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1.
Article in English | MEDLINE | ID: mdl-38777561

ABSTRACT

OBJECTIVES: To investigate prognosis and clinical practices of infants born at 22-23 weeks' gestational age (wkGA) in Japan. DESIGN: A national institutional-level electronic questionnaire surveys performed in September 2021. SETTING: All perinatal centres across Japan. PATIENTS: Infants born at 22-23 wkGA in 2018-2020. MAIN OUTCOME MEASURES: Proportion of active resuscitation and survival at neonatal intensive care unit (NICU) discharge, and various clinical practices. RESULTS: In total, 255 of 295 NICUs (86%) responded. Among them, 145 took care of infants born at 22-23 wkGA and answered the questions regarding their outcomes and care. In most NICUs (129 of 145 (89%)), infants born at 22+0 wkGA can be actively resuscitated. In almost half of the NICUs (79 of 145 (54%)), infants born at ≥22+0 wkGA were always actively resuscitated. Among 341 and 757 infants born alive at 22 and 23 wkGA, respectively, 85% (291 of 341) and 98% (745 of 757) received active resuscitation after birth. Among infants actively resuscitated at birth, 63% (183 of 291) and 80% (594 of 745) of infants born at 22 and 23 wkGA survived, respectively. The survey revealed unique clinical management for these infants in Japan, including delivery with caul in caesarean section, cut-cord milking after clamping cord, immediate intubation at birth, hydrocortisone use for chronic lung disease, analgesia/sedation use for infants on mechanical ventilation, routine echocardiography and brain ultrasound, probiotics administration, routine glycerin enema and skin dressing to prevent pressure ulcers. CONCLUSIONS: Many 22-23 wkGA infants were actively resuscitated in Japan and had a high survival rate. Various unique clinical practices were highlighted.

2.
Surg Case Rep ; 10(1): 129, 2024 May 23.
Article in English | MEDLINE | ID: mdl-38780682

ABSTRACT

BACKGROUND: Pulmonary abscess is a severe infection commonly seen in patients with chronic obstructive pulmonary disease, interstitial pneumonia, immune deficiency disease, drug-induced immunocompromised state, and congenital pulmonary disease. The treatment strategy in pregnant women with a pulmonary abscess is considered challenging since adverse effects on the fetus must be avoided to ensure safe delivery. CASE PRESENTATION: A 34-year-old female patient at 24 weeks of gestation (G2P1) was admitted to the Department of Obstetrics and Gynecology due to sudden right chest pain. The patient had no significant medical history, including congenital anomalies, and no history of drug addiction or smoking. Laboratory data indicated high levels of inflammation (white blood cell 12,000/µL, C-reactive protein 16.0 mg/dL), and computed tomography demonstrated a large intrapulmonary cyst located in the middle of the right lower lobe, with some fluid collection. As the patient had no medical history of congenital pulmonary anomalies, she was initially diagnosed with a pulmonary cyst infection and treated with intravenous antibiotics. However, the infection did not resolve for over a week, and a spike in fever developed after admission. There was no definitive evidence concerning the risk of preterm delivery and fetal abortion during non-obstetric surgery. However, to control the severely infected pulmonary abscess that was refractory to antibiotics and obtain a pathological diagnosis while saving the life of both the mother and fetus, we elected to perform an emergent right lower lobectomy by open thoracotomy with a fissureless maneuver after receiving informed consent. Postoperatively, the infection gradually improved, and the patient was discharged on the 16th postoperative day without any major complications in the mother or fetus. Although she later experienced coronavirus disease-19 at 29 weeks of gestation, a boy was born at 40th weeks of gestation without any complications. Pathologically, no infectious agents, malignancies, or congenital anomalies other than lung abscesses associated with the pulmonary infarction were observed. The mother and child were healthy 1 year postoperatively. CONCLUSIONS: We experienced a rare case of a pulmonary abscess in a pregnant woman who needed an emergent right lower lobectomy to control the severe infection and obtain a correct pathological diagnosis. Under cooperation from an obstetrician and anesthesiologist, emergency pulmonary resection can be performed safely for serious abscess formation even for pregnant women who have several months left until delivery.

