Expression of brain prolactin releasing peptide (PrRP) changes in the estrous cycle of female rats

The aim of this study was to determine whether spinal cord stimulation (SCS) modulates activity of lumbosacral spinal neurons receiving input from the urinary bladder. Extracellular potentials of L6-S2 spinal neurons were recorded in pentobarbital anesthetized, paralyzed and ventilated male rats. SCS (50 Hz, 0.2 ms, 3-5 min, 90% motor threshold) was applied on the dorsal column of L2-L3 and C1-C2 segments and significantly reduced excitatory responses of 18/25 (72%) and 13/19 (68%) lumbosacral neurons to noxious urinary bladder distension (UBD, > or =1.0 ml, 20 s), respectively. SCS affected spinal neurons with either high- or low-threshold responses to UBD. These results suggested that SCS might have a potential therapeutic effect for patients with hypersensitivity and/or pain of cystitis and other urinary bladder disorders.     

Common dynamics in temporal lobe seizures and absence seizures.

Similarities among the clinical features of complex partial temporal lobe seizures and absence (petit mal) seizures suggest shared underlying mechanisms, but dissimilar electrographic features of the two seizure types have cast doubt on common neuronal substrates. However, visual inspection and traditional approaches to quantitative analysis of the electroencephalogram and electrocorticogram, such as Fourier analysis, may not be appropriate to identify and characterize the highly non-linear mechanisms likely to underlie ictal events. We previously introduced a technique, non-linear autoregressive analysis, that is designed to identify non-linear dynamics in the electroencephalogram [Schiff N. D. et al. (1991) Society of Neuroscience 21st Annual Meeting, 638.6; Schiff N. D. et al. (1995) Biol. Cybern. 72, 519-526, 527-533]. The non-linear autoregressive analysis technique is aimed at describing seizure discharges as a disturbance of synchrony at the level of neuronal circuits. In absence seizures, we showed that non-linear autoregressive analysis revealed a consistent "fingerprint" of these non-linearities in 3/s discharges within and across patients. Here, we investigate the possibility that non-linear autoregressive modeling of seizure records from patients with temporal lobe epilepsy might reveal common circuit mechanisms when compared with the non-linear autoregressive analysis fingerprint of absence seizures. Electrocorticographic records of seizure activity were obtained in four patients who had received subdural grids or strips implanted in preparation for epilepsy surgery. Decomposition of the multichannel data recorded from these patients by principal component analysis revealed that at least three to five independent "generators" were required to model the data from each patient. Non-linear autoregressive analysis of these extracted generators revealed non-linear dynamics in two patients. In both patients, the temporal aspects of these non-linearities were similar to the characteristic non-linearities identified in the non-linear autoregressive analysis fingerprint of absence seizures. In particular, both patients showed a non-linear interaction of signals 90 ms in the past with signals 150 ms in the past. This was the most prominent interaction seen in all patients with absence seizures (typical and atypical). These results suggest that seizures from some patients with temporal lobe epilepsy may share common underlying circuit mechanisms with those of absence seizures. Physiological interpretations of these results are considered and proposed mechanisms are placed into the context of the alterations of consciousness seen in both epilepsies.     

