Patch-based 3D U-Net and transfer learning for longitudinal piglet brain segmentation on MRI.

BACKGROUND AND OBJECTIVES: In order to study neural plasticity in immature brain following early brain lesion, large animal model are needed. Because of its morphological similarities with the human developmental brain, piglet is a suitable but little used one. Its study from Magnetic Resonance Imaging (MRI) requires the development of automatic algorithms for the segmentation of the different structures and tissues. A crucial preliminary step consists in automatically segmenting the brain. METHODS: We propose a fully automatic brain segmentation method applied to piglets by combining a 3D patch-based U-Net and a post-processing pipeline for spatial regularization and elimination of false positives. Our approach also integrates a transfer-learning strategy for managing an automated longitudinal monitoring evaluated for four developmental stages (2, 6, 10 and 18 weeks), facing the issue of MRI changes resulting from the rapid brain development. It is compared to a 2D approach and the Brain Extraction Tool (BET) as well as techniques adapted to other animals (rodents, macaques). The influence of training patches size and distribution is studied as well as the benefits of spatial regularization. RESULTS: Results show that our approach is efficient in terms of average Dice score (0.952) and Hausdorff distance (8.51), outperforming the use of a 2D U-Net (Dice: 0.919, Hausdorff distance: 11.06) and BET (Dice: 0.764, Hausdorff distance: 25.91). The transfer-learning strategy achieves a good performance on older piglets (Dice of 0.934 at 6 weeks, 0.956 at 10 weeks and 0.958 at 18 weeks) compared to a standard training strategy with few data (Dice of 0.636 at 6 weeks, 0.907 at 10 weeks, not calculable at 18 weeks because of too few training piglets). CONCLUSIONS: In conclusion, we provide a method for longitudinal MRI piglet brain segmentation based on 3D U-Net and transfer learning which can be used for future morphometric studies and applied to other animals.

Security and reliability of CUSTOMBONE cranioplasties: A prospective multicentric study.

BACKGROUND: Repairing bone defects generated by craniectomy is a major therapeutic challenge in terms of bone consolidation as well as functional and cognitive recovery. Furthermore, these surgical procedures are often grafted with complications such as infections, breaches, displacements and rejections leading to failure and thus explantation of the prosthesis. OBJECTIVE: To evaluate cumulative explantation and infection rates following the implantation of a tailored cranioplasty CUSTOMBONE prosthesis made of porous hydroxyapatite. One hundred and ten consecutive patients requiring cranial reconstruction for a bone defect were prospectively included in a multicenter study constituted of 21 centres between December 2012 and July 2014. Follow-up lasted 2 years. RESULTS: Mean age of patients included in the study was 42±15 years old (y.o), composed mainly by men (57.27%). Explantations of the CUSTOMBONE prosthesis were performed in 13/110 (11.8%) patients, significantly due to infections: 9/13 (69.2%) (p<0.0001), with 2 (15.4%) implant fracture, 1 (7.7%) skin defect and 1 (7.7%) following the mobilization of the implant. Cumulative explantation rates were successively 4.6% (SD 2.0), 7.4% (SD 2.5), 9.4% (SD 2.8) and 11.8% (SD 2.9%) at 2, 6, 12 and 24 months. Infections were identified in 16/110 (14.5%): 8/16 (50%) superficial and 8/16 (50%) deep. None of the following elements, whether demographic characteristics, indications, size, location of the implant, redo surgery, co-morbidities or medical history, were statistically identified as risk factors for prosthesis explantation or infection. CONCLUSION: Our study provides relevant clinical evidence on the performance and safety of CUSTOMBONE prosthesis in cranial procedures. Complications that are difficulty incompressible mainly occur during the first 6 months, but can appear at a later stage (>1 year). Thus assiduous, regular and long-term surveillances are necessary.

Acute intracranial hypertension management in metastatic brain tumor: A French national survey.

