Comparison of reversed-phase column materials for high-performance liquid chromatography of proteins

Nine reversed-phase materials with various bonded phases from different suppliers were studied for the separation of hydrophilic proteins with two solvent systems. Protein retention, resolution and recovery were not correlated with the nature of the hydrocarbonaceous ligand. Peak volumes increased with molecular weight, which led to broad, irregular peaks for the larger proteins on some columns. Four columns that performed equally well were selected for the purification of hydrophobic Sendai virus membrane proteins. In this case, more distinct differences were found between columns. Recovery of the membrane proteins strongly depended on the combination of column and solvent systems.     

Magnetic resonance imaging of pediatric spinal dysraphism

Thirty pediatric patients with spinal dysraphism were studied with magnetic resonance imaging. A variety of dysraphic anomalies were visualized, including syringohydromyelia, tethered cord, widened spinal canal, meningomyelocele, lipomyelomeningocele, lipomeningocele, intraspinal lipoma, congenital dermal sinus tract, and scoliosis. In 29 of 30 cases, MRI diagnostically visualized spinal cord and dysraphic anatomy. A combination of T1-weighted sagittal and axial imaging planes provided the most complete visualization. In specific cases, T2-weighted examinations were useful in demonstrating likely regions of inflammation bordering infected sinus tracts. MRI demonstrates a wide variety of dysraphic spinal anomalies and effectively screens children for occult spinal dysraphism.     

MRI of the skull

Thirty-four patients with a wide variety of benign and malignant incidental skull findings on routine magnetic resonance (MR) imaging of the brain were reviewed. In most instances detection of the lesions was not difficult. However, recognition of various patterns of skull involvement in different disease processes is important. This is particularly true in differentiating benign from malignant lesions, which may be a critical factor in patient management.     

Proton decay and horizontal symmetry

Proton decay can teach us about the so-called horizontal or family symmetry.     

Families,the invisible axion,and domain walls

We consider models in which the unbroken discrete subgroup of a Peccei-Quinn symmetry may be effectively embedded in the rest of the continuous symmetry group to avoid the formation of domain walls. In this context we may gain insight into the family question. We note that instantons in an unbroken “hypercolor” group might be used to reduce the size of the discrete symmetry or to eliminate it altogether.     

Reaction of 1-Methylindole with Dimethyl-Acetylenedicarboxylate an 2:1 Adduct-Dimethyl α, α-Bis(1-Methylindol-3-YL)-Succinate

The structure of 2:1 adduct of 1-methylindole and dimethyl acetylenedicar-boxylate was elucidated as dimethyl α, α-bis(1-methylindol-3-yl)-succinate. Some of its derivatives were prepared.     

A new cyanogenic glycoside from Sorbaria sorbifolia var. stellipila

A new cyanogenic glycoside, sutherlandin-5-trans-p-coumarate was isolated along with a known cardiosdiospermin-5-(4-hydroxy) benzoate fr the aerial parts of Sorbaria sorbifolia (L.) A. Br. var. stellipila MAX. (Rosaceae). The structure of the new compound was established based on spectral evidence.     

Chip-LC-MS for label-free profiling of human serum

The discovery of biomarkers in easily accessible body fluids such as serum is one of the most challenging topics in proteomics requiring highly efficient separation and detection methodologies. Here, we present the application of a microfluidics-based LC-MS system (chip-LC-MS) to the label-free profiling of immunodepleted, trypsin-digested serum in comparison to conventional capillary LC-MS (cap-LC-MS). Both systems proved to have a repeatability of approximately 20% RSD for peak area, all sample preparation steps included, while repeatability of the LC-MS part by itself was less than 10% RSD for the chip-LC-MS system. Importantly, the chip-LC-MS system had a two times higher resolution in the LC dimension and resulted in a lower average charge state of the tryptic peptide ions generated in the ESI interface when compared to cap-LC-MS while requiring approximately 30 times less (~5 pmol) sample. In order to characterize both systems for their capability to find discriminating peptides in trypsin-digested serum samples, five out of ten individually prepared, identical sera were spiked with horse heart cytochrome c. A comprehensive data processing methodology was applied including 2-D smoothing, resolution reduction, peak picking, time alignment, and matching of the individual peak lists to create an aligned peak matrix amenable for statistical analysis. Statistical analysis by supervised classification and variable selection showed that both LC-MS systems could discriminate the two sample groups. However, the chip-LC-MS system allowed to assign 55% of the overall signal to selected peaks against 32% for the cap-LC-MS system.