eSagan 🇮🇳 @crackurbones@qoto.org
Joined Nov 2019
🔸 One source of brain tumors is metastasis -- which are spreads from other tumors, so for instance, lung tumors.
🔸 The brain tumors are a problem because they exist within the cranium, and the cranium is a fixed, bony container. It can't expand. And as a tumor expands, the cranium is not going to expand. It's going to increase the pressure and we're going to have a problem.
🔸 Neurons don't make tumors because they don't divide at all, and they don't get into this uncontrolled division. So what makes tumors? Well, it's other cell types within the brain. And the primary one that does this are #GlialCells.
🔸 Glial cells don't have the limits on division that neurons do. So, glial cells can divide and make these tumors. And so, #gliomas, tumors of glial cells, are the most common type of brain tumor.
🔸 Another type of brain tumor is the type that comes from a division of meningeal cells, and these are called #meningiomas.
🔸 And finally, the other major type of brain tumor is are tumors that come from glandular cells.
🔸 These glandular cells are not neurons. They're gland cells, and they can divide without control. The other gland that we have in our head is called the pituitary, and these pituitary cells can also divide and that's called 'pituitary adenomas'. These #PituitaryAdenoma's are fairly common. They account for about 10 to 25% of inter-cranial tumors.
🖼️ Image source: https://images.app.goo.gl/hfXZKhrd7ahacDsx9
#WhatsApp is so popular in #Africa, even knock-off versions are used more often than Facebook https://qz.com/africa/1804859/
GB WhatsApp, the most widely used WhatsApp mod across major African markets, allows users operate multiple accounts, restore deleted messages and send and receive larger media files (up to 50 megabytes compared to 16 megabytes on WhatsApp). #GBWhatsApp also offers users more control of privacy settings, including hiding features that notify others when users are online, recording a voice-note or typing a message.
Dettol Products Work Against Novel Coronavirus? Here’s The Truth https://in.news.yahoo.com/dettol-products-against-novel-coronavirus-054134907.html?soc_src=hl-viewer&soc_trk=tw
While responding to a user on Twitter, Reckitt Benckiser Group (RB), the manufacturers of Dettol products, clarified that the ‘product is effective against other coronaviruses (MERS-CoV and SARSCoV)‘ but they don’t have access to a sample of the novel coronavirus to make any such claim.
Indira Gandhi, Amrit Kaur named by TIME among '100 Women of the Year' https://in.news.yahoo.com/indira-gandhi-amrit-kaur-named-150115211.html?soc_src=social-sh&soc_trk=tw
After India got independence in 1947, Kaur became the first woman to join the Cabinet, serving as Health Minister for 10 years. In that position, she founded the Indian Council for Child Welfare; helped establish the country’s top hospital and medical college; and campaigned to prevent malaria, likely saving hundreds of thousands of lives, the TIME profile said.
🔸 The #meninges form a very effective barrier against toxins, viruses, against all sorts of damage, so that the peripheral nervous system tends to be far more vulnerable than the central nervous system.
🔸 In addition, the two regions have very different capacities for repair.
🔸 If you cut an axon in the peripheral nervous system, it can repair itself -- It will reconnect. If there's a traumatic injury to the central nervous system, the same does not happen. So, the ability to repair is far, far greater in the periphery than in the central nervous system.
🔸 A large molecule called botulinum toxin, which comes from spoiled food, can get in and it primarily will affect the peripheral; it will only affect the peripheral neurons. It will not get past the meninges.
🔸 #PolioVirus actually gets in right at the synapse between the motor neuron and the voluntary muscle, and it goes back. It travels back and it does a clever thing -- It gets through the meninges, but it gets through the meninges by getting in through an axon of a motor neuron. And what does it do then? For thanks, it actually kills this motor neuron. So now, that motor neuron is going to die.
🔸 Let's look at another virus: herpes zoster.
Herpes zoster is a virus that produces, what's commonly called as, #shingles. And in herpes zoster, the virus gets into the dendrites of sensory neurons, and it gets transported back inside the axon in these sensory neurons, and then it goes and lives in synaptic terminals. And if all is great, it lives in there and then it never talks again.
🔸 But, under some circumstances, the virus can decide to reproduce and blossom, and it will make copies of itself so that it actually sends it back out. And what you get is a virus all throughout the sensory territory and what you get is a rash.
#Isro postpones launch of geo-imaging satellite Gisat-1 due to technical reasons
https://www.indiatoday.in/science/story/isro-postpones-launch-satellite-gisat1-technical-gslv-f10-1652399-2020-03-04
Human brains have ‘time cells’ that let us recall when events happened | New Scientist
https://www.newscientist.com/article/2236167-human-brains-have-time-cells-that-let-us-recall-when-events-happened/
Is time broken? Physicists filmed a quantum measurement but the 'moment' was blurry
https://thenextweb.com/insights/2020/03/03/is-time-broken-physicists-filmed-a-quantum-measurement-but-the-moment-was-blurry/
🔸 There's a barrier, a fence that is the demarcation between central and peripheral nervous-systems. And that fence is made up of three membranes, and those three membranes are the 'meninges'.
🔸 There are three meningeal layers, and the three layers go from very weak, very tender, the pia, to very tough, the dura and, in between, there's a spidery thing called the arachnoid.
🔸 The only neurons that leave the central nervous system are the neurons that serve a motor function.
