The Experts below are selected from a list of 162 Experts worldwide ranked by ideXlab platform
Giovanna Zoccoli - One of the best experts on this subject based on the ideXlab platform.
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High-amplitude theta wave bursts characterizing narcoleptic mice and patients are also produced by histamine deficiency in mice.
Journal of sleep research, 2016Co-Authors: Stefano Bastianini, Viviana Lo Martire, Chiara Berteotti, Alessandro Silvani, Hiroshi Ohtsu, Jian-sheng Lin, Giovanna ZoccoliAbstract:Histamine and orexins are wake promoters released by hypothalamic neurons. The activity of histamine neurons is increased by orexin neurons. Recently, it has been shown that orexin deficiency entails high-amplitude theta wave bursts during rapid eye movement sleep and cataplexy in narcoleptic mice. The primary aim of this study was to assess whether histamine system is involved in high-amplitude theta wave burst generation during rapid eye movement sleep. The secondary aim was to assess the effects of combined histamine and orexin deficiency on high-amplitude theta wave bursts during rapid eye movement sleep in mice. Twelve histidine-decarboxylase knockout mice with congenital histamine deficiency, seven double mutant mice with combined deficiency of orexin neurons and histamine, and 11 wild-type control mice were studied with electrodes for sleep recordings and a telemetric Blood Pressure Transducer. High-amplitude theta wave bursts during rapid eye movement sleep were detected in each of the histidine-decarboxylase knockout and double mutant mice, whereas only one burst was found in a wild-type control mouse. High-amplitude theta wave bursts occurred significantly more often and were significantly longer in double mutant than in histidine-decarboxylase knockout mice. In conclusion, it was demonstrated that, similarly to orexin, the chronic impairment of histamine entailed high-amplitude theta wave bursts during rapid eye movement sleep. The current data also suggested a synergistic role of orexin and histamine signalling on high-amplitude theta wave bursts during rapid eye movement sleep in mice.
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Effects of Ambient Temperature on Sleep and Cardiovascular Regulation in Mice: The Role of Hypocretin/Orexin Neurons
PloS one, 2012Co-Authors: Viviana Lo Martire, Stefano Bastianini, Chiara Berteotti, Alessandro Silvani, Giovanna ZoccoliAbstract:The central neural pathways underlying the physiological coordination between thermoregulation and the controls of the wake-sleep behavior and cardiovascular function remain insufficiently understood. Growing evidence supports the involvement of hypocretin (orexin) peptides in behavioral, cardiovascular, and thermoregulatory functions. We investigated whether the effects of ambient temperature on wake-sleep behavior and cardiovascular control depend on the hypothalamic neurons that release hypocretin peptides. Orexin-ataxin3 transgenic mice with genetic ablation of hypocretin neurons (n = 11) and wild-type controls (n = 12) were instrumented with electrodes for sleep scoring and a telemetric Blood Pressure Transducer. Simultaneous sleep and Blood Pressure recordings were performed on freely-behaving mice at ambient temperatures ranging between mild cold (20°C) and the thermoneutral zone (30°C). In both mouse groups, the time spent awake and Blood Pressure were higher at 20°C than at 30°C. The cold-related increase in Blood Pressure was significantly smaller in rapid-eye-movement sleep (REMS) than either in non-rapid-eye-movement sleep (NREMS) or wakefulness. Blood Pressure was higher in wakefulness than either in NREMS or REMS at both ambient temperatures. This effect was significantly blunted in orexin-ataxin3 mice irrespective of ambient temperature and particularly during REMS. These data demonstrate that hypocretin neurons are not a necessary part of the central pathways that coordinate thermoregulation with wake-sleep behavior and cardiovascular control. Data also support the hypothesis that hypocretin neurons modulate changes in Blood Pressure between wakefulness and the sleep states. These concepts may have clinical implications in patients with narcolepsy with cataplexy, who lack hypocretin neurons.
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Control of cardiovascular variability during undisturbed wake-sleep behavior in hypocretin-deficient mice.
