- Email: [email protected]
HALOTHANE ANAESTHETIC AND THE OZONE LAYER
719
(88-3-1=57 per 1000 per year). This suggests that the potential benefit of a policy of reducing serum total cholesterol, in terms of the number of major IHD events postponed or prevented for a given number of men, is greater in men with a previous myocardial infarction than it is in
men
with
no
evidence of IHD. In this
important sense serum total cholesterol is a major risk factor for new IHD events in men with a previous myocardial infarction. The reduction of serum total cholesterol in these men may be at least as important as it is in men without evidence of IHD. Department of Clinical Epidemiology and General Practice,
A. N. PHILLIPS A. G. SHAPER
Royal Free Hospital School of Medicine, London NW3 2PF
AN, Shaper AG, Pocock SJ, Walker M, MacFarlane PW. The role of risk factors in heart attacks occurring in men with pre-existing ischaemic heart disease. Br Heart J 1988; 60: 404-10.
1. Phillips
SIR,-Your thoughtful editorial rightly emphasises that the influence of myocardial damage on prognosis after infarction is often far greater than that of the levels of plasma cholesterol or low-density lipoprotein cholesterol. But this should not be used as an argument against the need for lipid-lowering drugs in the special situation of secondary prevention after coronary artery bypass surgery-a subject not mentioned in the editorial. The evidence of more frequent graft closure in patients with continuing high blood cholesterol is convincing.! The only two secondary prevention trials with marginally positive results (the post trial follow-up of the Coronary Drug Project2 and the open Swedish trial3) used nicotinic acid. The Coronary Drug Project is frequently cited as support for the cholesterol hypothesis. But nicotinic acid has two actions more impressive than cholesterol reduction. One is triglyceride lowering: this may be especially relevant since it might lead to an antithrombotic effect, in view of the correlation between triglyceride levels and factor VIIC4 and tissue plasminogen activator inhibitor.s The other is that nicotinic acid has vasodilator and haemodynamic effects, which could act in the long term by reducing myocardial work. Both actions could improve morbidity in patients with coronary heart disease independently of any effect on cholesterol levels and, uniquely, reduce mortality also. Cardiovascular Research Unit, University of Edinburgh, Hugh Robson Building, George Square,
M. F. OLIVER
Edinburgh EH8 9XE
Campeau L, Enjalbert M, Lesperance J, et al. The relation of risk factors to the development of atherosclerosis in saphenous vein bypass grafts and the progression of disease in the native circulation. N Engl J Med 1984; 311: 1329-32. 2. Canner PL, Berge KG, Wenger NK, et al. Co-operative studies. Fifteen year mortality in Coronary Drug Project patients: long-term benefit with niacin. JACC 1986; 8: 1.
1245-55. 3. Carlson LA, Rosenhamer G. Reduction of mortality in the Stockholm Ischaemic Heart Disease Secondary Prevention Study by combined treatment with clofibrate and nicotinic add. Acta Med Scand 1988; 223: 405-18. 4. Mitropoulous KA. Hypercoagulability and factor VII in hypertriglycendemia. Sem Thromb Haemost 1988; 14: 246-52. 5. Hamsten A, Wiman B, DeFaire U, et al. Increased plasma levels of a rapid inhibitor of tissue plasminogen activator in young survivors of myocardial infarction. N Engl J Med 1985; 313: 1557-63
transmission is primarily related to the mother’s serum HBV-DNA at delivery and that measurement of maternal HBV-DNA permits prediction of how effective hepatitis B immunisation will be in preventing mother-infant HBV transmission perinatally or postnatally. However, we did not, as Ip et al claim, suggest that high maternal serum HBV-DNA levels predict intrauterine HBV infection. We found that the titres of HBV-DNA in the sera of carrier mothers at delivery did not parallel those in their babies at birth, and intrauterine transmission of HBV was unlikely for most high-risk infants.3 If transmission of HBV occurs in utero hepatitis B immunisation at birth will fail. HBV infection in infants born to HBeAg-carriers with high serum levels of HBV-DNA can be avoided by caesarean section-to reduce the amounts of HBV through perinatal transinission together with passive and active immunisation at birth4-or by increasing the dose of HBIG at birth to neutralise what may be large amounts of HBV from carrier mothers, followed by active immunisation.5
