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Biomedical subjects

G D Wilson

Publications and source records attributed to G D Wilson.

At least 109 records · Page 6Linked to original sources
PubMed1991

Combined analysis of DNA ploidy index and N-myc genomic content in neuroblastoma.

The aim of the study was to assess, in a group of nonselected patients with neuroblastoma, the prognostic value of both N-myc gene amplification and DNA ploidy index, taking into account potential confounding factors such as age and stage. Of 59 patients studied, 23 were younger than 1 year at diagnosis, 31 presented with stage IV, 10 with stage III, 5 with stage II, 8 with stage I, and 4 with stage IV-S. N-myc genomic content was analyzed by Southern blot hybridization technique and N-myc amplification (greater than or equal to 3 copies/haploid genome) was present in 6 stage IV, 2 stage III, and 1 stage IV-S. The DNA ploidy index was analyzed by flow cytometry. Of the 59 neuroblastomas, 26 were diploid (DNA index, 1) and 33 were aneuploid (DNA index, greater than 1). The majority of the aneuploid tumors (28 of 33) were near-triploid with DNA indexes between 1.25 and 1.68, 4 were near-diploid (DNA index up to 1.18), and 1 was hypotetraploid (DNA index, 1.85). The proportion of near-triploid tumors was significantly greater among patients under 1 year of age and among patients presenting with stages I, II, and IV-S. Interestingly, 0 of 28 near-triploid neuroblastomas exhibited N-myc gene amplification, compared to 9 of 31 in the group of diploid, near-diploid, and hypotetraploid tumors (Fisher's exact test, P less than 0.001). Four factors were significantly related to a high risk of relapse in univariate analysis, i.e., age, stage, DNA index, and N-myc amplification. In multivariate analysis, only N-myc amplification and the DNA index remained significantly associated with a high risk of relapse. The 2-year disease-free survival rate was 94% (95% confidence interval, 77-98%) for patients with near-triploid neuroblastoma, compared to 45 and 11% (95% confidence interval, 32-70 and 4-23%) for patients with diploid or near-diploid tumors, without and with N-myc amplification, respectively. We concluded that the combination of N-myc and DNA index should be included in routine management of neuroblastoma.

Age Factors↗
PubMed1991

Proliferation characteristics of human colorectal carcinomas measured in vivo.

The cell proliferation kinetics of 100 human colonic and rectal adenocarcinomas have been studied in vivo by bromodeoxyuridine infusion and multiparameter flow cytometry. A total of 97 patients, three with synchronous tumours, consented to receive a single bolus dose of 250 mg between 2.4 and 16 h before curative or palliative surgery. By this method, the ploidy pattern, the total and aneuploid labelling indices (LI), the S phase duration (Ts) and the potential doubling time (Tpot) can be estimated. Of the tumours 48 were diploid and 52 were aneuploid. The mean and median total LI of 100 tumours were 9.0 per cent (range 0.7-22.2 per cent). The mean aneuploid LI was 12.1 per cent (median 12.0 per cent, range 2.0-25.5 per cent), and was significantly higher than the total LI (P = 0.01). The labelling index alone is not a sufficient indicator of proliferation, because the Ts also varies within and between tumours. The intertumour range of the Ts varied from 4.0 to 28.6 h. The mean was 14.1 h and the median was 13.1 h. The mean Tpot was 5.9 days (median 3.9 days) with a range of 1.7-21.4 days. No correlation was found between any kinetic parameters and the Dukes' classification or histological classification. The correlation between proliferation and prognosis will be established in due course.

