Search PubMed⌕ Search

Biomedical subjects

S Bassetti

Publications and source records attributed to S Bassetti.

44 records · Page 3Linked to original sources
PubMed1993

Transmission of HIV-associated tuberculosis to healthcare workers.

OBJECTIVE: A retrospective investigation was made to compare the occupational risk of tuberculosis in personnel assisting human immunodeficiency virus (HIV)-infected and uninfected subjects with active tuberculosis. DESIGN: We retrospectively reviewed 6 years of hospital activity in 3 units where HIV-infected patients with tuberculosis are hospitalized and in 2 units where non-HIV-infected tuberculosis patients are hospitalized. The risk of occupational tuberculosis in healthcare workers who assisted HIV-infected and non-HIV-infected patients with tuberculosis was investigated. PARTICIPANTS: The risk of occupational tuberculosis in healthcare workers was studied by considering the numbers of potential source cases (hospitalized patients with tuberculosis) in the two conditions investigated (HIV-positive and HIV-negative). Both potential source cases and cases of tuberculosis in healthcare workers had to be microbiologically proven in order to be considered. RESULTS: Seven cases of tuberculosis occurred in persons who cared for 85 HIV-infected subjects with tuberculosis, while only 2 cases occurred in staff members who took care of 1,079 HIV-negative tuberculosis patients over the same period (relative risk = 44.4; 95% confidence interval = 8.5-438). CONCLUSIONS: Tuberculosis seems no longer to be a neglectable risk in healthcare workers assisting patients with HIV infection. Further study is urgently needed to see whether such unexpectedly high dissemination of tuberculosis also is demonstrable in the community.

HIV Infections↗
PubMed1992

Induction of nitric oxide synthase is a necessary precondition for expression of tumor necrosis factor-independent tumoricidal activity by activated macrophages.

Various bacteria and bacterial products induce in pure, lymphocyte-free bone marrow-derived mononuclear phagocytes (BMMø) the generation of tumor necrosis factor, nitric oxide (NO) synthase, NO and nitrite (NO2-), the flow of L-arginine to citrulline, and tumoricidal activity. The flow of L-arginine to citrulline and formation of NO/NO2- on the one hand and expression of tumoricidal activity were not always closely related; however, these parameters were suppressed in a dose-dependent manner by the flavoprotein inhibitor, diphenyleneiodonium (DPI) and the L-arginine analogue, NG-monomethyl-L-arginine (NMMA). The findings support the concept of a central role of the NO synthase pathway in the generation of tumor necrosis factor-independent tumoricidal activity by activated macrophages but the exact conditions which enable the transfer of the lytic principle from the effector to the target cell remain to be elucidated.

Amino Acid Oxidoreductases↗
PubMed1992

Macrophage response to bacteria: induction of marked secretory and cellular activities by lipoteichoic acids.

Lipoteichoic acids (LTAs) from various bacterial species, including Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Enterococcus faecalis, and Listeria monocytogenes, were examined for the ability to induce secretory and cellular responses in a pure population of bone marrow-derived mononuclear phagocytes. Some of the highly purified LTAs, in particular LTAs from Bacillus subtilis, S. pyogenes, E. faecalis, and Enterococcus hirae, were able to affect each of the macrophage parameters measured, i.e., reductive capacity, secretion of tumor necrosis factor and nitrite, and tumoricidal activity. As after stimulation with whole organisms or other bacterial products, secretion of tumor necrosis factor induced by these LTAs reached its maximum within the first few hours of the interaction, while secretion of nitrite and tumoricidal activity required 24 to 36 h for full expression. Other purified LTAs, i.e., LTAs from Streptococcus sanguis, S. pneumoniae, and L. monocytogenes, as well as lipomannan from Micrococcus luteus affected only some of these parameters, while native LTA from S. aureus was inactive. There was no obvious correlation between biological activity and chain length, kind of glycosyl substituents, glycolipid structures, or fatty acid composition of LTAs. Deacylation of LTAs resulted in a complete loss of activity, and deacylated LTAs did not impair the activity of their acylated counterparts, suggesting that acyl chains may be essential for binding of LTA to the cell surface. The results demonstrate that some LTA species are potent inducers of macrophage secretory and cellular activities.