American journal of physiology. Regulatory integrative and comparative physiology, 2012Co-Authors: Alessandro Silvani, Stefano Bastianini, Chiara Berteotti, Viviana Lo Martire, Giovanna ZoccoliAbstract:The central neural mechanisms underlying differences in cardiovascular variability between wakefulness, non-rapid-eye-movement sleep (NREMS), and rapid-eye-movement sleep (REMS) remain poorly understood. These mechanisms may involve hypocretin (HCRT)/orexin signaling. HCRT signaling is linked to wake-sleep states, involved in central autonomic control, and impaired in narcoleptic patients. Thus, we investigated whether HCRT signaling plays a role in controlling cardiovascular variability during spontaneous behavior in HCRT-deficient mice. HCRT-ataxin3 transgenic mice lacking HCRT neurons (TG), knockout mice lacking HCRT peptides (KO), and wild-type controls (WT) were instrumented with electrodes for sleep recordings and a telemetric Blood Pressure Transducer. Fluctuations of systolic Blood Pressure (SBP) and heart period (HP) during undisturbed wake-sleep behavior were analyzed with the sequence technique, cross-correlation functions, and coherent averaging of SBP surges. During NREMS, all mice had lower SBP variability, greater baroreflex contribution to HP control at low frequencies, and greater amplitude of the central autonomic and baroreflex changes in HP associated with SBP surges than during wakefulness. During REMS, all mice had higher SBP variability and depressed central autonomic and baroreflex HP controls relative to NREMS. HP variability during REMS was higher than during NREMS in WT only. TG and KO also had lower amplitude of the cardiac baroreflex response to SBP surges during REMS than WT. These results indicate that chronic lack of HCRT signaling may cause subtle alterations in the control of HP during spontaneous behavior. Conversely, the integrity of HCRT signaling is not necessary for the occurrence of physiological sleep-dependent changes in SBP variability.
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High-amplitude theta wave bursts during REM sleep and cataplexy in hypocretin-deficient narcoleptic mice.
Journal of sleep research, 2011Co-Authors: Stefano Bastianini, Viviana Lo Martire, Chiara Berteotti, Alessandro Silvani, Giovanna ZoccoliAbstract:SUMMARY Neurons that release hypocretin (HCRT; orexin) peptides control wake‐ sleep states and autonomic functions, and are lost in patients with narcolepsy with cataplexy. Bursts of high-amplitude electroencephalographic (EEG) activity have been reported during behavioural arrests and rapid eye movement sleep (REMS) episodes at sleep onset in HCRTdeficient narcoleptic mice. Quantitative information on these EEG phenomena is lacking. We aimed to quantify EEG frequency, occurrence rate, daily rhythm and cardiovascular correlates of high-amplitude EEG bursts during REMS and cataplexy. Twenty HCRT-deficient mice and 15 congenic wild-type controls were instrumented with electrodes for sleep recordings and a telemetric Blood Pressure Transducer. Short (1‐2 s) high-amplitude bursts of pointed theta waves (7 Hz) occurred during either REMS or cataplexy in 80% of HCRT-deficient mice without any significant accompanying modification in systolic Blood Pressure or heart period. Theta bursts were significantly more likely to occur during the dark period and in the last third of REMS episodes. Similar EEG events were detected in a significantly lower fraction (27%) of wild-type mice and with a significantly lower occurrence rate (0.8 versus 5 per hour of REMS). These data demonstrate that occurrence of high-amplitude theta bursts is facilitated during REMS and cataplexy in narcoleptic mice. Analysis of EEG frequency and daily and intra-episode patterns of event occurrence do not support interpretation of theta bursts as temporally displaced pre-REMS spindles. Facilitation of high-amplitude theta bursts may thus represent a novel neurophysiological abnormality associated with chronic HCRT deficiency.
Miguel A. Teus - One of the best experts on this subject based on the ideXlab platform.
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Porcine Model to Evaluate Real-Time Intraocular Pressure During Femtosecond Laser Cataract Surgery.
