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G D Wilson

Publications and source records attributed to G D Wilson.

At least 19 recordsLinked to original sources
PubMed1995

Proliferation measurements with flow cytometry Tpot in cancer of the uterine cervix: correlation between two laboratories and preliminary clinical results.

PURPOSE: To assess the prognostic value of the pretreatment potential doubling time (Tpot) in carcinoma of the uterine cervix, relative to other established clinical factors. METHODS AND MATERIALS: Fifty-two patients with cervical cancer were studied prospectively from March 1991 to October 1993. Pretreatment evaluation included examination under anesthesia and tumor biopsy 6 h following the intravenous administration of bromodeoxyuridine (200 mg). Tpot was determined by deriving the labeling index (LI) and S-phase synthesis time (Ts) using flow cytometry. Six patients were not evaluable and excluded. The remaining 46 patients (average age 55 years) were treated uniformly with radical radiation therapy. There were 39 squamous carcinomas and 7 adenocarcinomas. Fédération Internationale de Gynécologie et d'Obstétrique (FIGO) stages were: Ib and IIa, 12 patients; IIb, 18 patients; III and IV, 16 patients. The median external beam dose was 50 Gy (range, 45-52.8 Gy) delivered in 25 fractions. The median intracavitary dose was 40 Gy (range. 25.5-40 Gy) delivered with a single line source to a point 2 cm lateral of the midline, with a mean dose rate of 0.71 Gy/h. The median overall treatment time was 45 days (range, 34-73 days). As of July 31, 1994, 12 patients had died of disease, and the average follow-up for alive patients was 1.4 years (range, 0.5-3.3 years). RESULTS: There were 27 tumors with diploid deoxyribonucleic acid (DNA) content and 19 tumors were aneuploid. The median and mean Tpot for the 46 patients were 5.5 and 6.6 days, respectively [range, 2.0-25.6 days; coefficient of variation (CV), 74%]. For 25 patients where Tpot measurements were performed at two separate laboratories, there was a fair correlation (r = 0.74), but systematic differences were detected suggesting that the lack of agreement was not simply due to intratumoral variation. To date, 30 patients remained disease free, while 8 patients had pelvic failure and 9 patients developed distant metastases as the first failure site (1 patient developed both at the same time). In univariate analysis, the only significant prognostic factor for disease-free survival was tumor size (p = 0.004). A short Tpot (or high LI) and long overall treatment time (OTT) were weakly associated with poorer disease-free survival, although not statistically significant (1/Tpot, p = 0.14; LI, p = 0.23; OTT, p = 0.04). Age, FIGO stage, hemoglobin level, S-phase fraction, DNA ploidy, and Ts were not associated with disease-free survival. Multiple regression analysis was not performed because of the relatively small number of patients and short follow-up. CONCLUSIONS: Tpot values determined with current techniques by different laboratories cannot be used interchangeably for the purpose of therapy decisions. Vigorous quality assurance and standardization of the laboratory procedures and analysis methods are important to reduce interlaboratory variation. In this uniformly treated group of patients with cancer of the uterine cervix, traditional clinical prognostic factors remain the most important. Preliminary data suggest that the flow cytometry-determined Tpot and labeling index predict for disease-free survival, although a larger number of patients with longer follow-up is required to assess the true prognostic significance of these assays and to determine if their effect is independent of other clinical factors.

Adenocarcinoma↗
PubMed1995

Radiation-induced changes in glomerular and tubular cell kinetics and morphology following irradiation of a single kidney in the pig.

