IRM opératoire et chirurgie de l'épilepsie [Intraoperative MRI and epilepsy surgery].

Intraoperative imaging, in particular intraoperative MRI, is a developing area in neurosurgery and its role is currently being evaluated. Its role in epilepsy surgery has not been defined yet and its use has been limited. In our experience with a compact and mobile low-field intraoperative MRI system, a few epilepsy surgeries have been performed using this technique. As the integration of imaging and functional data plays an important role in the planning of epilepsy surgery, intraoperative verification of the surgical result may be highly valuable. Therefore, teams that have access to intraoperative MRI should be encouraged to use this technique prospectively to evaluate its current relevance in epilepsy surgery.

Juvenile hormone III and nutrition effects on spermatogenesis in the 4th instar nymphs of Panstrongylus megistus (Hemiptera: Reduviidae)

When 4th instar nymphs of Panstrongylus megistus are fed with a saturant blood meal, there is an intense proliferation of the spermatogonia. At the end of the intermoult, the older spermatogonial cysts differentiate into 1st primary spermatocyte cysts. In the nymphs deprived of the blood meal this evolution is not observed, but a small growth of the testicular follicles occurs, due to a few mitotic divisions. This growth is observed at least, until 25 days after ecdysis. Since day 15, an autolytic process starts in the older spermatogonial cysts. The presence of exogenous juvenile hormone III (JH III) does not promote the development of the germ cells in the fasting insects. There is only a small growth of the testicular follicles and the autolytic process is also observed. In the precocious adults obtained by allatectomy or precocene II treatment, germ cells are observed in all development stages, except packed and elongated spermatozoa bundels.

Varicocèle de l'enfant et de l'adolescent [Children and adolescent varicocele]

About 15% of adolescent males present with a varicocele. It rarely causes symptoms and is often diagnosed on the routine physical examination. There are evidences of an association between duration of a varicocele and testicular impairment. Surgical treatment is indicated in case of testicular growth arrest, testicular asymmetry, grade II or more, symptoms i.e. pain or swelling, parental or patient's anxiety. Several treatment options include open surgery (with or without micro-anastomosis), laparoscopy, embolization by interventional radiology, antegrade scrotal sclerotherapy. Informations should include a recurrence rate as hight as 15% whatever the technique may be, postoperative hydroceles and some testicular atrophies. Those complications can be delayed.

Exponentially small splitting of separatrices in the perturbed McMillan map

The McMillan map is a one-parameter family of integrable symplectic maps of the plane, for which the origin is a hyperbolic fixed point with a homoclinic loop, with small Lyapunov exponent when the parameter is small. We consider a perturbation of the McMillan map for which we show that the loop breaks in two invariant curves which are exponentially close one to the other and which intersect transversely along two primary homoclinic orbits. We compute the asymptotic expansion of several quantities related to the splitting, namely the Lazutkin invariant and the area of the lobe between two consecutive primary homoclinic points. Complex matching techniques are in the core of this work. The coefficients involved in the expansion have a resurgent origin, as shown in [MSS08].

Gundlachia dutrae: n. sp. from northwest Brazil (Mollusca: Basommatophora: Ancylidae)

A new species of Gundlachia, Gundlachia dutrae is described from northwest Brazil. It is distinguishable from other congenerie species by characteristics of the shell, radula and internal organs. Shell relatively high. Aperture near-circular; periostracum dark brown without periostracal hairs. Apex slightly inclined to the right, projected but not hooked, with an apical depression surrounted by a sculpture of well-marked irregular punctations. Shell surface with prominent radial sculpture. No septate specimens were observed. Ratios (n= 59): shell width/shell lenght = 0,66- 0,79 (mean 0,73); shell height/shell length = 0,32- 0,45 ( mean 0,37); shell height/shell width = 0,43- 0,63 (mean 0,51). Body of normal ancylid type; mantle pigmentation dark brown or black, concentrated along the mantle collar. The dorsal surface of the right anterior muscle is elongated and medially constricted. The left anterior and the posterior muscles are almost elliptical. Adhesive area is V-shaped. Pseudobranch unpigmented bearing a very small and thin dorsal lobe. Ovotestis with more than 25 unbranched diverticula. Ovispermiduct with seminal vesicle rather developed. Elongated nidamental gland continous with the glandular wall of the uterus. Nidamental gland appendix ending into a bulbous swelling Spermathecal body almost rounded. Well-developed prostate with five long diverticula. Ejaculatory complex with long glandular flagellum, without a penis or true ultra-penis. "Penis sheath" developed. "Ultra-penis" projected as a tube inside the lumem of prepuce, with a slit between "ultra-penis" and "penis sheath". Rachidian tooth tetracuspid, with two median cusps assymmetrical and aculeated. Lateral teeth tricuspid, with a reduced endocon and a prominent mesocon. A well marked gap occurs between meso and ectocon. Marginal teeth similar to lateral ones. Jaw T-shaped, with about 28 dorsal plates.

