[Prevention and treatment of dento-maxillary discrepancy]. / Prévention et traitement de la dysharmonie dento-maxillaire.

The many clinical and radiological signs of arch length discrepancy simplify the practitioner's task of diagnosing it early. When they need to deal with insufficient room in the dental arch, orthodontists have available to them a large variety of therapeutic possibilities that require relatively little cooperation from young patients and that often work quickly to correct beginning malocclusions in the mixed dentition or that prevent them from worsening. Orthodontists decide whether to use space maintainers, increase arch length, or embark on a program of serial extraction depending upon the type of disorder, its severity, and its etiology. The principle objectives of early treatment in arch length discrepancy cases are to re-establish a balanced occlusion and to reduce the duration and the complexity of definitive treatment in the adult dentition.

[Type I interferons]. / Les interférons de type I.

Type I interferons (IFNa/b) form a family of related cytokines that include INFa, b, e/s, j, x (human) and limitin (mouse). These cytokines exert a potent antiviral activity, control cell proliferation and modulate the immune response. They are used in the fight against viral infections, tumors, and multiple sclerosis. Expression of IFNs is typically induced by viral infections. Cells express cytoplasmic helicases as well as endosomial toll-like receptors acting as sensors to detect endogenous and exogenous viral infections, respectively. Signal transduction from these sensors induces the transcription of IFN genes. IFNs are secreted and bind to a cell surface receptor expressed by most cells of the organism. Upon receptor binding, IFNs induce the transcription of hundreds of genes whose products exert antiviral, antiproliferative and immunomodulatory functions. Antiviral activity of IFNs is so potent that most (if not all) viruses developed strategies to antagonize the IFN response.

Isolation and quantitation of zeins in waxy and amylose-extender and wild flint and dent maize endosperm using a new solvent sequence for protein extraction.

Protein distribution in endosperm of maize grains differing by their texture, flint or dent, and by their genotype, wild or waxy or amylose-extender, was examined by the successive use of 0.5 M NaCl, 0.5 M NaCl plus 0.6% 2-mercaptoethanol (2ME) at neutral and then alkaline pH, and 55% 2-propanol plus 0.6% 2ME as extractants. Proteins extracted in the presence of 2ME were characterized by their size polymorphism and amino acid composition. Proteins isolated with NaCl plus 2ME at neutral pH corresponded with a mixture of gamma-zein (27 kDa) and glutelin-like proteins. Proteins isolated with NaCl plus 2ME at pH 10 were a mixture of gamma-zeins (27 and 16 kDa) and beta-zeins (14 kDa). Alcohol-soluble proteins consisted of alpha-, beta-, and delta-zeins, alpha subunits being predominant. Zein quantitation was improved by weighing the nitrogen percentage of extracts by their zein content, as estimated from the data on amino acid composition. The data reported by Wolf et al. (Cereal Chem. 1975, 52, 765) were integrated to the results of this work to suggest the occurrence of an inverse correlation between amylose in starch and zeins in proteins.

Tryptophan content of foods and feeds. Conditions for a reliable quantitation.

A procedure for the quantitative determination of tryptophan from complex material was developed. It involved the hydrolysis of samples in the presence of baryta. Data were presented, revealing its quantitativeness and pointing out its efficiency when it was compared with diverse methods developed by other laboratories as a part of collaborative studies. The influence of the way of treating and heating of (sample+baryta) mixture upon tryptophan recovery was also investigated. The placement of (sample+baryta) mixture in an autoclave, when water was boiling, or the careful deaeration of the mixture when it was heated in an oven was essential for quantitative results. These specific conditions can be explained by differences of the protein solvatation, related to the way by which the (sample+baryta) mixture was heated.

The tryptophan content in protein of cereal grains and legume seeds as a function of nitrogen content. A reappraisal of tryptophan score.

UNLABELLED: The tryptophan content ([Trp]) in the dry matter (DM) of wheat, maize, barley, sorghum, rice, pearl millet grains, pea and broad bean seeds is evaluated from samples, with various nitrogen contents ([N]DM) and genotypes, using a procedure that has been shown to be strictly quantitative. The determination of linear correlations between [Trp]DM and [N]DM, and between the tryptophan content in protein ([Trp]N) and [N]DM or 1/[N]DM for every species leads to the following observations: (1) [Trp]DM and [N]DM are linearly related. The data show that previous reports of similar relationships underestimate tryptophan by 10 +/- 5% owing to tryptophan degradation during alkaline hydrolysis preparatory to analysis; (2) the linear correlations between [Trp]N and 1/[N]DM, resulting from linear relationships [Trp]DM and [N]DM display coefficients of determination (r2) far lower than 1 and similar to those found for linear correlations between [Trp]N and [N]DM; (3) [Trp]N increases with [N]DM increasing for rice and pearl millet while it decreases for all other species. IN CONCLUSION: (1) linear relationships between tryptophan and nitrogen have a low predictive value; (2) the nutritional score of tryptophan of foods and feeds, as calculated from the determination of tryptophan using a procedure involving alkaline hydrolysis, is generally underestimated by 10%.

HPLC determination of tryptophan in foodstuffs using barium hydroxide hydrolysis at 140°C.

Hydrolysis of samples of food and feedstuffs with 2.7 N Ba(OH)2 at 140°C for 4 h was tested for the recovery of tryptophan. On the basis of 100% yield for the tryptophan content, corresponding to samples determined after 16h-hydrolysis at 125°C, the recovery averaged 98.7 ± 0.9% SD or 99.4 ± 2% depending on how the bulk or aliquot of hydrolysate was analysed (conventional or simplified procedure). Tryptophan can be assayed by high performance liquid chromatography and fluorescence detection within 8h, 4h-hydrolysis at 140°C and a simplified procedure.

High-performance liquid chromatography and ultraviolet spectrophotometry for quantitation of tryptophan in barytic hydrolysates.

A procedure for quantitation of tryptophan in feedstuffs is described. It is based on barytic hydrolysis of material at 125 degrees C for 16 h, acidification of hydrolysate to pH 3 with HCl, high-performance liquid chromatography on Nova Pak C18 (Waters Assoc.), and spectrophotometric determination of tryptophan at 280 nm. The recovery of tryptophan from lysozyme added to samples ranges from 98.7 to 100%.