GRaNIE and GRaNPA: inference and evaluation of enhancer-mediated gene regulatory networks

Enhancers play a vital role in gene regulation and are critical in mediating the impact of noncoding genetic variants associated with complex traits. Enhancer activity is a cell-type-specific process regulated by transcription factors (TFs), epigenetic mechanisms and genetic variants. Despite the strong mechanistic link between TFs and enhancers, we currently lack a framework for jointly analysing them in cell-type-specific gene regulatory networks (GRN). Equally important, we lack an unbiased way of assessing the biological significance of inferred GRNs since no complete ground truth exists. To address these gaps, we present GRaNIE (Gene Regulatory Network Inference including Enhancers) and GRaNPA (Gene Regulatory Network Performance Analysis). GRaNIE (https://git.embl.de/grp-zaugg/GRaNIE) builds enhancer-mediated GRNs based on covariation of chromatin accessibility and RNA-seq across samples (e.g. individuals), while GRaNPA (https://git.embl.de/grp-zaugg/GRaNPA) assesses the performance of GRNs for predicting cell-type-specific differential expression. We demonstrate their power by investigating gene regulatory mechanisms underlying the response of macrophages to infection, cancer and common genetic traits including autoimmune diseases. Finally, our methods identify the TF PURA as a putative regulator of pro-inflammatory macrophage polarisation.

SARS-CoV-2 historical global testing and genomic variability

The world has been dealing with the SARS-COV-2 pandemic since December 2019 and a lot of effort has focused on tracking the spread of the virus by gathering information regarding testing statistics and generating viral genomic sequences. Unfortunately, there is neither a single comprehensive resource with global historical testing data nor a centralized database with summary statistics of the identified genomic variants. We merged different pre-aggregated historical testing data and complemented them with our manually extracted ones, which consist of 6852 historical test statistics from 76 countries/states unreported in any other dataset, at the date of submission, making our dataset the most comprehensive to date. We also analyzed all publicly deposited SARS-CoV-2 genomic sequences in GISAID and annotated their variants. Both datasets can be accessed through our interactive dashboard which also provides important insights on different outbreak trends across countries and states. The dashboard is available at https://bioinfo.lau.edu.lb/gkhazen/covid19. A daily updated version of the datasets can be downloaded from github.com/KhazenLab/covid19-data.

Identification of transmission chains and clusters associated with COVID-19 in Tunisia

BACKGROUND

The aim of this study was to characterize the transmission chains and clusters of COVID-19 infection in Tunisia.

METHODS

All cases were confirmed by Reverse Transcriptase Polymerase Chain Reaction of a nasopharyngeal specimen. Contact tracing is undertaken for all confirmed cases in order to identify close contacts that will be systematically screened and quarantined. Transmission chains were identified based on field investigation, contact tracing, results of screening tests and by assessing all probable mode of transmission and interactions.

RESULTS

As of May 18, 2020, 656 cases out of a total of 1043 confirmed cases of Coronavirus disease 2019 belong to 127 transmission chains identified during the epidemic (mean age 42.36 years, Standard deviation 19.56 and sex ratio 0.86). The virus transmission is the most concentrated in the governorate of Tunis (31.5%), Ariana (10.2%) and Ben Arous (10.2%). Virus transmission occurred 50 times (9.72% of secondary transmission events) between two different governorates. A maximum of seven generations of secondary infection was identified, whereas 62% of these secondary infections belong the first generation. A total of 11 "super spreader" cases were identified in this investigation. Four large clusters have been identified. The evolution of secondary cases highlighted two peaks: one in 2nd April and a second in 16 th April whereas imported cases caused local transmission of virus during the early phase of the epidemic.

CONCLUSION

Correct contact tracing and early active case finding is useful to identify transmission chains and source of infection in order to contain the widespread transmission in the community.

