Patient-derived xenografts as tools in pharmaceutical development

Successful drug development in oncology is grossly suboptimal, manifested by the very low percentage of new agents being developed that ultimately succeed in clinical approval. This poor success is in part due to the inability of standard cell-line xenograft models to accurately predict clinical success and to tailor chemotherapy specifically to a group of patients more likely to benefit from the therapy. Patient-derived xenografts (PDXs) maintain the histopathological architecture and molecular features of human tumors, and offer a potential solution to maximize drug development success and ultimately generate better outcomes for patients. Although imperfect in mimicking all aspects of human cancer, PDXs are a more predictable platform for preclinical evaluation of treatment effect and in selected cases can guide therapeutic decision making in the clinic. This article summarizes the current status of PDX models, challenges associated with modeling human cancer, and various approaches that have been applied to overcome these challenges and improve the clinical relevance of PDX cancer models.

Enuresis in hyperthyroidism: a temporary lack of central control mechanism leads to nocturnal enuresis

We report on a 9-year-old boy who suffered from hyperthyroidism and a new appearance of enuresis. Bedwetting ceased and prepulse inhibition (PPI) - measured as a parameter of central control - increased during the course of therapy.

CONCLUSION

The increase in PPI is an indication that enuresis in hyperthyroidism could be as a result of a temporary loss of central control on brainstem reflexes. The case conveys new insights into the correlation between thyroid hormones and micturition patterns and the aetiology of enuresis.

Congenital adrenal hyperplasia diagnosed in a middle-aged woman

Short stature, severe hirsutism, an enlarged clitoris and lack of vaginal introitus were manifest in a 55-year-old female karyotype, male phenotype patient brough up as a female. The hormone profile suggested congenital adrenal hyperplasia due to 21-hydroxylase adrenal enzyme deficiency. Follicle-stimulating hormone and luteinizing hormone levels were 122.5 and 100.3 mIU/ml, respectively, within the normal range for a postmenopausal woman. Computerized axial tomography revealed a large cystic tumor connected to the right adrenal gland. Both the right adrenal gland and the cyst were removed. The adrenal cortex showed diffuse hyperplasia and contained a well-defined nodule. The case was interesting because we had the opportunity of examining a patient of advanced age with untreated congenital adrenal hyperplasia and because of the very rare combination of adrenogenital syndrome with nodular hyperplasia and a cystic tumor, which was most probably a degenerated adenoma.

Unusual complications of subclavian catheterization

Infraclavicular subclavian vein catheterization is still a well accepted technique both in operating rooms and intensive care units. Two unusual complications are described: delayed intrathoracic haematoma and severe mediastinal emphysema needing prolonged treatment. The case reports are presented and the complications discussed. The necessity for routine chest x-ray post-operative catheterization and the danger of multiple attempts are stressed.