Hippocampal LTP modulation and glutamatergic receptors following vestibular loss.

Vestibular dysfunction strongly impairs hippocampus-dependent spatial memory performance and place cell function. However, the hippocampal encoding of vestibular information at the synaptic level, remains sparsely explored and controversial. We investigated changes in in vivo long-term potentiation (LTP) and NMDA glutamate receptor (NMDAr) density and distribution after bilateral vestibular lesions (BVL) in adult rats. At day 30 (D30) post-BVL, the LTP of the population spike recorded in the dentate gyrus (DG) was higher in BVL rats, for the entire 3 h of LTP recording, while no difference was observed in the fEPSP slope. However, there was an increase in EPSP-spike (E-S) potentiation in lesioned rats. NMDArs were upregulated at D7 and D30 predominantly within the DG and CA1. At D30, we observed a higher NMDAr density in the left hippocampus. NMDArs were overexpressed on both neurons and non-neuronal cells, suggesting a decrease of the entorhinal glutamatergic inputs to the hippocampus following BVL. The EPSP-spike (E-S) potentiation increase was consistent with the dorsal hippocampus NMDAr upregulation. Such an increase could reflect a non-specific enhancement of synaptic efficacy, leading to a disruption of memory encoding, and therefore might underlie the memory deficits previously reported in rats and humans following vestibular loss.

Flow cytometry for receptor analysis from ex-vivo brain tissue in adult rat.

BACKGROUND: Flow cytometry allows single-cell analysis of peripheral biological samples and is useful in many fields of research and clinical applications, mainly in hematology, immunology, and oncology. In the neurosciences, the flow cytometry separation method was first applied to stem cell extraction from healthy or cerebral tumour tissue and was more recently tested in order to phenotype brain cells, hippocampal neurogenesis, and to detect prion proteins. However, it remains sparsely applied in quantifying membrane receptors in relation to synaptic plasticity. NEW METHOD: We aimed to optimize a flow cytometric procedure for receptor quantification in neurons and non-neurons. A neural dissociation process, myelin separation, fixation, and membrane permeability procedures were optimized to maximize cell survival and analysis in hippocampal tissue obtained from adult rodents. We then aimed to quantify membrane muscarinic acetylcholine receptors (mAChRs) in rats with and without bilateral vestibular loss (BVL). RESULTS: mAChR's were quantified for neuronal and non-neuronal cells in the hippocampus and striatum following BVL. At day 30 but not at day 7 following BVL, there was a significant increase (P ≤ 0.05) in the percentage of neurons expressing M2/4 mAChRs in both the hippocampus and the striatum. CONCLUSION: Here, we showed that flow cytometry appears to be a reliable method of membrane receptor quantification in ex-vivo brain tissue.

Application of HBOCs electrophoretic method to detect a new blood substitute derived from the giant extracellular haemoglobin of lugworm.

Manipulation of blood and blood components is prohibited in sports by the World Anti-Doping Agency (WADA). This includes the use of blood substitutes to increase oxygen transport, like haemoglobin-based oxygen carriers (HBOCs), which are compounds derived from haemoglobin. Despite their medical interest, the first generation of HBOCs had serious adverse effects and was abandoned. However, new studies are now exploiting the properties of marine worm haemoglobins, which circulate as giant extracellular complexes with high oxygen-binding capacities. HEMOXYCarrier® (HC), developed by Hemarina, is one of the most advanced and promising HBOCs, and HC may become a tempting doping tool for athletes in the future. Here, HC detection in plasma/serum was evaluated with the method used to detect the first HBOCs, based on electrophoresis and heme peroxidase properties. An HC-derived product was identified in human plasma up to 72 h after in vitro incubation at 37 °C. HC degradation also induced methemalbumin formation. After injecting HC at the effective dose of 200 mg/kg into mice, the HC-derived product was detected only for a few hours and no accumulation of methemalbumin was observed. Due to this limited detection window in vivo, measuring specific worm globin degradation products by mass spectrometry might be an alternative for future anti-doping analyses. Copyright © 2016 John Wiley & Sons, Ltd.

Chemotherapy (platinum and pemetrexed) in combination with erlotinib in non-small cell lung cancer induces major gastrointestinal toxicity: two case reports from the FLARE/GFPC 03-2013 study.

