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BackgroundModel organisms are at the core of life science research. Notable examples include the mouse as a model for humans, baker’s yeast for eukaryotic unicellular life and simple genetics, or the enterobacteria phage λ in virology. Plant research was an exception to this rule, with researchers relying on a variety of non-model plants until the eventual adoption of Arabidopsis thaliana as primary plant model in the 1980s. This proved to be an unprecedented success, and several secondary plant models have since been established. Currently, we are experiencing another wave of expansion in the set of plant models.ScopeSince the 2000s, new model plants have been established to study numerous aspects of plant biology, such as the evolution of land plants, grasses, invasive and parasitic plant life, adaptation to environmental challenges, and the development of morphological diversity. Concurrent with the establishment of new plant models, the advent of the ‘omics’ era in biology has led to a resurgence of the more complex non-model plants. With this review, we introduce some of the new and fascinating plant models, outline why they are interesting subjects to study, the questions they will help to answer, and the molecular tools that have been established and are available to researchers.ConclusionsUnderstanding the molecular mechanisms underlying all aspects of plant biology can only be achieved with the adoption of a comprehensive set of models, each of which allows the assessment of at least one aspect of plant life. The model plants described here represent a step forward towards our goal to explore and comprehend the diversity of plant form and function. Still, several questions remain unanswered, but the constant development of novel technologies in molecular biology and bioinformatics is already paving the way for the next generation of plant models.

Targeting surface receptors overexpressed on cancer cells is one way to specifically treat cancer versus normal cells. Vintafolide (EC145), which consists of folate linked to a cytotoxic small molecule, desacetylvinblastine hydrazide (DAVLBH), takes advantage of the overexpression of folate receptor (FR) on cancer cells. Once bound to FR, vintafolide enters the cell by endocytosis, and the reducing environment of the endosome cleaves the linker, releasing DAVLBH to destabilize microtubules. Vintafolide has shown efficacy and improved tolerability compared with DAVLBH in FR-positive preclinical models. As the first FR-targeting drug to reach the clinic, vintafolide has achieved favorable responses in phase II clinical trials in FR-positive ovarian and lung cancer. However, some FR-positive patients in these clinical trials do not respond to vintafolide. We sought to identify potential biomarkers of resistance to aid in the future development of this and other FR-targeting drugs. Here, we confirm that high P-glycoprotein (P-gp) expression was the strongest predictor of resistance to DAVLBH in a panel of 359 cancer cell lines. Furthermore, targeted delivery of DAVLBH via the FR, as in vintafolide, fails to overcome P-gp–mediated efflux of DAVLBH in both in vitro and in vivo preclinical models. Therefore, we suggest that patients whose tumors express high levels of P-gp be excluded from future clinical trials for vintafolide as well as other FR-targeted therapeutics bearing a P-gp substrate. Mol Cancer Ther; 15(8); 1998–2008. ©2016 AACR.

The pons is covered by a rich venous network offering numerous vascular landmarks in MRI and during surgery. We present an original study of the veins as they appear on MR multiplanar scans after gadolinium IV injection. This prospective study is based on 40 consecutive patients with normal posterior fossa structures. One of the major venous collectors follows the pons: the superior petrosal v. was identified on MRI in 95% of our cases. Its hooklike extremity drains into the superior petrosal sinus. The inferior petrosal v. was never identifiable. The superficial pontine venous network are identified in 72.5% of cases in the axial plane and were organised in longitudinal and transverse collectors, whose MR aspects are presented here.

Magnetic resonance imaging (MRI) has progressively become the major or even the only imaging procedure for displaying the vascular relationships of the brainstem in the context of infra-tentorial lesions. In order to assess the MR sectional anatomy of the bulbar vv. 40 normal patients were examined in the MR axial, frontal and sagittal planes after gadolinium i.v. injection. The bulbar venous networks were inconstantly visualised: anterior vv. (16%). posterior (3%), lateral (8%). The vein of the lateral recess of the fourth ventricle was constant in the three planes; the inferior petrosal sinus could be seen in 82% of cases. Their relation with the posterior fossa structures are emphasised and discussed.

Human cytomegalovirus (CMV), a herpesvirus, is an important cause of morbidity and mortality in immunocompromised patients. When studying hyper-immediate-early events after contact between CMV virions and the cell membrane, we observed a hypophosphorylation of cellular proteins within 10 min. This can be explained in part by our finding that purified CMV contains serine/threonine protein phosphatase activities. Biochemical analyses indicate that this protein phosphatase activity has all characteristics of type 1 and 2A protein phosphatases (PP1 and PP2A). Specifically, PP1 accounts for approximately 30% and PP2A accounts for the remaining 70% of the phosphorylase phosphatase activity found. CMV produced in astrocytoma cells stably expressing an amino-terminally tagged PP2A catalytic subunit contained tagged enzyme, thus demonstrating the cellular origin of CMV-associated PP2A. PP2A is specifically found inside the virus, associated with the nucleocapsid fraction. Western blot (immunoblot) analysis of purified virus revealed the presence of the catalytic subunits of PP2A and PP1. Furthermore, the catalytic subunit of PP2A appears to be complexed to the regulatory subunits PR65 and PR55, which is also the most abundant configuration of this enzyme found in the host cells. Incubation of virus with okadaic acid before contact of CMV with cells prevented hypophosphorylation of cellular proteins, thus demonstrating the role of CMV-associated phosphatases in this phenomenon. CMV can thus transport an active enzyme from one cell to another.

