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PubMed | Medical University of Innsbruck and Hospital Kufstein
Type: Case Reports | Journal: Journal of neurosurgery. Spine | Year: 2016

A 33-year-old man presented with moderate low-back pain and L-5 radiculopathy that progressed to severe paresis of L-5. On initial imaging, a corresponding spinal lesion was overlooked. Further CT and contrast-enhanced MRI demonstrated a presacral mass along the L-5 root far extraforaminally. A herniated disc was suspected, but with standard imaging a schwannoma could not be ruled out. The presacral L-5 root was explored via a microsurgical lateral extraforaminal transmuscular approach. To the best of the authors knowledge, there have been no reports of sequestered extraforaminal lumbosacral disc herniations that herniated into the presacral region.

News Article | February 15, 2017
Site: www.sciencemag.org

Between 1990 and 2013, thousands of children in war-torn South Sudan and northern Uganda suddenly developed a severe and puzzling form of epilepsy. When exposed to food or cold temperatures, affected children nodded their heads uncontrollably. Over time the seizures often worsened, leaving the children severely disabled. Many died of malnutrition, accidents, or secondary infections. In some communities, roughly half of families had at least one child with the condition, called nodding syndrome; by 2013, an estimated 1600 children in Uganda were affected. But the cause of the devastation was a mystery. Now, a study finds that a parasitic worm often found in the children might trigger the body’s own defenses to attack neurons. The study doesn’t prove the worm is the culprit, but it “is the first to show that a cause-effect relationship is plausible,” says Hermann Feldmeier, a parasitologist at the Charité University Hospital in Berlin, who was not involved in the study. The rash of cases in Uganda and South Sudan triggered an intense hunt for the cause, but searches for viruses, bacteria, environmental toxins, genetic factors, and nutritional deficits all came up empty. One key clue: Areas with nodding syndrome also had high rates of onchocerciasis, an infection with the parasitic worm Onchocerca volvulus. Spread through the bites of black flies, which breed in swift-flowing streams, the worms can invade the eye, and the infection is commonly known as river blindness. The World Health Organization estimates that at least 18 million people, most in sub-Saharan Africa, are infected. Researchers had suggested as early as the 1960s that high rates of epilepsy in Tanzania, with similar nodding symptoms, might be related to onchocerciasis. Others have noted that children with nodding syndrome are more likely to be infected than their healthy peers. But there’s no evidence that the worm invades the brain or directly causes seizures. Some researchers suggested that the worm instead causes an autoimmune reaction that damages the nervous system. Searches for antibodies that might play an autoimmune role had come up empty. But neuroimmunologists Avindra Nath and Tory Johnson of the National Institutes of Health in Bethesda, Maryland, decided to use an improved protein chip to screen for antibodies to thousands of proteins at once. The new tool proved its worth. Blood from nodding syndrome patients reacted strongly to four proteins; in the case of one protein, called leiomodin-1, patient sera reacted 33,000 times more strongly than did sera from unaffected controls. The researchers then looked for the antibodies causing the reaction. As they report this week in , antibodies to leiomodin-1 turned up in 29 of 55 nodding syndrome patients but only 17 of 55 controls. Patients also carried much higher antibody levels than controls. Leiomodin-1, which likely plays a role in cell shape, is found in smooth muscle and thyroid cells. Johnson’s team showed that it is expressed in the nervous system and brain, too. They also found a clue to what might trigger an autoimmune reaction to the protein: Several O. volvulus proteins resemble it. After the immune system gears up to fight the worm, similarities between an O. volvulus protein and leiomodin-1 may cause the antibodies to mistakenly attack neurons. The study gives little hope to children already affected, Nath says. Although antiseizure drugs can help, if the immune system has attacked neurons, the damage is likely permanent. However, the work could suggest a straightforward way to eliminate the disease, says infectious disease specialist Robert Colebunders of the University of Antwerp in Belgium, because the drug ivermectin kills the worm. Existing campaigns to eliminate river blindness by giving the drug could have a collateral benefit: After the Ugandan government stepped up ivermectin treatment, new cases of nodding syndrome plunged to nearly zero, Colebunders says. “If you eliminate the onchocerciasis, the epilepsy really disappears.” Yet the link between the worm and nodding syndrome doesn’t explain why the illness suddenly appeared in a region where onchocerciasis has likely been common for centuries, or why nodding syndrome only affects children and youth. Johnson, now at Johns Hopkins University in Baltimore, Maryland, says malnutrition, exposure to other diseases, or genetic variation in how the body makes antibodies may also play a role. Other researchers have suggested that measles infection followed by malnutrition could trigger the disease. Neurologist Erich Schmutzhard of the Medical University of Innsbruck in Austria has other doubts. He says that the leiomodin-1 antibodies could be a result of epilepsy, not its cause. The protein seems to be on the inside of neurons, not the outside, he notes. Seizures kill neurons, and he speculates that dying neurons could spill the protein into the blood stream, triggering the antibodies. The onchocerciasis connection is intriguing but far from definitive, says neurologist Andrea Winkler of the Technical University of Munich in Germany. She, too, thinks the syndrome is likely caused by multiple factors, such as malnutrition, parasites, and viruses like measles. “There are still lots of links missing.”

