Human papillomavirus (HPV) infection in seborrheic keratosis

We studied 89 seborrheic keratoses. In four cases, light microscopy and electron microscopy demonstrated that seborrheic keratoses may be associated with human papillomavirus (HPV) infection.

Transdermal delivery of salicylic acid in the treatment of viral papillomas

Healthy adult (New Zealand, Dutch Belt, and Wild) rabbits were infected with rabbit papilloma virus (Shope variety). The resultant papillomas were treated with salicylic acid in a new transdermal drug delivery system utilizing a karaya gum glycol matrix. Biopsy samples of treated papillomas were taken at 1, 2, and 3 weeks after initiation of treatment and examined by electron microscopy. The observed changes during the course of treatment indicated that the karaya gum glycol matrix effectively released salicylic acid into the stratum corneum. Further, the rate of delivery of salicylic acid was such that the desired keratolytic activity was achieved with minimal inflammatory response.

[Ultrastructural observation of human papillomavirus particles in the uterine cervix intraepithelial neoplasia]

Using transmission electron microscopy (TEM), twenty two cases of an intraepithelial lesion in the uterine cervix have been examined for the presence of human papillomavirus (HPV) particles. In 21 of these cases (95%), HPV particles were detected in the nucleus, and in 5 cases, in the cytoplasm. The distribution of the intranuclear HPV particles was classified into 4 types. In only 2 cases did the exhibited particles show a geometrical crystalline array (type I). In most cases, the exhibited particles were either seen to show an aggregate non-crystalline array (type II) or were concentrated around the chromatin (type III). Some cases also were found to show particles that were scattered sporadically in the nucleoplasm (type IV).

Laryngeal papilloma cells in culture have an altered cytoskeleton

We have investigated the effect of human papillomavirus (HPV) transformation on cellular cytoarchitecture. Cells from laryngeal papillomas and normal epithelium were cultured in vitro. Cytoskeletal components of both types of cells were visualized by immunofluorescence, to determine whether there were any differences in the structure or distribution of the cytoskeleton. There was no significant change in microtubules. Two major components of the cytoskeleton, the intermediate filaments and the microfilaments, were altered in the papilloma cells. Polyacrylamide gel electrophoresis of isolated keratins showed differences between normal and papilloma tissue, which might explain the altered intermediate filament distribution. The changes in cytoskeletal structure may be one way in which HPVs alter cellular growth controls.

Retrovirus-induced osteopetrosis in mice. Ultrastructural evidence of early virus production in osteoblasts and osteocytes

Newborn female strain NMRI mice were given injections of a mouse retrovirus (OA MuLV) known to induce osteopetrosis, osteoma, and lymphoma. Femur metaphyses and lumbar vertebrae were investigated ultrastructurally 3 d, 7 d and 28 d after infection. Budding, immature and mature virus was observed associated with osteoblasts and osteocytes, but not with osteoclasts or chondrocytes, 28 d after infection with the virus. No production of virus particles was observed in bone-tissue in mock-treated controls. Thus, the primary target cell for OA virus in bone appears to belong to the osteoblastic/osteocytic cell lineage.

Induction of undifferentiated tumors by JC virus in the cerebrum of rats

Newborn Sprague-Dawley rats were inoculated intracranially with JC virus (Tokyo-1), a human polyomavirus, which had been isolated by Nagashima et al. from the autopsied brain of a patient with progressive multifocal leukoencephalopathy in Japan. Twenty-one to 70 weeks later, 21 of 27 rats developed brain tumors in the cerebrum, but not in the cerebellum. Most of the tumor cells were of an undifferentiated neuroectodermal nature and showed nuclear palisades and pseudorosettes. In some tumor cells glial fibrillary acidic protein was positive immunohistochemically, and many glial filaments were demonstrated ultrastructurally. Neuronal differentiation was not proved. Two continuous lines of cultured tumor cells were established, and T antigen of JCV (Tokyo-1) was present in both cell lines. Glial differentiation was confirmed also in the tumors produced by subcutaneous transplantation of cultured tumor cells.

