Sherry L. Perkins

Thrombophilia and the Risk for Hemodialysis Vascular Access Thrombosis

Vascular access thrombosis is the most common and costly complication in hemodialysis patients. The role of thrombophilia in access thrombosis is not established. A case-control study was conducted of 419 hemodialysis patients to determine whether thrombophilia was associated with arteriovenous fistula or graft thrombosis. Participants were enrolled from three in-center and five satellite dialysis units associated with a Canadian academic health science center that provides dialysis services in a catchment area of one million. Patients were tested for factor V Leiden, prothrombin gene mutation, factor XIII genotype, methylenetetrahydrofolate reductase genotype, lupus anticoagulant, anticardiolipin antibody, factor VIII, homocysteine, and lipoprotein (a) concentrations. Overall, 59 (55%) patients with access thrombosis had at least one thrombophilia compared with 122 (39%) patients without access thrombosis (unadjusted odds ratio [OR], 1.91; 95% confidence interval [CI], 1.23 to 2.98). After controlling for important risk factors, the association between any thrombophilia and access thrombosis remained (adjusted OR, 2.42; 95% CI, 1.47 to 3.99). For each additional thrombophilic disorder, the odds of access thrombosis increased significantly (adjusted OR, 1.87; 95% CI, 1.34 to 2.61). This study suggests that thrombophilia is associated with access thrombosis in dialysis patients. Large, multicenter, prospective cohort studies are needed to confirm the observations from this case-control study.

The effect of tobacco exposure on the fetal hypothalamic–pituitary–adrenal axis

Objective  Our objective was to determine if maternal smoking is associated with programming of the fetal hypothalamic–pituitary‐adrenal (HPA) axis. Cigarette smoking, which induces a state of hypoxia in the fetus, may promote in utero‘programming’ of the HPA axis. In utero, adaptations to the HPA axis, which become maladaptive later in life, have been hypothesised to contribute to the development of adult cardiovascular disease and metabolic disorders.

Maternal smoking and fetal erythropoietin levels

Objective To determine the influence of maternal smoking on fetal erythropoietin concentrations in health term pregnancies and test the correlation between cotinine, a biomarker of maternal smoking, and erythropoietin levels in fetuses. Methods We invited women with healthy term pregnancies to participate in the study, excluding those with conditions previously known to be associated with elevated fetal erythropoietin levels. We recorded demographic data, smoking status, and labor outcome prospectively for each patient. Umbilical venous samples were collected, and serum was stored at −70C to be analyzed later for erythropoietin and cotinine. Umbilical arterial samples were tested for pH and base excess determination. We compared fetal erythropoietin and cotinine between smokers and nonsmokers and examined correlations between erythropoietin and cotinine. Kruskal-Wallis test, t test, median test, and Spearman rank correlation test were used when appropriate. Statistical significance was P < .05. Results We recruited 35 nonsmokers and 26 smokers and analyzed their samples. The two groups were comparable in demographics and birth outcomes, except for birth weights, which were lower in smokers. Fetal erythropoietin concentrations increased significantly with increasing maternal cigarette consumption, ranging from none to more than 15 cigarettes per day (P = .03). There was positive correlation between fetal erythropoietin and cotinine concentrations (r = .41; P = .04), suggesting a dose-response relationship. Conclusion Fetuses of smokers had increased erythropoietin concentrations that correlate positively with fetal cotinine levels; which suggests an increased risk of subacute hypoxia related to degree of maternal cigarette consumption.

The effect of tobacco exposure on maternal and fetal thyroid function.

OBJECTIVE To determine the effect of smoking on maternal and fetal thyroid function. STUDY DESIGN This prospective cohort study involved healthy women undergoing elective cesarean section for term singleton infants. Maternal and fetal thyroid indices were compared between smokers (n=21) and non-smokers (n=83). RESULTS Maternal thyrotropin (TSH) concentrations were significantly lower in smokers than non-smokers (1.75 mIU/L versus 2.15 mIU/L, respectively, p=0.007), with similar free thyroxine (FT4) concentrations (9.59 pmol/L versus 9.56 pmol/L, p=0.755). For women who smoked, the correlation between the average number of cigarettes smoked per day and maternal TSH concentrations was -0.427, p=0.054. Infants of smokers and non-smokers had similar umbilical TSH (5.43 mIU/L versus 5.82 mIU/L, p=0.124) and FT4 concentrations (13.06 pmol/L versus 13.57 pmol/L, p=0.049). CONCLUSION We demonstrated for the first time that women who smoke during pregnancy have significantly lower TSH concentrations than non-smokers.

Comparison of serum progesterone as an indicator of pregnancy nonviability in spontaneously pregnant emergency room and infertility clinic patient populations.

OBJECTIVE To compare the predictive value of serum progesterone in identifying nonviable pregnancy in symptomatic spontaneously pregnant emergency department patients and asymptomatic patients attending an infertility clinic. DESIGN Retrospective study. SETTING Tertiary-care academic health center. PATIENT(S) One hundred thirty-seven pregnant patients who presented to the emergency department for whom clinical outcomes were available, and 123 consecutive patients who became pregnant during treatment at the infertility clinic. INTERVENTION(S) Serum progesterone measurement. MAIN OUTCOME MEASURE(S) The sensitivity, specificity, and predictive value of serum progesterone <45 nmol/L in identifying nonviable pregnancies were determined for each of the groups. RESULT(S) Sensitivity and specificity of serum progesterone <45 nmol/L in predicting nonviable pregnancies were 88.6% and 87.5%, respectively, in spontaneously pregnant patients who presented to the emergency department with pain or bleeding and 58.8% and 100% in infertility patients who had undergone controlled ovarian hyperstimulation for in vitro fertilization or intrauterine insemination. Sensitivity and specificity for all other infertility clinic patients were variable. CONCLUSION(S) The predictive value of low serum progesterone in identifying nonviable pregnancies varies with patient populations.

