The future of intensive care: the study of the microcirculation will help to guide our therapies

The goal of hemodynamic resuscitation is to optimize the microcirculation of organs to meet their oxygen and metabolic needs. Clinicians are currently blind to what is happening in the microcirculation of organs, which prevents them from achieving an additional degree of individualization of the hemodynamic resuscitation at tissue level. Indeed, clinicians never know whether optimization of the microcirculation and tissue oxygenation is actually achieved after macrovascular hemodynamic optimization. The challenge for the future is to have noninvasive, easy-to-use equipment that allows reliable assessment and immediate quantitative analysis of the microcirculation at the bedside. There are different methods for assessing the microcirculation at the bedside; all have strengths and challenges. The use of automated analysis and the future possibility of introducing artificial intelligence into analysis software could eliminate observer bias and provide guidance on microvascular-targeted treatment options. In addition, to gain caregiver confidence and support for the need to monitor the microcirculation, it is necessary to demonstrate that incorporating microcirculation analysis into the reasoning guiding hemodynamic resuscitation prevents organ dysfunction and improves the outcome of critically ill patients.

A review of therapeutic attempts to recruit the microcirculation in patients with sepsis

Microcirculatory dysfunction is a pivotal element of the pathogenesis of severe sepsis and septic shock. Technological development, including sidestream darkfield videomicroscopy, now allows for bedside assessment of the microcirculation. A number of clinical studies have established the importance of the microcirculation in sepsis. The objective of this review is to discuss human trials that have assessed interventions aimed at improving microcirculatory flow in patients with sepsis.

Influence of diabetes on endothelial cell response during sepsis

AIMS/HYPOTHESIS

Several endothelial pathways of cell adhesion, coagulation and vascular endothelial growth factor (VEGF) signalling are activated during sepsis. The objective of this analysis was to investigate the influence of diabetes on biomarkers of endothelial cell activation in sepsis.

METHODS

This was a prospective observational cohort study of a convenience sample of adult patients (age ≥ 18 years) for whom infection was clinically suspected and who presented to an urban tertiary care emergency department between February 2005 and November 2008. We investigated the association of diabetes and sepsis with various endothelial activation biomarkers of cell adhesion (E-selectin, vascular cell adhesion molecule 1 [VCAM-1] and intercellular adhesion molecule 1 [ICAM-1]), coagulation (plasminogen activator inhibitor 1 [PAI-1]) and VEGF signalling (soluble fms-like tyrosine kinase-1 [sFLT-1]).

RESULTS

A total of 207 patients (34% with sepsis, 32% with severe sepsis and 34% with septic shock) were studied, including 63 (30%) with diabetes. Compared with patients without diabetes, patients with diabetes had significantly increased E-selectin and sFLT-1 levels overall; this was most pronounced during septic shock in the stratified analysis. Multivariate models including age, sex, sepsis severity and other variables as potential covariates confirmed the association of diabetes with elevated circulating plasma levels of E-selectin (standardised β 0.24, p < 0.001) and sFLT-1 (standardised β 0.19, p < 0.01), but there was no significant association with VCAM-1, ICAM-1 or PAI-1.

CONCLUSIONS/INTERPRETATION

During septic shock, patients with diabetes had higher levels of circulating biomarkers of endothelial cell adhesion (E-selectin) and VEGF signalling (sFLT-1). Future studies should address whether enhanced activation of the endothelium places patients with diabetes at increased risk for the development of sepsis and worsening morbidity and mortality.

[Trends in the spread of pandemic influenza A(H1N1) swl in the Far East in 2009]

The paper describes the trend in the spread of pandemic influenza A(H1N1) swl virus in the Far East, which started in this region 2-3 months later than that in the European part of Russia. By mid-October seasonal epidemic influenza was practically displaced by pandemic one.

The yield of head CT in syncope: a pilot study

Although head CT is often routinely performed in emergency department (ED) patients with syncope, few studies have assessed its value.

