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Biomedical subjects

D M Strickland

Publications and source records attributed to D M Strickland.

At least 37 records · Page 2Linked to original sources
PubMed1985

Umbilical cord pH, PCO2, and bicarbonate following uncomplicated term vaginal deliveries.

Normal values for umbilical arterial and venous pH, PCO2, PO2, and bicarbonate must be known before these parameters can be used for assistance in clinical decisions. We evaluated the cord blood from 146 infants born after uncomplicated labor and vaginal deliveries at 37 to 42 weeks' gestation. All infants had a normal baseline fetal heart rate and normal beat-to-beat variability for at least 10 minutes preceding expulsion. The cord blood of infants born to women with pregnancy complications such as diabetes mellitus, preeclampsia, twins, meconium-stained amniotic fluid, or fetal growth retardation was not included. Mean umbilical arterial values +/- 1 SD for the parameters studied were: pH, 7.28 +/- 0.05; PCO2, 49.2 +/- 8.4 mm Hg; PO2, 18.0 +/- 6.2 mm Hg; bicarbonate, 22.3 +/- 2.5 mEq/L. Umbilical venous values were: pH, 7.35 +/- 0.05; PCO2, 38.2 +/- 5.6 mm Hg; PO2, 29.2 +/- 5.9 mm Hg; bicarbonate, 20.4 +/- 4.1 mEq/L.

Bicarbonates↗
PubMed1985

Endogenous stimulant of prostaglandin endoperoxide synthase activity in human amniotic fluid.

In this study we describe the discovery and characterization of a substance in human amniotic fluid that stimulates prostaglandin biosynthesis by a microsome-enriched preparation of bovine seminal vesicles. The stimulatory activity is not retained substantially upon anisotropic ultrafiltration through a filter with a molecular weight exclusion limit of 500. Stimulation of prostaglandin biosynthesis by this substance is time- and concentration-dependent; maximal stimulation of approx. 200% being observed within 20 min of commencing incubation with 1 ml-equivalent of stimulant fraction. Stimulatory activity is demonstrable both in the presence of reduced glutathione (1.3 mM) and L-tryptophan (20 mM), either separately or combined, and in the presence of exogenous arachidonic acid (5-120 microM). In the absence of added cofactors, the stimulatory substance increases the rates of biosynthesis of prostaglandin E2 and prostaglandin F2 alpha to equal extents. The amount of stimulatory substance added to incubations is correlated positively with increased oxygen consumption during incubations. The stimulatory substance is stable to heating at 100 degrees C for 10 min but is inactivated substantially (to less than 20% of original activity) by treatment with pronase. It is concluded that human amniotic fluid contains a substance of relatively low molecular weight, which is proteinaceous in character, that stimulates prostaglandin endoperoxide synthase activity.

Amniotic Fluid↗
PubMed1985

Prostaglandin biosynthesis stimulatory and inhibitory substances in human amniotic fluid during pregnancy and labor.

Human amniotic fluid has been separated into two fractions; one fraction inhibits prostaglandin biosynthesis and the other fraction is stimulatory. The activity of the stimulatory fraction increased with increasing gestational age and was greater still during labor. The activity of the inhibitory fraction decreased with increasing gestational age and was smaller still during labor. We speculate that these changes may play a significant role in parturition.

Amniotic Fluid↗
PubMed1984

Plasma prostaglandins during the intravenous infusion of angiotensin II in pregnant women.

The possible relation between prostaglandin production and the sensitivity of pregnant women with pregnancy-induced hypertension to the pressor effects of angiotensin II was investigated. Plasma prostaglandin levels were determined in four groups of women before, during, and after intravenous infusion of angiotensin II. Concentrations of the stable metabolites of prostaglandin E2, prostaglandin F2 alpha, and prostaglandin I2 (prostacyclin) were quantified by specific radioimmunoassays in the plasma of nonpregnant women, women pregnant in the late third trimester, and women pregnant in the late third trimester with either pregnancy-induced or chronic hypertension. Plasma prostaglandin concentrations did not change significantly during angiotensin II infusion in any of the four groups of women. Levels of the prostacyclin metabolite, however, were significantly higher in the hypertensive pregnant women than in the normotensive pregnant women.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Umbilical cord pH and PCO2: effect of interval from delivery to determination.

Determinations of umbilical blood pH and PCO2 can be useful for correlating intrapartum fetal heart rate patterns, intrapartum samples of scalp blood, and Apgar scores, for the retrospective evaluation of the management of a particular labor. Occasionally, such data can indicate and clarify needed resuscitative measures and intensive neonatal observation. Cumbersome techniques have been described for the handling of specimens of cord blood to ensure an accurate determination. This study was performed to determine the effect on cord blood pH and PCO2 of room temperature and time from delivery. One hundred five cord venous or arterial determinations had a linear pH decrease versus time at room temperature. The regression slope was -3.66 X 10(-4) per minute with a standard deviation of 1.37 X 10(-2). The PCO2 showed only a slight increase with time at room temperature, although the scatter was high, with a standard deviation of 3.8 torr. The conclusion is that samples of cord blood drawn for determination of pH and PCO2 can be kept at room temperature in plastic syringes for up to 30 minutes without significant alteration in these values, i.e., pH decrease no greater than 0.04 unit (p less than 0.05).

