Placenta previa of a succenturiate lobe: a report of two cases

Previa of a succenturiate placenta is a rare condition. We report two cases of such lesions, which could not be detected by transabdominal ultrasound. When no cause of uterine bleeding is detected, previa of a posterior succenturiate lobe should be considered, and transvaginal ultrasound should be performed.

Uroguanylin level in umbilical cord blood

BACKGROUND

Uroguanylin is a novel natriuretic and diuretic peptide originally isolated from urine.

METHODS

To determine whether uroguanylin has a physiologic role during the perinatal period, uroguanylin levels in umbilical cord plasma obtained at the time of delivery were measured by radioimmunoassay and compared with cord serum osmolality.

RESULTS

Mean (+/- SD) cord plasma uroguanylin concentrations (8.8 +/- 2.1 fmol/mL) were higher compared with normal adult values. The extent of maturity, mode of delivery and gender did not appear to influence cord uroguanylin levels. The uroguanylin concentration had a significant positive correlation with cord serum osmolality.

CONCLUSION

These findings support some regulatory role of this peptide in perinatal renal and cardiovascular adaptation.

Unicornuate uterus with a noncommunicating cavitary, laterally dislocated rudimentary horn presenting with adenomyosis, associated with ipsilateral renal agenesis

Unicornuate uterus with a rudimentary horn is a rare müllerian anomaly. We report a case of a unicornuate uterus with adenomyosis in a laterally dislocated rudimentary horn, which showed a functioning endometrial islands, with associated ipsilateral agenesis of the kidney.

Site-directed mutagenesis of surfactant protein A reveals dissociation of lipid aggregation and lipid uptake by alveolar type II cells

Surfactant protein A (SP-A) binds to dipalmitoylphosphatidylcholine (DPPC) and induces phospholipid vesicle aggregation. It also regulates the uptake and secretion of surfactant lipids by alveolar type II cells. We introduced the single mutations Glu195-->Gln (rE195Q), Lys201-->Ala (rK201A) and Lys203-->Ala (rK203A) for rat SP-A, Arg199-->Ala (hR199A) and Lys201-->Ala (hK201A) for human SP-A, and the triple mutations Arg197, Lys201 and Lys203-->Ala (rR197A/K201A/K203A) for rat SP-A, into cDNAs for SP-A, and expressed the recombinant proteins using baculovirus vectors. All recombinant proteins avidly bound to DPPC liposomes. rE195Q, rK201A, rK203A, hR199A and hK201A function with activity comparable to wild type SP-A. Although rR197A/K201A/K203A was a potent inducer of phospholipid vesicle aggregation, it failed to stimulate lipid uptake. rR197A/K201A/K203A was a weak inhibitor for lipid secretion and did not competed with rat [125I]SP-A for receptor occupancy. From these results, we conclude that Lys201 and Lys203 of rat SP-A, and Arg199 and Lys201 of human SP-A are not individually critical for the interaction with lipids and type II cells, and that Glu195 of rat SP-A can be replaced with Gln without loss of SP-A functions. This study also demonstrates that the SP-A-mediated lipid uptake is not directly correlated with phospholipid vesicle aggregation, and that specific interactions of SP-A with type II cells are involved in the lipid uptake process.

Mutational analysis of Arg197 of rat surfactant protein A. His197 creates specific lipid uptake defects

In previous studies, tandem mutagenesis of Glu195 and Arg197 of surfactant protein A (SP-A) has implicated both residues as critical participants in the interaction of the molecule with alveolar type II cells and phospholipids. We substituted Ala, Lys, His, Asp, and Asn mutations for Arg to evaluate the role of a basic amino acid at position 197 in SP-A action. Unexpectedly, Ala197 retained complete activity in the SP-A functions of carbohydrate binding, type II cell binding, inhibition of surfactant secretion, lipid binding, lipid aggregation, and lipid uptake by type II cells. The results unambiguously demonstrate that Arg197 is not mechanistically essential for SP-A function. The Lys197 mutation displayed all functions of the wild type protein but exhibited a 2-fold increase in lipid uptake activity. The His197 mutation displayed all SP-A functions studied except for lipid uptake. The results obtained with the His197 mutation clearly demonstrate that lipid aggregation alone by SP-A is insufficient to promote lipid uptake by type II cells. These findings indicate that specific interactions between type II cells and SP-A are involved in the phospholipid uptake processes.

