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Biomedical subjects

B W Hancock

Publications and source records attributed to B W Hancock.

At least 91 records · Page 5Linked to original sources
PubMed1993

High incidence of mutations of the p53 gene detected in ovarian tumours by the use of chemical mismatch cleavage.

We have investigated a series of ovarian tumours for evidence of mutations in the p53 tumour suppressor gene. In this study we have made use of the chemical mismatch cleavage technique which, from analyses of other genes, has been shown to consistently identify all point mutations present within a region of DNA. This approach revealed mutations of p53 in 11/20 tumours studied, mainly in exons 5 or 7. After sequencing the relevant regions of the gene it was shown that ten of these mutations would have resulted in an amino acid substitution in the protein and only one represented a polymorphism. The observed incidence of p53 missense mutations in our series (50%) was the highest recorded in ovarian tumours and demonstrated the potential of the mismatch cleavage technique as a reliable method for the detection of p53 mutations in human tumours.

Base Sequence↗
PubMed1993

Phenotypic and cell cycle analysis of human peripheral blood mononuclear cells activated with interleukin-2 and/or OKT3.

The poor clinical response rates of cancer patients following immunotherapy with interleukin-2 (IL-2) and other cytokines has prompted attempts to enhance the response rate by using combinations of biological response modifiers. Peripheral blood mononuclear cells (PBMC) respond to interleukin-2 and mediate non-MHC-restricted cytotoxicity and cell proliferation. The addition of anti-human CD3 monoclonal antibody OKT3 has been reported to increase cytotoxicity by increasing the number of cells generated in response to the two stimuli; however, our results could not confirm this finding. In the present study we have investigated the proliferative capacity of individual populations of PBMC responding to IL-2 and OKT3 compared to either stimulus alone, in order to identify possible reasons for the failure of OKT3 to generate enhanced cytotoxic responses. PBMC were stained with monoclonal antibodies to surface antigens and propidium iodide in order to determine the phenotype of populations of PBMC progressing through the cell cycle. OKT3 alone caused an increase in PBMC progressing through the cell cycle, and addition of recombinant human IL-2 (rhIL-2) sustained this response. A higher percentage of CD56- or CD16-positive cells responded to the rhIL-2 alone, but the addition of OKT3 lowered the percentage of this phenotype and increased the number of CD3-positive T cells, which additionally demonstrated an increased CD25 expression. Comparison of the phenotypes progressing through the cell cycle in response to OKT3 plus rhIL-2 or rhIL-2 alone showed that a higher percentage of all populations responded to OKT3 plus rhIL-2, compared to IL-2 alone. Using flow cytometric cell sorting, those populations of cells with cytolytic activity were identified. Using flow cytometry, it was also possible to show minority cell populations (i.e., those representing less than 5% of the total number of cells) responding to individual stimuli and entering the cell cycle. This technique therefore offers distinct advantages over conventional proliferation assays.

Antigens, CD↗
PubMed1993

2D-gel analysis of proteins in chronic lymphocytic leukemia cells and normal B-lymphocytes.

Protein synthesis was analysed in leukaemic cells from 10 chronic lymphocytic leukaemia (CLL) patients by 2D-gel electrophoresis of 14C-labelled proteins. There appeared to be only minor differences between each of the CLL samples, but there was evidence that the level of expression of a few of the proteins might have correlated to the stage of the disease. Comparison of the CLL samples to populations of normal B-lymphocytes demonstrated marked differences in protein synthesis between the leukaemic and non-malignant cells. We subsequently used the fluorescence activated cell sorter (FACs) to separate CD5+ from CD5- B-lymphocytes, but observed that the protein synthesis exhibited by these two populations was essentially the same, and both were very different to that observed in CLL cells. The significance of these observations with respect to the origins of CLL is discussed.

Antigens, CD↗
PubMed1993

Undergraduate medical teaching in departments of oncology in the United Kingdom: a questionnaire survey.