Epidermodysplasia verruciformis. Clinical and light- and electron-microscopic observations during etretinate therapy

Three patients with epidermodysplasia verruciformis (EV) were treated with etretinate for 9-13 months. The patients had lesions characteristic of EV, including flat warts, common genital warts, pityriasis-versicolor-like lesions and malignant changes such as actinic keratosis and Bowenoid cancer in situ. During etretinate treatment, some flattening of the warts was observed in all three patients, and the lesions on the chest and back became less red and scaling. However, none of the lesions disappeared completely, and when the treatment was discontinued, the lesions relapsed. No malignant changes were detected during the period of therapy. Electron microscopy revealed the presence of typical large, clear cells containing viral particles in the upper epidermis. Etretinate therapy induced the same type of fine-structural changes as those seen in keratinization disorders and genodermatoses. The clear cells and virus particles persisted throughout the treatment period. More long-term, controlled studies are necessary to make possible an estimate of the curative and cancer-inhibitory effect of etretinate treatment in patients with EV.

Association of HPV with human genital tumors

Human papillomaviruses (HPV) are clearly responsible for the induction of genital lesions like condylomata acuminata, bowenoid papules, and flat condylomas. Moreover, the DNA of particular virus types (HPV 16 and 18) is found in a substantial number of invasively growing squamous cell carcinomas of the genital tract, suggesting an etiologic involvement of these viruses in tumor development. Since HPV 16 and 18 as well as other papillomaviruses (HPV 6 or 11) usually present within the benign genital warts can be found in dysplastic lesions of the uterine cervix known as putative precancerous lesions, determination of the virus type might be of diagnostic relevance. Since no type-specific serologic reagents are available, viruses can be identified by nucleic acid hybridization using radioactively labeled HPV DNAs that have been molecularly cloned as probes.

Immunofluorescence and electron microscopic investigations of epithelial hybrid cells derived from nasopharyngeal carcinoma (NPC-KT)

The present study was made to investigate some characteristics of the epithelial hybrid cells derived from nasopharyngeal carcinoma (NPC-KT cells) both in vivo and in vitro, using immunofluorescence and electron microscopic techniques. Immunofluorescence and electron microscopic studies have shown that the appearance of Epstein-Barr virus (EBV)-related early antigens, EB-viral capsid antigens and virus particles in nude-mouse-grown-tumour cells were rather repressed, in contrast to, in vitro culture of the NPC-KT cells. The tumours after transplantation of the NPC-KT cells to nude mice showed pathological pictures of poorly differentiated carcinoma with EBV-associated nuclear antigen and derived from the NPC-KT cells by means of cytogenetic studies. More importantly, we have detected EBV-related membrane antigens (MA) on the epithelial NPC-KT cells. To our knowledge, the presence of MA on the malignant epithelial cells of the nasopharynx have never been demonstrated. The results reported here show for the first time the presence of MA on nasopharyngeal carcinoma cells.

Verrucous carcinoma: a possible viral pathogenesis

Seventeen cases of verrucous carcinoma of the oral cavity were reviewed. It was found that cytologic features generally associated with viral modification were observed in 15 of these cases. This finding suggests that viruses may play some role in the pathogenesis of verrucous carcinoma. The hypothesis that an opportunistic, persistent virus may act in concert with frank carcinogens to promote the development of verrucous carcinoma is discussed.

Human papillomavirus lesions in association with cervical dysplasias and neoplasias

A series of 620 cervical biopsy specimens (precancerous and malignant) was assessed morphologically with special reference to the concomitant appearance of human papillomavirus lesions. Tissue samples from 346 of these biopsy specimens were stained for human papillomavirus antigens using the immunoperoxidase-peroxidase-anti-peroxidase (PAP) technique. Papillomavirus lesions were found in 55.6% of the biopsy specimens associated with all degrees of epithelial atypia. The mean age of the women with papillomavirus (condylomatous) changes was significantly lower (P less than .0001) than that of women without these lesions, ie, those who had dysplasia/neoplasia without concomitant papillomavirus changes. Flat and inverted condylomas were most frequent between the ages 20 and 39 and were accompanied by more severe dysplasias than the papillomatous condylomas. In immunoperoxidase-PAP staining, 56% of the papillomavirus lesions were positive, the positivity being inversely related to the degree of epithelial atypia, and bearing some correlation with the condyloma type (papillary 100%, inverted 70%, and flat 52%). Although the results show a clear-cut association of human papillomavirus lesions with premalignant, and to a lesser extent with malignant squamous cell lesions of young sexually active women, thus suggesting a relationship between the virus and cancer, a careful follow-up study is needed to fully elucidate this relationship.

