Michal Tarnawski

Detection of blood group genes using multiplex SNaPshot method

BACKGROUND: The determination of blood group antigens in patients and donors is of primary importance in transfusion medicine. Blood group antigens are inherited and are polymorphic in nature. The majority of polymorphic blood group antigens arise from single‐nucleotide polymorphisms (SNPs) in the blood group genes. Many DNA‐based assays, such as species‐specific polymerase chain reaction (PCR), PCR–restriction fragment length polymorphism, and microchips, have been described to study variant blood group genes. In this study, the SNaPshot (Applied Biosystems) method was adapted to detect SNPs in 10 common blood group systems.

Immunogold study of altered expression of some interendothelial junctional molecules in the brain blood microvessels of diabetic scrapie-infected mice

Quantitative immunogold procedure was used to study the distribution of molecular components of interendothelial junctions in blood–brain barrier (BBB) microvessels of scrapie infected SJL/J hyperglycemic mice showing obesity and reduced glucose tolerance. Samples of brain (fronto-parietal cerebral cortex and thalamo-hypothalamic region) obtained from hyperglycemic (diabetic) mice and from non- infected, normoglycemic (non-diabetic) SJL/J mice, were processed for immunocytochemical examination. The localization of the following tight junction (TJ)-associated proteins was studied: occludin as an integral membrane (transmembrane) protein, and zonula occludens one (ZO-1) as a peripheral protein. The localization of β-catenin as a representative of the cadherin/catenin complex that is typical for adherens junctions (AJs) also was studied. Morphometric analysis revealed that the density of immunosignals for occludin, represented by colloidal gold particles (GPs), was significantly lower in the brain microvessels of diabetic than in non-diabetic mice. No significant differences in the density of immunosignals for ZO-1 and β-catenin between both experimental mouse groups were observed. It indicates that abnormal glucose metabolism affects mostly occludin which is believed to play a fundamental role in the maintenance of the tightness of endothelial lining in brain microvascular network and thereby in the preservation of its barrier function. These results also support the previously expressed opinion that occludin, detected with the applied morphological method, can be considered a sensitive indicator of altered molecular architecture of the interendothelial junctions due to the action of some metabolic or pathological insults.

Impact of delayed umbilical cord clamping on public cord blood donations: can we help future patients and benefit infant donors?

Cord blood (CB) is a widely accepted stem cell source and its clinical utilization depends, to a great extent, on its cell content. Birth‐to‐clamping (BTC) time of umbilical cord determines placental transfusion to the newborn, and the remaining blood that can be collected and banked. The 2017 Committee Opinion of the American College of Obstetrics and Gynecologists (ACOG) recommends a delay of “at least 30‐60 seconds” before clamping the cord for all newborns to ensure adequate iron stores. The impact of delayed cord clamping (DCC) on public CB banking can be substantial.

Cytomegalovirus viral load in cord blood and impact of congenital infection on markers of hematopoietic progenitor cell potency

The low incidence of cytomegalovirus (CMV) infection in neonates decreases the risk of viral transmission with cord blood transplantation. Cord blood donors are screened by testing the maternal sample for total antibodies to CMV. Some cord blood banks also screen cord blood for CMV‐DNA. The aim of this study was to develop and validate a multiplex real‐time polymerase chain reaction assay to measure CMV viral load in cord blood from asymptomatic infants with congenital CMV infection and to assess the impact of CMV infection on cord blood hematopoietic progenitor cell concentrations and colony‐forming unit functionality.