OBJECTIVES

To determine the yield of routine head CT in ED patients with syncope and analyse the factors associated with a positive CT.

METHODS

Prospective, observational, cohort study of consecutive patients presenting with syncope to an urban tertiary-care ED (48,000 annual visits).

INCLUSION CRITERIA

age >or=18 and loss of consciousness (LOC). Exclusion criteria included persistent altered mental status, drug-related or post-trauma LOC, seizure or hypoglycaemia. Primary outcome was abnormal head CT including subarachnoid, subdural or parenchymal haemorrhage, infarction, signs of acute stroke and newly diagnosed brain mass.

RESULTS

Of 293 eligible patients, 113 (39%) underwent head CT and comprise the study cohort. Ninety-five patients (84%) were admitted to the hospital. Five patients, 5% (95% CI=0.8%-8%), had an abnormal head CT: 2 subarachnoid haemorrhage, 2 cerebral haemorrhage and 1 stroke. Post hoc examination of patients with an abnormal head CT revealed focal neurologic findings in 2 and a new headache in 1. The remaining 2 patients had no new neurologic findings but physical findings of trauma (head lacerations with periorbital ecchymoses suggestive of orbital fractures). All patients with positive findings on CT were >65 years of age. Of the 108 remaining patients who had head CT, 45 (32%-51%) had signs or symptoms of neurologic disease including headache, trauma above the clavicles or took coumadin. Limiting head CT to this population would potentially reduce scans by 56% (47%-65%). If age >60 were an additional criteria, scans would be reduced by 24% (16%-32%). Of the patients who did not have head CT, none were found to have new neurologic disease during hospitalisation or 30-day follow-up.

CONCLUSIONS

Our data suggest that the derivation of a prospectively derived decision rule has the potential to decrease the routine use of head CT in patients presenting to the ED with syncope.

Early goal-directed therapy: a UK perspective

The surviving sepsis campaign developed guidelines in 2003 that were designed to increase physician awareness of sepsis and to develop a series of recommendations for the management of the patient with sepsis. The guidelines had the support of 11 international professional organisations across a variety of specialties, and advocate aggressive, early goal-oriented resuscitation in appropriate patients.

Absolute lymphocyte count as a predictor of CD4 count

STUDY OBJECTIVE

To determine whether the absolute lymphocyte count (ALC) (white blood count x lymphocyte percentage) can be used to predict a low CD4 count.

METHODS

We conducted a retrospective data analysis of consecutive CD4 count analyses performed between January 1, 1995, through December 1, 1995, at an urban university teaching hospital. Results of consecutive CD4 counts and simultaneously measured ALCs were analyzed from samples obtained in inpatient, clinic, and emergency department settings. The ability of ALC to predict a CD4 count less than 200 cells/mm3 was analyzed by calculating sensitivities, specificities, predictive values, and likelihood ratios for a range of ALC values.

RESULTS

Among the 807 samples, 322 results (40%) had a CD4 count less than 200 cells/mm3. The ALC and CD4 count were correlated (r=.69, P<.0001). An ALC less than 1,000 cells/mm3 predicted CD4 counts less than 200 cells/mm3 with a sensitivity of .67 (95% confidence interval .62 to .72), specificity of .96 (.94 to .98), positive predictive value of .91 (.87 to .95), and a negative predictive value of .81 (.78 to .84). An ALC less than 2,000 cells/mm3 predicted CD4 counts less than 200 cells/mm3 with a sensitivity of .97 (.95 to .99), specificity of .41 (.37 to .45), positive predictive value of .52 (.48 to .56), and negative predictive value of .95 (.92 to .98).

CONCLUSION

A reliable relationship exists between ALC and CD4 count. In a similar population, an ALC less than 1,000 cells/mm3 is predictive of a CD4 count less than 200 cells/mm3, and an ALC greater than or equal to 2,000 cells/mm3 is predictive of a CD4 count greater than or equal to 200 cells/mm3. Physicians may find these criteria useful in identifying patients with increased risk of opportunistic infection.

