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Biomedical subjects

W Rascher

Publications and source records attributed to W Rascher.

At least 181 records · Page 10Linked to original sources
PubMed1990

Changes in plasma concentrations of atrial natriuretic peptide during exchange transfusion in premature infants.

Plasma concentrations of atrial natriuretic peptide (ANP) and hemodynamic parameters were investigated in five premature infants undergoing exchange transfusion. Baseline values of ANP were 51.7 +/- 21.2 fmol/ml. Volume depletion by withdrawal of 10 ml blood did not cause changes in systolic blood pressure (79.4 +/- 4.3 vs. 71.4 +/- 5.6 mmHg) and heart rate (115 +/- 5.2 vs. 115 +/- 2.4 b/min). ANP levels in plasma remained unaltered (53.4 +/- 24.9 fmol/ml). Replacement of 10 ml blood increased central venous pressure by 33% and ANP concentration in the plasma by nearly 30%, while heart rate and blood pressure remained unchanged. Our data indicate that the heart of the premature infant responded to acute blood replacement with increased ANP-release, while blood removal appeared not to influence hormone regulation.

Atrial Natriuretic Factor↗
PubMed1990

Determination and characterization of arginine-vasopressin in extracted and unextracted urine and its urinary excretion in normal children and adolescents.

Arginine-vasopressin (AVP) was measured by radioimmunoassay in extracted and unextracted urine using two different antisera. The specificity of the assay was confirmed by high-performance liquid chromatography. By the use of a high specific antiserum, AVP can reliably be measured in unextracted urine. Measurements with a less specific antiserum revealed higher concentrations, probably due to nonspecific binding. The extraction of AVP by the use of octadecasilyl-silica columns is unable to separate the intact hormone from substances interfering with the assay. The urinary AVP excretion in 34 normal children and adolescents ranged between 3.5 and 120 ng/m2/24 h with a mean of 39.1 +/- 29.9 ng/m2/24 h.

Adolescent↗
PubMed1990

Atrial natriuretic peptide, volume and blood pressure regulation during exchange transfusion of the neonates.

Plasma concentrations of atrial natriuretic peptide (ANP) and hemodynamic parameters were investigated in five premature infants undergoing exchange transfusion. Baseline values of ANP were elevated being 51.7 +/- 21.2 fmol/ml. Volume depletion by withdrawal of 10 ml blood did not cause changes in systolic blood pressure (79.4 +/- 4.3 vs 71.4 +/- 5.6 mmHg) and heart rate (115 +/- 5.2 vs 115 +/- 2.4 l/min). ANP levels in plasma remained unaltered (53.4 +/- 24.9 fmol/ml). Volume load of 10 ml blood transfusion increased central venous pressure by 33 per cent and ANP concentration in the plasma nearly by 30 per cent, while heart rate and blood pressure remained unchanged. Our data indicated that the heart of premature infant responds to acute volume load by increased ANP-release, while volume depletion seems not to influence hormone regulation.

Atrial Natriuretic Factor↗
PubMed1990

Cerebrospinal fluid concentrations of atrial natriuretic peptide in children.

Concentrations of atrial natriuretic peptide (ANP) in plasma and in cerebrospinal fluid (CSF) were measured in preterm neonates, in infants and in children with hydrocephalus. Plasma ANP in preterm neonates were elevated compared to infants and children with hydrocephalus. CSF-ANP in all groups were lower than plasma levels. ANP concentrations in the liquor exhibited higher values in children with hydrocephalus. No correlation was found between plasma and CSF-ANP levels while CSF-pressure and ANP concentration in the liquor correlated positively. Our data provide evidence for the existence of a cerebral ANP system in humans. The CSF-ANP system seems to be independent from the systemic, atrial ANP. CSF-ANP may be of great importance in the regulation of water and ion content of central nervous system and probably liquor formation.

Atrial Natriuretic Factor↗
PubMed1990

Atrial natriuretic peptide in patients with decompensated hepatic cirrhosis.

Plasma concentrations of atrial natriuretic peptide (ANP), aldosterone (PA), vasopressin (AVP) and plasma renin activity (PRA) were measured in 15 patients with decompensated cirrhosis of the liver during a control period and subsequently during intravenous administration of albumin. Infusion of hyperoncotic albumin increased diuresis, natriuresis, stimulated ANP secretion and tended to normalize other vasoactive hormone levels in 9 patients (responders), whereas it had no effect in 6 other patients (non-responders). Responders had significantly lower basal levels of ANP and higher ones of PRA, and AVP than non-responders, suggesting that responders had decreased effective intravascular volume. Our data suggest that cirrhotic patients with ascites formation do not represent a homogenous group. In some patients with decompensated cirrhosis a compromised circulatory state with decreased effective circulatory volume induces compensatory changes in several regulatory hormones. It appears that secondary alterations in the plasma concentrations of ANP of cirrhotic patients may occur according to the suspected change of intravascular fluid volume.

