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[Photoinactivation of microorganisms in the presence of photosensitizers].

Two photosensitizing preparation for the photodynamic therapy of oncological diseases have been obtained. As revealed in this study, under experimental conditions their action suppresses the growth of Enterococcus faecalis and Staphylococcus aureus, which may be of great importance for the treatment of infections. And in contrast to antibiotic therapy, their use may not affect the development of normal intestinal microflora. The study has shown that their derivatives with the residues of carbonic (or muramic) acids more intensively penetrate microorganisms through their cell walls. This makes in possible to expand the spectrum of action of the preparations. The proposed method permits the rapid analysis of the photochemical activity of preparation for photodynamic therapy in the process of their development.

Bacteriological Techniques↗

[Formation of cyclic adenosine-3',5'-monophosphate in phagocytosis].

The content of cAMP in the phagocytizing macrophages increased, especially in the phagocytosis of live microbes. cAMP formed in phagocytosis was determined in the incubation medium, whereas in the cells its content remained practically unchanged. In the administration of E. coli 055 to the germ-free guinea pigs the concentration of cAMP was found to be increased in the mucosa cells of the small intestine and in the blood serum; this fact indicated that adenylcyclase system participated in the reactions of the interrelations of the microorganisms with the epithelial cells of the smal intestiine.

Animals↗

Isolation of Salmonella using three selective enrichment broths from sausages naturally contaminated. Its relationship with other microorganisms that produce food toxi-infections.

Recently a great number of cases of human salmonellosis has been observed, and contaminated foods are the most important source of gastro-intestinal diseases by Salmonella. A comparative study of the efficiency of Salmonella spp. isolation from different kinds of sausage was carried out, using selenite-cystine (SC), Müller-Kauffmann tetrathionate (MK) and Rappaport-Vassiliadis (RV/43) broths. In addition, other microorganisms that produced food toxi-infections were investigated. The percentage of Salmonella detection using RV/43 broth is superior to those obtained by the MK/43 and SC/36 procedures. The first medium cited produces a higher recovery of different Salmonella strains and serotypes, and the inhibitory effects observed on the interferent competitive organisms are higher than the other broths.

Animals↗

Histological alterations of intestinal villi in chickens fed dried Bacillus subtilis var. natto.

Two experiments were conducted. In experiment 1, chickens were fed dried Bacillus subtilis var. natto for 3 or 28 days. Growth performance and internal organs were not different from controls, but feed efficiency tended to be improved in the 28-day feeding. In these birds, blood ammonia concentration was decreased (P<0.05). Blood glucose concentration, and amylase and lipase activity in the intestinal content were not significantly different among dietary groups. These results suggest that the B. subtilis natto depressed ammonia concentration. In experiment 2, chickens were fed dietary B. subtilis natto for 28 days. These birds had a tendency to display greater growth performance and intestinal histologies, such as villus height, cell area and cell mitosis, than the controls. Flat cell outline on the duodenal villus surface in controls developed large, protruded cell clusters and cell protuberances after feeding of dietary B. subtilis natto. These results indicate that intestinal function was activated by the depressed blood ammonia concentration in the body of the chicken. The present results may suggest that the B. subtilis natto has the potential to be a beneficial microorganism in chickens.

Amylases↗

[Modern methods for the evaluation of qualitative and quantitative changes in the characteristics of intestinal and vaginal microflora].

Disturbances in normal intestinal and vaginal microflora in women have recently become quite frequent. This accounts for the need of bacteriological laboratories for introduction of reliable methods for the diagnosis of such disturbances. Correct methodological approaches to objective evaluation of the state of intestinal and vaginal microflora are described. The methods used in the study of anaerobic microflora (lacto- and bifidobacteria, eubacteria, peptostreptococci, clostridia, bacteriods, fusobacteria) and facultative anaerobic microorganisms (enterobacteria, staphylococci, streptococci, Gardnerella, fungi of the genus Candida) have been analyzed. All stages of the study are described in consecutive order: the transportation of the material under study, its treatment in a laboratory, the spectrum of selective nutrient media for the isolation of microorganisms, methods of their identification.

Bacteria↗

Probiotics: a role in the treatment of intestinal infection and inflammation?

