Cross-reactive cellular immune response to circumsporozoite proteins of Plasmodium vivax and P. falciparum in malaria-exposed individuals

The present review offers a new look at capillary isoelectric focusing (cIEF) by centering on the most troublesome aspects of the technique, namely: 1) how to modulate the slope of the pH gradient, for increasing resolution (equivalent to pH gradient engineering, as easily available in immobilized pH gradients); and 2) how to keep proteins in solution at (and in the proximity of) the pl value. A simple solution is offered in the first case: addition, to the standard 2-pH-units interval, of separators or spacers, i.e., of amphoteric molecules (either single or in combination) able to locally flatten the pH and increment resolution. Examples of the separation of fetal and glycated hemoglobins are provided. In the second case, a unique solubilization power (while maintaining full protein integrity and enzyme activity) is obtained if class I solubilizers are used. They consist of mixtures of sugars (e.g., sucrose and sorbitol) at ca. 1 M concentration, with zwitterions (up to 1 M) such as the class of nondetergent sulfobetaines, but also taurine and some of the Good's buffers (e.g., CAPS). In these solvents, the protein exists in a state of superhydration and its solubility is greatly augmented. The review ends with an excursus on the use of isoelectric buffers in zone electrophoretic separations. Such isoelectric buffers offer unique advantages: They permit very-high-voltage gradients (up to 1000 V/cm) and thus minimize analysis times (down to a few min in 30-35 cm long capillaries). This results in a marked increase in resolution, due to minimal diffusion-driven peak spreading. Such buffers are finding unique applications for generating peptide maps of tryptic digests of proteins and also in the analysis of oligonucleotides.     

Reduced performance of male and female athletes at 580 m altitude

Patients with craniocervical mandibular (TMD) disorders can present with tinnitus as a primary or secondary complaint. The embryology and functional anatomy of the middle ear, temporomandibular joint, muscles of mastication and associated tendons, ligaments, blood vessels, nerves and lymphatics was found to be helpful in establishing etiologic concepts which relate tinnitus to these temporomandibular disorders. In addition to etiologic concepts, treatment modalities are described. The authors relate their experiences as well as those of others with different patient populations.     

Secondary structure mapping of an RNA ligand that has high affinity for the MetJ repressor protein and interference modification analysis of the protein-RNA complex

The secondary structure of an RNA aptamer, which has a high affinity for the Escherichia coli MetJ repressor protein, has been mapped using ribonucleases and with diethyl pyrocarbonate. The RNA ligand is composed of a stem-loop with a highly structured internal loop. Interference modification showed that the bases within the internal loop, and those directly adjacent to it, are important in the binding of the RNA ligand to MetJ. Most of the terminal stem-loop could be removed with little effect on the binding. Ethylation interference suggests that none of the phosphate groups are absolutely essential for tight binding. The data suggest that the MetJ binding site on the aptamer is distinct from that of the natural DNA target, the 8-base pair Met box.     

Airway neural responses to kinins: tachyphylaxis and role of receptor subtypes

Heparitinase cleaves heparan sulfate, a glycosaminoglycan associated with all nucleated mammalian cells and extracellular matrices. Despite the important physiologic role heparitinase is postulated to play in such processes as tumor metastasis and inflammation, the identity of the enzyme remains a matter of controversy and there is a question of whether heparitinase is CTAP III. We report a 900,000-fold purification of heparitinase from human platelets. A multi-step procedure utilizing chromatography on heparin, DEAE, hydroxyapatite and size exclusion matrices was employed and yielded a single protein as judged by Coomassie staining of protein separated by SDS-PAGE. The purified protein had an apparent molecular mass of 35 kDa by size exclusion chromatography and 55 kDa by SDS-PAGE. During purification, heparitinase activity co-eluted from the hydroxyapatite and size exclusion columns with the 35-55 kDa protein, confirming that the purified protein was indeed heparitinase. The 35-55 kDa protein reacted strongly with concanavalin A, a lectin known to bind to heparitinase, further confirming that the protein was heparitinase. Platelet heparitinase formed dimers and tetramers upon storage in a purified form, possibly accounting for the various molecular weights previously reported for the enzyme. A partial amino acid sequence of the protein revealed that heparitinase has not been previously sequenced.     

Kalirin inhibition of inducible nitric-oxide synthase

Nitric oxide (NO) acts as a neurotransmitter. However, excess NO produced from neuronal NO synthase (nNOS) or inducible NOS (iNOS) during inflammation of the central nervous system can be neurotoxic, disrupting neurotransmitter and hormone production and killing neurons. A screen of a hippocampal cDNA library showed that a unique region of the iNOS protein interacts with Kalirin, previously identified as an interactor with a secretory granule peptide biosynthetic enzyme. Kalirin associates with iNOS in vitro and in vivo and inhibits iNOS activity by preventing the formation of iNOS homodimers. Expression of exogenous Kalirin in pituitary cells dramatically reduces iNOS inhibition of ACTH secretion. Thus Kalirin may play a neuroprotective role during inflammation of the central nervous system by inhibiting iNOS activity.