Identification of urinary metabolites of 2,4,6-trinitrotoluene in rats by liquid chromatography-mass spectometry

Metabolites of 2,4,6-trinitrotoluene (TNT) were found in the urine of rats fed with TNT. The urine extracts were analysed by liquid chromatography-mass spectrometry (LC-MS). Metabolites found included TNT itself as well as 2-amino-4,6-dinitrotoluene, 4-amino-2,6-dinitrotoluene and 2,4-diamino-6-nitrotoluene, indicating that reduction processes are responsible for the formation of these metabolites.     

Kr-81m ventilation imaging: clinical utility in suspected pulmonary embolism

The results of Kr-81m/Tc-99m ventilation-perfusion (VP) lung scintigraphy were correlated with the results of pulmonary angiography for 74 patients suspected of having pulmonary embolism (PE). Among patients having a diagnostic scan, the sensitivity and specificity of scintigraphy were 91% and 94%, respectively. Also, 157 consecutive cases of Kr-81m/Tc-99m VP lung scintigraphy were reviewed, and the frequency of an indeterminate scan was found to be 22%. A similar frequency was found for VP scintigraphy with xenon-133. Of eight patients who had indeterminate scans due to the presence of a single VP mismatch, four were demonstrated to have PE by angiography. Kr-81m is an excellent agent for VP scanning in cases of suspected PE, offering accuracy in diagnosis as well as favorable physical properties.     

Kinetics of the tissue distributions of sulindac and metabolites. Relevance to sites and rates of bioactivation

Sulindac (sulfoxide) is a prodrug in reversible metabolic equilibrium with its pharmacologically active metabolite, the corresponding sulfide. Following simultaneous parenteral injection of sulfoxide-14C and sulfide-3H at equivalent dosage, all labeled species in the plasma of rats and guinea pigs and in representative tissues were determined at various times. Rate constants for sulfoxide in equilibrium or formed from sulfide, calculated from the rates of interchange of the two labels in plasma, are still higher than those approximated from earlier, single-label studies, and indicate turnovers of total body pools every 45 and 8.5 min in rat and guinea pig, respectively. From the time-course of tissue/plasma ratios of endogenous labeled species, it can be concluded that kidney and liver are major sites of bioactivation of the prodrug, with significant sulfoxide leads to sulfide activity present in all tissues examined. At steady state, tissue concentrations of each redox form are determined by the ratio of the metabolic rate constants for the two opposing biotransformations and by unique tissue/plasma distributive constants for each redox form, resulting in all tissues, except lung, and at all times examined, in a sulfide/sulfoxide ratio greater than one.     

Cholelithiasis in Singapore: Part II A clinical study

In the present study of 241 patients submitted for gallbladder and biliary tract surgery, it is found that choledocholithiasis in cases in Singapore presents with a wide spectrum of clinical manifestations. It is essential that the less common clinical presentations should be recognized.     

Characterization of monoaminergic terminals in the neostriatum of neonatal rats: an electron microscopic morphometric analysis

Monoaminergic (MA) boutons in the neostriatum of neonatal rats were studied by using 5-hydroxydopamine. We found: (a) bouton size averaged 0.6 micron in diameter; (b) terminal density was 68 boutons per 7200 micron2 area; (c) synaptic frequency was 33.2%; and (d) MA neurons constituted 9.2% of all boutons. This population was much lower than that reported in immature neocortex where MA neurons are a major innervation.     

Comparison between polymerase chain reaction and fungal culture for the detection of fungi in patients with chronic sinusitis and normal controls

CONCLUSION: PCR using panfungal gene primers is a more sensitive method for fungus detection than fungus culture, both in patients with chronic sinusitis and in normal controls. The presence of fungi alone, however, was insufficient to implicate them as pathogens in chronic sinusitis. OBJECTIVE: Previous findings have suggested that polymerase chain reaction (PCR)-based methods are more sensitive and reliable than conventional culture methods for the detection of fungal DNA. We therefore compared these methods in 82 patients with chronic sinusitis and 40 normal controls. MATERIAL AND METHODS: The noses of the subjects were irrigated with sterile saline, and the samples collected. The sediment from each irrigation was used for fungus culture and PCR analysis. RESULTS: PCR analysis using panfungal gene primers showed that 76/82 (92.5%) patients with chronic sinusitis and 39/40 (97.5%) normal controls were positive. In contrast, fungus cultures were positive in 19/82 (23.2%) patients with chronic sinusitis and 12/40 (30.0%) normal controls. We observed no significant between-group differences in the prevalence of fungus or in the fungal species detected.     

Splenic abscess associated with endocarditis in a patient on hemodialysis: a case report

Splenic abscess is an unusual condition usually seen in immunocompromised patients or associated with intravenous drug abuses. Several conditions including trauma, immunodeficiency, corticosteroid and/or immunosuppressive therapy and diabetes mellitus have been listed under the predisposing factors for a splenic abscess. Splenic abscess in a patient on hemodialysis is a rare but life-threatening condition if not corrected. We describe a case of splenic abscess with bacterial endocarditis on maintenance hemodialysis. He had staphylococcal septicemia secondary to bacterial endocarditis at the mitral valve from the dialysis access-site infection. Although hematologic seeding from endocarditis has been the predisposing factor for splenic abscess, we postulate that access-site infections may predispose hemodialysis patients to splenic abscess. Splenic abscess may be considered as one of the causes when patients on hemodialysis develop unexplained fever.     

Pharmacokinetics of glutathione and its metabolites in normal subjects

To determine the loading and maintenance dosage of glutathione (GSH) for patients suffering from reactive oxygen species (ROS) injury such as acute paraquat intoxication, a kinetic study of reduced GSH was performed in synchrony with that of cysteine (Cys), cystine (Cys2), and methionine (Met). Human subject's porticipitation was voluntary. The effective dose of Cys, Cys2, and Met against ROS in fibroblast cells generated by paraquat was assessed using laser scanning confocal microscopy. Both Cys and Met suppressed ROS in a dose-dependent manner at concentrations of 1-1,000 microM; the concentration required to suppress ROS by 50% was 10 microM for Cys and 50 microM for Met. Using metabolite kinetics with the assumption that Cys and Met are the metabolites of GSH, expected concentrations of Cys and Met of above 20 and 50 microM were estimated when GSH was administered at 50 mg/kg body weights every 205.4 min for Cys and 427.4 min for Met.