Cellular and network mechanisms of genetically-determined absence seizures

The absence epilepsies are characterized by recurrent episodes of loss of consciousness associated with generalized spike-and-wave discharges, with an abrupt onset and offset, in the thalamocortical system. In the absence of detailed neurophysiological studies in humans, many of the concepts regarding the pathophysiological basis of absence seizures are based on studies in animal models. Each of these models has its particular strengths and limitations, and the validity of findings from these models for the human condition cannot be assumed. Consequently, studies in different models have produced some conflicting findings and conclusions. A long-standing concept, based primarily from studies in vivo in cats and in vitro brain slices, is that these paroxysmal electrical events develop suddenly from sleep-related spindle oscillations. More specifically, it is proposed that the initial mechanisms that underlie absence-related spike-and-wave discharges are located in the thalamus, involving especially the thalamic reticular nucleus. By contrast, more recent studies in well-established, genetic models of absence epilepsy in rats demonstrate that spike-and-wave discharges originate in a cortical focus and develop from a wake-related natural corticothalamic sensorimotor rhythm. In this review we integrate recent findings showing that, in both the thalamus and the neocortex, genetically-determined, absence-related spike-and-wave discharges are the manifestation of hypersynchronized, cellular, rhythmic excitations and inhibitions that result from a combination of complex, intrinsic, synaptic mechanisms. Arguments are put forward supporting the hypothesis that layer VI corticothalamic neurons act as 'drivers' in the generation of spike-and-wave discharges in the somatosensory thalamocortical system that result in corticothalamic resonances particularly initially involving the thalamic reticular nucleus. However an important unresolved question is: what are the cellular and network mechanisms responsible for the switch from physiological, wake-related, natural oscillations into pathological spike-and-wave discharges? We speculate on possible answers to this, building particularly on recent findings from genetic models in rats.     

The distinction between absence petit mal and psychomotor seizures

A brief discussion of the manifestations of limbic lobe discharge as opposed to discharge in neocortical temporal lobe structures is given. The opinion is expressed that, apart from certain characteristic limbic auras, the manifestations of psychomotor epilepsy are those of inactivation of brain stem mechanisms subserving consciousness. A brief discussion of other manifestations of inactivation of brain stem mechanisms subserving various other functions, as seen in other clinical patterns of epileptic discharge, follows. Hippocampal sclerosis is put forth as the cause rather than the result of seizures in both the juvenile and the adult age groups. It is proposed that limbic lobe structures have a low threshold for initiating epileptic discharge when injured, are predisposed to injury and give rise to discharge which has preferential access to brain stem structures. It is stated that petit mal absences and psychomotor attacks are clinically indistinguishable. The further opinion is expressed that the 3 per second wave and spike EEG pattern associated with petit mal is an epiphenomenon dependent upon the maturational stage of development of the brain at the time when the causative lesion responsible for epilepsy is acquired. The view that the 3 per second wave and spike pattern is a direct correlate of the clinical manifestations of epilepsy, in those patients who show this pattern, is challenged. It is concluded that the pattern is the result of rostral brain stem discharge acting upon the cortex. The view is offered that two factors are necessary for the development of epilepsy: (1) an adequate pathological basis in the form of a cerebral lesion and (2) a greater or lesser predisposition toward inadequate biochemical mechanisms tending to check or control the spread of seizure discharge, the latter being in all probability at least partially genetically determined. It is concluded that triggering cortical foci exist in nearly all cases of epilepsy, though the participation of brain stem structures is essential to explain many of the clinical and EEG manifestations of the attack.     

Ingested (oral) SIRS peptide 1-21 suppresses type 1 diabetes in NOD mice.

Type 1 diabetes (T1D) is a chronic disorder that results from autoimmune destruction of the insulin-producing pancreatic beta cell. The nonobese diabetic (NOD) mouse is a model of the human autoimmune disease T1D. Soluble immune response suppressor (SIRS) is a nonspecific protein suppressor of immune response produced by immunomodulatory T cells stimulated by type I interferon (IFN). SIRS inhibits antibody responses in vivo, lipopolysaccharide (LPS)-induced fever, and delayed-type hypersensitivity (DTH) responses. Previous investigators have isolated the N-terminal sequence of SIRS protein consisting of 21 amino acids. Mice ingesting 1 microg SIRS peptide 1-21 showed significant delayed onset of T1D and a decreased frequency of T1D compared with mock-fed and 10-microg-fed mice and a significant decrease in islet inflammation. There were significant decreases in islet lymphocyte chemokine production of granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage inflammatory protein-1 gamma (MIP-1 gamma), regulated upon activation, normal T cell-expressed, and presumably secreted (RANTES), and stromal cell-derived factor-1 (SDF-1) in the SIRS-fed mice, factors important in migration of inflammatory cell into the islets. Ingested (oral) SIRS peptide inhibits clinical T1D by decreasing target organ cellular migration of islet destructive populations by suppression of islet lymphocyte chemokine secretion.     

