Objective: To investigate the effects of hyperglycemia on persistent Na+ currents in human diabetic nerves, eliminating the factors of passive membrane properties as a factor. Previous studies show that strength-duration time constant of a nerve is shortened under hyperglycemia, suggesting reduced axonal persistent Na+ currents. However, the time constant is also affected by changes in passive membrane properties. Latent addition using computerized threshold tracking is a new method that can separately evaluate Na+ currents and passive membrane properties.
Methods: Latent addition was used to estimate nodal Na+ currents in median motor axons of 83 diabetic patients. Brief hyperpolarizing conditioning current pulses were delivered, and threshold changes at the conditioning-test interval of 0.2 ms were measured as an indicator of nodal persistent Na+ currents. Seventeen patients were examined before and after insulin treatment.
Results: There was an inverse linear relationship between hemoglobin A1c levels and threshold changes at 0.2 ms (P=0.02); the higher hemoglobin A1c levels were associated with smaller threshold changes. After insulin treatment, there was a significant improvement in nerve conduction velocities associated with greater threshold changes at 0.2 ms (P=0.03), suggesting an increase in persistent Na+ currents. The fast component of latent addition, an indicator of passive membrane properties, was not affected by the state of glycemic control.
Conclusions: Hyperglycemia could suppress nodal persistent Na+ currents, presumably because of reduced trans-axonal Na+ gradient or impaired Na+ channels, and this can be rapidly restored by glycemic control.
Significance: Reduced nodal Na+ currents may partly contribute to the pathophysiology of human diabetic neuropathy.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.clinph.2005.11.019 | DOI Listing |
Background: In the Netherlands, it is possible for patients to donate organs after having received euthanasia. In many cases of organ donation after euthanasia (ODE), tissues, as well as the liver, heart, kidneys, lungs, and pancreas, can be donated. The procedure for ODE is described in the national guideline for organ donation after euthanasia by the Dutch Transplant Foundation (NTS).
View Article and Find Full Text PDFQuant Imaging Med Surg
January 2025
Department of Diagnostic Radiology, First Medical Center of the Chinese PLA General Hospital, Beijing, China.
Background: Traditional freehand puncture relies on non-real-time computed tomography (CT) images, which significantly affects the accuracy of puncturing targets in the lower lung lobes with respiratory motion. This study aims to assess the safety and feasibility of a teleoperated robotic system and low-dose CT for the accurate real-time puncture of targets in the lungs of live pigs during breathing under fluoroscopic guidance.
Methods: Two puncture methods were analyzed: freehand and robot-assisted.
Ann Clin Transl Neurol
January 2025
Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
Objective: Interpretation of clinical genetic testing, which identifies a potential genetic etiology in 25% of children with epilepsy, is limited by variants of uncertain significance. Understanding functional consequences of variants can help distinguish pathogenic from benign alleles. We combined automated patch clamp recording with neurophysiological simulations to discern genotype-function-phenotype correlations in a real-world cohort of children with SCN1A-associated epilepsy.
View Article and Find Full Text PDFMol Cell Pediatr
January 2025
Division of Metabolism and Children`s Research Center, University Children's Hospital Zurich, Lenggstr. 30, 8008, Zurich, Switzerland.
Background: Cerebral creatine deficiency disorders (CCDD) are rare diseases caused by defects in the enzymes L-arginine: glycine amidinotransferase (AGAT) or guanidinoacetate-N-methyltransferase (GAMT), which are involved in synthesis of creatine; or by a defect in the creatine transporter (CRTR), which is essential for uptake of creatine as important energy source into the target cells. Patients with CCDD can present with a variety of unspecific symptoms: global developmental delay, speech-language disorder, behavioral abnormalities and seizures. Early treatment initiation is essential in AGAT and GAMT deficiencies to achieve a favorable outcome.
View Article and Find Full Text PDFSci Rep
January 2025
Nanomaterials Science Research Laboratory, Chemistry Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt.
The design and fabrication of novel electrodes with strong electrochemical responses are crucial in advanced supercapacitor technology. In this study, a poly(m-toluidine)/silver-silver oxide (PMT/Ag-AgO) nanocomposite was prepared using the photopolymerization method. Various characterization techniques were employed to analyze the prepared nanomaterials.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!