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Biomedical subjects

Michael Wolzt

Publications and source records attributed to Michael Wolzt.

At least 55 records · Page 3Linked to original sources

Circulating plasma levels of vascular endothelial growth factor in patients with sleep disordered breathing.

INTRODUCTION: Cellular vascular endothelial growth factor (VEGF) expression is increased in response to regional hypoxia, however, contradictory results were reported on the effects of systemic hypoxemia on circulating VEGF levels. This study investigated plasma concentrations of VEGF in patients with a variable degree of overnight hypoxemia due to sleep disordered breathing (SDB). METHODS: VEGF levels were assessed by ELISA in non-activated (VEGFbl) and thrombin stimulated platelet rich plasma (VEGFprp) of 45 patients with SDB: Group 1 patients with obstructive sleep apnea and an apnea-hypopnea index (AHI) > 15/h; Group 2 subjects with an AHI < 5/h; Group 3 patients on CPAP treatment for sleep apnea. RESULTS: 39 patients were included in the final analysis. Patients in Group 1 had a higher %time of sleep with SaO2 <90% and a significantly lower mean and minimum overnight oxygen saturation than subjects in Group 2 and patients in Group 3 (P<0.05). Despite significant differences in overnight oxygenation, VEGFbl and VEGFprp concentrations were not significantly different between the three study groups. However, plasma levels of VEGFbl were significantly higher (P = 0.02) in SDB patients with arterial hypertension (n = 19; VEGFbl: 14.0+/-3.3 pg/ml) than in those without arterial hypertension (n = 20; VEGFbl: 10.9+/-5.2 pg/ml). There were no relationships between VEGF levels and polysomnographic oxygenation parameters. In univariate analysis we observed significant relationships for VEGFbl with BMI (C: 0.393; P<0.05) and serum fibrinogen (C: 0.399; P<0.05). CONCLUSIONS: Circulating plasma VEGF levels in patients with sleep disordered breathing may be unrelated to night time hypoxemia (257 Words).

Adult↗

The inhibitory effect of melagatran, the active form of the oral direct thrombin inhibitor ximelagatran, compared with enoxaparin and r-hirudin on ex vivo thrombin generation in human plasma.

INTRODUCTION: The effect of the oral direct thrombin inhibitor (DTI) ximelagatran (Exanta, AstraZeneca) on the endogenous thrombin potential (ETP) of activated plasma was investigated ex vivo using a thrombin generation assay and compared with recombinant (r)-hirudin and enoxaparin. MATERIALS AND METHODS: 120 healthy male volunteers were randomized to one of six treatment groups (n=20 in each): oral ximelagatran (15, 30, or 60 mg), intravenous r-hirudin (0.4 mg/kg bolus, 0.15 mg/kg/h infusion for 2 h, followed by 0.075 mg/kg/h infusion for 2 h), subcutaneous enoxaparin (100 IU/kg), or control (tap water administered orally). Venous blood was collected predose and at 2, 4, and 10 h postdosing. Thrombin generation was triggered by the addition of tissue factor to platelet-poor plasma, and the ETP and time to peak thrombin generation were measured. RESULTS AND CONCLUSIONS: A significant and dose-dependent reduction in ETP was observed 2 and 4 h after the administration of ximelagatran 30 mg (70.3% of predose, 95% confidence intervals 63.0-78.5, P<0.0001 at 2 h) and 60 mg (49.8%, 43.2-57.4, P<0.0001 at 2 h), r-hirudin (19.5%, 10.1-37.6, P<0.0001 at 2 h), and enoxaparin (34.2%, 21.4-54.7, P<0.0001 at 2 h). Ximelagatran (30 mg, 3.79 min, 3.52-4.08 at 2 h), r-hirudin (6.23 min, 4.93-7.86 at 2 h), and enoxaparin (4.68 min, 3.30-6.64 at 2 h) also delayed the lag phase before the thrombin generation burst compared to placebo (2.92 min, 2.71-3.25 at 2 h). The oral DTI ximelagatran, in its active form melagatran, is a potent thrombin inhibitor that efficiently decreases ETP and delays the generation of thrombin in plasma in this ex vivo model.

