[Assessment of SUSARs. Clinical evaluation of single cases in terms of regulatory requirements]. / Bewertung von SUSARs. Die klinische Bewertung des Einzelfalles vor dem Hintergrund regulatorischer Vorgaben.

In the course of implementing the European directives on pharmaceutical law, focus is set on suspected unexpected serious adverse reactions (SUSARs). SUSARs are essential for expedited reporting to authorities and ethics committees. During on-line monitoring of the study, the investigator documents all adverse events. Serious adverse events are forwarded to the sponsor in due time. The sponsor identifies SUSARs for expedited reporting. Clinical causality assessment between the investigational product and the adverse event is substantial in this process. This requires a balanced clinical assessment of all case relevant aspects and information available reflecting the complexity of the specific case, which cannot be covered by algorithms in general. In the setting of on-line monitoring, SUSARs ensure the safety of the patient and the study. In addition, SUSARs are relevant for generation of the safety profile of the substance.

Sequences and antimycoplasmic properties of longibrachins LGB II and LGB III, two novel 20-residue peptaibols from Trichoderma longibrachiatum.

Longibrachins are members of the class of natural Aib-containing peptides designated as peptaibols. Six longibrachins, LGA I-IV and LGB II and III, were purified from a Trichoderma longibrachiatum strain by a procedure employing several chromatography steps including reversed-phase HPLC. The amino acid sequence determination was based on a combination of liquid secondary ion mass spectrometry (LSIMS) and two-dimensional 1H and 13C NMR spectroscopy. Longibrachins are 20-residue peptaibols with a C-terminal phenylalaninol and either neutral (LGA; Gln18) or acidic (LGB; Glu18) character. Longibrachins LGB II and III have novel sequences. Both longibrachins LGA and LGB show significant bactericidal activity against mycoplasmas (Acholeplasma, Mycoplasma, and Spiroplasma), with minimal inhibitory concentrations in the range 1.56-12.5 microM (3-25 micrograms/mL), and also perturb the permeability of membrane bilayers. Longibrachin LGA IV is the most potent of the presently known 18-20-residue peptaibols. The antimicrobial and membrane-perturbing properties of longibrachins, which are described here for the first time, were shown to be correlated.

The complete genome sequence of the murine respiratory pathogen Mycoplasma pulmonis.

Mycoplasma pulmonis is a wall-less eubacterium belonging to the Mollicutes (trivial name, mycoplasmas) and responsible for murine respiratory diseases. The genome of strain UAB CTIP is composed of a single circular 963 879 bp chromosome with a G + C content of 26.6 mol%, i.e. the lowest reported among bacteria, Ureaplasma urealyticum apart. This genome contains 782 putative coding sequences (CDSs) covering 91.4% of its length and a function could be assigned to 486 CDSs whilst 92 matched the gene sequences of hypothetical proteins, leaving 204 CDSs without significant database match. The genome contains a single set of rRNA genes and only 29 tRNAs genes. The replication origin oriC was localized by sequence analysis and by using the G + C skew method. Sequence polymorphisms within stretches of repeated nucleotides generate phase-variable protein antigens whilst a recombinase gene is likely to catalyse the site-specific DNA inversions in major M.pulmonis surface antigens. Furthermore, a hemolysin, secreted nucleases and a glyco-protease are predicted virulence factors. Surprisingly, several of the genes previously reported to be essential for a self-replicating minimal cell are missing in the M.pulmonis genome although this one is larger than the other mycoplasma genomes fully sequenced until now.

Biochemical and antigenic characterisation of Mycoplasma gallisepticum membrane proteins P52 and P67 (pMGA).

