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Biomedical subjects

M Norval

Publications and source records attributed to M Norval.

At least 145 records · Page 8Linked to original sources
PubMed1984

Natural killer cell activity in patients with abnormalities of the uterine cervix.

Peripheral blood lymphocytes from 105 patients with various degrees of cervical dysplasia (normal/mild, moderate and severe) up to carcinoma in situ were assayed for natural killer cell activity against K562 cells and Chang liver cells in vitro. No difference was found between the natural killer cell activities of any of the groups of patients studied. In addition, the K cell activity of the patients' lymphocytes was assayed in an antibody-dependent cellular cytotoxicity assay on Chang liver cells with anti-Chang cell antiserum. No difference was found between patient groups. There was no correlation between the presence of antibodies in the patients' serum to cytomegalovirus measured by anti-complement immunofluorescence and increased natural killer cell activity.

Age Factors↗
PubMed1983

On the nature of the deep cellular disturbances in human-papilloma-virus infection of the squamous cervical epithelium.

In the squamous epithelium of the cervix, disturbed deep cells, usually regarded as dysplastic, often underlie superficial koilocytes. Recognition of koilocytosis as a cytopathic effect of human papilloma virus (HPV) prompts reconsideration of the state of the deep cells, which could be non-dysplastic or dysplastic. In the dysplastic states HPV could be non-causative or causative. For dysplastic causation by HPV, a cell-differentiation hypothesis reconciles the coexistence in the epithelium of a permissive HPV infection of the superficial layers (koilocytosis) and a non-permissive cellular infection of the deep layers, which may undergo transformation to dysplasia.

Animals↗
PubMed1983

Comparison of cytotoxicity and thin-layer chromatography methods for detection of mycotoxins.

Thirty-three standard mycotoxins were assayed by thin-layer chromatography and by cytotoxicity in HEp-2 and Chang cells. Various levels of detection were found. The cytotoxicity test was significantly more sensitive than thin-layer chromatography for the trichothecenes and should be useful for screening extracts from animal feedstuffs for the presence of unknown mycotoxins.

Biological Assay↗
PubMed1982

Association of toxin-producing fungi with disease in broilers.

An episode of suboptimal growth, poor feathering and behavioural abnormalities in broilers in Scotland during the winter of 1980-81 is described. This was considered to be associated with mould-contaminated maize and wheat components of the feed, from which fusaria were isolated in persistently high numbers. Four species, Fusarium culmorum, F tricinctum, F nivale and F moniliforme, were identified. Chloroform extracts of the raw materials and of an artificial medium in which three of the Fusarium species were cultured proved toxic to tissue cultures of a human epithelial cell line (HEp II). Specific identification by thin layer chromatography of the mycotoxins deoxynivalenol, zearalenone and diacetoxyscirpenol was achieved in some extracts. In addition, several other areas of the chromatograms were found to be toxic in the HEp II cell system and these may contain toxins for which standards were not available or, alternatively, previously uncharacterised fungal metabolites. It was concluded that the toxins produced by the fusaria were major contributing factors to the disease symptoms shown by the birds.

Animal Feed↗
PubMed1982

Lack of association of cytomegalovirus with adenocarcinoma of the colon.

Tumor specimens from patients with adenocarcinoma of the colon or rectum were examined for the presence of cytomegalovirus (CMV), and specimens of normal mucosa from the same patients were studied in parallel. Frozen sections of 14 specimens were made and the presence of CMV mRNA assayed by in situ hybridisation using 3H-labelled CMV-DNA as a probe. Nine of these sections were also tested for cytomegalovirus antigens by immunofluorescence. No viral nucleic acids or antigens were detected. In addition to these direct approaches, the specimens were disaggregated and 19 were successfully cultured in various media over several months without yielding virus on any occasion. Areas containing epithelial cells were found in some cultures, foci of bipolar cells in others, while, in several, fibroblastic cells predominated. To ensure that any virus-containing cells were not lost by this method, the disaggregated tumour and normal intestinal cells were directly co-cultivated and also fused with human embryo lung cells, which are permissive for cytomegalovirus replication. The resulting cultures were examined over two to three months for the presence of cytomegalovirus, and in no instance was virus found, despite attempted induction by iododeoxyuridine. Two fusion cultures became contaminated with cytomegalovirus, strain AD-169, which was being handled in the laboratory at the same time. The strain was identified by the pattern of viral DNA fragments produced by restriction endonuclease cleavage. Thus the accidental passage of virus in the heterokaryons did not alter its DNA and would further indicate the absence of any cytomegalovirus genomes in the adenocarcinoma cells.

Adenocarcinoma↗
PubMed1982

Lack of association of cytomegalovirus antibody level with carcinoma of the uterine cervix.