Nanos2 suppresses meiosis and promotes male germ cell differentiation

In mouse fetal gonads, retinoic acid (RA) induces meiosis in the female germ cells, whereas the male germ cells never enter meiosis due to Cyp26b1-mediated RA metabolism. We show here that Nanos2 plays critical roles in the differentiation of male germ cells. We find that Nanos2 maintains the suppression of meiosis by preventing Stra8 expression, which is required for premeiotic DNA replication, after Cyp26b1 is decreased. We also demonstrate that Nanos2 activates a male-specific genetic program, which is supported by the inhibition of meiosis and the induction of male-type differentiation in female germ cells following the forced expression of Nanos2.     

Roles of the subthalamic nucleus and subthalamic HCN channels in absence seizures

Absence seizures consist of a brief and sudden impairment of consciousness. They are characterized by bilaterally synchronized spike and wave discharges (SWDs), which reflect abnormal oscillations in the thalamocortical loops. Recent studies have suggested that the basal ganglia are involved in generation of the SWDs, but their roles are poorly understood at the molecular and cellular levels. Here we studied the pathophysiological roles of the basal ganglia, using in vivo and in vitro measurements of tottering mice, a well-established model of absence epilepsy. We found that the membrane excitability in subthalamic nucleus (STN) neurons was enhanced in tottering mice, which resulted from reduced hyperpolarization-activated cyclic nucleotide-gated (HCN) channel activity. Pharmacological blockade and activation of HCN channel activity in vitro bidirectionally altered the membrane excitability of the STN neurons. Furthermore, these pharmacological modulations of HCN channel activity in the STN in vivo bidirectionally altered the mean SWD duration. In addition, STN deep brain stimulation modulated SWDs in a frequency-dependent manner. These results indicate that STN is involved in the rhythm maintenance system of absence seizures.     

The secretory leukocyte protease inhibitor (SLPI) suppresses cancer cell invasion but promotes blood-borne metastasis via an invasion-independent pathway

An invasion-independent pathway has been proposed as a novel mechanism in blood-borne metastasis, where tumour cells enveloped by sinusoidal tumour vessels enter the circulation without vascular invasion. We previously identified the secretory leukocyte protease inhibitor (SLPI) as a candidate gene responsible for this pathway. In this study, the functional role of SLPI in metastatic dissemination was investigated. We transfected the SLPI gene into a poorly metastatic clone of the MCH66 mouse mammary tumour cell line. Over-expression of SLPI promoted in vivo growth and spontaneous metastasis to the lung, whereas it suppressed invasive activity in vitro. The inoculated tumours of SLPI-transfectants exclusively induced a sinusoidal vasculature and subsequently produced endothelial-coated tumour emboli, which are morphological indices of the invasion-independent pathway. In addition, exogenous SLPI inhibited the migration activity through Matrigel of both tumour cells and human umbilical vein endothelial cells (HUVECs). In vivo angiogenesis assays also demonstrated that SLPI suppressed the migration of newly formed blood vessels. These results suggest that an anti-migratory effect of SLPI on tumour-associated endothelial cells may induce vascular remodelling to form a sinusoidal architecture, and consequently promote invasion-independent metastasis. This study provides a new model for metastasis, based on the mechanism regulated by anti-invasive factors, such as SLPI.     

