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.

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.

[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.

[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.

[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.

Juvenile idiopathic chronic calcifying pancreatitis: report of 10 cases from central Tunisia.

A series of 10 cases of chronic calcifying pancreatitis from central Tunisia are reported. The mean age at presentation was 23 years and the male to female ratio was 1.5. The main clinical manifestations of the disease were abdominal pain (eight cases), weight loss (four cases), and diarrhea (three cases). Diabetes was recorded in four cases. The etiological investigations yielded negative results in all the patients. It is concluded that central Tunisia should be added to the regions where juvenile chronic calcifying pancreatitis of the "tropical type" may be observed.

Primary amenorrhea-galactorrhea with hyperprolactinemia and huge pituitary enlargement in juvenile primary hypothyroidism.

We report a girl with juvenile primary hypothyroidism revealed by growth retardation and a syndrome of primary amenorrhea-galactorrhea with hyperprolactinemia and suprasellar pituitary enlargement. Resolution of the pituitary enlargement and the amenorrhea-galactorrhea syndrome occurred after thyroid hormone replacement. No similar observation has been reported earlier in juvenile hypothyroidism.

[Emphysematous pyelonephritis. Apropos of a case diagnosed by ultrasonography]. / Pyélonéphrite emphysémateuse. A propos d'un cas diagnostiqué par échographie.

Emphysematous pyelonephritis is a severe infection of the Kidney observed mainly in diabetic patients. The disease is characterized by the production of intra-renal and occasionally perirenal gas. Because of the high mortality associated with this fulminant septic infection, it is imperative to establish a prompt diagnosis and start an appropriate therapy early in the course of the disease. We report a case of emphysematous pyelonephritis diagnosed by sonography: sonographic features consist of multiple high amplitude echoes within the renal parenchyma, renal sinus and perirenal space associated with distal shadows containing low level echoes. We discuss the value of the radiologic imaging methods.

[Antithyroid antibodies. Prevalence in primary hypothyroidism in Central Tunisia]. / Les anticorps antithyroïdiens. Prévalence dans l'hypothyroïdie primaire en Tunisie Centrale.

Thyroid microsomal (AAM) and thyroglobulin antibodies (AAT) were studied in sera of 112 patients with overt primary hypothyroidism in Central Tunisia. Thyroid antibodies were detected by an agglutination method. AAM and AAT were found respectively in 78.6% and 42%. The data confirm that there is a high prevalence of antibodies in primary hypothyroidism of short duration (AAM: 90%, AAT: 56.7%). The study reflect the prevalence of Hashimoto's thyroiditis and point to the usefulness of thyroid auto-antibodies in early screening of symptomless autoimmune thyroiditis.

[Spironolactone in idiopathic hirsutism, clinical and biological evaluation of treatment]. / La spironolactone dans l'hirsutisme idiopathique, évaluations clinique et biologique du traitement.

Ten midly hirsute women with normal serum levels of testosterone were treated with spironolactone (100 mg die), and the effectiveness of this dose-schedule regimen was evaluated after six months of therapy. Hirsutism subsided partly in all women. We estimated however, that in 6 of the 10 women, the clinical benefit was out weighed by the side effects and other drawbacks of a long term therapy and their medication was then stopped 6 months after its initiation. The changes induced on the pituitary function were evaluated by measuring basal serum T3 T4 and basal and stimulated (TRH-LHRH) TSH, PRL, FSH and LH, prior to and after one month of therapy. Spironolactone induced a greater response of TSH to TRH (p less than .025) but no change in T3 T4, PRL, FSH and LH. These data suggest that changes in TSH response are not explained by the speculated intrinsic oestrogenic activity of spironolactone but rather by a selective interaction with TSH secreting cells. We conclude that spironolactone therapy should not be recommended for the large category of normal women complaining of slight increase of facial hair.

[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.

[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.

[Sheehan's syndrome followed by spontaneous pregnancy. Apropos of 2 cases]. / Syndrome de Sheehan suivi d'une grossesse spontanée. A propos de deux observations.

There are few reports of spontaneous pregnancies in patients with Sheehan's syndrome. We describe two cases which exhibited adrenal and thyroid insufficiency but not amenorrhea, return of the menstrual periods being at the expected time after delivery. Endocrinologic studies confirmed thyrotropin and corticotropin insufficiency. Clinical evidence of preserved gonadotropin secretion was supported by the response of LH and FSH to acute administration of synthetic LHRH and by the fact that thyroid and corticoid hormonal replacement resulted in a spontaneous pregnancy with successful outcome.

[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.

[Rapid beta 1-24-corticotropin test in the exploration of the corticotropic axis. 71 cases]. / Le test rapide à la beta 1-24 corticotrophine dans l'exploration de l'axe corticotrope. Soxiante et onze observations.

The reliability of the beta 1-24 corticotropin test, which is both cheap and safe, in the assessment of the hypothalamic-pituitary-adrenocortical function was re-evaluated by comparing its results with those of the metyrapone test in 71 subjects: 30 controls and 51 patients with suspected pituitary-adrenal dysfunction. Response to a 500 micrograms intramuscular injection of beta 1-24 corticotropin was evaluated by measuring the 60 min plasma cortisol levels; 4.5 g of metyrapone divided into 6 doses were then administered orally and response was evaluated by measuring plasma 11-desoxycortisol levels. A highly significant correlation (r = 0.79; p less than 0.001) was observed between plasma cortisol and plasma 11-desoxycortisol levels. The results were best interpreted by expressing the values obtained as plasma cortisol concentrations which, in normal subjects are at least 21 micrograms/100 ml. The rapid beta 1-24 corticotropin test was found to be very reliable (sensitivity 90%, specificity 100%) to detect adrenal insufficiency, irrespective of the organs affected on the hypothalamic-adrenocortical axis.

[Thyroid pseudo-nodules: 3 case reports]. / Les pseudo-nodules thyroïdiens: à propos de 3 cas.

The thyroïd pseudo-nodules constitute cervical lesions that can simulating neoplastic thyroid lesions either by their size or by their "cold" character in scintigraphy. We describe 3 cases of thyroïd pseudo-nodules collected in 10 years: a thyroid hydatid cyst, a schwannoma of the recurrent nerve and a thyroglossal duct cyst. Throw these observations, the authors discuss the problems of differential diagnosis set out with these pseudo-nodules. Although the diagnosis in the 3 cases, was histological after post operative exam, the authors insist throw a review of the literature, on the place of fine needle aspiration cytology in the therapeutic strategy that can show specific signs for some lesions. For the other cases, surgery resection is effected to eliminate malignant lesions who are the principal differential diagnosis of thyroid pseudo-nodules.