Two membrane proteins from the avian pathogen Mycoplasma gallisepticum have been previously purified using a simple, efficient and non-denaturing method: a lipoprotein P67 (pMGA) and P52. In the current study, the lipid part of P67 was chemically analysed. The molecular structure of the lipoprotein-lipid component was determined to be S-glyceryl cysteine with two O-ester-linked acyl chains. Fatty acid analysis of the purified P67 indicated a heterogeneous composition: palmitic acid (16:0)>stearic acid (18:0)>oleic acid (18:1c)>myristic acid (14:0), with 16:0 as the major component. These findings, along with previously published results, support the conclusion that P67 is pMGA1.2, a true membrane-associated lipoprotein although not N-acylated. In contrast to P67, P52 is not a lipoprotein. Topological experiments using in situ treatment with proteases and growth inhibition in the presence of anti-P52 serum provided evidence of the surface exposition of the polypeptide. The N-terminal sequence of P52 was found to be similar to the dihydrolipoamide acetyltransferase from several mollicutes; this enzyme is a membrane-associated component of the pyruvate dehydrogenase complex. Immunoblotting techniques revealed that the surface antigens P52 and P67 were specific to the species M. gallisepticum and the closely related species M. imitans. No antigenic difference was revealed within these species with the anti-P52 serum, while anti-P67 serum confirmed the antigenic variability of P67. The potential of P52 and P67 as antigens in serological diagnosis tests or as candidates for anti-mycoplasma subunit vaccines is discussed.

Cardiovascular and neuroendocrine responses to water immersion in compensated heart failure.

The hypothesis was tested that cardiovascular and neuroendocrine (norepinephrine, renin, and vasopressin) responses to central blood volume expansion are blunted in compensated heart failure (HF). Nine HF patients [New York Heart Association class II-III, ejection fraction = 0.28 +/- 0.02 (SE)] and 10 age-matched controls (ejection fraction = 0.68 +/- 0.03) underwent 30 min of thermoneutral (34.7 +/- 0.02 degrees C) water immersion (WI) to the xiphoid process. WI increased (P < 0.05) central venous pressure by 3.7 +/- 0.6 and 3.2 +/- 0.4 mmHg and stroke volume index by 12.2 +/- 2.1 and 7.2 +/- 2.1 ml. beat(-1). m(-2) in controls and HF patients, respectively. During WI, systemic vascular resistance decreased (P < 0.05) similarly by 365 +/- 66 and 582 +/- 227 dyn. s. cm(-5) in controls and HF patients, respectively. Forearm subcutaneous vascular resistance decreased by 19 +/- 7% (P < 0.05) in controls but did not change in HF patients. Heart rate decreased less during WI in HF patients, whereas release of norepinephrine, renin, and vasopressin was suppressed similarly in the two groups. We suggest that reflex control of forearm vascular beds and heart rate is blunted in compensated HF but that baroreflex-mediated systemic vasodilatation and neuroendocrine responses to central blood volume expansion are preserved.

Isolation of dermatoxin from frog skin, an antibacterial peptide encoded by a novel member of the dermaseptin genes family.

A 32-residue peptide, named dermatoxin, has been extracted from the skin of a single specimen of the tree frog Phyllomedusa bicolor, and purified to homogeneity using a four-step protocol. Mass spectral analysis and sequencing of the purified peptide, as well as chemical synthesis and cDNA analysis were consistent with the structure: SLGSFLKGVGTTLASVGKVVSDQF GKLLQAGQ. This peptide proved to be bactericidal towards mollicutes (wall-less eubacteria) and Gram-positive eubacteria, and also, though to a lesser extent, towards Gram-negative eubacteria. Measurement of the bacterial membrane potential revealed that the plasma membrane is the primary target of dermatoxin. Observation of bacterial cells using reflected light fluorescence microscopy after DNA-staining was consistent with a mechanism of cell killing based upon the alteration of membrane permeability rather than membrane solubilization, very likely by forming ion-conducting channels through the plasma membrane. CD spectroscopy and secondary structure predictions indicated that dermatoxin assumes an amphipathic alpha-helical conformation in low polarity media which mimic the lipophilicity of the membrane of target microorganisms. PCR analysis coupled with cDNA cloning and sequencing revealed that dermatoxin is expressed in the skin, the intestine and the brain. Preprodermatoxin from the brain and the intestine have the same sequence as the skin preproform except for two amino-acid substitutions in the preproregion of the brain precursor. The dermatoxin precursor displayed the characteristic features of preprodermaseptins, a family of peptide precursors found in the skin of Phyllomedusa ssp. Precursors of this family have a common N-terminal preproregion followed by markedly different C-terminal domains that give rise to 19-34-residue peptide antibiotics named dermaseptins B and phylloxin, and to the D-amino-acid-containing opioid heptapeptides dermorphins and deltorphins. Because the structures and cidal mechanisms of dermatoxin, dermaseptins B and phylloxin are very different, dermatoxin extends the repertoire of structurally and functionally diverse peptides derived from the rapidly evolving C-terminal domains of precursors of the dermaseptins family.