Human cytomegalovirus (CMV) infection can elicit a transitory, but profound, immunodepression in immunocompetent individuals. Cytopathogenic destruction of CMV-infected leukocytes alone does not seem sufficient to explain this phenomenon, which suggests that immune system mediators (cytokines) may play a role in amplifying local modifications wrought by CMV infection. We reported previously that transforming growth factor beta 1 (TGF-beta 1) stimulates CMV replication (J. Alcami, C. V. Paya, J. L. Virelizier, and S. Michelson, J. Gen. Virol. 74:269-274, 1993). Since TGF-beta 1 can have profound negative effects on cell growth and immune responses, we investigated the induction of TGF-beta 1 following CMV infection of permissive fibroblasts. TGF-beta 1 promoter was activated by immediate-early (IE) proteins in the absence of infection and transactivated at 5 and 9 h after infection. TGF-beta 1 mRNA increased during the early phase of infection, suggesting that this phenomenon is due to enhanced transcription of the TGF-beta 1 gene. A comparative study of the influence of CMV infection and IE protein expression on TGF-beta 1 promoter function in permissive cells pointed to a possible cooperative role between IE proteins and protein(s) expressed during the early phase of viral infection. Induction of TGF-beta 1 by CMV infection could modify infected cells individually, surrounding tissues, and systemic immune reactions to the advantage of virus replication by both upregulating CMV replication and downregulating host immune responses.

Receptor tyrosine kinase RET is normally expressed at low levels in chromaffin cells and high levels in sympathetic neurons. Paradoxically, it is overexpressed in subsets of pheochromocytomas. The overexpressed protein is usually wild-type, except in multiple endocrine neoplasia type 2. Possible explanations for overexpression include tumor origin from RET-expressing sympathoadrenal progenitors that escape developmental culling during embryogenesis, or reactivation of signaling pathways related to neuronal differentiation. Normal adult chromaffin and pheochromocytoma cells can undergo neuron-like differentiation in cell culture. In this investigation, cultured cells from two normal human adrenal medullas, two of three human pheochromocytomas, and one extra-adrenal paraganglioma showed RET induction corresponding with extensive nerve growth factor-induced outgrowth of neurite-like processes, while one pheochromocytoma showed neither processes nor RET induction. RET was similarly upregulated in parallel with process outgrowth in cultures of normal rat chromaffin cells and PC12 rat pheochromocytoma cells. In contrast, mouse pheochromocytoma cells that constitutively express high levels of wild-type RET together with other neuronal progenitor markers showed no further RET increase after cyclic AMP-induced process outgrowth. The RET-activating ligand GDNF was anti-apoptotic for mouse pheochromocytoma but not for PC12 cells. The findings suggest that overexpression of RET in pheochromocytomas could result either from a secondary event that activates signaling pathways mediating adult chromaffin cell plasticity or as a component of a persistent sympathoadrenal progenitor phenotype. Whether wild-type RET contributes to tumor development or is merely a lineage marker for cells at various stages of neuronal differentiation may vary, with other tumor characteristics.

Most urologists treating stone disease with any method (ESWL, PCL, URS) have encountered problems of poor stone visualization with fluoroscopy. This difficulty to localize urinary tract (UT) stones or fragments may result in incomplete stone extraction, prolonged surgery and increased risk of recurrence and post-operative complications. We have sought and found means to increase the radioopacity of mineral UT stones by a simple pre-operative perfusion technique. The capacity of radioopacification has first been demonstrated in in vitro incubations of fragments of human mineral stones with aqueous solutions of barium, of the lanthanides and of the two natural actinides. Most of the incubations led to considerable radio-contrast enhancement and heavy metal incorporation, measured by X-ray fluorescence analysis. Dogs with implanted human stone fragments were used as an in vivo model. The UT were perfused through a retrograde pyelic catheter with heavy metal salts solutions, the ensuing radioopacification of the implanted UT-stones was estimated by abdominal radiographies and the metal incorporation was measured on the retrieved stones. Considerable radioopacity enhancement together with heavy metal incorporation was observed for the following elements: Sr, Ba and the lanthanides Gd and Yb. The pathological evaluation of the urothelial linings from animals treated with lanthanide salt showed no toxic effects.

To study prognostic factors of obliteration and risk factors of brain radiation necrosis in order to propose an algorithm for radiosurgery prescription for cerebral arteriovenous malformations (cAVM).One hundred and seventy-nine patients were analysed. Radiosurgery delivered 6 or 10 MV X-rays by arc therapy in 84% of cases, or by fixed field in 16% of cases using two different micro-multileaf collimators (micro-MLC). Follow-up consisted of screening radiation necrosis by MRI every 6 months, and assessing local control by arteriography every 2 years. Obliteration was defined as at least 95% reduction of cAVM volume. Cox proportional hazard model was used to evaluate the local control and the appearance of radiation necrosis over time.Local control rate was 82.7% with the mean follow-up of 3.1 years (0.5-11). Significant prognostic factors were: simple nidus (RR=2.8, p0.0001), number of embolizations before radiosurgery below 4 (RR=2.9, p0.0001), prescribed dose to the periphery of at least 18 Gy (RR=2, p=0.0002), nidus volume below8cm(3) (RR=1.9, p=0.0002), and number of table positions below six (RR=1.4, p=0.05). Radiation necrosis rate was 11.2% with a mean time to onset of 18 months. Significant predictive factors were: fixed field versus arc therapy (according to MLC RR=9.1, p0.0001, and RR=15.1, p=0.01), age below 30 years (RR=2.5, p=0.04), depth of cAVM greater than or equal to 7 cm (RR=7.6, p=0.008), and volume of brain tissue covered by the 12 Gy isodose (V12 Gy) of at least 11 cm(3) (RR=7.8, p=0.05).A radiosurgery prescription algorithm taking into account the prescribed dose to the periphery (or = 18 Gy) and reduction of V12 Gy was elaborated from these data.

