Multiparameter Optimization of Naphthyridine Derivatives as Selective α5-GABAA Receptor Negative Allosteric Modulators.

The discovery and characterization of novel naphthyridine derivatives with selective α5-GABAAR negative allosteric modulator (NAM) activity are disclosed. Utilizing a scaffold-hopping strategy, fused [6 + 6] bicyclic scaffolds were designed and synthesized. Among these, 1,6-naphthyridinones were identified as potent and selective α5-GABAAR NAMs with metabolic stability, cardiac safety, and beneficial intellectual property (IP) issues. Relocation of the oxo acceptor function and subsequent modulation of the physicochemical properties resulted in novel 1,6-naphthyridines with improved profile, combining good potency, selectivity, ADME, and safety properties. Besides this, compound 20, having the most balanced profile, provided in vivo proof of concept (POC) for the new scaffold in two animal models of cognitive impairment associated with schizophrenia (CIAS).

Phenotypical Screening on Neuronal Plasticity in Hippocampal-Prefrontal Cortex Connectivity Reveals an Antipsychotic with a Novel Profile.

Dysfunction in the hippocampus-prefrontal cortex (H-PFC) circuit is a critical determinant of schizophrenia. Screening of pyridazinone-risperidone hybrids on this circuit revealed EGIS 11150 (S 36549). EGIS 11150 induced theta rhythm in hippocampal slice preparations in the stratum lacunosum molecular area of CA1, which was resistant to atropine and prazosin. EGIS 11150 enhanced H-PFC coherence, and increased the 8−9 Hz theta band of the EEG power spectrum (from 0.002 mg/kg i.p, at >30× lower doses than clozapine, and >100× for olanzapine, risperidone, or haloperidol). EGIS 11150 fully blocked the effects of phencyclidine (PCP) or ketamine on EEG. Inhibition of long-term potentiation (LTP) in H-PFC was blocked by platform stress, but was fully restored by EGIS 11150 (0.01 mg/kg i.p.), whereas clozapine (0.3 mg/kg ip) only partially restored LTP. EGIS 11150 has a unique electrophysiological profile, so phenotypical screening on H-PFC connectivity can reveal novel antipsychotics.

Fragment-Based Optimization of Dihydropyrazino-Benzimidazolones as Metabotropic Glutamate Receptor-2 Positive Allosteric Modulators against Migraine.

Our previous scaffold-hopping attempts resulted in dihydropyrazino-benzimidazoles as metabotropic glutamate receptor-2 (mGluR2) positive allosteric modulators (PAMs) with suboptimal drug-like profiles. Here, we report an alternative fragment-based optimization strategy applied on the new dihydropyrazino-benzimidazolone scaffold. Analyzing published high-affinity mGluR2 PAMs, we used a pharmacophore-guided approach to identify suitable growing vectors and optimize the scaffold in these directions. This strategy resulted in a new fragment like lead (34) with improved druglike properties that were translated to sufficient pharmacokinetics and validated proof-of-concept studies in migraine. Gratifyingly, compound 34 showed reasonable activity in the partial infraorbital nerve ligation, a migraine disease model that might open this indication for mGluR2 PAMs.

Retinal Nerve Fiber Layer Thickness and Oxidative Stress Parameters in Migraine Patients without Aura: A Pilot Study.

BACKGROUND: Migraine is one of the most common disorders and its pathophysiological mechanisms are still under research, oxidative stress being emphasized as an important contributor. This study aimed to analyze the retinal nerve fiber layer (RNFL) thickness and oxidative/anti-oxidant balance in migraine patients. METHODS: Two groups of subjects were evaluated: a group of patients with migraine and a control group of healthy volunteers. RNFL thickness was assessed for all subjects by the ocular coherence tomography spectral domain (OCT-SD). The oxidative stress parameter, namely nitric oxide (NOx), malondialdehyde (MDA), and total oxidative stress (TOS) were assessed. The antioxidant capacity of plasma was evaluated by assessing the level of catalase, and total anti-oxidative (TOS) capacity. Migraine severity was graded using the Migraine Disability Assessment Score (MIDAS) questionnaire. RESULTS: All the oxidative stress parameters (NOx, MDA, and TOS) were significantly increased, and both parameters for anti-oxidative status were significantly decreased in the migraine group compared with the control group (p < 0.0001). Significant correlations with all the quadrants and different oxidative stress parameters were found, most involved being temporal quadrant. A significant positive correlation between catalase and macular RNFL thickness (inner ring, temporal quadrant) in migraine patients, for both eyes, was observed (p = 0.014 for the right eye and p = 0.12 for the left eye). CONCLUSION: The assessment of the oxidative stress/anti-oxidative balance together with RFLN thickness can constitute a promising method to evaluate the progression of the diseases. It can also contribute to the estimation of the efficiency of various therapies targeting oxidative stress and associated inflammation.

