Theoretical model for laser ablation outcome predictions in brain: calibration and validation on clinical MR thermometry images

Purpose: Neurosurgical laser ablation is experiencing a renaissance. Computational tools for ablation planning aim to further improve the intervention. Here, global optimisation and inverse problems are demonstrated to train a model that predicts maximum laser ablation extent.

Methods: A closed-form steady state model is trained on and then subsequently compared to N?=?20 retrospective clinical MR thermometry datasets. Dice similarity coefficient (DSC) is calculated to provide a measure of region overlap between the 57?°C isotherms of the thermometry data and the model-predicted ablation regions; 57?°C is a tissue death surrogate at thermal steady state. A global optimisation scheme samples the dominant model parameter sensitivities, blood perfusion (ω) and optical parameter (μ_eff) values, throughout a parameter space totalling 11?440 value-pairs. This represents a lookup table of μ_eff–ω pairs with the corresponding DSC value for each patient dataset. The μ_eff–ω pair with the maximum DSC calibrates the model parameters, maximising predictive value for each patient. Finally, leave-one-out cross-validation with global optimisation information trains the model on the entire clinical dataset, and compares against the model naïvely using literature values for ω and μ_eff.

Results: When using naïve literature values, the model’s mean DSC is 0.67 whereas the calibrated model produces 0.82 during cross-validation, an improvement of 0.15 in overlap with the patient data. The 95% confidence interval of the mean difference is 0.083–0.23 (p?Conclusions: During cross-validation, the calibrated model is superior to the naïve model as measured by DSC, with +22% mean prediction accuracy. Calibration empowers a relatively simple model to become more predictive.     

Efectividad de la técnica de resolución de problemas aplicada por enfermeras: disminución de la ansiedad y la depresión en cuidadoras familiares

ObjectiveTo determine the effectiveness of Problem Solving Technique in reducing anxiety and depression, and increased perceived well-being in women family caregivers of chronic patients.DesignA clinical trialField of studyHealth centres in Tarragona, Spain, during 2007-2011.ParticipantsA sample 122 caregivers of patients in home care programs that met the inclusion criteria, were assigned to intervention or control group according to a simple random process.InterventionsIn the experimental group, the nurses applied the Problem Solving Technique to the caregiver according to a four-session protocol. The nurses provided the usual care to the caregivers In the control group. One month after intervention, the dependent vriables were measured again in both groups.Principal measurementThe dependent variables of anxiety and depression were measured using the Goldberg scale, and the emotional well-being variable by the scale of emotional health of the primary caregiver.ResultsA statistically significant improvement was detected in the anxiety and depression symptoms, as well as the perceived well-being in the intervention group compared to the control group.ConclusionsImplementation of the Problem Solving Technique is a useful therapeutic tool for reducing symptoms of distress in family caregivers of chronic patients.     

Autophagy,mitochondria and 3-nitropropionic acid joined in the same model

Huntington''s disease (HD) is a neurodegenerative disorder caused by a mutation in the gene encoding the huntingtin protein. Although the precise mechanism by which neuronal degeneration occurs is still unclear, several elements are important to its development: (1) altered gene expression and protein synthesis, (2) mitochondrial damage and (3) improper regulation of the autophagy programme. In this issue of British Journal of Pharmacology, Galindo and co-workers provide the first evidence for a role of the mitochondrial permeability transition pore (mPTP) in mitochondrial fragmentation and autophagy activation. In a model of cell death induced by 3-nitropropionic acid (3-NP) in human neural cells, the authors describe clear functions for mPTP and Bax, but not the mitochondrial fusion/fission machinery, mitochondrial fragmentation and autophagy (mitophagy). This commentary summarises the significance of this relationship and suggests several points for future development.     