Administration, Oral↗

Acute Escherichia coli endotoxaemia decreases the plasma l-arginine/asymmetrical dimethylarginine ratio in humans.

Acute inflammation impairs vascular function. Based on the association between endothelial dysfunction and plasma concentrations of L-arginine and the endogenous nitric oxide synthase inhibitor ADMA (asymmetrical dimethylarginine), we hypothesized that the ratio between L-arginine and ADMA could be affected by experimental inflammation. Plasma concentrations of L-arginine, ADMA and SDMA (symmetrical dimethylarginine) were studied at baseline and 3.5 h after intravenous administration of Escherichia coli endotoxin [LPS (lipopolysaccharide), 20 units/kg of body mass; n =8] or placebo ( n =9) in healthy males. L-Arginine and dimethylarginines were quantified after solid-phase extraction by reversed-phase HPLC. Body temperature, heart rate and leucocyte count increased after LPS administration ( P <0.01 for all). LPS administration decreased plasma concentrations of L-arginine from 66 micromol/l [95% CI (confidence interval): 56, 88] at baseline to 48 micromol/l (CI: 40, 60) after 3.5 h ( P <0.02), but did not affect ADMA and SDMA concentrations. Consequently, the L-arginine/ADMA ratio declined significantly from a median of 159 (CI: 137, 193) to 135 (CI: 103, 146); a decrease of 25 (CI: -68, -13; P <0.02). L-Arginine, ADMA, SDMA and the L-arginine/ADMA ratio remained constant over time in controls. Acute inflammation reduces the L-arginine/ADMA ratio which could contribute to impaired vascular function.

Acute Disease↗

First human chronic experience with cardiac contractility modulation by nonexcitatory electrical currents for treating systolic heart failure: mid-term safety and efficacy results from a multicenter study.

INTRODUCTION: Conventional electrical therapies for heart failure (HF) encompass defibrillation and ventricular resynchronization for patients at high risk for lethal arrhythmias and/or with inhomogeneous ventricular contraction. Cardiac contractility modulation (CCM) by means of nonexcitatory electrical currents delivered during the action potential plateau has been shown to acutely enhance systolic function in humans with HF. The aim of this multicenter study was to assess the chronic safety and preliminary efficacy of an implantable device delivering this novel form of electrical therapy. METHODS AND RESULTS: Thirteen patients with drug-resistant HF (New York Heart Association [NYHA] class III) were consecutively implanted with a device (OPTIMIZER II) delivering CCM biphasic square-wave pulses (20 ms, 5.8-7.7 V, 30 ms after detection of local activation) through two right ventricular leads screwed into the right aspect of the interventricular septum. CCM signals were delivered 3 hours daily over 8 weeks (3-hour phase) and 7 hours daily over the next 24 weeks (7-hour phase). Safety and feasibility of this novel therapy were regarded as primary endpoints. Preliminary clinical efficacy, -as expressed by changes in ejection fraction (EF), NYHA class, 6-minute walking test (6-MWT), peak O(2) uptake (peak VO(2)), and Minnesota Living with HF Questionnaire (MLWHFQ), was assessed at baseline and at the end of each phase. At the end of follow-up (8.8 +/- 0.2 months), all patients were alive, without heart transplantation or need for left ventricular assist device. Serial 24-hour Holter analysis revealed no proarrhythmic effect. No devices malfunctioned or failed for any reason other than end-of-battery life. Throughout the two study phases, EF improved from 22.7 +/- 7% to 28.7 +/- 7% and 37 +/- 13% (P = 0.004), 6-MWT from 418 +/- 99 m to 477 +/- 96 m and 510 +/- 107 m (P = 0.002), MLWHFQ from 36 +/- 21 to 18 +/- 12 and 7 +/- 6 (P = 0.002), peak VO(2) from 13.7 +/- 1.1 to 14.9 +/- 1.9 to 16.2 +/- 2.4 (P = 0.037), and NYHA class from 3 to 1.8 +/- 0.4 to 1.5 +/- 0.7 (P < 0.001). CONCLUSION: CCM therapy appears to be safe and feasible. Proarrhythmic effects of this novel therapy seem unlikely. Preliminary data indicate that CCM gradually and significantly improves systolic performance, symptoms, and functional status. CCM therapy for 7 hours per day is associated with greater dispersion near the mean, emphasizing the need to individually tailor CCM delivery duration. The technique appears to be attractive as an additive treatment for severe HF. Controlled randomized studies are needed to validate this novel concept.

