Introduction: Hepatoblastoma (HB) is the most common primary malignant liver neoplasm in children. Its increasing survival rate is related to the progress in modern imaging, surgical techniques, and new chemotherapy regimens. Clinical approach: One of the past achievements was the development of the pretreatment extension of disease (PRETEXT) system. Gradually, the HB therapeutic approach has become more individualized with better stratification of patients. Controversies: These include the need for preoperative chemotherapy and its optimal duration; intensity of preoperative chemotherapy required for locally advanced cases (PRETEXT 4); optimal surgical treatment for locally advanced tumors: aggressive hepatic resections versus liver transplantation; the role of postoperative chemotherapy in the post-transplant setting; the timing and role of metastasectomy in patients with disseminated disease who undergo partial liver resection; and the prognostic significance of several HB pathology variants. Hepatoblastoma biology: Beta-catenin mutations and the beta-catenin/Wnt pathway play an important role in HB development. There have been at least two molecular signatures in HB published. Unluckily, all of these findings are based on relatively small clinical series and require confirmation. Conclusion: The treatment of HB started from one and the same therapy for all patients and aimed at increased treatment individualization, but the future seems to lie in biology-driven patient-tailored therapies.

Failed back surgery syndrome (FBSS) is complex and recurrent chronic pain after spinal surgery. Several important patient and surgery related risk factors play roles in development of FBSS. Inadequate selection of the candidates for the spinal surgeries is one of the most crucial causes. The guidelines suggest that conservative management featuring pharmacologic approaches and rehabilitation should be introduced first. For therapy-refractory FBSS, spinal cord stimulation (SCS) is recommended in selected patients. Treatment efficacy for FBSS has increased over the years with the majority of patients experiencing pain relief and reduced medicinal load. Improved quality of life can also be achieved using SCS. Cost-effectiveness of SCS still remains unclear. However evidence for SCS role in FBSS is controversial, SCS can be beneficial for carefully classified patients.

Object: The aim of our study was to evaluate and compare the effects of physical exercise interventions on physical fitness and executive functions in children. Methods: Six-year-old children participated in the study and were randomly divided into physical exercise group (PE group, n = 43) and control group (C group, n = 46). The children in the PE group participated in a physical exercise program for 45 min daily, four days a week for 11 weeks. The children in the C group continued with their usual routines. Then, all the children were tested before and after the experiment for body composition (height, weight, BMI), physical fitness (20-m shuttle run test, standing long jump test, grip strength test, 4 × 10 m shuttle run test and sit and reach tests), and executive functions test (animal go/no-go task, working memory span task, simple reaction test and flexible item selection task) before and after the 11-week period. Results: The 11 weeks of physical exercise did not significantly affect the body composition of the children (p > 0.05). The physical fitness and executive functions test results showed that 11 weeks of physical exercise interventions improves physical fitness (cardiopulmonary fitness, muscle strength, speed sensitivity and flexibility quality) and executive functions parameters (inhibitory control, working memory, the reaction time, and cognitive flexibility) in children (p < 0.05, p < 0.01). Conclusion: 11 weeks of physical exercise can improve the physical fitness and executive functions of six-year-old children.

Background/Aims: This retrospective study analysed hypertension management and adherence to blood pressure (BP) targets among renal transplant recipients (RTRs) under specialized care in the Outpatient Transplantation Unit in the Department of Nephrology, Transplantology and Internal Medicine at Gdansk University Hospital. Methods: Medical records of 101, 316, 639 and 818 RTRs diagnosed with hypertension, who received outpatient care in 2001, 2006, 2011 and 2014, respectively were analysed in four independent cross-sectional surveys. All RTRs received antihypertensive regimens. Results: The overall most commonly used antihypertensive agents were beta-blockers (BB) (range 66.3-82.5%) followed by calcium channel blockers (CCB) (range 52.8-64.2%). Whilst a significant, upward tendency of BB usage (p<0.01) was observed, CCB usage (p<0.001) displayed a downward tendency as a first line therapy in the subsequent years. The average number of antihypertensive agents used per patient increased significantly from 2.24±1.03 in 2001 to 2.55±1.25 in 2014 (p<0.05). The most frequently used combination of hypotensive therapy consisted of two or three antihypertensive drugs depending on the survey. The most common two drug combination consisted of BB and CCB followed by BB accompanied by angiotensin converting enzyme inhibitors. A significant, upward tendency in the use of four (p<0.001) and five (p<0.05) antihypertensive drugs simultaneously, was observed in subsequent years. The target values of BP i.e. <140/90 mmHg were accomplished in 47, 58, 60 and 46% of RTRs in subsequent years. In a secondary - stratified analysis of data from 2014, younger patients (p<0.05), patients with better graft function (p<0.001), patients treated with a higher number of antihypertensive agents (p<0.001) and those not treated with BB (p<0.01) were shown to reach the BP target of below 140/90 mmHg more often. Conclusion: The study showed intensification of hypertension treatment in RTRs in subsequent years with BB assuming a dominant role.

Introduction: Rare diseases are becoming increasingly recognized worldwide as an important public health challenge and Orphan Drugs begin to play an important role in Research and Development. There are several major issues concerning conducting clinical trials in the field of Rare Diseases, especially in children, as 80% of those diseases are genetic in origin and involve, in most instances, children. Areas covered: This review concentrates on challenges associated with the patient recruitment process. The authors experience and opinion was complemented by a systematic search of relevant literature and includes ethical, cultural and geographical issues with rare diseases. The review presents current opinion and provides valuable support for planning and conducting clinical research in rare diseases. Expert opinion: The expert opinion section concentrates on importance of future rare disease clinical research in the context of understanding common diseases and developing new treatment options.