[Benefits and limitations of geriatric dysphagia screening tools]. / Intérêt et limites des outils de dépistage de la dysphagie en gériatrie.

This prospective study aims to evaluate both benefits and limitations of dysphagia screening tools (DePippo, EAT10, V-VST, the IOPI tongue-strength assessment) used in a geriatric unit. Among the 102 patients under study, 47 showed a dysphagia diagnosed by full logopedic examination. The sensitivity and the specificity of the screening tools were, respectively, 31,9 % and 83,6 % for EAT10, 86,9 % and 52,7 % for the V-VST and 76,6 % and 65,0 % for the DePippo test. Regarding the posterior tongue strength assessment, the threshold value of 31kPA showed an 77,3 % sensitivity and a 52,7 % specificity. Given the results obtained from the above-mentioned screening tools and their practical application limitations, the DePippo test appears to be the most convenient for a day-to-day geriatric utilization. Finally, this study outlines the necessity of confirming, in a larger sample, the reproducibility of the DePippo test as well as the interest of measuring the tongue strength among frail older people.

L'objectif de cette étude prospective était d'évaluer l'intérêt et les limites d'outils de dépistage de la dysphagie (DePippo, EAT10, V-VST, mesure de la force de langue par IOPI) lors de leur utilisation au sein d'un service de gériatrie. Parmi les 102 patients inclus, 47 présentaient une dysphagie relevée par une évaluation logopédique complète. La sensibilité et la spécificité des tests de dépistage ont été respectivement de 31,9 % et 83,6 % pour l'EAT10, de 86,9 % et 52,7 % pour le V-VST, et de 76,6 % et 65,0 % pour le test de DePippo. Concernant la force postérieure de la langue, la valeur seuil minimale de 31 kPa présentait une sensibilité de 77,3 % et une spécificité de 52,7 %. Bien que moins sensible que le V-VST, le test de DePippo (test à l'eau) est plus largement applicable aux patients fragiles hospitalisés en gériatrie. De plus, cette étude met en lumière la nécessité de préciser, au sein d'un échantillon plus large, la reproductibilité du test de DePippo et l'intérêt de la mesure de la force de langue. En conclusion, et sous réserve de son taux de reproductibilité à préciser, le test de DePippo apparaît, actuellement, être l'outil de dépistage le plus adapté à une utilisation en gériatrie.

[Swallowing disorders in elderly patients: a multidisciplinary approach]. / Personnes âgées et troubles de la déglutition: une approche pluridisciplinaire.

Presbyphagia represents the physiological aging of swallowing function. It predisposes to difficulty in swallowing, namely dysphagia, which is of high incidence in the elderly population. The consequences of dysphagia are multiple and always a tragedy for the patient; they consist of aspiration pneumonia, malnutrition, dehydration, social isolation, and death. The diagnosis is difficult and is based on the medical history and clinical examination, associated with diagnostic tests. Its management is multidisciplinary, leaving only little room for medications or surgery.

[Swallowing disorders in the elderly: an underestimated problem]. / Les troubles de la déglutition du sujet âgé: un problème trop souvent sous-estimé.

Swallowing disorders are frequently observed in the elderly and often accompany an organic pathology. Such disorders may quickly constitute a threat for life: inhalation syndrome, pulmonary infection, undernutrition, dehydration. Diagnosing swallowing disorders is difficult and relies on anamnesis, clinical examination combined with paraclinical investigations. However, there is little place for medicinal or surgical treatment, their management being integral and multidisciplinary.

The isolation of anti-gum arabic antibodies by affinity chromatography.

Antibodies directed at gum arabic have been induced in rabbits immunized with gum arabic in Freund's complete adjuvant. These antibodies have been isolated in pure form by affinity chromatography on AH-Sepharose 4B containing gum arabic ligands. Oxidation of the susceptable carbohydrate residues of gum arabic with periodate or reduction of the glucuronic acid moieties with carbodiimide and borohydride converted the polysaccharide to products which no longer yielded precipitin reactions with the antibodies. The antibodies are therefore anti-carbohydrate antibodies with specificity for certain carbohydrate units of the gum arabic. Results of chemical modification and inhibition experiments indicate that 4-alpha-L-arabinofuranosyl-D-glucuronic acid units of the polysaccharide are the major immunodeterminant groups.

