camels and buffaloes (3.75) and camels and cattle stock (1.69). The mean index of association (I _A = 0.92) significantly deviated from zero, and the average number of multilocus genotypes (G/N ratio) was 0.21. Twenty-four multilocus genotypes were defined from the combination of alleles at the three loci. The Kenyan sub-populations showed F _st = 0.28 and analysis of molecular variance showed significant divergence (22.7%) between the Laikipia, Kulal and Galana regions. The regional and host distribution of multi-locus genotypes significant population differentiation and high Nei’s genetic distances suggest existence of genetic sub-structuring within T. evansi stocks while the few multi-locus genotypes and deviation of association index from zero indicate the lack of recombination. In conclusion, this study reveals that some genetic sub-structuring does occur within T. evansi, which has a clonal population structure.     

Basic newborn care and neonatal resuscitation: a multi-country analysis of health system bottlenecks and potential solutions

Background

An estimated two-thirds of the world's 2.7 million newborn deaths could be prevented with quality care at birth and during the postnatal period. Basic Newborn Care (BNC) is part of the solution and includes hygienic birth and newborn care practices including cord care, thermal care, and early and exclusive breastfeeding. Timely provision of resuscitation if needed is also critical to newborn survival. This paper describes health system barriers to BNC and neonatal resuscitation and proposes solutions to scale up evidence-based strategies.

Methods

The maternal and newborn bottleneck analysis tool was applied by 12 countries in Africa and Asia as part of the Every Newborn Action Plan process. Country workshops engaged technical experts to complete the survey tool, which is designed to synthesise and grade health system "bottlenecks" that hinder the scale up of maternal-newborn intervention packages. We used quantitative and qualitative methods to analyse the bottleneck data, combined with literature review, to present priority bottlenecks and actions relevant to different health system building blocks for BNC and neonatal resuscitation.

Results

Eleven of the 12 countries provided grading data. Overall, bottlenecks were graded more severely for resuscitation. The most severely graded bottlenecks for BNC were health workforce (8 of 11 countries), health financing (9 out of 11) and service delivery (7 out of 9); and for neonatal resuscitation, workforce (9 out of 10), essential commodities (9 out of 10) and service delivery (8 out of 10). Country teams from Africa graded bottlenecks overall more severely. Improving workforce performance, availability of essential commodities, and well-integrated health service delivery were the key solutions proposed.

Conclusions

BNC was perceived to have the least health system challenges among the seven maternal and newborn intervention packages assessed. Although neonatal resuscitation bottlenecks were graded more severe than for BNC, similarities particularly in the workforce and service delivery building blocks highlight the inextricable link between the two interventions and the need to equip birth attendants with requisite skills and commodities to assess and care for every newborn. Solutions highlighted by country teams include ensuring more investment to improve workforce performance and distribution, especially numbers of skilled birth attendants, incentives for placement in challenging settings, and skills-based training particularly for neonatal resuscitation.

     

Expansion in vitro of retrovirally marked totipotent hematopoietic stem cells

A large number of biologic, technological, and clinical studies await the development of procedures that will allow totipotent hematopoietic stem cells to be expanded in vitro. Previous work has suggested that hematopoiesis can be reconstituted using transplants of cells from long- term marrow cultures. We have used retrovirus mediated gene transfer to demonstrate that marked totipotent hematopoietic stem cells are both maintained and can be amplified in such cultures, and then subsequently regenerate and sustain lympho-myeloid hematopoiesis in irradiated recipients. Marrow cells from 5-fluorouracil-treated male mice were infected with a recombinant virus carrying the neomycin resistence gene and seeded onto irradiated adherent layers of pre-established, long- term marrow cultures of female origin. At 4 weeks, cells from individual cultures were transplanted into single or multiple female recipients. Southern blot analysis of hematopoietic tissue 45 days posttransplantation showed retrovirally marked clones common to lymphoid and myeloid tissues in 14 of 23 mice examined. Strikingly, for 3 of 4 long-term cultures, multiple recipients of cells from a single flask showed marrow and thymus repopulation with the same unique retrovirally marked clone. These results establish the feasibility of retroviral-marking techniques to demonstrate the maintenance of totipotent lympho-myeloid stem cells for at least 4 weeks in the long- term marrow culture system and provide the first evidence of their proliferation in vitro. Therefore, such cultures may serve as a starting point for identifying factors that stimulate totipotent hematopoietic stem cell expansion.