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Biomedical subjects

M Madsen

Publications and source records attributed to M Madsen.

At least 181 records · Page 10Linked to original sources
PubMed1987

Exaggerated natriuretic response to isotonic volume expansion in hypertensive renal transplant recipients: evaluation of proximal and distal tubular reabsorption by simultaneous determination of renal plasma clearance of lithium and 51Cr-EDTA.

In fourteen hypertensive and fourteen normotensive renal transplant recipients, and in a group of thirteen healthy controls, changes in natriuresis, glomerular filtration rate (GFR), and tubular reabsorption of sodium were determined in relation to intravenous infusion of 2 mmol isotonic sodium chloride per kg body weight. An exaggerated natriuresis was demonstrated in the hypertensive renal transplant recipients. This new finding indicates that the augmented natriuresis following plasma volume expansion, which is a characteristic finding in subjects with arterial hypertension, is not mediated by the renal nerves. Investigation of the tubular reabsorption rates of sodium by simultaneous determination of the renal clearance of 51Cr-EDTA and lithium showed that in the hypertensives the changes in tubular handling of sodium were different from those registered in the normotensive subjects. The increased sodium excretion in the hypertensive renal transplant recipients was caused by an increased output of sodium from the proximal tubules which was not fully compensated for by an increased distal reabsorption. Whether this increased delivery of sodium to the distal segments was caused by changes in GFR or in the proximal tubular reabsorption of sodium could not be clarified in the present study and warrants further investigations.

Absorption↗
PubMed1987

Effect of water coagulation by seeds of Moringa oleifera on bacterial concentrations.

The effects of a Sudanese water purification method traditionally used in Sudan to treat turbid waters were studied with respect to turbidity reduction and removal of faecal indicator bacteria as well as selected enteric bacterial pathogens. Water treatment was performed at 30 degrees C with Moringa oleifera seed material as a coagulant, and the technique employed corresponded closely to that used to clarify turbid water in Sudanese villages. A turbidity reduction of 80.0-99.5% paralleled by a primary bacterial reduction of 1-4 log units (90.00-99.99%) was obtained within the first 1 to 2 h of treatment, the bacteria being concentrated in the coagulated sediment. During the 24 h observation period a secondary bacterial increase due to regrowth in the supernatant water was consistently observed for Salmonella typhimurium and Shigella sonnei, in some cases for Escherichia coli, but not for Vibrio cholerae, Streptococcus faecalis and Clostridium perfringens. The potential of the method when compared with some alternative for the improvement of rural drinking water supplies is discussed.

Disinfection↗
PubMed1986

Randomised controlled trial of genetic amniocentesis in 4606 low-risk women.

Outcome of pregnancy after amniocentesis was studied in a randomised controlled trial of 4606 women, age-range 25-34 years, without known risk of genetic disease. Spontaneous abortion rate was 1.7% in the study group after amniocentesis and 0.7% in the control group after ultrasound (relative risk 2.3). In the study group, increased levels of maternal serum alpha-fetoprotein before amniocentesis, perforation of the placenta during amniocentesis, and withdrawal of discoloured amniotic fluid were associated with an increased risk of spontaneous abortion. In the first six weeks after amniocentesis/ultrasound scan, amniotic fluid leakage occurred more often in the study group but there was no difference in the rate of vaginal bleeding. Frequency of postural malformations in the infants in the two groups was the same. In the study group, respiratory distress syndrome was diagnosed more often (relative risk 2.1) and more babies were treated for pneumonia (relative risk 2.5).

Abortion, Spontaneous↗
PubMed1986

Abnormal vasopressin and aldosterone response to furosemide in essential hypertension.