Expanded genome-wide comparisons give novel insights into population structure and genetic heterogeneity of Leishmania tropica complex

Leishmania tropica is one of the main causative agents of cutaneous leishmaniasis (CL). Population structures of L. tropica appear to be genetically highly diverse. However, the relationship between L. tropica strains genomic diversity, protein coding gene evolution and biogeography are still poorly understood. In this study, we sequenced the genomes of three new clinical L. tropica isolates, two derived from a recent outbreak of CL in camps hosting Syrian refugees in Lebanon and one historical isolate from Azerbaijan to further refine comparative genome analyses. In silico multilocus microsatellite typing (MLMT) was performed to integrate the current diversity of genome sequence data in the wider available MLMT genetic population framework. Single nucleotide polymorphism (SNPs), gene copy number variations (CNVs) and chromosome ploidy were investigated across the available 18 L. tropica genomes with a main focus on protein coding genes. MLMT divided the strains in three populations that broadly correlated with their geographical distribution but not populations defined by SNPs. Unique SNPs profiles divided the 18 strains into five populations based on principal component analysis. Gene ontology enrichment analysis of the protein coding genes with population specific SNPs profiles revealed various biological processes, including iron acquisition, sterols synthesis and drug resistance. This study further highlights the complex links between L. tropica important genomic heterogeneity and the parasite broad geographic distribution. Unique sequence features in protein coding genes identified in distinct populations reveal potential novel markers that could be exploited for the development of more accurate typing schemes to further improve our knowledge of the evolution and epidemiology of the parasite as well as highlighting protein variants of potential functional importance underlying L. tropica specific biology.

Neurosarcoidosis presenting as trigeminal nevralgia: a case report and review of the literature

Sarcoidosis is a granulomatous disease that can present systemically, but primarily has pulmonary manifestations. It is reported across all races, but has a higher incidence among African Americans. Neurological involvement in sarcoidosis is rare, with cranial nerve seven being the most commonly reported neurological finding. Trigeminal neuralgia, as presented in this case, is very rare. A 38-year-old African American female, with history of refractory trigeminal neuralgia, cutaneous sarcoidosis, and an extensive psychiatric history, presented to the hospital for fifth cranial nerve decompression. She had failed medical therapy and gamma knife therapy. Prior to surgery, magnetic resonance imaging (MRI) revealed a mass of 1.5 cm x 0.6 cm x 1.1 cm in the left Meckel's cave, which, when compared with prior imaging, was not present. A partial craniotomy was done to excise the mass. Frozen pathological sections showed granulomatous inflammation consistent with sarcoidosis. Stains for acid fast bacilli and fungi remained negative. Quantiferon Gold and HIV serum studies were negative. High resolution computed tomography (CT) scan the chest showed patchy infiltrates in the lungs that presented as chronic interstitial lung disease. The patient's neurological symptoms resolved after surgical resection. She was dismissed home on a tapering dose of dexamethasone and follow-up with a rheumatologist. This case illustrates that when a patient with sarcoidosis presents with neurological symptoms, neurosarcoid should be considered. Most cases are diagnosed during autopsies. Recognizing and correctly diagnosing neurosarcoid leads to proper treatment and decreased morbidity in patients.

Mycobacterium avium-intracellulare presenting as an endobronchial tumour due to immune reconstitution inflammatory syndrome

Mycobacterium avium-intracellulare (MAI) infection in an HIV-positive patient can present shortly after starting antiretroviral therapy, as a result of immune reconstitution inflammatory syndrome (IRIS). We report a case of a 33-year-old woman where MAI presented as an endobronchial tumour due to IRIS. She responded well to standard anti-MAI treatment (rifamycins, macrolide and ethambutol).

Investigation of a cluster of syphilis among heterosexuals in an English town

A cluster of five (3 primary and 2 early latent) cases of syphilis were identified in young heterosexuals in the east of England. Three were symptomatic at presentation. No further cases linked to this cluster have been diagnosed since June 2010. Effective partner notification is key to the identification and treatment of infected contacts.

The modic vertebral endplate and marrow changes: pathologic significance and relation to low back pain and segmental instability of the lumbar spine

Two decades following their description, the significance of Modic vertebral endplate and marrow changes remains a matter of debate. These changes are closely related to the normal degenerative process affecting the lumbar spine, and their prevalence increases with age. However, the exact pathogenesis underlying these changes and their relation to segmental instability of the lumbar spine and to low back pain remain unclear. In this paper, we review the literature relevant to this topic and discuss the currently available evidence regarding the pathologic and clinical significance of Modic changes.