Plasma disappearance of albumin and impact of capillary thickness in idiopathic dilated cardiomyopathy and after heart transplantation.

BACKGROUND-The increased plasma disappearance of albumin has previously been described in decompensated congestive heart failure (CHF); this disappearance normalized after diuretic treatment. Cardiac transplantation (HTX) and current medical treatment affect microvascular structure and function. We investigated the plasma disappearance of albumin and the impact of microvascular thickness and electrostatic properties in patients with compensated CHF and after HTX. METHODS AND RESULTS-The fraction of intravascular albumin that passes to the extravascular space per unit time, as determined from the plasma disappearance of intravenously injected (131)I-labeled albumin, was increased to 7.8+/-1.7% in 16 patients with CHF compared with 18 controls (6.5+/-1.9%, P<0.05); these levels normalized after HTX (5.8+/-2.6%, P<0.01, n=17). The change in ratio between (131)I-albumin and simultaneously injected negatively charged glycosylated (125)I-albumin (selectivity index, >1/hour in controls) was lower in patients with HTX (0.993+/-0. 022/hour) than in controls (1.008+/-0.019/hour; P<0.05), which indicated a relatively increased plasma disappearance of negatively charged albumin in HTX patients. Capillary basement membrane thickness was evaluated semiquantitatively from skin biopsies and showed no difference in the 3 groups (control, CHF, and HTX patients). However, in all 3 study groups, subjects with thicker capillary basement membranes had lower albumin escape rates (6.1+/-1. 8%, n=32, versus 7.6+/-2.6% in subjects without thickening of capillary basement membranes, n=19; P<0.05). CONCLUSIONS-The plasma disappearance of albumin increased in patients with compensated CHF and it normalized after HTX. The present normalized capillary basement thicknesses in patients with CHF and the direct association between this parameter and plasma albumin disappearance indicate that previous compensatory microvascular basement membrane growth results in restricted permeability. Microvascular electrostatic properties did not relate to plasma albumin disappearance.

Plasma clearance of polyfructosan and extracellular body fluid distribution in idiopathic dilated cardiomyopathy and after heart transplantation.

The total extracellular fluid volume and distribution in plasma and interstitial spaces, and the microvascular permeability properties were studied in 16 nonedematous patients with congestive heart failure (CHF) due to idiopathic dilated cardiomyopathy and 17 such patients who underwent heart transplantation (HT) by analyzing the 3-hour plasma disappearance curve of polyfructosan. Eighteen healthy subjects served as controls. Polyfructosan (3.5 kD) is an extracellular marker and inulin analog transported almost solely by diffusion. The initial capillary membrane plasma clearance (i.e., the permeability-surface area product), the interstitial plasma clearance determined at 10 minutes (clearance[10), and the extracellular volume were determined from the polyfructosan curves. I-131-albumin was used as a plasma volume reference. Permeability-surface area product was elevated in both patient groups (6.6 +/- 1.9 ml/ kg/min in the CHF group and 6.7 +/- 2.0 ml/kg/min in the HT group vs 5.1 +/- 1.3 ml/kg/min in controls, p <0.01 for both), whereas clearance(10) was normalized in the HT group (4.5 +/- 0.9 ml/kg/min in the HT group, 4.4 +/- 0.7 ml/kg/min in controls vs 5.0 +/- 0.9 ml/kg/ min in the CHF group, p <0.1 and p <0.05, respectively). The normalization of interstitial plasma clearance of polyfructosan was associated with time since HT (r = 0.49, p <0.05). Plasma volumes were similar in all 3 groups (41 +/- 8 ml/kg in controls, 44 +/- 13 in the CHF group and 39 +/- 8 in the HT group). In contrast, total extracellular volume was elevated in both patients groups (177 +/- 27 ml/kg in the CHF group and 173 +/-27 in the HT group vs 152 +/- 12 in controls, p <0.01). The results strongly suggest a microvascular permeability defect in both patient groups that perhaps plays a role in the extravascular distribution of the excess extracellular fluid volume.

Assessment of continuous skeletal muscle blood flow during exercise in humans.

