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Biomedical subjects

A M Campbell

Publications and source records attributed to A M Campbell.

At least 19 recordsLinked to original sources
PubMed1992

Dual colour flow cytometry of p53 and c-erbB-2 expression related to DNA aneuploidy in primary and metastatic breast cancer.

DNA aneuploidy and p53 or c-erbB-2 expression were simultaneously measured in 29 breast tumours by two-colour flow cytometry. (i) The majority of tumours had some cells expressing either p53 (5-68%) or c-erbB-2 (1-56%). (ii) Expression of p53 and c-erbB-2 was observed mainly in the aneuploid population of mixed aneuploid and diploid tumours but there was no significant correlation with a specific DNA index. Aneuploid tumours contained higher percentages of c-erbB-2 positive cells (average 25%) than purely diploid tumours (average 15%) but this just failed to reach significance (P = 0.074). No relevant trends were noted for p53 expression. (iii) Significantly increased c-erbB-2 expression was observed in stage 2 tumours (26%) compared to stage 1 tumours (12%) (P = 0.001) with no trend evident for p53 expression. (iv) The metastatic tumour in the axillary node contained similar or slightly higher percentages of positive cells than the matched primary tumour.

Aneuploidy↗
PubMed1992

The alternative carboxyl termini of avian cardiac and brain sarcoplasmic reticulum/endoplasmic reticulum Ca(2+)-ATPases are on opposite sides of the membrane.

The sarcoplasmic/endoplasmic reticulum slow-twitch or cardiac Ca(2+)-ATPase (SERCA2) is expressed as two forms (SERCA2a and SERCA2b) which vary at their extreme carboxyl termini. SERCA2a and SERCA2b are derived from alternatively spliced primary transcripts of the same gene. These two alternative carboxyl termini are highly conserved in mammals (Eggermont, J. A., Wuytack, F., De Jaegere, S., Nelles, L., and Casteels, R. (1989) Biochem. J. 260, 757-761; Lytton, J., and MacLennan, D. H. (1988) J. Biol. Chem. 263, 15024-15031) and birds (Campbell, A. M., Kessler, P. D., Sagara, Y., Inesi, G., and Fambrough, D. M. (1991) J. Biol. Chem. 266, 16050-16055). The topology of SERCA2a is believed to be identical to the fast-twitch Ca(2+)-ATPase (SERCA1) with 10 membrane-spanning domains. Based on hydropathy analysis, the extended carboxyl terminus of SERCA2b is predicted to span the endoplasmic reticulum (ER) membrane an additional (i.e. 11th) time. We have added the human c-myc epitope, a 10-amino acid sequence recognized by monoclonal antibody 9E10, onto the carboxyl termini of SERCA2a and SERCA2b to test whether or not their carboxyl termini are on the same side of the ER membrane. The added epitopes do not appear to disrupt topology as judged from unaltered Ca2+ transport. Immunocytochemical studies demonstrate that SERCA2a and SERCA2b have their carboxyl termini on opposite sides of the ER membrane; SERCA2a's is in the cytosol and SERCA2b's is in the ER lumen.

Amino Acid Sequence↗
PubMed1992

Statistical analyses of counts and distributions of restriction sites in DNA sequences.

Counts and spacings of all 4- and 6-bp palindromes in DNA sequences from a broad range of organisms were investigated. Both 4- and 6-bp average palindrome counts were significantly low in all bacteriophages except one, probably as a means of avoiding restriction enzyme cleavage. The exception, T4 of normal 4- and 6-palindrome counts, putatively derives protection from modification of cytosine to hydroxymethylcytosine plus glycosylation. The counts and distributions of 4-bp and of 6-bp restriction sites in bacterial species are variable. Bacterial cells with multiple restriction systems for 4-bp or 6-bp target specificities are low in aggregate 4- or 6-bp palindrome counts/kb, respectively, but bacterial cells lacking exact 4-cutter enzymes generally show normal or high counts of 4-bp palindromes when compared with random control sequences of comparable nucleotide frequencies. For example, E. coli, apparently without an exact 4-bp target restriction endonuclease (see text), contains normal aggregate 4-palindrome counts/kb, while B. subtilis, which abounds with 4-bp restriction systems, shows a significant under-representation of 4-palindrome counts. Both E. coli and B. subtilis have many 6-bp restriction enzymes and concomitantly diminished aggregate 6-palindrome counts/kb. Eukaryote, viral, and organelle sequences generally have aggregate 4- and 6-palindromic counts/kb in the normal range. Interpretations of these results are given in terms of restriction/methylation regimes, recombination and transcription processes, and possible structural and regulatory roles of 4- and 6-bp palindromes.