Novel testis germ cell-specific transcript of the CREB gene contains an alternatively spliced exon with multiple in-frame stop codons.

The gene encoding the cAMP-responsive transcription factor CREB consists of multiple small exons some of which undergo alternative RNA splicing. We describe the finding of a novel transcript of the CREB gene expressed at high levels in the germ cells of the rat testis. The transcript contains an alternatively spliced exon inserted within the sequence encoding the transcriptional transactivation domain of CREB and this exon contains multiple in-frame stop codons. Furthermore, the exon is conserved in both rat and human genes (75% nucleotide identity). Although the function(s) of this RNA or the truncated CREB protein predicted to result from the translation of this unusual transcript is unknown, the high level of expression in the testicular germ cells and remarkable conservation of sequences in rat and human suggests that it may have a unique biological function in these cells.

Revalidação do gênero Mepraia, Mazza, Gajardo & Jorg, 1940 (Hemiptera, Reduviidae, Triatominae)

The authors revalidate the genus Mepraia, described in 1940 by Mazza, Gajardo & Jörg. The genus is monotypic and represented by the species M. spinolai (Porter, 1934). Based on the characteres described below the authors considered the separation of the genus Triatoma Laporte, 1832 and the return of the genus Mepraia. Strongly alar polymorphism, the abdomen of female with connexivum like in genus Dipetalogaster Usinger 1939, seven testicular follicles, like in Triatoma, however with a different relation of lenghts; external male genitalia showing a big and foliar process of the conjunctiva, vesica with an arch-shape, struts and endosoma process absent.

Imaging of cavitary necrosis in complicated childhood pneumonia.

The aim of this study was to illustrate the chest radiographs (CR) and CT imaging features and sequential findings of cavitary necrosis in complicated childhood pneumonia. Among 30 children admitted in the Pediatric Intensive Care Unit for persistent or progressive pneumonia, respiratory distress or sepsis despite adequate antibiotic therapy, a study group of 9 children (5 girls and 4 boys; mean age 4 years) who had the radiographic features and CT criteria for cavitary necrosis complicated pneumonia was identified. The pathogens identified were Streptococcus pneumoniae( n=4), Aspergillus( n=2), Legionella( n=1), and Staphylococcus aureus( n=1). Sequential CR and CT scans were retrospectively reviewed. Follow-up CR and CT were evaluated for persistent abnormalities. Chest radiographs showed consolidations in 8 of the 9 patients. On CT examination, cavitary necrosis was localized to 1 lobe in 2 patients and 7 patients showed multilobar or bilateral areas of cavitary necrosis. In 3 patients of 9, the cavitary necrosis was initially shown on CT and visualization by CR was delayed by a time span varying from 5 to 9 days. In all patients with cavities, a mean number of five cavities were seen on antero-posterior CR, contrasting with the multiple cavities seen on CT. Parapneumonic effusions were shown by CR in 3 patients and in 5 patients by CT. Bronchopleural fistulae were demonstrated by CT alone ( n=3). No purulent pericarditis was demonstrated. The CT scan displayed persistent residual pneumatoceles of the left lower lobe in 2 patients. Computed tomography is able to define a more specific pattern of abnormalities than conventional CR in children with necrotizing pneumonia and allows an earlier diagnosis of this rapidly progressing condition. Lung necrosis and cavitation may also be associated with Aspergillus or Legionella pneumonia in the pediatric population.

Reduced fronto-temporal and limbic connectivity in the 22q11.2 deletion syndrome: vulnerability markers for developing schizophrenia?

