28 results match your criteria propagate distally

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Effect of saw blade geometry on crack initiation and propagation on the lateral cortical hinge for HTO: Finite element analysis.

Orthop Traumatol Surg Res 2019 10 22;105(6):1079-1083. Epub 2019 Aug 22.

Laboratoire ICube, équipe MMB, 67400 Illkirch, France.

Introduction: The hinge plays a primary role in the hold and healing of a high tibial osteotomy (HTO). Weakening of the hinge is a risk factor for failure. The aim of our study was to determine whether the geometry of the saw blade's cutting edge impacts crack initiation or propagation on the hinge. Read More

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October 2019

Astrocyte calcium waves propagate proximally by gap junction and distally by extracellular diffusion of ATP released from volume-regulated anion channels.

Sci Rep 2017 10 13;7(1):13115. Epub 2017 Oct 13.

Kobe University Graduate School of Science, Department of Biology, Kobe, 657-8501, Japan.

Wave-like propagation of [Ca] increases is a remarkable intercellular communication characteristic in astrocyte networks, intercalating neural circuits and vasculature. Mechanically-induced [Ca] increases and their subsequent propagation to neighboring astrocytes in culture is a classical model of astrocyte calcium wave and is known to be mediated by gap junction and extracellular ATP, but the role of each pathway remains unclear. Pharmacologic analysis of time-dependent distribution of [Ca] revealed three distinct [Ca] increases, the largest being in stimulated cells independent of extracellular Ca and inositol 1,4,5-trisphosphate-induced Ca release. Read More

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October 2017

Focal cortical seizures start as standing waves and propagate respecting homotopic connectivity.

Nat Commun 2017 08 9;8(1):217. Epub 2017 Aug 9.

UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK.

Focal epilepsy involves excessive cortical activity that propagates both locally and distally. Does this propagation follow the same routes as normal cortical activity? We pharmacologically induced focal seizures in primary visual cortex (V1) of awake mice, and compared their propagation to the retinotopic organization of V1 and higher visual areas. We used simultaneous local field potential recordings and widefield imaging of a genetically encoded calcium indicator to measure prolonged seizures (ictal events) and brief interictal events. Read More

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Moesin and merlin regulate urokinase receptor-dependent endothelial cell migration, adhesion and angiogenesis.

Int J Biochem Cell Biol 2017 07 1;88:14-22. Epub 2017 May 1.

Centre of Preventive Medicine, School of Health and Human Performance, Faculty of Science and Health, Dublin City University, Glasnevin, Dublin 9, Ireland.

The glycosyl-phosphatidyl-inositol (GPI)-anchored urokinase receptor (uPAR) has no intracellular domain, but nevertheless initiates signalling through proximal interactions with other membrane receptors including integrins. The relationships between uPAR and ezrin/radixin/moesin (ERM) proteins, moesin and merlin have never been explored. Moesin and merlin are versatile membrane-actin links and regulators of receptors signalling, respectively. Read More

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Therapeutic mechanisms of high-frequency stimulation in Parkinson's disease and neural restoration via loop-based reinforcement.

Proc Natl Acad Sci U S A 2015 Feb 26;112(6):E586-95. Epub 2015 Jan 26.

Institute for Computational Medicine and Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD 21218;

High-frequency deep brain stimulation (HFS) is clinically recognized to treat parkinsonian movement disorders, but its mechanisms remain elusive. Current hypotheses suggest that the therapeutic merit of HFS stems from increasing the regularity of the firing patterns in the basal ganglia (BG). Although this is consistent with experiments in humans and animal models of Parkinsonism, it is unclear how the pattern regularization would originate from HFS. Read More

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February 2015

Formation of the statolith in the ctenophore Mnemiopsis leidyi.

Authors:
Sidney L Tamm

Biol Bull 2014 Aug;227(1):7-18

Bell Center, Marine Biological Laboratory, Woods Hole, Massachusetts 02543

The aboral sensory organ (apical organ) of ctenophores contains a statocyst with a single large statolith. The statolith comprises living cells (lithocytes), each containing a large membrane-bound concretion. The statolith is supported on the distal ends of four compound motile mechanoresponsive cilia (balancers) which control the beat frequencies of the eight locomotory comb rows, and thereby the orientation of animals to gravity. Read More

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Intussuception at atypical ages in children and adults--11 years experiences.

