Search results for " Transport"
showing 10 items of 3573 documents
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…
Characterisation of [11C]PR04.MZ in Papio anubis baboon: A selective high-affinity radioligand for quantitative imaging of the dopamine transporter
2012
N-(4-fluorobut-2-yn-1-yl)-2β-carbomethoxy-3β-(4′-tolyl)nortropane (PR04.MZ, 1) is a PET radioligand for the non-invasive exploration of the function of the cerebral dopamine transporter (DAT). A reliable automated process for routine production of the carbon-11 labelled analogue [11C]PR04.MZ ([11C]-1) has been developed using GMP compliant equipment. An adult female Papio anubis baboon was studied using a test–retest protocol with [11C]-1 in order to assess test–retest reliability, metabolism and CNS distribution profile of the tracer in non-human primates. Blood sampling was performed throughout the studies for determination of the free fraction in plasma (fP), plasma input functions and m…
Secretagogues Modulate the Calcium Concentration in the Endoplasmic Reticulum of Insulin-secreting Cells
1999
The precise regulation of the Ca2+ concentration in the endoplasmic reticulum ([Ca2+]er) is important for protein processing and signal transduction. In the pancreatic beta-cell, dysregulation of [Ca2+]er may cause impaired insulin secretion. The Ca2+-sensitive photoprotein aequorin mutated to lower its Ca2+ affinity was stably expressed in the endoplasmic reticulum (ER) of rat insulinoma INS-1 cells. The steady state [Ca2+]er was 267 +/- 9 microM. Both the Ca2+-ATPase inhibitor cyclopiazonic acid and 4-chloro-m-cresol, an activator of ryanodine receptors, caused an almost complete emptying of ER Ca2+. The inositol 1,4,5-trisphosphate generating agonists, carbachol, and ATP, reduced [Ca2+]e…
SPECT-Untersuchungen mit dem 123I-markierten Dopamintransporter-Liganden FP-CIT (DaTSCANTM)
2019
ZusammenfassungDie S1-Leitlinie soll bei der Indikationsstellung, Durchführung, Interpretation und Befundung von SPECT-Untersuchungen des Dopamintransporters (DAT) mit DaTSCANTM unterstützen. Gegenüber der Vorgängerversion von 2007 berücksichtigt die vorliegende Aktualisierung und Überarbeitung die neuere wissenschaftliche Literatur, zwischenzeitlich veröffentlichte Guidelines der europäischen (EANM) und amerikanischen Fachgesellschaften (SNM), sowie die aktuelle Fassung der S3-Leitlinie „Idiopathisches Parkinson-Syndrom“ der Deutschen Gesellschaft für Neurologie. Zudem finden neue technische Möglichkeiten Berücksichtigung.
Combined Epidural and General Anesthesia Prevents Excessive Oxygen Consumption Postoperatively
1994
In the postoperative period patients are at risk of excessive oxygen consumption (VO2). However, patients suffering from cardiovascular disease may be unable to increase their oxygen transport capacity sufficiently and may be especially vulnerable to tissue hypoxia as part of the reaction to intraoperative stress. During the last 10 years contradictory results concerning the benefits of a combined epidural and light general anesthesia have been published. Some of the results indicate that postoperative catabolism maybe depressed and that the neuroendocrine response to stress may be inhibited by such a combined technique1,2. We studied the effect of a combined epidural and light general anes…
Mitochondria as a Target for Future Diabetes Treatments
2015
Diabetes mellitus is rapidly becoming the world’s most dangerous serial killer. Type 1 diabetes (T1D) is a currently incurable autoimmune disease marked by progressive, and eventually exhaustive, destruction of the insulin-producing pancreatic beta cells. Type 2 diabetes (T2D) describes the combination of insulin resistance in peripheral tissue, insufficient insulin secretion from the pancreatic beta cells, and excessive glucagon secretion from the pancreatic alpha cells. T1D as well as severe cases of T2D are treated with insulin replacement, which can merely be considered as life support for the acute phases of the disease. Islet replacement of insulin-producing pancreatic beta cells repr…
Mitochondrial complex I impairment in leukocytes from polycystic ovary syndrome patients with insulin resistance.
2009
Insulin resistance is a feature of polycystic ovary syndrome (PCOS) and is related to mitochondrial function.Our objective was to assess mitochondrial function by evaluating mitochondrial oxygen (O(2)) consumption, reactive oxygen species (ROS) production, levels of glutathione (GSH), the oxidized glutathione/GSH ratio, TNFalpha levels, and membrane potential. Additionally, we have evaluated mitochondrial complex I as a target of the oxidative stress responsible for PCOS in polymorphonuclear cells.This was a prospective controlled study conducted in an academic medical center.The study population consisted of 20 lean reproductive-age women with PCOS and 20 body composition-matched controls.…
Glucose transporter 4 mRNA expression in subcutaneous adipose tissue of women with PCOS remains unchanged despite metformin withdrawal: is there a ce…
2021
Purpose: Metformin induces GLUT-4 mRNA expression in insulin target tissues in PCOS. It is unclear how long this impact is sustained after withdrawal of metformin. We aimed to compare the effect of metformin withdrawal on GLUT-4 mRNA expression in subcutaneous adipose tissue after prior short (ST, 1 year, N = 11) and long term (LT, at least 3 years, N = 13) treatment in obese PCOS women. Methods: At baseline and 6 months after withdrawal, biopsy of subcutaneous adipose tissue followed by quantitative PCR analysis was performed to determine GLUT-4 mRNA expression. Results: We found no time/effect differences in GLUT-4 mRNA expression in ST (2-dCt at baseline 0.42 (0.16–0.48) vs 2-dCt after 6…
Regulated Proteolysis of RAGE and AβPP as Possible Link Between Type 2 Diabetes Mellitus and Alzheimer's Disease
2009
Epidemiological studies have linked type 2 diabetes mellitus (T2DM) with an increased risk of developing Alzheimer's disease (AD). In T2DM, the elevated blood glucose level promotes formation of advanced glycation end products (AGEs). The receptor for AGEs (RAGE) is a type I membrane-protein and is also able to import amyloid-beta (Abeta) from the blood across the blood-brain-barrier into the brain. Oligomeric Abeta peptides disturb synaptic function in the brain and are believed to contribute to the development of AD. Abeta peptides are released from the amyloid-beta protein precursor (AbetaPP) after sequential proteolysis by beta- and gamma-secretases but alpha-secretase-mediated cleavage…
Control of Gastric Acid Secretion in Somatostatin Receptor 2 Deficient Mice: Shift from Endocrine/Paracrine to Neurocrine Pathways
2007
The gastrin-enterochromaffin-like (ECL) cell-parietal cell axis is known to play an important role in the regulation of gastric acid secretion. Somatostatin, acting on somatostatin receptor type 2 (SSTR2), interferes with this axis by suppressing the activity of the gastrin cells, ECL cells, and parietal cells. Surprisingly, however, freely fed SSTR2 knockout mice seem to display normal circulating gastrin concentration and unchanged acid output. In the present study, we compared the control of acid secretion in these mutant mice with that in wild-type mice. In SSTR2 knockout mice, the number of gastrin cells was unchanged; whereas the numbers of somatostatin cells were reduced in the antru…