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Biomedical subjects

G D Wilson

Publications and source records attributed to G D Wilson.

At least 127 records · Page 7Linked to original sources
PubMed1989

Human reactions to reward and punishment: a questionnaire examination of Gray's personality theory.

The development of the Gray-Wilson Personality Questionnaire is described; this is an instrument designed to measure human equivalents of six animal behaviour paradigms--Approach, Active Avoidance, Passive Avoidance, Extinction, Fight and Flight. Although these six scales showed satisfactory internal consistency they failed to link up into the three major systems suggested by Gray's personality theory. The strongest associations were between Fight and Approach and between Flight and Passive Avoidance. This raises questions as to how the neurological systems of activation, inhibition and fight/flight are related to human personality structure.

Adult↗
PubMed1989

The effect of the squat exercise on knee stability.

Past studies have produced conflicting results as to the effect of squat exercises on knee stability. One hundred male and female college students were measured using a knee ligament arthrometer on nine tests of knee stability. Over an 8-wk training program, full or half squats did not consistently affect knee stability compared to non-squatting controls. To measure the effect of long-term squat training 27 male powerlifters (14 Elite or Master Class) and 28 male weightlifters (8 Elite or Master Class) were measured on the same tests. Powerlifters were significantly tighter than controls on the anterior drawer at 90 degrees of knee flexion. Both powerlifters and weightlifters were significantly tighter than controls on the quadriceps active drawer at 90 degrees of knee flexion. Data on powerlifters and weightlifters were also analyzed by years of experience and skill level. No effect of squat training on knee stability was demonstrated in any of the groups tested.

Athletic Injuries↗
PubMed1988

Cell kinetics of human brain tumors: in vivo study with bromodeoxyuridine and flow cytometry.

Bromodeoxyuridine (BUDR) is a thymidine analog which is incorporated into the DNA of proliferating cells. Since the dose of BUDR needed to label cells is not toxic, cell labelling can be accomplished in vivo, by infusing the substance in patients. A monoclonal antibody against BUDR is then used to identify BUDR-labelled cells. The same cell population can also be stained for DNA content with propidium iodide (PI). Using bivariate flow cytometry (FCM) for measurements, both the percentage of BUDR-labelled cells and their total DNA content can be evaluated. This technique allows one to obtain the labelling index (LI) and the DNA synthesis time (TS). The potential doubling time (Tpot) and the fractional turnover rate (FTR) can be mathematically derived, so that a complete picture of tumor growth can be obtained. Our aim was to ascertain whether this method is clinically applicable and whether the kinetic values obtained are reliable. We studied 22 patients with benign and malignant brain tumors, and observed no immediate toxicity from BUDR administration. The BUDRLI obtained ranged from 0.9% to 3.9% (median: 2.0%) in meningiomas and from 3.8% to 7.6% (median: 6.3%) in malignant gliomas (P less than 0.01). The fraction of S-phase cells determined with the BUDR FCM technique was statistically similar to that found by single DNA flow cytometric analysis performed on duplicate samples of both benign and malignant brain tumors. The TS obtained in malignant gliomas ranged from 10.5 to 227 h (median: 12.8). The calculated Tpot ranged from 7.6 to 26.8 days (median: 11.6), and the calculated FTR ranged from 3.7 to 13.1 cells/100 cells/day (median: 8.8). These data suggest that in vivo BUDR infusion coupled with FCM can be performed in clinical settings, and it is reliable and can easily be used for kinetic studies in clinical trials aimed at evaluating the prognostic relevance of proliferative parameters and in planning tumor treatment.

Adult↗
PubMed1988

Measurement of cell kinetics in human tumours in vivo using bromodeoxyuridine incorporation and flow cytometry.