BACKGROUND: Brain metastases occur in 15-30% of cancer patients and their frequency has increased over time. They can cause intracranial hypertension, even in the absence of hydrocephalus. Emergency surgical management of brain metastasis-related intracranial hypertension is not guided by specific recommendations. OBJECTIVE: We aimed to make a French national survey of emergency management of intracranial hypertension without hydrocephalus in the context of cerebral metastasis. METHODS: A national online survey of French neurosurgeons from 16 centers was conducted, consisting of three clinical files, with multiple-choice questions on diagnostic and therapeutic management in different emergency situations. RESULTS: In young patients without any previously known primary cancer, acute intracranial hypertension due to a seemingly metastatic single brain tumor indicated emergency surgery for all those interviewed; 61% aimed at complete resection; brain MRI was mandatory for 74%. When a primary cancer was known, 74% of respondents were more likely to propose surgery if an oncologist confirmed the possibility of adjuvant treatment; 27% were more likely to operate on an emergency basis when resection was scheduled after multi-disciplinary discussion, prior to acute degradation. CONCLUSION: Currently, there is no consensus on the emergency management of intracranial hypertension in metastatic brain tumor patients. In case of previously known primary cancer, a discussion with the oncology team seems necessary, even in emergency. Decision criteria emerge from our literature review, but require analysis in further studies.

Prognostic molecular markers with no impact on decision-making: the paradox of gliomas based on a prospective study.

This study assessed the prognostic value of several markers involved in gliomagenesis, and compared it with that of other clinical and imaging markers already used. Four-hundred and sixteen adult patients with newly diagnosed glioma were included over a 3-year period and tumour suppressor genes, oncogenes, MGMT and hTERT expressions, losses of heterozygosity, as well as relevant clinical and imaging information were recorded. This prospective study was based on all adult gliomas. Analyses were performed on patient groups selected according to World Health Organization histoprognostic criteria and on the entire cohort. The endpoint was overall survival, estimated by the Kaplan-Meier method. Univariate analysis was followed by multivariate analysis according to a Cox model. p14(ARF), p16(INK4A) and PTEN expressions, and 10p 10q23, 10q26 and 13q LOH for the entire cohort, hTERT expression for high-grade tumours, EGFR for glioblastomas, 10q26 LOH for grade III tumours and anaplastic oligodendrogliomas were found to be correlated with overall survival on univariate analysis and age and grade on multivariate analysis only. This study confirms the prognostic value of several markers. However, the scattering of the values explained by tumour heterogeneity prevents their use in individual decision-making.

[Local chemotherapy of malignant glioma: from syringe injections to nanotechnology]. / Chimiothérapie locale dans les gliomes malins: de l'injection à la seringue aux nanotechnologies.

Many arguments support the development of local therapies for malignant gliomas. Simple injections of antimitotic agents into the surgical cavity has been replaced by more sophisticated systems. Tissues can be infused with complex prolonged-release polymeric or lipidic systems with macroscopic, microscopic and now even nanometric particles. But, as for any drug, the developments of these new agents has been long and only very few reach the stage of the clinic trials.

Relevance of Ki-67 and prognostic factors for recurrence/progression of gonadotropic adenomas after first surgery.

OBJECTIVE: Gonadotropin-secreting pituitary adenomas carry a high risk of local recurrence or progression (R/P) of remnant tumor after first surgery. The clinical characteristics and the long-term outcome of these silent adenomas, which show no signs of endocrine hyperfunction, differ from those of other types of pituitary adenomas. However, to date, no study has focused specifically on gonadotropic adenomas. MATERIALS AND METHODS: To identify prognostic factors of R/P of remnants, we studied the postoperative outcome of 32 gonadotropic pituitary adenomas, defined on immunohistochemical staining, according to their clinical and radiological characteristics as well as the Ki-67 labeling index (LI). RESULTS: The Ki-67 LI failed to provide independent information for the identification of patients at risk of progression of remnants or recurrence. Multivariate survival analysis (Cox regression) showed that neither invasiveness nor remnant tumors nor hyposomatotropism influenced tumor recurrence. The strongest predicting factors of R/P were the antero-posterior (AP) diameter in the sagittal plane (P = 0.014), and the age of the patient at surgery (P = 0.047), with younger patients being at greater risk. Hazard ratios were 2.11 for each 5 mm increase in AP diameter and 0.57 for every 10 years of age. CONCLUSION: The two simple clinical criteria revealed by our study, the AP diameter of the tumor and the age of the patient, should be helpful in planning clinical management and radiological monitoring after first surgery of gonadotropic adenomas, while awaiting the identification of other pathological parameters.