SHOU-DONG LEE Division of Gastroenterology,
Department of Medicine, Veterans General Hospital, Taipei, Taiwan 11217, Republic of China
KWANG-JUEI Lo YANG-TE TSAI JAW-CHING WU
1. Beasley RP, Hwang LY, Lee GCY, et al. Prevention of preinatally transmitted hepatitis B virus infections with hepatitis B immune globulin and hepatitis B vaccine. Lancet 1983; ii: 1099-102. 2. Lo KJ, Tsai YT, Lee SD, et al. Immunoprophylaxis of infection with hepatitis B virus in infants born to hepatitis B surface antigen-positive carrier mothers. J Infect Dis
1985; 152: 817-22. SD, Lo KJ, Wu JC, et al. Prevention of maternal-infant hepatitis B virus transmission by immunization: the role of serum hepatitis B virus DNA. Hepatohgy 1986; 6: 369-73. 4. Lee SD, Lo KJ, Tsai YT, et al. Role of caesarean section in prevention of mother-infant transmission of hepatitis B virus. Lancet 1988; ii: 833-34. 5. Schalm SW, Pit-Grosheide P. Prevention of hepatitis B transmission at birth. Lancet 1989; i: 44. 3. Lee
HALOTHANE ANAESTHETIC AND THE OZONE LAYER
SIR,-Volatile chlorofluorocarbons (CFC) have been breaking ozone layer and many countries now have laws or guidelines for the use of CFC gases. Industry is being encouraged to develop less harmful alternatives. Halothane is a CFC, and the Montreal protocol on agents breaking down the ozonosphere
down the
includes halothane. Halothane has a destructive effect upon the ozone layer about one-third of that of the ’Freon’ series of CFCs. Enflurane and isoflurane may also be under suspicion too. Halothane use (and that of the other agents mentioned) is small beside the pollution from industry. Nevertheless it is an area where doctors could help to lessen damage to the ozonosphere. There are alternatives to volatile anaesthetic agents, such as total intravenous anaesthesia and regional anaesthesia. We do not seek to condemn the use of volatile anaesthetic agents because of their influence on the environment, but rather to create a discussion as to how doctors can contribute to the avoidance of atmospheric pollution.
J. NØRRESLET Department of Anaesthesia, Vejle Hospital, DK-7100 Vejle, Denmark
S. FRIBERG T. M. NIELSEN U. RØMER
MATERNAL HEPATITIS B VIRUS DNA IN MOTHER-INFANT TRANSMISSION
EARLY DETECTION OF BREAST CANCER IN
SiR,—Transmission of hepatitis B virus (HBV) from a mother to her baby can be interrupted by combined passive/active immunisation. However, 25% of infants born to e antigen (HBeAg) carrier mothers who received HBV vaccine alone and 10-15% of the high-risk infants who received vaccine plus hepatitis B immunoglobulin (HBIG) at birth are still at risk of HBV
SiR,—Randomised trials in western countries indicate that screening for early detection of breast cancer, especially by mammography, can reduce mortality from this disease; and there is optimism that such a public health policy might be an effective method for controlling breast cancer.1 Although the incidence of breast cancer is generally lower in developing countries than elsewhere, ahnost half of the world’s breast cancer toll will be in the developing areas.2 As competing causes of death decrease, breast cancer is likely to become an even greater public health challenge in the Third World. Unfortunately, there has been little discussion of strategies for controlling breast cancer in the developing world and
DEVELOPING COUNTRIES
infecrion.1,2 Dr
Ip and colleagues (Feb 25,
p
406) found that infants of
HBeAg-carrier mothers with high serum levels of at a
HBV-DNA
are
significant risk of HBV infection even if they have been given
vaccine. This
finding accords with our observation3 that the risk of
(88-3-1=57 per 1000 per year). This suggests that the potential benefit of a policy of reducing serum total cholesterol, in terms of the number of major IHD events postponed or prevented for a given number of men, is greater in men with a previous myocardial infarction than it is in
men
with
no
evidence of IHD. In this
important sense serum total cholesterol is a major risk factor for new IHD events in men with a previous myocardial infarction. The reduction of serum total cholesterol in these men may be at least as important as it is in men without evidence of IHD. Department of Clinical Epidemiology and General Practice,
A. N. PHILLIPS A. G. SHAPER
Royal Free Hospital School of Medicine, London NW3 2PF
AN, Shaper AG, Pocock SJ, Walker M, MacFarlane PW. The role of risk factors in heart attacks occurring in men with pre-existing ischaemic heart disease. Br Heart J 1988; 60: 404-10.
