Search results for "papilloma"
showing 10 items of 266 documents
Effetti del Papillomavirus genitale sulla riproduzione umana
2009
Human papillomaviruses (HPVs) are agents of the most common sexually transmitted disease that can infect both females and males. More than 100 HPV-genotypes are known, of these, 40 genotypes infect the low genital tract. Based on their association with cervical cancer and precursor lesions, genital HPVs can also be grouped to high-risk and low-risk HPV-types. Diagnosis of HPV infection is sometime difficult because the infection is often transient and asymptomatic. High-risk HPV types are more likely to persist than are low-risk HPV types. It’s the inability of the immune system to spontaneously clear HPV that leads to development of precancerous cervical lesions. It is generally assumed th…
Commonalities between ENT Specialists and Oral Medicine Experts: Old HPV Diseases and New Oral HPV-Cancer along the Borders
2021
A human papillomavirus (HPV) infection is globally one of the most common causes of sexually transmitted infections of the mucous membranes (genital, anal and oral). Over the last decade, an increasing number of young patients have been infected due to the changes in sexual habits in the general population. The majority of the lesions are benign; however, substantial scientific evidence has suggested a role for the HPV family in the carcinogenesis of squamous cell carcinoma (SCC). It is proposed that dentists, in addition to ENT specialists, should apply standardized management protocols in order to construct a well-defined pathway in terms of diagnosis, which is based on a PCR diagnostic t…
Transformation of proliferative verrucous leukoplakia to oral carcinoma: a ten years follow-up
2004
Los autores presentan un caso de leucoplasia verrugosa proliferativa (LVP) en varón de 78 años de edad. Fue inicialmente presentado como un caso de leucoplasia en lengua pero un estudio microscópico en 1991 reveló la presencia de displasia epitelial leve. Tras 5 años de seguimiento, la lesión sufrió cambios de tamaño y localización y tuvo comportamiento recidivante. En 1996, un área eritematosa granular e indurada que apareció en lengua resultó ser un carcinoma de células escamosas microinvasivo cuando se estudió microscópicamente. Tras una revisión del comportamiento clinicopatológico de esta entidad, los autores concluyeron que se trataba de una leucoplasia verrugosa proliferativa, cuyo d…
Transfection of lipoma cells with papilloma bovine virus subgenomic fragment.
1991
Abstract Lipoma cells with consistent chromosomal aberration have been transfected with plasmids carrying papilloma bovine virus subgenomic fragment (PBV 69). The succesful transformation of the cells was ascerted on the changed growth pattern of the cells in liquid medium, colony formation in soft agar and modified cell appearrance in electron microscopy; transfection with PBV 69 has not been, however, sufficient to immortalize lipoma cells.
Binding and internalization of human papillomavirus type 33 virus-like particles by eukaryotic cells
1995
Infection of cells by human papillomaviruses (HPVs) associated with malignant genital lesions has not been studied because of the lack of an in vitro system and the unavailability of virions. We have now used virus-like particles (VLPs) of HPV type 33 to analyze the initial events in the interaction of the HPV capsid with cell lines. Binding of VLPs to HeLa cells was observed in biochemical assays and by immunofluorescence. VLP binding was inhibited by antisera raised against VLPs but not by monoclonal antibodies recognizing either L1 or L2 epitopes accessible on VLPs. Under saturating conditions, approximately 2 x 10(4) VLPs were bound per cell, with a dissociation constant of about 100 pM…
Assembly and Translocation of Papillomavirus Capsid Proteins
2002
ABSTRACT The major and minor capsid proteins of polyomavirus are preassembled in the cytoplasm and translocated to the nucleus only as a VP1-VP2/VP3 complex. In this study, we describe independent nuclear translocation of the L1 major protein and the L2 minor capsid protein of human papillomavirus type 33 by several approaches. First, we observed that expression and nuclear translocation of L2 in natural lesions precede expression of L1. Second, using a cell culture system for coexpression, we found that accumulation of L2 in nuclear domain 10 (ND10) subnuclear structures precedes L1 by several hours. In contrast, complexes of L2 and mutants of L1 forced to assemble in the cytoplasm are tra…
Nuclear localization but not PML protein is required for incorporation of the papillomavirus minor capsid protein L2 into virus-like particles.
2004
ABSTRACT Recent reports suggest that nuclear domain(s) 10 (ND10) is the site of papillomavirus morphogenesis. The viral genome replicates in or close to ND10. In addition, the minor capsid protein, L2, accumulates in these subnuclear structures and recruits the major capsid protein, L1. We have now used cell lines deficient for promyelocytic leukemia (PML) protein, the main structural component of ND10, to study the role of this nuclear protein for L2 incorporation into virus-like particles (VLPs). L2 expressed in PML protein knockout (PML −/− ) cells accumulated in nuclear dots, which resemble L2 aggregates forming at ND10 in PML protein-containing cells. These L2 assemblies also attracted…
Generation and neutralization of pseudovirions of human papillomavirus type 33
1997
Since human papillomaviruses (HPV) cannot be propagated in cell culture, the generation of infectious virions in vitro is a highly desirable goal. Here we report that pseudovirions can be generated by the assembly of virus-like particles (VLPs) in COS-7 cells containing multiple copies of a marker plasmid. Using recombinant vaccinia viruses, we have obtained spherical VLPs of HPV type 33 (HPV-33) which fractionate into heavy and light VLPs in cesium chloride density gradients. VLPs in the heavy fraction (1.31 g/cm3) carry the plasmid in DNase-resistant form and are capable of transferring the genetic marker located on the plasmid to COS-7 cells in a DNase-resistant way (pseudoinfection). Th…
DNA-induced structural changes in the papillomavirus capsid.
2001
ABSTRACT Human papillomavirus capsid assembly requires intercapsomeric disulfide bonds between molecules of the major capsid protein L1. Virions isolated from naturally occurring lesions have a higher degree of cross-linking than virus-like particles (VLPs), which have been generated in eukaryotic expression systems. Here we show that DNA encapsidation into VLPs leads to increased cross-linking between L1 molecules comparable to that seen in virions. A higher trypsin resistance, indicating a tighter association of capsomeres through DNA interaction, accompanies this structural change.
Human Papillomavirus Types 16, 18, and 31 Share Similar Endocytic Requirements for Entry
2013
ABSTRACT Human papillomavirus type 18 (HPV18), one of the HPVs with malignant potential, enters cells by an unknown endocytic mechanism. The key cellular requirements for HPV18 endocytosis were tested in comparison to those for HPV16 and -31 endocytoses. HPV18 (like HPV16 and -31) entry was independent of clathrin, caveolin, dynamin, and lipid rafts but required actin polymerization and tetraspanin CD151, and the viruses were routed to the same LAMP-1-positive compartment. Hence, the viruses shared similar cellular requirements for endocytic entry.