The effects of polycyclic aromatic hydrocarbons on the immune system of fish: a review

Polycyclic aromatic hydrocarbons are an important class of environmental pollutants that are known to be carcinogenic and immunotoxic. This review summarizes the diverse literature on the effects of these pollutants on innate and acquired immunity in fish and the mechanism of PAH-induced immunotoxicity. Among innate immune parameters, many authors have focused on macrophage activities in fish exposed to polycyclic aromatic hydrocarbons. Macrophage respiratory burst appears especially sensitive to polycyclic aromatic hydrocarbons. Among acquired immune parameters, lymphocyte proliferation appears highly sensitive to polycyclic aromatic hydrocarbon exposure. However, the effects of polycyclic aromatic hydrocarbons on both specific and non-specific immunity are contradictory and depend on the mode of exposure, the dose used or the species studied. In contrast to mammals, fewer studies have been done in fish to determine the mechanism of polycyclic aromatic hydrocarbon-induced toxicity. This phenomenon seems to implicate different intracellular mechanisms such as metabolism by cytochrome P4501A, binding to the Ah-receptor, or increased intracellular calcium. Advances in basic knowledge of fish immunity should lead to improvements in monitoring fish health and predicting the impact of polycyclic aromatic hydrocarbons on fish populations, which is a fundamental ecotoxicological goal.     

Comparative activity of 9 beta-lactamines, clindamycin and metronidazole on strictly anaerobic bacteria

The in vitro activities of amoxicillin, amoxicillin-clavulanic acid, piperacillin, cefoxitin, cefotetan, cefotaxime, cefmenoxime, ceftizoxime, latamoxef, clindamycin and metronidazole, were determined by agar dilution method for 196 clinical isolates of anaerobic bacteria. No metronidazole resistant strains could be found, 10% of tested strains were resistant to clindamycin. The majority of these strains was susceptible to amoxicillin-clavulanic acid and piperacillin; less than 10% were resistant to latamoxef, cefoxitin, cefotaxime and ceftizoxime; whereas 15 to 20% were resistant to amoxicillin, cefotetan and cefmenoxime.     

Comparative study of first-line ceftriaxone and amikacin in the treatment of severe urinary tract infections in the adult

After randomization in 2 groups of 20, 40 adult patients with a severe urinary tract infection (post-urologic surgery, pyelonephritis, prostatitis, neurologic bladder dysfunction, Foley catheter) received as first-line therapy, ceftriaxone (CFX) 1 g/24 h im or amikacin (AMK) 500 mg/24 h im during at least 5 days. The clinical and bacteriological efficiency and the tolerance of the 2 agents are equivalent. In the 2 groups, all patients but one are clinically cured. In the CFX group, 2 patients had resistant organisms (E. cloacae, strepto D) to first-line antibiotic. 48 hours after the beginning and at the end of the treatment, the percentage of urine sterilization was respectively 65 and 88 in the CFX group and 50 in the AMK group. In both groups, 60% of the patients showed negative first-month follow-up urine specimen. Underlying urinary tract pathology contributed to persistence of the original infecting organism, reinfection or relapse; the responsible isolate remained sensitive to the first-line antibiotic.     

Epidemiology of severe cranial injuries in children and the prognosis of injured patients hospitalized in neurosurgery units

Over five years (1979-1983), 1,058 children who sustained injuries in the Val de Marne District (near Paris) were treated by the Emergency and Intensive Care Mobile Unit. Among these patients, 17.8% had an isolated, severe head injury (Glasgow score less than 12) and were admitted to a neurosurgical unit; the age and sex distribution in this group was comparable to that of the entire group of injured children (2/3 boys). The severe head injury was caused by a motor vehicle accident in 47% of cases and a fall in 34% of cases. One half of patients had a skull fracture; all patients with an extra-dural (14 cases) or sub-dural (7 cases) hematoma had a skull fracture. Seventy per cent of patients had cerebral edema and 25% had a meningeal hemorrhage. Immediate severe neurologic disorders (Glasgow score less than 9) were present in 53% of cases and 27% of patients had focal neurologic signs. Mean duration of the stay in the neurosurgical unit was 6 to 15 days. Mortality was 15.3%; in most cases (75%) death occurred within the first 48 hours. One-year morbidity was very significant; 67% of surviving children had residual disease, and 40% had severe sequelae.     

