Are the intertidal fish highly resistant to UV-B radiation? A study based on oxidative stress in Girella laevifrons (Kyphosidae)

Sea chub, Girella laevifrons, is a coastal fish that inhabits high intertidal rockpools along the coast of Chile. The intertidal pools where the juveniles live, are an extreme environment with high levels of ultraviolet (UV) radiation, becoming harmful to the organisms, due to oxidative stress generated by reactive oxygen species. For this reason organisms develop adaptations that allow them to survive in this complex environment. The search of biomonitor species, sensitive to UV radiation is very important in aquatic ecosystems, mainly in the southern hemisphere where depletion of the ozone layer and the consequent increase of UV radiation, have become an environmental problem. The aim of this study was to evaluate the effect of ultraviolet radiation in G. laevifrons and its possible use as UV-B radiation biomonitor specie in intertidal systems, which are very important for the Chilean fisheries. The effect of UV radiation exposure on juvenile G. laevifrons was measured through oxidative stress parameters. Catalase's activity increased with the time of exposure, unlike superoxide dismutase's activity which peaked at 2h, decreasing towards the 5th hour of irradiation. The superoxide dismutase activity in muscle tissue did not show significant differences. The lipid peroxidation and DNA damage increased in relation to exposition times. Tissue muscle's DNA damage was shown only at 5h of exposure. Significant differences between the two organs in the antioxidant capacity were observed, the liver of G. laevifrons exhibited the higher antioxidant capacity. It can be concluded that this specie exhibits effective protection mechanisms against UV radiation exposure and it is not appropriate specie as a biomonitor in intertidal systems.

Response of high-risk of recurrence/progression bladder tumours expressing sialyl-Tn and sialyl-6-T to BCG immunotherapy

Background:

High risk of recurrence/progression bladder tumours is treated with Bacillus Calmette-Guérin (BCG) immunotherapy after complete resection of the tumour. Approximately 75% of these tumours express the uncommon carbohydrate antigen sialyl-Tn (Tn), a surrogate biomarker of tumour aggressiveness. Such changes in the glycosylation of cell-surface proteins influence tumour microenvironment and immune responses that may modulate treatment outcome and the course of disease. The aim of this work is to determine the efficiency of BCG immunotherapy against tumours expressing sTn and sTn-related antigen sialyl-6-T (s6T).

Methods:

In a retrospective design, 94 tumours from patients treated with BCG were screened for sTn and s6T expression. In vitro studies were conducted to determine the interaction of BCG with high-grade bladder cancer cell line overexpressing sTn.

Results:

From the 94 cases evaluated, 36 had recurrence after BCG treatment (38.3%). Treatment outcome was influenced by age over 65 years (HR=2.668; (1.344–5.254); P=0.005), maintenance schedule (HR=0.480; (0.246–0.936); P=0.031) and multifocallity (HR=2.065; (1.033–4.126); P=0.040). sTn or s6T expression was associated with BCG response (P=0.024; P<0.0001) and with increased recurrence-free survival (P=0.001). Multivariate analyses showed that sTn and/or s6T were independent predictive markers of recurrence after BCG immunotherapy (HR=0.296; (0.148–0.594); P=0.001). In vitro studies demonstrated higher adhesion and internalisation of the bacillus to cells expressing sTn, promoting cell death.

Conclusion:

s6T is described for the first time in bladder tumours. Our data strongly suggest that BCG immunotherapy is efficient against sTn- and s6T-positive tumours. Furthermore, sTn and s6T expression are independent predictive markers of BCG treatment response and may be useful in the identification of patients who could benefit more from this immunotherapy.

The role of prion protein in stem cell regulation

Cellular prion protein (PrP(C)) has been well described as an essential partner of prion diseases due to the existence of a pathological conformation (PrP(Sc)). Recently, it has also been demonstrated that PrP(C) is an important element of the pluripotency and self-renewal matrix, with an increasing amount of evidence pointing in this direction. Here, we review the data that demonstrate its role in the transcriptional regulation of pluripotency, in the differentiation of stem cells into different lineages (e.g. muscle and neurons), in embryonic development, and its involvement in reproductive cells. Also highlighted are recent results from our laboratory that describe an important regulation by PrP(C) of the major pluripotency gene Nanog. Together, these data support the appearance of new strategies to control stemness, which could represent an important advance in the field of regenerative medicine.

