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Biomedical subjects

H Herlitz

Publications and source records attributed to H Herlitz.

At least 73 records · Page 4Linked to original sources
PubMed1990

Differential effects of captopril and enalapril, two angiotensin converting enzyme inhibitors, on immune reactivity in experimental lupus disease.

We have previously demonstrated that Captopril, an inhibitor of angiotensin converting enzyme (ACE), ameliorates experimental systemic lupus erythematosus in inbred MRL lpr/lpr (MRL/l) mice. In contrast, Enalapril, another ACE inhibitor with antihypertensive properties but lacking a thiol group, did not show similar beneficial effects. To better understand the mode of action of captopril in the autoimmune disease we have evaluated its immunomodulatory properties with special emphasis on antigen-specific and polyclonal B- and T-cell activation. The results obtained strongly suggest that Captopril exerts its immunomodulatory effects through stimulation of T-lymphocytes.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1990

Long-term effects of felodipine on blood pressure and renal hemodynamics in severe hypertension.

Felodipine, a dihydropyridine calcium antagonist, was used to treat eight patients with severe uncontrolled hypertension: five had essential hypertension, two had renovascular disease, and one chronic pyelonephritis. Mean blood pressure (BP) was 221 +/- 14/120 +/- 4 mm Hg despite treatment with three or more antihypertensive drugs. All patients experienced an immediate and pronounced lowering of BP after adding felodipine, which persisted during long-term treatment in combination with previous medication except for vasodilating drugs. In all cases, an increase in glomerular filtration rate (51Cr-EDTA clearance) after 6 and 12 months of felodipine treatment was seen (59 +/- 10 to 63 +/- 7 and 70 +/- 6 ml/min, respectively, p less than 0.05). Renal plasma flow (PAH clearance) exhibited only a slight increase (315 +/- 68 to 340 +/- 63 and 314 +/- 69 ml/min), giving a nonsignificant rise in filtration fraction (18 +/- 1 to 21 +/- 1 and 20 +/- 1%, respectively). It is concluded that felodipine decreases BP dramatically in patients with previously refractory hypertension and that the drug causes an improved renal function in these patients.

Adult↗
PubMed1990

Erythrocyte sodium transport in malignant hypertension.

Twenty-three patients with treated malignant hypertension (MH), 23 patients with treated non-malignant hypertension (NMH) and 46 normotensive control subjects were investigated with regard to intraerythrocyte sodium (Na) and potassium (K) levels, as well as transmembrane fluxes of sodium (Na-influx and Na-efflux rate constant). Intraerythrocyte Na and K concentrations were determined by flame photometry. The Na-influx and Na-efflux rate constant were calculated from uptake values for 22Na in vitro. In NMH the Na-influx and Na-efflux rate constant were significantly higher while intraerythrocyte Na and K levels did not differ from the controls. Patients with MH tended to have an elevated intraerythrocyte Na concentration, but an unchanged Na-influx and Na-efflux rate constant relative to controls. The increased rate of erythrocyte membrane transport of Na in treated NMH could be due to a stimulatory effect of antihypertensive treatment on cellular Na transport. Patients with treated MH do not show this effect, and in addition, tend to have an elevated intraerythrocyte Na concentration, which is compatible with the existence of a more pronounced abnormality of cellular ion transport in MH.

Biological Transport↗
PubMed1990

Plasma noradrenaline and dopamine in renin-mediated hypertension.