Adenocarcinoma↗
PubMed1991

c-myc protein product is a marker of DNA synthesis but not of malignancy in human gastrointestinal tissues and tumours.

c-myc is a conserved cellular gene. The gene product is a nuclear-bound 62,000 molecular weight phosphoprotein (p62c-myc). Although p62c-myc levels have been measured in colorectal cancers, little is known about the expression of the protein in upper gastrointestinal tumours and tissues. Studies were performed on tumour and mucosal specimens from 87 patients with colorectal cancer, from two with polyposis coli, from six with squamous oesophageal carcinomas and from 18 with gastric carcinomas. The mean p62c-myc content was measured in units of fluorescence in the G1 diploid and G2 diploid peaks of the cell cycle by multiparameter flow cytometry using the 6E10 antibody. The nuclear p62c-myc content increased with DNA synthesis in tumours and mucosa. G2 levels of p62c-myc were higher in glandular mucosa than in adenocarcinomas. No differences in peak nuclear c-myc expression were found in relation to histological grade or to anatomical site of colorectal tumours. There was a broadly inverse relationship between G2 p62c-myc levels in tumours and mucosa and their in vivo 5-bromo-2'-deoxyuridine labelling indices. Nuclear p62c-myc levels are cell cycle related but the protein has not been shown to be a marker of increased tissue proliferation or of gastrointestinal malignancy. The reduction of the nuclear p62c-myc content of many adenocarcinoma cells compared with glandular mucosa cells suggests that reduced synthesis or nuclear retention of the normal protein may be a factor in the development of gastrointestinal adenocarcinomas, although the mechanism by which this may occur is not clear.

Adenocarcinoma↗
PubMed1991

Flow cytometric study of nodular fasciitis, proliferative fasciitis, and proliferative myositis.

DNA ploidy was assessed retrospectively, using flow cytometry, in 13 nodular fasciitis (NF) lesions, three proliferative myositis (PM) lesions, one proliferative fasciitis lesion, and 12 other benign fibrous lesions (BFLs). All were diploid. In view of the large amounts of cellular debris, cell cycle analysis was possible in only seven NF lesions, three PM lesions, and six BFLs. The mean percentage of S phase did not differ markedly between the combination of NF and PM lesions (6.6%) and BFLs (7.1%); the mean percentage of G2 + M phase (5.4%) of the NF/PM lesion combination was twice as large as that of the BFLs (2.5%). No correlation was detected between the cell cycle analysis and the mitotic count, the predominant histologic type in NF lesions, or the predominant stroma in PM lesions.

DNA↗
PubMed1991

Proliferating cell nuclear antigen (PCNA)/cyclin expression during the cell cycle in normal and leukemic cells.

Bivariate flow cytometric analysis of the cell proliferation-associated nuclear protein, identified as the "proliferating cell nuclear antigen" (PCNA)/cyclin and of nuclear DNA content, was performed in quiescent and mitogen-stimulated human peripheral blood lymphocytes, in EUE (human embryonic epithelium) cells, before and after a long-term exposure to a hypertonic (HT) medium, in 4 human leukemic cell lines and in fresh bone marrow (BM) cells from 10 patients with untreated acute non-lymphoblastic leukemia (ANLL). The PCNA/cyclin was detected using both an autoantibody extracted from sera of systemic lupus erythematosus patients and the recently produced mouse monoclonal antibody (MoAb) IgG, named 19F4. The distribution of cells in the different phases of the cycle and the percentage of S-phase cells were obtained in duplicate samples, by DNA flow cytometry (FCM) and by dual parameter FCM of DNA content and bromodeoxyuridine (BUDR) incorporation. In all cell types, the non-specific cytoplasmic background fluorescence was significantly lower with the MoAb compared to that obtained with the polyclonal Ab. The percentage of PCNA-positive cells (both with the autoantibody and the 19F4 MoAb) was always higher than that of S-phase cells by DNA FCM and of BUDR-labeled cells. The pattern of PCNA-expression in both normal proliferating cells and acute leukemia cells, showed that most G0/G1 cells did not express significant amounts of PCNA; an increase in PCNA immunofluorescence was found in late G1 cells, and further increases were observed in S- and G2-M phase cells. PCNA/cyclin, as revealed both with autoantibodies and with the 19F4 MoAb, is associated with all actively or potentially dividing (i.e. G1, S and G2-M) cells thus identifying the proliferative cellular compartment. Combined with the use of multiparameter FCM techniques, the PCNA immunolocalization offers a useful tool to study cell kinetics in normal and leukemic human cell populations.

Antibodies, Monoclonal↗
PubMed1991

Left-handedness, homosexuality, HIV infection and AIDS.