The proliferative potential of human solid tumours, in vivo, was investigated using bromodeoxyuridine (BrdUrd) incorporation and flow cytometry (FCM). Patients with solid tumours from a variety of sites were injected with 500 mg BrdUrd, intravenously, several hours prior to biopsy or surgical excision. The labelling index (LI), duration of S-phase (Ts) and thus the potential doubling time (Tpot) could be measured within 24 h of sampling. The results show that both the LI and Ts vary greatly between tumours (Ts ranges from 5.8 to 30.7 h). However, within this study of 26 evaluable patients, tumours of the same tissue origin tended to have similar Ts values. Melanomas had the shortest Ts (8.8 h), nine patients with head and neck cancer had Ts values ranging from 5.8 to 18.8 h (median 12.5 h). The longest Ts values (24 h) were found in lung and rectum. The estimates of Tpot ranged from only 3.2 days in an oat cell carcinoma to 23.2 days in a lymphoma. The striking feature of the study was that 38% of the tumours had a potential doubling time of 5 days or less. We found no relationship between proliferation and histopathological differentiation or DNA ploidy. It should now be possible to assess the prognostic significance of pretreatment cell kinetic measurements which may, in the future, aid in the selection of treatment schedules for the individual patient.

Bromodeoxyuridine↗
PubMed1988

Flow cytometric evaluation of the effects of 2.3 MeV neutrons and 240 kV X rays on mouse spermatogenic S-phase cells using bromodeoxyuridine incorporation.

A sensitive flow cytometric assay has been developed to assess the effect of X rays or neutrons on the DNA-synthesizing ability of mouse testis cells. The dose to reduce the labelling index (LI) to 50% (ED50) was 25 cGy for X rays and 5 cGy for neutrons, giving a relative biological effectiveness (RBE) of 5.0. A significant reduction of the LI was seen at X-ray doses as low as 10 cGy. Neutron treatment resulted in an exponential decrease in functional S-phase cells while the X-ray response was biphasic. The sensitivity and rapidity of the assay would be suitable for use in biological dosimetry.

Animals↗
PubMed1987

Cell kinetics of mouse kidney using bromodeoxyuridine incorporation and flow cytometry: preparation and staining.

The kidney is recognized as a dose-limiting tissue by certain radiation treatments. The relationship between the onset of compensatory proliferation in response to irradiation and the expression of functional damage is difficult to study because of the low cell turnover in slowly proliferating tissues. We report on a method to obtain a suitable cell preparation from mouse kidney for study by flow cytometry using the recently developed staining techniques for bromodeoxyuridine incorporation. The labelling index of 0.3% in untreated mouse kidney was easily measured because large numbers of cells could be analysed rapidly. We show that compensatory proliferation after unilateral nephrectomy remains elevated for up to 3 weeks after surgery. Using the BrdU/FCM technique we were able to measure the duration of the S phase in normal and nephrectomized kidneys which we found to be 8.5 hr in both cases. The estimates of potential doubling time were similar to the time scale observed to elapse before functional damage is observed in normal kidneys and those in which damage is precipitated by surgery.

Animals↗
PubMed1986

Cell kinetics of normal and perturbed populations measured by incorporation of bromodeoxyuridine and flow cytometry.

Bromodeoxyuridine (BrdU) incorporation and flow cytometry have been used to measure the kinetics of V79 cells growing at different temperatures in vitro and cells of the murine Sa F tumour growing in vivo. By simultaneously measuring total DNA content and BrdU incorporation in individual cells at different times after pulse labelling with BrdU, it is a simple procedure to quantify the movement of cells through the cell cycle. The method has the advantage of speed (2 X 10(4) or more cells are analysed within a day or so of the experiment) and the ability to analyse the results in different ways. A G2 block in tumour cell progression in vivo is readily detected after a dose as low as 2 Gy. The neutron relative biological effectiveness for this G2 block is probably larger than that for tumour growth delay.

Animals↗
PubMed1986

Dietary fat and cancer: a perspective from the livestock and meat industry.

