Increased concentration of circulating atrial natriuretic peptide during normal pregnancy.

Atrial natriuretic peptide (ANP) is a recently discovered cardiac hormone involved in blood-volume homeostasis. Known stimulating factors for ANP release are rise in atrial pressures or atrial distension, suggesting that blood volume regulates ANP release. This study was undertaken to test the hypothesis that plasma levels of ANP are high and increase during normal pregnancy secondary to the expanding plasma volume. In a cross-sectional study plasma concentrations of ANP were measured in 99 normal pregnant women at different gestational ages and compared with the values found in an age-matched non-pregnant control group. Mean plasma ANP was already significantly increased in the first trimester as opposed to the non-pregnant women, but despite a continuously expanded plasma volume there was no further increase during pregnancy. Our findings suggest that other factors must interact with plasma volume in regulating plasma ANP during pregnancy.

Atrial natriuretic peptide concentrations in pre-eclampsia.

The concentration of plasma immunoreactive atrial natriuretic peptide is positively associated with right atrial and pulmonary capillary wedge pressure, suggesting that blood volume and hence atrial pressure govern its release. Expansion of plasma volume is a central physiological adjustment in normal pregnancy. Conversely, pregnancies complicated by pre-eclampsia are associated with a reduction in plasma volume and central venous pressure. A study was therefore undertaken to test the hypothesis that plasma atrial natriuretic peptide concentrations are low in pre-eclampsia owing to deficient secretion. Concentrations of the peptide were measured by a specific radioimmunoassay. The mean plasma immunoreactive atrial natriuretic peptide concentration in healthy pregnant women (n = 22; third trimester) was higher (56 (1 SD 29) ng/l) than in 25 young, non-pregnant controls (37 (19) ng/l). Concentrations in patients suffering from mild pre-eclampsia (n = 9) were higher (127 (60) ng/l) than in normal pregnant women, and in patients with severe pre-eclampsia (n = 6) concentrations were higher still (392 (225) ng/l). Despite failure of plasma volume expansion and low central venous and pulmonary capillary wedge pressures in pre-eclampsia this condition is associated with greatly increased plasma concentrations of plasma immunoreactive atrial natriuretic peptide, which increase still further with the severity of the disease. These findings are clear evidence that atrial pressure may not be the principal determinant of the release of the natriuretic peptide in pre-eclampsia.

The effects of vaginal repair on anterior bladder suspension defects. A radiological and clinical evaluation.

In 22 patients with anterior bladder suspension defect as judged by colpocysto-urethrography (CCU) a vaginal repair was undertaken. In 14 patients urinary stress or urge and stress incontinence was the indication for operation, and in 8, genital prolapse. At follow-up more than 6 months postoperatively the CCU was repeated and a clinical evaluation undertaken. A normalization of the CCU was obtained in only 6 patients and 10 showed a less severe suspension defect. Nine of 14 patients were cured of incontinence. Only 3 of these had a normal follow-up CCU. Improvement of bladder suspension defect was not the sole responsible factor for postoperative continence. Urinary incontinence developed postoperatively in 2 of 8 patients operated on solely because of symptomatic genital prolapse. Very high cure rates for urinary incontinence have been reported following a colposuspension operation. A vaginal repair is not recommended as first-choice operation in incontinent females with anterior bladder suspension defects, if a CCU may be undertaken and the colposuspension technique is mastered.

A urodynamic study of cauda equina syndrome due to lumbar disc herniation.

Among 1,972 patients operated upon because of lumbar disc herniation in a 7-year period (1971-1978), cauda equina syndrome was diagnosed in 26 patients. 22 patients had follow-ups 4-72 months postoperatively (average 37 months). At follow-up half of the patients had histories of normal micturition and only 6 patients made serious micturition complaints. One third were free from lumbar or sciatic pain, two thirds complained of distressing pain and neurological symptoms. The urodynamic investigation revealed complete bladder emptying in all but 1 patient. In half of the patients normal detrusor contraction was demonstrated, while one third of the patients voided by straining only. Preoperative micturition symptoms exceeded 2 days in almost all patients voiding by straining. This finding indicates a connection between early diagnosis and treatment, and the degree of detrusor damage.