Colorectal serrated pathway cancers and precursors

The serrated pathway (SP) can be viewed as two parallel, but partially overlapping, arrays of colorectal precursor lesions, and their respective endpoint carcinomas, that are distinct from those of the conventional adenoma–carcinoma sequence (APC‐pathway). In this review we focus at the outset on the clinical impact, pathological features, molecular genetics and biological behaviours of the various SP cancers. Then we summarize the clinicopathological features, classification and molecular profiles of the two main precursor lesions that anchor the respective pathways: (i) sessile serrated adenoma/polyp (SSA/P), also called sessile serrated lesion (SSL), and (ii) traditional serrated adenoma (TSA). Activating mutations of the RAS–RAF–MAPK pathway initiate and sustain the lesions of the SP, and CpG island methylation of the promoter regions of tumour suppressor and DNA repair genes play the major role in their neoplastic progression. The SP includes microsatellite stable (MSS) carcinomas that are among the most biologically aggressive colorectal carcinomas (CRC), and also accounts for the great preponderance of sporadic hypermutated, mismatch repair (MMR)‐deficient or microsatellite instable (MSI) CRC. The identification, removal and appropriate classification of at‐risk SP precursors and surveillance of individuals who harbour these lesions present a challenge and opportunity for CRC prevention and mortality reduction.     

Research on medication use in the neonatal intensive care unit

Introduction: Research on medication use aims at assessing how much of current pharmacotherapy is rational. In neonates, this is hampered by extensive off-label drug use and limited knowledge.

Areas covered: We report on medication use research and have conducted a systematic review of observational studies on medication use to provide an updated overview on characteristics, objectives, methods, and patterns in hospitalized neonates. Moreover, a review on aspects of medication use for opioids, anti-epileptics, gastric acid-related disorders and respiratory stimulants with emphasis on trends and impact of interventions is presented, illustrating how research on medication use can contribute to improved neonatal pharmacotherapy and more focused research. Medication use reports describe patterns and provide signals on irrational use, benchmarking, or can guide research priorities. Moreover, this may generate information on how neonatal health topics and their pharmacotherapy are handled over time or across regions.

Expert opinion: Research on medicine utilization is relevant, since it will inform us on aspects like trends, variability, or about the impact and pattern of implementation of guidelines in neonates. Further progress necessitates to merge datasets on medication use with clinical characteristics, and perinatal drug use remains an area in need of additional research.     

Emergencies caused by pheochromocytoma, neuroblastoma, or ganglioneuroma.

Pheochromocytoma may lead to important emergency situations, ranging from cardiovascular emergencies to acute abdomen and multiorgan failure. It is vital to think about this disease in any emergency situation when conventional therapy fails to achieve control or symptoms occur that do not fit the initial diagnosis. The importance of keeping this diagnosis in minds is underscored by the fact that, in 50% of pheochromocytoma patients, the diagnosis is initially overlooked. Two other tumors of the sympathetic nervous system, neuroblastoma and ganglioneuroma, are less commonly associated with emergency conditions. If they occur, they are often linked to catecholamine excess, paraneoplastic phenomena, or local tumor mass effect.     

Cytochrome P450 3A4 and P-glycoprotein Activity and Assimilation of Tacrolimus in Transplant Patients with Persistent Diarrhea

Renal transplant recipients suffering from persistent diarrhea have been repeatedly reported to have increased tacrolimus (Tac) trough levels. This study aimed to explore this phenomenon in detail in 15 renal transplant recipients with diarrhea, whose immunosuppression consisted of corticosteroids, mofetil mycophenolate and Tac. Both hepatic and intestinal CYP3A4 and PGP activity, important determinants of Tac bioavailability, were assessed, together with global CYP activity and investigations for gastrointestinal infection, function and morphology. Global CYP, CYP3A4, PGP and trough/dose levels of Tac were compared with diarrhea-free controls. In addition, a pharmacokinetic study of Tac was performed in 11 patients affected by diarrhea versus 9 controls. As expected, diarrhea was associated with increased Tac trough levels. An even stronger, significant increase of dose-normalized Tac levels was observed between 90 and 360 min after Tac intake. Time to peak concentration and drug half-life, however, were not altered. In addition, a concomitant decrease (+/-50%) of intestinal PGP activity was noticed in patients with diarrhea. For global CYP, CYP3A4 and hepatic PGP activity no such differences were noted. This pattern was not influenced by the specific cause of diarrhea. These data strongly suggest that persistent diarrhea is associated with an increased oral bioavailability of Tac.