[Influence of computed tomography on diagnosis cost in renal tumoral syndromes (author's transl)]

The cost of computed tomography has been compared with that of other exploratory procedures in two groups of patients with renal tumoral syndromes. Reduced duration of stay in hospital and reduced number of arteriographies in cases of renal cancer, much lesser use of diagnostic puncture-aspiration in cases of renal cysts are the most obvious benefits of the new method.

Computed tomography diagnosis of renal angiomyolipoma

Six computed tomography examinations were performed on four patients: two of them had tuberous sclerosis, and the other two had solitary angiomyolipomas. Computed tomography is an easy way of diagnosing tumoral hemorrhages and thus facilitates the supervision of patients with tuberous sclerosis. In two patients, the authors observed dense masses that might have indicated cartilage deposits.

Sex differences in the inheritance of some anthropometric characters in twins

Biometrical genetical techniques have been applied to the analysis of certain anthropometric characters measured in 134 pairs of adult twins. After allowing for assortative mating it appears that there is a family environment (E2) component for variation in height larger than previously reported. "Fatness" traits - weight, ponderal index, and skinfold thickness - all show higher heritabilities in males and substantial E2 components in females, and reasons for this are discussed. The same is true for cephalic index and forearm length but the reason for these differences is not so obvious. Head length shows a much higher heritability than head breadth. A larger sample of DZ opposite-sex pairs would allow more powerful discrimination, but the variety of patterns of variation revealed by the model-fitting approach used here justify its use over more traditional techniques.

The genetical relationship of impulsiveness and sensation seeking to Eysenck's personality dimensions

The genetical analysis of covariance structures is used to explore the genetical and environmental intercorrelations of impulsiveness and sensation seeking factors and their conformity to Eysenck's principal personality dimensions. The independent dimensions of psychoticism, extraversion, neuroticism, and lie scale are not found to give a very satisfactory account of the genetical factor structure. In particular, it is clear that impulsiveness and sensation seeking are not simple reflections of extraversion.

Model-fitting approaches to the analysis of human behaviour

Model-fitting methods are now prominent in the analysis of human behavioural variation. Various ways of specifying models have been proposed. These are identical in their simplest form but differ in the emphasis given to more subtle sources of variation. The biometrical genetical approach allows flexibility in the specification of non-additive factors. Given additivity, the approach of path analysis may be used to specify several environmental models in the presence of assortative mating. In many cases the methods should yield identical conclusions. Several statistical methods have been proposed for parameter estimation and hypothesis testing. The most suitable rely on the method of maximum likelihood for the estimation of variance and covariance components. Any multifactorial model can be formulated in these terms. The choice of method will depend chiefly on the design of the experiment and the ease with which a data summary can be obtained without significant loss of information. Examples are given in which the causes of variation show different degrees of detectable complexity. A variety of experimental designs yield behavioural data which illustrate the contribution of additive and non-additive genetical effects, the mating system, sibling and cultural effects, the interaction of genetical effects with age and sex. The discrimination between alternative hypotheses is often difficult. The extension of the approach to the analysis of multiple measurements and discontinuous traits is considered.

Hyperprolactinaemia and impotence

Clinical, laboratory and radiological findings were evaluated in twenty-nine men who had raised serum prolactin concentrations and pituitary tumours. Twenty-one had functionless pituitary tumours ('prolactinomas') and eight had acromegaly. Supraseller extension was detected in twenty of the twenty-six men who had lumbar airencephalography. Three patients were studied before, sixteen before and after and ten only after pituitary ablative therapy. Seventeen of these men complained of complete lack of libido and impotence and six had impaired libido and sexual potency; only six patients in this series denied reproductive symptoms. Thirteen of the impotent subjects had small soft testes, ten reduced facial and body hair and three had marked gynaecomastia. No features of hypogonadism were noted in the six patients without reproductive symptoms and none of the patients had galactorrhoea. Serum prolactin concentrations were higher and serum testosterone concentrations lower in the impotent men compared with those with normal sexual potency. Serum LH and FSH (both basal and in response to LHRH) oestradiol and oestrone concentrations were not different between the two groups and, except in those with post-operative hypopituitarism, were within the normal range. Following successful lowering of prolactin concentrations by surgery or bromocripitine or both, serum testosterone rose and potency returned; by contrast failure to lower prolactin concentrations was associated with persistent impotence and hypogonadism. The endocrine profile of low serum testosterone concentrations with gonadotrophins which had not risen into the range usually seen in primary hypogonadism (together with the parallel increase of LH and testosterone in one patient studied sequentially during treatment which suppressed prolactin levels to normal), suggested that the impaired gonadal function was caused by a prolactin-mediated disturbance of hypothalamic-pituitary function.

[Synchronous growth in liquid medium of species related to "Mycobacterium rhodochrous": "Nocardia restricta" and "Jensenia canicruria" (author's transl)]

The synchronous development of nocardioform and coryneform populations had not yet been studied. We have observed that it is possible to obtain a synchronous growth of Nocardia restricta and Jensenia canicruria (species related to Mycobacterium rhodochrous) in a liquid synthetic medium by inoculating the medium with spherical cells taken during the advanced stationary phase, at the end of the cell division cycle. Good synchrony produces a series of breaks in the slope of culture absorbance and of cell protein content. DNA replication checked either by cell DNA content measurements or by pulse-incorporations of tritiated thymidine, is discontinous; peaks of incorporation of thymidine follow one another with a periodicity equal to the generation time. A study of the cell division cycle, hitherto unknown, is now possible.

[Health services priorities in Quebec]

The reform of health services in Quebec, of which the most important stage was the creation of the Department of Social Affairs and the Quebec Health Insurance Board, has solved certain problems such as the inaccessibility to care because of the cost, the paucity of medical personnel and the excessive increase in the cost of the services offered to hospital patients. A critical analysis of both the reform and its practical consequences points to certain conclusions which, far from rejecting the principle of the reform, indicate none the less various possibilities for reorienting its priorities. Observing the rate of recourse to health services as well as the attitudes and conduct of health professionals have helped us to identify the causes of certain tendencies inspired by the incentives inherent in the reform. The organization of health services in Quebec must be oriented toward new priorities: the prevention and treatment both of environmental diseases and diseases associated with ageing plus the definition of a global approach to public health.

The genetical analysis of covariance structure

The analysis of covariance structures (Jöreskog, 1973) is adapted to the simultaneous maximum likelihood estimation of genetical and environmental factor loadings and specific variances. The goodness of fit is tested by chi square and standard errors of parameter estimates can be obtained. Any linear model used in univariate genetical analyses can be extended to the multivariate case. Most biological hypotheses about the relationships between variables can be specified by a variety of factor models. Individual parameters can be given fixed values or set to zero and hypotheses concerning the congruence of genetical and environmental correlations can be tested. The method is illustrated with published twin data on cognitive abilities.

Genetical, environmental and personality factors influencing the age of first sexual intercourse in twins

A study of MZ and DZ twins suggests that cultural differences are less important than individual environmental experiences in determining the age of first sexual intercourse. Certain personality factors are found to be correlated with this trait and there is also evidence that genetical differences may predispose individuals to cross this threshold at an earlier or a later age.