Darkthorn’s Blog

PNS

• • nerve fibres regenerate depending on their location

• • Schwann cells guide the regeneration of cut axons

CNS

• • repair and functional regeneration is limited

  • myelin associated inhibitory factors

  • astrocyte scar formation and age related decline in repair mechanisms

Spinal Cord Damage

• • mainly due to cell death, inflammation, expanding cysts and glial scarring, also degenerating tracts, demylination and atrophied muscles

  • some spontaneous repair – gliogenesis, sprouting axons, cortical sensory motor arrangement, some rubriospinal compensation

  • prevents expansion of critical damage, create bridges, promote axon regeneration, compensate for demylination, replace dead cells

  • parapligia or quadriplegia

Parkinson’s Disease

• • disordered control over movements

  • loss of dopaminergic neurons in pars compacta of substancia nigra

  • actions – increase L-dopa, inhibit degradation by MAO-B, stimulate release of dopamine, block action of Ach in striatum

  • mechanisms – overactive glutamate producing cells affected by free radicals

Stem Cells

• • stem/progenitor cells are self renewing and can be used for gene therapy

  • can differentiate into neurons or glia

  • neurosphere – a clone of cells from a single neural stem cells (multipotent)

  • can be treated with factors for promoting neural differentiation

Other Pathways

• • growth and migration factors

  • functional integration (axon growth and guidance molecules)

  • increase in the number of neurons

Carbohydrate Catabolism

1. During the preparatory stage of glycolysis, the molecule of glucose is phosphorylated, and converted into two molecules of glyceraldehyde-3-phosphate. This requires the use of two ATP molecules.

In the payoff phase, the glyceraldehyde-3-phosphate is converted to pyruvate. This releases four ATP molecules, and produces two NADH molecules.

1. In the preparatory phase the phosphate groups are obtained from 2 ATP and attached in place of the OH groups, producing glyceraldehyde-3-phosphate, and leaving 2 ADP molecules behind.

In the pay-off phase, a molecule of Pi replaces the H group, releasing electrons to form NADH and 1,3-biphosphoglycerate. The phosphate group is then removed by ADP to form ATP and 3-phosphoglycerate.

1. Substrate-level phosphorylation is the transfer of a high energy phosphate group from 1,3-biphosphoylate/phosphoenolpyruvate to ADP to produce ATP and a molecule of 3-phosphoglycerate/pyruvate.

1. Although the conversion of glucose to glucose-6-phosphate is endergonic (requires energy, in the form of 2 ATP molecules), the overall process of glycolysis still proceeds. This is because the overall reaction is exogonic, and the later stages have excess energy to help the first reactions proceed.

1. For humans, pyruvate has two possible metabolic fates. In anaerobic conditions, such as during a sprint, pyruvate undergoes fermentation (in active skeletal muscle, the retina or red blood cells) to produce lactate and ATP. This method of producing energy is very inefficient compared to the energy produced under aerobic conditions. In aerobic conditions, during everyday cellular respiration, pyruvate is further oxidised to form the eventual products of carbon dioxide and water.

Lipid Catabolism

1. There are six steps in the digestion and transport of dietary lipids to adipose tissue.
   1. In the small intestine fat is emulsified by bile salts secreted from the gall bladder to produce mixed micelles.
   2. Triacylglycerols within the mixed micelles are degraded by intestinal lipases into monoacylglycerols, diacylglycerols, free fatty acids and glycerol.
   3. These products then diffuse into the epithelium cells lining the intestinal surface where they are reconverted into triacylglycerols.
   4. The insoluable triacylglycerols are packaged with phospholipids, proteins and cholesterol to form chylomicrons. Chylomicrons then move from the epithelial cells into the lymphatic system, where they can enter the bloodstream.
   5. The chylomicrons move through the bloodstream until the reach adipose tissue. They are then degraded into their original parts (releasing free fatty acids and glycerol) within the capillaries of the adipose tissue.
   6. The freed fatty acids are taken up by the cells, where they are reesterified for storage as triacylglycerols.

The mobilisation of stored lipids maintains the body’s energy levels during starvation (both long term and between meals). Low glucose levels in the blood cause the release of hormones which activate the enzyme triacylglycerol lipase. This stimulates the breakdown of stored fatty acids into fatty acids and glycerol – the fatty acids are transported by serum albumin to the muscles and the glycerol is recycled back to the liver. This is basically the reverse of the fats original breakdown.

