[Neuro-hormonal mechanisms in heart failure -- from physiopathology to treatment]

This review updates some recent advances of a new and exciting developments in basic and clinical cardiology: a) the role, in the congestive heart failure (CHF), of the neurohumoral systems (NHS) which act to maintain circulatory homeostatic equilibrium, and b) the therapeutic implications of such a role. Six NHS, acting in CHF, have presently been identified: three of them induce vasoconstriction and sodium retention (sympathetic nervous systems, renin-angiotensin-aldosterone system and arginine-vasopressine system); the remaining three offset or balance the former ones, acting, therefore as "counterregulators" (prostaglandins--PGE2 and PGI2--, dopaminergic system and atrial natriuretic factor). Each one of these NHS influences the "compensatory" mechanisms of heart failure, acting on the target-organs both by direct effects and by interaction with other NHS; consequently, in heart failure, all the NHS are stimulated with the respective increase in the plasma levels of their active agents. In asymptomatic stages of ventricular dysfunction the stimulation of the vasodilator-and-natriuretic systems appears to be predominant and able to maintain circulatory equilibrium. However, as the heart dysfunction increases and becomes symptomatic, the vasoconstrictor and sodium-retaining forces appear to predominate; this phenomenon becomes increasingly apparent as the functional class becomes more advanced. The hyperstimulation of these last systems has an extremely important role in the pathophysiology and clinical manifestations of congestive heart failure, as well as in its prognosis. Therefore, the attempts to correct these neurohormonal imbalance in patients with heart failure has a sound rational basis, not only to improve the symptoms and the exercise capacity but also to increase the survival of these patients. At the present time, amongst the potential pharmacological interventions acting on NHS in CHF, the blockade of the RAA system with ACE-inhibitors is generally accepted as the most feasible, the safest and the most effective therapeutic tool. In fact, its application has broadened from an earlier use in severe CHF to other symptomatic stages of cardiac failure, including the milder forms. In addition, preliminary data strongly suggest its unique usefulness in asymptomatic phase of ventricular dysfunction. Looking back at the medical therapy of heart failure, in can be concluded that we are starting a new era. Throughout 200 years (since the introduction of digitalis) the therapeutic goal in CHF has been the improvement of symptoms. With the developments of the present decade, a new and exciting goal is being offered to these patients, called by Packer "the second frontier", that is, the prolongation of their lives.

Renal dopaminergic mechanisms in renal parenchymal diseases, hypertension, and heart failure

The recovery of renal function in renal transplant recipients is accompanied by an enhanced ability to synthesize dopamine (DA), which may contribute to maintain sodium homeostasis. Patients suffering from chronic renal parenchymal disease, a well-recognized form of salt sensitive (SS) hypertension, have a reduced ability to produce DA that correlates well with deterioration of renal function. In patients afflicted with IgA nephropathy, but normal renal function, urinary excretion of DA correlated positively with BP responses to changes from 200 to 20 mmol/day salt intake. In black salt resistant (SR) normotensives (NT) and SR hypertensives, under low salt intake (40 mmol/day), but not SS-NT and SS-HT, the saline infusion induced increments of DA and DOPAC urinary excretion correlated significantly with increments of sodium urinary excretion and sodium fractional excretion. Patients afflicted with heart failure (HF) have a reduced delivery of L-DOPA to the kidney, accompanied by an increase in DA/L-DOPA urinary ratios. This suggests that HF patients have an increased ability to take up or decarboxylate L-DOPA. Sodium restriction resulted in a significant decrease in urinary L-DOPA, DA and DOPAC in HF patients, suggesting that the system responds to sodium. It is concluded that activity of renal dopaminergic system may be altered in SS subjects, despite the level of their BP, and an enhanced delivery of L-DOPA to the kidney may be beneficial in edema formation states.

Influence of salt intake on the daytime-nighttime blood pressure variation in normotensive and hypertensive black subjects

OBJECTIVE

To evaluate the influence of different salt-intake regimens on the circadian rhythm of blood pressure (daytime-night-time relationship) in normotensive and hypertensive black subjects with different patterns of salt sensitivity.

METHODS

Randomized, cross-over study. Twenty normotensive (NT) and 27 hypertensive (HT) black subjects were kept on a low-sodium diet (30 mmol sodium/d, LS) and on a high-sodium diet (300 mmol sodium/d, HS) for 1 week each. On the last day of each regimen, 24 hour ambulatory blood pressure monitoring was performed.

RESULTS

Eight normotensives were classified as salt-sensitive (SS), all with haptoglobin phenotypes (FeHap) 1,1 or 1,2, and 12 as salt resistant (SR), 5 with FeHap 2,2. Seventeen hypertensives were classified as SS, all with FeHap 1,1 or 1,2, and 11 as SR, 2 with FeHap 2,2. Salt sensitivity criterium was: difference > 5 mmHg of 24 h mean blood pressure from low sodium to high sodium. The pattern of daytime-nighttime blood pressure relationship between LS and HS was only modified (respectively from dipper to non-dipper) in HT-SS, but not in NT-SS, NT-SR and HT-SR. The percentual drop in nighttime mean blood pressure was about 10% in HT-SR and in NT-SR either under LS or HS. In NT-SS, the percentual night-time drop in mean blood pressure was lower than that of NT-RS (i.e. about 7-8%), but it was not different on LS and on HS. In contrast, in HT-SS, the percentual nighttime drop in mean blood pressure on HS (6%) was significantly lower than that on LS (10%, p < 0.01). In the 27 HT, but not in the NT, changes in the nocturnal drop in mean blood pressure induced by salt restriction correlated positively with the degree of salt sensitivity (r = 0.45, p < 0.05).