Serum samples were collected from 199 patients attending a gynaecological clinic, colposcopy specimens being taken at the same time for routine pathology of paraffin sections which ranged from normal, through the degrees of dysplasia to carcinoma in situ. Other parameters noted were age, number of pregnancies and time since last pregnancy. When level of antibody to cytomegalovirus in each serum sample was tested by ELISA, anti-complement immunofluorescence and neutralisation, no correlation was found between antibody titre and pathological diagnosis. The only interdependence seen was that, as the age of the patients increased, so did the frequency of sero-positivity to cytomegalovirus. Also in the group studied the frequency of carcinoma in situ was not age dependent.

Adolescent↗
PubMed1981

Association of human cytomegalovirus (HCMV) with mink and rabbit lung cells.

The association of human cytomegalovirus with mink and rabbit lung cells was studied. Strain AD-169 was used which was free of Mycoplasma and other contaminating agents. It was found to be incapable of productively infecting mink lung cells. Infection appeared to be initiated but aborted at an early stage. This was indicated by indirect immunofluorescence, assays of culture supernatants and cell lysates for infectious virus, electron microscopy of ultra-thin sections of infected cells, labelling of virus and viral DNA with 3H-thymidine and assay of virally-induced DNA polymerase at various times after infection. On the other hand, using these methods. AD-169 was found to infect rabbit lung cells, the virus being produced in low amounts over a period of up to one month after infection. At this time, focal areas of infection were still apparent and 15 per cent of the cells expressed nuclear viral antigens as shown by immunofluorescence. The viral genome was assumed to have become latent in some rabbit cells with a few being capable of producing infectious virus.

Animals↗
PubMed1981

Growth in culture of adenocarcinoma cells from the small intestine of sheep.

Explant cultures were initiated from adenocarcinoma of the small intestine in sheep and from various metastases. Several cell types grew, most being fibroblastic in nature. However, 2 cultures yielded mixed cells which arranged themselves into areas of epithelial-like cells surrounded by fibroblast-like cells and this pattern was consistent over 30 subcultures and several months of culturing. The epithelial-like cells were separated from the others by the use of a modified medium containing citrulline or by sedimentation through a bovine serum albumin solution. Various properties, including their growth rate in 5% and 0.5% serum, the absence of surface fibronectin and their ability to grow in semi-solid agar, indicated that they may represent carcinoma cells. Screening for virus production from these cells and all other explant cultures proved negative.

Adenocarcinoma↗
PubMed1980

Search for viruses in rheumatoid macrophage-rich synovial cell populations.

The adherent cells remaining after short-term culture of synovial fluid and synovial membrane cells from rheumatoid and non-rheumatoid patients were examined for the presence of a productive virus infection and for various viral antigens. Labelling was carried out with 3H-thymidine and 3H-uridine followed by sucrose density gradient centrifugation of the culture supernatant. Only in 1 case was there incorporation of 3H-uridine into material of density 1 . 21 g/cm3. Viral antigens were tested for by indirect immunofluorescence with antisera to rubella virus, the retroviruses RD-114 and simian sarcoma associated virus, early adenovirus type 2 antigens, late adenovirus type 2 antigens, SV-40 T antigen, and in 1 case measles virus. No cell showed immunofluorescence with any antiserum except the early adenovirus type 2 antiserum, which stained the cytoplasm of about half the synovial cell cultures, some from rheumatoid and some from non-rheumatoid patients.

Antigens, Viral↗
PubMed1979

Normal human tissues contain RNA and antigens related to infectious adenovirus type 2.

Normal human tissues have been found to contain RNA which hybridises with four regions of the adenovirus type 2 genome, including one which contains the transforming gene(s) of this virus. The RNAs have also been extracted from gorilla organs, but not from those of chickens, suggesting that they are a feature of all normal higher primate tissues. Serological test suggest that these homologous RNAs are translated into proteins connected with essentially normal and virus-infected cell functions.

Adenoviruses, Human↗
PubMed1979

Mechanism of persistence of rubella virus in LLC-MK2 cells.

LLC-MK2 cells chronically infected with two strains of rubella virus, HPV-77 and Thomas, have been examined over several months to find out the mechanism of persistence. Evidence is given for the presence of defective particles in these cultures by finding virion RNA which sedimented at 12S instead of the 40S typical of the fully infectious virus. A 'provirus' DNA copy of the rubella virus genome was not detected by methods which included filter hybridization and in situ hybridization, or by treatment of the chronically infected cells with mitomycin C, antinomycin D or 5-bromodeoxyuridine. In addition, the chronically infected cells contained RNA-dependent RNA polymerase activity, but no RNA-dependent DNA polymerase activity.

Animals↗
PubMed1979

Search for viral nucleic sequences in rheumatoid cells.

