Suspected skeletal dysplasias: femur length to abdominal circumference ratio can be used in ultrasonographic prediction of fetal outcome

OBJECTIVES: Skeletal dysplasias are a group of bone growth disorders, some of which can be recognized prenatally. Certain types of skeletal dysplasias result in a lethal fetal outcome. The ability to predict this outcome prenatally would be important in counseling parents. This study evaluated the ratio of femur length to abdominal circumference as a predictor of fetal outcome in cases of suspected skeletal dysplasia. STUDY DESIGN: This 3-year retrospective study identified 18 cases of prenatally suspected skeletal dysplasia from a population of approximately 35,000 fetuses undergoing prenatal ultrasonography. The femur length/abdominal circumference ratio was calculated and compared with fetal-neonatal outcomes and diagnoses. RESULTS: Eighteen cases of suspected skeletal dysplasia were identified, and the femur length/abdominal circumference ratio was found to be a good predictor of fetal outcome independent of gestational age. A ratio < 0.16 resulted in a lethal outcome in nine of nine cases. Conversely, a ratio > or = 0.16 resulted in a diagnosis of a nonlethal form of skeletal dysplasia or a diagnosis that ruled out any form of skeletal dysplasia in nine of nine cases. CONCLUSIONS: The femur length/abdominal circumference ratio may be useful to predict a lethal fetal outcome when ultrasonography indicates a possible skeletal dysplasia.     

Structural polymorphism of the RecA protein from the thermophilic bacterium Thermus aquaticus

The Escherichia coli RecA protein has served as a model for understanding protein-catalyzed homologous recombination, both in vitro and in vivo. Although RecA proteins have now been sequenced from over 60 different bacteria, almost all of our structural knowledge about RecA has come from studies of the E. coli protein. We have used electron microscopy and image analysis to examine three different structures formed by the RecA protein from the thermophilic bacterium Thermus aquaticus. This protein has previously been shown to catalyze an in vitro strand exchange reaction at an optimal temperature of about 60 degrees C. We show that the active filament formed by the T. aquaticus RecA on DNA in the presence of a nucleotide cofactor is extremely similar to the filament formed by the E. coli protein, including the extension of DNA to a 5.1-A rise per base pair within this filament. This parameter appears highly conserved through evolution, as it has been observed for the eukaryotic RecA analogs as well. We have also characterized bundles of filaments formed by the T. aquaticus RecA in the absence of both DNA and nucleotide cofactor, as well as hexameric rings of the protein formed under all conditions examined. The bundles display a very large plasticity of mass within the RecA filament, as well as showing a polymorphism in filament-filament contacts that may be important to understanding mutations that affect surface residues on the RecA filament.     

Expression of an inter-alpha-trypsin inhibitor heavy chain-like protein in the pig endometrium during the oestrous cycle and early pregnancy

Triploidies are pregnancies that show a 69 chromosome karyotype. This chromosomal abnormality gives rise to early abortion in most cases. Triploid pregnancies, after the first three months, become molar pregnancies (molar changes inside the placenta with identifiable embryonic structures and a preeclampsia) or non molar pregnancies (isolated intauterin growth retardation). Several possibilities concerning the origin of the additional set of chromosomes exist: dispermy (the most common), diandry and digyny. The maternal and fetal clinical manifestations of this chromosomal abnormality are very diverse, which explains the difficulty of finding and recognizing this pathology. Mac Fadden's classification does not explain all the phenotypic triploid physiopathology. Formal diagnosis of triploidy depends on the fetal karyotype. The better the maternal prognosis is, the worst the fetal prognosis is. Postnatal life expectancy is not more than a few weeks. In most cases, maternal associated complications disappear with the molar evacuation. The risk of post molar tumor is discussed. However, good management of triploidy is based on an early diagnosis, before birth if that is possible.