Genetic analysis of reaction time variability: room for improvement?

BACKGROUND

Increased reaction time variability (RTV) on cognitive tasks requiring a speeded response is characteristic of several psychiatric disorders. In attention deficit hyperactivity disorder (ADHD), the association with RTV is strong phenotypically and genetically, yet high RTV is not a stable impairment but shows ADHD-sensitive improvement under certain conditions, such as those with rewards. The state regulation theory proposed that the RTV difference score, which captures change from baseline to a rewarded or fast condition, specifically measures 'state regulation'. By contrast, the interpretation of RTV baseline (slow, unrewarded) scores is debated. We aimed to investigate directly the degree of phenotypic and etiological overlap between RTV baseline and RTV difference scores. Method We conducted genetic model fitting analyses on go/no-go and fast task RTV data, across task conditions manipulating rewards and event rate, from a population-based twin sample (n=1314) and an ADHD and control sibling-pair sample (n=1265).

RESULTS

Phenotypic and genetic/familial correlations were consistently high (0.72-0.98) between RTV baseline and difference scores, across tasks, manipulations and samples. By contrast, correlations were low between RTV in the manipulated condition and difference scores. A comparison across two different go/no-go task RTV difference scores (slow-fast/slow-incentive) showed high phenotypic and genetic/familial overlap (r = 0.75-0.83).

CONCLUSIONS

Our finding that RTV difference scores measure largely the same etiological process as RTV under baseline condition supports theories emphasizing the malleability of the observed high RTV. Given the statistical shortcomings of difference scores, we recommend the use of RTV baseline scores for most analyses, including genetic analyses.

Evaluation of PCR for cutaneous leishmaniasis diagnosis and species identification using filter paper samples in Panama, Central America

Cutaneous leishmaniasis (CL) is a major vectorborne disease in Panama. In this study, the diagnostic performance and usefulness of two DNA extraction procedures from skin scraping samples collected on FTA filter paper for subsequent PCR diagnosis of CL was evaluated. A positive CL laboratory diagnosis was based on a positive parasitological test (Giemsa-stained smears or in vitro culture) and/or positive PCR test performed from skin scrapings collected in TE buffer (PCR-TE). Of 100 patients with skin lesions suggestive of CL, 82 (82%) were confirmed as CL positive. The sensitivity was calculated for each of the PCR approaches from samples collected on filter paper. The highest sensitivity was achieved by PCR-FTA processed by Chelex 100 (PCR-Chelex) (0.94). PCR-FTA extracted using the FTA purification reagent presented a lower sensitivity (0.60). Good concordance between routine PCR-TE and PCR-Chelex was observed (percent agreement=0.88, κ index=0.65). In conclusion, use of FTA filter paper for skin scraping collection combined with PCR is a reliable and convenient method for CL diagnosis in Panama, with comparable performance to the routine PCR method and with improved sensitivity compared with those of conventional parasitological methods.

Pronociceptive effect of 5-HT(1A) receptor agonist on visceral pain involves spinal N-methyl-D-aspartate (NMDA) receptor