1. The CoA pool in the intermembrane space provides the CoA required to generate the first stage Fatty Acyl-CoA from a fatty acid. CoA is then replaced by carnitine so that the fatty acid can pass across the membrane. The second pool of CoA releases the carnitine (to pass back into the intermembrane space) and regenerates Fatty Acyl-CoA. The carnitine prevents the two pools from interacting because it is the only thing allowed across the membrane.
2. The four reactions of B-oxidation are: oxidation, hydration, another oxidation and thiolytic cleavage.
3. Reduced electron carriers are generated by reaction 1 (FAD à FADH) and reaction 3 (NAD+ à NADH).

learning – the acquisition of new information or knowledge

memory – the retention and accessing of learned information

classes of memory

• • short term – phonological loop

    • • • • visuospatial sketchpad

• • long term – declarative (facts, places, events)

    • • • • perceptual

          • nondeclaritive (subconscious)

• • • relies on physical changes in neuronal circuits

    • reinforcement of particular synaptic pathways

    • changes in membrane receptors

    • hippocampal/medial temporal cortex involved in formation of long-term memories and the storage of recently formed long term memories

    • this may require the formation of new neurons

    • long term declarative memories are stored as synaptic circuits in the cerebral cortex

    • not all long term memories are declarative, as they can form without conscious acknowledgement

neuronal activity

• inferior temporal cortex important for facial recognition

• cells respond differently between different stimuli on training

Amnesias

• retrograde – previous memories removed after trauma

• anterograde – no memory after trauma

perceptual learning – practice in sensory tasks allows the person to perform finer discriminations, stored in primary sensory areas

visuomotor learning – compensating for visual disturbances (within cerebellum)

fear conditioning – amygdala coordinates behavioral, emotional and autonomic responses to sensory stimuli, learning association relies on this circuit

As most of you will have noticed, I’m no longer updating with any creative stuff. Currently, there is a lot of university things going on, such as those all-important, stupid exams. I hope you are all enjoying the excerpts from my learnings, and are willing to hang around until I put up a few more creative things. I’m still working on them, just very slowly.

I updated the ‘Accreditations’, ‘FAQ’ and ‘Thanks’ pages today, so if you wondered why they weren’t right, well, they are now.

Bear with me

~ Darkthorn

Regeneration of the Nervous System

- Peripheral nervous system axons can be repaired and regenerated to restore function (only partially, and connections are not always as efficient) due to Schwann cell mylination.

- Central nervous system cannot be replaced (oligodendrocytes).

- Environmental factors effect whether the axon’s growth cone is able to repair the damage by growing out.

- Lower amphibians can regenerate both PNS and CNS

o Neuroprogenital cells are more redily recruited to help in urodeles

o Developmental signalling molecules are still expressed in adult urodeles

- Higher vertebrates (chicks) can perform regeneration during development, possibly because neurons are not yet mylinated.

Mammalian Models

- Primates – very similar to humans, and have large brains. Live for long periods of time, need lots of living space, and are expensive to keep.

- Large mammals – less similar to humans, and still live for long periods of time.

- Small mammals – still similar to humans, but brain size is a lot smaller. Life-span is still a little long, but relatively cheap to maintain.

- Rodents – can have prominent differences from humans, but are cheap to keep with very short life-spans and breeding schedules.

Specialised models are used to study different aspects of neuroscience

- Birds – auditory

- Amphibians

- Flies/worms/yeast

- Sea creatures

Specific Studies

- Squid

o giant axon, size gives it speed (not mylinated)

o stellate ganglion has many axons to innervate mantle and musculature to provide a coordinated response

o used to study: movement of ions through channels, transport of proteins along axon, how cellular pH is maintained

- Frog

o Specifically the African Clawed Frog

o Use oocytes for detecting recombinently expresses proteins (via electrophysical recordings

- Torpedo Rays

o Use a localised electrical charge to stun prey

o Originally used to determine structure of nicotinic acetylcoline receptors (linear array)

- Aplysia

o Sea snail/slug/hare

o Most neurons are large and readily identifiable, as well as being unique in function (used for studying reflexes)

o Can be used to understand simple forms of learning and experience (non-associative learning and habituation/sensitisation of gill-withdrawal reflex)