WHAT IS KNOWN AND OBJECTIVE: A randomized phase III study was designed to assess the efficacy and safety of second-line platinum-based chemotherapy with or without erlotinib in non-small cell lung cancer (NSCLC) with EGFR-activating mutation after secondary resistance to EGFR-TKIs (epidermal growth factor receptor tyrosine kinase inhibitors). CASE SUMMARY: We report herein two of the first three patients who presented with major gastrointestinal toxicities in the experimental arm of the trial. WHAT IS NEW AND CONCLUSION: Pending further data, it would seem safer to administer EGFR-TKIs and chemotherapy sequentially rather than concomitantly.

Altered diurnal pattern of steroid hormones in relation to various behaviors, external factors and pathologies: A review.

The adrenal and gonadal stress steroids [i.e., cortisol, testosterone and dehydroepiandrosterone (DHEA)] have gathered considerable attention in the last few decades due to their very broad physiological and psychological actions. Their diurnal patterns have become a particular focus following new data implicating altered diurnal hormone patterns in various endocrine, behavioral and cardiovascular risk profiles. In this review of the current literature, we present a brief overview of the altered diurnal patterns of these hormones that may occur in relation to chronic stress, nutritional behaviors, physical exercise, drugs and sleep deprivation/shift. We also present data on the altered diurnal hormone patterns implicated in cardiometabolic and psychiatric/neurologic diseases, cancer and other complex pathologies. We consider the occasionally discrepant results of the studies, and summarize the current knowledge in this new field of interest, underlining the potential effects on both biological and psychological functioning, and assess the implications of these effects. Last, we conclude with some practical considerations and perspectives.

Influence of vestibular input on spatial and nonspatial memory and on hippocampal NMDA receptors.

It has recently been shown that a lack of vestibular sensory information decreases spatial memory performance and induces biochemical changes in the hippocampus in rodents. After vestibular neurectomy, patients display spatial memory deficit and hippocampal atrophy. Our objectives were to explore: (a) spatial (Y maze, radial-arm maze), and non-spatial (object recognition) memory performance, (b) modulation of NMDA receptors within the hippocampus using radioligand binding, and (c) hippocampal atrophy, using MRI, in a rat model of bilateral labyrinthectomy realized in two operations. Chemical vestibular lesions (VLs) were induced in 24 animals by transtympanic injections of sodium arsanilate (30 mg/0.1 ml/ear), one side being lesioned 3 weeks after the other. The control group received transtympanic saline solution (0.1 ml/ear) (n = 24). Spatial memory performance (Y maze and radial maze) decreased after VL. Conversely, non-spatial memory performance (object recognition) was not affected by VL. No hippocampal atrophy was observed with MRI, but density of NMDA receptors were increased in the hippocampus after VL. These findings show that the lack of vestibular information induced specific deficits in spatial memory. Additionally, quantitative autoradiographic data suggest the involvement of the glutamatergic system in spatial memory processes related to vestibular information. When studying spatial memory performances in the presence of vestibular syndrome, two-step labyrinthectomy is a suitable procedure for distinguishing between the roles of the specific components of vestibular input loss and those of impaired locomotor activity.

[Colchicine intoxication in four elderly patients: how to prevent it?]. / Risque d'intoxication à la colchicine chez les personnes âgées et moyens de prévention: à propos de quatre observations.

INTRODUCTION: In France, unlike other countries, the use of colchicine is preferred to other anti-inflammatory drugs for the treatment of gout. CASE REPORTS: We report a case series of four elderly patients (range from 72 to 83 years of age) who presented with colchicine intoxication, all notified to the Basse-Normandie pharmacovigilance centre in 2007. For each patient, one or more risk factors were identified: renal failure, high initial dosage, absence of laboratory monitoring. CONCLUSION: It would be useful to establish specific guidelines for colchicine use in the elderly population.

[Trimetazidine-induced encephalopathy with choreiform disorders: a case report]. / Encéphalopathie avec mouvements choréiformes induits par la trimétazidine: à propos d'un cas.

