- Email: [email protected]
MORE EFFECTS OF CIGARETTES
1013
of calcium has been largely but there are indications that the difference in intake due to the water contribution may be sizeable 18 19; if absorption factors are taken into account it may be even more important. Ideas concerning calcium homoeostasis are changing 20: it is no longer thought to depend on bone as a depot but to be much more a matter of absorption and excretion, with the kidneys playing a major role.21 Water calcium, being mainly in ionised form, may be of special importance. There are many questions here which need ad-hoc investigation. Clearly, the elucidation of the whole " water story " is important because of the large number of deaths concerned and because clues may be found to the pathogenesis of some aspects of cardiovascular disease in general.
Drinking-water as a ignored in the past
source
18. Widdowson, E. M. Br. med. Bull. 1944, 10, 219. 19. Report of the Government Chemist. H.M. Stationery Office, 1963. 20. see Lancet, 1968, ii, 1379. 21. Peacock, M., Robertson, W. G., Nordin, B. E. C. Lancet, Feb. 22, 1969,
p. 384.
Annotations MORE EFFECTS OF CIGARETTES
publicised dangers of smoking are bronchial chronic bronchitis and cardiovascular disease. carcinoma, There are many other possibilities, however, which are receiving increasing attention. The habituating effects of nicotineare associated with its actions on the central nervous system; and, though much is known about these effects in animals, comparatively little is known about the central action of nicotine in man. Evidence has come to light, however, which indicates that these effects are strong and could be important. Webster2 reported that cigarette smoking caused a dramatic but transient reduction in skeletal muscle tone in spastic patients. Domino and von Baumgarten3 have now examined the effects on the patella reflex of 115 young men of smoking cigarettes of differing nicotine content. The reflex was elicited automatically by a reflex hammer attached to a solenoid and recorded by a strain-gauge transducer and electromyogram of the ipsilateral quadriceps femoris muscle. Negligible depression of the reflex was produced by smoking a nicotine-free lettuce cigarette. A low-nicotine tobacco cigarette produced approximately 45% depression within five minutes and a high-nicotine cigarette 67% depression. A second cigarette smoked 25 minutes after the first produced a similar depression. No significant differences were found between smokers and non-smokers. No conclusions could be drawn concerning the site of action of nicotine in producing patella-reflex depression, but these observations are of importance from many aspects; for example, patella responses during clinical examinations may be influenced by a recently smoked cigarette. The implications as far as motor function in general is concerned must also be considered. Welch et al. describe placentas obtained after childbirth from 17 non-smoking and 17 smoking women. They measured the activity of enzymes which hydroxyTHE best
late
3, 4 benzpyrene and N-demethylate 3-methyl-4-
monomethylamino-azobenzene. No activity was detected in the placentas from non-smoking women, but these enzymes were detected in varying concentrations in placentas from smokers. Welch et al. conclude that the induction of these enzymes is probably caused by systemic absorption of polycyclic hydrocarbons in cigarette smoke and by their transport to the placenta. Once again, the implications of this work are many and important. The effects of cigarette smoking on enzyme induction not only in the placenta but also in other organs will require further study. We must also inquire whether carcinogenic polycyclic hydrocarbons can pass from the placenta into the human fetus, and, if so, what action they may have.
OVERSEAS MEDICAL STUDENTS IN BRITAIN
STATISTICIANS of higher education have lately adopted definition for "overseas student". As a result about 1 student in every 10 under the old system no longer counts as overseas. The latest (new definition) figures issued by the Association of Commonwealth Universities1 show that at the beginning of the academic year 1967-68, 16,045 men and women from overseas were enrolled for full-time study or research in British universities. 1727 were studying medicine, dentistry, or other subjects directly related to health. 1085 were studying medicine, 740 at the postgraduate level. Of 525 part-time students in the medicine, dentistry, and health category, all but 26 were doing postgraduate work. a new
AN ABC OF MEDICAL GENETICS
About 2% of all liveborn children carry a chromosome abnormality or mutant gene which significantly affects their health. As more and more diseases caused by infection and other environmental influences are being brought under control, so are genetically determined disorders becoming relatively more prominent. The apparent paradox of the maintenance of both human diversity and family likeness in successive generations has intrigued men for centuries; for the medical practitioner, however, human heredity is no longer a matter for idle speculation. On p. 1014 this week, Dr. C. 0. Carter begins a series of seven articles in which he will examine the mechanical, chemical, and arithmetical
bases of inheritance in man, the way in which successful treatment of some inherited conditions is changing the frequency of mutant genes in the population, and the objectives of genetic counselling and the assessment of risk. The seven articles, together with some additional material, will be published as a book later this year.
HARDLY AN EXPERIMENT
Having reached this
page,
inquiring readers
may
begin
to wonder whether The Lancet is conducting a small experiment with new type faces. That is not so. These words were set in type in Worcester, Massachusetts, where we will continue to produce the journal (though, inevitably, it
will be smaller than usual) until normal work sumed at our printers in Watford, England.
can
be
re-
1. See
Lancet, 1968, i, 579. Webster, D. D. Clin. Pharmac. Ther. 1964, 5, 900. 3. Domino, E. F., von Baumgarten, A. M. ibid. 1969, 10, 72. 4. Welch, R. M. et al. ibid. p. 100. 2.
1. Students from Other Countries in Universities in Britain
Obtainable from the Association of 36 Gordon Square, London W.C.1.
