Saccharomyces cerevisiae mutants lacking oxidative stress response genes were used to investigate... more Saccharomyces cerevisiae mutants lacking oxidative stress response genes were used to investigate which genes are required under normal aerobic conditions to maintain cellular redox homeostasis, using intracellular glutathione redox potential (glutathione E h ) to indicate the redox environment of the cells. Levels of reactive oxygen species (ROS) and mitochondrial membrane potentials (MMP) were also assessed by FACS using dihydroethidium and rhodamine 123 as fluorescent probes. Cells became more oxidised as strains shifted from exponential growth to stationary phase. During both phases the presence of reduced thioredoxin and the activity of glutathione reductase were important for redox homeostasis. Thioredoxin reductase contributed less during exponential phase when there was a strong requirement for active Yap1p transcription factor, but was critical during stationary phase. The absence of ROS detoxification systems, such as catalases or superoxide dismutases, had a lesser effect on glutathione E h , but a more pronounced effect on ROS levels and MMP. These results reflect the major shift in ROS generation as cells switch from fermentative to respiratory metabolism and also showed that there was not a strong correlation between ROS production, MMP and cellular redox environment. Heterogeneity was detected in populations of strains with compromised anti-oxidant defences, and as cells aged they shifted from one cell type with low ROS content to another with much higher intracellular ROS.
Pattern visual evoked potentials (VEPs) were recorded from the pial surface of the cat primary vi... more Pattern visual evoked potentials (VEPs) were recorded from the pial surface of the cat primary visual cortex prior to and following the intravenous administration of physostigmine, an agent which blocks the enzyme responsible for the breakdown of synaptically released acetylcholine. The control VEP was composed of a small initial positive deflection (P1), a subsequent large negative wave (N1) and a second large positive wave (P2). Following physostigmine, the amplitude of P1-N1 was diminished whereas that of N1-P2 increased. These effects were long lasting and were blocked by prior treatment with scopolamine, a result consistent with mediation by a muscarinic cholinergic pathway. Waveform subtraction revealed that the physostigmine-sensitive component had a slow, negative polarity waveform while the physostigmine-insensitive component was also slow, but positive in polarity. The fundamental nature of these components remains to be assessed. Nevertheless, the results indicate that waveforms of different polarity combine algebraically to yield the conventional VEP.
Electroencephalography and Clinical Neurophysiology/Electromyography and Motor Control, 1995
Poster session 28. Epilepsy (1) decreased tracer accumulation in ~231-1omazenil SPECT indicate de... more Poster session 28. Epilepsy (1) decreased tracer accumulation in ~231-1omazenil SPECT indicate decreased BZr binding, we speculate that decreased GABAA/BZr is related to the basic mechanism of temporal lobe epilepsy.
Epileptic disorders : international epilepsy journal with videotape, 2007
Charles Bonnet syndrome (CBS) is a disorder characterized by the occurrence of complex visual hal... more Charles Bonnet syndrome (CBS) is a disorder characterized by the occurrence of complex visual hallucinations in patients with acquired impairment of vision and without psychiatric disorders. In spite of the high incidence of visual field defects following antero-mesial temporal lobectomy for refractory temporal lobe epilepsy, reports of CBS in patients who underwent this surgical procedure are surprisingly rare. We describe a patient operated on for drug-resistant epilepsy. As a result of left antero-mesial temporal resection, she presented right homonymous hemianopia. A few days after surgery, she started complaining of visual hallucinations, such as static or moving "Lilliputian" human figures, or countryside scenes, restricted to the hemianopic field. The patient was fully aware of their fictitious nature. These disturbances disappeared progressively over a few weeks. The incidence of CBS associated with visual field defects following epilepsy surgery might be underesti...
