[Uterine rupture of the unscarred uterus: A report of 10 cases]. / Rupture utérine sur utérus non cicatriciel : à propos de 10 cas.

INTRODUCTION: Uterine rupture in the healthy uterus is a rare obstetrical complication, not much suspected and with badly identified risk factors. Thus, there exists frequent delay for treatment and therefore fetal-maternal important morbidity and mortality. This article describes clinical signs and symptoms, management, and maternal and neonatal prognosis of uterine rupture. METHODS: Descriptive retrospective study within 13 maternity hospitals, reporting 10 series of cases of uterine rupture on gravid healthy uterus during the third trimester of pregnancy. RESULT: The incidence was 2.8/100,000 births. Surgical treatment was conservative in 9 out of 10 cases, the maternal prognosis was good with no maternal deaths and 6 out of 7 patients had at least one subsequent pregnancy. The fetal prognosis was more reserved, with 2 fetal or neonatal deaths and 1 with motor disability. 6/6 patients (100%) had at least one iterative Caesarean section during the following pregnancies with healthy fetuses. CONCLUSION: In this series of 10 cases over 25years, maternal-fetal morbidity and mortality were significant, in agreement with the literature. Maternal prognosis remained favorable. When surgical treatment is conservative a subsequent pregnancy is possible and an iterative cesarean section must be performed.

Alzheimer's disease-like phosphorylation of the microtubule-associated protein tau by glycogen synthase kinase-3 in transfected mammalian cells.

BACKGROUND: Paired helical filaments (PHFs) are a characteristic pathological feature of Alzheimer's disease; their principal component is the microtubule-associated protein tau. The tau in PHFs (PHF-tau) is hyperphosphorylated, but the cellular mechanisms responsible for this hyperphosphorylation have yet to be elucidated. A number of kinases, including mitogen-activated protein (MAP) kinase, glycogen synthase kinase (GSK)-3 alpha, GSK-3 beta and cyclin-dependent kinase-5, phosphorylate recombinant tau in vitro so that it resembles PHF-tau as judged by its reactivity with a panel of antibodies capable of discriminating between normal tau and PHF-tau, and by a reduced electrophoretic mobility that is characteristic of PHF-tau. To determine whether MAP kinase, GSK-3 alpha and GSK-3 beta can also induce Alzheimer's disease-like phosphorylation of tau in mammalian cells, we studied the phosphorylation status of tau in primary neuronal cultures and transfected COS cells following changes in the activities of MAP kinase and GSK-3. RESULTS: Activating MAP kinase in cultures of primary neurons or transfected COS cells expressing tau isoforms did not increase the level of phosphorylation for any PHF-tau epitope investigated. But elevating GSK-3 activity in the COS cells by co-transfection with GSK-3 alpha or GSK-3 beta decreased the electrophoretic mobility of tau so that it resembled that of PHF-tau, and induced reactivity with eight PHF-tau-selective monoclonal antibodies. CONCLUSIONS: Our data indicate that GSK-3 alpha and/or GSK-3 beta, but not MAP kinase, are good candidates for generating PHF-type phosphorylation of tau in Alzheimer's disease. The involvement of other kinases in the generation of PHFs cannot, however, be eliminated. Our results suggest that aberrant regulation of GSK-3 may be a pathogenic mechanism in Alzheimer's disease.

PHF-tau from Alzheimer's brain comprises four species on SDS-PAGE which can be mimicked by in vitro phosphorylation of human brain tau by glycogen synthase kinase-3 beta.

Extensive in vitro phosphorylation of a purified preparation of control human brain tau consistently produces four rather than, as previously believed, three tau species on SDS-PAGE. The species thus generated are shifted on SDS-PAGE to positions that match those of PHF-tau isolated from Alzheimer's disease brain. A mixture of recombinant human tau isoforms phosphorylated by GSK-3 beta gave similar results to those obtained with control human brain tau. In vitro phosphorylation of the individual recombinant isoforms by GSK-3 beta showed that the four bands of PHF-tau are likely to consist of isoforms 3R,0 alone; 4R,0 with 3R,29; 4R,29 with 3R,58 and 4R,58 alone.

The antigenic sites of trichosanthin, a ribosome-inactivating protein with multiple pharmacological properties.

Trichosanthin (TCS) fragments were produced by Tn1000 deletion mutagenesis and by cyanogen bromide (CNBr) cleavage and their immunoreactivity was examined by incubating with various antibodies. Twelve C-terminally truncated TCS variants were successfully synthesized under the control of a T7 RNA driven promoter. The smallest antigenic fragment mapped corresponded to the N-terminal 20 amino acids (aa). Six CNBr fragments of TCS were created and identified by electrospray mass spectrometry and N-terminal sequencing. Three antigenic fragments corresponding to aa 1-72, 101-152 and 153-246, respectively were mapped. Fragments corresponding to aa 1-72 and 153-246 were immunoreactive to the same monoclonal antibody showing they are components of a discontinuous epitope. On the other hand, the fragment containing aa 73-100 was not detected by any of the antibodies used.

Engineering of a mini-trichosanthin that has lower antigenicity by deleting its C-terminal amino acid residues.

Trichosanthin is a ribosome-inactivating protein that possesses antitumor and antiviral activities. Clinical trials of trichosanthin on AIDS patients, however, elicit anaphylactic reactions. To reduce the antigenicity of trichosanthin as a drug while preserving its biological activity, the C-terminal domain (residues 203 to 247), which contains a putative antigenic site, was systemically deleted. We have found that the minimum length of trichosanthin that can fold into an active conformation is residue 1 to 240. The mini-trichosanthin (C7) generated by deleting the last seven C-terminal amino acid residues has 2.7-fold decrease in antigenicity, 10-fold reduction in in vitro ribosome-inactivation activity, and in vivo cytotoxicity toward K562 cells, and 2-fold reduction in abortificient activity. Structural analyses of C7 indicate decrease in the helix content, increased exposure of Trp192, and lower thermodynamic stability. The deletion of the C-terminal residues (Leu241 to Ala247) probably perturbs local structure of the C-terminal antigenic epitope that results in the decrease in antigenicity and activities of C7.

Structure/function relationship study of Tyr14 and Arg22 in trichosanthin, a ribosome-inactivating protein.

Amino acids Tyr14 and Arg22 in trichosanthin are residues on helix A1 close to the active-site cleft. They are invariant in various type-I and type-II ribosome-inactivating proteins. In this study, Tyr14 was changed to Phe and Arg22 to Lys and Leu. Modified proteins were purified, and activities compared by assaying their median inhibitory concentration (ID50) on a rabbit-reticulocyte-lysate protein-synthesis system. While the ID50 of wild-type trichosanthin was 0.02 nM, those for [Phe14], [Lys22], [Leu22] and [Phe14, Leu22]trichosanthin were 0.10, 0.03, 0.25 and 0.15 nM, respectively. Therefore, compared with Tyr14, Arg22 appears to play a more important role in trichosanthin. Structural studies on [Leu22]trichosanthin showed that two water molecules occupy the space left by the side chain of Arg22, and hydrogen bonds exist between these water molecules and nearby residues to retain the conformation. The use of intermolecular rather than intramolecular hydrogen bonds may have an adverse effect on stability or folding of the protein and results in a mild decrease in activity.