Reversion to normal phenotype induced by SV40 in a spontaneously transformed malignant Chinese hamster cell line

By using a selection procedure that excluded the transforming effect of SV40, reversions to several properties of normal phenotype were for the first time obtained in a transformed Chinese hamster cell line after SV40 infection. The value of induction to recovery of contact inhibition was typical for SV40-induced reverse gene mutations. Thirteen of 15 isolated revertant clones were T-antigen positive, thus synthesizing the product of viral oncogene. Therefore, in the majority of clones reversion occurred in spite of the presence of viral transforming protein. Dot hybridization revealed the presence of SV40 DNA in all revertants including those expressing no T antigen. The virus rescued from one T-antigen positive and two negative clones proved to be infectious. Reversion to contact inhibition was followed by reversion as regards serum requirements and growth in soft agar. However, in all cases reversion was partial. Karyologic analysis of revertant clones showed that six clones maintained the hypodiploid karyotype of the parental clone, six revertants were near-tetraploid, and one was near triploid. The possible events underlying the SV40-induced reversions to normal phenotype and the role of virus-induced mutations in viral carcinogenesis are discussed.

The action of the tumour promoter, TPA, on mutagenesis induced by different agents (UV light, chemical and viral mutagens)

The present paper deals with effects of 12-O-tetradecanoylphorbol-13-acetate (TPA) on the frequency of induced mutations to 6-mercaptopurine (6MP) and ouabain resistance in Chinese hamster and mouse cells. UV light, bovine adenovirus 3(BAV-3) and 5-bromodeoxyuridine (BrdU) were used as mutagens. TPA was shown to raise the frequency of gene mutations induced by UV light and BAV-3 but it did not enhance the mutagenic effect of BrdU. We also examined the ability of BAV-3 and BrdU to induce tumours in mice. BrdU was shown to have no carcinogenic effect. The results suggest that TPA enhances the mutagenic effect only for carcinogenic mutagens.

[Delayed-type hypersensitivity reaction induced in mice by the administration of an inactivated influenza vaccine]

The conditions of delayed-type hypersensitivity induction following immunization with an inactivated influenza vaccine in BALB/c and CBA/H mice treated with cyclophosphane were studied. The results showed that the delayed-type hypersensitivity reaction had no type specificity when revealing preparation injected to immunized mice is a vaccine prepared with chorioallantoic fluid, but it is specific when a tissue vaccine is used. The use of inactivated influenza viruses cultivated on different cell-types for sensitization and revelation of the hypersensitivity state allowed to evaluate the level of the delayed-type hypersensitivity induced by untreated virus.

[Allergenic action of inactivated influenza vaccines]

The allergenic action of influenza vaccines was evaluated by the determination of the capacity of sera, taken before and after immunization, for inducing the degranulation of rat mast cells in the presence of the vaccine preparation. In this test sera from three groups of volunteers immunized with experimental and commercial batches of influenza inactivated vaccines, purified and concentrated by gradient centrifugation, was studied. The absence of immediate-type allergization after a single administration of the vaccines under study was shown.

[Adsorbed subunit influenza vaccine: its isolation and characteristics]

Experimental batches of adsorbed subunit influenza vaccine were prepared from the envelope of glycoprotein antigens separated from the influenza virion by treatment with a cationic detergent (cetyltrimethylammonium bromide). Purified and concentrated influenza virus strains A(H1N1) and A(H3N2) were obtained by gradient centrifugation; additional purification, with a view to removing ovalbumin and structural components of the chorioallantoic membrane, was achieved by gelfiltration. The composition and biological properties of the vaccine are described.