Discovery of dihydropyrazino-benzimidazole derivatives as metabotropic glutamate receptor-2 (mGluR2) positive allosteric modulators (PAMs).

A scaffold hopping strategy converted the known 1-[(1-methyl-1H-imidazol-2-yl)methyl]-4-phenylpiperidine core (1 and 2) by cyclization to a fused [6 + 5+6] membered heterocyclic mGluR2 PAM scaffold. Pharmacophore guided structure-activity relationship (SAR) studies resulted in a series of potent and metabolically stable mGluR2 PAMs. A representative optimized compound (95) having the most balanced profile, demonstrated efficacy in the PCP-induced hyper-locomotion model in mice that revealed the new chemotype being a promising PAM lead targeting mGluR2 receptors and providing support for further translational studies.

Fragment Based Optimization of Metabotropic Glutamate Receptor 2 (mGluR2) Positive Allosteric Modulators in the Absence of Structural Information.

Metabotropic glutamate receptor 2 (mGluR2) positive allosteric modulators (PAMs) have been implicated as potential pharmacotherapy for psychiatric conditions. Screening our corporate compound deck, we identified a benzotriazole fragment (4) that was rapidly optimized to a potent and metabolically stable early lead (16). The highly lipophilic character of 16, together with its limited solubility, permeability, and high protein binding, however, did not allow reaching of the proof of concept in vivo. Since further attempts on the optimization of druglike properties were unsuccessful, the original hit 4 has been revisited and was optimized following the principles of fragment based drug discovery (FBDD). Lacking structural information on the receptor-ligand complex, we implemented a group efficiency (GE) based strategy and identified a new fragment like lead (60) with more balanced profile. Significant improvement achieved on the druglike properties nominated the compound for in vivo proof of concept studies that revealed the chemotype being a promising PAM lead targeting mGluR2 receptors.

Biomimetic Synthesis of Drug Metabolites in Batch and Continuous-Flow Reactors.

A medium-throughput screening (MTS) of biomimetic drug metabolite synthesis is developed by using an iron porphyrin catalyst. The microplate method, in combination with HPLC-MS analysis, was shown to be a useful tool for process development and parameter optimization in the production of targeted metabolites and/or oxidation products of forty-three different drug substances. In the case of the biomimetic oxidation of amiodarone, the high quantity and purity of the isolated products enabled detailed HRMS and NMR spectroscopic studies. In addition to identification of known metabolites, several new oxidation products of the drug that was studied were characterized. Fast degradation and poor recovery of the catalyst under batch conditions was overcome by immobilization of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin iron(III) chloride (FeTSPP) on the surface of 3-aminopropyl-functionalized silica by electrostatic interaction. The supported catalyst was successfully applied in a packed-bed reactor under continuous-flow reaction conditions for the large-scale synthesis of amiodarone metabolites.

Musculoskeletal ultrasound guided manoeuvres - a security profile.

BACKGROUND: In daily rheumatology clinical practice, routine interventional musculoskeletal ultrasound (MSUS) guided maneuvers such as aspiration, intraarticular or periarticular drug injections require efficient cleaning and disinfection methods for both transducer and patient's skin. AIM: To study the efficacy of probe and skin disinfection measures after using simple protocols, to identify the prevalence of septic and other drug related side effects after MSUS guided interventions and to quantify the total procedure time. MATERIAL AND METHODS: Recruitment of consecutive patients with different joint/ periarticular MSUS guided interventions was made in 3 medical centers. Bacterial load was determined on the transducers footprint after dry cleaning with the removal of any gel trace and on patients' skin after rigorous skin disinfection with either Bethadine or alcohol 70° and Bethadine. Non-sterile gel was used as an ultrasound transmission medium. The time spent for some of the invasive procedures was quantified. RESULTS: Nine hundred and ninety eight MSUS guided interventional maneuvers were performed in 945 patients with inflammatory and degenerative musculoskeletal pathologies. Staphylococcus epidermidis was identified in 13.33% cases of the skin bacterial load analysis and in 37.50% cases of the footprint analysis. In two patients pathogenetic germs were detected on the skin. No septic post-procedural complications were reported. In 0.6% of the cohort other side effects occurred: aseptic osteonecrosis, skin depigmentation at injection site and iatrogenic microcristaline reactions. The median time frame dedicated to the intervention was 6 minutes. CONCLUSION: Rigorous transducer dry cleaning and Bethadine / Bethadine and alcohol 70° skin disinfection are efficacious methods. The risk for septic complications and other drug related side effects related to MSUS guided injections is very low in this context. A correct injection technique must accompany the previous requests. Rapid and safe interventional maneuvers reduce the risks and control the costs of the healthcare system.