Noradrenaline (NA) and dopamine (DA) have opposite effects on the kidney; NA causes vasoconstriction and increased sodium reabsorption while DA promotes vasodilation and natriuresis. In 15 patients investigated for renin-mediated hypertension measurements of plasma renin activity (PRA), NA and DA concentrations were made in arterial and renal venous blood from both kidneys before and after acute stimulation of renin release by i.v. dihydralazine. Nine patients had unilateral renin secretion and were classified as renin-positive, while the remaining six patients were renin-negative. Renin-positive patients had higher arterial and renal venous PRA, NA and DA levels than the negative ones. In the renin-positive group V-A differences for NA and DA were present on both sides despite unilateral secretion of renin. NA but not DA levels were higher in the renin-secreting kidney, which can partly be explained by the reduced plasma flow to the involved kidney. After dihydralazine the arterial NA and DA rose similarly in renin-positive and renin-negative patients, while PRA rose only in the renin-positive cases. In the renin-positive patients where stimulation of renin secretion caused a marked increase of the PRA gradient on the affected side only, renal gradients for NA and DA increased bilaterally. The increase in DA was more pronounced than that of NA yielding a rise in DA/NA ratio on the affected side. Arterial PRA was positively correlated to the plasma concentrations of NA and DA. V-A differences for PRA and NA or DA were positively correlated on the involved renin-secreting side. In summary, patients with renin-dependent hypertension have elevated plasma NA and DA concentrations. Stimulation of renin release by dihydralazine increases the DA/NA ratio in arterial and renal venous blood indicating release of 'precursor dopamine' from noradrenergic fibres and/or activation of dopaminergic nerves. There seems to be a relationship between renal nerve activity and renin release in renin-dependent hypertension.

Adolescent↗
PubMed1990

Protective effects of pretreatment with superoxide dismutase, catalase and oxypurinol on tubular damage caused by transient ischaemia.

The effect of 60 min of ischaemia on glomerular and tubular functions (osmolar clearance, fractional Na+ excretion, K+ clearance, concentrating ability) after different periods of time was studied in New Zealand White rabbits. Pronounced changes in both glomerular and tubular functions were observed immediately on reperfusion and after 48 h. One week after ischaemia the functions appeared to be normalized. Mannitol is routinely used in clinical kidney transplantation due to its hyperosmolar effects and its ability to scavenge the hydroxyl radical. In the present study the possible additive protective effect against ischaemia-reperfusion damage of a combined pretreatment with mannitol and oxygen free radical scavengers or mannitol and a xanthine oxidase inhibitor was examined. Oxypurinol was chosen as the xanthine oxidase inhibitor due to its direct inhibitory effect. Concerning glomerular function, no protective effect of the combined pretreatment compared with mannitol alone was observed. However, concerning the tubular function tests combined pretreatment with either mannitol-superoxide dismutase-catalase or mannitol-oxypurinol turned out to be superior compared with that of mannitol alone.

Animals↗
PubMed1990

Effect of acute vascular fluid volume expansion on erythrocyte sodium transport in essential hypertension.

Evidence exists that volume expansion is associated with the appearance of a circulating sodium transport inhibitor. We have evaluated intra-arterial blood pressure (BP), central venous pressure (CVP), plasma renin activity (PRA), intraerythrocyte sodium content, erythrocyte sodium influx and rate constant of sodium efflux in 10 untreated primary hypertensive men (WHO stages I and II). The investigations were done during baseline conditions and after rapid intravenous infusion of 1 litre of saline (0.9% NaCl solution) over 15-20 min. Volume expansion caused an increase in CVP by 6.0 +/- 0.5 cmH2O (p less than 0.01), while BP only exhibited a slight increase. No significant changes in intraerythrocyte sodium content, sodium influx, sodium efflux rate constant or PRA were found after volume expansion compared to baseline. All patients with low normal PRA experienced a decrease in sodium efflux rate constant after volume expansion. We found a positive correlation between baseline PRA and change in sodium efflux rate constant after volume expansion (r = 0.62, p less than 0.05). At baseline the relationship between PRA and intraerythrocyte sodium content nearly reached statistical significance (r = 0.63, p = 0.054). These results may indicate that acute volume expansion influences the release of a circulating factor, modulating sodium transport in low-renin hypertension.

Adult↗
PubMed1990

ACE-inhibitors and quality of life.