The functional role of serotonergic 5-HT(1A) receptors in the modulation of visceral pain is controversial. The objective of this study was to systematically examine the mechanism and site of action of a selective 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino)-tetralin (DPAT) on visceral pain. In the behavioral model of visceral pain, systemic injection (5-250 μg/kg) of DPAT produced a significant increase in the viscero-motor response (VMR) to colorectal distension (CRD) and this effect was blocked by the selective 5-HT(1A) receptor antagonist WAY-100135 (5 mg/kg, s.c.). Similarly, intrathecal (i.t.) injection (5 μmol) of DPAT into the lumbo-sacral (L6-S1) spinal cord produced a significant increase in VMR. The administration of N-methyl D-aspartate (NMDA) receptor antagonist AP5 (50 μg/kg) prior to DPAT injection completely blocked the pronociceptive effect of DPAT. Similarly, DPAT failed to increase VMR in rats chronically treated with NR1 subunit-targeted antisense oligonucleotide (ON), whereas the drug increased VMR in rats treated with mismatched-ON. Chronic i.t. injection of allylglycine (AG), a γ-amino decarboxylase (GAD) enzyme inhibitor, produced significant increase in VMRs, suggesting that the inhibition of GABA synthesis produces pronociception. In AG-treated rats, i.t. injection of DPAT failed to further increase in VMR, suggesting that the DPAT action is linked to GABA release. Similarly, WAY-100135 failed to attenuate VMR in AG-treated rats, suggesting that unlike DPAT, AG action is not via the activation of 5-HT(1A) receptors. In electrophysiology experiments, DPAT (50 μg/kg) significantly increased the responses of spinal neurons to CRD, but did not influence the mechanotransduction property of CRD-sensitive pelvic nerve afferent fibers. The effect of DPAT on spinal neurons remained unaffected when tested in spinal-transected (C1-C2) rats. These results indicate that the 5-HT(1A) receptor agonist DPAT produces pronociceptive effects, primarily via the activation of presynaptic 5-HT(1A) receptors in GABAergic neuron to restrict GABA release and thereby disinhibits the excitatory glutamatergic neurons in the spinal cord.

Component-resolved diagnosis of vespid venom-allergic individuals: phospholipases and antigen 5s are necessary to identify Vespula or Polistes sensitization

BACKGROUND

Cross-reactivity between hymenoptera species varies according to the different allergenic components of the venom. The true source of sensitization must therefore be established to ensure the efficacy of venom immunotherapy.

OBJECTIVE

In the Mediterranean region, Polistes dominulus and Vespula spp. are clinically relevant cohabitating wasps. A panel of major vespid venom allergens was used to investigate whether serum-specific IgE (sIgE) could be used to distinguish sensitization to either vespid.

METHODS

Fifty-nine individuals with allergic reactions to vespid stings and positive ImmunoCAP and/or intradermal tests to vespid venoms were studied. sIgE against recombinant and natural venom components from each wasp species was determined using the ADVIA Centaur(®) system.

RESULTS

sIgE against recombinant antigen 5s sensitization to be detected in 52% of the patients tested (13/25). The sensitivity increased to 80% (20/25), when using natural antigen 5s, and to 100% with the complete panel of purified natural components, because the sIgE was positive to either the antigen 5s (Pol d 5/Ves v 5) or to the phospholipases (Pol d 1/Ves v 1) of the two vespids, or to both components at the same time. In 69% of cases, it was possible to define the most probable sensitizing insect, and in the rest, possible double sensitization could not be excluded. Vespula hyaluronidase was shown to have no additional value as regards the specificity of the assay.

CONCLUSIONS

The major allergens of P. dominulus' and Vespula vulgaris' venom, namely phoshpholipases and antigen 5s, are required to discriminate the probable sensitizing species in vespid-allergic patients.

Transesophageal pulmonary lobectomy with single transthoracic port assistance: study with survival assessment in a porcine model

BACKGROUND AND STUDY AIMS

Thoracoscopic pulmonary lobectomy is being performed in an increasing number of patients. The aims of the current study were to assess natural orifice transluminal endoscopic surgery (NOTES) as an alternative to transthoracic endoscopic surgery, and to test the feasibility of peroral transesophageal right upper pulmonary lobectomy with the assistance of a single transthoracic trocar.

METHODS

In 10 acute and 4 survival pigs, right upper pulmonary lobectomy was performed using a forward-viewing double-channel gastroscope and an operative thoracoscope with a 5-mm working channel inserted through a single transthoracic 12-mm) port. Time, safety, and feasibility of the following steps were recorded in all animals: esophagotomy, hilar dissection, individual ligation of the hilum elements, pulmonary lobectomy, and specimen retrieval. In the survival experiments, esophagotomy was closed using a reticulated laparoscopy suture device and an esophageal stent was placed. These animals were kept alive and monitored for 2 weeks.

