Patterns of single-neuron activity during associative recognition memory in the human medial temporal lobe.

Electrophysiological activity in medial temporal lobe (MTL) structures is pivotal for declarative long-term memory. Single-neuron and microcircuit findings capitalizing on human microwire recordings from the medial temporal lobe are still fragmentary. In particular, it is an open question whether identical or different groups of neurons participate in different memory functions. Here, we investigated category-specific responses in the human MTL based on single-neuron recordings in presurgical epilepsy patients performing an associative long-term memory task. Additionally, auditory beat stimuli were presented during encoding and retrieval to modulate memory performance. We describe the proportion of neurons in amygdala, entorhinal cortex, hippocampus and parahippocampal cortex belonging to different response classes. These entail neurons coding stimulus-familiarity, neurons coding successful item memory, and neurons coding associated source memory, as well as the overlap between these classes. As major results we demonstrate that neurons responding to stimulus familiarity (old/new effect) can be identified in the MTL even when using previously known rather than entirely novel stimulus material (words). We observed a significant overlap between familiarity-related neurons and neurons coding item retrieval (remembered/forgotten effect). The largest fraction of familiarity-related neurons was found in the parahippocampal cortex, and a considerable fraction of all parahippocampal neurons was related to successful item retrieval. Neurons related to successful source retrieval were different from the neurons coding the associated information. Most importantly, there was no overlap between neurons coding item memory and those coding associated source memory strongly suggesting that these functions are facilitated by different sets of neurons.

Brain-derived neurotrophic factor: its impact upon neuroplasticity and neuroplasticity inducing transcranial brain stimulation protocols.

Val66Met (rs6265) is a gene variation, a single nucleotide polymorphism (SNP) in the brain-derived neurotrophic factor (BDNF) gene that codes for the protein BDNF. The substitution of Met for Val occurs at position 66 in the pro-region of the BDNF gene and is responsible for altered activity-dependent release and recruitment of BDNF in neurons. This is believed to manifest itself in an altered ability in neuroplasticity induction and an increased predisposition toward a number of neurological disorders. Many studies using neuroplasticity-inducing protocols have investigated the impact of the BDNF polymorphism on cortical modulation and plasticity; however, the results are partly contradictory and dependent on the paradigm used in a given study. The aim of this review is to summarize recent knowledge on the relationship of this BDNF SNP and neuroplasticity.

European genetic variants associated with type 2 diabetes in North African Arabs.

AIMS: Recent genome-wide association studies (GWAS) and previous approaches have identified many genetic variants associated with type 2 diabetes (T2D) in populations of European descent, but their contribution in Arab populations from North Africa is unknown. Our study aimed to validate these markers and to assess their combined effects, using large case-control studies of Moroccan and Tunisian individuals. METHODS: Overall, 44 polymorphisms, located at 37 validated European loci, were first analyzed in 1055 normoglycaemic controls and 1193 T2D cases from Morocco. Associations and trends were then assessed in 942 normoglycaemic controls and 1446 T2D cases from Tunisia. Finally, their ability to discriminate cases from controls was evaluated. RESULTS: Carrying a genetic variant in BCL11A, ADAMTS9, IGF2BP2, WFS1, CDKAL1, TP53INP1, CDKN2A/B, TCF7L2, KCNQ1, HNF1A, FTO, MC4R and GCK increased the risk of T2D when assessing the Moroccan and Tunisian samples together. Each additional risk allele increased the susceptibility for developing the disease by 12% (P = 9.0 × 10(-9)). Genotype information for 13 polymorphisms slightly improved the classification of North Africans with and without T2D, as assessed by clinical parameters, with an increase in the area under the receiver operating characteristic curve from 0.64 to 0.67 (P = 0.004). CONCLUSION: In addition to TCF7L2, 12 additional loci were found to be shared between Europeans and North African Arabs. As for Europeans, the reliability of genetic testing based on these markers to determine the risk for T2D is low. More genome-wide studies, including next-generation sequencing, in North African populations are needed to identify the genetic variants responsible for ethnic disparities in T2D susceptibility.

[Place of pelvic ultrasonography using transabdominal technique in the investigation of premature ovarian failure]. / Place de l'échographie pelvienne réalisée par voie sus-pubienne dans l'exploration de l'insuffisance ovarienne prématurée.