Examination of nasopharyngeal and tracheal somatosensory evoked potential recordings in dogs.

OBJECTIVE: To investigate the value of nasopharyngeal and tracheal recordings of somatosensory evoked potentials (SSEP) in anesthetized dogs. ANIMALS: 10 healthy mixed-breed dogs (5 males and 5 females). PROCEDURE: Square-ware electrical stimuli (50 microseconds duration, 4Hz) were delivered through bipolar surface electrodes to the median nerve of the right forelimb with 7 to 12 mA constant current. The SSEP were recorded with soft electrodes placed on the epipharynx and dorsal wall of the trachea, respectively. Traditional scalp and neck recordings of SSEP were also performed, using SC-inserted needle electrodes. The potentials recorded dorsally and ventrally from the neuraxis were compared to assess the application of these signals for intraoperative neurophysiologic monitoring. RESULTS: Electrical stimulation of the median nerve resulted in multiphasic potentials recorded from all 4 recording sites. Latency and phase shifts were observed between the far-field potentials placed ventrally and dorsally from the neuraxis. CONCLUSIONS AND CLINICAL RELEVANCE: Potentials recorded with nasopharyngeal and tracheal electrodes are regarded suitable for intraoperative neurophysiologic monitoring in anesthized dogs.

Urinary N-acetyl-beta-D-glucosaminidase in epileptic children treated with antiepileptic drugs.

AIM: To investigate the effect of prolonged use of antiepileptic drugs on renal function in children. METHODS: Prospective study of 72 children (aged 3-18 years) with epilepsy, on either monotherapy (n = 44) or combined therapy (n = 28). The length of treatment varied from 1 to 13 years. Drugs used were valproic acid, carbamazepine, ethosuximide, clonazepam, clobazepam, and vigabatrin. RESULTS: In 65 patients plasma concentrations of the drugs were in the therapeutic range. In the remaining seven, plasma concentrations were slightly high. In 33 patients urinary N-acetyl-beta-D-glucosaminidase (NAG) activity was raised. The incidence of pathological NAG indices was significantly higher in the combined therapy group than in the monotherapy group. There were also significant differences in the NAG indices of patients depending on the duration of therapy. CONCLUSIONS: Results suggest that chronic use of some antiepileptic drugs-in spite of normal blood concentrations-may alter tubular function, and the dysfunction may result in clinical symptoms. Therefore, we recommend screening of tubular function in these patients.

[Alkaline phosphatase level and bone density in Scheuermann's disease and in adolescent idiopathic scoliosis]. / Az alkalikus foszfatáz-szint és csontsúrúség Scheuermann-kórban és adolescens idiopathiás scoliosisban.

Authors made a comparison between 167 suffers from Scheuermann's disease (SD), 70 adolescence idiopathic scoliosis (AIS) and 132 age, sex, height, weight, pubertal developmental stages (Tanner stages) matched controls. The height percentile in 130 cases was also determined. The bone mineral density (BMD) was measured by pQCT on the non dominate sided radial bone. The alkaline phosphatase (AP) level increased at the beginning of puberty and in the puberty in SD. In SD the trabecular Z-score of BMD was significantly decreased in Tanner stage 1 to 4 in both boys and girls. It was not found any significance difference, however, in Tanner stage 5, while in AIS girl no significance decrease of BMD was found. In SD good correlation could be demonstrated between increase in AP and decrease in trabecular Z score r = 0.2, while did not correlate with height percentile. The AP level's increase, and radiomorphometric data of SD severity (intervertebral space narrowing and antero-posterior diameter increase of vertebral body) shows a significant correlation with decreased trabecular Z-score in the period of prepuberty.

Hungarian multicentre epidemiologic study of the warning and initial symptoms (prodrome, aura) of epileptic seizures.

