Pairing transition metals and heavier tetrylenes (Si, Ge, Sn, Pb) holds great potential for cooperative bond activation and catalysis. In this work, we investigate the reactivity of a low-coordinate Pt(0)/Ge(II) system that emerges from the reaction between the monoligated platinum(0) precursor [(PMeAr)Pt(olefin)] with germylene dimer [ArGeCl] (where Ar = CH-2,6-(CH-2,6-Pr)). The resulting complex reveals ability for cooperative bond activation.
View Article and Find Full Text PDFBalance disorders are highly prevalent worldwide, causing substantial disability with high personal and socioeconomic impact. The prognosis in many of these patients is poor, and rehabilitation programs provide little help in many cases. This medical problem can be addressed using microelectronics by combining the highly successful cochlear implant experience to produce a vestibular prosthesis, using the technical advances in micro gyroscopes and micro accelerometers, which are the electronic equivalents of the semicircular canals (SCC) and the otolithic organs.
View Article and Find Full Text PDFGalvanic vestibular stimulation (GVS) helps stabilize subjects when balance and posture are compromised. This work aimed to define the cortical regions that GVS activates in normal subjects. We used functional near-infrared spectroscopy (fNIRS) to test the hypothesis that GVS activates similar cortical areas as a passive movement.
View Article and Find Full Text PDFPrevious works showed that opioid peptides are produced by olivocochlear efferent neurons, while cochlear hair cells express opioid receptors. It has been proposed that opioids protect the auditory system from damage by intense stimulation, although their use for therapeutic or illicit purposes links to hearing impairment. Therefore, it is relevant to study the effect of opioids in the auditory system to define their functional expression and mechanism of action.
View Article and Find Full Text PDFThe study of cardiovascular function with galvanic vestibular stimulation has provided evidence on the neural structures that are involved in the vestibulo-autonomic reflex. This study determined if the effect on heart rate using galvanic vestibular stimulation persists after provoking a sympathetic response and if this response differs when using unilateral or transmastoid (bilateral) stimulation. We analysed heart rate and heart rate variability using unilateral and transmastoid galvanic vestibular stimulation combined with cardiovascular reflex evoked by postural change in 24 healthy human subjects.
View Article and Find Full Text PDFThe vestibular system is modulated by various neuromodulators including opioid peptides. The current study was conducted to determine whether activation of nociceptin/orphanin FQ peptide (NOP) receptors modulates voltage-gated calcium currents and action potential discharge of rat vestibular afferent neurons. We performed whole cell patch-clamp recordings on cultured vestibular afferent neurons from P7-P10 Long-Evans rats.
View Article and Find Full Text PDFIn this work, we evaluate the effect of two peptides Sa12b (EDVDHVFLRF) and Sh5b (DVDHVFLRF-NH) on Acid-Sensing Ion Channels (ASIC). These peptides were purified from the venom of solitary wasps and , respectively. Voltage clamp recordings of ASIC currents were performed in whole cell configuration in primary culture of dorsal root ganglion (DRG) neurons from (P7-P10) CII Long-Evans rats.
View Article and Find Full Text PDFThe auditory system has an extensive efferent innervation, which contributes to processes of control and regulation of the afferent input. The expression of receptors to various neurotransmitters and neuropeptides in the inner ear has been described, among which endogenous opioid receptors are found. The role of opioid receptors in the cochlea is not yet fully defined, it has been reported that opioid agonists and antagonists modulate the response to auditory stimuli and in clinical practice, multiple cases have been reported in which the consumption of opioid derivatives induce sensorineural hearing loss.
View Article and Find Full Text PDFFront Cell Neurosci
October 2018
In this review, evidence demonstrating that protons (H) constitute a complex, regulated intercellular signaling mechanisms are presented. Given that pH is a strictly regulated variable in multicellular organisms, localized extracellular pH changes may constitute significant signals of cellular processes that occur in a cell or a group of cells. Several studies have demonstrated that the low pH of synaptic vesicles implies that neurotransmitter release is always accompanied by the co-release of H into the synaptic cleft, leading to transient extracellular pH shifts.
View Article and Find Full Text PDFMultiple sclerosis (MS) is a high prevalence degenerative disease characterized at the cellular level by glial and neuronal cell death. The causes of cell death during the disease course are not fully understood. In this work we demonstrate that in a MS model induced by Theiler's murine encephalomyelitis virus (TMEV) infection, the inward rectifier (Kir) 4.