Pol Przegl Chir 2011 Jun;83(6):304-9

Department of Pediatric Surgery, Imam Khomeini Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Unlabelled: Intussusception is a curious anatomic condition characterized by the invagination of one segment of the gastrointestinal tract into the lumen of an adjacent segment. Once initiated, additional intestinal telescopes into the distal segment, causing the invaginated intestine to propagate distally within the bowel lumen. The aim of the study was to evaluate the clinical manifestation, etiology, and outcome of intussuception at atypical ages. Read More

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Redefining the gonadotrophin-releasing hormone neurone dendrite.

J Neuroendocrinol 2010 Jul 18;22(7):650-8. Epub 2010 May 18.

Department of Physiology and Centre for Neuroendocrinology, University of Otago School of Medical Sciences, Dunedin, New Zealand.

Gonadotrophin-releasing hormone (GnRH) neurones are the final output neurones of the complex synaptic network responsible for the central control of fertility. This scattered population of neurones has been shown to have remarkably long dendritic processes by cell-filling of GnRH neurones in situ with low-molecular weight dyes. This review focuses on how the functional significance of these long dendritic extensions is being explored through dual somatic-dendritic electrophysiological recordings, computational modelling, immunolabelling for specific channels and multiple modes of microscopy and imaging. Read More

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The structure of the cornified claw sheath in the domesticated cat (Felis catus): implications for the claw-shedding mechanism and the evolution of cornified digital end organs.

J Anat 2009 Apr;214(4):620-43

Department of Biological Sciences, Louisiana State University, Baton Rouge, 70803-1715, USA.

The morphology of cornified structures is notoriously difficult to analyse because of the extreme range of hardness of their component tissues. Hence, a correlative approach using light microscopy, scanning electron microscopy, three-dimensional reconstructions based on x-ray computed tomography data, and graphic modeling was applied to study the morphology of the cornified claw sheath of the domesticated cat as a model for cornified digital end organs. The highly complex architecture of the cornified claw sheath is generated by the living epidermis that is supported by the dermis and distal phalanx. Read More

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Biomagnetic signatures of uncoupled gastric musculature.

Neurogastroenterol Motil 2009 Jul 15;21(7):778-e50. Epub 2009 Feb 15.

Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37235, USA.

Gastric slow waves propagate in the electrical syncytium of the healthy stomach, being generated at a rate of approximately three times per minute in a pacemaker region along the greater curvature of the antrum and propagating distally towards the pylorus. Disease states are known to alter the normal gastric slow wave. Recent studies have suggested the use of biomagnetic techniques for assessing parameters of the gastric slow wave that have potential diagnostic significance. Read More

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Modulation of calcium wave propagation in the dendrites and to the soma of rat hippocampal pyramidal neurons.

J Physiol 2006 Sep 29;575(Pt 2):455-68. Epub 2006 Jun 29.

Department of Physiology, New York Medical College, Valhalla, NY 10595, USA.

Repetitive synaptic stimulation in the stratum radiatum (SR) evokes large amplitude Ca2+ waves in the thick apical dendrites of hippocampal CA1 pyramidal neurons. These waves are initiated by activation of metabotropic glutamate receptors (mGluRs), which mobilize inositol-1,4,5-trisphospate (IP3) and release Ca2+ from intracellular stores. We explored mechanisms that modulate the spatial properties of these waves. Read More

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September 2006

Fidelity in planar cell polarity signalling.

Nature 2003 Jan 19;421(6922):543-7. Epub 2003 Jan 19.

Department of Pathology, Stanford University School of Medicine, Stanford, California 94305-5324, USA.

The polarity of Drosophila wing hairs displays remarkable fidelity. Each of the approximately 30,000 wing epithelial cells constructs an actin-rich prehair that protrudes from its distal vertex and points distally. The distal location and orientation of the hairs is virtually error free, thus forming a nearly perfect parallel array. Read More

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January 2003

Distal projection of insufflated gas during tracheal gas insufflation.

J Appl Physiol (1985) 2002 May;92(5):1843-50

Regions Hospital, St. Paul, MN 55101, USA.

Tracheal gas insufflation (TGI) flushes expired gas from the ventilator circuitry and central airways, augmenting CO2 clearance. Whereas a significant portion of this washout effect may occur distal to the injection orifice, the penetration and mixing behavior of TGI gas has not been studied experimentally. We examined the behavior of 100% oxygen TGI injected at set flow rates of 1-20 l/min into a simulated trachea consisting of a smooth-walled, 14-mm-diameter tube. Read More

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Pyeloureteral motility and ureteral peristalsis: essential role of sensory nerves and endogenous prostaglandins.