Acute Korsakoff-like amnestic syndrome resulting from left thalamic infarction following a right hippocampal hemorrhage

Korsakoff-like amnestic syndromes have been rarely described following structural lesions of the central nervous system. In this report, we describe a case of acute Korsakoff-like syndrome resulting from the combination of a left anteromedian thalamic infarct and a right hippocampal hemorrhage. We also review the literature relevant to the neuropathology and pathophysiology of Korsakoff syndrome and anterograde amnesia.

Hématome intracérébral spontané du sujet jeune

INTRODUCTION

Hemorrhagic stroke is uncommon in young patients. The etiologic spectrum is very wide in the literature. The purpose of this study was to determine the range of etiology in a group of patients completely investigated and to study the relation with a history of high blood pressure.

PATIENTS AND METHODS

We reviewed study database, clinical and diagnostic records of 130 patients identified in a population based study, aged 18 to 55 years presenting with hemorrhagic stroke. There were divided into two groups: 67 patients treated at Hotel-Dieu Hospital in Beirut, Lebanon, and 63 patients reviewed at Yale New Haven Hospital, Connecticut, USA. Patients presenting with selective subarachnoidal or intraventricular hemorrhage were excluded. Diagnostic evaluation was assessed for completeness (based on prospectively articulated evidence based criteria) and for identifiable etiology of hemorrhagic stroke and its relation to high blood pressure.

RESULTS

There were 84 cases (64%) with complete diagnostic workup. The most common cause of incomplete investigations in remaining cases was death, poor neurological condition and incomplete follow up. Hematoma was superficially located (lobar) in 59.2%, deep seated (thalamo-capsulo-lenticular) in 26%, within the brain stem in 8.7% and cerebellar in 6.1%. An etiology was established in 70.4% of cases (pial AVM 16.7%, aneurysms 15.5%, hematological disorders 13%, cavernous malformations 10.7%, tumors 4.8%, bleeding within ischemic area 3.8%, vasculitis 2.3%, venous thrombosis 1.2% and venous angioma 1.2%. 29.6% of patients remained with undetermined etiology despite complete investigations. In a subgroup of 45 patients, a history of high blood pressure was found in 46.7%. In this cohort, an underlying etiology was established in 71% of cases.

CONCLUSION

Complete investigation can establish an etiology in 70% of young patients who survived hemorrhagic stroke, independently from the presence of a history of high blood pressure.

Hydrotel, un modèle hydrologique distribué pouvant bénéficier des données fournies par la télédétection et les systèmes d'information géographique

Les processus hydrologiques variant dans l'espace et dans le temps en fonction de la variabilité spatio-temporelle des entrées météorologiques et de l'occupation du sol ainsi que de la variabilité spatiale de la topographie et de la nature du terrain, un modèle conçu pour bénéficier des données provenant de la télédétection et des SIG a été développé. Les principaux objectifs poursuivis étaient: l'application au plus grand nombre de bassins possible, une sélection d'algorithmes permettant de tenir compte des données disponibles, un minimum d'étalonnage, la facilité de transfert d'un bassin à l'autre, la programmation des algorithmes sur micro-ordinateur avec une interface très conviviale.

La structure d'écoulement à l'intérieur d'un bassin versant est obtenue de manière informatisée à partir d'une discrétisation des altitudes rencontrées dans la zone d'intérêt, en mailles carrées de dimensions données, d'où l'on tire les pentes et les orientations de chaque maille, puis le bassin versant en amont de la maille identifiée comme exutoire, le réseau hydrographique, les sous-bassins versants et, finalement, les unités hydrologiques relativement homogènes (UHRH), définies sur la base de ces sous-bassins, en les regroupant ou les divisant au besoin. Un logiciel spécifique pour ce faire a été développé: PHYSITEL.

Selon la conception très modulaire adoptée pour HYDROTEL, chaque sous-modèle offre généralement plus d'une option de simulation, afin de tenir compte des données disponibles sur le bassin versant traité. Les simulations peuvent être réalisées en considérant comme unité de simulation du bilan hydrologique vertical les mailles originales constituant le bassin ou les UHRH.

Des exemples de simulation des débits à l'aide du modèle HYDROTEL sur divers bassins versants situés au Canada (Québec, Ontario, Colombie-Britannique) et dans le sud de la France sont présentés.

