Cystic fibrosis in pregnancy.

OBJECTIVE: To review the outcomes of pregnancies in women with cystic fibrosis (CF) and to address issues pertinent to the obstetric care of such women. DATA SOURCES: English-language case reports and case series published from 1960 to 1991 identified through a search of MEDLINE and Index Medicus. The terms of reference were "cystic fibrosis" and "pregnancy". Not all the reports reviewed addressed all the outcomes under consideration. STUDY SELECTION: A total of 20 reports citing cases of pregnancy in women with CF. DATA EXTRACTION: Outcomes included the number of spontaneous abortions, pregnancies continued beyond 20 weeks, preterm deliveries, maternal deaths at 6 months and 2 years after delivery and perinatal deaths. Breast-feeding was addressed. Measures to assess the severity of maternal disease included the mean age at diagnosis of CF, weight gain during pregnancy, pulmonary function studies if available and the need for pancreatic enzyme replacement therapy. DATA SYNTHESIS: Of 217 pregnancies in 162 women spontaneous abortion occurred in 10 (4.6%). Pregnancy progressed beyond 20 weeks in 81.6% of cases; 24.3% of the deliveries were preterm. The maternal death rate did not exceed that among age-related women with CF who were not pregnant. The rate of perinatal death was 7.9%. Breast milk was not hypernatremic. Poor outcomes were associated with a weight gain of less than 4.5 kg and a forced vital capacity of less than 50% of the predicted value. CONCLUSIONS: Premature labour and delivery remain a significant risk for pregnant women with CF, contributing to a high rate of perinatal death. Maternal illness and death result from deteriorating pulmonary function. Breast-feeding is not contraindicated. Attention to energy intake and pulmonary function is important.

Bacteriophage Mu sites required for transposition immunity.

Plasmids with bacteriophage Mu sequences receive additional Mu insertions 20-700 times less frequently than plasmids without Mu sequences. The Mu sites required for this transposition immunity were mapped near each end, either of which was sufficient. The left site was between 127 and 203 base pairs from the left end, and the right site was between 22 and 93 base pairs from the right end. These sequences include the innermost but not the outermost of the three binding sites for the Mu A transposition protein at each end of Mu. Transposition immunity was cis-acting and independent of its location on a target plasmid. An additional copy of an immunity site reduced transposition a factor of 10 further. Transposition immunity was seen both during full phage lytic growth, with all the bacteriophage Mu genes, and during normal cellular growth, with a mini-Mu element containing only the Mu c and ner regulatory and A and B transposition genes.

Heat modifiability and detergent solubility of outer membrane proteins of Rhodopseudomonas sphaeroides.

The outer membrane fraction from Rhodopseudomonas sphaeroides was isolated by isopycnic density centrifugation. The purity of this fraction was assayed by several methods. When the outer membrane fraction obtained after French press lysis of cells was compared with the outer membrane fragments released during spheroplast formation, the polypeptide profiles were identical. Detergent solubilization of membrane fractions showed that Triton X-100 nonselectively solubilizes both the cytoplasmic membrane and the outer membrane, whereas Deriphat 160 selectively solubilizes the cytoplasmic membrane. Several outer membrane polypeptides, including the major outer membrane protein, exhibited changes in electrophoretic mobility that depended upon the temperature of solubilization in sodium dodecyl sulfate. Solubilization at room temperature in the presence of ions reproduced the effect of thermal denaturation on the major outer membrane polypeptide.