Commonwealth
1967-68.
Universities,
of calcium has been largely but there are indications that the difference in intake due to the water contribution may be sizeable 18 19; if absorption factors are taken into account it may be even more important. Ideas concerning calcium homoeostasis are changing 20: it is no longer thought to depend on bone as a depot but to be much more a matter of absorption and excretion, with the kidneys playing a major role.21 Water calcium, being mainly in ionised form, may be of special importance. There are many questions here which need ad-hoc investigation. Clearly, the elucidation of the whole " water story " is important because of the large number of deaths concerned and because clues may be found to the pathogenesis of some aspects of cardiovascular disease in general.
Drinking-water as a ignored in the past
source
18. Widdowson, E. M. Br. med. Bull. 1944, 10, 219. 19. Report of the Government Chemist. H.M. Stationery Office, 1963. 20. see Lancet, 1968, ii, 1379. 21. Peacock, M., Robertson, W. G., Nordin, B. E. C. Lancet, Feb. 22, 1969,
p. 384.
Annotations MORE EFFECTS OF CIGARETTES
publicised dangers of smoking are bronchial chronic bronchitis and cardiovascular disease. carcinoma, There are many other possibilities, however, which are receiving increasing attention. The habituating effects of nicotineare associated with its actions on the central nervous system; and, though much is known about these effects in animals, comparatively little is known about the central action of nicotine in man. Evidence has come to light, however, which indicates that these effects are strong and could be important. Webster2 reported that cigarette smoking caused a dramatic but transient reduction in skeletal muscle tone in spastic patients. Domino and von Baumgarten3 have now examined the effects on the patella reflex of 115 young men of smoking cigarettes of differing nicotine content. The reflex was elicited automatically by a reflex hammer attached to a solenoid and recorded by a strain-gauge transducer and electromyogram of the ipsilateral quadriceps femoris muscle. Negligible depression of the reflex was produced by smoking a nicotine-free lettuce cigarette. A low-nicotine tobacco cigarette produced approximately 45% depression within five minutes and a high-nicotine cigarette 67% depression. A second cigarette smoked 25 minutes after the first produced a similar depression. No significant differences were found between smokers and non-smokers. No conclusions could be drawn concerning the site of action of nicotine in producing patella-reflex depression, but these observations are of importance from many aspects; for example, patella responses during clinical examinations may be influenced by a recently smoked cigarette. The implications as far as motor function in general is concerned must also be considered. Welch et al. describe placentas obtained after childbirth from 17 non-smoking and 17 smoking women. They measured the activity of enzymes which hydroxyTHE best
late
3, 4 benzpyrene and N-demethylate 3-methyl-4-
monomethylamino-azobenzene. No activity was detected in the placentas from non-smoking women, but these enzymes were detected in varying concentrations in placentas from smokers. Welch et al. conclude that the induction of these enzymes is probably caused by systemic absorption of polycyclic hydrocarbons in cigarette smoke and by their transport to the placenta. Once again, the implications of this work are many and important. The effects of cigarette smoking on enzyme induction not only in the placenta but also in other organs will require further study. We must also inquire whether carcinogenic polycyclic hydrocarbons can pass from the placenta into the human fetus, and, if so, what action they may have.
OVERSEAS MEDICAL STUDENTS IN BRITAIN
STATISTICIANS of higher education have lately adopted definition for "overseas student". As a result about 1 student in every 10 under the old system no longer counts as overseas. The latest (new definition) figures issued by the Association of Commonwealth Universities1 show that at the beginning of the academic year 1967-68, 16,045 men and women from overseas were enrolled for full-time study or research in British universities. 1727 were studying medicine, dentistry, or other subjects directly related to health. 1085 were studying medicine, 740 at the postgraduate level. Of 525 part-time students in the medicine, dentistry, and health category, all but 26 were doing postgraduate work. a new
AN ABC OF MEDICAL GENETICS
About 2% of all liveborn children carry a chromosome abnormality or mutant gene which significantly affects their health. As more and more diseases caused by infection and other environmental influences are being brought under control, so are genetically determined disorders becoming relatively more prominent. The apparent paradox of the maintenance of both human diversity and family likeness in successive generations has intrigued men for centuries; for the medical practitioner, however, human heredity is no longer a matter for idle speculation. On p. 1014 this week, Dr. C. 0. Carter begins a series of seven articles in which he will examine the mechanical, chemical, and arithmetical
bases of inheritance in man, the way in which successful treatment of some inherited conditions is changing the frequency of mutant genes in the population, and the objectives of genetic counselling and the assessment of risk. The seven articles, together with some additional material, will be published as a book later this year.
HARDLY AN EXPERIMENT
Having reached this
page,
inquiring readers
may
begin
to wonder whether The Lancet is conducting a small experiment with new type faces. That is not so. These words were set in type in Worcester, Massachusetts, where we will continue to produce the journal (though, inevitably, it
will be smaller than usual) until normal work sumed at our printers in Watford, England.
can
be
re-
1. See
Lancet, 1968, i, 579. Webster, D. D. Clin. Pharmac. Ther. 1964, 5, 900. 3. Domino, E. F., von Baumgarten, A. M. ibid. 1969, 10, 72. 4. Welch, R. M. et al. ibid. p. 100. 2.
1. Students from Other Countries in Universities in Britain
Obtainable from the Association of 36 Gordon Square, London W.C.1.
Commonwealth
1967-68.
Universities,