The ability to measure regional blood flow from exercising skeletal muscles is of great interest. However, noninvasive techniques such as venous occlusion plethysmography and pulsed Doppler duplex ultrasonography only allow determination of blood flow at rest. The aim of our study was to investigate the influence of position on continuous measured skeletal muscle blood flow response in the upright and supine positions during graded maximal exercise by means of the local (133)Xenon washout technique with portable CdTe(Cl) detectors. Fifteen healthy subjects (8 women and 7 men, mean age 46 +/- 11 years) performed graded maximal bicycle exercise in both supine and upright positions in random order on 2 subsequent days. Blood flow in the musculus tibialis anterior was measured using the local (133)Xenon washout technique. A total of 55-110 MBq of (133)Xenon dissolved in isotonic saline was injected intramuscularly and the gamma emission was registered by light-weight portable CdTe(Cl) detectors. During supine exercise skeletal muscle blood flow increased continuously with increasing work load. However, during upright exercise blood flow increased only at the initial three work loads, then it decreased gradually. Immediately after exercise blood flow returned to preexercise values for both positions. The skeletal muscle blood flow at maximum work load for each subject was 74% (relative flow values) (P < 0.05) higher in the supine compared with the upright position. There was no significant difference in absolute or relative blood flow values at similar time points. Exercise time was longer in the supine (1345 +/- 548 s) compared with the upright position (1148 +/- 453 s) (P < 0.005). The local (133)Xenon washout technique with portable CdTe(Cl) detectors allows continuous determination of skeletal muscle blood flow during graded bicycle exercise in supine and upright positions. Furthermore, blood flow at maximum work load and exercise time was increased in supine compared with upright exercise.

Calf blood flow during prolonged tilt in idiopathic dilated cardiomyopathy and after cardiac transplantation.

In severe congestive heart failure (CHF), abnormal reflex control of calf blood flow during brief head-up tilt that appears to normalize after transplantation (HTX) may be present during prolonged observation also. Therefore, we studied the effect of prolonged (30 min) 50 degrees head-up tilt on calf skeletal muscle blood flow measured by the local (133)Xe washout method in CHF and after HTX and in patients with the presence vs. absence of native right atrium (+PNA and -PNA, respectively). During brief head-up tilt, skeletal muscle blood flow increased 13 +/- 42% in 9 severe CHF patients in contrast to a -28 +/- 22% decrease (P < 0.01) in 11 control subjects, -24 +/- 30% decrease in 15 moderate CHF patients (P < 0.05), -25 +/- 14% decrease in 12 patients with recent HTX (P < 0.01), and -21 +/- 24% decrease in 8 patients with distant HTX (P = 0.06). However, during sustained tilt, blood flow declined to similar levels of that in the other groups in severe CHF. HTX -PNA vs. +PNA showed blunted skeletal muscle vasomotor control (P < 0.05) and a higher systolic blood pressure (139 +/- 14 vs. 125 +/- 15 mmHg, P < 0.05) and heart rate (92 +/- 10 vs. 83 +/- 8 beats/min, P < 0.05). Thus paradox vasodilatation of calf skeletal muscle in severe CHF is present only during brief but not prolonged tilt. This may be one explanation of the rare presence of orthostatic intolerance in CHF and implies only a minor possible role for the abnormality in edema pathogenesis. Removal of all right atrium in HTX has an important hemodynamic impact that may possibly affect later clinical outcome.

Effects of passive tilting on capillary filtration in the lower leg in idiopathic dilated cardiomyopathy and after heart transplantation for the same condition.