The oncogene of BAV-3 as a mutagen

We studied the mutagenic and carcinogenic effects on mammalian cells of two EcoRI DNA fragments of bovine adenovirus type3 (BAV-3) integrated into the pBR325 plasmid. Fragment D located between 3.6 and 19.7 map units, contains the viral oncogene, fragment C, located between 44.3 and 63.7 map units, has no oncogenic activity. The BAV-3 oncogene was shown to increase significantly the frequency of 6-mercaptopurine (6MP)-resistant mutants in Chinese hamster calls. Fragment C, pBR325 without viral sequences and DNA from normal Syrian hamster cells did not have any mutagenic effect. We also looked at the combined action of the viral DNA fragments and the tumour promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), which enhances the transforming effect of carcinogens. TPA was shown to increase the mutant yield on exposure to the viral oncogene but not to induce mutagenic activity in those types of DNA that are unable to transform cells. Probably TPA does not affect the initiation of the mutation process, but acts on later stages just as it affects carcinogenic activity. Thus the results obtained confirm the existence of parallelism between the mutagenic and transforming effects of viral DNA and show that both activities are mapped in the same region of viral DNA - its oncogene.

[Immune response of noninbred mice to subvirion influenza vaccines with various antigen and sorbent loads]

The variants of splitted and subunit influenza monovaccines from virus strains A/Leningrad/385/80R (H3N2) and A/Kiev/59/79R (H1N1), adsorbed on aluminium hydroxide and having the varying content of hemogglutinin and the carrier, have been studied. The immune response of noninbred mice to a single and double injections of these vaccines have been evaluated, the concentrations of the antigen and the carrier inducing a high response in the animals, have been determined. Differences in the immunological potency of hemagglutinins H1 and H3 have been noted.

Complementation analysis of locus for hypoxanthine guanine phosphoribosyltransferase in Chinese hamster cells

The study deals with intragenic complementation between clones of Chinese hamster cells carrying mutations in the HPRT gene. All clones were of independent origin, selected in media containing one of three purine bases: 8-azaguanine (8 AG), 6-mercaptopurine (6MP), or 6-thioguanine (6TG). Some of the clones were spontaneous, others were induced by various mutagens. To make the study less time-consuming, an experimental set-up was proposed for simultaneous complementation testing of up to 10 clones. As a result, about 400 combinations of clones have been analyzed. Twelve pairs of complementating mutants have been identified in HAT medium. A linear complementation map has been constructed for the HPRT locus, showing five complementation groups. The changes in kinetic and other characteristics observed for mutant HPRT show that all the mutants studied carry structural gene mutations. Analysis of the biochemical characteristics of HPRT has revealed considerable differences between mutant enzymes in clones belonging to different complementation groups (three groups were examined). At the same time, the four mutant clones of complementation group II show similar HPRT characteristics, suggesting a relative similarity of their structural variants of the enzyme. The hybrid nature of HPRT in clones resulting from the fusion of mutant cells confirms the intragenic nature of complementation.

[Effect of endotoxin on the migration of hematopoietic colony-forming cells and on the repopulation of hematopoietic organs in partially irradiated mice]

In experiments on (CBA X C57BL)F1 hybrids it was shown that the administration of sublethal doses of endotoxin to locally exposed (spleen, 9 Gy) animals enhanced the repopulation of the exposed haemopoietic tissue (spleen and bone marrow). It is concluded that endotoxin has a favourable action on the recovery of haemopoiesis of partially irradiated mice which confirms the idea of the possibility of using stimulators instead of autotransplantation of bone marrow from intact parts.

Mutagenic effects of DNA-containing oncogenic viruses and malignant transformation of mammalian cells

