Complete genome sequence of Vibrio fischeri: a symbiotic bacterium with pathogenic congeners

Vibrio fischeri belongs to the Vibrionaceae, a large family of marine gamma-proteobacteria that includes several dozen species known to engage in a diversity of beneficial or pathogenic interactions with animal tissue. Among the small number of pathogenic Vibrio species that cause human diseases are Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus, the only members of the Vibrionaceae that have had their genome sequences reported. Nonpathogenic members of the genus Vibrio, including a number of beneficial symbionts, make up the majority of the Vibrionaceae, but none of these species has been similarly examined. Here we report the genome sequence of V. fischeri ES114, which enters into a mutualistic symbiosis in the light organ of the bobtail squid, Euprymna scolopes. Analysis of this sequence has revealed surprising parallels with V. cholerae and other pathogens.     

Sulfasalazine and Mesalazine for the Maintenance Therapy of Crohn's Disease: A Meta-analysis

Objective: The aim of this meta-analysis was to determine whether therapy with sulfasalazine or mesalazine is effective in the maintenance of clinical remission in patients with Crohn's disease. Methods: Computerized searches of bibliographic databases were carried out to identify studies published up to October 1993 that were randomized controlled trials of sulfasalazine or mesalazine as single drug therapy in the prevention of symptomatic disease relapse in quiescent Crohn's disease. We extracted and statistically aggregated data from the trials, using a fixed effects model. Results: A total of 10 eligible trials involving a total of 1022 patients were identified. Therapy with sulfasalazine or mesalazine reduces the risk of clinical relapse of Crohn's disease after 12 months [relative risk (RR) = 0.77, 95% confidence interval (CI) 0.64–0.92]. The benefit is less apparent at 3–6 months [RR = 0.86, 95% CI 0.67–1.09]. Subgroup analysis indicated that therapeutic benefit exists for mesalazine but not for sulfasalazine [RR for mesalazine = 0.63, 95% CI 0.50–0.79; RR for sulfasalazine = 1.08, 95% CI 0.81–1.44]. Conclusions: Maintenance therapy with mesalazine or sulfasalazine reduces the risk of clinical disease relapse in Crohn's disease after 1 yr. This benefit is seen primarily in the more recent studies that have used mesalazine as the therapeutic agent.     

Pericardial effusion early in acute myocardial infarction

The incidence and significance of pericardial effusions early in acute myocardial infarction remain unclear. Using two-dimensional echocardiography, 172 patients with an acute myocardial infarction were evaluated within 72 h of presentation. Thirty patients (17%) had a pericardial effusion (29 small, 1 moderate) while 142 (83%) did not. No patient developed cardiac tamponade or required pericardiocentesis. Patients with pericardial effusions had higher peak creatine kinase as compared to patients without effusions (2036 +/- 1466 vs. 1483 +/- 1241, p less than 0.05) and a greater number of aneurysms (20% vs. 6%, p less than 0.05). In-hospital mortality was higher in the patients with pericardial effusions (10% vs. 2%, p less than 0.05). In conclusion, pericardial effusions are common in the early AMI period but are generally small and hemodynamically insignificant. They are associated with larger infarcts and greater mortality.     

Oral administration of human rotavirus to volunteers: induction of illness and correlates of resistance

Four of 18 volunteers challenged orally with human rotavirus strain D (subgroup 2, serotype Wa) developed a diarrheal illness two to four days after inoculation. Viral shedding was detected in five of the 18 volunteers, whereas 12 (67%) developed serologic evidence of infection. Two volunteers who developed diarrheal illness after the initial inoculation were given the same inoculum 19 months later; neither developed diarrhea, although one developed constitutional and gastrointestinal symptoms. The presence of preinoculation serum immunofluorescent antibody to rotavirus strain D or high levels of neutralizing antibody to Wa or reassortant DS-1 human rotavirus correlated with resistance to diarrheal illness. Although prechallenge serum antibody correlated with resistance to diarrhea and/or shedding of rotavirus, the relationship of preexisting local neutralizing activity in intestinal fluid was less clear-cut.     

Bleeding during thrombolytic therapy for acute myocardial infarction: mechanisms and management

Hemorrhage is the major adverse effect of thrombolytic therapy, but its incidence can be reduced by careful selection of patients and avoidance of unnecessary invasive procedures. More than 70% of bleeding episodes occur at vascular puncture sites. Hypofibrinogenemia and elevation of fibrinogen degradation products have been weakly correlated with the risk of hemorrhage. Although depletion of factors V and VIII may occur, the role of such depletion in bleeding is unknown. Several in-vitro studies have shown plasmin-induced platelet dysfunction, but clinical data are limited. Nevertheless, the role of platelet inhibition should be considered because many patients are treated with antiplatelet agents. Most patients who have bleeding can be managed by interruption of thrombolytic and anticoagulant therapy, volume replacement, and manual pressure applied to an incompetent vessel. Protamine should be considered if heparin has been administered within 4 hours of the onset of bleeding. In the few patients who fail to respond to these conservative measures, judicious use of transfusion products may be indicated. Transfusion of cryoprecipitate, fresh frozen plasma, and platelets should be considered with clinical and laboratory reassessment after each administration. A target fibrinogen level of 1 g/L is desirable with cryoprecipitate infusion. Antifibrinolytic agents are available as a last alternative. We have developed an algorithm for using these products.     

A comparative study of herpes simplex infections in renal transplant and leukemic patients

Herpes simplex virus (HSV) reactivation and lesion formation were studied in 68 renal transplant recipients and 30 leukemic patients. Antibody titers to HSV were determined, and seropositive patients were examined three times weekly for up to one month. Surveillance cultures were taken for oral HSV, and HSV culture and cytology were done for all oral lesions found. In a smaller number of patients, immune responses were determined. HSV reactivation was similar in the transplant and leukemic groups (46.8% vs. 50%), but a significant difference in the incidence of HSV lesion formation was noted between the two groups. Of the transplant patients in whom HSV reactivated, 31.8% developed HSV lesions; of leukemic patients in whom HSV reactivated, 100% developed HSV lesions. Differences in the incidence of formation of HSV lesions in these groups of immunosuppressed patients suggest that reactivation of HSV and formation of HSV lesions may involve different mechanisms. Low levels of antibody-dependent cellular cytotoxicity were noted in leukemic patients and may contribute to increased formation of HSV lesions in this group.