1299 subunits have been characterised and that 60% of the virus structure is accounted for: the remaining 40%, now under investigation, is thought to ...

339KB Sizes 1 Downloads 68 Views

1299 subunits have been characterised and that 60% of the virus structure is accounted for: the remaining 40%, now under investigation, is thought to be related to T antigen. Work on adenovirus has led to the demonstration of a so-called mini-adenovirus which is detected only in the most oncogenic adenovirus cultures. Such mini-viruses might develop from the large viruses after D.N.A. destruction. They have been shown to retain the property of producing T antigen in transformed cells. The mini-virus cannot produce more virus but it could be capable of producing tumours. Dr. Ian Macpherson discussed the reversion of virustransformed cells to normal in in-vitro cultures. Hamster cells transformed with Rous sarcoma virus might revert spontaneously, possibly because the cells divided faster than the virus, which was thus diluted out. Such a phenomenon suggested that viral genes must be incorporated into a hamster cell before it became malignant. On the other hand, cells transformed by polyoma virus may revert only if tetraploid cells were cloned and chromosome loss induced. Chromosome loss from diploid cells was probably lethal; hence reversion might take place only in tetraploid cells. The findings indicated that polyoma virus, in transforming normal cells, became closely linked with their chromosome structure. Studying the uptake of glucose by polyoma-transformed cells in vitro, Dr. Macpherson had demonstrated that uptake was 5-15 times that of normal cells and was totally independent of insulin. This new finding had caused him to speculate that the rapid growth of malignant cells may be related to their more active and insulin-independent glucose uptake from the host’s circulation. Reviewing the evidence for disregarding the concept of tumour autonomy and accepting that patients could immunologically influence the development and growth of their tumours, Prof. M. F. A. Woodruff described the development of a carcinoma which did not usually metastasise to the kidney in a transplanted kidney from a donor who had an unsuspected primary tumour. This tumour grew in its new host, who was being given chemical immunosuppression, and Professor Woodruff suggested that cancer cells may be spread widely through the body yet give rise to disease only in certain sites. This abnormally sited secondary carcinoma regressed completely after immunosuppression was stopped. Reticulosarcoma had now been reported in 5 patients on immunosuppression after kidney homotransplants. Although there was some evidence that in at least one of those patients the tumour may have been present before immunosuppression, this incidence of reticulosarcoma was very much higher than in the general population. In the light of new ideas about immunological influences in cancer, Professor Woodruff pointed to the need to reassess radical surgery with dissection of regional lymphnodes, radiotherapy, and chemotherapy. It was futile to try to secure immunological control of cancer in patients with large or widespread tumours. Immunotherapy might play a part in the primary treatment of tumours in association with local radical resection. A safe form of treatment, perhaps a non-specific reticuloendothelial agent, increasing host resistance to residual tumour, might prove the most successful approach. Prof. Peter Alexander discussed the successful suppression






methylcholanthrene-induced sarcomas in rats by heterologous sheep lymphocytes and R.N.A. preparations derived from such lymphocytes. Large lymphoblasts had

been detected in efferent lymph from tumour-stimulated regional lymph-nodes: these cells might be the effective cytotoxic cells responsible for tumour destruction. Examining experimental immunotherapy in a range of established tumours of varying antigenicity, Mr. James Boak provided evidence for the view that immunosensitivity in vivo was not related to immunogenicity. Furthermore, inhibition of experimental tumours either on transplantation or after they were established was demonstrable only at threshold dose levels. The discussion on the treatment of clinical cancer by immunotherapy confirmed that the most promising results came when the tumours treated were small, perhaps only approaching threshold dose levels. These findings could support Professor Woodruff’s view that the place of immunotherapy in clinical cancer would lie in a combination of non-specific and safe reticuloendothelial stimulation with surgical resection as the primary treatment. VOCATIONAL TRAINING FOR GENERAL PRACTICE

UTOPIA had its vocational training for general practice well organised years ago: Britain is less advanced. One stage in the evolution of this aspect of medical education is recognisable in Mackenzie’s The Future of Medicine, published in 1919; and another in the 1950 report of a B.M.A. committee on the training of the general practitioner, which set out the idea in detail for the first time. No great strides were made in the 1950s, but the Royal College of General Practitioners, always striving for action on this theme, has ensured that the 1960s will be more fruitful. In 1965 the College’s report1 proposed a

four-year postregistration emerged in the shape

course; and since then much


of reports2 and a little in the of action-such as the formation of a Central Comway mittee on Postgraduate Education, with Sir Robert Aitken as chairman. The College’s latest enterprise, a symposium on June 5 on the implementation of a national plan for vocational training, had at least one doubt to ponder. Would the introduction of three or four years’ compulsory training aggravate the shortage of doctors ? Would it influence more young doctors towards emigration ? Prof. C. M. Fleming believed that recruitment would go up if training became compulsory; and Sir George Godber remarked that in the past very few principals had entered general practice before the age of 30, an average of six years after qualification and plenty of time for a formal training for general practice. The College believesthat to compromise on principles in the interests of expediency would be to store up trouble for the future. The best hope lay in improving the quality of general practice and to delay the necessary measures would only prolong the crisis in general practice. As for the means, Sir George was for more action and less worry about where the money would come from. He also pointed to another change inevitable in any widespread scheme of vocational training. Junior hospital posts which had little to offer the future general practitioner would continue only in the small numbers needed to train consultants. Sir Robert Aitken observed that no ideal solution would be found to the dilemma of a Working Party on Special Vocational Training for General Practice. College of General Practitioners, 1965. 2. See Lancet, 1967, ii, 602. 3. The Implementation of Vocational Training. Royal College of General Practitioners, 1967.


