Obesity-dependent metabolic signatures associated with nonalcoholic fatty liver disease progression

Our understanding of the mechanisms by which nonalcoholic fatty liver disease (NAFLD) progresses from simple steatosis to steatohepatitis (NASH) is still very limited. Despite the growing number of studies linking the disease with altered serum metabolite levels, an obstacle to the development of metabolome-based NAFLD predictors has been the lack of large cohort data from biopsy-proven patients matched for key metabolic features such as obesity. We studied 467 biopsied individuals with normal liver histology (n=90) or diagnosed with NAFLD (steatosis, n=246; NASH, n=131), randomly divided into estimation (80% of all patients) and validation (20% of all patients) groups. Qualitative determinations of 540 serum metabolite variables were performed using ultraperformance liquid chromatography coupled to mass spectrometry (UPLC-MS). The metabolic profile was dependent on patient body-mass index (BMI), suggesting that the NAFLD pathogenesis mechanism may be quite different depending on an individual's level of obesity. A BMI-stratified multivariate model based on the NAFLD serum metabolic profile was used to separate patients with and without NASH. The area under the receiver operating characteristic curve was 0.87 in the estimation and 0.85 in the validation group. The cutoff (0.54) corresponding to maximum average diagnostic accuracy (0.82) predicted NASH with a sensitivity of 0.71 and a specificity of 0.92 (negative/positive predictive values=0.82/0.84). The present data, indicating that a BMI-dependent serum metabolic profile may be able to reliably distinguish NASH from steatosis patients, have significant implications for the development of NASH biomarkers and potential novel targets for therapeutic intervention.

Self-focusing arrest of femtosecond laser pulses in air at different pressures

We study analytically and numerically the self-focusing arrest of femtosecond laser pulses in air at different pressures in the presence of an external focus lens. Analytical estimations as well as results of simulations show that the intensity at which the self-focusing arrest occurs is almost independent of the gas pressure. However, a dependence on the temperature is found. The Raman effect is taken into account, and an estimation of the intensity inside of filaments at high altitudes is given.

Experiment and simulations on the energy reservoir effect in femtosecond light filaments

We report the results of an experiment and numerical simulations that demonstrate the large spatial extent and the effect of the so-called energy reservoir during the filamentation of femtosecond laser pulses in air. By inserting pinholes of different sizes in the filament path we observe different stages of development ranging from the termination of the filament, through its partial survival, to undisturbed propagation. A background containing up to 50% of the pulse energy is found to be necessary to maintain the filament formation, including a first refocusing.

Variational analysis of self-focusing of intense ultrashort pulses in gases

By using perturbation theory we derive an expression for the electrical field of a Gaussian laser beam propagating in a gas medium. This expression is used as a trial solution in a variational method to get quasi-analytical solutions for the width, intensity, and self-focusing distance. The approximation gives a better agreement with results of numerical simulations for a broad range of values of the input power than previous analytical results available in the literature. The results apply in the case of ultrashort pulses too.

Worker interests and male production in Polistes gallicus, a Mediterranean social wasp

The resolution of social conflict in colonies may accord with the interests of the most numerous party. In social insect colonies with single once-mated queens, workers are more closely related to the workers' sons than they are to the queens' sons. Therefore, they should prefer workers to produce males, against the queen's interests. Workers are capable of producing males as they arise from unfertilized eggs. We found Polistes gallicus to have colonies of single, once-mated queens, as determined by microsatellite genotyping of the workers, so worker interests predict worker male production. In colonies lacking queens, workers produced the males, but not in colonies with original queens. Thus worker interests were expressed only when the queen was gone. The high fraction of missing queens and early end to the colony cycle relative to climate so early in the season is surprising and may indicate a forceful elimination of the queen.

[Prognostic significance and clinic utility of serum and immunohistochemical cathepsin B levels in colorectal cancer]

BACKGROUND

Aproximately one third of node-negative colorectal cancer recur suggesting the presence of micrometastasis not detected by conventional histopathologic methods. We think that the role of enzymes like Cathepsin B play in the process of invasion and metastasis in colorectal cancer might identify at earlier stages patients with high risk of shorter survival and who need more aggressive treatment. Our porpuse is to evaluate the prognostic significance of preoperative serum and inmunohistochemical levels of cathepsin B to identify colorectal carcinomas with worse prognostic.

METHODS

Fifty five patients undergoing surgical treatment for colorectal cancer from 1998 to 2000. As a control group sera from 23 patients with acute appendicitis. Serum levels of cathepsin B were obtained preoperatively (KRKA, Novo Slovenia;ng/ml); cathepsin B inmunoreactivity was determinated after surgical treatment, (C-19, Santa Cruz Biotechnology). Serum levels of CEA (Inmulit 2000 CEA), and CA 19,9 (Inmulite Gi-Ma, Diagnostic Products Corporation, Los Angeles, CA), and p53 expression (Dako) were determinated in patients with colorectal cancer. Survival analysis was realized using Cox and Kaplan-Meier methods (SPSS 10.0 for Windows).