PURPOSE: Radiation-induced changes in glomerular and tubular cell kinetics and morphology following irradiation of a single pig kidney were assessed. METHODS AND MATERIALS: The right kidney of 13 adult female Large White pigs was irradiated with a single dose of 9.8 Gy gamma rays. Animals were serially killed between 2 and 24 weeks postirradiation (PI); 1 h prior to postmortem each pig received 500 mg bromodeoxyuridine (BrdUrd). At postmortem, both kidneys were removed and tissue taken to prepare cell suspensions. The labeling index (LI) of these suspensions was measured using flow cytometry; in vivo BrdUrd incorporation in glomerular and tubular cells was determined immunohistochemically. The kidneys were also assessed histologically. RESULTS: Irradiation of the right kidney alone resulted in a significant increase in renal cell LI in both the irradiated and the contralateral unirradiated kidney within 2 weeks of irradiation; peak values of 1.57 +/- 0.32% and 1.04 +/- 0.13%, respectively, were seen 4 weeks PI, significantly greater (P < 0.001) than the preirradiation value of 0.18 +/- 0.01%. The LI values then declined with time, but remained greater than those seen prior to irradiation. A similar pattern of response was determined from counts of labeled glomerular and tubular cells identified immunohistochemically. The increase in labeled glomerular cells was seen 2 weeks PI, whereas that for the tubular cells did not occur until 4 weeks PI. The irradiated kidney exhibited diffuse, progressive glomerular alterations. In contrast, tubular damage was focal; the irradiated kidney also exhibited a prominent vasculopathy, involving arteriolar and peripheral interlobular artery thickening. The contralateral unirradiated kidney appeared unchanged. CONCLUSION: These findings confirm the hypothesis that the morphologic and kinetic responses observed after irradiation of a single kidney are similar to those observed after irradiation of both kidneys. Renal irradiation results in significant alterations in glomerular and tubular cell proliferation and morphology within 2-4 weeks of irradiation; glomerular changes appear predominant.

Animals↗
PubMed1995

Chromosome abnormalities and p53 expression in a small cell carcinoma of the bladder.

Chromosome studies on a highly malignant tumor, a small cell carcinoma of the bladder (the first to be studied cytogenetically), showed a hypertriploid mainline and a hypertetraploid minor line. Extensive chromosomal rearrangements were present in both lines, some rearranged chromosomes being seen in only one of the lines, while others, derived from chromosomes 6, 9, 11, 13, and 18, were seen in both. Although different giant chromosomes were present in the two lines, they shared a possibly significant common feature: multiple copies of 2q. DNA flow cytometry confirmed that the tumor had a hypertriploid main mode and showed that dysplastic surface epithelium present in the histologic material also had a hypertriploid DNA index. p53 expression in the tumor was demonstrated by flow cytometry.

Carcinoma, Small Cell↗
PubMed1995

p53 status of head and neck cancer: relation to biological characteristics and outcome of radiotherapy.

p53 status was investigated in 99 patients with squamous cell carcinoma of the head and neck region uniformly treated with accelerated radiotherapy and in whom tumour cell proliferation and DNA aneuploidy were assessed using bromodeoxyuridine (BrdUrd) incorporation and flow cytometry (FCM). Seventy-six percent of tumours were immunohistochemically positive for p53 protein, but heterogeneity was noticed both in the percentage of cells positive for p53 and in their level of expression. However, tumours which were either essentially all positive or all negative or showed sporadic positivity for p53 protein showed no differences in their level of aneuploidy, proliferation rate, tissue organisation or outcome with radiotherapy. There was a trend for those p53-positive tumours with the strongest expression to have more DNA aneuploidy and deregulation of proliferation organisation than weaker expressors; but there were no differences in proliferation rate or outcome of radiotherapy. These studies suggest that p53 protein stabilisation as assessed by immunohistochemistry does not have any major relationship with the biological characteristics and outcome of squamous cell cancer treated by accelerated radiotherapy.

Aneuploidy↗
PubMed1995

Development of bioreductive markers for tumour hypoxia.

Hypoxic cells in tumours can be identified by exposing them to an immunologically identifiable 2-nitroimidazole (NITP) with a theophylline substituent which becomes bioreductively metabolised and binds to cellular macromolecules in the absence of oxygen. A range of monoclonal and polyclonal antibodies raised against theophylline or caffeine can identify cells containing bound adducts of NITP, in some cases with higher specificity than the standard product used. An alternative approach utilizes the very high specificity of FITC-avidin as a reagent to detect metabolic binding of a 2-nitroimidazole with a biotinylated side-chain (NIB), with the advantage of a single-step staining protocol. Both proliferating and hypoxic cell populations within tumours can be identified by simultaneous staining for incorporation of NITP and BrdUrd and this has shown that some cells incorporate both markers, suggesting that there is some overlap between the proliferating and hypoxic cell compartments.

