Search

The classical literature shows that wasting of body protein takes place mainly from the cellular compartment leaving high proportions of extracellular collagen. Whole body nitrogen ( WBN ) is proportional to whole body protein (cellular + extracellular) while whole body potassium ( WBK ) is almost entirely intracellular. WBK might be an adequate index of cellular wasting. WBN was measured by neutron activation and WBK by counting 40K in 29 healthy males and 131 male and female patients with wide ranges of body composition. Our wasted patients with Crohn's disease or ulcerative colitis, had higher WBN / WBK ratios than matched healthy controls and the difference between the two groups was in the cellular ratio (23.6 mol of N/mol of K, 0.33 g of N/mmol of K, 3 mmol of K/g of N). A multiple regression model for all the subjects represented cellular nitrogen by a term in WBK and extracellular nitrogen by simple anthropometric measurements. The partial regression coefficient of WBN on WBK was 22.6 +/- 1.1 (SE) mol of N/mol of K; this was also similar to the cellular ratio. Our results were compatible with extracellular protein (mainly collagen, which is 35% of normal whole body protein) remaining resistant to wasting even when severe loss of cellular protein occurs. The high ratios of WBN / WBK in wasted patients can be explained by this disproportionate wasting of cellular substances and they do not imply alterations in the cellular N/K ratio. We suggested that the stable ratio of WBK to cellular protein makes it an effective index of cellular wasting. The resistance of collagen to wasting and the preponderance of extracellular mass in the fat-free mass of wasted subjects, make WBN and fat-free mass unreliable guides to the extent of wasting.

Interference by tribothermoluminescence and by regeneration thermoluminescence can be eliminated for burned flint if thin polished slices are used instead of the powders conventionally used in thermoluminescent measurements. Measurement of the internal and external radiation dose rates then makes possible the absolute determination of the date of pyrolization of small fragments of chert or chalcedony to an accuracy of about 10 to 15 percent. The method may be usable to ages in the range from 200,000 to 300,000 years before the present (B.P.). For samples from the archeological site at Carigüela in southern Spain dates from 12,000 to 50,000 years B.P. have been determined, covering deposits ranging from Late Paleolithic-Epipaleolithic to Mousterian. One Bronze Age specimen gave an age of 4,300 years B.P., in excellent agreement with the age determined by other methods.

An investigation has been made of some physiological problems associated with the interpretation of in-vivo measurements of calcium by the argon-37 method. Inert-gas elimination in humans over a period of several days was studied using i.v. injections of Xe-133. The results imply that the exhalation rate of A-37 formed in bone will be affected by the individual's composition, in particular body fat. Comparison of calcium measurements between individuals and between laboratories is meaningful only if corrections are made for differing individual composition.

Neutron capture gamma-ray analysis has been applied to the in vivo detection of Cd in man. The technique was designed for the screening of industrial workers at risk. The limit of sensitivity in a liver-sized phantom is 0-5 ppm for a dose of 0-4 rad. Reproducibility and the effects of positional uncertainties have been investigated. A number of cadavers were studied to establish normal limits prior to commencement of a programme of clinical investigation. A patient with known Cd poisoning was estimated to contain 65-110 ppm of Cd in his liver. A liver dose of 0-05 rad was required.

Serial measurements of whole body potassium and whole body nitrogen were carried out in 18 newly diagnosed diabetcs. Initial measurements were made before treatment of diabetes was commenced, and further measurements were carried out following the start of treatment. Six patients required insulin and the remainder were treated either with diet alone (four cases) or with diet and oral hypoglycaemic agents. Significant increases in whole body potassium and whole body nitrogen were noted following control of diabetes.Thesees. These changes were most marked in the patients treated with insulin. The techniques used for measurement of body potassium and nitrogen offer considerable advantages over conventional metabolic balance studies and the results indicate that the losses of potassium and nitrogen during period of poor diabetic control are much greater than that has been realized.

Films made from cellulose nitrate LR-115 (Pathé Kodak) and CR-39 have been used for long-term measurements of the radon-222 emanation from building materials and the resultant activity inside houses. The emanation from crushed granite bricks is found to be produced from within the brick while in the clay bricks it originates in the surface layers only. The airborne radon activity inside houses constructed from clay brick is found on average to be 22 mBq 1-1 (0.57 pCi 1-1) while inside a closed vessel sealed to the brick the average equilibrium activity is 40 mBq 1-1 pCi 1-1).

A new, rapid, non-invasive technique for measuring tissue-cadmium concentrations in patients and industrial workers has been designed and developed with a view to studying the cadmium content of the liver. The method utilises the principle of neutron-activation analysis whereby the specific changes produced by the inter action of nuclei and neutrons are analysed. Liver-cadmium content has been studied in cadavers and in four men with known of suspected cadmium poisoning. The patients all showed very high liver-cadmium levels of between 35 and 200 p.p.m. compared with under 1.0 p.p.m. in non-exposed subjects. The dose of radiation used in clinical studies was 0.4-1.0 rem and the detection limit of cadmium was 1.0 p.p.m.

Man has multiplied and become civilised by changing his environment to suit himself, especially by the development of agriculture. The near-elimination of infectious diseases among the young and middle-aged has increased the cancer death rates in Britain, which mainly affect the elderly, to 130 000 a year. A large proportion of cancers are initiated by environmental factors which should be discoverable and removable. Natural radon may be responsible for up to 400 cancer deaths annually and radiation from the nuclear industry for one or two more. An important number of cancers must be due to air pollution from the burning of coal and oil, which are also injuring the wildlife of the northern hemisphere and which, by increasing the concentration of carbon dioxide in the air, may be changing the climate of the whole planet.

Most types of paint for the internal walls of houses will reduce radon emanation from building materials. At the same time, the effect of paint will increase the concentration of radon inside the material itself and will increase the radon emanation from unpainted areas. One type of wall paper contains 6 and 0.3 ppm of uranium in its decorated and undecorated surfaces, respectively, the colouring being the main source of uranium. Other wallpapers appear to be free from uranium. Wallpaper, gypsum and plaster may increase the radon activity inside houses depending on their radium contents.

A study has been made of the effect that different methods of breath collection have on the measurement of calcium in vivo by the 40Ca(n,alpha) 37Ar method. The effect of open and rebreathing breath collection methods has been examined by using intravenous injections of 133Xe. This study has indicated that comparison of calcium measurements between individuals and between centres is likely to be accurate only if breath is collected on 'open circuit'.

A technique has been developed to measure lead content in teeth using 3He2+ activation analysis. The alpha-activity produced in the teeth is recorded on plastic film alpha-track detectors (LR-115) and compared to the activity produced by the lead contained in standard glass. The concentration in teeth from three areas of the United Kingdom has been determined as a function of age. The lead content is found to increase with age in dentine and pulpal dentine, but not in enamel.

The threshold foil technique has been used to investigate the behaviour in tissue of the spectra of neutron beams produced by the bombardment of thick Be targets with 13-0 and 20-5 MeV deuterons. The results indicate a gradual "softening" with depth in tissue of the spectrum generated by 20-5 MeV deutrons which contrasts with a gradual hardening as reported by other authors. This is discussed in terms of the significance of field size and the methods used for data collection and analysis.

Serial measurements were made of total body calcium and sodium, using whole body neutron activation analysis, in six patients being treated for osteomalacia. All showed a rise in total body calcium ranging from 3 to 30%; this continued for up to 24 months after the start of treatment, though complete healing had apparently occurred after 6 months on the basis of histological examination of biopsy specimens of bone. As the total body calcium rose there was a fall in the non-exchangeable sodium pool in bone.