We report a novel electrode composite comprising zinc phosphate within a multiwalled carbon nanotube paste electrode matrix which is applied for the detection of trace amounts of captopril (CAP) ...viasquare-wave adsorptive anodic stripping voltammetry (SWAdASV); to the best of our knowledge this is the first report on such a composite electrode. Under optimum experimental conditions, the peak current of CAP was found to be linear over the concentration range from 3.7 to 67 mu mol L super(-1) with a limit of detection of 0.1 mu mol L super(-1). The proposed method was applied for the successful determination of CAP in commercial tablet excipients and biological samples using the electroanalytical protocol evaluated against the laboratory standard iodometric procedure. Excellent comparability between the two is found suggesting that the former can replace the latter within laboratory settings or can be applied to in-the-field applications.
E.L., a modern-day Phineas Gage: Revisiting frontal lobe injury de Freitas, Pedro H.M.; Monteiro, Ruy C.; Bertani, Raphael ...
Lancet Regional Health - Americas (Online),
October 2022, 2022-Oct, 2022-10-00, 20221001, 2022-10-01, Letnik:
14
Journal Article
Recenzirano
Odprti dostop
How the prefrontal cortex (PFC) recovers its functionality following lesions remains a conundrum. Recent work has uncovered the importance of transient low-frequency oscillatory activity (LFO; < 4 ...Hz) for the recovery of an injured brain. We aimed to determine whether persistent cortical oscillatory dynamics contribute to brain capability to support ‘normal life’ following injury.
In this 9-year prospective longitudinal study (08/2012-2021), we collected data from the patient E.L., a modern-day Phineas Gage, who suffered from lesions, impacting 11% of his total brain mass, to his right PFC and supplementary motor area after his skull was transfixed by an iron rod. A systematic evaluation of clinical, electrophysiologic, brain imaging, neuropsychological and behavioural testing were used to clarify the clinical significance of relationship between LFO discharge and executive dysfunctions and compare E.L.´s disorders to that attributed to Gage (1848), a landmark in the history of neurology and neuroscience.
Selective recruitment of the non-injured left hemisphere during execution of unimanual right-hand movements resulted in the emergence of robust LFO, an EEG-detected marker for disconnection of brain areas, in the damaged right hemisphere. In contrast, recruitment of the damaged right hemisphere during contralateral hand movement, resulted in the co-activation of the left hemisphere and decreased right hemisphere LFO to levels of controls enabling performance, suggesting a target for neuromodulation. Similarly, transcranial magnetic stimulation (TMS), used to create a temporary virtual-lesion over E.L.’s healthy hemisphere, disrupted the modulation of contralateral LFO, disturbing behaviour and impairing executive function tasks. In contrast to Gage, reasoning, planning, working memory, social, sexual and family behaviours eluded clinical inspection by decreasing LFO in the delta frequency range during motor and executive functioning.
Our study suggests that modulation of LFO dynamics is an important mechanism by which PFC accommodates neurological injuries, supporting the reports of Gage´s recovery, and represents an attractive target for therapeutic interventions.
Fundação de Amparo Pesquisa Rio de Janeiro (FAPERJ), Universidade Federal do Rio de Janeiro (intramural), and Fiocruz/Ministery of Health (INOVA Fiocruz).
: In this study, we examined the effects of low levels and sub‐chronic exposure to methylmercury (MeHg) on butyrylcholinesterase (BuChE) activity in rats. Moreover, we examined the relationship ...between BuChE activity and oxidative stress biomarkers δ‐aminolevulinic acid dehydratase (δ‐ALA‐D) and malondialdehyde levels (MDA) in the same animals. Rats were separated into three groups (eight animals per group): (Group I) received water by gavage; (Group II) received MeHg (30 μg/kg/day) by gavage; (Group III) received MeHg (100 μg/kg/day). The time of exposure was 90 days. BuChE and ALA‐D activities were measured in serum and blood, respectively; whereas MDA levels were measured in plasma. We found BuChE and ALA‐D activities decreased in groups II and III compared to the control group. Moreover, we found an interesting negative correlation between plasmatic BuChE activity and MDA (r = −0.85; p < 0.01) and a positive correlation between plasmatic BuChE activity and ALA‐D activities (r = 0.78; p < 0.01), thus suggesting a possible relationship between oxidative damage promoted by MeHg exposure and the decrease of BuChE activity. In conclusion, long‐term exposure to low doses of MeHg decreases plasmatic BuChE activity. Moreover, the decrease in the enzyme is strongly correlated with the oxidative stress promoted by the metal exposure. This preliminary finding highlights a possible mechanism for MeHg to reduce BuChE activity in plasma. Additionally, this enzyme could be an auxiliary biomarker on the evaluation of MeHg exposure.
Feline herpesvirus type 1 infection affects domestic cats, causing mainly upper respiratory tract diseases. Although this infection has been described in captive and free-ranging wild felids from ...Europe, Asia, North America, and Africa, no information is available on its occurrence among wild felids of Brazil. In this study, 250 serum samples of six species of Brazilian captive wild felids (Leopardus tigrinus, Leopardus wiedii, Herpailurus yaguarondi, Puma concolor, Leopardus pardalis, and Panthera onca) were examined for neutralizing antibodies to feline herpesvirus type 1. Positive sera were found in 72% of L. tigrinus samples, 15% of L. wiedii, 6% of L. pardalis, 8% of H. yaguarondi, 18% of P. concolor, and 14% of P. onca. The relatively low percentages of seropositivity and low antibody titers found among the last five species suggest that feline herpesvirus type 1 does not circulate extensively among these animals. Nevertheless, quarantine, serologic screening, and vaccination of newly introduced felids is recommended in zoos in order to prevent virus transmission and outbreaks of the disease among wild felids kept in captivity.
A factorial design applied in a voltammetric stripping method for the measurement of Ag(I) in natural water is described. The procedure is based on the effective pre-concentration of silver ions on ...electrode surface. The calibration graph was linear in the silver concentration range from 7.92 x 10"7 to 1.07 x 10"5 mol L"1 with a detection limit of 3.81 x 10-7 mol L-1. The determination of Ag(I) in natural water samples was carried out satisfactory with the proposed electrode.
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