E6-AP association promotes SOD1 aggresomes degradation and suppresses toxicity

Protein aggregation and ordered fibrillar amyloid deposition inside and outside of the central nervous system cells is the common pathologic hallmark of most aging-related neurodegenerative disorders. Dominant mutations in the gene encoding superoxide dismutase 1 (SOD1) protein are linked to familial amyotrophic lateral sclerosis (ALS), a neurodegenerative disease characterized by progressive degeneration of motor neurons, leading to muscle paralysis and death. The major histochemical hallmark in the remaining motor neurons of ALS is the intracellular accumulation of ubiquitinated inclusions consisting of insoluble aberrant protein aggregates. However, the molecular pathomechanisms underlying the process have been elusive. Here for the first time, we report that E6-AP, a homologous to E6-AP C terminus-type E3 ubiquitin ligase depleted in ALS mouse models before neurodegeneration. E6-AP coimmunoprecipitates with the SOD1 protein and is predominantly mislocalized in mutant SOD1-containing inclusion bodies. Overexpression of E6-AP increases the ubiquitination and facilitates degradation of SOD1 proteins. Finally, we show that the overexpression of E6-AP suppresses the aggregation and cell death mediated by mutated SOD1 proteins and cellular protective effect is more prominent when E6-AP is overexpressed along with Hsp70. These data suggest that enhancing the activity of E6-AP ubiquitin ligase might be a viable therapeutic strategy to eliminate mutant SOD1-mediated toxicity in ALS.     

T-type calcium channel blockers that attenuate thalamic burst firing and suppress absence seizures

Absence seizures are a common seizure type in children with genetic generalized epilepsy and are characterized by a temporary loss of awareness, arrest of physical activity, and accompanying spike-and-wave discharges on an electroencephalogram. They arise from abnormal, hypersynchronous neuronal firing in brain thalamocortical circuits. Currently available therapeutic agents are only partially effective and act on multiple molecular targets, including γ-aminobutyric acid (GABA) transaminase, sodium channels, and calcium (Ca(2+)) channels. We sought to develop high-affinity T-type specific Ca(2+) channel antagonists and to assess their efficacy against absence seizures in the Genetic Absence Epilepsy Rats from Strasbourg (GAERS) model. Using a rational drug design strategy that used knowledge from a previous N-type Ca(2+) channel pharmacophore and a high-throughput fluorometric Ca(2+) influx assay, we identified the T-type Ca(2+) channel blockers Z941 and Z944 as candidate agents and showed in thalamic slices that they attenuated burst firing of thalamic reticular nucleus neurons in GAERS. Upon administration to GAERS animals, Z941 and Z944 potently suppressed absence seizures by 85 to 90% via a mechanism distinct from the effects of ethosuximide and valproate, two first-line clinical drugs for absence seizures. The ability of the T-type Ca(2+) channel antagonists to inhibit absence seizures and to reduce the duration and cycle frequency of spike-and-wave discharges suggests that these agents have a unique mechanism of action on pathological thalamocortical oscillatory activity distinct from current drugs used in clinical practice.     

Strontium promotes cell proliferation and suppresses IL-6 expression in human PDL cells

This study was designed to investigate the effect of strontium on human PDL cells in vitro. Strontium is used to treat osteoporosis because of its bone formation promoting effect on osteoblast cells. This investigation presents evidence that strontium promotes PDL cell proliferation. Simultaneously, strontium suppresses the expression of the inflammation-promoting cytokine IL-6. The observed effect of strontium on PDL cells supports its use it in guided dental tissue regeneration.     

Morphometric changes and molecular mechanisms in rat models of idiopathic generalized epilepsy with absence seizures

The idiopathic generalized epilepsies (IGEs), constituting approximately a quarter of all epilepsy cases, are presumed to arise primarily from genetic abnormalities. A minority of cases have been identified to be caused by mutations in a single gene, but in the vast majority, mutations in multiple genes are presumed to contribute to the development of epilepsy. Two rat models of IGE with absence seizures, the Genetic Epilepsy Rats from Strasbourg (GAERS) and Wistar Albino Glaxo from Rijswijk (WAG/Rij), have proven valuable for translational research. These models closely mimic the behavioural, electrophysiological, and pharmacological aspects of the human condition, with the epilepsy phenotype for both likely to have polygenic determinants. Research in these models, using molecular and in vivo imaging approaches, has provided important insights into the pathophysiology of IGE. Molecular and imaging techniques have the potential to provide researchers with tangible biomarkers of disease progression and the effects of intervention, and also to provide fundamental information about the causation and epileptogenic processes associated with IGE. This review discusses the published literature concerning the molecular changes and morphometric abnormalities identified in these models, as well as their potential relevance for human IGE.     

