Artificial Space Weathering to Mimic Solar Wind Enhances the Toxicity of Lunar Dust Simulants in Human Lung Cells.

During NASA's Apollo missions, inhalation of dust particles from lunar regolith was identified as a potential occupational hazard for astronauts. These fine particles adhered tightly to spacesuits and were unavoidably brought into the living areas of the spacecraft. Apollo astronauts reported that exposure to the dust caused intense respiratory and ocular irritation. This problem is a potential challenge for the Artemis Program, which aims to return humans to the Moon for extended stays in this decade. Since lunar dust is "weathered" by space radiation, solar wind, and the incessant bombardment of micrometeorites, we investigated whether treatment of lunar regolith simulants to mimic space weathering enhanced their toxicity. Two such simulants were employed in this research, Lunar Mare Simulant-1 (LMS-1), and Lunar Highlands Simulant-1 (LHS-1), which were added to cultures of human lung epithelial cells (A549) to simulate lung exposure to the dusts. In addition to pulverization, previously shown to increase dust toxicity sharply, the simulants were exposed to hydrogen gas at high temperature as a proxy for solar wind exposure. This treatment further increased the toxicity of both simulants, as measured by the disruption of mitochondrial function, and damage to DNA both in mitochondria and in the nucleus. By testing the effects of supplementing the cells with an antioxidant (N-acetylcysteine), we showed that a substantial component of this toxicity arises from free radicals. It remains to be determined to what extent the radicals arise from the dust itself, as opposed to their active generation by inflammatory processes in the treated cells.

Developing core interprofessional competencies for community rehabilitation practitioners: findings from an Australian study.

This study aimed to determine the core competencies that underpin the practice of community rehabilitation (CR) practitioners working in a single state in Australia. Using a recursive and consultative methodology designed to build consensus, CR professionals, trainers, educators, and researchers developed a preliminary set of core interprofessional competencies that were considered essential to their practice. Data were collected in four main stages that engaged practitioners and experts in the CR field in the process of identifying, defining, validating, and endorsing a set of competencies. The first stage involved focus groups with 50 senior practitioners in metropolitan, rural/remote, regional, and indigenous communities. The second and third stages involved expert panels consisting of 20 trainers/educators, senior leaders, and scholars who refined, defined and validated the competency areas and developed statements that reflected the data.These statements formed the basis of a survey that was distributed to all current CR practitioners based in this state for endorsement, 40 of whom responded. Ten competencies emerged from this process. Although there are limitations to the application of competencies, they will have significant implications for the future training of CR practitioners who can transcend professional boundaries.

Gastric adenomas: relationship between clinicopathological findings, Helicobacter pylori infection, APC mutations and COX-2 expression.

Gastric adenomas are rare neoplastic growths characterized by localized polypoid proliferations of dysplastic epithelium that tend to progress to infiltrating adenocarcinoma. Therefore, the identification of molecular markers that could reliably recognize adenomas at risk of progression is advocated in the clinical management. In this study we investigated, in a series of gastric adenoma specimens from an area at high risk of gastric cancer, the relationship between clinicopathological characteristics of adenoma and Helicobacter pylori infection, APC mutational status, and COX-2 and the down-stream enzyme mPGES1 expression. Helicobacter pylori infection, detected in 24%, and 33% by histology and PCR analyses, respectively, did not show any relationship with growth pattern, localization, size, dysplasia grade and presence of synchronous cancer. Pathogenetic mutations of MCR region (codons 1269-1589) of the APC gene were detected only in one case corresponding to a single, small size, low grade, H. pylori-negative adenoma. The expression of COX-2 largely matched that of mPGES(1). Both were overexpressed in 79% of cases showing a relationship with high-grade dysplasia, size >10 mm and presence of a synchronous carcinoma. In conclusion, COX-2 may play a key role in the development and progression of gastric adenoma and could be an attractive target in the management of gastric adenoma at major risk of cancer development.

Patterns of K-ras mutation in colorectal carcinomas from Iran and Italy (a Gruppo Oncologico dell'Italia Meridionale study): influence of microsatellite instability status and country of origin.

BACKGROUND: K-ras mutations are a key step in colorectal cancer progression. Such mutations have been widely studied in case series from Western countries but there are few data on the rate and spectrum of mutations in tumors from countries where the epidemiological features of the disease are different. PATIENTS AND METHODS: Tumor samples from 182 Iranian colorectal cancer patients (170 sporadic cases and 12 HNPCC cases) were screened for K-ras mutations at codons 12, 13 and 61 by sequencing analysis. The cases were also characterized for microsatellite instability at mononucleotide repeats by PCR and fragment analysis, and classified according to microsatellite instability status. The frequency and the spectrum of K-ras mutations were compared with those observed in a series of colorectal cancer patients from Italy. RESULTS: K-ras mutations were observed in 68/182 (37.4%) cases. Mutation frequencies were similar in HNPCC-associated, sporadic MSI-H and sporadic microsatellite-stable (MSS) tumors. However, the G13D substitution was more frequent in HNPCC (3/4, 75%) and sporadic MSI-H (7/11, 63.6%) tumors compared to sporadic MSS tumors (11/53, 20.4%) (P <0.01). Comparison of mutations in the two series from Iran and Italy showed a significantly higher frequency of G13D among Italian patients. CONCLUSIONS: While the frequency of K-ras mutations could be similar, the mutational spectrum could be differentially influenced by genetic and environmental factors.