A review of the literature concerning quality of life aspects on ACE-inhibitors in hypertensive patients is given. In the first part of the eighties two prospective multi-center randomised trials were conducted to determine the effect of captopril in comparison to methyldopa or an unselective beta-blocker on the quality of life in patients with mild to moderate hypertension (Hill et al. and Croog et al.). Both studies revealed slight but significant positive effects on indices of quality of life in captopril treated patients compared to those who had methyldopa or an unselective beta-blocker. Later, another ACE-inhibitor, enalapril, has been compared with a selective beta-blocker (Edmonds et al. and Herrick et al.) with respect to side-effects and the quality of life. The measurements of the quality of life tended to favour enalapril, but the differences were small and the over-all tolerability of the two drugs was similar. In conclusion, comparisons with more long standing forms of antihypertensive therapy suggest a slightly more favourable effect of ACE-inhibitors on the quality of life.

Adult↗
PubMed1990

Renal sensitivity to angiotensin II in type 1 diabetes.

The role of the renin angiotensin system for the regulation of kidney function in diabetes mellitus is uncertain. Results from studies in diabetic animals suggest that a reduced activity in this system contributes to the renal hyperperfusion and hyperfiltration in diabetes. The renal sensitivity to angiotensin II in diabetic patients is also unknown. Changes in renal hemodynamics were measured after infusion of two low doses of angiotensin II in ten young type 1 diabetic patients without complications and in ten healthy controls. The renin and angiotensin II levels were found to be the same in both groups. The baseline glomerular filtration rate was higher in the diabetics. During the highest angiotensin II dose, the 51Cr-EDTA and PAH clearance decreased 14 +/- 15 and 157 +/- 118 ml/min in the diabetics and 14 +/- 15 and 146 +/- 109 in the controls respectively. The changes in blood pressure and renal vascular resistance or sodium excretion did not differ between the groups. A malfunction of the renin angiotensin system is thus unlikely as a cause of the glomerular hyperfiltration in type 1 diabetes.

Adult↗
PubMed1989

Pharmacokinetics of felodipine in patients with impaired renal function.

1. The pharmacokinetics of felodipine and its effects on blood pressure and heart rate were studied in eight male patients aged between 28 and 57 years with a glomerular filtration rate, GFR, between 8 and 68 ml min-1, following single i.v. and oral administration. 2. Clearance, Cmax, AUC, Vss and V, of felodipine were unaffected by the renal disease. The metabolite excretion (14C-labelled) was slower than in healthy subjects. Initial renal clearance of these metabolites correlated with individual GFR values. The total amount of the dose excreted in the urine was also decreased.

Administration, Oral↗
PubMed1989

Increased secretion of immunoglobulins in malignant hypertension.

Recent evidence suggests that immunogenic factors may be of importance for development and maintenance of severe hypertension. Twenty-three patients with a previously malignant phase of hypertension (MH) were investigated with respect to serum levels as well as actual production of immunoglobulins (lgs) and compared with a group of 22 patients with non-malignant hypertension (NMH) and 45 matched normotensive control subjects (C). Patients with MH had a significantly elevated secretion of IgG and IgA as compared with C. Total serum concentration of lgs did not differ between the groups, but a raised level of the subclass IgG3 was found in MH. There was a significant positive correlation between systolic blood pressure (SBP) and secretion of IgA and IgG when all hypertensive patients were studied. Six patients were subjected to repeated investigations during the first year after malignant phase. If examined in an early phase of MH (within 4 months) the secretion of IgG, IgA and IgM was enhanced compared with later stages (after 5-12 months). The results suggest that an immunological process is involved in MH. This could either be a primary immunological disturbance or more plausibly secondary effects due to the vascular damage caused by the very high blood pressure.

Antihypertensive Agents↗
PubMed1988

Different patterns of cellular sodium turnover in essential hypertension.