OBJECTIVES: The aim of the present study was to characterize women with premature ovarian failure (POF) by their ovarian ultrasonographic appearances using transabdominal technique to establish the relationship to clinical, hormonal status, and genetic analysis. PATIENTS AND METHODS: We studied a cohort of 80 patients suffering from POF. The surface of the ovary was calculated and we identified the detection or not of follicles. RESULTS: The detection of the two ovaries by ultrasound was positive in 33 patients; only one ovary was identified in seven patients; none was noted in 40 patients. The surface of the ovaries ranged between 0.74 et 5.92 cm(2) (2.2+/-1.13 cm(2)). Ultrasonography identified follicles in 23 patients (28.75%). The presence of follicles suggested at ultrasonography was detected in 14 cases (70%) in normal-sized ovaries (> or =2 cm(2)) and in nine cases (45%) in small-sized ovaries (p=0.1). No significative statistical difference was found between the ultrasonographic appearances and the type of amenorrhea, pubertal development, hormonal status (estradiol, testosterone and delta-4-androstendione) and the chromosomal analysis. CONCLUSION: The clinical and hormonal status and the genetic analysis can't predict the presence or not of follicles in the ovaries of patients with POF.

Corticomedullary mixed tumor of the adrenal gland.

A 34-year-old woman presented with weight gain, hirsutism, recent hypertension and secondary amenorrhea. Laboratory findings showed hypokalemia, elevated cortisol and androgen levels with normal urine metanephrines and normal aldosteronemia. Abdominal magnetic resonance imaging showed a right heterogeneous adrenal mass measuring 4 x 6 cm with mixed component of fat and adrenal tissue suggesting corticosurrenaloma. After right adrenalectomy, blood pressure normalized and hypokalemia resolved. In the postoperative course, the patient presented adrenal insufficiency treated with hydrocortisone hemisuccinate. Histological examination showed a single tumor mass composed of an admixed population of adrenal cortical and medullary cells. Immunohistochemical evaluation was positive for chromogranin A.

Prevalence of antineutrophil cytoplasmic antibodies during treatment with benzylthiouracil.

BACKGROUND: Drug induced antineutrophil cytoplasmic antibodies (ANCA) associated vasculitis is a rare complication associated especially with propylthiouracil (PTU). Prevalence of ANCA in patients receiving PTU is well established. Few cases of vasculitis were also reported with benzylthiouracil (BTU). The objective of this study is to clarify the prevalence of ANCA in patients receiving BTU. METHODS: ANCA were investigated by indirect immunofluoresence and enzyme linked immunosorbant assay in 159 patients with Graves' disease (86 untreated and 73 treated with BTU). RESULTS: ANCA were positive in three (3.5%) untreated patients and 27 (37%) treated ones. Titres of ANCA varied between 1:20 and 1:200. There was a significant association between BTU treatment and ANCA (p<0.001). ANCA were directed against myeloperoxidase (MPO) in 28 (93.3%) patients. Median treatment duration was 24 months (ranges 0.5 to 144 months). There was no significant association between treatment duration and ANCA. Vasculitis was found in two (2.7%) treated patients. One patient has developed isolated cutaneous vasculitis and the other one a pulmonary vasculitis with diffuse alveolar haemorrhage. CONCLUSION: BTU therapy is characterised by a high prevalence of ANCA mainly but not exclusively directed against MPO. However, vasculitis remains a rare complication.

Diabetes mellitus as an early symptom of pancreatic cancer diagnosed three years later.

We present a case of a 40-year-old man with strong family history of diabetes. His pancreatic ultrasonography was normal at the discovery of his diabetes. Anti-pancreatic antibodies were negative. The patient was treated by insulin and continued to loose weight. His diabetes remained unstable during the follow-up. Three years later, a pancreatic adenocarcinoma was diagnosed which was locally advanced and could not be removed surgically. This observation argues among several mechanisms explaining diabetes in subjects with pancreatic cancer, in favor of tumor-derived diabetogenic substance and suggests that diabetes mellitus could reveal pancreatic cancer even in the presence of conventional risk factors of type 2 diabetes.

Archimedean copula model selection under dependent truncation.

One-sided truncated survival data arise when a pair of time-to-event variables (X, Y) is observed only when X

Retroperitonial liposarcoma mimicking pheochromocytoma.