X-ray absorption spectroscopy of liquid methanol microjets: bulk electronic structure and hydrogen bonding network.

We have measured the X-ray absorption (XA) spectrum of liquid (298 K) methanol at the oxygen and carbon K edges. The 4a(1) orbital at the O K edge exhibits a pronounced sensitivity to the formation of intermolecular hydrogen bonds, with significant differences observed between the vapor and bulk spectra, whereas the C K edge reveals only subtle corresponding spectral changes. Comparison with DFT computed spectra of model methanol clusters indicates that the bulk liquid comprises long chains (n > 6) and rings of hydrogen-bonded monomers.

Aspects of column fabrication for packed capillary electrochromatography.

Various parameters have been evaluated to develop a process for optimization of column manufacture for packed capillary electrochromatography (CEC). Spherisorb ODS-1 was packed into 75 microm I.D. capillaries to establish a standard set of packing conditions to afford high-performance columns free of voids. Numerous silica-based packing materials including porous and non-porous reversed-phase and ion-exchange phases were employed to evaluate the applicability of the standard conditions. Success of column manufacture and performance demonstrate a relationship to the colligative properties of the packing materials under the applied conditions. Frequently encountered difficulties arising from inadequate column conditioning and void formation in the packed bed are identified and discussed.

Comparison of drug substance impurity profiles generated with extended length columns during packed-column SFC.

The current study assesses the effect of extending column length during gradient packed column sub/supercritical fluid chromatography (PCSFC) experiments on the detection of known and unknown impurities in a drug substance sample. Quantitative drug substance impurity profiles were generated and compared using multiple column PCSFC and HPLC conditions. Also, chromatographic figures of merit were estimated and compared for components of a standard mixture during PCSFC experiments, which used one column, four columns, and six columns in series.

Demonstrative validation study employing a packed column pressurized fluid chromatography method that provides assay, achiral impurities, chiral impurity, and IR identity testing for a drug substance.

Assay development, assay validation, and documentation are reported here for a single packed column pressurized fluid chromatographic/ultraviolet (UV) method that provides: (1) simultaneous detection and quantification for the chiral drug, the chiral impurity and seven achiral impurities; and (2) a Fourier transform infrared (FT-IR) spectrometric identification test result for the Searle drug substance sample, xemilofiban. The separation is achieved in less than 30 min with three columns in tandem and a gradient of CO2-CH3OH. The post-column flow is split between UV (assay) and FT-IR (identification). Precision and accuracy are consistent within figures of merit obtained by liquid chromatographic-ultraviolet assays on analogous drug substances. The reported procedure combines three typical drug substance tests into one test (e.g. chiral impurities, achiral impurities, and infrared identification).

Mechanism of misoprostol stabilization in hydroxypropyl methylcellulose.

The stability of misoprostol oil is significantly improved in a hydroxypropyl methylcellulose (HPMC) dispersion (1:100). In order to understand the enhanced stability of misoprostol oil in HPMC, the physical state of misoprostol oil in HPMC films was investigated using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and transmission IR (TIR). Further, to determine the effect of polymer structure and the mobility of both water and misoprostol on misoprostol stability, the rate of misoprostol degradation was investigated in the misoprostol/HPMC dispersion (1:100) at 55 degrees C. The water sorption isotherm of the dispersion at 55 degrees C was determined, at seven different relative humidities, ranging from zero to 81%. The DSC and DMA measurements indicated that misoprostol oil, up to 29% in dry weight, is molecularly dispersed in the glassy HPMC. The TIR studies showed no evidence of complexation between misoprostol and HPMC. Stability studies of the misoprostol/HPMC (1:100) dispersion indicated that the first-order rate constants for misoprostol degradation increased in a concave-up fashion as the water content of the dispersion increased. Below two percent water content, the rate of misoprostol degradation was found to be minimal. Overall, it is suggested that misoprostol is stabilized in the dispersion by being molecularly dispersed in HPMC. Further, the glassy state of HPMC should reduce the mobility of misoprostol and water, leading to a minimal rate of degradation for misoprostol at low moisture levels.

Use of cerebellar cGMP in the measurement and characterization of the diazepam/ethanol interaction.

The characterization and measurement of the benzodiazepine and ethanol interaction has been of major interest for many years. Various pharmacological and biochemical studies have been employed to investigate this interaction, which is believed to occur predominantly in the CNS, but localization of one particular brain area has not been investigated. This research employed the rat cerebellum as a site to study the diazepam/ethanol interaction. The measurement of cerebellar ethanol and diazepam, by gas chromatography, demonstrated an enhancement of diazepam levels by ethanol. Ethanol and diazepam, alone and in combination, displayed a significant depression of cerebellar 3',5'-Guanosine Cyclic Monophosphate (cGMP). The depression seen by the combination was significantly greater than the simple algebraic sum, but insignificantly different from the corrected algebraic sum. The double reciprocal plot of the data demonstrated a common ordinate intercept for the diazepam line and the diazepam/ethanol (2 g/kg) line, thus indicating a competitive mechanism of action.

