Ryan virus: a possible new human pathogen.
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Biomedical subjects
Publications and source records attributed to H B Marsden.
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A study of DNA content by flow cytometry revealed a significant difference between rhabdomyosarcomas, which were mainly non-diploid, and other sarcomas of children which were mainly diploid (p = 0.01). There was no association between DNA ploidy and survival or aggressive behaviour of the tumour as indicated for example by advanced clinical stage or unfavourable histology. While DNA ploidy correlated with age, it did not correlate with any other clinical characteristic. The apparent lack of prognostic value of DNA content may have been masked by some high CV values and overridden by the effect of chemotherapy which was the most significant variable in determining a patient's survival (p = 0.00005).
A monoclonal antibody, RAP-5, raised against the 21,000d ras-oncogene product, p21, was used in an immunoperoxidase staining procedure to study the expression of p21 in normal children's and foetal kidneys, pre-malignant lesions and benign and malignant childhood renal tumours with good, moderate or poor prognosis. ras-p21 was expressed in both normal and foetal kidneys but its distribution in renal tumours differed markedly (p less than 0.01). A quantitative liquid competition radioimmunoassay (RIA) was used to determine ras-p21 level in tissue homogenates. The results were expressed as pg of ras-p21 per microgram protein of tissue extract. There were significant differences in the levels of ras-p21 among various renal tissue extracts (p less than 0.05). Generally it emerged that the amount of ras-p21 was greater in both malignant renal tumours and foetal kidneys compared to normal kidneys, pre-malignant lesions and benign renal tumours.
A monoclonal antibody, M2, was produced by somatic cell hybridisation of splenocytes, from mice immunised with human fetal brain, with the murine myeloma cell line NS-1. Indirect immuno-peroxidase staining of formalin-fixed, paraffin embedded tissue sections showed that, whilst the monoclonal antibody gave a positive reaction with 32/39 astrocytomas from adult patients and 33/36 of children's astrocytomas of the adult histological type, only 17/39 of juvenile astrocytomas were stained. A Chi-squared test showed that the difference in staining between the two groups (adult versus juvenile) was highly significant (p less than 0.0001). In contrast, using a polyclonal antiserum to GFAP, a significantly larger proportion of juvenile astrocytomas than adult astrocytomas stained positively (p less than 0.05). Thus, whereas the distribution of GFAP accorded with the general finding that the degree of malignancy of a tumour correlates with the loss of cell type specific markers, the distribution of M2 reactivity was similar to that of some oncogene products which increase with malignancy. From the flow cytometry data it is apparent that the antigen recognised by M2 is not cell cycle dependent.