Ces simulations indiquent que les différents algorithmes du modèle réagissent bien et qu'il est possible de considérer son application sur des bassins très divers situés sous des conditions climatiques variées. Des tests plus poussés sont en cours afin de mieux cerner la sensibilité des divers algorithmes aux données d'entrée ainsi que leur interchangeabilité.

Changes in phosphorylation of the NMDA receptor in the rat hippocampus induced by status epilepticus

Systemic administration of pilocarpine preceded by lithium induces status epilepticus (SE) that results in neurodegeneration and may lead to the development of spontaneous recurrent seizures. We investigated the effect of Li/pilocarpine-induced SE on phosphorylation of the NMDA receptor in rat hippocampus. Phosphorylation of NR1 by PKC on Ser890 was decreased to 45% of control values immediately following 1 h of SE. During the first 3 h following the termination of SE, phosphorylation of Ser890 increased 4-fold before declining to control values by 24 h. Phosphorylation of NR1 by PKA was also depressed relative to controls immediately following SE and transiently increased above control values upon the termination of SE. SE was accompanied by a general increase in tyrosine phosphorylation of hippocampal proteins that lasted for several hours following the termination of seizures. Tyrosine phosphorylation of the NR2A and NR2B subunits of the NMDAR increased 3-4-fold over control values during SE, continued to increase during the first hour following SE and then declined to control levels by 24 h. SE resulted in the activation of Src and Pyk2 associated with the postsynaptic apparatus, suggesting a role for these enzymes in the SE-induced increase in tyrosine phosphorylation. Changes in phosphorylation of the NMDA receptor may play a role in the pathophysiological consequences of SE.

Neurocytome central

We report four cases of central neurocytoma we operated on at our institution, between 1994 and 2002. This uncommon lesion occurred in young patients, was located in the lateral ventricules and was revealed by signs of intracranial hypertension. The tumor was totally removed in three cases and subtotally in one. Immunohistochemistry provided useful information to distinguish neurocytoma from other nervous system tumors. Prognosis was excellent in two patients. One patient developed tumor recurrence seven years after surgery, without any progression on further follow up evaluation. In the last patient, the tumor showed a more aggressive progression requiring the adjunction of radiosurgery.

[Anterior cervical discectomy with or without bone graft placement in the treatment of cervical radiculopathy. Long-term results]

BACKGROUND AND PURPOSE

Anterior approach for cervical radiculopathy is a frequently performed operation in neurosurgery. The goal of this study is to evaluate the short and long-term results of anterior cervical discectomy with and without fusion.

METHODS

Between 1984 and 1999, we operated on 101 patients presenting with cervical radiculopathy by an anterior approach. The operation consisted of one-level discectomy in 74 cases, two-level discectomy in 25 cases and three-level discectomy in 2 cases. Eighty-four out of 130 levels operated on were fused. Evaluation was done following a consultation with dynamic cervical X-rays and by telephone using a detailed questionnaire. Follow-up was obtained in 91 cases with a mean of 54 months in fused patients, and a mean of 45 months in the non-fused patients.

RESULTS

Post-operative results were good in 95% in the 2 groups of patients. We encountered 8 complications, all in patients operated with bone graft placement. Five patients were reoperated on at an adjacent level, 4 being fused previously.

CONCLUSIONS

The 2 techniques are comparable in term of goods results at short and long-term follow-up. Anterior discectomy without fusion is associated with less complications, less post-operative pain, and less operative time cost.

Herbicide transport to surface waters at field and watershed scales in a Mediterranean vineyard area

The contamination of soil and runoff water by two herbicides, diuron [N'-(3,4-dichlorphenyl)-N,N-dimethylurea] and simazine (6-chloro-N,N'-diethyl-1,3,5-triazine-2,4-diamine), were monitored on two fields, one no-till and one tilled. Experiments were carried out in a 91.4-ha watershed in southern France during the 1997 growing season in order to understand the patterns of pesticide transport from field to watershed. The persistence of the herbicides in soil was prolonged due to the climatic conditions. At the field scale, annual herbicide loads were due to overland flow and amounted to 65.6 and 6.3 g ha(-1) of diuron for the no-till and tilled field, respectively, and to 29.6 and 1.83 g ha(-1) of simazine. Maximum herbicide concentrations exceeded 580 microg L(-1) during the first storm event after application and decreased thereafter but remained for 8 mo above 0.1 microg L(-1). At the watershed outlet, estimated annual loads amounted to 4.12 g ha(-1) of diuron and 0.56 g ha(-1) of simazine. Among them, 96% of the losses in diuron and 83% of those in simazine were caused by the fast transmission through the network of ditches of the overland flow exiting the fields. For diuron, which was sprayed over most of the vineyards, its in-stream concentrations during storm flow were close to those at the outlet of the fields. The herbicide loads in baseflow were smaller than 0.2 g ha(-1). The patterns of the loads at the field and watershed scales suggested that a major part of the herbicides leaving the fields reinfiltrated to the ground water by seepage through the ditches, and was there degraded or adsorbed.

