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Biomedical subjects

E Hartter

Publications and source records attributed to E Hartter.

At least 55 records · Page 3Linked to original sources
PubMed1987

Mechanical ventilation with positive end-expiratory pressure decreases release of alpha-atrial natriuretic peptide.

The influence of PEEP during controlled mechanical ventilation (CMV) on plasma levels of alpha-atrial natriuretic peptide (alpha-ANP) was examined in seven patients suffering from acute respiratory failure. The majority of patients were volume-expanded. Samples were drawn from the superior vena cava, right atrium, pulmonary artery, and radial artery. All alpha-ANP levels were significantly depressed by 15 cm H2O PEEP for one hour, when compared to CMV without PEEP. During the PEEP period, cardiac index, creatinine clearance, urinary flow and urinary sodium excretion were decreased. CMV with PEEP of 20 cm H2O depressed peripheral venous plasma levels of alpha-ANP in six volume-expanded healthy volunteers, too. The decreased release of alpha-ANP could be a consequence of atrial compression by the distended lungs and of reduced venous return. We suggest that the decline in plasma alpha-ANP levels contributes to fluid retention and renal dysfunction, which occur frequently during CMV with PEEP. More detailed studies are necessary to confirm our hypothesis.

Adult↗
PubMed1987

HLA-DR antigens in systemic lupus erythematosus: association with specificity of autoantibody responses to nuclear antigens.

HLA-DR antigens and autoantibodies to the nuclear or cytoplasmic antigens Ro/SSA, La/SSB, Sm, and RNP were determined in North American and Austrian patients with systemic lupus erythematosus (SLE). Analysis of the association of antibodies to these ribonucleic acid (RNA)-protein antigens with HLA-DR antigens showed that HLA-DR3 was related to the presence of anti-Ro/SSA or anti-La/SSB, or both. In contrast, anti-Sm or anti-RNP, or both were associated with HLA-DR4. HLA-DR5 was associated with absence of these autoantibodies. The data extend evidence for the complexity and heterogeneity of SLE. Moreover, they indicate that, in SLE, genes linked to those coding for HLA-DR antigens, are related to the specificity of autoantibody responses rather than to the primary immunological abnormalities of this disorder.

Adolescent↗
PubMed1987

[Peripheral and right atrial plasma levels of atrial natriuretic peptide and their relation to mean atrial pressure].

Atrial myocytes produce natriuretic and vasodilating peptides. Animal experiments have shown that atrial natriuretic peptide (ANP) is released after stretching the atria and drained via the coronary vein effluent. In this study ANP-plasma levels were measured in 14 patients. Blood samples were simultaneously collected from the right atrial cavum and from an antecubital vein. In the right atrial samples, ANP-plasma concentrations were significantly higher than in samples drawn from a peripheral vein (140.3 +/- 114.8 pg/ml vs 96.9 +/- 69.2 pg/ml; p less than 0.05), but a significant linear correlation was found between both values (r = 0.88; p less than 0.001). In patients with elevated atrial pressures significantly higher ANP-levels could be detected than in patients with normal atrial pressures (204 +/- 115 pg/ml vs 55.3 +/- 18.5 pg/ml; p less than 0.05). Mean right atrial pressure correlated to ANP-levels in right atrial blood (r = 0.79; p less than 0.001) as well as to ANP-levels in peripheral blood (r = 0.68; p less than 0.01). These results indicate that higher ANP plasma levels can be measured in samples drawn from a site close to ANP production. On the other hand, atrial pressure might influence the amount of circulating ANP.

Adolescent↗
PubMed1987

[Human atrial natriuretic factor (hANF) in liver cirrhosis].

