296
Abortion LAST week’s reportl from the Select Committee on Abortion hardly rates the muscular response on p. 306-some will say. After
all, the Select Com-
mittee does spotlight some of the uglier aspects of abortion in Britain and, if the committee wants to stem the excess of the private market, who (apart from some private "mercenaries of contemporary capitalism"2) will stand in its way? The main proposals are that, in private practice, the two certifying practitioners should not be partners or have a financial interest in the same nursing home or agency; that referral agencies, pregnancy advisory services, and pregnancy-testing agencies which charge fees should have to be licensed; that the upper limit of gestation at the time of termination should in most cases be 20 weeks (as against 28 now); that women witnesses in legal proceedings concerning abortion should be entitled to anonymity ; that police should be able to apply to a judge for permission to inspect documents in agencies and centres charging fees; and that conscientious objection should be made easier for health workers not wishing to be present at an abortion. Some of these suggestions seem unexceptionable. But, en masse, they take on a destructive air. And, as Professor FAIRWEATHER and his co-signatories say, they do not bear on the role of the National Health Service. If more abortions were done on the N.H.S., we would expect less profiteering in the private market: the committee has nothing to say about unequal provision in different parts of the N.H.S.; and, on the matter of abortion clinics, despite its concern for conscientious objectors, it is silent. The proposals on certification would hamper the activities of the best as well as the worst private agencies. The recommendations, in sum, would make it harder for a woman to have her pregnancy skilfully terminated. Would there then be fewer abortions? Women who desire themselves unpregnant will usually find a way. The only change which would certainly lower the abortion-rate is a drop in the number of unintentional pregnancies. Whatever view one takes of the rights of the fetus, the intervention of policemen and licensing authorities seems less than. apt. "Protection" of women (one stated aim of the anti-abortion movement) is at present best achieved by free access to family-planning advice (something we are working towards), with a fall-back on swift and sympathetic termination under the National Health. In those areas where such help is not regarded as part of ordinary medical care, specially staffed clinics must be the answer. In the organisation of such clinics, the N.H.S. could learn much from the charities. 1. First Report from the Select Committee Stationery Office, 1976. 2. White, J Guardian, July 30.
on
Abortion. H.C. 573 - 1. H.M.
CEREBRAL BLOOD-FLOW
CEREBRAL blood-flow was long believed to be governed almost entirely by humoral mechanisms and negligibly by nerves.’ But fresh scrutinyz3 now discloses that neurogenic mechanisms are important after all-particularly in disease states, such as cerebrovascular accidents. After James’s observationthat the sensitivity of cerebral blood-flow to variations in PC02 was enhanced after stellate ganglionectomy and reduced after cervical vagotomy, other workers recorded vasomotor effects on pial and intracerebral vessels in response both to nerve stimulation and to application of neurotransmitters.5-7 All this was evidence of a definite role for vasomotor nerves in the control of cerebral blood-flow, but interpretations differed. Skinhoj8 took the traditional view that sympathetic cerebrovascular vasomotor nerves were silent under normal conditions, their function being to prevent an undue increase in capillary pressure in conditions of extreme vasodilatation brought about by humoral mechanisms. This argument is supported by the observation that the vasoconstrictor effects of stellateganglion stimulation are pH-dependent,2 5 being absent at a pH above 7.45 ([H+] less than 35 nmol/l) but present below 7.40 ([H+] greater than 40 nmol/1). The other extreme was proposed by Mchedlishvili et al.9—namely, that autoregulation of cerebral blood-flow is mediated primarily by neural rather than humoral mechanisms.9 Harper et al.10 held the middle ground and proposed a dual control system for the cerebral circulation, with predominantly neural control of the larger extraparenchymal vessels and predominantly humoral control of the smaller intraparenchymal vessels,10 the two acting as in-series resistances. This would be in accord with prevailing views on the control of the peripheral circulation in most other peripheral beds. These investigations, and the sharply differing interpretations of the results, have led to a resurgence of interest in the neural control of cerebral blood-flow; but the basic issue-the importance of neural mechanisms in the normal regulation of cerebral perfusion2 3-remains unresolved. The elegant histological and pharmacological investigations of Edvinson and his associatesll reveal that parenchymal as well as pial arteries have an abundant nerve supply and that, associated with the vascular smooth muscle of small cerebral arteries and arterioles, there are not only M andadrenergic and cholinergic receptors, but also H1 and H2 histaminergic and serotoninergic receptors. However, as they stress, it would be foolhardy to conclude that the receptors are necessarily associated with the neurons: receptor sites are needed just as much for local humoral or circulating 1.