Erythrocyte sodium turnover was studied in 22 men aged 56 years who had been treated for hypertension for 7 years. Investigations were performed during treatment, and 1 and 4 weeks after withdrawal of therapy, and when hypertension had returned (blood pressure greater than or equal to 170/105 mmHg). Hypertension returned early in 11 patients (group A) and late in 11 patients (group B). There was no difference in blood pressure, therapy, body weight or peripheral resistance between the groups, but group A had a greater left ventricular mass. Intra-erythrocyte sodium was determined by flame photometry. Sodium influx and the rate constant of sodium efflux were calculated from uptake values of 22Na. In group B the return of hypertension was accompanied by a tendency for an increase in intra-erythrocyte sodium and a decrease in sodium efflux. In group A opposing changes were seen, so that significant differences occurred in sodium efflux and intra-erythrocyte sodium between the groups occurred at the reappearance of hypertension. The results are compatible with the appearance of a membrane abnormality in patients with a slow return of hypertension, whereas other mechanisms, e.g. increased sympathetic activity, may be associated with the more rapid rise in blood pressure in the other group.

Antihypertensive Agents↗
PubMed1988

Effect of captopril on murine systemic lupus erythematosus disease.

The MRL/1 and New Zealand black-New Zealand white cross (NZB x W) mice spontaneously develop a disease similar to systemic lupus erythematosus in man. The effect of antihypertensive treatment on MRL/1 and NZB x W mice was studied with respect to survival, blood pressure, proteinuria, haematuria and renal histopathology. The treatment consisted of angiotensin converting enzyme (ACE) inhibitors (captopril and enalapril) and bretylium, a sympathetic blocker. Tail systolic blood pressure was measured with a strain gauge technique. All antihypertensive drugs caused a reduction in blood pressure in both strains. In MRL/1 bretylium and both ACE inhibitors improved renal histopathology, but only captopril prolonged survival, and it decreased proteinuria and haematuria. In NZB x W captopril decreased proteinuria but did not influence survival or renal histopathology. Bretylium was without any effect on these parameters. At the doses used captopril improves survival in MRL/1 mice and decreases proteinuria and haematuria in both MRL/1 and NZB x W mice. Since bretylium and enalapril lack this property despite a similar blood pressure reduction, it seems to be a drug-specific action.

Animals↗
PubMed1988

Beneficial effect of captopril on systemic lupus erythematosus-like disease in MRL lpr/lpr mice.

MRL lpr/lpr (MRL/l) mice exhibit a disease similar to systemic lupus erythematosus (SLE) in humans. To investigate the influence of antihypertensive treatment on this disease, four groups of MRL/l mice were treated with the angiotensin-converting enzyme inhibitor captopril (n = 25), with the sympathetic blocker bretylium (n = 15), and with cyclophosphamide (n = 10). Thirty-five mice did not receive any treatment and served as controls. Survival rate, blood pressure, incidence of proteinuria and hematuria, renal pathology, lymphoid hyperplasia and dermatitis were studied. The survival at the age of 36 weeks was significantly improved by captopril as compared to controls (60 vs. 25%, p = 0.035). The cyclophosphamide group showed no mortality at that time and the bretylium group did not differ from the control group. Captopril and bretylium reduced systolic blood pressure significantly while cyclophosphamide was without effect. Captopril and cyclophosphamide diminished significantly the glomerular damage with less proliferative changes and a decreased incidence of proteinuria. The bretylium-treated animals also exhibited an improved renal pathology index but they did not differ from the controls with respect to proteinuria and hematuria. Lymphoid hyperplasia and dermatitis were decreased only by captopril and cyclophosphamide. It is concluded that captopril improves survival in SLE disease of MRL/l mice, counteracting lymphoid hyperplasia, renal disease, dermatitis and decreasing arterial blood pressure.

Animals↗
PubMed1988

Effects of sodium restriction and energy reduction on erythrocyte sodium transport in obese hypertensive men.

