Occupational Contamination with a Highly Enriched Uranium Solution.

This medical case report describes the first reported instance of occupational skin contamination with a uranyl nitrate solution containing highly enriched uranium. The report provides an overview of the unique medical treatment and management considerations in such a case. Internal dose assessment is covered in detail. The discussion covers key points regarding uranium characteristics, chemical and radiological damage to body tissues from HEU exposure, and resources available for assistance with a case of radiological contamination. This information adds to the limited medical literature on this topic and provides a valuable reference for medical personnel when dealing with this uncommon problem.

Comparative efficacies of levofloxacin and ciprofloxacin against Streptococcus pneumoniae in a mouse model of experimental septicaemia.

The in vivo efficacies of levofloxacin and ciprofloxacin were compared against three clinical isolates of Streptococcus pneumoniae, using a mouse protection model. Two strains (SP 22 and SP 28) were penicillin-sensitive while one strain (SP 46) was penicillin-resistant. Each strain had identical susceptibility to both drugs. Using mice with renal impairment induced by uranyl nitrate injection, the elimination half-life of each antibiotic was prolonged to approximate human pharmacokinetic profiles of the drugs. The dosing regimen of each drug that yielded serum levels in mice which mimic human therapeutic concentrations of the drugs, were designed. One hour after intraperitoneal inoculation with minimum lethal dose of each strain, either levofloxacin at a dosing regimen of 10.6 mg/kg every 8 h or ciprofloxacin at 9.5 mg/kg every 8 h was subcutaneously administered for a total of six or 15 doses. In treatment, monitored daily for 5-8 days, levofloxacin resulted in higher survival compared with ciprofloxacin for the three strains. For example, percent survival following levofloxacin treatment recorded at day 4 postinfection with SP 22, SP 28 and SP 46 were 41, 90 and 30%, respectively, while the corresponding values after ciprofloxacin treatment were 27, 75 and 16%, respectively. However, statistical analysis did not reveal a significant difference (p > 0.05). The lack of significant difference observed in the efficacies of both drugs reflected the comparability of their 24-h AUC/MIC ratios. It is suggested that, with some strains of S. pneumoniae, the efficacy of levofloxacin may be equivalent to that of ciprofloxacin in the treatment of systemic pneumococcal infections caused by susceptible strains of the organism.

Glycine prevents toxic tubular cell injury.

Glycine prevents tubular injury as suggested by in vitro cell culture studies, studies in the isolated perfused kidney, and in vivo studies. We have previously demonstrated that intratubular administration of uranyl nitrate (UN) produces proximal tubular cell injury and decreases proximal tubular reabsorption (APR). The decrease in APR activates tubuloglomerular feedback and lowers nephron filtration rate (SNGFR). This study was designed to evaluate if glycine administration could prevent the decrease in SNGFR after UN administration and if maintenance of SNGFR was due to tubular cell cytoprotection or suppression of the tubuloglomerular feedback. Administration of 0.65 ng of UN into the early proximal tubule was associated with a decrease in distal SNGFR (SNGFRD) from 29 +/- 2 to 24 +/- 2 nL/min (p < .05) and late proximal SNGFR (SNGFRLP) from 37 +/- 2 to 26 +/- 2 nL/min, and APR from 14 +/- 1 to 10 +/- 1 nL/min. Systemic administration of glycine (20 g/dL, 1.4 mL/h) was associated with significant increases in SNGFRD and SNGFRLP, and APR (38 +/- 3, 44 +/- 3, and 15 +/- 2 nL/min). UN administration did not affect APR or SNGFR in glycine-treated rats. These findings demonstrate that glycine prevents UN-induced decreases in SNGFR through a cytoprotective effect on proximal tubular cells.

Intrarenal haemodynamics in uranyl nitrate-induced acute renal failure.

Intrarenal haemodynamics were investigated in the dog at various intervals after the iv. injection of 10 mg/kg uranyl nitrate (UN). Renal blood flow (RBF), as determined by measuring the renal venous effluent and by radioactive microspheres, decreased by about 23% at 6 hr after UN administration, as compared to normal controls, then rose and reached controls at 24 to 48 hr; subsequently, RBF increased and surpassed controls by about 36% at 96 hr. Thus, the early phase (6 hr) and the late phase (96 hr) of uranyl nitrate-induced acute renal failure (UNARF) were characterized by an increase and by a decrease, respectively, in overall renal vascular resistance. Glomerular filtration rate (GFR) diminished to about 37% of controls at 6 hr, with no change in urinary output (V). In the following hours, however, GFR and V fell quickly and reached practically zero at 12 to 24 hr. Approximate calculations revealed a predominantly preglomerular vasoconstriction in the early phase and post-glomerular vasodilatation in the late phase. Radioactive microspheres showed a nearly proportionate decrease in perfusion of all cortical layers in the early phase (6 hr); in the late phase (96 hr), however, blood flow to the outermost layer remained unaltered, while perfusion of the inner cortical and juxtamedullary layers increased significantly.

Renal glomerular and tubular lesions in rabbits treated with uranyl nitrate.

Renal injury and regeneration was followed light--and electron microscopically in rabbits treated with uranyl nitrate. The presence and importance of glomerular lesions is noteworthy.