The authors report the case of a 46-year-old woman who presented with a 4 month history of paroxystic and recent hypertension accompagned by headaches, tachycardia and sweating. The patient had decreased appetite with epigastric discomfort and abdominal distension. Physical examination was initially normal with mainly normal tension and no abdominal or lombar mass in palpation. While hospitalised, she developed paroxystic crisis of flush, headaches and hypertension of 190/100 mmHg. Biological findings revealed hypokaliemia and normal kaliuria on 3 day samples, with normal glycaemia and normal creatininaemia. Hormonal investigation revealed elevated metanephrines (3 mg/24 hours). Magnetic resonance imaging showed an 11 cm x 8.5 cm retroperitoneal mass with an enhanced signal in T2, a hypotrophic non-functional left kidney and no adrenal adenoma. Clinical and hormonal features suggested a diagnosis of pheochromocytoma. After preoperative medication, open excision, including left radical nephrectomy and adrenalectomy, normalized the catecholamine urinary level, resolved hypokalemia, and improved hypertension. Pathologic examination revealed a well-differentiated liposarcoma, without any pheochromocytoma component, and left adrenal hyperplasia. The tumour cells were immunonegative for chromogranin A. No metastatic lesion was identified by thoraco-abdominal computed tomography.

[MRI and pituitary adenoma]. / IRM et adénomes hypophysaires.

Pituitary is the most important gland of the organism which can be affected by many diseases, especially by adenomatous processes. Classically macroadenoma, microadenoma and picoadenoma are described, according to the size of the pituitary adenoma. The diagnosis of microadenoma was long considered a highly difficult task and that of picoadenoma was impossible by computed tomography. Recently, the high resolution of multiplanar MRI has enabled the diagnosis of microadenomas measuring less than 3 mm (picoadenoma). For macroadenoma, MRI not only contributes to diagnosis but is particularly important to assess the extension and to detect possible complications. The aim of our study is to illustrate MRI features in pituitary adenoma.

[Factitious Cushing syndrome: two case reports]. / Le syndrome de Cushing factice: deux observations.

INTRODUCTION: Search of corticosteroid use is an important precaution before any exploration of hypercorticism. Nevertheless, this use may be factitious leading to serious misdiagnosis and pitfalls. EXEGESIS: We report two cases of 29 and 60 years old male patients, referred for hypercorticism with patent features including metabolic and trophical signs. Laboratories findings revealed unelevated urinary cortisol values (40 and 27 microg/ day) in both cases with normal ACTH and normal plasmatic cortisol response to synacthène (32,5 and 35 microg/dl). Corticosteroid use, initially denied, was finally approved by the patients (hydrocortisone and dexamethasone for the first patient and betametasone for the second). So, they were assigned to psychiatric therapy. CONCLUSION: Our cases emphasize that corticosteroid misuse must be evoked in patients with unexpected hormonal assessment of pituitary adrenal axis despite patent clinical features of hypercorticism. Several specific tests are actually available for detect factitious Cushing syndrome. However, differential diagnostic remains difficult mainly with pseudo Cushing and cyclical Cushing syndromes.

[Nontraumatic ethmoid cerebrospinal fluid rhinorrhea complicating Sheehan syndrome]. / Rhinorrhée par fistule ethmoïdale spontanée compliquant un syndrome de Sheehan.

INTRODUCTION: Treatment of pituitary macroadenoma frequently leads to nontraumatic cerebrospinal fistula and rhinorrhea. We report an unusual case of rhinorrhea in a woman with Sheehan's syndrome. CASE: A 39-year-old woman receiving hormone replacement therapy for hypothyroidism diagnosed 13 years earlier (Sheehan's syndrome) developed metabolic syndrome, which combining obesity, type 2 diabetes, hypertension and mixed hyperlipidemia. Cerebrospinal fluid rhinorrhea was confirmed by measurement of the glucose concentration in her nasal discharge and by cerebral MRI, which revealed a fistula of the ethmoid bone and an empty sella. Etiological screening was negative, and normal bone densitometry as well as the absence of trauma ruled out any bone defects. Conversely, the metabolic syndrome, notably obesity, suggested a nontraumatic mechanism for the empty sella. DISCUSSION: Onset of empty sella syndrome during treatment for Sheehan's syndrome may be the cause of the CSF rhinorrhea. The role of obesity requires further investigation.

[Langerhans cell histiocytosis associated with pituitary stalk transection]. / Histiocytose langerhansienne multiviscérale associée à un syndrome d'interruption de la tige pituitaire.

