Search results for "Neural"
showing 10 items of 2783 documents
Hypokalemia shortens relative refractory period of peripheral sensory nerves in man
1977
Absolute and relative refractory periods and the sensory conduction velocity of the median and ulnar nerves were determined in six patients suffering from hypokalemia of various origins. Nerve impulse conduction and the absolute refractory period remained normal, but the relative refractory period was shortened to 1.7 to 2.6 ms at serum K+ levels from 1.6 to 2.9 mval/l. As compared with normal values this decrease was statistically significant.
Imaging of inner ear malformations: a primer for radiologists
2021
AbstractIn the multidisciplinary management of patients with inner ear malformations (IEMs), the correct diagnosis makes the differences in terms of clinical and surgical treatment. The complex anatomical landscape of the inner ear, comprising several small structures, makes imaging of this region particularly challenging for general radiologists. Imaging techniques are important for identifying the presence and defining the type of IEM and the cochlear nerve condition. High-resolution magnetic resonance imaging (MRI) sequences and high-resolution computed tomography (HRCT) are the mainstay imaging techniques in this area. Dedicated MRI and HRCT protocols play an important role in the diagn…
Neurally adjusted ventilatory assist: An update
2014
Summary Neurally adjusted ventilatory assist (NAVA) is a new ventilation mode that provides a proportional assistance to the inspiratory effort of the patients. It is based on the use of the diaphragm electromyographic activity (Edi) for the control of the ventilation assistance. The ability of NAVA to improve the limitations of the conventional assisted ventilator modes has been assessed in clinical studies and discussed in this report, as the latest applications of NAVA in children and non-invasive ventilation, due to the improvement of the patient–ventilator interactions delivered by NAVA. We also review the most recent literature on a new trend to use the Edi as a predictor of weaning s…
Cortical and subcortical visual event-related potentials to oddball stimuli in rabbits
2000
We applied repetitive transcranial magnetic stimulation (rTMS) in order to induce interference on visuo-spatial perception in 11 healthy subjects. Subjects performed a visuo-spatial task requiring judgements about the symmetry of prebisected lines. Visual stimuli consisted of symmetrically or asymmetrically transected lines, tachystoscopically presented for 50 ms on a computer-monitor. Performance was examined in basal condition and during rTMS trains of 10 stimuli at 25 Hz, delivered through a focal coil over right or left posterior parietal cortex (P5 and P6 sites) and triggered synchronously with visual stimulus. Randomly intermixed sham rTMS trains were employed to control for non-speci…
Intrinsic activation of GABAA receptors suppresses epileptiform activity in the cerebral cortex of immature mice
2010
SUMMARY Purpose: Activation of ionotropic c-aminobutyric acid type A (GABAA) receptors induces in immature neocortical neurons a membrane depolarization that may contribute to the higher epilepsy susceptibility in newborns. To elucidate whether depolarizing GABAergic responses enhance or attenuate epileptiform activity in the immature neocortex, we investigated the effect of agonists, antagonists, and positive modulators of GABAA receptors on epileptiform activity. Methods: We performed in vitro field potential recordings on isolated whole neocortex preparations and whole cell recordings of identified pyramidal neurons in 400-lm slices of immature (postnatal day 1–7) mice. Epileptiform acti…
Behavioural responsiveness to picrotoxin and desipramine in adult rats prenatally exposed to different benzodiazepine receptor agonists
1995
The behavioural responsiveness to picrotoxin and desipramine was investigated in adult rats prenatally exposed to different benzodiazepine receptor agonists such as diazepam, alprazolam and zolpidem. Prenatal exposure to diazepam and alprazolam similarly potentiated the anti-immobility effect on the forced swimming test and the inhibitory effect on spontaneous motor activity of picrotoxin and desipramine and increased the seizure sensitivity to picrotoxin. Prenatal zolpidem seems to be ineffective. These data suggest that, despite the differences in their pharmacodynamic profile, prenatal exposure to diazepam and alprazolam, but not zolpidem, may have similar permanent consequences on the b…
Signaling through BMPR-IA regulates quiescence and long-term activity of neural stem cells in the adult hippocampus.
2010
SummaryNeural stem cells (NSCs) in the adult hippocampus divide infrequently, and the molecules that modulate their quiescence are largely unknown. Here, we show that bone morphogenetic protein (BMP) signaling is active in hippocampal NSCs, downstream of BMPR-IA. BMPs reversibly diminish proliferation of cultured NSCs while maintaining their undifferentiated state. In vivo, acute blockade of BMP signaling in the hippocampus by intracerebral infusion of Noggin first recruits quiescent NSCs into the cycle and increases neurogenesis; subsequently, it leads to decreased stem cell division and depletion of precursors and newborn neurons. Consistently, selective ablation of Bmpr1a in hippocampal …
Regulation by oestrogens of tachykinin NK3 receptor expression in the rat uterus.
1997
The expression of the tachykinin NK3 receptor and its regulation by ovarian steroids were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) in uteri from ovariectomized rats. A single transcript corresponding to the 325-bp product expected for the tachykinin NK3 receptor was detected in uteri from olive oil-treated (control) ovariectomized rats. The level of tachykinin NK3 receptor mRNA in progesterone-treated animals was similar to that observed in uteri from control ones. Tachykinin NK3 receptor mRNA levels were significantly smaller in uteri from oestrogen-treated ovariectomized rats, with approximately a 32-fold decrease. These findings suggest that oestrogen, but not…
Abnormal development of pacinian corpuscles in double trkB;trkC knockout mice.
2006
Pacinian corpuscles depend on either Aalpha or Abeta nerve fibers of the large- and intermediate-sized sensory neurons for the development and maintenance of the structural integrity. These neurons express TrkB and TrkC, two members of the family of signal transducing neurotrophin receptors, and mice lacking TrkB and TrkC lost specific neurons and the sensory corpuscles connected to them. The impact of single or double targeted mutations in trkB and trkC genes in the development of Pacinian corpuscles was investigated in 25-day-old mice using immunohistochemistry and ultrastructural techniques. Single mutations on trkB or trkC genes were without effect on the structure and S100 protein expr…
The "Tokyo" consensus on propeller flaps
2011
Background: Overthepastfewyears,theuseofpropellerflaps,whichbasetheir blood supply on subcutaneous tissue or isolated perforators, has become in- creasingly popular. Because no consensus has yet been reached on terminology and nomenclature of the propeller flap, different and confusing uses of the term can be found in the literature. Methods: Inthisarticle,theauthorsreporttheconsensusonthedefinitionand classification of propeller flaps reached by the authors that gathered at the First Tokyo Meeting on Perforator and Propeller Flaps in June of 2009. Some peculiar aspects of the surgical technique are discussed. Results: A propeller flap can be defined as an “island flap that reaches the reci…