Epileptic disorders : international epilepsy journal with videotape, 2001
We investigated the electroclinical features of 12 patients with childhood absence epilepsy (CAE)... more We investigated the electroclinical features of 12 patients with childhood absence epilepsy (CAE), presenting with typical absence seizures associated with myoclonic manifestations of the face or neck. All patients underwent repeated and prolonged split-screen video-polygraphic EEG recordings. The polygraphic recordings and clinical correlations of the absence seizures were analysed. All patients presented with multi-quotidian, typical absence seizures. During the absences, the patients could show mild, rhythmic, myoclonic jerks involving facial areas (eyebrows, nostrils, perioral region, chin) or neck muscles (sternocleidomastoideus), with the same frequency as the spike-wave complexes. Polygraphic tracings demonstrated that the myoclonias were correlated to the spike component. Clinically, all patients showed a benign course, with complete seizure control under antiepileptic treatment. In the follow-up, 7 patients withdrew from treatment without relapse. We conclude that all our p...
Epileptic disorders : international epilepsy journal with videotape, 2008
We describe the case of an eight-year-old boy, who underwent a video-stereo EEG (SEEG) investigat... more We describe the case of an eight-year-old boy, who underwent a video-stereo EEG (SEEG) investigation for the presurgical assessment of drug-resistant epilepsy, related to a right fronto-lateral cortical dysplasia and who became seizure-free after epilepsy surgery. The unexpected finding of the investigations was that intracerebral, high frequency (50 Hz) electrical stimulation (HFS) triggered the emergence of automatic and involuntary forward-backward locomotion during a focal seizure while the boy was standing. This clinical manifestation was different from the chaotic motor activity described during epileptic wanderings. The stimulation of the same fronto-lateral region, while the patient was lying, produced only the subjective sensation that the legs were moving, although there was no physical manifestation of this. Human locomotion is an innate motor behavior that is normally due to the activation of the spinal network for locomotion (central pattern generator). The emergence of...
To estimate the prevalence of nocturnal frontal lobe epilepsy (NFLE) in the adults of two areas o... more To estimate the prevalence of nocturnal frontal lobe epilepsy (NFLE) in the adults of two areas of the Emilia-Romagna region (northeast Italy) and to describe the clinical features from a population-based perspective. Population-based retrospective cohort study including adults with NFLE. Two areas of the Emilia-Romagna region: the city of Bologna (330,901 adult residents) and five districts of the province of Modena (424,007). Prevalence day: December 31, 2010. Patients with NFLE collected from multiple databases of neurologic hub centers of the districts involved. Diagnostic criteria: clinical history of sleep related bizarre motor attacks and videopolysomnographic recording confirming the typical features of NFLE. Inclusion criteria for prevalence calculation: residence in one of the two geographic areas on the prevalence day and an "active" or "in remission with treatment" form of NFLE. Six subjects from Bologna and eight from Modena were included. Crude prevalence (per 100,000 residents) was 1.8 (95% confidence interval 0.7-4.0) in Bologna and 1.9 (0.8-3.7) in Modena. Similarly, the main clinical features were consistent: onset during adolescence (median age 11-13 y), mainly hyperkinetic seizures, nonlesional form in more than two-thirds of cases, an active form of epilepsy in more than two-thirds of cases. A family history of epilepsy was reported only for two patients. This epidemiologic study establishes that NFLE is a rare epileptic condition, fulfilling the definition for rare disease. Because of methodological limitations of our case ascertainment, the estimates we disclose must be considered the minimum prevalence.
Sudden unexpected death in epilepsy Sleep Obstructive sleep apnoea Autonomic system s u m m a r y... more Sudden unexpected death in epilepsy Sleep Obstructive sleep apnoea Autonomic system s u m m a r y The risk of sudden unexpected death is considered to be notably higher in patients with epilepsy with respect to the general population. Sudden unexpected death in epilepsy (SUDEP) is probably caused by the peri-ictal concurrence of a number of different predisposing and precipitating factors. Among these, the presence of a seizure before the fatal event is the only feature that seems to be constantly present. Different mechanisms, namely cardiac arrhythmias, respiratory dysfunctions, dysregulation of systemic or cerebral circulation have been suggested as potential physiopathological mechanisms. Moreover, clinical data seem to suggest that SUDEP could occur preferentially during sleep. In order to assess a possible relationship between sleep and SUDEP, we have analyzed studies in which sufficient information about the circumstances of deaths was available. Our analysis confirms that the relationship between sleep and SUDEP is not given by chance as the percentage of possible sleep-related SUDEP is higher than 40% in the majority of studies. We will discuss the possible longstanding and precipitating mechanisms involved in the interaction between sleep and epilepsy likely to favour SUDEP occurrence. In this perspective, possible preventive measures will be hypothesized.