A tyrosine-rich amelogenin peptide promotes neovasculogenesis in vitro and ex vivo

The formation of new blood vessels has been shown to be fundamental in the repair of many damaged tissues, and we have recently shown that the adult human periodontal ligament contains multipotent stem/progenitor cells that are capable of undergoing vasculogenic and angiogenic differentiation in vitro and ex vivo. Enamel matrix protein (EMP) is a heterogeneous mixture of mainly amelogenin-derived proteins produced during tooth development and has been reported to be sometimes effective in stimulating these processes, including in clinical regeneration of the periodontal ligament. However, the identity of the specific bioactive component of EMP remains unclear. In the present study we show that, while the high-molecular-weight Fraction A of enamel matrix derivative (a heat-treated form of EMP) is unable to stimulate the vasculogenic differentiation of human periodontal ligament cells (HPC) in vitro, the low-molecular-weight Fraction C significantly up-regulates the expression of the endothelial markers VEGFR2, Tie-1, Tie-2, VE-cadherin and vWF and markedly increases the internalization of low-density lipoprotein. Furthermore, we also demonstrate, for the first time, that the synthetic homolog of the 45-amino acid tyrosine-rich amelogenin peptide (TRAP) present in Fraction C is likely to be responsible for its vasculogenesis-inducing activity. Moreover, the chemically synthesized TRAP peptide is also shown here to be capable of up-regulating the angiogenic differentiation of the HPC, based on its marked stimulation of in vitro cell migration and tubule formation and of blood vessel formation assay in a chick embryo chorioallantoic membrane model ex vivo. This novel peptide, and modified derivatives, might thereby represent a new class of regenerative drug that has the ability to elicit new blood vessel formation and promote wound healing in vivo.     

Spontaneous eyelid movements (ELMS) during sleep are related to dream recall on awakening

The present study aimed to test whether spontaneous eyelid movements (ELMs) during stage 2 and rapid eye movement (REM) sleep are related to more frequent and vivid reports of visual mentation on awakening. Participants were awakened 15 s after an ELM was observed during ongoing REM and stage 2 sleep and immediately asked for a mentation report and to rate the visual vividness of any imagery they could remember. These reports were compared with control reports collected after a period of ELM quiescence before awakening (noELM). Significantly greater frequencies of imagery reports were collected after ELM awakenings compared with noELM awakenings from stage 2, but not REM sleep. When imagery was reported, imagery ratings were not significantly different between ELM and noELM conditions, regardless of sleep stage. The average amount of electroencephalogram (EEG) arousal 15 s after stage 2 awakenings was significantly higher in the ELM compared with noELM conditions. In addition, within the stage 2 ELM condition, EEG arousal was significantly higher when visual imagery was reported compared with reports without imagery; suggesting that the observed increase in imagery reporting from the stage 2 ELM condition could have been mediated by the level of brain arousal. Such arousal possibly provides better conditions to attend and recall previous mental activity from NREM sleep. However, there was no ELM/arousal effect within REM sleep, possibly because this state is already at maximum sleeping levels of arousal, attention and resulting dream recall.     

The delta EEG (sleep)-inducing peptide (DSIP)

