Tag: dyskinesias

Isradipine: Posthoc analysis

~ Simon ~ 4 Comments

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Last year the results of the large STEADY-PD study were published. The investigators behind the Phase III clinical trial reported that the experimental treatment being tested had no effect on the progression of Parkinson’s in recently diagnosed individuals.

The treatment being evaluated was a calcium channel blocker called isradipine – it is used for treating high blood pressure.

Since publishing the results, some of the researchers behind the study have been conducting post hoc analysis of the data… and they have found something interesting: An effect.

In today’s post, we will look at why isradipine was evaluated in Parkinson’s, what the results of the STEADY-PD study were, and what the newly discovered effect could mean.

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Source: Medium

In the scientific world, post hoc analysis (from the Latin post hoc, meaning “after this”) consists of statistical analyses that are specified after the data has been seen. This type of analysis should only be considered for “hypothesis forming” exercises, and not be viewed as cherry-picking of the data in order to find an effect. 

And one must be careful with interpretation of data (eg. most people who are involved in car crashes have been reported as wearing clothes at the time of the incident, thus we should get rid of clothes to assess if this will reduce the incidence of automobile accidents).

Post hoc analyses of completed clinical trial data, however, can be very useful process of identifying interesting trends that could be explored in future studies.

A good example of this has recently been conducted on the STEADY-PD clinical trial study.

What was the STEADY-PD clinical trial about?

Continue reading “Isradipine: Posthoc analysis” →

Getting a GRP on dyskinesias

~ Simon ~ 8 Comments

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Dyskinesias are involuntary muscle movements associated with long-term use of levodopa therapy (use of levodopa is not a certainty for developing dyskinesias, but there is an association).

A better understanding of the underlying biology of dyskinesias is required in order to alleviate this condition for those affected by it.

This week researchers reported that a single protein – called RasGRP1 – plays a central role in the development of dykinesias, raising hope that agents targeting this protein could identified and provide better quality of life of sufferers.

In today’s post, we will discuss what dyskinesias are and review the new research.

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Few people outside of the biomedical sciences may have heard of the Scripps Research Institute, but it is the largest private, not-for-profit medical research facility in the United States and among the largest in the world. It is headquartered in La Jolla, California but it has a sister facility in Jupiter, Florida.

Nice spot to do research. Source: Scripps

Collectively, “The Scripps” has 250 laboratories, which employs over 2,400 scientists, technicians, graduate students, and administrative staff.

It was founded in 1924 by journalist/philanthropist Ellen Browning Scripps.

Ellen Browning Scripps. Source: Lajollalight

The Scripps covers a wide variety of area in biomedical research, but this week a group of researcher led by scientists at the Florida Scripps institute published an interesting report on Parkinson’s:

Title: RasGRP1 is a causal factor in the development of l-DOPA–induced dyskinesia in Parkinson’s disease
Authors: Eshraghi M, Ramírez-Jarquín1 UM, Shahani1 N, Nuzzo T, De Rosa A, Swarnkar S, Galli N, Rivera O, Tsaprailis G, Scharager-Tapia C, Crynen G, Li Q, Thiolat ML, Bezard E, Usiello A, Subramaniam S
Journal: Science Advances, May 2020, 6, 18, eaaz7001
PMID: 32426479                 (This report is OPEN ACCESS if you would like to read it)

In this study, the researchers were interested in proteins that could be playing a major role in the development of dyskinesias.

What are dyskinesias?

Continue reading “Getting a GRP on dyskinesias” →

Time to resTOR in New Zealand

~ Simon ~ 15 Comments

 

As the amazing Australian Parkinson’s Mission project prepares to kick off, across the creek in my home land of New Zealand, another very interesting clinical trial programme for Parkinson’s is also getting started. The study is being conductetd by a US biotech firm called resTORbio Inc.

The drug being tested in the study is called RTB101.

It is an orally-administered TORC1 inhibitor, and it represents a new class of drug in the battle against Parkinson’s. 

In today’s post, we will look at what TORC1 is, how the drug works, the preclinical research supporting the trial, and what this new clinical trial will involve.

 

Rapa Nui. Source: Chile.Travel

Today’s post kicks off on an amazing south Pacific island… which is not New Zealand.

In 1965, a rather remarkable story began in one of the most remote inhabited places on Earth – the mysterious island of Rapa Nui (or “Easter Island”).

And when we say ‘remote’, we really do mean remote. Did you know, the nearest inhabited island to Rapa Nui is Pitcairn Island, which is 2,075 kilometres (1,289 mi) away. And Santiago (the capital of Chile) is 2,500 miles away – that’s a four-hour+ flight!!!

Rapa Nui is the very definition of remote. It is as remote as remote gets!