It was discovered in the 1970s that oncogenic viruses could induce gene mutations in mammalian cells. The phenomenon seems to be widespread: it was observed with all groups of DNA-containing viruses and some retroviruses. The mutagenic effects of the tested viruses at gene level are not locus specific. The viruses induce point mutations, including base substitutions, as well as deletions and insertions. The mutagenic effect of SV40 is controlled by the activity of the early A gene, which encodes the T antigen. Presumably, the process of integration creates the possibility for occurrence of mutations early after infection. Mutagenesis seems to be induced by an integrated virus, though to a much smaller extent. Virus-induced mutagenesis may be connected with an activation of the cell error-prone repair systems. The sum total of the experimental data shows that virus-induced mutagenesis and transformation are interrelated: (A) viruses, like other carcinogenes, display mutagenic activity; (B) viruses that are far removed from each other systematically, whose only similarity lay in being oncogenic and capable of integration, simultaneously showed the ability to induce gene mutations; (C) agents changing the rate of transformation also changed the rate of gene mutations: (D) The function of mutagenicity was mapped in the oncogene of SV40 (gene A); and the DNA of (E) mouse mammary carcinoma virus (MMTV) and avian leukosis virus (ALLV) induced tumors has been found to contain nucleotide sequences that transform 3T3NIH cells but do not carry any viral genetic information. Mutagenesis induced by oncogenic viruses may play a part in the multistage process of malignant transformation, though its contribution may be different in various specific cases and for different groups of viruses. Further studies of the uncommon mutagens, which viruses seem to be, may greatly increase our knowledge of the virus-cell relationship. An understanding of the extent of genetic danger inherent in viruses and live viral vaccines is necessary for practical medicine.

[Determination of bacterial endotoxin admixtures in inactivated influenza vaccines]

The materials substantiating the possibility of using the method for the determination of the lethal effect of endotoxin on dactinomycin-treated mice are presented. This determination is made with a view to detecting the admixtures of endotoxins in whole-virion and subvirion inactivated influenza vaccines at different stages of their manufacture, as well as in the final product. The proposed test is highly sensitive, rather simple in its practical realization and can be used for evaluating the degree of the purification of influenza vaccines from endotoxins.

[Genetic nature of one of the traits of malignant cell transformation in vitro]

The genetic events controlling the ability of transformed cells to grow in a medium with a low serum content (ser+) were studied. A hypodiploid clone of Chinese hamster cells with normal serum requirements (49a5ser-) was used as starting material. The results of the fluctuation tests have shown that serum-independence is a random spontaneous event. Its rate of occurrence is 1-2 . 10(-5). The concomitant study of a gene mutation (resistance to 6-mercaptopurine) revealed similar characteristics with respect to the distribution of the number of mutants in replicate cultures and the mutation rate. N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and the oncogenic SV40 virus significantly increased the frequency of ser+ colonies. In the majority of clones isolated in a medium with 1% serum (11 spontaneous and 7 induced by MNNG), the ser+ character proved to be stable after different periods of cultivation without selective pressure. The degree of serum-independence varied in different clones. The results suggest that the ability to grow in a medium with a low serum content originates, in most cases, from a mutation event.

The mutational origin of serum independence in Chinese hamster cells in vitro

The genetic mechanisms determining the ability of transformed cells to grow in a medium with a low serum content (ser+) were studied in a clone of Chinese hamster cells with normal serum requirements. The fluctuation test has shown that serum independence occurs as a random spontaneous event. Its rate of occurrence is about 10(-5). The concomitant study of a gene mutation (resistance to 6-mercaptopurine--6MP) revealed similar characteristics with respect to the distribution of the number of mutants in replicative cultures. N-methyl-N1-nitro-N-nitrosoguanidine (MNNG) and SV40 significantly increased the frequency of ser+ colonies. Induction was detected after an expression time of 3-4 days, which is typical of gene mutations. In 16 out of 18 ser+ clones of independent origin the ser+ character remained stable. The results suggest that the ser+ character originates in most cases from a mutation event.

The role of the transforming A gene of SV40 in the mutagenic activity of the virus

The mutagenic activity of the tsA239 mutant of SV40 which synthetizes a defective T antigen at 40 degrees C was investigated in Chinese hamster cells under permissive and nonpermissive temperature. At 33 degrees C the virus increased the yield of 6-mercaptopurine-resistant colonies after 2 days expression time by a factor of 1.6-4 as compared with the control and raised the frequency of aberrant metaphases after the same time by a factor of 1.9-3.4. In the same experiments, with the same initially infected population of Chinese hamster cells, at 40 degrees C tsA SV40 did not induce either gene mutations or chromosome aberrations at the same early stage after infection. Presumably the activity of the A gene of SV40 is necessary not only for the transforming but also for the mutagenic effect of the virus.