Chronic Disease↗

Ferrous sulfate does not affect mycophenolic acid pharmacokinetics in kidney transplant patients.

BACKGROUND: Oral administration of ferrous-sulfate was reported to decrease intestinal absorption of mycophenolate mofetil (MMF) in healthy Japanese individuals by 90%. METHODS: We examined the effect of a single oral dose of ferrous sulfate on steady-state mycophenolic acid pharmacokinetics in 10 iron-deficient (hypochromic red blood cells >2.5%), Caucasian, long-term kidney graft recipients using a randomized, open-label, crossover design. On days A and B, MMF (1,000 mg) was given orally at 8:00 am. On day C, MMF and ferrous sulfate (105 mg) were coadministered at 8:00 am. On day D, MMF was given at 8:00 am and ferrous sulfate was given orally 4 hours later. RESULTS: The interindividual variability of the 12-hour area under the plasma mycophenolic acid concentration versus time curves (AUC(0-12)) under control conditions was small (89.5 +/- 27.8 and 87.6 +/- 39.1 mg x h/L, respectively). Concomitant or subsequent administration of MMF and ferrous sulfate did not affect the bioavailabilty of MMF (AUC(0-12), 91.9 +/- 30.4 mg x h/L and 96.0 +/- 31.7 mg x h/L). CONCLUSION: Oral therapy of iron deficiency using ferrous sulfate in long-term kidney graft recipients does not impede intestinal absorption of MMF; hence, exposure to this immunosuppressive agent is not reduced.

Administration, Oral↗

Influence of exercise induced hyperlactatemia on retinal blood flow during normo- and hyperglycemia.

PURPOSE: Short term hyperglycemia has previously been shown to induce a blood flow increase in the retina. The mechanism behind this effect is poorly understood. We set out to investigate whether exercise-induced hyperlactatemia may alter the response of retinal blood flow to hyperglycemia. METHODS: We performed a randomized, controlled two-way cross over study comprising 12 healthy subjects, performed a 6-minutes period of dynamic exercise during an euglcaemic or hyperglycaemic insulin clamp. Retinal blood flow was assessed by combined vessel size measurement with the Zeiss retinal vessel analyzer and measurement of red blood cell velocities using bi-directional laser Doppler velocimetry. Retinal and systemic hemodynamic parameters were measured before, immediately after and 10 and 20 minutes after isometric exercise. RESULTS: On the euglycemic study day retinal blood flow increased after dynamic exercise. The maximum increase in retinal blood flow was observed 10 minutes after the end of exercise when lactate plasma concentration peaked. Hyperglycemia increased retinal blood flow under basal conditions, but had no incremental effect during exercise induced hyperlactatemia. CONCLUSIONS: Our results indicate that both lactate and glucose induce an increase in retinal blood flow in healthy humans. This may indicate a common pathway between glucose and lactate induced blood flow changes in the human retina.

Acidosis, Lactic↗

Long-term transcutaneous neuromuscular electrical stimulation in patients with bipolar sensing implantable cardioverter defibrillators: a pilot safety study.