[Hemorrhage after radiosurgery of cerebral arteriovenous malformations]

BACKGROUND AND PURPOSE

Obliteration is progressive after radiosurgery of cerebral arteriovenous malformations. Thus the hemorrhage risk still remains until obliteration. Purposes of this study are to appreciate severity of post-radiosurgery hemorrhages, actuarial risk of hemorrhage and parameters associated with it.

PATIENTS

and method. Over 705 patients treated, 46 (6.5%) had one or several hemorrhages. Clinical, anatomic, dosimetric parameters and obliteration rates before hemorrhage were studied. Then, actuarial risks per patient and per hemorrhage were calculated. Correlations between parameters and risk were searched by uni and multivariate analysis by drawing hemorrhage-free survival curves (limit-product Kaplan-Meier) and Cox model.

RESULTS

Except one pure ventricular hemorrhage causing death of one patient, only parenchymal hemorrhages were associated with morbidity (80% of cases with 45% of permanent deficits). Overall mortality rate by hemorrhage was 6.5%. Overall morbidity rate was 34.8% and 13.6% for permanent deficit. Mean obliteration rate before hemorrhage was 25%. Actuarial hemorrhage rate were 2.98% per patient and 3.24% per hemorrhage. Actuarial rate per patient increased from 1.46% first year to 5.95% 4(th) year after radiosurgery. Parameters correlated with hemorrhage risk were in univariate analysis size (p=0.01), Spetzler and Martin's grade (p<0.001), dose to reference isodose (p=0.03), Dmin (p=0.08), intra or paranidal aneurysms (p<0.001), and recoverage (p<0.001). After multivariate analysis, only intra or paranidal aneurysms, recovering and Dmin were significantly associated with hemorrhage-free survival after RS.

CONCLUSIONS

Post-radiosurgery hemorrhages are often sum of hemorrhage risk factors of the cerebral arteriovenous malformation and factors predicting low rate of obliteration. They can be in some cases foreseen but rarely avoided.

Subcranial fronto-orbito-nasal approach for ethmoidal cancers surgical techniques and results

BACKGROUND

The authors report their experience with the subfronto-orbito-nasal approach (SFON) for the treatment of 30 patients suffering from ethmoidal cancers over the past 3 years. The advantages and pitfalls of this technique are described and compared with other classic approaches.

METHODS

Among 156 patients suffering from ethmoidal cancers and treated between January 1984 and January 1998, 30 patients were operated on using the SFON approach during the past 3 years. There were 27 males and 3 females, ranging in age from 15 to 77 years. Histologic composition of the lesions was as follows: 15 adenocarcinomas, 6 esthesioneuroblastomas, 3 melanomas, 2 epidermoid carcinomas, 1 nondifferentiated carcinoma, 1 neuroendocrine carcinoma, 1 villous carcinoma, and 1 cystic adenoid carcinoma (cylindroma). According to the authors' classification, 7% were T1, 6% T2, 22% T3, 38.5% T4a, and 26.5% T4b. All patients were operated on through a SFON approach, followed by removal of the tumor and reconstruction of the skull base with a pericranial flap.

RESULTS

Since the mean follow-up was of short duration (12 months, ranging from 3 to 29 months), significant carcinologic results could not be obtained. However, a detailed analysis of the surgical procedure was performed. No patient died or had major complications related to the SFON approach. One cerebrospinal fluid (CSF) fistula and four oculomotricity dysfunctions were observed. Definitive anosmia was reported in all cases.

CONCLUSION

The advantages of the procedure include a wide exposure of the anterior skull base through a limited approach, the possibility of modifying the approach according to the size and location of the lesion, total resection of tumors, simplified skull base reconstruction technique, and reduction of postoperative confusion and hospital stay.

