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Bianca Jagger
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Bianca Jagger is a prominent human rights defender. For over three decades she has been a voice for the most vulnerable members of society, campaigning for human rights, civil liberties, peace, social justice and environmental protection throughout the world. All comments made here are Bianca Jagger's personal views.
Bianca Jagger is a prominent human rights defender. For over three decades she has been a voice for the most vulnerable members of society, campaigning for human rights, civil liberties, peace, social justice and environmental protection throughout the world. All comments made here are Bianca Jagger's personal views.

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Cuál es el legado del represivo régimen #OrtegaMurillo en #Nicaragua: lograron desmantelar las instituciones legales, controlar el poder legislativo, judicial y electoral y lograron destruir la oposición política en el pais. Pero afortunadamente no lograron subyugar a los valientes campesinos, estudiantes, periodistas independientes y a los respetados lideres de la Iglesia Católica... Ponga atención Sr #Ortega, no nos subestime, recuérdese de lo que ocurrió en 1978

Cuál es el legado del represivo régimen #OrtegaMurillo en #Nicaragua: lograron desmantelar las instituciones legales, controlar el poder legislativo, judicial y electoral y lograron destruir la oposición política en el pais. Pero afortunadamente no lograron subyugar a los valientes campesinos, estudiantes, periodistas independientes y a los respetados lideres de la Iglesia Católica... Ponga atención Sr #Ortega, no nos subestime, recuérdese de lo que ocurrió en 1978

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‪La única solución pacífica para #Nicaragua es que el régimen #OrtegaMurillo deje el poder, y que se llamen a #EleccionesLibres #SOSNicaragua RT #Ortega tiene que irse del poder https://www.laprensa.com.ni/2018/04/23/editorial/2408520-ortega-tiene-que-irse-del-poder via @laprensa‬

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ALERT: Navigation System of Brain Cells Decoded. The human brain contains roughly 100 billions neurons. information among them is transmitted via a complex network of nerve fibres. Hardwiring of most of this network takes place before birth according to a genetic.
Navigation System of Brain Cells Decoded
The human brain contains roughly 100 billion neurons. Information among them is transmitted via a complex network of nerve fibers. Hardwiring of most of this network takes place before birth according to a genetic blueprint, that is without external influences playing a role. Researchers of Karlsruhe Institute of Technology (KIT) have now found out more about how the navigation system guiding the axons during growth works.

Total length of the nerve fiber network in the brain is approximately 500,000 km, more than the distance between the earth and the moon. Growth of the nerve fibers is controlled by a navigation system to prevent incorrect hardwiring. But how exactly do the nerve fibers find their target region during growth? “This is similar to autonomous driving in road traffic,” says Franco Weth of the Cell and Neural Biology Division of the Zoological Institute.

Vehicles exchange information with each other and with signal transmitters at the roadside to reach their destination. In case of nerve fibers, sensor molecules at their ends serve as antennas. With them, they receive guiding signals in the form of proteins that are positioned along the way, in the target area, and on other fibers crossing the path. Having arrived at the target, axons form interconnections with other neurons, the synapses.

An example of such hardwiring is the connection between retina and brain, Weth says. Nearly one million nerve fibers reach the visual regions via the visual nerve. Genetically pre-programmed “neural hardwiring” causes the pixels to be reproduced one-to-one similar to a projection and, thus, enables a newborn child to see and process an image. This vital capability has developed by evolution of our species and does not have to be acquired by own experience. “Only few synapses of our brain are hardwired by learning,” Weth points out.

Surprisingly, the axons’ sensitivity to incoming signals of their protein navigation system decreases during the travel. “Still, information has to be read out precisely for the axons to find their target,” Weth and his colleagues wondered. The solution: “The axons indeed are desensitized for all types of signals guiding them, but they surprisingly preserve the ratio of signal strengths to each other,” Weth says. In the end, the target is characterized by a certain ratio of several signals rather than by the intensity of a single signal.

