Cytotoxicity towards human endothelial cells, induced by neutrophil myeloperoxidase: protection by ceftazidime.

in Mediators of Inflammation (1995), 4(6), 437-43

We investigated the effects of the antibiotic ceftazidime (CAZ) on the cytolytic action of the neutrophil myeloperoxidase-hydrogen peroxide-chloride anion system (MPO/H(2)O(2)/Cl(-)). In this system ... [more ▼]

We investigated the effects of the antibiotic ceftazidime (CAZ) on the cytolytic action of the neutrophil myeloperoxidase-hydrogen peroxide-chloride anion system (MPO/H(2)O(2)/Cl(-)). In this system, myeloperoxidase catalyses the conversion of H(2)O(2) and CI(-) to the cytotoxic agent HOCl. Stimulated neutrophils can release MPO into the extracellular environment and then may cause tissue injury through direct endothelial cells lysis. We showed that human umbilical vein endothelial cells (HUVEC) were capable of taking up active MPO. In presence of H(2)O(2) (10(-4) M), this uptake was accompanied by cell lysis. The cytolysis was estimated by the release of (51)Cr from HUVEC and expressed as an index of cytotoxicity (IC). Dose dependent protection was obtained for CAZ concentrations ranging from 10(-5) to 10(-3) M;this can be attributed to inactivation of HOCl by the drug. This protection is comparable to that obtained with methionine and histidine, both of which are known to neutralize HOCl. This protection by CAZ could also be attributed to inactivation of H(2)O(2), but when cytolysis was achieved with H(2)O(2) or O(2) (-) generating enzymatic systems, no protection by CAZ was observed. Moreover, the peroxidation activity of MPO (action on H(2)O(2)) was not affected by CAZ, while CAZ prevented the chlorination activity of MPO (chlorination of monochlorodimedon). So, we concluded that CAZ acts via HOCl inactivation. These antioxidant properties of CAZ may be clinically useful in pathological situations where excessive activation of neutrophils occurs, such as in sepsis. [less ▲]

Macroarthropod-habitat relationships in oak forests in South Belgium. 1. Environments and communities

in Pedobiologia (1995), 39(3), 243-263

[No abstract available]

Relative importance of the trophic and direct pathways on PCB contamination in the rotifer species Brachionus calyciflorus (Pallas)

in Hydrobiologia (1995)

To determine the contribution of food ingestion (trophic pathway) to PCB contamination of zooplankton in the river Meuse (Belgium), we used 14 C-labelled algae (Dictyosphaerium ehrenbergianum) to measure ... [more ▼]

To determine the contribution of food ingestion (trophic pathway) to PCB contamination of zooplankton in the river Meuse (Belgium), we used 14 C-labelled algae (Dictyosphaerium ehrenbergianum) to measure ingestion and assimilation rates in the rotifer species Brachionus calyciflorus . When the concentration of algae in the culture medium varied from 20 103 to 200 103 algal cells ml -1 (0.12 to 1 .18 mg C 1 - '), the Brachionus calyciflorus ingestion rate varied from 0 .25 ± 0 .12 to 1 .52 ± 0 .43 ng C ind -1 h-1 at 15 °C and from 0 .74 ± 0 .17 to 5 .93 ± 0.61 ng Cind-' h-1 at 20 °C . The assimilation efficiency (ratio of the assimilation rate to the ingestion rate) measured in a culture medium containing 200 103 algal cells ml`' was 55 .7 ± 5.8%. Since the PCB concentration measured in the phytoplankton of the river Meuse is about 3 pg PCBs g -1 D.W., the estimated PCB contamination of zooplankton ascribable to the trophic pathway ranges from 0 .22 ± 0 .17 to 1 .31 ± 0.77 jag PCBs g -1 D.W. at 15 °C and from 0.64 ± 0 .34 to 5 .10 ± 2 .10 pg PCBs g -1 D. W. at 20'C . The lower figure based on measurements effected at 20 ° C is comparable to the actual level measured in zooplankton samples collected in the river Meuse (0 .69 ± 0.20 pg PCBs g`' D.W.) . The applicability of the formula used in our estimate was checked in a 48-hour in vitro experiment in which the rotifers were fed contaminated algae . The PCB accumulation measured in the rotifers was found to coincide with the calculated PCB contamination . Additional experiments were carried out to determine the contribution of the direct pathway to PCB contamination of zooplankton living in the river Meuse (0.02 pg PCBs 1-1 of water; average dissolved organic matter : 3 mg C 1 -1 ). The PCB concentration in zooplankton resulting from direct uptake of PCBs from the water was estimated at 0 .19 ± 0.05 jug PCBs g -1 D.W. These results show that in zooplankton living in polluted ecosystems, PCBs are likely to accumulate via the trophic pathway to concentrations up to 30 times higher than by direct contamination . Furthermore, our estimates of PCB contamination via the trophic pathway coincide quite well with actual concentrations measured in situ . [less ▲]

Biochronostratigraphic investigations of the Pragian and Emsian stages on the southeastern border of the Paraná Basin

in 2° Simposio sobre cronoestratigrafia da bacia do Paraná (1995)

Spores et pollens, témoins remarquables de la végétation des continents depuis un demi-milliard d'années.

in Bulletin de la Classe des Sciences. Académie Royale de Belgique (1995), 6e Série

Successful abdominal aortic aneurysm resection in long-term survivors of cardiac transplantation.

in Cardiovascular Surgery (1995), 3(3), 321-4

With the improvement of survival rates following cardiac transplantation, the probability of recipients developing extracardiac disease is increased. Three cases are reported of abdominal aortic aneurysm ... [more ▼]