The lack of consensus in the management of unruptured intracranial aneurysms (UIA) has resulted in a variety of different clinical practices. The aim of this study is to analyze these different practices.A questionnaire concerning the management of UIA was mailed out to French neurosurgeons (NS) and neuroradiologists (NR). Eighteen responses from 17 teams of NS and 23 responses from 19 teams of NR were included in our analysis.In making a therapeutic decision, about three-quarters of both NR and NS take into account the age of the patient and all of our responders except one consider the aneurysm's morphology, especially its size and neck structure. Pinpointing the location of the aneurysm is an important factor for 61% of NR and 40% of NS. Information concerning the risk of aneurysm rupture and the risks of treatment is routinely given to the patient orally and, sometimes, in writing. The follow-up of UIA treated by NR usually consists of one X-ray angiography and several MR angiographic (MRA) films taken over a period of at least five years and, sometimes, for the rest of the patient's life (22%). The follow-up after surgical treatment mainly comprises X-ray angiography for a limited period of time-usually from five to ten years. The follow-up of untreated aneurysms is usually by either MRA or angioCT. For most NR, the duration of follow-up is long and, sometimes, unlimited. For NS, the duration is more difficult to pinpoint: the response was indeterminate in 28 and 33% gave no response at all. If the first screening tests negative, 44% of NS and 61% of NR propose a repeat screening.Given the differences in the management of UIA as revealed by this survey, a multidisciplinary approach that combines the various clinical practices may be the best way forward.

Pheochromocytomas are catecholamine-producing tumors of the adult adrenal medulla. They are rare in humans and most other species but common in laboratory rats. However, the relevance of rat pheochromocytomas as a model for their human counterparts is uncertain. Previous studies of spontaneous and drug-induced rat pheochromocytomas and the PC12 pheochromocytoma cell line suggested a distinctive noradrenergic phenotype, possibly reflecting origin from a progenitor not present in the adult human adrenal. In this study, we studied 31 pheochromocytomas derived from test and control male and female rats in toxicologic studies for expression of the epinephrine-synthesizing enzyme phenylethanolamine-N-methyltransferase (PNMT) and the receptor tyrosine kinase Ret. PNMT, which defines adrenergic chromaffin cells, is frequently expressed in human pheochromocytomas, often in tumors that also overexpress RET. We also tested for the expression of the cell cycle checkpoint protein p27(Kip1), which recently was reported absent in pheochromocytomas from a strain of rats with a hereditary mixed multiple endocrine neoplasia (MEN)-like syndrome. Using immunoblots, we demonstrated PNMT expression in almost 50% of the 31 tumors, although often at lower levels than in normal rat adrenal medulla. The majority of tumors overexpressed Ret. There was no apparent correlation between PNMT and Ret. However, in this study, PNMT expression was strongly associated with tumors arising in female rats, while overexpression of Ret did not show a sex predilection. Robust expression of p27(Kip1) was seen in all tumors from the toxicologic studies and also in a small sample of pheochromocytomas from Long-Evans rats, which were reported to have a mixed MEN-like syndrome in the 1980s. The present results show that rat pheochromocytomas have greater phenotypic diversity than previously believed and greater similarity to their human counterparts with respect to these two important markers. Loss of p27(Kip1) does not appear to account for the high frequency of pheochromocytomas in commonly utilized rat strains.

We report the MR imaging findings in a 20 year old woman with status epilepticus of more than 3 months duration following an episode of lymphocytic meningitis. Repeated MR examinations showed progressive symmetrical cortical lesions, followed by subcortical and basal ganglia lesions which evolved to cortical laminar necrosis and hemorrhagic necrosis with eventual subcortical cerebral atrophy. This case has similarities with animal status epilepticus models. Biological investigations were all negative. This suggests that the brain lesions may be related to the prolonged status epilepticus.

Medical risk management has one main purpose: to ensure the safety of care. The law of March 2002 has generated a true cultural revolution. The radiologist is involved with new and difficult areas of medical liability due to technical advances, the increasing number of imaging techniques, the increasing complexity of imaging techniques, their efficiency and the need for multidisciplinary approach. Imaging recommendations requiring increasing levels of technical and clinical skills. The radiologist is liable with regards to the indications of imaging studies, and also with regards to informed consent. The prevention of medicolegal problems is achieved by competency, which must be combined to good liability insurance and ongoing vigilance supported by appropriate continuous medical education.

Intra spinal primary melanoma is a rare entity. We report a new case, atypical in relation to its primary radicular location, and to its early metastatic intradural and extra-medullary location, six months later. MRI is the more valuable examination, showing a spontaneously hyper-intense lesion on T1-weighted MR images, intense enhancement after gadolinium administration, and decreased signal on T2-weighted MR images, thus suggesting a diagnosis of melanocytic or hemorrhagic lesion. Signal abnormalities are not specific and definitive diagnosis is established after histological analysis.