Investigations on gel forming media for use in low gravity bioseparations research.

Microgravity research includes investigations designed to gain insight on methods of separating living cells. During a typical separation certain real-time measurements can be made by optical methods, but some materials must also be subjected to subsequent analyses, sometimes including cultivation of the separated cells. In the absence of on-orbit analytical or fraction collecting procedures, some means is required to "capture" cells after separation. The use of solutions that form gels was therefore investigated as a means of maintaining cells and/or macromolecules in the separated state after two types of simple ground-based experiments. Microgravity electrophoresis experiments were simulated by separating model cell types (rat, chicken, human and rabbit erythrocytes) in a vertical density gradient containing low-conductivity buffer, 1.7%-6.5% Ficoll, 6.8-5.0% sucrose, and 1% SeaPrep low-melting temperature agarose and demonstrating that, upon cooling, a gel formed in the column, and cells could be captured in the positions to which they had migrated. Two-phase extraction experiments were simulated by choosing two-polymer solutions in which phase separation occurs in normal saline at temperatures compatible with cell viability and in which one or both phases form a gel upon cooling. Suitable polymers included commercial agaroses (1-2%), maltodextrin (5-7%) and gelatin (5-20%).

[A new method to study behavioral categories and systems of interaction of young children. Initial data]. / Une nouvelle méthode pour l'étude des organisateurs de comportements et des systèmes d'interaction du jeune enfant. Les premières données.

In the first part of this paper we report on a new method we have developed for the study of the genesis and regulations of the behavior of infants in interactive situations. Detailed information is given on the following aspects: 1. The technical characteristics of the device that allows the infants to be seated in an upright position; 2. The different periods of the experimental procedure; 3. The method used for analyzing the behavioral data. As infants were video-taped without any interruption (real-time record), the behavioral data were analysed in two different ways: A. Macroscopic analyses were carried out using 84 items and 12 categories of behavior. These analyses allowed us to measure the temporal evolution of a limited set of easily recognized behaviors from one experimental period to the next and one experimental session to the next at one-week time intervals; B. Microscopic analyses were carried out with a special software program (THEME) using 222 items divided among 14 categories of behavior. This program was created by Magnusson. It allows the worker to search for significant patterns in sequential events which are recorded in real time, i.e. intra-individual behavioral structure as well as interindividual relationship (interaction). Information is given on the theoretical model and the pattern identification method. The first data can be thus summarized: 1. Four month old infants show a high level competence in their visual attention span in relation to each other; 2. They appear to have varied and complex behavior and interaction processes; 3. Each child has his or her own behavior dynamics throughout each experimental session and from one period to the next; 4. There are some special relationships between infant-infant interactions and the modalities of interaction between each infant and its mother; 5. Periodical behavioral "outbursts" are observed, which might in themselves constitute organizers of behavior; 6. It also makes clear the existence and structure of significant intra- and inter-individual behavioral patterns some of which are particularly complex (patterns are defined as significant connections between two items at least, within a critical time interval, calculated by THEME); 7. It reveals the function of these patterns in mutual adjustment processes between both infants throughout the experimental session.

Electrostatic forces at helix-coil boundaries in DNA.

The Tm of internal loop-forming (dA.dT)N domains in pBR322 DNA has been measured over a tenfold range of [Na+]. The slopes SN = dTm/d log [Na+] are linear and decrease in magnitude with decreasing loop size N, signaling a reduction in Na+ released during the transition of these domains to the coil state. Values of SN decrease linearly with increasing N-1 in accordance with the expectation of a simple model for the occurrence of a gradient of long-range electrostatic forces at helix-coil boundaries, and extrapolate almost precisely to the value of S infinity observed for (dA.dT) infinity. These results indicate (1) less counterion is released per phosphate residue from the finite loop than from the infinite-sized loop, and (2) the difference in binding is constant for each boundary formed and independent of the size of the loop within the range examined: approximately 350 base pair (bp) greater than N greater than 71 bp. The slope of the dependence of SN on N-1 indicates the region of higher charge density at the boundary extends at least 18 A into the coil and probably 40-50 A before dropping to a value characteristic of the unperturbed coil. The free energy for excess counterion binding at boundaries can be expressed by -delta G/RT = 10.47 log[Na+] + 5.234 When the loop entropy function in a statistical mechanical algorithm for the dissociation of DNA is weighted by this quantity, calculated Tm are seen to vary by only +/- 0.09 degrees C from observed.