Left-handedness was assessed in a large sample of male homosexuals and male and female heterosexuals, some of whom had been tested for HIV infection, and others of whom had AIDS. No association was found between left-handedness and homosexuality, although there was an excess of left-handers in subjects who had been tested for HIV infection (irrespective of whether the test was negative or positive). This result can be interpreted in three possible ways: as a response bias on the part of left-handers who were aware of the Geschwind hypothesis that left-handedness may confer a vulnerability to AIDS; as due to left-handedness being associated with AIDS infection and the incidence in AIDS patients being artefactually low due to an excess mortality in left-handed AIDS patients; and as left-handers showing both an increased vulnerability of HIV infection and a reduced likelihood of progression of HIV infection into AIDS. Our data are unable to distinguish between these hypotheses. Left-handedness was not associated with any of seventeen specific conditions, including migraine, dyslexia and stuttering.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Fluorescent markers for hypoxic cells: a study of nitroaromatic compounds, with fluorescent heterocyclic side chains, that undergo bioreductive binding.

Several novel compounds having both a 2-nitroimidazole nucleus and a fluorescent ring system in their molecular structure were prepared and evaluated as potential fluorescent probes for hypoxia. Bioreduction of nitroimidazoles, which is inhibited by oxygen, is known to lead to binding of bioreductive metabolites to cellular macromolecules and this provides a mechanism for binding the fluorescent moiety to hypoxic cells. These compounds can incorporate a wide range of fluorophors and can therefore be designed to suit the laser-line wavelengths available for excitation of fluorescence in the flow cytometer. Several nitroimidazoles with naphthalimide side chains were rapidly taken up into cells and became concentrated in the cells, thus reducing their concentration in the extracellular medium. This suggests a potential microscopic bioavailability problem with probes of this type when used in vivo as they would become progressively depleted in the extracellular fluid as they diffused from blood vessels, through layers of packed cells in tumors, to the hypoxic cells where they could undergo hypoxia-specific metabolism. Synthesis of nitroimidazoles with coumarin fluorophors led to several potentially useful probes for hypoxia; substituents on the coumarin fluorophor had a marked effect on the cellular fluorescence of these compounds.

Animals↗
PubMed1991

Flow cytometric evaluation of hypoxic cells in solid experimental tumours using fluorescence immunodetection.

Numerous methods have been proposed for the detection of hypoxic cells using nitroimidazoles labelled with both radioactive and stable isotopes where the isotopic label becomes bound as a result of reductive metabolism of the nitro group. A new probe for hypoxia, 7-(4'-(2-nitroimidazol-l-yl)-butyl)-theophylline, is described where an immunologically recognisable hapten (theophylline) is covalently linked to a 2-nitroimidazole. Bioreduction of the nitroimidazole leads to binding of bioreductive metabolites, and hence the theophylline side-chain, to intracellular molecules. Immunochemical procedures are then used to stain cells containing the bound theophylline using an FITC-conjugated anti-serum. Flow cytometric analysis of stained cells is facilitated by co-staining cellular DNA, which allows discrimination of single cells in the sample and rejection of cell clumps and debris. The alternative use of an immunoperoxidase-conjugated anti-serum has been used to demonstrate the localisation of hypoxic cells in frozen tumour sections.

Animals↗
PubMed1991

Measurement of in vivo urological tumour cell kinetics using multiparameter flow cytometry. Preliminary study.

