Transport kinetics of chromium in perfused human placental lobule in late gestation: in vitro study

Objective: Reports relating to maternal-fetal transport kinetics of chromium, an essential trace element in the human pregnancies are scanty. Hence, we thought it interesting to investigate the transport kinetics of this trace element in the human placenta in late gestation in vitro. Methods: Human placentae were collected immediately after delivery from normal uncomplicated pregnancies. Chromium chloride solution (GFS Chem Inc, Ohio, USA) at 10 times the physiological concentrations and antipyrine (Sigma Chem Co., St. Louis, USA) as internal reference marker was injected as a single bolus (100 µl) into the maternal arterial circulation of perfused placental lobules and perfusate samples were collected from maternal and fetal circulations over a study period of 5 minutes. National culture and Tissue collection medium, diluted with Earle's buffered salt solution was used as the perfusate. Serial perfusate samples were collected from fetal venous perfusate for a period of 30 minutes. Chromium concentration in perfusate samples was determined using atomic absorption spectrophotometry and the concentration of reference marker, antipyrine was measured by spectrophotometry. Transport kinetics and transport parameters of study and reference markers were assessed using well-established parameters. Results: Differential transport rates of chromium and antipyrine in 10 perfusions differed significantly for 10 and 50% efflux fractions (ANOVA test, p < .05) while those of 25, 75, and 90% efflux fractions were not significantly different between the study and reference substances. Chromium transport fraction (TF) averaged 54.9% of bolus dose in 10 perfusions while that of antipyrine averaged 89% of bolus dose, representing 61.80% of reference marker TF. The difference observed in TF values of chromium and antipyrine was statistically significant (Student's t-test, p < .05). Pharmacokinetic parameters such as area under the curve, clearance, absorption rate, elimination rate of chromium compared to reference marker was significantly different (ANOVA test, p < .05) between the study and reference substances. Conclusions: Our studies report for the first time maternal-fetal transport kinetics of chromium in human placenta in vitro. Considering the restricted transfer of this essential trace element from maternal to fetal circulation despite its small molecular weight, we hypothesize an active transport of chromium across the human placental membrane. Further studies relating to placental transport kinetics of this trace element in various pregnancy-related disease states are in progress.

Effect of methotrexate administration on status of some essential trace elements and antioxidant enzymes in pregnant rats in late gestation

OBJECTIVE

Folate antagonists are widely used in the treatment of various cancerous states. Paucity of data on effect of administration of one such widely used drug, methotrexate (MTX), on the status of essential trace elements and antioxidant enzymes in pregnant women or in pregnant animals prompted us to undertake this study.

METHODS

MTX at a concentration of 5 mg/kg body weight was administered intraperitoneally as single dose to pregnant Sprague-Dawley rats for three consequitive days from day 17 of pregnancy. Control group of pregnant rats received single dose of saline instead of the anti-cancer drug on all the 3 days. After receiving the third dose of drug, the treated rats and control group rats were sacrificed, 1 h after intraperitoneal injection of a cocktail of essential trace elements namely, Cu, Se and Zn administered as a single bolus dose. Blood samples were collected 30 min of trace element cocktail injection, after decapitation and concentrations of trace elements in serum samples were determined by atomic absorption spectrophotometry. Concentrations of antioxidant enzymes, such as superoxide dismutase, glutathione peroxidase and total antioxidant status were determined by specific analytical kits, using spectrophotometry.

RESULTS

In control group(n = 6), serum concentrations of Cu, Se and Zn averaged 2330.5, 614.8 and 2773.2 microg/l, while in study group (n = 6) the concentrations of trace elements averaged 2294, 596 and 2713 microg/l, respectively. Student's t-test did not show any statistical significance (p > 0.05) between various trace element concentrations in control and treated groups. Cu:Zn ratios of control and treated group of rats did not vary significantly as well. Concentrations of superoxide dismutase, glutathione peroxidase in whole blood samples in control rats averaged 165 and 43,260 U/ml, respectively, while in MTX-treated group of animals the corresponding antioxidant enzymes averaged 330.6 and 67,101 U/ml respectively. SOD and GPX values were significantly higher in drug-treated animals compared to controls (Student's t-test, p < 0.05) However, total antioxidant activity was shown to be significantly lower (Student's t-test; p < 0.05) in the drug-treated group compared to control.

CONCLUSIONS

We report for the first time that effect of MTX administration in pregnancy is not associated with significant alteration in disposition of essential trace elements. However, the effect of drug administration on antioxidant enzyme status in pregnant women cannot be excluded while using the drug in clinical states.

