1448
cell volume,
by uraemia, and by many drugs, especially aspirin; it may also be influenced by hypertension and by a raised serum bilirubin. Rodgers and Levin2have now re-examined more than 1000 published studies of the bleeding time. The conclusion from their thorough mathematical scrutiny is clear; there is very little scientific evidence to support the use of the bleeding time as a diagnostic test or as a predictor of clinically significant bleeding in individual patients. They review the much cited work of Harker and Slichter3concerning the relation between bleeding time and platelet count and question its general applicability. Although they concede that standardisation of the method would be in everyone’s interest, they could find no evidence that newer versions produce any improvement in the low sensitivity and specificity of the test. In the assessment of patients who may have a bleeding disorder, by far the most important thing is an accurate and complete history, including a drug history and details of the family. If the history is not informative and platelet count and coagulation tests are normal, a skin bleeding time is probably superfluous. Perhaps clinicians are reassured by watching haemostasis in action; if the wound stops bleeding before one’s eyes and one can see the strands of fibrin drawn out by the filter paper then it is tempting to believe that there should be no bleeding after, say, a renal biopsy. The evidence is very clear that this conclusion could be seriously wrong. Used judiciously,4 the bleeding time deserves to remain as part of the assessment of individual patients with histories suggestive of bleeding disorders. The test requires very little equipment and no laboratory facilities and therefore has a place in epidemiological field work. Careful prospective trials are still needed to determine whether the bleeding time can be a useful predictor of clinically significant bleeding; the variables affecting the test are known and welldesigned studies should give a clear answer. 1. Milian MG. Technique pour l’étude de la coagulation du sang. Bull Mem Soc Med Hop Paris 1901; 18: 777-83 (cited in ref 2). 2. Rodgers RPC, Levin J. A critical review of the bleeding time. Semin Thromb Hemost 1990; 16: 1-20. 3. Harker LA, Slichter SJ. The bleeding time as a screening test for evaluation of platelet function. N Engl J Med 1972; 287: 155-59. 4. Hamblin TJ. What about the bleeding time? Br Med J 1985; 291: 91.
Pulling British undergraduate medical education into the twentieth century At the May meeting of the General Medical Council (GMC), the education committee presented new directions for undergraduate medical education. Recognising that the 1980 Recommendations on Basic Medical Education1 have had very little impact, the GMC has approved a new set of proposals for consultation with the licensing bodies. The main thrusts are towards more integrated (and thus relevant, effective, and interesting) teaching, with
various threads specified throughout the five years of medical school, and towards a core-plus-options approach, to get away from the straitjacket2 of contemporary medical education. Although a few British medical schools have tried to develop curricula based on twentieth century needs and pedagogy, undergraduate medical education in the UK is still driven largely by tradition. The new proposals will ensure that the big departments in both basic science and clinical disciplines play a part determined less by traditional clout and more by educational need. The implications for some medical schools are greater than for others. They are perhaps greatest for the preclinical faculties in some of the older universities, who keep themselves very separate from the world of patients and "real" medicine. There are far more overwhelming implications for the GMC itself. Responsibility for implementing its education function—covering all stages of medical education (undergraduate, postgraduate, continuing) -is devolved to six administrators. Education took up 259 372 (49%) of the GMC’s annual expenditure for the year ending December, 1989. By comparison, the Association of American Medical Colleges (the nearest comparable body as regards education in the USA), which is funded mainly by dues from the medical schools and teaching hospitals, spent over$6 million in 1989/90 on educational matters and accreditation.3So the GMC must obtain the necessary skills and manpower to pursue this initiative, if necessary seeking to review its funding structure. Ordinary registered medical practitioners, whose annual fees are a major source of income for the GMC, may well ask why they have, in effect, to fund the reform of the medical schools. Educationists will be quick to realise an inevitable implication of the variety of medical education produced by a system of core courses and optionsthe need for a national assessment procedure. Such an arrangement will be required to monitor schools’ standards overall and also to guarantee individuals’ core knowledge and skills in the public interest. A national examination could be conducted either as an entry requirement to the final MB or as an additional prerequisite to registration. In the absence of a credible organisation that could represent all medical schools for this purpose, the GMC would need to take on an additional role. Contemporary final medical examinations, occasionally inspected for the GMC by a group of senior academics, have been criticised for being uninspired, inappropriate,4 and even incompetent. Thus most schools continue to use "long cases" as key components of finals,s despite overwhelming evidence that clinical skills of candidates vary considerably between cases.6Reliance on a single long case is thus unjust and unwise. A central examination body could help to devise the type of innovative certification procedures that are being developed in Canada,for
example.
