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Biomedical subjects

M F Evans

Publications and source records attributed to M F Evans.

84 records · Page 5Linked to original sources
PubMed1992

Screening for high- and low-risk human papillomavirus types in single routine cervical smears by non-isotopic in situ hybridization.

Routine cervical smears (n = 262) from a Sexually Transmitted Diseases clinic were screened by non-isotopic in situ hybridization (NISH) stratifying human papillomavirus (HPV) infections into HPV6/11 (low risk) and HPV16/18/33 (high risk) categories. Of 188 patients with cytologically normal smears, HPV sequences were demonstrated in 41%. Of the 128 cases analysed by dual NISH, 16% contained low risk, 20% high risk and 5% both groups. In patients with cytological evidence of wart virus infection (WVI) only, 54% (n = 50) contained high-risk and 22% low-risk HPV types. The comparable incidences in CIN1/2 plus WVI (n = 24) were not significantly different: 54% and 17%, respectively. Cytological criteria underestimate the prevalence of HPV infection in patients with cytologically normal smears. This represents either 'occult' or 'latent' infection. The identical prevalence of HPVB16/18/33 in WVI only, and CIN1/2 plus WVI, suggests that the cytopathic effect induced by these HPVs may represent one end of a spectrum of morphological change which progresses to cervical intraepithelial neoplasia (CIN).

DNA Probes, HPV↗
PubMed1992

Integration of human papillomavirus types 16 and 18 in cervical adenocarcinoma.

AIMS: To determine which type of human papillomavirus (HPV) is associated with cervical adenocarcinoma and whether the virus was integrated or episomal in two continents. METHODS: Biopsy specimens from the UK (n = 16) and South Africa (n = 22) were analysed by non-isotopic in situ hybridisation (NISH) for HPV types 6, 11, 16, 18, 31, 33, and 35 on archival biopsy specimens using digoxigenin labelled probes. RESULTS: A total of 20 adenocarcinomas (53%) from both groups contained HPV DNA. In the UK group, seven and four cases contained HPV 18 (44%) and 16 (25%) respectively. In the South African group, nine cases contained HPV 18 (41%) while HPV DNA was not detectable in the other 13 cases. Hence HPV 18 was present in 80% of HPV positive adenocarcinomas. CONCLUSIONS: The HPV 16 or 18 genome was integrated in all viral positive cases. In two cases HPV 18 was also present in an episomal form. These data indicate that HPV integration is common to cervical adenocarcinoma in two continents by the same methodology. The lower prevalence of HPV 18 detection in the South African group may have been due to the presence of other or unsequenced HPV types.

Adenocarcinoma↗
PubMed1992

Detection of high risk human papillomavirus in routine cervical smears: strategy for screening.

AIM: To develop a methodology for direct detection of high risk human papillomavirus (HPV) infection in routine cervical smears by non-isotopic in situ hybridisation (NISH) which can be compared with cytopathological assessment of the same cells. METHODS: The methodology was established using cultured cells and routine cervical smears hybridised with digoxigenin labelled probes for HPV, 16, 18, 31, and 33. The technique was applied to the analysis of 53 patients from a sexually transmitted disease clinic. RESULTS: The optimal sensitivity achieved for single HPV detection in cultured cells was 1-2 copies of HPV 16 per cell and that for detection of a cocktail of HPV types in routine cervical smears was 2.5-12 copies per cell. Of parallel smears taken from patients with a normal Papinacolau-stained smear 33.3% (24) contained a HPV 16, 18, 31, and 33 signal indicating an occult HPV infection. The prevalence of these HPV types was similar in women in whom a cytopathological diagnosis of wart virus infection was made (64.7%, 17) and in patients with mild dyskaryosis (75%, 12). CONCLUSIONS: The methodology evolved localises HPV sequences directly to epithelial cell nuclei, which can be morphologically assessed by haematoxylin counterstaining. Sample contamination with exogenous viral sequences can be distinguished from true infection. In this study, a HPV signal was not found in morphologically normal epithelial cells. The methods described will permit the detection of HPV sequences in routinely collected cervical smears and the evaluation of the natural history and potential clinical relevance of HPV infection without changes in clinical practice.

Cells, Cultured↗
PubMed1991

Episomal and integrated human papillomavirus in cervical neoplasia shown by non-isotopic in situ hybridisation.

