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Biomedical subjects

N Bender

Publications and source records attributed to N Bender.

At least 19 recordsLinked to original sources
PubMed2004

Gene therapy: a concept for the future in medical practice? The current state.

Gene therapy is a new therapeutic approach which is tested in numerous diseases connected with either non or only limited therapeutic effects. This paper aims at discussing the actual state of the clinical development of gene-therapy which targets an approval by either the FDA or EMEA. Basis of all the figures and tables presented is a BioMedNet/Medline search reviewing all titles found under the keywords gene therapy and/or clinical development. The review period begins in the year 1992 and ends in 2002. Publications identified were sorted into the following categories: therapeutic areas with gene therapy activities; indications and diseases with gene-therapy activities; vectors used in gene therapy and clinical studies using gene therapy. Only in some indications like breast cancer, colorectal cancer, HIV, and cystic fibrosis a variety of clinical studies had been published indicating a serious attempt to develop the indication for approval. But most developments are still in phase I/II. In all other therapeutic areas no systematic continuous approach was identified. Clinical activities in cardiovascular diseases and in peripheral vascular diseases increased during the preceding five years compared other therapeutic areas.

Clinical Trials as Topic↗
PubMed2001

Improving cognitive development of low-birth-weight premature infants with the COPE program: a pilot study of the benefit of early NICU intervention with mothers.

The purpose of this pilot study was to evaluate the effectiveness of a parent-focused intervention program (COPE) on infant cognitive development and maternal coping. A randomized clinical trial was conducted with 42 mothers of low-birth-weight (LBW) premature infants hospitalized in a neonatal intensive care unit (NICU), with follow-up at 3 months' and 6 months' corrected ages. COPE mothers received the four-phase educational-behavioral program that began 2-4 days postbirth and continued through 1 week following discharge from the NICU. Comparison mothers received audiotaped information during the same four time frames. Results indicated that COPE infants had significantly higher mental development scores at a 3 months' corrected age (M = 100.3) than did the comparison infants (M = 93.9), and this difference widened at 6 months' corrected age, with COPE infants scoring 14 points higher. COPE mothers were significantly less stressed by the NICU sights and sounds and had significantly stronger beliefs about what behaviors and characteristics to expect from their premature infants. Findings from this study support the need for further testing of early NICU interventions with parents to determine their effectiveness on parental coping and infant developmental outcomes.

Adaptation, Psychological↗
PubMed1995

Pharmacokinetics, metabolism and biliary and urinary excretion of oral ramipril in man.

In order to evaluate the pharmacokinetics and excretion of ramipril in man, 8 cholecystectomy patients aged between 53 and 68 years received 5 mg ramipril orally as a single dose. All patients had a T-drain inserted to permit bile collection; all gave their informed consent to participate in the trial. Serum samples were collected half-hourly until 2 hours, then hourly until 6 hours, then at 8, 10, 24 and 25 hours after intake. Urine was collected in 2-hour fractions until 8 hours, followed by a 4- and a 12-hour fraction. Bile was collected hourly until 6 hours, followed by a 6- and a 12-hour collecting fraction. Concentrations of ramipril and ramiprilat in serum, and determinations in urine and bile of ramipril, ramiprilat, ramipril glucuronide, ramiprilat glucuronide, diketopiperazine and diketopiperazine acid were made; total amounts excreted were calculated. Peak concentrations of ramiprilat in plasma (8.7 +/- 1.6 ng/ml) were reached after about 8 hours. AUC0-8 and AUC0-24-values were 36.5 and 111.9 ng.h/ml, respectively. Ramiprilat Cmax-concentrations were about 300-fold higher in bile than in plasma, the corresponding difference for ramipril between bile and plasma was about 4-fold. The main fractions excreted in the urine were diketopiperazine acid and ramiprilat amounting to 13.2 +/- 5.6 and 4.4 +/- 2.4%, respectively, of the dose administered. Only a very small fraction of the dose was excreted with urine as unchanged ramipril, on average 0.9 +/- 1.0%. The main fractions excreted in the bile were diketopiperazine acid, ramiprilat glucuronide and diketopiperazine, 9.0 +/- 5.3, 3.4 +/- 4.2 and 2.0 +/- 1.2% in 24 hours, respectively, of the dose administered. Only a negligible fraction of the dose (average 0.1 +/- 0.1%) was excreted with bile as unchanged ramipril. In conclusion, there is strong evidence that circulating ramipril and ramiprilat are eliminated by both the liver and the kidneys. For the patients studied it can be estimated from late collection periods that some 2/3 of circulating ramipril and ramiprilat are eliminated by the kidneys and 1/3 eliminated by the liver.