A questionnaire survey has been conducted to assess the nature and extent of teaching given to undergraduate medical students in departments of Oncology within the United Kingdom. Postal questionnaires were sent to 58 departments of Radiotherapy/Oncology and 30 departments of Medical Oncology. This included both teaching and nonteaching departments. Response rates were 84.5% (49 replies) and 90% (27 replies), respectively. Of the responders, 26 Radiotherapy/Oncology departments (53%) and 21 Medical Oncology departments (78%) have a regular commitment to undergraduate medical teaching, the majority being units affiliated to teaching hospitals. The time spent in teaching, methods of teaching, the teaching curriculum, and other details have been documented and are summarised. The information obtained leads us to conclude that there is a considerable variation between departments with regard to teaching commitments and the curriculum. Such variations appear to be primarily centre oriented rather than specialty biased. The survey also raises a number of issues regarding undergraduate medical teaching with reference to oncology, which are discussed.

Academic Medical Centers↗
PubMed1993

Palliative care of patients with terminal cancer.

Palliative (terminal) care is now recognized worldwide as an important, multidisciplinary aspect of the continuing care of patients with incurable cancer. Symptom control and quality-of-life are of the essence. Various treatment methods are available, and radiotherapy and chemotherapy (used appropriately) are important modalities. Palliative care has to be set against a background of planning, development, and cost-benefit analyses.

Humans↗
PubMed1993

Investigation of BCL-2 gene rearrangements in a United Kingdom series of low and high grade non-Hodgkin's lymphomas.

Rearrangements of the BCL-2 gene are thought to be the most frequent genetic changes that occur in non-Hodgkin's lymphomas (NHL), and are particularly associated with follicular low grade disease. Wide variations in the frequency of these rearrangements have, however, been reported in studies of NHL series from different parts of the world. We were therefore interested to determine the frequency of BCL-2 gene rearrangements in the different grades of NHL from a U.K. series. We have done this by using a combination of Southern blot hybridization and polymerase chain reaction (PCR) analysis. The frequencies of rearrangements in our series were 9/20 (45%) in low grade follicular NHL, 1/8 (12.5%) in low grade lymphocytic and 5/19 (26%) in high grade NHL. However, estimation of the high grade value was complicated by the fact that a number of the high grade samples in our series were from patients who had transformed from low grade follicular disease. If the patients were ranked on the basis of whether they had a history of low grade follicular disease then the frequency of BCL-2 rearrangement remained the same 13/29 (45%), but was only 1/10 (10%) in high grade NHL with no history of follicular disease. The former figure was intermediate between those reported for the USA and Japan series, but the latter high grade figure was the lowest reported from any series. The significance of BCL-2 rearrangements in the evolution of both low and high grade NHL is discussed.

Base Sequence↗
PubMed1993

Investigation of the expression of housekeeping genes in non-Hodgkin's lymphoma.

Studies of quantitative changes in gene expression in malignant cells have often used housekeeping genes as controls against which the level of expression of a gene under study could be compared. We have now examined whether the expression of the most commonly used of these housekeeping genes can be regarded as reliable controls for gene expression studies in non-Hodgkin's lymphoma (NHL). We have used Northern blot analysis to compare the levels of expression of beta-actin, alpha-tubulin, beta 2-microglobulin and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) to that of ribosomal RNA. These studies demonstrated that whereas there was a reasonable correlation between the relative levels of rRNA and housekeeping gene expression in reactive hyperplastic nodes, there were major differences in the relative levels of expression of the housekeeping genes in both low and high grade lymphomas; only GAPDH showed any degree of consistency. These observations indicated that housekeeping gene expression was not a reliable control for estimating changes in the level of expression of other genes in NHL, and instead suggested that 18S or 28S rRNA expression offered a more accurate method of RNA quantitation.

Actins↗
PubMed1993

Structural abnormalities of the X chromosome in non-Hodgkin's lymphoma.

It has recently been reported that additional X chromosomes occur in over 30% of B-cell non-Hodgkin's lymphomas (NHL), and that monosomy of the X chromosome occurs in 38% of female patients with T-cell leukaemia or lymphoma. These observations have suggested a possible role for the X chromosome in the evolution of NHL. We have now examined 280 cases of NHL, and have identified 19 examples of structurally altered X chromosomes in the malignant cells from 17 of these cases. These abnormalities were mainly characterized by either a translocation involving Xp22, or a translocation/deletion involving Xq28. The relevance of these observations is discussed with respect to other published reports, and together they suggest that lymphoma-associated oncogenes may exist on the X chromosome at bands p22 or q28.

Aneuploidy↗
PubMed1992

Variable expression of the interleukin-2 receptor alpha chain and MYC genes in lymphocytes from renal cell carcinoma patients treated with interleukin-2.