CONCLUSIONS

In black subjects, the pattern of nighttime-daytime blood pressure relationship appears to be modified from LS to HS diets (or vice-versa) only in SS hypertensive subjects, but neither in NT-SS nor in NT-SS and HT-SR. Only in HT-SS, but not in the other groups, salt restriction shifts the circadian rhythm of blood pressure from a non-dipper to a dipper pattern. We conclude that in black salt-sensitive hypertensives, salt restriction improves the circadian rhythm of blood pressure. This may have important therapeutic consequences on target organ damage associated with non-dipper patterns.

Arterial distensibility in subjects with white-coat hypertension with and without diabetes or dyslipidaemia: comparison with normotensives and sustained hypertensives

BACKGROUND

Arterial distensibility can be assessed by measuring pulse-wave velocity (PWV).

OBJECTIVE

To determine whether diabetes, smoking and dyslipidaemia were associated with greater than normal stiffness of aortic walls in subjects with white-coat hypertension.

METHODS

Arterial distensibility was assessed by automatic measurement of carotid-femoral PWV in 35 healthy normotensives, 46 white-coat hypertensives (WCH, clinic blood pressures >140/90 mm Hg, daytime blood pressures <130/85 mm Hg) and 81 ambulatory hypertensives (clinic blood pressures >140/90 mmHg, daytime blood pressures > or =130 mm Hg systolic or > or =85 mm Hg diastolic, or both) all matched for age, sex and body mass index. Nineteen normotensives (subgroup A), 28 WCH (subgroup A) and 37 ambulatory hypertensives (subgroup A) had only one or no other major cardiovascular risk factor whereas 16 normotensives (subgroup B), 18 WCH (subgroup B) and 44 ambulatory hypertensives (subgroup B) had also some combination of non-insulin-dependent diabetes, a smoking habit and dyslipidaemia.

RESULTS

Both for the WCH and for ambulatory hypertensives diabetes and dyslipidaemia (subgroups B) were associated with higher (P<0.04) PWV (11.6+/-0.3 and 12.8+/-0.3m/s, respectively) than for subgroups A (9.3+/-0.5 and 10.9+/-0.6 m/s, respectively). In contrast, PWV for WCH in subgroup A (9.3+/-0.5m/s) did not differ (P>0.35) from those for the normotensive subgroups A (9.2+/-0.3m/s) and B (9.6+/-0.4m/s). PWV was not correlated to levels of glycaemia, glycosylated haemoglobin and cholesterolaemia.

CONCLUSIONS

These results suggest that, both for ambulatory hypertensives and for WCH, diabetes and dyslipidaemia are associated with an impairment of arterial distensibility that can entail a greater than normal cardiovascular risk, which might dictate a more than usually stringent treatment of concomitant risk factors and possibly of high blood pressure. In contrast, PWV in WCH of the subgroup A did not differ from those in normotensives, reinforcing the hypothesis that WCH is associated with a benign cardiovascular outcome in the absence of other cardiovascular risk factors.

Deficiency of renal dopaminergic-dependent natriuretic response to acute sodium load in black salt-sensitive subjects in contrast to salt-resistant subjects

OBJECTIVE

To evaluate the involvement of the renal dopaminergic system in the natriuretic responses to acute saline load in salt-resistant (SR) and salt-sensitive (SS) black normotensive (NT) and hypertensive (HT) subjects.

DESIGN AND METHODS

We studied the relationship between the urinary excretion of dopa, dopamine (DA) and its metabolite DOPAC and the natriuretic responses to acute volume expansion (2 l NaCl 0.9% over 2 h) in 20 black NT subjects (12 SR and 8 SS) and 19 black HT subjects (10 SS and 9 SR). Subjects received a low salt (LS) diet (40 mmol sodium/day) for 1 week and a high salt (HS) diet (300 mmol sodium/day) for 1 week; the sequence of the dietary regimens was randomized. Comparisons were made between the results before the saline infusion (baseline) and the results 2 h after the infusion.

RESULTS

In all the groups saline infusion induced significant increases in urinary volume (ml/4 h) of two- to three-fold and in urinary sodium excretion (mmol/4 h) of three- to ten-fold; these increases were significantly greater during the HS diet than during the LS diet. Saline infusion significantly increased the mean arterial pressure (MAP) by 5 mmHg in HT-SS subjects and by 4-5 mmHg in NT-SS subjects, but the MAP did not changed in the NT-SR and HT-SR groups. Under the LS diet, saline infusion changed the DA excretion (in nmol/4 h) by -49+/-89 in HT-SS subjects, by 17+/-52 in NT-SS subjects, by 235+/-72 in HT-SR subjects and by 220+/-86 in NT-SR subjects (P < 0.05 between SR and SS subjects). The saline infusion-induced changes in DA excretion correlated significantly with the increases in urinary sodium excretion (r = 0.71, P < 0.01) in the NT-SR and HT-SR subjects under the LS diet, but not in the SR groups on the HS diet nor in the SS groups (HT and NT) on either diet. Saline infusion significantly reduced the DA/dopa ratio in SS (NT and HT) but not SR (NT and HT) subjects, whereas the DA/DOPAC (dihydroxyphenylacetic acid) ratios were similar in all the groups.