- C. Elegans

o Nematode (worm), self-fertilising hermaphrodite with a very short lifespan

o Limited number of cells (302 neurons, 959 somatic cells)

o Morphology, position and connectivity of neurons is definite (118 classes of neuron)

o The genome has been sequenced, so we know how to alter gene expression

o Their bodies are clear, so can watch protein expression while still alive

o Mutations of particular genes can cause alterations in behaviour/movement: check GABAergic and dyrein malfunction

- Fruit-fly

o Very small, prolific and has a short lifespan

o Studies of genetics and development

o Different neurotransmitters are involved in different types of learning (dopamine in aversive memory formation)

o Neuropharmological models are studied to see the effects of drugs in improving genetic neuropathologies and drug interferences

FRANKSTON: SECURITY ON THE RISE
frankston security/herbert/june 28/300 words
By Rosemarie Herbert

Improvements to security at Frankston Train Station have included the establishment of a Safer City Centre (2002), the implementation of a Hoon Hotline (2005) and an Ambassador Program (2006).

Currently, gentle classical music is played throughout Frankston Train Station and Young Street in an effort to reduce vandalism and graffiti in the area.

The station master at Frankston claimed that undesirables have an aversion to the music, but it seemed to be frustrating everyone else as well.

“We have found that those the music was set to target have mostly been driven away. Everyone else has a bit of a dislike of it too though,” he said.

Frankston has a notorious history with young people fulfilling the stereotype role of erratic drivers, drag racing, wilful damage, suspect loiterers and thieves.

One incident in March 2008 saw two teenagers performing vandalism and graffiti acts on trains causing more than $5000 worth of damage.

Drug use, antisocial behaviour and vandalism are all set to be targeted by the Frankston 2025 Community Planner.

A suggestion is for local businesses to create graffiti walls for local artists to display their work in designated areas.

The use of security guards has dealt with problems such as young people gathering in reserves on Friday and Saturday nights and causing disturbances to neighbours.

Some reserves have been deemed “no entry” areas at night to further reduce the problem.

A Safer City Centre, established in 2002 in conjunction with Victoria Police and Wilson Group Services, is located directly opposite the Frankston Train Station.

Regular foot police patrols in the area keep theft to a minimum, as well as protecting walkers and businesses in the area from unwanted advances.

The Centre, which is accessible to all visitors and residents of Frankston, is open Monday to Friday, 9:30am to 5:30pm.

ENDS

The girl woke up. She looked around, for some reason unable to move her neck. She let her eyes roam around the room, wondering at the clean white expanse of the space. Suddenly, all the events leading up to this moment rushed back. Her thoughts went first to poor Sal. They wouldn’t know what had happened to her! Not that her useless father would care, but Sal would be worried. She tried to remember if she had had her wallet.

There was movement next to her, and a face swam into view. The girl couldn’t focus properly. The face wasn’t a familiar one. She realised why it was disembodied, the figure was wearing a white coat that blended exactly with the background. The girl thought about the first thing she could say. On TV, it was “where am I?” or, depending on the extent of the character’s brain damage “who am I?” She knew both of these answers, but hold on; someone was speaking to her first.

“You’ve been in an accident and you’re in the children’s hospital. You were badly hurt, and in a coma. Do you know who you are?”

The girl attempted to swallow and frantically tried to recall if she had been carrying any ID. She decided no, there wasn’t any. Her mother’s name rolled off her tongue, a fresh reminder of why she deserved to be here.

“I am Anna.”

Julia dreamt and Blackmain and Ishton watched. She/they ran, her/their legs barely carrying her/them into forest. She/they tripped and fell, breathing heavily. Escape. She/they couldn’t escape. She/they crawled towards the base of a tree, noticing that her/their skin was weeping blood from the scratches on her/their arms. As she/they watched, more cuts opened on her/their legs. She/they was going to bleed to death. She/they couldn’t even remember what she was running from. Maybe it would be better to give in, give up, accept whatever was chasing her/them, claim death as her/their own. The last thing she/they had power over.

