Optimal form of operationalizing BMI in relation to all-cause and cause-specific mortality: the original Whitehall study

Objective: The shape of the association between BMI (kg/m²) and mortality has important methodological implications as it partially determines the optimal form for operationalizing BMI for use in analyses. We examined various BMI operationalizations in relation to mortality from all causes and specific causes. Methods and Procedures: A clinical examination with measurements of height and weight was conducted at baseline (1967–1970) for 18,860 working men aged 40–69, in the total cohort and 7,865 men in the healthy subcohort, that is, those who had no unexplained weight loss, no cardiovascular (CVD) or respiratory disease, were nonsmokers and did not die during the first 5 years of follow‐up (the original Whitehall study). A mean follow‐up of 35 years for mortality gave rise to 13,498 deaths of which 4,766 were in the healthy subcohort. Results: There was a dose‐response relation between BMI and CVD and coronary heart disease (CHD) mortality in the total cohort and healthy subcohort, with an increasingly steep slope at the high end of the BMI distribution. For noncardiovascular, cancer, and respiratory mortality, an excess risk was also associated with a BMI <18.5; in the healthy subcohort, this was true only for respiratory deaths. The association between BMI and all‐cause mortality was J‐shaped in the total cohort and healthy subgroup and even after excluding underweight participants. Discussion: For associations with all‐cause and cause‐specific mortality, a linear and quadratic term in combination provided a more parsimonious BMI operationalization than the WHO definition, obese‐nonobese dichotomy or BMI treated as a continuous linear variable.     

Seed morphology,presence of areoles and water entry at imbibition of <i>Vicia dasycarpa</i> Ten. cv. Tolse F.C.A

The morphological characteristics of the seeds of Vicia dasycarpa Ten. cv. Tolse FCA were studied in relation to the area of imbibition water entry and were considered the presence of areoles. Seeds were analyzed using a stereo, optical and scanning electron microscope (SEM). The determination of the initial water entry area was carried out by immersing the seeds in a solution of tetrazolium (1%). This study showed that this species has seeds with a halo framing the hilum, an inconspicuous dry aril and a deltoid micropyle. The seedcoat pattern is papillose. The tracheid bar is surrounded by a ring of parenchymatous cells, and the tracheids show slight warty and non-vestured pits. It was confirmed the presence of an endospermic radicle pocket that surrounds and protect the radical tip. Two pairs of cotyledonar areoles were identified. It was established that the entry of water during imbibition starts in the area of the lens -having cracks- and moves in the sagittal plane. Both citological characteristic of tracheid bar and areoles presence show an apomorfous state between the Papiplionoids.     

A simple method for studying whole sections of rice grain

We developed a new and simple method to collect sections of a whole brown rice kernel for investigation of histological properties. A single kernel of rice was dehydrated through a graded ethanol series, transferred to xylene, and embedded in paraffin. During sectioning of the blocks using a rotary microtome, we used a special adhesive tape to collect and place the sections on slides so they remained flat. The use of the adhesive tape technique combined with autofluorescence characteristics allowed us to visualize cell walls throughout an entire longitudinal or transverse section of a whole rice kernel. We obtained scanning electron microscopy images of the sections to determine section quality.     

Staphylococcus aureus and Wegener's granulomatosis

Wegener's granulomatosis (WG) is a form of systemic vasculitis. It is characterized by granulomatous inflammation in the upper and lower airways, vasculitis and necrotizing glomerulonephritis, and is strongly associated with antineutrophil cytoplasmic antibodies against proteinase 3. Since the etiology of the disease is not clear, treatment, consisting of corticosteroids and immunosuppressives, is nonspecific and associated with severe side effects. Pinpointing the trigger(s) of the disease would highly improve treatment. Clinical evidence shows that an infectious agent, the bacterium Staphylococcus aureus, is a risk factor for disease relapse, suggesting its involvement in the pathogenesis of WG. Here we review both clinical and experimental data that either indicate or support a role for S. aureus in WG.     