Current eye research, 2015Co-Authors: Marta Ibarz, José Luis Hernández-verdejo, Gema Bolívar, Pedro Tañá, José Luis Rodríguez-prats, Miguel A. TeusAbstract:AbstractPurpose: To investigate the changes in intraocular Pressure (IOP) in porcine eyes during femtosecond laser-assisted cataract surgery using a liquid-optic interface system.Materials and methods: Femtosecond laser cataract surgery with the Catalys™ was performed on freshly enucleated porcine eyes in Oftalvist Moncloa, Madrid, Spain. Capsulorhexis and lens fragmentation were completed in all the eyes without complications. IOP was measured with a reusable Blood Pressure Transducer connected by direct cannulation to the anterior chamber, recording data before suction (basal), at the beginning of the suction phase, every five seconds during femtosecond procedure and after the removal of the suction ring from the eye.Results: Nine porcine eyes were used in this study. Basal IOP before suction was 5.67 ± 2.39 mmHg, rising to 20.33 ± 4.18 mmHg at the beginning of the suction phase (p
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comparison of real time intraocular Pressure during laser in situ keratomileusis and epithelial laser in situ keratomileusis in porcine eyes
Journal of Cataract and Refractive Surgery, 2010Co-Authors: Jose Luis Hernandezverdejo, Laura De Benitollopis, Miguel A. TeusAbstract:Purpose To compare real-time intraocular Pressure (IOP) between laser in situ keratomileusis (LASIK) and epithelial LASIK (epi-LASIK) in porcine eyes during flap creation using a microkeratome or an epikeratome, respectively. Setting Vissum Madrid, Madrid, Spain. Methods In this prospective study, a Moria microkeratome was used in 1 eye (LASIK group) and an Epi-K epikeratome in the other eye (epi-LASIK group) to create a lamellar corneal flap and an epithelial flap, respectively, in freshly enucleated porcine eyes. The IOP changes during the procedures were recorded by direct cannulation using a reusable Blood Pressure Transducer connected to the anterior chamber. Results Each group comprised 17 eyes. In the LASIK group, the mean IOP was 113.65 mm Hg ± 10.78 (SD) during suctioning and 112.35 ± 11.51 mm Hg during cutting phases. The mean duration of the phases was 9.00 ± 1.46 seconds and 6.06 ± 1.14 seconds, respectively. In the epi-LASIK group, the mean IOP was 92.57 ± 20.86 mm Hg during suctioning, 82.09 ± 20 mm Hg during cutting, and 67.28 ± 13.49 during low vacuum. The mean duration of the phases was 25.88 ± 1.96 seconds, 33.82 ± 2.81 seconds, and 29.71 ± 3.29 seconds, respectively. The IOP values were significantly different between the 2 groups (all comparisons P Conclusion Real-time IOP measured during suctioning and flap creation by direct cannulation of the anterior chamber in freshly enucleated porcine eyes showed a significant increase in IOP during LASIK and epi-LASIK; the increase was lower in the epi-LASIK group. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.
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Comparison of real intraocular Pressure (IOP) during LASIK versus Epi-LASIK
Acta Ophthalmologica, 2008Co-Authors: P Canadas Suarez, J.l. Hernández Verdejo, L De Benito, Miguel A. TeusAbstract:Purpose To compare real-time intraocular Pressure (IOP) in LASIK versus Epi-LASIK in porcine eyes during flap creation using the Moria 2 microkeratome and the Moria Epi-KTM epikeratome. Methods Interventional, prospective study of two keratomes: Moria Group (M2) and epipolis laser in situ keratomileusis Group (MEpi-K). These devices were used to create a lamellar corneal or epithelial flap respectively in freshly enucleated porcine eyes. The IOP changes induced by the procedures were recorded using manometry by direct cannulation with a reusable Blood Pressure Transducer connected to the anterior chamber. Results 7 eyes were included for M2 Group and 10 for the MEpi-K Group. In the M2 Group the IOP increased during suction phase to a mean value of 122.53±30.40 mm Hg and to 160.52±22.73 mm Hg during cutting phase (mean time: 21.42±7.48 and 15.71±1.88 secs respectively). In the MEpi-K Group, mean IOP increase was 100.66±18.60 mm Hg during suction phase, 91.38±17.79 mm Hg during cutting phase and 74,37±12.70 during low-back phase (mean time: 25.79±3.44, 33.68±2.81 and 29.74± 3.11 secs respectively). IOP values in both groups showed statistical significant difference in all comparison (p
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Porcine Model to Compare Real-Time Intraocular Pressure during LASIK with a Mechanical Microkeratome and Femtosecond Laser