[Cervical myelopathy from ossification of the posterior longitudinal vertebral ligament. Report of 2 cases]

BACKGROUND AND PURPOSE

Cervical myelopathy due to an ossification of the posterior longitudinal ligament (OPLL) is a rare entity in western countries but frequent in Japan. We report on two Lebaneese patients aged 67 and 72 years respectively, who were twins and presented with OPLL.

METHODS

Diagnosis was made on myelography in the first case (1989) and on MRI of the cervical spine in the second case (1994).

RESULTS

A wide laminectomy was performed in the first case followed by a marked improvement. In the second case, corporectomy of the third, fourth and fifth vertebra with removal of the ligament followed by bone graft didn't improve the clinical symptoms.

CONCLUSION

The cause of OPLL remains unknown: genetic factors and metabolic abnormalities are outlined. Treatment options are discussed.

[Controversies in the management of operated pituitary macroadenomas]

BACKGROUND AND PURPOSE

Complete resection of a pituitary adenoma is feasible in almost 50 to 70% of cases. Dealing with the remnant is still controversial. Three positions can be discussed: second stage operation, radiation therapy, clinical and radiological follow-up.

METHODS

Among 108 pituitary macroadenomas operated on during the last 10 years, 54 patients (50%) with partially removed tumors were studied. Three cases best illustrating the evolution of these remnants are reported.

RESULTS

Late MRI performed 4 to 6 months postoperatively is more valuable than early MRI in the evaluation of these remnants, which can remain stable for a long period of time without any adjuvant treatment.

CONCLUSION

MRI should be performed 4 to 6 months postoperatively. Rather than performing radiation therapy systematically for asymptomatic patients, these patients should be followed up at regular intervals and treated only in case of regrowth of the tumor.

[Intracavernous extension of hypophyseal macroadenomas: infiltration or invagination?]

Frequency of intracavernous invasion by a pituitary adenoma varies from 9% to 40% depending on the publications. Without putting off the possibility of true intracavernous invasion, it seems less frequent than evocated on CT-Scan and/or MRI data. We studied 153 files of pituitary adenomas operated upon recently: 72 prolactinomas (47.3%), 30 GH-secreting adenomas (19.7%), 7 corticotrop adenomas (4.6%), 44 non secreting adenomas (28.3%). 108 patients (70.4%) harboured a macroadenoma (diameter > 10 mm). A suprasellar expansion was seen 90 times on CT-Scan and/or MRI views. 19 times (17.7% of macroadenomas, 12.5% of the whole series) MRI evocated an infiltration of one or both cavernous sinuses (CS). Such data were found 3 times before 1991, 16 times since 1991, i.e. since MRI is systematically performed preoperatively. Except in two patients who respectively presented with a large intraorbital or temporal expansion, we have not been able to confirm the reality of the intracavernous invasion. We think that most of CT-Scan or MRI data of so-called intracavernous invasion correspond in fact to a compression or to a fingerglove invagination of the medial wall of the CS. In fact, anatomical studies by Harris & Rhoton (1976) and by Taptas (1990) demonstrated that such an invagination of the medial wall exists in almost one third of normal pituitary glands. These data must bring up to much carefulness when considering a possible pathological CS invasion by a macroadenoma. Therefore, it should be thoroughly assessed with anatomoradiological and radio-surgical correlations.

[Value of increased MRI signal intensity in cervical arthrosis in myelopathies]

The case of 52 patients with cervical myelopathy were reviewed to determine whether a high signal intensity lesion present on T2 weighted spin echo imaging appears to be an important indicator for predicting prognosis. Preoperatively, there were areas of increased signal intensity in 23 patients. The lesion was clearly demonstrated on T1 weighted images in only one case. Postoperatively, MRI was performed in 9 cases, one showed decreased signal intensity compared to the preoperative levels, and 8 had no change. The pre and postoperative clinical conditions of the patients whose preoperative MR images showed areas of increase signal intensity were not worse than those patients who did not have these areas of increased signal intensity. The postoperative recovery of the eight patients who exhibited no change of the signal intensity was very satisfactory. The pathophysiology of such an abnormality is presumed to be related to edema, myelomalacia or gliosis. However, the presence of these areas of high signal intensity does not appear to be an indicator of a bad clinical prognosis.