CONCLUSIONS

The urinary dopaminergic system may participate in the natriuretic responses to acute sodium load only in SR subjects (NT and HT) and only under LS diets, but not in SS subjects (NT and HT). This strongly suggests that black NT- and HT-SS subjects have an underlying impairment in the activity of the renal dopaminergic system which may be associated with a reduced decarboxylation of dopa into DA.

Acute hypotensive, natriuretic, and hormonal effects of nifedipine in salt-sensitive and salt-resistant black normotensive and hypertensive subjects

In a randomized double-blind study, we compared the short-term effects of nifedipine (10 mg 3x daily for 1 day) versus placebo on 24-h blood pressure, diuresis, natriuresis, urinary excretion of dopamine and metabolites, and on plasma renin activity (PRA) and plasma aldosterone levels in 18 black hypertensive (HT) patients [eight salt-resistant (HT-SR) and 10 salt-sensitive (HT-SS)], and in 20 black normotensive (NT) subjects (12 NT-SR and eight NT-SS) who were studied randomly with both a high- (HS) and a low-salt (LS) diet. In comparison to placebo, nifedipine significantly decreased 24-h mean BP in all groups either with HS or LS diets (all p<0.05). With HS, greater hypotensive effects were achieved in NT-SS (-10+/-2 mm Hg) versus NT-SR (-3+/-1 mm Hg; p<0.05) and in HT-SS (-18+/-2 mm Hg) versus HT-SR (-12+/-2 mm Hg; p<0.05). In NT-SS and HT-SS, nifedipine induced greater (p<0.05) BP decrease with HS (-10+/-2 and -18+/-2 mm Hg) than with LS (-4+/-1 and -9+/-1 mm Hg, respectively), whereas in NT-SR and HT-SR, the hypotensive effect did not differ between HS and LS. Nifedipine versus placebo significantly increased natriuresis and fractional excretion of sodium in all groups only with HS (p<0.05) but not with LS diets. Only in HT-SS were the hypotensive and natriuretic effects of nifedipine significantly correlated (r = -0.77; p<0.01). Nifedipine produced a similar increase of the urinary excretion of dopamine, L-DOPA, and of DOPAC in all subjects, which did not correlate with hypotensive and natriuretic effects. Nifedipine did not modify plasma levels of renin and of aldosterone except in NT-SS with HS, in whom nifedipine increased PRA levels (p <0.05). We conclude that although nifedipine reduces BP in all groups of NT and HT with LS and HS diets, the effect is greater in salt-sensitive subjects with HS. Although in HT-SS with HS, the short-term natriuretic response to nifedipine may contribute to its hypotensive effects, the diuretic-natriuretic effect of nifedipine is not necessary for the expression of its hypotensive effect. Moreover, it is unlikely that any short-term effects of nifedipine either on the renal dopaminergic system or on the secretion of aldosterone explain nifedipine short-term hypotensive and diuretic-natriuretic effects.

Nail changes secondary to docetaxel (Taxotere)

Docetaxel is a new taxoid antineoplastic drug widely used for advanced breast cancer. Skin and nail toxicity are one of the more frequent nonhematologic adverse reactions. Besides dark pigmentations and Beau's lines, subungual hemorrhage, orange discoloration, acute painful paronychia, onycholysis, subungual hyperkeratosis and transverse loss of the nail plate are described. The type of nail alteration is related with the number of cycles administered and there are no efficacious preventive measures to avoid its development. Clinicians should recognize the clinical picture of these adverse nail reactions because docetaxel is used for several neoplastic disorders.

Brain natriuretic peptide as a marker of cardiac involvement in hypertension

Hypertensive patients with heart abnormalities have increased risk of cardiovascular events. Brain natriuretic peptide is a natriuretic peptide mainly of ventricular origin produced in response to pressure and stretch. We hypothesise that brain natriuretic peptide could be a useful marker of cardiac remodelling in hypertensive patients. We studied 36 consecutive community mild-to-moderate hypertensive patients and 11 well-matched normotensive controls with respect to clinical characteristics, brain natriuretic peptide, creatinine and echocardiography parameters (M-mode, 2-D arid transmitral pulsed Doppler). Brain natriuretic peptide levels were significantly higher in hypertensive patients than in controls [36.54 (IQR: 38.61) vs. 10.30 (IQR: 13.20) pg ml(-1), p<0.0001] and it was correlated with left ventricular mass index. Hypertensive patients with impairment of diastolic filling had significantly higher brain natriuretic peptide concentrations than patients with no abnormalities on echocardiography [61.16 (45.38) vs. 31.27 (18.10) pg ml(-1), p=0.001]. Multivariate analysis showed that only diastolic dysfunction and left ventricular mass index were significantly and independently related with brain natriuretic peptide concentrations in this population. In conclusion, impairment of diastolic function and left ventricular mass index are related to brain natriuretic peptide levels, thus giving the insight that this peptide can be a marker of ventricular remodelling in hypertensive patients.