We carried out a Hungarian multicentre study to assess the frequency of the occurrence of warning symptoms preceding epileptic seizure. The data of 562 patients with epilepsy out of a total of 1124 were analysed on the basis of questionnaires filled in under standard conditions. About 50% of the patients experienced warning symptoms before a smaller or greater part of their seizures. Their appearance was fairly consistent and became mainly manifested in the form of headache, epigastric sensation and dysphoria. In relation to epileptological basic data, it was found that warning symptoms appeared primarily in focal epilepsies and among them they mainly preceded generalized tonic clonic and complex partial seizures. Between the warning symptom and the onset of the seizure there was usually a longer interval during which (and generally also during the warning symptom) the patient remained able to act. About 20% of the patients enrolled in the study tried to inhibit the onset or mitigate the course of the seizure and about 10% judged their spontaneous activity carried out in that direction to be successful. The frequency of the occurrence of independent prognostic symptoms not followed by a seizure was relatively low, and among epileptics with warning symptoms the incidence of seizures occurring without a preceding event was not high either. Based on our experiences, we have drawn the conclusion that, in a significant part of epileptic patients, the warning symptoms render possible the supplementation of the therapy by the development of seizure-inhibiting or seizure-avoiding behaviour or activity.

[Transient neonatal myasthenia gravis]. / Transitorikus újszülöttkori myasthenia gravis.

Authors reported about their experiences with newborn infants, who had transient myasthenia gravis; one disease developed in the fetal, others 10 in the early neonatal age. Direct correlation was found between the development of maternal polyhydramnios and the severity symptoms in newborns: risk of neonatal myasthenia gravis increased at these infants. Specific treatment included blood exchange transfusions and pyridostigmin (Mestinon) medication for 2-10 weeks. Five transient myasthenia gravis responded readily to blood exchange transfusions. Authors pointed out that in the early neonatal period the aetiology of an obscure respiratory inadequacy and hypoventilation might be regarded as transient myasthenia gravis.

The role of free radicals in the pathogenesis of amiodarone toxicity.

INTRODUCTION: In vitro and in vivo studies were performed to elucidate the pathogenesis of amiodarone toxicity. METHODS AND RESULTS: Rats were treated with amiodarone alone (500 mg/kg body weight per day) or together with antioxidants (silibinin or MTDQ-DA: 50 mg/kg body weight per day) or with either antioxidant alone. They received amiodarone for 30 days and antioxidant for 33 days (3 days pretreatment). In vitro, amiodarone induced a dose-dependent chemiluminescence signal, which was inhibited by the two dihydroquinolin-type antioxidants (MTDQ-DA, CH 402). Chemiluminometric results from liver homogenate demonstrated that simultaneous treatment with silibinin partially prevented the liver homogenate superoxide anion radical scavenger capacity decreasing effect of amiodarone. Amiodarone treatment caused a significant increase of NADPH and Fe3+ induced lipid peroxidation in the liver microsomal fraction, which antioxidants (silibinin, MTDQ-DA) were unable to prevent. Light microscopy of the lung tissue in amiodarone-treated rats showed accumulation of foamy macrophages with thickening of the interalveolar septa, pneumonitis, and variable interstitial fibrosis. Antioxidant treatment did not prevent these changes. Electron micrographs of lung from amiodarone-treated rats showed lysosomal phospholipoidosis, intralysosomal electron dense deposits, and increased lysosome number and size. In contrast to rats treated with amiodarone alone, those treated with both amiodarone and silibinin had significantly fewer lysosomes (P < 0.01); the lysosome size, shape, and internal characteristics remained the same. Simultaneous treatment with silibinin and amiodarone decreased lysosomal phospholipoidosis compared to amiodarone treatment alone. Simultaneous treatment with MTDQ-DA and amiodarone did not show any beneficial effect. Pulse radiolysis and cobalt 60-gamma (60Co-gamma) radiolysis studies showed that the main free radical product in a reducing environment was a very reactive aryl radical formed after the partial deiodination of the amiodarone molecule. The radiosensitizing effect of amiodarone was also verified in rat liver microsomal preparations using in vivo amiodarone with or without MTDQ-DA pretreatment and 60Co-gamma irradiation with or without the in vitro addition of antioxidants (CH 402, MTDQ-DA). In vivo, the MTDQ-DA treatment also had a radiosensitizing effect; however, the in vitro addition of both antioxidants resulted in a radioprotective effect. The aryl radical also may emerge in vivo during the metabolism of amiodarone. CONCLUSION: These observations suggest that amiodarone in vitro and in vivo generates free radicals that may play a role in the pathogenesis of amiodarone toxicity beside other well-established mechanisms, and antioxidants may have a partial protective effect against amiodarone toxicity.

[Acquired epileptic aphasia--Landau-Kleffner syndrome]. / Szerzett epilepsziás aphasia--Landau-Kleffner-syndroma.

