236 research outputs found

    Welcoming low testosterone as a cardiovascular risk factor

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    Male hypogonadism now has a new spectrum of complications. They are mainly cardiometabolic in nature. Low serum testosterone levels are a risk factor for diabetes, metabolic syndrome, inflammation and dyslipidemia. These metabolic and inflammatory complications are not without consequences. Recent studies have shown low serum testosterone levels to be an independent risk factor of cardiovascular and all-cause mortality. It is time to welcome low serum testosterone levels as a cardiovascular risk factor

    A One-Step Real-Time Multiplex PCR for Screening Y-Chromosomal Microdeletions without Downstream Amplicon Size Analysis

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    BACKGROUND: Y-chromosomal microdeletions (YCMD) are one of the major genetic causes for non-obstructive azoospermia. Genetic testing for YCMD by multiplex polymerase chain reaction (PCR) is an established method for quick and robust screening of deletions in the AZF regions of the Y-chromosome. Multiplex PCRs have the advantage of including a control gene in every reaction and significantly reducing the number of reactions needed to screen the relevant genomic markers. PRINCIPAL FINDINGS: The widely established "EAA/EMQN best practice guidelines for molecular diagnosis of Y-chromosomal microdeletions (2004)" were used as a basis for designing a real-time multiplex PCR system, in which the YCMD can simply be identified by their melting points. For this reason, some AZF primers were substituted by primers for regions in their genomic proximity, and the ZFX/ZFY control primer was exchanged by the AMELX/AMELY control primer. Furthermore, we substituted the classical SybrGreen I dye by the novel and high-performing DNA-binding dye EvaGreen™ and put substantial effort in titrating the primer combinations in respect to optimal melting peak separation and peak size. SIGNIFICANCE: With these changes, we were able to develop a platform-independent and robust real-time based multiplex PCR, which makes the need for amplicon identification by electrophoretic sizing expendable. By using an open-source system for real-time PCR analysis, we further demonstrate the applicability of automated melting point and YCMD detection

    Genetic instability and anti-HPV immune response as drivers of infertility associated with HPV infection

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    Funding Information: RFBR grant 17–54-30002, Ministry of Science and Higher Education of the Russian Federation (Agreement No. 075–15–2019-1660) to Olga Smirnova. Publisher Copyright: © 2021, The Author(s).Human papillomavirus (HPV) is a sexually transmitted infection common among men and women of reproductive age worldwide. HPV viruses are associated with epithelial lesions and cancers. HPV infections have been shown to be significantly associated with many adverse effects in reproductive function. Infection with HPVs, specifically of high-oncogenic risk types (HR HPVs), affects different stages of human reproduction, resulting in a series of adverse outcomes: 1) reduction of male fertility (male infertility), characterized by qualitative and quantitative semen alterations; 2) impairment of couple fertility with increase of blastocyst apoptosis and reduction of endometrial implantation of trophoblastic cells; 3) defects of embryos and fetal development, with increase of spontaneous abortion and spontaneous preterm birth. The actual molecular mechanism(s) by which HPV infection is involved remain unclear. HPV-associated infertility as Janus, has two faces: one reflecting anti-HPV immunity, and the other, direct pathogenic effects of HPVs, specifically, of HR HPVs on the infected/HPV-replicating cells. Adverse effects observed for HR HPVs differ depending on the genotype of infecting virus, reflecting differential response of the host immune system as well as functional differences between HPVs and their individual proteins/antigens, including their ability to induce genetic instability/DNA damage. Review summarizes HPV involvement in all reproductive stages, evaluate the adverse role(s) played by HPVs, and identifies mechanisms of viral pathogenicity, common as well as specific for each stage of the reproduction process.publishersversionPeer reviewe

    Climatic and cultural changes in the west Congo Basin forests over the past 5000 years

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    Central Africa includes the world's second largest rainforest block. The ecology of the region remains poorly understood, as does its vegetation and archaeological history. However, over the past 20 years, multidisciplinary scientific programmes have enhanced knowledge of old human presence and palaeoenvironments in the forestry block of Central Africa. This first regional synthesis documents significant cultural changes over the past five millennia and describes how they are linked to climate. It is now well documented that climatic conditions in the African tropics underwent significant changes throughout this period and here we demonstrate that corresponding shifts in human demography have had a strong influence on the forests. The most influential event was the decline of the strong African monsoon in the Late Holocene, resulting in serious disturbance of the forest block around 3500 BP. During the same period, populations from the north settled in the forest zone; they mastered new technologies such as pottery and fabrication of polished stone tools, and seem to have practised agriculture. The opening up of forests from 2500 BP favoured the arrival of metallurgist populations that impacted the forest. During this long period (2500–1400 BP), a remarkable increase of archaeological sites is an indication of a demographic explosion of metallurgist populations. Paradoxically, we have found evidence of pearl millet (Pennisetum glaucum) cultivation in the forest around 2200 BP, implying a more arid context. While Early Iron Age sites (prior to 1400 BP) and recent pre-colonial sites (two to eight centuries BP) are abundant, the period between 1600 and 1000 BP is characterized by a sharp decrease in human settlements, with a population crash between 1300 and 1000 BP over a large part of Central Africa. It is only in the eleventh century that new populations of metallurgists settled into the forest block. In this paper, we analyse the spatial and temporal distribution of 328 archaeological sites that have been reliably radiocarbon dated. The results allow us to piece together changes in the relationships between human populations and the environments in which they lived. On this basis, we discuss interactions between humans, climate and vegetation during the past five millennia and the implications of the absence of people from the landscape over three centuries. We go on to discuss modern vegetation patterns and African forest conservation in the light of these events.Peer reviewe