Plasma concentrations of arginine vasopressin (AVP), angiotensin II (AII), aldosterone (Aldo), urinary output (V), osmolar clearance (Cosm), free water clearance (CH2O), fractional excretions of sodium (FENa) and potassium (FEK), urinary sodium excretion rate (U-Na) and serum potassium (S-K) were determined in 9 patients with essential hypertension (group I) and 13 normotensive healthy control subjects (group II) before and three times during the first 4 hours after an intravenous injection of 40 mg of furosemide. AVP, AII, Aldo, V, Cosm, FENa, FEK and U-Na increased in both groups. However, the elevation in AVP was significantly more pronounced and the rate of increase in Aldo was significantly slower in group I than in group II. There were no significant differences in AII, V, Cosm, CH2O, FENa, FEK and U-Na between the groups. S-K was significantly reduced only in group I. AVP and AII were not significantly correlated to each other or to blood pressure. It is suggested that the responsiveness of the renal tubules to AVP is reduced in essential hypertension and that the larger increase in AVP might be a compensatory phenomenon. The slower increase in Aldo in essential hypertension could be attributed to the reduction in S-K.

Adult↗
PubMed1986

Angiotensin II, aldosterone and arginine vasopressin in plasma in congestive heart failure.

Angiotensin II (AII), aldosterone (Aldo) and arginine vasopressin (AVP) in plasma were determined during basal conditions in seventeen patients with congestive heart failure and in seventeen control subjects. The same parameters were measured before and 1, 2 and 3 h after an oral water load of 20 ml (kg body weight)-1 together with urine volume (V) and free water clearance (CH2O) in seven patients with congestive heart failure and in seven control subjects. AII, Aldo and AVP were significantly higher in heart failure than in control subjects (AII:81 and 12 pmol l(-1) (medians), P less than 0.01; Aldo: 411 and 103 pmol l(-1), P less than 0.01; AVP: 5.3 and 2.0 pmol l)-1), P less than 0.01). AVP was positively correlated to Aldo in both heart failure (p = 0.593, n = 17, P less than 0.02) and control subjects (p = 0.511, n = 17, P less than 0.05), but in neither of the groups to AII. V and CH2O were significantly lower in heart failure when compared to control subjects (maximum increase in CH2O 3.55 and 5.86 ml min-1, P less than 0.02), but did not correlate directly with either A II, Aldo or AVP. Creatinine clearance was reduced in heart failure. It is concluded that the activity of both the renin-angiotensin-aldosterone system and the osmoregulatory system is enhanced in congestive heart failure, presumably as a compensatory phenomenon in order to maintain arterial blood pressure. It is suggested that the decrease in free water clearance may be attributed to both an elevated level of vasopressin and a reduced glomerular filtration rate.

Aged↗
PubMed1986

Effect of exercise on plasma concentrations of arginine vasopressin, angiotensin II and aldosterone in hypertensive and normotensive renal transplant recipients.

Plasma concentrations of angiotensin II (A II), aldosterone (Aldo) and arginine vasopressin (AVP), and serum osmolality (Sosm) were determined before and after gradually increasing exercise loads on a bicycle ergometer in 10 hypertensive (group I) and 10 normotensive renal transplant recipients (group II), and in 15 healthy control subjects (group III). Working capacity was reduced in groups I and II. The A II, Aldo, AVP, Sosm increased in all groups after exercise. The A II was higher in group I than II and the percentage changes were significantly lower in groups I and II than in group III. There were no significant differences in Aldo between the groups either before or after exercise. The AVP was the same in groups I and II, and AVP in these groups was higher than in group III. The Sosm and AVP were significantly correlated in all groups. Neither A II, Aldo nor AVP were significantly correlated to systolic blood pressure (BP). Alterations in AVP, but not in A II or Aldo, were correlated to the degree of exercise load. It can be concluded that the renin-angiotensin-aldosterone system and the osmoregulatory system are stimulated during exercise in renal transplant recipients. The A II is elevated in post-renal transplant hypertension, but the responsiveness is reduced in both hypertensive and normotensive recipients. The alterations in AVP are probably secondary to changes in Sosm, and the higher AVP levels in recipients could be due to a decreased responsiveness of the renal tubules to AVP. Our findings are in good agreement with the hypothesis that hypertension after renal transplantation is angiotensin II-dependent.