Naturally, neuroimaging emergencies are a component of the global subject of emergencies that have for several years been a frequent subject in the press. The current situation is the consequence of the evolution of ideas from contractual liability to the frequently discussed principle of precaution. Examples offered by the daily practice allow to emphasize the main difficulties: diagnosis of headaches, seizure episode on public roads, head trauma, stroke... The medical liability of the neuroradiologist is not the same for diagnostic or interventional neuroradiology; it can sometimes be shared with other physicians. This liability includes the indication, the quality of the diagnosis, the information of the patient and relatives, the communication of results with other physicians, the maintenance of the equipment... Knowledge of potential pitfalls allows preventive measures including competence of the neuroradiologist, informed patient consent, and written precise protocols are the most important. However, according to the evolution of our societies, it is likely that it will become increasingly difficult to achieve a professional neuroradiology career without being questioned; it is thus advisable to be prepared for such eventuality.

To investigate factors predisposing to spontaneous hemorrhage in the early period after embolization of brain arteriovenous malformations (AVMs).The authors report 15 cases of spontaneous hemorrhage in a consecutive series of 492 brain AVMs totally or partially treated with intranidal injections of a polymerizing mixture, from 1984 to June 1998. Retrospective analysis of the records was performed with special attention to the angio-architectural features before embolization, details of embolization procedures and induced angiographic modifications.Pre-embolization features of greater incidence were the presence of steal phenomena (87%), multiple feeding arteries (100%), a compact aspect of the nidus (93%), and lobar topography (87%). In most cases the volume of injected glue exceeded 1 ml (80%), venous embolization was significant (67%) and immediate angiographic control showed venous stagnation in and/or around the nidus (80%). Four patients were asymptomatic (incidental discovery on systematic CT at day 3). Among the remaining 11 symptomatic patients, 6 were operated to evacuate an intracerebral hematoma, outcome was good for 4, 5 were left with sequelae and 2 died.Spontaneous hemorrhagic complications affected 3.04% of embolized patients. The combination of certain angio-architectural features, significant venous embolization and persistent venous stagnation within the nidus seem to have some predictive value of high risk hemorrhage. In light of this, additional preventive measures must be taken and a neurosurgical team systematically kept on standby.

The endovascular treatment of vasospasm is effective when implemented rapidly. However its indication often proves difficult on account of the lack of diagnostic arguments or the difficulties in obtaining them in daily practice. We report a case that highlights the relevance of MRI in the decision-making process. A 37-year-old patient presented with symptomatic vasospasm of the middle cerebral artery and was subjected to morphological, diffusion- and perfusion-weighted MRI. These investigations confirmed the presence of significant oligemia in the MCA territory and revealed onsetting diffusion disorders. Angioplasty was immediately performed, resulting in normal diffusion and hemodynamic parameters and complete regression of clinical signs. This case highlights the relevance of MRI when assessing vasospasm before treatment. Coupled with transcranial Doppler, it should help teams quickly select patients most likely to benefit from angioplasty.

Shortly before his death in 1995, Kenneth B. Schwartz, a cancer patient at Massachusetts General Hospital (MGH), founded The Kenneth B. Schwartz Center at MGH. The Schwartz Center is a nonprofit organization dedicated to supporting and advancing compassionate health care delivery, which provides hope to the patient, support to caregivers, and encourages the healing process. The center sponsors the Schwartz Center Rounds, a monthly multidisciplinary forum where caregivers reflect on important psychosocial issues faced by patients, their families, and their caregivers, and gain insight and support from fellow staff members. Burnout describes the end result of stress in the professional life of a physician or caregiver and combines emotional exhaustion, depersonalization and low personal accomplishment. This problem is common in health care workers in every specialty and may affect not only personal satisfaction, but also the quality of care delivered to patients. Burnout is particularly relevant in oncology where caregivers work closely with patients who have life-threatening illnesses and therapy often has only a limited impact. Burnout was discussed in the rounds with an emphasis on factors which precipitate or prevent stress among health care workers. Presentations were made by Dr. Canellos of the Dana Farber Cancer Institute, and Dr. Picard of the Institute for Health Professions. Staff discussed the main issues contributing to burnout including the health care system, lack of time and inadequate training. They considered preventative measures including psychological support of the health care team, communication and management skills, and effective coping mechanisms.

Cerebral sulci identification process is based on several formal rules: it consists a series of steps allowing the identification of the major sulci. The process may be variable for each of us and we propose to read the images in certain order starting with the frontal lobe and its superior frontal gyrus than precentral and central gyri followed by the lateral fissure. Then the insular, lateral parietal and medial hemispheric regions. Finally the major sulci within the temporal and occipital lobes are described in the frontal plane. This presentation indicates the principal rules of cerebral lobes'identification, the basis of variability perception and the localization of small lesions allowing an accurate correlation with clinical findings and a suitable therapeutic procedure.

We report a case of an asymptomatic vasospasm with a focal, reversible apparent diffusion coefficient (ADC) decrease after a middle cerebral artery aneurysm rupture. This isolated decrease of ADC has not yet been reported in this pathological situation. It could be interesting to predict the risk of ischemic delayed complications of vasospasm.