Administration, Oral↗
PubMed1994

Inhibition of bradykinin-induced vasodilation in human forearm vasculature by icatibant, a potent B2-receptor antagonist.

1. The effect of icatibant (D-Arg-[Hyp3, Thi5, D-Tic7, Oic8] bradykinin) a potent B2-kinin receptor antagonist, was studied on bradykinin-induced vasodilation in the human forearm. 2. Eight healthy normotensive men were studied in a rising dose random-placebo controlled study. Placebo and icatibant (20, 50 and 100 micrograms kg-1 i.v.) were administered double-blind. Forearm blood flow was measured by venous occlusion plethysmography during rising dose brachial artery infusions of bradykinin (10-3,000 ng min-1) 60-90 min after placebo or icatibant. 3. Plasma concentrations of icatibant fell exponentially following each of three doses, up to the final measurement. Elimination half-lives calculated from linear regression of the mean data were 25, 27 and 29 min after 20, 50 and 100 micrograms kg-1 doses respectively. 4. Icatibant inhibited the effect of bradykinin (P < 0.001 at each dose of icatibant) in a dose-dependent manner. Bradykinin (100 ng min-1) increased mean blood flow in the infused arm by 238 +/- 31% when infused following placebo, by 112 +/- 21% after icatibant 20 micrograms kg-1, by 71 +/- 14% after icatibant 50 micrograms kg-1 and by 48 +/- 9% after icatibant 100 micrograms kg-1. 5. These results demonstrate that icatibant antagonises B2-receptor mediated vasodilation in human forearm resistance vessels. The findings provide a quantitative basis for future studies of the role of bradykinin in the response to angiotensin converting enzyme inhibitors and in circulatory disease.

Adrenergic beta-2 Receptor Antagonists↗
PubMed1993

Combination of ramipril and hydrochlorothiazide in the treatment of mild to moderate hypertension--Part 2: An open long-term study of efficacy and safety.

In an open, multicenter extension of a short-term study, 159 patients with mild to moderate hypertension were treated with either ramipril monotherapy or a combination of ramipril and hydrochlorothiazide for up to 1 year. Patients started with either 5 mg ramipril once daily (responders in the short-term study) or a combination of ramipril 5 mg plus hydrochlorothiazide 25 mg once daily. The dose could be adjusted and nonresponders to ramipril monotherapy could have hydrochlorothiazide added. In the 38 patients treated with ramipril monotherapy, the largest drop in mean blood pressure (BP) had already occurred in the previous short-term study; from Week 2 in the long-term study, the BP remained stable with means below 150/90 mmHg. In the 83 patients treated with the combination for 50 weeks or more, mean BP continued to decrease until around Week 10 in the long-term study while therapy was being adjusted. Thereafter, it also remained stable with means below 150/85 mmHg. Both treatment groups showed good mean reductions at end point, as did the group of 38 patients treated with the combination for less than 50 weeks. High response rates (84-95%) were seen in all groups at end point. The combination was well tolerated and the efficacy of ramipril in combination with hydrochlorothiazide was maintained over the 1-year period of investigation.

Adult↗
PubMed1993

Short report: ramipril and hydrochlorothiazide combination therapy in hypertension: a clinical trial of factorial design. The East Germany Collaborative Trial Group.