1449
The GMC’s plans deserve broad support from medical schools and the public as a whole. There will have to be discussion about matters of detail--eg, some may feel that the proposed balance between core and options (2:1) makes for a restrictively fat core. Above all, the GMC will need to acquire professional and administrative functions to cope with development and implementation of the proposals, and acknowledge the consequent requirement for a national assessment facility.
1. General Medical Council Education Committee. Recommendations on Basic Medical Education. London: General Medical Council, 1980. 2. Pickering G. Quest for excellence in medical education. Oxford: Oxford University Press (for the Nuffield Provincial Hospitals Trust), 1978: 82. 3. Association of American Medical Colleges. Annual report 1989-90. Washington DC: Association of American Medical Colleges, 1990: 34. 4. Pickering G. Quest for excellence in medical education. Oxford: Oxford University Press (for the Nuffield Provincial Hospitals Trust), 1978: 64-70. 5. General Medical Council Education Committee. Basic Medical Education in the British Isles. London: Nuffield Provincial Hospitals Trust, 1977: 111. 6. van der Vleuten CPM, Swanson DB. Assessment of clinical skills with standardised patients: state of the art. Teach Learn Med 1990; 2: 58-76. 7. Page G, Bordage G, Harasym P, Bowmer I, Swanson DB. A revision of the Medical Council of Canada’s qualifying examination: pilot test results. In: Bender W, Heimstra RJ, Scherpbier AJJA, Zwierstra RP, eds. Teaching and assessing clinical competence: proceedings of the Third International Conference on Teaching and Assessing Clinical Competence, Groningen, the Netherlands, 1989. Boekwerk, 1980: 403-07.
Diagnosis of early onchocerciasis The filarial worm Onchocerca volvulus infects about 18 million people in Africa and Latin America.1 It causes severe itching, disfiguring skin lesions, and various ocular lesions which may result in blindness (river blindness). Since 1976, the Onchocerciasis Control Programme of the World Health Organisation has been outstandingly successful in interrupting transmission via control of the black fly vector, Simulium, and mass treatment of patients with ivermectin.12 Consequently, in over a million square km, children born since the onset of vector control live free from infection. Diagnosis of early onchocerciasis is difficult. 0 volvulus microfilariae may be hard to find in skin snips in light or early infections. The condition can also be diagnosed by slit lamp examination of the eye, or by finding adult worms in resected subcutaneous nodules, but eye damage and nodules are features of heavy infections. 0 volvulus does not infect convenient laboratory hosts, and serological diagnosis has been hindered by the poor sensitivity and specificity of assays that are based on other filarial species.1,3,4 Moreover, 7-24 months usually elapse between infection and the production of detectable microfilariae by fertilised adult female worms-the prepatent period. The characteristic itchy rash may not begin until 1-3 years after infection.