Investigative ophthalmology & visual science, 2007Co-Authors: José Luis Hernández-verdejo, Miguel A. Teus, José M. Román, Gema BolívarAbstract:PURPOSE To compare real-time intraocular Pressure (IOP) during laser in situ keratomileusis (LASIK) in porcine eyes using two types of microkeratomes. METHODS An interventional, prospective study of two microkeratomes: a Moria 2 (Moria group) and an IntraLase femtosecond laser (IntraLase Corp., Irvine, CA; IntraLase group). These devices were used to create lamellar corneal flaps in freshly enucleated porcine eyes. The IOP changes induced by the procedures were recorded with a reusable Blood Pressure Transducer connected to the anterior chamber by direct cannulation. RESULTS Seven porcine eyes were studied in each group. The IOP increased during the suctioning phase, reaching a mean of 122.52 +/- 30.40 and 160.52 +/- 22.73 mm Hg during the cutting phase in the Moria group (the total time in this group was 36.42 +/- 7.48 seconds; suctioning required 21.42 +/- 7.48 seconds and the cutting phase, 15 +/- 2.88 seconds). In the IntraLase group, the IOP reached 89.24 +/- 24.26 mm Hg during the suctioning phase and 119.33 +/- 15.88 mm Hg during the intrastromal laser application (the total time was 92.85 +/- 13.49 seconds; suctioning required 40.00 +/- 9.57 seconds and the cutting phase 52.85 +/- 5.66 seconds). Both IOPs during both phases differed significantly between the two groups (P = 0.01 for all comparisons). CONCLUSIONS Real-time IOP can be measured during LASIK using a Transducer connected to the anterior chamber. The results showed a significant increase in IOP during the procedure in both groups, although with the IntraLase the IOP seemed to increase to a lesser extent than with the conventional mechanical microkeratome.
Ana D. O. Paixão - One of the best experts on this subject based on the ideXlab platform.
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Fetal development and renal function in adult rats prenatally subjected to sodium overload
Pediatric Nephrology, 2009Co-Authors: Henriqueta D. Cardoso, Edjair V. Cabral, Leucio D. Vieira-filho, Adalberto Vieyra, Ana D. O. PaixãoAbstract:The aims of this study were (1) to evaluate two factors that affect fetal development—placental oxidative stress (Ox) and plasma volume (PV)—in dams with sodium overload and (2) to correlate possible alterations in these factors with subsequent modifications in the renal function of adult offspring. Wistar dams were maintained on 0.17 M NaCl instead of water from 20 days before mating until either the twentieth pregnancy day/parturition or weaning. Colorimetric methods were used to measure Ox in maternal and offspring tissues, PV, 24-h urinary protein (U_Prot24 h) and serum triacylglycerols (TG) and cholesterol (Chol). Renal hemodynamics was evaluated in the offspring at 90 days of age using a Blood Pressure Transducer, a flow probe and inulin clearance to measure mean arterial Pressure (MAP), renal Blood flow and glomerular filtration rate (GFR), respectively. The number of nephrons (NN) was counted in kidney suspensions. Dams showed unchanged PV, placental Ox and fetal weight but increased U_Prot24 h (150%, P
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Fetal development and renal function in adult rats prenatally subjected to sodium overload.
Pediatric nephrology (Berlin Germany), 2009Co-Authors: Henriqueta D. Cardoso, Edjair V. Cabral, Leucio D. Vieira-filho, Adalberto Vieyra, Ana D. O. PaixãoAbstract:The aims of this study were (1) to evaluate two factors that affect fetal development—placental oxidative stress (Ox) and plasma volume (PV)—in dams with sodium overload and (2) to correlate possible alterations in these factors with subsequent modifications in the renal function of adult offspring. Wistar dams were maintained on 0.17 M NaCl instead of water from 20 days before mating until either the twentieth pregnancy day/parturition or weaning. Colorimetric methods were used to measure Ox in maternal and offspring tissues, PV, 24-h urinary protein (UProt24 h) and serum triacylglycerols (TG) and cholesterol (Chol). Renal hemodynamics was evaluated in the offspring at 90 days of age using a Blood Pressure Transducer, a flow probe and inulin clearance to measure mean arterial Pressure (MAP), renal Blood flow and glomerular filtration rate (GFR), respectively. The number of nephrons (NN) was counted in kidney suspensions. Dams showed unchanged PV, placental Ox and fetal weight but increased UProt24 h (150%, P < 0.05). Prenatally sodium-overloaded pups showed increased UProt24 h (45%, P < 0.05) but unchanged MAP, renal hemodynamics, NN and kidney Ox. Prenatally and postnatally sodium-overloaded rats showed increased UProt24 h (27%, P < 0.05) and kidney Ox (44%, P < 0.05), reduced GFR (12%, P < 0.05), increased PV (26%, P < 0.05) and unchanged MAP and NN. The TG increased in both groups of treated offspring (21%, P < 0.05), whereas Chol increased only in the postnatally sodium-overloaded group. We conclude that salt overload from the prenatal stage until weaning leads to alterations in lipid metabolism and in the renal function of the pups, which are additional to those alterations seen in rats only overloaded prenatally.
