Individualized body geometry correction factor (KB) for use when predicting body composition from bioimpedance spectroscopy

OBJECTIVE

Prediction of body composition from bioimpedance spectroscopy (BIS) measurements using mixture theory-based biophysical modelling invokes a factor (K_B) to account for differing body geometry (or proportions) between individuals. To date, a single constant value is commonly used. The aim of this study was to investigate variation in KB across individuals and to develop a procedure for estimating an individualized K_Bvalue.

APPROACH

Publicly available body dimension data, primarily from the garment industry, were used to calculate K_Bvalues for individuals of varying body sizes across the life-span. The 3-D surface relationship between weight, height and K_B, was determined and used to create look-up tables to enable estimation of K_Bin individuals based on height and weight. The utility of the proposed method was assessed by comparing body composition predictions from BIS using either a constant K_Bvalue or the individualized value.

RESULTS

Computed KB values were well fitted to height and weight by a 3-D surface (R2 = 0.988). Body composition was predicted more accurately compared to reference methods when using individualized K_Bthan a constant value in infants and children but improvement in prediction was less in adults particularly those with high body mass index.

SIGNIFICANCE

Prediction of body composition from BIS and mixture theory is improved by using an individualized body proportion factor in those of small body habitus, e.g. children. Improvement is small in adults or non-existent in those of large body size. Further improvements may be possible by incorporating a factor to account for trunk size, i.e., waist circumference.

Molecular cloning and characterization of SL3: a stem cell-specific SL RNA from the planarian Schmidtea mediterranea

Spliced leader (SL) trans-splicing is a biological phenomenon, common among many metazoan taxa, consisting in the transfer of a short leader sequence from a small SL RNA to the 5' end of a subset of pre-mRNAs. While knowledge of the biochemical mechanisms driving this process has accumulated over the years, the functional consequences of such post-transcriptional event at the organismal level remain unclear. In addition, the fact that functional analyses have been undertaken mainly in trypanosomes and nematodes leaves a somehow fragmented picture of the possible biological significance and evolution of SL trans-splicing in eukaryotes. Here, we analyzed the spatial expression of SL RNAs in the planarian flatworm Schmidtea mediterranea, with the goal of identifying novel developmental paradigms for the study of trans-splicing in metazoans. Besides the previously identified SL1 and SL2, S. mediterranea expresses a third SL RNA described here as SL3. While, SL1 and SL2 are collectively expressed in a broad range of planarian cell types, SL3 is highly enriched in a subset of the planarian stem cells engaged in regenerative responses. Our findings provide new opportunities to study how trans-splicing may regulate the phenotype of a cell.

Phenylalanine hydroxylase deficiency in the Slovak population: genotype-phenotype correlations and genotype-based predictions of BH4-responsiveness

We investigated the mutation spectrum of the phenylalanine hydroxylase gene (PAH) in a cohort of patients from 135 Slovak PKU families. Mutational screening of the known coding region, including conventional intron splice sites, was performed using high-resolution melting analysis, with subsequent sequencing analysis of the samples showing deviated melting profiles compared to control samples. The PAH gene was also screened for deletions and duplications using MLPA analysis. Forty-eight different disease causing mutations were identified in our patient group, including 30 missense, 8 splicing, 7 nonsense, 2 large deletions and 1 small deletion with frameshift; giving a detection rate of 97.6%. The most prevalent mutation was the p.R408W, occurring in 47% of all alleles, which concurs with results from neighboring and other Slavic countries. Other frequent mutations were: p.R158Q (5.3%), IVS12+1G>A (5.3%), p.R252W (5.1%), p.R261Q (3.9%) and p.A403V (3.6%). We also identified three novel missense mutations: p.F233I, p.R270I, p.F331S and one novel variant: c.-30A>T in the proximal part of the PAH gene promoter. A spectrum of 84 different genotypes was observed and a genotype based predictions of BH4-responsiveness were assessed. Among all genotypes, 36 were predicted to be BH4-responsive represented by 51 PKU families. In addition, genotype-phenotype correlations were performed.

