RESUMEN
Coordination cages obtained upon complexation of pyridyl functionalized porphyrins by Ag+ disassemble when overtaking a 1 : 2 stoichiometric amount of silver salt. An excess of Ag+ then leads to unusual chemical processes, here analyzed in detail, which permanently transform the monomeric porphyrins. The observed processes, discussed with reference to model compounds devoid of polyether substituted pyridyl residues, evidence a peculiar reactivity for meso 2,6-dimethylphenyl substituted porphyrins.
RESUMEN
To compare multiple and singleton pregnancies in the treatment of threatened preterm delivery with prolonged intravenous ritodrine, 32 women with multiple pregnancy (26 twins, 6 triplets, 70 fetuses, 30.3 +/- 3.5 weeks) and 51 women with singleton pregnancy (31.3 +/- 2.6 weeks) admitted for threatened preterm delivery without rupture of the membranes were the subjects of a retrospective study of obstetric data, perinatal outcome and maternal adverse effects. Significance was assessed by chi 2 test and Student's t test. Multiple pregnancies were associated with a marked increase in the duration of tocolysis (17.2 +/- 17.3 vs. 7.6 +/- 8.1 days, P < 0.01), incidence of delivery before 37 weeks (87.5 vs. 35.3%, P < 0.01) and incidence of maternal cardiovascular complications (34.4 vs. 4.0%, P < 0.01), including three cases of pulmonary edema. The incidences of delivery before 32 weeks (12.5 vs. 7.8%) and of neonatal death (2.9 vs. 0%) were not significantly different in the two groups. Multiple pregnancies dramatically increased the incidence of maternal adverse effects of prolonged intravenous ritodrine therapy. Neonatal benefit is questionable and was difficult to establish since it was not a randomized study.