We have studied the expression of the interleukin-2 receptor alpha chain, c-MYC and L-MYC genes in lymphocytes obtained from four renal cell carcinoma patients undergoing an interleukin-2 clinical trial. Two of these patients exhibited stable disease after the interleukin-2 therapy and two exhibited progressive disease. Analysis of mRNA levels by dot blot hybridization indicated that changes in the expression of both the interleukin-2 receptor alpha chain and c-MYC genes were erratic and varied widely between patients. L-MYC expression was not observed in any sample. There appeared to be little correlation between the changes in gene expression and parameters such as thymidine incorporation, the proportion of CD25 positive cells present or cytotoxic activity. The situation in vivo therefore appears to be more complex than would be predicted from in vitro studies.

Antigens, CD↗
PubMed1992

Cytogenetic analysis of a United Kingdom series of non-Hodgkins lymphomas.

We describe cytogenetic analyses of cells derived from 40 non-Hodgkins lymphoma (NHL) node biopsies, 23 of which were from patients who had not been treated before biopsy. We noted that the chromosomes most frequently gained were X (32%), 12 (27%), and 3 (24%). Monosomies were much less common; loss of chromosome 13 (13.5%) was most frequent. Structural abnormalities primarily involved chromosomes 14 (70%), 1 (40.5%), 18 (38%), 6 (35%), and 17 (22%). Low-and high-grade disease showed similar patterns of structural changes; however, a markedly greater number of chromosome gains were associated with low-grade disease. Biopsy samples from patients who had previously been treated showed an increased frequency of structural abnormalities, as well as a significantly larger number of chromosome gains. The importance of these observations, particularly with regard to possible oncogene involvement in lymphoma evolution, is discussed.

Aneuploidy↗
PubMed1992

The augmentation of lymphokine-activated killer activity following pulsing of human peripheral blood mononuclear cells with recombinant human interleukin-2.

The short-term exposure of peripheral blood mononuclear cells (PBMC) to recombinant human interleukin-2 (rhIL-2) at 37 degrees C leads to the generation of lymphokine-activated killer (LAK) activity similar in magnitude to that obtained by the exposure of PBMC to rhIL-2 continuously for 3-5 days. In order to investigate whether the required signal for LAK induction occurred during the short exposure to rhIL-2 or at a later point in the induction phase, PBMC were exposed to rhIL-2 for 1 h at 4 degrees C and then exposed to a low-pH wash to remove bound IL-2 from its receptor. PBMC treated in such a way showed increased LAK activity and proliferation compared to cells exposed to rhIL-2 alone. Expression of the p55 (alpha) subunit of the IL-2 receptor was also increased. In order to cause the augmentation, a lowering of the pH below 4.0 was necessary, and exposure of PBMC to low pH alone (in the absence of rhIL-2) failed to cause activation. Another relevant feature was a transient increase in the expression of the p75 subunit of the IL-2 receptor (beta chain) immediately following the exposure to low pH and the release of interferon gamma, tumour necrosis factor alpha and IL-6; activation was blocked by the inclusion of neutralising antisera raised against rhIL-2 and interferon gamma, thus demonstrating that the endogenous release of these cytokines is important for activation.

Cytokines↗
PubMed1992

Treatment of malignant melanoma and renal cell carcinoma with recombinant human interleukin-2: analysis of cytokine levels in sera and culture supernatants.

In this study we evaluated the clinical response of 12 patients with malignant melanoma and renal cell carcinoma (RCC) following administration of recombinant human interleukin-2 (rhIL-2) by continuous infusion. Serum samples taken before, during and following sequential courses of IL-2 were assayed for the presence of tumour necrosis factor alpha (TNF-alpha) IL-1 alpha, IL-6 and interferon gamma (IFN-gamma) and the presence or changes in these cytokines were examined with respect to clinical response data: our results did not show any direct correlation between the parameters measured and clinical outcome. In addition, peripheral blood mononuclear cells (PBMC) derived from 3 RCC patients were cultured in a serum-free environment and the resulting supernatants assayed for the production of these cytokines and compared to the corresponding serum levels. During one or more courses of treatment only 1 patient, who had metastatic bone disease, demonstrated detectable serum TNF-alpha; serum IL-6 levels were elevated in a proportion of all patients studied and a sustained IL-6 response occurred in a patient who had complete disease remission; IL-1 alpha was detected in the serum of 3 RCC patients; IFN-gamma could not be detected in any serum sample tested. Cytokine levels in sera and supernatants derived from 3 RCC patients were compared but no correlation was found: TNF-alpha and IL-6 were shown to be present at much higher concentrations in supernatants when compared to sera whereas the levels of IL-1 alpha were almost undetectable. This lack of correlation is probably due to the presence of "interfering" proteins in sera which either depress or enhance the ability to detect cytokines in sera using enzyme immunoassays.

