929
INTRAVENOUS LABETALOL IN HYPERTENSIVE
having myeloma during the study period. Shown in the accompanying table are age-specific rates by sex for South African and U.S.
(1973-76) Blacks. Age-adjusted rates (1973-75) (world standard) per 100 000 were 7-47 in South African Black males, z 11 in South African Black females and among U.S. Blacks the figures were 752 for males and 5.17 for females, similar to the high rates reported for U.S. Blacks in Detroit, Michigan (males, 5-4, and females 4.8 per 100 000) and in Jamaicans (males, 4.4, and females 3-4). The data may underestimate the incidence in Johannesburg Blacks since some individuals may not seek conventional medical care. The age-adjusted rates for Johannesburg Whites of 7.84 per 100 000 (males) and 4.34 per 100 000 (females) are higher AGE-ADJUSTED
AND STANDARDISED INCIDENCE MYELOMA
RATES*
IN SOUTH AFRICAN AND U.S. BLACKS
*Per 100 000
EMERGENCY
SIR,-Intravenous therapy in the treatment of severe hypertension is seldom required’ and rapid reduction of blood-pressure is not without risk.2 When intravenous therapy i required, labetalol given by incremental infusion3 or bolus injection4 is effective in reducing arterial pressure. However, ij in pressure is required, incremengradual controlled reduction tal infusion is preferred.5 We have discussed elsewhere the relative risks and merits oi available drugs for parenteral use.2,3 In the following case, when the need for intravenous therapy was established, labetalol was used not only to reduce the blood-pressure to a predetermined level but also to prevent undue variability of the blood-pressure during arch aortography The dose was titrated against fluctations in pressure. A 43-year-old male was admitted with severe central ches1 pain of 6 h duration. His blood-pressure was 170/110 mm Hg
(no. of cases in italic type).
than the corresponding rates for U.S. Whites. Local experience suggests the possibility of over-ascertainment because of nonresidents giving a Johannesburg address while receiving medical care in that district. Blacks, because of their residency cards, are more objectively classified as to residence. The results of this study, although based on small numbers, suggest that the high rate for myeloma in Blacks is not limited to America. Reports that healthy native Africans and AfroAmericans have serum-immunoglobulin levels higher than those measured for Whites in the same area,10,11 suggest racial differences in immune response that may be correlated with myeloma risk. Recent’in-vitro studies indicating that Blacks generate predominantly IgG-secreting cells in response to pokeweed mitogen, whereas Whites produce IgM, suggest genetically determined racial differences in immune function.122 Further studies with newly developed probes of immunoregulatory subpopulations may help to characterise racial variations in immune response. Differences in immunoregulation may account not only for the high incidence of myeloma in Blacks but also for differences between races in the occurrence of other B-cell neoplasms, such as chronic lymphocytic leukaemia and some non-Hodgkin’s lymphomas. -
We thank Dr John C. Young, National Cancer Institute, Biometry Branch, Bethesda, for providing incidence data on U.S. Blacks. Environmental Epidemiology Branch, National Cancer Institute, Bethesda, Maryland 20014, U.S.A.
Department of Medicine, Division of Hematology, Georgetown University School of Medicine, Washington, D.C. Department of Clinical Pathology, Milton S. Hershey Medical Center, Hershey, Pennsylvania
WILLIAM A. BLATTNER
Blood-pressure
control with labetalol.
and pulse 56/min. Femoral pulses were poor and periphera pulses were not palpable in the legs... An electrocardiogram die not show any evidence of myocardial infarction but the chest X-ray revealed an enlarged mediastinal shadow suggestive of a dissecting aneurysm of the aorta. Arrangements were made for arch aortography but th( blood-pressure was then found to be 250/154 mm Hg. It wa decided to reduce the blood-pressure gradually to the region 01 160/110 mm Hg by controlled incremental infusion of labetalol before arch aortography. Labetalol was given as shown in the figure, and in 90 mir the target blood-pressure had been achieved. This was maintained by adjusting the dose of labetalol in two ways-firstly. by titrating the dose against the blood-pressure, and secondly by preventing any rise in blood-pressure consequent to an injection of dye by increasing the infusion-rate before the injection.
ROBERT J. JACOBSON 1. Richardson, D. W ., Raper, A J Cardiovasc Clin. 1978, 19, 227. 2. Brown, J. J., Lever, A. F., Cumming, A M. M., Robertson, J I. S. Lancet,
GERALD SHULMAN
10. Shulman, G., Gilich, G. C., Andrew, M. J. A. S. Afr. med. J. 1975, 49, 1160. 11. Buckley, C. E., Dorsey, F. C. Ann. intern. Med. 1971, 75, 673. 12 Ginsburg, W. W., Finkelman, F. D., Lipsky, P. E. J. Immun. 1978, 120, 33.
