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Biomedical subjects

W Rascher

Publications and source records attributed to W Rascher.

At least 199 records · Page 11Linked to original sources
PubMed1988

Role of diuretics, hormonal derangements, and clinical setting of hyponatremia in medical patients.

Because hyponatremia is frequently associated with preceding diuretic treatment and unrestricted fluid intake--conditions which have not been addressed sufficiently in published literature--we studied the pathophysiology and the clinical setting of such hyponatremia in a large group of internal medicine patients. We observed: a) Of an initial 310 patients with chemical hyponatremia only 204 (64%) had an associated plasma hypoosmolality. Since a normal plasma osmolality excludes a disturbance of water metabolism only the 204 patients with hypoosmolar hyponatremia were included in the study. This data shows that plasma osmolality is an essential measurement in any evaluation of hyponatremia. b) In 204 consecutive patients with hypoosmolar hyponatremia the electrolyte disturbance was related to advanced congestive cardiac failure in 25%, decompensated liver cirrhosis in 18%, volume contraction in 28%, syndrome of inappropriate antidiuretic hormone secretion in 19% and renal insufficiency in 4%. c) Plasma vasopressin was measurable in 90% of the 204 patients. It is known that radioimmunoassays to measure vasopressin fail to reliably detect low concentrations of circulating vasopressin (less than 0.5 pg/ml). It may therefore be stated that hypoosmolar hyponatremia was generally characterized by a failure of antidiuretic hormone suppression. d) Mean daily fluid intake of hyponatremic patients was 2.35 +/- 0.15 l. In the presence of stimulated vasopressin this large a fluid intake is bound to worsen the severity of hyponatremia. e) Of 204 patients 126 were treated with diuretics at the time of study. In these patients hyponatremia worsened during such treatments and was associated with evidence of prerenal azotemia. However there were no significant differences between diuretic-treated and -untreated patients with respect to plasma vasopressin stimulation and amount of fluid intake.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1988

Excretion of primary prostanoids and their metabolites during acute volume expansion.

Simultaneous determination of urinary excretion rates of primary unmetabolized prostanoids and their enzymatic metabolites were performed by gas chromatography-mass spectrometry (GC/MS) or tandem mass spectrometry (GC/MS/MS). Changes in kidney function were induced by acute (4 h) volume expansion. Despite marked changes in urine flow, GFR, urinary pH, osmolality, sodium and potassium excretion, only a insignificant or transient rise in the enzymatic prostanoid metabolites (2,3-dinor-6-keto-PGF1 alpha, PGE-M, 2,3-dinor-TxB2 and 11-dehydro-TxB2) was observed. The excretion rates of the primary prostanoids were elevated in parallel with the rise in urine flow: PGE2 rose (p less than 0.05) from 14.2 +/- 4.0 to 86.2 +/- 20.7, PGF2 alpha from 60.0 +/- 4.9 to 119.8 +/- 24.0, 6-keto-PGF2 alpha from 7.2 +/- 1.3 to 51.5 +/- 17.0, and TxB2 from 11.2 +/- 3.3 to 13.6 +/- 3.6 ng/h/1.73 m2 (means +/- SEM) at the maximal urine flow. Except for 6-keto-PGF1 alpha and TxB2, this rise in urinary prostanoid levels was only transient despite a sustained fourfold elevated urine flow. We conclude that urine flow rate acutely affect urine prostanoid excretion rates, however, over a prolonged period of time these effects are not maintained. The present data support the concept that urinary levels of primary prostanoids mainly reflect renal concentrations whereas those of enzymatic metabolites reflect systemic prostanoid activity. From the excretion pattern of TxB2 one can assume that this prostanoid represents renal as well as systemic TxA2 activity.

6-Ketoprostaglandin F1 alpha↗
PubMed1988

Effect of sodium chloride and sodium bicarbonate on blood pressure in stroke-prone spontaneously hypertensive rats.