PubMed | University of Tübingen, Medical University of Innsbruck and Innsbruck Medical University
Type: | Journal: Journal of visualized experiments : JoVE | Year: 2016

Freeze-fracture electron microscopy has been a major technique in ultrastructural research for over 40 years. However, the lack of effective means to study the molecular composition of membranes produced a significant decline in its use. Recently, there has been a major revival in freeze-fracture electron microscopy thanks to the development of effective ways to reveal integral membrane proteins by immunogold labeling. One of these methods is known as detergent-solubilized Freeze-fracture Replica Immunolabeling (FRIL). The combination of the FRIL technique with optogenetics allows a correlated analysis of the structural and functional properties of central synapses. Using this approach it is possible to identify and characterize both pre- and postsynaptic neurons by their respective expression of a tagged channelrhodopsin and specific molecular markers. The distinctive appearance of the postsynaptic membrane specialization of glutamatergic synapses further allows, upon labeling of ionotropic glutamate receptors, to quantify and analyze the intrasynaptic distribution of these receptors. Here, we give a step-by-step description of the procedures required to prepare paired replicas and how to immunolabel them. We will also discuss the caveats and limitations of the FRIL technique, in particular those associated with potential sampling biases. The high reproducibility and versatility of the FRIL technique, when combined with optogenetics, offers a very powerful approach for the characterization of different aspects of synaptic transmission at identified neuronal microcircuits in the brain. Here, we provide an example how this approach was used to gain insights into structure-function relationships of excitatory synapses at neurons of the intercalated cell masses of the mouse amygdala. In particular, we have investigated the expression of ionotropic glutamate receptors at identified inputs originated from the thalamic posterior intralaminar and medial geniculate nuclei. These synapses were shown to relay sensory information relevant for fear learning and to undergo plastic changes upon fear conditioning.

PubMed | Innsbruck Medical University and Medical University of Innsbruck
Type: | Journal: Journal of visualized experiments : JoVE | Year: 2017

Dendritic cells (DCs) recognize foreign structures of different pathogens, such as viruses, bacteria, and fungi, via a variety of pattern recognition receptors (PRRs) expressed on their cell surface and thereby activate and regulate immunity. The major function of DCs is the induction of adaptive immunity in the lymph nodes by presenting antigens via MHC I and MHC II molecules to nave T lymphocytes. Therefore, DCs have to migrate from the periphery to the lymph nodes after the recognition of pathogens at the sites of infection. For in vitro experiments or DC vaccination strategies, monocyte-derived DCs are routinely used. These cells show similarities in physiology, morphology, and function to conventional myeloid dendritic cells. They are generated by interleukin 4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulation of monocytes isolated from healthy donors. Here, we demonstrate how monocytes are isolated and stimulated from anti-coagulated human blood after peripheral blood mononuclear cell (PBMC) enrichment by density gradient centrifugation. Human monocytes are differentiated into immature DCs and are ready for experimental procedures in a non-clinical setting after 5 days of incubation.

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