For all these reasons there is
an
urgent need for an
immunodiagnostic test specific for 0 volvulus that can detect early and prepatent infections. Such a test could reveal whether new infections are occurring in an area previously under vector control. In this respect, the report by Lobos and colleagues4 is very promising. These researchers have cloned and expressed in an Escherichia coli plasmid a complementary DNA fragment encoding for a low molecular weight 0 volvulus antigen, OV-16.3,4 This antigen seems to be an excretory or secretory product of the adult female worm, and to be an immunodominant antigen. Antigenicity of OV-16 was conserved among 0 volvulus isolates from different areas of West Africa and from Guatemala. When OV-16 was used as the antigen in an enzyme-linked immunosorbent assay, 0 volvulus-specific antibodies were detected in 37 of 41 patients with onchocerciasis. There was only 1 false-positive among 57 patients with other filarial infections. More important, in 3 of 7 children from Mali, OV-16 antibodies were present a year or more before microfilariae were first found, and in 2 chimpanzees infected in the laboratory, OV-16 antibodies appeared 3-12 months before microfilariae could be detected. There was no correlation between OV-16 antibodies and the microfilarial density in the skin. The next step will be to adapt serodiagnosis based on OV-16 to field conditions, by use of drops of blood collected on filter paper, or of urine or saliva specimens. If such adaptation can be achieved, it could prove very important in monitoring any reinvasion of infective black flies and the safety of the Onchocerciasis Control Programme.
Expert Committee on Onchocerciasis. Third report. WHO Tech Rep Ser 1987; 752. Taylor HR, Pacque M, Munoz B, Greene BM. Impact of mass treatment
1. WHO 2.
of onchocerciasis with ivermectin on the transmission of infection. Science 1990; 250: 116-18. 3. Lobos E, Altman M, Mengod G, Weiss N, Rudin W, Karam M. Identification of an Onchocerca volvulus cDNA encoding a lowmolecular-weight antigen uniquely recognised by onchocerciasis patient sera. Mol Biochem Parasitol 1990; 39: 135-46. 4. Lobos E, Weiss N, Karam M, Taylor HR, Ottesen EA, Nutman TB. An immunogenic Onchocerca volvulus antigen: a specific and early marker of infection. Science 1991; 251: 1603-05.
Ultrafast CT for coronary calcification
Coronary disease exacts its most devastating effects in early-middle-aged men. Consequently, medical examinations of the symptom-free population are widely used by industry and by health insurance organisations with special reference to risk factors such as family history, obesity, hypertension, smoking, exercise habits, and measurement of serum lipids. On the basis of the findings, advice is given as to how to reduce the possibility of symptomatic coronary disease by appropriate therapy and changes in life
cell volume,
by uraemia, and by many drugs, especially aspirin; it may also be influenced by hypertension and by a raised serum bilirubin. Rodgers and Levin2have now re-examined more than 1000 published studies of the bleeding time. The conclusion from their thorough mathematical scrutiny is clear; there is very little scientific evidence to support the use of the bleeding time as a diagnostic test or as a predictor of clinically significant bleeding in individual patients. They review the much cited work of Harker and Slichter3concerning the relation between bleeding time and platelet count and question its general applicability. Although they concede that standardisation of the method would be in everyone’s interest, they could find no evidence that newer versions produce any improvement in the low sensitivity and specificity of the test. In the assessment of patients who may have a bleeding disorder, by far the most important thing is an accurate and complete history, including a drug history and details of the family. If the history is not informative and platelet count and coagulation tests are normal, a skin bleeding time is probably superfluous. Perhaps clinicians are reassured by watching haemostasis in action; if the wound stops bleeding before one’s eyes and one can see the strands of fibrin drawn out by the filter paper then it is tempting to believe that there should be no bleeding after, say, a renal biopsy. The evidence is very clear that this conclusion could be seriously wrong. Used judiciously,4 the bleeding time deserves to remain as part of the assessment of individual patients with histories suggestive of bleeding disorders. The test requires very little equipment and no laboratory facilities and therefore has a place in epidemiological field work. Careful prospective trials are still needed to determine whether the bleeding time can be a useful predictor of clinically significant bleeding; the variables affecting the test are known and welldesigned studies should give a clear answer. 1. Milian MG. Technique pour l’étude de la coagulation du sang. Bull Mem Soc Med Hop Paris 1901; 18: 777-83 (cited in ref 2). 2. Rodgers RPC, Levin J. A critical review of the bleeding time. Semin Thromb Hemost 1990; 16: 1-20. 3. Harker LA, Slichter SJ. The bleeding time as a screening test for evaluation of platelet function. N Engl J Med 1972; 287: 155-59. 4. Hamblin TJ. What about the bleeding time? Br Med J 1985; 291: 91.