Mean plasma levels of hANF at admission were significantly higher in liver cirrhosis (LC) patients with ascites (93 +/- 11 ng, n = 20; p less than 0.05) than in LC-patients without ascites (32 +/- 14 ng/l, n = 11) or healthy controls (31 +/- 15 ng/l; range: 5-80 ng/l; n = 106). Diuretic treatment of patients with LC and ascites normalised hANF plasma concentrations (44 +/- 14 ng/l; p less than 0.05). Increase of plasma hANF in LC-patients with ascites after acute volume expansion was lower (relative rise: 159%) than in those without ascites (relative rise: 223%). Volume redistribution into the vascular compartment, induced by peritoneovenous shunt implantation in LC-patients with diuretic treatment-refractory ascites, resulted in a sharp increase of plasma hANF levels (344 +/- 87 ng/l = 420% of preoperative concentration). Normal and slightly increased levels of plasma hANF and the appropriate regulation to volume changes suggest an intact control of the hormone in LC-patients. Neither a lack nor an inappropriate secretion of hANF as a cause for sodium retention as postulated by the overflow theory of ascites accumulation could be found in liver cirrhosis.

Ascites↗
PubMed1986

Continuous pump-driven hemofiltration associated with a decline in alpha-atrial natriuretic peptide.

The levels of alpha-atrial natriuretic peptide (ANP) in the right atrium, pulmonary artery, radial artery, and superior vena cava plasma were measured by radioimmunoassay in eight patients with volume-expansion due to different diseases. The alpha-ANP levels were significantly increased, but became decreased after fluid removal by continuous veno-venous hemofiltration. When all alpha-ANP concentrations of different anatomical locations and hemodynamic variables were grouped, pulmonary capillary wedge pressure correlated significantly with all alpha-ANP groups, whereas right atrial mean pressure correlated with alpha-ANP levels in pulmonary artery plasma only. Alpha-ANP concentrations were distinctly lower in superior vena cava plasma than in plasma from the right atrium, pulmonary artery, and radial artery. Since alpha-ANP plays an important role in the homeostasis of sodium and fluid balance, measurement of alpha-ANP concentrations, particularly in right atrium, pulmonary artery, or radial artery plasma, might provide valuable information on the status of the critically ill.

Adult↗
PubMed1986

Radioimmunological determination of arginine vasopressin and human atrial natriuretic peptide after simultaneous extraction from plasma.

Human atrial natriuretic peptide and arginine vasopressin were coextracted from EDTA-plasma with Sep-Pak C18 cartridges, and the hormones were coeluted from the cartridges by a solution containing 900 ml/l of methanol, 5 ml/l of trifluoroacetic acid and 95 ml/l of water. After volume reduction under nitrogen the eluates were lyophilized, dissolved in buffer and aliquots were used for radioimmunological determination of both hormones. Both procedures used delayed addition of [125I]-labelled tracer to enhance sensitivity. Recoveries were 95 +/- 2% for human atrial natriuretic peptide and 96 +/- 3% vor arginine vasopressin (mean +/- SD). Minimal detectable doses were 2 pg/tube of human atrial natriuretic peptide and 0.5 pg/tube of arginine vasopressin (Bo - 3 SD). Intra-assay variabilities were +/- 8% for both tests. Simultaneous extraction of both hormones with high recovery was achieved, thus increasing sensitivity and specificity, at the same time reducing sample volume requirements and technician time.

Adsorption↗
PubMed1986

Radioimmunoassay of atrial natriuretic peptides in human plasma.

The concentration of atrial natriuretic peptide (hANP) in plasma from venous blood of healthy subjects was measured by radioimmunoassay. hANP from 5 mL of EDTA-treated plasma was adsorbed onto Sep-Pak C18 cartridges, which were eluted with methanol/trifluoroacetic acid (5 mL/L), 90/10 by volume. The eluates were concentrated by evaporation under nitrogen and lyophilized. After redissolving the samples in 0.5 mL of sodium phosphate buffer, we incubated 100-microL aliquots with anti-alpha-hANP for 24 h, then added 125I-labeled alpha-hANP tracer; 24 h later, we separated the bound and free fraction by adding an antibody/polyethylene glycol complex as the second antibody. The sensitivity of the assay was 2 pg per tube (B0-3 SEM). In the useful range of B = 15 to 85% of B0, CVs for within-run and between-run precision did not exceed 8 and 12%, respectively. The 50% intercept of the standard curve was at 12 pg per tube. hANP concentrations for 36 healthy adults ranged from 8 to 68 ng/L.