1977, i, 1147. A. M M., Brown, J J., Fraser, R, Lever, A F, Morton, J. J., Richards, D. A., Robertson, J I. S Br J. clin. Pharmac. (in the press) 4. Trust, P. M., Rosei, E A., Brown, J. J, Fraser, R, Lever, A. F., Morton, J J., Robertson, J. I. S. ibid 1976, 3, 799 5. Cumming, A. M. M, Brown, J. J., Lever, A F., MacKay, A., Robertson, J. I. S. ibid. ,in the press .
3.
Cumming,
930 In this case, gradual reduction of blood-pressure to a given level was required without increasing cardiac output or heartrate. For this reason, diazoxide seemed less suitable? and there have been reports of tachycardia associated with the use of sodium nitroprusside.1-1 The desired effect was achieved by using incremental infusion of labetalol, during which no side-effects were noted. Titrating labetalol and halothane to control blood-pressure under general anxsthesia has been described9,lo but, as far as we are aware, labetalol titration has not been tried in the above circumstances. Arch aortography revealed a dissection extending from the aortic arch to the bifurcation, with dissection under the epicardium but with no evidence of myocardial ischæmia. The patient was treated surgically by ’Dacron’ graft. M.R.C. Blood Pressure Unit and Department of Medicine, Western Infirmary, Glasgow G11 6NT
A. M. M. CUMMING D. L. DAVIES
CHENODEOXYCHOLIC ACID, POSTPRANDIAL SERUM-TRIGLYCERIDES, AND H.D.L. CHOLESTEROL
SIR,-Fasting hypertriglyceridaemia is a risk factor for arterial disease, and is reduced by chenodeoxycholic acid (C.D.C.A.).1,2 This effect is persistent over 6 months, additive to the effect of diet, and equal to the reduction achieved by clofibrate without the lithogenic hazard of this drug.2 It was not known whether this reduction applied to the post-prandial state, which accounts for the major part of the day. Nor was it known whether C.D.C.A. affected high-density lipoprotein (H.D.L.) cholesterol, itself a very powerful predictor of arterial
*P
INTRAVENOUS LABETALOL IN HYPERTENSIVE
having myeloma during the study period. Shown in the accompanying table are age-specific rates by sex for South African and U.S.
(1973-76) Blacks. Age-adjusted rates (1973-75) (world standard) per 100 000 were 7-47 in South African Black males, z 11 in South African Black females and among U.S. Blacks the figures were 752 for males and 5.17 for females, similar to the high rates reported for U.S. Blacks in Detroit, Michigan (males, 5-4, and females 4.8 per 100 000) and in Jamaicans (males, 4.4, and females 3-4). The data may underestimate the incidence in Johannesburg Blacks since some individuals may not seek conventional medical care. The age-adjusted rates for Johannesburg Whites of 7.84 per 100 000 (males) and 4.34 per 100 000 (females) are higher AGE-ADJUSTED
AND STANDARDISED INCIDENCE MYELOMA
RATES*
IN SOUTH AFRICAN AND U.S. BLACKS
*Per 100 000
EMERGENCY
SIR,-Intravenous therapy in the treatment of severe hypertension is seldom required’ and rapid reduction of blood-pressure is not without risk.2 When intravenous therapy i required, labetalol given by incremental infusion3 or bolus injection4 is effective in reducing arterial pressure. However, ij in pressure is required, incremengradual controlled reduction tal infusion is preferred.5 We have discussed elsewhere the relative risks and merits oi available drugs for parenteral use.2,3 In the following case, when the need for intravenous therapy was established, labetalol was used not only to reduce the blood-pressure to a predetermined level but also to prevent undue variability of the blood-pressure during arch aortography The dose was titrated against fluctations in pressure. A 43-year-old male was admitted with severe central ches1 pain of 6 h duration. His blood-pressure was 170/110 mm Hg
(no. of cases in italic type).