Adult↗
PubMed1986

Post-renal-transplant hypertension. Urine volume, free water clearance and plasma concentrations of arginine vasopressin, angiotensin II and aldosterone before and after oral water loading in hypertensive and normotensive renal transplant recipients.

Urine volume (V), free water clearance (CH2O) and plasma concentrations of arginine vasopressin (AVP), angiotensin II (A II) and aldosterone (Aldo) were determined before and three times during the first 5 h after an oral water load of 20 ml/kg body wt in 19 patients with post-renal-transplant hypertension (group I), in 13 normotensive renal transplant recipients (group II) and in 20 control subjects (group III). Both V and CH2O increased significantly in all groups, but considerably less in groups I and II than in group III. When CH2O was related to glomerular filtration rate no differences existed between patients and control subjects. Basal AVP was the same in groups I (3.3 pmol/l, median) and II (3.0 pmol/l), but significantly (p less than 0.01) higher than in group III (1.9 pmol/l). Basal A II was significantly (p less than 0.01) elevated in group I (18 pmol/l) when compared to both groups II (10 pmol/l) and III (11 pmol/l), and the level was independent of the presence of native kidneys. Basal Aldo was the same in all groups. During loading, AVP was reduced in all groups, A II was almost unchanged, and Aldo was increased in groups I and II and reduced in group III depending on alterations in serum potassium. Thus urinary diluting ability is reduced in renal transplant recipients due to a reduced glomerular filtration rate. The enhanced A II in hypertensive renal transplant recipients gives further evidence for the point of view that hypertension is angiotensin-dependent in most of these patients.

Adult↗
PubMed1986

Impaired renal water excretion in early hepatic cirrhosis. Lack of relationship between renal water excretion and plasma levels of arginine vasopressin, angiotensin II, and aldosterone after water loading.

An oral water load of 20 ml per kg body weight was given to 9 patients with hepatic cirrhosis and 11 healthy controls. Urinary output, free water clearance, and plasma concentrations of arginine vasopressin, angiotensin II and aldosterone were determined before and three times during the first 4 h after loading. In the cirrhotic patients urinary output was significantly lower after loading than in the control subjects, mainly because of a lower free water clearance, and, in contrast to the healthy controls, the cirrhotic patients did not have natriuresis after water loading. No differences were found between patients and controls in arginine vasopressin, angiotensin II, aldosterone, or creatinine clearance. It is concluded that patients with well-compensated cirrhosis of the liver have an impaired ability to excrete sodium and water. This phenomenon does not seem to be due to increased arginine vasopressin secretion, activation of the renin-angiotensin-aldosterone system, or a decreased glomerular filtration rate.

Adult↗
PubMed1986

"The low T3 syndrome" and impaired thyroid protein synthesis in experimental trauma.

The thyroid response was evaluated in the present trauma model. Trauma of varying severity was studied in 3 groups of anesthetized pigs. The animals were exposed to preparative surgery alone (n = 6) or followed by a standardized missile trauma to a hind leg (n = 10) or to the abdomen (n = 8). Post-trauma observation for 24-48 hours under continuous anesthesia included measurements of circulating T4, T3 and rT3. The serum concentrations of T4 and T3 fell significantly in all groups, the fall being exponential in the missile trauma groups. The reductions were greatest in the most severely injured group (abdominal trauma) and least in the group with preparative surgery only. The nadir of T4 concentration was reached at 24 hours in all groups. The T3 nadir occurred at 12 hours in the abdominal trauma group and at 24 hours in the groups with hind-leg trauma and preparative surgery. The rT3 concentration was significantly increased in the missile trauma groups. Thyroid protein synthesis was analysed in vitro by incubating thyroid tissue from pigs with missile trauma (n = 9) or with preparative surgery (n = 6). The 3H-leucine incorporation into the soluble thyroid proteins, measured as DPM/DNA, was 35% lower after missile trauma than after preparative surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