Trimetazidine is known to induce parkinsonism but choreiform disorders have not yet been described with this drug. A 88-year-old patient treated with trimetazidine developed choreiform movements, gait disorders, tremor and visual hallucinations. These symptoms disappeared after drug withdrawal. Although this drug contains a piperazinic ring like other anti-dopaminergic drugs which are already known to potentially induce chorea like neuroleptics and some anti-convulsive drugs. When a patient treated with trimetazidine develops or worsens motor disorders (parkinsonism or choreiform disorders), this drug must be stopped.

[Should we care about pregabalin for elderly patients with a history of cardiac dysrhythmia?]. / Faut-il se méfier de la prégabaline chez les patients âgés aux antécédents de troubles du rythme cardiaque ?

Pregabalin is similar in structure to gamma-aminobutyric acid. It is used for neuropathic pain, generalized anxiety disorders and as an adjunct therapy for partial seizures. Tachycardia is a rare side-effect. A 92-year-old patient with a history of paroxystic fibrillation was hospitalised for zoster. She developed a sinusal tachycardia followed by atrial fibrillation and congestive heart failure 15 h after a first dose of pregabalin. The imputation was considered as plausible. Even though the mechanism remains unclear, pregabalin might induce tachycardia in predisposed old patients.

Cyclosporine monitoring in peripheral blood mononuclear cells: feasibility and interest. A prospective study on 20 renal transplant recipients.

Cyclosporine (CsA) has potent immunosuppressive properties, reflecting its ability to block the transcription of cytokine genes (mainly interleukin 2) in CD4+ T lymphocytes, markedly improving transplantation outcomes in the past 20 years. CsA pharmacokinetic variability and renal toxicity require whole blood (WB) monitoring by 4-hour area under the drug concentration curves (AUC0-4) or 2-hour postdose concentration (C2) monitoring. Nevertheless, graft rejection can occur despite target blood levels, suggesting that WB monitoring does not guarantee optimal immunosuppression. For a decade, pharmacologists and clinicians have worked to optimize CsA doses; some authors, inspired by its mechanism of action, have proposed therapeutic drug monitoring using peripheral blood mononuclear cells (PBMC; lymphocytes and monocytes). The aim of this study was to assess the feasibility and interest of CsA monitoring in PBMC ([CsA]PBMC). We also measured in vitro distribution of CsA in CD4+ and CD4- subsets.

[Acute renal failure with acyclovir in a 42-year-old patient without previous renal dysfunction]. / Insuffisance rénale aiguë sous aciclovir chez un patient de 42 ans sans atteinte rénale préalable.

INTRODUCTION: Herpetic meningoencephalitis is treated with acyclovir (15 mg/kg/8 h). This higher dosage enhance the risk of acute renal failure. CASE REPORT: We report the case of a previously healthy 42 years old man treated by intravenous aciclovir 1g/8 h for a herpetic meningoencephalitis. He presented an acute renal failure and an acute confusional state at the end of the treatment. Renal function and neurologic status improved rapidly with increased hydration and stop of the antiviral therapy. CONCLUSION: If acyclovir is usually well tolerated, there is also a risk of acute nephropathy, especially dose-dependent. We point out the need to monitor renal function when high dosage of acyclovir is indicated.

Serum erythropoietin levels in septic shock.

Erythropoietin is a glycoprotein hormone mainly released by the kidney, which stimulates red blood cell production. However, in sepsis, the mechanisms responsible for the final increase in circulating erythropoietin remain unclear Seventeen critically ill patients with Simplified Acute Physiologic Score average 66 (range 43 to 103) were included in this study. Ten patients survived and seven died within 28 days. Blood samples obtained at different times were assayed for erythropoietin, cytokine levels and lactate measurements. PCO2 gap was assessed to detect the presence of gastric mucosal acidosis. Erythropoietin decreased in the patients who survived while it remained high or increased in non-survivors (37+/-6.5 vs 147+/-6. 7 UI/l respectively, P<0.05). Erythropoietin plasma levels were correlated with IL-6 levels (r=0.84, P<0.05) and TNFalpha levels (r=0.84, P<0.05). We observed a significant positive relationship between erythropoietin plasma levels and lactate concentrations (r= 0.89, P< 0. 05) and with PCO2 gap (r=0.9, P < 0.05). No correlation was found between erythropoietin concentration and the other parameters. High serum erythropoietin levels in non-survivors were observed with septic shock despite an increase in the levels of proinflammatory cytokines. We found a relationship between erythropoietin concentration and biological markers of tissue hypoperfusion i.e. lactate levels or PCO2 gap. This relationship could suggest tissue hypoperfusion as the stimulating factor for erythropoietin production in septic shock.