Twelve moderately obese middle-aged male out-patients with untreated mild hypertension reduced their sodium intake by about 120 mmol/day during 4-6 weeks. The low sodium diet period was followed by a period of energy reduction as well as sodium restriction for 15 weeks. Mean body mass was then reduced by 7.5 +/- 1.0 kg. Intraerythrocyte sodium (IeNa), sodium influx (Na-influx) and sodium efflux rate constant (Na-efflux rate), were measured before intervention, during salt restriction and during salt and energy restriction. Plasma renin activity (PRA) and urinary excretion of aldosterone (U-Aldo) and noradrenaline (U-NA) were also determined during the three observation periods. During sodium restriction there was a significant increase in PRA and U-Aldo, but no change was seen in IeNa, Na-influx or Na-efflux rate constant. During sodium restriction there was a significant positive correlation between PRA and both Na-influx and Na-efflux rate constant. When energy reduction was combined with sodium restriction, PRA and U-NA both diminished significantly. Na-influx and Na-efflux rate also exhibited a significant decrease while IeNa did not change. Sodium restriction caused a significant fall in mean arterial blood pressure and a tendency to a further decrease was seen when energy intake was also reduced. No significant correlation could be found between the fall in blood pressure and changes in cellular sodium transport. These data indicate that the renin-angiotensin-aldosterone system and sympathetic activity influence the regulation of erythrocyte sodium turnover during sodium and energy restriction in obese hypertensive men.

Biological Transport↗
PubMed1987

Pharmacokinetics and pharmacodynamics of ramipril in renal failure.

The pharmacokinetics and pharmacodynamics of the novel angiotensin converting enzyme (ACE) inhibitor ramipril were studied in 6 patients with a glomerular filtration rate of less than 20 ml/min/1.73 m2 of body surface area. A single oral dose of 5 mg was given and serum concentrations of the compound and its diacid, the active metabolite (ramiprilat), as well as ACE activity, blood pressure and pulse rate were monitored for 28 days. The original compound reached peak serum concentrations of 42.8 +/- 26.5 ng/ml about 1 hour after dosing and was completely eliminated from the serum after 24 hours. Ramiprilat reached peak values of 14.4 +/- 11.6 ng/ml after about 6 hours. In contrast with the parent compound, low concentrations of ramiprilat were still detected in the serum after 28 days. ACE activity decreased to approximately 5% of baseline values, remained low for the next 48 hours, then increased slowly thereafter but reached only 84.5% of initial values after 28 days. Blood pressure decreased significantly and remained low for 24 hours after dosing. The drug was well tolerated in all patients. It is concluded that a single 5 mg dose of ramipril was effective in inhibiting plasma ACE activity and lowering blood pressure in patients with renal failure. There was a slower decline in ramiprilat concentrations compared with subjects with normal renal function.

Adult↗
PubMed1987

Clinical evaluation of felodipine in patients with refractory hypertension.

The calcium antagonist, felodipine, was used to treat 21 patients with severe uncontrolled hypertension: 13 had renoparenchymatous hypertension, 5 essential hypertension and 3 renovascular hypertension. Mean arterial blood pressure of patients was 195 +/- 8/122 +/- 3mm Hg in spite of treatment with 3 or more antihypertensive drugs. The majority of the patients (n = 17) were treated with an ACE inhibitor. Mean glomerular filtration rate (GFR) for 20 patients was 39 +/- 6 ml/min/1.73m2 body surface area (Cr-EDTA clearance) before felodipine administration. All patients had an immediate blood pressure fall after 5-10mg of felodipine administered orally. This fall persisted when the drug was given 2 or 3 times daily in combination with previous medication except the former vasodilating drugs. 15 patients are on long term treatment with felodipine and their blood pressure after 1 year (n = 14) was 152 +/- 4/89 +/- 2mm Hg. Patients with moderately impaired renal function and no signs of progressive kidney disease (n = 8) improved their GFR significantly after 1 year on felodipine. Six patients stopped felodipine therapy within 3 months (4 because of adverse reactions, 1 died of scleroderma and 1 became normotensive after the start of dialysis treatment). In patients with renoparenchymatous disease and documented progressive deterioration of renal function the addition of felodipine did not prevent a decline in filtration rate but did slow the rate of deterioration (from 9 +/- 2 to 5 +/- 1 ml/min/year).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