A genetic algorithm-based method for the mechanical characterization of biosamples using a MEMS microgripper: numerical simulations.

In this paper, the viscoelastic characterization of biosamples is addressed considering a measuring technique relying on the use of a MEMS techonology-based microgripper. A proper mechanical model is developed for the coupled nonlinear dynamics of the microsystem, composed of the measuring tool and the specimen to be analyzed. The Maxwell liquid drop model and the generalized Maxwell-Wiechert model are considered for the sample, and the identification of the viscoelastic parameters is performed by implementing a genetic algorithm.

The use of nuclear and mitochondrial single nucleotide polymorphisms to identify cryptic species.

There is growing interest in the use of single nucleotide polymorphisms for evolutionary and population genetics. We tested the efficacy of one of the available single nucleotide polymorphism techniques, single-base extension, in distinguishing four cryptic species of Microtus. Sequence data were available for these species at nuclear and mitochondrial loci and their identity could be independently confirmed using karyotypes. We found that the development and optimization of single nucleotide polymorphisms required extensive effort, and that the method accurately identified the correct nucleotide at single nucleotide polymorphism sites approximately 90% of the time at the conserved nuclear locus. Correct identification rates were much lower at the highly variable mitochondrial locus.

Effects of contaminants on genetic patterns in aquatic organisms: a review.

There is increasing awareness of the need to evaluate the effects of contaminants at the population level. Genetic techniques offer a powerful approach to assess contaminant-induced changes in populations. Yet studies to date are relatively few and not always carefully designed to maximize the utility inherent in this approach. We present a summary of contemporary genetic assessment methods and a review of published studies of genetic effects in field-exposed aquatic organisms. We discuss evaluations of genetic patterns that use genetic adaptation, allozyme variation, and molecular genetic (DNA) variation. Direct tests of genetic adaptation are very effective in establishing a concrete, and potentially deleterious population-level effect of contaminant exposure, but they are difficult to accomplish with most field-exposed organisms. Allozyme surveys are relatively simple and common, and may provide data that are suggestive of contaminant effects. However, these are rarely conclusive, primarily because few allozyme loci are variable and these few loci represent extremely small portions of the genome. Molecular genetic techniques have the potential to be very effective. But, there is a tendency to emphasize the power of the techniques, rather than the underlying causes of the molecular genetic patterns observed. The strength of the conclusions of each study varies widely, partially derived from variation in the strength of the techniques. We caution that all these approaches are greatly improved by careful experimental design that includes adequate numbers of reference and contaminated sites and sample size. In addition, careful exposure assessment is required, including site and tissue chemistry, biomarker responses, and measures of potentially deleterious effects, such as DNA damage, or reduced reproductive output or survival.

Undifferentiated connective tissue disease with antibodies to Ro/SSa: clinical features and follow-up of 148 patients.

OBJECTIVE: To evaluate the clinical and serologic profile, the rate of progression to well defined CTD and the possible predictors of disease evolution in patients affected by UCTD with antibodies anti-RoISSA. METHODS: 148 patients diagnosed as UCTD were retrospectively evaluated. Antibodies to SSA/Ro were determined by counter-immunoelectrophoresis and ELISA. RESULTS: Thirty-six patients (24.3%) developed a well-defined CTD after a mean follow-up of 4.5 years. Most patients developed primary Sjögren's syndrome (SS) (50%) or systemic lupus erythematosus (SLE) (30.5%). Leukopenia and xerophthalmia developed more frequently in the group of patients evolving to defined CTDs (p < 0.0032 and p < 0.0063). Leukopenia independently predicted the evolution in CTD by multivariate regression analysis (p < 0.019). Anti-dsDNA predicted the evolution in SLE (p < 0.0207), while the presence of additional anti-ENA specificity to anti-Ro/SSA was not associated with the outcome. CONCLUSION: 24.3% of patients with UCTD and antibodies to Ro/SSA can progress in a relatively short period of time to well-defined CTDs. The development of primary SS could be predicted by xerophthalmia and SLE by the appearance of anti-dsDNA antibodies.

Genome duplication events and functional reduction of ploidy levels in sturgeon (Acipenser, Huso and Scaphirhynchus).

Sturgeon (order Acipenserformes) provide an ideal taxonomic context for examination of genome duplication events. Multiple levels of ploidy exist among these fish. In a novel microsatellite approach, data from 962 fish from 20 sturgeon species were used for analysis of ploidy in sturgeon. Allele numbers in a sample of individuals were assessed at six microsatellite loci. Species with approximately 120 chromosomes are classified as functional diploid species, species with approximately 250 chromosomes as functional tetraploid species, and with approximately 500 chromosomes as functional octaploids. A molecular phylogeny of the sturgeon was determined on the basis of sequences of the entire mitochondrial cytochrome b gene. By mapping the estimated levels of ploidy on this proposed phylogeny we demonstrate that (I) polyploidization events independently occurred in the acipenseriform radiation; (II) the process of functional genome reduction is nearly finished in species with approximately 120 chromosomes and more active in species with approximately 250 chromosomes and approximately 500 chromosomes; and (III) species with approximately 250 and approximately 500 chromosomes arose more recently than those with approximately 120 chromosomes. These results suggest that gene silencing, chromosomal rearrangements, and transposition events played an important role in the acipenseriform genome formation. Furthermore, this phylogeny is broadly consistent with previous hypotheses but reveals a highly supported oceanic (Atlantic-Pacific) subdivision within the Acipenser/Huso complex.

Anti-Ro(SS-A) 52 kDa and 60 kDa specificities in undifferentiated connective tissue disease.

UNLABELLED: Autoantibodies to Ro(SS-A) may recognize two different polypeptides, of 52 kDa and 60 kDa, respectively. We used an ELISA with purified human recombinant antigens to conduct a detailed analysis of the specificities of anti-Ro(SS-A) antibodies from 170 patients with definite diagnoses (systemic lupus erythematosus [SLE], n = 55; primary Sjögren's syndrome [PSS], n = 39; systemic sclerosis, n = 9; rheumatoid arthritis [RA], n = 10) or undifferentiated connective tissue disease (UCTD, n = 57). Most of the patients with SLE or PSS had both anti-52 kDa and -60 antibodies; isolated anti-60 kDa antibodies were found in 13% of the SLE patients and in none of the PSS patients, whereas high titers of anti-52 kDa were more common in the PSS than in the SLE patients. In the UCTD patients, the anti-Ro(SS-A) profile showed no significant correlations with clinical features but was associated with the clinical outcome. Over the mean follow-up of five years, definite SLE developed in four of the five UCTD patients with isolated anti-60 kDa vs only one of the remaining 52 patients (P < 0.0001); progression to PSS was seen in seven of the 34 patients with both anti-52 kDa and anti-60 kDa vs none of the remaining 23 patients (P = 0.03); none of the 12 patients with isolated anti-52 kDa developed a definite connective tissue disease. CONCLUSION: Our study suggests that analysis of anti-Ro(SS-A) specificity may provide useful information for predicting the course of UCTD.

Anterior chest wall arthritis and osteitis associated with Sneddon-Wilkinson disease.

We describe a 46-year-old man in whom anterior chest wall arthritis and clavicular osteomyelitis occurred together with sub-corneal pustular dermatosis (Sneddon-Wilkinson disease). This observation extends the list of neutrophilic skin lesions that may be involved in the so-called SAPHO syndrome.