Pulling British undergraduate medical education into the twentieth century At the May meeting of the General Medical Council (GMC), the education committee presented new directions for undergraduate medical education. Recognising that the 1980 Recommendations on Basic Medical Education1 have had very little impact, the GMC has approved a new set of proposals for consultation with the licensing bodies. The main thrusts are towards more integrated (and thus relevant, effective, and interesting) teaching, with
various threads specified throughout the five years of medical school, and towards a core-plus-options approach, to get away from the straitjacket2 of contemporary medical education. Although a few British medical schools have tried to develop curricula based on twentieth century needs and pedagogy, undergraduate medical education in the UK is still driven largely by tradition. The new proposals will ensure that the big departments in both basic science and clinical disciplines play a part determined less by traditional clout and more by educational need. The implications for some medical schools are greater than for others. They are perhaps greatest for the preclinical faculties in some of the older universities, who keep themselves very separate from the world of patients and "real" medicine. There are far more overwhelming implications for the GMC itself. Responsibility for implementing its education function—covering all stages of medical education (undergraduate, postgraduate, continuing) -is devolved to six administrators. Education took up 259 372 (49%) of the GMC’s annual expenditure for the year ending December, 1989. By comparison, the Association of American Medical Colleges (the nearest comparable body as regards education in the USA), which is funded mainly by dues from the medical schools and teaching hospitals, spent over$6 million in 1989/90 on educational matters and accreditation.3So the GMC must obtain the necessary skills and manpower to pursue this initiative, if necessary seeking to review its funding structure. Ordinary registered medical practitioners, whose annual fees are a major source of income for the GMC, may well ask why they have, in effect, to fund the reform of the medical schools. Educationists will be quick to realise an inevitable implication of the variety of medical education produced by a system of core courses and optionsthe need for a national assessment procedure. Such an arrangement will be required to monitor schools’ standards overall and also to guarantee individuals’ core knowledge and skills in the public interest. A national examination could be conducted either as an entry requirement to the final MB or as an additional prerequisite to registration. In the absence of a credible organisation that could represent all medical schools for this purpose, the GMC would need to take on an additional role. Contemporary final medical examinations, occasionally inspected for the GMC by a group of senior academics, have been criticised for being uninspired, inappropriate,4 and even incompetent. Thus most schools continue to use "long cases" as key components of finals,s despite overwhelming evidence that clinical skills of candidates vary considerably between cases.6Reliance on a single long case is thus unjust and unwise. A central examination body could help to devise the type of innovative certification procedures that are being developed in Canada,for
example.
1449
The GMC’s plans deserve broad support from medical schools and the public as a whole. There will have to be discussion about matters of detail--eg, some may feel that the proposed balance between core and options (2:1) makes for a restrictively fat core. Above all, the GMC will need to acquire professional and administrative functions to cope with development and implementation of the proposals, and acknowledge the consequent requirement for a national assessment facility.
1. General Medical Council Education Committee. Recommendations on Basic Medical Education. London: General Medical Council, 1980. 2. Pickering G. Quest for excellence in medical education. Oxford: Oxford University Press (for the Nuffield Provincial Hospitals Trust), 1978: 82. 3. Association of American Medical Colleges. Annual report 1989-90. Washington DC: Association of American Medical Colleges, 1990: 34. 4. Pickering G. Quest for excellence in medical education. Oxford: Oxford University Press (for the Nuffield Provincial Hospitals Trust), 1978: 64-70. 5. General Medical Council Education Committee. Basic Medical Education in the British Isles. London: Nuffield Provincial Hospitals Trust, 1977: 111. 6. van der Vleuten CPM, Swanson DB. Assessment of clinical skills with standardised patients: state of the art. Teach Learn Med 1990; 2: 58-76. 7. Page G, Bordage G, Harasym P, Bowmer I, Swanson DB. A revision of the Medical Council of Canada’s qualifying examination: pilot test results. In: Bender W, Heimstra RJ, Scherpbier AJJA, Zwierstra RP, eds. Teaching and assessing clinical competence: proceedings of the Third International Conference on Teaching and Assessing Clinical Competence, Groningen, the Netherlands, 1989. Boekwerk, 1980: 403-07.
