Detection of picomolar levels of interleukin-8 in human saliva by SPR

Researchers at UCLA have discovered that the levels of interleukin-8 (IL-8) protein in the saliva of healthy individuals and patients with oropharyngeal squamous cell carcinoma (OSCC) are 30 pM and 86 pM, respectively. In this study, we present the development of the first immunoassay for the quantification of picomolar IL-8 concentrations in human saliva using Biacore surface plasmon resonance (SPR) in a microfluidic channel. A sandwich assay using two monoclonal antibodies, which recognize different epitopes on the antigen (IL-8), was used. Only 13 minutes were required to determine the quantity of pure IL-8 added to just 100 microL of either buffer or saliva-based samples. The limit of detection (LOD) of this immunoassay in buffer was 2.5 pM, and the precision of the response for each concentration was <3% of the coefficient of variation. When first analyzing the saliva supernatants, non-specific binding to the surface was observed. By adding carboxymethyl dextran sodium salt (10 mg mL(-1)) to compete with the surface dextran and primary antibody for non-specific interactions, the signal to noise ratio was greatly improved. The LOD of this immunoassay in saliva was 184 pM. A minimum concentration of 250 pM of exogenous IL-8 could then be consistently detected in a salivary environment. The precision of the response for each IL-8 concentration tested was <7% of the coefficient of variation. Diagnostic sensitivity for oral cancer can be achieved by pre-concentrating the saliva samples 10 fold prior to SPR analysis, making the target levels of IL-8 300 pM for healthy individuals and 860 pM for oral cancer patients.     

Purifying the masses: integrating prepurification quality control, high-throughput LC/MS purification, and compound plating to feed high-throughput screening

In this paper we report using a parallel, four-channel HPLC/MUX/MS purification system, the Purification Factory, to purify thousands of compounds destined for high-throughput screening in a single month. The maximum sample throughput during this 20-workday month was 704 samples/day. Since this purification throughput exceeded the postpurification sample and data handling capabilities provided by commercial solutions, a custom-integrated solution was designed to address these shortcomings. In this paper we detail the key improvements in automation, solvent handling, and sample handling logistics implemented to sustain a mean throughput of 528 samples/day over a multimonth time period.     

Correlation between liver iron content and magnetic resonance imaging in rats

Currently, serum ferritin concentration is the best noninvasive estimator of liver iron content. This study investigated the ability of magnetic resonance imaging to determine hepatic iron concentration. Fisher rats were treated with either parenteral iron to increase levels or phlebotomy to lower them and achieved a wide range of liver iron concentrations. Rats were imaged using a clinical whole body scanner at 1.5 Tesla with a 15-cm Helmholtz surface coil and a 23-cm field of view. The ratio of signal intensity of liver to skeletal muscle from images of the live intact rats correlated well with chemically measured iron concentration of the liver (r = −.89, p < .0001, linear regression analysis). Transverse relaxation rates (1/calculated T₂ relaxation times) also correlated with liver iron content (r = .66, p < .0001). The observation of a significant correlation between liver iron content and both signal intensities and T₂ relaxation rates, obtained by magnetic resonance imaging, may have considerable clinical relevance. If adapted to humans, this technique would have obvious applications in the diagnosis and management of diseases associated with iron overload as well as in the investigation of the overall role of iron in various human liver diseases.     

Solution of the poisson equation related to a boundary-value problem for the sphere

Zusammenfassung Es werden Lösungen der Poissonschen Differentialgleichungen in den Bereichen innerhalb und ausserhalb einer Sphäre, die gewisse Grenzbedingungen an der Fläche der Sphäre erfüllen, gesucht. Solche Lösungen werden schliesslich als Funktion partikulärer Integrale der Differentialgleichungen ausgedrückt. Ihre Anwendung auf die theoretische Physik wird anschliessend behandelt.     

Synthesis and magnetic properties of wheel-shaped [Mn12] and [Fe6] complexes

The reactions of the ligands N-methyldiethanol amine and N-ethyldiethanol amine (abbreviated H(2)mdea and H(2)edea, respectively) with [Mn(12)O(12)(O(2)CCH(3))(16)(H(2)O)(4)] yield novel dodecanuclear wheel-shaped products. The capability of the ligands H(2)mdea and H(2)edea to support wheel structures in metals other than Mn is demonstrated with the crystal structure of a new hexanuclear ferric wheel.     

High resolution FTIR spectroscopy of pentafluoroethane: perturbations in the Coriolis doublet of ν4 and ν13

The FTIR spectrum of pentafluoroethane (R125) was measured in the mid infrared region from 900 to 4000 cm⁻¹. Vibrational assignments for R125 are revised by comparison of previous and current experimental data with ab initio calculations at both the MP2/6-311+(d,p) and B3LYP/TZV+(3df,3p) levels of theory. High resolution FTIR spectra were recorded at room temperature and in an enclosive flow cell at a rotational temperature of 140 K. The cold spectrum was sufficiently resolved to enable rovibrational analyses of the overlapping ν₄ (1200.7341 cm⁻¹) and ν₁₃ (1223.3 cm⁻¹) bands, which have a/c hybrid and b-type character, respectively. Ground state combination differences were used to confirm assignment of 2375 lines to ν₄ (J_max = 86, K_{a max} = 50) and 2921 lines to ν₁₃ (J_max = 60, K_{a max} = 54). Effective rotational and centrifugal distortion constants were determined for ν₄, and the polarization ratio was found to be . Severe Coriolis perturbations prevent any satisfactory fit to the ν₁₃ band.     

Color of shock waves in photonic crystals

Unexpected and stunning new physical phenomena result when light interacts with a shock wave or shocklike dielectric modulation propagating through a photonic crystal. These new phenomena include the capture of light at the shock wave front and reemission at a tunable pulse rate and carrier frequency across the band gap, and bandwidth narrowing as opposed to the ubiquitous bandwidth broadening. To our knowledge, these effects do not occur in any other physical system and are all realizable under experimentally accessible conditions. Furthermore, their generality make them amenable to observation in a variety of time-dependent photonic crystal systems, which has significant technological implications.     

Spectroscopic studies of anion complexes and clusters: a microscopic approach to understanding anion solvation

Recent infrared spectroscopic studies of negatively charged clusters in the gas phase have furnished new information on non-covalent bonds between anions and neutral molecules, and provided fresh perspectives on the microscopic details of anion solvation. We describe the central spectroscopic techniques employed for obtaining infrared spectra of mass-selected solvated anions in the gas phase, and illustrate recent progress by describing studies of simple halide-H2 dimers, and larger clusters in which up to 9 C2H2 molecules are attached to a Cl- anion.