[Immunization with a complex preparation: a new method of influenza prevention. The basis for using a complex preparation for preventing influenza]

A combined preparation for influenza prevention (CPIP) consisting of an interferon inducer stimulating immunogenesis and killed influenza vaccine is proposed. Twenty five inducers-stimulators have been tested: polynucleotides, polysaccharide and lipopolysaccharide extracted from Salmonella typhosa. Intranasal administration of CPIP to laboratory animals markedly stimulates interferon, secretory, and circulating antibody synthesis. Resistance to fatal influenza infection develops within 18 hours after administration of CPIP and its intensity increases in the following 14 days (the observation period.

Oncogenic adenovirus as mutagen for chinese hamster cells in vitro

Oncogenic bovine adenovirus (BAV3) was shown to induce chromosome aberrations and gene mutations to 6-mercaptopurine (6MP) resistance in Chinese hamster cells. BAV3 showed the highest mutagenic effect at the chromosome level 12--24 h postinfection. After 48 h the yield of aberrations dropped to the control level, where it remained after 72 and 96 h. BAV3 showed a highly significant induction of mutations to 6MP resistance 48 h postinfection. The effect of the combined treatment of cells with 5-bromodeoxyuridine (BrdU) and BAV3 on mutagenesis at chromosome and gene levels proved to be synergistic. The mutagenic activity at the gene level of BAV3, along with the earlier established mutagenic effect of SV40, indicates that this property is probably inherent in many DNA-containing oncogenic viruses. The possible mechanisms underlying malignant transformation and mutagenesis are discussed.

[Chinese hamster cells mutant for the hypoxanthine-guanine phosphoribosyltransferase locus. II. Characteristics of the hybrids revealing intragenic complementation]

After polyethylene glycol treatment of GPRT- mutant cells, 12 clones were isolated on the ATG medium showing intragenic complementation. Karyological analysis confirmed the hybrid nature of the clones isolated. The GPRT activity in the hybrid clones, as assessed in vitro, exceeded the sum of parental activities. In vivo incorporation of 14C-hypoxanthine showed the GPRT activity in the hybrids to be an order of magnitude higher than in the mutant parental cells. Moreover, the GPRT activity in the hybrid clones was found to increase considerably during cultivation on the ATG medium; hence, their ability to multiply on this selective medium. All hybrid cells surviving and multiplying on the ATG medium were shown to maintain a high enough resistance to 8-AG, 6-MP and, to somewhat less extent, to 6-TG. The frequency of complementation was determined for the cells of mutant clones selected on media with different purine base analogues. The complementation map for the GPRT locus was constructed and proved to be linear. Five groups of complementation were specified.

[Characteristics of preparations of typhoid antigens obtained by ultrafiltration]

The properties of the preparations of the total typhoid antigens isolated by various methods, purified and concentrated by ultrafiltrations, were studied, and the technique of the preservation of their high solubility on drying (the neutralization and removal of disperse components prior to drying) was developed. Preparations obtained by ultracentrifugation were characterized by lower ash content and, when compared with alcohol tryptic preparations, had better antigenic properties, inducing the synthesis of not only O- and Vi-, but also H-antibodies in high titers.

[Postreplicative DNA repair in UV-sensitive Chinese hamster cell clones]

The postreplication repair (PRR) of DNA has been studied in UV-irradiated (10 J/m2) and carcinogen (7-bromomethylbenz(alpha)anthracene -- BMBA) treated (1.65-3.3) 10(-6) M Chinese hamster clones with different UV-sensitivity. Ultracentrifugation in alkaline sucrose gradients has been used. Compared to the UV-resistent clone V-79, the UV-sensitive clone CHS2 displayed a lower effectivity of PRR of DNA after both UV-irradiation and carcinogen treatment, by 6 and 10 times, resp. Thus, there is a positive correlation between lethal and mutagenic effects of UV-irradiation and the effectivity of PRR of DNA. The same conclusion is apparently true in the case of carcinogen 7-BMBA treated Chinese hamster cells.