Differences in behavior profile between normotensive subjects and patients with white-coat and sustained hypertension

It has been hypothesized that white-coat hypertensives (WCHs) have lower cardiovascular risk than sustained hypertensives (HTs), but higher emotional reactivity. We evaluated 92 HT patients (clinic and daytime BP>140/90 mmHg), 52 WCHs (clinic BP>140190 and ambulatory daytime BP<134/ 85 mmHg), and 74 normotensive subjects (NTs, clinic BP<140/90 and ambulatory daytime BP<134/85 mmHg), aged between 24 and 72 years, and matched for educational level, age, gender, and weight for depression, psychopathology, well-being, and quality of life. HTs showed worse scores than WCHs and NTs on most of the psychological variables; no differences were found between WCHs and NTs except on physical mobility. Daytime BP variability was HTs>WCHs>NTs, whereas nighttime BP variability was HTs>WCHs=NTs. We conclude that HTs have worse psychological profiles than the other two groups. WCHs and NTs have similar psychological profiles, although WCHs have a higher daytime BP variability, which is not associated with higher emotional reactivity.

[The additional efficacy of the nifedipine-diuretic combination depends on the potency of the drug administered first and not the sequence of administration. A double blind study in salt-sensitive black hypertensives]

OBJECTIVE

To evaluate whether the additional antihypertensive efficacy of the nifedipine-thiazide combination depends on the sequence of drug administration and whether the natriuretic effect of thiazide persists when co-administered with nifedipine.

METHODS

Double blind, randomised, crossover, placebo-controlled study, in 12 salt-sensitive hypertensive black patients (SSH). Evaluation of the antihypertensive (24 h ambulatory monitoring) and natriuretic effects of placebo (PL), of nifedipine-GITS (NIF, 30 mg/d) and of hydrochlorothiazide (HCTZ, 25 mg/d) given alone and in combination within two separate therapeutic sequences: PL-->NIF-->NIF + HCTZ and PL-->HCTZ-->HCTZ + NIF (1 month for each therapeutic regimen).

RESULTS

NIF induced greater (p < 0.04) reduction of 24 h mean arterial pressure (MAP) (-15.9 +/- 1.9 mm Hg, v PL) than HCTZ (-9.0 +/- 1.3 mm Hg). The association of NIF to HCTZ induced a greater (p < 0.05) additional reduction of MAP-24 h (9.7 +/- 2.2 mm Hg) than that produced by the association of HCTZ to NIF (4.1 +/- 1.3 mm Hg). NIF alone and in combination did not modify the diuresis-natriuresis observed with the previous treatment, whereas HCTZ alone and in combination always increased diuresis (by 25%) and natriuresis (by 53%). There was a significant negative correlation (r = -0.71, p < 0.001) between blood pressure (BP) reduction induced by the drug administered first (NIF or HCTZ) and the additional BP reduction obtained by the association of the second drug.

CONCLUSIONS

In most of the SSH the NIF-GITS was more potent than HCTZ. NIF did not modify the diuretic-natriuretic effect of PL and of HCTZ. The greater potency of NIF may explain why in most patients the combination HCTZ to NIF induced a lower hypotensive effect than that of the association of NIF to HCTZ. Independently of the sequence of the drug administration, the lower the hypotensive effect of the drug administered first the greater the additional hypotensive effect that was observed by adding the second drug.

Nifedipine-retard versus nifedipine-capsules for the therapy of hypertensive crisis in black patients

In a randomized parallel-group placebo-controlled study, we compared the short-term hypotensive efficacy and the safety of a single administration of nifedipine-retard (20-mg tablets) with that of two administrations 6 h apart of nifedipine capsules (10 mg) in 10 and 11 black patients, respectively, with acute severe hypertension. Both groups had similar pretreatment blood-pressure (BP) values. Blood pressure was recorded at 10-min intervals for 12 h by using an automated device. In the first 3 h of treatment, nifedipine capsules induced a faster and greater hypotensive effect than nifedipine retard, which was associated with an increase in heart rate. At 2 h after treatment, nifedipine capsules decreased BP to levels (159 +/- 5/105 +/- 3 mm Hg) that were significantly lower than those reached by nifedipine-retard (175 +/- 4/118 +/- 4 mm Hg; p < 0.05). Both preparations induced a similar maximal BP decrease of approximately 30% of the placebo values, but the peak decrease of BP occurred significantly later with nifedipine-retard (283 +/- 31 min after administration) than with nifedipine capsules (100 +/- 14 min; p < 0.01). Four hours after administration, the hypotensive effect of nifedipine capsules was blunted, and a second administration was necessary, whereas nifedipine-retard reduced BP slowly and continuously for < or =12 h and more smoothly. Flush and headache were more frequently found with nifedipine capsules. We conclude that in black patients with hypertensive crisis, nifedipine capsules produce an abrupt decrease in BP that may be potentially harmful. Thus for patients suitable for treatment with nifedipine, nifedipine-retard is preferable because it effectively reduces BP for > or =12 h while achieving a rapid enough effect without critical short-term decreases in BP.