The aim of this report is not to make a differential diagnosis between epileptic nocturnal seizur... more The aim of this report is not to make a differential diagnosis between epileptic nocturnal seizures and non-epileptic sleep-related movement disorders, or parasomnias. On the contrary, our goal is to emphasize the commonly shared semiological features of some epileptic seizures and parasomnias. Such similar features might be explained by the activation of the same neuronal networks (so-called 'central pattern generators' or CPG). These produce the stereotypical rhythmic motor sequences - in other words, behaviours - that are adaptive and species-specific (such as eating/alimentary, attractive/aversive, locomotor and nesting habits). CPG are located at the subcortical level (mainly in the brain stem and spinal cord) and, in humans, are under the control of the phylogenetically more recent neomammalian neocortical structures, according to a simplified Jacksonian model. Based on video-polygraphic recordings of sleep-related epileptic seizures and non-epileptic events (parasomnias), we have documented how a transient "neomammalian brain" dysfunction - whether epileptic or not - can 'release' (disinhibition?) the CPG responsible for involuntary motor behaviours. Thus, in both epileptic seizures and parasomnias, we can observe: (a) oroalimentary automatisms, bruxism and biting; (b) ambulatory behaviours, ranging from the classical bimanual-bipedal activity of 'frontal' hypermotor seizures, epileptic and non-epileptic wanderings, and somnambulism to periodic leg movements (PLM), alternating leg muscle activation (ALMA) and restless legs syndrome (RLS); and (c) various sleep-related events such as ictal fear, sleep terrors, nightmares and violent behaviour.
It is now common knowledge that the total surgical section of the corpus callosum (CC) and of the... more It is now common knowledge that the total surgical section of the corpus callosum (CC) and of the other forebrain commissures prevents interhemispheric transfer (IT) of a host of mental functions. By contrast, IT of simple sensorimotor functions, although severely delayed, is not abolished, and an important question concerns the pathways subserving this residual IT. To answer this question we assessed visuomotor IT in split-brain patients using the Poffenberger paradigm (PP), that is, a behavioral paradigm in which simple reaction time (RT) to visual stimuli presented to the hemifield ipsilateral to the responding hand is compared to stimuli presented to the contralateral hemifield, a condition requiring an IT. We tested the possibility that the residual IT is mediated by the collicular commissure interconnecting the two sides of the superior colliculus (SC). To this purpose, we used short-wavelength visual stimuli, which in neurophysiological studies in non-human primates have been shown to be undetectable by collicular neurons. We found that, in both totally and partially callosotomised patients, IT was considerably longer with S-cone input than with L-cone input or with achromatic stimuli. This was not the case in healthy participants in whom IT was not affected by color. These data clearly show that the SC plays an important role in IT of sensorimotor information in the absence of the corpus callosum.
nnnn We report two children, suffering from idiopathic partial epilepsy, who started to present, ... more nnnn We report two children, suffering from idiopathic partial epilepsy, who started to present, in the same period of time, with epileptic negative myoclonus (ENM) in one lower limb and fecal incontinence (FI). Polygraphic recordings showed that ENM was associated with paroxysmal activities distributed over the vertex region. Both ENM and FI disappeared when ethosuximide treatment was started. We hypothesize that, in our patients, ENM in one lower limb and FI depended on a transitory impairment, caused by epileptic activity that altered the functionality of nearby cortical areas, located in fronto-mesial regions, involved in the control of the muscular tone of the lower limbs and of the pelvic floor muscles.