Neuromuscular electrical stimulation (NMES) is an option for increasing thigh muscle strength and endurance capacity in patients with chronic heart failure. Electromagnetic interference (EMI) by the signals with sensing of implantable cardioverter defibrillators (ICDs) is possible. The aim of the present pilot safety study was to test the safety of a long-term NMES in patients with ICDs. Six patients with subpectoral ICDs were subjected to long-term NMES of thigh muscles. Four inpatients received NMES to increase muscle strength, and two outpatients performed NMES as a home treatment to increase endurance capacity. During long-term NMES, all patients together received 14 139 799 biphasic electrical pulses and 412 425 on-phases without adverse events. ICD function after the stimulation period revealed no abnormalities in any patient. These results indicate that long-term NMES of thigh muscles seems to be safe in patients with ICDs, providing that an individual risk is excluded before.

Aged↗

Effect of recombinant factor VIIa on melagatran-induced inhibition of thrombin generation and platelet activation in healthy volunteers.

The objectives were to investigate whether activation of the extrinsic coagulation cascade by recombinant factor VIIa (rFVIIa) reverses the inhibition of thrombin generation and platelet activation by melagatran, the active form of the oral direct thrombin inhibitor ximelagatran. In a single-blind, randomized, parallel-group study, volunteers (20 per group) received a 5-hour intravenous (i.v.) infusion to achieve steady-state melagatran plasma concentrations of approximately 0.5 micromol/L, with a single i.v. bolus of rFVIIa (90 microg/kg) or placebo at 60 minutes. Prothrombin fragment 1+2, thrombin-anti-thrombin complex, fibrinopeptide A, beta-thromboglobulin, and thrombin-activatable fibrinolysis inhibitor were quantified for venous and shed blood. Activated partial thromboplastin time (APTT), prothrombin time (PT), endogenous thrombin potential, thrombus precursor protein (TpP), and plasmin-alpha(2)-antiplasmin complex concentrations were determined in venous blood. Shed blood volume was measured. Melagatran reduced markers of thrombin generation and platelet activation in shed blood and prolonged APTT. rFVIIa increased FVIIa activity, PT, and TpP in venous blood. All other parameters were unaffected. In conclusion, rFVIIa did not reverse the anticoagulant effects of high constant concentrations of melagatran. However, the potential value of higher, continuous or repeated doses of rFVIIa or its use with lower melagatran concentrations has not been excluded.

Adult↗

The cholinergic system controls ghrelin release and ghrelin-induced growth hormone release in humans.

The stomach-derived peptide hormone ghrelin induces appetite and GH release. Several ghrelin actions are possibly mediated and modulated by the central cholinergic system. The aim of this study was to investigate the influence of the unspecific cholinergic antagonist atropine and the acetylcholine esterase inhibitor pyridostigmine, a cholinergic enhancer on ghrelin plasma concentrations and ghrelin-induced GH release. We investigated plasma ghrelin concentrations, ghrelin-induced GH release, and glucose and insulin concentrations after administration of atropine or pyridostigmine, and ghrelin (in two different doses, 0.25 and 1 microg/kg body weight), alone and in combination in a randomized, double-blind, placebo-controlled, crossover study design on 12 young, healthy male volunteers. Atropine alone significantly reduced fasting ghrelin levels by 25%, whereas under pyridostigmine alone ghrelin levels were unaltered. Ghrelin in combination with atropine induced significantly reduced GH concentrations compared with ghrelin administration alone for both ghrelin doses, whereas ghrelin-induced GH peak concentrations and areas under the curve were not enhanced by pyridostigmine treatment. These results suggest that, in humans, fasting ghrelin concentrations might be under cholinergic control and that the cholinergic system appears to modulate ghrelin-induced GH release.

Adult↗

Weight loss reduces circulating asymmetrical dimethylarginine concentrations in morbidly obese women.

