323,061 research outputs found
JC polyomavirus infections in transplant patients
No full textThe polyomavirus JC virus (JCV) is a small nonenveloped DNA virus that asymptomatically infects about 80% of healthy adults and establishes latency in the kidney tissue. In case of immunodeficient hosts, JCV can lytically infect the oligodendrocytes, causing a fatal demyelinating disease, known as Progressive Multifocal Leukoencephalopathy (PML). Although the reactivation of another human polyomavirus, BK Virus (BKV), is relatively common and its association with the Polyomavirus Associated Nephropathy (PVAN) following renal transplantation is assessed, JCV replication and its impact on graft function and survival is less well studied. In addition, none of the performed studies ruled out the hypothesis that JCV could be associated with certain post-trasplantation clinical syndromes. Thus, monitoring of Polyomaviruses infection, especially during the first 24 months post-transplantation, is recommended
Ritrovamento, caratterizzazione molecolare ed analisi di espressione del virus JC nei tumori cerebrali umani
No full textHuman Polyomaviruses can establish a latent infection in the kidney of up to 80% of the adult population worldwide and JCV induces progressive multifocal leukoencephalopathy (PML) in immunodeficient individuals. Recently several mounting evidences point to the association of Polyomaviruses with human cancer, more notably brain tumors. To further investigate this hypothesis, brain biopsy tissue, cerebrospinal fluid (CSF) and peripheral blood (PB) were collected from 40 Italian individuals suffering of brain tumors. Using PCR we investigated the presence of LT-Antigen (LT) DNA fragment common to JCV, BKV and SV40. JCV DNA was found in 37.5% of tumor tissues, 11.1% of CSF and 5.4% of PB, whereas BKV DNA was found in 20 % of biopsies and SV40 was not detected in the studied samples. Since 55.5% of tissues from glioblastomas and 37.5% from meningiomas were positive for JCV LT DNA, we focused our attention on this viral agent. The study of JCV genotype distribution, based on sequencing of VP1, showed that mostly of the amplified strains were JCV type 1, whereas the analysis of TCR nucleotide sequence indicated the IR (Mad 4) organization as the most frequent. The late gene Agnoprotein DNA was amplified in 7 biopsies, 6 of which were glioblastomas. Moreover, we found, by means of RT-PCR, that LT-antigen was actively transcribed in 60 % of the JCV - positive tested biopsies. Altogether, the results from gene amplifications and gene expression analysis of the various brain tumor samples add further elements in favor of the possible association of JCV with CNS tumors, and especially with glioblastoma
Infezioni virali congenite perinatali e neonatali
No full textViral infections may be vertically transmitted from mother to child at different times, ranging from in utero transmission, which occurs during pregnancy, perinatal transmission, which takes place during delivery and postnatal transmission, which is usually the consequence of breastfeeding. Mother-to-child transmission, which may occur after primary, recurrent or chronic maternal infection, is potentially harmful to the fetus or the newborn since it may result in miscarriage, fetal death, congenital anomalies, intrauterine growth restriction, or severe neonatal disease. Some risk factors are thought to affect the rate of mother-to-child transmission, such as the presence of other viral infections, maternal viral load, type of infection (primary versus recurrent), obstetrical procedures (prolonged rupture of membranes, mode of delivery), social-economical conditions and breastfeeding. For some of the vertically transmitted viruses, interventions are nowadays available to prevent mother-to-child transmission, such as vaccines, passive immunization, antiviral drugs. Moreover, perinatal and postnatal infections may be prevented by the use of elective caesarean delivery and avoidance of breastfeeding
Application of molecular tools for the diagnosis of central nervous system infections
No full textMany infectious agents can cause central nervous system (CNS) diseases in humans. Since microbial agents infecting CNS are numerous and have different features, conventional laboratory tests may not be sensitive enough to identify and characterise viruses and bacteria in human biological specimens. Thus, the need to define methods for the diagnosis of infectious neurological diseases, such as progressive multifocal leukoencephalopathy (PML), is urgent, in order to improve the outcome of the diseases with rapid and accurate detection of the pathogens
Review on the Relationship between Human Polyomaviruses-Associated Tumors and Host Immune System
No full textThe polyomaviruses are small DNA viruses that can establish latency in the human host. The name polyomavirus is derived from the Greek roots poly-, which means “many,” and -oma, which means “tumours.” These viruses were originally isolated in mouse (mPyV) and in monkey (SV40). In 1971, the first human polyomaviruses BK and JC were isolated and subsequently demonstrated to be ubiquitous in the human population. To date, at least nine members of the Polyomaviridae family have been identified, some of them playing an etiological role in malignancies in immunosuppressed patients. Here, we describe the biology of human polyomaviruses, their nonmalignant and malignant potentials ability, and their relationship with the host immune response
Ipotesi eziologiche ancora attuali nel campo dei disturbi mentali = Current hypothesis on the etiology of mental disorders
