Biomedical subjects
Publications and source records attributed to F Fuchs.
With six different groups of pharmacologic agents that potentially can inhibit undesirable uterine contractions, prevention of premature births should be increasingly successful. The rationale for the use of each of these agents and their advantages and disadvantages are discussed.
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The prostaglandin synthetase inhibitor ibuprofen was evaluated for relief of severe primary dysmenorrhea in a controlled, double-blind, cross-over study in seven patients for a total of 23 menstrual cycles. In eight untreated cycles, the amount of prostaglandin (PG) in the menstrual fluid was higher than in nondysmenorrheic subjects. There was good to excellent relief of dysmenorrhea in seven ibuprofen-treated cycles, which was associated with a threefold to fourfold reduction in menstrual PG released. When a placebo was given in five cycles, only poor or minimal relief of dysmenorrhea was obtained and the menstrual PG released was similar to that in control cycles. In individual patients, there was a remarkable correlation between the severity of menstrual pain as assessed daily by the patient and the level of menstrual PG released during the corresponding period. The effect of ibuprofen therapy on menstrual fluid volume was inconsistent. The study shows that in severe primary dysmenorrhea there is increased release of PG in the menstrual fluid; this can be effectively suppressed with ibuprofen, which provides excellent relief from the symptoms of dysmenorrhea.
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Variation of pH over the range 6.2--7.4 had no effect on the Ca2+ titration curve of glycerinated rabbit psoas muscle fibers. Thus the effect of H+ on muscle contraction is not due to a simple H+-Ca2+ competition for binding sites.
Oxytocin (OT) was measured by a specific and sensitive RIA in plasma and amniotic fluid throughout pregnancy. OT was detectable in 84.5% of 362 maternal plasma samples and showed a slow and fluctuating increase towards term with a significant sharp peak at 39 weeks of gestation. There was a highly significant correlation between mean plasma OT and the week of gestation (r = 0.5419, P less than 0.005). The minute to minute variability in plasma OT during pregnancy and labor in 7 subjects showed episodic release of OT with two or three spurts per 10 min, with the amplitude of the spurts being greater during labor. Serial maternal plasma OT throughout pregnancy in 10 patients revealed good concentrations of OT (greater than 10 pg/ml) in patients who subsequently had spontaneous labor and no intrapartum uterine dysfunction. Poor (less than 10 pg/ml) or undetectable OT levels were found in patients who subsequently developed intrapartum uterine dysfunction which necessitated cesarean section. OT was detectable in 89.7% or 87 amniotic fluid samples, with a mean +/- SE of 7.8 +/- 3.6 pg/ml at 14--15 weeks, 43.9 +/- 14.7 pg/ml at 40 weeks, and 30.8 +/- 10.5 pg/ml at 41--42 weeks. The significance of these findings is discussed in relation to the role and origin of OT in pregnancy and parturition.
Oxytocin was determined by radioimmunoassay in pregnant baboons throughout gestation, in the foetus at caesarean section, and after oxytocin infusion into the mother and foetus. Serial maternal plasma oxytocin in 6 baboons during pregnancy showed a significant correlation between the gestational age and maternal plasma oxytocin concentrations with a correlation coefficient of r = 0.3185 and P less than 0.005. Seventy-one out of 75 plasma samples (94.7%) during pregnancy had detectable levels of oxytocin. Uterine vein plasma had higher oxytocin concentrations than maternal plasma and amniotic fluid (18.6 +/- 4.6 pg/ml; mean +/0 SE) but lower than umbilical, jugular vein and cardiac blood from the foetus. Foetal pituitary gland contained 5.4--26.1 micrograms oxytocin/g. Regular uterine contractions were established with iv oxytocin of 4--20 mU/min and the plasma oxytocin measured showed a significant correlation with the uterine activity achieved (r = 0.64, P less than 0.001). The disappearance of plasma oxytocin at 179 days gestation gave an apparent half-life of 1.1 and 1.7 min in 2 baboons with a late half-life of 9.9 and 17.3 min, respectively. In one baboon at 171 days gestation, the apparent half-life of oxytocin was 9.9 min. The metabolic clearance rates were calculated to be 3.1, 3.2 and 11.7 ml/kg/min, respectively. The production rates were 97, 74, 390 pg/kg/min, respectively. Oxytocin injected into the umbilical vessel near term showed an increase in oxytocin concentration in maternal and uterine vein plasma and amniotic fluid, suggesting that oxytocin can cross the placenta from the foetal to the maternal side. Our findings indicate that in the baboon (1) oxytocin is present throughout pregnancy, (2) uterine activity can be correlated with plasma oxytocin during oxytocin infusion, (3) foetal circulation has higher oxytocin concentration than maternal blood and (4) oxytocin probably can cross the placenta from the foetus to the mother.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
