A study of metabolites isolated from the urine samples of cats and dogs administered orbifloxacin

Urine samples of cats and dogs collected for 24 hr after a subcutaneous injection of orbifloxacin (OBFX) were analyzed. The metabolites were examined using HPLC. In the dog urine, 87% of total was the parent compound and 13% glucuronide compound of OBFX and 96% was parent and 4% metabolite in the cat urine. The metabolite of cat urine was identified as N-hydroxy OBFX, determined by comparison of the extraction of urine with chloroform with the standard compound of N-hydroxy OBFX, using LC/APCIMS. N-hydroxy OBFX had a weaker antibacterial activity against fluoroquinolone sensitive bacteria than the parent compound.     

Studies on the metabolites of tetramethylpyrazine in human urine

Tetramethylpyrazine (TMP), an active ingredient in Chuanxiong (Ligusticum Wallich Franch), a traditional Chinese herb, has been widely used especially in the treatment of patients with cerebral ischemic diseases in China. TMP was reported to have a short half-life time because of its rapid metabolism in the liver. In this paper we studied its metabolites in human urine with GC/MS after oral administration of TMP. Three metabolites were found in the water soluble acidic fraction of the urine and the main metabolite was identified to be 3,.5,6-trimethylpyrazinecarboxylic acid.     

Identification of two urine metabolites of vinyl chloride by GC-MS-investigations

A study of the effects of abrupt weaning on the very young pig showed that the samll intestine undergoes an acute inflammatory response and a reduction in plasma cell population by weaning day +7 or +8, in the absence of severe scours and abnormal proliferation by intestinal coliform bacteria. It is suggested that these changes may be common progenitors of nutritional and bacterial scours, and that they are due in part to increased metabolic activity of the "normal" microflora.     

Letter from Reykjavik

BACKGROUND AND OBJECTIVES: In previous manometric investigations, we observed that patients with chest pain and arterial hypertension frequently tend to display oesophageal motility abnormalities. Therefore, we set out to study this systematically. METHODS: Patients with chest pain and normal coronary angiogram (n=40) and healthy controls (n=20) were studied prospectively in a standardized fashion using a portable oesophageal manometry and blood pressure registration system over 24 hours. RESULTS: Twenty patients exhibited increased arterial blood pressure (24 h median > 135/85 mmHg), while in the other 20 patients and all controls the 24 h blood pressure patterns were normal. Median pressure amplitudes in the distal oesophagus were 46.5, 33 and 27 mmHg in patients with or without arterial hypertension and controls, respectively, and 30, 27 and 27 mmHg in the proximal oesophagus, respectively. The durations of distal contractions were 3.9, 3.4 and 3.4 s, respectively, and those of proximal contractions were 3.2, 3.0 and 3.2 s, respectively. Percentages of propulsive contractions were 53%, 44% and 59%, respectively, and those of simultaneous contractions were 23%, 25% and 10%, respectively. CONCLUSIONS: Patients and controls differ significantly regarding their oesophageal motility patterns. Patients without arterial hypertension exhibit impaired propulsion of oesophageal contractions, whereas patients with arterial hypertension tend to produce oesophageal hypermotility. This suggests that, depending on the presence or absence of arterial hypertension, different pathomechanisms of oesophageal motility disturbances come into play.     

Methylprednisolone-hemisuccinate and its metabolites in serum, urine and bile from two patients with acute graft rejection

A cross-sectional assessment of differences in social class and other sociodemographic variables at hospital admission for patients with psychotic disorders was carried out through a systematic survey of psychotic patients admitted to greater Baltimore psychiatric facilities between 1983 and 1989. Female patients, first-admission patients, and patients with bipolar disorder or other, nonschizophrenic psychosis were more likely to have been admitted to community, university, and private hospitals than to state hospitals. Patients in medium and higher social class categories were 1.29 to 2.57 times more likely to be admitted to community, university, and private hospitals than to state hospitals.     

Irinotecan (CPT-11) metabolites in human bile and urine

A female patient was treated with irinotecan (CPT-11) for liver metastatic colon carcinoma. She had a percutaneous biliary catheter because of extrahepatic biliary obstruction. The patient was treated with CPT-11 for three courses at doses of 350 mg/m2 for the first course and 300 mg/m2 for the remaining courses, given as a 30-min i. v. infusion. Metabolism studies in bile and urine were performed by coupling high-performance liquid chromatography to electrospray mass spectrometry. Conventional spectra [liquid chromatography/mass spectrometry (LC/MS)] allowed on-line molecular mass determination of CPT-11 and its main metabolites, whereas structural information was obtained by tandem mass spectrometry (LC/MS/MS). At least 16 metabolites were detected in bile, while 8 of them were also detected in urine. Three compounds were identified as the parent drug, the active metabolite 7-ethyl-10-hydroxycamptothecin (SN-38), and SN-38 glucuronide. The major metabolic pathway consists in oxidations of the terminal piperidine ring of the CPT-11 side chain, which eventually results in the formation of a primary amine. Other metabolites result from oxidation of the camptothecin nucleus. Finally, decarboxylation of the carboxylate form of CPT-11 was also observed. Several metabolites result from combinations of these pathways. The structures of the identified metabolites indicate for the first time a major role of monooxygenases in the elimination of a camptothecin derivative in humans. This finding will allow better understanding of interindividual variability in pharmacokinetics and intestinal toxicity of CPT-11.     

Letter from America: a time for reflection

Indwelling urethral catheters are the most common cause of urinary tract infections (UTI), yet there is no direct evidence that technique of catheter insertion affects this. In a prospective study, 156 patients underwent preoperative urethral catheterisation, randomly allocated to 'sterile' or 'clean/non-sterile' technique groups. There was no statistical difference between the two groups with respect to the incidence of UTI. There was a considerable cost difference between the two groups, the 'sterile' method being over twice as expensive as the 'clean' method. Strict sterility is not necessary in preoperative short-term urethral catheterisation and is more expensive and time consuming.