3.
PLoS One ; 13(8): e0203067, 2018.
Article in English | MEDLINE | ID: mdl-30153298

ABSTRACT

Perinatal hypertensive disorder including pre-eclampsia is a systemic syndrome that occurs in 3-5% of pregnant women. It can result in various degrees of brain damage. A recent study suggested that even gestational hypertension without proteinuria can cause cardiovascular or cognitive impairments later in life. We hypothesized that perinatal hypertension affects the brain functional connectivity (FC) regardless of the clinical manifestation of brain functional impairment. In the present study, we analyzed regional global connectivity (rGC) strength (mean cross-correlation coefficient between a brain region and all other regions) using resting-state functional magnetic resonance imaging to clarify brain FC changes associated with perinatal blood pressure using data from 16 women with a normal pregnancy and 21 pregnant women with pre-eclampsia. The rGC values in the bilateral orbitofrontal gyri were negatively correlated with diastolic blood pressure (dBP), which could not be explained by other pre-eclampsia symptoms. The strength of FC seeding at the left orbitofrontal gyrus was negatively correlated with dBP in the anterior cingulate gyri and right middle frontal gyrus. These results suggest that dBP elevation during pregnancy can affect the brain FC. Since FC is known to be associated with various brain functions and diseases, our findings are important for elucidating the neural correlate of cognitive impairments related to hypertension in pregnancy.


Subject(s)
Brain/diagnostic imaging , Brain/physiopathology , Pre-Eclampsia/diagnostic imaging , Pre-Eclampsia/physiopathology , Adult , Biomarkers/blood , Blood Pressure/physiology , Brain Mapping , Female , Humans , Magnetic Resonance Imaging , Neural Pathways/diagnostic imaging , Neural Pathways/physiopathology , Pregnancy , Pregnancy Trimester, Third , Rest , Young Adult
4.
J Obstet Gynaecol Res ; 44(8): 1415-1423, 2018 Aug.
Article in English | MEDLINE | ID: mdl-29888832

ABSTRACT

AIM: We compared the perinatal outcomes of vaginal delivery with epidural analgesia initiated at the early versus late phase in a Japanese population. METHODS: Women enrolled in this retrospective cohort study received intrapartum analgesia via combined spinal epidural analgesia after labor onset between May 2010 and August 2015. We compared the perinatal outcomes between two different timings of epidural analgesia: at the early phase (≤3 cm cervical dilatation) and the late phase (≥4 cm) or at the new definition-based early phase (≤5 cm) and late phase (≥6 cm). RESULTS: One hundred twenty-eight singleton pregnant women were eligible. In nulliparous women, there was no marked difference in perinatal outcomes between the early and late phase except for in the first-stage labor period (13.7 h vs 10.1 h, P = 0.016). In multiparous women, there was no marked difference in perinatal outcomes between the early and late phase except for a higher proportion of Apgar score ≤7 at 1 min in the early phase (20.0% vs 0.0%, P = 0.033). In nulliparous women, the first-stage labor period in the new early phase was significantly longer than in the new late phase (13.3 h vs 6.9 h, P = 0.035). Other variables for nulliparous women and all for multiparous women were not different between the new early and late phases. CONCLUSION: Most perinatal outcomes between the early and late phases of initiated epidural analgesia were not markedly different in our Japanese population, even when using a new definition of labor phase.


Subject(s)
Analgesia, Epidural/statistics & numerical data , Analgesia, Obstetrical/statistics & numerical data , Labor Onset , Pregnancy Outcome/epidemiology , Adult , Analgesia, Epidural/methods , Analgesia, Obstetrical/methods , Female , Humans , Japan/epidemiology , Pregnancy , Retrospective Studies , Young Adult
5.
Curr Pharm Des ; 20(36): 5727-37, 2014.
Article in English | MEDLINE | ID: mdl-24502572

ABSTRACT

K(+) channels play an essential role in the membrane potential of arterial smooth muscle, and also in regulating contractile tone. Especially, in vascular smooth muscle, the opening of adenosine triphosphate (ATP)-sensitive K(+) (KATP) channels leads to membrane hyperpolarization, resulting in muscle relaxation and vasodilation. This activation also plays a role in tissues during pathophysiologic events such as ischemia, hypoxia, and vasodilatory shock. In this review, we will describe the physiological and pathophysiological roles of vascular smooth muscle KATP channels in relation to the effects of anesthetics. Although accumulated evidence suggests that many anesthetics modify the above function of K(+) channels as a metabolic sensor, further studies are certainly needed to resolve certain issues, especially in clinical settings of anesthesia use.