Aged↗
PubMed1990

[IgA nephritis: a frequent form of glomerulonephritis in childhood].

Since the introduction of immunohistological techniques in the evaluation of renal biopsies, IGA-nephropathy as first described by Berger in 1968 is diagnosed frequently. The diagnosis of IGA-nephropathy is based upon the demonstration of mesangial IGA deposits. IGA-nephropathy has to be differentiate from post-streptococcal glomerulonephritis, Schönlein-Henoch-nephritis and Lupus-nephritis. With increasing observation periods the prognosis has not been confirmed to be benign, as previously assumed. Every physician interested in paediatrics should be aware of this kind of nephritis, because early renal biopsy is essential for the diagnosis and the estimation of the degree of histological alteration. Furthermore renal biopsy is important for the decision for an aggressive immunosuppressive therapy and therefore for the prognosis.

Adolescent↗
PubMed1990

Prenatal diagnosis and postpartal therapy of fetal obstructions related to the urinary tract.

114 fetal malformations were diagnosed by ultrasound in the years 1983-1987 at our institute. 32 of these malformations involved the urinary tract. Fetuses with multicystic dysplasic kidneys and oligohydramnios have only a poor prognosis. In obstructive uropathy, however, exact antenatal diagnosis makes early leads to specific postpartal urological therapy. Modern ultrasound equipment makes it possible to localize the site of obstruction and/or dilatation in fetuses. The amount of amnion fluid indicates the degree of obstruction and is an important factor the postpartal prognosis of the children. Relieve of obstruction should be the first step of urological therapy directly after birth. We prefer to perform reconstructive surgery as soon as possible in the first 2 to 3 weeks of life. In children with subpelvic stenosis pyeloplasty is performed in the first weeks of life. Our results of 13 pyeloplasties in newborn are favourable. In children with megaureters dynamic scintigraphy or pressure flow studies (Whitaker test) are performed to diagnose or to exclude obstruction as a cause of dilatation (n = 14). In case of obstruction we perform an ureterocutaneostomy (Ring- or Sober procedure) immediately. Urethral valves causing subvesical obstruction could be treated by transvesical antegrade valve ablation, performed in 9 newborn with good success.

Humans↗
PubMed1990

[The diagnostic value of captopril radionuclide nephrography for renovascular hypertension in childhood].

In four children the role of captopril-radionuclide nephrography in the diagnosis of renovascular hypertension was studied. Captopril (0.5-1.0 mg/kg orally) did not affect Iodine-123 Hippuran nephrography in two children with mild renal artery stenosis, but induced an accumulation of the tracer within the kidneys in two children with hemodynamically significant renal artery stenosis. As in adults Iodine 123 Hippuran nephrography appears to be a useful tool to identify patients with significant renal artery stenosis.

Adolescent↗
PubMed1990

[Bilateral adrenal pheochromocytoma. Diagnosis and follow-up using the clonidine test and measurement of plasma neuropeptide Y concentration].

The role of the clonidine suppression test and determination of the plasma concentration of noradrenaline and of neuropeptide Y (NPY) for the diagnosis and monitoring of bilateral pheochromocytoma was studied in a ten year old girl. Prior to tumor removal plasma concentration of noradrenaline (25.9 nmol/l) and NPY (14 pmol/l) were markedly elevated. Inhibition of central sympathetic activity by clonidine (150 micrograms orally) did not lower the plasma concentration of noradrenaline (70.4 nmol/l) and NPY (52.6 pmol/l). However in an adolescent boy with renal hypertension plasma concentration of noradrenaline and NPY fell following clonidine application (noradrenaline from 1.9 to 1.3 nmol/l, NPY from 3.6 to 2.4 pmol/l). After complete removal of the pheochromocytoma noradrenaline and NPY fell back to normal.

Adrenal Gland Neoplasms↗
PubMed1989

[Fluid and electrolyte balance in the postoperative period].

Authors investigated the concentration changes of arginine vasopressin (AVP) and of atrial natriuretic peptide (ANP) in plasma. The renal characteristics of water- and sodium metabolism in the first 24 hours of the postoperative period in 11 children operated with acute appendicitis have been studied. Crystalloid infusion was applied in 60 ml/kg/24 h dose, in 5 cases however, 1 g/kg albumin vas also administered during the operation. In children getting crystalloid infusion (group "A") the initial AVP value was 29.9 +/- 8.8 pg/ml, which further increased to 58.2 +/- 15.2 pg/ml (p 0.05) by the 6. postoperative hour and even in the 24. hour it remained above the physiological value (19.9 +/- 5.3 pg/ml). During the observation time significant Na- and water retention developed. The albumin administration (group "B") stopped the further increase of AVP values, the Na-household remained in equilibrium and the water retention developed only in smaller degree. The ANP plasma concentration of both groups was in the normal range and did not change during observation time. Our data show that for the postoperative water retention first of all the increased AVP activity is responsible. The more intensive AVP secretion may be induced by the relative intravascular hypovolemia since by enhancing the plasma volume the further increase of postoperative hormone activity could be prevented.