With the improvement of survival rates following cardiac transplantation, the probability of recipients developing extracardiac disease is increased. Three cases are reported of abdominal aortic aneurysm successfully operated on in cardiac allograft recipients 1 to 4 years after transplantation. Indications for transplantation were valvular, idiopathic and ischaemic cardiomyopathy. Post-transplant hypertension and hyperlipidaemia may have played a role in the rapid growth of the aneurysms. Cardiac function and the incidence of graft atherosclerosis were assessed before surgery by coronary angiography. All three patients were discharged from hospital. Abdominal aortic aneurysm resection may be a safe procedure in cardiac transplant patients. In view of the rapid increase in the size of the aneurysms in transplanted patients, careful screening should be performed during follow-up. [less ▲]

Calibration of α Centauri and the uniqueness of the mixing length

in Lecture Notes in Physics (1995), 458

Taking into account the uncertainties in the metallicity parameter, Z, the authors discuss the uniqueness of the mixing length convection parameter, α, by calibration of the α Centauri binary system. The ... [more ▼]

Taking into account the uncertainties in the metallicity parameter, Z, the authors discuss the uniqueness of the mixing length convection parameter, α, by calibration of the α Centauri binary system. The results support the hypothesis of a unique value of α for both stars (equal to the solar one) for high values of Z. [less ▲]

Aneurysms of the abdominal aorta: familial and genetic aspects in three hundred thirteen pedigrees.

in Journal of Vascular Surgery (1995), 21(4), 646-55

PURPOSE: Familial clustering of abdominal aortic aneurysm was first noticed in 1977. METHODS: Through questionnaire and phone inquiry, familial data on 324 probands with abdominal aortic aneurysms allowed ... [more ▼]

PURPOSE: Familial clustering of abdominal aortic aneurysm was first noticed in 1977. METHODS: Through questionnaire and phone inquiry, familial data on 324 probands with abdominal aortic aneurysms allowed the establishment of 313 multigenerational pedigrees including 39 with multiple affected patients. RESULTS: There were 276 sporadic cases (264 men, 12 women); 81 cases belonged to multiplex pedigrees (76 men; 5 women). We compared familial and sporadic male cases; the ages at diagnosis were 64.1 +/- 7.9 years and 66.0 +/- 7.3 years (p < 0.05), respectively, the ages at rupture were 65.4 +/- 6.6 years and 75.2 +/- 8.6 years (p < 0.001), and the rupture rate was 32.4% and 8.7% (p < 0.001). Survival curves were computed. Relative risk for male siblings of a male patient was 18. We performed a segregation analysis with the mixed model, the most likely explanation for occurrence of abdominal aortic aneurysm in our families was a single gene effect showing dominant inheritance. The frequency of the morbid allele was 1:250, and its age-related penetrance was not higher than 0.4. CONCLUSION: This analysis indicates the preeminence of genetic factors on multifactorial/environmental effects of the pathogenesis of abdominal aortic aneurysm. [less ▲]

Specific bovine brucellosis diagnosis based on in vitro antigen-specific gamma interferon production.

in Journal of Clinical Microbiology (1995), 33(3), 706-12

In order to improve the specificity of the diagnosis of bovine brucellosis, we developed a test which can be regarded as an in vitro correlate of the delayed-type hypersensitivity test (DTH). A mixture of ... [more ▼]

In order to improve the specificity of the diagnosis of bovine brucellosis, we developed a test which can be regarded as an in vitro correlate of the delayed-type hypersensitivity test (DTH). A mixture of cytoplasmic proteins from Brucella melitensis B115 was used as a specific antigenic stimulus in bovine whole blood culture. Supernatants harvested at 18 to 24 h after the in vitro antigenic stimulus were assayed for their gamma interferon (IFN-gamma) content by using a commercial sandwich enzyme-linked immunosorbent assay kit. The IFN-gamma assay was evaluated with 10 heifers during the course (80 days) of an experimental infection and with 14 cows from an ongoing brucellosis outbreak. All of these animals were slaughtered, and pertinent organs were subjected to classical bacteriological analyses. In addition, we analyzed 23 field cases in which false-positive serological reactions occurred. The IFN-gamma results were compared with those of the standard DTH and a battery of serological assays, and they were correlated with bacteriological data. Both for the experimental infection and for the field brucellosis outbreak, the IFN-gamma assay detected infection in more animals than any combination of the serological tests, and it detected infection earlier than these tests. Finally, none of the samples from cows showing false-positive serological reactions was classified as positive by the IFN-gamma assay, attesting to its specificity and to its usefulness in interpreting ambiguous serological results. A rapid and convenient alternative to the DTH, the IFN-gamma assay appears to be an ideal method that is complementary to the serological diagnosis protocols. [less ▲]

Ability of Bronchodilators to Prevent Bovine Experimental Respiratory Distress

in Veterinary Research (1995), 26(4), 276-283

This cross-over trial involving 6 Blue Belgian double-muscled calves aimed to investigate whether ipratropium bromide inhaled alone or in combination with clenbuterol hydrochloride could prevent the ... [more ▼]

This cross-over trial involving 6 Blue Belgian double-muscled calves aimed to investigate whether ipratropium bromide inhaled alone or in combination with clenbuterol hydrochloride could prevent the dramatic clinical and pulmonary disturbances that are observed during an experimentally induced bronchoconstriction. Inhaled bronchodilators significantly influenced the clinical and functional responses of bovines subjected to a 5-hydroxytryptamine perfusion. However, despite a mean (standard error) wash-out period of 11.2 (3.1) and 7.5 (0.9) d after the 1st and the 2nd one-day challenges, respectively, first-order carry-over effects (ie those remaining from the previous treatment), effects of the period during which the treatment was allocated and interaction effects did not allow a definitive interpretation of overall treatment differences. [less ▲]