Stacking energies in DNA.

Variations in base mono- and dipoles result in variations in stacking energies for the 10 unique neighbor pairs in DNA. Stacking energies for pair M on N, expressed as TMN, were derived by matrix decomposition of a large set of linear algebraic expressions relating the measured Tm for subtransitions emanating from large polymeric DNAs, and the fractional neighbor frequencies, fMN, for the domains responsible for the transitions, Tm = sigma fMNTMN. Tm were determined for subtransitions that dissociate in approximately all-or-none fashion in high resolution melting profiles of partially deleted and recombinant forms of pBR322 DNA. Three different analytical maneuvers were undertaken to resolve subtransitions: site-specific cleavage of domains; deletion of domains; and addition of domains. Three dozen domains of widely divergent, quasi-random neighbor frequencies were identified and assigned, resulting in a unique set of values for TMN with standard deviation, sigma = +/- 0.23 degree C. The average difference between calculated and experimental Tm for domains is only +/- 0.17 degree C, indicating that the thermodynamic properties of these domains are not in any way unusual. Assuming delta S to be constant for all pairs, the corresponding delta HMN are found to have a precision of +/- 10 calories.mol-1 and an accuracy of +/- 606 calories.mol-1. TMN used to calculate melting curves by statistical mechanical analysis of sequences of the different plasmid specimens in this study were in quantitative agreement with observed curves for most sequences. These TMN differ significantly from those determined previously and also correlate poorly with values determined by quantum chemical analysis. Stabilities of neighbor pairs, expressed as the difference in free energy between that for a given pair (MN) and that for the average of like pairs (M, N), depend on the relationship of stacked purines and pyrimidines as follows. delta delta Gpu-py(-466 cal) greater than delta delta Gpu-pu(+52 cal) greater than delta delta Gpy-pu(+335 cal) Differences between experimental Tm and Tm calculated with TMN for the isolated neighbor pairs in the B-conformation are useful in the identification of altered structures and unusual modes of dissociation of helixes. A significantly higher Tm is observed for the highly biased repeated sequence synthetic helixes dA.dT, d(AGC).d(GCT), and d(GAT).d(ATC), reflecting auxiliary sources of stability such as bifurcated hydrogen bonds and/or altered structures for these helixes.

Thermal stability of DNA.

Tij and Delta Hij for stacking of pair i upon j in DNA have been obtained over the range 0.034-0.114 M Na+from high-resolution melting curves of well-behaved synthetic tandemly repeating inserts in recombinant pN/MCS plasmids. Results are consistent with neighbor-pair thermodynamic additivity, where the stability constant, sij , for different domains of length N depend quantitatively on the product of stability constants for each individual pair in domains, sijN . Unit transition enthalpies with average errors less than +/-5%, were determined by analysis of two-state equilibria associated with the melting of internal domains and verified from variations of Tij with [Na+]. Enthalpies increase with Tij , in close agreement with the empirical function: Delta Hij = 52.78@ Tij - 9489, and in parallel with a smaller increase in Delta Sij . Delta Hij and Delta Sij are in good agreement with the results of an extensive compilation of published Delta Hcal and Delta Scal for synthetic and natural DNAs. Neighbor-pair additivity was also observed for (dA@dT)-tracts at melting temperatures; no evidence could be detected of the familiar and unusual structural features that characterize tracts at lower temperatures. The energetic effects of loops were determined from the melting behavior of repeating inserts installed between (G+C)-rich barrier domains in the pN/MCS plasmids. A unique set of values for the cooperativity, loop exponent and stiffness parameters were found applicable to internal domains of all sizes and sequences. Statistical mechanical curves calculated with values of Tij([Na+]) , Delta Hij and these loop parameters are in good agreement with observation.