Subject(s)
Anesthetics/pharmacology , Muscle, Smooth, Vascular/drug effects , Potassium Channels/drug effects , Animals , Humans , Hypoxia/physiopathology , Ischemia/physiopathology , KATP Channels/drug effects , KATP Channels/metabolism , Membrane Potentials/physiology , Muscle, Smooth, Vascular/metabolism , Muscle, Smooth, Vascular/physiopathology , Potassium Channels/metabolism , Shock/physiopathology , Vasodilation/physiology
7.
PLoS One ; 7(2): e31258, 2012.
Article in English | MEDLINE | ID: mdl-22355350

ABSTRACT

The receptor tyrosine kinase RET plays an essential role during embryogenesis in regulating cell proliferation, differentiation, and migration. Upon glial cell line-derived neurotrophic factor (GDNF) stimulation, RET can trigger multiple intracellular signaling pathways that in concert activate various downstream effectors. Here we report that the RET receptor induces calcium (Ca(2+)) signaling and regulates neocortical neuronal progenitor migration through the Phospholipase-C gamma (PLCγ) binding domain Tyr1015. This signaling cascade releases Ca(2+) from the endoplasmic reticulum through the inositol 1,4,5-trisphosphate receptor and stimulates phosphorylation of ERK1/2 and CaMKII. A point mutation at Tyr1015 on RET or small interfering RNA gene silencing of PLCγ block the GDNF-induced signaling cascade. Delivery of the RET mutation to neuronal progenitors in the embryonic ventricular zone using in utero electroporation reveal that Tyr1015 is necessary for GDNF-stimulated migration of neurons to the cortical plate. These findings demonstrate a novel RET mediated signaling pathway that elevates cytosolic Ca(2+) and modulates neuronal migration in the developing neocortex through the PLCγ binding domain Tyr1015.


Subject(s)
Calcium Signaling/physiology , Cell Movement , Neocortex/metabolism , Neurons/cytology , Phospholipase C gamma/metabolism , Phosphotyrosine/metabolism , Proto-Oncogene Proteins c-ret/metabolism , Animals , Apoptosis , Blotting, Western , Cell Proliferation , Cells, Cultured , Embryo, Mammalian/cytology , Embryo, Mammalian/metabolism , Glial Cell Line-Derived Neurotrophic Factor/genetics , Glial Cell Line-Derived Neurotrophic Factor/metabolism , Humans , Immunoenzyme Techniques , Inositol 1,4,5-Trisphosphate Receptors/genetics , Inositol 1,4,5-Trisphosphate Receptors/metabolism , Mice , Neocortex/embryology , Neurons/metabolism , Phospholipase C gamma/antagonists & inhibitors , Phospholipase C gamma/genetics , Phosphorylation , Proto-Oncogene Proteins c-ret/genetics , RNA, Messenger/genetics , RNA, Small Interfering/genetics , Real-Time Polymerase Chain Reaction
9.
Anesth Analg ; 109(6): 1935-42, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19923524