UNLABELLED: Clinical manifestations of hypothalamic-pituitary Langerhans'cell histiocytosis are commonly, diabetes insipidus and sometimes growth hormone deficiency. Their morphologic characteristics on magnetic resonance imaging are absence of posterior pituitary hyperintensity and thickening of the pituitary stalk. Pituitary stalk transection is characterized on magnetic resonance imaging by the absence of pituitary stalk visibility, hypoplasia of the anterior hypophysis and ectopic posterior pituitary hyperintense signal. This syndrome has been shown to be associated with either isolated growth hormone deficiency or multiple anterior pituitary hormone deficiency, but normal posterior pituitary function. CASE REPORT: We report our experience with a six-year-old boy who had been treated for three years for a multisystem Langerhans'cell histiocytosis with diabetes insipidus and who was admitted because of short stature. Endocrinological examinations demonstrated a profound growth hormone deficiency and a partial central hypocorticism. Magnetic resonance imaging showed pituitary stalk transection and a midline anomaly of the brain (Arnold Chiari type I malformation). CONCLUSION: Although, some events of his perinatal history lead to the hypothesis of a malformative origin, the progression of Langerhans' cell histiocytosis affected tissues to fibrosis, suggest that this disease is the cause of the patient's hypothalamohypophyseal lesions.

[Mucormycosis in the diabetic patient]. / La mucormycose chez le diabétique.

INTRODUCTION: Mucormycosis is a rare, devastating, fungal infection, which disproportionately affects non-controlled diabetic patients, notably during ketoacidosis. It can be manifested in rhinocerebral, but also pulmonary and disseminated forms. OBSERVATIONS: Four consecutive diabetic patients who were admitted to the Farhat Hached Hospital, Sousse, Tunisia, between January 2001 and November 2002, are presented. Three patients exhibited ketoacidosis and one renal failure with hyperosmolarity. Infection was limited to the sinuses in two cases, to lower respiratory tract in one case, and was probably disseminated in one case. Diagnosis was confirmed by mycological and histological findings in all cases. Systemic Amphotericin B was associated with surgical debridement of the lesions in patients with rhinocerebral involvement. DISCUSSION: Despite aggressive therapy, mortality was high (3 out of 4 patients). Mucormycosis remains a severe, frequently fatal disease in diabetic patients.

[Hepatic abscess in diabetics, 2 case reports]. / Abcès hépatique chez le diabétique. 2 observations.

INTRODUCTION: Over the past few years, the hepatic abscess appears as a privileged septic localisation in the case of diabetes mellitus, particularly in the elderly. OBSERVATIONS: Two, 75 year-old and 82 year-old, diabetic patients were hospitalised for non-ketonic decompensation of type 2 diabetes mellitus. Examination revealed a sub-febrile state, the absence of clinical hepatic signs and a biological infectious syndrome The abscesses were discovered during the systematic hepatic sonography. Liver puncture was only possible in one patient and revealed Klebsiella oxytoca. The progression with antibiotics alone in one patient, and associated with surgical draining in the other, was positive. The origin appeared to be bilary in one patient and arterial on the other. COMMENTS: These case reports underline the interest of the systematic evocation of an abscessed hepatic localisation in cases of imbalance in diabetes, particularly when associated with an unexplained infectious syndrome.

[Craniopharyngioma of the adults. Three cases]. / Le craniopharyngiome de l'adulte. A props de trois cas.

Craniopharyngioma, an intra- and suprasellar tumor generally observed in pediatric patients, can also occur in adults. We report three cases of histologically confirmed craniopharyngioma in three men aged 34 to 53 Years. Clinical manifestations were headache with visual and gonadic disorders associating impotence, infertiligy, and gynecomastia. Computed tomographic and magnetic resonance imaging revealed an intra- and suprasellar tumor with solid, hydric, and calcified components. Third ventricle compression was observed in two patients. Hormone test revealed gonadotrope insufficiency in two patients, associated with hyperprolactinemia in one of them, and pituitary insufficiency in the third patient. None of the patients had diabetes insipidus. The frontopterional approach was used for surgery. One patient died and the two others experienced persistent visual impairment with worsening pituitary insufficiency. Our observations suggest that these craniopharyngiomas were probably clinically latent congienital forms since endocrine features were lacking during childhood. Early diagnosis is required to achieve good outcome.

[Post-partum autoimmune thyroiditis in a patient presenting with Sheehan's syndrome]. / Thyroïdite auto-immune du post-partum chez une patiente présentant un syndrome de Sheehan.

A 30-year-old women developed post-partum thyroiditis associated with post- partum pituitary infarction. Pituitary stimulation tests demonstrated global pituitary deficiency but there was no thyrotropin response to TRH stimulation and free T4 was normal. Associated goiter and high circulating levels of microsomal antibodies led to the diagnosis of post-partum thyroiditis associated with pituitary deficiency. Two cases of this unusual association have been reported. The underlying pathogenesis might involve post-partum immunological rebound and/or hypocorticism-induced immunological disorders.