A rapid high-performance thin-layer chromatographic urine screen for laxative abuse.

Laxative abuse, if unrecognized, can lead to unnecessary and costly investigations. The stimulants and cathartics are the most commonly abused laxatives and have the potential for causing the most long-term damage. We have optimized a solid-phase extraction coupled with high-performance thin-layer chromatography (HPTLC) to provide rapid, simple, and sensitive detection of phenolphthalein, danthron, rhein, aloin, and bisacodyl and its metabolites in urine. Positive screens have revealed laxative abuse in 3 of 42 samples from patients presenting with diarrhea of unknown origin.

Folic Acid Supplementation in Pregnancy and the Risk of Pre-Eclampsia—A Cohort Study

This prospective cohort study designed to assess the effect of folic acid supplementation in pregnancy on the risk of preeclampsia (PE) took place in Ottawa, ON and Kingston, ON, Canada, from September 1, 2002 to August 31, 2008. Pregnant women, less than 20 weeks gestational age were recruited and delivered in the Ottawa region and the Kingston General Hospital. Demographic characteristics of the study participants and the patterns of supplementation of folic acid were described and occurrence of PE between women with folic acid supplementation during pregnancy and women without were compared. Multiple logistic regression was used in the estimation of the independent effect of supplementation of folic acid. Additional analyses assessing the effect of low RBC and serum folate and dose-response relationship were performed. Analyses were performed in all study participants, and then in high risk and low risk sub-groups, respectively. A total of 7,669 participants were included in the final analysis. Ninety five percent of the study participants were taking folic acid supplementation in early second trimester. The rate of PE was lower in the supplementation group than in the no supplementation group, and the difference was statistically significant in high risk women. Similar patterns of associations were observed in analysis by RBC and serum folate levels and in dose-response analysis. Folic acid supplementation in pregnancy may reduce PE risk in pregnant women, especially in those women with increased risk of developing PE.

LABORATORY AND CLINICAL EVALUATION OF TWO GLUCOSE METERS FOR THE NEONATAL INTENSIVE CARE UNIT

OBJECTIVE To evaluate the analytical and clinical performance of the One Touch II and Advantage glucose meters for use in neonatal specimens. DESIGN AND METHODS For the laboratory evaluation, a total of 96 umbilical cord whole blood specimens were analyzed on the One Touch II and/or Advantage meters. Samples were centrifuged after analysis on the meters and plasma glucose was determined on the Hitachi 917. For the clinical evaluation, a total of 64 infants had specimens analyzed on each of the meters as well as on the laboratory analyzer. RESULTS In the laboratory and clinical evaluations, both meters correlated well (r > 0.9, p < 0.001) with the plasma values for the Hitachi 917. However, the mean difference between the Advantage and Hitachi 917 was lower than that of the One Touch II in both the laboratory (-0.23 vs -0.64 mmol/L) and the clinical evaluations (-0.08 vs -0.60 mmol/L). 53.1% of One Touch and 26.6% of Advantage results from the clinical study had a discrepancy of > 0.5 mmol/L from the laboratory value. CONCLUSIONS For neonatal specimens, glucose meters must have good low end precision, sensitivity and accuracy, In this study, the Advantage meter had fewer discordant results and better correlation with the Hitachi 917. Overall, nursing and laboratory staff preferred the performance and characteristics of the Advantage meter.

Effect of Smoking on Fibronectin Production by Human Amnion and Placenta

Fibronectin production from amnion and placental tissues was evaluated in pregnant woman smokers and nonsmokers in order to examine if there were alterations of fibronectin metabolism in intrauterine tissues. In both amnion and placental tissues, cycloheximide inhibited the fibronectin output indicating that it was being synthesized. Mean fibronectin output by amnion in pregnant woman smokers was significantly lower than that in pregnant woman nonsmokers. In contrast, in the placenta from pregnant woman smokers, the output was significantly higher than that in pregnant woman nonsmokers. The present observations indicate that smoking alters an important biochemical constituent in amnion and placenta, possible leading to some complications.

Serum progesterone in predicting pregnancy outcome after assisted reproductive technology.

Purpose:Our purpose was to determine whether serum progesterone predicts pregnancy outcome after superovulation.Methods:One hundred twenty-three consecutively pregnant patients were divided into three groups: group I, 55 patients following superovulation for assisted reproductive technologies; group II, 23 patients after correction of oligoovulation; and group III, 45 patients who conceived spontaneously. When β-human chorionic gonadotropin was positive, progesterone was measured on the same serum sample. A serum progesterone level of 45 μm/L was set to differentiate between nonviable pregnancy and ongoing pregnancy.Results:In group I, zero (0%) of 38 ongoing pregnancies and 10 (59%) of 17 nonviable pregnancies were observed with a progesterone level of <45 μm/L [14.2 ng/ml (P < 0.001)]. In group II, 4 (27%) of 15 ongoing pregnancies and 5 (63%) of 8 nonviable pregnancies had a progesterone level of <45 μm/L (P = NS). In group III, 10 (42%) of 24 ongoing pregnancies and 15 (71%) of 21 nonviable pregnancies were observed with a progesterone level of <45 μm/L (14.2 ng/ml) (P = NS).Conclusions:A serum progesterone level of <45 nM predicts nonviable pregnancy after superovulation for assisted reproductive technology.