OBJECTIVE: To identify appropriate dosages of ramipril and hydrochlorothiazide (HCT) when given in combination once a day for the treatment of essential hypertension. DESIGN: A 2- or 4-week placebo run-in followed by 6-week, double-blind, parallel-group phase: 4 x 3 factorial (2.5, 5 and 10 mg ramipril; 12.5 and 25 mg HCT; all six combinations; placebo). SETTING: Office practice (21 centres). PATIENTS AND PARTICIPANTS: Patients with mild-to-moderate essential hypertension (World Health Organization stage I-II; supine diastolic blood pressure 100-115 mmHg in last 2 weeks of run-in): 581 enrolled, 534 randomly assigned to double-blind therapy and 517 completed. MAIN OUTCOME MEASURES: Reduction in supine and standing blood pressure. RESULTS: In pairwise comparisons, the combinations of 5 mg ramipril with 12.5 and 25 mg HCT and 10 mg ramipril with 12.5 mg HCT consistently produced significantly greater blood pressure reductions than their respective components. Response surface analyses were performed, and a stairstep model was constructed to characterize the shape of the dose-response surface. The combinations involving 5 and 10 mg ramipril with 12.5 and 25 mg HCT were again more effective than their components. Withdrawals and adverse effects were minimal for all treatments. A large drop in serum potassium was observed on 25 mg HCT, but not on combination therapy. Addition of ramipril appeared to reduce the hyperuricaemic effect of HCT. CONCLUSIONS: Several dosage combinations of ramipril plus HCT produced significantly greater blood pressure reductions than the monotherapies at the same dosages. Overall, the combination of 5 mg ramipril and 25 mg HCT gave the best mean reduction. Combination therapy with ramipril plus HCT was safe and effective for patients with mild-to-moderate essential hypertension.

Double-Blind Method↗
PubMed1993

Multiple-dose pharmacokinetics of ramipril in patients with chronic congestive heart failure.

Thirteen patients with chronic congestive heart failure of NYHA class II-III received multiple doses (14 days) of ramipril (5 mg once daily); the concentrations of ramipril and ramiprilat in plasma, as well as ramipril, ramiprilat, glucuronides, diketopiperazine, and diketopiperazine acid in urine were measured at various times for 14 days. One patient dropped out after the first day due to hypotension and another who accidentally received another ACE inhibitor additionally was excluded, so that 11 patients completed the study. Ramipril and ramiprilat in plasma were determined by radioimmunoassay, and ramipril and its metabolites in urine were measured by gas chromatography in the laboratories of Hoechst AG. Peak concentrations of the active substance ramiprilat were reached after about 4 h and amounted to 22.3 +/- 11.1 ng/ml after the first dose, and a peak concentration of 26.6 +/- 10.0 ng/ml was observed 2.5 +/- 1.4 h on average after administration on day 14. Practically no accumulation was observed for ramiprilat; the AUD (0-24 h) values increased from 191.3 +/- 83.1 ng.h/ml for the first study day to 238.3 +/- 98.0 ng.h/ml for day 14. As expected, only very small fractions of the dose were excreted with urine as unchanged ramipril and ramipril glucuronide. Ramiprilat is excreted with urine to a larger extent than is rampiril--on average 6.6 +/- 3.0% on the first day and 12.2 +/- 3.8% on day 14. The total amount excreted increased by 34% on average, and was mainly due to an increased ramiprilat excretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1992

Combination of ramipril and hydrochlorothiazide in the treatment of mild to moderate hypertension: Part 1--A double-blind, comparative, multicenter study in nonresponders to ramipril monotherapy.

In a parallel-group multicenter study, the efficacy and safety of combination therapy with ramipril 5 mg plus hydrochlorothiazide 25 mg were compared double-blind with those of 5 mg and 10 mg ramipril monotherapy in patients with mild to moderate hypertension who had not responded adequately to ramipril 5 mg alone. Patients were initially treated single-blind for 1 week with ramipril 2.5 mg and 3 weeks with ramipril 5 mg. Of 240 patients enrolled, 165 were subsequently classed as nonresponders (diastolic blood pressure > 90 mmHg) and were randomized to one of the three double-blind treatments for a further 4 weeks. In the double-blind phase, the mean reductions in supine systolic and diastolic blood pressures at end point were significantly greater in the 5 mg plus 25 mg combination group (11.6/10.6 mmHg) than in the groups receiving ramipril 5 mg (6.2/5.9 mmHg; both p < 0.01) and ramipril 10 mg (7.4/7.1 mmHg; both p < 0.05). The proportion of responders at end point was also higher for combination therapy (72%) than for monotherapy (48% for ramipril 5 mg and 62% for ramipril 10 mg). All three treatments were well tolerated. Analysis of laboratory values revealed no clinically important changes.

Adult↗
PubMed1990

Physicochemical and enzyme binding kinetic properties of a new angiotensin-converting enzyme inhibitor ramipril and their clinical implications.