Exp Physiol 2002 Mar;87(2):129-46

Department of Physiology, Monash University, Clayton, Victoria 3800, Australia.

The cellular mechanisms that underlie the initiation and propagation of the peristaltic contractions, which transport urine from the kidney to the bladder for storage, remain little understood. Extracellular and intracellular microelectrode recordings have identified two populations of smooth muscle cells as well as a population of renal interstitial cells (RICs) that all display spontaneous electrical activity. By analogy with the heart it has been proposed that atypical smooth muscle cells, preferentially located in the very proximal regions of the renal pelvis, generate the essential pacemaker signal. Read More

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Hippocampal mossy fiber activity evokes Ca2+ release in CA3 pyramidal neurons via a metabotropic glutamate receptor pathway.

Neuroscience 2001 ;107(1):59-69

Division of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.

Mossy fiber activity can evoke Ca2+ release from internal stores in CA3 neurons, but the physiological conditions under which this occurs and the mechanisms underlying the release are not understood. Using rat hippocampal slices we report here that short trains of mossy fiber stimulation activate group I metabotropic glutamate receptors (mGluRs) on CA3 pyramidal neurons and elicit waves of Ca2+ release from inositol 1,4,5-trisphosphate (IP3) sensitive internal stores that propagate from stratum lucidum to the soma and in some cases distally out the dendrites. Activation of mGluR1,5 receptors by an agonist trans-azetidine-2,4-dicarboxylic acid (tADA) applied to stratum lucidum was also sufficient to induce waves of Ca2+ release. Read More

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February 2002

Site independence of EPSP time course is mediated by dendritic I(h) in neocortical pyramidal neurons.

J Neurophysiol 2000 May;83(5):3177-82

Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, ACT 0200, Australia.

Neocortical layer 5 pyramidal neurons possess long apical dendrites that receive a significant portion of the neurons excitatory synaptic input. Passive neuronal models indicate that the time course of excitatory postsynaptic potentials (EPSPs) generated in the apical dendrite will be prolonged as they propagate toward the soma. EPSP propagation may, however, be influenced by the recruitment of dendritic voltage-activated channels. Read More

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Antidromic discharges in dorsal roots of decerebrate cats. I. Studies at rest and during fictive locomotion.

Brain Res 1999 Oct;846(1):87-105

Centre de Recherche en Sciences Neurologiques, Faculté de Médecine, Pavillon Paul-G.-Desmarais, 2960 Chemin de la Tour, Université de Montréal, Montréal, Québec, Canada.

Spontaneous rhythmic antidromic discharges have previously been recorded in proximal stumps of cut dorsal roots during locomotion (real and fictive). The goals of the present study were to elucidate (1) whether both orthodromic and antidromic discharges occur in the same dorsal root filament and (2) whether orthodromic discharges have an influence upon antidromic discharges of units in the same filament. Unitary activity was recorded in 70 uncut dorsal root filaments (L6-S1) in 15 decerebrate cats using bipolar Ag/AgCl electrodes. Read More

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October 1999

Electrocholecystogram: a study of the electromechanical activity of the gall bladder in a canine model.

Authors:
A Shafik

Exp Physiol 1998 May;83(3):387-95

Department of Surgery and Experimental Research, Faculty of Medicine, Cairo University, Egypt.

To characterize an 'electrocholecystogram' (EChG) for the normal gall bladder (GB) that might act as a standard for the evaluation of pathological electrocholecystograms of the diseased GB, ten mongrel dogs (14.4+/-3.2 kg) were studied. Read More

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Electrical basis of peristalsis in the mammalian upper urinary tract.

Clin Exp Pharmacol Physiol 1998 May;25(5):310-21

Department of Physiology, Monash University, Clayton, Victoria, Australia.

1. Peristalsis in the mammalian upper urinary tract (UUT) is mostly myogenic in origin, originating predominately in the proximal pelvicalyceal regions of the renal pelvis, an area that is enriched with specialized smooth muscle cells termed 'atypical' smooth muscle cells. Propagating peristaltic contractions are little affected by blockers of either autonomic nerve function or nerve impulse propagation; however, blockers of sensory nerve function or prostaglandin synthesis reduce both the frequency and the strength of the spontaneous contractions underlying peristalsis. Read More

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Cellular graded responses and ventricular vulnerability to reentry by a premature stimulus in isolated canine ventricle.