Animals↗
PubMed1992

Bioreductive fluorescent markers for hypoxic cells: a study of 2-nitroimidazoles with 1-substituents containing fluorescent, bridgehead-nitrogen, bicyclic systems.

The oxygen-sensitive bioreductive binding of 2-nitroimidazoles labeled with fluorescent side chains has been used to stain hypoxic mammalian cells selectively. Several novel compounds were synthesized with a 1-substituent containing a fluorescent, bicyclic system having a bridgehead-nitrogen atom. Additional amine and secondary alcohol substituents were also included in the link between the fluorophor and the nitroimidazole to improve water solubility. Their ability to discriminate between hypoxic and oxic cells was compared by flow cytometric analysis. A wide range of cellular fluorescence and hypoxic-oxic differentials in fluorescence was observed when compounds with indolizine fluorophors were incubated with cells, and one such compound was considered suitable for further evaluation in vivo. Two compounds with bimane fluorophors gave very little cellular fluorescence when incubated with hypoxic cells.

Animals↗
PubMed1992

Proliferation indices of invasive breast carcinomas after in vivo 5-bromo-2'-deoxyuridine labelling: a flow cytometric study of 75 tumours.

In vivo labelling of human breast tumours with 5-bromo-2'-deoxyuridine and analysis of proliferation by multiparameter flow cytometry is a new tool by which the labelling index, S phase duration (TS) and potential doubling time (Tpot) of the tumour can be estimated. Tumour specimens from 75 patients with invasive breast carcinoma were studied. Six tumours could not be analysed, and the TS and Tpot values could not be calculated for a further 18. The median labelling index (n = 69) was 4.2 per cent. The median TS (n = 51) was 8.7 h and the median Tpot (n = 51) was 8.2 days. The median intra-assay coefficient of variation for determination of the labelling index was 0.29 in five tumours. There were no significant differences in the total labelling index, TS or Tpot when patients were stratified according to lymph node status, tumour size, tumour grade or menopausal status.

Adult↗
PubMed1992

Enhancement of tumor radiosensitivity and reduced hypoxia-dependent binding of a 2-nitroimidazole with normobaric oxygen and carbogen: a therapeutic comparison with skin and kidneys.

To evaluate the therapeutic potential of normobaric oxygen and carbogen as hypoxic-cell sensitizers, both radiosensitization in a mouse mammary carcinoma, mouse skin and kidneys, and the reduction in the proportion of hypoxic tumor cells were quantified in mice breathing air, oxygen, or carbogen. Local tumor control, acute skin reactions, reduced renal clearance, and hematocrit were used as assays. X rays as 10 fractions in 5 days were given to skin and tumors and 10F/12 days to kidneys. In the tumor study, the pre-irradiation breathing time was varied from 2 to 20 min. Hypoxic cells, before and during a 10F/5 day schedule, were quantified using a 2-nitroimidazole with a theophylline side chain. Bioreductively reduced metabolites of this probe were localized in hypoxic cells that were then stained using an immunofluorescent technique and analyzed by flow cytometry. The fraction of cells with high fluorescence intensity was 19% in air, 9% in oxygen, and 3% in carbogen-breathing mice. For all three gases, hypoxia-dependent binding was similar in non-irradiated tumors and those treated with four or nine fractions. Both gases significantly enhanced tumor radiosensitivity (ER = 1.3 to 1.6) and carbogen was slightly more effective than oxygen. With carbogen, maximum sensitization was observed with a 5 min pre-irradiation breathing interval. With oxygen, pre-irradiation breathing times of 2-20 min gave similar sensitization. In skin an enhancement ratio of 1.2 was observed, whereas enhancement ratios for both renal endpoints were significantly lower (1.0 to 1.07). Relative to both tissues, there was therefore a substantial therapeutic gain by irradiating CaNT tumors under both gases, especially with carbogen.

Administration, Inhalation↗
PubMed1992

Tumor cell kinetics, local tumor control, and accelerated radiotherapy: a preliminary report.

