Implementación universal del «consecutive combined test» en el área sur de Sevilla (Hospital Universitario Valme) / Universal implementation of the “Consecutive Combined Test” in the South Seville area (Valme University Hospital)

La universalización debe ser un objetivo en el cribado de cromosomopatía además de lograr una adecuada sensibilidad y una tasa de falsos positivos (F+) del método de cribado aplicado. Objetivos Nos proponemos implementar un cribado de cromosomopatías en el área sur de Sevilla con la característica de universal (cobertura mayor del 90%) y manteniendo la tasa de diagnóstico del 80% para un 5% de F+. Método A nuestras gestantes, entre julio de 2005 y septiembre de 2008, se les oferta un test combinado consecutivo. En los casos de edad gestacional >13 semanas se les aplica un doble test. Resultados Al 95,1%, de las 12.478 gestantes se les oferta un cribado. Al 86,85% de las gestantes se les realiza un test combinado consecutivo y el 6,43% de las gestantes han revocado el cribado. Se han observado 35 cromosomopatías (prevalencia de 0,28%), con una tasa de diagnóstico del 88,5% para un 4,31% de F+. Conclusiones La universalización debe ser un objetivo en el cribado de cromosomopatías además de lograr una adecuada sensibilidad y tasa de F+ (AU)

Universal application should be an aim in chromosomal abnormality screening, in addition to achieving adequate sensitivity and an acceptable false positive rate of the screening method applied. Objectives We aimed to implement universal chromosomal abnormality screening (coverage greater than 90% of pregnancies) in the southern area of Seville and to maintain the rate of diagnosis at 80% and the false-positive rate at 5%.MethodBetween July 2005 and September 2008, chromosomal abnormality screening through the consecutive combined test was offered to pregnant women in the southern area of Seville. The Double Test was used in women accessing screening later than 13 weeks of pregnancy. Results Of 12,478 pregnant women, chromosomal abnormality screening was offered to 95.1%. The consecutive combined test was performed in 86.86% of the pregnancies and screening was rejected by 6.32% of patients. Thirty-five chromosomal abnormalities were detected (a prevalence of 0.28%), of which 31 (88.5%) were diagnosed prenatally. The false-positive rate was 4.31%.ConclusionsUniversal application should be an objective of chromosomal abnormality screening, in addition to achieving adequate sensitivity and an acceptable false-positive rate in the screening method applied (AU)

Influence of hydration on the dynamics of lysozyme.

Quasielastic neutron and light-scattering techniques along with molecular dynamics simulations were employed to study the influence of hydration on the internal dynamics of lysozyme. We identified three major relaxation processes that contribute to the observed dynamics in the picosecond to nanosecond time range: 1), fluctuations of methyl groups; 2), fast picosecond relaxation; and 3), a slow relaxation process. A low-temperature onset of anharmonicity at T approximately 100 K is ascribed to methyl-group dynamics that is not sensitive to hydration level. The increase of hydration level seems to first increase the fast relaxation process and then activate the slow relaxation process at h approximately 0.2. The quasielastic scattering intensity associated with the slow process increases sharply with an increase of hydration to above h approximately 0.2. Activation of the slow process is responsible for the dynamical transition at T approximately 200 K. The dependence of the slow process on hydration correlates with the hydration dependence of the enzymatic activity of lysozyme, whereas the dependence of the fast process seems to correlate with the hydration dependence of hydrogen exchange of lysozyme.

Protein and solvent dynamics: how strongly are they coupled?

Analysis of Raman and neutron scattering spectra of lysozyme demonstrates that the protein dynamics follow the dynamics of the solvents glycerol and trehalose over the entire temperature range measured 100-350 K. The protein's fast conformational fluctuations and low-frequency vibrations and their temperature variations are very sensitive to behavior of the solvents. Our results give insight into previous counterintuitive observations that protein relaxation is stronger in solid trehalose than in liquid glycerol. They also provide insight into the effectiveness of glycerol as a biological cryopreservant.

Structural study of the low-temperature phase of TlH2PO4 at 180 K.

The low-temperature phase of TlH(2)PO(4) has been studied by X-ray diffraction. A structural model is proposed with space group P1. This model is compared with the structure of the antiferroelectric phase of TlD(2)PO(4) at room temperature to analyze the expected isomorphism at low temperature. Given the structural distortion of TlH(2)PO(4), such isomorphism present in the common high-temperature phase is not recovered in this phase. Through the analysis of the displacements of the PO(4) groups there is some evidence that the ordering of the H atoms responsible for the appearance of antiferroelectricity seems to be incomplete. An exhaustive study of the detected ferroelastic domains is also performed.

Superspace description of the structure of the composite crystal urea/n-octane at room temperature.

A structural model for the composite crystal urea/n-octane is proposed. Despite the lack of information from the largely disordered guest substructure, the final model is consistent with the collected diffraction pattern. The use of the superspace approach stresses the composite character of the inclusion compounds and makes easier a unified view of the whole urea/n-alkane family. In particular, a comparison between the octane and heptadecane derivatives shows a common pattern for the origin of the modulation of the guest chains based on the distribution of the NH(2) groups within each tunnel wall.

Average structure of the composite crystal urea/octanedioic acid at room temperature within the superspace formalism.

The average structure of the composite urea/octanedioic acid has been refined using the superspace formalism [superspace group H'3(1)21(00gamma)001;]. Modulation effects seem to be almost negligible. The guest substructure appears to be largely disordered and has been modelled using rigid units occupying 12 equiprobable different orientations inside the urea tunnels. Guest molecules are slightly tilted with respect to the tunnel axis favouring a stronger guest-guest intratunnel interaction.

X-ray diffraction study of the phase transitions of (CH3)4NCdCl3 between 293 and 80 K: a quantitative analysis of the ferroelastic domains distribution below 118 K

X-ray diffraction patterns of [N(CH3)4][CdCl3], tetramethylammonium trichlorocadmate(II), have been investigated in the temperature range 80-293 K, which includes two phase transitions at 118 and 104 K, respectively. The main interest in this compound is to establish the mechanism of the structural phase transitions common to other members of the isostructural family [(CH3)4N][MX3]. It is supposed to be related to the ordering of the organic part together with some small distortion of the inorganic chains. The origin of the order-disorder mechanism would be the orientationally disordered distribution of the tetramethylammonium tetrahedra at room temperature. Maximum Entropy Methods suggest that the most probable distribution of the organic groups can be described through the so-called two-well model, in which one threefold axis of the tetramethylammonium tetrahedron coincides with the crystallographic threefold axis of the structure. Below 118 K the reflections are split. However, the splitting cannot be fully explained by the ferroelastic domains expected to appear after the phase transitions. Recent NMR results [Mulla-Osman et al. (1998). J. Phys. Condensed Matter, 10, 2465-2476] corroborate the existence of more domains than expected from symmetry considerations. A model of ferroelastic domains which is in agreement with both X-ray diffraction diagram and NMR measurements is proposed.

[Cystic angiomatosis of bone with hematologic involvement. Report of a case]. / Angiomatosis quística de los huesos con repercusión hematológica. Presentación de un caso.

A case of cystic angiomatosis of bone without visceral involvement is presented. Lesions were noted in: skull, ribs, pelvis, long bones and phalanges. Besides clinical and radiological findings, the case, associates pancytopenia and coagulation disorders. The possibility of a bone marrow failure due to invasion of marrow by cystic angiomas and localized intravascular coagulation are discussed as cause of hematologic alterations.