Abnormal reflex control of the peripheral microvasculature during orthostasis in congestive heart failure (CHF) and after heart transplantation (HT) may cause failure of microvascular homeostasis and peripheral edema. We explored the effect of passive head-up tilt on lower leg capillary filtration measured by strain-gauge plethysmography in 24 patients with CHF, in 20 patients after HT (12 patients with preserved native right atrium, 8 patients without native right atrium), and in 18 controls. We hypothesized that an impaired peripheral microvascular reflex during orthostasis in CHF and HT might allow increased arterial hydrostatic pressure to increase pressure at the capillary level. To identify an impact of changes in arterial hydrostatic pressure, capillary fluid filtration was expressed per mm Hg arterial hydrostatic pressure (capillary filtration coefficient(arterial pressure) [CFC(AP)]) and was measured (1) during elevated venous pressure alone (50 mm Hg venous stasis in supine position), and (2) during elevated hydrostatic pressure at both the venous and arterial side of the vascular tree (head-up tilt with a vertical distance from the right atrium to the strain-gauge of 68 cm of water [50 mmHg]). Elevated venous pressure alone resulted in the highest CFC(AP) in controls (0.79+/-0.28 ml/min x 100 ml mm Hg x 10(-3)+/-SD) versus those with CHF (0.44+/-0.23, p <0.0001) and those after HT (0.54+/-0.22, p <0.01). However, during head-up tilt, CFC(AP) was similar in all 3 groups, because CFC(AP) decreased in controls (to 0.49+/-0.22, p <0.0001), in contrast to unchanged CFC(AP) in those with CHF (0.43+/-0.24) and in those with HT (0.50+/-0.21). HT patients with complete removal of the native right atrium had higher CFC(AP) (0.62+/-0.17) during head-up tilt than patients with preserved native right atrium (0.36+/-0.16, p <0.005). In conclusion, patients with CHF and those after HT have increased capillary filtration to a lesser degree than controls during elevated venous pressure alone. However, during orthostasis this apparent edema-protective mechanism vanishes, probably because of compromised microvascular reflex control. During daily upright activities, this may be one important factor in the edema pathogenesis. The phenomenon is particularly distinct in HT patients without preserved native right atrium.

Interactions between mycoplasma lipoproteins and the host immune system.

Mycoplasmas typically have a number of distinct lipoproteins anchored on the outer face of the plasma membrane. These surface antigens have a potent modulin activity and are preferential targets of the host immune response. However, the variation of some of these lipoproteins provides mycoplasmas with an effective means of evading the host immune defence system.

Correlation between anti-bacterial activity and pore sizes of two classes of voltage-dependent channel-forming peptides.

Anti-bacterial activities were compared for two series of voltage-dependent pore-formers: (i) alamethicin (Alm) and its synthetic analogs (Alm-dUL) where alpha-amino-isobutyric acid residues (Aibs) were replaced by leucines and selected key residues substituted and (ii) homologous voltage sensors of the electric eel sodium channel (repeats S4L45 (III) and S4L45 (IV)). Spiroplasma melliferum, a bacterium related to the mycoplasmas, was used as a target cell. The data show that with respect to growth inhibition, cell deformation and plasma membrane depolarization, the highest efficient peptide remained natural Alm although the minimal inhibitory concentrations of its Leu analogs were within the same range as the parent molecule, except for Alm-dUL P14A. Thus, as for the pore-forming activity observed in artificial membranes and for the toxicity towards mammalian cells, proline-14 proved to be a critical residue for the anti-bacterial activity of alamethicin. Regarding the sodium voltage sensors, their anti-bacterial efficiency was at least 10 times lower although they promoted spiroplasma cell agglutination. The anti-bacterial activities of the peptides were correlated with their pore-forming properties, especially with the apparent and mean number of monomers per conducting aggregate () when both peptide families were considered and, secondly, with mean open times (tau(o)) within each family. This suggests that although they may form 'raft-like' structures, the mechanism underlying anti-bacterial activity of Alm and its active analogs, as well as the S4L45 voltage sensors with the S. melliferum plasma membrane, is predominantly through pore-formation according to the 'barrel-stave' mechanism.

Exercise blod flow and microvascualr distensibility in skeletal muscle normalize after heart transplantation.

This study investigated the effect of heart transplantation (HTX) on reduced exercise blood flow and microvascular stiffness in patients with congestive heart failure (CHF). Skeletal muscle blood flow (SMBF) during graded maximal supine bicycle exercise and microvascular distensibility (i.e., stiffness) were measured in musculus tibialis anterior by the isotope washout method. Measurements were performed in a cross-sectional study with 31 CHF patients and 28 patients, mean 9 months after HTX, and in a longitudinal study in 12 CHF patients before, 3 months, and 14 months after HTX, and in 31 healthy controls. Maximal SMBF: In the cross-sectional study, maximal SMBF was reduced in severe CHF patients (3.6 +/- 2.5 mL (100 g min)(-1)) and increased after HTX (7.7 +/- 4.8; p < 0.01 versus controls (11 +/- 4.1). Maximal SMBF was reduced in CHF patients (5.8 +/- 4.0) and reversed to normalization 3 months after HTX (10.3 +/- 4.4) in the longitudinal study. Microvascular distensibility: The distensibility was reduced (severe CHF, 12 +/- 8%; moderate CHF, 23 +/- 14%) in the cross-sectional study and increased after HTX towards normalization (38 +/-20%; controls: 44 +/- 17). In the longitudinal study, distensibility in CHF patients (14 +/- 6%) increased gradually to 32 +/- 12% (p < 0.005) at 3 months and normalized 14 months after HTX (46 +/- 17%). HTX gradually reversed the reduced SMBF and microvascular distensibility in CHF patients towards normalization.

