Human papillomavirus type 18 is associated with less apoptosis in fibroblast tumours than human papillomavirus type 16.

In human cervical neoplasia human papillomavirus (HPV) type 18 has a higher cancer/cervical intraepithelial neoplasia (CIN) prevalence ratio than HPV 16. Fibrosarcomas derived from rat fibroblasts transfected with HPV 16 or 18 genomes showed increased apoptosis compared with controls. However, HPV 18 was associated with significantly less apoptosis than HPV 16, affording one possible explanation for the more rapidly progressive cervical neoplasia associated with HPV 18.

Induction of apoptosis in NIH3T3 cells after serum deprivation by overexpression of rho-p21, a GTPase protein of the ras superfamily.

Oncogenes appear to influence apoptosis in two ways. Some activate cells from a growth-arrested state to one in which both apoptosis and entry to S-phase become possible, the choice between them being determined by a second signal, such as cytokine or growth factor. Cells in this state are often sensitive to apoptosis induced by a wide variety of agents, including several drugs used in cancer chemotherapy.

Increasing the susceptibility of the rat 208F fibroblast cell line to radiation-induced apoptosis does not alter its clonogenic survival dose-response.

Recent studies have suggested a correlation between the rate and incidence of apoptosis and the radiation response of particular cell lines. However, we found that increasing the rate of induction of apoptosis in the fibroblast line 208F, by transfecting it with human c-myc, did not lead to a change in its clonogenic survival dose-response for either gamma-irradiation or 125I-induced DNA damage. It was also found that expression of mutant (T24) Ha-ras in the 208F line appeared to decrease the level of apoptosis per mitosis after irradiation and inhibited the formation of nucleosomal ladders, but did not affect either the onset of the morphological features of apoptosis or the clonogenic survival dose-response of the cells to either gamma-irradiation or 125I-induced DNA damage.

Accumulation of p53 is associated with tumour progression in cutaneous lesions of renal allograft recipients.

Renal allograft recipients suffer from a markedly increased susceptibility to premalignant and malignant cutaneous lesions. Although various aetiological factors have been implicated, little is known of the associated genetic events. In this study we initially employed immunocytochemical techniques to investigate the prevalence and localisation of accumulated p53 in over 200 cutaneous biopsies (including 56 squamous cell carcinomas) from renal allograft recipients and immunocompetent controls.

Apoptosis is inversely related to necrosis and determines net growth in tumors bearing constitutively expressed myc, ras, and HPV oncogenes.

Immortalized rat fibroblasts were transfected with expression plasmids containing a mutated human Ha-ras (T24) oncogene, human c-myc, HPV 16 or 18 genomes, or combinations of these. Cell proliferation rates in vitro of the resulting 13 transformed lines were closely similar but apoptotic rates in vitro varied over a 60-fold range and correlated inversely with rates of population expansion in culture. To determine whether such differences in susceptibility to apoptosis affected the pattern of tumor growth in vivo, the transfected lines were injected subcutaneously into immunesuppressed mice producing fibrosarcomas in which prevalence of apoptosis and mitosis, extent of necrosis, and net growth rate were measured.

Prevalence of human papillomavirus DNA in cutaneous neoplasms from renal allograft recipients supports a possible viral role in tumour promotion.

It is well established that renal allograft recipients (RARs) have an increased incidence of viral warts and premalignant and malignant cutaneous lesions, and the risk of their development increases in proportion to duration of graft survival. It has been postulated that, in addition to the effects of prolonged immunosuppression and previous sun exposure, human papillomaviruses (HPV) may also contribute to the carcinogenic process. In this study, the prevalence of HPV DNA was examined in a range of premalignant and malignant cutaneous tumours from 50 immunosuppressed patients (47 renal allograft recipients plus three cardiac allograft recipients) and 56 immunocompetent patients using Southern hybridisation as a low-stringency screening method and type-specific polymerase chain reaction (PCR) assays for eight HPV types.

Susceptibility to apoptosis is differentially regulated by c-myc and mutated Ha-ras oncogenes and is associated with endonuclease availability.

Oncogenes and oncosuppressors can deregulate cell replication in tumours, and recently have been shown to influence the probability of apoptosis. The effects of human c-myc and mutated (T24) Ha-ras oncogenes on susceptibility to apoptosis were investigated by introducing them into immortalised rat fibroblasts. The resulting family of transfectants showed closely similar measures of proliferation, but widely divergent rates of apoptosis, differing by up to fifteen-fold, that correlated inversely with population expansion rates in vitro.

PCR analysis of the upstream regulatory region of human papillomavirus genomes in cervical intraepithelial neoplasia and cervical carcinoma.

Aims: To test whether human papillomavirus (HPV) variants with large scale sequence alterations to the upstream regulatory region are present in cervical intraepithelial neoplasias (CIN) and cervical carcinomas.

Methods: New PCR based assays were designed specifically to detect large scale insertion/deletion alterations in the upstream regulatory region of HPV 16 and 18. The assays were applied to 24 cases of CIN and 34 cases of cervical carcinoma previously shown to contain these two high risk HPV types.

Development of parenchymal abdominal organ models for use in teaching veterinary soft tissue surgery.