    Identification of Multiple HPV Types on Spermatozoa from Human Sperm Donors

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    Human papillomaviruses (HPV) may cause sexually transmitted disease. High-risk types of HPV are involved in the development of cervical cell dysplasia, whereas low-risk types may cause genital condyloma. Despite the association between HPV and cancer, donor sperm need not be tested for HPV according to European regulations. Consequently, the potential health risk of HPV transmission by donor bank sperm has not been elucidated, nor is it known how HPV is associated with sperm. The presence of 35 types of HPV was examined on DNA from semen samples of 188 Danish sperm donors using a sensitive HPV array. To examine whether HPV was associated with the sperm, in situ hybridization were performed with HPV-6, HPV-16 and -18, and HPV-31-specific probes. The prevalence of HPV-positive sperm donors was 16.0% and in 66.7% of these individuals high-risk types of HPV were detected. In 5.3% of sperm donors, two or more HPV types were detected. Among all identified HPV types, 61.9% were high-risk types. In situ hybridization experiments identified HPV genomes particularly protruding from the equatorial segment and the tail of the sperm. Semen samples from more than one in seven healthy Danish donors contain HPV, most of them of high-risk types binding to the equatorial segment of the sperm cell. Most HPV-positive sperm showed decreased staining with DAPI, indicative of reduced content of DNA. Our data demonstrate that oncogenic HPV types are frequent in men

    Choline Dehydrogenase Polymorphism rs12676 Is a Functional Variation and Is Associated with Changes in Human Sperm Cell Function

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    Approximately 15% of couples are affected by infertility and up to half of these cases arise from male factor infertility. Unidentified genetic aberrations such as chromosomal deletions, translocations and single nucleotide polymorphisms (SNPs) may be the underlying cause of many cases of idiopathic male infertility. Deletion of the choline dehydrogenase (Chdh) gene in mice results in decreased male fertility due to diminished sperm motility; sperm from Chdh−/− males have decreased ATP concentrations likely stemming from abnormal sperm mitochondrial morphology and function in these cells. Several SNPs have been identified in the human CHDH gene that may result in altered CHDH enzymatic activity. rs12676 (G233T), a non-synonymous SNP located in the CHDH coding region, is associated with increased susceptibility to dietary choline deficiency and risk of breast cancer. We now report evidence that this SNP is also associated with altered sperm motility patterns and dysmorphic mitochondrial structure in sperm. Sperm produced by men who are GT or TT for rs12676 have 40% and 73% lower ATP concentrations, respectively, in their sperm. rs12676 is associated with decreased CHDH protein in sperm and hepatocytes. A second SNP located in the coding region of IL17BR, rs1025689, is linked to altered sperm motility characteristics and changes in choline metabolite concentrations in sperm

    Mechanism of Inhibition of Enveloped Virus Membrane Fusion by the Antiviral Drug Arbidol

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    The broad-spectrum antiviral arbidol (Arb) inhibits cell entry of enveloped viruses by blocking viral fusion with host cell membrane. To better understand Arb mechanism of action, we investigated its interactions with phospholipids and membrane peptides. We demonstrate that Arb associates with phospholipids in the micromolar range. NMR reveals that Arb interacts with the polar head-group of phospholipid at the membrane interface. Fluorescence studies of interactions between Arb and either tryptophan derivatives or membrane peptides reconstituted into liposomes show that Arb interacts with tryptophan in the micromolar range. Interestingly, apparent binding affinities between lipids and tryptophan residues are comparable with those of Arb IC50 of the hepatitis C virus (HCV) membrane fusion. Since tryptophan residues of membrane proteins are known to bind preferentially at the membrane interface, these data suggest that Arb could increase the strength of virus glycoprotein's interactions with the membrane, due to a dual binding mode involving aromatic residues and phospholipids. The resulting complexation would inhibit the expected viral glycoprotein conformational changes required during the fusion process. Our findings pave the way towards the design of new drugs exhibiting Arb-like interfacial membrane binding properties to inhibit early steps of virus entry, i.e., attractive targets to combat viral infection
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