Test-Retest Reliability of Postural Control Assessment on Biodex BioSway™.

Background: Recent protocols for posturographic assessment of postural control and balance have included head shake test conditions to challenge the vestibular contributions of postural control in an effort to increase the diagnostic accuracy of identifying individuals with impaired balance. However, evidence is limited regarding the test-retest reliability of such assessment protocols.

Purpose: The purpose of this study was twofold: to determine the test-retest reliability of postural control assessment on the Biodex Biosway™, an accessible and field expedient tool for posturographic assessment, and to determine the test-retest reliability of the Head Shake Sensory Interaction and Balance Test (HS-SIB), an adaptation of the modified Clinical Test of Sensory Interaction and Balance (mCTSIB) which adds two head shake conditions to challenge the vestibular contributions to postural control.

4-Ethoxybenzoic acid inhibits Staphylococcus aureus biofilm formation and potentiates biofilm sensitivity to vancomycin.

The adverse health effects of Staphylococcus aureus biofilm infections coupled with an increased global prevalence of antibiotic resistance highlight the need for novel anti-pathogenic, anti-biofilm compounds. The authors recently determined that ethyl-4-ethoxybenzoic acid (EEB) had anti-pathogenic, anti-biofilm activity. Based on this finding, a structure-activity analysis was undertaken to identify more effective compounds.

Ratcheting quasi-ballistic electrons in silicon geometric diodes at room temperature.

Ratcheting effects play an important role in systems ranging from mechanical socket wrenches to biological motor proteins. The underlying principle is to convert a fluctuating, unbiased force into unidirectional motion. Here, we report the ratcheting of electrons at room temperature using a semiconductor nanowire with precisely engineered asymmetry.

Galtonosides A-E: Antiproliferative and Antiplasmodial Cholestane Glycosides from .

An extract of from the Natural Products Discovery Institute showed moderate antiplasmodial activity, with an IC value less than 1.25 μg/mL. The two known cholestane glycosides and and the five new cholestane glycosides galtonosides A-E (-) were isolated after bioassay-directed fractionation.

Miniature spectral imaging device for wide-field quantitative functional imaging of the morphological landscape of breast tumor margins.

We have developed a portable, breast margin assessment probe leveraging diffuse optical spectroscopy to quantify the morphological landscape of breast tumor margins during breast conserving surgery. The approach presented here leverages a custom-made 16-channel annular photodiode imaging array (arranged in a 4 × 4 grid), a raster-scanning imaging platform with precision pressure control, and compressive sensing with an optimized set of eight wavelengths in the visible spectral range. A scalable Monte-Carlo-based inverse model is used to generate optical property [ ? s ? ( ? ) and ? a ( ? ) ] measures for each of the 16 simultaneously captured diffuse reflectance spectra.

Base and Nucleotide Excision Repair of Oxidatively Generated Guanine Lesions in DNA.

The well known biomarker of oxidative stress, 8-oxo-7,8-dihydroguanine, is more susceptible to further oxidation than the parent guanine base and can be oxidatively transformed to the genotoxic spiroiminodihydantoin (Sp) and 5-guanidinohydantoin (Gh) lesions. Incubation of 135-mer duplexes with single Sp or Gh lesions in human cell extracts yields a characteristic nucleotide excision repair (NER)-induced ladder of short dual incision oligonucleotide fragments in addition to base excision repair (BER) incision products. The ladders were not observed when NER was inhibited either by mouse monoclonal antibody (5F12) to human XPA or in XPC(-/-) fibroblast cell extracts.

A diffuse reflectance spectral imaging system for tumor margin assessment using custom annular photodiode arrays.

Diffuse reflectance spectroscopy (DRS) is a well-established method to quantitatively distinguish between benign and cancerous tissue for tumor margin assessment. Current multipixel DRS margin assessment tools are bulky fiber-based probes that have limited scalability. Reported herein is a new approach to multipixel DRS probe design, which utilizes direct detection of the DRS signal by using optimized custom photodetectors in direct contact with the tissue.

Toward new therapeutics for skin and soft tissue infections: propargyl-linked antifolates are potent inhibitors of MRSA and Streptococcus pyogenes.

Hospital- and community-acquired, complicated skin and soft tissue infections, often attributed to Staphylococcus aureus and Streptococcus pyogenes, present a significant health burden that is associated with increased health care costs and mortality. As these two species are difficult to discern on diagnosis and are associated with differential profiles of drug resistance, the development of an efficacious antibacterial agent that targets both organisms is a high priority. Herein we describe a structure-based drug development effort that has produced highly potent inhibitors of dihydrofolate reductase from both species.

Inhibition by methylated organo-arsenicals of the respiratory 2-oxo-acid dehydrogenases.

Inorganic arsenic that is ingested through drinking water or inhalation is metabolized by biological methylation pathways into organoarsenical metabolites. It is now becoming understood that this metabolism that was formerly considered to be detoxification may contribute as much or more to increasing the toxicity of arsenic. One proposed mode of the toxic action of arsenic and its organoarsenic metabolites is through its binding to proteins and inactivating their enzymatic activity.