The in vivo labelling of urological tumour cells using the S phase marker bromodeoxyuridine (BRdU) for histochemical studies is reported. The use of multiparameter flow cytometry (FCM) with BRdU labelling to study tumour proliferation offers significant advantages. It provides simultaneous measurements of the DNA ploidy (DI), the duration of the S phase (Ts), the potential doubling time (Tpot) and the total and aneuploid tumour labelling indices (LI) from a single specimen. Heterogenous tumour cell populations can be measured with high sensitivity. We report a preliminary study to evaluate the method in the measurement of the kinetics of transitional cell carcinoma of the bladder (TCCB). Nineteen patients with TCCB, 1 with leukoplakia of the bladder, 2 with renal carcinoma, 1 with prostatic carcinoma and 1 with a squamous carcinoma of the penis were studied. Of the bladder tumours, 3 were aneuploid, DI = 1.32, 1.58 and 1.89. BRdU uptake was detected in all tumours. The median LI was 1.5% (range 0.5-10.0). In 15/19 tumours the labelling profile was satisfactory for calculation of the Ts and Tpot. The median Ts was 6.2 h and the median Tpot was 17.1 days. This study demonstrates that measurement of multiple parameters of urological tumour proliferation in vivo is possible. These parameters require further assessment as indices of biological aggressiveness and clinical prognosis.

Aneuploidy↗
PubMed1991

Assessment of human tumour proliferation using bromodeoxyuridine--current status.

The study of human tumour proliferation has been facilitated by the development of monoclonal antibodies recognizing halogenated pyrimidines. Flow cytometry can be used to detect the incorporation of bromodeoxyuridine (BUdR) into DNA simultaneously with the measurement of total DNA content. We have studied in excess of 600 tumours using in vivo administration of BUdR. The cell kinetic information generated from this approach is more complete than can be obtained from in vitro incubation with DNA precursors such as tritiated thymidine (3HTdR) or by single parameter DNA analysis. The duration of S-phase (Ts) can be estimated in addition to the labelling index (LI). From these two parameters, the potential doubling time (Tpot) can be calculated. Our data show a wide variation in Ts as well as LI, making both these parameters important variants in determining overall proliferation. Although there is tremendous variation in Tpot between tumours of the same and different types, the median values are surprisingly short at around 5 days. A close relationship exists between the presence of DNA aneuploidy and the proliferation parameters. The clinical relevance of Tpot is currently being assessed independently in two trials of accelerated versus conventional fractionation.

Aneuploidy↗
PubMed1991

[Measurement of the kinetics of cell proliferation of cancer of the oropharynx in vivo by the incorporation of bromodeoxyuridine and flow cytometry].

Forty-six tumors from patients with oropharyngeal carcinoma were analysed by flow cytometry after injection of bromodeoxyuridine (Budr) for the labelling index, the duration of S phase and the potential doubling time (Tpot). The results show large variations in Tpot (from 2.6 to 16.7 days) among these tumors from the same site and with the same histology. The variations in Tpot were not significantly related to TNM status and differentiation grade. However, aneuploid tumors had statistically significant shorter Tpot. The predictive value of Tpot regarding the response to radiotherapy is currently under investigation.

Bromodeoxyuridine↗
PubMed1991

Alterations in dietary carbohydrate, protein, and fat intake and mood state in trained female cyclists.

Seven highly trained female cyclists (age 22 +/- 5 yr, height 165 +/- 6 cm, weight 60 +/- 5 kg, VO2max 55 +/- 6 ml.min-1.kg-1, mean +/- SD) consumed, for 1 wk each, isocaloric diets containing varying levels of carbohydrate, protein, and fat designated as low carbohydrate (LCHO), moderate carbohydrate (MCHO), and high carbohydrate (HCHO). Diets were administered in random order, and each subject consumed all three diet treatments. At the end of each weekly diet treatment, subjects rode on a cycle ergometer at 80% VO2max until fatigued. Cyclists continued light training during the diet treatments. Following each diet treatment and immediately prior to the fatiguing cycle ergometer ride, cyclists completed a Profile of Mood States (POMS) questionnaire. The POMS yields measures of tension (T), depression (D), anger (A), vigor (V), fatigue (F), and confusion (C), as well as providing a total mood score (TMS). Results indicated that subjects on LCHO had significantly (P less than or equal to 0.05) greater T, D, A, and TMS and less V compared with MCHO and HCHO. There were no significant differences between MCHO and HCHO. In the present study, LCHO in conjunction with training and exercise adversely affected the mood state of trained female cyclists as compared with MCHO and HCHO diets.

Adult↗
PubMed1990

In vitro transformation induces abnormal protein thiol levels in rat liver cells.