Ganong,
W. F. in Review of Medical
Physiology; p. 450.
Los
Altos, Califor-
nia, 1973.
2. Lundgren, O., Jodal, M. A. Rev. Physiol. 1975, 37, 395. 3. Obrist, W. D. Clin. Neurosurg. 1975, 22, 106. 4. James, I. M., Miller, R. A., Purves, M. J. Circulation Res., 1969, 25, 77. 5. Wahl, M. ibid. 1972, 31, 248. 6. D’Alecy, L. G., Feigle, E. O. ibid. 1972, 31, 267. 7. Scremin, O. V., Rovere, A. A., Ragnald, A. C., Giordini, A. Stroke, 1973, 8. 9.
4, 232. Skinhøj, E. ibid. 1972, 3, 711. Mchedlishvili, G. I. Mitagvaria, N. P., Ormatsadye, L G ibid. 1973, 4, 742.
A. M., Deshumkel, V. D., Rowan, J. O., Jennett, W. B. Archs Neurol, 1972, 27, 1. 11. Edvinson, L., Owman, C. m Blood Flow and Metabolism in the Brain (edited by A. M. Harper, W. B. Jennett, J. D. Miller, and J. O. Rowan,
10.
Harper,
p. 1. 18. London, 1975.
297
agents as for transmitters of neural origin. Further, their assumption that the much smaller number of nerve fibres going to the vascular smooth muscle in small parenchymal vessels is merely a reflection of the reduced number of muscle fibres requires confirmation by quantitation of nerve/muscle fibre ratios. In other areas of the peripheral systemic vasculature differences in innervation and intermuscular connections correlate with the predominant method of control.12 Such information is required on the cerebral microcirculation if the conflicting views are to be properly appraised. Much remains to be discovered, but the previous simple model for control of cerebral circulation is clearly adequate no longer. Physical and neural factors operate along with the traditional circulating and local humoral agents. Such a multiple-control system will be far more adaptable than a single control loop. If neural mechanisms are important, we must look again at the use of vasoactive drugs in general and localised cerebrovascular disease. Even though such drugs may increase overall cerebral blood-flow, they could well result in a local cerebral steal,13 with reduced flow to an area with already precarious nutrition.
authorities will have two main problems. Firstly, they will have to analyse enough samples to define the amount of T.C.D.D. released and the extent of the contaminated area. Since T.C.D.D. is very firmly bound to soil and is not translocated in groundwaters, the area of contamination is not necessarily as large as that in which phenolic odours are detectable. Secondly, they will have to decide on the best measures for decontamination. In areas only slightly contaminated it may be possible to restrict access and to rely on slow microbial and photolytic breakdown. In other areas it could be necessary to remove and bury the topsoil and vegetation. Fire is unlikely to be helpful since T.C.D.D. is stable up to temperatures of 700 °C; only in an efficient incinerator will combustion destroy T.C.D.D. concentrates. The need for care in the disposal of T.C.D.D. residues is evident from American experience. T.C.D.D. wastes were disposed of as a mixture with waste oils and the mix was subsequently used to control dust in horse arenas. 48 out of 85 hor.ses exercised in one arena died, along with other farm animals and local wildlife.16
SURGERY FOR ENDOMYOCARDIAL FIBROSIS
SEVESO THE incident at the Icmesa chemical
plant near Milan hazards associated with the potential highlighted of a synthesis 2,4,5-trichlorophenol, compound used in the preparation of various herbicides and bactericides. The industrial synthesis is relatively simple and involves the alkaline hydrolysis of tetrachlorobenzene at raised temperatures. If the temperature is allowed to exceed 225°C the reaction can become exothermic and the reactor may release its contents explosively. At the same time an unwanted contaminant, 2,3,7,8-tetrachlorodibenzop-dioxin (T.C.D.D.), is formed. T.C.D.D. is solid and in these circumstances would be distributed in a cloud of the
has
droplets. of the most toxic compounds known: in the oral L.D.50 is 0-6 fLg/kg; other species guineapig of laboratory animal are less sensitive.14 Human beings have been exposed in the United States, Germany, and Czechoslovakia, and the Italian experience resembles closely an incident in Derbyshire.15 A common feature in cases of human poisoning is chloracne, a persistent and disfiguring form of acne which has been associated with various chlorinated compounds. Chloracne appears about six weeks after exposure. Other reported symptoms include hirsutism and personality changes, and there can be signs of liver malfunction. The treatment of T.C.D.D. poisoning is purely symptomatic and is complicated by the metabolic and chemical stability of the molecule. These factors, combined with a high lipid/water partition coefficient, mean that T.C.D.D. is concentrated in the liver and fatty tissues; hence the half-life in the body is long. If the release of T.C.D.D. at Seveso is confirmed, the T.C.D.D.