The 22q11.2 deletion syndrome (22q11DS) is a widely recognized genetic model allowing the study of neuroanatomical biomarkers that underlie the risk for developing schizophrenia. Recent advances in magnetic resonance image analyses enable the examination of structural connectivity integrity, scarcely used in the 22q11DS field. This framework potentially provides evidence for the disconnectivity hypothesis of schizophrenia in this high-risk population. In the present study, we quantify the whole brain white matter connections in 22q11DS using deterministic tractography. Diffusion Tensor Imaging was acquired in 30 affected patients and 30 age- and gender-matched healthy participants. The Human Connectome technique was applied to register white matter streamlines with cortical anatomy. The number of fibers (streamlines) was used as a measure of connectivity for comparison between groups at the global, lobar and regional level. All statistics were corrected for age and gender. Results showed a 10% reduction of the total number of fibers in patients compared to controls. After correcting for this global reduction, preserved connectivity was found within the right frontal and right parietal lobes. The relative increase in the number of fibers was located mainly in the right hemisphere. Conversely, an excessive reduction of connectivity was observed within and between limbic structures. Finally, a disproportionate reduction was shown at the level of fibers connecting the left fronto-temporal regions. We could therefore speculate that the observed disruption to fronto-temporal connectivity in individuals at risk of schizophrenia implies that fronto-temporal disconnectivity, frequently implicated in the pathogenesis of schizophrenia, could precede the onset of symptoms and, as such, constitutes a biomarker of the vulnerability to develop psychosis. On the contrary, connectivity alterations in the limbic lobe play a role in a wide range of psychiatric disorders and therefore seem to be less specific in defining schizophrenia.

Fatal myocardial infarction after lung resection in a patient with prophylactic preoperative coronary stenting.

In this report we present the case of a 77-yr-old man who underwent resection of the upper lobe of the left lung for a carcinoma, six weeks after percutaneous transluminal coronary angioplasty (PTCA) with stenting of the left anterior descending (LAD) and circumflex coronary arteries. Antiplatelet therapy with clopidogrel was interrupted two weeks before surgery to allow for epidural catheter placement and to minimize haemorrhage. The surgical procedure was uneventful. In the immediate postoperative period, however, the patient suffered severe myocardial ischaemia. Emergency coronary angiography showed complete thrombotic occlusion of the LAD stent. In spite of successful recanalization, reinfarction occurred and the patient died in cardiogenic shock. Prophylactic preoperative coronary stenting may put the patient at risk of stent thrombosis if surgery cannot be postponed for three months. In such cases, other strategies such as perioperative beta-blockade for preoperative cardiac management should be considered.

GABA receptor subunits in human auditory cortex in normal and stroke cases.

GABA receptors are ubiquitous in the cerebral cortex and play a major role in shaping responses of cortical neurons. GABAA and GABAB receptor subunit expression was visualized by immunohistochemistry in human auditory areas from both hemispheres in 9 normal subjects (aged 43-85 years; time between death and fixation 6-24 hours) and in 4 stroke patients (aged 59-87 years; time between death and fixation 7-24 hours) and analyzed qualitatively for GABAA and semiquantitatively for GABAB receptor subunits. In normal brains, the primary auditory area (TC) and the surrounding areas TB and TA displayed distinct GABAA receptor subunit labeling with differences among cortical layers and areas. In postacute and chronic stroke we found a layer-selective downregulation of the alpha-2 subunit in the anatomically intact cerebral cortex of the intact and of the lesioned hemisphere, whereas the alpha-1, alpha-3 and beta-2/3 subunits maintained normal levels of expression. The GABAB receptors had a distinct laminar pattern in auditory areas and minor differences among areas. Unlike in other pathologies, there is no modulation of the GABAB receptor expression in subacute or chronic stroke.

Growing up with bilateral hippocampal atrophy: from childhood to teenage.

