Combined salvage therapies for recurrent glioblastoma multiforme: evaluation of an interdisciplinary treatment algorithm

Glioblastoma multiforme patients presenting with recurrence following multimodality therapy have limited palliative treatment options when the major modalities of therapy including surgery, radiochemotherapy and adjuvant chemotherapy have been exhausted. The authors introduce a clinical and radiological indication-solving algorithm and provide outcome rates of a glioblastoma recurrence cohort. Sixty six consecutive adult patients with recurrent glioblastoma who underwent a combined scheme of salvage treatments consisting of reoperation, high dose rate (HDR) brachytherapy and chemotherapy were included in this prospective study and were compared to a historical control group of 24 recurrent glioblastoma patients who have been treated with intensive temozolomide chemotherapy as the only treatment modality. Median follow-up was 32 months (range 28–36 months). Median survival was 9 months for the entire cohort after salvage treatment and can be translated into a 3-month improvement in survival compared to the control group of patients with glioblastoma recurrence treated with temozolomide alone (P = 0.043). Toxicity and adverse events of reoperation, HDR brachytherapy combined with chemotherapy were quite favourable compared to intensive temomozolomide chemotherapy as the only treatment. Our experience suggests that a combined salvage treatment plan appears to be both feasible and effective and can be considered in selected patients affected by recurrent high grade gliomas. The authors’ clinical and radiological indication-solving algorithm may assist in providing the best possible salvage treatment for this difficult population.     

Vein graft disease in a knockout mouse model of hyperhomocysteinaemia

A major reason for vein graft failure after coronary artery bypass grafting is neointimal hyperplasia and thrombosis. Elevated serum levels of homocysteine (Hcy) are associated with higher incidence of cardiovascular disease, but homocysteine levels also tend to increase during the first weeks or months after cardiac surgery. To investigate this further, C57BL/6J mice (WT) and cystathionine‐beta‐synthase heterozygous knockout mice (CBS+/?), a mouse model for hyperhomocysteinaemia, underwent interposition of the vena cava of donor mice into the carotid artery of recipient mice. Two experimental groups were examined: 20 mice of each group underwent bypass surgery (group 1: WT donor and WT recipient; group 2: CBS+/? donor and CBS+/? recipient). After 4 weeks, the veins were harvested, dehydrated, paraffin‐embedded, stained and analysed by histomorphology and immunohistochemistry. Additionally, serum Hcy levels in CBS knockout animals and in WT animals before and after bypass surgery were measured. At 4 weeks postoperatively, group 2 mice showed a higher percentage of thrombosis compared to controls, a threefold increase in neointima formation, higher general vascularization, a lower percentage of elastic fibres with shortage and fragmentation in the neointima, a lower percentage of acid mucopolysaccharides in the neointima and a more intense fibrosis in the neointima and media. In conclusion, hyperhomocysteinaemic cystathionine‐beta‐synthase knockout mice can play an important role in the study of mechanisms of vein graft failure. But further in vitro and in vivo studies are necessary to answer the question whether or not homocysteine itself or a related metabolic factor is the key aetiologic agent for accelerated vein graft disease.     

Combining the ‘bottom up’ and ‘top down’ approaches in pharmacokinetic modelling: fitting PBPK models to observed clinical data

Pharmacokinetic models range from being entirely exploratory and empirical, to semi-mechanistic and ultimately complex physiologically based pharmacokinetic (PBPK) models. This choice is conditional on the modelling purpose as well as the amount and quality of the available data. The main advantage of PBPK models is that they can be used to extrapolate outside the studied population and experimental conditions. The trade-off for this advantage is a complex system of differential equations with a considerable number of model parameters. When these parameters cannot be informed from in vitro or in silico experiments they are usually optimized with respect to observed clinical data. Parameter estimation in complex models is a challenging task associated with many methodological issues which are discussed here with specific recommendations. Concepts such as structural and practical identifiability are described with regards to PBPK modelling and the value of experimental design and sensitivity analyses is sketched out. Parameter estimation approaches are discussed, while we also highlight the importance of not neglecting the covariance structure between model parameters and the uncertainty and population variability that is associated with them. Finally the possibility of using model order reduction techniques and minimal semi-mechanistic models that retain the physiological-mechanistic nature only in the parts of the model which are relevant to the desired modelling purpose is emphasized. Careful attention to all the above issues allows us to integrate successfully information from in vitro or in silico experiments together with information deriving from observed clinical data and develop mechanistically sound models with clinical relevance.     

Transthoracic Repair of Asymptomatic Morgagni Hernia in an Adult

Morgagni hernia represents a rare type of diaphragmatic hernia which usually occurs on the right side, in the anterior mediastinum. Predisposing factors of Morgagni hernia include pregnancy, obesity or other causes of increased intraabdominal pressure, and a history of trauma. Most of adults diagnosed with a foramen of Morgagni are asymptomatic. We report a case of an overweight 23-year-old asymptomatic patient with a Morgagni hernia incidentally diagnosed on chest x-ray. There was a satisfactory result after the repair by a transthoracic approach.