Persistent aggregates in apheresis platelet concentrates are commonly collected from donors with a history of aggregate donation

Platelet apheresis sometimes causes persistent aggregates (PA). This study (n = 211) shows that changing the apheresis settings to reach fixed product volumes instead of yields does not influence PA incidence, even though PA products on average contain more platelets than controls. Furthermore, logistic regression was used to model if PA can be predicted on the basis of certain predonation parameters. PA donation history was the only parameter retained, proving a strong determinant of predictability [AUC = 0.735 (SE = 0.022)]. Consequently, donations from a donor with previous PA history are 7.8 times more likely to contain PA than from a donor without preceding history

Is sexual risk behaviour associated with an increased risk of transfusion-transmissible infections in blood donors from Western and Pacific countries? A systematic review and meta-analysis

Background and Objectives The donor medical questionnaire is designed to aid blood establishments in supporting a safe blood supply. According to blood donor deferral policies, sexual risk behaviour (SRB) leads to a (temporary) deferral from blood donation. This systematic review aimed to scientifically underpin these policies by identifying the best available evidence on the association between SRB and the risk of transfusion transmissible infections (TTIs). Materials & Methods Studies from three databases investigating the link between SRB (excluding men who have sex with men (MSM)) and TTIs (HBV, HCV, HIV, Treponema pallidum) in donors from Western and Pacific countries were obtained and assessed on eligibility by two reviewers independently. The association between SRB and TTIs was expressed by calculating pooled effect measures via meta-analyses. The GRADE methodology (Grades of Recommendation, Assessment, Development and Evaluation) was used to assess the quality of evidence. Results We identified 3750 references and finally included 15 observational studies. Meta-analyses showed that there is a significant (P < 0 center dot 05) positive association between the following SRB and HBV and/or HCV infection: having sex with an intravenous drug user (high-certainty evidence), receiving money or goods for sex (moderate-high certainty evidence), having a sex partner with hepatitis/HIV (moderate-certainty evidence) and paid for sex or anal sex (low-certainty evidence). Conclusion Sexual risk behaviour (including having sex with an intravenous drug user, receiving money or goods for sex or having a sex partner with hepatitis/HIV) is probably associated with an increased risk of HBV/HCV infection in blood donors from Western and Pacific countries

CHARACTERIZATION OF F107 FIMBRIAE OF ESCHERICHIA-COLI 107/86, WHICH CAUSES EDEMA DISEASE IN PIGS, AND NUCLEOTIDE-SEQUENCE OF THE F107 MAJOR FIMBRIAL SUBUNIT GENE, FEDA

F107 fimbriae were isolated and purified from edema disease strain 107/86 of Escherichia coli. Plasmid pIH120 was constructed, which contains the gene cluster that codes for adhesive F107 fimbriae. The major fimbrial subunit gene, fedA, was sequenced. An open reading frame that codes for a protein with 170 amino acids, including a 21-amino-acid signal peptide, was found. The protein without the signal sequence has a calculated molecular mass of 15,099 Da. Construction of a nonsense mutation in the open reading frame of fedA abolished both fimbrial expression and the capacity to adhere to isolated porcine intestinal villi. In a screening of 28 reference edema disease strains and isolates from clinically ill piglets, fedA was detected in 24 cases (85.7%). In 20 (83.3%) of these 24 strains, fedA was found in association with Shiga-like toxin II variant genes, coding for the toxin that is characteristic for edema disease strains of E. coli. The fimbrial subunit gene was not detected in enterotoxigenic E. coli strains. Because of the capacity of E. coli HB101(pIH120) transformants to adhere to isolated porcine intestinal villi, the high prevalence of fedA in edema disease strains, and the high correlation with the Shiga-like toxin II variant toxin-encoding genes, we suggest that F107 fimbriae are an important virulence factor in edema disease strains of E. coli

Single cell epigenetic visualization assay

Abstract Characterization of the epigenetic status of individual cells remains a challenge. Current sequencing approaches have limited coverage, and it is difficult to assign an epigenetic status to the transcription state of individual gene alleles in the same cell. To address these limitations, a targeted microscopy-based epigenetic visualization assay (EVA) was developed for detection and quantification of epigenetic marks at genes of interest in single cells. The assay is based on an in situ biochemical reaction between an antibody-conjugated alkaline phosphatase bound to the epigenetic mark of interest, and a 5′-phosphorylated fluorophore-labeled DNA oligo tethered to a target gene by gene-specific oligonucleotides. When the epigenetic mark is present at the gene, phosphate group removal by the phosphatase protects the oligo from λ-exonuclease activity providing a quantitative fluorescent readout. We applied EVA to measure 5-methylcytosine (5mC) and H3K9Ac levels at different genes and the HIV-1 provirus in human cell lines. To link epigenetic marks to gene transcription, EVA was combined with RNA-FISH. Higher 5mC levels at the silenced compared to transcribed XIST gene alleles in female somatic cells validated this approach and demonstrated that EVA can be used to relate epigenetic marks to the transcription status of individual gene alleles.</jats:p