The respective roles of the medial temporal lobe (MTL) structures in memory are controversial. Some authors put forward a modular account according to which episodic memory and recollection-based processes are crucially dependent on the hippocampal formation whereas semantic acquisition and familiarity-based processes rely on the adjacent parahippocampal gyri. Others defend a unitary view. We report the case of VJ, a boy with developmental amnesia of most likely perinatal onset diagnosed at the age of 8. Magnetic resonance imaging (MRI), including quantitative volumetric measurements of the hippocampal formation and of the entorhinal, perirhinal, and temporopolar cortices, showed severe, bilateral atrophy of the hippocampal formation, fornix and mammillary bodies; by contrast, the perirhinal cortex was within normal range and the entorhinal and temporopolar cortex remained within two standard deviations (SDs) from controls' mean. We examined the development of his semantic knowledge from childhood to teenage as well as his recognition and cued recall memory abilities. On tasks tapping semantic memory, VJ increased his raw scores across years at the same rate as children from large standardisation samples, except for one task; he achieved average performance, consistent with his socio-educational background. He performed within normal range on 74% of recognition tests and achieved average to above average scores on 42% of them despite very severe impairment on 82% of episodic recall tasks. Both faces and landscapes-scenes gave rise to above average scores when tested with coloured stimuli. Cued recall, although impaired, was largely superior to free recall. This case supports a modular account of the MTL with episodic, but not semantic memory depending on the hippocampal formation. Furthermore, the overall pattern of findings is consistent with evidence from both brain-damaged and neuroimaging studies indicating that recollection requires intact hippocampal formation and familiarity relies, at least partly, on the adjacent temporal lobe cortex.

Abrupt decrease in serum testosterone levels after an oral glucose load in men: implications for screening for hypogonadism.

OBJECTIVE: This study examines the physiological impact of a glucose load on serum testosterone (T) levels in men with varying glucose tolerance (GT). DESIGN: Cross-sectional study. PATIENTS AND METHODS: 74 men (19-74 years, mean 51·4 ± 1·4 years) underwent a standard 75-g oral glucose tolerance test with blood sampling at 0, 30, 60, 90 and 120 min. Fasting serum glucose, insulin, total T (and calculated free T), LH, SHBG, leptin and cortisol were measured. RESULTS: 57% of the men had normal GT, 30% had impaired GT and 13% had newly diagnosed type 2 diabetes. Glucose ingestion was associated with a 25% decrease in mean T levels (delta = -4·2 ± 0·3 nm, P < 0·0001). T levels remained suppressed at 120 min compared with baseline (13·7 ± 0·6 vs 16·5 ± 0·7 nm, P < 0·0001) and did not differ across GT or BMI. Of the 66 men with normal T levels at baseline, 10 (15%) had levels that decreased to the hypogonadal range (<9·7 nm) at one or more time points. SHBG, LH and cortisol levels were unchanged. Leptin levels decreased from baseline at all time points (P < 0·0001). CONCLUSIONS: Glucose ingestion induces a significant reduction in total and free T levels in men, which is similar across the spectrum of glucose tolerance. This decrease in T appears to be because of a direct testicular defect, but the absence of compensatory changes in LH suggests an additional central component. Men found to have low nonfasting T levels should be re-evaluated in the fasting state.

Pédiatrie: nouveautés en médecine 2007 [Pediatrics]

Cette année, nous avons résumé les avances dans deux pathologies très fréquentes et deux plus rares : 1) la cryptorchidie est opérée plus précocement sans utiliser des hormones. Ce traitement vise à assurer la fertilité et à éviter le développement de tumeurs testiculaires. 2) Dans le traitement de la pharyngite streptococcique, les céphalosporines orales durant quatre à cinq jours, peuvent remplacer la pénicilline. 3) Le carvédilol (bêtabloquant), le lévosimendan (sensibilisateur du calcium) et le nésiritide (analogue du peptide natriurétique) permettent une approche neurohormonale à l'insuffisance cardiaque. 4) Les glucocorticoïdes administrés tôt et une prise en charge multidisciplinaire ralentissent le cours de la dystrophie musculaire de Duchenne. This article summarizes the medical progress achieved in 2 frequent and 2 rare pathologies: 1. Cryptorchidism should be operated around 12 months of age and hormonal treatment abandoned in order to maintain fertility and avoid development of testicular tumors. 2. For the treatment of streptococcal pharyngitis oral cephalosporins for 4 to 5 days are equivalent to a Penicillin treatment of 10 days. 3. Thanks to carvedilol (a beta-blocker agent), levosimendan (a calcium sensibiliser) and nesiritide (an analog to the natriuretic peptide) a new hormonal approach to cardiac failure is possible. 4. Corticosteroids allow to improve quality of live and life expectancy in Duchenne muscular dystrophy, provided treatment starts early and a multidisciplinary approach is assured