Novel and recurrent mutations in the TAT gene in Tunisian families affected with Richner-Hanhart syndrome

Tyrosinemia type II, also designated as oculocutaneous tyrosinemia or Richner-Hanhart syndrome (RHS), is a very rare autosomal recessive disorder. In the present study, we report clinical features and molecular genetic investigation of the tyrosine aminotransferase (TAT) gene in two young patients, both born to consanguineous unions between first-degree cousins. These two unrelated families originated from Northern and Southern Tunisia. The clinical diagnosis was based on the observation of several complications related to Richner-Hanhart syndrome: recurrent eye redness, tearing and burning pain, photophobia, bilateral pseudodendritic keratitis, an erythematous and painful focal palmo-plantar hyperkeratosis and a mild delay of mental development. The diagnosis was confirmed by biochemical analysis. Sequencing of the TAT gene revealed the presence of a previously reported missense mutation (c.452G>A, p.Cys151Tyr) in a Tunisian family, and a novel G duplication (c.869dupG, p.Trp291Leufs 6). Early diagnosis of RHS and protein-restricted diet are crucial to reduce the risk and the severity of long-term complications of hypertyrosinemia such as intellectual disability.

Characterization of the human mitochondrial thiamine pyrophosphate transporter SLC25A19 minimal promoter: a role for NF-Y in regulating basal transcription

Transcriptional regulation of expression of the human mitochondrial thiamine pyrophosphate transporter (the product of the SLC25A19 gene) is unknown. To understand this regulation, we cloned and characterized the 5'-regulatory region of the SLC25A19 gene (1,080 bp). The cloned fragment was found to possess promoter activity in transiently transfected human-derived liver HepG2 cells. 5'- and 3'-deletion analysis has identified the minimal region required for basal SLC25A19 promoter activity to be between -131 and +20 (using the distal transcriptional start site as +1). The minimal promoter lacks typical TATA motif and contains two inverted CCAAT boxes (binding sites for NF-Y transcriptional factor). By means of mutational analysis, the critical role of both the upstream and downstream CCAAT boxes in basal SLC25A19 promoter activity was established; however, each of these boxes alone was found to be unable to support promoter activity. EMSA and supershift EMSA (with the use of specific antibodies against NF-Y subunits) studies, as well as chromatin immunoprecipitation assay, demonstrated the binding of NF-Y to both CCAAT boxes in vitro and in vivo, respectively. The requirement for NF-Y in SLC25A19 promoter activity in vivo was directly confirmed by the use of a dominant negative NF-YA mutant in transiently transfected HepG2 cells. These studies report for the first time the characterization of the SLC25A19 promoter and demonstrate an essential role for NF-Y in its basal activity.

FB-NOF is a non-autonomous transposable element, expressed in Drosophila melanogaster and present only in the melanogaster group

Most foldback elements are defective due to the lack of coding sequences but some are associated with coding sequences and may represent the entire element. This is the case of the NOF sequences found in the FB of Drosophila melanogaster, formerly considered as an autonomous TE and currently proposed as part of the so-called FB-NOF element, the transposon that would be complete and fully functional. NOF is always associated with FB and never seen apart from the FB inverted repeats (IR). This is the reason why the FB-NOF composite element can be considered the complete element. At least one of its ORFs encodes a protein that has always been considered its transposase, but no detailed studies have been carried out to verify this. In this work we test the hypothesis that FB-NOF is an active transposon nowadays. We search for its expression product, obtaining its cDNA, and propose the ORF and the sequence of its potential protein. We found that the NOF protein is not a transposase as it lacks any of the motifs of known transposases and also shows structural homology with hydrolases, therefore FB-NOF cannot belong to the superfamily MuDR/foldback, as up to now it has been classified, and can be considered as a non-autonomous transposable element. The alignment with the published genomes of 12 Drosophila species shows that NOF presence is restricted only to the 6 Drosophila species belonging to the melanogaster group.