The local tumor control achieved in patients treated in a pilot study of continuous, hyperfractionated, accelerated radiotherapy has been related to the tumor cell kinetics evaluated by in vivo administration of bromodeoxyuridine and flow cytometry. In 42 of 50 patients with advanced squamous cell carcinomas in the head and neck region it was possible to sample the primary tumor prior to treatment. In three further cases, involved regional nodes were studied: in the remaining five, tissue was obtained subsequently either from a local recurrence or from a distant metastasis. Successful cell kinetic measurements were made in 38 (90%) of the 42 primary tumors. The median values of the labelling index, the duration of the DNA synthetic phase and, thus, the potential doubling time for all primaries were 7.1%, 9.8 hr, and 3.9 days, respectively. Complete regression was achieved in 28 (74%) of the primary tumors and in 23 (61%) this was maintained to the time of observation for this report. There was no significant influence of any of the cell kinetic parameters upon the immediate or longer term local tumor control. This result is compatible with the overcoming of cellular repopulation by the acceleration of radiotherapy.

Aneuploidy↗
PubMed1992

Flow cytometric characterisation of proliferating cell nuclear antigen using the monoclonal antibody PC10.

Anti-PCNA antibodies have aroused considerable interest recently as potential immunohistochemical markers of proliferation for use on clinical samples. PC10 is a monoclonal antibody which has been shown to recognise its epitope on formalin-fixed, paraffin-embedded, archival material. However, whilst PC10 gives the expected labelling pattern for growth fraction in normal tissues and some tumours, discrepant results have been obtained, for example, in carcinoma of the breast. By means of flow cytometry, we have attempted to characterise the different staining patterns that can be obtained with PC10. Intact fixed cells from proliferative mammalian cultures show 100% labelling, consistent with a growth fraction estimate. In contrast, detergent-extracted nuclei show S-phase specific staining. Nuclei extracted by treatment of fixed cells with pepsin show a different staining pattern again, with many G1 cells weakly stained and staining intensity increasing through S-phase into G2. The results demonstrate that multiparametric flow cytometry can define the cell populations which label with proliferation-related antibodies, such as PC10, under a variety of experimental conditions.

Animals↗
PubMed1992

Tumour proliferation assessed by combined histological and flow cytometric analysis: implications for therapy in squamous cell carcinoma in the head and neck.

The two techniques of flow cytometry analysis (FCM) and immunohistochemical localisation of bromodeoxyuridine (BrdUrd) incorporation after in vivo administration, were combined to study proliferation in squamous cell carcinoma of the head and neck region. Care was taken in this study to ensure that similar material was processed using both techniques such that comparisons could be made. FCM underestimated the labelling index (LI) in tumours classified as diploid compared to the histological evaluation of the tumour cells within those tumours (4.6% vs 17.1%). However, in aneuploid tumours, the FCM LI (10.7%) was similar to that obtained from histology (13.5%). Indeed, proliferation assessed by the combination of histology LI and FCM duration of S-phase (Ts) indicated that diploid tumours had a shorter median potential doubling time (Tpot) of 2.1 days compared to aneuploid (2.8 days). Despite the heterogeneity of proliferation evident histologically within the specimens, there was not a wide variation in the results of FCM analysis when multiple samples from resections were studied. Using FCM data alone, 46% of the tumours showed a Tpot of less than 5 days. When the Ts from the FCM data was combined with the average histological LI, 84% were less than 5 days and with the maximum LI, 99% were within this time interval. Compared with previous estimates, the proportion of tumours possessing proliferative characteristics which may indicate the need for acceleration of treatment seems to be much larger.

Aneuploidy↗
PubMed1992

Performance measures, blood lactate and plasma ammonia as indicators of overwork in elite junior weightlifters.