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Repercussion of acetylsalicylic acid during fetal development on later renal hemodynamics of rats
Fundamental & clinical pharmacology, 2008Co-Authors: Leucio D. Vieira-filho, José M. Lucena‐júnior, Izabel S.s. Barreto, José L.c. Angelim, Ana D. O. PaixãoAbstract:Acetylsalicylic acid (ASA) during pregnancy reaches the fetus. It seems important to know possible repercussions of ASA on later renal function of the offspring, as well as repercussions of this drug on factors that may influence fetal development, such as maternal plasma volume and placental oxidative stress. It was evaluated whether ASA changes maternal plasma volume and/or placental oxidative stress, fetal weight and renal function of the offspring at adult life. ASA (100 mg/kg/day, p.o., dissolved in ETOH 10%) or ETOH 10% was administered to Wistar rat dams, from the day 7 to day 20 of pregnancy/parturition. Plasma volume and the placental oxidative stress were evaluated on day 20 of pregnancy, using, respectively, the Evans blue dye and the thiobarbituric acid reactive substances methods. Mean arterial Pressure, renal Blood flow (RBF) and glomerular filtration rate (GFR) were evaluated in the anesthetized offspring, at the age of 90 days, using a Blood Pressure Transducer, a flow probe and inulin clearance respectively. Plasma volume was 76% (P < 0.05) higher in ASA compared with that in control dams, but placental oxidative stress was the same for both groups. Fetal body weight, the number of nephrons, GFR, RBF and renal vascular resistance were similar for the same gender among the offspring of the two groups. However, reduced hematocrit (9.8%, P < 0.05), increased renal plasma flow (27%, P < 0.05) and reduced filtration fraction (32%, P < 0.05) were seen in the female offspring. In conclusion, although ASA had increased maternal plasma volume, it did not change nephrogenesis nor GFR in the adult offspring. The changes in renal plasma flow and filtration fraction seen in the ASA female offspring might partially be due to the reduced hematocrit.
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Renal function in adult rats subjected to prenatal dexamethasone.
Clinical and experimental pharmacology & physiology, 2003Co-Authors: João P.c. Martins, Josélia C. Monteiro, Ana D. O. PaixãoAbstract:Summary 1. Prenatal dexamethasone leads to low birth weight and compromises organogenesis, but its effects on nephrogenesis in male and female rats have not yet been investigated extensively. Reduced renal mass may be responsible for hypertension and renal haemodynamic and morphological adjustments to maintain the glomerular filtration rate (GFR). Subsequently, these compensatory mechanisms determine glomerular sclerosis and irreversible reduction in GFR. When a high-protein diet is associated with reduced renal mass, it accelerates glomerular sclerosis and the decline in renal function. The aim of the present study was to evaluate whether rats subjected to prenatal dexamethasone and a high-protein diet during growth present a premature decline in renal function. 2. The number of nephrons and renal haemodynamics were estimated in Wistar rats fed a high-protein diet (40% protein) after weaning in offspring of dams treated with either dexamethasone (0.1 mg/kg per day) or its vehicle (control; physiological solution, 0.1 mL/kg per day) during gestation. 3. At 70 days of age, rat offspring were anaesthetized and prepared surgically for renal haemodynamic measurements. 4. Mean arterial Pressure (MAP), renal Blood flow (RBF) and GFR were measured using a Blood Pressure Transducer, a flow probe and inulin clearance, respectively. 5. The number of nephrons was counted using the acid-maceration technique. 6. Dexamethasone during pregnancy induced a lower weight gain in the dams (65%; P
Stefano Bastianini - One of the best experts on this subject based on the ideXlab platform.
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High-amplitude theta wave bursts characterizing narcoleptic mice and patients are also produced by histamine deficiency in mice.
