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At least 19 recordsLinked to original sources
PubMed1984

Preclinical pharmacokinetics of benznidazole.

Benznidazole is a lipophilic analogue of misonidazole (MISO) which shows promise as a chemosensitizer for clinical use, particularly in combination with CCNU. We have investigated the detailed pharmacokinetics of benznidazole in mice, dogs and sheep to provide a data base for the estimation of doses required for chemosensitization in man. Pharmacokinetic behaviour was linear except at high doses in mice. Absorption was fairly rapid and bioavailability was complete following both i.p. administration in mice and oral administration in dogs. Elimination t1/2 values were longer than for MISO, being 90 min in mice, 4-5 h in sheep and 9-11 h in dogs. At doses giving linear kinetics, peak whole plasma concentrations per administered mg kg-1 were 0.75 micrograms ml-1 for the i.p. route in mice and 1.8 micrograms ml-1 for the oral route in dogs. Though between 39 and 59% of plasma benznidazole was bound to protein, tissue penetration was generally good. Tissue/whole plasma ratios ranged from 59-99% for transplantable mouse tumours and from 14-70% for spontaneous dog neoplasms. Nervous tissue penetration was similar to that in tumours: brain/whole plasma ratios averaged between 61 and 76% in mice and 42% in dogs, while peripheral nerve/whole plasma ratios in dogs averaged 74%. Mean liver/whole plasma ratios were 42% and 71% in BALB/c and C3H/He mouse strains respectively. Only approximately 5% of the administered dose was excreted unchanged in the urine, indicating the likelihood of extensive metabolism. These data show that benznidazole should have suitable pharmacokinetic properties for clinical use as a chemosensitizer. Enhancement of CCNU response is likely to require circulating benznidazole concentrations of 10-30 micrograms ml-1 and we predict that these will be obtained with oral doses of 6-20 mg kg-1 in man.

Animals↗
PubMed1964

PATHOLOGY OF TUMOURS IN CHILDREN.

An analysis of the types of tumour in children in the Manchester hospital region indicates that approximately two-thirds arose in the reticuloendothelial or nervous systems. The high mortality is largely due to the nature or site of the tumours, the majority of which cannot be eradicated by purely local measures. The most likely means of causing any significant improvement would be by greater centralization in the treatment of these children.

Adolescent↗
PubMed1991

Malignant schwannoma associated with xeroderma pigmentosum in a patient belonging to complementation group D.

A 43-year-old man with xeroderma pigmentosum, XP97TO, was allocated to complementation group D. He had had moderate photosensitivity at age 1 year and freckles by age 6 but no neurologic abnormalities. Nevertheless, his fibroblasts in culture had the XP-D phenotype. They showed a sevenfold hypersensitivity to killing by 254 nm ultraviolet radiation and a diminished level (29%) of unscheduled DNA synthesis. Phototesting revealed delayed maximum erythema at 72 hours after UVB exposure and a lowered minimal erythema dose. Lentigo maligna developed on the patient's face, and a rapidly growing malignant schwannoma was found on the left trigeminal nerve. This may be the first case of a peripheral nervous tissue neoplasm in xeroderma pigmentosum.

Adult↗
PubMedDate not supplied

[Comparative study of the activity of arginase isoenzymes in brain tumors of humans and experimental animals].

Isoenzyme spectrum and total activity of arginase were studied in rat brain during growth of transplanted neurinoma and glioma as well as in malignant tissues of human brain. After transplantation of the tumors two peaks of arginase activation were observed within 2-4 days in rat brain tissues and within 16 days in tumoral tissue. Positively charged isoenzyme I of arginase was mainly activated but activity of neutral isoenzyme II was unaltered or slightly decreased. In human brain tumors activity of isoenzyme I was also prevailed, while activity of isoenzyme II was increased in some cases. Regulation of the arginase activity appears to occur by a complex mechanism and the enzyme plays a key role in development of nervous tissue neoplasms.

Animals↗