The aim of our study was to evidence the location of the cortical area triggered by visual memory tasks by he mean of functional magnetic resonance imaging examination (fMRI).Twelve healthy volunteers underwent fMRI examination on a 1.5 Tesla magnet with echoplanar imaging sequence during figurative and non-figurative memory tasks. An area was considered to be activated if at least 10 contiguous voxels activation was noted. Activated areas were defined for both tasks and the brain mapping was realized according to Talairach atlas.For all examinations a bilateral activity was evidenced (area 17 and 18). In addition, a frontal activation was also noted in 83% of the cases for both tasks. However, frontal activation was bilateral in 9/10 cases for the figurative task and 6/10 cases for the non-figurative task.FMRI was able to evidence activation of cerebral areas during visual memory tasks in all our study cases. Frontal activation was not discriminative of figurative or non figurative memory. This might be probably explain by inappropriate non-figurative tests. FMRI should allow a better knowledge of memory mechanisms as well as an enhancement of functional cerebral mapping before surgery.

3D angiography is a true technical revolution that allows improvement in the quality and safety of diagnostic and endovascular treatment procedures. 3D angiography images are obtained by reconstruction of a rotational angiography acquisition done on a C-arm (GE Medical Systems) spinning at 40 degrees per second. The carotid or vertebral selective injection of a total of 15 ml of non-ionic contrast media at 3 ml/sec over 5 seconds allows the selection of the "arterial phase". Four hundred sixty 3D angiographic studies were performed from December 1996 to September 1998 on 260 patients and have been analyzed in MIP (Maximum Intensity Projection) and SSD (Shaded Surface Display) views. The exploration of intracranial aneurysms is simplified and only requires, for each vascular axis, a biplane PA and Lateral run followed by a single rotational angiography run. The 3D angiography image is available on the workstation's screen (Advantage Workstation 3.1, GE Medical Systems) in less than 10 minutes after the acquisition of the rotational run. It therefore allows one to analyze, during the intervention, the aneurysm's angioarchitecture, in particular the neck, and select the best therapeutic technique. When endovascular treatment is the best indication, 3D angiography allows one to define the optimal angle of view and accurately select the microcoils dimensions. 3D angiography replaces the multiple oblique views that used to be required to analyze the complex aneurysms and therefore allows a reduction of the total contrast medium quantity, the patient X-ray dose and the length of the intervention time which is a safety factor. Also, in particular for complex cases, it brings additional elements complementing the results of standard 2D DSA and rotational angiograms. In the cervical vascular pathology, 3D angiography allows for a better assessment of the stenosis level and of dissection lesions. Our current research activities focus on the matching without stereotactic frame between 3D X-ray angiography and volumetric MR acquisition, which should allow us to improve the treatment of intracerebral arterio-venous malformations (AVMs).

Crack, the free-base form of cocaine, was introduced as an illicit street drug in 1986. Since then, we have noted a significant increase in acute gastroduodenal perforations. Between 1982 and 1986, we treated 11 patients with such perforations. This represents a constant occurrence rate of 6% of hospital admissions for peptic ulcer disease. Since 1986 we have treated 16 patients with gastroduodenal perforation, which yields an occurrence rate of 16%. Nine of the 16 patients had a close temporal relationship between the use of crack and the onset of their perforation. This group was younger and disproportionately comprised of male patients. These findings led us to believe that there may be a pathogenic relationship between the use of crack and acute gastroduodenal perforation, and the clinician should be aware of the various potential complications of this new drug. This relationship also raises questions about the exact pathophysiology of peptic ulcer disease.

The spinal canal is an uncommon site for abscess formation resulting from bloodstream disseminated infection. Prognosis is often unfavorable. Rapid treatment is essential for satisfactory neurological recovery. Abscesses within the spinal canal are thus diagnostic and therapeutic emergencies. The neuro-infectious and inflammatory manifestations and laboratory findings vary considerably and are insufficient for diagnosis. MRI plays a decisive role. The most commonly reported signs are the presence of an intramedullary collection giving a low-intensity signal on T1-weighted images and a high-intensity signal on T2-weighted images with peripheral contrast uptake and generally extended adjacent medullary edema. We report here five cases of spinal canal abscesses diagnoses with MRI at different stages of development (pre-suppurative myelitis in two cases, constituted abscess in three cases). For each case we reviewed the clinical course and describe the details of the imaging findings. In our series, the collected abscesses presented as round lesions within the canal with contrast uptake. It is noteworthy that the periependymal gray matter adjacent to the lesion also took up the contrast agent in all patients with a collected abscess. This sign has not been described previously and appears to be a going argument orienting the diagnosis towards an infectious rather than tumoral formation.

This article describes a health promotion project for teens in a rural francophone community in Northern Ontario. A planning committee of two community health nurses and eight teenagers developed, implemented and evaluated the project. Based on teen interest generated in the community, the committee planned a youth snowmobile day to help identify and define the teenagers' particular health needs. The aim was to facilitate youth participation at every step of the project, from needs assessment to follow-up, and encourage them to explore, with their peers, ways to improve their health. A qualitative research approach was used to study and document the event. A total of 48 girls and boys in the 13-19 age group took part. Stopovers were held at various inns for group discussions on predetermined topics. Study results indicate that when power is shared with teenagers, important lessons are learned by both parties. In such a partnership, nurses need to use more than the educational approach to interventions. Their role as community development facilitators is highlighted, as well as their need to develop novel and unique approaches for dealing with teenagers.