Circulation 1997 Apr;95(8):2141-54

Department of Medicine, Cedars-Sinai Medical Center and the University of California, Los Angeles 90048, USA.

Background: The cellular mechanism by which a point strong premature stimulus (S2) induces reentry is unknown. We hypothesized that cellular graded responses induced by an S2 mediate and control tissue vulnerability to reentry.

Methods And Results: Reentry is induced in normal canine ventricular epicardial slices (30x38x2 mm, n=30) by an S2 at intervals shorter than the effective refractory period. Read More

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Microneurography for the recording and selective stimulation of afferents: an assessment.

Muscle Nerve 1988 Jun;11(6):638-44

Department of Physiology, University of Alberta, Edmonton, Canada.

The purpose of this study was to examine whether a microneurography electrode could record from and then selectively stimulate the same afferent fiber in cat sural and tibial nerves. Fiber activity was recorded distally with microneurography needle electrodes and proximally with hook electrodes. Records from the hook electrodes allowed the waveform shape and latency following natural stimulation to be compared with that produced by electrical stimuli delivered through the needle electrode. Read More

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Retrograde air embolization in coronary operations.

J Thorac Cardiovasc Surg 1987 Jul;94(1):110-4

Observations during coronary operations are presented that prove that if the ascending aorta is cross-clamped and suction applied to the left side of the heart or to the aortic root for venting purposes, the pressure rapidly drops in the coronary arterial system and a situation is created in which air may enter through the coronary arteriotomy and pass into the aortic root and the left ventricle. Another mechanism to explain the occurrence of some cases of "iatrogenic" air embolism has also been presented: introduction of air into the ascending aorta while cardioplegic solution is being injected through peripherally attached bypass grafts. Air trapped in these grafts or in the coronary artery itself may propagate proximally as well as distally in the coronary arteries and may reach the aortic root even if the left side of the heart is left unvented. Read More

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Creatine kinase-dependent energy transport in sea urchin spermatozoa. Flagellar wave attenuation and theoretical analysis of high energy phosphate diffusion.

Biophys J 1987 Jul;52(1):75-86

The significance of a phosphocreatine (PCr) shuttle in the energy transport of motile spermatozoa (Tombes, R. M., and B. Read More

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Comparison of the myoelectrical activity of the lateral and J-shaped ileal reservoirs.

J Pediatr Surg 1986 Jun;21(6):500-5

Ileal myoelectrical activity was studied in ten 10-cm J-shaped and ten lateral ileal reservoirs (IR) in rabbits. Electrodes and a strain gauge were placed on both ileal segments of the reservoirs as well as the proximal and distal ileum entering and leaving the reservoirs. In three additional rabbits without reservoirs (controls), electrodes and a strain gauge were sutured to the distal ileum in a similar manner. Read More

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Structure and motility of the 9 + 0 flagellum of eel spermatozoa.

J Submicrosc Cytol 1983 Jan;15(1):15-20

Scanning and electron microscopic study of the spermatozoon of the eel, Anguilla anguilla, has shown that the large oblong head is attached eccentrically by one end to the basal end of the true flagellum and contains a pseudoflagellum that splits into two groups of tubules as it passes around the nucleus. The 9+0 axoneme of the true flagellum lacks outer dynein arms and the radial spoke complex. The movement of Anguilla sperm is characterized by rapid forward progression that is the result of left-handed helicoidal waves propagated distally at a beat frequency at 21 degrees of about 95 Hz. Read More

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January 1983

Electrical and contractile activities of the human rectosigmoid.

Gut 1982 Aug;23(8):698-705

Electrical and mechanical activities were recorded from the rectosigmoid of normal subjects using an intraluminal recording tube with two sets of bipolar electrodes and strain gauges. Four distinct types of electrical activities were recorded. (1) Electrical control activity (ECA). Read More

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Propagation of sepsis in vascular grafts.

Arch Surg 1980 Jul;115(7):878-9

Clinical studies have stated that sepsis tends to remain localized at the point of origin in a patent arterial synthetic graft. We have demonstrated in the pig model that in the acute phase, infection will propagate distally in both thrombotic and patent grafts. The propagation of infection is probably intraluminal. Read More

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Asymmetric waveforms in echinoderm sperm flagella.

Authors:
S F Goldstein

J Exp Biol 1977 Dec;71:157-70

1.Dark-field, multiple-exposure photographs of live spermatozoa of a number of echinoderms were analysed. 2. Read More

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December 1977
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