1. Phillips
SIR,-Your thoughtful editorial rightly emphasises that the influence of myocardial damage on prognosis after infarction is often far greater than that of the levels of plasma cholesterol or low-density lipoprotein cholesterol. But this should not be used as an argument against the need for lipid-lowering drugs in the special situation of secondary prevention after coronary artery bypass surgery-a subject not mentioned in the editorial. The evidence of more frequent graft closure in patients with continuing high blood cholesterol is convincing.! The only two secondary prevention trials with marginally positive results (the post trial follow-up of the Coronary Drug Project2 and the open Swedish trial3) used nicotinic acid. The Coronary Drug Project is frequently cited as support for the cholesterol hypothesis. But nicotinic acid has two actions more impressive than cholesterol reduction. One is triglyceride lowering: this may be especially relevant since it might lead to an antithrombotic effect, in view of the correlation between triglyceride levels and factor VIIC4 and tissue plasminogen activator inhibitor.s The other is that nicotinic acid has vasodilator and haemodynamic effects, which could act in the long term by reducing myocardial work. Both actions could improve morbidity in patients with coronary heart disease independently of any effect on cholesterol levels and, uniquely, reduce mortality also. Cardiovascular Research Unit, University of Edinburgh, Hugh Robson Building, George Square,
M. F. OLIVER
Edinburgh EH8 9XE
Campeau L, Enjalbert M, Lesperance J, et al. The relation of risk factors to the development of atherosclerosis in saphenous vein bypass grafts and the progression of disease in the native circulation. N Engl J Med 1984; 311: 1329-32. 2. Canner PL, Berge KG, Wenger NK, et al. Co-operative studies. Fifteen year mortality in Coronary Drug Project patients: long-term benefit with niacin. JACC 1986; 8: 1.
1245-55. 3. Carlson LA, Rosenhamer G. Reduction of mortality in the Stockholm Ischaemic Heart Disease Secondary Prevention Study by combined treatment with clofibrate and nicotinic add. Acta Med Scand 1988; 223: 405-18. 4. Mitropoulous KA. Hypercoagulability and factor VII in hypertriglycendemia. Sem Thromb Haemost 1988; 14: 246-52. 5. Hamsten A, Wiman B, DeFaire U, et al. Increased plasma levels of a rapid inhibitor of tissue plasminogen activator in young survivors of myocardial infarction. N Engl J Med 1985; 313: 1557-63
transmission is primarily related to the mother’s serum HBV-DNA at delivery and that measurement of maternal HBV-DNA permits prediction of how effective hepatitis B immunisation will be in preventing mother-infant HBV transmission perinatally or postnatally. However, we did not, as Ip et al claim, suggest that high maternal serum HBV-DNA levels predict intrauterine HBV infection. We found that the titres of HBV-DNA in the sera of carrier mothers at delivery did not parallel those in their babies at birth, and intrauterine transmission of HBV was unlikely for most high-risk infants.3 If transmission of HBV occurs in utero hepatitis B immunisation at birth will fail. HBV infection in infants born to HBeAg-carriers with high serum levels of HBV-DNA can be avoided by caesarean section-to reduce the amounts of HBV through perinatal transinission together with passive and active immunisation at birth4-or by increasing the dose of HBIG at birth to neutralise what may be large amounts of HBV from carrier mothers, followed by active immunisation.5
SHOU-DONG LEE Division of Gastroenterology,
