LPS-squalene interaction on d-galactose intestinal absorption

Journal of Physiology and Biochemistry - The dynamic and complex interactions between enteric pathogens and the intestinal epithelium often lead to disturbances in the intestinal barrier, altered...     

Microbiocenosis of the large intestine in acute complicated pneumonia in children

Fifty-six children of early age with pneumonia developed on the background of frequent respiratory infections were placed under observation. In 91.1% of these cases microecological disturbances in the intestine were detected, 46.6% of the patients having third-degree dysbacteriolysis. In such cases it is more correct to regard the "intestinal" syndrome as the clinical manifestation of disturbances in the biocenosis of the intestine, the state of its microflora. Intestinal dysbacteriosis aggravates the course of acute aggravated pneumonia in children and requires the inclusion of special therapy aimed at normalizing intestinal microflora.     

Participation of conditionally pathogenic enterobacteria in the processes of intestinal dysbacteriosis

The presence of a number of conditioned-pathogenic enterobacteria (Klebsiella, Citrobacter, Enterobacter) in patients with intestinal dysbacteriosis, and also their detection in derangement of normal intestinal biocenosis in patients with chronic intestinal disturbances with clinical manifestations of this condition, even in the absence of known bacteriological indications of dysbacteriosis was revealed. Results of investigations led the authors to the conclusion on the participation of a number of conditioned pathogenic enterobacteria in intestinal dysbacteriosis, and permit a suggestion on the necessity of proper assessment of the fact of presence of these bacteria as a possible dysbacteriosis indication.     

Correction of intestinal microflora in chemotherapeutic dysbacteriosis using bifidobacterial and lactobacterial autologous strains

The oral administration of kanamycin (40 mg/kg) or ampiox (500 mg/kg) to guinea pigs for 5 days led to disturbances in their normal intestinal microflora, manifested by a sharp decrease in the levels of lactobacteria and bifidobacteria, as well as by the appearance of large amounts of enterobacteria and enterococci, normally not detected in the proximal and distal sections of the intestinal tract. In adult volunteers receiving kanamycin orally in a dose of 40 mg/kg for 5 days disturbances in microbiocenosis also occurred: the amount of enterococci, staphylococci, lactobacteria and bifidobacteria considerably decreased, enterobacteria becoming the dominating microorganisms. Three oral administrations of bifidobacterial and lactobacterial autostrains immediately after the abolition of the antibiotic facilitated the rapid and effective restoration of the intestinal microflora.     

Microflora of the large intestine in patients with connective tissue dysplasia

The specific features of intestinal aerobic and anaerobic intestinal microflora in children with nondifferentiated connective tissue dysplasia were under study. A high rate of dysbiotic disturbances was noted in patients with connective tissue dysplasia in comparison with healthy persons. Profound quantitative and qualitative changes in the biocenosis of the intestine were detected in patients with the pathology of the gastrointestinal tract as well as that of the locomotor system. Changes in the species composition and the persistence properties of the intestinal microflora may serve as pathogenetic factors in the development of connective tissue dysplasia.     

Correction of immunity disorders, treatment of intestinal infections and disbiosis in children (clinical review)

Acute viral and bacterial intestinal infections in children provoke the Tn2 immune response, resulting in development of severe and complicated forms of the disease and sustained by the disbiotic disturbances due to unnecessarily prolonged use of antibacterial drugs. Cycloferon, an early inductor of interferon-1 and -2, was shown to be safe and efficient in the complex therapy of the intestinal infections. It promoted generation of the Th2 immune response and decrease of the repeated isolation of the pathogen with normalization of the disease clinical signs. The host intestinal microflora was normalized and the level of the opportunistic organisms decreased.     

