Combination of Hansen Robotic system with cryocatheter in a challenging parahisian accessory pathway ablation

A perceived distinctive feature of cryoablation is the stability (cryoadherence) of the catheter tip during cold temperatures at the desired location, even during tachycardia. We report the case report of a young patient with a parahisian accessory pathway where stability of the ablation catheter was not achieved despite using the cryocatheter with a steerable sheath. Ultimately, stability at the desired location was achieved robotically by means of Hansen system (Hansen Medical, Mountain View, CA, USA).     

Cancer risk from chronic exposures to chemicals and radiation: a comparison of the toxicological reference value with the radiation detriment

This article aims at comparing reference methods for the assessment of cancer risk from exposure to genotoxic carcinogen chemical substances and to ionizing radiation. For chemicals, cancer potency is expressed as a toxicological reference value (TRV) based on the most sensitive type of cancer generally observed in animal experiments of oral or inhalation exposure. A dose–response curve is established by modelling experimental data adjusted to apply to human exposure. This leads to a point of departure from which the TRV is derived as the slope of a linear extrapolation to zero dose. Human lifetime cancer risk can then be assessed as the product of dose by TRV and it is generally considered to be tolerable in a 10^–6–10^–4 range for the public in a normal situation. Radiation exposure is assessed as an effective dose corresponding to a weighted average of energy deposition in body organs. Cancer risk models were derived from the epidemiological follow-up of atomic bombing survivors. Considering a linear-no-threshold dose-risk relationship and average baseline risks, lifetime nominal risk coefficients were established for 13 types of cancers. Those are adjusted according to the severity of each cancer type and combined into an overall indicator denominated radiation detriment. Exposure to radiation is subject to dose limits proscribing unacceptable health detriment. The differences between chemical and radiological cancer risk assessments are discussed and concern data sources, extrapolation to low doses, definition of dose, considered health effects and level of conservatism. These differences should not be an insuperable impediment to the comparison of TRVs with radiation risk, thus opportunities exist to bring closer the two types of risk assessment.

     

Techniques for the detection of pathogenic Cryptococcus species in wood decay substrata and the evaluation of viability in stored samples

In this study, we evaluated several techniques for the detection of the yeast form of Cryptococcus in decaying wood and measured the viability of these fungi in environmental samples stored in the laboratory. Samples were collected from a tree known to be positive for Cryptococcus and were each inoculated on 10 Niger seed agar (NSA) plates. The conventional technique (CT) yielded a greater number of positive samples and indicated a higher fungal density [in colony forming units per gram of wood (CFU.g^-1) ] compared to the humid swab technique (ST). However, the difference in positive and false negative results between the CT-ST was not significant. The threshold of detection for the CT was 0.05.10³ CFU.g^-1, while the threshold for the ST was greater than 0.1.10³ CFU^-1. No colonies were recovered using the dry swab technique. We also determined the viability of Cryptococcus in wood samples stored for 45 days at 25ºC using the CT and ST and found that samples not only continued to yield a positive response, but also exhibited an increase in CFU.g^-1, suggesting that Cryptococcus is able to grow in stored environmental samples. The ST.1, in which samples collected with swabs were immediately plated on NSA medium, was more efficient and less laborious than either the CT or ST and required approximately 10 min to perform; however, additional studies are needed to validate this technique.     

Alien aquatic vascular plants in Hungary (Pannonian ecoregion): Historical aspects,data set and trends

Estimating the extent of biological invasions is critical in predicting the effect of exotic species. We investigated the occurrence and number of alien freshwater plants and give information on the composition of alien aquatic flora, their trend in time, invasion pathway, and their invasive character.     

Anatomical and ultrastructural examination of adventitious root formation in stem slices of apple

Adventitious root formation in vitro in 1-mm stem slices cut from microshoots of apple cv. Jork 9 was studied using light and electron microscopy. When indole-3-butyric acid (IBA) had been added to the medium, starch grains accumulated during the first 24 h of culture in cells of the cambial region and in cells in the vicinity of vascular tissue and in the primary rays. This accumulation occurred only in the basal part of explants. After that, the nuclei in these cells were activated, and the density of the cytoplasm and the number of cell organelles increased, whereas starch was broken down. Cambium cells started to divide transversely and at 96 h, after several divisions, a continuous ring of isodiametric cytoplasmic cells had appeared around the xylem near the basal cutting surface. The cells in this ring were rich in cell structures, and did not contain large starch grains and a central vacuole. Root meristemoids regenerated from the portions of the ring that were localized in the primary rays. From the other cells in the ring, callus developed. The meristemoids did not grow into the direction of the epidermis as in shoots, but along the vascular bundles. After emergence from the cutting surface, the meristemoids were transformed into small, dome-like primordia. They developed a typical root apex with root cap, root ground meristem and tracheid connection with shoot vascular tissue. This revised version was published online in July 2006 with corrections to the Cover Date.     