Animals↗
PubMed1987

[Preoperative evaluation of the patient candidate for surgical intervention on the chest: methods of study and risk factors].

The authors review the main methods designed to evaluate operability and surgical risk in candidates for chest surgery. They also report on their own experience with 135 cases operated on for thoraco-pulmonary diseases requiring surgery; in these cases, postoperative complications were studied in relation to various respiratory parameters evaluated differentially and as a whole prior to surgery. This study enabled the investigators to establish that patients with CV, FEV1, FEF25-75 and Tiffffeneau Index values below 60% of the respective theoretical reference values run a very substantial risk of postoperative complications, with a post-surgical morbidity rate of more than 60% in such patients. Similar risks are run by patients with VR values below 60% or above 120% of predicted values or with Emphysema Index values above 120% of predicted values. The author's experience with fractional bronchospirometry revealed that, in the high-risk patient sample, a predicted postoperative FEV1 value of only 800 ml/sec is a poorly selective limit.

Adolescent↗
PubMedDate not supplied

Molecular epidemiology of tuberculosis among HIV-infected persons in Switzerland: a countrywide 9-year cohort study. Swiss HIV Cohort Study.

We investigated tuberculosis transmission during a nine-year period (1988-1996) in a countrywide community-based cohort of HIV-infected persons in Switzerland (the Swiss HIV Cohort Study [SHCS]). We estimated the proportion of tuberculosis cases due to reinfection and relapse, and assessed factors which may increase the risk of tuberculosis transmission. HIV-infected persons were followed prospectively and molecular fingerprinting with insertion sequence (IS) 6110, 36-bp direct repeat, and IS6110-PCR was used to determine M. tuberculosis case clustering. Out of 7999 SHCS participants, 267 persons developed tuberculosis. 158 M. tuberculosis isolates from 138 patients were available for study. Molecular analysis identified 33 (24%) episodes of tuberculosis associated with 12 clusters including 2 to 8 patients. Two patients experienced reinfection, and nine had a relapse. Detailed contact investigation identified definite or possible epidemiological links between 21 of 33 cluster patients (64%). Multivariate logistic regression analysis did not identify any risk marker significantly associated with clustering. During a nine-year period, one fourth of tuberculosis cases were grouped in clusters within a selection of 138 HIV-infected patients. This may represent the lowest estimation of recently acquired tuberculosis infection. There were no large institutional or community outbreaks among HIV-infected participants of the Swiss HIV Cohort Study.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

"Cloud" health-care workers.

Certain bacteria dispersed by health-care workers can cause hospital infections. Asymptomatic health-care workers colonized rectally, vaginally, or on the skin with group A streptococci have caused outbreaks of surgical site infection by airborne dispersal. Outbreaks have been associated with skin colonization or viral upper respiratory tract infection in a phenomenon of airborne dispersal of Staphylococcus aureus called the "cloud" phenomenon. This review summarizes the data supporting the existence of cloud health-care workers.

Bordetella pertussis↗
PubMedDate not supplied

Influence of gastric pH changes on pharmacokinetic of a sustained-release formulation of theophylline.

The effect of magnesium-aluminum-hydroxide antacid (Maalox) on the oral absorption of theophylline anhydrous time-release capsules Somophyllin CRT was studied in eight healthy volunteers. The subjects were given 500 mg of theophylline alone or with 30 ml of antacid in a complete crossover design. Drug serum concentrations were determined by an immunoenzymatic method within 24 hours at frequent intervals. Antacid induced a significant reduction of theophylline serum levels and of the fraction absorbed at 1 and 1.5 hours of the monitoring period (less than 0.05), but no significant differences were found at later sampling time. Maalox did not influence the area under the curve from 0 to 24 hours and the peak concentrations; the time to peak was slightly but significantly longer with antacid (p less than 0.05). Our results indicate that physicochemical factors such as gastrointestinal fluid pH do not influence substantially absorption of the slow-release formulation Somophyllin.

Adult↗