ABSTRACT

BACKGROUND: We conducted this study to examine, in cerebral parenchymal arterioles, whether 20-hydroxyeicosatetraenoic acid (20-HETE) induces constrictor responses via superoxide and whether propofol reduces this constriction. METHODS: Electrical field stimulation or 20-HETE was applied to rat brain slices monitored by computer-assisted microscopy. In some experiments, a Na(+) channel antagonist tetrodotoxin, a 20-HETE synthesis inhibitor HET0016, a superoxide scavenger, Tiron, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors diphenyleneiodonium (DPI) and gp91ds-tat, or propofol was added. The superoxide level in the brain slice and the production rate in the absence of slices were evaluated by dihydroethidium fluorescence or cytochrome c reduction with a superoxide-generating system, respectively. RESULTS: Electrical stimulation induced constriction of the cerebral parenchymal arteriole, whereas this response was abolished by tetrodotoxin, HET0016, Tiron, or DPI. 20-HETE (10(-8)-10(-6) mol/L) produced arteriolar constriction, which was inhibited by Tiron or DPI. Propofol reduced the constriction induced by electrical stimulation or 20-HETE. 20-HETE induced superoxide production in the brain slice, which was reduced by Tiron, gp91ds-tat, or propofol. However, propofol did not alter the superoxide production rate in the absence of brain slices. CONCLUSIONS: Either neuronal transmission-dependent or exogenous 20-HETE seems to induce cerebral parenchymal arteriolar constriction via superoxide production resulting from NADPH oxidase activation. Propofol is likely to prevent this constriction via inhibition of NADPH oxidase, but not by its scavenging effect on superoxide.


Subject(s)
Anesthetics, Intravenous/pharmacology , Cerebral Arteries/drug effects , Enzyme Inhibitors/pharmacology , Hydroxyeicosatetraenoic Acids/metabolism , NADPH Oxidases/antagonists & inhibitors , Propofol/pharmacology , Vasoconstriction/drug effects , 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt/pharmacology , Amidines/pharmacology , Animals , Arterioles/drug effects , Arterioles/enzymology , Cell-Free System , Cerebral Arteries/enzymology , Electric Stimulation , Free Radical Scavengers/pharmacology , Glycoproteins/pharmacology , In Vitro Techniques , Male , Microscopy, Video , NADPH Oxidases/metabolism , Onium Compounds/pharmacology , Rats , Rats, Wistar , Sodium Channel Blockers/pharmacology , Superoxides/metabolism , Tetrodotoxin/pharmacology , Time Factors
10.
Hypertension ; 52(3): 507-13, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18678787

ABSTRACT

The present study was designed to examine roles of the phosphatidylinositol 3-kinase-Akt pathway and reduced nicotinamide-adenine dinucleotide phosphate oxidases in the reduced ATP-sensitive K(+) channel function via superoxide produced by high glucose in the human artery. We evaluated the activity of the phosphatidylinositol 3-kinase-Akt pathway, as well as reduced nicotinamide-adenine dinucleotide phosphate oxidases, the intracellular levels of superoxide and ATP-sensitive K(+) channel function in the human omental artery without endothelium. Levels of the p85-alpha subunit and reduced nicotinamide-adenine dinucleotide phosphate oxidase subunits, including p47phox, p22phox, and Rac-1, increased in the membrane fraction from arteries treated with D-glucose (20 mmol/L) accompanied by increased intracellular superoxide production. High glucose simultaneously augmented Akt phosphorylation at Ser 473, as well as Thr 308 in the human vascular smooth muscle cells. A phosphatidylinositol 3-kinase inhibitor LY294002, as well as tiron and apocynin, restored vasorelaxation and hyperpolarization in response to an ATP-sensitive K(+) channel opener levcromakalim. Therefore, it can be concluded that the activation of the phosphatidylinositol 3-kinase-Akt pathway, in combination with the translocation of p47phox, p22phox, and Rac-1, contributes to the superoxide production induced by high glucose, resulting in the impairment of ATP-sensitive K(+) channel function in the human visceral artery.


Subject(s)
Arteries/enzymology , Hyperglycemia/metabolism , KATP Channels/metabolism , NADPH Oxidases/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Antihypertensive Agents/pharmacology , Arteries/cytology , Arteries/drug effects , Chromones/pharmacology , Cromakalim/pharmacology , Enzyme Inhibitors/pharmacology , Glucose/pharmacology , Glyburide/pharmacology , Humans , Hyperglycemia/drug therapy , Hypoglycemic Agents/pharmacology , In Vitro Techniques , Morpholines/pharmacology , Muscle, Smooth, Vascular/cytology , Muscle, Smooth, Vascular/drug effects , Muscle, Smooth, Vascular/enzymology , Omentum/blood supply , Phosphorylation , Signal Transduction/drug effects , Signal Transduction/physiology , Superoxides/metabolism , rac1 GTP-Binding Protein/metabolism
11.
Anesthesiology ; 109(1): 124-9, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18580182