BK virus-induced tumors in hamsters: a morphological, histochemical and ultrastructural study

Macroscopic morphology, histology and ultrastructure of BK virus (BKV)-induced hamster and mouse tumors were investigated. Groups of animals were immunosuppressed to study the relationship between immune system and BKV oncogenesis. Ependymomas had the highest incidence, followed by tumors of pancreatic islets, osteosarcomas, lymphomas and sarcomas, sometimes associated in the same animal. All the tumors were found to be BKV specific. Ependymomas showed the shortest latency, infiltrated surrounding tissues but did not metastasize. Pseudo-rosettes were common and basal bodies were observed. Atypia and necrosis were more often present in immunosuppressed animals both for the ependymomas and for the other oncotypes. Pancreatic insulomas were frequently multinodular, possibly because of multifocal origin and metastasized to the liver. Hormone secretory granules were often found on electron microscopy. Osteosarcomas metastasized to lungs and peritoneum and showed the presence of osteoid, chondroblastoid and mixoid areas. Characteristic giant cells were present. Immunosuppression did not enhance tumor incidence and did not influence the latency period. However, neoplastic growth appeared to be more rapid and with more aggressive behavior in immunodepressed animals. These findings suggest an influence of the immune system in tumor development, whereas the virus oncogenic process seems unaffected.

Papilloma-like virus infection in Bolivian side-neck turtles

Five Bolivian side-neck turtles had multifocal small, round to confluent, white skin lesions distributed over the head. Several gram-negative microorganisms were isolated from the lesions. Light microscopy revealed hyperkeratosis and hyperplasia of the epidermis. Ultrastructural evaluation demonstrated crystalline aggregates of virus particles within nuclei of cells in the stratum granulosum and free within the stratum corneum. On the basis of size, location, arrangement, and tissue affected, the particles resembled papillomaviruses.

SV-40 virus-induced neoplastic transformation of hamster brain cells in vitro. Studies with scanning and transmission electron microscopy

Neoplastic transformation of one-day-old hamster brain cells was produced by infection with SV-40 virus and verified by phase contrast microscopy, growth in semisolid media, and intracranial tumor production after inoculation of the cells into other one-day-old hamsters. Transformed cells were studied by transmission and scanning electron microscopy. The numerous alterations in cell surface structure and in nuclear and cytoplasmic organization suggest a marked increase in cell metabolism and in the rate of mitosis and cell division. Cilia with a nine-to-zero pattern of microtubule doublets were present in cells with intermediate size filaments which stained for glial fibrillary acidic protein. The findings indicate that infection of one-day-old hamster brain cells in culture by SV-40 virus results in their transformation to a neoplastic state and the transformed cells are differentiating neoplastic astrocytes.

Early invasive and in situ warty carcinoma of the vulva: clinical, histologic, and electron microscopic study with particular reference to viral association

Cases of carcinoma of the vulva with a warty appearance were reviewed. Altogether, 27 cases of warty carcinoma of the vulva were treated at the University of Minnesota Hospitals between 1976 and 1980, which accounted for 22.4% of all vulvar epithelial malignancies. As compared to the previous experience between 1951 and 1970, this relative frequency increased fourfold. Clinical history indicated that warty carcinoma of the vulva was not necessarily preceded by long lead periods of in situ lesions. The lesions seemed to occur in all ages after adolescence, were multifocal in one third of the cases, were frequently locally recurring, and were relatively benign despite their often large size. Many of them were originally diagnosed as condyloma acuminatum. Virus-like particles were seen in eight of the 12 cases (67%) examined with transmission electron microscopy, which included six cases of invasive lesions. These observations suggest that human papillomavirus (HPV) may be the important etiologic agent of this group of tumors. Warty carcinoma of the vulva must be clearly separated from conventional invasive squamous cell carcinoma of the vulva, as its clinical behavior and a possible etiology appear unique.