Animals↗
PubMed1992

T cell receptor gamma/delta expression on lymphocyte populations of breast cancer patients.

The quantitative distribution and phenotype of gamma/delta lymphocytes in the peripheral blood (PBL), tumour draining lymph node (LNL) and tumour infiltrating lymphocytes (TIL) from breast carcinoma patients were determined by one- and two-colour flow cytometry. The TCR-gamma/delta + cells generally expressed the T cell lineage antigen CD3. The proportions of such cells were variable but generally small from all the three sources. Phenotypic analysis revealed that the CD8 marker was consistently and predominantly observed on gamma/delta + CD3+ cells in the tumour infiltrate, whereas CD4 expression, while generally low, was noted on a significant percentage (median 10%) of LNL gamma/delta + lymphocytes. In both PBL and LNL the predominant gamma/delta cell population was CD4-8-.

Antibodies, Monoclonal↗
PubMed1992

Over- and under-representation of short oligonucleotides in DNA sequences.

Strand-symmetric relative abundance functionals for di-, tri-, and tetranucleotides are introduced and applied to sequences encompassing a broad phylogenetic range to discern tendencies and anomalies in the occurrences of these short oligonucleotides within and between genomic sequences. For dinucleotides, TA is almost universally under-represented, with the exception of vertebrate mitochondrial genomes, and CG is strongly under-represented in vertebrates and in mitochondrial genomes. The traditional methylation/deamination/mutation hypothesis for the rarity of CG does not adequately account for the observed deficiencies in certain sequences, notably the mitochondrial genomes, yeast, and Neurospora crassa, which lack the standard CpG methylase. Homodinucleotides (AA.TT, CC.GG) and larger homooligonucleotides are over-represented in many organisms, perhaps due to polymerase slippage events. For trinucleotides, GCA.TGC tends to be under-represented in phage, human viral, and eukaryotic sequences, and CTA.TAG is strongly under-represented in many prokaryotic, eukaryotic, and viral sequences. The CCA.TGG triplet is ubiquitously over-represented in human viral and eukaryotic sequences. Among the tetranucleotides, several four-base-pair palindromes tend to be under-represented in phage sequences, probably as a means of restriction avoidance. The tetranucleotide CTAG is observed to be rare in virtually all bacterial genomes and some phage genomes. Explanations for these over- and under-representations in terms of DNA/RNA structures and regulatory mechanisms are considered.

Animals↗
PubMed1992

Flow cytometric analysis of tumour infiltrating lymphocyte activation and tumour cell MHC class I and II expression in breast cancer patients.

The primary tumour cells and tumour infiltrating lymphocytes (TILs) of 31 breast cancer patients have been analysed by dual colour flow cytometry to determine whether the phenotype and/or activation status of the TILs bears any relationship to the expression of MHC antigens on the tumour cells. The phenotype and activation status of 5000 TILs were studied using Mabs to CD4, CD8, HLA DR, CD25 (the low affinity inducible IL-2 receptor) and the transferrin receptor and related to Class I and Class II MHC expression on 5000 primary tumour cells. On the tumour cells, Class I MHC expression ranged from 1-74%, averaging 12.9%. HLA DR expression ranged from 1-69% averaging 14.3%. When the phenotypic proportions of the lymphocytic infiltrate were analysed there was found to be a correlation between tumour expression of Class I MHC and the proportion of both CD4+ (P less than 0.05) and CD8+ (P less than 0.02) T cells within the tumour. No such relationship was found with the MHC Class II antigen. When TIL activation markers were analysed, the percentage of CD8+ TILs positive for HLA DR expression correlated strongly with the expression of Class I (P less than 0.001) and Class II (P less than 0.001) antigens on the tumour cells. The percentage of CD4+ TILs positive for HLA DR expression also correlated significantly, but less strongly with the expression of Class I (P less than 0.01) and Class II (P less than 0.02) antigen expression on the tumour cells. The percentage of CD4+ TILs positive for CD25 expression correlated with both Class I (P less than 0.05) and Class II (P less than 0.03) expression on the tumour cells while the percentage of CD8+ TILs positive for CD25 did not. The percentage of TILs bearing the transferrin receptor showed no measurable correlation with the expression of either class of MHC antigen on the tumour. The data suggest that MHC expression on the tumour cells has a selective effect on the response capacity of different parts of the immune system.