Report of


reconciling two sides of the market-the jobs that would give educational experience and those that would meet the needs of the hospital service. A compromise could never be avoided. A more subtle difficulty was reflected in the surgeons’ complaint that their specialty was much too popular. How were we to head off the overpopulation of surgery ? A system, without direction or posting ", was needed to give gentle guidance in the postregistration years, something between total direction and the present catch-as-catch-can. As for the central body for postgraduate education4 (either as at present constituted or with wider representation, as proposed by the Royal Commission), Sir Robert believed that neither the Colleges nor the Universities would be disposed to accept "

direction from it. information and

Its aims were to collect and circulate use that knowledge to advise the regions on postgraduate education. It would be well placed to give advice to the Ministry of Health and the University Grants Committee; and, admittedly dependent on the General Medical Council’s Recommendations, it would be in close contact with the Council to answer any of its questions. Sir Robert’s hope was that the central body would draw resources from both channels (though not necessarily equally)-from the Ministry and from the Department of Education and Science and the U.G.C. For two years past the Wessex region has organised a course for trainees consisting of a weekly day-release for three 10-week terms.5 Of innovations in prospect, Dr. Andrew Smith told how the postgraduate education committee of Newcastle University had approved a vocational training course drawn up by its generalpractice subcommittee and based on the teaching hospital. All the academic departments would cooperate and the scheme could start this summer if a little money could be got from the Ministry of Health or elsewhere. The course consisted of four phases: three months’ introduction to medical care in general practice; fifteen months of fulltime hospital experience in three-monthly appointments in four subjects, medicine, psychiatry, paediatrics, and obstetrics and gynaecology (the fifth three months to be spent in any one of these); six months’ rotating appointments in special departments; and one year in a teaching general practice. The course would be conducted by a teaching group of five general-practitioner tutors, the senior lecturer in public health, and appropriate members of the family and community medicine teaching group responsible for undergraduate education. How, in fact, was a national plan to be implemented, asked Mr. Gordon McLachlan, who, as secretary of the Nuffield Provincial Hospitals Trust, has done much to promote and foster good ideas about postgraduate education.4 Enthusiasm was not enough. A start must be made soon without national agreement on details. Substantial inducements would be needed to encourage young doctors to undertake vocational training; and this need might be put to the Review Body. As Lord Platt saw it, most of the content of training for general practice was accepted, and there were other wide areas of agreement. The institution of a vocational register might provide the incentive to achieve the status it offered. In the end, however, it all came back to how persuasive was Sir George Godber’s exhortation to get things moving without peering too dejectedly into the coffers. to

4. See Lancet, 1967, ii, 1241. 5. Swift, G. Br. J. med. Educ.

1968, 2, 63.


PEOPLE in most parts of the world have now accepted the need to limit the number of births. In many places, notably India, vasectomy is one of the methods of official choice, and during the past two years some 4 million Indian men have volunteered for the operation. In the United States some 45,000 men are said to seek the operationeach year. In this country sterilisation is seldom used as a method of birth control, and when it is the operation is more often performed on the wife than the husband. Considering the greater ease and safety of the operation in the male this seems illogical. For the 3 past few years, however, the Simon Population Trust has been advocating vasectomy, and if the surgeon’s lingering, and probably unjustifiable, doubts about its legality were formally quashed it might become more common. But some reasons for hesitancy about its use are based on the patient’s attitude and possible psychological sequelse, and these also deserve serious consideration. Many boys have had fears of castration and of impotence, which any suggestion of interference with sexual organs is likely to reactivate. Anxiety and shame may make frank admission of these fears difficult, and sometimes lead to violent opposition to the operation, whether on oneself or on another. (It has even been suggested that a predominantly male judiciary might be unable to look at male sterilisation as objectively as female sterilisation.) Doctors can go some way to meet such fears and fantasies by explaining that vasectomy is not necessarily irreversible-Pheake and Shadke4 reported that 55% of men whose vasa had been rejoined produced childrenand that it does not impair sexual desire or performance. Last year a doctor, after discussing the pros and cons from personal experience, firmly recommended the operation,5and a recent New York study of 73 men, one to five years after vasectomy, is also relevant and encouraging.6 55 of the men were more satisfied with intercourse after the operation than before, and 61 of the wives were reported to be more satisfied. As the wives were not interviewed, this comment is open to some doubt, but frequency of coitus among the group increased at an age when it was decreasing for the general population. 72 men said that they would make the same decision again, and the single dissenter had had two operative failures. But the study showed some reluctance to speak openly on the subject; in some men shame was still present, and infantile fears had clearly been reactivated. Most of the men had coped satisfactorily with these; but where psychological disturbances already exist the prognosis is clearly less good, and such patients should be viewed with considerable caution, especially if their instability is itself a reason for their demanding the operation. In Faber’s study 6 all 73 men had discussed the operation with their wives and 69 wives had agreed. Of these, 3 wives were described as dominant "-i.e., the husband had comwith his wife’s wish. Such a situation must give plied for and a family doctor would do well to ground doubt, seek the help of a psychiatric colleague before a final decision is taken. The study gives no details of the4 wives who disagreed, but to operate in face of a wife’s disapproval seems unwise. "

1. Times, June 4, 1968. 2. Campbell, A. A. Am. J. Obstet. Gynec. 1964, 89, 694. 3. Blacker, C. P., Jackson, L. N. Lancet, 1966, i, 971. 4. Pheake, G. M., Shadke, A. G. J. Urol. 1967, 97, 888. 5. Lancet, 1967, i, 42. 6. Faber, A. S., Tietze, C., Lewit, S. Psychosom. Med.

1967, 29, 354.