ABSTRACT

BACKGROUND: An acetylcholinesterase inhibitor donepezil currently is used to treat patients with Alzheimer disease. However, its direct effect on cerebral blood vessels has not been evaluated. The present study was designed to examine whether donepezil induces acute cerebral arteriolar dilation and whether neuronal nitric oxide synthase contributes to this vasodilator response. METHODS: Brain slices were obtained from neuronal nitric oxide synthase knock-out or C57BL/6J strain (control) mice as well as Wistar rats. Parenchymal arterioles were monitored using videomicroscopy. During constriction to prostaglandin F2alpha (5 x 10 m), donepezil (10-10 m) or acetylcholine (10-10 m) was added. In some experiments, brain slices were treated with a nonselective or a selective nitric oxide synthase inhibitor (N-nitro-L-arginine methyl ester [10 m] and S-methyl-L-thiocitrulline [10 m], respectively). An immunohistochemical analysis was performed using antibodies for neuronal nitric oxide synthase and acetylcholinesterase. RESULTS: Acetylcholine concentration-dependently dilated rat parenchymal arterioles, while S-methyl-L-thiocitrulline as well as N-nitro-L-arginine methyl ester completely abolished this response. Donepezil produced arteriolar dilation, which was inhibited by S-methyl-L-thiocitrulline or N-nitro-L-arginine methyl ester. Donepezil failed to induce arteriolar dilation in the brain slice from the neuronal nitric oxide synthase knock-out mice. Immunohistochemical analysis revealed spatial relationship between neuronal nitric oxide synthase and acetylcholinesterase in the arteriolar wall. CONCLUSIONS: Donepezil produces acute vasodilation induced by a selective activation of neuronal nitric oxide synthase in the cerebral parenchymal arterioles. This agent may be capable of enhancing this enzymatic activity directly or via acetylcholinesterase existing on the arteriolar wall.


Subject(s)
Brain/blood supply , Brain/enzymology , Cholinesterase Inhibitors/pharmacology , Indans/pharmacology , Nitric Oxide Synthase Type I/metabolism , Piperidines/pharmacology , Vasodilation/physiology , Animals , Arterioles/drug effects , Arterioles/enzymology , Brain/drug effects , Donepezil , Enzyme Activation/drug effects , Enzyme Activation/physiology , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Nitric Oxide Synthase Type I/physiology , Rats , Rats, Wistar , Vasodilation/drug effects
12.
Anesthesiology ; 108(2): 269-75, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18212572

ABSTRACT

BACKGROUND: Vascular dysfunction induced by hyperglycemia has not been studied in cerebral parenchymal circulation. The current study was designed to examine whether high glucose impairs dilation of cerebral parenchymal arterioles via nitric oxide synthase, and whether propofol recovers this vasodilation by reducing superoxide levels in the brain. METHODS: Cerebral parenchymal arterioles in the rat brain slices were monitored using computer-assisted videomicroscopy. Vasodilation induced by acetylcholine (10 to 10 m) was obtained after the incubation of brain slices for 60 min with any addition of l-glucose (20 mm), d-glucose (20 mm), or propofol (3 x 10 or 10 m) in combination with d-glucose (20 mm). Superoxide production in the brain slice was determined by dihydroethidium (2 x 10 m) fluorescence. RESULTS: Addition of d-glucose, but not l-glucose, reduced arteriolar dilation by acetylcholine, whereas the dilation was abolished by the neuronal nitric oxide synthase inhibitor S-methyl-l-thiocitrulline (10 m). Both propofol and the superoxide dismutase mimetic Tempol (10 m) restored the arteriolar dilation in response to acetylcholine in the brain slice treated with d-glucose. Addition of d-glucose increased superoxide production in the brain slice, whereas propofol, Tempol, and the nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase inhibitor apocynin (1 mm) similarly inhibited it. CONCLUSIONS: Clinically relevant concentrations of propofol ameliorate neuronal nitric oxide synthase-dependent dilation impaired by high glucose in the cerebral parenchymal arterioles via the effect on superoxide levels. Propofol may be protective against cerebral microvascular malfunction resulting from oxidative stress by acute hyperglycemia.