Probiotic therapy is based on the concept of normal healthy microflora. The development of novel means of characterising the gut microflora, in particular those based on the different levels of conservation in the ribosomal RNA sequences of different genera, have opened up new angles on the role of the gut microflora in health and disease. Components of the human intestinal microflora or organisms entering the intestine may have harmful or beneficial effects on human health. Abundant evidence implies that specific strains selected from the healthy gut microflora exhibit powerful antipathogenic and anti-inflammatory capabilities, and are consequently involved with enhanced colonisation resistance in the intestine. Realisation of this has led to the introduction of novel modes of therapeutic and prophylactic intervention based on the consumption of mono and mixed cultures of beneficial live microorganisms as probiotics.

Acute Disease↗

Probiotics in the new millennium.

Beneficial effects on human health by specific probiotic microorganisms such as prevention of gastrointestinal tract infections immune stimulation, and balancing of the intestinal microflora have been established in numerous clinical trials. The successful probiotic strains which are mainly members of Lactobacillus and more recently Bifidobacterium naturally found in the human intestinal tract, have been traditionally incorporated into fermented milk products but have excellent potential for further inclusion in functional foods and health-related products. While the health claims are generally accepted by both scientists and consumers, often the molecular mechanisms underlying the probiotic properties remains controversial. Further progress concerning the molecular basis of probiotic traits will give vital reinforcement to the probiotic concept and is a prerequisite for rational development into further applications. In this review, current research on the genetics of properties of the intestinal lactobacilli that may contribute to the activity and effectiveness of probiotics is described. The potential of molecular biology for future probiotic applications is addressed and a probiotic strains developed by modern biotechnology with advantages for specific consumers is presented.

Animals↗

Fiber and gastrointestinal microecology.

The gastrointestinal tract contains a unique microecology. Microorganisms living in the mouth, stomach, and most importantly in the small and large intestines produce enzymes which help metabolize certain ingested foods, as well as maintain important body homeostatic mechanisms such as the bile salt enterohepatic circulation. Recent awareness of the importance of poorly digested foods such as cellulose, hemicellulose, pectins, and lignins, as well as selectively absorbed long-chain polysaccharides, has stressed the importance of the relationship of food to the microflora. This intestinal microecology has definite effects on the human host in cholesterol metabolism, glucose tolerance, and may explain such diseases as carcinoma. The exacting details of the intestinal microecology need further elaboration.

Bile Acids and Salts↗

Unusual microbial xylanases from insect guts.

Recombinant DNA technologies enable the direct isolation and expression of novel genes from biotopes containing complex consortia of uncultured microorganisms. In this study, genomic libraries were constructed from microbial DNA isolated from insect intestinal tracts from the orders Isoptera (termites) and Lepidoptera (moths). Using a targeted functional assay, these environmental DNA libraries were screened for genes that encode proteins with xylanase activity. Several novel xylanase enzymes with unusual primary sequences and novel domains of unknown function were discovered. Phylogenetic analysis demonstrated remarkable distance between the sequences of these enzymes and other known xylanases. Biochemical analysis confirmed that these enzymes are true xylanases, which catalyze the hydrolysis of a variety of substituted beta-1,4-linked xylose oligomeric and polymeric substrates and produce unique hydrolysis products. From detailed polyacrylamide carbohydrate electrophoresis analysis of substrate cleavage patterns, the xylan polymer binding sites of these enzymes are proposed.

Amino Acid Sequence↗

Human colonic subepithelial myofibroblasts modulate transepithelial resistance and secretory response.

The epithelium of the gastrointestinal tract transports ions and water but excludes luminal microorganisms and toxic molecules. The factors regulating these important functions are not fully understood. Intestinal myofibroblasts lie subjacent to the basement membrane, at the basal surface of epithelial cells. We recently showed that primary cultures of adult human colonic subepithelial myofibroblasts express cyclooxygenase (COX)-1 and COX-2 enzymes and release bioactive transforming growth factor-beta (TGF-beta). In this study we have investigated the role of normal human colonic subepithelial myofibroblasts in the regulation of transepithelial resistance and secretory response in HCA-7 and T84 colonic epithelial cell lines. Cocultures of epithelial cells-myofibroblasts and medium conditioned by myofibroblasts enhanced transepithelial resistance and delayed mannitol flux. A panspecific antibody to TGF-beta (but not piroxicam) antagonized this effect. In HCA-7 cells, myofibroblasts downregulated secretagogue-induced change in short-circuit current, and this effect was reversed by pretreatment of myofibroblasts with piroxicam. In contrast to HCA-7 cells, myofibroblasts upregulated the agonist-induced secretory response in T84 cells. This study shows that intestinal subepithelial myofibroblasts enhance barrier function and modulate electrogenic chloride secretion in epithelial cells. The enhancement of barrier function was mediated by TGF-beta. In contrast, the modulation of agonist-induced change in short-circuit current was mediated by cyclooxygenase products. These findings suggest that colonic myofibroblasts regulate important functions of epithelial cells via distinct secretory products.