Intrathecal baclofen in the treatment of spasticity, dystonia and vegetative disorders.

Baclofen (beta-p-chlorophenyl-GABA) binds to a number of spinal and cerebral sites and depresses the excitability of motor neurons. Intrathecal administration induces much higher CSF concentrations compared to the limited passage through the blood-brain barrier after oral administration. The development of reliable implanted pumps allows long-term intrathecal baclofen treatment (ITB). Baclofen is mainly an antispastic drug and the main indication of ITB is generalized lower limb spasticity in spinal cord injury and multiple sclerosis. The side-effects are due to either drug over-dose or withdrawal and to malfunctions of the implanted device (disconnections of the catheter, infections, etc.). Large numbers of patients have been treated over the past twenty years. More recently, baclofen has been used in the treatment of spasticity of cerebral origin, and in the treatment of other motor disorders, mainly dystonia. The results in cerebral palsy are promising and ITB's role will probably grow in the management of the movement disorders of these children. Further studies are required on the exact site of action, on the possible association with other drugs, especially clonidine and on the development of sustained release formulations.

[Two consecutive episodes of intracerebral hemorrhage as the presenting feature of polyarteritis nodosa]. / Deux hémorragies cérébrales révélatrices d'une périartérite noueuse.

We report a case of polyarteritis nodosa revealed by intracranial haemorrhage. A 40-year-old woman presented two episodes of cerebral haemorrhage twelve days apart, the second due to an aneurysm rupture. The diagnosis of polyarteritis nodosa (PAN) was based on the following criteria: histological aneurysm examination, angiography suggesting PAN with cerebral, renal and splenic localizations, loss of weight and cutaneous nodules. Cerebral haemorrhage in PAN is rare and exceptionally the presenting feature of the disease.

[Is the right hemisphere really minor? Involvement in the repair of bodily injury]. / L'hémisphère droit est-il vraiment mineur ? Implication dans la réparation du dommage corporel.

An appraisal mission regarding the repair of physical injury is based on the classification of the effects of injury and scales. These scales are surprisingly incomplete concerning the symptoms due to a right hemisphere injury. However, these symptoms can cause an important handicap in numerous activities, social, affective and professional. This paper reviews the recent functional anatomic knowledge of the right hemisphere functions, visuo-spatial cognition, intentional process and social cognition. The impacts of this appraisal data, as well as suggestions for new scales, are outlined.

Carmustine wafer implantation for high-grade gliomas: Evidence-based safety efficacy and practical recommendations from the Neuro-oncology Club of the French Society of Neurosurgery.

There is a growing body of evidence that carmustine wafer implantation during surgery is an effective therapeutic adjunct to the standard combined radio-chemotherapy regimen using temozolomide in newly diagnosed and recurrent high-grade glioma patient management with a statistically significant survival benefit demonstrated across several randomized clinical trials, as well as prospective and retrospective studies (grade A recommendation). Compelling clinical data also support the safety of carmustine wafer implantation (grade A recommendation) in these patients and suggest that observed adverse events can be avoided in experienced neurosurgeon hands. Furthermore, carmustine wafer implantation does not seem to impact negatively on the quality of life and the completion of adjuvant oncological treatments (grade C recommendation). Moreover, emerging findings support the potential of high-grade gliomas molecular status, especially the O(6)-Methylguanine-DNA Methyltransferase promoter methylation status, in predicting the efficacy of such a surgical strategy, especially at recurrence (grade B recommendation). Finally, carmustine wafer implantation appears to be cost-effective in high-grade glioma patients when performed by an experienced team and when total or subtotal resection can be achieved. Altogether, these data underline the current need for a new randomized clinical trial to assess the impact of a maximal safe resection with carmustine wafer implantation followed by the standard combined chemoradiation protocol stratified by molecular status in high-grade glioma patients.

In vitro investigation of lipid implants as a controlled release system for interleukin-18.