Adult↗
PubMed1986

Plasma levels of atrial natriuretic peptide (ANP) in volume expanded patients: response to fluid removal by continuous pump driven hemofiltration.

Circulating amounts of human atrial natriuretic peptide (hANP) are elevated in congestive heart failure and renal failure. Stretching of cardiac atria, due to volume expansion associated with these diseases, is widely accepted to be the predominant stimulus for release of the hormone. Measurements of hemodynamic parameters as well as plasma concentrations of ANP in the right cardiac atrium, pulmonary artery, radial artery and vena cava superior, before and after continuous veno-venous hemofiltration (CVVH) of critically ill volume expanded patients, proved that ANP might be a useful indicator of fluid balance in these patients.

Atrial Natriuretic Factor↗
PubMed1986

The role of alpha-atrial natriuretic peptide in fluid retention during mechanical ventilation with positive end-expiratory pressure.

Although controlled mechanical ventilation (CMV) with positive end-expiratory pressure (PEEP) has a central place in the treatment of acute respiratory failure (ARF), several side effects of this technique have to be faced. CMV with PEEP may induce pulmonary barotrauma, disturbance of cardiac performance, impairment of renal function and fluid retention. Atrial natriuretic peptides (ANP) are released from the atria upon stretching and play a major role in the control of sodium and fluid balance. Therefore it was logical to determine plasma levels of alpha-ANP in CMV. A study performed in 7 patients suffering from ARF suggested that alpha-ANP plasma levels were depressed during PEEP at 15 cm H2O in comparison with PEEP at 0 cm H2O (ZEEP). The decrease in plasma levels of alpha-ANP was evident in samples taken from superior vena cava, right atrium, pulmonary artery and radial artery as well. The decrease in alpha-ANP was associated with a decline in cardiac index, creatinine clearance, urinary output and urinary sodium excretion. Experiments in volume- expanded healthy volunteers also suggest that CMV with PEEP is able to depress plasma levels of alpha-ANP. The reasons behind the decline in release of alpha-ANP may be atrial compression by the distended lungs and the well-known reduction of venous return to the heart. Other possible factors promoting fluid retention during CMV with PEEP are the decrease in cardiac index and glomerular filtration rate, changes in intrarenal distribution of blood flow, and a stimulation of release of antidiuretic hormone via stretch receptors in the left atrium and baroreceptors in aorta and carotid arteries.

Animals↗
PubMed1986

Thyroid hormones and pericardial effusion may influence plasma levels of atrial natriuretic peptide (ANP) in humans.

Fluid and electrolyte homeostasis is impaired in patients suffering from hypothyroidism and myxedema because myxedema induces retention of salt and water. We have measured plasma levels of human atrial natriuretic peptide (hANP) in 8 female patients who had been totally thyroidectomized because of thyroid carcinoma. Estimations of the hormone were done 4 weeks after diagnostic withdrawal (searching for iodine retaining metastases) and after 2 weeks and 4 weeks of reinitiation of thyroid suppressive therapy by L-thyroxine. hANP levels, although within the normal range (10-80 ng/l) throughout the study, were positively linked to the amount of pericardial effusion (determined by echocardiography), which was highest initially and decreased or vanished with duration of L-thyroxine therapy. Additionally, a positive correlation between thyroid hormone levels and hANP was obtained when the counteracting effect of pericardial effusion was allowed for by partial correlation analysis. Our findings might facilitate explanation of mild polyuria in hyperthyroidism and impaired water excretion in hypothyroidism.

