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"New" natriuretic peptides and blood pressure
Letters to the Editor
"New" natriuretic peptides and blood pressure SiR-Natriuretic peptides may be markers of left-ventricular dysfunction.1,2 Brain natriuretic peptide (BNP), a cardiac hormone despite its name, may also be a marker of left ventricular hypertrophy (LVH) because plasma BNP is raised in hypertrophic cardiomyopathy. We measured BNP by radioimmunoassay in 29 untreated hypertensives (mean blood pressure 168/101 mm Hg) and in 25 age and sex matched normotensives from the general population. Hypertensive patients had normal renal function and electrocardiograms. In the same plasma samples, C-type natriuretic peptide (CNP) was also measured. CNP is a neuropeptide that is also synthesised in vascular endothelium.4 In rats, CNP lowers blood pressure when given systemically. Its function in man is unknown. CNP relaxes vascular smooth muscle and inhibits proliferation through activation of the guanylate-cyclasecoupled atrial natriuretic peptide B receptor. Thus CNP may complement the actions of nitric oxide and oppose those of endothelin in regulating vascular tone and remodelling. The plasma concentration of BNP was significantly higher in hypertensive patients than in normotensives (mean [SE] 6-32
[0.39] 5-04 [0-33] pmol/L, p 0-02, unpairedt test). Multiple regression showed that plasma BNP was significantly related to systolic blood pressure and age (figure). Plasma CNP was 1-14 (0-08) pmol/L in controls and 1-10 (0-08) pmol/L in hypertensives (p 0-76). Plasma CNP was significantly related to sex, heart rate, and alcohol intake, but was independent of age, bodyweight, and blood pressure. To investigate the correlation with heart rate further, noradrenaline and adrenaline were measured in the original plasma samples of 18 untreated hypertensive patients. Neither BNP nor CNP correlated significantly with adrenaline. CNP, but not BNP, correlated significantly with plasma noradrenaline (r=0-54, p = 0-04). Plasma BNP and CNP were not correlated (r = 0-24,
p = 0’11), indicating
BM
Y Cheung,
r=043,p=0002.
984
have different
M J Brown
1
2
3
4
5
6
Lerman A, Gibbons RJ, Rodeheffer RJ, et al. Circulating N-terminal atrial natriuretic peptide as a marker for symptomless left-ventricular dysfunction. Lancet 1993; 341: 1105-09. Motwani JG, McAlpine H, Kennedy N, Struthers AD. Plasma brain natriuretic peptide as an indicator for angiotensin-converting-enzyme inhibition after myocardial infarction. Lancet 1993; 341: 1109-10. Yoshibayashi M, Kamiya T, Saito Y, Matsuo H. Increased plasma levels of brain natriuretic peptide in hypertrophic cardiomyopathy. N Engl J Med 1993; 329: 433-34. Stingo AJ, Clavell AL, Heublein DM, et al. Presence of C-type natriuretic peptide in cultured human endothelial cells and plasma. Am J Physiol 1992; 263: H1318-21. Liebson PR, Grandits G, Prineas R, et al. Echocardiographic correlates of left ventricular structure among 844 mildly hypertensive men and women in the treatment of mild hypertension study (TOMHS). Circulation 1993; 87: 476-86. Kohno M, Horio T, Yokokawa K, et al. Brain natriuretic peptide as a cardiac hormone in essential hypertension. Am J Med 1992; 92: 29-34.
Punctures in
adjusted for age against
peptides
Clinical Pharmacology Unit, Department of Medicine, Level 2, Block F & G, Addenbrooke’s Hospital, Cambridge CB2 2QQ, UK
=
Plasma BNP (pmol/L) systolic blood pressure
two
recent TOMHS study’ showed that a significant proportion of hypertensive patients with normal electrocardiograms have LVH, and BNP correlates strongly with LVH .6 Therefore, plasma BNP in hypertensive patients may be an early measure of target-organ damage in those who have a normal electrocardiogram, and thus may provide an alternative to hospital-based echocardiography for assessing early LVH sequentially. By contrast with BNP but like another endothelial peptide, endothelin, plasma CNP was not raised in hypertension. The correlation with noradrenaline but not adrenaline is intriguing, since it has previously been difficult to demonstrate endothelial cell regulation by a neurotransmitter.