Apgar Score↗
PubMed1984

Effect of radiation on prostaglandin production by human bowel in vitro.

The effect of gamma irradiation on the production of prostaglandins by human colon was investigated. Squares of tissue in organ culture dishes were irradiated with 500, 1000, or 2500 rad in single applications. Tissues that were not irradiated served as controls. After treatment the tissues were superfused and prostaglandin concentrations in the effluent fluid were determined. The rates of production of prostaglandins E2 and F2 alpha by irradiated tissues were significantly lower (p less than 0.05) than those of nonirradiated tissues. Neither the release of lactate dehydrogenase nor the rate of production of 13,14-dihydro-15-keto-prostaglandin F2 alpha were increased in the irradiated samples, suggesting that neither decreased cell viability nor increased prostaglandin metabolism accounted for the decreased prostaglandin production rates. We conclude that irradiation of the human colon in vitro results in an acute inhibition of prostaglandin synthesis. The cytoprotective nature of prostaglandins is discussed with regard to the possible pathophysiological significance of these findings.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Amylase and isoamylase activities in serum of pregnant women.

The data previously reported for serum amylase activity in the blood of pregnant women are conflicting with respect to normal values and the relationship of activity to duration of pregnancy. By use of a DuPont Automatic Clinical Analyzer, amylase activity in serum from the blood of 413 asymptomatic healthy women who were six to 40 weeks pregnant was determined. Samples with amylase activity greater than 100 IU/L were tested for pancreatic and salivary isoenzymes. In every case except one, the isoenzyme levels were normal. In the blood of all women, except this one, the serum amylase activity was less than 150 IU/L and mean serum amylase activity did not correlate with gestational duration. Amylase activities at all gestational ages did not differ from the activity in serum obtained from the blood of women six weeks post partum. The authors conclude that 1) serum amylase levels may be as high as 150 IU/L in the blood of normal pregnant women; 2) serum amylase activities vary widely among pregnant women, but not in a manner related to the stage of gestation; and 3) pregnancy does not cause elevation of serum amylase isoenzyme activity.

Amylases↗
PubMed1984

Significance of brown and/or green amniotic fluid at the time of second trimester genetic amniocentesis.

During a two-year period, 83 discolored fluids (77 green, six brown) were obtained during genetic amniocenteses of 1227 patients. When compared with case-matched control subjects, those patients with discolored fluid had no differences in the incidence of spontaneous abortions, abnormal fetal karyotypes, infant abnormalities, occurrence of preterm labor, or requirement for delivery by cesarean section. The only statistically significant difference between control and test patients was that one in 83 versus 32 of 83 reported bleeding before amniocentesis (P less than .001). Both green and brown fluids had spectrophotometric peaks at 400 to 408 nm, similar to that reported for meconium. However, discolored fluid had measurable free hemoglobin, whereas meconium-stained fluid from term gestations did not, suggestive of an in utero hemorrhage. Further, when fetal blood, in concentrations calculated to yield a hemoglobin content similar to those measured in the discolored fluids, was incubated in amniotic fluid the spectrophotometric peak and absorbance units at 400 to 408 nm were similar to those for the discolored fluids. These observations are supportive of the hypothesis that blood breakdown products from an episode of intrauterine bleeding are responsible for the discolored fluid. Discolored amniotic fluid during second trimester, as an isolated finding, does not prognosticate a poor pregnancy outcome.

Amniocentesis↗
PubMed1984

Prostaglandin synthase inhibitory activity in plasma of women with dysmenorrhea.

Prostaglandins have been implicated in the etiology of dysmenorrhea, and plasma levels of prostaglandin F metabolite are increased in women during dysmenorrhea episodes. We determined the prostaglandin synthase inhibitory activity of plasma obtained from the blood of women who experience moderate to severe dysmenorrhea. Blood was obtained at the onset of dysmenorrhea ("symptomatic") and during the late follicular phase of the ovarian cycle ("asymptomatic"). Prostaglandin synthase inhibitory activity in all samples was comparable to that previously found in adult women, and we found no difference in activity between the paired plasma samples, those obtained during symptomatic and asymptomatic times. Protein denaturation of the plasma by boiling also did not produce differences in prostaglandin synthase inhibition.

Adult↗
PubMed1983

Vaginal absorption of hexachlorophene during labor.