Operating on the inductive and effective phases of an anti-tumor immune response and uncovering pivotal functions that may reduce cancer cell growth, interleukin-18 (IL-18) appears to be an attractive candidate for the sustained local adjuvant immunotherapeutic treatment of brain gliomas. The objective of this work was to develop IL-18 loaded lipid implants as a controlled delivery system. For the preparation of protein loaded triglyceride matrix material, a solid-in-oil (s/o) dispersion technique was chosen for which protein particles in the micrometer range were first prepared by co-lyophilization with polyethylene glycol (PEG). Implants of 1 mm diameter, 1.8 mm height and 1.8 mg weight were manufactured by compression of the powder mixture in a specially designed powder compacting tool. The in vitro release behavior of 125I-Bolton-Hunter-radiolabeled IL-18 was assessed in a continuous-flow system. A cell culture assay was established for the determination of bioactivity of released IL-18. Implants showed a continuous release of 10-100 ng IL-18 per day for 12 days. A progressive integrity loss was observed with ongoing release, which would be related to protein degradation during incubation. The initially released fraction proved complete retention of bioactivity, indicating that the manufacturing procedure had no detrimental effects on protein stability.

Development and characterization of interleukin-18-loaded biodegradable microspheres.

Immunostimulation represents a promising approach designed to specifically eradicate malignant cells. Since glioma tumour cells hole up in the central nervous system (CNS) in a particularly inauspicious milieu to antitumour immune reactions we here propose a new strategy to revert the properties of this microenvironment by administering an antitumour cytokine into the CNS tumour itself. Thus, biodegradable poly(D,L-lactide-co-glycolide) (PLGA) sustained-release microspheres for stereotaxic implantation loaded with interleukin-18 (IL-18), that is known to exert antitumour activity and trigger immune cell-mediated cytotoxicity, were developed. Different tests for assessing IL-18 bioactivity were set-up and evaluated. A specific bioassay was considered as the most reliable test. The stability and integrity of IL-18 was then verified during the encapsulation process. Consequently, two procedures of IL-18 encapsulation in PLGA microparticles (W/O/W and S/O/W) were investigated. As determined by radiolabelling studies using 125I-IL-18 and a continuous flow system, the in vitro release profile of IL-18 was optimum with S/O/W method with a moderate burst effect and a subsequent progressive discharge of 16.5+/-8.4 ng/day during the next 21 days against 6.1+/-4.2 ng/day with the W/O/W method. Considering analytical testing of IL-18 together with its preserved biological activity after release from microspheres, amounts of the active cytokine obtained with S/O/W method were relevant to plan in vivo evaluation to validate the therapeutic strategy.

Development of new polymer-based particulate systems for anti-glioma vaccination.

Biodegradable and biocompatible microspheres represent a promising alternative to conventional adjuvants for anti-tumour vaccination. Focusing on glioma, we developed two poly(D,L-lactide-co-glycolide) (PLGA)-based particulate systems presenting tumour antigens associated with plasma membranes or with cell lysates. Glioma cell fractions were prepared for adsorption onto poly-D-lysine (PDL)-coated PLGA microspheres formulated using a double-emulsion procedure. Adsorption was followed by (125)I-radiolabelling, Western blot and confocal laser scanning microscopy. Only a panel (34%) of the proteins isolated from both cell fractions adsorbed onto PDL-coated PLGA microspheres. The integrity of the epitopes after loading was preserved, as shown by identification of plasma membrane and cytoplasmic markers. Finally, one of the major potential advantages of those particulate systems resides in the fact they not only serve as injectable adjuvant matrices presenting tumour antigens to antigen presenting cells, but also as potential reservoirs for controlled delivery of active immunostimulant molecules.

Combining polymeric devices and stem cells for the treatment of neurological disorders: a promising therapeutic approach.

Cell therapy will probably become a major therapeutic strategy for neuronal disorders in the coming years. Nevertheless, due to poor survival of grafted cells and limited differentiation and integration in the host tissue, certain ameliorations must be envisaged. To address these difficulties, several strategies have been developed and among them, two methods seem particularly promising : in situ controlled drug delivery and implantation of cells adhered on biomaterial-based scaffolds. Indeed, the ability of drugs, such as growth factors, to regulate neuronal survival and/or plasticity infers the use of these molecules to treat neurodegeneration associated with human diseases. Moreover, the synthesis of cell scaffolds which mimic the extra-cellular matrix can help guide morphogenesis and tissue repair. Furthermore, cells can be cultivated on these matrices that may eventually make graft therapy a more practical approach for the treatment of neurological diseases. Nevertheless, for those two encouraging approaches multiple parameters have to be considered, such as the drug targeting strategy, but also the physical and morphological characteristics of the scaffold and the type of cells to be conveyed. This review thus focuses on those two promising strategies and also on their possible association to improve stem cell therapy of neurodegenerative disorders. Indeed, tissue replacement by grafting cells within or adhered onto drug delivering biomaterial-based devices, has recently been reported and seems to be very promising.