Stabilization of misoprostol with hydroxypropyl methylcellulose (HPMC) against degradation by water.

The stability of misoprostol oil is significantly improved in a hydroxypropyl methylcellulose (HPMC) dispersion (1:100). In order to assess the effect of water on misoprostol stability, the rate of misoprostol degradation was investigated in the misoprostol/HPMC dispersion at 55 degrees C, along with the water sorption isotherm, under seven different relative humidity (RH) conditions ranging from 0 to 81%. The results indicated that the first-order rate constants of misoprostol degradation increased in a concave-up fashion as the water content of the dispersion increased. Below 30% relative humidity (approximately 2% water), the first-order rate constants of misoprostol degradation were found to be minimum. The results of the stability study were interpreted in terms of the changing structure of HPMC as it related to the mobility of water and misoprostol within the HPMC dispersion.

Ion-pairing high-performance liquid chromatographic method for the determination of 5-aminosalicylic acid and related impurities in bulk chemical.

An ion-pairing high-performance liquid chromatographic method has been developed for the determination of 5-aminosalicylic acid (5-ASA) bulk chemical in the presence of thirteen potential synthetic process impurities. In addition, the method is suitable for the determination of the in process intermediate, 5-nitrosalicylic acid. A selective method was achieved on a Hypersil-BDS reversed-phase column using 1-heptanesulfonic acid sodium salt as the ion-pairing reagent in a 0.08 M sodium phosphate buffer (pH 2) containing 0.005 M 1-heptanesulfonic acid sodium salt and 0.07 M sodium chloride-methanol-tetrahydrofuran (85:11:4, v/v/v) isocratic mobile phase. The method was validated using a multi-day, intra-laboratory protocol. The validation addressed linearity, accuracy, precision, sensitivity, and ruggedness of the method. The validated method characterizes the purity of 5-ASA bulk chemical.

Comparison of measures of visual acuity in infants: Teller acuity cards and sweep visual evoked potentials.

PURPOSE: This study compares the development of acuity in the same infants during one testing session using Teller acuity cards (TAC) and sweep visual evoked potentials (sVEP). We asked whether different testing methods in two centers would produce different developmental time courses. METHODS: Forty-eight infants were tested in two centers. The standard procedure for TAC was used. For sVEP acuity, the amplitude response curve derived from time-locked cortical activity was used to extrapolate to zero response, giving an acuity estimate for each infant. RESULTS: sVEP acuity was generally higher than TAC acuity. The rate of development was steeper for TAC than sVEP acuity with TAC starting at a much lower level. The ratio of sVEP to TAC acuity decreased exponentially with age reaching an asymptote of about 1.44 at 6 months. CONCLUSIONS: Results were indistinguishable between centers suggesting that comparison of acuity measures obtained using variations of these methods across centers is possible.

Evaluation of 1.5 microM reversed phase nonporous silica in packed capillary electrochromatography and application in pharmaceutical analysis.

Reversed-phase nonporous silica (RP-NPS) of 1.5 microm dp is employed to demonstrate rapid and efficient separations in packed capillary electrochromatography (CEC). Two methods for packing capillaries and two techniques to manufacture frits used to hold the packing in place are evaluated for their effect upon separation performance using polyaromatic hydrocarbons (PAHs) and polar neutral pharmaceutical compounds. Attention is given to conditioning of the packed capillaries for high efficiency separations without necessity for sodium dodecyl sulfate (SDS). Separation conditions for the nonporous materials were modified from those previously determined on porous reversed-phase silica. Feasibility for method development and validation of a parent pharmaceutical compound and related impurities in the range of 0.1-120% of a 5 mg/mL concentration was assessed and reported. An approach to improving detection sensitivity through use of large-bore capillaries is briefly discussed.

Method development in pharmaceutical analysis employing capillary electrochromatography.

Capillary electrochromatography (CEC) has been employed to explore method development for a series of structurally related polar neutral compounds of pharmaceutical relevance. Capillaries with dimensions of 75 microm ID x 25 cm length (34.5 cm total) were packed with Spherisorb ODS-1, Hypersil phenyl, and Hypersil MOS (all 3 microm particles) and were compared in the reversed-phase mode in order to determine which phase provided the best initial performance and thus serve as the phase of choice for additional method development experiments. The various separation parameters examined for their effect on efficiency, k', resolution, and linear velocity included percent and type of organic modifier, buffer concentration, voltage, and temperature. All separations were conducted with an acidic mobile phase (aqueous mobile phase component, pH 3.0). The separation efficiencies obtained were on the order of 200,000-260,000 plates/m, which equates to reduced plate heights of 1.22 for columns packed with Spherisorb ODS-1. Repeatable column-to-column separation performance was demonstrated.