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Biomedical subjects

R Düsing

Publications and source records attributed to R Düsing.

At least 37 records · Page 2Linked to original sources
PubMed2002

[Therapy resistant hypertension--significance of electronic compliance monitoring].

HISTORY AND CLINICAL FINDINGS: A 71-year-old woman was admitted with arterial hypertension resistant to drug therapy (office readings 197/82 mmHg) under medication with beta-blocker, AT 1 -antagonist and a diuretic. The only physical pathologic finding was an adipositas. DIAGNOSIS, TREATMENT AND COURSE: The patient was suffering from isolated systolic hypertension, grade 3 corresponding to WHO-guidelines. Despite antihypertensive triple therapy office as well as self-measured blood pressure values (mean 170/82 mmHg) remained elevated. Thus, the patient fulfilled the criteria of a resistant hypertension. The degree of compliance was only 50 %, detected by using a Medication-Event-Monitoring-System (correct dosing interval 17.1 %). We discussed the results of compliance- and blood pressure self-measurement with the patient. In the following period of compliance- and blood pressure self-measurement (with unchanged antihypertensive therapy) the compliance increased dramatically with a degree of 90,9 % and self-measured blood pressure values almost normalized (mean 137/71 mmHg). CONCLUSION: The control of compliance by using electronic compliance-monitoring may help to discover non-compliance as a frequent cause of resistant hypertension and to avoid unnecessary cost-extensive procedures.

Aged↗
PubMed2002

The role of losartan in cost-effective hypertension control.

Despite recent guidelines emphasising the need for aggressive treatment in patients with elevated blood pressure, the control of hypertension in Europe and the USA is poor, imposing a considerable burden in terms of patient morbidity and mortality, and associated healthcare costs. A major factor contributing to the suboptimal control of hypertension is the failure of patients to adhere to their prescribed therapy. Drug side-effects are an important cause of non-compliance and prescribing a well-tolerated agent that promotes good compliance is therefore the key to the cost-effective management of hypertension. Several studies have demonstrated that patients are more likely to remain on therapy with the angiotensin II antagonist losartan than other antihypertensives. Although the acquisition costs of new antihypertensives such as losartan are greater than for older drugs, such costs represent only a small proportion of the total cost of prescribing antihypertensive therapy. When accessory costs are also considered, the total cost of care with newer antihypertensives is comparable with those for diuretics. The costs involved if therapy has to be switched due to unacceptable side-effects also need to be taken into account when assessing relative cost effectiveness. Furthermore, savings may accrue from the non-haemodynamic benefits of losartan, such as improved cognitive function and renal protection. Further studies will increase awareness of the true cost effectiveness of antihypertensive drugs.

Antihypertensive Agents↗
PubMed2001

The fibrinolytic system in chronic renal failure.

BACKGROUND: Patients with chronic renal failure (CRF) face a high risk of cardiovascular morbidity and mortality. Impaired fibrinolysis has recently been acknowledged to function as a risk factor for cardiovascular ischemic complications. Whether changes in fibrinolytic function contribute to the increased cardiovascular risk in CRF, however, remains unclear. METHODS: In the present study, tissue-plasminogen activator (t-PA) and its main antagonist plasminogen activator inhibitor-1 (PAI- 1) were determined in 12 subjects with normal renal function (group A) [serum creatinine (Cr) <1.3 mg/dl], 24 patients with impaired renal function (Cr 1.3-6.5 mg/dl) (group B) and 22 patients with endstage renal disease (ESRD) on hemodialysis (Cr>6.5 mg/dl) (group C). RESULTS: Plasma concentrations of PAI-1 and t-PA antigen as well as the PAI-1:t-PA molar ratio were unchanged in group B as compared to group A. However, in ESRD patients (group C), t-PA concentrations markedly decreased [13.7 +/- 2.9 ng/ml vs. 32.8 +/- 4.7 ng/ml (group B, p <0.01) and 35.4 +/- 8.4 ng/ml (group A, p <0.01)] while PAI-1 antigen concentrations remained in the control range. Thus, the PAI-1:t-PA molar ratio significantly increased in group C patients [12.4 +/- 4. 0 vs. 6.0 +/- 2.5 (group B; p<0.01) and 4.5 +/- 1.7 (group A; p<0.01]. CONCLUSIONS: From our data it may be suggested that fibrinolysis is markedly disturbed in ESRD due to a decreased availability of t-PA. Thus, it may be speculated that the development of atherothrombotic events in hemodialysis patients is, at least in part, due to an impaired fibrinolysis.