Models of the canine spleen, kidney, and liver were made from soft plastic to simulate the organs of the live animal as closely as possible in appearance and tissue handling properties. Each organ model was independently evaluated by five small animal surgeons who performed several common surgical procedures on each model. All models had a realistic appearance and, with the exception of one tissue handling problem with the kidney model, and one with the liver model, tissue handling properties of the models were comparable to those of the organs in the live animal.

A PCR approach to discriminate between integrated and episomal HPV DNA in small clinical specimens.

HPV infection has long been implicated in the development of cervical carcinoma. There is strong evidence for association of high-risk HPV types 16 and 18 with cervical intraepithelial neoplasia (CIN) grades 2 and 3, and integration of viral DNA of these types into the host genome has been suggested to play an important role in progression to invasive cervical carcinoma. However, the existing techniques for detection of integrated DNA in clinical specimens are time-consuming and require large amounts of template DNA, often unavailable for small premalignant CIN lesions.

Human papillomavirus type 18 associates with more advanced cervical neoplasia than human papillomavirus type 16.

A type-specific, sensitive, polymerase chain reaction-based assay for human papillomavirus (HPV) types 6b, 11, 16, 18, and 33 was applied to 47 cervical carcinomas, 60 cases of cervical intraepithelial neoplasia (CIN), and 24 samples of histologically normal cervix. As expected, the combined incidence of the common high-risk genital HPVs (types 16 and 18) was high in carcinomas (79%) and CIN 2/3 (60%), low in CIN 1 (25%), and nonexistent in the normal controls. Analysis of the data by viral type and pathology revealed statistically significant differences that consistently pointed to an association of HPV 18 with more advanced disease than HPV 16.

The apoptosis endonuclease and its regulation.

Activation of an endogenous endonuclease has been observed in conjunction with the structural changes of apoptosis in a wide variety of cell types and circumstances. The endonuclease is present constitutively in some cells (e.g.

Recombinant DNA technology and its diagnostic applications.

As yet recombinant DNA technology does not appear to have widespread diagnostic application in pathology. However, it does have a useful role to play in specific circumstances in at least three main areas: a it can provide precise diagnostic information about genetic diseases, allowing appropriate counselling, and indicating future directions for research on therapeutic intervention, e.g.

HPV in full thickness cervical biopsies: high prevalence in CIN 2 and CIN 3 detected by a sensitive PCR method.

A new type-specific, sensitive, non-radioactive assay is described for the detection of human papillomavirus (HPV) DNA in tissues. Sequences within the E6 gene were amplified by the polymerase chain reaction (PCR), using primer pairs which clearly distinguish HPV types, including those with close sequence homology such as 6b and 11. The amplified DNA products were identified by non-radioactive oligonucleotide hybridization and restriction endonuclease mapping, and the method was sufficiently sensitive to detect between 3 and 5 SiHa cells (each containing 1-2 copies of HPV 16 DNA) amongst 10,000 non-HPV-containing cells.

Antiperinuclear factor, a marker autoantibody for rheumatoid arthritis: colocalisation of the perinuclear factor and profilaggrin.

The antiperinuclear factor, an autoantibody specific for rheumatoid arthritis, was found in 51/63 (81%) patients with rheumatoid arthritis by indirect immunofluorescence on human buccal mucosa cells. The sensitivity of the antiperinuclear factor test was increased by pretreating the buccal mucosa cells with 0.5% Triton-X100.

Experimental autoimmune retinitis in the rat induced by immunization with rhodopsin: an ultrastructural study.

Experimental autoimmune retinitis induced by immunization with rhodopsin was investigated in the Lewis rat using transmission electron microscopy and light microscopy. The first signs of retinitis consisted of scattered infiltrations of lymphocytes and other mononuclear cells, predominantly in the inner nuclear layer and outer plexiform layer. Occasionally, some macrophages were detected in the photoreceptor cell layer.

Sensitivity of digoxigenin and biotin labelled probes for detection of human papillomavirus by in situ hybridisation.

The sensitivity of digoxigenin and biotin labelled DNA probes for the detection of human papillomavirus (HPV) by dot blotting and in situ hybridisation was compared in tissues from cervical, laryngeal, and anogenital neoplasia. Probes were either labelled with digoxigenin by the random primer technique and detected with anti-digoxigenin antibody, or labelled with biotin by nick translation and detected with streptavidin, both methods having a common final visualisation procedure using alkaline phosphatase. Digoxigenin labelled probes proved two to 10-fold more sensitive by quantitative dot blotting and four-fold more sensitive in detecting HPV 16 DNA in a series of 31 anal carcinomas, compared with biotinylated probes.

Apoptosis. The role of the endonuclease.

Cell death by apoptosis mediates several important physiologic and pathologic processes and appears to be intrinsically programmed. Its characteristic features are distinctive morphologic changes of nucleus and cytoplasm, along with cleavage of chromatin at regularly spaced sites. Here we study DNA organization and nuclear structure in apoptotic thymocytes to define the cleavage event and, by implication, the role of the responsible endonuclease.

Novel histopathologic findings in a surviving case of hemolytic uremic syndrome after bone marrow transplantation.

We report novel renal histopathologic features in a patient with hemolytic uremic syndrome after allogeneic bone marrow transplantation who survived with plasma exchange therapy. This distribution of vascular lesions within the kidney differed from previously described cases, which were uniformly fatal, in that there were marked arterial changes in addition to arteriolar and glomerular microangiopathy. A high rate of frequency of apoptotic cells within glomeruli was found.