The endogenous nitric oxide-synthase inhibitor asymmetrical dimethyl-L-arginine (ADMA) is elevated in patients with increased risk for arteriosclerosis. Obesity is a risk factor for cardiovascular disease. We measured plasma ADMA concentrations in morbidly obese women before and after weight loss following gastroplastic surgery. ADMA and symmetrical dimethyl-L-arginine concentrations were analyzed by HPLC from 34 female patients (age 41 +/- 7 yr) with a body mass index (BMI) of 49 +/- 1 kg/m2 before and 14 months after vertical ring gastroplasty. Age-matched healthy women (BMI < 25 kg/m2; n = 24) were studied as controls. After gastroplastic surgery, BMI decreased to 34 +/- 1 kg/m2 in obese women (P < 0.00001), and ADMA concentrations were reduced from 1.06 +/- 0.06 micromol/liter at baseline to 0.81 +/- 0.04 micromol/liter after weight loss (P < 0.00001). Symmetrical dimethyl-L-arginine plasma levels were not affected. ADMA correlated with high-sensitivity C-reactive protein at baseline (r = 0.42; P < 0.05) and after weight loss (r = 0.56; P < 0.005). No association with blood pressure or plasma lipids could be observed. ADMA concentrations were lower in controls (0.68 +/- 0.04 micromol/liter; P < 0.05) compared with obese patients before or after weight reduction. The decrease of highly elevated ADMA concentrations in morbidly obese patients is paralleled by improvement of parameters associated with the metabolic syndrome after weight loss.

Adult↗

Inflammation-induced vasoconstrictor hyporeactivity is caused by oxidative stress.

OBJECTIVES: We sought to determine the role of oxidative stress in the development of vascular dysfunction in inflammation. BACKGROUND: Hyporeactivity to catecholamines and other vasoconstrictors is present in acute inflammation. Because oxidative stress plays a significant role in inflammation, impaired responsiveness may be overcome by anti-oxidants. METHODS: In randomized, double-blind, cross-over studies, forearm blood flow (FBF) responses to norepinephrine (NE), angiotensin II (ANG II), and vasopressin (VP) were assessed before and 4 h after induction of systemic inflammation by low doses of Escherichia coli endotoxin (lipopolysaccharide [LPS], 20 IU/kg intravenously) or after placebo in healthy volunteers. Furthermore, the effect of intra-arterial vitamin C (24 mg/min) or placebo on NE-induced or ANG II-induced vasoconstriction was studied after LPS. RESULTS: Administration of LPS caused systemic and forearm vasodilation, increased white blood cell count, elevated body temperature, and reduced vitamin C plasma concentrations. Lipopolysaccharide decreased the responses of FBF to NE by 59%, to ANG II by 25%, and to VP by 51% (n = 9, p < 0.05, all effects). Co-administration of vitamin C completely restored the response to NE and to ANG II, which was comparable to that observed under baseline conditions (n = 8). CONCLUSIONS: E. coli-endotoxemia reduces FBF responsiveness to vasoconstrictors. The hyporeactivity can be corrected by high doses of vitamin C, suggesting that oxidative stress may represent an important target for inflammation-induced impaired vascular function.

Adult↗

Safety of a combined strength and endurance training using neuromuscular electrical stimulation of thigh muscles in patients with heart failure and bipolar sensing cardiac pacemakers.

