Oxidative stress and thioredoxin system

Oxidative stress plays an important role in the modulation of several important physiological functions. On the other side, oxidative stress is accountable for development of many unphysiological changes, which can be deleterious for cells. Consequently, at the present time there is increased interest about study mechanisms and changes evocated by oxidative stress. Despite the highly oxidizing environment (21% oxygen, at sea level), at normal conditions, the cell cytoplasm of all aerobic organisms is reduced and proteins contain free sulfhydryl groups. In the cytoplasm, two major systems were identificated responsible for maintaining a reduced state: thioredoxin and glutathione/glutaredoxin system. Thioredoxin in bacteria, thanks to the low redox potential is the major dithiol reductant in the cytosol, or an advanced equivalent to dithiothreitol of cells (Holmgren 1985). Thioredoxin system acts the dominant role in many physiological processes (see below) and it is also a cell antioxidant.

Pseudomonas aeruginosa phage lysate as an immunobiological agent. 1. Selection of Pseudomonas aeruginosa clinical strains for phage lysate preparation

A total of 2087 Pseudomonas aeruginosa isolates collected during the period 1994-1997 were used as starting material. Out of 1704 in-patient isolates, 299 strains were selected for the preparation of phage lysates but only five strains provided stable lysates, i.e., maintained the ability to be repeatedly and completely lysed by the appropriate phage in the course of several years. A set of 193 out-patients (189) and water sources (4) isolates failed to yield strains suitable for phage lysate preparation; 190 strains isolated abroad from patients with cystic fibrosis or respiratory infections included three isolates which, despite having a high degree of mucus production, were suitable for lysate preparation. The antigenic pattern of the phage lysates was ascertained by SDS-polyacrylamide gel electrophoresis.

Epidemiological analysis of Pseudomonas aeruginosa strains isolated from a selected patient population in Brno, Czech Republic

In the 1996/97 period, 1,413 Pseudomonas aeruginosa (PA) strains were isolated from 843 patients of the Brno teaching hospitals of St. Anne and Bohunice together with small groups from other hospitals. In the same period, 203 PA strains, used as controls, were isolated from 187 patients treated outside hospitals. Statistical evaluation was based on 1,023 hospital isolates and 189 control strains. A total of 16 isolates were recovered from the hospital environments and two from therapeutic swimming pools. The epidemiological analysis of these PA strains was based on pyocin typing, serological typing and phage typing. The most frequently occurring pyocin types amongst our strains fell into 8 pyocin-type groups. The prevailing groups differed significantly between the hospital patient and control groups. Similarly, serological typing identified differences in the predominant serotypes between hospital and control patients. The phage typing method revealed that the control PA strains were significantly more sensitive to 21 polyvalent bacteriophages used than the hospital isolates. In relation to pyocin and serological typing, strains isolated from the hospital environment showed characteristics similar to those of the PA strains isolated from hospital patients. Our results indicate that the majority of strain isolated from hospitalised patients had their origin from human or inanimate contacts in the hospitals.

[Structural correlations in splenic tissue in idiopathic thrombocytopenic purpura in adults]

Immunologic activation of the splenic white pulp seemed to be an important feature of the structural changes in the 8 splenectomized patients with ITP. However, destruction of the platelets with CD 16+ monocytes was the most prominent change in the Billroth's cords of the splenic red pulp. Classical NK cells did not play an important role in platelets destruction.

[Immunohistochemical detection of cytokine receptors on cryostat tissue sections]

We have studied tissue expression of the cytokine receptors using a high sensitivity biotin-streptavidin system on cryostat sections. We used a panel of monoclonal antibodies from the 6th International Workshop on Human Leukocyte Differentiation Antigens, namely CD25 (IL-2R alpha), CD95 (FAS antigen), CD116 (GM CSFR), CD117 (SCFR), CD120 alpha (TNFR I), CD120b (TNFR II), CD121a (IL-1R I), CDw123 (IL-3R), CD124 (IL-4R), CD126 (IL-6R), CD127 (IL-7R), CDw128 (IL-8R), CD130 (gpl130), CD131 (IL-3R), CD132 (IL-2R gamma), CD134 (OC-40), CD135 (FLT3/FLK2). Examined tissues (lymph nodes and spleens) were obtained from 12 patients with folicular non-Hodgkin's lymphoma, periferal T non-Hodgkin's lymphoma, B lymphoma, myeloma, Hodgkin's disease, two cases of T cell rich B-lymphoma, autoimmune haemolytic anemia and two cases of rudimentary trombocytopenic purpura. Our results indicate that immunohistological technology using native tissues on cryostat sections, monoclonal antibodies and the visualisation with biotin-streptavidin is a particularly suitable supplementary staining procedure for detection of the cytokine receptors in tissues.

A new bacteriophage typing scheme for Proteus mirabilis and Proteus vulgaris strains. 3. Analysis of lytic properties

The lytic properties of 21 bacteriophages constituting a new typing set for Proteus were examined in 507 Proteus mirabilis and 29 P. vulgaris strains isolated from patients and healthy subjects. Comparison of their morphological, serological, genetic and lytic properties showed that, in the Myoviridae and Podoviridae families, some phages were so closely related that the presence of all of them in the set was redundant. Analysis of the lytic properties revealed that some of the bacteriophages were not active enough to facilitate the differentiation of Proteus strains. The size of the final typing set was reduced from 21 to 12 phages but it was suggested that, in order to improve the differentiation capacity of the set, new phages should be included.

