Prevalence and clinical significance of pleural microbubbles in computed tomography of thoracic empyema.

AIM: To determine the prevalence and clinical significance of pleural microbubbles in thoracic empyema. MATERIALS AND METHODS: The charts of 71 consecutive patients with empyema were retrospectively reviewed for relevant demographic, laboratory, microbiological, therapeutic and outcome data. Computed tomography (CT) images were reviewed for various signs of empyema as well as pleural microbubbles. Two patient groups, with and without microbubbles were compared. RESULTS: Mean patient age was 49 years and 72% were males. Microbubbles were detected in 58% of patients. There were no significant differences between patients with and without microbubbles in regard to pleural fluid chemistry. A causative organism was identified in about 75% of cases in both. There was no difference in the rates of pleural thickening and enhancement, increased extra-pleural fat attenuation, air-fluid levels or loculations. Microbubbles were diagnosed after a mean of 7.8 days from admission. Thoracentesis before CT was performed in 90 and 57% of patients with and without microbubbles (p=0.0015), respectively. Patients with microbubbles were more likely to require repeated drainage (65.9 versus 36.7%, p=0.015) and surgical decortication (31.7 versus 6.7%, p=0.011). Mortalities were 9.8 and 6.6% respectively (p=0.53). CONCLUSION: Pleural microbubbles are commonly encountered in CT imaging of empyema but have not been systematically studied to date. Microbubbles may be associated with adverse outcome such as repeated drainage or surgical decortication. The sensitivity and specificity of this finding and its prognostic implications need further assessment.

The response of Aeromonas hydrophila to oxidative stress induced by exposure to hydrogen peroxide.

Aeromonas hydrophila, an opportunist human pathogen of low virulence, was shown to display a high degree of sensitivity upon exposure to hydrogen peroxide. As with other species, Aer. hydrophila is able to develop the capacity to resist loss of viability induced by such oxidative stress. Development of stress resistance follows the archetypal profile where pre-exposure of a population to sub-lethal levels of H2O2 stimulates onset of tolerance to further exposure. Acquisition of tolerance critically requires nascent protein synthesis. Further analysis demonstrated population growth phase influences the degree of sensitivity of the organism. Late stationary phase cultures demonstrate a decreased sensitivity compared with younger populations. Significantly, it was also determined that stock culture age influenced the level of sensitivity of the derived experimental culture, where an increased stock culture age corresponded with enhanced resistance to H2O2. These data show that Aer. hydrophila population phenotype is influenced by the phenotype of the donor stock culture.

[Accidental severance of a venous catheter: diagnostic and therapeutic approach].

The most common invasive procedure performed in hospitals is the insertion of a vascular access device. This procedure has the rare complication of catheter emboli. Accidental cutting of a peripheral catheter, the use of duplex ultrasound to locate the cut and the extraction of the catheter through a venesection is described. If peripheral extraction fails, percutaneous extraction or thoracotomy should be tried, in that order. The immediate precautions have an impact on the final results.

Incidence of mesophilic Aeromonas within a public drinking water supply in north-east Scotland.

The motile mesophilic Aeromonas are ubiquitous to a wide variety of aquatic environments including drinking water distribution systems. Concern over the presence of mesophilic Aeromonas in public drinking water supplies has been expressed in recent years as it has been regarded as a pathogenic organism of importance in gastroenteritis. A major drinking water distribution system in north-east Scotland was monitored over a 12 month period to determine the prevalence of mesophilic Aeromonas. These data were examined in relation to chlorine concentration, pH, temperature, rainfall and the standard bacteriological indicators of water quality. Aeromonas were isolated to varying degrees from 21 of the 31 reservoirs investigated. The maximum recovery observed during the study was 605 cfu in 300 ml. The probability of isolation generally decreased with increasing levels of chlorination, although this oxidant was found to be ineffective in many reservoirs. Certain reservoirs with poor chlorination profiles yielded very few isolates, whereas some highly chlorinated sites liberated Aeromonas frequently and in relatively high numbers. A seasonal pattern in the incidence of Aeromonas emerged with infrequent isolation during the winter period increasing to a peak during the summer, with most isolates recovered when water temperature was > 12 degrees C. An association was demonstrated between the pattern of Aeromonas isolations and that of rainfall. No relationship was apparent between incidence of Aeromonas and total heterotrophic plate counts.

False-positive coliform reaction mediated by Aeromonas in the Colilert defined substrate technology system.

The Colilert defined substrate technology system allows specific, one-step detection of both coliforms and Escherichia coli while claiming to suppress the influence of non-coliform heterotrophs. The Colilert assay was examined in order to determine whether organisms from the genus Aeromonas could interfere and cause production of a false-positive coliform result as aquatic Aeromonas are known to constitute a fraction of the heterotrophic population found in drinking water. Results obtained clearly demonstrate that Aeromonas sp. can elicit a positive coliform type reaction at very low densities. Cell suspensions as low as 1 x 10(1) cells 10 ml-1 were observed to yield a positive reaction using Colilert reagent 4 weeks short of shelf-life expiry. Use of aged Colilert for monitoring water quality could lead to overestimation of coliforms as Aeromonas have been identified in many treated drinking water supplies.

[Cystadenocarcinoma with peritoneal involvement (pseudomyxoma peritonei). Is surgical resection alone sufficient?]. / Cystadénocarcinome avec atteinte péritonéale (pseudomyxome péritonéal). L'exérèse chirurgicale seule est-elle suffisante?

We present our experience of 10 cases of pseudomyxoma peritonei treated in our regional hospital between 1978 and 1992. We note the rarity of this disease; the catastrophic macroscopic appearance may mislead the in experienced surgeon. Preoperative diagnosis is usually easy when confronted with a mass in an ascitic abdomen, with the help of ultrasonography and CT-scan, and above all after abdominal puncture which produces pathognomonic gelatinous fluid. Most cases are derived from the ovary and appendix. Treatment is surgical and aggressive; we adopt the protocol proposed by Sugarbaker which combines repeated surgery and local and systemic chemotherapy. The relatively good survival, even in the malignant cases, seems to be improved by this treatment.

Metabolism of 25-OH-vitamin D3 by peritoneal macrophages from CAPD patients.

The active metabolite of vitamin D, 1,25-dihydroxycholecalciferol (1,25(OH)2D3), is produced mainly by the kidney, but there is evidence for extrarenal production in certain circumstances. We studied whether peritoneal macrophages (PM) from CAPD patients were capable of metabolizing 25-OH-D3 to 1,25(OH)2D3. We found that PM were able to metabolize 25-OH-D3 in vitro; the main product following 16 hours of incubation was 19-nor, 10-oxo, 25-OH-D3 with smaller amounts of 1,25(OH)2D3. However, after shorter incubations of three and five hours a larger portion of 1,25(OH)2D3 was produced. The metabolism of 25-OH-D3 was greatly enhanced in PM harvested during episodes of peritonitis. This property was specific for PM of CAPD patients, and was not found in PM from normal subjects. However, incubation of control PM with peritoneal effluent from CAPD patients resulted in induction of the ability of these cells to metabolize 25-OH-D3. This induction was enhanced by preincubation with peritoneal effluent from CAPD patients suffering from peritonitis. Prostaglandin E2 was found to be involved in this synthesis: addition of PGE2 to normal PM induced metabolism of 25-OH-D3, and incubation of PM from CAPD patients with indomethacin decreased the metabolism of 25-OH-D3. The vitamin D metabolites produced by PM from CAPD patients could have a role in immunological resistance to peritoneal infections.