Included within Julia’s thoughts, Blackmain shuddered. Her/their own body was betraying her/them, her/their mind was trapped. How could she/they be freed? He watched in horror as a dream version of Cimon stepped into the clearing and began to taunt her/them, even as Julia’s/their flesh caught on fire. The rape that followed was callous, but well-thought out. Blackmain almost cried out in horror, but as Julia wasn’t, he couldn’t either. The dream Julia lay still and Blackmain felt her/their heart stop for a moment. Then she/they began running again.

Blackmain tried to pull away, but found that he could only whimper within their shared mind.

~ Who is there? ~ The voice had a distinct Julia twinge to it, full of the pain they were trying to rescue her from.

~ It is us. ~

~ Go away. I like it here. I can control what happens. ~

~ You are trapped. You just don’t remember what has happened, that you are repeating yourself. You can’t control anything. ~

~ I can so. ~

Julia wrenched her mind away from theirs. How dare they invade? This was her private place. She would show them. She wasn’t giving up. The pain in the cuts reminded her finally of what it really felt like to be alive. They were right. No, they weren’t. If this was a dream, she wouldn’t have any control. Her mind was so occupied that it didn’t notice when Cimon began raping her again. She clung to her thoughts, not letting go, even as her heart stopped and her body stopped being responsive.

She tried desperately to hold the cuts closed with her hands, but more kept on coming as fast as she could tie them off. Ishton distanced himself from her mind and helped her. Now that she was trying for herself, he could help. She glared at him, but accepted the assistance. Her head bent down dealing with the ones on her legs, she didn’t notice Cimon approaching. When he grabbed her hair, Julia, already weakened by the blood loss collapsed. Cimon raped her again and again, this time she could feel it. She and Blackmain, who was still trapped with her mind, screamed.

Suddenly Blackmain was free. His spectral body formed, and he pulled Cimon away from her, just as he had done in real life. He knelt over Julia, helping Ishton to bind her wounds. The dream stopped. Everything stopped. Julia took a deep breath, and rolled away.

~ Leave me alone. I wanted to die here. It’s my choice. ~

~ You wouldn’t, couldn’t have died. We wouldn’t let you. We need you to be whole and healthy. Please don’t hide from us. We found you to save you. ~

~ I wanted to die. ~

Julia hid her face, and cried. The tears fell down, and sizzled as they hit her still burning flesh. It healed over, and it was as if a flood tide had been released. Cuts and bruises healed over, leaving her whole again.

~ Come with us, Julia. Be with us. We will not harm you. We have never wanted to harm you. ~

~ Tell me the truth. ~

~ We will. Just not here. ~

And indeed, the dream forest was fading away, leaving a clinging mist. Blackmain and Ishton hauled Julia to her feet, she was still weak and relatively helpless. They lifted her out, to return to the real world, where everyone was awaiting the results.

RSC MUSIC
rsc music program/herbert/july 24/310 words
By Rosemarie Herbert

2008 has been a boom year for music at Rosebud Secondary College.

The opening of the Southern Peninsula Performing Arts Centre and associated music classroom upgrades last year have provided much needed space for students.

Five individual practice rooms as well as two larger classrooms provide space for both instrumental (brass, strings, woodwind) and classroom (drums, keyboard, guitar) music.

Mr. Matthew Flynn, an instrumental teacher at several other local schools as well as the College, said that the number of students he is required to teach is getting excessive.

“I had to write over 400 reports last semester, and yet more students have joined the music program since then,” he said.

On days their other music teacher is away, students are still looking to escape regular class, claiming the need for ‘practice time’.

A senior music student mentioned that some of the students participating in the compulsory after-school band rehearsals were very disruptive.

“They can’t seem to concentrate for very long, they are forever giggling during practice,” she said.

Students are encouraged to enjoy various music events throughout the year, including SoundWaves (a vibrant interschool event), a camp and several concerts.

A recent school camp to Wilson’s Promontory involved over thirty members of the school’s concert band.

Activities on the camp included team building exercises, watching inspirational movies, several rehearsals a day and giving concerts at local primary schools.

Teachers said that the students were well-behaved and that another camp would definitely be in the works for 2009.

“With all the up-and-coming year 9 students, plus the new intake of students in year 7 next year, we will be considering a camp in the near future.” said Sam Clough, the band’s leader.

Expressions of interest for assisting at the proposed 2009 camp, or with the college music program in general, can be directed to the Music Department on 5986 8595.

ENDS