The mannose-binding protein A region of glutamic acid185-alanine221 can functionally replace the surfactant protein A region of glutamic acid195-phenylalanine228 without loss of interaction with lipids and alveolar type II cells

Pulmonary surfactant protein A (SP-A) is a C-type lectin that regulates the uptake and secretion of surfactant lipids by alveolar type II cells and binds dipalmitoylphosphatidylcholine (DPPC) and galactosylceramide (GalCer). We isolated mannose-binding protein A (MBP-A) from rat sera, which is structurally analogous to SP-A, and examined if it was functionally equivalent to SP-A. We found that MBP-A did not possess the ability to interact with lipids and type II cells. The purpose of this study was to investigate the SP-A region involved in binding lipids and interacting with type II cells by using chimeric proteins with MBP-A. Chimeras AM1, AM2, and AM3 were constructed with SP-A/MBP splice junctions at Cys218/Gln210, Lys203/Cys195, and Gly194/Glu185, respectively. All of the chimeras bound DPPC and GalCer with activity comparable to recombinant SP-A. The three chimeras retained the ability to induce phospholipid vesicle aggregation and augment lipid uptake by type II cells, albeit to a lesser extent than wild type SP-A. The chimeras inhibited lipid secretion from type II cells with an IC50 of 0.5 microg/mL and competed effectively for SP-A receptor binding. In addition all these chimeras contained the epitope for monoclonal antibody 1D6, which blocks specific SP-A function. From these results, we conclude that the MBP-A region of Glu185-Ala221 can functionally replace the homologous SP-A region of Glu195-Phe228 without loss of interaction with lipids and type II cells.

Interaction of phospholipid liposomes with plasma membrane isolated from alveolar type II cells: effect of pulmonary surfactant protein A

Pulmonary surfactant protein A (SP-A) augments the uptake of phospholipid liposomes containing dipalmitoylphosphatidylcholine (DPPC) by alveolar type II cells. The SP-A-mediated uptake process of lipids by type II cells have not been well understood. In the present study we investigated the SP-A-mediated interaction of phospholipids with plasma membrane isolated from alveolar type II cells. SP-A increased the amount of liposomes containing radiolabeled DPPC associated with type II cell plasma membrane by 4-fold compared to the control without SP-A when analyzed by sucrose density gradient centrifugation. This effect is dependent upon the SP-A concentration. The enhancement was inhibited by anti-SP-A antibody and EGTA. When type II cell plasma membrane and liposomes containing [14C]DPPC and [3H]triolein were coincubated with or without SP-A, analysis on sucrose density gradients revealed that the profiles of [14C]DPPC and [3H]triolein in each fraction were almost identical with or without SP-A, indicating that SP-A mediates the binding of liposomes to plasma membrane but not transfer of DPPC. SP-A increased the association of liposomes containing DPPC with the membrane by 2-fold more than that containing 1-palmitoyl-2-linoleoyl-phosphatidylcholine (PLPC). SP-A induced aggregation of phospholipid liposomes containing PLPC as well as those containing DPPC, but the final turbidity of DPPC liposomes aggregated by SP-A was only by 15% greater than that of PLPC liposomes. The amount of DPPC liposomes associated with the plasma membrane derived from type II cells was 2-fold greater than that from liver. We speculate that the SP-A-mediated interaction of lipids with type II cell plasma membrane may contribute, in part, to the lipid uptake process by type II cells.