Journal of sleep research, 2016Co-Authors: Stefano Bastianini, Viviana Lo Martire, Chiara Berteotti, Alessandro Silvani, Hiroshi Ohtsu, Jian-sheng Lin, Giovanna ZoccoliAbstract:Histamine and orexins are wake promoters released by hypothalamic neurons. The activity of histamine neurons is increased by orexin neurons. Recently, it has been shown that orexin deficiency entails high-amplitude theta wave bursts during rapid eye movement sleep and cataplexy in narcoleptic mice. The primary aim of this study was to assess whether histamine system is involved in high-amplitude theta wave burst generation during rapid eye movement sleep. The secondary aim was to assess the effects of combined histamine and orexin deficiency on high-amplitude theta wave bursts during rapid eye movement sleep in mice. Twelve histidine-decarboxylase knockout mice with congenital histamine deficiency, seven double mutant mice with combined deficiency of orexin neurons and histamine, and 11 wild-type control mice were studied with electrodes for sleep recordings and a telemetric Blood Pressure Transducer. High-amplitude theta wave bursts during rapid eye movement sleep were detected in each of the histidine-decarboxylase knockout and double mutant mice, whereas only one burst was found in a wild-type control mouse. High-amplitude theta wave bursts occurred significantly more often and were significantly longer in double mutant than in histidine-decarboxylase knockout mice. In conclusion, it was demonstrated that, similarly to orexin, the chronic impairment of histamine entailed high-amplitude theta wave bursts during rapid eye movement sleep. The current data also suggested a synergistic role of orexin and histamine signalling on high-amplitude theta wave bursts during rapid eye movement sleep in mice.
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Effects of Ambient Temperature on Sleep and Cardiovascular Regulation in Mice: The Role of Hypocretin/Orexin Neurons
PloS one, 2012Co-Authors: Viviana Lo Martire, Stefano Bastianini, Chiara Berteotti, Alessandro Silvani, Giovanna ZoccoliAbstract:The central neural pathways underlying the physiological coordination between thermoregulation and the controls of the wake-sleep behavior and cardiovascular function remain insufficiently understood. Growing evidence supports the involvement of hypocretin (orexin) peptides in behavioral, cardiovascular, and thermoregulatory functions. We investigated whether the effects of ambient temperature on wake-sleep behavior and cardiovascular control depend on the hypothalamic neurons that release hypocretin peptides. Orexin-ataxin3 transgenic mice with genetic ablation of hypocretin neurons (n = 11) and wild-type controls (n = 12) were instrumented with electrodes for sleep scoring and a telemetric Blood Pressure Transducer. Simultaneous sleep and Blood Pressure recordings were performed on freely-behaving mice at ambient temperatures ranging between mild cold (20°C) and the thermoneutral zone (30°C). In both mouse groups, the time spent awake and Blood Pressure were higher at 20°C than at 30°C. The cold-related increase in Blood Pressure was significantly smaller in rapid-eye-movement sleep (REMS) than either in non-rapid-eye-movement sleep (NREMS) or wakefulness. Blood Pressure was higher in wakefulness than either in NREMS or REMS at both ambient temperatures. This effect was significantly blunted in orexin-ataxin3 mice irrespective of ambient temperature and particularly during REMS. These data demonstrate that hypocretin neurons are not a necessary part of the central pathways that coordinate thermoregulation with wake-sleep behavior and cardiovascular control. Data also support the hypothesis that hypocretin neurons modulate changes in Blood Pressure between wakefulness and the sleep states. These concepts may have clinical implications in patients with narcolepsy with cataplexy, who lack hypocretin neurons.
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Control of cardiovascular variability during undisturbed wake-sleep behavior in hypocretin-deficient mice.