Authors report about a girl with Landau-Kleffner syndrome. After the history of normal developmental milestones at the age of five-and-half year the patient had absence seizures, and marked receptiv and expressiv aphasia developed gradually. She was found to have Landau-Kleffner syndrome. This entity initially can be regarded as deafness or psychiatric reaction. The seizure activity usually has a favorable outcome, the aphasia can fluctuate for years. The improvement is more likely in promptly treated cases.

Substituent effects in the free radical reactions of silybin: radiation-induced oxidation of the flavonoid at neutral pH.

Silybin dihemisuccinate sodium salt, a flavonoid used in human therapy of liver dysfunction, has an inhibitory effect in vivo on radiation-induced deactivation of enzymes and peroxidation of membrane lipids in rat liver microsomes. The reactivity of silybin and its phenolic OH groups towards free radicals (OH, N3., (SCN)2.-, Cl3CO2.) in aqueous solution was studied by pulse radiolysis. Absorption spectra for the phenoxyl-type radicals were assigned using structurally similar models. The one-electron reduction potential for silybin at pH 7 (E07 = 0.76 V), determined using the p-methoxy-phenoxyl/phenolate redox couple as reference standard (E07 = 0.72 V, Lind et al. 1990), is related to the 3'-methoxy-4'-OH structure, the exclusive target for one-electron oxidation at pH 7, while the 7-OH and 5-OH groups are prevented from oxidation by 4-keto substitution and intramolecular H-bonding, respectively. The free radical reactivity of silybin compares favourably with poly-OH-substituted flavonoids; however, the latter compounds have been reported to generate potentially toxic oxygen species at a biologically relevant pH.

[Possibilities of antioxidant therapy in the prevention of side effects of amiodarone]. / Az antioxidáns therapia lehetöségei az amiodaron mellékhatások megelözésében, illetve kivédésében.

The authors demonstrated the generation of a very reactive phenyl radical from amiodarone in a reducing molecular environment by pulse radiolysis study. The various antioxidants are probably not capable of preventing the generation of phenyl radical, as well as to protect against its damaging effects on the neighboring molecules. Electron microscopic studies from lung tissue of in vivo treated rats showed that the simultaneous Silibinin (a flavonoid type antioxidant) treatment with amiodarone decreased significantly the lysosomal phospholipoidosis induced by amiodarone compared with the amiodarone treated group, but it didn't prevent entirely the accumulation of lysosomal phospholipids. The in vitro lysosomal beta-glucuronidase enzyme release measured from the liver tissue of in vivo treated rats increased significantly on amiodarone treatment, the antioxidants used (Silibinin, and the dihydroquinoline type MTDQ-DA) didn't exert any favorable effect. The authors discuss in details the possible relationships between free radical reactions and lysosomal phospholipoidosis.

Neonatal periventricular leukomalacia: diagnosis and monitoring by real-time ultrasound.

Periventricular leukomalacia is a form of hypoxic-ischaemic encephalopathy developing in preterm babies. During the last year among 387 sonographically screened neonates 11 periventricular neonatal leukomalacia cases were found. Analysing their cases authors discuss its sonographic diagnosis and follow up. In the acute stage characteristic triangular shaped area of increased echogenicity appears at the external angle of the lateral ventricles, later regular shaped echo-free areas of cysts appear in that region. The diagnostic and prognostic significance of cranial sonography in periventricular leukomalacia is discussed.

Sonography of meningoencephalitis and ventriculitis in infancy.

On the basis of eleven own cases sonographic features of infant meningoencephalitis and ventriculitis are discussed. The characteristic findings are as follows: abnormal parenchymal echogenicity of brain, changes of the size and wall echogenicity of cerebral ventricles and that of cerebrospinal fluid echogenicity.

[Detection of increased intracranial pressure by transcranial Doppler sonography in infants]. / Intracranialis nyomásfokozódás kimutatása transcranialis Doppler-szonográfiával csecsemökorban.

The value of transcranial Doppler sonography is demonstrated in two infants with an elevation of intracranial pressure (ICP). One of them suffered from hydrocephalus and ICP increased because of her VP shunt-insufficiency. In the other case status epilepticus caused brain oedema and a rise in intracranial pressure. In both cases, transcranial Doppler sonography showed a decrease in blood flow (CBF) velocity and an increase in the Pourcelot index in the middle cerebral artery. Quick or gradual reduction of the ICP led to an increase in CBF velocity and a decrease in the Pourcelot index. On the basis of experiences of the authors, transcranial Doppler sonography is a valuable method of verifying the elevation of ICP. It is suitable for measuring the effect of treatment necessitated by the elevation of ICP. The method is non-invasive, quick and it can be freely repeated. Therefore it is applicable for monitoring the dynamic of ICP.