Interaction of antihypertensive drugs with anti-inflammatory drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) can induce an increase in blood pressure (BP) and may potentially reduce the efficacy of several antihypertensive drugs. Probably the main mechanism of action is inhibition of prostaglandin (PG) synthesis since NSAIDs have higher propensity to increase BP as the regulation of BP (and renal function) is more PG-dependent and to interact with drugs (diuretics, beta-blockers and ACE inhibitors) that may act through the increase of PG formation. In contrast, NSAIDs do not interact with calcium antagonists and central acting drugs which actions are apparently unrelated with renal/extrarenal production of PG. It has been claimed that inhibition of natriuretic PGs could explain the pressure effects of NSAIDs in treated hypertensive patients, but sodium retention may be not the single explanation for such an interaction. We found that despite indomethacin produced sodium retention after being added either to enalapril or nifedipine-GITS, it only attenuated (by 45%) the antihypertensive effects of enalapril. In alternative, since PG enhances vasodilatation and attenuates vasoconstrictor influences, some NSAIDs may counteract the PG-dependent vasodilatory tone in renal and extrarenal vascular beds that mediate the antihypertensive action of some drugs. Thus, since calcium antagonists are probably not affected by NSAIDs, they may be preferable to drugs like diuretics, beta-blockers and ACE inhibitors for the treatment of high blood pressure control in hypertensive patients who are clinically suitable for NSAIDs therapy.

Low-dose oral contraceptives and 24-hour ambulatory blood pressure

OBJECTIVE

To evaluate in normotensive women the influence of low-dose oral contraceptives (OC, monophasic formulations containing 30 microg of estrogen) on 24-h blood pressure.

METHODS

We evaluated prospectively in 15 normotensive healthy women (three smokers) the influence of OC on 24-h ambulatory blood pressure monitoring (ABPM). ABPM was performed (SpaceLabs 90207) before and after 6-9 months of use of OC. We also evaluated ABPM in eight women (two smokers) before and after 6-8 months on an intrauterine device (IUD) as contraceptive method--these were used as control subjects.

RESULTS

OC produced a significant increase in 24-h ABPM values (from 120+/-3/75+/-2 to 128+/-4/81+/-2 mmHg, P < 0.04) which was particularly evident for night-time values (from 108+/-2/64+/-2 to 120+/-4/73+/-2 mmHg, P < 0.02). After OC, two normotensive women developed 'hypertensive values'. In OC users there was a slight but significant increase in body weight which did not correlate with the increase of blood pressure. In contrast, in the control group (IUD) neither ABPM values nor weight were modified by the contraceptive maneuver.

CONCLUSIONS

In normotensive women, low-dose OC may increase blood pressure to an extent that, at least in some women, may affect blood pressure control towards 'hypertensive values'. This stresses the importance of monitoring blood pressure values during OC treatment.

Efficacy of captopril and nifedipine in black and white patients with hypertensive crisis

We examined the antihypertensive efficacy of: (1) sublingual-oral single doses of captopril (25 mg) and nifedipine-capsules (10 mg) in 9 + 9 white patients and in 9 + 8 black patients with hypertensive crisis; and (2) a single oral dose of the slow-acting preparation of nifedipine-retard (20 mg) in another 10 black patients. Blood pressure (BP) was assessed at 10 min intervals for 6 h after administration. After 6 h, the BP falls induced by these drugs were still significantly lower than the baseline placebo values. Hypotensive effect of nifedipine-capsules was established more rapidly than that of captopril in both white and black patients, and of nifedipine-retard in black patients. Considering the area under the curve of BP values during the 6-h treatment, the overall hypotensive effect of nifedipine-capsules was similar to captopril in white patients, but significantly more pronounced than captopril and nifedipine-retard in black patients. In white patients similar maximal drops of BP (mean+/-s.e.m.) were obtained with nifedipine-capsules (71+/-4/52+/-4 mm Hg) and with captopril (69+/-4/50+/-3 mm Hg). In black patients the maximal drop of BP of nifedipine-capsules (70+/-4/52+/-4 mm Hg) was greater (P < 0.02) than that of captopril (48+/-4/32+/-3 mm Hg) but similar to that of nifedipine-retard (71+/-4/49+/-4 mm Hg). However, in contrast to nifedipine-capsules and captopril, nifedipine-retard produced a slower drop in BP. The time of peak drop in BP of both nifedipine-capsules and captopril occurred within the first 2 h whereas with nifedipine-retard it occurred only between 4 and 6 h after administration. Fewer patients reported side effects with nifedipine-retard as compared with the other two preparations. We conclude that single doses of captopril and nifedipine reduces BP for at least 6 h in both white and black patients with hypertensive crisis, but nifedipine is more potent than captopril in black patients. The slow release form of nifedipine-retard effectively and safely lowers BP while achieving a rapid enough effect without the critical rapid falls in BP that occur with nifedipine-capsules.

Evaluation of the sympathetic nervous system using heart rate variability and plasma hormones in hypertensive patients treated with cilazapril and atenolol

In a double-blind placebo-controlled parallel study, we assessed basal and post-therapeutic sympathetic activity both in supine and standing positions in mildly to moderately hypertensive patients by two different methods: frequency domain indices of heart rate variability (HRV) and plasma levels of both noradrenaline (NA) and its metabolite, 3,4-dihydroxyphenylglycol (DOPEG). Patients were evaluated on placebo and after 8 weeks of treatment with either cilazapril, 2.5-5 mg/day (13 patients) or atenolol, 50-100 mg/day (14 patients). Twenty-four-hour blood pressure was similarly reduced (p < 0.01) by both cilazapril and atenolol. Heart rate decreased with atenolol by 14 beats per min (p < 0.001) but did not change with cilazapril. When compared to the placebo, cilazapril did not modify sympathetic activity indices of HRV but did significantly reduce NA and DOPEG levels in both the supine and standing (p < 0.05) positions. As expected, atenolol reduced (p < 0.05) sympathetic activity indices of HRV but did not modify NA levels in either position. Moreover, while on placebo, patients showed no significant correlations between values of NA or DOPEG, nor in any of the HRV indices. We conclude that: (1) the antihypertensive effects of cilazapril and atenolol are similar, but in these patients, sympathetic activity indices showed divergent results both before and after therapy; (2) this may be due to different aspects of sympathetic activators, assessed independently by different methods, and (3) these discrepancies must be taken into account when evaluating autonomous nervous system parameters.