It was postulated that non-isotopic in situ hybridisation (NISH) signal types 1-3 for human papillomavirus in cervical biopsy specimens represent episomal or integrated virus. The aim of this study was to validate this hypothesis by independent molecular techniques. Fresh cervical intraepithelial neoplasia (CIN) and squamous cell cancer (SCC) tissue were examined for NISH signal pattern by hybridising with digoxigenin labelled HPV 16. DNA was extracted from the same samples and analysed by restriction endonuclease digestion and Southern blotting to determine the physical state of the viral genome. Six CIN biopsy specimens showed a type 1 NISH signal for HPV 16. On Southern analysis these biopsy specimens contained only episomal HPV 16. Three SCC with a type 2 NISH signal contained integrated HPV 16 by Southern analysis. Two specimens, a CIN 3 and an SCC with a type 3 NISH signal for HPV 16, showed the presence of both episomal and integrated HPV 16 with conventional Southern analysis and two dimensional gel electrophoresis. These results show that episomal HPV can be reliably determined by NISH type 1 signal, integrated HPV by type 2, and a combination of both episomal and integrated HPV, by a type 3 signal in archival paraffin wax embedded cervical biopsy specimens. This will add another variable to the epidemiological studies of HPV infection. In particular, it will now allow retrospective studies to be done to define the role of episomal and integrated HPV in the evolution of cervical intraepithelial neoplasia and other cervical disease associated with this virus.

Blotting, Southern↗
PubMed1991

In situ human papillomavirus (HPV) genotyping of cervical intraepithelial neoplasia in South African and British patients: evidence for putative HPV integration in vivo.

In South Africa asymptomatic wart virus infection diagnosed by morphological criteria occurs in 16-20% of all ethnic groups; the incidence in black women is 66%. To identify human papillomavirus (HPV) types the prevalence of HPV in cervical intraepithelial neoplasia (CIN) in South African women (n = 72) with age matched British women (n = 73) was compared by non-isotopic in situ hybridisation (NISH) using digoxigenin labelled probes for HPV 6, 11, 16, 18, 31, 33 and 35 on archival biopsy specimens. A higher proportion of British biopsy specimens (68%) contained HPV than those from South Africa (50%) in CIN 2 and 3; this difference was due to HPV 16. Thirty six per cent of the positive biopsy specimens from South African women also contained HPV 33/35 compared with 16% in the United Kingdom. There was no difference in HPV detection with age in either group. These data indicate that HPV types vary geographically, with "minor" HPV types being more common in South Africa. Three qualitatively distinct NISH signals were observed; a diffuse (type 1) signal in superficial cells, mainly koilocytes; a punctate signal (type 2) in basal/"undifferentiated" cells in CIN 3; and combined type 1 and 2 signals in CIN with wart virus infection (type 3). The punctate signal may represent HPV integration.

Adolescent↗
PubMed1991

In situ evidence for HPV 16, 18, 33 integration in cervical squamous cell cancer in Britain and South Africa.

In a previous study three types of HPV signal were described in CIN. It was suggested that a type 1 signal represented episomal HPV while a type 2 signal represented integrated HPV; and a type 3 signal was indicative of both episomal and integrated HPV. To test this hypothesis 91 squamous cell cancers (SCC) of the cervix from Britain and South Africa were examined for HPV 6, 11, 16, 18, 31, 33, 35. Of the South African group (n = 69) 64% contained HPV types 16 (n = 29) and 18 (n = 15). The SCC in the British group (n = 22) contained HPV 16 and HPV 33 in 12 and three cases, respectively. Of the HPV positive biopsy specimens, 86% showed a type 2 signal in keratinising and non-keratinising tumours and the remainder a type 3 signal. Type 3 signal was present only in keratinising tumours. The presence of punctate signal in 100% of HPV containing SCC, together with localisation of HPV signal to sister chromatids in tumour cell mitotic figures in vivo, provides further evidence for type 2, and the punctate component of type 3 signal representing viral integration.

Age Factors↗
PubMed1990

Human papillomaviruses in anogenital warts in children: typing by in situ hybridisation.

OBJECTIVE: To identify the types of human papillomaviruses found in anogenital warts in children and to relate these to clinical and social information. DESIGN: In situ hybridisation using biotin labelled DNA probes to 11 types of human papillomavirus was performed on biopsy specimens from 17 children with anogenital warts. SETTING: Nuffield department of pathology and the department of dermatology, Oxford. PATIENTS: Children in one group were referred by general practitioners or paediatricians to the dermatology department, where biopsies were performed. The other children were seen in four different hospitals, and biopsy specimens were submitted to the laboratory at the physician's or pathologist's request. RESULTS: Of the 17 biopsy specimens, 10 contained cells positive with a probe to a genital human papillomavirus type (types 6 or 11), while six were positive with a skin virus type (types 2 or 3). One was negative. The virus type present bore no relation to the site or appearance of the warts. The virus type did, however, appear to correlate with groups of children. Skin types were commoner in older children (over 4 years), in those with a relative who had skin warts, and in children with warts elsewhere; there was no relation with the child's sex and no suspicion of sexual abuse in these children. These circumstances suggested non-sexual transmission, such as autoinoculation. In contrast, genital types were commoner in girls, in children under 3 years, in children with relatives with genital warts, and in those with no warts elsewhere. Nevertheless, there was suspicion or evidence of sexual abuse in only half these children, suggesting that other routes of transmission--for example, perinatal--might have been implicated. CONCLUSION: Anogenital warts in children may contain either skin or genital wart virus type. Although the type of human papillomavirus present may give some indication of the likely mode of transmission, this can be interpreted only in conjunction with all available clinical and social information. The type of virus does not provide proof of the presence or absence of sexual transmission.