Surgical soap that contains hexachlorophene is used as an antiseptic lubricant for vaginal examinations during labor in some centers. Theoretically, hexachlorophene can be absorbed from the vaginal mucosa and be potentially toxic to the fetus and neonate. To evaluate vaginal absorption and placental transfer of hexachlorophene, we measured levels in mixed arterial/venous cord serum and postpartum maternal serum in 28 women whose vaginal examinations were lubricated with pHisoHex during labor. The serum of 12 women had detectable levels of hexachlorophene, with a high level of 942 ng/ml. Cord serum had detectable levels in nine neonates, with a high level of 617 ng/ml. The conclusion is that hexachlorophene from vaginal lubricants is variably absorbed from the vaginal mucosa, and appreciable amounts can be detected in maternal and cord serum. Because of the potential for neonatal hexachlorophene toxicity, we recommend the use of alternative lubricants for pelvic examinations during labor.

Absorption↗
PubMed1983

Stimulation of prostaglandin biosynthesis by urine of the human fetus may serve as a trigger for parturition.

Urine of the human fetus stimulated prostaglandin biosynthesis in vitro by increasing the conversion of arachidonic acid into prostaglandins. The stimulatory activity in urine from fetuses delivered at term after labor of spontaneous onset was greater than that in urine from fetuses delivered by cesarean section at term before the onset of labor. Such stimulation of prostaglandin biosynthesis by the fetal membranes, by way of a substance released into the urine and thence into amniotic fluid, could serve as a signal for the initiation of parturition.

Adult↗
PubMed1983

The effects of ritodrine on prostaglandin metabolite concentrations in the blood of pregnant baboons.

To investigate the relationship between beta sympathomimetic drugs and prostaglandins, we measured prostaglandin metabolites in the plasma of pregnant baboons that were given the drug ritodrine. Animals were at a mean gestation of 120 days, which is equivalent to 27 weeks in women. Ritodrine was infused i.v. at a rate of 23 micrograms/min or 80 micrograms/min for 4 h. Plasma concentrations of 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM), 11-deoxy-13,14-dihydro-15-keto-11,16-cyclo-prostaglandin E2 (PGEM-11), and 6-keto-prostaglandin-F1 alpha (6-keto-PGF1 alpha) were determined as indicators of the precursors, prostaglandin F2 alpha, prostaglandin E2, and prostacyclin (PGI2), respectively. At the 23 micrograms/min ritodrine infusion rate plasma levels of 6-keto-PGF1 alpha were decreased by 51% (+/- 15%) in the animals receiving the drug (p less than 0.005) whereas corresponding levels in control animals did not differ significantly from pre-infusion levels. At the 80 micrograms/min ritodrine infusion rate, the plasma levels of 6-keto-PGF1 alpha decreased by 66% (+/- 18%) compared with pre-infusion levels (p less than 0.001) but again the levels in control animals were not changed significantly. Plasma levels of PGFM and PGEM-11 in animals during ritodrine treatment did not differ significantly from baseline values.

Animals↗
PubMed1983

Biosynthesis of prostaglandins by tissues of the human fetus.

Human fetal tissues have been superfused and prostaglandin (PG)E2, PGF2 alpha and 6-keto-PGF1 alpha have been measured in the effluents using specific radioimmunoassays. In general, the rates of production of 6-keto-PGF by the tissues studied were greater than the rates of production of PGF2 alpha which in turn were greater than the rates of production of PGE2.

6-Ketoprostaglandin F1 alpha↗
PubMed1982

A sensitive radioimmunoassay for 11-deoxy-13, 14-dihydro-15-keto-11, 16-cyclo-prostaglandin E2: application as an index of prostaglandin E2 biosynthesis during human pregnancy and parturition.

A radioimmunoassay for 11-deoxy-13, 14-dihydro-15-keto-11, 16-cycloprostaglandin E2 (PGEM-II) is described. At pH 10.5, in the presence of albumin, 13, 14-dihydro-15-keto-prostaglandin E2 (PGEM-I) is transformed quantitatively into PGEM-II. Hence, after plasma samples are subjected to this transformation procedure, PGEM-II can be measured in such samples and be a true reflection of PGEM-I production and thereby prostaglandin E2 (PGE2) biosynthesis. The antiserum raised against PGEM-II is minimally cross-reactive with all prostaglandins tested (less than 0.01%). The mean least detectable mass of PGEM-II is 0.8 pg and the mean mass of added PGEM-II required to displace zero-point binding by 50% is 16.6 pg. The assay meets all the standard criteria for accuracy, reproducibility and parallelism. Concentrations of PGEM-II measured by this assay in peripheral plasma from men and nonpregnant women are similar to those reported for PGEM-I after measurements by gas chromatography - mass spectrometry. Plasma concentrations of PGEM-II in men were greater than in nonpregnant women. PGEM-II in increased concentration was found in early pregnancy although concentrations declined in the third trimester until labor when a significant increase was found. Concentrations of PGEM-II in umbilical venous plasma were significantly greater than those in maternal plasma.

Adult↗