Visceral and subcutaneous adiposity measurements in adults: influence of measurement site

Objective: Excess abdominal adiposity is a known risk factor for cardiovascular diseases. Computed tomography can be used to examine the visceral (VAT) and subcutaneous (SAT) components of abdominal adiposity, but it is unresolved whether single‐slice or multi‐slice protocols are needed. Research Method and Procedures: Nine computed tomography scans were obtained in the lumbar spine region of 24 adults. The nine slices were obtained at three intervertebral positions (L2–L3, L3–L4, and L4–L5) and at 7 mm above and below these locations. Intra‐site and inter‐site differences in SAT, VAT, total adipose tissue, and the VAT/SAT ratio were examined using ANOVA and confidence intervals for pairwise differences between means. Results: Intervertebral SAT values increased from 103.1 ± 50.9 (standard deviation) cm² at L2–L3 to 153.3 ± 68.8 cm² at L4–L5, whereas the corresponding VAT values decreased from 164.3 ± 125.4 to 126.0 ± 82.7 cm². The VAT/SAT ratio was not constant, decreasing from 1.8 ± 1.4 to 0.9 ± 0.7. Repeated‐measures ANOVA indicated significant inter‐ and intra‐site differences (p ≤ 0.02) for SAT, VAT, and the VAT/SAT ratio at L3?L4 and L4?L5 (p < 0.001). Discussion: These differences show the limitation of using a single‐slice assessment of abdominal fat distribution, both for a subject and between subjects. Furthermore, the sizeable differences in the intra‐site scans indicate that precise repositioning is needed for longitudinal studies. In summary, our findings suggest that a multi‐site imaging protocol may provide a more complete assessment of abdominal fat stores and distribution than use of a single site.     

Mitochondrial damage modulates alternative splicing in neuronal cells: implications for neurodegeneration

Mitochondrial damage is linked to many neurodegenerative conditions, such as Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis. These diseases are associated with changes in the splicing pattern of individual mRNAs. Here, we tested the hypothesis that mitochondrial damage modulates alternative splicing, not only of a few mRNAs, but in a general manner. We incubated cultured human neuroblastoma cells with the chemical agent paraquat (a neurotoxin that interferes with mitochondrial function, causing energy deficit and oxidative stress) and analysed the splicing pattern of 13 genes by RT-PCR. For all mRNAs that are alternatively spliced, we observed a dose- and time-dependent increase of the smaller isoforms. In contrast, splicing of all constitutive splicing exons that we monitored did not change. Using other drugs, we show that the modulation of alternative splicing correlates with ATP depletion, not with oxidative stress. Such drastic changes in alternative splicing are not observed in cell lines of non-neuronal origin, suggesting a selective susceptibility of neuronal cells to modulation of splicing. As a significant percentage of all mammalian mRNAs undergo alternative splicing, we predict that mitochondrial failure will unbalance a vast number of isoform equilibriums, which would give an important contribution to neurodegeneration.     

Genotyping of human alcohol dehydrogenases at the ADH2 and ADH3 loci following DNA sequence amplification

Humans are polymorphic at two of the alcohol dehydrogenase (ADH) loci important in ethanol metabolism, ADH2 and ADH3. Although the coding regions of these genes are 94% identical, they produce subunits that differ greatly in kinetic properties in vitro. These differences are likely to be reflected in the pharmacokinetics of alcohol metabolism, but studies have been hampered by the need to use liver biopsy specimens to determine the ADH phenotype. This problem has now been overcome by determining the genotype at these loci using DNA that has been amplified in vitro by the polymerase chain reaction. We report here the identification of all three of the ADH2 alleles and both of the ADH3 alleles. Any pair of ADH2 or ADH3 alleles can be distinguished using allele-specific oligonucleotide probes directed at their single base pair difference. In addition, ADH2(2) can be distinguished from ADH2(1) and ADH2(3) by detecting a new MaeIII site created in the third exon by the single base pair alteration in ADH2(2).     

Quantitative study of intimal longitudinal smooth muscle in human small mesenteric arteries

The present paper examines the results of quantitative assessment of intimal longitudinal smooth muscle (ILSM) in small arteries from normal mesentery in man. 212 vessels from 24 patients who underwent colectomy for colorectal carcinoma were studied. The mean amount of ILSM in these vessels was found to be 1.42% (range 0.00-8.90%) of external vessel diameter. A statistically significant (p = 0.018) positive correlation was demonstrated between the mean amount of ILSM in vessels from any individual patient and the level of diastolic blood pressure. It is concluded that increased intravascular tension is one factor which influences the development of ILSM in human small mesenteric arteries.     