Subject(s)
Arterioles/physiology , Cerebrovascular Circulation/physiology , Glucose/pharmacology , Microcirculation/physiology , Oxidative Stress/physiology , Propofol/pharmacology , Venules/physiology , Animals , Arterioles/drug effects , Cerebrovascular Circulation/drug effects , In Vitro Techniques , Male , Microcirculation/drug effects , Microscopy, Video , Oxidative Stress/drug effects , Rats , Rats, Wistar , Thoracotomy , Venules/drug effects
13.
Masui ; 56(9): 1025-31; discussion 1044-6, 2007 Sep.
Article in Japanese | MEDLINE | ID: mdl-17877042

ABSTRACT

Labor epidural analgesia is unfamiliar to parturients in Wakayama Prefecture partly because of insufficient information and medical services for expectant mothers given by anesthesiologists and other medical staffs. We offered introductory approaches for providing epidural analgesia for labor and delivery in our obstetric care unit. The preliminary survey among midwives, who are crucial for gravitas, revealed their negative attitude to painless labor assisted by epidural technique, while they opted for natural childbirth. Obstetricians also responded negatively toward epidural analgesia during labor because of their concern about forceps and prolonged delivery. We spent considerable time to achieve better communication with midwives and obstetricians in order to improve our professional qualities for caring labor pain. After practical approach of labor epidural analgesia, midwives came to accept epidural analgesia as an option during childbirth.


Subject(s)
Analgesia, Epidural , Analgesia, Obstetrical , Analgesia, Patient-Controlled , Anesthesiology , Attitude of Health Personnel , Female , Humans , Japan , Midwifery , Obstetrics , Physicians/psychology , Pregnancy , Quality of Health Care , Surveys and Questionnaires
14.
Anesth Analg ; 105(2): 325-9, 2007 Aug.
Article in English | MEDLINE | ID: mdl-17646484

ABSTRACT

BACKGROUND: Sphingosylphosphorylcholine may induce coronary vasospasm by the activation of Rho kinase. We designed the current study to examine the differential effects of anesthetics on Rho kinase activation induced by sphingosylphosphorylcholine in porcine coronary arteries. METHODS: Rings of porcine coronary artery without endothelium were prepared in tissue bath containing modified Krebs-Ringer bicarbonate solution. Using isometric force recording, concentration-response curves in response to sphingosylphosphorylcholine were obtained in the absence or in the presence of sevoflurane, propofol, or a selective Rho kinase inhibitor Y27632, which was added 15 min before the application of sphingosylphosphorylcholine. Intracellular translocation of Rho A toward the plasma membrane and phosphorylation of the myosin-targeting subunit of myosin light chain phosphatase were also evaluated by Western blotting. RESULTS: Sphingosylphosphorylcholine (10(-7) to 10(-5) M) produced contraction of the porcine coronary artery, which was abolished by a selective Rho kinase inhibitor Y27632 (2 x 10(-6) M). Sevoflurane (1.7%) reduced sphingosylphosphorylcholine-induced coronary artery constriction, and the higher concentration (3.4%) abolished it (P < 0.05). In contrast, propofol (3 x 10(-6) M and 10(-5) M) had no effect on coronary artery constriction due to sphingosylphosphorylcholine. Sevoflurane, but not propofol, reduced intracellular translocation of Rho A toward the plasma membrane. Sevoflurane and Y27632, but not propofol, similarly decreased (64.4% or 70.8% reduction, respectively, P < 0.05) phosphorylation of the myosin-targeting subunit of myosin light chain phosphatase. CONCLUSIONS: Sphingosylphosphorylcholine induces coronary vasocontriction via activation of Rho kinase. Sevoflurane, but not propofol, inhibits this pathway, resulting in prevention of vasoconstriction.


