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At least 19 recordsLinked to original sources

Progressive multifocal leukoencephalopathy. A cause of visual loss.

A patient had been treated for chronic lymphocytic leukemia for five years before developing visual blurring as the manifestation of occipital lobe lesions of progressive multifocal leukoencephalopathy (PML). The disease is caused by an infection of the CNS oligodendrocytes by a papovavirus, whose replication is facilitated by an impairment of the host's cell-mediated immunologic system. The multiplying virus destroys the oligodendrocytes and causes extensive demyelination of the white matter of the brain. Antiviral agents, such as cytarabine, may be beneficial in treating patients with PML.

Cytarabine

Epidermodysplasia verruciformis.

Epidermodysplasia verruciformis (EV) is characterized by the early onset of extensive, persistent verruca plana that may undergo malignant transformation. Immunologic studies of a case of EV confirmed by electron microscopic identification of the virus disclosed no detectable abnormalities. The importance of this uncommon clinical syndrome lies in its demonstration that benign papovavirus, the etiologic agent of warts, can produce malignant neoplasms in genetically susceptible hosts.

Antibodies, Viral

Viruses and cancer of the lower genital tract.

The importance of viruses as oncogenic agents in animals is well established. Recent work suggests that viruses may also be etiologically related to some human cancers. Herpes simplex virus type 2 (HSV-2) and the genital wart virus are prime suspects in carcinomas involving the female lower genital tract. In particular, a close association has been found between HSV-2 infection and cervical neoplasia in cytohistopathologic and seroepidemiologic studies. Preliminary results of prospective studies show further that women with genital herpetic infection are at increased risk of developing cervical neoplasia. Additional studies are also in progress on animal models, including subhuman primates, and efforts continue in the attempt to confirm the presence of viral genetic material or its expression in human cervical cancer cells. The possibility that human wart viruses have an oncogenic potential is suggested by clinicopathologic and electron microscopic observations. Further research is needed to ascertain the precise role of viruses in genital cancer.

Adenoviridae

The morphology of human papillomas of the upper respiratory tract.

Recurrent squamous papillomas of the upper respiratory tract were examined by light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Surface of the cells is irregular and is covered by numerous stout microvilli. These are shorter and broader than those of cells of the uninvolved mucosa. The villi often seem umbilicated at the apex; the remainder of them, however, are rounded. The epithelium participating in the formation of papillomas shows some maturation of the cells but this does not progress normally. The predominating area is the thickened spinous layer representing the bulk of the lesion. The basal layer shows mildly increased activity but the basement membrane is intact. The cells often are very closely packed but in some areas, more particularly in the deep layer, they are loosely arranged. The intercellular space contains a moderately electron-dense finely fibrillar material. No abnormal mitoses are found. The neighboring univolved epithelium often shows increased growth activity and some inflammation. The larygneal papillomas propably represent an overgrowth of epithelium which may develop following hindered desquamation caused and/or heralded by a chronic inflammatory condition probably of viral origin and may be preceded by epithelial metaplasia and hyperplasia.

Adult

Interspecies-, species- and type-specific T antigenic determinants of human papovaviruses (JC and BK) and of Simian virus 40.

Immunofluorescence tests, absorption studies and quantitative analysis by a very sensitive 51Cr microcomplement fixation (CF) technique were used to define the degree of relatedness between the tumor (T) antigens induced by human papovaviruses, strain JC and BK, with simian virus 40(SV40) and mouse polyoma virus (PyV). Antisera against JCV, BKV, SV40 and PyV T were raised in tumor-bearing hamsters. The data obtained indicate that T antigens of JCV, BKV and SV40 possess various subspecificities which can be distinguished and looked upon as interspecies-, species- and type-specific antigenic determinants. It was found that JCV T and BKV T synthesized in transformed hamster cells share about the same amount (20%) of interspecies cross-reacting antigen with SV40 T from H-50 cell extracts (transformed hamster cells). Although hamster cells transformed by PyV showed definite PyV T reactivity, no cross-reactivity, at least with the sera used, was found with human papovavirus and SV40 T antigens. Furthermore, degree of heterogeneity was observed within the T antigen complex derived from different SV40-transformed cells.

Animals

Microfluorometric analysis of anti-complement and indirect immunofluorescence tests for human papovavirus (JCV and BKV) T antigens.

The anti-complement immunofluorescence (ACIF) test was compared with the conventionally used indirect IF (IIF) in regard to its usefulness for the detection of low amounts of human papovavirus tumor (T) antigen. Fluorescence microscopic analysis revealed that it is significantly more sensitive. Microfluorometric measurements on the intensity of staining of T-antigen-positive nuclei demonstrated that JCV T in HJC-15 cells was 35-fold and BKV T in BK-L3 cells 94-fold more intensively stained in the ACIF then in the IIF. It appears that the lower the actual amount of a given antigen the more valuable is the ACIF test.

Animals

Isolation of a SV40-like Papovavirus from a human glioblastoma.