than the corresponding rates for U.S. Whites. Local experience suggests the possibility of over-ascertainment because of nonresidents giving a Johannesburg address while receiving medical care in that district. Blacks, because of their residency cards, are more objectively classified as to residence. The results of this study, although based on small numbers, suggest that the high rate for myeloma in Blacks is not limited to America. Reports that healthy native Africans and AfroAmericans have serum-immunoglobulin levels higher than those measured for Whites in the same area,10,11 suggest racial differences in immune response that may be correlated with myeloma risk. Recent’in-vitro studies indicating that Blacks generate predominantly IgG-secreting cells in response to pokeweed mitogen, whereas Whites produce IgM, suggest genetically determined racial differences in immune function.122 Further studies with newly developed probes of immunoregulatory subpopulations may help to characterise racial variations in immune response. Differences in immunoregulation may account not only for the high incidence of myeloma in Blacks but also for differences between races in the occurrence of other B-cell neoplasms, such as chronic lymphocytic leukaemia and some non-Hodgkin’s lymphomas. -
We thank Dr John C. Young, National Cancer Institute, Biometry Branch, Bethesda, for providing incidence data on U.S. Blacks. Environmental Epidemiology Branch, National Cancer Institute, Bethesda, Maryland 20014, U.S.A.
Department of Medicine, Division of Hematology, Georgetown University School of Medicine, Washington, D.C. Department of Clinical Pathology, Milton S. Hershey Medical Center, Hershey, Pennsylvania
WILLIAM A. BLATTNER
Blood-pressure
control with labetalol.
and pulse 56/min. Femoral pulses were poor and periphera pulses were not palpable in the legs... An electrocardiogram die not show any evidence of myocardial infarction but the chest X-ray revealed an enlarged mediastinal shadow suggestive of a dissecting aneurysm of the aorta. Arrangements were made for arch aortography but th( blood-pressure was then found to be 250/154 mm Hg. It wa decided to reduce the blood-pressure gradually to the region 01 160/110 mm Hg by controlled incremental infusion of labetalol before arch aortography. Labetalol was given as shown in the figure, and in 90 mir the target blood-pressure had been achieved. This was maintained by adjusting the dose of labetalol in two ways-firstly. by titrating the dose against the blood-pressure, and secondly by preventing any rise in blood-pressure consequent to an injection of dye by increasing the infusion-rate before the injection.
ROBERT J. JACOBSON 1. Richardson, D. W ., Raper, A J Cardiovasc Clin. 1978, 19, 227. 2. Brown, J. J., Lever, A. F., Cumming, A M. M., Robertson, J I. S. Lancet,
GERALD SHULMAN
10. Shulman, G., Gilich, G. C., Andrew, M. J. A. S. Afr. med. J. 1975, 49, 1160. 11. Buckley, C. E., Dorsey, F. C. Ann. intern. Med. 1971, 75, 673. 12 Ginsburg, W. W., Finkelman, F. D., Lipsky, P. E. J. Immun. 1978, 120, 33.
1977, i, 1147. A. M M., Brown, J J., Fraser, R, Lever, A F, Morton, J. J., Richards, D. A., Robertson, J I. S Br J. clin. Pharmac. (in the press) 4. Trust, P. M., Rosei, E A., Brown, J. J, Fraser, R, Lever, A. F., Morton, J J., Robertson, J. I. S. ibid 1976, 3, 799 5. Cumming, A. M. M, Brown, J. J., Lever, A F., MacKay, A., Robertson, J. I. S. ibid. ,in the press .
3.
Cumming,
930 In this case, gradual reduction of blood-pressure to a given level was required without increasing cardiac output or heartrate. For this reason, diazoxide seemed less suitable? and there have been reports of tachycardia associated with the use of sodium nitroprusside.1-1 The desired effect was achieved by using incremental infusion of labetalol, during which no side-effects were noted. Titrating labetalol and halothane to control blood-pressure under general anxsthesia has been described9,lo but, as far as we are aware, labetalol titration has not been tried in the above circumstances. Arch aortography revealed a dissection extending from the aortic arch to the bifurcation, with dissection under the epicardium but with no evidence of myocardial ischæmia. The patient was treated surgically by ’Dacron’ graft. M.R.C. Blood Pressure Unit and Department of Medicine, Western Infirmary, Glasgow G11 6NT
A. M. M. CUMMING D. L. DAVIES
CHENODEOXYCHOLIC ACID, POSTPRANDIAL SERUM-TRIGLYCERIDES, AND H.D.L. CHOLESTEROL
SIR,-Fasting hypertriglyceridaemia is a risk factor for arterial disease, and is reduced by chenodeoxycholic acid (C.D.C.A.).1,2 This effect is persistent over 6 months, additive to the effect of diet, and equal to the reduction achieved by clofibrate without the lithogenic hazard of this drug.2 It was not known whether this reduction applied to the post-prandial state, which accounts for the major part of the day. Nor was it known whether C.D.C.A. affected high-density lipoprotein (H.D.L.) cholesterol, itself a very powerful predictor of arterial
*P
