1538

acknowledges that smoking prevalence may be influenced by theprice and availability of tobacco, as well as awareness of the risks ofsmoking, and notes that a proposed directive to harmonise tobaccotaxation within the EC would reduce the level of taxation in the UKand probably raise the level of consumption.The report also includes worked examples on four other priority

areas already studied-alcohol-related harm, birth control,surveillance and control of infectious disease (childhoodimmunisation, sexually transmitted diseases, foodbome illness),and disability in the elderly. There is a need, says the report, forlarge-scale longitudinal studies of alcohol consumption and forinformation on waiting times for hospital-based family-planningservices. A reduction in the number of beds for stroke patients (15per 10 000 population, compared with 17.4 at present) could beachieved, says the report, by developing community facilities (suchas physiotherapy) and by the simple preventive measure of askinggeneral practitioners to monitor patients’ blood pressure.A second report, to be published next year, will present more

detailed evidence of the effectiveness of specific interventions.

1. UK levels of health. Faculty of Public Health Medicine, 4 St Andrew’s Place, LondonNW1 4LB. £5.90.

Junior doctors’ hours

An agreement between the Government, the medical RoyalColleges, and the British Medical Association, announced last week,aims to cut the number of hours worked by junior doctors andimprove their living and working conditions. Introducing thechanges, the Secretary of State for Health, William Waldegrave,said that the maximum number of hours worked would be reduced"as soon as practicable" to 83 per week on average. By the end of1994 junior doctors in the busiest jobs would be working amaximum of 72 hours per week. Some higher specialist trainees willbe allowed to work more than 72 hours if it would benefit their

training and if they wish to do so.The Government is making available 12-4 million to fund 200

new consultant and 50 staff-grade posts in England to achieve thesereductions. Between 429 000 and ;[441000 was allocated to eachregional health board last month to enable them to start making thenecessary appointments.The agreement will limit maximum periods of continuous duty

and minimum time off, bringing to an end the 80-hour weekend.Junior doctors’ salaries will be protected when they changecontracts, despite a reduction in hours worked. A basic rate of paywill apply to the first 40 hours worked (in a full-time training post),with appropriate extra payment for additional hours.The new agreement will introduce more flexible working

patterns, based on full shifts (in which the junior doctor will workcontinuously for no more than 10, or at weekends 13, hours) andpartial shifts (less intensive work, maximum 13-16 hours). Theproposed arrangements also provide for greater use of cross-overcover between junior doctors in different disciplines.Recommendations for team-based methods of working are directedat consultants, who will lead the teams. However, the CentralConsultants and Specialists Committee of the BMA points out thatthe problem of excessive hours should not be transferred fromtrainees to consultants.Mr Waldegrave called on health authorities to tackle the poor

living and working conditions of many junior doctors. Guidanceissued by the National Health Service Management Executivestates that on-call rooms "should not be regarded as second-classaccommodation". The Royal Colleges and universities can

withdraw educational approval from posts where accommodationdoes not meet acceptable standards.

Health authorities have received guidance on the roles andresponsibilities of the regional task forces set up to implement thereduction in working hours. The task forces are expected to report,by the end of 1993, on the implications of reducing hours in all poststo 72 hours a week by the end of 1996.

Diabetic mice (and men)Gene mapping has revealed extensive homology between the

human and mouse genomes-all genes so far mapped on humanchromosome 17, for instance, have homologues on mouse

chromosome 11. So the identification of two murine genes thatinfluence the onset of autoimmune type I diabetes mellitus,reported in Nature last week/ has given rise to well-foundedspeculation that homologous genes will be found in man-one onchromosome 17, the other possibly on chromosome 1 or 4.

Susceptibility to type I diabetes clearly has a large environmentalcomponent, since identical twins of affected subjects have only a36% chance of manifesting the disease. The disorder also appears tobe polygenic, for predisposition is already known to be associatedwith three major histocompatibility complex (MHC) class II genes,HLA-DQAJ, DQBJ, and DRBJ, on chromosome 6. The insulingene region on chromosome 11 is also associated with susceptibilityto the disease. How many genes affect diabetes susceptibility andhow many different combinations of genes produce the sameclinical phenotype has not been reliably estimated.A murine diabetes susceptibility gene, Idd-1, has already been

located in the MHC region on chromosome 17 of non-obesediabetic (NOD) mice, but Idd-3 and Idd-4, the genes identified byTodd et al,l lie on chromosomes 3 and 11, respectively, suggestingthat susceptibility to murine type I diabetes is under the control of atleast three unlinked loci. A further mouse gene, Idd-2 onchromosome 9, also appears to influence susceptibility to diabetes inback-crosses between NOD mice and NOD x NON (diabetesresistant) hybrids. The observations of Todd’s group also give someindication of the complexity of the genetic control of diabetes: Idd-3 3but not Idd4 is associated with insulitis, and Idd-4 but not Idd-3 isseen only in association with diabetes of very early onset.

1. Todd JA, Aitman TJ, Cornall RJ, et al. Genetic analysis of autoimmune type Idiabetes mellitus in mice. Nature 1991; 351: 542-47.

Abnormal genes, prevalent diseases

In sponsoring a conference on the Molecular Genetics ofCommon Diseases the newly formed Caledonian ResearchFoundation and the more venerable Royal Society of Edinburghseemed to be recognising a dilemma, a frustration even.

Haemoglobinopathies apart, the clinical applications of moleculargenetics have tended to be in rare diseases. The foci in Edinburghon June 13 and 14 included cancer, hypertension, heart disease, anddiabetes.What cancer research groups are beginning to achieve is a

recognition of the molecular steps (hits) that parallel the classicalpathologist’s view of the road from normal cell to malignant state. Inthese sequences p53 proved to be a frequent participant: inPrinceton shortly this tumour suppressor protein will be whollyunavoidable, since a whole workshop is to be devoted to it. E. R.Fearon (Baltimore) discussed six gene changes in colorectal cancer;in any one tumour just three or four might be found, but in somenone at all. The changes included 17p losses, right in the "hot spot"region of p53 mutations, late in the sequence; 18q losses in 75% oftumours, perhaps earlier than 17p; and the 5q abnormalities nowrecognised in familial adenomatosis coli. D. Lane (Dundee) foundthat 75 % of a mixed bag of malignant tissues stained with anti-p53.The frequency was especially high in melanoma and in gastriccancer, where p53 proved to carry a prognostic message. Thesession on genetic predisposition to common cancers naturallyfocused on "cancer families". These tragic pedigrees are rare, andthe light they throw on the individually common cancers that makeup the Li-Fraumeni syndrome, for example, is dim so far. Facedwith a 4-year-old child with a p53 mutation who is from one suchfamily but is cancer-free, what do you do, asked F. P. Li (Boston).In his group there was a moratorium on testing presymptomaticallyuntil the many issues had been resolved. The colon, when involvedin risk families, is at least accessible; but what about non-colonicsites (desmoid tumours, biliary tumours), asked C. M. Steel

(Edinburgh). Families did like to know, he claimed: their doctorsmight previously have dismissed the very idea of the cancer-prone