Concentration of neuron-specific enolase and S100 protein in the subretinal fluid of rhegmatogenous retinal detachment.

BACKGROUND: Neuron-specific enolase and S100 protein are markers of neuronal lysis. To assess the neuronal suffering in rhegmatogenous retinal detachment we quantified neuron-specific enolase and S100 protein in the subretinal fluid. METHODS: The puncture was performed in the sclera with a Merseture 5/0 round needle, and the fluid was collected with a glass capillary tube. Twelve subretinal fluid samples were obtained from 12 eyes with rhegmatogenous retinal detachment undergoing retinal detachment surgery. Vitreous from ten eyes with macular hole or epimacular membrane served as negative control group, and vitreous collected during cornea procurement from ten deceased patients served as positive control group. RESULTS: The mean concentration of neuron-specific enolase (in nanogrammes per millilitre) was 602 in the subretinal fluid of rhegmatogenous retinal detachment, 10.2 in the serum of these patients, 2.9 in the vitreous of the negative control group, and 364 in the positive control group. The mean concentration of S100 protein (in nanogrammes per millilitre) was 104 in the subretinal fluid of rhegmatogenous retinal detachment, <0.1 in the serum of these patients and in the vitreous of the control negative group, and 11.18 in the positive control group. CONCLUSION: Neuron-specific enolase (NSE) and S100 are known to be good markers of brain stress and, thus, are good markers of retinal stress.

Pharmacokinetics of mycophenolic acid in kidney transplant patients receiving sirolimus versus cyclosporine.

INTRODUCTION: Mycophenolic acid (MPA) pharmacokinetics exhibit large variability in transplant recipients and may be altered due to concurrent immunosuppressants. Little is known about the influence of sirolimus (SRL) on MPA pharmacokinetics in kidney transplant patients. METHODS: We studied the areas under concentration-time curves (AUC) for MPA in 15 patients receiving immunosuppression combining SRL with mycophenolate mofetil (MMF). The pharmacokinetic measurements were performed in all patients using three MMF dosing regimens (0.5 g twice a day, 0.75 g twice a day, 1 g twice a day). Similar blood AUC profiles were also sampled from 12 patients treated with a fixed dose of MMF 1 g twice a day and cyclosporine (CsA). MPA was measured using HPLC; the AUC0-12 of MPA was determined by the trapezoidal method using four sampling time points: C0, C1, C3, C5. RESULTS: While patients on SRL were receiving 0.75 g MMF twice a day, mean AUC0-12 and C0 values of MPA were comparable to those of patients receiving CsA and 1 g MMF twice a day (54.1 +/- 17.6 and 3 +/- 1.87 vs 51.7 +/- 16.7 mg.h/L and 2.76 +/- 1.57 mg/L, respectively). On the other hand, 0.5 g MMF twice a day with SRL therapy resulted in AUC0-12 and C0 values of MPA of 32.3 +/- 12.6 mg.h/L and 2.32 +/- 1.72 mg/L, respectively, whereas, 1 g MMF twice a day with SRL resulted in AUC0-12 and C0 values of MPA of 70.9 +/- 19.3 mg.h/L and 4.7 +/- 2.44 mg/L, respectively. CONCLUSIONS: These findings demonstrate that MPA exposure in the presence of SRL is higher than that with CsA. It appears that the MMF dose should be reduced to 0.75 g twice a day in patients receiving SRL to obtain AUC0-12 of MPA levels comparable to that in patients treated with CsA and MMF 1 g twice a day.

Short-term pharmacokinetics and brain distribution of mecamylamine as a preliminary to carbon-11 labeling for nicotinic receptor investigation.