American journal of physiology. Regulatory integrative and comparative physiology, 2012Co-Authors: Alessandro Silvani, Stefano Bastianini, Chiara Berteotti, Viviana Lo Martire, Giovanna ZoccoliAbstract:The central neural mechanisms underlying differences in cardiovascular variability between wakefulness, non-rapid-eye-movement sleep (NREMS), and rapid-eye-movement sleep (REMS) remain poorly understood. These mechanisms may involve hypocretin (HCRT)/orexin signaling. HCRT signaling is linked to wake-sleep states, involved in central autonomic control, and impaired in narcoleptic patients. Thus, we investigated whether HCRT signaling plays a role in controlling cardiovascular variability during spontaneous behavior in HCRT-deficient mice. HCRT-ataxin3 transgenic mice lacking HCRT neurons (TG), knockout mice lacking HCRT peptides (KO), and wild-type controls (WT) were instrumented with electrodes for sleep recordings and a telemetric Blood Pressure Transducer. Fluctuations of systolic Blood Pressure (SBP) and heart period (HP) during undisturbed wake-sleep behavior were analyzed with the sequence technique, cross-correlation functions, and coherent averaging of SBP surges. During NREMS, all mice had lower SBP variability, greater baroreflex contribution to HP control at low frequencies, and greater amplitude of the central autonomic and baroreflex changes in HP associated with SBP surges than during wakefulness. During REMS, all mice had higher SBP variability and depressed central autonomic and baroreflex HP controls relative to NREMS. HP variability during REMS was higher than during NREMS in WT only. TG and KO also had lower amplitude of the cardiac baroreflex response to SBP surges during REMS than WT. These results indicate that chronic lack of HCRT signaling may cause subtle alterations in the control of HP during spontaneous behavior. Conversely, the integrity of HCRT signaling is not necessary for the occurrence of physiological sleep-dependent changes in SBP variability.
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High-amplitude theta wave bursts during REM sleep and cataplexy in hypocretin-deficient narcoleptic mice.
Journal of sleep research, 2011Co-Authors: Stefano Bastianini, Viviana Lo Martire, Chiara Berteotti, Alessandro Silvani, Giovanna ZoccoliAbstract:SUMMARY Neurons that release hypocretin (HCRT; orexin) peptides control wake‐ sleep states and autonomic functions, and are lost in patients with narcolepsy with cataplexy. Bursts of high-amplitude electroencephalographic (EEG) activity have been reported during behavioural arrests and rapid eye movement sleep (REMS) episodes at sleep onset in HCRTdeficient narcoleptic mice. Quantitative information on these EEG phenomena is lacking. We aimed to quantify EEG frequency, occurrence rate, daily rhythm and cardiovascular correlates of high-amplitude EEG bursts during REMS and cataplexy. Twenty HCRT-deficient mice and 15 congenic wild-type controls were instrumented with electrodes for sleep recordings and a telemetric Blood Pressure Transducer. Short (1‐2 s) high-amplitude bursts of pointed theta waves (7 Hz) occurred during either REMS or cataplexy in 80% of HCRT-deficient mice without any significant accompanying modification in systolic Blood Pressure or heart period. Theta bursts were significantly more likely to occur during the dark period and in the last third of REMS episodes. Similar EEG events were detected in a significantly lower fraction (27%) of wild-type mice and with a significantly lower occurrence rate (0.8 versus 5 per hour of REMS). These data demonstrate that occurrence of high-amplitude theta bursts is facilitated during REMS and cataplexy in narcoleptic mice. Analysis of EEG frequency and daily and intra-episode patterns of event occurrence do not support interpretation of theta bursts as temporally displaced pre-REMS spindles. Facilitation of high-amplitude theta bursts may thus represent a novel neurophysiological abnormality associated with chronic HCRT deficiency.
Izumi Toyoguchi - One of the best experts on this subject based on the ideXlab platform.
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Influence of the marvelous™ three-way stopcock on the natural frequency and damping coefficient in Blood Pressure Transducer kits
Journal of Clinical Monitoring and Computing, 2018Co-Authors: Shigeki Joseph Luke Fujiwara, Keiichi Tachihara, Satoshi Mori, Kentaro Ouchi, Shoko Itakura, Michiko Yasuda, Takashi Hitosugi, Uno Imaizumi, Yoichiro Miki, Izumi ToyoguchiAbstract:Two types of Planecta™ ports are commonly used as sampling ports in Blood Pressure Transducer kits: a flat-type port (FTP) and a port with a three-way stopcock (PTS). Recently, a new type of three-way stopcock (Marvelous™) has been released as a Planecta™ counterpart, but its effects on the frequency characteristics and reliability of Blood Pressure monitoring have not been investigated. We assessed the influence of the Marvelous™ stopcock on the frequency characteristics of the Pressure Transducer kit. The basic Pressure Transducer kit, DT4812J, was modified by replacing one or two of the original three-way stopcocks with Marvelous™ stopcocks. The frequency characteristics (i.e., natural frequency and damping coefficient) of each kit were determined using wave parameter analysis software, and subsequently evaluated on a Gardner chart. Replacement of the original Blood Pressure Transducer kit stopcocks with Marvelous™ stopcocks decreased the natural frequency (48.3 Hz) to 46.3 Hz or 44.8 Hz, respectively; the damping coefficient was not significantly changed. Plotting the data on a Gardner chart revealed that the changes fell within the adequate dynamic response region, indicating they were within the allowable range. Insertion of Marvelous™ stopcocks slightly affects the natural frequency of the Pressure Transducer kit, similar to inserting a PTS. The results indicate that the Marvelous™ stopcock is useful for accurate monitoring of arterial Blood Pressure, and may be recommended when insertion of two or more closed-loop Blood sampling systems is necessary.