Saccharomyces cerevisiae mutants lacking oxidative stress response genes were used to investigate... more Saccharomyces cerevisiae mutants lacking oxidative stress response genes were used to investigate which genes are required under normal aerobic conditions to maintain cellular redox homeostasis, using intracellular glutathione redox potential (glutathione E h ) to indicate the redox environment of the cells. Levels of reactive oxygen species (ROS) and mitochondrial membrane potentials (MMP) were also assessed by FACS using dihydroethidium and rhodamine 123 as fluorescent probes. Cells became more oxidised as strains shifted from exponential growth to stationary phase. During both phases the presence of reduced thioredoxin and the activity of glutathione reductase were important for redox homeostasis. Thioredoxin reductase contributed less during exponential phase when there was a strong requirement for active Yap1p transcription factor, but was critical during stationary phase. The absence of ROS detoxification systems, such as catalases or superoxide dismutases, had a lesser effect on glutathione E h , but a more pronounced effect on ROS levels and MMP. These results reflect the major shift in ROS generation as cells switch from fermentative to respiratory metabolism and also showed that there was not a strong correlation between ROS production, MMP and cellular redox environment. Heterogeneity was detected in populations of strains with compromised anti-oxidant defences, and as cells aged they shifted from one cell type with low ROS content to another with much higher intracellular ROS.
Pattern visual evoked potentials (VEPs) were recorded from the pial surface of the cat primary vi... more Pattern visual evoked potentials (VEPs) were recorded from the pial surface of the cat primary visual cortex prior to and following the intravenous administration of physostigmine, an agent which blocks the enzyme responsible for the breakdown of synaptically released acetylcholine. The control VEP was composed of a small initial positive deflection (P1), a subsequent large negative wave (N1) and a second large positive wave (P2). Following physostigmine, the amplitude of P1-N1 was diminished whereas that of N1-P2 increased. These effects were long lasting and were blocked by prior treatment with scopolamine, a result consistent with mediation by a muscarinic cholinergic pathway. Waveform subtraction revealed that the physostigmine-sensitive component had a slow, negative polarity waveform while the physostigmine-insensitive component was also slow, but positive in polarity. The fundamental nature of these components remains to be assessed. Nevertheless, the results indicate that waveforms of different polarity combine algebraically to yield the conventional VEP.
Electroencephalography and Clinical Neurophysiology/Electromyography and Motor Control, 1995
Poster session 28. Epilepsy (1) decreased tracer accumulation in ~231-1omazenil SPECT indicate de... more Poster session 28. Epilepsy (1) decreased tracer accumulation in ~231-1omazenil SPECT indicate decreased BZr binding, we speculate that decreased GABAA/BZr is related to the basic mechanism of temporal lobe epilepsy.
Epileptic disorders : international epilepsy journal with videotape, 2007
Charles Bonnet syndrome (CBS) is a disorder characterized by the occurrence of complex visual hal... more Charles Bonnet syndrome (CBS) is a disorder characterized by the occurrence of complex visual hallucinations in patients with acquired impairment of vision and without psychiatric disorders. In spite of the high incidence of visual field defects following antero-mesial temporal lobectomy for refractory temporal lobe epilepsy, reports of CBS in patients who underwent this surgical procedure are surprisingly rare. We describe a patient operated on for drug-resistant epilepsy. As a result of left antero-mesial temporal resection, she presented right homonymous hemianopia. A few days after surgery, she started complaining of visual hallucinations, such as static or moving "Lilliputian" human figures, or countryside scenes, restricted to the hemianopic field. The patient was fully aware of their fictitious nature. These disturbances disappeared progressively over a few weeks. The incidence of CBS associated with visual field defects following epilepsy surgery might be underesti...