Breast Neoplasms↗
PubMed1992

Analysis of clonality of tumour infiltrating lymphocytes in breast cancer and uveal melanoma.

Fresh tumour infiltrating lymphocytes (TILs) from 6 uveal melanomas and 4 breast cancers were analysed by flow cytometry with a panel of 6 monoclonal antibodies to V beta regions of the T cell receptor (V betas 5a, 5b, 5c, 6, 8a and 12a). With a single exception where one TIL sample lacked V beta 12a, lymphocytes from both tumour and blood contained cells reactive with all 6 probes, and no probe was highly dominant or missing. The proportions of reactive cells differed between tumour and blood within each patient. The data indicate that while tumour infiltrating lymphocytes have a capacity to locate selectively within the tumour they nonetheless comprise a population expressing a diversity of TCR V beta genes.

Antibodies, Monoclonal↗
PubMed1992

Flow cytometric analysis of tumour-draining lymph nodes in breast cancer patients.

The phenotype and activation status of lymphocytes from the peripheral blood and axillary lymph nodes of 40 patients with breast cancer were analysed using flow cytometry and compared with lymphocytes from the blood and lymph nodes of 7 control subjects. There was little difference in the overall proportions of T and B lymphocytes but there was a much larger population of B cells bearing surface IgG and a greater number of CD4+ helper T cells, particularly in the regional nodes, in the breast cancer patients. Many more T cells in the cancer patients were found to be carrying the HLA DR and Tac antigens. The axillary lymph nodes were the major site of B cells and CD4+ T cells whilst the primary tumour was the source of the CD8+ suppressor/cytotoxic T cells. Any immune response appeared to be largely loco-regional and may therefore destroyed by conventional surgery or radiotherapy.

Axilla↗
PubMed1992

Aneuploid subpopulations in tumour-invaded lymph nodes from breast cancer patients.

Fresh, paired primary tumours and lymph node metastases from breast cancer patients were compared by DNA flow cytometry. Although 65% of primary tumours were aneuploid, the detection of aneuploid peaks in corresponding nodal metastases was rare (only 6 cases out of 25) in single-parameter DNA analysis. Detection of aneuploid subpopulations in lymph nodes was greatly improved in dual-parameter DNA analysis using an anticytokeratin (CK) antibody which allowed ploidy determination on CK+ epithelial cells alone. Examination of 12 lymph nodes for CK+ cells revealed the presence of both diploid and aneuploid tumour cells in tumour invaded nodes. In patients with multiploid primary tumours, a subpopulation of the primary aneuploid cells was dominant in the nodal metastases. This suggests that aneuploidy is an integral property of metastatic cells and that within a primary tumour a subpopulation may have a higher metastatic potential.

Aneuploidy↗
PubMed1992

A quick accurate method for measuring the microwave dielectric properties of small tissue samples.

A resonant cavity perturbation technique has been developed which provides a quick, simple and accurate method of measuring the microwave dielectric properties of small, easily prepared samples of tissues, tissue-simulating materials and biological fluids. The method gives dielectric properties averaged over the sample volume. The measurement accuracy with the apparatus used is +/- 2.2% for relative permittivity and +/- 3.5% for the loss factor for most tissue and biological material samples. With appropriate basic microwave equipment the method can be applied over the 1.5-6 GHz range of frequencies of interest for active and radiometric tissue microwave imaging.

Adipose Tissue↗
PubMed1992

Dielectric properties of female human breast tissue measured in vitro at 3.2 GHz.

Complex permittivities of in vitro diseased and undiseased human female breast tissues have been measured at 3.2 GHz using a resonant cavity technique. Ranges of dielectric properties and water contents of these tissues are presented. Experimental data are compared with models predicted from mixture equations. Measured permittivity data lie within limits set by two-phase mixture theory, but some conductivity data are in excess of those expected for a mixture of saline and protein. At any particular microwave frequency in all tissue of a given type, the relationship between permittivity and conductivity may be parametrized using the Debye relaxation equations. For each breast tissue type a characteristic relaxation frequency was calculated and found to be lower than that of physiological saline at the same temperature. It is concluded that the dielectric relaxation of tissue water is not the only dispersive process occurring at this frequency: dielectric relaxation of bound water and the tail end of a beta-dispersion may also contribute to the dielectric properties. The similarity of the dielectric properties of benign and malignant breast tumours measured in this work suggest that in vivo dielectric imaging methods will not be capable of distinguishing them.