Induction of sister chromatid exchange by polyoma large viral tumor antigen in transformed rat fibroblasts

The frequency of sister chromatid exchange (SCE) was determined in rat fibroblasts transformed by wild-type polyoma virus or by a mutant temperature sensitive for viral large tumor antigen function (ts-a). Elevated SCE frequencies were observed in two wild-type transformed cell lines growing at 37 degrees and in four ts-a-transformed lines upon growth at the permissive temperature for large viral tumor antigen (33 degrees). The increase in SCE frequency in ts-a-transformed cells at 33 degrees was reversed by growth at 39 degrees (nonpermissive for T-antigen function). An increase in SCE at 33 degrees was not observed in untransformed cells or in a ts-a-transformed cell line which makes a defective large viral tumor antigen. These results suggest that large viral tumor antigen can induce SCEs. Since large viral tumor antigen is also responsible for amplification of integrated viral DNA sequences (4), we tried to correlate this phenomenon with the increased SCE frequency. However, increasing SCE artificially by growing cells in the presence of 12-O-tetradecanoylphorbol-13-acetate did not result in amplification of integrated viral DNA in the absence of large viral tumor antigen function. Thus, there is no simple causal relationship between increased SCE and amplification.

Mammary tumor virus DNA as a marker for genotypic variance within hormone-responsive GR mouse mammary tumors

Mammary tumors of GR mice acquire extra mammary tumor virus (MMTV) DNA information within their DNA during tumor growth and development. These extra MMTV genes have been used by us as genotypic markers to investigate the heterogeneity of GR mammary tumors and their loss of hormone dependence during serial transplantation. Our studies reveal that the various subpopulations of cells within individual GR mammary tumors are characterized by differences in number and location of acquired extra MMTV DNA fragments. Losses of certain of these extra MMTV DNA fragments occur when mammary tumors become hormone independent, indicating a loss of hormone-dependent cells. The study of MMTV DNA markers also reveals that low levels of autonomous cells are already present in some hormone-dependent mammary tumors at an early stage of their development. The genotypic analysis strongly indicates that mammary tumor progression is not due to phenotypic adaptation but to clonal selection of the more aggressive sublines.

Correlation between the loss of the transformed phenotype and an increase in superoxide dismutase activity in a revertant subclone of sarcoma virus-infected mammalian cells

We have studied the effects of paraquat (methyl viologen), a herbicide that increases intracellular production of superoxide radical, on the viability of virus-transformed and nontransformed normal rat kidney (NRK) cells in culture. We have shown that a low concentration of paraquat (12.5 microM) is cytotoxic toward virus-transformed cell lines, including Kirsten sarcoma virus- and SV40-transformed NRK cells. The corresponding untransformed NRK cells were resistant to the same and a 4-fold higher concentration of paraquat. There was a good correlation between the susceptibility of transformed and untransformed cells to paraquat cytotoxicity and their ability to increase the superoxide dismutase (SOD) enzymatic activity. We found that paraquat is cytotoxic toward Kirsten sarcoma virus-transformed and SV40-transformed NRK cells which showed low intracellular SOD activity. The relationship between SOD activity and paraquat cytoxicity was strengthened by the finding that the tolerance of NRK cells to the drug was associated with high intracellular SOD activity. This report also describes the isolation of a revertant (revertant RE8G3) cell line derived from Kirsten sarcoma virus-transformed NRK cells after paraquat treatment which contains SOD activity at levels much higher than those found in NRK cells. This revertant is undistinguishable from NRK cells with respect to its lack of transformed cell properties. Not only are these cells normal morphologically but also they do not grow in soft agar, an in vitro property that closely correlates with in vivo tumorigenicity. Several biological and biochemical properties of RE8G3 cells, including growth characteristics, surface receptors for both transferrin and epidermal growth factor (EGF), and the EGF-dependent 32P phosphorylation of specific membrane polypeptides have been studied. The most interesting conclusion that can be drawn from these studies is that there is a correlation between loss of the transformed phenotype and an increase in both EGF receptors and EGF-dependent 32P phosphorylation of a m.w. 170,000 membrane-associated protein.

