Highly sensitive square wave voltammetric method for determination of brucine in artificial urine samples based on choline chloride modified glassy carbon electrode.

This paper demonstrates a highly sensitive Voltammetric sensor for determination of brucine (BRU) in artificial urine sample based on choline chloride modified glassy carbon electrode (ChCl/GCE). The simple and cost effective modification was performed by electrodeposition of choline chloride on glassy carbon electrode surface using cyclic voltammetry technique. The modified electrode surface was characterized by electrochemical, spectroscopic and microscopic imaging. The electrode yields a well-resolved peak current for the irreversible oxidation of brucine in the first scan and a pair of quasi-reversible peaks during the second scan. The CV study indicates that brucine undergoes an adsorption controlled electrochemical process with equal number of electrons and protons transfer on the ChCl/GCE. The SWV result shows that the reduction peak current of BRU at the ChCl/GCE was linear in the range of 0.001 µM-10 µM with limit of detection 8 × 10-5 µM, limit of quantification 2.6 × 10-4 µM and sensitivity of 116.4 µA/µM. The ChCl/GCE also showed an excellent selectivity, reproducibility and long-time stability towards the electrochemical reduction of Brucine. Moreover, the practical applicability of the fabricated ChCl/GCE was examined in order to determine BRU in artificial urine samples with recovery ranging from 95.5 to 102.7%. The validity of the developed method was confirmed by chromatographic techniques, high-performance liquid chromatography (HPLC) and the results obtained are consistent the HPLC method.

The presence and impact of biofilm-producing staphylococci in atopic dermatitis.

IMPORTANCE: Atopic dermatitis (AD) is thought to be a double-hit phenomenon with an unknown environmental component and a genetic abnormality likely centered on the filaggrin gene. Biologically, the presence of Staphylococcus aureus in AD was reported more than 2 decades ago, but the relationship to AD has been elusive. OBJECTIVE: To explore the bacteria that produce the biofilms in the lesions of AD and the response of the innate immune system to these biofilm occlusions of the sweat ducts by specifically evaluating Toll-like receptor 2. DESIGN, SETTING, AND PARTICIPANTS: University hospital dermatologic clinic study involving the environmental component related to the characterization, correlation, and impact of staphylococci and their biofilms in AD. We processed routine skin swabs from lesional and nonlesional skin from 40 patients with AD and performed scrapings and biopsies. We also obtained 20 samples from controls (10 inflamed skin samples and 10 normal skin samples). EXPOSURES: Gram staining, bright-field microscopy, hematoxylin and eosin, periodic acid-Schiff, Congo red, and light microscopy. MAIN OUTCOMES AND MEASURES: Association of staphylococcal biofilms with AD pathogenesis. RESULTS: All AD-affected samples contained multidrug-resistant staphylococci, with S aureus (42.0%) and Staphylococcus epidermidis (20.0%) as the predominant species. All isolates were positive for extracellular polysaccharide and biofilm (85.0% strong biofilm producers and 15.0% moderately to weakly positive). Polymerase chain reaction revealed the biofilm-mediating icaD (93.0%) and aap (12.5%) genes in the isolates (some contained both). We also examined tissues for microbial identification, extracellular biomass formation, biofilm formation, and staphylococcal biofilm in skin tissues. Occlusion of sweat ducts with periodic acid-Schiff-positive and Congo red-positive material was noted on microscopic tissue examination. Toll-like receptor 2 was shown to be activated in AD lesional skin (immediately proximal to the sweat ducts), which likely led to the initiation of proteinase-activated receptor 2-mediated pruritus and MyD88-mediated spongiosis. CONCLUSIONS AND RELEVANCE: Biofilm formation by AD-associated staphylococci almost certainly plays a major role in the occlusion of sweat ducts and leads to inflammation and pruritus. We believe the environmental hit in AD relates to staphylococci and their biofilms, which occlude sweat ducts.

The oldest new finding in atopic dermatitis: subclinical miliaria as an origin.

IMPORTANCE: In 1947, Sulzberger and colleagues published a micrograph of a blocked acrosyringium in a patient with atopic dermatitis (AD), believing that it had a large role in the disease process. Lacking appropriate probes, they could not confirm the finding. OBJECTIVE: To confirm the observations by Sulzberger et al on the blockage of sweat ducts in AD in pathologic specimens. DESIGN AND SETTING: Biopsy specimens diagnostic of various inflammatory diseases and with a secondary differential diagnosis of eczema were evaluated at an academic medical center. EXPOSURES: Evidence of ductal obstruction in each specimen was examined following staining with hematoxylin-eosin, periodic acid-Schiff, and Gram stain. MAIN OUTCOMES AND MEASURES: Comparison of biopsy specimens with control specimens and additional controls consisting of noninflamed skin. RESULTS: Using 36 biopsy specimens, this study confirmed the observations by Sulzberger et al on the blockage of sweat ducts in AD. Blocked acrosyringia were noted in each specimen on routine staining with hematoxylin-eosin. The study also confirmed the findings by earlier investigators about the blockage of sweat ducts in miliaria, showing eosinophilic material in the ducts that was positive for periodic acid-Schiff. Previous researchers also observed bacteria in the blockages, and this study demonstrated the same findings in AD, rather than miliaria. CONCLUSION AND RELEVANCE: Subclinical miliaria may be the earliest change in AD and likely initiates the process that causes intense pruritus.