Subject(s)
Coronary Vessels/drug effects , Coronary Vessels/enzymology , Intracellular Signaling Peptides and Proteins/metabolism , Methyl Ethers/pharmacology , Phosphorylcholine/analogs & derivatives , Propofol/pharmacology , Protein Serine-Threonine Kinases/metabolism , Sphingosine/analogs & derivatives , Vasoconstriction/drug effects , Animals , Dose-Response Relationship, Drug , Phosphorylcholine/pharmacology , Sevoflurane , Sphingosine/pharmacology , Swine , Vasoconstriction/physiology , rho-Associated Kinases
16.
J Pharmacol Exp Ther ; 318(1): 312-8, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16574781

ABSTRACT

The present study was designed to examine whether in the human artery, synthetic peroxisome proliferator-activated receptor (PPAR)-gamma agonists restore vasorelaxation as well as hyperpolarization via ATP-sensitive K+ channels impaired by the high concentration of D-glucose and whether the restoration may be mediated by the antioxidant capacity of these agents. The isometric force and membrane potential of human omental arteries without endothelium were recorded. The production rate of superoxide was evaluated using a superoxide-generating system with xanthine-xanthine oxidase in the absence of smooth muscle cells. Glibenclamide abolished vasorelaxation and hyperpolarization in response to levcromakalim. Addition of D-glucose (20 mM) but not L-glucose (20 mM) reduced this vasorelaxation and hyperpolarization. Synthetic PPAR-gamma agonists (troglitazone and rosiglitazone) and/or an inhibitor of superoxide generation (4,5-dihydroxy-1,3-benzene-disulfonic acid, Tiron), but not a PPAR-alpha agonist (fenofibrate), restored vasorelaxation and hyperpolarization in response to levcromakalim in arteries treated with D-glucose. Troglitazone and rosiglitazone, but not fenofibrate, decreased the production rate of superoxide without affecting uric acid generation. These findings suggest that synthetic PPAR-gamma agonists recover the function of ATP-sensitive K+ channels reduced by the high concentration of glucose in human vascular smooth muscle cells and that the effect of these agonists may be mediated in part by their antioxidant capacity.


Subject(s)
Adenosine Triphosphate/physiology , Glucose/administration & dosage , PPAR gamma/agonists , Potassium Channels/physiology , Vasodilation/physiology , Aged , Cromakalim/pharmacology , Dose-Response Relationship, Drug , Female , Glucose/physiology , Glucose/toxicity , Humans , Male , Middle Aged , PPAR gamma/physiology , Vascular Diseases/chemically induced , Vascular Diseases/physiopathology , Vasodilation/drug effects
17.
Anesth Analg ; 102(3): 786-91, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16492829

ABSTRACT

Droperidol produces the inhibition of K+ channels in cardiac myocytes. However, the effects of droperidol on K+ channels have not been studied in blood vessels. Therefore, we designed the present study to determine whether droperidol modulates the activity of adenosine triphosphate (ATP)-sensitive K+ channels in vascular smooth muscle cells. Rat aortic rings without endothelium were suspended or used for isometric force and membrane potential recordings, respectively. Vasorelaxation and hyperpolarization induced by levcromakalim (10(-8) to 10(-5) M or 10(-5) M, respectively) were completely abolished by the ATP-sensitive K+ channel antagonist glibenclamide (10(-5) M). Droperidol (10(-7) M) and an alpha-adrenergic receptor antagonist phentolamine (3 x 10(-9) M) caused a similar vasodilator effect (approximately 20% of vasorelaxation compared with maximal vasorelaxation induced by papaverine [3 x 10(-4) M]), whereas glibenclamide did not alter vasorelaxation induced by droperidol. Droperidol (3 x 10(-8) M to 10(-7) M) augmented vasorelaxation and hyperpolarization produced by levcromakalim, whereas phentolamine (3 x 10(-9) M) did not alter this vasorelaxation. Glibenclamide (10(-5) M) abolished the vasodilating and hyperpolarizing effects of levcromakalim in the aorta treated with droperidol (10(-7) M). These results suggest that droperidol augments vasodilator activity via ATP-sensitive K+ channels. However, it is unlikely that this augmentation is mediated by the inhibition of alpha-adrenergic receptors in vascular smooth muscles.