Cells from an established line of normal rat hepatocytes (IAR 20) were irradiated with 3 Gy gamma-radiation from a cobalt source to generate transformed clones. Cells from four transformed colonies were compared with the parent cell line by flow cytometry following staining with ortho-phthalaldehyde and propidium iodide to quantitate protein thiols and DNA respectively. Transformed cells exhibited an increased variability in cellular protein thiols which was most evident in G1 and S phase. The altered pattern of macromolecular thiol distribution implies early changes in redox state and/or modification of the amounts or types of sulphur-containing proteins in transformed cells.

Animals↗
PubMed1990

Physiological responses to resistance-exercise in athletes self-administering anabolic steroids.

Endocrine and metabolic responses to resistance exercise were compared in 5 athletes self-administering (SL) anabolic steroids and 8 athletes (L) not using these compounds. Exercise consisted of 5 sets of 10 repetitions in the squat and quarter squat. Blood samples were collected before (pre) and immediately after (post) exercise, and following 30 minutes of recovery (post-30). Except for significantly lower lactate concentrations in SL (p less than 0.015) at post-30, the responses to exercise and recovery were similar in both groups. Significantly higher hematocrits (p less than 0.0001), total androgen concentrations (p less than 0.0001), and androgen/cortisol ratios (p less than 0.0001) were observed in the SL group across all time periods. Plasma androgen concentrations increased about 22% in SL following exercise, even though plasma LH concentrations were significantly lower (p less than 0.0001) than in L. Plasma ACTH and cortisol concentrations were not significantly affected. Both groups displayed similar endocrine and metabolic responses to an acute bout of resistance exercise. The higher androgen/cortisol ratios and lower plasma lactate concentrations during recovery are two potential factors which may help explain the lower subjective level of fatigue following training sessions often reported by individuals who use anabolic steroids.

Adrenocorticotropic Hormone↗
PubMed1989

Flow cytometric analysis of protein thiol groups in relation to the cell cycle and the intracellular content of glutathione in rat hepatocytes.

The relationship between protein thiols (PSH) and cell proliferation was examined in ethanol-fixed rat hepatocytes. A new protocol was developed for simultaneous measurement of protein thiol vs. DNA content by flow cytometry. The fluorescent dye o-phthalaldehyde (OPT) was used for flow cytometric measurements of protein thiol groups. The influence of nonprotein thiols was examined by monitoring the cell cycle of cells in which the glutathione content (GSH) was modified by treatment with buthionine sulphoximine (BSO). Three rat liver cell lines (IAR 20, IAR 6.1, IAR 6.1RT7) were used: these cell lines possess different growth characteristics and degrees of tumorigenicity, which made it possible to analyse changes in PSH during normal and deranged cell proliferation. The effects on the cell cycle of the changes in PSH due to the depletion of GSH were measured by 5-bromo-2'-deoxyuridine (BrdUrd) incorporation and flow cytometry. The data obtained can be summarised as follows: a) OPT fluorescence increases with increasing DNA content in all rat liver cell lines examined; b) the greatest variation in PSH content occurs in G1. There is a smaller variation in G2 + M, and PSH levels are relatively invariant throughout S-phase; c) a higher content of PSH is found in the tumorigenic cell lines; d) the amount and distribution of PSH is not affected by BSO treatment; e) kinetic studies indicate that BSO treatment has no effect on the ability of the IAR rat liver cell lines to progress through the cycle.

Animals↗
PubMed1989

Cell proliferation and differentiation in squamous cancer.

Cellular differentiation is generally regarded as an important histological predictor of tumour behaviour. Verrucous carcinoma is a very well-differentiated tumour characterised by slow enlargement and an unsatisfactory response to radiotherapy. Tumour cell kinetic studies using the intravenous administration of bromodeoxyuridine (BrdUrd) before tumour sampling have shown these tumours to have high labelling indices and short duration of DNA synthesis. These values result in short potential cell doubling times of these tumours although they then have a well-differentiated appearance histologically. Study of 20 other squamous cell carcinomas has shown no relationship between grade and cell proliferation.

Bromodeoxyuridine↗