Female↗
PubMed1989

Atrial natriuretic peptide and sodium homeostasis in chronic renal failure.

In order to evaluate the possible role of vasoactive hormones in the mechanism of exaggerated sodium loss due to reduced renal mass we measured plasma concentration of atrial natriuretic peptide (ANP), aldosterone, plasma renin activity (PRA), plasma noradrenaline, and dopamine, in 12 children with advanced chronic renal failure (mean CIn 17.8 +/- 2.6, mean +/- SEM, CPAH 93.5 +/- 17 ml/min per 1.73 m2, FENa 7.0 +/- 0.95%). No patient had clinical signs of volume overload. Plasma concentrations of ANP were not significantly different from those of healthy age-matched controls (29.2 +/- 7.2 vs 23.2 +/- 3.1 fmol/ml) and did not correlate with urinary sodium excretion. Plasma concentrations of aldosterone, PRA and noradrenaline, were also within the physiological range, while plasma dopamine levels were elevated (260 +/- 36 vs 98 +/- 11 pg/ml, less than 0.001). Our data do not support the notion that ANP or the renin-aldosterone axis play a major role in the adaptation of remaining nephrons to maintain long-term sodium balance in normotensive children with chronic renal failure.

Adaptation, Physiological↗
PubMed1989

Intra- and extrarenal factors of oedema formation in the nephrotic syndrome.

The role of intra- and extrarenal factors in oedema formation in children with nephrotic syndrome is reviewed. Oedema reflects an abnormal accumulation of fluid within the interstitial tissue. At the capillary level oedema develops when increased lymph flow is no longer effective for the removal of interstitial fluid and the maintenance of intravascular volume. Alterations of intrarenal haemodynamics and tubular sodium reabsorption contribute to sodium retention. Recent studies suggest that during oedema formation reduced effective circulatory volume triggers changes in various hormonal systems, such as renin-angiotensin-aldosterone, noradrenaline, dopamine, vasopressin, prostaglandins and natriuretic factors, which contribute to sodium and water retention. It appears that the release of atrial natriuretic peptide following central volume expansion is responsible for the increased urine flow and natriuresis after intravenous administration of albumin.

Child↗
PubMed1989

Natriuretic factors and lithium clearance in patients with the syndrome of inappropriate antidiuretic hormone (SIADH)

Because the syndrome of inappropriate antidiuretic hormone (SIADH) is a state of disturbed body fluid volume regulation and altered sodium balance we sought to determine if recently described volume regulatory factors were stimulated in SIADH. We measured atrial natriuretic peptide (ANP), endogenous digitalis-like natriuretic factor (EDNF) and urinary free dopamine in SIADH (n = 27). We also determined fractional clearance of lithium (FCLi). The data obtained in SIADH were compared with similar measurements performed in sodium retaining hyponatremias, such as those of heart failure (n = 26), liver cirrhosis (n = 19) and volume contraction (n = 28). We observed: ANP was 19.5 +/- 2.7 fM/ml in SIADH; it was significantly lower than ANP in cardiac failure, but no different from ANP in volume contraction. Urinary free dopamine was 2.2 +/- 0.8 microM/24 h in SIADH; this was significantly higher than in volume contraction and liver cirrhosis. EDNF (259 +/- 42 nM/24 h) and FCLi (21.4 +/- 2%) were both numerically higher in SIADH than in other hyponatremic disorders; however, the differences did not achieve significance. In conclusion, our observations did not establish a specific role of ANP in chronic stable SIADH. As to the importance of EDNF, dopamine and proximal tubular fluid reabsorption (FCLi) additional work using acute volume changes may demonstrate their participation in the renal sodium handling of SIADH more clearly than our study did.

Aged↗
PubMed1989

Distinct hemodynamic and renal effects of calcitonin gene-related peptide and calcitonin in men.

Cardiovascular and renal actions of human calcitonin gene-related peptide II (or beta) (CGRP) and of human calcitonin (CT) infused intravenously for 1 h each (79 and 263 pmol.kg-1.h-1) have been compared in normal men (n = 10 for CGRP, n = 6 for CT and vehicle alone). CGRP lowered diastolic blood pressure by 26% and increased the heart rate by 35% and raised plasma levels of norepinephrine, epinephrine, and dopamine and renin activity (P less than 0.01). The fractional excretion rates (FE) of sodium and chloride were doubled (P less than 0.05-0.01) in the presence of an unaltered glomerular filtration rate. CT, on the other hand, did not affect the diastolic blood pressure, but the stimulation of diuresis and of the FE of sodium and chloride was more pronounced with CT than with CGRP (P less than 0.01). Moreover, CT lowered serum calcium levels and stimulated urinary adenosine 3',5'-cyclic monophosphate and phosphate excretion (P less than 0.01). In conclusion, the cardiovascular effects of CGRP are contrasted by weaker renal tubular actions of the neuropeptide in relation to CT.

Adult↗