Epileptic disorders : international epilepsy journal with videotape, 2001
We investigated the electroclinical features of 12 patients with childhood absence epilepsy (CAE)... more We investigated the electroclinical features of 12 patients with childhood absence epilepsy (CAE), presenting with typical absence seizures associated with myoclonic manifestations of the face or neck. All patients underwent repeated and prolonged split-screen video-polygraphic EEG recordings. The polygraphic recordings and clinical correlations of the absence seizures were analysed. All patients presented with multi-quotidian, typical absence seizures. During the absences, the patients could show mild, rhythmic, myoclonic jerks involving facial areas (eyebrows, nostrils, perioral region, chin) or neck muscles (sternocleidomastoideus), with the same frequency as the spike-wave complexes. Polygraphic tracings demonstrated that the myoclonias were correlated to the spike component. Clinically, all patients showed a benign course, with complete seizure control under antiepileptic treatment. In the follow-up, 7 patients withdrew from treatment without relapse. We conclude that all our p...
Epileptic disorders : international epilepsy journal with videotape, 2008
We describe the case of an eight-year-old boy, who underwent a video-stereo EEG (SEEG) investigat... more We describe the case of an eight-year-old boy, who underwent a video-stereo EEG (SEEG) investigation for the presurgical assessment of drug-resistant epilepsy, related to a right fronto-lateral cortical dysplasia and who became seizure-free after epilepsy surgery. The unexpected finding of the investigations was that intracerebral, high frequency (50 Hz) electrical stimulation (HFS) triggered the emergence of automatic and involuntary forward-backward locomotion during a focal seizure while the boy was standing. This clinical manifestation was different from the chaotic motor activity described during epileptic wanderings. The stimulation of the same fronto-lateral region, while the patient was lying, produced only the subjective sensation that the legs were moving, although there was no physical manifestation of this. Human locomotion is an innate motor behavior that is normally due to the activation of the spinal network for locomotion (central pattern generator). The emergence of...
To estimate the prevalence of nocturnal frontal lobe epilepsy (NFLE) in the adults of two areas o... more To estimate the prevalence of nocturnal frontal lobe epilepsy (NFLE) in the adults of two areas of the Emilia-Romagna region (northeast Italy) and to describe the clinical features from a population-based perspective. Population-based retrospective cohort study including adults with NFLE. Two areas of the Emilia-Romagna region: the city of Bologna (330,901 adult residents) and five districts of the province of Modena (424,007). Prevalence day: December 31, 2010. Patients with NFLE collected from multiple databases of neurologic hub centers of the districts involved. Diagnostic criteria: clinical history of sleep related bizarre motor attacks and videopolysomnographic recording confirming the typical features of NFLE. Inclusion criteria for prevalence calculation: residence in one of the two geographic areas on the prevalence day and an "active" or "in remission with treatment" form of NFLE. Six subjects from Bologna and eight from Modena were included. Crude prevalence (per 100,000 residents) was 1.8 (95% confidence interval 0.7-4.0) in Bologna and 1.9 (0.8-3.7) in Modena. Similarly, the main clinical features were consistent: onset during adolescence (median age 11-13 y), mainly hyperkinetic seizures, nonlesional form in more than two-thirds of cases, an active form of epilepsy in more than two-thirds of cases. A family history of epilepsy was reported only for two patients. This epidemiologic study establishes that NFLE is a rare epileptic condition, fulfilling the definition for rare disease. Because of methodological limitations of our case ascertainment, the estimates we disclose must be considered the minimum prevalence.
Sudden unexpected death in epilepsy Sleep Obstructive sleep apnoea Autonomic system s u m m a r y... more Sudden unexpected death in epilepsy Sleep Obstructive sleep apnoea Autonomic system s u m m a r y The risk of sudden unexpected death is considered to be notably higher in patients with epilepsy with respect to the general population. Sudden unexpected death in epilepsy (SUDEP) is probably caused by the peri-ictal concurrence of a number of different predisposing and precipitating factors. Among these, the presence of a seizure before the fatal event is the only feature that seems to be constantly present. Different mechanisms, namely cardiac arrhythmias, respiratory dysfunctions, dysregulation of systemic or cerebral circulation have been suggested as potential physiopathological mechanisms. Moreover, clinical data seem to suggest that SUDEP could occur preferentially during sleep. In order to assess a possible relationship between sleep and SUDEP, we have analyzed studies in which sufficient information about the circumstances of deaths was available. Our analysis confirms that the relationship between sleep and SUDEP is not given by chance as the percentage of possible sleep-related SUDEP is higher than 40% in the majority of studies. We will discuss the possible longstanding and precipitating mechanisms involved in the interaction between sleep and epilepsy likely to favour SUDEP occurrence. In this perspective, possible preventive measures will be hypothesized.