Thermodynamic effects of formamide on DNA stability.

Formamide lowers melting temperatures (Tm) of DNAs linearly by 2.4-2.9 degrees C/mole of formamide (C(F)) depending on the (G+C) composition, helix conformation and state of hydration. The inherent cooperativity of melting is unaffected by the denaturant. dTm/dC(F)for 11 plasmid domains of 0.23 < (G+C)<0.71 generally fit to a linear dependence on (G+C)-content, which, however, is consistent with a (G+C)-independent alteration in the apparent equilibrium constant for thermally induced helix <--> coil transitions. Results indicate that formamide has a destabilizing effect on the helical state, and that sequence-dependent variations in hydration patterns are primarily responsible for small variations in sensitivity to the denaturant. The average unit transition enthalpy delta H(m)[see text for complete expression], exhibits a biphasic dependence on formamide concentration. The initial drop of -0.8 kcal/mol bp at low formamide concentrations is attributable to a delta delta H(m)[see text for complete expression], for exchange of solvent in the vicinity of the helix: displacement by formamide of weakly bound hydrate or counterion. The phenomenological effects are equivalent to lowering the bulk counterion concentration. Poly(dA.dT) exhibits a much lower sensitivity to formamide, due to the specific pattern of tightly bound, immobilized water bridges that buttress the helix from within the narrow minor groove. Tracts of three (A.T)-pairs behave normally, but tracts of six exhibit the same level of reduced sensitivity as the polymer, suggesting a conformational shift as tracts are elongated beyond some critical length [McCarthy J.G. and Rich,A. (1991) Nucleic Acids Res. 19, 3421-3429].

High-resolution calorimetric and optical melting profiles of DNA plasmids: resolving contributions from intrinsic melting domains and specifically designed inserts.

We demonstrate that differential scanning calorimetry (DSC) can be used to yield high-resolution melting profiles for DNA plasmids that agree in all major features with the corresponding plasmid melting profiles derived using more traditional optical techniques. We further demonstrate that by combining information derived from both calorimetric and optical melting profiles one can glean insights that are unavailable from either melting curve alone. By using both optical and calorimetric observables, we show how one can resolve, identify, and measure the thermodynamic properties of particular sequences/domains of interest within a plasmid. We also show that complementary DSC and optical melting studies on plasmids with and without specifically designed inserts can provide fundamental advantages over the corresponding melting studies on other model system constructs for thermodynamically characterizing nucleic acid sequences/structures.

The acrosome reaction response assay: a new way to identify patients in whom pentoxifylline would improve the human follicular fluid-induced acrosome reaction.

The effect of pentoxifylline on the spontaneous and follicular fluid (hFF)-induced acrosome reaction (AR) was studied in an attempt to identify those patients who would benefit from the use of pentoxifylline as an AR-stimulating agent. Pentoxifylline (1 mg/ml) produced no significant increase over spontaneous AR at any of the time points studied (60 min: 6.2% +/- 2.0 spontaneous AR vs 7.4% +/- 2.0 pentoxifylline AR; 120 min: 7.1% +/- 1.6 spontaneous vs 9.0% +/- 2.5 pentoxifylline; 180 min: 7.0% +/- 1.8 spontaneous vs 10.9% +/- 4.0 pentoxifylline, n = 6). On the other hand, hFF produced a significant increase in AR (6.9% spontaneous AR vs 11.2% hFF AR, p < 0.001, n = 39) and this effect was enhanced by pre-incubation with pentoxifylline (15.0% pentoxifylline + hFF AR vs 11.2% hFF AR, p < 0.001). There were no differences in percentage AR induced by hFF or pentoxifylline + hFF between patients with normal (n = 16) and abnormal (n = 25) semen samples. Individual analysis of the effects of hFF and pentoxifylline + hFF on AR showed great variability between patients and enabled us to classify them into four categories: inducible-responder (15%), non-inducible-responder (23%), inducible-non-responder (41%) and non-inducible-non-responder (21%). An induction index (II) (induction produced by hFF divided by spontaneous AR) and a response index (RI) (induction produced by pentoxifylline + hFF divided by hFF) were calculated for each sample. Patients previously classified as inducible exhibited an II > 0.30 and patients previously classified as responders showed an RI > 0.26. There was no correlation between II and RI values (Spearman, r = -0.185, p = 1). Our results show that pentoxifylline is an enhancer of the induced AR only in some patients. We propose an 'AR response assay' to identify responder patients and thus enable rational use of this drug.

