Processability of cottonseed proteins into biodegradable materials.

The manufacture of biodegradable materials from agricultural sources is a real challenge, because of environmental concerns and the need to make full use of resources. Cottonseed is an important protein source that could be used in nonfood applications, as a substitute for synthetic polymers. For the first time, the viscoelastic behavior of cottonseed protein isolate (CPI), plasticized with glycerol, was characterized in order to determine the temperature range within which cottonseed protein-based materials can be formed by extrusion or thermomolding. Research involved three main techniques: dynamic mechanical analysis to study the alpha protein relaxation associated with glass transition, as a function of plasticization by glycerol; DSC analysis to determine the effect of glycerol content on the protein denaturation and degradation temperatures; and ATG-TG/FTIR to characterize the protein degradation. The results indicated that cottonseed proteins are thermoplastics with a T(g) ranging from 80 to 200 degrees C when the glycerol content varies from 0% to 40% (w/w, dry basis). The proteins' thermal denaturation temperature increased from 141 (without glycerol) to 195 degrees C in the presence of 40% (w/w) glycerol. Protein degradation occurred at 230 degrees C irrespective of glycerol content, with the release of a variety of compounds. Glycerol acts as a plasticizer and thermal stabilizer of the proteins and increases the range of temperatures (80-175 degrees C) at which the material can be processed.

[Osteogenesis imperfecta. Reflections after the prenatal diagnosis of 2 cases]. / L'ostéogenèse imparfaite. Réflexions sur le diagnostic prénatal (à propos de deux cas).

The authors report two cases of prenatal diagnosis of osteogenesis imperfecta (OI) of type II according to the classification of Sillence. When dwarfism had been discovered with deformities, fractures and low bone density, the diagnosis was made in one case at 24 and the second at 20 weeks of amenorrhoea. A recent review of the literature shows that the ideas concerning OI have changed markedly recently. All agree that within the framework of classification of diseases that there is a single entity. A dominant autosome genetic transmission is increasingly considered to be the cause for all forms of the condition. The physiopathology of collagen makes it easier to understand why these should be clinical forms. The ability to localise deleterious genes by using molecular biology makes it likely a very early antenatal diagnosis will be possible. All the same, this optimism has to be tempered with the frequent discovery in this illness of mosaicism which still leaves a large place for ultrasound.

[Prenatal diagnosis of camptomelic dysplasia]. / Un diagnostic anténatal de dysplasie campomélique.

A case of antenatal diagnosis of campomelic dwarfism is reported. The diagnosis was established because of polyhydramnios at 37 weeks of amenorrhoea allowing the discovery through ultrasonography of an uretreral dilatation along with dwarfism. The X-Rays of the uterine contents established the diagnosis. The possibility of the antenatal diagnosis is considered before 20 weeks with an ultrasonography where limbs are systematically measured. As recessive autosomic recession is likely, research must above all be undertaken into past records. Amniocentesis at 16 weeks of amenorrhoea would make it possible to establish the diagnosis if the chromosome type is XY with weak amniotic androgens. Often in this type of anomaly it is difficult to differentiate the sexes.