The aim of this report is not to make a differential diagnosis between epileptic nocturnal seizur... more The aim of this report is not to make a differential diagnosis between epileptic nocturnal seizures and non-epileptic sleep-related movement disorders, or parasomnias. On the contrary, our goal is to emphasize the commonly shared semiological features of some epileptic seizures and parasomnias. Such similar features might be explained by the activation of the same neuronal networks (so-called 'central pattern generators' or CPG). These produce the stereotypical rhythmic motor sequences - in other words, behaviours - that are adaptive and species-specific (such as eating/alimentary, attractive/aversive, locomotor and nesting habits). CPG are located at the subcortical level (mainly in the brain stem and spinal cord) and, in humans, are under the control of the phylogenetically more recent neomammalian neocortical structures, according to a simplified Jacksonian model. Based on video-polygraphic recordings of sleep-related epileptic seizures and non-epileptic events (parasomnias), we have documented how a transient "neomammalian brain" dysfunction - whether epileptic or not - can 'release' (disinhibition?) the CPG responsible for involuntary motor behaviours. Thus, in both epileptic seizures and parasomnias, we can observe: (a) oroalimentary automatisms, bruxism and biting; (b) ambulatory behaviours, ranging from the classical bimanual-bipedal activity of 'frontal' hypermotor seizures, epileptic and non-epileptic wanderings, and somnambulism to periodic leg movements (PLM), alternating leg muscle activation (ALMA) and restless legs syndrome (RLS); and (c) various sleep-related events such as ictal fear, sleep terrors, nightmares and violent behaviour.
It is now common knowledge that the total surgical section of the corpus callosum (CC) and of the... more It is now common knowledge that the total surgical section of the corpus callosum (CC) and of the other forebrain commissures prevents interhemispheric transfer (IT) of a host of mental functions. By contrast, IT of simple sensorimotor functions, although severely delayed, is not abolished, and an important question concerns the pathways subserving this residual IT. To answer this question we assessed visuomotor IT in split-brain patients using the Poffenberger paradigm (PP), that is, a behavioral paradigm in which simple reaction time (RT) to visual stimuli presented to the hemifield ipsilateral to the responding hand is compared to stimuli presented to the contralateral hemifield, a condition requiring an IT. We tested the possibility that the residual IT is mediated by the collicular commissure interconnecting the two sides of the superior colliculus (SC). To this purpose, we used short-wavelength visual stimuli, which in neurophysiological studies in non-human primates have been shown to be undetectable by collicular neurons. We found that, in both totally and partially callosotomised patients, IT was considerably longer with S-cone input than with L-cone input or with achromatic stimuli. This was not the case in healthy participants in whom IT was not affected by color. These data clearly show that the SC plays an important role in IT of sensorimotor information in the absence of the corpus callosum.
nnnn We report two children, suffering from idiopathic partial epilepsy, who started to present, ... more nnnn We report two children, suffering from idiopathic partial epilepsy, who started to present, in the same period of time, with epileptic negative myoclonus (ENM) in one lower limb and fecal incontinence (FI). Polygraphic recordings showed that ENM was associated with paroxysmal activities distributed over the vertex region. Both ENM and FI disappeared when ethosuximide treatment was started. We hypothesize that, in our patients, ENM in one lower limb and FI depended on a transitory impairment, caused by epileptic activity that altered the functionality of nearby cortical areas, located in fronto-mesial regions, involved in the control of the muscular tone of the lower limbs and of the pelvic floor muscles.
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Papers by G. Rubboli