Neuromuscular electrical stimulation (NMES) is an effective and non-strenuous therapy to enhance the strength and endurance capacity of the skeletal muscles in patients with severe chronic heart failure. NMES in patients with pacemakers is controversial because potential electromagnetic interference may result in pacemaker malfunction. Therefore, such patients are in general excluded from NMES. The aim of this pilot study was to evaluate the safety of a combined NMES protocol to increase strength and endurance capacity of the skeletal muscles in patients with heart failure and implanted pacemakers. Seven patients with chronic heart failure and implanted cardiac pacemakers with bipolar sensing leads received NMES treatment of thigh muscles, using a combined protocol comprising biphasic, symmetric, rectangular constant current impulses at different frequencies (8-50 Hz), pulse width up to 60 s (8 Hz), 4 s (15 Hz), 4 s (30 Hz), and 6 s (50 Hz), and amplitudes up to +/- 100 mA (all frequencies) applied to both knee extensor and flexor muscles via surface electrodes (8 x 13 cm each). Acute electromagnetic interference during a safety procedure (telemetric monitoring) before therapeutic NMES application was not observed in any of the patients. The 7 patients received during 20 therapeutic NMES sessions a total of 23,380 on-phases, comprising 2194.08 x 10(3) biphasic electrical pulses, without adverse events. Heart rate monitoring during stimulation and pacemaker interrogation revealed no abnormalities. NMES treatment of thigh muscles using a combined NMES protocol to enhance strength and endurance capacity appears to be safe in patients with heart failure and implanted pacemakers with bipolar sensing, as far as the described electrode configuration and parameter range is applied.

Adult↗

Consistent pharmacokinetics of the oral direct thrombin inhibitor ximelagatran in patients with nonvalvular atrial fibrillation and in healthy subjects.

OBJECTIVE: To investigate the influence of nonvalvular atrial fibrillation (NVAF) on the pharmacokinetic (PK) properties of the oral direct thrombin inhibitor ximelagatran and its active form, melagatran. METHODS: In an open study, 12 patients with persistent NVAF and 12 age- and gender-matched, healthy control subjects received a 10-min intravenous (i.v.) infusion of 2.66 mg melagatran followed by oral ximelagatran, 36 mg twice daily, for the subsequent five study days. Plasma and urine samples for PK analyses were collected after i.v. and single and repeated oral dosing. RESULTS: The oral absorption of ximelagatran was rapid, and maximum plasma concentrations of ximelagatran (Cmax) were achieved at about 1 h post-dosing. There were no differences between NVAF patients and controls for the area under the plasma concentration versus time curve, Cmax, half-life (t1/2), or bioavailability (F) of melagatran after oral dosing with ximelagatran. The Cmax of melagatran, formed by the rapid bioconversion of ximelagatran, occurred approximately 3 h post-dosing. The geometric means of the t1/2 for melagatran were 4.0 h and 4.2 h for the first and last doses, respectively, in patients, and 3.5 h and 3.7 h, respectively, in controls. Geometric means of F of melagatran following oral administration of ximelagatran were 22% and 24% for the first and last doses, respectively, in patients and 21% and 23%, respectively, in controls. Approximately 80% of the i.v. dose of melagatran was excreted in urine in patients and in controls. CONCLUSION: The PK properties of oral ximelagatran and i.v. melagatran in elderly patients with NVAF are consistent with those in matched, healthy controls.

Administration, Oral↗

The ocular hemodynamic response to nitric oxide synthase inhibition is unaltered in patients with early type I diabetes.

BACKGROUND: An impaired ocular hemodynamic response to systemic nitric oxide synthesis inhibition has been demonstrated in patients with long-standing insulin-dependent diabetes mellitus. It is unclear whether this altered responsiveness is already detectable in early uncomplicated type I diabetes. METHODS: The effect of the nitric oxide synthase inhibitor N(G)-monomethyl- l-arginine (L-NMMA) was studied in 10 male patients with early type I diabetes under euglycemic conditions and 10 healthy matched control subjects in a single (analyst) blinded cohort study design. Changes in ocular hemodynamics (fundus pulsation amplitude, mean flow velocity in the ophthalmic artery) and in pulse rate and mean blood pressure were measured in response to systemic intravenous doses of 1.5, 3, and 6 mg/kg L-NMMA. RESULTS: L-NMMA dose-dependently and significantly decreased fundus pulsation amplitude (-21.0% vs -23.3% in diabetics and controls, respectively), mean flow velocity in the ophthalmic artery (-12.3% vs -10.8%) and pulse rate (-15.4% vs -16.6%) and increased mean arterial pressure (+19.5% vs +14.7%). The ocular and systemic hemodynamic effects of L-NMMA were not different between patients with diabetes and controls. CONCLUSION: The responsiveness of the choroidal vasculature and the ophthalmic artery to L-NMMA is not altered in early type 1 diabetes. An impaired hemodynamic response to nitric oxide synthesis inhibition in diabetes is therefore not caused by a primary defect but rather due to altered vascular responsiveness secondary to long-standing disease.