As a preliminary to development and evaluation of labeled mecamylamine as a potential in vivo imaging ligand for human central nicotinic receptors (nAchRs), this work was intended to determine whether the pharmacokinetic properties of mecamylamine are suitable for experimental studies using (11)C-radiolabeled mecamylamine preliminary to positron emission tomography (PET) in humans. An original gas chromatographic method for rapid and simple determination of mecamylamine in biological samples was developed and validated (within run precision, 3.8-5.2%; between assay variation, 5.3-6.9%; assay accuracy, 5.6-11.8%). The results of the pharmacokinetic investigation in the rat demonstrated a very fast clearance of mecamylamine from blood [half-life, 1.2 h; clearance (CL), 1.2 L/kg/h) concomitant with an uptake that was higher in kidney, intermediate in lung, and lower in heart, liver, and brain. Brain tissue kinetics of mecamylamine showed a similar pattern for all the regions, with a rapid increase followed by a plateau after 15 min. This plateau differed according to the region of the brain; it was higher in colliculi, hippocampus, and cortex (area of high density of nAchRs) than in cerebellum or white matter (area with a limited population of nAchRs). No other lipophilic metabolites that were able to disturb the specific binding to nAchRs were identified during the investigation. Thus, mecamylamine shows peculiar qualities making it a good candidate for carbon-11 labeling for experimental studies in view of final PET imaging.

Pharmacokinetics of antifungal agents in onychomycoses.

Onychomycosis is caused by infection by fungi, mainly dermatophytes and nondermatophyte yeasts or moulds; it affects the fingernails and, more frequently, the toenails. Dermatophytes are responsible for about 90 to 95% of fungal infections. Trichophyton rubrum is the most common dermatophyte; Candida albicans is the major nondermatophyte yeast. Although topical therapy of onchomycosis does not lead to systemic adverse effects or interactions with concomitantly taken drugs, it does not provide high cure rates and requires complete compliance from the patient. At present there are 3 oral antifungal medications that are generally used for the short term treatment of onychomycosis: itraconazole, terbinafine and fluconazole. The persistence of these active drugs in nails allows weekly administration, reduced treatment or a pulse regimen. Good clinical and mycological efficacies are obtained with itraconazole 100 to 200 mg daily, terbinafine 250mg daily for 3 months, or fluconazole 150 mg weekly for at least 6 months. Itraconazole is a synthetic triazole with a broad spectrum of action. It is well absorbed when administered orally and can be detected in nails 1 to 2 weeks after the start of therapy. The nail : plasma ratio stabilises at around 1 by week 18 of treatment. Itraconazole is still detectable in nails 27 weeks after stopping administration. Nail concentrations are higher than the minimum inhibitory concentration (MIC) for most dermatophytes and Candida species from the first month of treatment. The elimination half-life of itraconazole from nails is long, ranging from 32 to 147 days. Terbinafine is a synthetic allylamine that is effective against dermatophytes. Terbinafine is well absorbed from the gastrointestinal tract, and the time to reach effective concentrations in nail is 1 to 2 weeks. The half-life is from 24 to 156 days, explaining the observed persistence of terbinafine in nails for longer than 252 days. Fluconazole is a bis-triazole broad spectrum antifungal with high oral bioavailability. The uptake of fluconazole by nail increases with the length of treatment, and nail : plasma ratios are generally 1.5 to 2 at steady state. Fluconazole concentrations exceed the MIC for Candida species soon after the start of treatment. Fluconazole concentrations fall slowly after the drug is stopped, with a half-life of 50 to 87 days, and fluconazole is still detectable in nails 5 months after the end of treatment. All these drugs are potent inhibitors of cytochrome P450 (CYP) enzymes and may increase the plasma concentrations of concomitantly used drugs. Itraconazole inhibits CYP3A4. Fluconazole inhibits CYP3A4, but to a lesser degree than itraconazole, CYP2C9 and CYP2C19. Terbinafine inhibits CYP2D6.

Localization of neurotensin NTS2 receptors in rat brain, using.

The brain localization of the neurotensin receptor NTS2 was studied with [3H]levocabastine, using an autoradiographic procedure. This study suggests that NTS2 receptors are mainly intracellular. High densities of binding sites were observed in the cingulate, insular, temporal, occipital, enthorhinal cortex, amygdaloid complex, septohippocampal nuclei, medial thalamus, mammillary bodies and superior colliculi; a moderate labelling was observed in the anterior and medial hippocampus, olfactory tubercle, hypothalamus, periaqueductal gray matter, caudate putamen, nucleus accumbens, septum, lateral thalamus, dorsal raphe nucleus and cerebellum; finally, a low labelling was apparent in the ventral tegmentum area and substantia nigra. Thus it appears that NTS2 receptors are particularly abundant in the cerebral cortex, the limbic areas and some areas involved in pain perception.