Papillomavirus infection of the cervix I. Correlation of histology with viral structural antigens and DNA sequences

Eight cervical biopsies showing mild dysplasia and one showing squamous metaplasia were studied for the presence of papillomavirus (PV) antigens using an immunoperoxidase method having immunospecificity against the genus-specific (common) structural antigen(s) and for PV-specific DNA sequences by molecular hybridization under nonstrigent conditions. Of the eight cases showing mild dysplasia, both PV antigens and PV DNA sequences were detected in five, PV antigens only in one, and PV DNA sequences only in one; viral antigens and DNA sequences were not detected in the remaining lesion. A characteristic cellular atypia (PV-induced atypia) was present in the superficial and intermediate layers of the epithelium in the six cases positive for viral antigens, and a proliferation of basal and parabasal cells (PV-induced hyperplasia) occurred in five of these. PV structural antigens were localized within nuclei of some of the cells displaying atypia but not in the proliferating cells. The PV-specific DNA sequences in all six cases had the properties of unintegrated PV-DNA. In view of the demonstration of both PV antigens and DNA sequences in this distinctive lesion (PV-induced atypia and/or hyperplasia), traditionally regarded as a form of dysplasia, it is proposed that this lesion be referred to as "papillomavirus infection of the cervix."

Human papillomavirus (HPV) in condylomatous lesions of cervix

Ninety-seven cervical condylomata classified histologically as flat condyloma (planum), papillary condyloma (acuminatum), and endophytic condyloma were studied by transmission electron microscopy (TEM) and by immunoperoxidase technique (IPT) for the presence of human papillomavirus (HPV) particles and antigen, respectively. Both techniques localized HPV chiefly in nuclei of koilocytotic cells. HPV particles were found in 25% of the cases by TEM and HPV antigen was detected in 48% of the cases by IPT. All cases positive by TEM were also positive by IPT, thus confirming the specificity of the immunological staining. The viral antigen was detected in 56% of 68 flat condylomata, 35% of 26 papillary condylomata, and in none of 3 cases of endophytic condylomata. However, when histiotypes of virus-positive condylomata were controlled for the intraepithelial extent of koilcytotic cells, the prevalence of HPV correlated with the extent of koilocytosis rather than with the histiotype. The immunologic technique will be of value for the further characterization of cervical condylomata and of the relationship between HPV infection and cervical intraepithelial neoplasia.

Feline uveal melanoma model induced with feline sarcoma virus

This paper described the first animal model of a virally induced uveal melanoma. Tumors developed following the injection of an RNA tumor virus, i.e., Gardner strain feline sarcoma virus, into the anterior chamber of newborn kittens. Histologically, the tumors were found to be iris and ciliary body melanomas, many of which showed invasion. The histology and ultrastructure of those tumors are described.

Characteristics of osteogenic sarcoma of hamsters induced by BK virus

Two out of 9 weanling hamsters, treated with intravenous inoculation of highly concentrated human papovavirus BK, propagated in human embryonic kidney cells, developed osteogenic sarcomas of the costal cage and the mandibula. The sera of the tumor-bearing animals were positive for BK T-antigen and the successively transplanted tumors were positive for intranuclear T-antigen when tested with anti-SV40 T-antibody by immunofluorescence. The tumor tissue exhibited various stages of maturation, from areas showing immature sarcoma and angiomatous sarcoma to those of well-differentiated osteogenic sarcoma. Tumor histology was described in detail.

Electron microscopic features of a brain tumor induced in hamster by BK virus, a human papova virus

In order to locate the target cells for malignant transformation by BK virus (a human papova virus) in hamster brain, electron microscopic observation of tumor originally induced in hamster brain by BK virus was performed. With light microscopy, the BK virus-induced tumor (Vn 17) bore a close resemblance to human malignant ependymoma. Under the electron microscope, numerous microvilli and few cilia were visible on the surface of the tumor cells. These tumor cells were joined to each other by desmosomes. Gap junctions were not observed. Multilayered cuboidal cells were observed around the lumen and blood vessels in the tumor. With regard to fine structure, three types of Vn 17 cells were recognized; ependymal like cells, tanycytes with prominent cell processes, and undifferentiated cells with few cytoplasmic organelles. There was no basal lamina between the ependymal cells and the connective tissue stroma. The Vn 17 cells showed some similarity to the ultrastructural features of the epemdymal cells of newborn rabbits, suggesting that the target cells for Vn 17 may be cells related to ependyma. Malignant transformation of the cells would be initiated in the early stages after BK virus inoculation into the brain of newborn hamsters.