Department of Medicine, Veterans General Hospital, Taipei, Taiwan 11217, Republic of China
KWANG-JUEI Lo YANG-TE TSAI JAW-CHING WU
1. Beasley RP, Hwang LY, Lee GCY, et al. Prevention of preinatally transmitted hepatitis B virus infections with hepatitis B immune globulin and hepatitis B vaccine. Lancet 1983; ii: 1099-102. 2. Lo KJ, Tsai YT, Lee SD, et al. Immunoprophylaxis of infection with hepatitis B virus in infants born to hepatitis B surface antigen-positive carrier mothers. J Infect Dis
1985; 152: 817-22. SD, Lo KJ, Wu JC, et al. Prevention of maternal-infant hepatitis B virus transmission by immunization: the role of serum hepatitis B virus DNA. Hepatohgy 1986; 6: 369-73. 4. Lee SD, Lo KJ, Tsai YT, et al. Role of caesarean section in prevention of mother-infant transmission of hepatitis B virus. Lancet 1988; ii: 833-34. 5. Schalm SW, Pit-Grosheide P. Prevention of hepatitis B transmission at birth. Lancet 1989; i: 44. 3. Lee
HALOTHANE ANAESTHETIC AND THE OZONE LAYER
SIR,-Volatile chlorofluorocarbons (CFC) have been breaking ozone layer and many countries now have laws or guidelines for the use of CFC gases. Industry is being encouraged to develop less harmful alternatives. Halothane is a CFC, and the Montreal protocol on agents breaking down the ozonosphere
down the
includes halothane. Halothane has a destructive effect upon the ozone layer about one-third of that of the ’Freon’ series of CFCs. Enflurane and isoflurane may also be under suspicion too. Halothane use (and that of the other agents mentioned) is small beside the pollution from industry. Nevertheless it is an area where doctors could help to lessen damage to the ozonosphere. There are alternatives to volatile anaesthetic agents, such as total intravenous anaesthesia and regional anaesthesia. We do not seek to condemn the use of volatile anaesthetic agents because of their influence on the environment, but rather to create a discussion as to how doctors can contribute to the avoidance of atmospheric pollution.
J. NØRRESLET Department of Anaesthesia, Vejle Hospital, DK-7100 Vejle, Denmark
S. FRIBERG T. M. NIELSEN U. RØMER
MATERNAL HEPATITIS B VIRUS DNA IN MOTHER-INFANT TRANSMISSION
EARLY DETECTION OF BREAST CANCER IN
SiR,—Transmission of hepatitis B virus (HBV) from a mother to her baby can be interrupted by combined passive/active immunisation. However, 25% of infants born to e antigen (HBeAg) carrier mothers who received HBV vaccine alone and 10-15% of the high-risk infants who received vaccine plus hepatitis B immunoglobulin (HBIG) at birth are still at risk of HBV
SiR,—Randomised trials in western countries indicate that screening for early detection of breast cancer, especially by mammography, can reduce mortality from this disease; and there is optimism that such a public health policy might be an effective method for controlling breast cancer.1 Although the incidence of breast cancer is generally lower in developing countries than elsewhere, ahnost half of the world’s breast cancer toll will be in the developing areas.2 As competing causes of death decrease, breast cancer is likely to become an even greater public health challenge in the Third World. Unfortunately, there has been little discussion of strategies for controlling breast cancer in the developing world and
DEVELOPING COUNTRIES
infecrion.1,2 Dr
Ip and colleagues (Feb 25,
p
406) found that infants of
HBeAg-carrier mothers with high serum levels of at a
HBV-DNA
are
significant risk of HBV infection even if they have been given
vaccine. This
finding accords with our observation3 that the risk of