Free Radicals Scavengers Attenuate Platelet-Activating Factor (PAF)-And Endotoxin-Induced Intestinal Myoelectric Disturbances in Rats

Pretreatment with radical scavengers significantly reduced the intestinal myoelectric disturbances following either E. coli endotoxin or platelet-activating factor (PAF) injection in the rat indicating that free radicals might be involved in the intestinal motor alterations observed in endotoxin shock and that PAF acts partially via free radical production. Moreover, dimethylsulfoxide (DMSO) was found to be more effective in inhibiting the endoxotin-induced intestinal motor alterations, than superoxide dismutase (SOD) and allopurinol. BN 52021, a specific PAF antagonist, was able to reduce the effects of endotoxin on intestinal motility, However, when BN 52021 was combined with free radical scavengers, no additive effect was observed. It is concluded that free radicals involved in endotoxin-induced intestinal motility alterations are at least in part produced in response to PAF.     

The effect of fermented-milk bifidumbacterin on the intestinal microflora of test pilots]

Bacteriological study of intestinal microflora in test pilots, regularly exposed to excessive physical, as well as nervous and emotional strain, has revealed changes in the composition of their intestinal microflora. Correction of microflora by means of bifidumbacterin, a curative lactic fermentation alimentary product, was carried out. Rapid and effective restoration of intestinal microflora and improvement of the general state of patients were noted, which made it possible to recommend this product as a prophylactic remedy for subjects at risk of development of dysbiotic disturbances.     

The use of biological preparations for correction of microbial status in pregnant women

15 pregnant women with pregnancy lasting 28-32 weeks, whose medico-laboratory data (the positive result of the amino test, high pH value and the detection of "key" cells) suggested the presence of bacterial vaginosis, were placed under observation. The bacteriological study of vaginal microflora in all these women revealed pronounced disturbances simultaneously with the development of intestinal dysbacteriosis. The local application of the bacterial preparation "Zhlemik" containing freeze-dried live lactic acid bacteria of vaginal origin and the oral administration of lactic acid bifidumbacterin containing live bifidobacteria of intestinal origin permitted the successful restoration of vaginal and intestinal microbiocenosis. The capacity of biotherapeutic preparations for inducing non-specific immunostimulation led to a significant rise in the levels of IgA, IgM and IgG in vaginal secretions.     

Immunoregulation of the population of intestinal gram-negative microflora

The authors present summarized data obtained in their studies on the presence of close feedback relationship between the state of immunity to common antigenic determinants of lipopolysaccharides (LPS), localized on the cell-wall surface of Gram-negative bacteria, and the development of intestinal dysbacteriosis. The problems dealing with the regulation of the amount of intestinal microflora with immunity factors taking part in the mechanism of such regulation are discussed and analyzed. The state of immunity to common antigenic determinants of LPS of Gram-negative bacteria re-flects, seemingly, the total resistance level of the body, i.e. the functional state of the immune system as a whole. The suggestion has been made that the development of intestinal dysbacteriosis may be basically caused by functional disturbances of the immune system, induced by different exogenous and endogenous damaging factors.     

The host selects mucosal and luminal associations of coevolved gut microorganisms: a novel concept

Along the human gastrointestinal tract, microorganisms are confronted with multiple barriers. Besides selective physical conditions, the epithelium is regularly replaced and covered with a protective mucus layer trapping immune molecules. Recent insights into host defense strategies show that the host selects the intestinal microbiota, particularly the mucosa-associated microbial community. In this context, humans coevolved with thousands of intestinal microbial species that have adapted to provide host benefits, while avoiding pathogenic behavior that might destabilize their host interaction. While mucosal microorganisms would be crucial for immunological priming, luminal microorganisms would be important for nutrient digestion. Further, we propose that the intestinal microorganisms also coevolved with each other, leading to coherently organized, resilient microbial associations. During disturbances, functionally redundant members become more abundant and are crucial for preserving community functionality. The outside of the mucus layer, where host defense molecules are more diluted, could serve as an environment where microorganisms are protected from disturbances in the lumen and from where they can recolonize the lumen after perturbations. This might explain the remarkable temporal stability of microbial communities. Finally, commensals that become renegade or a decreased exposure to essential coevolved microorganisms may cause particular health problems such as inflammatory bowel diseases, obesity or allergies.     