[Comparison of proliferative activity in malignant lymphomas determined by immunohistologic methods with various antibodies]

Proliferation Index (PI) was evaluated in a group of 48 malignant lymphomas. Comparison of 3 antibodies showed that DAKO-EPOS Anti-PCNA/HRP and MIB-1 (Immunotech) suite to routine PI evaluation. Low figures of PI were obtained when using DAKO-EPOS Anti-Ki-67/HRP which did not even discriminate between prognostic groups of malignant lymphomas.

Differentiation of Proteus mirabilis and Proteus vulgaris strains by means of proticine typing: a longitudinal epidemiological study

In the years 1979, 1980, 1982-83, 1986-87 and 1992-93, 673 strains of P. mirabilis and 25 strains of P. vulgaris were isolated from the urinary tracts of patients at a Teaching Hospital in Brno. In 1982-83 and 1992-93, strains of P. mirabilis and P. vulgaris were isolated from the urine and faeces of two groups of Brno population and used as controls. Using the P/S typing method, 94.7% of hospital isolates and 85.5% of control strains could be differentiated by their types. The strains that could not be typed (8.2%) were classified as PO/SO or N types; in the remaining strains, 182 various P/S types could be distinguished. The strains that could not be typed occurred more frequently in control groups (48 out of 337) than in hospital isolates (37 out of 698). Over the whole period, P5/S6, S7, S9 and P1/S2, S11 were the prevailing P/S types of hospital isolates and were placed, together with related types, in groups P5 and P1, respectively. In 1982-83, a significant shift (p < 0.01) from the initially prevailing P5/S6, S7, S9 type to the P1/S2, S11 type of P. mirabilis was recorded. Approximately one third of the hospital isolates in all the periods examined was found to be sporadic, with the exception of 1992-93 when the sporadic strains doubled in frequency (p < 0.01). In control strains, the frequency of sporadic types was twice that of the hospital isolates (p < 0.01) in 1982-83 and, 1992-93, it was equal to the frequency of hospital isolates. This implied a fall in the presence of hospital-acquired strains in the last period of study.

Nosocomial infections caused by selected gram-negative bacteria at the Anaesthesiology and Intensive Care Unit of the Teaching Hospital in Brno

In the course of 13 months we monitored the occurrence of strains of P. mirabilis, P. vulgaris, Kl. pneumoniae, including its indole-positive variant and S. marcescens in patients of the Anaesthesiology and Intensive Care Unit (AICU) of the Teaching Hospital (TH) in Brno. Out of 436 patients hospitalized at that time, 95 (21.8%) were colonized or infected by one or all of the bacterial species studied. Out of those 95 patients, 48 (50.5%) came to the AICU already colonized or infected by one of the studied agents mostly from other wards of the TH or from other hospitals. At the AICU, 32 of them were reinfected or superinfected by one, two or all of the bacterial species studied. Of the 436 hospitalized patients, 79 (18.1%) were newly infected, reinfected or superinfected. By serotyping, proticine production and proticine sensitivity (P-S) typing and phage typing we demonstrated the endemization of some P-S types and phage types of the bacterial species studied and their spreading among the contemporaneously hospitalized patients. The endemic strains of P. mirabilis included P-S types P5/S6, S7, S9 and P5/S6, S7; P0/S9; P1/S2, S11 and P1/S11. The two biotypes of Klebsiella, i.e. K. pneumoniae and K. oxytoca, were identically sensitive to some of the phages 1, 2, 3, 8 and 106, particularly to phages 2 and 3, or 2, 3 and 106. The isolated strains of Serratia were absolutely resistant to the 26 bacteriophages used.

A new phage typing scheme for Proteus mirabilis and Proteus vulgaris strains. 1. Morphological analysis

A new bacteriophage typing set, composed of 22 phages, was established as a tool for differentiation of Proteus strains. All the phages were tailed and included 4 morphological types (A1, A2, B1 and C1). They were classified into the families Myoviridae, Siphoviridae and Podoviridae. From the set, 19 phages had double-stranded DNA and 3 were single-stranded DNA phages.

[Preparation of bone marrow obtained by trephination biopsy]

Easy paraffine technique in processing of bone marrow samples is convenient for structural evaluation and for immunohistology as well. A short fixation in 10% formalin will do, especially when combined with decalcination in Chelaton III. Preparation of sections, staining and immunohistology are analogous to other tissues. Nevertheless, it would be better try to dilute antibodies higher than is usually recommended even if a longer incubation were needed. Intensity of staining can be increased by performing lead sulphocyanate treatment in a microwave oven.

[Methodologic aspects of immunoperoxidase technics]

In attempt to standardize immunoperoxidase tests many partial methodological experiments were performed and the results discussed. The proved processing included purification of peroxidase conjugates, sequential administering in double indirect immunoperoxidase method (double sandwich). A high level dilution of primary antibodies and lengthening of incubation were recommended. Silicagel and vaseline rim round sections were found advantageous for improving adhesion of paraffin sections.

Host-tumor relationship XXXIII. Inhibitor of hyaluronidase in blood serum of cancer patients

Inhibiting activity of blood serum was determined from the decrease of N-acetyl-hexosamine end groups of hyaluronic acid products released by testicular hyaluronidase. Maximum inhibition was observed within the region of pH from 6.5 to 6.8. Correlation between the serum concentration and its inhibiting effect on hyaluronidase was found within the range of the final dilution of serum (in the reaction mixture) from 9 to 45 X. Blood sera of cancer patients showed statistically significant increase of hyaluronidase inhibitor as compared with that of health people.