is
one
the
Folkow, B., Neil, E. in Circulation; p. 269. London, 1971. Symon, L. Int. anæsth. Clin. 1969, 7, 597. 14. Schwetz, B. A, Norris, J. M, Sparschu, G. L., Rowe, V. K., Gehring, P. J., Emerson, J. L., Gerbig, C. G. Environ. Hlth Perspectives, 1973, issue 5, p. 87. 15. May, G Br. J md. Med. 1973, 30, 276. 12. 13.
ENDOMYOCARDIAL fibrosis is mainly a disease of tropical regions,17 but the occasional case is seen from temperate parts.18 With medical treatment the prognosis is always grave’9-not surprisingly, since patients usually present with advanced fibrosis of the ventricular inflow tracts extending to the atrioventricular nodes and producing mitral or tricuspid incompetence.17 With left-ventricular lesions, especially when the mitral valve is affected, the prognosis is very poor; the longest survivors19 are patients who present with right-heart lesions, in whom the function of the obliterated right-ventricular cavity is taken over by a high venous pressure made possible by a very tense ascitic abdomen. It is these who show the proptosis and the periorbital congestion typical of the disease. 20 Surgical intervention offers hope of relief. 21 The disease is one in which the heart only is affected, lesions in other organs being secondary. The fibrosis, however extensive on the mural endocardium, is of almost even depth, with the outer portions of the myocardium free of disease and, for the most part, a distinct line of cleavage between the fibrous tissue and the normal myocardium. Finally, thrombosis, even on the fibrosed endocar-
dium, seems distinctly uncommon. The earliest operations in this disease were usually done with a view to relieving pericardial rather than endocardial constriction, and almost all ended disastrously. But with improved methods of diagnosis and strict localisation of the affected areas surgery was possible. Thus Lepley et al. 22
more
definitive
operated on an
Carter, C. D., Kimbrough, R. D., Liddle, J. A., Cline, R. E., Zack, M. M., Barthel, W. F., Koehler, R. E., Phillips, P. E. Science, 1975, 188, 738. 17. Connor, D. H., Somers, K., Hutt, M. S. R., Manion, W. C., D’Arbela, P. G. Am. Heart J. 1967, 74, 687; 1968, 75, 107. 18. Brockington, I. F., Olsen, E. G. J., Goodwin, J. F. Lancet, 1967, i, 583. 19. D’Arbela, P. G., Motazindwa, T., Patel, A. K., Somers, K. Br. Heart J. 1972, 34, 403. 20. Jaiyesmi, F., Falase, A. B. Trop. Cardiol. 1976, 2, 5. 21. Bertrand, E., Renambot, J., Chauvet, J., Assamoi, M. O., Ekra, A. ibid. p. 37. 22. Lepley, D., Aris, A., Korns, M. E., Walker, J. A., D’Cunha, R. M. Ann. thorac. Surg. 1974, 18, 626. 16.