A peptide which induces slow-wave EEG (sleep) after intraventricular infusion into the brain has been isolated from the extracorporeal dialysate of cerebral venous blood in rabbits submitted to hypnogenic electrical stimulation of the intralaminar thalamic area. It was shown by amino-acid analysis and sequence determination to be Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu and named Delta Sleep-Inducing Peptide (DSIP). This compound was synthesized as well as 5 possible metabolic products (1–8, 2–9, 2–8, 1–4 and 5–9), 2 nonapeptide analogues (with one and two amino-acids exchanged) and a related tripeptide (Trp-Ser-Glu). All 9 synthetic peptides were infused intraventricularly in rabbits (6 nmol/kg in 0.05 ml of CSF-like solution over 3.5 min) and tested under double-blind conditions. A total of 61 rabbits including controls were used. The EEG from the frontal neocortex and the limbic archicortex were subjected to direct fast-Fourier transformation and analyzed by an 1108 computer system. A highly specific delta and spindle EEG-enhancing effect of the synthetic DSIP could be demonstrated. The mean increase of EEG delta activity reached 35% in the neocortex and limbic cortex as compared to control animals receiving CSF-like solution or any of the other 8 peptides. The final chemical characterization of the synthetic DSIP revealed that only the pure -aspartyl peptide is highly active in contrast to its -Asp isomer. A neurohumoral modulating and programming activity was suggested.Abbreviations EEG Electroencephalogram - ECG Electrocardiogram - EPG Electropneumogram - SWS Slow-Wave Sleep = orthodox sleep = delta sleep - CSF cerebrospinal fluid - DSIP Delta Sleep-Inducing Peptide - DANSYL 5-dimethylaminonaphtalene sulfony - tlc thin-layer chromatography - GC Gas Chromatography - HPLC High Pressure Liquid Chromatography     

几种以皮层病灶起源的失神样癫痫发作患者的临床与脑电特征

目的：探讨几种由皮层病灶起源的失神样癫痫的发作分类,并就其临床与脑电特征进行分析讨论,为临床诊断失神样癫痫发作提供有价值的材料.方法：回顾性分析了我所近1年多来进行术前V-EEG监测到皮层病灶起源的24例具有明显失神样癫痫发作患者的临床、EEG及影像学资料.结果：24例中17例患者经头皮与颅内电极[皮层和（或）深部电极]描记EEG并进行了手术.失神发作时以额叶皮层起源放电者5例,颞叶7例,顶-枕叶5例 其余7例中4例属Lennox-Gastaut综合征,另3例因皮层多发病灶未进行手术.不同脑皮层部位起源的放电均可引起失神样发作,但其临床与脑电有各自的特点.脑电图出现3 Hz棘慢综合波时并非全是典型的失神样发作.结论： 失神样癫痫发作可分为全面性与部分性两大类,诊断失神样癫痫发作时应将EEG与临床资料进行综合分析,以免误诊.     

The effects of slow-wave sleep (SWS) deprivation and time of night on behavioral performance upon awakening

The aim of the present study is to evaluate the effects of selective SWS deprivation on the motor and sensory motor performance impairment immediately after awakening from nocturnal sleep at different times of the night. Ten normal males slept for 6 consecutive nights in the laboratory: one adaptation, two baseline, two selective SWS deprivation, and one recovery night. During the last 4 nights performance was assessed four times: (a) before sleep, as a baseline measure; (b) within 30 s from the first nighttime awakening, after 2 h of sleep; (c) within 30 s from the second nighttime awakening, after 5 h of sleep; (d) within 30 s from the final morning awakening. After each awakening, following a 3-min cognitive test, a simple Auditory Reaction Time task (ART, about 5 min) and a Finger Tapping Task (FTT, 3 min) were administered. Median of Reaction Times (RT) and of Intertapping Intervals (ITI), 10% fastest RT, 10% slowest RT, and number of misses were considered as dependent variables. The selective SWS deprivation was very effective: SWS percentage during both the deprivation nights was close to zero. This strong manipulation of SWS amount interacted with time-of-night factors in influencing sleep inertia. The SWS deprivation procedure caused a worsening of behavioral performance during the deprivation nights. as well as upon the final awakening of the recovery night. Behavioral performance slowing upon awakening is accounted for by: (1) a general decrement in overall response speed (median of RT); (2) an "optimum response shift", i.e., a decrease in speed of the fastest responses; (3) an increase of lapsing, with more marked response delays resulting in a further decrease in response speed in the "lapse domain". Finally, our results do not support the existence of a circadian rhythm of sleep inertia linked to body temperature rhythm.