Pharmacologically active microcarriers: a tool for cell therapy.

To overcome certain problems encountered in cell therapy, particularly cell survival, lack of cell differentiation and integration in the host tissue, we developed pharmacologically active microcarriers (PAM). These biodegradable particles made with poly(D,L-lactic-co-glycolic acid) (PLGA) and coated with adhesion molecules may serve as a support for cell culture and may be used as cell carriers presenting a controlled delivery of active protein. They can thus support the survival and differentiation of the transported cells as well as their microenvironment. To develop this tool, nerve growth factor (NGF)-releasing PAM, conveying PC12 cells, were produced and characterized. Indeed, these cells have the ability to differentiate into sympathetic-like neurons after adhering to a substrate, in the presence of NGF, and can then release large amounts of dopamine. Certain parameters such as the size of the microcarriers, the conditions enabling the coating of the microparticles and the subsequent adhesion of cells were thus studied to produce optimized PAM.

[Botulinum toxin injections and hypertonic upper limbs. Which functional results?]. / Membres supérieurs fonctionnels hypertoniques et toxine botulique. Quels résultats fonctionnels?

OBJECTIVES: To assess the efficacy of botulinum toxin injections for hypertonic upper limbs in patients with residual motricity that allows a functional use of the hand. METHODS: Patients were seen between February 2000 and November 2002, before and after botulinum toxin injections for hypertonic upper limbs due to upper motor neuron syndrome. All patients had voluntary motricity in fingers and wrist extensors. Impairment (range of motion, spasticity [Ashworth's scale]), pain (10 centimeters visual analog scale) prehension (400-point measure) and patients' satisfaction were recorded. Two or three functional goals were predefined. Patients were injected after locating the target area with neurostimulation. The aim of the injections was functional improvement. RESULTS: Eight patients were included. After injections, mean pain score decreased by 3.4 points; mean spasticity decreased by 1.0; and prehension improved, especially for bimanual functions. Three-quarters of the functional goals were reached. Optimal efficacy required repeated injections, with modification of muscle targets and doses. CONCLUSION: Botulinum toxin injection is efficient for impairment, pain and prehension in hypertonic upper limbs, even if the hypertonic hand is still the "nondominant" hand. Motricity in antagonist muscles is essential for functional improvement, and the assessment must include bimanual tasks. Intrinsic as well as extrinsic muscles must be injected and a neurostimulator used for forearm muscles. Comparative studies are required to define more clearly the place of this treatment among medical and surgical treatments of spasticity.

[Surgery of brain metastases]. / Place de la chirurgie dans la prise en charge des métastases cérébrales.

Surgical excision of brain metastases has been well evaluated in unique metastases. Two randomized phase III trial have shown that combined with adjuvant whole brain radiotherapy, it significantly improves overall survival. However, even in the presence of multiple brain metastases, surgery may be useful. Also, even in lesions amenable to radiosurgery, surgical resection is preferred when tumors displayed cystic or necrotic aspect with important edema or when located in highly eloquent areas or cortico-subcortically. Furthermore, surgery may have a diagnostic role, in the absence of histological documentation of the primary disease, to rule out a differential diagnosis (brain abscess, lymphoma, primary tumor of the central nervous system or radionecrosis). Finally, the biological documentation of brain metastatic disease might be useful in situations where a specific targeted therapy can be proposed. Selection of patients who will really benefit from surgery should take into account three factors, clinical and functional status of the patient, systemic disease status and characteristics of intracranial metastases. Given the improved overall survival of cancer patients partially due to the advent of effective targeted therapies on systemic disease, a renewed interest has been given to the local treatment of brain metastases. Surgical resection currently represents a valuable tool in the armamentarium of brain metastases but has also become a diagnostic and decision tool that can affect therapeutic strategies in these patients.