Abortion LAST week’s reportl from the Select Committee on Abortion hardly rates the muscular response on p. 306-some will say. After
all, the Select Com-
mittee does spotlight some of the uglier aspects of abortion in Britain and, if the committee wants to stem the excess of the private market, who (apart from some private "mercenaries of contemporary capitalism"2) will stand in its way? The main proposals are that, in private practice, the two certifying practitioners should not be partners or have a financial interest in the same nursing home or agency; that referral agencies, pregnancy advisory services, and pregnancy-testing agencies which charge fees should have to be licensed; that the upper limit of gestation at the time of termination should in most cases be 20 weeks (as against 28 now); that women witnesses in legal proceedings concerning abortion should be entitled to anonymity ; that police should be able to apply to a judge for permission to inspect documents in agencies and centres charging fees; and that conscientious objection should be made easier for health workers not wishing to be present at an abortion. Some of these suggestions seem unexceptionable. But, en masse, they take on a destructive air. And, as Professor FAIRWEATHER and his co-signatories say, they do not bear on the role of the National Health Service. If more abortions were done on the N.H.S., we would expect less profiteering in the private market: the committee has nothing to say about unequal provision in different parts of the N.H.S.; and, on the matter of abortion clinics, despite its concern for conscientious objectors, it is silent. The proposals on certification would hamper the activities of the best as well as the worst private agencies. The recommendations, in sum, would make it harder for a woman to have her pregnancy skilfully terminated. Would there then be fewer abortions? Women who desire themselves unpregnant will usually find a way. The only change which would certainly lower the abortion-rate is a drop in the number of unintentional pregnancies. Whatever view one takes of the rights of the fetus, the intervention of policemen and licensing authorities seems less than. apt. "Protection" of women (one stated aim of the anti-abortion movement) is at present best achieved by free access to family-planning advice (something we are working towards), with a fall-back on swift and sympathetic termination under the National Health. In those areas where such help is not regarded as part of ordinary medical care, specially staffed clinics must be the answer. In the organisation of such clinics, the N.H.S. could learn much from the charities. 1. First Report from the Select Committee Stationery Office, 1976. 2. White, J Guardian, July 30.
on
Abortion. H.C. 573 - 1. H.M.
CEREBRAL BLOOD-FLOW
CEREBRAL blood-flow was long believed to be governed almost entirely by humoral mechanisms and negligibly by nerves.’ But fresh scrutinyz3 now discloses that neurogenic mechanisms are important after all-particularly in disease states, such as cerebrovascular accidents. After James’s observationthat the sensitivity of cerebral blood-flow to variations in PC02 was enhanced after stellate ganglionectomy and reduced after cervical vagotomy, other workers recorded vasomotor effects on pial and intracerebral vessels in response both to nerve stimulation and to application of neurotransmitters.5-7 All this was evidence of a definite role for vasomotor nerves in the control of cerebral blood-flow, but interpretations differed. Skinhoj8 took the traditional view that sympathetic cerebrovascular vasomotor nerves were silent under normal conditions, their function being to prevent an undue increase in capillary pressure in conditions of extreme vasodilatation brought about by humoral mechanisms. This argument is supported by the observation that the vasoconstrictor effects of stellateganglion stimulation are pH-dependent,2 5 being absent at a pH above 7.45 ([H+] less than 35 nmol/l) but present below 7.40 ([H+] greater than 40 nmol/1). The other extreme was proposed by Mchedlishvili et al.9—namely, that autoregulation of cerebral blood-flow is mediated primarily by neural rather than humoral mechanisms.9 Harper et al.10 held the middle ground and proposed a dual control system for the cerebral circulation, with predominantly neural control of the larger extraparenchymal vessels and predominantly humoral control of the smaller intraparenchymal vessels,10 the two acting as in-series resistances. This would be in accord with prevailing views on the control of the peripheral circulation in most other peripheral beds. These investigations, and the sharply differing interpretations of the results, have led to a resurgence of interest in the neural control of cerebral blood-flow; but the basic issue-the importance of neural mechanisms in the normal regulation of cerebral perfusion2 3-remains unresolved. The elegant histological and pharmacological investigations of Edvinson and his associatesll reveal that parenchymal as well as pial arteries have an abundant nerve supply and that, associated with the vascular smooth muscle of small cerebral arteries and arterioles, there are not only M andadrenergic and cholinergic receptors, but also H1 and H2 histaminergic and serotoninergic receptors. However, as they stress, it would be foolhardy to conclude that the receptors are necessarily associated with the neurons: receptor sites are needed just as much for local humoral or circulating 1.