[Reduction of the antihypertensive effects of enalapril by indomethacin. Its independence from renal sodium retention]

OBJECTIVE

To evaluate in hypertensive patients whether or not the sodium-retaining effects of indomethacin can explain the indomethacin-induced attenuation of enalapril antihypertensive effects.

DESIGN

Randomized, single-blinded, placebo controlled study with a placebo phase (2 weeks) followed by enalapril 20 mg/d (4 weeks, once daily) and enalapril 20 mg + indomethacin 75 mg/d (1 week). Enalapril dose increased up to 40 mg/d if inadequate response to 20 mg.

PATIENTS

Twenty-four patients with mild-moderated hypertension, showing an adequate response to enalapril (20-40 mg/d).

METHODS

Blood pressure evaluated by "casual" methods and by 24-hour ambulatory blood pressure monitoring, measurement of 24-hour urinary sodium excretion and fractional excretion of sodium: at the end of placebo, enalapril and enalapril + indomethacin treatments. Determination of the correlations between the changes induced by indomethacin (when added to enalapril) on the blood pressure and on sodium excretion effects of enalapril.

RESULTS

Enalapril significantly reduced casual blood pressure (systolic/diastolic) by 33/18 mmHg and 24-hour blood pressure by 20/9 mmHg. When added to enalapril, indomethacin attenuated (by 50%) the antihypertensive effects of enalapril and significantly decreased the 24-hour (from 120 +/- 11 mmol to 106 +/- 10 mmol) and fractional excretion of sodium (from 1.11 +/- 0.09% to 0.75 +/- 0.06%). However, the indomethacin-induced attenuation of enalapril hypotensive effects did not correlate with indomethacin-induced changes of sodium excretion.

CONCLUSIONS

When indomethacin is administrated to hypertensive patients that are well controlled with enalapril, it produces a marked attenuation of enalapril hypotensive effects and produces sodium retention. However, the amount of the attenuation of the hypotensive effects of enalapril by indomethacin are completely independent of the amount of the indomethacin-induced sodium retention. These results suggest that the mechanisms involved in interaction between both drugs at the blood pressure domain are probably localized at an extra-renal level.

Lisinopril and diltiazem reduce left ventricular mass without changing blood pressure in normotensive subjects with exaggerated blood pressure response to exercise

OBJECTIVE

To determine whether high left ventricular mass may be reduced by antihypertensive drugs in normotensives with exaggerated blood pressure response to exercise as it occurs in hypertensive patients.

DESIGN AND METHODS

Randomized, single blind, controlled parallel study evaluating the influence of placebo; lisinopril 20 mg/day, diltiazem 180 mg/d for 5-6 months on left ventricular mass (LVM), evaluated by echo and on "casual" and 24-h ambulatory blood pressure (24-h BP) in normotensive subjects with exaggerated blood pressure response to exercise (Group I) and in weight--and age--matched mild-moderated hypertensive patients (Group II), all with high left ventricular mass.

PATIENTS

Placebo, lisinopril and diltiazem, were administered for 5-6 months in respectively 8+9+9 subjects of Group I and 8+9+10 patients in Group II.

RESULTS

Placebo did not change either LVM index or 24-h BP values in Group I and Group II. Diltiazem and lisinopril reduced LVM index in both Groups I and II but 24-h BP values were only reduced in Group II. Lisinopril appeared to be more potent than diltiazem on LVM regression. Slopes of LVM index regression were not different between Groups I and II for each drug. Drug-induced changes of LVM index did not correlate with blood pressure changes.

CONCLUSIONS

Drug-induced regression of LVM may be achieved in man (Group I) without any reduction of blood pressure. This may be explained by interference with growth-promoting systems other than with cardiac unloading. Also, the similar pattern of LVM regression that was observed in both Groups I and II suggests that similar underlying mechanisms may be involved in the LVH regression in these two populations.

Influence of non-steroidal anti-inflammatory drugs on renal function and 24h ambulatory blood pressure-reducing effects of enalapril and nifedipine gastrointestinal therapeutic system in hypertensive patients

OBJECTIVE

To evaluate the influence of non-steroidal anti-inflammatory drugs (NSAIDs; aspirin and indomethacin) on the renal and antihypertensive effects of enalapril and nifedipine gastrointestinal therapeutic system (GITS) in patients with essential hypertension.

DESIGN AND METHODS

In a crossover study, 18 patients on an unrestricted-salt diet were randomly assigned to receive either enalapril (20-40 mg/day) or nifedipine-GITS (30-60 mg/day) for 4-8 weeks, followed by aspirin (100 mg/day for 2 weeks) and then indomethacin (75 mg/day for 1 week). Blood pressure was measured by 24h ambulatory monitoring.

RESULTS

Enalapril and nifedipine-GITS significantly reduced blood pressure compared with placebo. Aspirin did not alter the antihypertensive effect of either drug. Indomethacin attenuated (by 45%) the antihypertensive effect of enalapril throughout the 24h period of evaluation, but did not interfere with the effect of nifedipine. Furthermore, indomethacin significantly reduced the fractional excretion of sodium and plasma levels of prostaglandins in a similar way when added to either the enalapril or the nifedipine regimen.

