Picotamide inhibition of excess in vitro thromboxane B2 release by colorectal mucosa in inflammatory bowel disease.

BACKGROUND: Inflammatory bowel disease is associated with increased mucosal release of eicosanoids. Among these, thromboxane A2 has been proposed as a possible inflammatory mediator; its suppression may be a useful therapeutic option. METHODS: Using a tissue incubation technique, we compared release of immunoreactive thromboxane B2 by colonic biopsies from patients with ulcerative colitis, Crohn's disease and controls, and assessed the inhibitory effect of picotamide, a thromboxane synthesis inhibitor-receptor antagonist, which has been widely used in Italy for management of ischaemic heart and cerebrovascular disease. RESULTS: Increased amounts of thromboxane B2 were released from biopsies from patients with active ulcerative colitis (median 238 pg/20 min/mg wet weight (interquartile range 147- 325), n = 12) and active Crohn's disease (252 (174-450), 6) compared with those from patients with quiescent ulcerative colitis (95 (61- 140), 12) or Crohn's disease (105 (57-201), 13), or controls (136 (64- 206), 8). Incubation with picotamide at concentrations between 100 microM and 1 mM reduced thromboxane B2 release (IC50 890 microM). CONCLUSION: Since increased thromboxane A2 production may have pathogenetic importance, thromboxane synthesis inhibitor-receptor antagonists such as picotamide merit therapeutic trial in the management of inflammatory bowel disease.     

Biochemical, Enzymatic, and Serological Differentiation of Peptococcus indolicus (Christiansen) Sørensen from Peptococcus asaccharolyticus (Distaso) Douglas

Peptococcus indolicus (formerly Micrococcus indolicus) is an asaccharolytic anaerobic coccus that is frequently isolated from udder secretions from cases of heifer and dry-cow mastitis (summer mastitis). To facilitate better identification and its differentiation from Peptococcus asaccharolyticus, a variety of biochemical, enzymatic, and serological properties were studied. Seventy-nine strains of P. indolicus of bovine origin and 10 strains of P. asaccharolyticus of human origin were examined using the API 20A and API-ZYM test kit systems. In addition, production of extracellular enzymes by using sensitive substrate-containing agar plate tests, production of peptocoagulase (a plasma-clotting factor), hemolytic properties, metabolic end products by gas chromatography, and serological characteristics with a set of P. indolicus typing antisera were investigated. P. indolicus and P. asaccharolyticus were not satisfactorily differentiated solely by the API 20A system. P. indolicus differed from P. asaccharolyticus in producing H(2)S, reducing nitrate to nitrite, producing peptocoagulase, possessing alkaline phosphatase, and producing large amounts of propionate from lactate. Moreover, none of the strains of P. asaccharolyticus was typable with the P. indolicus typing antisera. The majority (88%) of P. indolicus strains also gave weak hydrolysis of ribonucleic acid, and 6 out of 79 produced deoxyribonuclease. All strains in this study were sensitive to metronidazole (5 mug) by disk diffusion tests.     

Phylogenetic analysis of the spirochetes Borrelia parkeri and Borrelia turicatae and the potential for tick-borne relapsing fever in Florida

Isolates of Borrelia turicatae, Borrelia parkeri, and the Florida canine borrelia (FCB) were examined to further phylogenetically characterize the identities of these spirochetes in the United States. DNA sequences of four chromosomal loci (the 16S rRNA gene, flaB, gyrB, and glpQ) were determined for eight isolates of B. turicatae and six isolates of B. parkeri, which grouped the spirochetes into two distinct but closely related taxa (>98% sequence identity) separate from Borrelia hermsii. The FCB was clearly separated with the group identified as B. turicatae, confirming this bacterium as a relapsing fever spirochete. Therefore, the potential for tick-borne relapsing fever in humans and other animals exists in Florida and future efforts are needed to determine the enzootic hosts and distribution of this spirochete in the southeastern United States. Analysis of plasmids demonstrated both linear and circular forms in B. turicatae but only linear plasmids in B. parkeri, which should be of interest to investigators concerned with plasmid diversity and evolution within this group of spirochetes.     

Regulation of production of type 1 pili among urinary tract isolates of Escherichia coli.

The piliation and hemagglutination properties of 54 consecutive Escherichia coli isolates from women with recurrent urinary tract infections were studied. Mannose-sensitive hemagglutination (MSHA) of guinea pig erythrocytes, characteristic of type 1-piliated bacteria, was produced by 75% of the isolates, 32% produced mannose-insensitive hemagglutination, and 14% produced no hemagglutination reaction. The production of type 1 pili was examined in those strains that produced MSHA only. Studies with antiserum prepared against purified pili suggested that at least three subtypes of type 1 hemagglutinins were represented among the isolates. All of the type 1-piliated isolates produced MSHA after serial subculture in static broth. After growth on agar, selected type 1-piliated isolates were subdivided into two groups. Many strains apparently suppressed piliation during growth on agar (regulated variants); all colonies became MSHA negative and were composed of nonpiliated cells as shown by electron microscopy. The loss of the MSHA phenotype often occurred after a single overnight passage on agar, and any remaining hemagglutinin was gradually lost with one to three additional passages. Seven strains, however, retained a significant hemagglutination titer after multiple subcultures on agar, and they produced colonies consisting of a mixed population of piliated and nonpiliated cells. These strains were apparently able to oscillate between states of pilus expression and nonexpression during growth on agar (random phase variants). When nonpiliated cells isolated from the mixed, random variant population were plated on agar, they gave rise to hemagglutination-positive colonies that consisted of both piliated and nonpiliated cells. The distinction between random variants and regulated variants was also observed in shaking broth cultures inoculated with nonpiliated cells. The random variants produced MSHA-positive cultures composed of piliated and nonpiliated cells, whereas the regulated strains remained nonpiliated. The results indicate that type 1 pili are a predominant adhesin of uropathogenic E. coli and that during growth on agar only about one-fourth of the type 1-piliated isolates regulate pilus expression by random phase variation.     

IgG antibodies against anaerobic bacteria in blood donor sera.

Fifty-six blood donor sera were examined by indirect immunofluorescence for IgG antibodies to a selection of anaerobic bacterial strains, often isolated from wound cultures. Another 25 sera were examined by IgG antibodies to six NCTC Bacteroides strains. A wide range of IgG antibody titres were found against Fusobacterium, Clostridium, and anaerobic streptococcal species. Very low titres were found against the Bacteroides strains. It is suggested that the testing of a single serum specimen for IgG antibodies against a representative collection of Bacteroides fragilis strains could be helpful in verifying a clinical suspicion of infection with these organisms.