Anus Diseases↗
PubMed1989

The ras oncogene and tumour metastasis: observations on murine cells transfected with activated human c-Ha-ras.

Transfection of cells with cloned genes or total genomic DNA offers a means for studying aspects of neoplastic behaviour. We have used this method to examine whether incorporation of the cloned 6.6-kilobase (kb) fragment of DNA containing the mutant c-Ha-ras human oncogene can confer metastatic capability on murine NIH 3T3 cells. Cells co-transfected with the mutated ras gene and the neomycin resistance marker pSV2neo were selected by culture in neomycin. On subcutaneous inoculation into MF 1 nude mice, these cells proved to be tumourigenic with short latent periods (approximately 14 days)--nude mice were used to circumvent immunological rejection of the mouse cells expressing the product of the human oncogene. Transfectants were capable of lung colonisation after intravenous injection, but there was no evidence of spontaneous metastasis at autopsy, or on histological examination of the lungs and other organs, 90 days after inoculation. Incorporation of the transfected oncogene was confirmed by Southern blotting and its expression by dot-blot hybridisation and immunoprecipitation. The results in this experimental system indicate that transfection of a mutated human ras oncogene into non-neoplastic 3T3 cells can confer part of the metastatic phenotype, namely lung colonisation, but is not by itself sufficient to induce spontaneous metastatic behaviour.

Animals↗
PubMed1988

Parvovirus as a cause of hydrops fetalis: detection by in situ DNA hybridisation.

Lung tissue from 13 cases of unexplained non-immunological hydrops fetalis was examined by in situ hybridisation to detect parvovirus. Four specimens contained parvovirus DNA in cells in the blood vessel lumina and alveoli. Twenty six control cases were negative for parvovirus DNA. As there was no known epidemic of parvovirus infection during the study period, this suggests that parvovirus is a relatively common cause of non-immunological hydrops fetalis. In situ hybridisation may have a role in clinical medicine, particularly for retrospective investigations.

DNA, Viral↗
PubMed1987

Detection of low copy human papilloma virus DNA and mRNA in routine paraffin sections of cervix by non-isotopic in situ hybridisation.

In analysing human papilloma virus (HPV) infection of the cervix in formalin fixed paraffin sections by non-isotopic in situ hybridisation two main problems were found: detachment of sections from the glass during hybridisation and probe detection; inadequate sensitivity and inability to assess sensitivity of the in situ procedure. The first problem was investigated by assessing the efficiency of various tissue adhesives individually and in combination. The second problem was addressed by optimising conditions for DNA unmasking, hybridisation, and biotinylated probe detection. Sensitivity of the final in situ procedure developed was assessed by using the detection of pHY2.1 repeats as a built-in control. Extrapolation of data showed that less than 10 copies of HPV DNA can be visualised by these procedures. HPV nucleic acid, mainly in the form of DNA, was detected not only in koilocytic nuclei but also in suprabasal cells in condylomas and CIN lesions. HPV mRNA was also visualised in the cytoplasm (and probably also nuclei) of the same cell types. These non-isotopic in situ procedures give results comparable to those obtained with radiolabelled probes, but they are less time consuming and provide better morphological resolution.

Cervix Uteri↗
PubMedDate not supplied

Common association of HPV 2 with anogenital warts in prepubertal children.

Anogenital (AG) warts in 31 prepubertal children were HPV typed by nonisotopic in situ hybridization (NISH) using digoxigenin-labeled probes for human papilloma virus (HPV) types 1-5, 6, 11, 16, 18, 31, and 33. Mode of transmission was determined from historical, clinical, and laboratory data independent of HPV typing. HPV 2 was detected most commonly (13/31 warts) followed by HPV 6 (7/31), HPV 11 (5/31), and HPV 16 (1/31). Although not reaching statistical significance, our results suggested that a mucosal HPV type (6, 11, 16) in a child's AG warts implied transmission from mucosal warts and conversely cutaneous HPV 2 transmission from warts at a cutaneous site. HPV typing provided no helpful information regarding actual mode of transmission of AG warts in these children. The high prevalence of HPV 2 in children's AG warts and the low prevalence of sexual abuse (2 of 31 children) found in this study suggest innocent auto- or heteroinoculation from cutaneous warts may be a common means by which children acquire AG warts.

Anus Diseases↗