No abstract

Patients with cirrhosis are predisposed to develop spontaneous bacteremias and peritonitis, mainly by enteric bacteria. Portal hypertension, by producing congestion and edema of the bowel wall, could increase the passage of bacteria from the intestinal lumen to regional lymph nodes to the systemic circulation or to both, a process termed bacterial translocation. The aim of this study was to investigate bacterial translocation at two stages of experimental portal hypertension: (a) acute (when shunting is minimal); and (b) chronic (when shunting is extensive and mimics the portal hypertension of cirrhosis). Rats were killed 2 days (acute) or 15 days (chronic) after partial portal vein ligation or control surgeries. Samples of mesenteric lymph nodes, blood, liver and spleen for standard bacteriological cultures and a fragment of ileum for histological examination were obtained. Two days after surgery, a significantly greater proportion of rats with acute portal hypertension (12 of 13 or 92%) had positive mesenteric lymph node cultures compared with both control groups: sham-operated (4 of 13 or 31%) and inferior vena cava-ligated (3 of 10 or 33%) animals (p < 0.01). However, 15 days after surgery no differences in translocation to mesenteric lymph nodes were found between rats with chronic portal hypertension (3 of 15 or 20%) and sham-operated controls (3 of 11 or 27%). In neither the acute nor the chronic rats were bacteria isolated from blood, spleen or liver. Rats with acute portal hypertension had significantly greater mesenteric inflammation than rats with chronic portal hypertension and control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

An outbreak of respiratory illness due to Branhamella catarrhalis occurred in the intermediate care unit of a Veterans Administration hospital and involved patients and staff members. Four patients had pneumonia and four had bronchitis. Infected patients were placed in a cohort separated from noninfected patients and were treated. Pharyngeal culture was used to survey prevalence in staff and all other patients on the unit; three of 18 staff members and two of 19 asymptomatic patients were positive for B. catarrhalis. A case-control study showed that respiratory therapy, steroid use, and location within the unit were significant risk factors for B. catarrhalis infection or colonization. Strains from five patients and two staff members had identical bacterial restriction endonuclease digestion patterns with three different enzymes; these patterns were distinct from those of control strains. This study is the first to document an outbreak of B. catarrhalis infection confirmed with a typing system and thus establishes B. catarrhalis as a nosocomial pathogen.

An anti-idiotypic antibody has been raised which recognizes human immunoglobulins with cold agglutinin activity of anti-I/i specificity. The pattern of reactivity of the antibody indicates that the structural basis for the epitope is located in the VH4-21 gene segment of the VHIV family, which is preferentially utilized by these cold reactive antibodies. Using this antibody, epitope expression was investigated in a panel of 72 human monoclonal allo-antibodies specific for human blood group antigens, as compared with a control panel of 39 randomly selected human monoclonal IgM antibodies of unknown specificities. The anti-blood group panel included 44 IgM and 28 IgG monoclonal antibodies against a variety of blood group antigens including the A antigen, Rh C, c, D, E, e, G antigens, and the Kidd antigens Jka and Jkb. The epitope was expressed by 64% (28/44) of the IgM anti-blood group antibodies and by 21% (6/28) of the IgG antibodies, but by only 7.7% (3/39) of the control IgM antibodies. These data indicate that the human alloimmune response to blood group antigens is biased in the use of VH gene families, with a preference for the VH4-21 gene segment of the VHIV family, or closely related gene segments. The fact that this mirrors the findings for the autoimmune cold agglutinins suggests a link in immunoglobulin gene usage between antibodies against structurally diverse antigens on the red cell surface.