They actually go out the meninges and they go into the periphery. In the periphery, there's the peripheral nervous system, and there's also the rest of the body.
🖼️ Image Source: https://www.thoughtco.com/brain-anatomy-meninges-4018883
🔴 Demyelinating Diseases
🔸 The #glialcells that make the myelin are of different types that make it (myelin) in the central nervous system and in the peripheral nervous system. And because of that, people who get a demyelinating disease, get it either in the central nervous system or in the peripheral nervous system -- but not in both.
🔸 So the problem is either in the #oligodendrocytes (and the interaction between the oligodendrocytes and the axon) -- in which case you get a central demyelinating disease, and the most common by far is multiple #sclerosis -- or there's a problem in the #SchwannCell and its connection to the axon, and in that case you can get a variety.
🔸 There are a diverse group of hereditary neuropathies called Charcot-Marie Tooth, which are #DemyelinatingDiseases. They're inherited and they typically progress and become worse with time.
🔸 There's also an acute demyelinating disease called Guillain–Barré, which typically has a very quick onset, it's inflammatory, and luckily it goes away after a while.
#IITMadras Develops AI Powered Drone Which Can Hack Into Rogue Drones And Forcibly Land Them https://swarajyamag.com/insta/iit-madras-develops-ai-powered-drone-which-can-hack-into-rogue-drones-and-forcibly-land-them
#India #AI
Consciousness Isn’t Self-Centered
https://www.3quarksdaily.com/3quarksdaily/2020/03/consciousness-isnt-self-centered.html
🧠 Myelin is a fatty wrap that goes around some axons.
🔸 An unmylinated or naked axon can only transfer information at a slow rate. So the rate that it's transfers information is 0.2 to 1 meters per second.
🔸 Now, once we put on #myelin, information transfers much much faster. It can go between 2 and 120 meters per second. If it goes at 120 meters per second, the whole game is over. So very short time, imperceptible to us.
🔸 That information occurs in a 0 or a 1. There's either a point of information or not. **And so it's very much like a computer code**, where what we're seeing is a series of and what's important, the 0s are less important but the temporal pattern of these ones is very important.
🔸 And these 'ones' are actually an action potential, also called a spike. And we talk about firing spikes, neurons fire spikes. So, the timing of these spikes is what carries information.
🔸 The information spikes actually jump. That's what makes it so fast. They don't have to actually be carried through the places; with the #Myelin, they can actually jump.
🔸 And now, if we have a #DemyelinatingDisease, what we're going to end up with is some information that's spread out, because it's slower. And every once in a while, it's going to miss bits.
🔸 The neuron, that we're talking, to is getting a very incoherent message. This is very different from the original message and that is the problem with demyelination. Because axons are demyelinated, the information transfer is very degraded. It's a garbled message and that's a problem.
Image source: Screen-grab from https://www.coursera.org/learn/neurobiology/lecture/B13Z1/myelin.
**Glial Cells**
The human brain contains 86B neurons and 85B Glia.
**Different types of Glia:**
🔸 Astrocytes: Astrocytes are really important type of Glia. They're essentially responsible for keeping the environment clean, they're the sanitation worker of the brain. So they are picking up all the refuse that the neurons have let loose including excess ions, excess #neurotransmitters and their metabolites.
They also are very important during development. They allow neurons to get to where they have to go during development. #Neurons are born in one place and they have to go some place else, and what highway did they take? They hitch on a progenitor cell that is going to become an #Astrocyte.
And, in addition when synapses are formed, the synapses are not maintained without some effort, and part of that is that the synapses are enveloped in the processes of #Astrocytes. So, there's a lot of structural and metabolic support that the Astrocytes are providing for neurons.
🔸 Oligodendrocytes and Schwann Cells: The #oligodendrocytes make myelin in the CNS and the #SchwannCells make it in the Peripheral Nervous System. So all these demyelinating diseases will affect either central myelin or peripheral #myelin. They will not affect both -- central or peripheral.
Because they are made by two different types. The Oligodendrocytes in the central nervous system and a Schwann cells in the peripheral nervous system.
🔸 Microglia: #Microglia are the one exception to the rule that
nervous system, that the cells of the nervous system come from Ectoderm. These are actually essentially immune cells coming from the blood lineage. These are immune cells that have invaded into the central nervous system and their job is to be quiet. And if we're healthy and everything goes well, they are quiet. But when there is a problem these microglia react, they try to rectify things, they try and bring some attention to areas of damage and what is emerging is that sometimes they go overboard and they start to participate in making the problem as well as solving the problem.
Ancient #Mongolia'n empires sustained themselves with millet | Cosmos
https://cosmosmagazine.com/archaeology/ancient-mongolian-empires-sustained-themselves-with-millet
eSagan 🇮🇳
boosted
@crackurbones I like Sam O'Nella's theory about neanderthals:
eSagan 🇮🇳
boosted
Researchers in #Antarctica found a thriving ecosystem of #MicrobialLife in an underground lake
https://www.dailymail.co.uk/sciencetech/article-8075811/Researchers-Antarctica-thriving-ecosystem-microbial-life-underground-lake.html
Doctors use gene editing tool #Crispr inside body for first time
https://www.theguardian.com/science/2020/mar/04/doctors-use-gene-editing-tool-crispr-inside-body-for-first-time?utm_source=dlvr.it&utm_medium=twitter
🐤 https://twitter.com/guardianscience/status/1235248526927343616
Joined Nov 2019