Adult↗
PubMed1982

Regulation of synthesis of catalases and iso-1-cytochrome c in Saccharomyces cerevisiae by glucose, oxygen and heme.

The regulation of the hemoproteins catalase T, catalase A and iso-1-cytochrome c was studied in the yeast Saccharomyces cerevisiae. Levels of catalase T and catalase A mRNAs are low or undetectable in anaerobic and heme-deficient cells, and in wild type strains grown on high glucose concentrations. Regulatory mutants (cgr4 and cas1), which have previously been shown to have high catalase T activity when grown in the absence of oxygen or on high glucose concentrations, have high levels of catalase T mRNA when grown under glucose repression conditions. Whereas no catalase T mRNA could be detected in a heme-deficient (ole3) single mutant, double mutants (ole3 cgr4) and (ole3 cas1) contain mature catalase T mRNA. Catalase T and A mRNAs are accumulated rapidly during adaptation of anaerobic cells to oxygen. Anaerobic and heme-deficient cells lack or have extremely low levels of iso-1-cytochrome c mRNA, which, like catalase mRNAs, is accumulated rapidly during oxygen adaptation. The results obtained demonstrate that glucose, oxygen and heme regulate the synthesis of the hemoproteins studied by controlling mRNA levels. In addition, posttranscriptional, probably translational control has to be postulated at least in the case of catalases, to explain the results obtained.

Catalase↗
PubMed1981

Synthesis of Saccharomyces cerevisiae catalase A in vitro.

mRNA isolated from cells of the yeast Saccharomyces cerevisiae was translated in the cell-free protein synthesis system from wheat germ. Catalase proteins synthesized were isolated from incubation mixtures by immunoadsorption followed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. On dodecyl sulfate gels catalase A synthesized by the wheat germ system migrates like catalase A protein synthesized in vivo. Evidence is presented that yeast catalase T and A synthesized in vivo are no glycoproteins. Synthesis of the two catalase proteins in the wheat germ system and dissimilarity of proteolytic fingerprints of the two proteins demonstrate conclusively that catalase T and A are biogenetically unrelated.

Catalase↗
PubMed1980

The effect of delta-aminolevulinate on catalase T-messenger RNA levels in delta-aminolevulinate synthase-defective mutants of Saccharomyces cerevisiae.

Total RNA was isolated from mutants of Saccharomyces cerevisiae that lack active delta-aminolevulinate synthase and are therefore defective in heme biosynthesis. The RNAs were translated in the cell-free protein synthesis system from wheat germ, and the catalase T synthesized was isolated by immunoadsorption and polyacrylamide gel electrophoresis in the presence of dodecyl sulfate. Little or no catalase T product was detected with RNA from mutant cells grown in the absence of a heme precursor. As judged from in vitro translational capacity, RNA fractions from mutant cells grown in the presence of delta-aminolevulinate contained at least 10 times more catalase T mRNA than RNA from unsupplemented cells.

5-Aminolevulinate Synthetase↗
PubMed1976

Catalase biosynthesis in yeast: formation of catalase A and catalase T during oxygen adaptation of Saccharomyces cerevisiae.

Catalase A from Saccharomyces cerevisiae and its biosynthetic precursors can specifically be immunoprecipitated from extracts obtained from yeast cells grown in the presence of L-[3H]leucine or 59FeCl3. The enzyme and its precursors recognized by a specific antiserum are absent from anaerobic cells. During oxygen adaptation of yeast pre-grown on 0.3% glucose under anaerobic conditions catalase A is formed via a heme-less precursor, probably the apomonomer of the protein, and a heme-containing intermediate. When cells are grown in the presence of Tween 80 the amount of catalase A, but not of catalase T, increases 4-fold. Comparison of the mode of synthesis of catalase T and A shows that no precursor-product relationship exists between the two proteins.

Adaptation, Physiological↗