Hierarchical decision model for in vitro bilirubin content prediction from absorption spectrum of whole blood.

Significance: Bilirubin forms by the breakdown of heme proteins in the liver, but a newborn's sluggish liver can lead to elevated serum bilirubin levels that cross the blood-brain barrier and result in kernicterus. Earlier studies have used the 400 to 500 nm optical wavelength range to characterize the bilirubin content. There is not a universally established correlation among other wavelengths and the amount of bilirubin in clinical whole blood samples. Aim: We demonstrated that the amount of bilirubin could be quantified with ∼82% accuracy in a label-free, self-referenced manner using only a few wavelengths, viz. 468, 492, 500, 560, 605, 645, 660, and 675 nm, wherein band-averaged absorption measurements are used. Approach: We addressed the above problem by conducting a preliminary study containing 50 neonates through an absorption spectrum measurement of whole blood in 3 to 5 µl samples from the neonates. We constructed a hierarchical decision method that first grossly divides the 30 neonates of the training set into <10 mg/dl and ≥10 mg/dl bilirubin level cohorts. A subsequent boundary condition further divides the ≥10 mg/dl group into two >15 mg/dl and ≤15 mg/dl bilirubin level cohorts. A finer measure later predicted the bilirubin content of each of these groups as low (<10 mg/dl), medium (10 to 15 mg/dl), and high (>15 mg/dl). Results: Using this hierarchical decision model statistical approach, we quantified the amount of bilirubin in the 20 testing set samples with 82% accuracy. Conclusions: We formulated a biostatistical model in which we automated the spectrometric determination of total bilirubin in the whole blood for patients of neonatal hyperbilirubinemia.

Weighted morphology: a new approach towards phylogenetic assessment of Nostocales (Cyanobacteria).

The classification of order Nostocales (Cyanobacteria) and inter relationships of morphologically similar taxa is still debatable due to ever changing morphological features. No attempt has been made to improve the morphological taxonomy despite the fact that it is the morphology that represents the totality of genes. To test the validity of morphological taxonomy and fine tune the phylogenetic relationships within the order Nostocales a new weighted morphology approach was applied by using 76 isolates and their 16S rRNA gene sequences. Further, the study was extended with morphological data set of the remaining 232 taxa for which no molecular data are yet available. Trichome aggregation, heterocyst shape, and akinete shape are suggested as important and stable features for identification. At 30% weight assignment to the selected morphological characters, morphological taxonomy found 36% compatible with 16S tree. Adding weight to the morphological characters considerably improved the congruence between the morphology and 16S rRNA-based phylogenetic trees of the order Nostocales. When the weighting procedure was extended to all the Nostocalean members irrespective of molecular data availability, it was found that Nostoc sphaericum and Nostoc microscopicum closely assembled in a single clade. Closer arrangement of Aulosira and Nodularia represent the subfamily aulosirae (Bornet and Flahault Ann Sci Nat Bot 7:223-224, 1888) while taxonomic affiliation of Cylindrospermum with Nostoc, Anabaena, and Raphidiopsis representing the subfamily anabaenae (Bornet and Flahault Ann Sci Nat Bot 7:223-224, 1888) was resolved.