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Optimized conditions for the chiral crystallization of ethylenediamine sulfate, which can serve as an ideal undergraduate experiment, are described. Large, flat, colorless crystals of ethylenediamine sulfate are obtained in an undisturbed evaporation dish within a period of approximately five to seven days. The crystals are ideal for polarimetry studies and observation using Polaroid sheets. Students become familiar with polarizing filters and how they can be used to distinguish between dextrorotatory and levorotatory crystals. Of 100 randomly sampled crystals, 47 crystals showed a (+)-rotation, while 53 crystals showed a (-)-rotation. The absolute value of the average optical rotation of the 100 crystals was found to be 158/mm ± 2 for the D line of sodium. The relative direction of rotation of polarized light was also determined by simply observing the change in optical rotatory dispersion of the crystals placed between two Polaroid sheets as one of the sheets was rotated clockwise or counter clockwise.

INTRODUCTION: Chronic histiocytic intervillositis (CHI) of the placenta is associated with serious adverse pregnancy outcomes not only in the index pregnancy but also in subsequent pregnancies. This study's aim was to propose an algorithm for the management of pregnancies following a histopathologic diagnosis of CHI. METHODS: We conducted a retrospective cohort study at a tertiary-level hospital that included CHI cases and controls matched by age, ethnicity, body mass index and pre-existing medical comorbidities, in a 1:2 ratio. We compared first- and second-trimester biomarkers for fetal aneuploidy, serum alkaline phosphatase (ALKP) and antenatal ultrasound findings, considering a p-value of <0.05 as statistically significant. RESULTS: We included 33 cases of CHI and 66 matched controls. The two groups were comparable except with regard to prior (92.6% vs. 43.3%, p<0.001) and current (87.9% vs. 42.2%, p<0.001) adverse obstetric outcomes. There were significant differences between groups in terms of abnormal first-trimester biomarkers in general (55.6% vs. 16.2%, p=0.003), and PAPP-A in particular (46.7% vs. 7.1%, p=0.005), second-trimester alpha-fetoprotein (25% vs. 0%, p=0.006), third-trimester ALKP levels (38.5% vs. 0%, p=0.045); second-trimester placental ultrasound findings (abnormal dimensions in 40% vs. 5.6%, p=0.02 and abnormal echotexture in 25% vs. 0%, p=0.047); third-trimester placental morphology (44% vs. 16.7%, p=0.009), umbilical artery Doppler studies (76% vs. 11.1%, p<0.001) and oligohydramnios (40% vs. 3.7%, p<0.001). CONCLUSION: The differences in biomarker and ultrasound findings between cases and controls was used to propose an algorithm for management of subsequent pregnancies, in terms of maternal and fetal surveillance, administration of antenatal corticosteroids and timing of delivery.