Uropod-bearing lymphocytes (hand mirror cells) in a virus-induced murine lymphoma

A Moloney murine leukemia virus-induced T-cell preleukemic thymic lymphoma tissue culture from an inbred C3H/HeJ mouse contained numerous hand mirror cells (HMC). The cells were studied by light and phase-contrast microscopy, special stains, indirect immunofluorescence for terminal deoxynucleotidyl transferase, and scanning and transmission electron microscopy. The uropods of the mouse and human HMC were similar. In contrast, viruses were noted on the tip of the mouse HMC uropod by transmission electron microscopy. These observations, reported for the first time in an animal model, will enable investigators to study the HMC under controlled conditions.

Histology and ultrastructural aspects of virus-induced primary liver cancer and transplantable hepatomas of viral origin in chickens

The macroscopic, light microscopic and electron microscopic features and biological properties of MC-29 virus-induced hepatocellular carcinomas in chickens are described. The tumors developed in noncirrhotic livers within a very short time and formed metastases. Virus production was also evidenced in the tumors. There were also indications of virus production in the transplantable tumors. The tumors grew equally well after sc, ip, or im inoculation. In about 25% of the tumor-bearing animals, tumorous nodules developed in the liver. It could not be established whether they were metastases or primary liver cancers induced by viruses released from the transplantable tumors.

Virus-induced papillomas of the alimentary tract of cattle

An abattoir survey was carried out to determine the incidence and aetiology of squamous papillomas of the alimentary tract of cattle in Scotland and North England as they were suspected of being involved in the genesis of alimentary carcinoma in certain localized geographical areas. A total of 7,746 cattle of a wide age range was examined. Various subsets of this number were subjected to analyses of certain specific factors. The calculated overall incidence was 19% and the detailed site incidence and tumour multiplicity are given. The sites at which papillomas were found were identical with those at which carcinoma had been noted in animals from a high-cancer area. The number of sites affected by papilloma and the tumour multiplicity were much lower in the general population than in the high-cancer area. Inclusion bodies, identified by electronmicroscopy as virus, were found in tumour cell nuclei and a typical papilloma virus was purified from the tumours. The structure of the tumours is described and the possible plurality of bovine papilloma-viruses is discussed in the light of recent findings in the human viruses. The general interest of a naturally occurring and geographically localized oncogenic system, in which an environmental carcinogen and a virus might be involved, is extended.

Electron microscopic studies of intracisternal virus particles in Soehner-Dmochowski murine sarcoma virus-induced bone tumors of New Zealand Black rats

Soehner-Dmochowski murine sarcoma virus (Moloney)-induced bone tumors of New Zealand Black rats carry two morphologically different types of virus particles, namely, extracellular type C and intracisternal virus particles, which have thus far not been reported. These two types of virus particles have also been observed in the tissue culture cells derived from normal prostate tissues of A/Dm and BALB/c/Dm mice after inoculation of cell-free extracts of these bone tumors. The intracisternal virus particles, 90 to 120 nm in diameter, have always been found in the rough endoplasmic reticulum; they have two inner concentric layers with a relatively electron-lucent center, frequently showing cylindrical, chain-like, or multipolar budding forms. Type C virus particles produced by Soehner-Dmochowski murine sarcoma virus (Moloney)-infected prostate tissue culture cells from A/Dm and BALB/c/Dm mice belong to the murine sarcoma-murine leukemia virus group, as revealed by the fixed immunofluorescence test and by immunoelectron microscopy. The morphological and immunological relationship of intracisternal virus particles and other types of virus particles (such as type C, type H, and intracisternal type A virus particles) and intracisternal virus particles in guinea pig leukemia are defined by routine electron microscopy observations and by immunoelectron microscopy studies.