Adult↗
PubMed2001

[Change from ACE inhibitor, Ca-antagonist or beta-blocker to candesartan cilexetil: better efficacy and tolerance. SWITCH study (German study segment)].

BACKGROUND AND OBJECTIVE: Lack of efficacy in the treatment of hypertension with only one drug presents a problem in general practice and often requires switching to another type of drug, because higher dosage of currently used antihypertensives increases the frequency of side effects. Angiotensin II antagonists are well tolerated and there is no evidence of dose-related increase in side effects. This study in 574 hypertensives under therapy with ACE inhibitors, beta-blockers or calcium channel blockers was undertaken to determine whether direct switching to the Angiotensin II-antagonist candesartan cilexetil at its maximal dose of 16 mg is as effective and tolerable as starting therapy with candesartan cilexetil 8 mg followed by up-titration to 16 mg after 4 weeks. PATIENTS AND METHODS: 258 men (mean age 57 +/- 11 years) and 316 women (58 +/- 12) with essential hypertension (blood pressure < 180/95 mm Hg) under ambulatory therapy with ACE-inhibitors, beta-blockers or calcium channel blockers with inadequate efficacy or tolerability were switched to monotherapy with candesartan cilexetil. Half of the patients were treated with 8 mg for 4 weeks (n = 284), the other half received 16 mg (n = 290). Both groups then were treated with candesartan cilexetil, 16 mg, for further 4 weeks. Choice of treatment was doubly blinded and randomised. RESULTS: After 4 weeks significant blood pressure reduction was observed in both treatment groups (p < 0.0001 for each pretreatment group). A tendency for more adequate blood pressure reduction under initial therapy with candesartan cilexetil 16 mg was observed. There was a small further blood pressure reduction in both treatment groups after 8 weeks. In comparison with the previous medications the proportion of patients with blood pressure reduction < 90 mm Hg diastolic was doubled in both treatment arms after 4 weeks: after initial dose of candesartan cilexetil 8 mg from 36.7% to 78.8%, after initial dose of candesartan cilexetil 16 mg from 43.9% to 81.1%. Clinically relevant side effects were not observed. CONCLUSION: Switching of antihypertensive monotherapy with ACE inhibitors, beta-blockers or calcium channel blockers to candesartan cilexetil 8 mg or 16 mg under ambulatory conditions is safe and equally well tolerated and effectively reduces blood pressure.

Adolescent↗
PubMed2001

Angiotensin II-induced stimulation of p21-activated kinase and c-Jun NH2-terminal kinase is mediated by Rac1 and Nck.