Does Amazon deliver to the town of Hanga Roa? Source: Atlasandboots

Anyways, in 1965 a group of researchers arrived at Rapa Nui with the goal of studying the local inhabitants. They wanted to investigate their heredity, environment, and the common diseases that affected them, before the Chilean government built a new airport which would open the island up to the outside world.

It was during this investigation, that one of the researchers – a University of Montreal microbiologist named Georges Nógrády – noticed something rather odd.

What?

At the time of the study, wild horses on Rapa Nui outnumbered humans (and stone statues).

Wild horses roaming the east coast of Rapa Nui. Source: Farflungtravels

But what was odd about that?

Georges discovered that locals had a very low frequency of tetanus – a bacterial infection of the feet often found in places with horses. He found this low incidence of tetanus particularly strange given that the locals spent most of their time wandering around the island barefoot. So Georges decided to divide the island into 67 regions and he took a soil sample from each for analysis.

In all of the vials collected, Nógrády found tetanus spores in just one vial.

Something in the soil on Rapa Nui was extremely anti-fungal.

In 1969, Georges’ collection of soil samples was given to researchers from the pharmaceutical company Wyeth and they went looking for the source of the anti-fungal activity. After several years of hard work, the scientists found a soil bacteria called Streptomyces hygroscopicus which secreted a compound that was named Rapamycin – after the name of the island – and they published this report in 1975:

Title: Rapamycin (AY-22, 989), a new antibiotic
Authors: Vézina C, Kudelski A, Sehgal SN.
Journal: J Antibiot (Tokyo). 1975 Oct;28(10):721-6.
PMID: 1102508              (This report is OPEN ACCESS if you would like to read it)

It is no understatement to say that this was a major moment in biomedical history. So much so that there is actually a plaque on the island commemorating the discovery of rapamycin:

Source: DiscoveryMag

Why was the discovery of ‘anti-fungal’ rapamycin so important?!?

Continue reading “Time to resTOR in New Zealand” →

Xenon: A bright light for dyskinesias?

~ Simon ~ 13 Comments

A recent study published by French, British and Swiss researchers has grabbed the attention of some readers.

The report suggests that the inert/noble gas, Xenon, has powerful anti-dyskinetic properties in both mouse and primate models of Parkinson’s with L-DOPA-induced dyskinesias.

Dyskinesias are involuntary movements that can develop over time with prolonged used of L-DOPA treatments.

In today’s post, we will discuss what Xenon is, how it may be reducing dyskinesias, and we will consider some of the issues associated with using Xenon.

Dyskinesia. Source: JAMA Neurology

There is a normal course of events following a diagnosis of Parkinson’s.

Yes, I am grossly over-generalising, and no, I’m not talking from personal experience, but just go with me on this for the sake of discussion.

First comes the shock of the actual diagnosis. For many it is devastating news – an event that changes the course of their future. For others, however, the words ‘you have Parkinson’s‘ can provide a strange sense of relief that their current situation has a name and gives them something to focus on.

This initial phase is usually followed by the roller coaster of various emotions (including disbelief, sadness, anger, denial). It depends on each individual.

The emotional rollercoaster. Source: Asklatisha

And then comes the period during which many will try to familiarise themselves with their new situation. They will read books, search online for information, join Facebook groups (Click here for a good one), etc.

That search for information often leads to awareness of some of the realities of the condition.

And one potential reality that causes concern for many people (especially for people with early onset Parkinson’s) is dyskinesias.

What are dyskinesias?

Continue reading “Xenon: A bright light for dyskinesias?” →

The aggregating antics of (some) anaesthetics

~ Simon ~ 7 Comments

This is one of those posts that I am reluctant to write because there is the very real possibility of it being taken out of context and causing someone to panic. But several readers have asked me to address a new piece of research that was published this week which has them concerned.

Anaesthetics are very useful agents in medicine, but they have long been known to have biological effects beyond simply numbing/sedating individuals. Some of those effects are beneficial, while others….mmm, not so beneficial. And the new research published this week leans towards the latter: Certain anaesthetics apparently induce mutant protein aggregation in neurons and cause stress responses in those brain cells.

In today’s post, we will discuss what anaesthetics are, how (we think) they work, and what the results of this new research actually mean.

William Morton’s first public demonstration. Source: Pinterest

On Friday 16th October 1846, history was made.

On that date, an American dentist named William T. G. Morton (1819-1868) made the first public demonstration of the use of inhaled ether as a surgical anaesthetic.

William Morton. Source: Wikipedia

At this demonstration Dr. John Collins Warren painlessly removed a tumor from the neck of a Mr. Edward Gilbert Abbott. After finishing the operation and Abbott had regained consciousness, Warren asked Abbott how he felt.

John Collins Warren. Source: General-anaesthesia

Abbott replied, “Feels as if my neck’s been scratched.”