DNA and RNA were extracted from synovial membranes, synovial fibroblast cells, peripheral blood lymphocytes, and synovial fibroblast cells strains derived from patients with rheumatoid arthritis and other joint conditions. They were hybridised after immobilisation on nitrocellulose filters with iodinated viral nucleic acids extracted from measles, rubella virus, SV--40, and a retrovirus, RD--114. In addition, in situ-hybridisation was carried out on sections of synovial membranes by means of iodinated measles and rubella virus RNA. In no case did any hybridisation occur. Positive control systems included synovial fibroblast strains transformed with SV--40, LLC--MK2 cells chronically infected with rubella virus and RD cells infected with RD--114. It was concluded tht the synovial cells did not contain viral genomes of measles, rubella virus, SV--40, or RD--114, or at least at a level equivalent to the positive control cells.

Arthritis, Rheumatoid↗
PubMed1979

Viruses and lymphocytes in rheumatoid arthritis. I. Studies on cultured rheumatoid lymphocytes.

Synovial fluid lymphocytes from patients with rheumatoid arthritis have been examined for evidence of a productive infection with retroviruses by electron microscopy, labelling with 3H-uredine, growth in soft agar, and culturing in conditioned medium. No such viruses were detected. In addition, the synovial lymphocytes were activated before fusion and cocultivation with several cell lines which have proved permissive for primate retroviruses. Monitoring these cultures subsequently by reverse transcriptase assay, labelling with 3H-uridine, and membrane immunofluorescence gave no indication that retroviruses were present.

Arthritis, Rheumatoid↗
PubMed1978

Antitumour responses induced by short-term pretreatment with tumour cells.

The injection (s.c. or i.p.) of 10(6) live or lethally irradiated methylcholanthrene-induced fibrosarcoma cells into CBA/Ca mice one or 2 days before i.v. challenge with the same tumour inhibited the formation of artificial lung tumour metastases. In addition, it also frequently enhanced the cytostatic effect of peritoneal exudate cells on monolayers of the same tumour. The effects on lung tumour metastasis were not noted if X-irradiated tumour was injected i.v., or if s.c. administration was delayed until one day after i.v. challenge. Similar effects on tumour growth were also observed in C3Hf/Bu mice and (CBA/Ca x A/HeJ) F1 hybrids which were pretreated (s.c.) with tumour shortly before i.v. challenge with the same tumour. Further studies in CBA/Ca mice suggested that the protective effect was tumour-specific, for the growth of i.v. injected tumour was not significantly inhibited by pretreatement with a number of other MC-induced or spontaneous tumours from the same and different strains.

Animals↗
PubMed1976

Attempts to identify viruses in rheumatoid synovial cells.

Synovial fibroblast cell strains derived from the synovial membranes of 7 patients with rheumatoid arthritis were examined for the presence of viruses, in particular leucoviruses. Seven similar synovial strains derived from patients with other arthritic conditions were used as a control group. Evidence of the presence of a virus or a viral genome was looked for by several methods of induction followed by 3H-uridine labelling of the cultures. In addition, the culture supernatant, after induction and after the synovial strains had been co-cultivated with a variety of cell lines from several species, was assayed for the presence of viral RNA-dependent DNA polymerase activity. The DNA-polymerase activity of the synovial cells themselves was also determined. No evidence was found by any of these techniques to indicate the presence of virus or viral information within the synovial fibroblasts.

Arthritis, Rheumatoid↗
PubMed1976

Cytology of rheumatoid synovial cells in culture. IV. Further investigations of cell lines cocultivated with rheumatoid synovial cells.

A previous report described a cell isolate presumed to have arisen by accidental cocultivation (contamination) of the Chang 'liver' cell line and rheumatoid synovial cells. This cell isolate had the same glucose-6-phosphate dehydrogenase isoenzyme as the Chang cell and also some shared antigens. It clearly differed in its karyotype, its ability to grow in semisolid agar, and in the possession of bleb-like projections of the cytoplasmic membrane filled with collections of beaded or granular material. In addition, it had a novel antigen(s) not present in the Chang cell. As these properties might have been acquired from the synovial cells and because the bleb structures resembled those seen in some cell lines transformed by leucovirus the cell isolate has been further studied. Cytochemical methods at the light and electron microscope level showed that the granular material was polysaccharide in nature, probably glycogen. No evidence was found of the presence of a virus or a viral genome using a variety of techniques including attempted induction followed by 3H-uridine labelling of the cultures, and assay of the supernatant fluid from the culture for viral RNA-dependent DNA polymerase. In addition, cell extracts were not found to contain viral RNA-dependent DNA polymerase or RNA-dependent RNA polymerase. No rubella virus or leucovirus interspecies antigens were detected on the cell membranes.

Antigens, Viral↗