Magnesium sulphate therapy in women with pre-eclampsia and eclampsia in Kuwait

OBJECTIVE

To evaluate the outcome of the use of MgSO4 therapy in women with severe pre-eclampsia in Kuwait from January 2002 to December 2004.

SUBJECTS AND METHODS

The study involved 450 women managed at the Maternity Hospital in Kuwait with a blood pressure of 160/110 mm Hg and proteinuria of >0.3-5 g/24 h. A loading dose of 4 g MgSO4 was administered intravenously over 20 min and then the maintenance dose continued at 1 g/h for 24 h postpartum. Magnesium sulphate toxicity was monitored by urine output, deep tendon reflexes and serum magnesium levels and managed with an infusion of 10 ml of 10% calcium gluconate and cessation of magnesium infusion. Adjunct therapy included intravenous hydralazine 10 mg and labetalol 100 mg. The mode of delivery was determined after stabilizing the patient.

RESULTS

The women included Kuwaitis (n = 200, 44.4%), Asians (n = 129, 28.7%) and other Arabs (n = 116, 25.8%) with a mean age of 29.7 +/- 6.7 years (primigravida: n = 233, 51.8%; other parities: n = 217, 48.2%). Antenatal complications included intra-uterine growth restriction (n = 136, 30.2%), oliguria (n = 39, 8.7%), haemolysis, elevated liver enzymes and low platelet count syndrome (n = 30, 6.6%), abruptio placentae (n = 20, 4.4%), eclampsia (n = 15, 3.3%), and preterm birth (n = 253, 55.2%). Caesarean section (n = 241, 53.6%) was the main mode of delivery. The perinatal mortality rate was 27 per 1,000. Magnesium sulphate toxicity observed as reduced tendon reflexes occurred in 14 (3.1%) patients and flushing, nausea and vomiting and blocked nostrils in 86 (19.1%). There was no association between adverse outcomes and maternal serum magnesium concentrations and no maternal mortality occurred.

CONCLUSION

Magnesium sulphate was effective in preventing recurrence of eclamptic fits and safe for both mother and fetus.

Maternal-foetal status of copper, iron, molybdenum, selenium and zinc in obese gestational diabetic pregnancies

Obesity is well known to be a contributory risk factor for several disease states, including diabetes mellitus. Paucity of data on maternal-foetal status of essential trace elements in obese diabetic pregnancies prompted us to undertake this study. Maternal venous and umbilical arterial and venous blood samples were collected from obese gestational diabetic patients (Body Mass Index (BMI) >30) and control obese pregnant women (BMI>30) at time of spontaneous delivery or caesarean sections and concentrations of essential trace elements such as Cu, Fe, Mo, Se and Zn were determined in various samples by atomic absorption spectrophotometry. Activities of antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPX) and total antioxidant (TAO) in maternal and umbilical blood were assessed using appropriate reagent kits. Maternal-foetal disposition and exchange parameters of elements studied were assessed using established criteria. Concentrations of Cu, Fe, Mo, Se and Zn in serum of control obese pregnant women (n=10) averaged 2404, 2663, 11.0, 89.0 and 666 microg/l respectively, while in the obese diabetic group (n=11), the corresponding values averaged 2441, 2580, 13.3, 85.1 and 610 microg/l respectively. Activities of antioxidant enzymes such as SOD, GPX and TAO were not significantly different in maternal veins of control and diabetic groups. Varying differences were noted in the case of antioxidant enzyme activities in umbilical blood samples of control and study groups. We conclude that obesity is not associated with significant alterations in antioxidant enzyme status in gestational diabetes and only with relatively minor alterations in status of some essential trace elements.

Placental pathology in relation to the White's classification of diabetes mellitus

The objective of this study was to investigate various macroscopic and microscopic features of the placenta in pregnancies complicated by diabetes according to White's classification. A total of 148 placentas were studied. Sixty-five were from control patients and 83 from diabetic mothers. The diabetic mothers were further divided into three groups according to White's classification. There were 40 cases in White's group A and 36 cases in White's group B. There were 7 cases in White's groups C and D combined. Advanced maternal age and grandmultiparity were significantly higher in White A, White B and White C&D compared to the normal group. Mean weight of the mother was higher in White group A and group B compared to the control group and group C&D. The placental weight and neonatal weight were increased provided the diabetes was not complicated by vascular disease. With accompanying vascular disease the placental weight and neonatal weight were reduced compared to the controls. As a result of increased perinatal jeopardy the rate of operative delivery was higher in diabetic mothers. No major difference was observed in microscopic changes of placentas in different groups according to White's classification and the normal group.