CONCLUSIONS

Vasodilatory prostaglandins are probably involved in the antihypertensive effects of enalapril but not of nifedipine, and this interaction seems to be independent of any indomethacin-induced decrease in renal sodium excretion. Nifedipine may be an appropriate drug to treat hypertensive patients requiring concomitant therapy with NSAID.

Measurement of trough-to-peak ratios of four anti-hypertensive drugs on the basis of 24 h ambulatory blood pressure monitoring: different methods may give different results

With 24 h ambulatory blood pressure monitoring (ABPM), the trough-to-peak (T/P) ratios (corrected for placebo) of atenolol 100 mg, cilazapril 2.5 mg, enalapril 20 mg and nifedipine-GITS 30 mg administered once daily for 4 weeks were determined in four groups of hypertensive patients. T/P ratios were calculated by three different methods: directly from the curves that averaged all individual 24 h profiles (A); averaging all individual T/P ratios after ABPM data were averaged for each patient over either 1 h intervals (B) or 3 h intervals (C). Methods B and C produced different values of T/P which, for each drug, were significantly higher with method C. With method A, nifedipine appeared to have the higher T/P. With methods B and C (which in contrast to method A, permitted statistical comparisons), differences between nifedipine and the other drugs were not significant. Meanwhile, method B appears to adhere most closely to FDA guidelines by taking more into account the interindividual variability of BP profile. Thus, we suggest that precise guidelines for measuring T/P on the basis of ABPM are needed, whereas for the comparison between drugs, both the mean value of the T/P and its variance must be determined.

[Use of spreadsheet for statistical and graphical processing of records from the ambulatory blood pressure monitor Spacelabs 90207]

The introduction of portable devices for non-invasive ambulatory blood-pressure measurement is recognized as an advance in the study of human arterial hypertension, allowing a significant improvement in the selection of hypertensive patients as well as in the analysis of the effects of antihypertensive drugs during clinical trials. The Spacelabs 90207 is a recent example of this kind of apparatus, possessing high levels of portability and being highly classified in validation studies. Nevertheless, the software of this apparatus (like other similar devices) has severe limitations in what concerns the calculation of the area under the curve of blood pressure during the time of measurement, as well as in the possibility of grouping several records in a database for easy statistic and graphic analysis of different groups of records. In order to overcome these difficulties, the authors describe the development of a group of programs, using Microsoft Excel v3.0 spreadsheets and macros, that allow a direct import of individual files from the Spacelabs software to a spreadsheet and its further processing in three phases. These three phases, which we designated by "conversion", "export to database" and "statistic and graphic analysis", will permit an easy and fast statistic and graphic analysis of selected groups of records.

Severe acute form of adult dermatomyositis treated with cyclosporine

The classical treatment of severe forms of dermatomyositis includes high doses of steroids and/or cytotoxic agents. Acute forms are frequently life threatening. Because cyclosporine is a fast-acting immunosuppressive drug, it appears to be a good candidate for the treatment of refractory forms of acute dermatomyositis. We report a dramatic improvement of a severe, acute, steroid-resistant adult form after cyclosporine administration. A rapid clinical and biochemical improvement is reported, and the reversibility of immunologic abnormalities is emphasized.

Long-term administration of 1,3-dipropyl-8-sulfophenylxanthine causes arterial hypertension

Adenosine has been shown recently to be the main factor responsible for the trophic effects of sympathetic innervation. As sympathetic denervation causes hypertrophic and hyperplastic changes reminiscent of those occurring in blood vessels of spontaneously hypertensive rats, we decided to study the effect of a continuous blockade of adenosine receptors on both blood vessel structure and blood pressure. A continuous infusion of 1,3-dipropyl-8-sulfophenylxanthine (DPSPX; 30 micrograms/kg per h for 7 days) to Wistar rats caused hyperplastic changes in peritoneal fibroblasts and mesenteric arterioles, hypertrophic changes in the smooth muscle of the tail artery and significant increase in the size of left ventricle myocardial cell nuclei. Both diastolic and systolic blood pressure increased significantly above control values. The results confirmed the trophic effects of adenosine and showed that chronic blockade of adenosine receptors causes arterial hypertension.

[Neuro-hormonal mechanisms in heart insufficiency--from physiopathology to treatment]