Subject(s)
Adenosine Triphosphate/physiology , Aorta, Thoracic/drug effects , Droperidol/pharmacology , Potassium Channels/physiology , Animals , Aorta, Thoracic/physiology , Cromakalim/pharmacology , Dose-Response Relationship, Drug , Drug Synergism , In Vitro Techniques , Male , Rats , Rats, Wistar , Vasodilation/drug effects , Vasodilation/physiology
19.
Anesth Analg ; 102(2): 571-6, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16428563

ABSTRACT

Although inward rectifier K+ channels contribute to the regulation of cerebral circulation, dilation of cerebral microvasculature mediated by these channels has not been demonstrated in chronic hypertension. We designed the present study to examine the roles of inward rectifier K+ channels in the vasodilation produced by increased levels of extracellular K+ in cerebral parenchymal arterioles from hypertensive and normotensive rats. During constriction to prostaglandin F2alpha (5 x 10(-7) M), the arterioles within brain slices were evaluated using computer-assisted microscopy. Potassium chloride (KCl) induced vasodilation in cerebral arterioles from normotensive (5-10 mM) and hypertensive (5-15 mM) rats, whereas an inward rectifier K+ channel antagonist barium chloride (BaCl2; 10(-5) M) completely abolished the vasodilation in both strains. In arterioles of hypertensive rats, vasodilator responses to KCl were augmented compared with those in normotensive rats. In contrast, the vasodilator responses induced by sodium nitroprusside (3 x 10(-8) to 3 x 10(-6) M) in these two strains were similar. These results suggest that in cerebral cortex parenchymal microvessels, inward rectifier K+ channels play a crucial role in vasodilation produced by extracellular K+ and that the dilation of cerebral arterioles via these channels is augmented in chronic hypertension.


Subject(s)
Brain/blood supply , Hypertension/physiopathology , Potassium Channels, Inwardly Rectifying/physiology , Potassium Chloride/pharmacology , Vasodilation/physiology , Animals , Arterioles/anatomy & histology , Arterioles/physiology , Barium Compounds/pharmacology , Blood Pressure/drug effects , Cerebrovascular Circulation , Chlorides/pharmacology , Dinoprost/pharmacology , Dose-Response Relationship, Drug , Male , Nitroprusside/pharmacology , Potassium Channels, Inwardly Rectifying/antagonists & inhibitors , Rats , Rats, Inbred SHR , Rats, Inbred WKY , Vasoconstriction/drug effects , Vasoconstrictor Agents/pharmacology , Vasodilation/drug effects
20.
Can J Anaesth ; 52(3): 254-7, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15753495

ABSTRACT

PURPOSE: Beta-adrenergic receptor antagonists (beta-antagonists) have long been used to control perioperative tachyarrhythmias. The effects of a beta(1)-antagonist, landiolol, on perioperative hemodynamics are unknown. We aimed to determine the appropriate dosage of landiolol for the treatment of hemodynamic changes in response to endotracheal intubation. METHODS: Sixty-four patients without heart disease or hypertension, were assigned to receive saline (group C) or landiolol (0.1 or 0.3 mg.kg(-1); groups L1 and L3). Anesthesia was induced with propofol (2 mg.kg(-1) iv) followed by saline or landiolol iv. After ventilation with facemask using 2% sevoflurane in 100% oxygen for 90 sec, endotracheal intubation was performed. After intubation, anesthesia was maintained using 1% sevoflurane in combination with 50% nitrous oxide. Values of heart rate and mean arterial blood pressure were recorded before induction to five minutes after intubation. RESULTS: In group C, heart rate and mean blood pressure increased simultaneously after tracheal intubation, compared with baseline values. Heart rate values were attenuated immediately before as well as after intubation in group L3, compared with groups C and L1. Heart rate did not increase after tracheal intubation in group L1, compared with baseline. In contrast, mean arterial blood pressure values did not differ among groups. CONCLUSIONS: The newly developed beta(1)-antagonist landiolol (0.1 and 0.3 mg.kg(-1)) may help prevent tachycardia without affecting blood pressure during the induction of anesthesia.


Subject(s)
Adrenergic beta-Antagonists/pharmacology , Blood Pressure/drug effects , Heart Rate/drug effects , Intubation, Intratracheal , Morpholines/pharmacology , Urea/analogs & derivatives , Urea/pharmacology , Adult , Aged , Double-Blind Method , Humans , Middle Aged
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