Thanks to this refined coupling of sensitivities, the axonal navigation system manages the conflict between reliability and variability of signals. This type of coupled signal regulation is highly unusual in biology. “Although you quickly cease to notice the smell of the perfume of the person opposite you, this does not mean that you no longer smell the coffee you are drinking at the moment. But this is what happens in the brain.”

Researchers do not yet know why navigation of the axons is desensitized contrary to the naïve expectation that a strong signal will most certainly guide them to their target. “We presume that it is a strategy to save energy, because signal transmission needs energy,” Weth says. Actually, nature is striving for disorder.” Establishing order consumes energy. This is something we know. Nothing in biology is more ordered than the hardwiring of our brain. Only when nature minimizes hardwiring expenditure, can it achieve the top performance required to equip us with this ‘cognition computer’.”

With their findings, the researchers also contribute to better understanding diseases caused by hardwiring errors prior to birth. Among these diseases are the Tourette syndrome, autism, or schizophrenia.

Source:
https://www.kit.edu/kit/english/pi_2017_106_navigation-system-of-brain-cells-decoded.php

Image: Embryonal brain development: Axons (green) of retina neurons read biochemical signals by means of a growth cone (magenta) equipped with molecular antennas and guide them to targets to interconnect the visual system of the brain. Credit: KIT, Weth

#navigation #braincells #nervefibers #axons #neuroscience
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Is Alzheimer’s Disease Disorder of Energy Metabolism? New study shines new light. A team of investigators from McLean Hospital and Harvard Medical School, lead by Kai C.Sontag, MD, PhD, and Bruce M. Cohen, MD, PhD, has found a connection between
Is Alzheimer’s Disease a Disorder of Energy Metabolism? New Study Shines New Light
A team of investigators from McLean Hospital and Harvard Medical School, led by Kai C. Sonntag, MD, PhD, and Bruce M. Cohen, MD, PhD, has found a connection between disrupted energy production and the development of late-onset Alzheimer’s disease (LOAD).

“These findings have several implications for understanding and developing potential therapeutic intervention in LOAD,” explained Sonntag, an associate stem cell researcher at McLean Hospital and an assistant professor of psychiatry at Harvard Medical School. “Our results support the hypothesis that impairment in multiple interacting components of bioenergetics metabolism may be a key mechanism underlying and contributing to the risk and pathophysiology of this devastating illness.”

For three decades, it has been thought that the accumulation of small toxic molecules in the brain, called amyloid beta, or in short, Aβ, is central to the development of Alzheimer’s disease (AD). Strong evidence came from studying familial or early-onset forms of AD (EOAD) that affect about five percent of AD patients and have associations with mutations leading to abnormally high levels or abnormal processing of Aβ in the brain. However, the “Aβ hypothesis” has been insufficient to explain the pathological changes in the more common LOAD, which affects more than 5 million seniors in the United States.

“Because late-onset Alzheimer’s is a disease of age, many physiologic changes with age may contribute to risk for the disease, including changes in bioenergetics and metabolism,” said Cohen, director of the Program for Neuropsychiatric Research at McLean Hospital and the Robertson-Steele Professor of Psychiatry at Harvard Medical School. “Bioenergetics is the production, usage, and exchange of energy within and between cells or organs, and the environment. It has long been known that bioenergetic changes occur with aging and affect the whole body, but more so the brain, with its high need for energy.”

According to Sonntag and Cohen, it has been less clear what changes in bioenergetics are underlying and which are a consequence of aging and illness.

In their study, Sonntag and Cohen analyzed the bioenergetic profiles of skin fibroblasts from LOAD patients and healthy controls, as a function of age and disease. The scientists looked at the two main components that produce energy in cells: glycolysis, which is the mechanism to convert glucose into fuel molecules for consumption by mitochondria, and burning of these fuels in the mitochondria, which use oxygen in a process called oxidative phosphorylation or mitochondrial respiration.