Various therapeutic strategies have been recently proposed to prevent the vasospasm after subarachnoid haemorrhage, and to avoid its clinical consequences. Despite these progresses, mortality and morbidity of delayed ischaemic consequences of vasospasm remain important. Two endovascular treatments have been proposed. The successful use of transluminal angioplasty for vasospasm was first reported by Zubkov in 1984. Transluminal angioplasty is very effective with clinical improvement when the treatment is undertaken without delay after the onset of symptoms. Limitations of this technique are the inaccessibility of distal arteries and the risks (vascular rupture or occlusion). More recently, to overcome these limitations, a selective intraarterial infusion of papaverine has been proposed. These infusions are less risky and can be employed in distal vasospasm. However, clinical results seem to be less favourable and often transient. These two techniques are still used with slightly different indications. According to our experience, it seems reasonable to reserve transluminal angioplasty for symptomatic vasospasm, associated with papaverine or not, and to use papaverine alone in all other cases.

Traditionally the aneurysms of the circle of Willis have been an indication for neurosurgery. New technologies of endovascular treatment with electrically detachable coils resulted in a different therapeutical concept since four years. A series including 140 patients has been treated in our institution from 1 January 1992 to 31 December 1994, 94 of them presenting with a subarachnoid haemorrhage. Out of these 140 patients, 84 were treated with surgery, 51 with the endovascular technique, five with surgery after incomplete or unsuccessful endovascular treatment. Surgery was indicated in patients presenting early after bleeding, devoid of vasospasm, with a favourable Hunt and Hess grading and in aneurysms located in the anterior part of the circle of Willis. Endovascular treatment was indicated in patients admitted with delay, with severe vasospasm, a poor Hunt and Hess grading and in all aneurysms of the vertebrobasilar arterial network. Age was of less importance in comparison to the status of the vessels for selection of the method of treatment. Giant aneurysms are difficult to treat as surgery is faced with the size of the aneurysmal itself and endovascular technique with the width of the aneurysmal neck.

Major improvements have been achieved in endovascular treatment of intracranial aneurysms during the last twenty years. Initial techniques of selective balloon occlusion were progressively replaced by the packing of the aneurysmal pouch with very small and soft metallic devices, named coils, with controlled detachment. In some rare cases, balloon occlusion is still used in order to occlude the parent vessel or to reverse the flow, especially in the vertebro-basilar system. Essential aims for the anaesthesiologist include: complete immobility of the patient throughout the endovascular procedure, systemic anticoagulation in order to avoid any thromboembolic complication during and after treatment, prevention and/or treatment of vasospasm, precise evaluation of fluid balance during the procedure. Our experience is based on 145 aneurysms in 135 patients, treated by endovascular route; 91 (63%) of them were revealed by a subarachnoid haemorrhage (SAH). Their main locations were: the carotid siphon (33.1%), the anterior communicating artery (19.3%), the basilar artery (17.2%) and the middle cerebral artery (17.2%). Thirty-seven of these aneurysms (25.5%) were very small in size with a diameter less than 4 mm. Total or sub-total (more than 90%) occlusion was achieved in 141 aneurysms (90.3%). Thromboembolic complications occurred in eight patients (5.9%), neurological sequelae in one. Other treatment-related complications included the migration of a coil outside the aneurysm in six cases (4.4%) without neurological deficit in one and five ruptures of the aneurysm (3.7%) during the procedure with one lethal issue due to the spontaneous bleeding of a controlateral arterio-venous malformation. Thirteen patients died (9.6%). The cause of the death was related on the initial SAH in 11 of them. The two others were both due to rupture: of a second untreated aneurysm in one case and of an associated arteriovenous malformation in the second one. At present the main indications of endovascular treatment are poor or non indications for neurosurgery. Due to the quality of results, endovascular therapy will be more and more used in case of ruptured or non ruptured aneurysms.

Correlation of myelin-stained or cryotomic sections of human brain with inversion-recovery MR images can display the cerebral commissures as white-matter tracts (in hypersignal on MRI), crossing the mid-line. MRI shows routinely in three orthogonal planes a) the corpus callosum stretched above the supra-tentorial ventricles, it's four portions (rostrum, genu, body and splenium) and connections with the Deep Grey Nuclei b) the fornix, intralimbic commissure joining anteriorly the mammillary bodies (through it's columns) to the alveus posteriorly and inferiorly (via it's two crura), arcing around the thalamus and lying over the hippocampus and the dentate gyrus as shown on the frontal sections c) the anterior commissure, white-matter tract connecting the two temporal lobes. In axial view, the anterior commissure has the shape of bicycle handlebars, coursing posteriorly, inferiorly and laterally behind the head of the caudate nucleus and passes into the lateral nucleus of the globus pallidus into the inferior and middle temporal gyri. Because the anterior commissure is easily recognisable in all planes, it's appears to be a important landmark for identification of the lateral and medial nuclei of the globus pallidus on axial and sagittal planes d) at least, the posterior commissure, anterior margin of the pineal region, closely related to the superior colliculi, acquire a major importance in the AC-PC line delineation becoming a reference landmark for stereotatical procedures.

Narcolepsy associated with localized brain lesions is rare, and few reports of well-documented cases have been published. We describe the case of a 20-year-old male (HLA DQw1 negative) who fulfilled clinical and polygraphic criteria of symptomatic narcolepsy. Narcolepsy in this patient was associated with an arteriovenous malformation involving the structures around the third ventricle. Clinical symptoms improved after embolization and radiosurgery. These findings support the hypothesis that lesions in the vicinity of the third ventricle can cause symptomatic narcolepsy.