Mechanism of circulatory disorders in animals irradiated at high doses

Some data are reported on pathoanatomical changes, a status of the microcirculatory channel and the coagulogram of animals affected by high doses of ionizing radiation. The signs of disseminated intravascular blood coagulation have been revealed. The authors discuss the relationship between clinical manifestations with coagulopathy development and circulatory disturbances during intestinal and cerebral forms of acute radiation sickness.     

Stress signaling pathways activated by weaning mediate intestinal dysfunction in the pig

Weaning in the piglet is a stressful event associated with gastrointestinal disorders and increased disease susceptibility. Although stress is thought to play a role in postweaning intestinal disease, the mechanisms by which stress influences intestinal pathophysiology in the weaned pig are not understood. The objectives of these experiments were to investigate the impact of weaning on gastrointestinal health in the pig and to assess the role of stress signaling pathways in this response. Nineteen-day-old pigs were weaned, and mucosal barrier function and ion transport were assessed in jejunal and colonic tissues mounted on Ussing chambers. Weaning caused marked disturbances in intestinal barrier function, as demonstrated by significant (P < 0.01) reductions in transepithelial electrical resistance and increases in intestinal permeability to [3H]mannitol in both the jejunum and colon compared with intestinal tissues from age-matched, unweaned control pigs. Weaned intestinal tissues exhibited increased intestinal secretory activity, as demonstrated by elevated short-circuit current that was sensitive to treatment with tetrodotoxin and indomethacin, suggesting activation of enteric neural and prostaglandin synthesis pathways in weaned intestinal tissues. Western blot analyses of mucosal homogenates showed increased expression of corticotrophin-releasing factor (CRF) receptor 1 in the jejunum and colon of weaned intestinal tissues. Pretreatment of pigs with the CRF receptor antagonist alpha-helical CRF(9-41), which was injected intraperitoneally 30 min prior to weaning, abolished the stress-induced mucosal changes. Our results indicate that weaning stress induces mucosal dysfunction mediated by intestinal CRF receptors and activated by enteric nerves and prostanoid pathways.     

16S rRNA Gene Pyrosequencing Reveals Shift in Patient Faecal Microbiota During High-Dose Chemotherapy as Conditioning Regimen for Bone Marrow Transplantation

Gastrointestinal disturbances are a side-effect frequently associated with haematological malignancies due to the intensive cytotoxic treatment given in connection with bone marrow transplantation (BMT). However, intestinal microbiota changes during chemotherapy remain poorly described, probably due to the use of culture-based and low-resolution molecular methods in previous studies. The objective of our study was to apply a next generation DNA sequencing technology to analyse chemotherapy-induced changes in faecal microbiota. We included eight patients with non-Hodgkin’s lymphoma undergoing one course of BMT conditioning chemotherapy. We collected a prechemotherapy faecal sample, the day before chemotherapy was initiated, and a postchemotherapy sample, collected 1 week after the initiation of chemotherapy. Total DNA was extracted from faecal samples, denaturing high-performance liquid chromatography based on amplification of the V6 to V8 region of the 16S ribosomal RNA (rRNA) gene, and 454-pyrosequencing of the 16 S rRNA gene, using PCR primers targeting the V5 and V6 hypervariable 16S rRNA gene regions were performed. Raw sequence data were screened, trimmed, and filtered using the QIIME pipeline. We observed a steep reduction in alpha diversity and significant differences in the composition of the intestinal microbiota in response to chemotherapy. Chemotherapy was associated with a drastic drop in Faecalibacterium and accompanied by an increase of Escherichia. The chemotherapy-induced shift in the intestinal microbiota could induce severe side effects in immunocompromised cancer patients. Our study is a first step in identifying patients at risk for gastrointestinal disturbances and to promote strategies to prevent this drastic shift in intestinal microbiota.     