The investigators found that LOAD cells exhibited impaired mitochondrial metabolism, with a reduction in molecules that are important in energy production, including nicotinamide adenine dinucleotide (NAD). LOAD fibroblasts also demonstrated a shift in energy production to glycolysis, despite an inability to increase glucose uptake in response to the insulin analog IGF-1. Both the abnormal mitochondrial metabolism and the increase of glycolysis in LOAD cells were disease- and not age-specific, while diminished glucose uptake and the inability to respond to IGF-1 was a feature of both age and disease.

“The observation that LOAD fibroblasts had a deficiency in the mitochondrial metabolic potential and an increase in the glycolytic activity to maintain energy supply is indicative of failing mitochondria and fits with current knowledge that aging cells increasingly suffer from oxidative stress that impairs their mitochondrial energy production,” said Sonntag.

Cohen added that because the brain’s nerve cells rely almost entirely on mitochondria-derived energy, failure of mitochondrial function, while seen throughout the body, might be particularly detrimental in the brain.

The study’s results link to findings from other studies that decreasing energy-related molecules (and specifically NAD) are features of normal aging by suggesting that abnormalities in processes involving these molecules may also be a factor in neurodegenerative diseases like LOAD. Whether modulating these compounds could slow the aging process and prevent or delay the onset of LOAD is unknown. However, several clinical trials are currently under way to test this possibility. Other changes are unique to AD, and these, too, may be targets for intervention.

While these findings are significant, the paper’s authors emphasize that the pathogenesis of LOAD is multifactorial, with bioenergetics being one part of risk determination and note that the skin fibroblasts studied are not the primary cell type that is affected in LOAD.

“However, because bioenergetics changes are body-wide, observations made in fibroblasts may also be relevant to brain cells,” said Sonntag. “In fact, metabolic changes like diminished glucose uptake and insulin/IGF-1 resistance may underlie the association between various disorders of aging, such as type 2 diabetes and AD.”

Sonntag and Cohen are already in the midst of follow-up work aiming to study these bioenergetics features in brain nerve cells and astrocytes generated from LOAD patient-derived induced pluripotent stem cells, as an aging and disease model in the dish. It is the group’s hope that findings from these studies will reveal further insight into the role of bioenergetics in LOAD pathogenesis and novel targets for intervention—both prevention and treatment.

Journal article:
https://www.nature.com/articles/s41598-017-14420-x

Source:
https://www.mcleanhospital.org/news/alzheimers-disease-disorder-energy-metabolism-new-study-shines-new-light

#alzheimersdisease #betaamyloid #glycolysis #bioenergetics #neuroscience #medicine #research
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‪Unidos le decimos al régimen represivo #OrtegaMurillo #QueSeVayan RT: En un hecho sin precedentes en la historia reciente de #Nicaragua, miles de nicas le dijeron: ¡Ya no más! al Gob represivo de #Ortega. ow.ly/GidX30jDVCQ #SOSNicaragua #Nicaragua #ResistenciaCiudadana

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Thank you @Pontifex for speaking out against the unspeakable violence waged by the #OrtegaMurillo brutal regime against unarmed civilians in #Nicaragua RT Pope calls for end to violence in Nicaragua after 25 killed
Journalist shot dead while broadcasting live in Nicaragua as death toll hits 25 https://www.theguardian.com/world/2018/apr/22/journalist-among-25-killed-as-unrest-escalates-in-nicaragua?CMP=share_btn_tw

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#StopCuttingDownOurTrees RT #Deforestation is the permanent destruction of forests to make the land available for other uses. An estimated 18 million acres roughly the size of Panama, are lost each year, according to the UNs' Food and Agriculture Organization @FAO https://shar.es/1LQVNV via @LiveScience #SaveOurTrees
Live Science
Live Science
livescience.com

I agree with Christiane Amanpour’s argument that we cannot negotiate with #Assad a #WarCriminal who gasses his own people, and has Russian military support because he has a deal over oil revenue with #Putin vs Rachel Shabi’s ridiculous and naive argument that we can negotiate with Assad, #Marr
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