Intraseptal implantation of NGF-releasing microspheres promote the survival of axotomized cholinergic neurons.

Neurotrophic factors therapy requires their precise delivery to the targeted neuronal population. For this purpose, a wide range of strategies have been developed, and among them the stereotaxic implantation of biodegradable microparticles. To assess the in vivo activity of NGF-releasing PLGA microspheres, unloaded and NGF-loaded microparticles were implanted in the rat brain, near the septal cholinergic neurons, axotomized by an unilateral transection of the fornix-fimbria. Histological analysis at two and six weeks after implantation revealed a non-specific astro- and micro-glial reaction around the microspheres, identical for both unloaded and NGF-loaded microspheres. No neuronal toxicity was noticed, and healthy looking neurons were observed in contact with the microspheres. In the non-treated animals, the percentage of axotomized surviving neurons, when compared to the contralateral intact side, was 31 +/- 2 and 27 +/- 1% at two and six weeks, respectively. Unloaded microspheres caused no protective nor neurotoxic effects (40 +/- 9 and 39 +/- 6% of surviving cholinergic neurons at two and six weeks, respectively). In contrast, NGF-loaded microspheres showed a significant effect on the survival of axotomized cholinergic neurons at two and six weeks after implantation (66 +/- 9 and 61 +/- 5% when compared to the contralateral intact side, respectively). These results show that PLGA microparticles present no neurotoxicity and release sufficient amounts of bioactive NGF to significantly limit the lesion-induced disappearance of cholinergic neurons in the septum during at least six weeks. PLGA microparticles can be used in the future to administer neurotrophic factors in central nervous system disorders.

Biodegradation and brain tissue reaction to poly(D,L-lactide-co-glycolide) microspheres.

The therapeutic application of neuroactive molecules in neuroscience is limited, due to the problems posed by the administration of these drugs (peripheral metabolism, systemic effect and passage of the blood-brain barrier). One solution is the implantation in the brain of biodegradable polymer devices with controlled release of a neuroactive drug. The biodegradation and tissue reaction of the copolymer poly(D,L-lactide-co-glycolide) microspheres prepared by the solvent evaporation method, radiosterilized and stereotactically implanted in the rat brain were studied by routine staining, immunohistochemistry and transmission electronic microscopy. The brain tissue reaction observed was a non-specific astrocytic proliferation and a macrophagous-microglial cell reaction, typically found following damage to the central nervous system. Some foreign-body giant cells were observed and the inflammatory and macrophagous reaction decreased dramatically after 1 month and almost ended after 2 months when the microspheres were totally biodegraded. The copolymer poly(D,L-lactide-co-glycolide) microspheres may be considered biocompatible to the brain tissue.

In vivo evaluation of pharmacologically active microcarriers releasing nerve growth factor and conveying PC12 cells.

Cell therapy will probably become a major therapeutic strategy in the coming years. Nevertheless, few cells survive transplantation when employed as a treatment for neuronal disorders. To address this problem, we have developed a new tool, the pharmacologically active microcarriers (PAM). PAM are biocompatible and biodegradable microparticles coated with cell adhesion molecules, conveying cells on their surface and presenting a controlled delivery of growth factor. Thus, the combined effect of growth factor and coating influences the transported cells by promoting their survival and differentiation and favoring their integration in the host tissue after their complete degradation. Furthermore, the released factor may also influence the microenvironment. In this study, we evaluated their efficacy using nerve growth factor (NGF)-releasing PAM and PC12 cells, in a Parkinson's disease paradigm. After implantation of NGF-releasing or unloaded PAM conveying PC12 cells, or PC12 cells alone, we studied cell survival, differentiation, and apoptosis, as well as behavior of the treated rats. We observed that the NGF-releasing PAM coated with two synthetic peptides (poly-D-lysine and fibronectin-like) induced PC12 cell differentiation and reduced cell death and proliferation. Moreover, the animals receiving this implant presented an improved amphetamine-induced rotational behavior. These findings indicate that PAM could be a promising strategy for cell therapy of neurological diseases and could be employed in other situations with fetal cell transplants or with stem cells.