=
Figure:
that these
roles. The
surgical gloves
SIR-Orthopaedic surgeons use "double gloving" because they worry about infection risks for the patient. Double gloves are also recommended for operations on HIV-infected patients because punctured gloves may cause concern to staff. The additional gloves provide extra protection by reducing the perforation rate in the inner glove. Identification of glove punctures allows the surgeon to take appropriate precautions. If double-gloving is used a simple (and now patented) way to. detect glove punctures is to use a coloured inner glove to visualise the ingress of blood or body fluids (figure). We tested a prototype coloured glove (Regent Hospital Products) worn beneath a standard glove (Biogel, Regent). Gloves were examined by the surgeon and changed if seen to be punctured. All gloves were retrieved and tested for punctures in the laboratory by water pressure. The study involved twenty-five orthopaedic operations lasting from 30 to 120 min (median 62) in which 148 outer gloves were used by three surgeons. 29 glove punctures were found in the laboratory, 23 of which were seen during the operation by the surgeons, who also queried punctures in 6 gloves that were not confirmed by
"New" natriuretic peptides and blood pressure SiR-Natriuretic peptides may be markers of left-ventricular dysfunction.1,2 Brain natriuretic peptide (BNP), a cardiac hormone despite its name, may also be a marker of left ventricular hypertrophy (LVH) because plasma BNP is raised in hypertrophic cardiomyopathy. We measured BNP by radioimmunoassay in 29 untreated hypertensives (mean blood pressure 168/101 mm Hg) and in 25 age and sex matched normotensives from the general population. Hypertensive patients had normal renal function and electrocardiograms. In the same plasma samples, C-type natriuretic peptide (CNP) was also measured. CNP is a neuropeptide that is also synthesised in vascular endothelium.4 In rats, CNP lowers blood pressure when given systemically. Its function in man is unknown. CNP relaxes vascular smooth muscle and inhibits proliferation through activation of the guanylate-cyclasecoupled atrial natriuretic peptide B receptor. Thus CNP may complement the actions of nitric oxide and oppose those of endothelin in regulating vascular tone and remodelling. The plasma concentration of BNP was significantly higher in hypertensive patients than in normotensives (mean [SE] 6-32
[0.39] 5-04 [0-33] pmol/L, p 0-02, unpairedt test). Multiple regression showed that plasma BNP was significantly related to systolic blood pressure and age (figure). Plasma CNP was 1-14 (0-08) pmol/L in controls and 1-10 (0-08) pmol/L in hypertensives (p 0-76). Plasma CNP was significantly related to sex, heart rate, and alcohol intake, but was independent of age, bodyweight, and blood pressure. To investigate the correlation with heart rate further, noradrenaline and adrenaline were measured in the original plasma samples of 18 untreated hypertensive patients. Neither BNP nor CNP correlated significantly with adrenaline. CNP, but not BNP, correlated significantly with plasma noradrenaline (r=0-54, p = 0-04). Plasma BNP and CNP were not correlated (r = 0-24,
p = 0’11), indicating
BM
Y Cheung,
r=043,p=0002.
984
have different
M J Brown
1
2
3
4
5
6
Lerman A, Gibbons RJ, Rodeheffer RJ, et al. Circulating N-terminal atrial natriuretic peptide as a marker for symptomless left-ventricular dysfunction. Lancet 1993; 341: 1105-09. Motwani JG, McAlpine H, Kennedy N, Struthers AD. Plasma brain natriuretic peptide as an indicator for angiotensin-converting-enzyme inhibition after myocardial infarction. Lancet 1993; 341: 1109-10. Yoshibayashi M, Kamiya T, Saito Y, Matsuo H. Increased plasma levels of brain natriuretic peptide in hypertrophic cardiomyopathy. N Engl J Med 1993; 329: 433-34. Stingo AJ, Clavell AL, Heublein DM, et al. Presence of C-type natriuretic peptide in cultured human endothelial cells and plasma. Am J Physiol 1992; 263: H1318-21. Liebson PR, Grandits G, Prineas R, et al. Echocardiographic correlates of left ventricular structure among 844 mildly hypertensive men and women in the treatment of mild hypertension study (TOMHS). Circulation 1993; 87: 476-86. Kohno M, Horio T, Yokokawa K, et al. Brain natriuretic peptide as a cardiac hormone in essential hypertension. Am J Med 1992; 92: 29-34.
Punctures in
adjusted for age against
peptides
Clinical Pharmacology Unit, Department of Medicine, Level 2, Block F & G, Addenbrooke’s Hospital, Cambridge CB2 2QQ, UK
=
Plasma BNP (pmol/L) systolic blood pressure
two
recent TOMHS study’ showed that a significant proportion of hypertensive patients with normal electrocardiograms have LVH, and BNP correlates strongly with LVH .6 Therefore, plasma BNP in hypertensive patients may be an early measure of target-organ damage in those who have a normal electrocardiogram, and thus may provide an alternative to hospital-based echocardiography for assessing early LVH sequentially. By contrast with BNP but like another endothelial peptide, endothelin, plasma CNP was not raised in hypertension. The correlation with noradrenaline but not adrenaline is intriguing, since it has previously been difficult to demonstrate endothelial cell regulation by a neurotransmitter.
=
Figure:
that these
roles. The
surgical gloves
SIR-Orthopaedic surgeons use "double gloving" because they worry about infection risks for the patient. Double gloves are also recommended for operations on HIV-infected patients because punctured gloves may cause concern to staff. The additional gloves provide extra protection by reducing the perforation rate in the inner glove. Identification of glove punctures allows the surgeon to take appropriate precautions. If double-gloving is used a simple (and now patented) way to. detect glove punctures is to use a coloured inner glove to visualise the ingress of blood or body fluids (figure). We tested a prototype coloured glove (Regent Hospital Products) worn beneath a standard glove (Biogel, Regent). Gloves were examined by the surgeon and changed if seen to be punctured. All gloves were retrieved and tested for punctures in the laboratory by water pressure. The study involved twenty-five orthopaedic operations lasting from 30 to 120 min (median 62) in which 148 outer gloves were used by three surgeons. 29 glove punctures were found in the laboratory, 23 of which were seen during the operation by the surgeons, who also queried punctures in 6 gloves that were not confirmed by