Biomedical subjects

W M Gray

Publications and source records attributed to W M Gray.

At least 55 records · Page 3Linked to original sources

PubMed1980

The effects of whole-body irradiation on the serum levels and kinetics of thyroid hormones in rats.

The effects of a single whole-body dose of X-rays on the serum levels and kinetics of thyroid hormones in rats were studied. The influence of radiation-induced anorexia was monitored by using pair fed control groups. A dose of 800 rad caused a reduction in T4 levels and 750 rad had a similar effect on T3; in each case the control group showed a smaller reduction. The kinetic results indicated that, in the control groups, the early reduction in hormone concentrations was caused, by a change in the distribution of the hormone; however, the continuing reduction in hormone levels in the irradiated rats appeared to results from decreased production. The results suggest that the thyroid system may play an active part in the early metabolic changes which follow whole-body irradiation.

Animals↗

PubMed1978

The value of provocative and acute urography in patients with intermittent loin pain.

Twenty-two patients with intermittent loin pain thought to be typical of primary pelvic hydronephrosis but with normal appearances at standard excretion urography were subjected to diuretic urography using Frusemide-induced diuresis. If this was normal, acute urography was performed when the patient had pain. Abnormal appearances were shown in only 15 patients. In 4, only the erect films revealed the hydronephrosis. Dilatation occurred in response to a diuretic load in 9 and the abnormality was shown at the time of an attack of pain in 4. The hydronephrosis was shown only during the attack of pain in 2, a diuretic urogram having been normal. In 2 patients the nephrographic signs of acute obstruction were shown to be due to occlusion of the pelvi-ureteric junction at the time of an attack of pain. The importance of sequential examination, the value of erect films and acute urography are stressed.

Diuresis↗

PubMed1977

Cumulative radiation effect. Part VI: simple nomographic and tabular methods for the solution of practical problems.

In five previous papers, the concept of the Cumulative Radiation Effect (CRE) has been presented as a scale of accumulative sub-tolerance radiation damage. The biological effect generated in normal connective tissue by fractionated or continuous radiation therapy given in any temporal arrangement is described by the CRE on a unified scale of assessment, so that a unique value of the CRE describes a specific level of radiation effect. The basic methods of evaluating CREs were shown in these papers to facilitate a full understanding of the fundamental aspects of the CRE-system, but these methods can be time-consuming and tediuous for complex situations. In this paper, simple nomographic and tabular methods for the solution of practical problems are presented. An essential feature of solving a CRE problem is firstly to present it in a concise and readily appreciated form, and, to do this, nomenclature is introduced to describe schedules and regimes as compactly as possible. Simple algebraic equations are derived to describe the CRE achieved by multi-schedule regimes. In these equations, the equivalence conditions existing at the junctions between schedules are not explicit and the equations are based on the CREs of the constituent schedules assessed individually without reference to their context in the regime as a whole. This independent evaluations of CREs for each schedule results in a considerable simplification in the calculation of complex problems. The calculations are further simplified by the use of suitable tables and nomograms, so that the mathematics involved is reduced to simple arithmetical operations which require at the most the use of a slide rule but can be done by hand. The order of procedure in the presentation and calculation of CRE problems can be summarised in an evaluation procedure sheet. The resulting simple methods for solving practical problems of any complexity on the CRE-system are demonstrated by a number of examples.

Connective Tissue↗

PubMed1977

Cumulative radiation effect. Part VII: computer calculations and applications in clinical practice.