The synergistic effects of SV40 and BUdR on induction of gene mutations and chromosomal aberrations in Chinese hamster cells

The induction of chromosomal aberrations and gene mutations was studied in Chinese hamster cells after separate and combined treatment with BUdR and SV40. Separate treatment of cells with BUdR or virus infection increased the yield of chromosomal aberrations and reversions from glutamine requirement, expressed at 40 degrees C (a ts mutant), to prototrophy. The combined effect of the incorporation of BUdR into one DNA strand, and a subsequent infection by SV40 was additive as regards the percentage of aberrant metaphases. The integration of the analogue into both DNA strands followed by SV40 treatment resulted in a statistically significant increase in the frequency of aberration carrying metaphases, as compared with the frequency expected if the two agents had acted additively. The same phenomenon was detected when the frequency of reversions to glutamine independence was studied. Hence, the effect of the joint treatment by BUdR incorporated into both DNA strands and SV40 was synergistic. This is known to characterize the effect of BUdR on virus-induced transformation. Therefore, obviously the agent that enhances the malignant transformation of cells by the virus similarly modifies its mutagenic activity. The results obtained are presumed to confirm the previously advanced hypothesis that the same events following infection might control both the integration of viral DNA into the host-cell chromosome (and hence cell transformation) and virus-induced mutagenesis. The role of repair processes in the synergistic effect of BUdR and SV40 in the yield of reversions to glutamine independence is discussed.

[Stimulation of nonspecific resistance in mice with high- and low-molecular fractions of endotoxin on 2 models of Shigella infection]

The capacity of S. paratyphi B endotoxin and its high molecular (HMF) and low molecular (LMF) fractions to stimulate the resistance of mice to shigella infection in intraperitoneal and intranasal challenge was investigated. The HMF developed high activity after the intraperitoneal injection (efficiency index--EI = 2.8). All the preparations were less active on the lung model (EI = 1.6--1.7). Materials of this work lead to the conclusion that in studying the phenomenon of nonspecific resistance induction conditions providing antitoxic and antiinfectious resistance should be considered separately.

[Study of the structure and function of endotoxins with the aid of enzymes. 2. Modification of Salmonella paratyphi B endotoxin with lysozyme and lipase]

Endotoxin preparations from the S. paratyphi B cultures, isolated by various methods, were treated with lysozyme (splitting of beta-1,4-glycoside links of lipid A) and lipase of the pancreas (splitting of complex ester links of glycerophosphatides). Lysozyme and, to a lesser extent, lipase, were capable of partial depression of the toxic endotoxin function. The process of enzymatic detoxication coursed selectively, without influencing the serological and immunological activity of the preparations. Suppositions are put forward on the complicated nature of the toxic endotoxin function manifestation and possibility of provision of detoxication effect by specific actions differing by the point of application.

[Use of Soviet semipermeable acetate-cellulose membranes for concentration and purification of typhoid antigens]

A study was made of a possibility of using Soviet made membranes "Vladipor" with a pore diameter of 16--17 nm for the purpose of concentration and purification of antigenic extracts from stab cultures of S. typhi obtained by the action of typsin, hydrogen peroxide and detergents. Preparations, complete by antigenic structure, were obtained by ultrafiltration, with a good yield. The maximal rate of ultrafiltration was noted in case of "peroxide" antigenic preparations. The use of diafiltration provided a significant reduction of the ash content in the end products.

