Serological testing for SARS-CoV-2 in Bosnia and Herzegovina: first report

IntroductionSerological detection of SARS-CoV-2-specific immunoglobulins G (IgG) and M (IgM) antibodies is becoming increasingly important in the management of the COVID-19 pandemic.MethodsWe report the first results of COVID-19 serological testing in Bosnia and Herzegovina on 2841 samples collected and analysed in 2 medical institutions in Sarajevo. Antibody detection was performed using commercially available kits.ResultsIn the first cohort, 43 IgM-positive/IgG-negative and 16 IgM-positive/IgG-positive individuals were detected, corresponding to 3.41% of participants having developed antibodies. In the second cohort, 4.28% participants were found to be IgM-negative/IgG-positive.ConclusionsOur results suggest the need for population-wide serological surveying in Bosnia and Herzegovina.     

Identification and molecular characterization of a marafivirus in <Emphasis Type="Italic">Rubus</Emphasis> spp.

An undescribed virus with isometric particles and a diameter of ca. 30 nm was identified in diseased samples of wild and cultivated Rubus species and molecularly characterized. Its genome was 6,463 nt, excluding the 3′-terminal poly(A) tail, and contained a single open reading frame coding for a 2,035-amino-acid-long precursor polypeptide (p223). The amino terminal portion of p223, identified as a replication-associated polyprotein, contained conserved motifs of methyltransferase, endopeptidase/protease, helicase and RNA-dependent RNA polymerase. The carboxy terminus of the large polypeptide is involved in the formation of two viral coat protein subunits with deduced molecular masses of 23 and 21 kDa. Pairwise comparisons and phylogenetic analyses showed closest relationships of this virus with oat blue dwarf virus and citrus sudden death-associated virus, sharing levels of genome sequence conservation far below the species demarcation level established for tymovirids. Our data indicate that this virus, for which the name blackberry virus S (BlVS) is proposed, is a hitherto undescribed species of the genus Marafivirus, family Tymoviridae. A survey conducted in Mississippi, USA, has shown that BlVS is also present in cultivated Rubus germplasm. This work represents the first report of a marafivirus infecting small fruits.     

Grapevine virus T is relatively widespread in Slovakia and Czech Republic and genetically diverse

A recently described putative foveavirus, grapevine virus T (GVT), was detected in a Slovak grapevine accession (SK704) using high-throughput sequencing, prompting further studies. Full-length genome sequence of isolate GVT-SK704 was determined. Analyses revealed 86.1% nucleotide identity with the Italian GVT isolate, currently the only available nearly complete sequence of GVT in GenBank. A virus-specific RT-PCR assay was developed, which enabled a survey of GVT incidence in grapevine samples from Slovakia and Czech Republic. Unexpectedly, GVT was present in ~?30% of tested samples. Analysis of complete CP gene sequences of 20 Slovak and Czech GVT isolates detected in the survey revealed relatively high intra-species variability (up to 11.2% nucleotide divergence), suggesting multiple introductions from different sources, possibly over an extended period of time.     

Growth patterns and cell kinetics of human osteosarcoma xenografts in serial passages in nude mice analysed byin vivo labelling with iododeoxyuridine

A human osteoblastic osteosarcoma was transplanted in nude mice and followed in seven serial passages. Tumour growth, structure and cell proliferation were studied in order to test the validity of the experimental tumour model. Tumour cell kinetics was analysed by in vivo labelling with the thymidine analogue iododeoxyuridine (IdUrd). Immunohistochemistry was used to measure the IdUrd labelling index. Duration of S phase (t _S) was estimated by flow cytometry. From these two parameters potential doubling time (t _pot) was calculated. Cell kinetic parameters showed low variations between passages and also between xenografts in the same passage. Smaller variations oft _S compared to labelling index andt _pot were found.t _pot was generally short with an interpassageal mean of 1.3 days and CV=14.8%. All xenografts showed DNA aneuploidy (mean DNA index=1.6). Homogeneous tumour growth was indicated by low variations of volume doubling time and lag time. There was no correlation between tumour growth and cell proliferation. Histopathological characteristics of the donor patient's tumour were retained during serial transplantation.Abbreviations IdUrd iododeoxyuridine - BrdUrd bromodeoxyuridine - t _pot potential doubling time - t _S duration of S phase - t _VD volume doubling time     

Molecular basis for enhancement of the meiotic DMC1 recombinase by RAD51 associated protein 1 (RAD51AP1)

Homologous recombination is needed for meiotic chromosome segregation, genome maintenance, and tumor suppression. RAD51AP1 (RAD51 associated protein 1) has been shown to interact with and enhance the recombinase activity of RAD51. Accordingly, genetic ablation of RAD51AP1 leads to enhanced sensitivity to and also chromosome aberrations upon DNA damage, demonstrating a role for RAD51AP1 in mitotic homologous recombination. Here we show physical association of RAD51AP1 with the meiosis-specific recombinase DMC1 and a stimulatory effect of RAD51AP1 on the DMC1-mediated D-loop reaction. Mechanistic studies have revealed that RAD51AP1 enhances the ability of the DMC1 presynaptic filament to capture the duplex-DNA partner and to assemble the synaptic complex, in which the recombining DNA strands are homologously aligned. We also provide evidence that functional cooperation is dependent on complex formation between DMC1 and RAD51AP1 and that distinct epitopes in RAD51AP1 mediate interactions with RAD51 and DMC1. Finally, we show that RAD51AP1 is expressed in mouse testes, and that RAD51AP1 foci colocalize with a subset of DMC1 foci in spermatocytes. These results suggest that RAD51AP1 also serves an important role in meiotic homologous recombination.     

Uncemented cups with and without screw holes in primary THA: a Swedish Hip Arthroplasty Register study with 22,725 hips

Background and purpose — Uncemented cups in total hip arthroplasty (THA) are often augmented with additional screws to enhance their primary stability. We investigated whether there is a difference in the risk for revision between cups with screw holes and cups without screw holes.

Patients and methods — We analyzed the risk for cup revision of uncemented cups registered in the Swedish Hip Arthroplasty Register (SHAR) between 2000 and 2017 with respe ct to the presence of screw holes. Only patients with primary osteoarthritis (OA) were included. 22,725 cups, including 12,354 without screw holes and 10,371 with screw holes, were evaluated. Revision rates at 2 and 10 years after the primary operation were analyzed.

Results — At a median follow-up time of 3.4 years (0–18), 459?cup revisions were reported. The main reasons for cup revision during the whole observation time were infection, 52% of all cup revisions, and dislocation, 26% of all cup revisions. The survival rate with cup revision due to aseptic loosening as endpoint was 99.9% (95% CI 99.8–99.9) at 2 years for both cups with and cups without screw holes, and the survival rates at 10 years were 99.5% (CI 99.3–99.7) and 99.1% (CI 98.6–99.5), respectively. Cups without screw holes showed a decreased risk of revision due to any reason at both 2 years (adjusted hazard ratio [HR] 0.6, CI 0.5–0.8) and 10 years (HR 0.7, CI 0.5–0.9).

Interpretation — We found a very low revision rate for aseptic loosening with modern, uncemented cup designs. Cups with screw holes had an increased risk of revision due to any reason in patients with primary OA