Diagnosis of early onchocerciasis The filarial worm Onchocerca volvulus infects about 18 million people in Africa and Latin America.1 It causes severe itching, disfiguring skin lesions, and various ocular lesions which may result in blindness (river blindness). Since 1976, the Onchocerciasis Control Programme of the World Health Organisation has been outstandingly successful in interrupting transmission via control of the black fly vector, Simulium, and mass treatment of patients with ivermectin.12 Consequently, in over a million square km, children born since the onset of vector control live free from infection. Diagnosis of early onchocerciasis is difficult. 0 volvulus microfilariae may be hard to find in skin snips in light or early infections. The condition can also be diagnosed by slit lamp examination of the eye, or by finding adult worms in resected subcutaneous nodules, but eye damage and nodules are features of heavy infections. 0 volvulus does not infect convenient laboratory hosts, and serological diagnosis has been hindered by the poor sensitivity and specificity of assays that are based on other filarial species.1,3,4 Moreover, 7-24 months usually elapse between infection and the production of detectable microfilariae by fertilised adult female worms-the prepatent period. The characteristic itchy rash may not begin until 1-3 years after infection.
For all these reasons there is
an
urgent need for an
immunodiagnostic test specific for 0 volvulus that can detect early and prepatent infections. Such a test could reveal whether new infections are occurring in an area previously under vector control. In this respect, the report by Lobos and colleagues4 is very promising. These researchers have cloned and expressed in an Escherichia coli plasmid a complementary DNA fragment encoding for a low molecular weight 0 volvulus antigen, OV-16.3,4 This antigen seems to be an excretory or secretory product of the adult female worm, and to be an immunodominant antigen. Antigenicity of OV-16 was conserved among 0 volvulus isolates from different areas of West Africa and from Guatemala. When OV-16 was used as the antigen in an enzyme-linked immunosorbent assay, 0 volvulus-specific antibodies were detected in 37 of 41 patients with onchocerciasis. There was only 1 false-positive among 57 patients with other filarial infections. More important, in 3 of 7 children from Mali, OV-16 antibodies were present a year or more before microfilariae were first found, and in 2 chimpanzees infected in the laboratory, OV-16 antibodies appeared 3-12 months before microfilariae could be detected. There was no correlation between OV-16 antibodies and the microfilarial density in the skin. The next step will be to adapt serodiagnosis based on OV-16 to field conditions, by use of drops of blood collected on filter paper, or of urine or saliva specimens. If such adaptation can be achieved, it could prove very important in monitoring any reinvasion of infective black flies and the safety of the Onchocerciasis Control Programme.
Expert Committee on Onchocerciasis. Third report. WHO Tech Rep Ser 1987; 752. Taylor HR, Pacque M, Munoz B, Greene BM. Impact of mass treatment
1. WHO 2.
of onchocerciasis with ivermectin on the transmission of infection. Science 1990; 250: 116-18. 3. Lobos E, Altman M, Mengod G, Weiss N, Rudin W, Karam M. Identification of an Onchocerca volvulus cDNA encoding a lowmolecular-weight antigen uniquely recognised by onchocerciasis patient sera. Mol Biochem Parasitol 1990; 39: 135-46. 4. Lobos E, Weiss N, Karam M, Taylor HR, Ottesen EA, Nutman TB. An immunogenic Onchocerca volvulus antigen: a specific and early marker of infection. Science 1991; 251: 1603-05.
Ultrafast CT for coronary calcification
Coronary disease exacts its most devastating effects in early-middle-aged men. Consequently, medical examinations of the symptom-free population are widely used by industry and by health insurance organisations with special reference to risk factors such as family history, obesity, hypertension, smoking, exercise habits, and measurement of serum lipids. On the basis of the findings, advice is given as to how to reduce the possibility of symptomatic coronary disease by appropriate therapy and changes in life