Warren then turned to the medical audience and said:

“Gentlemen, this is no Humbug”

This was an obvious shot at an unsuccessful demonstration of nitrous oxide as a anaesthesia the year before (by Horace Wells in the same theatre), which ended with the audience shouting “Humbug!” after they heard the patient groaning with pain during the procedure.

The important thing to appreciate here is the magnitude of Morton’s achievement within in the history of medicine.

Before 16th October 1846, surgical procedures were not very pleasant affairs.

After 16th October 1846,… well, to be honest, they are still not very pleasant affairs, but at least the patient can skip most of the painful parts of an operation.

Interesting. But what does this have to do with Parkinson’s?

Continue reading “The aggregating antics of (some) anaesthetics” →

Is there NOP hope for Parkinson’s?

~ Simon ~ 8 Comments

Please do not misread the title of this post!

Compounds targeting the Nociceptin receptor (or NOP) could provide the Parkinson’s community with novel treatment options in the not-too-distant future.

In pre-clinical models of Parkinson’s, compounds designed to block NOP have demonstrated neuroprotective properties, while drugs that stimulate NOP appear to be beneficial in reducing L-dopa induced dyskinesias. 

In today’s post we look at exactly what NOP is and what it does, we will review some of the Parkinson’s-based research that have been conducted so far, and we will look at what is happening in the clinic with regards to NOP-based treatments.

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Source: LUMS

On the surface of every cell in your body, there are lots of small proteins that are called receptors.

They are numerous and ubiquitous.

And they function act like a ‘light switch’ – allowing for certain biological processes to be initiated or inhibited. All a receptor requires to be activated (or blocked) is a chemical messenger – called a ligand – to come along and bind to it.

An example of a receptor on a cell. Source: Droualb

Each type of receptor has a particular structure, which is specific to certain shaped ligands (the chemical messenger I mentioned above). These ligands are floating around in the extracellular space (the world outside of the cell), having been released (or secreted) by other cells.

And this process represents one of the main methods by which cells communicate with each other.

By binding to a receptor, the ligand can either activate the receptor or alternatively block it. The activator ligands are called agonists, while the blockers are antagonists.

Agonists_and_antagonists

Agonist vs antagonist. Source: Psychonautwiki

Many of the drugs we currently have available in the clinic function in this manner.

For example, with Parkinson’s medications, some people will be taking Pramipexole (‘Mirapex’ and ‘Sifrol’) or Apomorphine (‘Apokyn’) to treat their symptoms. These drugs are Dopamine agonists because they bind to the dopamine receptors, and help with dopamine-mediated functions (dopamine being one of the chemicals that is severely in the Parkinsonian brain). As you can see in the image below the blue dopamine agonists can bypass the dopamine production process (which is reduced in Parkinson’s) and bind directly to the dopamine receptors on the cells that are the intended targets of dopamine.

Source: Bocsci

There are also dopamine antagonists (such as Olanzapine or ‘Zyprexa’) which blocks dopamine receptors. These drugs are not very helpful to Parkinson’s, but dopamine antagonist are commonly prescribed for people with schizophrenia.

Are there other receptors of interest in Parkinson’s?

Continue reading “Is there NOP hope for Parkinson’s?” →

Trazodo or Trazodon’t?

~ Simon ~ 11 Comments

“Repurposing” in medicine refers to taking drugs that are already approved for the treatment of one condition and testing them to see if they are safe and effective in treating other diseases. Given that these clinically available drugs have already been shown to be safe in humans, repurposing represents a method of rapidly acquiring new potential therapeutics for a particular condition. 

The antidepressant, Trazodone, has recently been proposed for repurposing to neurodegenerative conditions, such as Parkinson’s. 

In today’s post we will look at what Trazodone is, why it is being considered for repurposing, and we will review the results of a new primate study that suggests it may not be ideal for the task.

Opinions. Everyone has them. Source: Creativereview

I am regularly asked by readers to give an opinion on specific drugs and supplements.

And I usually cut and paste in my standard response: I can not answer these sorts of questions as I am just a research scientist not a clinician; and even if I was a clinician, it would be unethical for me to comment as I have no idea of your medical history.

In many of these cases, there simply isn’t much proof that the drug/supplement has any effect in Parkinson’s, so it is hard to provide any kind of “opinion”. But even if there was proof, I don’t like to give opinions.

Eleven out of every ten opinions are usually wrong (except in the head of the beholder) so why would my opinion be any better? And each individual is so different, why would one particular drug/supplement work the same for everyone?

In offering an answer to “my opinion” questions, I prefer to stick to the “Just the facts, ma’am” approach and I focus solely on the research evidence that we have available (Useless pub quiz fact: this catchphrase “Just the facts, ma’am” is often credited to Detective Joe Friday from the TV series Dragnet, and yet he never actually said it during any episode! – Source).