No full textIntroduction: Schizophrenia and related psychiatric disorders are diseases with unknown origin. Family and adoption studies indicate a strong genetic component of disease susceptibility. However, epidemiological studies also point to a role for infections and other environmental factors in the etiology of this complex disease. In particular, many studies support the hypothesis that the exposure to infective agents, such as bacteria and viruses, may be a risk factor for the development of mental disorders. Materials and methods: In this brief review we will at first describe the viral agents that can be directly, and by different means, associated with mental illness. Then, the scientific literature which has focused on the association between schizophrenia and the most relevant etiopathogentic hypothesis will be analyzed and discussed. Conclusions: All data analyzed suggest the presence of elements in favor of the involvement of viruses in the pathogenesis of some mental diseases. However, there are no definitive data and it will be necessary to define multicenter research projects, in order to verify, by means of advanced technologies, these interesting theories
Review on the role of the human Polyomavirus JC in the development of tumors
No full textAlmost one fifth of human cancers worldwide are associated with infectious agents, either bacteria or viruses, and this makes the possible association between infections and tumors a relevant research issue. We focused our attention on the human Polyomavirus JC (JCPyV), that is a small, naked DNA virus, belonging to the Polyomaviridae family. It is the recognized etiological agent of the Progressive Multifocal Leukoencephalopathy (PML), a fatal demyelinating disease, occurring in immunosuppressed individuals. JCPyV is able to induce cell transformation in vitro when infecting non-permissive cells, that do not support viral replication and JCPyV inoculation into small animal models and non human primates drives to tumor formation. The molecular mechanisms involved in JCPyV oncogenesis have been extensively studied: the main oncogenic viral protein is the large tumor antigen (T-Ag), that is able to bind, among other cellular factors, both Retinoblastoma protein (pRb) and p53 and to dysregulate the cell cycle, but also the early proteins small tumor antigen (t-Ag) and Agnoprotein appear to cooperate in the process of cell transformation. Consequently, it is not surprising that JCPyV genomic sequences and protein expression have been detected in Central Nervous System (CNS) tumors and colon cancer and an association between this virus and several brain and non CNS-tumors has been proposed. However, the significances of these findings are under debate because there is still insufficient evidence of a casual association between JCPyV and solid cancer development. In this paper we summarized and critically analyzed the published literature, in order to describe the current knowledge on the possible role of JCPyV in the development of human tumor
Natalizumab treatment of multiple sclerosis: new insights
No full textNatalizumab is a monoclonal antibody directed against the α4 chain of the very late activating antigen 4 and α4β7 integrins, present on the leukocytes surface, used as monotherapy for the treatment of relapsing-remitting multiple sclerosis. It substantially reduces relapse rate and the accumulation of disability, but its use is associated with a very adverse event, that is the development of progressive multifocal leukoencephalopathy, a fatal demyelinating disease of the CNS, due to the lytic replication of the human polyomavirus JC. The main focus of the review is to describe the newest insights on natalizumab, its current use in the clinical practice, the natalizumab-treated patients' management and the risk stratification related to the progressive multifocal leukoencephalopathy development
The long and evolving relationship between viruses and multiple sclerosis
No full textMultiple sclerosis (MS) is a demyelinating disorder of unknown etiology, possibly caused by a virus or is virus-triggered. Several viruses, including herpesviruses, were suggested as etiologic agents or risk factors for exacerbation in the course of illness but none have been shown to be irrefutably linked. Recently the interest of researchers and clinicians in the association between viruses and MS was reawakened by the development of progressive multifocal leukoencephalopathy, a demyelinating and fatal disease caused by JC polyomavirus replication, in natalizumab-treated MS patients. In this review, we will illustrate the evidence underlying the viral hypothesis for MS pathogenesis and will review the main features of the potential viral candidates. We will also describe the risks associated with newer MS therapies and with viral/bacterial vaccination
The manifestation of AIDS in Africa: An epidemiological overview
No full textThe HIV epidemic in Africa has changed over the last decade and the incidence of AIDS, which was very low at the beginning of nineties, is now dramatically increasing. In this paper, we analyze the current situation of AIDS epidemiology on the continent, based on data generated by the antenatal care surveillance systems. As described here, the spread and prevalence of HIV differ in each African country, with South Africa now facing the worst situation. In addition, we have focused our attention on the modes and risks of viral transmission, highlighting the spread of HIV in particular subpopulations, which, for different reasons, prove to be more affected by the epidemic, such as sex workers and children. Genotype evolution and distribution in the various geographical areas are also considered. From this brief overview, it appears clear that poverty, the lack of technologies and inadequate resources, due mostly to social and economic instability, are widening the already existent gap between Africa and industrialized countries. (copyright) 2005 Journal of NeuroVirology
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