Adipose Tissue↗
PubMed1992

Anaesthesia in a patient with Noonan's syndrome and cardiomyopathy.

A 5-year-old girl with Noonan's syndrome and a hypertrophic cardiomyopathy presented for myelography and subsequently, laminectomy. The anaesthetic management of the patient is described and the potential problems of the facial, cardiovascular and skeletal abnormalities associated with the condition are discussed.

Anesthesia, General↗
PubMed1992

c-fos proto-oncogene expression in bronchial biopsies of asthmatics.

c-fos, a proto-oncogene regulating the transcription of many genes, plays a critical role in the cell cycle and differentiation and may be involved in the regulation of inflammation in asthma. Very low levels of c-fos are detectable in most human cells, and its expression is rapidly and transiently increased by multiple factors, some of which are involved in the airways inflammation of asthma (histamine, eicosanoids, and cytokines). The presence of c-fos protein, as detected by immunofluorescence, and the immunoreactivity of PCNA, a cell proliferation marker, were examined in bronchial biopsies obtained from 12 asthmatics and 10 normal subjects. Biopsies of eight of 12 asthmatics expressed c-fos versus none of 10 normal subjects. The expression was heterogeneous and localized to cells positive for anti-cytokeratin monoclonal antibody, indicating their epithelial origin. On the other hand, PCNA immunoreactivity was only observed in one asthmatic and one control subject but it was not related with c-fos expression. This study demonstrates the induction of c-fos in epithelial cells of asthmatics, suggesting a role for this proto-oncogene in activation rather than in proliferation.

Adult↗
PubMed1992

In vitro activation of bronchoalveolar lavage cells by house dust mite allergens.

Mast cells represent a small but important proportion of bronchoalveolar lavage cells and are directly exposed to environmental triggers including allergens. Histamine and PGD2 are mediators released during the activation of mast cells. Fourteen patients allergic to Dermatophagoides pteronyssinus were studied. After bronchoalveolar lavage the unfractionated cell pellet containing metachromatic cells was submitted to allergen challenge using three concentrations of a standardized Dermatophagoides pteronyssinus extract and one concentration of A23187 (2.5 microM). The release of histamine was measured by radioimmunoassay using a monoclonal antibody against acylated histamine and PGD2 was measured by enzyme immunoassay using a polyclonal antibody against methoxamine-PGD2. Histamine was released in 13/14 patients following stimulation of the cells with A23187 and 12/14 patients after stimulation with Dermatophagoides pteronyssinus extract. The release of histamine was 3.5-fold greater when cells were stimulated by the Dermatophagoides pteronyssinus extract than with A23187. PGD2 was released in 10/12 patients when cells were stimulated with A23187 and 6/14 patients in the case of Dermatophagoides pteronyssinus extract stimulation. In the latter case, the mean release was not significantly greater than baseline. For histamine, the maximum release usually occurred with the more concentrated extract whereas in the experiments where PGD2 was released, maximal generation usually occurred with the lowest concentration used. There was no correlation between the severity of asthma and the release of mediators. This study confirms the activation of metachromatic cells by allergen and shows some heterogeneity in the release of granule and membrane-derived mediators.

Adult↗
PubMed1991

Nucleotide sequences of avian cardiac and brain SR/ER Ca(2+)-ATPases and functional comparisons with fast twitch Ca(2+)-ATPase. Calcium affinities and inhibitor effects.

Two similar forms of the cardiac/slow Ca(2+)-ATPase (SERCA2a and SERCA2b), differing in sodium dodecyl sulfate-polyacrylamide gel electrophoresis mobility, are expressed in chicken heart and brain (Kaprielian, Z., Campbell, A. M., and Fambrough, D. M. (1989) Mol. Brain Res. 6, 55-60). In the current study, cDNAs encoding each form were cloned and sequenced. Chicken SERCA2a is 94% identical to its rabbit homologue, while SERCA2b has an extended carboxyl terminus with 38 of 49 amino acids identical to mammalian homologues. SERCA2b mRNA contains the SERCA2a encoding sequence within its 3'-untranslated region. Chicken genomic DNA sequence reveals that the alternate RNA splicing used to produced SERCA2a and SERCA2b subtypes involves a splice site within an exon. Tissue culture cells expressing the avian SERCA2a, SERCA2b, and SERCA1, each targetting to the endoplasmic reticulum, were used to measure Ca2+ affinities and inhibitor effects; no differences among the three pumps were detected.

Amino Acid Sequence↗