The effects of short-term overwork on performance measures, blood lactate, and plasma ammonia concentrations were examined in 28 elite junior weightlifters who participated in a 2 wk high volume resistance training camp. Performance testing (maximum effort vertical jump test and snatch lift) and blood chemistry analyses (ammonia and lactate) were conducted before (T1) and after (T2) 7 d of high volume training (2-3 workouts/d). Blood samples were collected from an antecubital vein at rest, preexercise, 5 min postexercise, and 15 min postexercise at T1 and T2. Results indicated a significant decrease from T1 to T2 in the maximum effort vertical jump test while the snatch lift test yielded no difference across time. Blood lactate and ammonia concentrations were significantly lower at 5 min postexercise at T2 while resting ammonia concentrations were significantly elevated at T2 compared to corresponding measures at T1. These data suggest possible early symptoms of overwork at T2 (decrease in performance of the maximum effort vertical jump test and the elevated resting ammonia concentrations); however, lower 5 min postexercise concentrations of lactate and ammonia at T2 indicated a positive adaptation to the 1 wk high volume resistance training period.

Adolescent↗
PubMed1992

Proliferative changes in two murine tumours in response to single or fractionated doses of X-rays.

Studies were carried out to investigate proliferative changes in two murine experimental tumours in response to radiation. Results were generated using bromodeoxyuridine labelling and flow cytometry. This study demonstrates the possible ambiguity of previous studies using tritiated thymidine in which inability to discriminate normal and tumour cell components in murine tumours may lead to different values for cell kinetic parameters. In particular, the sarcoma F appeared to have a growth fraction of 0.62 when all cells were considered; in reality the growth fraction of the tumour cells only (based on DNA content discrimination) was close to unity. Radiation, administered either as single or fractionated doses, caused little change in the proliferative characteristics of the sarcoma F tumour but had profound effects on the adenocarcinoma Rhodesia tumour. Major changes were the accumulation of cells in G2 for several days after the end of the radiation treatment in both tumours and a dramatic drop in labelling index of the Rhodesia tumour. In neither tumour was there any evidence to suggest an increase in tumour cell proliferation during or after the irradiations. The diploid cells within the sarcoma F tumour showed an initial depression of labelling index followed by a rapid increase overshooting the control labelling index at higher radiation doses. Much of the effects could be attributed to cell cycle delays.

Adenocarcinoma↗
PubMed1992

Efficacy of chromium supplementation in athletes: emphasis on anabolism.

As the biologically active component of glucose tolerance factor (GTF), the essential trace mineral chromium is now being marked to athletes. GTF potentiates insulin activity and is responsible for normal insulin function. Thus, insulin's effects on carbohydrate, fat, and protein metabolism are dependent upon the maintenance of adequate chromium stores. Due to excessive chromium loss and marginal chromium intake, athletes may have an increased requirement for chromium. Therefore, in some circumstances the dietary supplementation of a chromium compound may be efficacious. The restoration and maintenance of chromium stores via supplementation would promote optimal insulin efficiency, necessary for high-level athletic performance. However, potential anabolic effects of enhanced insulin function would likely be marginal, and reports of short-term anabolic increases from the supplementation of an organic chromium compound need to be confirmed.

Animals↗
PubMed1992

Measurement of in vivo proliferation in human colorectal mucosa using bromodeoxyuridine.

In vivo bromodeoxyuridine (BrdUrd) labelling of the human large bowel was performed and a detailed histochemical localisation of label in sections of crypts was undertaken using a monoclonal antibody to BrdUrd containing DNA. Flow cytometric studies on extracted nuclei were also performed (data presented elsewhere). The average crypt in the human large bowel (excluding the rectum) was 82 cells in height and 41 cells in circumference, with a total of about 2000 cells (assuming a topographical correction factor of 0.6). Ten per cent of the cells were replicating their DNA--that is, were in the S phase of the cell cycle--and 0.4% were in mitosis. The median position for the labelling index versus cell position frequency plot is at the 20th cell position--at a quarter of the crypt height. The lower and upper limits of the cell proliferation are given by the 5th and 95th percentiles at cell positions 4 and 43 respectively. The peak labelling index is about 30% and it occurs at cell position 15. The labelling index at the crypt base, the probable stem cell zone, is about 14%, suggesting that these cells have a longer cell cycle. Taking a value of 8.6 hours for the duration of the S phase (deduced from the flow cytometric data) and assuming a growth fraction of 1.0 for the mid-crypt, these data provide an estimate of about 30 hours for the cell cycle time. The rectal crypts are about the same size but contain about 30% fewer S phase cells. The data also yielded a per cent BrdUrd labelled mitosis curve.

Aged↗