Posture, blood velocity in common femoral vein, and prophylaxis of venous thromboembolism

Might leg elevation and avoidance of poor postures provide better prophylaxis against venous thromboembolism than heparin or mechanical methods? 12 supine subjects tilted in 3 degrees increments from 6 degrees leg-down to 12 degrees leg-up showed linear increase in mean peak blood velocity and reduction in calibre in the common femoral vein (colour-duplex ultrasound). Between horizontal and 6 degrees leg-up, velocity was increased by 17% and diameter reduced by 14%. A ranking of mean peak velocities in six postures (sitting; standing; trunk raised 35 degrees to legs which were first horizontal and then tilted up 6 degrees; supine, first horizontal then 6 degrees leg-up) showed significant increases in velocity between consecutive positions.     

Curved composite boundary elements for second-order two-dimensional problems

Finite elements with a curved edge often require relatively large numerical effort to form.^1–4 Relatively simple triangular elements with a single curved edge are developed in this paper for second-order, two-dimensional problems. A convex boundary element is formed as a composite of two straight-edged triangles and a circular sector. Application of the convex composite boundary element results in less numerical effort for a comparable error in circular and elliptical domain test problems than the application of straight-edged elements in all cases shown, and in most cases when compared to the curved isoparametric elements. For domains with concave boundaries, the application of straight-edged, concave composite boundary and curved isoparametric elements give comparable accuracies and numerical efforts because of a fortuitous cancellation of error that occurs with straight-edged elements in this case.     

Functional analysis of the fibrinogen-related scabrous gene from Drosophila melanogaster identifies potential effector and stimulatory protein domains

The scabrous (sca) gene encodes a secreted dimeric glycoprotein with putative coiled-coil domains N-terminally and a C-terminal region related to the blood clot protein fibrinogen. Homozygous sca mutants have extra bristle organs and rough eyes. We describe a GAL4-based expression system for testing rescue of the sca mutant phenotype by altered SCA proteins and for misexpression. We find that deletion of the fibrinogen-related domain (FReD) greatly decreases SCA function, confirming the importance of this conserved region. SCA function could not be restored by FReDs from human fibrinogen chain genes. However, proteins lacking any FReD still showed some function in both rescue and misexpression experiments, suggesting that putative effector-binding regions lie outside this domain. Consistent with this, proteins expressing only the FReD had no rescuing activity but were recessive negative; i.e., they enhanced the phenotype of sca mutations but had no phenotype in the presence of a wild-type sca allele. This suggests that the FReD contributes to SCA function by binding to other components of the bristle determination pathway, increasing the activity of the linked N-terminal region.     

Isolation of Vibrio cholerae O1 from aquatic environments and foods in Pernambuco State, Brazil

Gastrointestinal symptoms and fecal frequency following ingestion of yogurt containing 15 g of galacto-oligosaccharides (GOS) per d were observed in 12 healthy volunteers. The effect of GOS on intestinal microflora was also studied in six volunteers. Defecation frequency increased during the administration period, but gastrointestinal symptoms, especially flatulence, also increased. The level of fecal bifidobacteria did not increase by the yogurt intake, but a significant increase was observed in the fecal bacteria growing on MRS media. The results indicate that dietary GOS increase gastrointestinal symptoms and fecal frequency in normal adults and have an effect on intestinal microecosystem.     

Metabolic delivery of ketone groups to sialic acid residues. Application To cell surface glycoform engineering

The development of chemical strategies for decorating cells with defined carbohydrate epitopes would greatly facilitate studies of carbohydrate-mediated cell surface interactions. This report describes a general strategy for engineering the display of chemically defined oligosaccharides on cell surfaces that combines the concepts of metabolic engineering and selective chemical reactivity. Using a recently described method (Mahal, L. K., Yarema, K. J., and Bertozzi, C. R. (1997) Science 276, 1125-1128), we delivered a uniquely reactive ketone group to endogenous cell surface sialic acid residues by treating cells with the ketone-bearing metabolic precursor N-levulinoylmannosamine (ManLev). The ketone undergoes highly selective condensation reactions with complementary nucleophiles such as aminooxy and hydrazide groups. The detailed quantitative parameters of ManLev metabolism in human and nonhuman-derived cell lines were determined to establish a foundation for the modification of cell surfaces with novel epitopes at defined cell-surface densities. Ketones within the glycoconjugates on ManLev-treated cells were then reacted with synthetic aminooxy and hydrazide-functionalized carbohydrates. The remodeled cells were endowed with novel lectin binding profiles as determined by flow cytometry analysis. The simplicity and generality of this method make it well suited for use in the study of carbohydrate-mediated cell surface interactions.     

Homograft tympanic membrane myringoplasty

During a six-year period, homograft tympanic membranes have been used successfully for myringoplasty or tympanoplasty in 85% of 175 cases. This percentage is not as high as might be expected with fascia, and the homografts have not been as dependable in the wet, draining ear. However, the results do show that the homograft is an acceptable grafting material. The eardrums are not suggested as substitutes for fascia, but should be available for difficult cases. Their use is indicated in large or total defects to restore the natural anatomical conical shape of the eardrum, particularly in congenital atresia. The prime indication for their use is a missing malleus, and the malleus handle can be included within the transplant. The eardrum's rigid properties and the possibility of inclusion of ossicles make the homografts valuable in reconstruction of the old mastoid cavity.     

An analysis of the value of additional diagnostic procedures

When several diagnostic procedures are performed on a patient, the probability of his having or not having a specific ailment will change as the result of each procedure is known. This paper describes how such a change is readily calculated using Bayes' theorem. Information theory is also used to find the increment in information from each successive test. Numerical estimates are made using data pertinent to lung X-ray examinations. Finally, some implications for diagnostic examinations in general are drawn.