Structure of the stereocilia side links and morphology of auditory hair bundle in relation to noise exposure in the chinchilla

Stereocilia side links are directly involved in the maintenance of stereociliary bundle integrity in hair cells. The structure of the stereocilia side links and morphology of the auditory hair bundle in relation to noise exposure in the chinchilla was investigated by transmission electron microscopy. The outer hair cell (OHC) stereocilia side link was suggested to consist of extracellular, juxta-membrane and thin filamentous regions. Two beaded filaments were folded at their distal ends and fastened in one globule in the center between stereocilia. An intracellular, submembraneous layer appeared to form a bridge between the actin core and the extracellular, juxta-membrane region of the side link. In normal physiological conditions, most OHC stereocilia had a regular distribution of side links, forming a ‘zipper-like’ lattice between stereocilium shafts. Side links of the inner hair cell (IHC) stereocilia had a similar filamentous appearance, but were observed less commonly and had decreased structural organization compared to those of the OHC stereocilia. Ultrastructural analysis of OHC and IHC stereocilia showed that a large number of the side links could survive acoustic stimulation of 114 dB SPL for 2 hrs or 123 dB SPL for 15 min, that resulted in temporarily elevated hearing thresholds in all animals. Disarray, separation, close attachment and fusion of stereocilia were more frequently observed for IHC stereocilia and OHC stereocilia that were poorly connected or that lacked side links. Most disarrayed OHC and IHC stereocilia recovered to a normal erect state with restored orientation of the side links after 14–28 days, which correlated with near-complete recovery of auditory sensitivity. However, direct attachment of plasma membranes, ruptured links, fusion and blebs were seen on some stereocilia even after 28 days and appear to be permanent.     

Saccharomyces cerevisiae wine strains differing in copper resistance exhibit different capability to reduce copper content in wine

Two wine strains of Saccharomyces cerevisiae, characterized by a different degree of copper resistance, were tested in grape must fermentation in the presence of different copper concentrations. The sensitive strain SN9 was strongly affected by copper concentration (32 ppm, (32 mg/l)), whereas the resistant strain SN41 exhibited a good growth activity in presence of 32 ppm of copper and only a reduced activity in presence of 320 ppm. The different strain fermentation performance in response to the copper addition corresponded to a different capability to accumulate copper inside the cells. Both strains exhibited the capacity to reduce the copper content in the final product, eventhough a significantly greater reducing activity was exerted by the resistant strain SN41, which was able to reduce by 90% the copper concentration in the final product and to accumulate the metal in great concentrations in the cells. As high concentrations of copper can be responsible for wine alterations, the selection of S. cerevisiae strains possessing high copper resistance and the ability to reduce the copper content of wine has a great technological interest, in particular for the fermentation of biological products. From the results obtained, the technique proposed is not only suitable for the assay of copper residues in must, wine and yeast cells, but it also offers the advantage of easy sample preparation and low detection limit in the ppb (g/l) range.     

Coexistence trend contingent to Mediterranean oaks with different leaf habits

In a previous work we developed a mathematical model to explain the co‐occurrence of evergreen and deciduous oak groups in the Mediterranean region, regarded as one of the distinctive features of Mediterranean biodiversity. The mathematical analysis showed that a stabilizing mechanism resulting from niche difference (i.e. different water use and water stress tolerance) between groups allows their coexistence at intermediate values of suitable soil water content. A simple formal derivation of the model expresses this hypothesis in a testable form linked uniquely to the actual evapotranspiration of forests community. In the present work we ascertain whether this simplified conclusion possesses some degree of explanatory power by comparing available data on oaks distributions and remotely sensed evapotranspiration (MODIS product) in a large‐scale survey embracing the western Mediterranean area. Our findings confirmed the basic assumptions of model addressed on large scale, but also revealed asymmetric responses to water use and water stress tolerance between evergreen and deciduous oaks that should be taken into account to increase the understating of species interactions and, ultimately, improve the modeling capacity to explain co‐occurrence.     

Cryoballoon Ablation for Paroxysmal Atrial Fibrillation in Septuagenarians: a Prospective Study

Aims

To evaluate the effects of pulmonary vein isolation (PVI) in terms of feasibility, safety and success rate on a midterm follow-up period in septuagenarians undergoing ablation with the Arctic Front Cryoballoon for atrial fibrillation (AF).

Methods and Results

We prospectively enrolled 21 patients aged 70 years or older (14 male; age 73 ± 2.5 years) elected to circumferential PVI with the 28mm cryoballoon for symptomatic drug resistant paroxysmal AF. A total number of 82 pulmonary veins (PV) were evidenced. Successful isolation could be obtained in all 82 (100%) PV ostia at the end of procedure. No major complication occurred during procedure. At a mean follow-up of 11.5 ± 4.7 months following ablation, 62% of patients did not present recurrence of atrial arrhythmias.

Conclusion

Cryoballoon ablation may be feasible and safe in older patients. Moreover a large proportion of the latter did not present AF recurrence during follow-up.     

Development of a testing strategy for detecting embryotoxic hazards of chemicals in vitro by using embryonic stem cell models

The importance of developing in vitro tests for embryotoxicity is discussed, and ECVAM's work with its collaborators is summarised. Studies are in progress to find new endpoints for use in the scientifically validated embryonic stem (ES) cell test, so that the potential for chemical effects on endodermal, mesodermal and/or ectodermal differentiation can be identified. This involves, inter alia, the use of genetically modified ES cells.     

Combination of multiplex PCR and PCR-denaturing gradient gel electrophoresis for monitoring common sourdough-associated Lactobacillus species

A combination of denaturing gradient gel electrophoresis (DGGE) and a previously described multiplex PCR approach was employed to detect sourdough lactobacilli. Primers specific for certain groups of Lactobacillus spp. were used to amplify fragments, which were analyzed by DGGE. DGGE profiles obtained from Lactobacillus type strains acted as standards to analyze lactobacilli from four regional Abruzzo (central Italy) sourdoughs.     

Modifications of electrical potential in corrosive induced lesions of rat oesophagus

The Authors reproduced, experimentally, lesions of oesophageal mucosa on "Wistar" rats, using 1% and 2% solutions of HCl and NaOH. They studied DP modifications and observed that acid solutions produced a complete and persistent DP modification, while alkaline solutions produce DP inversions that diminish few days after the treatment.