Ganong,
W. F. in Review of Medical
Physiology; p. 450.
Los
Altos, Califor-
nia, 1973.
2. Lundgren, O., Jodal, M. A. Rev. Physiol. 1975, 37, 395. 3. Obrist, W. D. Clin. Neurosurg. 1975, 22, 106. 4. James, I. M., Miller, R. A., Purves, M. J. Circulation Res., 1969, 25, 77. 5. Wahl, M. ibid. 1972, 31, 248. 6. D’Alecy, L. G., Feigle, E. O. ibid. 1972, 31, 267. 7. Scremin, O. V., Rovere, A. A., Ragnald, A. C., Giordini, A. Stroke, 1973, 8. 9.
4, 232. Skinhøj, E. ibid. 1972, 3, 711. Mchedlishvili, G. I. Mitagvaria, N. P., Ormatsadye, L G ibid. 1973, 4, 742.
A. M., Deshumkel, V. D., Rowan, J. O., Jennett, W. B. Archs Neurol, 1972, 27, 1. 11. Edvinson, L., Owman, C. m Blood Flow and Metabolism in the Brain (edited by A. M. Harper, W. B. Jennett, J. D. Miller, and J. O. Rowan,
10.
Harper,
p. 1. 18. London, 1975.
297
agents as for transmitters of neural origin. Further, their assumption that the much smaller number of nerve fibres going to the vascular smooth muscle in small parenchymal vessels is merely a reflection of the reduced number of muscle fibres requires confirmation by quantitation of nerve/muscle fibre ratios. In other areas of the peripheral systemic vasculature differences in innervation and intermuscular connections correlate with the predominant method of control.12 Such information is required on the cerebral microcirculation if the conflicting views are to be properly appraised. Much remains to be discovered, but the previous simple model for control of cerebral circulation is clearly adequate no longer. Physical and neural factors operate along with the traditional circulating and local humoral agents. Such a multiple-control system will be far more adaptable than a single control loop. If neural mechanisms are important, we must look again at the use of vasoactive drugs in general and localised cerebrovascular disease. Even though such drugs may increase overall cerebral blood-flow, they could well result in a local cerebral steal,13 with reduced flow to an area with already precarious nutrition.
authorities will have two main problems. Firstly, they will have to analyse enough samples to define the amount of T.C.D.D. released and the extent of the contaminated area. Since T.C.D.D. is very firmly bound to soil and is not translocated in groundwaters, the area of contamination is not necessarily as large as that in which phenolic odours are detectable. Secondly, they will have to decide on the best measures for decontamination. In areas only slightly contaminated it may be possible to restrict access and to rely on slow microbial and photolytic breakdown. In other areas it could be necessary to remove and bury the topsoil and vegetation. Fire is unlikely to be helpful since T.C.D.D. is stable up to temperatures of 700 °C; only in an efficient incinerator will combustion destroy T.C.D.D. concentrates. The need for care in the disposal of T.C.D.D. residues is evident from American experience. T.C.D.D. wastes were disposed of as a mixture with waste oils and the mix was subsequently used to control dust in horse arenas. 48 out of 85 hor.ses exercised in one arena died, along with other farm animals and local wildlife.16
SURGERY FOR ENDOMYOCARDIAL FIBROSIS
SEVESO THE incident at the Icmesa chemical
plant near Milan hazards associated with the potential highlighted of a synthesis 2,4,5-trichlorophenol, compound used in the preparation of various herbicides and bactericides. The industrial synthesis is relatively simple and involves the alkaline hydrolysis of tetrachlorobenzene at raised temperatures. If the temperature is allowed to exceed 225°C the reaction can become exothermic and the reactor may release its contents explosively. At the same time an unwanted contaminant, 2,3,7,8-tetrachlorodibenzop-dioxin (T.C.D.D.), is formed. T.C.D.D. is solid and in these circumstances would be distributed in a cloud of the
has
droplets. of the most toxic compounds known: in the oral L.D.50 is 0-6 fLg/kg; other species guineapig of laboratory animal are less sensitive.14 Human beings have been exposed in the United States, Germany, and Czechoslovakia, and the Italian experience resembles closely an incident in Derbyshire.15 A common feature in cases of human poisoning is chloracne, a persistent and disfiguring form of acne which has been associated with various chlorinated compounds. Chloracne appears about six weeks after exposure. Other reported symptoms include hirsutism and personality changes, and there can be signs of liver malfunction. The treatment of T.C.D.D. poisoning is purely symptomatic and is complicated by the metabolic and chemical stability of the molecule. These factors, combined with a high lipid/water partition coefficient, mean that T.C.D.D. is concentrated in the liver and fatty tissues; hence the half-life in the body is long. If the release of T.C.D.D. at Seveso is confirmed, the T.C.D.D.