View Article and Find Full Text PDFSea anemones produce proteinaceous toxins for predation and defense, including peptide toxins that act on a large variety of ion channels of pharmacological and biomedical interest. is commonly found in the Caribbean Sea; however, the chemical structure and biological activity of its toxins remain unknown, with the exception of PhcrTx1, an acid-sensing ion channel (ASIC) inhibitor. Therefore, in the present work, we focused on the isolation and characterization of new toxins by chromatographic fractionation, followed by a toxicity screening on crabs, an evaluation of ion channels, and sequence analysis.
View Article and Find Full Text PDFAcid-sensing ion channels (ASICs) are a family of proton-sensing channels that are voltage insensitive, cation selective (mostly permeable to Na), and nonspecifically blocked by amiloride. Derived from 5 genes (), 7 subunits have been identified, 1a, 1b, 2a, 2b, 3, 4, and 5, that are widely expressed in the peripheral and central nervous system as well as other tissues. Over the years, different studies have shown that activation of these channels is linked to various physiological and pathological processes, such as memory, learning, fear, anxiety, ischemia, and multiple sclerosis to name a few, so their potential as therapeutic targets is increasing.
View Article and Find Full Text PDFCytotoxicity of titanium dioxide (TiO₂) thin films on Chinese hamster ovary (CHO-K1) cells was evaluated after 24, 48 and 72 h of culture. The TiO₂ thin films were deposited using direct current magnetron sputtering. These films were post-deposition annealed at different temperatures (300, 500 and 800 °C) toward the anatase to rutile phase transformation.
View Article and Find Full Text PDFObjective: To determine whether the use of the robot for surgical treatment of endometriosis is better than traditional laparoscopy in terms of operative length, perioperative parameters, and quality of life outcomes.
Design: Multicenter, randomized clinical trial.
Setting: University teaching hospitals.
We previously reported a multigene family of monodomain Kunitz proteins from Echinococcus granulosus (EgKU-1-EgKU-8), and provided evidence that some EgKUs are secreted by larval worms to the host interface. In addition, functional studies and homology modeling suggested that, similar to monodomain Kunitz families present in animal venoms, the E. granulosus family could include peptidase inhibitors as well as channel blockers.
View Article and Find Full Text PDF. To compare long-term fertility and bleeding outcomes of women who underwent robotic-assisted, laparoscopic, and abdominal myomectomy at our institution over a 15-year period. .
View Article and Find Full Text PDFExtended-spectrum beta-lactamase-producing Enterobacteriaceae have increasingly become a public health issue in a variety of infections, including urinary tract infections and postoperative infections. The complications that occur due to these organisms in bone, joint, and prosthetic joints have not been well defined. This study reviewed the clinical characteristics, risk factors, and outcomes of patients with extended-spectrum beta-lactamase-producing Enterobacteriaceae infections of prosthetic joints or orthopedic-related hardware.
View Article and Find Full Text PDFStudy Objective: To assess long-term bowel symptoms in women who underwent segmental bowel resection for deep-infiltrating endometriosis (DIE) compared with women who underwent resection of severe endometriosis without bowel resection.
Design: Cohort study with matched controls (Canadian Task Force classification II-2).
Setting: Cleveland Clinic.
A novel conotoxin, named as PiVIIA, was isolated from the venom of Conus princeps, a marine predatory cone snail collected in the Pacific Southern Coast of Mexico. Chymotryptic digest of the S-alkylated peptide in combination with liquid chromatography coupled to tandem mass spectrometry, were used to define the sequencing of this peptide. Eleven N-terminal amino acids were verified by automated Edman degradation.
View Article and Find Full Text PDFAcid-sensing ion channels (ASICs) are activated by an increase in the extracellular proton concentration. There are four genes (ASIC1-4) that encode six subunits, and they are involved in diverse neuronal functions, such as mechanosensation, learning and memory, nociception, and modulation of retinal function. In this study, we characterize the ASIC currents of spiral ganglion neurons (SGNs).
View Article and Find Full Text PDFDendrotoxins are a group of peptide toxins purified from the venom of several mamba snakes. α-Dendrotoxin (α-DTx, from the Eastern green mamba Dendroaspis angusticeps) is a well-known blocker of voltage-gated K(+) channels and specifically of K(v)1.1, K(v)1.
View Article and Find Full Text PDFObjectives: Advances in laparoscopy have demonstrated that supraumbilical primary ports can be desirable in complex cases with large masses. This study evaluated distances to vital retroperitoneal vasculature that were encountered with 45- and 90-degree angle entry from the umbilicus and 2 commonly described supraumbilical entry points at 3 and 5 cm cephalad from the umbilicus.
Study Design: Retrospective analysis of computed tomography scans of the abdomen and pelvis from 100 randomly selected women who were 18-50 years old with normal anatomy was performed.