Influence of clindamycin, administered together with or without lactobacilli, upon intestinal ecology in rats

In order to evaluate whether lactobacilli could reduce antibiotic-related ecological disturbances of the normal intestinal microflora, rats were treated daily with either lactobacilli (Lactobacillus delbrueckii subsp. bulgaricus + Streptococcus thermophilus, 10⁸ cfu per animal for 6 days), clindamycin (4 mg/kg for 5 days) or a combination of both. The effects upon the following microflora-associated characteristics were evaluated: mucin degradation, conversion of cholesterol to coprostanol, inactivation of tryptic activity, presence of short-chain fatty acids and absence of beta-aspartylglycine.Clindamycin markedly influenced all characteristics except beta-aspartylglycine, resulting in a pattern very much alike what is found in germ-free animals. No significant differences were seen between the group receiving clindamycin + lactobacilli compared to the group receiving clindamycin only, even though the lactobacilli count increased in all animals receiving lactobacilli.We conclude that clindamycin markedly influences and disturbs normal intestinal microflora-related functions and that administration of lactobacilli of the type used in this study has no positive effect on diminishing these disturbances.     

Correction of intestinal dysbacteriosis in elderly patients with the use of bifidobacterin introduced by different routes

The results of the correction of disturbances in intestinal microflora in elderly patients with the use of bifidumbacterin in the form of powder or suppositories are presented. The effectiveness of the rectal administration of bifidumbacterin (by microinjections through an enema or in suppositories) is shown in comparison with the oral administration of the preparation. The administration of bifidumbacterin in suppositories for 15 days resulted in decreased content of hemolytic Escherichia below the threshold of determination in all examined patients.     

The frequency of staphylococcal colonization of the intestines in children with the manifestations of dysbacteriosis

In 2100 children of different age groups the microbiocenosis of the large intestine was studied. The study revealed that the colonization of the mucous membrane of the large intestine with staphylococci developed in 30% of children with intestinal dysbacteriosis. Young children were mainly affected (91%). The prevailing species among isolated staphylococci was S. aureus (86%), capable of persistence in the intestine (30.9%). In children non typing S. aureus strains mainly circulated (70%), and among phage-typing strains isolates of phage group III prevailed (70.2%). The colonization of the intestine with coagulase-negative staphylococci was possible (14%). Microecological intestinal disturbances in children of different age groups were characterized by different degrees of changes in normal microflora with the prevalence of opportunistic microorganisms in the microbial picture.     

Bifidogenic factors as drug preparations

The review of new data on the study of bifidobacterial factors of different origin and the probable mechanisms of their favorable action on the microflora of the intestinal tract if presented. The main emphasis is made on the analysis of data on the use of oligosaccharides, including fructo-oligosaccharides, as compounds stimulating the growth and development of bifidobacteria both in pure cultures and in intestinal microflora. Methods for the treatment of natural compounds with a view to enhancing their bifidogenic effect are presented. The possibilities and/or advantages of using bifidogenic factors in vivo and in vitro as medicinal preparations either alone or incorporated in probiotic compositions are evaluated. Suggestion has been made that the choice of the method for using bifidogenic factors may depend on the kind and severity of disturbances in indigenous microflora.     

Effect of Sonne shigella endotoxin on cholinergic regulation of intestinal circulation]

A method of extracorporeal autoperfusion and resistography of the intestinal vessels and synchronous multichannal recording the systemic blood circulation were applied to the study of the influence of the Sh. sonnei endotoxin on the cholinergic regulation of the cardiovascular system in Macacus rhesus. It was shown that development of intoxication was accompanied by the changes in the cholinergic regulation of the intestinal and systemic circulation leading to its disturbance. Possibly affection of the cholinergic control structures and disturbances of the circulation determined the development and the course of the infectious process.