is
one
the
Folkow, B., Neil, E. in Circulation; p. 269. London, 1971. Symon, L. Int. anæsth. Clin. 1969, 7, 597. 14. Schwetz, B. A, Norris, J. M, Sparschu, G. L., Rowe, V. K., Gehring, P. J., Emerson, J. L., Gerbig, C. G. Environ. Hlth Perspectives, 1973, issue 5, p. 87. 15. May, G Br. J md. Med. 1973, 30, 276. 12. 13.
ENDOMYOCARDIAL fibrosis is mainly a disease of tropical regions,17 but the occasional case is seen from temperate parts.18 With medical treatment the prognosis is always grave’9-not surprisingly, since patients usually present with advanced fibrosis of the ventricular inflow tracts extending to the atrioventricular nodes and producing mitral or tricuspid incompetence.17 With left-ventricular lesions, especially when the mitral valve is affected, the prognosis is very poor; the longest survivors19 are patients who present with right-heart lesions, in whom the function of the obliterated right-ventricular cavity is taken over by a high venous pressure made possible by a very tense ascitic abdomen. It is these who show the proptosis and the periorbital congestion typical of the disease. 20 Surgical intervention offers hope of relief. 21 The disease is one in which the heart only is affected, lesions in other organs being secondary. The fibrosis, however extensive on the mural endocardium, is of almost even depth, with the outer portions of the myocardium free of disease and, for the most part, a distinct line of cleavage between the fibrous tissue and the normal myocardium. Finally, thrombosis, even on the fibrosed endocar-
dium, seems distinctly uncommon. The earliest operations in this disease were usually done with a view to relieving pericardial rather than endocardial constriction, and almost all ended disastrously. But with improved methods of diagnosis and strict localisation of the affected areas surgery was possible. Thus Lepley et al. 22
more
definitive
operated on an
Carter, C. D., Kimbrough, R. D., Liddle, J. A., Cline, R. E., Zack, M. M., Barthel, W. F., Koehler, R. E., Phillips, P. E. Science, 1975, 188, 738. 17. Connor, D. H., Somers, K., Hutt, M. S. R., Manion, W. C., D’Arbela, P. G. Am. Heart J. 1967, 74, 687; 1968, 75, 107. 18. Brockington, I. F., Olsen, E. G. J., Goodwin, J. F. Lancet, 1967, i, 583. 19. D’Arbela, P. G., Motazindwa, T., Patel, A. K., Somers, K. Br. Heart J. 1972, 34, 403. 20. Jaiyesmi, F., Falase, A. B. Trop. Cardiol. 1976, 2, 5. 21. Bertrand, E., Renambot, J., Chauvet, J., Assamoi, M. O., Ekra, A. ibid. p. 37. 22. Lepley, D., Aris, A., Korns, M. E., Walker, J. A., D’Cunha, R. M. Ann. thorac. Surg. 1974, 18, 626. 16.