EAACI guidelines on allergen immunotherapy: Prevention of allergy

Allergic diseases are common and frequently coexist. Allergen immunotherapy (AIT) is a disease‐modifying treatment for IgE‐mediated allergic disease with effects beyond cessation of AIT that may include important preventive effects. The European Academy of Allergy and Clinical Immunology (EAACI) has developed a clinical practice guideline to provide evidence‐based recommendations for AIT for the prevention of (i) development of allergic comorbidities in those with established allergic diseases, (ii) development of first allergic condition, and (iii) allergic sensitization. This guideline has been developed using the Appraisal of Guidelines for Research & Evaluation (AGREE II) framework, which involved a multidisciplinary expert working group, a systematic review of the underpinning evidence, and external peer‐review of draft recommendations. Our key recommendation is that a 3‐year course of subcutaneous or sublingual AIT can be recommended for children and adolescents with moderate‐to‐severe allergic rhinitis (AR) triggered by grass/birch pollen allergy to prevent asthma for up to 2 years post‐AIT in addition to its sustained effect on AR symptoms and medication. Some trial data even suggest a preventive effect on asthma symptoms and medication more than 2 years post‐AIT. We need more evidence concerning AIT for prevention in individuals with AR triggered by house dust mites or other allergens and for the prevention of allergic sensitization, the first allergic disease, or for the prevention of allergic comorbidities in those with other allergic conditions. Evidence for the preventive potential of AIT as disease‐modifying treatment exists but there is an urgent need for more high‐quality clinical trials.     

Characterization of Recombinant Fluoroquinolone-Resistant Pneumococcus-Like Isolates

Fourteen fluoroquinolone-resistant streptococcal isolates with recombinant DNA topoisomerase genes, preliminarily identified as pneumococci, were further characterized using phenotypic and genotypic approaches. Phenotypic tests classified them as atypical pneumococci. Phylogenetic relationships were analyzed by using the sequences of seven housekeeping alleles from these isolates and from isolates of Streptococcus pneumoniae, Streptococcus mitis, Streptococcus oralis, and Streptococcus pseudopneumoniae. Four isolates grouped with S. pneumoniae, seven grouped with S. pseudopneumoniae, and three grouped with S. mitis. These results generally agreed with those obtained with an optochin susceptibility test and with the organization of the atp operon chromosomal region, encoding the F_oF₁ H⁺-ATPase (the target of optochin). All seven isolates grouping with S. pseudopneumoniae share the same spr1368-atpC-atpA gene order; all four grouping with S. pneumoniae share the spr1368-IS1239-atpC-atpA order, and two out of the three grouping with S. mitis share the spr1284-atpC-atpA order. In addition, evidence for recombination within the seven housekeeping alleles of the S. pseudopneumoniae population was provided by several methods: the index of association (0.4598, P < 0.001), the pairwise homoplasy index, and the split-decomposition method. This study confirms the existence of pneumococci among the alpha-hemolytic streptococci with DNA topoisomerase genes showing a mosaic structure and reveals a close relationship between atypical pneumococci and S. pseudopneumoniae.     

T2 hyperintensity along the cortico-spinal tract in cirrhosis relates to functional abnormalities

Magnetic resonance has shown T2 hyperintensity along the cortico-spinal tract in the brain of cirrhotic patients. This abnormality, which is reversible after liver transplantation, appears to correspond to mild edema. Because astrocytic edema present in hepatic encephalopathy may be responsible for neuronal dysfunction, we studied whether T2 hyperintensity along the cortico-spinal tract may relate to functional abnormalities. Twenty patients with cirrhosis underwent neuropsychologic tests, neurophysiologic study of the cortico-spinal tract with transcranial magnetic stimulation, and (1)H-magnetic resonance. The study was repeated 6 months after liver transplantation (n = 15) and was compared with a control group of healthy subjects (n = 11). Cirrhotic patients exhibited increased T2 signal and several functional abnormalities along the cortico-spinal tract (increased central motor conduction time, increased motor cortical threshold, and decreased motor-evoked potential amplitude). Functional abnormalities reversed after liver transplantation and were associated with normalization of T2 cortico-spinal hyperintensity and with improvement of minimal hepatic encephalopathy. In conclusion, T2 hyperintensity along the cortico-spinal tract in cirrhosis relates to functional abnormalities that are reversible after liver transplantation. These findings suggest that mild cerebral edema along the cortico-spinal pathway may cause neuronal dysfunction. These results support the participation of astrocytic edema in the pathogenesis of hepatic encephalopathy.