The effect of needle tip tracking on procedural time of ultrasound-guided lumbar plexus block: a randomised controlled trial.

Technology that facilitates performance of deep peripheral nerve blocks is of clinical interest. The Onvision™ is a new device for ultrasonographic needle tip tracking that incorporates an ultrasound sensor on the needle tip that is then represented by a green circle on the ultrasound screen. The primary aim of this study was to investigate the effect of needle tip tracking on procedural time in the first human volunteer study.

Needle tip tracking for ultrasound-guided peripheral nerve block procedures-An observer blinded, randomised, controlled, crossover study on a phantom model.

Background: The Onvision needle tip tracking (NTT) is a new technology consisting of a needle with an ultrasound sensor close to the needle tip and a console for computerised signal processing. The aim of the study was to evaluate NTT technology during ultrasound-guided simulated peripheral nerve block procedures in a porcine phantom model.

Methods: Forty anaesthesiologists performed in-plane and out-of-plane simulated nerve blocks with and without NTT guidance.

First Experience With Rectus Sheath Block for Postoperative Analgesia After Pancreas Transplant: A Retrospective Observational Study.

Background: Standard of care for postoperative analgesia after pancreas transplant has been thoracic epidural analgesia (TEA). A high incidence of venous graft thrombosis necessitated a change to a more aggressive anticoagulation protocol. To minimize the risk of epidural hemorrhages, we changed from TEA to rectus sheath block (RSB) in 2017.

The Analgesic Effect of Ultrasound-Guided Quadratus Lumborum Block After Cesarean Delivery: A Randomized Clinical Trial.

Background: Landmark and ultrasound-guided transversus abdominis plane blocks have demonstrated an opioid-sparing effect postoperatively after cesarean delivery. The more posterior quadratus lumborum (QL) might provide superior local anesthetic spread to the thoracolumbar fascia and paravertebral space. The aim of our study was to evaluate the efficacy of the QL block after cesarean delivery.

Detection of needle to nerve contact based on electric bioimpedance and machine learning methods.

In an ongoing project for electrical impedance-based needle guidance we have previously showed in an animal model that intraneural needle positions can be detected with bioimpedance measurement. To enhance the power of this method we in this study have investigated whether an early detection of the needle only touching the nerve also is feasible. Measurement of complex impedance during needle to nerve contact was compared with needle positions in surrounding tissues in a volunteer study on 32 subjects.

Ultrasound-guided lumbar plexus block in volunteers; a randomized controlled trial.

Background: The currently best-established ultrasound-guided lumbar plexus block (LPB) techniques use a paravertebral location of the probe, such as the lumbar ultrasound trident (LUT). However, paravertebral ultrasound scanning can provide inadequate sonographic visibility of the lumbar plexus in some patients. The ultrasound-guided shamrock LPB technique allows real-time sonographic viewing of the lumbar plexus, various anatomical landmarks, advancement of the needle, and spread of local anaesthetic injectate in most patients.

The Shamrock lumbar plexus block: A dose-finding study.

Background: The Shamrock technique is a new method for ultrasound-guided lumbar plexus blockade. Data on the optimal local anaesthetic dose are not available.

Objective: The objective of this study is to estimate the effective dose of ropivacaine 0.

A quantitative assessment of glutamate uptake into hippocampal synaptic terminals and astrocytes: new insights into a neuronal role for excitatory amino acid transporter 2 (EAAT2).

The relative distribution of the excitatory amino acid transporter 2 (EAAT2) between synaptic terminals and astroglia, and the importance of EAAT2 for the uptake into terminals is still unresolved. Here we have used antibodies to glutaraldehyde-fixed d-aspartate to identify electron microscopically the sites of d-aspartate accumulation in hippocampal slices. About 3/4 of all terminals in the stratum radiatum CA1 accumulated d-aspartate-immunoreactivity by an active dihydrokainate-sensitive mechanism which was absent in EAAT2 glutamate transporter knockout mice.

Cellular distribution of a high-affinity glutamate transporter in the nervous system of the cabbage looper Trichoplusia ni.

Glutamate functions as a neurotransmitter in the central nervous system (CNS) and neuromuscular junctions in insects. High-affinity glutamate transporters are responsible for keeping the resting levels of excitatory amino acids below the synaptic activation threshold by removing them from the extracellular fluid, thereby preventing them from reaching toxic levels. Peptides representing the N- and C-terminal regions of a glutamate transporter cloned from the cabbage looper caterpillar (Trichoplusia ni) were synthesized and used to generate polyclonal antibodies.

The glutamate transporter EAAT4 in rat cerebellar Purkinje cells: a glutamate-gated chloride channel concentrated near the synapse in parts of the dendritic membrane facing astroglia.

Antibodies to an excitatory amino acid transporter (EAAT4) label a glycoprotein of approximately 65 kDa strongly in the cerebellum and weakly in the forebrain. Cross-linking of cerebellar proteins with bis(sulfosuccinimidyl) suberate before solubilization causes dimer bands of EAAT4 and both dimer and trimer bands of the other glutamate transporters GLAST (EAAT1) and GLT (EAAT2) to appear on immunoblots. In contrast to GLAST, GLT, and EAAC (EAAT3), EAAT4 is unevenly distributed in the cerebellar molecular layer, being strongly expressed in parasagittal zones.

Differential developmental expression of the two rat brain glutamate transporter proteins GLAST and GLT.

The extracellular concentration of the excitatory neurotransmitter glutamate is kept low by the action of glutamate transporters in the plasma membranes of both neurons and glial cells. These transporters may play important roles, not only in the adult brain, but also in the developing brain, as glutamate is thought to modulate the formation and elimination of synapses as well as neuronal migration, proliferation and apoptosis. Here we demonstrate the developmental changes in the expression of two glutamate transporters, GLAST and GLT, by quantitative immunoblotting and by light and electron microscopic immunocytochemistry.

Brain glutamate transporter proteins form homomultimers.

Removal of excitatory amino acids from the extracellular fluid is essential for synaptic transmission and for avoiding excitotoxicity. The removal is accomplished by glutamate transporters located in the plasma membranes of both neurons and astroglia. The uptake system consists of several different transporter proteins that are carefully regulated, indicating more refined functions than simple transmitter inactivation.

The competitive transport inhibitor L-trans-pyrrolidine-2, 4-dicarboxylate triggers excitotoxicity in rat cortical neuron-astrocyte co-cultures via glutamate release rather than uptake inhibition.

We studied the early and late effects of L-trans-pyrrolidine-2,4-dicarboxylate (PDC), a competitive inhibitor of glutamate uptake with low affinity for glutamate receptors, in co-cultures of rat cortical neurons and glia expressing spontaneous excitatory amino acid (EAA) neurotransmission. At 100 or 200 microM, PDC induced different patterns of electrical changes: 100 microM prolonged tetrodotoxin-sensitive excitation triggered by synaptic glutamate release; 200 microM produced sustained, tetrodotoxin-insensitive and EAA-mediated neuronal depolarization, overwhelming synaptic activity. At 200 microM, but not at 100 microM, PDC caused rapid elevation of the glutamate concentration ([Glu]o) in the culture medium, resulting in NMDA receptor-mediated excitotoxic death of neurons 24 h later.