It has been a popular belief that U.S. consumers ingest approximately 40% of their calories as fat and that a high percentage is from animal sources. In fact, animal fat consumption has declined 23% in the past 20 years and the increase in fat consumption has been solely due to vegetable (plant) sources. The decline in animal fat production probably explains why the estimates discussed in this presentation fall below earlier literature references. The validity of the estimates presented here will be determined as part of an in depth study undertaken by the National Academy of Sciences' Board of Agriculture. If this comprehensive study substantiates the values presented in this paper and other recent publications, a reconsideration of the impact of animal source fats on caloric intake and diet related diseases is indicated. The U.S. livestock and meat industry is extremely aware of and responsive to the role of meat and meat products in the nutrition, health and well-being of the nation. Research programs are designed with these factors as a guide and producers continue to adjust product characteristics to meet the changing needs.

Agriculture↗
PubMed1985

The labelling index of human and mouse tumours assessed by bromodeoxyuridine staining in vitro and in vivo and flow cytometry.

Bromodeoxyuridine (BrdUrd) incorporation and flow cytometry were used to measure human tumour kinetic parameters in vitro and in vivo. The technique was validated by comparison of labelling index estimates of mouse tumours in vivo and in vitro using BrdUrd and flow cytometry with tritiated thymidine (3HdThd) autoradiography. Similar labelling indices were obtained with both in vivo and in vitro incorporation into DNA of the two different precursors. Measurements of human tumour labelling indices were similar following in vitro incubation with either BrdUrd or 3HdThd. The use of BrdUrd allowed the visualization of a population of S-phase cells that did not appear to incorporate BrdUrd or 3HdThd. The human tumour labelling indices obtained with BrdUrd incorporation were similar to previously reported values using autoradiography studies. Preliminary studies demonstrated that significant human tumour labelling could be achieved with an intravenous injection of 500 mg BrdUrd.

Animals↗
PubMed1985

Resistive training and selected effects.

This article has briefly discussed the various modes and methods of resistive training, and their relative values and effectiveness in achieving desired goals. Evidence has been presented indicating that resistive training can enhance both "physical and emotional fitness as well as reduce some cardiovascular disease risk factors." This may allow a greater satisfaction and enjoyment in daily activities as well as improve athletic performance.

Animals↗
PubMed1985

Selective toxicity of 1-naphthol to human colorectal tumour tissue.

1-Naphthol was selectively toxic to human colorectal tumours compared to corresponding normal colonic tissue removed at surgery and maintained in short-term organ culture. Nineteen of 24 tumours studied have shown a significant differential response. Three human colonic adenocarcinoma xenografts, in the short-term organ culture system, displayed the same response to 1-naphthol as primary tumours removed at surgery. 1-Naphthol, 1,2- and 1,4-naphthoquinone were also toxic to two human colonic adenocarcinoma cell lines, LoVo and COLO 206. The selective toxicity of 1-naphthol is mediated in part through an accumulation of 1-naphthol in the tumour tissue due to impaired conjugation by the tumour. The higher concentrations of 1-naphthol may then exert their toxicity either directly or by formation of naphthoquinones. Some indirect evidence was obtained for the possible involvement of 1,2- or 1,4-naphthoquinone in the cytotoxicity of 1-naphthol. Our studies suggest that further studies are warranted of the possible use of 1-naphthol or related compounds as antitumour agents.

Cell Line↗
PubMed1983

Social and psychological factors in the distribution of STD in male clinic attenders. I Demographic and social factors.

We describe three related studies of possible aetiological risk factors for sexually transmitted diseases (STDs) in men attending an STD clinic. In this paper we present the results for a variety of social and demographic variables traditionally associated with STD. In contrast to the results in the next two papers, these were largely negative. Occurrence rates of overall STD or of hepatitis, syphilis, gonorrhoea, or non-specific urethritis (NSU) had no aetiologically relevant association with age, nationality, marital status, social class, occupation, non-sexual social contact, drug abuse, or aggressive attitudes and behaviour. Gonorrhoea, however, was the only STD which correlated with alcohol abuse and with eating out rather than at home. We conclude that, with the possible exception of gonorrhoea, social factors contribute little to the distribution of STD risk within the study population.

Age Factors↗