Carcinoma, Renal Cell↗
PubMed1992

Signal transduction in murine B16 melanoma cells.

The relationship between lung colonization and signal transduction was investigated for six B16 melanoma variants. A range of experimental metastatic potential (as determined by lung colonization), forskolin-stimulated cyclic AMP accumulation and FCS-stimulated protein kinase C activity was found. The major findings were that: (1) cells with the highest agonist-stimulated cyclic AMP production were those with the highest level of membrane-associated protein kinase C activity; (2) clones which differed in protein kinase C levels and distribution did so in the presence but not in the absence of foetal calf serum; and (3) no simple relationship was seen between either signal transduction system and lung colonization for all six variants. Altered ras expression was also excluded as an explanation for the differences in signal transduction and lung colonization potential which were observed. We conclude that differences in signal transduction in vitro between these cells do not relate simply to lung colonization potential in vivo.

Animals↗
PubMed1992

LOPP alternating with EVAP is superior to LOPP alone in the initial treatment of advanced Hodgkin's disease: results of a British National Lymphoma Investigation trial.

PURPOSE: The purpose of this randomized trial was to compare the efficacy of eight cycles of chlorambucil, vincristine, procarbazine, and prednisone (LOPP) with four cycles of LOPP that alternate with four cycles of etoposide, vinblastine, Adriamycin (doxorubicin; Familitalia Carlo Erba, Ltd, UK), and prednisone (EVAP) in patients with advanced Hodgkin's disease. PATIENTS AND METHODS: Between June 1983 and December 1989, 594 patients were entered onto the study. Of the 594, 295 patients were allocated to receive LOPP, and 299 were allocated to receive LOPP/EVAP. RESULTS: The complete remission (CR) rates were 57% and 64%, respectively, after initial chemotherapy (difference not significant [NS]), and 65% and 75%, respectively, after the subsequent administration of radiotherapy to residual masses (P less than .01). The procedure associated mortality in the LOPP and LOPP/EVAP arms was 1% and 3%, respectively. The actuarial CR relapse-free survival was significantly greater in the LOPP/EVAP arm (P less than .001) as was the overall survival (P less than .05). The CR relapse-free rate, disease-free survival (DFS) rate, and overall survival rate at 5 years were 52%, 32%, and 66%, respectively, in the LOPP arm, compared with 72%, 47%, and 75% in the LOPP/EVAP arm, respectively. CONCLUSION: These results indicate that LOPP and EVAP is superior to LOPP alone as initial treatment for advanced Hodgkin's disease.

Actuarial Analysis↗
PubMed1991

Malignant melanoma and renal cell carcinoma: immunological and haematological effects of recombinant human interleukin-2.

The immunological and haematological effects of continuous infusion of recombinant human interleukin-2 (rhIL-2) in 6 patients with metastatic melanoma and 6 with disseminated renal cell carcinoma are reported. In patients with malignant melanoma dacarbazine was given before IL-2; in renal cell carcinoma IL-2 alone was given. In malignant melanoma, 1 complete (CR) and 1 partial response (PR) were seen; 2 patients had stable disease (SD) and 2 progressive disease (PD). In renal cell carcinoma 4 patients had SD and 2 PD. Toxicity of IL-2 therapy was minimal. All patients showed increased cytotoxicity, that was not major histocompatibility complex restricted, towards target cells sensitive and insensitive to natural killer cells. These activities varied between individual patients and were less marked in cases of renal cell carcinoma. Cellular proliferative responses increased in all patients, being consistently higher following the first course of therapy, as did HLA-DR, CD16 and CD25 activation marker expression. Hypersegmentation of neutrophils and eosinophilia were commonly observed, and in renal cell carcinoma these changes were accompanied by abnormal lymphocyte morphology.

Aged↗