A new interpretation of P300 responses upon analysis of coherences

Previous studies on cognitive dynamics showed that oscillatory responses of P300 are composed of mainly delta and theta responses. In the present study, for the first time, the long-distance intra-hemispheric event related coherence (auditory oddball paradigm) and evoked coherence (simple sound) were compared in order to evaluate the effects of cognitive tasks on the long-distance coherences. Seventeen healthy subjects (8 female, 9 male) were included in the study. The coherence was analyzed for delta (1–3.5 Hz), theta (4–7.5 Hz) and alpha (8–13 Hz) frequency ranges for (F₃-P₃, F₄-P₄, F₃-T₇, F₄-T₈, F₃-O_1, F₄-O₂) electrode pairs. The coherence to target responses were higher than the non-target and simple auditory response coherence. This difference is significant for the delta coherence for both hemispheres and for theta coherences over the left hemisphere. The highest coherences were recorded at fronto-temporal locations for all frequency bands (delta, theta, alpha). Furthermore, fronto-parietal coherences were higher than the fronto-occipital coherences for all frequency bands (delta, theta, alpha).These results show that the fronto-temporal and fronto-parietal connections are most relevant for the identification of the target signal. This analysis open the way for a new interpretation of dynamic localization results during cognitive tasks.     

Anterolateral thigh flap in the treatment of postburn flexion contractures of the knee

The use of the anterolateral thigh fasciocutaneous flap in the reconstruction of soft-tissue defects around the knee among burn patients is described. The anterolateral thigh fasciocutaneous flap was used for eight patients (all male; mean age, 45 years; age range, 32 to 60 years). Flexion contracture was observed for seven patients with unhealed wounds and one patient with a healed burn wound. The anterolateral thigh flap was used as a free flap for six patients and as a distally based island flap for two patients. The flaps ranged from 8 to 17 cm in width and from 12 to 30 cm in length. Seven flaps were based on a musculocutaneous perforator, and two of them were thinned before transfer to the defect. A true septocutaneous perforator was observed in only one case. The mean follow-up period was 12.5 months (range, 3 to 23 months). Only one flap exhibited distal superficial necrosis, which did not compromise the final result. All patients returned to ambulatory status in 15 to 22 days. Extensor splints were applied to prevent mobilization of the skin graft at the flap donor site for only 7 days. The anterolateral thigh flap has many advantages for the reconstruction of postburn flexion contracture of the knee, as follows: (1) very large thin flaps can be elevated, (2) the two-team approach is possible, (3) color and texture matches are good, (4) the donor-site scar can be easily hidden, and (5) the technique allows early mobilization and patients can return to normal daily activity in a short time. Free or distally based anterolateral thigh flaps are a good choice, both aesthetically and functionally, for the reconstruction of soft-tissue defects of the knee region.     

Neurotoxic,cytotoxic, apoptotic and antiproliferative effects of some marine algae extracts on the NA2B cell line

Oxidative stress contributes to cancer pathologies and to apoptosis. Marine algae exhibit cytotoxic, antiproliferative and apoptotic effects; their metabolites have been used to treat many types of cancer. We investigated in culture extracts of Petalonia fascia, Jania longifurca and Halimeda tuna to determine their effects on mouse neuroblastoma cell line, NA2B. NA2B cells were treated with algae extracts, and the survival and proliferation of NA2B cells were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The effects of algae extracts on oxidative stress in NA2B cells also were investigated using nitric oxide synthase (NOS) immunocytochemistry and apoptosis was assessed using terminal deoxynucleotidyl transferase dUTP nick end labeling. We observed significant neurite inhibition with moderate damage by the neurotoxicity-screening test (NST) at IC₅₀ dilutions of the extracts. MTT demonstrated that J. longifurca extracts were more toxic than P. fascia and H. tuna extracts. We found an increase of endothelial and inducible NOS immunostaining for oxidative stress and TUNEL analysis revealed increased apoptosis after application of extract. Our findings suggest that the algae we tested may have potential use for treatment of cancer.     

Immunogenicity of recombinant Babesia microti hsp70 homologue in mice

A Babesia microti hsp70 homologue was cloned, expressed in a prokaryotic system and tested in a pilot study for protection against lethal challenge. Results showed that 30% of the mice inoculated with recombinant protein (rBm hsp70) survived challenge, while all of the controls died. Evidence of antibody response to the hsp homologue was detected by Western blot analysis, but no protection was imparted through passive transfer of convalescent serum. Passively transferred spleen cells, from mice which survived challenge, also failed to impart protection. The mechanism of partial immunity suggested by these observations remains to be elucidated.     

Adaptation of Borrelia burgdorferi in the vector and vertebrate host

Borrelia burgdorferi sensu lato is the causative agent of Lyme disease, which afflicts both humans and some domestic animals. B. burgdorferi, a highly evolved extracellular pathogen, uses several strategies to survive in a complex enzootic cycle involving a diverse range of hosts. This review focuses on the unique adaptive features of B. burgdorferi, which are central to establishing a successful spirochetal infection within arthropod and vertebrate hosts. We also discuss the regulatory mechanisms linked with the development of molecular adaptation of spirochetes within different host environments.     

Assessing human impact despite uncertainty:viability of the northern spotted owl metapopulation in the northwestern USA

We demonstrate the effect of uncertainty (resulting from lack of information or measurement error) on the assessment of human impact, with an analysis of the viability of the northern spotted owl throughout its range in the United States. We developed a spatially-explicit, stage-structured, stochastic metapopulation model of the northern spotted owl throughout its range in the United States. We evaluated the viability of the metapopulation using measures such as risk of decline and time to extinction. We incorporated uncertainty in the form of parameter ranges, and used them to estimate upper and lower bounds on the estimated viability of the species. We analysed the effect of this type of uncertainty on the assessment of human impact by comparing the species' viability under current conditions and under an assumed loss of spotted owl habitat in the next 100 years. The ranges of parameters were quite large and resulted in a wide range of risks of extinction. Despite this uncertainty, the results were sensitive to parameters related to habitat loss: under all assumptions and combinations of parameters, the model predicted that habitat loss results in substantially higher risks of metapopulation decline. This result demonstrated that even with relatively large uncertainties, risk-based model results can be used to assess human impact reliably.