ADAPTIVE RADIATION AND GENETIC DIFFERENTIATION IN THE HAWAIIAN SILVERSWORD ALLIANCE (COMPOSITAE: MADIINAE)

The Hawaiian silversword alliance consists of the three genera Dubautia, Argyroxiphium, and Wilkesia, and is a classic example of adaptive radiation in an insular setting. Genetic variation and interspecific genetic differentiation based on ten enzyme loci are described for Dubautia and Wilkesia. Genetic identities among species span the range of values expected from interpopulation comparisons within a single species (I = 0.90–1.00) to those typical of interspecific comparisons . Genetic-identity values correspond to biogeographic distribution and morphological distinctiveness, supporting a correlation of increasing genetic distance associated with the time of separation among lineages. It may be inferred that the high genetic identities observed within the Hawaiian Madiinae and other island plant groups are due to limited time spans available for taxa to accumulate new genetic variation through mutation. It appears that species may remain genetically similar (I > 0.90) even after time spans on the order of magnitude of 1,000,000 years.     

Molecular cloning and sequence analysis of mutant alleles of the fission yeast cdc2 protein kinase gene: Implications for cdc2+ protein structure and function

Summary The cdc2 ⁺ gene function plays a central role in the control of the mitotic cell cycle of the fission yeast Schizosaccharomyces pombe. Recessive temperature-sensitive mutations in the cdc2 gene cause cell cycle arrest when shifted to the restrictive temperature, while a second class of mutations within the cdc2 gene causes a premature advancement into mitosis. Previously the cdc2 ⁺ gene has been cloned and has been shown to encode a 34 kDa phosphoprotein with in vitro protein kinase activity. Here we describe the cloning of 11 mutant alleles of the cdc2 gene using two simple methods, one of which is presented here for the first time. We have sequenced these alleles and find a variety of single amino acid substitutions mapping throughtout the cdc2 protein. Analysis of these mutations has identified a number of regions within the cdc2 protein that are important for cdc2 ⁺ activity and regulation. These include regions which may be involved in the interaction of the cdc2 ⁺ gene product with the proteins encoded by the wee1 ⁺, cdc13 ⁺ and suc1 ⁺ genes.     

Avian thymic hormone (ATH) is a parvalbumin

Amino acid sequence analysis of a protein from chicken thymus tissue which promotes immunological maturity in chicken bone marrow cells in culture has established sequences of a 45-residue fragment, a 24-residue fragment and a 9-residue and an 8-residue peptide. Independent comparison of the 45- and 24-residue fragments with known amino acid sequences by computer search has unequivocally identified avian thymic hormone as a parvalbumin. This is the first demonstration that a protein previously identified by a biological function is a parvalbumin.     

Novel cnidocysts of narcomedusae and a medusivorous ctenophore, and confirmation of kleptocnidism

Cnidocysts have been examined from the tentacles of the ctenophore Haeckelia rubra (Euchlora rubra) and five species of hydrozoan narcomedusae (Solmundella bitentaculata, Aegina citrea, Solmissus marshalli, Solmissus albescens, and Cunina sp.) using TEM, both in sections and by firing whole cnidocysts onto EM grids. The study revealed that these apotrichous isorhiza cnidocysts have a novel morphology in which the intracapsular inverted tubule has five circumferential pleats when viewed in transverse section, rather than the usual three pleats. Accordingly, the definition of helicoptychoneme cnidocysts has been broadened to include both the usual three-pleated cnidocysts and these new five-pleated cnidocysts. In general, apotrichous isorhizas have subspherical capsules with a thick, bilayered wall, whose interior is nearly filled with the regularly coiled, helically folded, five-pleated inverted tubule. Upon discharge, the everted tubule is several mm long and the five circumferential pleats become manifested as five helical rows of spines running up the tubule, which has three morphologically different segments. The very short basal segment is devoid of ornamentation; the remaining proximal portion is characterized by five spirals of uniform, closely packed short spines; the long distal portion is characterized by a single spiral of regularly spaced large spines that derive from all five spirals-the five spirals are otherwise demarcated in the distal portion by 'scales' that are visible only with the electron microscope.     

Ethno-behaviorism and the culture-bound syndromes: The case of amok

The phenomenon of amok is reviewed in order to demonstrate the heuristic value of an ethno-behavioral model of culture-bound syndromes. The notion that culture-bound syndromes share underlying common disease forms is rejected. Instead, the ethno-behavioral model postulates that culture-bound syndromes consist of culturally specific behavioral repertoires legitimated by culturally sanctioned norms and concepts, but with both behavior and norms acquired in accordance with basic principles of human learning universal to all cultures. Consistent with this model, amok is shown to be a common behavioral pathway for multiple precipitants (which may or may not include disease pathology), but with a distinct form and conceptualization which can be traced to the social learning practices and beliefs of the Malay.[/p]