Developmental changes of (3)H-labelled mu-opioid receptors in brainstems of intra-uterine growth-restricted rats.

The opioid mu-system is involved in brainstem-mediated respiratory control. Infants with intra-uterine growth restriction (IUGR) have more respiratory disorders in the early postnatal period. Using [(3)H]DAGO, a mu-selective ligand, and a computer-based image analysis of autoradiography, we compared the ontogeny and distribution of mu-opioid binding sites in the brainstem of IUGR and control rats in utero (E21), at birth (P0) and on postnatal days 1 (P1), P7, P10, P14 and P21. The ontogeny pattern was found to be similar in both groups. The density of the binding sites, which was low in E21, increased at P0, slightly declined at P1 and remained relatively constant thereafter. The distribution of DAGO-binding sites, also similar in both groups, was heterogeneous and was much denser in the dorsal areas of medulla and pons. In particular, binding sites were highly concentrated in nuclei involved in the cardio-respiratory function. However, DAGO-binding density was higher at all ages (except for P0 and P1) in IUGR than in control rats. Taken together, these results give at least a partial explanation for the effects of IUGR which lowers the Apgar score at birth and raises the incidence of respiratory disorders in infants.

Operative stress response is reduced after laparoscopic compared to open cholecystectomy: the relationship with postoperative pain and ileus.

Our objective was to determine the least invasive surgical procedure; to do this we compared postoperative pain, duration of ileus, and level of neurohormonal stress response after laparoscopic cholecystectomy (LC) and open cholecystectomy (OC). Postoperative recovery of patients was faster after LC than OC but comparison of the neurohormonal stress response after laparoscopic and open surgical procedures revealed conflicting results. Forty-one consecutive patients with noncomplicated gallstones were randomized for LC (N = 25) and OC (N = 16). The stress level was evaluated in patients before surgery by the Hamilton anxiety scale. Postoperative pain was assessed by a visual analogic scale (VAS) pain score and by the amount of analgesic drugs (propacetamol) administered, while the duration of ileus was determined by the delay between surgery and the time to first passage of flatus as well by the colonic transit time (CTT) measured by radiopaque markers. Plasma concentrations of anti-diuretic hormone (ADH), adrenocorticotropic hormone (ACTH), beta-endorphin (BE), neurotensin (NT), and aldosterone (Ald) were measured before and during surgery as well as 2 and 5 hr after the surgery (D0) and on the day following surgery (D1). Urinary cortisol (uCOR) and urinary catecholamine metabolites were assessed before surgery, during D0, and on D1. Patient characteristics, the duration of surgery, and the doses of anesthetic drugs were not different in LC and OC. In LC patients the VAS pain score and the doses of postoperative antalgics were lower (P < 0.05), the time to first passage of flatus was shorter (P < 0.001), and the CTT tended to be shorter (54 +/- 12 hr vs 81 +/- 17) compared to OC patients. Patients who required the highest doses of postoperative antalgics had the longest delay to first passage of flatus (P < 0.01). During surgery, all neurohormonal parameters increased compared to the preoperative period (P < 0.05), and only plasma NT concentrations were lower during LC than OC (P < 0.05). During the postoperative period, ACTH, BE, Aid, catecholamines, and uCOR concentrations were lower in LC than in OC (P < 0.05). Concentrations of hormonal parameters were higher when the duration of surgery increased (P < 0.05). A greater need for propacetamol to relieve pain was associated with a greater increase in BE, ACTH, and urinary catecholamine levels (P < 0.05-P < 0.005). When the time to first passage of flatus was delayed, levels of BE, ACTH, and catecholamines and NT concentrations were increased (P < 0.05-P < 0.005). In conclusion, LC is less invasive because this surgical procedure induces a shorter neurohormonal stress response than OC, even if the peroperative response is not different. Postoperative pain levels and the duration of ileus are associated with BE, ACTH, and catecholamine levels and NT concentrations, suggesting the importance of hormones in postoperative functional recovery.