Long non-coding RNAs and latent HIV : a search for novel targets for latency reversal

The latent cellular reservoir of HIV is recognized as the major barrier to cure from HIV infection. Long non-coding RNAs (lncRNAs) are more tissue and cell type-specific than protein coding genes, and may represent targets of choice for HIV latency reversal. Using two in vitro primary T-cell models, we identified lncRNAs dysregulated in latency. PVT1 and RP11-347C18.3 were up-regulated in common between the two models, and RP11-539L10.2 was down-regulated. The major component of the latent HIV reservoir, memory CD4+ T-cells, had higher expression of these lncRNAs, compared to naive T-cells. Guilt-by-association analysis demonstrated that lncRNAs dysregulated in latency were associated with several cellular pathways implicated in HIV latency establishment and maintenance: proteasome, spliceosome, p53 signaling, and mammalian target of rapamycin (MTOR). PVT1, RP11-347C18.3, and RP11-539L10.2 were down-regulated by latency reversing agents, suberoylanilide hydroxamic acid and Romidepsin, suggesting that modulation of lncRNAs is a possible secondary mechanism of action of these compounds. These results will facilitate prioritization of lncRNAs for evaluation as targets for HIV latency reversal. Importantly, our study provides insights into regulatory function of lncRNA during latent HIV infection

Sequence, expression and mutational analysis of BAF1, a transcriptional activator and ARS1-binding protein of the yeast Saccharomyces cerevisiae.

We report the cloning and sequence analysis of the yeast BAF1 gene which encodes an abundant protein previously shown to act as a transcription activator in the YPT1-TUB2 intergene region. As predicted from the DNA sequence, the highly hydrophilic BAf1 protein is 731 amino acids long and has a molecular mass of 81 748 daltons. The protein product of the cloned BAF1 gene produced in Escherichia coli is able to form specific complexes with DNA fragments containing the conserved element TCN7ACG. The protein binds also to the ABF1-binding site of the B-domain of ARS1, entertaining the possibility that BAF1 and ABF1 are identical proteins. Extensive deletion studies identified the N-terminal two thirds of the Baf1 protein to be required for specific DNA binding. Amino acid substitutions point to the N-terminal sequence CysX7HisX3HisX4CysX4Cys to form an atypical metal-binding 'finger' structure. Disruption of the BAF1 gene is lethal. The existence of five potential Baf1-protein binding sites in the 5' region of the gene suggests the involvement of the Baf1 protein in transcription regulation of its own gene

Extraordinary claims, extraordinary evidence? A discussion

Roberts (2020, Learning & Behavior, 48[2], 191-192) discussed research claiming honeybees can do arithmetic. Some readers of this research might regard such claims as unlikely. The present authors used this example as a basis for a debate on the criterion that ought to be used for publication of results or conclusions that could be viewed as unlikely by a significant number of readers, editors, or reviewers.Peer reviewe

Impact of the HIV-1 genetic background and HIV-1 population size on the evolution of raltegravir resistance

Background: Emergence of resistance against integrase inhibitor raltegravir in human immunodeficiency virus type 1 (HIV-1) patients is generally associated with selection of one of three signature mutations: Y143C/R, Q148K/H/R or N155H, representing three distinct resistance pathways. The mechanisms that drive selection of a specific pathway are still poorly understood. We investigated the impact of the HIV-1 genetic background and population dynamics on the emergence of raltegravir resistance. Using deep sequencing we analyzed the integrase coding sequence (CDS) in longitudinal samples from five patients who initiated raltegravir plus optimized background therapy at viral loads > 5000 copies/ml. To investigate the role of the HIV-1 genetic background we created recombinant viruses containing the viral integrase coding region from pre-raltegravir samples from two patients in whom raltegravir resistance developed through different pathways. The in vitro selections performed with these recombinant viruses were designed to mimic natural population bottlenecks. Results: Deep sequencing analysis of the viral integrase CDS revealed that the virological response to raltegravir containing therapy inversely correlated with the relative amount of unique sequence variants that emerged suggesting diversifying selection during drug pressure. In 4/5 patients multiple signature mutations representing different resistance pathways were observed. Interestingly, the resistant population can consist of a single resistant variant that completely dominates the population but also of multiple variants from different resistance pathways that coexist in the viral population. We also found evidence for increased diversification after stronger bottlenecks. In vitro selections with low viral titers, mimicking population bottlenecks, revealed that both recombinant viruses and HXB2 reference virus were able to select mutations from different resistance pathways, although typically only one resistance pathway emerged in each individual culture. Conclusions: The generation of a specific raltegravir resistant variant is not predisposed in the genetic background of the viral integrase CDS. Typically, in the early phases of therapy failure the sequence space is explored and multiple resistance pathways emerge and then compete for dominance which frequently results in a switch of the dominant population over time towards the fittest variant or even multiple variants of similar fitness that can coexist in the viral population