A human glioblastoma multiforme (M27) tested in early cell cultures by indirect immunofluorescence staining showed SV40-related tumor (T)-antigen, 95% of the cells being positive. SV40-related viral capsid (V)-antigen was absent in all cells tested. Experiments to rescue this virus were performed by fusing M27 cells with CV-I monkey cells, which were permissive for SV40, using polyethylene glycol (PEG) as fusion factor. We succeeded in isolating virus particles SV40-GBM which electron microscopy showed to correspond in size and morphology to papovaviruses. Serological tests (hemagglutination, neutralization, fluorescent antibody) revealed that the virus is indistinguishable from SV40. Despite this apparent antigenic identity SV40-GBM differs slightly from SV40 wild type. This virus can propagate and produce CPE in both CV-I cells and primary fetal human kidney cells. Furthermore digestion of SV40-GBM DNA with the HindII/III restriction endonucleases revealed minor differences compared with the SV40 DNA. Therefore the virus SV40-GBM obtained from glioblastoma cells seems to be closely related to the SV40-PML viruses described earlier.

Antigens, Viral

Cell specificity of transcription regulation by papovavirus T antigens and DNA replication.

Simian virus 40 (SV40) and polyomavirus (Py) DNA replication require cellular proteins and a virus-encoded early gene product, large T antigen (SVT and PyT, respectively). Primate cells contain factors permissive for SV40 replication, whereas murine cells express those factors permissive for Py. We have compared the roles T antigen, cell permissiveness and replication play in transcription of SV40 and Py genes. We show that in their respectively permissive cells, SV40 replication causes a major shift in transcription initiation from the early to the late viral promoter, whereas when Py replicates a comparable shift does not occur. This difference is discussed in relation to differences in the organization of the origin and promoter region between these two papovaviruses. Reporter plasmids were constructed that carried both viral origins, one at the natural position in the promoter being tested and the other at a distal location. With the appropriate TAg, these vectors could be made to replicate in either primate (HeLa) or rodent (3T6) cells. The SV40 early to late shift occurred when replication was driven in HeLa cells, and was not seen on replicating templates in rodent cells. Thus, replication per se does not account for the shift. We show also that, like SVT, PyT is a potent activator of transcription, and that SVT and PyT can activate each other's late promoters independently of DNA replication, but only in cells permissive for DNA replication catalysed by the respective T antigen. Taken together, the data presented here suggest that papovaviruses may utilize permissive factors in transcription control mechanisms.

Animals

Clinical significance of viral latency.

Evidence is accumulating to show that a number of viruses have the ability to adapt to man's defense mechanisms and survive in a latent state for what appears to be the life of the human host. Unfortunately, latent viral presence, which may appear clinically benign initally, may manifest itself later as severe and often fatal disease. Some members of the herpes virus family have latent potential and are discussed in detail. Clinical competence would suggest a thorough understanding of these late manifestations of occult viral presence.

Adenoviridae

Atypical progressive multifocal leukoencephalopathy with plasma-cell infiltrates.

In rare cases of progressive multifocal leukoencephalopathy (PML) the lesions are atypical in that the characteristic alteration of oligodendrocytic nuclei is infrequent or absent, and the demyelinated foci contain mononuclear inflammatory infiltrates including numerous plasma cells. Otherwise these cases, both as to the topographic features of the lesions, and the background of chronic lymphoproliferative or myeloproliferative disease or immunosuppressive treatment, conform to the usual pattern. In the case here reported, that of a 54-year-old man receiving immunosuppressive drugs for chronic polymyositis, electron microscopy showed papovavirions in astrocytic nuclei and fluorescent antibody studies indicated that these represented JC virus. In this and the 3 previously reported similar cases of atypical PML, the neurologic illness was less devastating than generally occurs in classic PML. Possibly these cases represent instances of unusually strong host-resistance against the disease.

Astrocytes

Papova virus-like particles in a nigral type of Creutzfeldt-Jakob disease.

In this case of Cruetzfeldt-Jakob disease cortical biopsy demonstrated a large number of papova virus-like particles in the axons, dendrites, astroyctic processes and blood-vessel walls, while necropsy findings disclosed a striking status spongiosus and neuronal degeneration in the substantia nigra. The patient also suffered from a testicular feminization syndrome and was treated with immunosuppressive drugs for pemphigus vulgaris. The ready demonstration of viral particles, the rapid course of the disease and the unusual necropsy findings are discussed and related to the pre-existing diseases of the patient.

Cerebral Cortex

[Comparison of the epidermodysplasia verruciformis Lewandowsky-Lutz with the other Papova virus acanthomas by light and electron microscopy (author's transl)].

Based on histology and electron microscopy, a series of Papova virus acanthomas consisting of 300 common warts and Condylomata acuminata as well as primary efflorescences of 7 typical and 7 questionable cases of Epidermodysplasia verruciformis have been classified. Four cytological types expressing different cytopathogenic viral actions were established. Typ 4 ("basophilic foamy giant keratinocytes") seems to be specific for Epidermodysplasia verruciformis which thus can be differentiated histologically against ordinary warts (type 1-3).

Condylomata Acuminata