According to many ethical and humanitarian arguments, the diagnosis of "brain death" is more and more an emergency. The forensic criteria include abolition of consciousness, abolition of brain stem reflexes, abolition of spontaneous breathing joined to electrocerebral silence. However using EEG criteria of electrical silence may be unreliable because of technical artefacts or depressed electrical activity due to drug intoxication and hypothermia. Venous angiography was used in 125 cases: our experience proves reliability and efficiency of angiographic criteria for diagnosis of brain death. For organ transplant, it is better to be as fast as possible: transplanted organ will be better and it reduces the cost of a long useless intensive care. When it is necessary, we suggest to allow the choice between EEG and angiography.

Between April 1986 and April 1991, seven cases of meningeal haemorrhage consecutive to dissection of the 4th segment of a vertebral artery were observed at the Neuroradiology Department of the Nancy University Hospital. Four of the 7 patients were men, and 3 were women; mean age varied from 45 to 61 years. The clinical presentation was not suggestive, except in one case where the haemorrhagic episode was associated with Wallenberg's syndrome, pointing to the aetiological diagnosis. The outcome was variable. Two patients died of early complications of the haemorrhage which occurred before treatment could be given. In 2 others patients treated with antiplatelet agents the outcome was favourable; however, at angiography the lesions regressed in one of these two patients, but they progressed in the other with formation of a false aneurysm. The remaining 3 patients were treated by endovascular occlusion of the lesion-bearing vessel: one died of complications of a haemorrhage-induced vasospasm; the other two are symptomless after a 2 to 6 months follow-up.

The conserved DAF-16/FOXO transcription factors and SIR-2.1/SIRT1 deacetylases are critical for diverse biological processes, particularly longevity and stress response; and complex regulation of DAF-16/FOXO by SIR-2.1/SIRT1 is central to appropriate biological outcomes. Caenorhabditis elegans Host Cell Factor 1 (HCF-1) is a longevity determinant previously shown to act as a co-repressor of DAF-16. We report here that HCF-1 represents an integral player in the regulatory loop linking SIR-2.1/SIRT1 and DAF-16/FOXO in both worms and mammals. Genetic analyses showed that hcf-1 acts downstream of sir-2.1 to influence lifespan and oxidative stress response in C. elegans. Gene expression profiling revealed a striking 80% overlap between the DAF-16 target genes responsive to hcf-1 mutation and sir-2.1 overexpression. Subsequent GO-term analyses of HCF-1 and SIR-2.1-coregulated DAF-16 targets suggested that HCF-1 and SIR-2.1 together regulate specific aspects of DAF-16-mediated transcription particularly important for aging and stress responses. Analogous to its role in regulating DAF-16/SIR-2.1 target genes in C. elegans, the mammalian HCF-1 also repressed the expression of several FOXO/SIRT1 target genes. Protein–protein association studies demonstrated that SIR-2.1/SIRT1 and HCF-1 form protein complexes in worms and mammalian cells, highlighting the conservation of their regulatory relationship. Our findings uncover a conserved interaction between the key longevity determinants SIR-2.1/SIRT1 and HCF-1, and they provide new insights into the complex regulation of FOXO proteins., Author Summary The nematode C. elegans has been instrumental in identifying and characterizing genetic components that influence aging. Studies in worms have been successfully extended to complex mammalian organisms allowing for the identification of genetic factors that impact longevity in mammals. DAF-16/FOXO transcription factors are among the best characterized longevity factors, and their increased activity leads to a longer lifespan and improved stress resistance in many organisms. Elucidating how the activities of DAF-16/FOXO are regulated will provide new insights into the basic biology of aging and will aid future therapeutic developments aiming to improve healthy aging and alleviate age-related diseases in humans. We utilized both C. elegans and mammalian cell culture systems to dissect the functional and molecular interactions between two important DAF-16 regulators, HCF-1 and SIR-2.1/SIRT1. We demonstrated that HCF-1 and SIR-2.1/SIRT1 physically associate and antagonize each other to properly regulate DAF-16/FOXO-mediated expression of genes important for longevity and stress response. We further showed that the functional relationships among these three proteins are conserved in mammals. Our work implicates HCF-1 as an important player in the regulation of FOXO by SIRT1, and thereby a potential longevity determinant in humans, and prompts further characterization of HCF-1's functions in aging and age-related pathologies.

A technique for electrocardiographic (ECG) guided percutaneous placement of central venous catheters (CVC) was studied in a prospective, randomized manner. In 34 patients, 51 ECG guided percutaneous CVC were compared with 29 blind percutaneous CVC in 23 patients. Thirty-nine percent of CVC placements were changes over a guide wire. Ideal catheter tip location at the atriocaval junction was achieved in 96 percent of the patients in the study versus 59 percent of those in the control group (p less than 0.001). In addition, we report 25 patients with open placement of CVC using intraoperative ECG guidance and fluoroscopic confirmation. Ideal location of the catheter tip was achieved in 100 percent of these patients. ECG guided CVC placement using the technique described herein obviates the need for catheter repositioning, repeat roentgenographic studies and intraoperative fluoroscopic imaging, along with the attendant costs and radiation exposure to staff and patient. Aberrant catheter tip placement and the associated morbidity are also eliminated.

