An essential saccharide binding domain for the mAb 2C7 established for Neisseria gonorrhoeae LOS by ES-MS and MSn

A study of bacterial surface oligosaccharides were investigated among different strains of Neisseria gonorrhoeae to correlate structural features essential for binding to the MAb 2C7. This epitope is widely expressed and conserved in gonococcal isolates, characteristics essential to an effective candidate vaccine antigen. Sample lipooligosaccharides (LOS), was prepared by a modification of the hot phenol-water method from which de-O-acetylated LOS and oligosaccharide (OS) components were analyzed by ES-MS-CID-MS and ES-MSnin a triple quadrupole and an ion trap mass spectrometer, respectively. Previously documented natural heterogeneity was apparent from both LOS and OS preparations which was admixed with fragments induced by hydrazine and mild acid treatment. Natural heterogeneity was limited to phosphorylation and antenni extensions to the alpha-chain. Mild acid hydrolysis to release OS also hydrolyzed the beta(1-->6) glycosidic linkage of lipid A. OS structures were determined by collisional and resonance excitation combined with MS and multistep MSn which provided sequence information from both neutral loss, and nonreducing terminal fragments. A comparison of OS structures, with earlier knowledge of MAb binding, enzyme treatment, and partial acid hydrolysis indicates a generic overlapping domain for 2C7 binding. Reoccurring structural features include a Hepalpha(1-->3)Hepbeta(1-->5)KDO trisaccharide core branched on the nonreducing terminus (Hep-2) with an alpha(1-->2) linked GlcNAc (gamma-chain), and an alpha-linked lactose (beta-chain) residue. From the central heptose (Hep-1), a beta(1-->4) linked lactose (alpha-chain), moiety is required although extensions to this residue appear unnecessary.      

Distribution of HLA antigens in patients with meningococcal infection at different times of year

The character of the distribution of the antigens of the HLA system at different seasons has been studied in 160 patients with generalized forms of meningococcal infection. The occurrence of HLA-Bw16 (the marker of the population gene of susceptibility to meningococcal infection) has proved to be inversely correlated with the seasonal morbidity level.     

Current x-ray studies in the diagnosis of colorectal metastases to the liver

Computed tomography was made in 90 patients to reveal the specific features of images of hepatic metastatic foci of colorectal cancer of various sites. All the patients were divided into three groups. Group 1 included patients with rectal cancer; Group 2 comprised patients with sigmoid cancer, and Group 3 consisted of those with transverse colon cancer. The study was performed in native, arterial, and venous, and delayed phases. The number of foci, their localization, sizes, and shape were analyzed. In addition, the density of a focus, its homogeneity, the presence of a cancer rim, inclusion of calcium salts, and outline sharpness were determined. Computed tomography revealed no substantial differences in the image of foci of hepatic metastases from rectal, sigmoid, and transverse colon cancers.     

Is antiviral therapy in gastroduodenal pathology necessary?

Mucous membrane of the gastroduodenal region of 104 patients with different pathologies (gastritis and erosive ulcerative alterations) was investigated by polymerase chain reaction (PCR). Examination of the biopsy material revealed frequent occurrence of pathogenic strains of Helicobacter pylori (up to 80%) and Herpesviridae (EBV, HHV 6, HHV 7, HHV 8) in various combinations. In such cases it is necessary to use adequate antibacterial and antiviral therapy with individual choice of immunomodulators.     

Effect of self-association on the structural organization of partially folded proteins: inactivated actin

The propensity to associate or aggregate is one of the characteristic properties of many nonnative proteins. The aggregation of proteins is responsible for a number of human diseases and is a significant problem in biotechnology. Despite this, little is currently known about the effect of self-association on the structural properties and conformational stability of partially folded protein molecules. G-actin is shown to form equilibrium unfolding intermediate in the vicinity of 1.5 M guanidinium chloride (GdmCl). Refolding from the GdmCl unfolded state is terminated at the stage of formation of the same intermediate state. An analogous form, known as inactivated actin, can be obtained by heat treatment, or at moderate urea concentration, or by the release of Ca(2+). In all cases actin forms specific associates comprising partially folded protein molecules. The structural properties and conformational stability of inactivated actin were studied over a wide range of protein concentrations, and it was established that the process of self-association is rather specific. We have also shown that inactivated actin, being denatured, is characterized by a relatively rigid microenvironment of aromatic residues and exhibits a considerable limitation in the internal mobility of tryptophans. This means that specific self-association can play an important structure-forming role for the partially folded protein molecules.     

The phenomenon of HLA antigen modification in meningococcal infection

212 patients with the generalized forms of meningococcal infection have been examined. The intensity and quality of lymphocytotoxic reaction in the acute phase and the convalescence period of the disease have been analyzed and the blank calculation has been made at different clinical forms of meningococcal infection. The formation of modified tissue antigens at the acute stage of the disease in the presence of intoxication is shown and the probable role of the intensity of bacteremia in this formation is discussed.