RESULTS

The mean age of patients with colorectal cancer was 68 years (range 39-87 years). 29 males and 26 females. Tumor size was 4.6 cms., range 1-12. Rectal localization, 32.2%. Moderately differentiated, 49.1%. The median serum and inmunohistochemical levels of cathepsin B were 5.74 ng/ml and 29.56% in patients with acute appendicitis respectively. Preoperative serum levels in patients with colorectal cancer were: CEA, 46.04 ng/ml (range 0.21-7.32 ); CA 19,9, 110.52 UI/ml, (range 2.5-1920); and Cathepsin B, 6.94 ng/ml, range 3.57-11.6). Inmunohistochemical results were: p53, 44.36%, (range 0-95); Cathepsin B, 66.9% (range 10-90). Serum and inmunhistochemical values were significantly increased in patients with colorectal cancer when compared with control group, p=0,011 and p=0,000. High serum levels of cathepsib B were significantly associated wiyh shorter survival of patients with colorectal cancer in univariate and multivariate methods, p=0.041;HR 1.281 95%CI (1.043-1.716) and p= 0.022; HR 1.338.955 CI (1.043-1.716).

CONCLUSIONS

Cathepsin B can be used like an independent prognostic tumoral marker in colorectal cancer. Preoperative serum levels over 6.94 ng/ml, are associated with worse prognostic and shorter survival.

Ancient conservation of trinucleotide microsatellite loci in polistine wasps

Microsatellites have proven to be very useful genetic markers for studies of kinship, parentage, and gene mapping. If microsatellites are conserved among species, then those developed for one species can be used on related species, which would save the time and effort of developing new loci. We evaluated conservation of 27 trinucleotide loci that were derived from 2 species of Polistes wasps in cross-species applications on 27 species chosen from the major lineages of the Vespidae, which diverged as much as 144 million years ago. We further investigated cross-species polymorphism levels for 18 of the loci. There was a clear relationship between cladistic distance and both conservation of the priming sites and heterozygosity. However the loci derived from P. bellicosus were much more widely conserved and polymorphic than were those derived from P. annularis. The disparity in cross-species utility between these sets of loci means that caution should be used in generalizing from conservation rates derived from single species. We found no relationship between locus conservation or heterozygosity and GC content of flanks, repeat motif, repeat length, or heterozygosity in the original species, which suggests that generalizations from other studies reporting such patterns are premature.

First Report of Banana Streak Virus Infecting Sugarcane and Arrowroot in Colombia

We have recently reported on the presence of banana streak virus (BSV) affecting plantains (Musa spp.) in Colombia (2). BSV is serologically related to sugarcane bacilliform virus and has been found to be transmitted by the pink mealybug (Saccharicoccus sacchari) from sugarcane to banana (1). In the vicinity of affected plantain crops in the localities of Andes (Antioquia) and Montenegro (Quindio), we observed sugarcane (Saccharum officinarum L.) plants with chlorotic streaks on their leaves, as well as arrowroot (Canna edulis Ker-Gawl.) plants with mild mosaic symptoms. The foliar tissue of symptomatic plants of these two species was tested for BSV and cucumber mosaic virus (CMV) by double antibody sandwich-enzyme-linked immunosorbent assay with commercial polyclonal antisera (Agdia Inc., Elkhart, IN). BSV was detected in samples of both plant species, whereas CMV was not detected in either one. Immunosorbent electron microscopy analysis of BSV-infected, symptomatic, foliar tissue of sugarcane showed the presence of viral-like bacilliform particles measuring approximately 150 × 30 nm, typical of BSV. This is the first report of BSV infecting Saccharum officinarum in Colombia and the first report of Canna edulis as a host for this virus. References: (1) B. E. L. Lockhart and L. J. C. Autrey. Plant Dis. 72:230, 1988. (2) H. Reichel et al. Plant Dis. 80:463, 1996.

Support for the hypothesis of anguimorph ancestry for the suborder Serpentes from phylogenetic analysis of mitochondrial DNA sequences

Snakes represent one of the most ubiquitous and successful groups of terrestrial vertebrates; however, many aspects of their evolutionary relationships remain uncertain. Previous research, which utilized morphological and immunological data, has not resolved the origin of snakes or clearly delineated the relationships between snakes and other lizards. A DNA sequence data set from the mitochondrial ND4 gene and the histidine, serine, and leucine tRNAs has been generated for use in the examination of these relationships. Parsimony analyses employing multiple outgroups resolve snakes within the lizard clade. Varanus is the sister group to the snakes in 81% of bootstrap replications using Bos as the outgroup specified, 85% using Trachemys, 57% using Alligator, and 80% using all three outgroups. The primitive, fossorial snake genera Leptotyphlops and Typhlops are basal to the other snakes and provide tentative molecular evidence in support of a fossorial or subfossorial origin of limblessness for the suborder Serpentes.