Vasospasm (V.S.) transluminal angiographic treatment (T.L.A.) is recommended in case of symptomatic V.S. before or after surgery. V.S. diagnosis and follow up after T.L.A. rely on clinical and transcranial doppler (T.C.D.) data. Before T.L.A. angiography (A degrees) demonstrates V.S. degree and location. T.L.A. technic is described. The authors report 14 cases of T.L.A. (7 before and 7 after surgery). Before surgery in 4 cases patients exhibited ischemic symptoms from V.S.: 2 died (one from reanimation problems the other from a new hemorrhage). After surgery of 7 patients one died from artery rupture, one from extra-neurologic complication. T.C.D. capacity to follow up V.S. is emphasized. As soon as T.L.A. is performed the mean cerebral blood flow (C.B.F.) decreases (100 cm/s) and does not increase anymore. At the level of non dilated arterial segments V.S. may increase after T.L.A.: it is then recommended to dilate all the spastic arteries, as far as it is possible. After T.L.A. C.B.F. may decrease in arteries far from the dilated ones probably because arterial supplies are no more necessary.

MR Imaging has become the procedure of choice for the exploration of the pituitary region. MR contrast resolution is far better than the finest CT examination, especially concerning the microadenomas and the neurohypophysis. The present paper concerns, at first the major principles of magnetic resonance imaging, its application for the study of the pituitary region including the use of contrast agent (Gadolinium). Lastly, MR anatomy and physiological variations are presented.

The cervical spine is rarely involved in scleroderma. The lesions reported here consisted of osteolysis of the posterior arches disturbing vertebral statics, and exuberant calcifications responsible for spinal cord compression by stenosis of the vertebral canal.

Angioplasty of vascular spasm (VS), related to subarachnoid hemorrhage (SAH) has been recently introduced to the medical field. The authors report 5 cases treated by this mean in the postoperative period. These patients were all symptomatic from their VS inspite of early surgery and of the preventive treatment by Nimodipine. In all cases, obtained increase in the caliber of the spastic vessels was followed by a rapid clinical improvement coupled with a significant decline of the flow rates as confirmed by transcranial Doppler (TCD). No recurrence of VS has been observed. This technique appears quite effective provided that it is performed as early as the clinical symptoms come out in correlation with important acceleration of flow rates on TCD.

A 41 years old patient on hemodialysis for 17 years with a clinical and radiological picture of osteoarticular beta 2 microglobulin amyloidosis, is presented. The patient had skeletal involvements, included cystic lesions of the left hip and both humeral heads and a C5/C6 spondylarthropathy. She had also associated carpal tunnel syndrome. Radiological exploration of the atlanto-occipital articulation demonstrated destructive changes. Histology documented osseous and periarticular deposition of beta 2 microglobulin derived amyloid. This is an unusual location of destructive spondylarthropathy in a patient on chronic hemodialysis.

Among the 84 intracranial dural fistulae treated in the Neuroradiology department of the University Hospital Centre of Nancy between August 1983 and April 1990, 10 (11.9%) were located on the tentorium cerebelli. The patients were 7 men and 3 women aged from 41 to 61 years at the time of diagnosis. All tentorial dural fistulae showed an exclusively cortical drainage, and only one of them was associated with probable thrombosis of a major sinus. Nine patients presented with at least one episode of neurological deficit (including 2 with progressive ascending myelopathy) associated with a cerebro-meningeal haemorrhage in 6 cases. In all patients the initial treatment was an endovascular one, subsequently reinforced by surgery in 2 patients. In every case the clinical condition was improved or stabilized and no recurrent haemorrhage was observed, but radioanatomical cure was obtained in only 3 patients: 1 treated by the endovascular route and 2 by embolization combined with surgery. The anatomical, physiopathological and clinical aspects of these particular fistulae and the different possible therapeutic approaches are discussed.

The lesions of the cerebral white matter which characterize Pelizaeus-Merzbacher disease are classically observed at pathological examination. An early diagnosis can now be obtained by magnetic resonance imaging (MRI). In an eutrophic first son born at term, stridor, nystagmus-like eye movements and axial hypotonia were noted immediately after birth and pyramidal signs appeared at 2 months, the only extra-clinical finding at that age being prolonged latencies of evoked visual potentials. An MRI exploration, performed at 3 months, showed that compared with the grey matter the white matter emitted a low-intensity signal on the T1-weighted sequence and a high-intensity signal on the T2-weighted sequence (signal inversion), such diffuse and symmetrical MRI abnormalities being typical of dysmyelination. When combined with suggestive clinical signs, these abnormalities confirm the diagnosis of Pelizaeus-Merzbacher disease, even in the absence of a familial history, and make it possible to warn the parents of the poor prognosis and the risk of recurrence among future sons.

Eleven farmers were monitored for dermal and respiratory exposure to terbufos [phosphorodithioic acid, S-(tert-butylthio) methyl O,O-diethyl ester] during a typical working day while planting corn and applying COUNTER® 15-G systemic insecticide-nematicide. The average estimated dermal exposure was 72 Μg/hr while the estimated respiratory exposure was 11 Μg/hr. The results of urinary alkyl phosphate analyses were all negative showing no detectable absorption of terbufos. Plasma and red blood cell cholinesterase values of exposed farmers showed no significant difference in activity when compared to either preexposure or control values indicating no adverse physiological effects from the exposure. Based on these results, the use of COUNTER 15-G does not present a significant hazard, in terms of acute toxicity, to farmers using this product for the control of corn insects.