1. To test the hypothesis that NaCl increases blood pressure, while NaHCO3 does not, we measured the effect of an NaHCO3-containing mineral water on blood pressure in stroke-prone spontaneously hypertensive (SHR-SP) and Wistar-Kyoto (WKY) rats. We compared mineral water with equimolar amounts of NaCl and demineralized drinking water in six groups of 20 rats each over 24 weeks. 2. NaCl consistently increased blood pressure in both SHR-SP and WKY compared with demineralized water, while mineral water did not. 3. We studied the possible role of sodium-regulating hormones. Sodium, potassium-dependent adenosine triphosphatase activity was decreased by NaCl and by age, but not by mineral water. The concentration of atrial natriuretic peptide was greater in SHR-SP, but was not influenced by the two regimens. Components of the renin-angiotensin-aldosterone system and 18-hydroxydeoxycorticosterone tended to decrease with NaCl, but not with mineral water. 4. Plasma pH values in the six groups of rats were not different; however, SHR-SP had consistently lower PCO2 and HCO3- values and higher anion gap values than WKY rats. These values were not influence by the two regimens. 5. NaCl elevates blood pressure in SHR-SP while NaHCO3 does not. The changes in hormones regulating sodium homoeostasis suggest that NaCl induces volume expansion while NaHCO3 does not. The effect may be related to influences on renal sodium reabsorption by chloride and bicarbonate. The possible role of increased proton excretory activity in SHR-SP remains to be determined.

Animals↗
PubMed1988

Atrial natriuretic peptide in volume expansion-induced natriuresis in man.

The role of atrial natriuretic peptide (ANP) in the extracellular volume expansion (ECVE) induced natriuresis was examined in normal man under basal conditions and following dopamine blockage. Hypotonic ECVE was induced by drinking of 20 ml/kg tap water and subsequent intravenous infusion of 2 1 0, 9% saline over a period of 4 hours. This maneuver caused an increase in the plasma concentrations of ANP from 25.8 +/- 3.4 (means +/- SEM) to 59.7 +/- 6.7 fmol/ml. There was a dissociation between ANP response and urinary sodium excretion. A transient rise in glomerular filtration rate (GFR), plasma dopamine and a continuous decrease in plasma renin activity, aldosterone, vasopressin, and noradrenaline were observed. The natriuretic response to ECVE was blunted during dopamine blockade by metoclopramide, but plasma ANP, renin activity, catecholamine and vasopressin levels were not affected. However, plasma aldosterone rose. Our data are compatible with the concept that intrarenal dopamine and raised plasma concentration of ANP contribute to the natriuretic response to ECVE, but these hormonal changes do not completely explain the underlying mechanisms.

Adult↗
PubMed1988

[Clinical relevance of the determination of plasma atrial natriuretic peptide in children with chronic renal failure].

To investigate whether plasma atrial natriuretic peptide (ANP) is a valuable index to detect fluid expansion in children with endstage renal disease, we studied 34 children and adolescents on regular intermittent hemodialysis or on continuous ambulatory peritoneal dialysis (CAPD). In 22 pediatric patients, plasma ANP was markedly elevated prior to hemodialysis and fell to near normal levels after dialysis (109.9 +/- 80.0 to 39.0 +/- 23.1 fmol/ml, means +/- SD). During removal of fluid excess by 1-h sequential ultrafiltration without dialysis in eight adolescents, plasma ANP fell from 123.8 +/- 97.0 to 45.3 +/- 24.6 fmol/ml. Ultrafiltration was followed by 3 h hemodialysis with fluid removal and ANP decreased further to 29.6 +/- 12.1 fmol/ml. In 12 patients on CAPD, plasma ANP was similar to that in 96 healthy control children (29.3 +/- 28.9 vs 23.9 +/- 11.9 fmol/ml) and did not differ from that in 12 children with advanced chronic renal failure (32.6 +/- 20.1 fmol/ml) and seven successfully transplanted children (32.4 +/- 8.5 fmol/ml). Four patients on hemodialysis (post dialysis), one on patients on hemodialysis (post dialysis), one on CAPD and two with advanced chronic renal failure had definitely elevated ANP levels (greater than 56 fmol/ml = greater than 3 SD mean of controls) indicating fluid volume overload. It is concluded that plasma ANP is elevated in children with chronic renal failure due to volume expansion and that measurement of plasma ANP is a sensitive marker to detect fluid overload in these children.

Adolescent↗
PubMed1988

Alterations of vasoconstrictor and sodium-regulating hormone systems in vascularly decompensated liver cirrhosis.