Adult↗

Quality of life in patients with non-metastatic differentiated thyroid cancer under thyroxine supplementation therapy.

GOALS: When thyroid and other cancers are "cured" it is often assumed that the patients are able to resume their normal lives. This was a cross-sectional study to evaluate health-related quality of life (HRQOL) and to identify rehabilitation needs of patients with non-metastatic thyroid cancer under thyroxine supplementation therapy. PATIENTS AND METHODS: Included in the study were 150 consecutive patients with differentiated thyroid cancer (age 52 +/- 14 years, range 25-83 years; male/female 39/111). All patients had a history of total thyroidectomy followed by radioiodine ablation, were free of metastatic disease and under levothyroxine treatment. The mean period since the diagnosis of thyroid cancer was 5.5 +/- 6 years (range 0-23 years). Health-related quality of life was evaluated using the SF-36 Health Survey. The findings were compared with sex- and age-matched reference values. RESULTS: "Role-emotional" and "Vitality" were significantly lower ( P<0.001 and P<0.005, respectively) in the group as a whole ( n = 150). In the subgroup of patients with a recent (less than 1 year) diagnosis of thyroid cancer ( n = 51), however, the following subscales were significantly lower: "Mental Health" ( P<0.01), "Role-emotional" ( P<0.001), "Role-physical" ( P<0.005), "Social functioning" ( P<0.005) and "Vitality" ( P<0.001). Multiple regression analysis identified a significant positive correlation between "Mental Health", "Physical functioning", "Vitality", "Role-emotional" and "Social functioning" with the time since initial diagnosis, and there was also a positive correlation between "Physical functioning", "Bodily pain" and "Role-emotional" with male gender. CONCLUSIONS: These findings indicate that "Vitality", "Role-physical", "Mental Health", "Role-emotional" and "Social functioning" are significantly impaired during the first year after diagnosis. Thereafter, quality of life improves correlating with the time since initial diagnosis. However, "Vitality" and "Role-emotional" remain permanently impaired in thyroid cancer patients. A multidisciplinary rehabilitation concept should include psychological support and an early start to exercise to improve physical performance of these patients leading to better HRQOL and to help them fulfill their social role earlier.

Adult↗

Effects of ximelagatran, an oral direct thrombin inhibitor, r-hirudin and enoxaparin on thrombin generation and platelet activation in healthy male subjects.

OBJECTIVES: The effects of ximelagatran, an oral direct thrombin inhibitor (DTI), recombinant hirudin (r-hirudin) and enoxaparin on thrombin generation and platelet activation were studied in humans. BACKGROUND: Recombinant hirudin (parenteral DTI) and enoxaparin (low molecular weight heparin) have been demonstrated to be clinically effective in acute coronary syndromes. Ximelagatran is currently under investigation for the prevention and treatment of thromboembolism. The shed blood model allows for the study of thrombin generation and platelet activation in humans in vivo. METHODS: This was an open-label, parallel-group study involving 120 healthy male volunteers randomized to receive one of three oral doses of ximelagatran (15, 30 or 60 mg), r-hirudin (intravenous) or enoxaparin (subcutaneous) at doses demonstrated to be clinically effective in acute coronary syndromes, or to serve as a control. Thrombin generation (prothrombin fragment 1+2 [F1+2] and thrombin-antithrombin complex [TAT]) and platelet activation (beta-thromboglobulin [beta-TG]) biomarkers were studied using a shed blood model involving blood collection from skin incisions made using standardized bleeding time devices. RESULTS: Oral ximelagatran, intravenous r-hirudin and subcutaneous enoxaparin rapidly and significantly (p < 0.05) decreased F1+2, TAT and beta-TG levels in shed blood, indicating inhibition of thrombin generation and platelet activation. Statistically significant concentration (melagatran, the active form of ximelagatran)-response relationships for F1+2 (p = 0.005), TAT (p = 0.005) and beta-TG (p < 0.001) levels, with IC(50)s of 0.376 (F1+2), 0.163 (TAT) and 0.115 (beta-TG) micromol/l, were detected. Melagatran showed dose-proportional pharmacokinetics with low variability. All drugs were well tolerated. CONCLUSIONS: Oral administration of the DTI ximelagatran resulted in a rapid inhibition of both thrombin generation and platelet activation in a concentration-dependent manner using a human shed blood model. The inhibition of thrombin generation by 60 mg ximelagatran was comparable to that observed with doses of r-hirudin and enoxaparin demonstrated to be effective for the treatment of acute coronary syndromes.