Influence of substrate complexity on the diastereoselective formation of spiroiminodihydantoin and guanidinohydantoin from chromate oxidation.

Chromate is a human carcinogen with a poorly defined mechanism of DNA damage. In vitro and prokaryotic studies have shown that DNA damage may occur via the formation of the hydantoin lesions guanidinohydantoin (Gh) and spiroiminodihydantoin (Sp) from further oxidation of 8-oxo-7,8-dihydroguanine (8oxoG). The unusual structure of these lesions coupled with their enhanced mutagenicity make them attractive for study with regard to their role in chromate-induced cancer.

Chip-scale sensor system integration for portable health monitoring.

The revolution in integrated circuits over the past 50 yr has produced inexpensive computing and communications systems that are powerful and portable. The technologies for these integrated chip-scale sensing systems, which will be miniature, lightweight, and portable, are emerging with the integration of sensors with electronics, optical systems, micromachines, microfluidics, and the integration of chemical and biological materials (soft/wet material integration with traditional dry/hard semiconductor materials). Hence, we stand at a threshold for health monitoring technology that promises to provide wearable biochemical sensing systems that are comfortable, inauspicious, wireless, and battery-operated, yet that continuously monitor health status, and can transmit compressed data signals at regular intervals, or alarm conditions immediately.

Ascorbate is a pro-oxidant in chromium-treated human lung cells.

The human A549 lung cell line is used in this study as a model to evaluate chromium toxicity and mutagenesis since inhalation exposure of this metal gives rise to an epidemiology that indicates the lung as a target organ of chromium toxicity. Hexavalent chromium is considered the carcinogenic form of chromium, however it must be reductively activated following uptake into cells in order to react with intracellular constituents. We have previously established that the fluorescent dyes, dichlorofluorescein (DCF) and dihydrorhodamine, are effective indicators of the reductive activation of chromium and are sensitive measures of the formation of highly reactive chromium species (RCS) intracellularly.

Nei deficient Escherichia coli are sensitive to chromate and accumulate the oxidized guanine lesion spiroiminodihydantoin.

Growth inhibition and oxidized guanine lesion formation were studied in a number of base excision repair (BER) deficient Escherichia coli (E. coli) following chromate exposure. The only BER deficient bacterial strain that demonstrated significant growth inhibition by chromate, in comparison to its matched wild-type cell line, was the Nei deficient (TK3D11).

Guanine-specific oxidation of double-stranded DNA by Cr(VI) and ascorbic acid forms spiroiminodihydantoin and 8-oxo-2'-deoxyguanosine.

7,8-dihydro-8-oxoguanine (8-oxoG) is thought to be a major lesion formed in DNA by oxidative attack at the nucleobase guanine. Recent studies have shown that 8-oxoG has a lower reduction potential than the parent guanine and is a hot spot for further oxidation. Spiroiminodihydantoin (Sp) has been identified as one of these further oxidation products.

Recognition of the oxidized lesions spiroiminodihydantoin and guanidinohydantoin in DNA by the mammalian base excision repair glycosylases NEIL1 and NEIL2.

8-Oxoguanine (8-oxoG) is an unstable mutagenic DNA lesion that is prone to further oxidation. High valent metals such as Cr(V) and Ir(IV) readily oxidize 8-oxoG to form guanidinohydantoin (Gh), its isomer iminoallantoin (Ia), and spiroiminodihydantoin (Sp). When present in DNA, these lesions show enhanced base misincorporation over the parent 8-oxoG lesion leading to G --> T and G --> C transversion mutations and polymerase arrest.

Oxidative activation of the human carcinogen chromate by arsenite: a model for synergistic metal activation leading to oxidative DNA damage.

Human exposure to toxic metals and metalloids in the environment seldom occurs from a single pure compound. Most environmental exposure profiles are heterogeneous with co-exposure occurring coincident with multiple toxic metal species. This co-exposure to metals and metalloids in complex mixtures can result in a synergistic, additive or even depletive toxic response.

Oxidized guanine lesions as modulators of gene transcription. Altered p50 binding affinity and repair shielding by 7,8-dihydro-8-oxo-2'-deoxyguanosine lesions in the NF-kappaB promoter element.

A number of common promoter elements that drive transcription of redox sensitive genes have runs of guanines in their transcription factor recognition sequence. A paradox exists insomuch that the same guanine runs necessary for transcription factor recognition are thermodynamically prone to oxidative modification, potentially altering the binding affinity of transcription factors. 7,8-Dihydro-8-oxo-2'-deoxyguanosine (8-oxo-dG) is a common oxidative modification of guanine that is generated by a variety of metals and reactive oxygen species.

Guanine and 7,8-dihydro-8-oxo-guanine-specific oxidation in DNA by chromium(V).

The hexavalent oxidation state of chromium [Cr(VI)] is a well-established human carcinogen, although the mechanism of cancer induction is currently unknown. Intracellular reduction of Cr(VI) forms Cr(V), which is thought to play a fundamental role in the mechanism of DNA damage by this carcinogen. Two separate pathways of DNA damage, an oxidative pathway and a metal-binding pathway, have been proposed to account for the lesions observed in cell systems.