Plasma levels of atrial natriuretic peptide (ANP), aldosterone (PA), vasopressin (AVP), and the plasma renin activity (PRA) were examined in 15 vascularly decompensated patients suffering from liver cirrhosis, before and after administration of albumin and after a subsequent administration of furosemide. The initial ANP level was lower in 9 patients (group "A") and higher in 6 patients (group "B") than in healthy controls (Group "A": 19.5 +/- 3.0 fmol/ml; group "B": 36.7 +/- 3.9 fmol/ml; control: 25.8 +/- 2.4 fmol/ml). The initial PRA (4.4 +/- 1.0 ng AngI/ml/h) and AVP (8.5 +/- 1.5 pg/ml) activity in group "A" increased significantly compared to group "B" (PRA: 0.44 +/- 0.09; AVP: 4.1 +/- 0.5), indicating an intravascular volume depletion in group "A". Albumin infusion raised the urine and sodium excretion and the plasma concentration of ANP in group "A" but lowered in plasma levels of renin and vasopressin. The same parameters were not changed by albumin in group "B". Furosemide equally raised the urine flow rate and sodium excretion in both groups. Plasma ANP level depends on the intravascular volume, and the secondary change in its plasma concentration plays a considerable role in the retention of fluid and electrolytes in patients with cirrhosis. The increased intravascular volume in these patients depletes the fluid and electrolyte retention via the increase in ANP level.

Adult↗
PubMed1987

The syndrome of hypertension and hyperkalaemia with normal glomerular function (Gordon's syndrome). A pathophysiological study.

A 14-year-old boy with the syndrome of hypertension and hyperkalaemia with normal glomerular filtration rate (Gordon's syndrome) is described. The patient's clinical symptoms consisted of periodic paralysis, slight metabolic acidosis of the proximal type and hypercalciuria. Prostaglandin excretion was normal. Infusion of atrial natriuretic peptide had no effect on electrolyte excretion or glomerular function although a normal increase in cyclic guanosine monophosphate was demonstrated in plasma and urine. This lack of sensitivity to atrial natriuretic peptide offers a new pathophysiological concept in this syndrome. Treatment with hydrochlorothiazide was successful in this case.

Adolescent↗
PubMed1987

Congenital nephrogenic diabetes insipidus-vasopressin and prostaglandins in response to treatment with hydrochlorothiazide and indomethacin.

In four boys with congenital nephrogenic diabetes insipidus, plasma arginine-vasopressin (AVP) and urinary excretion of prostaglandins were studied in response to treatment with hydrochlorothiazide and indomethacin. An abnormal relationship between AVP and urine osmolality was demonstrated in all patients. In the first patient, treatment with indomethacin (3 mg/kg per day) resulted in a drop of the insulin and paraminohippurate clearances. In the other three patients urinary excretion of PGE2 was raised, and fell during treatment with hydrochlorothiazide (2 mg/kg per day) and indomethacin (2 mg/kg per day). Urine flow, free water clearance and osmolar clearance decreased during treatment. A combination of both drugs is more effective than hydrochlorothiazide alone and the effect appears to be additive.

Child↗
PubMed1987

Role of prostaglandins in hyperprostaglandin E syndrome and in selected renal tubular disorders.

Renal and systemic prostanoid activity was assessed in various renal tubular disorders, using mass spectrometric determination of urinary excretion rates of primary prostaglandins (PGE2, PGF2 alpha, PGI2, and TXA2) and their systemically produced index metabolites. Only PGE2 levels (normal range: 2.0-16.4 ng/h per 1.73 m2) are elevated in Bartter syndrome (median: 43.4, range: 6.7-166.3), nephrogenic diabetes insipidus (46.2, 12.1-1290), Fanconi syndrome (96.6, 19.3-135.5), and in a complex tubular disorder in premature infants (40.7, 22.3-132.1), for which the term hyperprostaglandin E syndrome has been introduced. In this disorder with a Bartter-syndrome-like tubulopathy, the systemic features of the disease such as fever, diarrhoea and osteopenia with hypercalciuria were associated with increased systemic PGE2 activity. In most patients the urinary excretion rate of the systemic index metabolite of PGE2 (PGE-M) was markedly elevated (1028, 285-4709; normal range: 104-664 ng/h per 1.73 m2). Hypercalciuria per se was associated neither with increased renal nor with systemic PGE2 hyperactivity. Most problems in infants with hyperprostaglandin E syndrome could be controlled by long-term indomethacin treatment in contrast to the moderate and partial effect of this treatment in patients with Fanconi syndrome. Thus increased PGE2 synthesis plays a major role in the pathogenesis of hyperprostaglandin E syndrome, while in Fanconi syndrome PGE2 hyperactivity in the kidney is a secondary event and only aggravates the water and electrolyte wastage.

Bartter Syndrome↗
PubMed1987

Atrial natriuretic peptide and other vasoactive hormones during treatment of severe diabetic ketoacidosis in children.