Exercise skeletal muscle blood flow is related to peripheral microvascular stiffness in idiopathic dilated cardiomyopathy.

Peripheral microvascular function plays an important role in congestive heart failure (CHF). Decreased exercise blood flow and microvascular dysfunction have been described in CHF and both factors are regarded as parameters that might influence exercise capacity in these patients. Whether these factors are related to or can be characterized in clinical severity of CHF has not been elucidated in this population. Skeletal muscle blood flow (SMBF) was measured continuously noninvasively, by means of the local isotope washout technique using (133)Xenon, in musculus tibialis anterior during graded maximal supine bicycle exercise. The distensibility in skeletal muscle was measured in a papaverine-relaxed vascular bed using (99m)Tc-pertechnetate. The investigation included 20 patients with moderate CHF (NYHA II), 11 patients with severe CHF (NYHA III, IV) due to idiopathic dilated cardiomyopathy (IDCM), and 31 age-matched healthy subjects. The maximal SMBF level was significantly lower in severe CHF (3.6 +/- 2.5 (ml x (100 g x min)(-1))) compared with moderate CHF (8.6 +/- 5.1 (ml x (100 g x min)(-1)); P < 0.005) and controls (11.0 +/- 4.1 (ml x (100 g x min)(-1)); P < 0.0001), but similar between moderate CHF and controls. Distensibility in skeletal muscle was decreased in severe CHF (12 +/- 8%) compared with controls (44 +/- 17%; P < 0.0001 vs severe CHF) and decreased with increasing severity of CHF (moderate CHF, 23 +/- 14%; P < 0.0005 vs controls). In CHF patients, a relationship was demonstrated between skeletal muscle distensibility and the maximal SMBF (P < 0.0001; r = 0.70). Moreover, maximal SMBF correlated directly to exercise time (P < 0.005; r = 0.54). Patients with CHF have reduced exercise SMBF, which may be a limiting factor for the reduced maximal exercise capacity. Moreover, microvascular distensibility in skeletal muscle is reduced and correlates to maximal exercise SMBF. Furthermore, maximal SMBF correlates to exercise time. This implies that increased skeletal muscle microvascular stiffness may contribute to the reduced blood flow during exercise and SMBF may partly limit exercise performance in CHF patients due to IDCM.

Regional blood flow in the calf and plasma endothelin during prolonged orthostasis in humans.

This study tested the hypothesis that circulating plasma levels of the vasoconstrictor endothelin increase during prolonged orthostasis in association with changes in both calf regional blood flow, systemic arterial blood pressure and heart rate, and that the 133Xenon wash-out method can be used for prolonged registration of skeletal muscle blood flow. The simultaneous effects of prolonged orthostasis on plasma endothelin, calf skeletal muscle and subcutaneous blood flow, heart rate and arterial blood pressure were investigated in 13 healthy subjects before, during and after 30 min of 50 degree head-up tilt. Blood flow rate was measured by the local 133Xenon wash-out method in the supine position and during 50 degree head-up tilt. The method was evaluated for skeletal muscle for prolonged observation in the supine position in five subjects and compared with blood flow rates measured with plethysmography. Plasma endothelin was unchanged during head-up tilt, despite a maximal reduction in skeletal muscle blood flow rate of 47% (p<0.001) and subcutaneous blood flow rate of 80% (p<0.01) and a maximal increase in heart rate of 15% (p<0.001) and diastolic (12%, p<0.01) blood pressure. The skeletal muscle wash-out curves for 133Xenon were monoexponential from 30 min after injection and at least during the next hour and correlated with total limb blood flow rate assessed simultaneously with plethysmography (r=0.76, p<0.0001). Circulating endothelin does not appear to be in the first line of regulation of calf microcirculation, systemic arterial blood pressure or heart rate during prolonged orthostasis. The 133Xenon wash-out method can be used for prolonged measurement of skeletal muscle blood flow.

