Specificity of antibodies to diphtheria toxin subunits in children with various forms of diphtheria infections

In order to study the specificity of serum antibodies to separate subunits of diphtheria toxin, SDS-electrophoresis of diphtheria toxin preliminary disintegrated on the subunits via trypsin treatment was performed, followed by immunoblotting assay. 86 blood serum samples of children with diphtheria carriers of toxigenic and non-toxigenic strains of Corynebacterium diphtheriae as well as children with other infectious diseases similar to diphtheria in their clinical manifestation, and healthy ones immunized with DTP-vaccine were tested. A special computer program was written and applied for results processing and assumption. The data obtained showed that there were particular differences in frequency of predominating the antibodies to one or another subunit of diphtheria toxin among various groups of the children. We consider that the different specificity of antibodies of sick children and children-carriers is capable to predetermine the different course of infectious process.     

Effect of tetanic anatoxin and carbonic acid level in blood on biosynthesis of antibodies in rats

The paper deals with dynamics of antibody formation in rats. Tetanic anatoxin independently of doses and methods of administration manifests weak immunogenic properties. A complete Freind adjuvant stimulates considerably the biosynthesis of antitetanic antibodies in the primary and secondary immune responses. Electrophoresis of tetanic anatoxin polyacrylamide gel permits isolating two protein fractions, one of them migrates in the immunoglobulin G zone and its mass constitutes 73%, the other-more low-molecular and contains 27% of protein. Dynamics of the acid-base blood state indices and of antibody biosynthesis is studied on models of chronic compensated alkalosis and metabolic acidosis in rats. It is established that during the experiment, simultaneously with an insignificant increase in the total carbonic acid concentration blood, there occurs a 25-60% increase in the titres of antitetanic antibodies as compared to the control. In rats with acidosis there occurs a simultaneously decrease in the intensity of antibody biosynthesis as compared to the control (43-54%) and in the total CO2 content in blood.     

Ultrastructure of human blood T-lymphocytes marked with monoclonal antibodies

The ultrastructure of different human blood T-lymphocyte subpopulations was studied by immunoelectron microscopy using "Orthoclone" monoclonal antibodies (OKT-3, OKT-4 and OKT-8) and peroxidase-antiperoxidase (PAP) complex. It was shown that T-lymphocyte subpopulations, distinct in their surface markers and function, possessed some specific features of submicroscopic structure. OKT-4+ cells (helper/inductor) were characterized by small size, high nucleus/cytoplasm ratio and few cytoplasmic organelles. OKT-8+ cells (suppressor/killer) were larger, had low nucleus/cytoplasm ratio and bean-like nucleus, with their cytoplasm containing numerous mitochondria, well-developed Golgi complex and osmiophilic granules.     

Effect of diphosphonic acids on alkaline phosphatase activity

Kinetics was studied for the alkaline phosphatase activity inhibition by diphosphonic acids. When the ratio of Mg2+ and substrate (S) concentrations [( Mg2+]/[S]) is equal to 10, the process constants for methylene diphosphonic, amino methylene diphosphonic and hydroxyethylidene diphosphonic acids are 0.14, 0.12 and 0.35 mM, respectively. The inhibition is of competitive character. An increase in the Mg2+ concentration to the [Mg2+]/[S] = 40 ratio lowers the inhibition degree for all three diphosphonates; it follows a mixed mechanism. Thus, the inhibition of the alkaline phosphatase activity by diphosphonic acids is due to both competition of the inhibitor for the enzyme active centre and a decrease in the Mg2+ concentration, the phosphatase activator, because of Mg2+ complexing with diphosphonates.     

Study of albumin immobilization on synthetic activated charcoal

The principles of physical and chemical immobilization of 14C-albumin on synthetic carbon sorbents with different physiochemical characteristics and structures are studied with radioisotopic technique. The protein binding to the matrix is shown to occur more tightly in the presence of the activating agent (water soluble carbodiimide). It is marked that the geometric correlation of the protein molecular size and sorbents mezopores dimensions is critical for the effective immobilization. The synthetic spherogranulated CKH carbons are shown to be preferential for biospecific carbon sorbents creation.     

Lipids and carotid plaque in the Northern Manhattan Study (NOMAS)

Background

Heterogeneity in B-type natriuretic peptide (BNP) levels, especially among individuals with acute heart failure with normal left ventricular ejection fraction (HFNEF), can cause confusion in interpreting results. We investigated the characteristics of cases of acute HFNEF with only modestly elevated BNP.

Methods

One hundred forty-two patients with acute or acute exacerbation of chronic HFNEF were divided into two groups by BNP level: BNP < 100 pg/ml (NB group, n = 45) and BNP ≥ 100 pg/ml (B group, n = 97). We compared clinical findings, echocardiography results, and neurohormonal factors between these two groups.

Results

In the NB group, a history of open-heart surgery (OHS) was more frequent (71% vs. 22%, p < 0.0001) and hypertension was less frequent (p = 0.0005). Left atrial diameter (LAd) was higher (p = 0.0026), while interventricular septal thickness, posterior wall thickness, relative wall thickness, left ventricular mass index were lower (p = 0.0005, p = 0.0225, p = 0.0114, p = 0.0051, respectively) in the NB group. In patients with HFNEF, a history of OHS remained an independent predictor of BNP level (< 100 pg/ml) after adjustment for hypertension, age, LAd, and interventricular septal thickness (odds ratio 3.6, p = 0.0252).

Conclusion

We found associations between acute HFNEF with less elevated BNP and a history of OHS. In a patient suspected of HFNEF, a history of OHS is considered diagnostic evidence of presence of diastolic heart failure when plasma levels of BNP are less elevated.     

The number and ultrastructure of CD4+ lymphocytes in the blood of healthy persons and in patients with type 1 diabetes mellitus

The flowing cytofluorometric and electron microscopic methods have been used to study the content and ultrastructure of blood CD4 lymphocytes in healthy and type I diabetic patients. Analysis of submicroscopic structure of the lymphocytes expressing CD4 antigen has revealed its morphological heterogeneity. It has permitted distinguishing four groups of cells. A decrease of the content of CD4+ lymphocytes at the expense of the first group cells and relative increase in the number of the fourth-group cells are observed in the majority of diabetic patients. The availability of parallel-tubular structures in granules forming clusters and first-group lymphocytes, an increase in the number and size of granules of the fourth-group are the most typical changes of ultrastructural characteristics.     

Effect of diphtheria toxin on the viability of phagocytes and B-lymphocytes in animals sensitive and insensitive to it

It is well known, that mechanism of diphtheria toxin (DT) action triggers only if toxin penetrates into acid endosome after binding with specific receptor--heparin-binding epidermal grows factor like grows factor (HB-EGF) on the cell surface. We have suggested that DT is capable to penetrate either into B-lymphocytes, which have specific immunoglobulin receptors for DT or into phagocytes, which are able to phagocytosis of DT, because in both of these cases toxin get in endosome with conditions suitable for its activation. To check this hypothesis the comparative studies with insensitive to DT mice lacking specific receptor for DT, and with sensitive to DT guinea pigs were performed. Influence of DT on vitality of phagocytes and B-cells with different specificity from mice and guinea pigs was studied. B-cells were obtained from animals immunized by control antigen--ovalbumine and recombinant diphtheria toxoid--DT without N-terminal 28 aminoacid residues responsible for toxic effect. The results obtained have showed that DT can penetrate into phagocytes and B-cells specific to DT and kill these cells even if they lack classic receptor for DT. This fact evidences that DT is potentially able to inhibit self-directed antibody response and keep from participation of phagocytes in the protection of organism from infection.