Value and limitations of transthoracic Doppler echocardiography in the diagnosis of thromboses of mechanical valve prosthesis. Report of 19 cases

The diagnosis of thrombosis of a valvular prosthesis is difficult especially in cases of partial thrombosis. The authors report 19 cases of partial thrombosis of mainly (16 cases) mechanical valve prostheses confirmed by radioscopy and treated either by reoperation or fibrinolysis. Mitral Valve Prostheses: 14 cases (6 Bj?rk, 7 SJM, 1 Carbomedics). All but one case showed significant prolongation of the pressure half time compared with the postoperative reference value. In one case, however, the functional parameters of the prosthesis were normal; the diagnosis was made from the finding of a mobile thrombus on the ventricular surface of the prosthesis. Aortic Valve Prostheses: 5 cases (3 Bj?rk, 1 SJM, 1 Duromedics). Continuous wave Doppler showed significant increases in the velocity of transprosthetic blood flow with respect to the postoperative reference values. Accurate analysis of the mobile elements of the prostheses was usually impossible. These results show that transthoracic Doppler echocardiography remains an excellent method of study and surveillance of mechanical valve prostheses but the limitations of the technique should be familiar to all operators.     

Approach of Pavement Surface Layer Degradation Caused by Tire Contact Using Semi-Analytical Model

New methods of degradations on the pavement’s surface, such as top-down cracking and delamination, caused by the repeated passage of heavy vehicles led to questions about the impact of the contact between the tire and the pavement. In fact, to increase the service life of the structures, future road design methods must have a precise knowledge of the consequences of the contact parameters on the state of stress and deformation in the pavement. In this paper, tractive rolling contact under the effect of friction is modeled by Kalker’s theory using a semi-analytical method (SAM). A tire profile is performed thanks to a digitization by fringes or a photogrammetry technique. The effect of rolling on the main surface extension deformations is then highlighted to study top cracking. At the end of the SAM calculation, contact areas are closed to 200 μdef, exceeding the allowable micro-deformation limit for the initiation of cracking. In addition, results on the main strain directions also give information on the direction of cracking (initiation of longitudinal or transverse cracks). The cracking then becomes evident, leading to a reduced service life.     

Effect of zinc gluconate on propionibacterium acnes resistance to erythromycin in patients with inflammatory acne: in vitro and in vivo study

Tetracyclines and macrolide antibiotics have been in use for acne treatment for more than 20 years. Since 1992 increasing resistance to these antibiotics, and especially to erythromycin, is reported with Propionibacterium acnes. Zinc salts have demonstrated their efficacy in inflammatory acne treatment as well as their bacteriostatic activity against Propionibacterium acnes. The objective of our work was firstly to determine whether the clinical anti-inflammatory efficacy of zinc salts was altered in the presence of erythromycin resistant strains in vivo, and secondly to study the in vitro and in vivo effect of zinc on the sensitivity of Propionibacterium acnes strains to erythromycin. Thirty patients with inflammatory acne were treated by zinc gluconate with a daily dose of 30 mg for two months and bacteriologic samples were taken at D0, D30 and D60. In vivo, this study displayed a reduction in the number of inflammatory lesions after a 2-month treatment whether or not Propionibacterium acnes carriage was present. Concurrently, in vitro addition of zinc salts in the culture media of Propionibacterium acnes reduced resistance of Propionibacterium acnes strains to erythromycin. Thus, association of zinc salts via a systemic route and topical erythromycin treatment seems an interesting option in the light of an increasing number of patients carrying erythromycin resistant Propionibacterium acnes strains.