A Splice Site Mutation Of The β-spectrin Gene Causing Exon Skipping In Hereditary Elliptocytosis Associated With A Truncated β-spectrin Chain

We studied a French kindred with hereditary elliptocytosis associated with a spectrin variant (spectrin LePuy) containing a β-spectrin chain that is truncated at its C terminus (Dhermy, D., Lecomte, M., Garbarz, M., Bournier, O., Galand, C., Gautero, H., Feo, C., Alloisio, N., Delaunay, J., and Boivin, P. (1982) J. Clin. Invest. 70, 707-715). The structure of the 3′ end of the β-spectrin gene, the region encoding the C terminus of β-spectrin, was determined. Nucleotide sequencing of amplified genomic DNA revealed a mutation at position +4 (A → G) of the 5′ donor consensus splice site of the intron following the third-to-last exon (exon X) in one β-spectrin allele of a heterozygous patient. Agarose gel electrophoresis of polymerase chain reaction-amplified cDNA revealed an extra band of lower molecular weight, suggesting that the short-ened β-spectrin chain of spectrin LePuy arises from aberrant mRNA splicing. Nucleotide sequencing of the shorter cDNA amplification product revealed that the sequences encoding exon X were absent. Southern blotting of cDNA amplification products confirmed this result. The skipping of exon X causes a shift in the normal reading frame resulting in the encoding of a new amino acid sequence at the C terminus of the mutant β-spectrin chain. A new in-frame stop codon is encountered following a single residue of this novel sequence.26623151541515

Comparison of near infrared reflectance analysis of fecal fat, nitrogen and water with conventional methods, and fecal energy content

Comparison of near infrared reflectance analysis of fecal fat, nitrogen and water with conventional methods, and fecal energy content. Neucker AV, Bijleveld CM, Wolthers BG, Swaaneburg JC, Kester AD, Kreel B, Forget PP. Department of Pediatrics,University Hospital Maastricht, 6202 AZ, Maastricht, The Netherlands. [email protected] OBJECTIVES: To evaluate Near-Infrared Analysis (NIRA) method for determining fecal fat, water and nitrogen. DESIGN AND METHODS: The results of fecal fat, water and nitrogen by NIRA were compared with results of van de Kamer and Acid Steatocrit (AS), Dumas and vacuum drying methods for fat, nitrogen and water respectively.Results of fat determining methods were also compared with total fecal energy as obtained by bomb calorimeter. RESULTS: NIRA results correlated significantly (p < 0.001) with standard methods for nitrogen (r = 0.79), fat (r = 0.84 and r = 0.88 for van de Kamer and AS respectively) and water (r = 0.91). The limits of agreement for nitrogen and fat results were too wide for the methods to be used interchangeably. The fecal fat results correlated significantly (p < 0.001) with fecal energy results. CONCLUSION: NIRA may be valuable for monitoring malabsorption but the diagnostic value remains to be determined

Modelling and rapid simulation of multiple red blood cell light scattering

The goal of this work is to develop a computational framework to rapidly simulate the light scattering response of multiple red blood cells. Because the wavelength of visible light (3.8×10−7 m≤λ≤7.2×10−7 m) is approximately an order of magnitude smaller than the diameter of a typical red blood cell scatterer (d≈8×10−6 m), geometric ray-tracing theory is applicable, and can be used to quickly ascertain the amount of optical energy, characterized by the Poynting vector, that is reflected and absorbed by multiple red blood cells. The overall objective is to provide a straightforward approach that can be easily implemented by researchers in the field, using standard desktop computers. Three-dimensional examples are given to illustrate the approach and the results compare quite closely to experiments on blood samples conducted at the Children's Hospital Oakland Research Institute (CHORI)