Quantitative Risk Assessment: State-of-the-Art for Carcinogenesis

Quantitative Risk Assessment: State-of-the-art for Carcinogenesis.Park, C.N. and Snee, R.D. (1983). Fundam. Appl Toxicol. 3: 320–333.A critical evaluation of the use of statistical models in carcinogenicrisk assessment is made with emphasis on the strengths and weaknessesof current practice. The objective is to bring together informationfrom the fields of toxicology and statistics to develop a soundscientific basis for making risk decisions. It is emphasizedthat risk assessment is a complex, multifaceted process thatis not easily quantified and, at present, must be based on qualitativeas well as quantitative information. It is evident that dose-responsemodeling of tumor incidence data from animal studies is of limitedvalue in estimating human risk associated with low-dose chemicalexposures. The models take into account only one part of thecomplex process and have no accepted basis in biology. The keydecision points, qualitative factors, and quantitative considerationsare identified and discussed and a risk assessment frameworkthat incorporates these inputs is presented. A model that incorporatesthe tumorigenic dose-response information as well as the qualitativeand quantitative biological factors that affect the estimateof risk is proposed. It is concluded that much work needs tobe done before a completely quantitative approach to risk assessmentis to be useful; in particular pharmacokinetic modeling shouldbe pursued more aggressively.     

The supervision of mentally disordered offenders: the work of probation officers and their relationship with psychiatrists in England and Wales

This article presents data from a study which has provided evidence of probation officers’ close involvement with some of the most hard to help psychiatric patients and of the nature of their working relations with psychiatrists. Given the burden of responsibility they carry, and the training deficiencies they report, it is clear that probation officers could work more confidently and effectively in this field if there were more opportunities for consultation and shared working with the psychiatric services. We conclude with some suggestions for improving collaboration between psychiatrists and probation officers.     

LONG OESOPHAGEAL MYOTOMY FOR DIFFUSE SPASM OF THE OESOPHAGUS

The symptoms of chest pain and dysphagia together with the typical radiological features of non-peristaltic segmental oesophageal contractions allowed the diagnosis of diffuse oesophageal spasm to be made in ten patients at The Prince Charles Hospital over the last six years. Eight patients have undergone long oesophageal myotomy with sparing of the lower oesophageal sphincter. All patients had immediate postoperative relief of symptoms, with postoperative cine radiographic examination in all patients demonstrating an inert oesophagus with adequate drainage and no gastro-oesophageal reflux. Two patients subsequently developed progressive dysphagia, one requiring a modified Heller's procedure. Because of the good result in six patients, sparing of the lower oesophageal sphincter with long oesophageal myotomy is recommended.     

Reviewing birthweight standards

Summary. The standardization of birthweight for gestational age, taking into accounhd sex of infant and maternal height and weight, is clinically useful and essential for some research purposes. In Britain, the most commonly used standards for singletons are those derived from Thomson et al . (1968) from a series of births to women in Aberdeen between 1948 and 1964. The present study starts with the observation that the present population of births in Aberdeen is different. This prompted work to 'update' the standards at least for research purposes, and in so doing a number of problems have been encountered which complicate the task of developing universally applicable standards.     

Outcome of Alcoholism: the structure of patient attributions as to what causes change

Various strands of the research literature which have bearing on the concept of attribution for change in drinking behaviour are reviewed. The reasons which subjects give for amelioration in their drinking are likely to reflect a mixture of the way in which change is being subjectively construed together with report on the influences and processes which may objectively contribute to change. We present data on such attributions as given by 66 alcoholics on whom we have detailed 10-year information on multiple aspects of outcome and who also completed a 70-item Attributions Inventory. A factor analysis of the Attributions data reveals two factors which have been labelled respectively ‘Active’ and ‘Responsive’, and it is suggested that this may be a more appropriate analytical framework than the single dimension of Internal/External locus of control. The relationship between Attribution factors on the one hand and Outcome components and clusters on the other, is explored.‘Active’ Attribution is significantly and positively related to better ‘High Dependence’ Outcome, whereas ‘Responsive’ Attribution relates significantly and positively to better ‘Low Dependence’ outcome. Potential theoretical and clinical implications are discussed.     

Useful Lessons from Body Surface Mapping

Useful Lessons from Body Surface Mapping. Body surface potential maps (BSMs) depict the time varying distribution of cardiac potentials on the entire surface of the torso. Hundreds of studies have shown that BSMs contain more diagnostic and prognostic information than can he elicited from the 12-lead ECG. Despite these advantages, body surface mapping has not become a routinely used clinical method. One reason is that visual examination and sophisticated analysis of BSMs do not permit inferring the sequence of excitation and repolarization in the heart with a sufficient degree of certainty and detail. These limitations can be partially overcome by implementing inverse procedures that reconstruct epicardial potentials, isochrones, and ECGs from body surface measurements. Furthermore, ongoing experimental work and simulation studies show that a great deal of information about intramural events can he elicited from measured or reconstructed epicardial potential distributions. Interpreting epicardial data in terms of deep activity requires extensive knowledge of the architecture of myocardial fibers, their anisotropic properties, and the role of rotational anisotropy in affecting propagation and the associated potential fields.     

An in-vivo study of renal cadmium and hypertension

Abstract. A comparative study of renal cadmium burdens in a group of thirty hypertensive patients undergoing treatment and in a group of thirty matched controls is reported, both groups being volunteers selected from a non-occupationally exposed population. The aim of this study was to investigate the possible involvement of cadmium in the aetiology of hypertension at the chronic low levels of environmental exposure. Renal cadmium levels were measured in vivo , using the technique of partial-body neutron activation analysis. The results showed that the mean renal cadmium level in the hypertensive group [3-3 mg (SD 2–3)], was not significantly different from that [4-4 mg (SD 2–7)], in the normotensive group. Whether the level in the hypertensives depends on the treatment is open to question and will be the subject of further investigation. In addition, the results confirm that kidney cadmium levels are elevated in smokers.