RESULTS

Esophagotomy was performed safely in all animals (mean procedure duration 5.4 ± 1.7 minutes). Dissection of the right upper lobe hilum elements (bronchus, arteries, and veins) was carried out without adverse events. Individual ligation of the hilum elements was performed in all but two cases (time for dissection and ligation 44.2 ± 14.8 minutes). Lobectomy and specimen retrieval were completed in all animals (9.5 ± 3.1 minutes). Esophagotomy closure and stent placement were carried out in 20.0 ± 2.8 minutes in the survival animals. These animals fed normally and gained weight postoperatively without signs of disease. Endoscopic examination before necropsy revealed a pseudo-diverticulum in one animal, and wound dehiscence with confined collection/recess in the remaining animals.

CONCLUSIONS

Transesophageal right upper pulmonary lobectomy using single transthoracic trocar assistance is feasible and may represent a step towards scar-free pulmonary lobectomy.

New challenges in the analysis of gene transcription in bovine blastocysts

In the last years, enormous progress has been made in the analysis of gene transcription at the blastocyst stage. The study of gene expression at this early stage of development is challenging because of the very small amount of starting material, which limits the use of traditional mRNA analysis approaches such as Northern blot. Another problem is the difficulty for data normalization, particularly the identification of the best housekeeping gene with the lowest fluctuation under different developmental conditions. Moreover, the transcriptional analysis of embryo biopsies or individual embryos needs to take into consideration that the blastocyst is a transitional stage of development, which is composed of three different types of cells (trophoblast, epiblast and primitive ectoderm) with different patterns of gene expression, and that there are large differences between male and female blastocysts. In this review, we analyse the different specific and sensitive tools available to compare mRNA expression levels of specific genes at the blastocyst stage, and how the protocol and the analytical method used can influence the results dramatically. Finally, we describe future research challenges to identify candidate genes related to developmental competence of bovine blastocysts, not only in terms of pregnancy rates but also in relation to adverse long-term consequences in the adult animal.

[Levosimendan reduces mortality in cardiac surgery: a systematic review and meta-analysis]

OBJECTIVES

To evaluate whether Levosimendan has any impact on peri-operative mortality in cardiac surgery.

MATERIAL AND METHODS

A literature search was performed with the main purpose of looking for mortality in cardiac surgery. Data tabulated by both the fixed effects model and the random effects model were analysed based on the method by Peto. The statistical heterogeneity and inconsistency was estimated and quantified, as well as performing a sensitivity analysis to test the influence of individual studies on the overall result. All the calculations and statistical analyses were performed using the software; "Comprehensive Meta-Analysis" V2.0 and "StatsDirect statistical software" V 2.7.8. At the same time, possible publication bias was also determined.

RESULTS

A total of 169 articles were found, from which 13 studies were finally included in the meta-analysis; 12 randomised and one of them retrospective with paired data. The global analysis showed that the use of levosimendan was associated with a significant reduction in postoperative mortality.

CONCLUSIONS

The meta-analysis showed that the use of Levosimendan was associated with a reduction in mortality in patients subjected to cardiac surgery, although there is still no definitively clear evidence. Additional randomised and multicentre clinical studies, with a much larger number of patients are required, in which hospital mortality and mortality at 6 months are analysed as the primary outcomes.

Stress distribution analysis of seat and non-seat preparation design for orden cast post using 2D finite element method

The post is used to retain a core that supports the definitive restoration. One of the important factors in the prognosis of post-endodontic restoration system is the post space preparation design which effects to the distribution of stresses. The purpose of this study was to analyze the effect of post space preparation design at the cervical area of the root to the stress distribution on static loading using (two dimensions) finite element method. This was a numeric simulation study using two 2D digital models: seat and non-seat design of maxillary central incisors using commercial software of finite element. The procedures of pre-processing, solution, and post-processing were used to evaluate the distribution of internal stress caused by static loading 110 N which was applied at 135° angle with tooth longitudinal axis on the palatal surface of the core. Both models of restoration with cast post-core of Orden alloy were divided into 15,400 triangular elements. This study showed that the stress distribution from the loading location to the location of stress concentration and the value of maximum stress at cervical part of the root at non-seat design was lower than the seat design (seat design 3.69 times greater than non-seat). This study proved that non-seat design distributes stress better than seat design.