Traumatic rupture of the thoracic aorta diagnosed by transoesophageal echocardiography.

Transoesophageal echocardiography is a safe and rapid means of obtaining anatomical and dynamic information about the descending aorta. It was used to confirm a suspected diagnosis of ruptured descending aorta.     

Respiratory health status in swine producers using respiratory protective devices

A cross-sectional survey on respiratory health in swine producers showed that 30% of 301 examined men usually used a dust mask when working inside a barn. They did not differ significantly from dust mask nonusers in respect to respiratory symptoms and lung function. This analysis was undertaken to determine whether the respiratory health of dust mask users was associated with reasons why they had started individual respiratory protection. The subjects were recontacted in order to identify those who started using a mask to deliberately prevent symptoms (42 men) and those who started protection because of pre-existing respiratory symptoms (44 men). Not unexpectedly, betweengroup comparisons of respiratory symptoms and lung function suggest that swine producers who wear dust masks for preventive purposes have better respiratory health than those who wear dust masks because of symptoms or those who do not use individual respiratory protection. The individual reasons for starting dust mask usage should be examined among potential determinants of the outcomes of prospective studies which can then provide more valid assessment of the effect of individual respiratory protection. © 1993 Wiley-Liss, Inc.     

Molecular characterization of water-soluble,cationic polyelectrolytes

Poly{acrylamide-co-[2-(acryloyloxy)ethyltrimethylammonium chloride]} (1) , Poly{acrylamide-co-[2-(methacryloyloxy)ethyltrimethylammonium chloride]} (2) and Poly{acrylamide-co-[3-(acryloylamino)propyltrimethylammonium chloride]} (3) with cationic monomeric unit mole fractions of 8, 25, and 50 mol-%, and the corresponding homopolymers were characterized with respect to their molecular dimensions in 1 M sodium chloride solution at 25°C in the molecular weight range from 200000 to 16000000, using light-scattering and viscometric measurements. It was possible to establish correlations between molecular weight, intrinsic viscosity and radius of gyration. Whereas a steady increase in the exponents of the [η] vs. M- and 〈R²_G〉^0,5 vs. M-relationships can be observed with increasing charge density, there is an initial decrease in the values of the exponents for 2 and 3 , when 8 mol-% of the cationic monomer is inserted into poly-acrylamide. If the charge density is increased further, these values can also be seen to rise steadily. The findings are explained by the different structures in solution, which are formed by the copolymers and homopolymers investigated due to their chemical structure. The radii of gyration were calculated from the intrinsic viscosities with the aid of the Flory-Fox equation. However, neither the results obtained with the Flory-Fox constant Φ₀= 3,69. 10²⁴ mol^?1, nor those with the value of Φ₀= 2,10. 10²⁴ mol^?1 showed good agreement with the experimentally recorded data.     

Comparison of Ampicillin-Sulbactam and Ticarcillin-Clavulanic Acid in Patients With Chronic Renal Failure: Effects of Differential Pharmacokinetics on Serum Bactericidal Activity

Study Objectives . To evaluate the pharmacodynamic antibacterial activity of ticarcillin-clavulanic acid (T-C) and ampicillin-sulbactam (A-S) combinations against reference bacterial strains in patients with end-stage renal disease maintained on long-term hemodialysis. Design . Randomized, crossover, controlled study. Setting . National Institutes of Health-funded general clinical research unit in a Veterans Administration Medical Center. Patients . Nine adult men with end-stage renal disease maintained on long-term hemodialysis. Two subjects did not complete the study due to problems of vascular access, and another withdrew for personal reasons. Interventions . On a nondialysis day, each subject was randomly administered either T-C 3.1 g or A-S 3 g as a slow intravenous infusion over 30 minutes. Serial blood samples were collected for measurement of antibiotic serum concentrations and determination of serum bactericidal titers. Following a washout period, the study was repeated with the alternative antibiotic combination. Measurements and Main Results . The mean observed apparent β-half-life of clavulanic acid was substantially shorter than that for the other three drugs. The bactericidal activity of both A-S and T-C against non-β-lactamase-producing (Nβ-LP) strains of S. aureus and E. coli was consistently high, as indicated by geometric mean SBTs of at least 1:5 at 24 hours. Against β-lactamase-producing (β-LP) S. aureus, the geometric mean SBTs for A-S were at least 1:25 throughout the study period, while the geometric mean SBTs for T-C decreased over 24 hours from 1:29 to 1:6. Against β-LP E. coli, the bactericidal activities for both A-S and T-C were poor, with geometric mean peak SBTs of only 1:6 and 1:3, respectively. The geometric mean SBT for T-C against this E. coli strain had declined to 1:1 at 6 hrs. Conclusion . Increasing the dosing interval for T-C in patients with end-stage renal disease may lead to periods of insufficient clavulanic acid to protect ticarcillin from β-lactamase degradation.