Biological Transport↗

[Prevalence of Blastocystis hominis among food handlers from Caroni municipality, Bolivar State, Venezuela].

A cross-sectional survey was conducted to determine the prevalence of Blastocystis hominis infection in a random sample of apparently healthy food handlers. A total of 415 individuals attending the Manoa Urban Outpatient Clinic (Caroní Municipality, Bolívar State, Venezuela) in the Adult Hygiene Program and who requested health certification to work as food handlers were studied. Stool samples obtained by spontaneous evacuation were examined by direct microscopy and the Willis concentration method. A total of 150 individuals were infected (36.14%), 107 (25.78%) of whom with B. hominis. There was no difference between males and females (p > 0.05), but there was a significant difference between ages (chi(2) = 12.17; g.l. = 4), with infection more frequent between 18 and 27 years. In 71.02% of the cases, B. hominis was the only parasite. Giardia lamblia was the parasite most frequently associated with B. hominis (2.41%). In the majority (85%) of infected individuals, less than five microorganisms per microscopic field were observed. We conclude that B. hominis is a frequent intestinal parasite among food handlers in Caroní Municipality, Bolivar State, Venezuela.

Adolescent↗

[Potential risk of pharmacologically induced hypochlorhydria in the treatment of peptic ulcer disease].

The introduction of the very potent anti-secretory ulcer-healing drugs that effectively inhibit gastric acid secretion actualized the problem of pharmacologically induced hypochlorhydria. Potential dangers of hypochlorhydria relate mainly to the observation that various microorganisms normally destroyed by gastric acid survive and proliferate in the stomach and small intestine and thus increase the risk of the serious gastrointestinal infections. It has been also suggested that the proliferation of the intragastric bacteria may convert dietary nitrate into nitrite that may be nitrosated to carcinogenic N-nitroso compounds. Increased risks of nosocomial pneumonia or acute stress bleeding in ventilated intensive care unit patients become additional hazards during the treatment with antisecretory agents. Moreover, there is now evidence that after a course of treatment with antisecretory agents peptic ulcer recur more rapidly. Obviously, enthusiasm resulting of the great efficacy of antisecretory drugs in promoting ulcer healing must be hampered by previous considerations.

Anti-Ulcer Agents↗

[A preliminary study of the postburn intestinal biological barrier injury in severely burned rats].

OBJECTIVE: To investigate the postburn change in the intestinal biological barrier in severely burned rats. METHODS: Wistar rats inflicted by 30% TBSA III degree scalding on the back were employed as the model. The samples were harvested at 24, 48, 72 and 96 postburn hours (PBHs), respectively with the employment of microorganism analysis, biochemical and radio-immune methods for the study. The membranous flora in cecum, the mucin and sIgA in intestinal content, the intestinal endotoxin and bacterial translocation rate and quantification analysis and the endotoxin content in cava vein were observed. RESULTS: The total intestinal membranous flora amount decreased, especially and obviously did the anaerobic bacteria such as bifidobacteria. But aerobic ones increased. In addition, The fungus and enterobacteria exhibited rapid overgrowth. This lead to evident imbalance between anaerobic and aerobic bacteria and to the destruction of intestinal biological barrier and the decrease of colonization resistance. As a result, the intestinal bacterial translocation rate increased markedly. The endotoxin content in the cava and intestinal containing increased, while the mucin and sIgA contents decreased. CONCLUSION: Intestinal biological barrier could be severely damaged after major burn, which might be one of the causes of postburn intestinal infection.

Animals↗

Bowel microorganisms--a target for selective antimicrobial control.