p21-activated kinase (PAK) has been shown to be an upstream mediator of JNK in angiotensin II (AngII) signaling. Little is known regarding other signaling molecules involved in activation of PAK and JNK by AngII. Rho family GTPases Rac and Cdc42 have been shown to enhance PAK activity by binding to p21-binding domain of PAK (PAK-PBD). In vascular smooth muscle cells (VSMC) AngII stimulated Rac1 binding to GST-PAK-PBD fusion protein. Pretreatment of VSMC by genistein inhibited AngII-induced Rac1 activation, whereas Src inhibitor PP1 had no effect. Inhibition of protein kinase C by phorbol 12,13-dibutyrate pretreatment also decreased AngII-mediated activation of Rac1. The adaptor molecule Nck has been shown previously to mediate PAK activation by facilitating translocation of PAK to the plasma membrane. In VSMC AngII stimulated translocation of Nck and PAK to the membrane fraction. Overexpression of dominant-negative Nck in Chinese hamster ovary (CHO) cells, stably expressing the AngII type I receptor (CHO-AT1), inhibited both PAK and JNK activation by AngII, whereas it did not affect ERK1/2. Finally, dominant-negative Nck inhibited AngII-induced DNA synthesis in CHO-AT1 cells. Our data provide evidence for Rac1 and Nck as upstream mediators of PAK and JNK in AngII signaling and implicate JNK in AngII-induced growth responses.

Adaptor Proteins, Signal Transducing↗
PubMed2001

The plasminogen activator inhibitor 1 4G/5G polymorphism is not associated with longevity: a study in octogenarians.

Accumulating evidence suggests that plasma levels of the plasminogen activator inhibitor 1 (PAI-1) may modulate the risk of coronary artery disease. The regulation of PAI-1 levels underlies not only environmental but also genetic influences. The 4G/5G polymorphism of the PAI-1 gene has recently gained additional relevance as a possible cardiovascular risk factor, as the 4G allele may be associated with enhanced expression of the PAI-1 gene. This retrospective cohort study examined the effect of the PAI-1 4G/5G genotype on longevity among 205 subjects aged 80 years and older. Such studies in larger cohorts have recently become available along with new methods for the rapid and easy determination of gene polymorphisms. We utilized a light-cycler assisted method which is a fast and flexible method of analyzing the PAI-1 4G/5G polymorphism on the gene level. In these 205 persons the 4G/5G allele was found in 96 persons (47%), the 4G/4G variant in 62 (30%), and the 5G/5G allele in 47 (23%). These data are similar to the allele distribution described in other large cohorts not restricted to old age. Thus the results of this study are not suggestive of an important contribution of the PAI-1 genotype on total mortality.

Aged↗
PubMed2001

Adverse events, compliance, and changes in therapy.

Compliance with medical therapy represents a multifactorial problem with marked consequences for individual and public health. Among the many contributing factors, the choice of drug may also determine the degree of compliance. Various studies investigating either compliance or persistence with antihypertensive therapy using a variety of methods have suggested that adherence to therapy may show the following pattern: diuretics < beta-blockers < calcium channel blockers < ACE inhibitors. Furthermore, two recent studies have shown that therapy with angiotensin II receptor blockers may be associated with better long-term adherence than other antihypertensive monotherapies including angiotensin converting enzyme inhibitors. Since medication compliance with antihypertensive therapy, among other factors, closely correlates with the experience of side effects, it may be speculated that the different classes of antihypertensives may induce varying degrees of compliance and persistence due to their different tolerability profiles. Side effects may induce variable compliance and nonpersistence by yet another mechanism. Therapy turbulence, ie, any change in medication, is also associated with nonpersistence. Therefore, side effects may directly or indirectly (via inducing therapy turbulence) underly variable compliance and nonpersistence.

Antihypertensive Agents↗
PubMed2000

[Renin-angiotensin-aldosterone system and fibrinolysis].

Experimental, genetic and clinical evidence suggests that the renin-angiotensin-aldosterone system (RAAS) may participate in the pathogenesis of thromboembolic cardiovascular disorders such as coronary heart disease. This interrelationship may involve mechanisms other than changes in arterial blood pressure. In addition to various possible interactions, accumulating evidence suggests that the RAAS is involved in the regulation of the fibrinolytic system. Several recent studies have shown that stimulation of the RAAS may be associated with an activation of plasminogen activator inhibitor 1 (PAI-1). Since profibrinolytic factors (especially tissue plasminogen activator [t-PA]) remain unchanged, increased activity of the RAAS may thus alter the fibrinolytic balance towards a decreased fibrinolytic activity. These findings may be of special importance for a variety of clinical problems such as the long-term effect of a low NaCl-intake on cardiovascular morbidity and mortality and the possible value of drugs indirectly or directly interfering with the RAAS such as diuretics, ACE-inhibitors and angiotensin II Type 1 (AT1) receptor antagonists.