After oral administration, ramipril, a nonsulfhydryl angiotensin-converting enzyme (ACE) inhibitor, is transformed in the liver into its active metabolite ramiprilat. Because of its pentane ring it is at least 23 times more lipophilic than enalaprilat. The in vitro affinity for ACE is 7 times higher than for enalaprilat and 47 times higher than for captopril. The ramiprilat-ACE complex is therefore very stable and dissociates 6 times more slowly than the enalaprilat ACE complex and 72 times more slowly than the captopril ACE complex. Consequently, ramipril is pharmacologically more potent and has a longer duration of action than enalapril and captopril. The blood pressure lowering effect of ACE inhibitors is attributed to the decrease in angiotensin II in serum and locally in target organs of hypertension: heart, vessel wall, kidney and brain. Inhibition of tissue renin-angiotensin system by ramipril has been described in target organs of hypertension in animal models and in clinical studies. Possibly due to its high lipophilicity, and strong affinity to the converting enzyme a better tissue penetration and a more pronounced local ACE inhibition in the target organs has been observed, as compared to other ACE inhibitors. In a preliminary investigation a direct action of ramipril on the tissue RAS in hypertensive patients could also be demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1989

The renin-angiotensin system and ramipril, a new converting enzyme inhibitor.

Angiotensin converting enzyme (ACE) inhibitors have offered new perspectives in the treatment of hypertension. The development of new ACE inhibitors such as ramipril provides an opportunity to improve the knowledge on this class of drug, and to optimize the benefit/risk ratio for the patient. Ramipril was selected among several analogs because of its unique physicochemical properties. It is a nonsulfhydryl ACE inhibitor, and after oral absorption it is transformed in the liver into its active metabolite ramiprilat, which is at least 23 times more lipophilic than enalaprilat. Furthermore, the in vitro affinity of ramiprilat for the enzyme is 7 times higher than for enalaprilat and 47 times higher than for captopril. The ramiprilat-ACE complex is therefore very stable and dissociates 6 times more slowly than the enalaprilat-ACE complex and 22 times more slowly than the captopril-ACE complex. Ramipril possesses a favorable pharmacokinetic profile as a consequence of its physicochemical properties: its high potency allows the use of very low doses, and the slow dissociation of the ramipril-ACE complex explains the long duration of its action, permitting a once-daily treatment. Dose-finding studies have confirmed that very low doses of ramipril--2.5 mg once a day--can be used as a first-step treatment of hypertension. This dose can be increased up to 5 mg, and if necessary a low dose of a diuretic can be added. Using this therapeutic scheme, ramipril normalized blood pressure, insuring that each patient receives the smallest effective dose. Inhibition of the tissue renin-angiotensin system by ramipril has been described in recent studies on animal models.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1988

Evaluation of the biological effects of low-molecular-weight heparins.

In experiments with a laser thrombosis model in rat mesenteric venules, where laser beams induce defined injuries at the vessel endothelium, antithrombotic potency of low-molecular-weight (LMW) heparins was calculated by the number of laser injuries required to induce vessel occluding thrombi. The antithrombotic effect of various LMW heparins was measured at defined time intervals after subcutaneous application. Simultaneously, rat blood was collected and aXa and aIIa plasma levels were determined by chromogenic substrate assays. The antithrombotic effect calculated in the animal model lasted longer than 48 h after a single subcutaneous heparin injection whereas the anticoagulative effect measured as aXa or aIIa activity was measurable only within the first 6 h after subcutaneous application. LMW heparins showed an antithrombotic effect at dosages where no influence on the coagulation system could be demonstrated.

Animals↗
PubMed1976

The selective blocking of the polymerization reaction of striated muscle actin leading to a derivative suitable for crystallization. Modification of Tyr-53 by 5-diazonium-(1H)tetrazole.

The polymerization reaction of rabbit muscle actin was completely inhibited by reaction of one amino acid side chain per protein monomer with 5-diazonium-(1H)[14C]tetrazole. A tryptic peptide fingerprint showed a single peptide labeled by the reagent. The peptide was isolated and the labeled amino acid identified by amino acid analysis as Tyr-53. This side chain is not accessible to the reagent in F-actin. The modification is compared to similar inhibitions by other reagents.

Actins↗