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Effect of planecta and ROSE™ on the frequency characteristics of Blood Pressure-Transducer kits
Journal of Clinical Monitoring and Computing, 2015Co-Authors: Shigeki Fujiwara, Keiichi Tachihara, Satoshi Mori, Izumi Toyoguchi, Yoshifumi Kawakubo, Takeshi YokoyamaAbstract:Pressure-Transducer kits have frequency characteristics such as natural frequency and damping coefficient, which affect the monitoring accuracy. The aim of the present study was to investigate the effect of planecta ports and a damping device (ROSE™, Argon Medical Devices, TX, USA) on the frequency characteristics of Pressure-Transducer kits. The FloTrac sensor kit (Edwards Lifesciences, CA, USA) and the DTXplus Transducer kit (Argon Medical Devices) were prepared with planecta ports, and their frequency characteristics were tested with or without ROSE™. The natural frequency and damping coefficient of each kit were obtained using frequency characteristics analysis software and evaluated by plotting them on the Gardner’s chart. By inserting a planecta port, the natural frequency markedly decreased in both the FloTrac sensor kit (from 40 to 22 Hz) and the DTXplus Transducer kit (from 35 to 22 Hz). In both kits with one planecta port, the damping coefficient markedly increased by insertion of ROSE™ from 0.2 to 0.5, optimising frequency characteristics. In both kits with two planecta ports, however, the natural frequency decreased from 22 to 12 Hz. The damping coefficient increased from 0.2 to 0.8 by insertion of ROSE™; however, optimisation was not achieved even by ROSE™ insertion. Planecta ports decrease the natural frequency of the kit. ROSE™ is useful to optimise the frequency characteristics in the kits without or with one planecta port. However, optimisation is difficult with two or more planecta ports, even with the ROSE™ device.
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Effect of using a Planecta™ port with a three-way stopcock on the natural frequency of Blood Pressure Transducer kits
Journal of clinical monitoring and computing, 2015Co-Authors: Shigeki Fujiwara, Keiichi Tachihara, Satoshi Mori, Kentaro Ouchi, Uno Imaizumi, Yoichiro Miki, Izumi Toyoguchi, Chizuko Yokoe, Yoshinari Morimoto, Kazu Ichi YoshidaAbstract:Blood Pressure Transducer kits are equipped with two types of Planecta™ ports-the flat-type Planecta™ port (FTP) and the Planecta™ port with a three-way stopcock (PTS). We reported that FTP application decreased the natural frequency of the kits. However, Planecta™ is an invaluable tool as it prevents infection, ensures technical simplicity, and excludes air. Hence, an ideal Planecta™ port that does not decrease the frequency characteristics is required. As a first step in this direction, we aimed to assess the influence of PTSs on the natural frequency of Blood Transducer kits. A DTXplus Transducer kit (DT4812J; Argon Medical Devices, TX, USA) was used along with ≥1 PTSs (JMS, Hiroshima, Japan), and the frequency characteristics were assessed. The natural frequency and damping coefficient of each kit were obtained by using frequency characteristics analysis software, and these parameters were evaluated by plotting them on Gardner's chart. Regardless of whether one or two PTSs were inserted, the natural frequency of the kits only slightly decreased (from 42.5 to 41.1 Hz, when 2 PTSs were used). Thus, the frequency characteristics of the kits with PTSs were adequate for Pressure monitoring. The insertion of ≥2 FTPs in Pressure Transducer kits should be avoided, as they markedly decrease the natural frequency and lead to underdamping. However, the effect of PTS insertion in Pressure Transducer kits on the frequency characteristics is minimal. Thus, we found that the use of PTS markedly improved the frequency characteristics as compared to the use of FTP.