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The formation of rigor complexes between the thick and thin filaments of glycerinated rabbit psoas muscle fibers causes the fibers to bind more calcium at any given level of free calcium. I studied the maximum amount of calcium bound as a function of filament overlap under rigor conditions. Fibers stretched to zero filament overlap (sarcomere length greater than 3.8 micron) bound exactly 75% as much calcium as fibers with maximum overlap. Between these extremes a linear relationship was found between maximum bound calcium and the length of the overlap zone. The results support the hypothesis that in the intact filament lattice one of the four calcium-binding sites of troponin depends for its existence on attachment between myosin and actin. In addition, the linear relation between maximum bound calcium and filament overlap is consistent with the assumption that the cooperative effect of rigor complex formation on calcium binding is limited to the binding site in the immediate vicinity of the rigor complex.
In spite of the rapid development of amniocentesis for genetic diagnosis, it is still only a small fraction of the mothers at risk who are having the procedure performed. The medical and public health problems associated with genetic amniocentesis are discussed on the basis of the experience gathered in a major medical center.
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Fetal oxytocin contribution to the mother during spontaneous labor was investigated using a specific and sensitive radioimmunoassay to measure oxytocin in blood, amniotic fluid, and urine. In 26 subjects with spontaneous labor and vaginal delivery (Group I) and 18 subjects with cesarean section after labor (Group II), umbilical arterial plasma (UA) oxytocin concentrations were significantly higher than umbilical venous plasma (UV) ocytocin concentrations. With elective cesarean section (Group III), UA oxytocin concentration was 29.8 +/- 7.5 pg/ml and UV oxytocin concentration was 16.1 +/- 5.9 pg/ml (n = 14). In contrast, the mean UV oxytocin concentration was higher than the mean UA oxytocin concentration, when oxytocin was given to the mothen concentration in Groups I and II was significantly higher than in Group III. Amniotic fluid oxytocin concentrations in Group I and II patients were higher than in Group III. Oxytocin was also present in fetal urine. The findings indicate that during spontaneous labor, oxytocin is produced by the fetus and flows toward the maternal circulation.
The effect of Beta-Sitosterol (Sitosterin Delalande) on plasma lipids in 20 pretreated patients with type IIa and IIb familial hyperlipoproteinemia is reported. 6-18 g of the drug were given for a time of two to twelve months. In 11 patients the plasma cholesterol level decreased between 10 and 30%. Since Beta-Sitosterol has no effect on plasma triglycerides, an additional hypertriglyceridemia must be taken care of and treated if necessary. Beta-Sitosterol can be called an effective substance in the treatment of hypercholesterinemia. In addition the diet cure becomes easier.
A double isotope technique and EGTA buffers were used to measure the binding of Ca2+ to rabbit psoas muscle fibers extracted with detergent and glycerol. These experiments were designed to test the effect of rigor complex formation, determined by the degree of filament overlap, on the properties of the Ca2+-binding sites in the intact filament lattice. In the presence of 5 mM MgCl2 (no ATP), reduction of filament overlap was associated with a reduced binding of Ca2+ over the entire range of free Ca2+ concentrations (5.10(-8)-2.10(-5) M). With maximum filament overlap (sarcomere length 2.1-2.2 micrometer) the maximum bound Ca2+ was equivalent to 4 mol Ca2+/mol troponin and there was significant positive interaction between binding sites, as shown by Scatchard and Hill plots. With no filament overlap (sarcomere length 3.8-4.4 micrometer) the maximum bound Ca2+ was equivalent to 3 mumole Ca2+/mol troponin and graphical analysis indicated a single class of non-interacting sites. The data provide evidence that when cross-bridge attachments between actin and myosin filaments are formed not only does an additional Ca2+ binding site appear, but cooperative properties are imposed upon the binding sites.