[New principles for obtaining protective antigens from deep cutlures of enterobacteria]

A model of S. typhi submerged culture was used; application of the principle of sparing extraction of surface protective antigens by the action of sublethal concentrations of two damaging agents differing by the mechanism of inhibition of the processes of vital activity of the microorganisms was founded. The principle is based on regularities characteristic of cells of bacterial pupulations: a) nonhomogeneity of individual cells of the population by the resistance to the damaging agents, and b) independence of distribution in the population cells of resistance to different damaging agents. The following typhoid antigens were obtained by combined action of sublethal concentrations of hydrogen peroxide (0.25%) and formalin (0.1%): antigens with a full antigenic structure (inducing formation of O-, Vi- and H-antibodies), of low toxicity (V50 - 0.65+/-19 mg) and highly immunogenic (AU50- 0.45+/-0.25 mug) in experiments on mice.

Induction of gene mutations and chromosomal aberrations by simian virus 40 in cultured mammalian cells

Induction of gene mutations by SV40 was studied in aneuploid human and Chinese hamster cells. In Chinese hamster cells SV40-induced chromosome aberrations were also studied. SV40 penetrated into the cells of both lines and induced synthesis of the T antigen. The efficiency of infection in Chinese hamster cells was tested additionally by their ability to form colonies in medium lacking the serum growth factor. The maximal number of cells with serum growth factor independence was observed on the first day after infection. When hamster cells had been maintained in "factor-free medium" for the first two passages after infection a sub-line was isolated, which synthesized T antigen 60 days after exposure to SV40. This was considered to be an indirect proof of the integration of viral genome into host chromosome. A significant increase in the frequency of chromosomal aberrations was detected in SV40-infected Chinese hamster cells. It was observed on the first and second days after treatment. The most numberous were the chromosome and chromatid breaks, which were distributed randomly in 5 morphological groups according to the chromosome length. SV40-induced mutations of resistance to 8-AG and 6-MP in human and Chinese hamster cells respectively were detected, when cells were plated in selective medium one to five days after infection. Induction was detected in all the 4 experiments with human cells and in 9 out of 11 experiments with Chinese hamster cells. Induction was highly significant according to the Wilcoxon test (P greater than 0.99), when the results of all experiments carried out in human and Chinese hamster cells were summarized. Resistance was stable after prolonged cultivation of 13 isolated clones under non-selective conditions. It is suggested that viral genome integration, gene mutations and chromosomal aberrations may have common molecular mechanisms. The role of gene mutations in virus-induced carcinogenesis is discussed.

[Characteristics of the hydrodynamic and biological properties of flagellar preparations isolated from submerged cultures of S. typhi]

A study was made of the hydrodynamic and biological properties of the flagella from the S. typhi 4446 cultures, isolated by the methods of differential centrifugation, in crude condition and following depolimerization and denaturing by the action of chemical and physical agents. Molecular parameters of the slow and rapid components of the flagella and subunits of the flagellin were compared. The greatest antigenic activity was possessed by the high molecular fraction of the flagella isolated in the 60% sucrose density gradient.

[Construction of new types of chemical vaccines for the prevention of intestinal infections, and their qualitative assessment. IV. Physical properties and immunological characteristics of the experimental series of chemical vaccines presented for comparative study]

The authors present the results of study of physico-chemical properties of the chemical sorbed monovaccines from the antigens of the causative agents of typhoid fever, paratyphoid A and B and Sonne and Flexner dysentery obtained by various methods; the results of investigation of their reactogenic properties and immunological activity of limited groups of volunteers also given. The vaccines from the antigens obtained by sparing methods were less reactogenic than the rest experimental and control vaccines obtained from the tryptic antigens. The majority of the experimental vaccines caused a significant increase of the specific antibody titres in the sera of the vaccinated persons: typhoid vaccines--of the O-, VI- and H-antibodies, paratyphoid B vaccines--of the O- and H-antibodies; the control vaccines from the tryptic antigens failed to induce the H-antibody synteisis in the vaccinated persons. Experimental dysentery monovaccines induced a greater increase in the antibody titres than the control vaccines.