In five previous papers, the concept of the Cumulative Radiation Effect (CRE) has been presented as a scale of accumulative sub-tolerance radiation damage. The biological effect generated in normal connective tissue by fractionated or continuous radiation therapy given in any temporal arrangement is described by the CRE on a unified scale of assessment, so that a unique value of the CRE describes a specific level of radiation effect. The basic methods of evaluating CREs were shown in the papers to facilitate a full understanding of the fundamental aspects of the CRE-system, but these methods can be time-consuming and tedious for complex situations. In the previous papers in this series, one way of overcoming the difficulties in evaluating CRE problems was presented in simple nomographic and tabular methods for the solution of practical problems. An alternative way of overcoming the difficulties in the evaluation of CRE problems is to use computers and it is the purpose of this paper to outline computer calculations and applications in clinical practice in connection with the CRE-system. In a general appraisal of the applications of computers to the CRE-system, the various problems encountered in clinical radiotherapy are categorised into those involving the evaluation of a CRE at a point in tissue and those involving the calculation of CRE distributions. As a general guide, the computer techniques adopted at the Glasgow Institute of Radiotherapeutics for the solution of CRE problems are presented, and consist basically of a package of three interactive programs for point CRE calculations and a Fortan program which calculates CRE distributions for iso-effect treatment planning. Many examples are given to demonstrate the applications of these programs, and special emphasis has been laid on the problem of treating a point in tissue with different doses per fraction on alternate treatment days. The wide range of possible clinical applications of the CRE-system has been outlined and described under the categories of routine clinical applicatons, retrospective and prospective surveys of patient treatment, and experimental and theoretical research. Some of these applications such as the results of surveys and studies of time optimisation of treatment schedules could have far-reaching consequences and lead to significant improvements in treatment and cure rates with the minimum damage to normal tissue.

Computers↗

PubMed1976

Metastatic Crohn's disease.

Metastatic Crohn's disease is a term used to describe a granulomatous reaction occurring in flexures, and separated from the affected areas of the gastro-intestinal tract by normal skin. Previous reports refer to such lesions affecting the groins, the male genitalia, a flexure on the anterior abdominal wall of an obese patient, and submammary regions. A further case, in which the retro-auricular areas are involved, is presented.

Adult↗

PubMed1976

Characteristics of bacteria isolated by the anaerobic roll-tube method from cheeses and ground beef.

In this study the methods of Hungate were used to quantitate the anaerobic bacteria present in commercially available ground beef, cheddar cheese, and German hand cheese. Of 235 anaerobic roll-tube isolates from ground beef and German hand cheese, all were facultative anaerobes. Of 213 anaerobic roll-tube isolates from cheddar cheese, 91% were facultative anaerobes and 9% were obligate anaerobes. Using results of biochemical tests, 14 or the 17 obligately anaerobic isolates from cheddar cheese were Propionibacterium acnes, two were strains of Propionibacterium that could not be speciated, and one was tentatively identified as a strain of Streptococcus evolutus. Obligate anaerobes were estimated to be present in the cheddar cheese at a level of about 10(6)/g. The possible significance of these levels of P. acnes in nonsterile foods is discussed.

Anaerobiosis↗

PubMed1975

Cumulative radiation effect. part IV. Normalisation of fractionated and continuous therapy - area and volume correction factors.

In three previous papers, a scale of accumulated sub-tolerance radiation damage, the Cumulative Radiation Effect (CRE), was described for fractionated treatment regimes and continuous radiation therapy from both long-lived and short-lived sources. This scale provides a means of assessing and comparing the biological effects of various treatments. In this paper, it is intended to further the scope of application of the CRE-system by describing in detail the normalisation between the assessments of fractionated and continuous therapy. To do this, it is necessary to consider area and volume correction factors, whose roles are to modify the values of uncorrected CREs so that a specific biological effect, regardless of the area or volume treated, is described by a unique value of the corrected CRE. The problem arising when the CRE achieved by a treatment regime is not constant over a volume is briefly discussed and a simple hypothesis is proposed which may stimulate interest in this problem. The establishment of a normalisation procedure between fractionated treatment regimes and continuous radiation therapy, which is the primary aim of this paper, serves to integrate the concept of the CRE into a unified system of assessment of biological damage, so that a unique value of the CRE describes a specific level of biological damage regardless of the area or volume treated, or the time course of administration of the radiation employed.

Dose-Response Relationship, Radiation↗

PubMed1973