Aldosterone↗
PubMed2000

Effects of valproate derivatives I. Antiepileptic efficacy of amides, structural analogs and esters.

Derivatives of the antiepileptic drug valproate (VPA, 2-propylpentanoic acid) have been synthesized and tested in order to improve the intracellular availability of VPA. The buccal ganglia of Helix pomatia were used as a test nervous system and antiepileptic efficacies were reconfirmed using rat cortex in vivo. Epileptiform activities consisted of typical paroxysmal depolarization shifts (PDS) which appeared in the identified neuron B3 with application of pentylenetetrazol. Epileptiform activities were found to be accelerated, unaffected or blocked. (i) The Amide-derivatives 2-propylpentanamide and N,N-dipropyl-2-propylpentanamide, and short chain ester derivatives 1-O-(2-propylpentanoyl)-2,3-propandiol, 2,2-di(hydroxymethyl)-1-O-(2-propylpentanoyl)-1,3-propanediol and 2,2-di(hydroxymethyl)-1,3-di-O-(2-propylpentanoyl)-1,3-propanediol accelerated epileptiform activities. Membrane potential often shifted to a permanent depolarization which corresponded to the PDS-inactivation level. (ii) The structural analogs 1-cycloheptene-1-carboxylic acid and cyclooctanecarboxylic acid accelerated epileptiform activities only slightly or were without effects. (iii) The small VPA-ester, 2-propylpentanoic acid ethyl ester, decreased the epileptiform activities in a way that is comparable to the effects of VPA well known from previous studies. It thus could be thought as a VPA-pro-drug. (iv) The mannitol-esters 1-O-(2-propylpentanoyl)-D-mannitol and 3,4;5,6-Di-O-isopropylidene-1-O-(2-propylpentanoyl)-D-mannitol blocked the PDS in a way which is different from the known effects of VPA. These substances are interpreted not to exert their effects after being metabolized to VPA and thus they are thought to be new antiepileptic substances.

Amides↗
PubMed2000

Effects of valproate derivatives II. Antiepileptic efficacy in relation to chemical structures of valproate sugar esters.

The structure effect relationships of derivatives of the antiepileptically active ester of valproate (VPA) 3,4:5,6-Di-O-isopropylidene-1-O-(2-propylpentanoyl)-D-mannitol (1) have been studied using intracellular recording to record the membrane potential of single neurons (buccal ganglia, Helix pomatia). Epileptiform activity was induced by the epileptogenic drug pentylenetetrazol. The effects of several derivatives on epileptiform activity were compared with those of the relay compound 1. Most of the synthesized agents decreased the duration of paroxysmal depolarization shifts (PDS) and increased their repetition rate. It was considered that a decreased the duration of PDS is antiepileptic and an increased repetition rate is pro-epileptic. Compared with the effects of compound 1, the following relationships were found: (1) Derivatives containing glucitol or galactitol were of similar antiepileptic potency. (2) Introduction of pyranoses or furanoses rendered the substances inactive or even pro-epileptic. (3) VPA in position 1 and 6 at the sugar acted as an antiepileptic whereas in position 3 and 4 it proved to be ineffective. (4) Replacement of VPA by ethylhexanoyl reduced the antiepileptic potency slightly and pivaloyl strongly. (5) Replacement of isopropylidene bridges by penta-O-acetyl or cyclohexylidene residues led to largely inactive substances. (6) Compounds having isopropylidene bridges in position 2,4;3,5 proved to be antiepileptic whereas bridges especially in positions 2,3:4,5 slightly enhanced epileptic activities.

Animals↗