Plasma concentrations of atrial natriuretic peptide (ANP), arginine vasopressin (AVP), renin activity (PRA), aldosterone, norepinephrine, and cortisol, and renal functions were investigated in nine children with diabetic ketoacidosis. Before therapy, blood glucose concentration was 608.4 +/- 142.2 mg/dL and base excess -21 +/- 1.9 mmol/L. The calculated volume depletion was 2505 +/- 1005 mL/1.73 m2. At the onset of the study, the plasma concentration of ANP (5.3 +/- 1.2 fmol/L) was low, and concentrations of AVP (159 +/- 44 pg/mL), PRA (59 +/- 19 ng angiotensin l/mL/hr), aldosterone (114 +/- 11 ng/dL), norepinephrine (430 +/- 67 pg/mL), and cortisol (33 +/- 2.1 micrograms/dL) were markedly elevated. Fluid replacement raised plasma ANP concentration, which reached physiologic levels on the first day of therapy. PRA, aldosterone, norepinephrine, and cortisol also normalized during the first 24 hours of therapy, whereas AVP remained above the physiologic range at 20.4 +/- 6.8 pg/mL on the third day. Our data indicate that in diabetic ketoacidosis, volume depletion, enhanced sodium excretion, and hyponatremia activated vasoconstrictor and sodium-retaining hormone systems and that secretion of the natriuretic and vasodilator hormone ANP is suppressed. All of these hormonal alterations seem directed at maintaining adequate fluid volume and sodium homeostasis.

Adolescent↗
PubMed1987

Atrial natriuretic peptide and other vasoactive hormones in nephrotic syndrome.

Plasma levels of atrial natriuretic peptide (ANP), arginine vasopressin (AVP), renin activity (PRA), aldosterone (PA), catecholamines and urinary prostaglandins (PG), as well as renal function were measured in children in the edematous state of the nephrotic syndrome before and after infusion of human serum albumin. Before albumin infusion, plasma levels of AVP, PRA, PA and noradrenaline (NA) and urinary excretion of PGE2, PGE-Met, PGF2 alpha were elevated. The mean value of plasma ANP was in the normal range. Albumin infusion produced a 36% increase in the calculated plasma volume. It was associated with a fivefold rise in the plasma level of ANP (31.6 +/- 22.6 vs. 151.4 +/- 52 fmol/ml mean, SD), and a significant fall in the levels of PRA, AVP, PA, and NA. Similarly, urinary concentration of PGE2, PGE-Met and PGF2 alpha fell. Urine flow, GFR, UNaV, FENa, and COsm increased significantly, while CH2O remained unchanged. The diuresis, natriuresis and GFR correlated with the level of plasma ANP, while urinary sodium excretion did not correlate with PA or NA levels. These findings suggest that ANP plays an important role in albumin induced natriuresis in children with nephrotic syndrome.

Adolescent↗
PubMed1987

Pathogenesis of clinical hyponatremia: observations of vasopressin and fluid intake in 100 hyponatremic medical patients.

The pathogenesis of hyponatremia remains debated; therefore, we determined the roles of plasma vasopressin, fluid intake and renal free water excretion in hyponatremic medical patients. We evaluated 100 consecutive hypo-osmolar hyponatremic patients (PNa = 127 +/- 0.7 mM l-1) in a prospective manner. We observed: hyponatremia was often found in association with advanced congestive cardiac failure (twenty-five of 100 patients), liver cirrhosis (16%) and primary volume contraction (29%). There was a 17% in-hospital mortality of hyponatremic patients. This was primarily related to the severity of underlying illnesses rather than to hyponatremia per se. The most consistently observed laboratory finding of hyponatremia was non-osmotic vasopressin stimulation; mean observed PADH was 4.7 +/- 0.7 pg ml-1 and vasopressin was detectable by radioimmunoassay (RIA) in 91% of all patients. In addition to vasopressin stimulation we also found evidence of advanced 'circulatory underfilling' in most hyponatremic patients. Mean urinary osmolality was hypertonic to plasma (441 +/- 17.4 m0sm kg H2O-1). This applied to patients with hyponatremic cardiac failure, liver cirrhosis and volume contraction. Almost all of these patients received high ceiling diuretics. (v) Spontaneous mean daily fluid intake was 2.4 +/- 0.2 l. In summary, our findings suggest that disturbances of vasopressin, fluid intake and renal free water excretion co-operate in the pathogenesis of hyponatremia. In clinical states of advanced circulatory underfilling the occurrence of hyponatremia indicates a poor prognosis of the patient.

Aged↗