Reversal of peripheral microvascular dysfunction during long-term treatment with the angiotensin-converting enzyme inhibitor fosinopril in congestive heart failure.

BACKGROUND: Treatment with angiotensin-converting enzyme (ACE) inhibitors in congestive heart failure (CHF) improves cardiac and peripheral hemodynamic function and exercise performance. However, studies on the effects of long-term treatment with an ACE inhibitor on the neurogenic and nonneurogenic regulation and structural microangiopathy of the peripheral microvasculature in CHF are lacking. METHODS AND RESULTS: We investigated the effect of 12 weeks of treatment with the ACE inhibitor fosinopril on peripheral microvascular function in a double-blind, placebo-controlled study of 12 patients treated with fosinopril and 10 patients treated with placebo. All had moderate CHF. Microvascular blood flow and resistance were calculated after application of the local isotope washout method in relaxed and nonrelaxed calf vascular beds in the supine position and during head-up tilt. Skeletal muscle vascular resistance was reduced in the fosinopril group (46 +/- 6 to 30 +/- 1 mm Hg.mL-1.100 g.min +/- standard error; P < .05) and differed compared with the effect of placebo (P < .05) where no change was seen (37 +/- 11 to 55 +/- 13 mm Hg.mL-1.100 g.min; not significant [NS]). Also, skin minimal vascular resistance was reduced during fosinopril treatment (13 +/- 0.6 to 11 +/- 0.7 mm Hg.mL-1.100 g.min; P < .05) and differed compared with the effect of placebo (P < .05) with absence of change (12 +/- 1.6 to 14 +/- 1.4 mm Hg.mL-1.100 g.min; NS). CONCLUSIONS: These results suggest that long-term ACE inhibitor treatment with fosinopril in patients with CHF improves hemodynamic status to as far as the peripheral microvascular level in both the relaxed and nonrelaxed microcirculation of the lower leg.

Endothelin and von Willebrand factor as parameters of endothelial function in idiopathic dilated cardiomyopathy: different stimuli for release before and after heart transplantation?

BACKGROUND: Congestive heart failure (CHF) and heart transplantation (HTX) are characterized by endothelial dysfunction as indicated by elevation of markers of endothelial function, including endothelin and von Willebrand factor (vWF). However, previous studies included both patients with idiopathic dilated cardiomyopathy and ischemic heart disease; the latter condition shows endothelial dysfunction, per se. The 2 endothelial factors have different origin and may provide different information about endothelial dysfunction in CHF and after HTX caused by idiopathic dilated cardiomyopathy. METHODS: We investigated plasma endothelin and vWF, the relation between these 2 factors, and determinants of endothelin and vWF plasma levels in 32 healthy controls, 25 patients with CHF, and 22 patients who had HTX; both conditions were caused by idiopathic dilated cardiomyopathy. RESULTS: Plasma endothelin was elevated in CHF (6.8 +/- 3.4 pg/mL) and after HTX (6.1 +/- 2.1) compared with healthy controls (4.0 +/- 1.0, P <.0001 for both). VWF was also elevated in CHF (1.6 +/- 0.6 U/mL) and after HTX (2.6 +/- 1.0) compared with healthy controls (1.0 +/- 0.5, P <.0001 for both). VWF was increased after HTX compared with CHF (P <.001), in contrast to similar endothelin levels in CHF and after HTX. Plasma endothelin and vWF correlated in both CHF (r = 0.65, P <.001) and HTX (r = 0.66, P <. 001) but not in controls. In CHF, New York Heart Association functional class was an independent determinant of vWF (P <.0001) and furosemide dose of endothelin (P <.0001). In cardiac transplant recipients, plasma albumin was an independent determinant of vWF (P <.01), and plasma sodium and furosemide dose were independent determinants of endothelin (P <.01). CONCLUSIONS: Plasma endothelin and vWF were directly correlated in both CHF and after HTX caused by idiopathic dilated cardiomyopathy. However, the production of the 2 factors appeared to be stimulated by different mechanisms and provided different information about endothelial function, as indicated by the different determinants and different response to heart transplantation.