Comparison of cord blood thawing methods on cell recovery, potency, and infusion

BACKGROUND: Umbilical cord blood (UCB) products have traditionally been thawed using a washing method intended to stabilize the cells, reduce dimethyl sulfoxide (DMSO) toxicity, and remove potentially ABO‐incompatible red blood cell (RBC) stroma and plasma. Concerns with this approach include loss of total nucleated cells (TNCs), bag breakage during centrifugation, and poor reproducibility by transplant centers unfamiliar with this technique. We rationalized that a simple 1:1 dilution without centrifugation would stabilize the product and reduce the DMSO concentration by 50%, allowing for a controlled thaw in the laboratory without the risks of cell loss. STUDY DESIGN AND METHODS: We compared the traditional wash method with albumin reconstitution (dilution) and thaw only (no dilution or wash), assessing measurements of viability, TNC, CD34, and colony‐forming cell (CFC) recovery post‐thaw. Ten cryopreserved UCB products were thawed, split equally into three parts, and treated using each method. Product stability was measured at multiple time intervals up to 48 hours post‐thaw. RESULTS: Throughout the entire evaluation, traditional wash and dilution methods performed equally well with no significant differences observed in 7‐aminoactinomycin viability, TNC, CD34, or CFC recovery. For 163 patients in which diluted products were administered, there were no serious adverse effects at infusion and similar time to engraftment was observed when compared to historical experiences with traditional wash and direct infusion. CONCLUSION: We conclude that removing DMSO, RBC stroma, and plasma post‐thaw using a wash method is not necessary when UCB products are RBC and plasma reduced before cryopreservation.     

Ionizing radiation exposure as a result of diagnostic imaging in patients with lymphoma

Purpose

Survival rates among patients with lymphoma continue to improve. Strategies aimed at reducing potential treatment-related toxicity are increasingly prioritized. While radiological procedures play an important role, ionizing radiation exposure has been linked to an increased risk of malignancy, particularly among individuals whose cumulative radiation exposure exceeds a specific threshold (75 millisieverts).

Methods

Within this retrospective study, the cumulative radiation exposure dose was quantified for 486 consecutive patients with lymphoma.

Results

The median estimated total cumulative effective dose (CED) of ionizing radiation per subject was 69 mSv (42–118). However, younger patients (under 40 years) had a median CED of 89 mSv (55–124).

Conclusion

This study highlights the considerable radiation exposure occurring among patients with lymphoma as a result of diagnostic imaging. To limit the risk of secondary carcinogenesis, consideration should be given to monitoring cumulative radiation exposure in individual patients as well as considering imaging modalities, which do not impart an ionizing radiation dose.

     

Factor V Leiden and recurrent miscarriage-prospective outcome of untreated pregnancies

BACKGROUND: Some cases of recurrent miscarriage and later pregnancy complications have a thrombotic basis. Factor V Leiden is a common thrombophilic mutation. METHODS: The prospective outcome of untreated pregnancies amongst 25 women heterozygous for the Factor V Leiden allele who had a history of either recurrent early miscarriages only (three or more miscarriages at <12 weeks gestation; n = 19) or of late miscarriage (>12 weeks gestation; n = 9) was studied. Control groups of women with a similar pregnancy history but who had a normal Factor V genotype were also studied. RESULTS: The live birth rate was significantly lower amongst women with a history of recurrent early miscarriage who carried the Factor V Leiden allele (6/16; 37.5%) compared with that amongst those with a normal Factor V genotype (106/153; 69.3%; odds ratio 3.75, 95% confidence intervals 1.3-10.9). The live birth rate was 11.1% (1/9) amongst those with a history of late miscarriage carrying the Factor V Leiden allele and 48.9% (22/45) amongst those with a normal Factor V genotype. CONCLUSIONS: Attention should be directed at screening women with recurrent miscarriage associated with placental thrombosis for Factor V Leiden and a policy of targeted thromboprophylaxis during future pregnancies should be assessed in the form of a randomized controlled trial.     

The application of antibody coated polyacrylamide gel (immunobead) in the NBT test for the detection of ingestion and killing functions of human neutrophils.

An improved assay for the simultaneous assessment of phagocytic uptake (via immunobeads) and metabolic integrity (via NBT dye reduction) in neutrophils is described. Normal human neutrophils exhibited ingestion and dye reduction, whereas neutrophils from newborn cord blood showed ingestion with slight reduction and neutrophils from patients with chronic granulomatous disease displayed hyper-ingestion and no subsequent dye reduction.     

Functional nanoscale organization of signaling molecules downstream of the T cell antigen receptor

Receptor-regulated cellular signaling often is mediated by formation of transient, heterogeneous protein complexes of undefined structure. We used single and two-color photoactivated localization microscopy to study complexes downstream of the T cell antigen receptor (TCR) in single-molecule detail at the plasma membrane of intact T cells. The kinase ZAP-70 distributed completely with the TCRζ chain and both partially mixed with the adaptor LAT in activated cells, thus showing localized activation of LAT by TCR-coupled ZAP-70. In resting and activated cells, LAT primarily resided in nanoscale clusters as small as dimers whose formation depended on protein-protein and protein-lipid interactions. Surprisingly, the adaptor SLP-76 localized to the periphery of LAT clusters. This nanoscale structure depended on polymerized actin and its disruption affected TCR-dependent cell function. These results extend our understanding of the mechanism of T cell activation and the formation and organization of TCR-mediated signaling complexes, findings also relevant to other receptor systems.     

Identification of non-recurrent submicroscopic genome imbalances: the advantage of genome-wide microarrays over targeted approaches

Genome-wide analysis of DNA copy-number changes using microarray-based technologies has enabled the detection of de novo cryptic chromosome imbalances in approximately 10% of individuals with mental retardation. So far, the majority of these submicroscopic microdeletions/duplications appear to be unique, hampering clinical interpretation and genetic counselling. We hypothesised that the genomic regions involved in these de novo submicroscopic aberrations would be candidates for recurrent copy-number changes in individuals with mental retardation. To test this hypothesis, we used multiplex ligation-dependent probe amplification (MLPA) to screen for copy number changes at eight genomic candidate regions in a European cohort of 710 individuals with idiopathic mental retardation. By doing so, we failed to detect additional submicroscopic rearrangements, indicating that the anomalies tested are non-recurrent in this cohort of patients. The break points flanking the candidate regions did not contain low copy repeats and/or sequence similarities, thus providing an explanation for its non-recurrent nature. On the basis of these data, we propose that the use of genome-wide microarrays is indicated when testing for copy-number changes in individuals with idiopathic mental retardation.     

Giant leiomyoma of the prostate

Giant leiomyoma of the prostate is a rare lesion. We document a case in a 61-year-old man who presented with urinary obstructive symptoms. He had undergone transurethral resection twice before he was seen at our institution, where suprapubic prostatectomy was performed. At follow-up 18 months postoperatively, no evidence of recurrent disease was found and his voiding pattern was normal.