This review updates some recent advances of a new and exciting developments in basic and clinical cardiology: a) the role, in the congestive heart failure (CHF), of the neurohormonal systems (NHS) which act to maintain circulatory homeostatic equilibrium, and b) the therapeutic implications of such a role. Six NHS, acting in CHF, have presently been identified: three of them induce vasoconstriction and sodium retention (sympathetic nervous systems, renin-angiotensin-aldosterone system and arginine-vasopressine system); the remaining three offset or balance the former ones, acting, therefore as "counterregulators" (prostaglandins--PGE2 and PGI2--, dopaminergic system and atrial natriuretic factor). Each one of these NHS influences the "compensatory" mechanisms of heart failure, acting on the target-organs both by direct effects and by interaction with other NHS; consequently, in heart failure, all the NHS are stimulated with the respective increase in the plasma levels of their agents. In asymptomatic stages of ventricular dysfunction the stimulation of the vasodilator-and-natriuretic systems appears to be predominant and able to maintain circulatory equilibrium. However, as the heart dysfunction increases and becomes symptomatic, the vasoconstrictor and sodium-retaining forces appear to predominate; this phenomenon becomes increasingly apparent as the functional class becomes more advanced. The hyperstimulation of these last systems has an extremely important role in the pathophysiology and clinical manifestations of congestive heart failure, as well as in its prognosis. Therefore, the attempts to correct these neurohormonal imbalance in patients with heart failure has a sound rational basis, not only to improve the symptoms and the exercise capacity but also to increase the survival of these patients. At the present time, amongst the potential pharmacological interventions acting on NHS in CHF, the blockade of the SRA system with ACE-inhibitors is generally accepted as the most feasible, the safer and the most effective therapeutic tool. In fact, its application has broadened from an earlier use in severe CHF to other symptomatic stages of cardiac failure, including the milder forms. In addition, preliminary data strongly suggest its unique usefulness in asymptomatic phases of ventricular dysfunction. Looking back at the medical therapy of heart failure, it can be concluded that we are starting a new era. Throughout 200 years (since the introduction of digitalis) the therapeutic goal in CHF has been the improvement of symptoms. With the developments of the present decade, a new and exciting goal is being offered to these patients, called by Packer "the second frontier", that is, the prolongation of their lives.

Effects of phenethyl alcohol on Bacillus and Streptococcus

The activity of phenethyl alcohol (PEA) on Bacillus cereus, B. megaterium, and Streptococcus faecalis was studied by electron microscopy of thin sections and by the assay of intracellular K+ leakage. S. faecalis was unaffected by PEA at concentrations up to 0.5%, B. cereus was severely damaged by 0.5% PEA, and B. megaterium behaved intermediately. Important membrane ultrastructural alterations were observed in B. cereus cells treated with 0.5% PEA, namely the change in the geometry of the membrane profile from asymmetric to symmetric, the occurrence of prominent, complex mesosome-like structures, and membrane fracturing and solubilization. Protoplasts from B. megaterium were found to be quickly lysed by 0.5% PEA due to the disruption of the cytoplasmic membrane. The electron microscopic observations, together with the results of the study of the K+ efflux from B. cereus and B. megaterium, indicate that PEA primarily and directly damages the cytoplasmic membrane of sensitive bacteria. The breakdown of the permeability barrier probably is responsible for the observed bactericidal action of 0.5% PEA on B. cereus.

Isolation of pinastric acid and ergosterol from Parmelia caperata (L.) Arch

Among other common compounds, pinastric acid and ergosterol were isolated for the first time from Parmelia caperata. The isolation of these compounds is described; identification was made from the melting point and UV, IR, and mass spectral data.

Preparation and pharmacological activity of the condensation product of adrenaline with acetaldehyde

In vitro incubation of adrenaline with acetaldehyde resulted in the formation of an amorphous product (MA 3) which gave origin to two spots on chromatography plates. Preparative TLC allowed us to separate the corresponding substances, MA 4 and MA 5. Gas chromatography-mass spectrometry, ultraviolet and infrared spectra of MA 4 agree with the structure corresponding to 1,2-dimethyl-4,6,7-trihydroxy-1,2,3,4-tetrahydroisoquinoline. MA 5 is very unstable and was not further characterized. Pharmacological experiments were carried out with MA 3 and MA 4 (and in some cases, MA 5) on isolated saphenous vein strips and isolated guinea-pig atria; responses of the nictitating membrane, blood pressure and hind-limb perfusion pressure were obtained in the anaesthetized dog. There were only quantitative differences between the effects of MA 3, MA 4 and MA 5 (where tested). Therefore, these effects are described as effects of TIQs (tetrahydroisoquinolines). TIQs contracted isolated saphenous vein strips, behaving as total agonists; the dose-response curves were displaced to the right by phentolamine and to the left by cocaine (potentiation factor: 2.7 +/- 0.1). In the dog, contractions of the nictitating membrane, rises of blood pressure and of the perfusion pressure (after i.a. injection) were observed. On isolated guinea-pig atria, weak beta adrenergic receptor activation was found. With higher concentrations, beta receptor blockade was observed, for both cardiac and vascular smooth muscle receptors. The effects of TIQs were short-lasting, showing that a rapid inactivation occured both in vitro and in vivo; neuronal uptake appears to play an important role in inactivation, since cocaine was able to block about 70% of the inactivation capacity of isolated vein strips. The effects of nerve stimulation on the vein strips or on the nictitating membrane were reduced by TIQs; however, this did not affect responses to noradrenaline and enhanced those to tyramine or DMPP. Simultaneously with reduction of the effects of electrical stimulation, blockade of inactivation of endogenous and exogenous noradrenaline was induced by TIQs. Marked depletion of noradrenaline levels in the heart, hypothalamus and aorta of the guinea pig was caused by MA 3 (1-3 mg/kg). It is concluded that the condensation products of adrenaline with acetaldehyde are not devoid of pharmacological activity, are taken up by adrenergic nerve terminals and may act as false transmitters. The similarity of effects of TIQs and acetaldehyde suggests that formation of TIQs may occur in vivo, after acetaldehyde (or ethanol) administration, both in the adrenal gland and in sympathetic nerve terminals. These TIQ alkaloids could play an important role in alcoholic intoxication and in the ethanol withdrawal syndrome.