[Cerebral metastasis disclosing osteosarcoma. Apropos of a case]

Brain metastasis from osteosarcoma is a rare entity. Almost 20 cases have been reported in the literature. We report an illustrative case of a 15 years old boy presenting with isolated brain metastase revealing a fibular osteosarcoma. Diagnostic methods and treatment modalities are discussed.

Overexpression of pp60c-src elicits invasive behavior in rat colon epithelial cells

BACKGROUND & AIMS

Src activation is reported as an early event found in preneoplastic colonic adenomas and in 70% of colon carcinomas. The aim of this study was to identify the biological consequences of c-src overexpression in rat colon epithelial cells.

METHODS

Introduction and overexpression of c-src in an immortalized rat colon epithelial cell line was achieved using lipofection. Transfectants were tested for changes in growth and cell behavior using different in vitro assay systems.

RESULTS

Colon epithelial cells overexpressing c-src showed the ability to form microcolonies in soft agar without acquiring tumorigenic potential. In in vitro assays, c-src transfectants displayed a gain of invasive potential through Matrigel without an accompanying change in migrational ability. No discernible qualitative changes were observed in the phosphotyrosyl protein profile between c-src and v-src transfectants. Assessment of the cadherin/catenin status in these cells revealed an intact, functional complex with no detectable tyrosine phosphorylation of different components of the complex.

CONCLUSIONS

Overexpression of c-src in an immortalized rat colon epithelial cell line does not elicit full neoplastic transformation but enhances anchorage-independent growth and confers invasion capability. Increased invasion through Matrigel was not linked to inactivation of the cadherin complex in c-src transfectants.

[Stereotaxic approach in deep cerebral lesions]

The authors report a retrospective study (April 92-April 95) of 60 CT guided stereotactic biopsies. The procedure offered accurate histological diagnosis in 56 cases. There were 38 glial tumors, the majority being of high grade (III-IV). Five abscesses were evacuated and medically treated. Complications occurred in 5% of cases. These results are compatible with those reported in the literature. The simplicity and accuracy of stereotactic procedure are confirmed, making it an imperative step in the management of intraxial space occupying lesion when surgical resection is negotiable. The other applications of the stereotactic procedure are exposed.

[Cervical extradural hematoma under coagulants. Review of etiologies and prognosis]

We report a case of cervical epidural hematoma associated with anticoagulant therapy in a 68 year-old man, who presented with tetraplegia. He was operated 12 hours after the onset. Three months later, he had recovered almost completely. The etiologies and prognosis of such lesions are reviewed.

[Thermocoagulation in the treatment of facial neuralgia. Preliminary results in 22 cases]

Twenty-two patients suffering from trigeminal neuralgia were treated by thermocoagulation from June 92 to June 94 at Hôtel-Dieu de France Hospital. Epidemiological, clinical, para-clinical elements and the therapeutic approach were studied. The results after a median follow-up of one year were satisfactory in twenty patients (90.9%) who became asymptomatic. No major complication was noticed. Two recurrences occurred however, one responded to another thermolesion. We propose and discuss this technic for the treatment of the trigeminal neuralgia.

Long-term stability of rapid palatal expander treatment and edgewise mechanotherapy

Previous studies on long-term stability of orthodontic treatment primarily have focused on the stability of the lower arch treated with edgewise appliances. The aim of this study was to evaluate the long-term stability of the upper and the lower dental arches of patients treated with a rapid palatal expander. The sample comprised of 165 dental casts randomly selected from patients who had been out of retention for 8 to 10 years at a mean age of 30 years. Measurements were made directly on dental casts obtained at the three time intervals: before treatment, after treatment, and after retention. Differences over time between the upper and the lower dental arches and between intervals were analyzed by a two-way multivariate analysis of variance (MANOVA) and post hoc Bonferroni t tests. Differences between after treatment and after retention were statistically significant (P < 0.006) for all except lower intermolar width. However, only for lower and upper arch lengths and perimeters were the differences greater than 2.0 mm. Treatment with the rapid palatal expander presented good stability for upper intercanine width, upper and lower intermolar widths and incisor irregularity. Lower intercanine, arch length, and perimeter presented poor stability.