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Biomedical subjects

U von Mandach

Publications and source records attributed to U von Mandach.

6 recordsLinked to original sources
PubMed1989

Pharmacokinetic studies on fenoterol in maternal and cord blood.

Fenoterol plasma concentrations were measured by radioimmunoassay in 38 pregnant women at different stages of preterm labor and in cord blood. Eight women were treated intravenously until delivery with 1.0 to 4 micrograms/min of fenoterol for periods ranging from 27 hours to 27 days; blood samples were taken at the same time as cord blood. In these women the fenoterol concentrations in cord blood ranged from 18 to 53% of the maternal concentrations. In eight women treated intravenously with 1.2 to 4.0 micrograms/min for 2 to 15 days, the infusion was stopped 1.3 to 38 hours before delivery. In these instances the concentrations in cord blood reached as much as 90% of the maternal, meaning that the rate of elimination from fetal plasma is lower than that from maternal plasma. Five women were treated daily with 20 to 30 mg per os for 3 to 17 days (three of these women had also had intravenous treatment before). The ratio of cord to maternal blood concentrations was higher than in women receiving the drug intravenously, the relative times of sampling being the same. The findings suggest that: (1) the placental transfer of fenoterol is higher than that found in previous studies in humans and animals with tritium-labeled substances; (2) the rate of fenoterol elimination from fetal plasma after intravenous and oral long-term therapy is lower than that from maternal plasma; (3) after oral administration, the ratios of fetal to maternal fenoterol concentrations are higher than after intravenous infusion.

Administration, Oral↗
PubMed1987

A simple method for HbF analysis.

Spectrophotometric methods with CO-oxymeters for measurements of carboxyhemoglobin and/or oxygen saturation in human blood include a systematic error depending on the percentage of fetal hemoglobin. It is of clinical importance to estimate the fetal hemoglobin to correct HbCO and SO2 values respectively. The described method is simple and less time consuming than conventional methods like HPLC or electrophoresis. The two measurements of oxy- and carboxyhemoglobin in the same blood sample with different oxygen saturation are needed for the estimation of the HbF and can be performed, including the deoxygenation procedure, in about 40 minutes.

Adult↗
PubMed1987

Peripherally detectable hormones--their relation to the increased uterine activity during standing in pregnant women.

Two-thirds of women in late pregnancy in standing position show marked cyclic accelerations in heart rate with concomitant increase in the uterine activity. As the regulating mechanism of these contractions has not been investigated the aim of the present study is to see if variations in the concentrations of peripheral venous circulating hormones could account for the accelerations of the heart rate and the uterine contractions. In four healthy pregnant women, 25 to 27 years old and in the 33rd-38th weeks of gestation, and in three healthy nonpregnant women, 29 to 30 years old, venous blood was intermittently collected from a cubital vein. The women were investigated in the left lateral as well as in the standing postures. The plasma concentrations of norepinephrine (NE), prostaglandin E2(PGE2), prostaglandin F2 alpha (PGF2 alpha), 6-k-prostaglandin F1 alpha (6-k-PGF1 alpha) thromboxane B2 (TxB2), aldosterone (A), and the plasma renin activity (PRA) were measured by specific and sensitive assays. Significant differences in level and dynamics of the various substances were found between pregnant and nonpregnant subjects. However, no correlation could be found between the fluctuations in the concentration of hormones and heart rate accelerations and the occurrence of uterine contractions, respectively. Local changes of these substances in the uterus may not be reflected in the peripheral venous blood. Therefore our measurements can neither prove nor disprove the hypothesis that these hormonal substances are involved in the regulatory mechanism of uterine contractions occurring in standing.

6-Ketoprostaglandin F1 alpha↗
PubMed1985

[Quantification of the drug-metabolizing enzyme system in liver diseases: a comparison between antipyrine saliva clearance and the aminopyrine breath test].

The metabolic activity of the hepatic cytochrome P450 system was studied in 53 ambulatory subjects. 18 of these were cirrhotics and 23 had non-cirrhotic liver disease, documented by biopsy, serologic, ultrasound or computerized tomography findings, and characterized by quantitative liver function tests, such as galactose elimination capacity and indocyanine green fractional clearance. For comparison, 12 normal control subjects were also included. All subjects were given 10 mg/kg body weight antipyrine and saliva concentrations determined with an HPLC-method at 24 and 48 hours after dosing. Antipyrine saliva clearance (ASC) was calculated according to a two-point method (Cl1), and compared with a one-point method (Cl2) using the 24 h sample only. These subjects also underwent an aminopyrine breath test (ABT), breath samples being collected at regular intervals during 60 minutes following injection of a tracer dose of 1.5 muCi (14C-dimethylamino)antipyrine. Cl1 and Cl2 correlated strongly (r = 0.93). On the basis of smaller variations (particularly in control subjects), better definition of disease severity and convenience and time saving, Cl2 is to be preferred. Comparison of Cl2 with ABT showed that both procedures apparently quantify overlapping enzymatic activities. However, the relationship between Cl2 and ABT values, albeit highly significant (r = 0.72), suggests that only about half of the variables are subject to the same determinant. In addition, a positive intercept of the regression line extrapolated to the Cl2 axis points to quantitatively important extrahepatic breakdown of antipyrine. The results suggest that, in view of the wide variation in normal values (presumably in part influenced by exogenous pollutants), ASC only provides an approximation of hepatic metabolic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Overnight salivary caffeine clearance: a liver function test suitable for routine use.

The feasibility of measuring caffeine clearance from saliva (SCl) was assessed in ambulatory patients with liver disease and in a control group, and the results were compared with quantitative liver function tests. For this purpose, the subjects were given 280 mg caffeine p.o. in decaffeinated coffee powder between noon and 4 p.m., and caffeine concentrations were measured in saliva (using an enzyme immunoassay) before bedtime and upon arising. In the cirrhotics (n = 29), SCl was 0.58 +/- S.D. 0.45 ml per min X kg, thus being reduced to approximately one-third of drug-free, nonsmoking controls (1.53 +/- 0.46, n = 18); although patients with noncirrhotic liver disease showed intermediate values (0.95 +/- 0.47), their reduction in SCl was significant (p less than 0.001). SCl was correlated with indocyanine green fractional clearance, galactose elimination capacity and aminopyrine breath test; however, the closest relationship (Rs = 0.80) was observed with the aminopyrine breath test. It is suggested that the measurement of SCl represents a noninvasive and innocuous procedure for quantifying hepatic microsomal function, and is suitable for routine use. Since a.m. saliva concentrations of caffeine are highly correlated (Rs = -0.94) with SCl, further simplification of the test to a single-point measurement appears possible.

Ambulatory Care↗