Host Cell Poly(ADP-Ribose) Glycohydrolase Is Crucial for Trypanosoma cruzi Infection Cycle

Trypanosoma cruzi, etiological agent of Chagas’ disease, has a complex life cycle which involves the invasion of mammalian host cells, differentiation and intracellular replication. Here we report the first insights into the biological role of a poly(ADP-ribose) glycohydrolase in a trypanosomatid (TcPARG). In silico analysis of the TcPARG gene pointed out the conservation of key residues involved in the catalytic process and, by Western blot, we demonstrated that it is expressed in a life stage-dependant manner. Indirect immunofluorescence assays and electron microscopy using an anti-TcPARG antibody showed that this enzyme is localized in the nucleus independently of the presence of DNA damage or cell cycle stage. The addition of poly(ADP-ribose) glycohydrolase inhibitors ADP-HPD (adenosine diphosphate (hydroxymethyl) pyrrolidinediol) or DEA (6,9-diamino-2-ethoxyacridine lactate monohydrate) to the culture media, both at a 1 µM concentration, reduced in vitro epimastigote growth by 35% and 37% respectively, when compared to control cultures. We also showed that ADP-HPD 1 µM can lead to an alteration in the progression of the cell cycle in hydroxyurea synchronized cultures of T. cruzi epimastigotes. Outstandingly, here we demonstrate that the lack of poly(ADP-ribose) glycohydrolase activity in Vero and A549 host cells, achieved by chemical inhibition or iRNA, produces the reduction of the percentage of infected cells as well as the number of amastigotes per cell and trypomastigotes released, leading to a nearly complete abrogation of the infection process. We conclude that both, T. cruzi and the host, poly(ADP-ribose) glycohydrolase activities are important players in the life cycle of Trypanosoma cruzi, emerging as a promising therapeutic target for the treatment of Chagas’ disease.     

Liver Accumulation of Plasmodium chabaudi-Infected Red Blood Cells and Modulation of Regulatory T Cell and Dendritic Cell Responses

It is postulated that accumulation of malaria-infected Red Blood Cells (iRBCs) in the liver could be a parasitic escape mechanism against full destruction by the host immune system. Therefore, we evaluated the in vivo mechanism of this accumulation and its potential immunological consequences. A massive liver accumulation of P. c. chabaudi AS-iRBCs (Pc-iRBCs) was observed by intravital microscopy along with an over expression of ICAM-1 on day 7 of the infection, as measured by qRT-PCR. Phenotypic changes were also observed in regulatory T cells (Tregs) and dendritic cells (DCs) that were isolated from infected livers, which indicate a functional role for Tregs in the regulation of the liver inflammatory immune response. In fact, the suppressive function of liver-Tregs was in vitro tested, which demonstrated the capacity of these cells to suppress naive T cell activation to the same extent as that observed for spleen-Tregs. On the other hand, it is already known that CD4+ T cells isolated from spleens of protozoan parasite-infected mice are refractory to proliferate in vivo. In our experiments, we observed a similar lack of in vitro proliferative capacity in liver CD4+ T cells that were isolated on day 7 of infection. It is also known that nitric oxide and IL-10 are partially involved in acute phase immunosuppression; we found high expression levels of IL-10 and iNOS mRNA in day 7-infected livers, which indicates a possible role for these molecules in the observed immune suppression. Taken together, these results indicate that malaria parasite accumulation within the liver could be an escape mechanism to avoid sterile immunity sponsored by a tolerogenic environment.     

Fluorescence banding in four species of Microtidae: an analysis of the evolutive changes of the constitutive heterochromatin

Three different fluorochrome and specific counterstain combination (DAPI/AMD, DA/DAPI and CMA/DA) treatments were applied to the chromosomes of four Microtidae (Rodentia) species. The results complete the data obtained in our previous paper (Burgos, M., Jiménez, R., & Dìaz de la Guardia, R., Genome 30:540–546, 1988) and prove that the changes in the constitutive heterochromatin in the evolution of the karyotypes of these species are not only due to gain or loss of heterochromatin, but are qualitative with respect to their nucleotide composition, repeated base pair organization or DNA-protein complex modification. These variations lead to the differential response to the fluorescence dye combinations used.