Administration, Oral↗

[Cost reduction with project based prescription of generic ACE inhibitors].

BACKGROUND: Increasing drug costs are an economic burden for the health insurance system. AIM: The regional drug prescription pattern for ACE inhibitors in the Austrian county Burgenland was compared for patients discharged from hospital and those in primary care. Furthermore, the potential cost reduction by voluntary prescription of cheaper generic drugs was estimated in the project "Bessere Therapie zum besseren Preis". METHODS: Following consensual analysis of the regional cross-sectional study, a cheaper generic of the most cost-intensive class of ACE-inhibitor drugs should be prescribed at internal medicine wards and in primary care. The number of prescriptions for patients from the largest health insurance company BGKK was studied and the costs were calculated. RESULTS: Of the 1347 patients discharged during October 1999 from internal medicine departments of four different hospitals 879 patients received a total of 1440 cardiovascular drugs. The regional prescription pattern at hospitals matched that of physicians in primary care. Between the second quarter of 2000 and 2001, the prescription of ACE inhibitor drugs increased by project advertising from 23,627 packages by 13.1%, and drug costs in this group were reduced by [symbol: see text] 29,778 in this quarter (7.3% of costs). The number of Enalapril prescriptions increased by 33.4% with a percentual portion of generic Enalapril of 57.3%, and in the rest of Austria by 16.9% with 45.0% generics. CONCLUSION: Consensus based projects are appropriate pharmacoeconomic interventions to change prescription patterns, increase the use of drugs and reduce the increasing cost requirements.

Angiotensin-Converting Enzyme Inhibitors↗

Propranolol and atropine do not alter choroidal blood flow regulation during isometric exercise in healthy humans.

Recent studies indicate that the human choroid has a considerable capacity to keep blood flow constant despite exercise-induced increases in perfusion pressure. The mechanisms underlying this vasoconstrictor response remain unclear. We hypothesized that pharmacological modulation of the autonomic nervous system may alter the choroidal pressure/flow relationship during squatting. To test this hypothesis, we performed a randomized, double-masked, placebo-controlled, three-way crossover study in 15 healthy male volunteers. Subjects received, on different study days, intravenous infusions of the beta-adrenoceptor antagonist propranolol, the muscarinic receptor antagonist atropine, or placebo. During these infusions, subjects performed squatting for 6 min. Choroidal blood flow was assessed with laser Doppler flowmetry and ocular perfusion pressure (OPP) was calculated from mean arterial pressure and intraocular pressure. As expected, propranolol reduced basal pulse rate, whereas atropine increased pulse rate, indicating that the drugs were administered at systemically effective doses. None of the drugs altered the choroidal pressure/flow relationship during isometric exercise. These data indicate that the regulatory vasoconstrictor capacity of the choroid during exercise is not affected by systemic blockade of beta-adrenoceptors or muscarinic receptors.

Adrenergic beta-Antagonists↗