Statistical mechanical simulation of polymeric DNA melting with MELTSIM.

MOTIVATION: MELTSIM is a windows-based statistical mechanical program for simulating melting curves of DNAs of known sequence and genomic dimensions under different conditions of ionic strength with great accuracy. The program is useful for mapping variations of base compositions of sequences, conducting studies of denaturation, establishing appropriate conditions for hybridization and renaturation, determinations of sequence complexity, and sequence divergence. RESULTS: Good agreement is achieved between experimental and calculated melting curves of plasmid, bacterial, yeast and human DNAs. Denaturation maps that accompany the calculated curves indicate non-coding regions have a significantly lower (G+C) composition than coding regions in all species examined. Curves of partially sequenced human DNA suggest the current database may be heavily biased with coding regions, and excluding large (A+T)-rich elements. AVAILABILITY: MELTSIM 1.0 is available at: //www.uml.edu/Dept/Chem/UMLBIC/Apps/MEL TSIM/MELTSIM-1.0-Win/meltsim. zip. Melting curve plots in this paper were made with GNUPLOT 3.5, available at: http://www.cs.dartmouth.edu/gnuplot_inf o.html Contact : blake@maine.maine.edu;

Implicancias del sistema GH (Growth Hormone) IGF-I (Insuline like growth factor 1) E IGFBP-3 (Insuline like growth factor binding protein-3) sobre la competencia ovocitaria en fertilización in vitro / Implicating of GH system, IGF-1 and IGFBP-3 on oocyte competence at in vitro fertilization

Objetivos: Investigar la asociación entre los niveles de GH - IGF-I -IGFBP-3 y progesterona (Pg) en líquido folicular humano y el nº de ovocitos reclutados, su madurez, fertilización y clivaje in vitro. Material y Métodos: Diseño: Observacional, analítico transversal. Se estudió el fluido folicular de 74 folículos, cada uno conteniendo un ovocito, en 17 pacientes, luego de su aspiración para FIV-ET, registrándose para cada ovocito su clasificación y evolución en cultivo. Se midieron los niveles de GH, IGF-I, IGFBP-3 y Pg por RIA. Los valores se expresan en Md (rango intercuartílico). Resultados: El grupo de pacientes de baja respuesta folicular (ovocitos < ó=3) presentó menores niveles intrafoliculares de GH y Pg que las normorespondedoras. [0,7 (0,34) vs 1,25 (0,87) ng/ml, p < 0,01; 6.775,1 (4.225,5) vs 10.180,0 (6.700,5) p < 0,01, respectivamente]. Las concentraciones intrafoliculares de GH e IGF-I fueron significativamente mayores en el grupo que recibió análogos GnRH [1,26 (1,12) vs 0,56 (0,74) ng/ml, p < 0,002 y 0,62 (0,3) vs 0,42 (0,34) U/ml, p < 0,03]. La fertilización ovocitaria y clivaje positivos se asociaron a mayores concentraciones de GH [1,26-(1,1) vs 0,56 (0,98) ng/ml, p < 0,02], IGF-1 [0,63 (0,28) vs 0,51 (0,3), p < 0,05] e IGFBP-3 [2,8 (1,4) vs 1,89 (1:91) p < 0,01]. Conclusiones: Los resultados observados sugieren: 1) Existiría una asociación entre la baja respuesta ovocitaria y menores concentraciones intrafoliculares de GH y Pg. 2) La administración de análogos modularía positivamente el sistema GH - IGF-I durante la foliculogenesis. 3) A su vez la exposición a mayores niveles de GH e IGF-I se vincularía a una myor habilidad del ovocito para fertilizar y clivar in vitro