This article reviews the eight factors that determine the outcome of selective antimicrobial control (SAC) a technique aimed at the clearance of intestinal Gram-negative bacillary carriage by means of lethal faecal anti-microbial concentrations. They are as follows: (i) the carrier state; (ii) compliance; (iii) SAC aiming at prophylaxis vs treatment; (iv) minimum bactericidal concentration (MBC) of the antimicrobial; (v) dosage; (vi) pharmacokinetics; (vii) faecal inactivation; and (viii) microorganisms to be controlled. In the second part, non-absorbable SAC regimens are compared with absorbable trimethoprim/sulphamethoxazole (TMP/SMZ) and the fluoroquinolones in different clinical settings including neutropenia, intensive care, hepatic encephalopathy, liver transplantation and the salmonella carrier state. Ablation of gut carriage and superinfections are the main endpoints reviewed in this article. The newer fluoroquinolones are potent SAC agents to deal with enterobacteria. Pseudomonads are the major gap in their SAC spectrum. TMP/SMZ emerges as a SAC agent of limited value, whilst the newer non-absorbable combination of polymyxin/tobramycin seems to be the most potent SAC programme since it has activity against pseudomonads. In a third part, three current issues--the emergence of resistance, the selectivity and the tissue effect are discussed. Finally, a potent fluoroquinolone combined with oral polymyxin/tobramycin seems to be the most effective SAC programme currently available to control enterobacteria and pseudomonads in patients in whom bacterial translocation is a risk with minimal risk of resistance emerging.

4-Quinolones↗

The dendritic cell: its role in intestinal inflammation and relationship with gut bacteria.

Dendritic cells are antigen presenting cells that are likely to be pivotal in the balance between tolerance and active immunity to commensal microorganisms that is fundamental to inflammatory conditions, including Crohn's disease and ulcerative colitis. Interactions between dendritic cells and microbial products are discussed and how they contribute to regulation of immune responses. The concept that interactions between dendritic cells and commensal organisms may be responsible for maintaining intestinal immune homeostasis is also explored.

Bacterial Infections↗

The prevalence of different porcine phenotypes in the Netherlands concerning adherence of K88-positive Escherichia coli to intestinal epithelium.

Jejunal brush border samples from 101 pigs were tested for the presence of K88 receptor sites. Specific adhesion of K88-bearing microorganisms did not occur in nearly 50 percent of the samples. About 40 percent of the test samples were adhesion positive for the prevailing K88ac antigen. The different porcine phenotypes were equally distributed over the country.

Adhesiveness↗

[Pathogenesis of pancreatogenic sepsis].

The intestinal tract is the motor of sepsis in the "gut-MOF hypothesis". Acute pancreatitis causes an early severe reduction of intestinal microcirculation with consequent production of radicals and cytokines damaging intestinal integrity. The intestinal organ dysfunction syndrome results in a breakdown of barrier function and a loss of propulsive activity. This leads to microbial overgrowth and bacterial translocation. This liberates cytokines and causes secondary pancreatic infection after lymphatic and systemic bacterial dissemination. Infected pancreatic necrosis by enteric microorganisms is the main cause of pancreatic sepsis.

Bacterial Translocation↗

Intestinal infections in patients with the acquired immunodeficiency syndrome (AIDS). Etiology and response to therapy.

STUDY OBJECTIVE: To determine the frequency of pathogenic gastrointestinal microorganisms in patients with the acquired immunodeficiency syndrome (AIDS) and diarrhea, and to determine if treatment for identifiable microorganisms improves symptoms. DESIGN: Prospective, consecutive sample study. SETTING: Referral-based clinic and wards, National Institutes of Health. PATIENTS: Twenty of twenty-two consecutive homosexual males with AIDS and diarrhea, and 10 homosexual males with AIDS without diarrhea. INTERVENTIONS: All patients had a complete physical examination; serial stool examinations for viral, bacterial, fungal, and protozoan pathogens; and esophagogastroduodenoscopy and colonoscopy to obtain duodenal fluid and mucosal tissue to analyze for enteric pathogens or histopathology. Patients with diarrhea had a malabsorption evaluation. Patients with treatable pathogenic microorganisms received standard antimicrobial therapy. MEASUREMENTS AND MAIN RESULTS: The 20 patients with AIDS and diarrhea had greater weight loss, lower mean numbers of helper-inducer (OKT4) lymphocytes, and a higher incidence of extraintestinal opportunistic infections than the 10 patients without diarrhea. One or more enteric pathogen was identified in 17 of 20 patients (85%; 95% confidence interval [CI], 65% to 96%) with diarrhea. Only 1 patient without diarrhea was infected with an enteric pathogen. Nineteen of twenty patients with diarrhea and all 10 patients without diarrhea had chronic inflammatory changes in their intestinal biopsy specimens. Sixteen patients with identifiable enteric pathogens and diarrhea were treated; 11 (69%; 95% CI, 43% to 87%) showed microbiologic, histologic, or clinical improvement. CONCLUSIONS: Thorough diagnostic evaluation can lead to the identification of enteric pathogens in a high percentage of patients with AIDS and diarrhea. Specific therapy can lead to symptomatic improvement.

Acquired Immunodeficiency Syndrome↗