Autoantibodies directed to novel components of the PM/Scl complex, the human exosome

The autoantigenic polymyositis/scleroderma (PM/Scl) complex was recently shown to be the human homologue of the yeast exosome, which is an RNA-processing complex. Our aim was to assess whether, in addition to targeting the known autoantigens PM/Scl-100 and PM/Scl-75, autoantibodies also target recently identified components of the PM/Scl complex. The prevalence of autoantibodies directed to six novel human exosome components (hRrp4p, hRrp40p, hRrp41p, hRrp42p, hRrp46p, hCsl4p) was determined in sera from patients with idiopathic inflammatory myopathy (n = 48), scleroderma (n = 11), or the PM/Scl overlap syndrome (n = 10). The sera were analyzed by enzyme-linked immunosorbent assays and western blotting using the affinity-purified recombinant proteins. Our results show that each human exosome component is recognized by autoantibodies. The hRrp4p and hRrp42p components were most frequently targeted. The presence of autoantibodies directed to the novel components of the human exosome was correlated with the presence of the anti-PM/Scl-100 autoantibody in the sera of patients with idiopathic inflammatory myopathy (IIM), as was previously found for the anti-PM/Scl-75 autoantibody. Other clear associations between autoantibody activities were not found. These results further support the conception that the autoimmune response may initially be directed to PM/Scl-100, whereas intermolecular epitope spreading may have caused the autoantibody response directed to the associated components.     

The elimination of primer-dimer accumulation in PCR.

We attempted to produce primer-dimers (PDs) from a variety of primers with differing types and extents of complementarity. Where PDs were produced they were cloned and sequenced. We were unable to produce detectable PDs either with individual primers alone or with similar sequence primers even if they had 3'complementarity. These observations led to the hypothesis that a system could be developed whereby the accumulation of PDs in a PCR may be eliminated. We demonstrate a method for the general suppression of PD formation that uses a sequence of additional nucleotides (a Tail) at the 5' ends of amplimers. Tailed amplimers are present at low concentration and only participate during early cycles of PCR. In subsequent PCR cycles, amplification is achieved using a single primer that has the same sequence as that of the Tail portion of the early cycle primers, here we refer to this as a Tag. When products are small, as with PDs, there is a high local concentration of complementary sequences derived from the Tail. This favours the annealing of the complementary ends of a single strand produced by tailed primer interactions and gives rise to 'pan-handle' structures. The formation of these outcompetes the annealing of further Tag primers thereby preventing the accumulation of non-specific PD products. This aids the design of large multiplex reactions and provides a means of detecting specific amplicons directly in the reaction vessel by using an intercalating dye.     

Probing cytoskeleton modulation by optical biosensors

This paper reported the use of resonant waveguide grating biosensors for studying the cytoskeleton structure in cells. This was achieved by measuring the changes in mass within the bottom portion of cells upon exposure to saponin in the absence and presence of cytoskeleton modulators. Treatment of Chinese hamster ovary cells with saponin led to a dose-dependent and dynamic mass changes. When a higher concentration of saponin (> 60 microg/ml) was used, a net loss in mass was observed. This is probably resulted from the diffusion of soluble intracellular materials away from the bottom portion of cells after pore formation in the cell plasma membranes by saponin. The pretreatment of cells with actin disruption agents, cytochalasin B and latrunculin A, led to significantly increased loss in cell mass induced by either 75 or 125 microg/ml saponin. These results suggested that optical biosensors provide an attractive means to study the cytoskeleton structure and screen modulators that affect the cytoskeleton structure.     

Polymorphism and divergence at the prune locus in Drosophila melanogaster and D. simulans

The prune locus of Drosophila melanogaster lies at the tip of the X chromosome, in a region of reduced recombination in which nearby loci show reduced variation relative to evolutionary divergence from D. simulans. DNA sequencing of prune alleles from D. melanogaster and D. simulans reveals extremely low variation in D. melanogaster but greater variation in D. simulans. Divergence between the two species is not reduced. This pattern may be explained by either positive selection leading to hitchhiking of neutral variation or background selection against deleterious mutations. The pattern of silent versus replacement polymorphism and divergence at prune is consistent with either a model of weakly deleterious selection against amino acid substitutions or balancing selection.