Detective Joe Friday. Source: Wikipedia

Now, having said all of that, there is one drug in particularly that is a regular topic of inquiry (literally, not a week goes by without someone asking about): an antidepressant called Trazodone.

What is Trazodone?

Continue reading “Trazodo or Trazodon’t?” →

Monthly Research Review – January 2018

~ Simon ~ 22 Comments

Today’s (experimental) post provides something new – an overview of some of the major bits of Parkinson’s-related research that were made available in January 2018.

In January of 2018, the world was rocked by news that New Zealand had become the 11th country in the world to put a rocket into orbit (no really, I’m serious. Not kidding here – Click here to read more). Firmly cementing their place in the rankings of world superpowers. In addition, they became only the second country to have a prime minister get pregnant during their term in office (in this case just 3 months into her term in office – Click here to read more about this).

A happy New Zealand prime minister Jacinda Ardine

In major research news, NASA and NOAA announced that 2017 was the hottest year on record globally (without an El Niño), and among the top three hottest years overall (Click here for more on this), and scientists in China reported in the journal Cell that they had created the first monkey clones, named Zhong Zhong and Hua Hua (Click here for that news)

Zhong Zhong the cute little clone. Source: BBC

Continue reading “Monthly Research Review – January 2018” →

Clinical trials: The Power of One

~ Simon ~ 12 Comments

As the age of personalised medicine approaches, innovative researchers are rethinking the way we conduct clinical studies. “Rethinking” in radical ways – think: individualised clinical trials! 

One obvious question is: Can you really conduct a clinical trial involving just one participant?

In this post, we will look at some of the ideas and evaluate the strengths and weaknesses these approaches.

A Nobel prize medal. Source: Motley

In the annals of Nobel prize history, there are a couple winners that stands out for their shear….um, well,…audacity.

One example in particular, was the award given to physician Dr Werner Forssmann. In 1956, Andre Cournand, Dickinson Richards and Forssmann were awarded the Nobel Prize in Physiology or Medicine “for their discoveries concerning heart catheterisation and pathological changes in the circulatory system”. Forssmann was responsible for the first part (heart catheterisation).

Source: Nobelprize

In 1929, at the age of 25, Forssmann performed the first human cardiac catheterisation – that is a procedure that involves inserting a thin, flexible tube directly into the heart via an artery (usually in the arm, leg or neck). It is a very common procedure performed on a daily basis in any hospital today. But in 1929, it was revolutionary. And the audacious aspect of this feat was that Forssmann performed the procedure on himself!

And if you think that is too crazy to be true, please read on.

But be warned: this particular story gets really bonkers.

Continue reading “Clinical trials: The Power of One” →

The Agony and the Ecstasy

~ Simon ~ 21 Comments

ecstasy

The contents of today’s post may not be appropriate for all readers. An illegal and potentially damaging drug is discussed. Please proceed with caution. 

3,4-Methylenedioxymethamphetamine (or MDMA) is more commonly known as Ecstasy, ‘Molly’ or simply ‘E’. It is a controlled Class A, synthetic, psychoactive drug that was very popular with the New York and London club scene of the 1980-90s.

It is chemically similar to both stimulants and hallucinogens, producing a feeling of increased energy, pleasure, emotional warmth, but also distorted sensory perception. 

Another curious effect of the drug: it has the ability to reduce dyskinesias – the involuntary movements associated with long-term Levodopa treatment.

In today’s post, we will (try not to get ourselves into trouble by) discussing the biology of MDMA, the research that has been done on it with regards to Parkinson’s disease, and what that may tell us about dyskinesias.

Carwash-image-07

Good times. Source: Carwash

You may have heard this story before.

It is about a stuntman.

His name is Tim Lawrence, and in 1994 – at 34 years of age – he was diagnosed with Parkinson’s disease.

_1169980_tim_lawrence_ecstasy300

Tim Lawrence. Source: BBC

Following the diagnosis, Tim was placed on the standard treatment for Parkinson’s disease: Levodopa. But after just a few years of taking this treatment, he began to develop dyskinesias.

Dyskinesias are involuntary movements that can develop after regular long-term use of Levodopa. There are currently few clinically approved medications for treating this debilitating side effect of Levodopa treatment. I have previously discussed dyskinesias (Click here and here for more of an explanation about them).

As his dyskinesias progressively got worse, Tim was offered and turned down deep brain stimulation as a treatment option. But by 1997, Tim says that he spent most of his waking hours with “twitching, spasmodic, involuntary, sometimes violent movements of the body’s muscles, over which the brain has absolutely no control“.

And the dyskinesias continued to get worse…

…until one night while he was out at a night club, something amazing happened:

“Standing in the club with thumping music claiming the air, I was suddenly aware that I was totally still. I felt and looked completely normal. No big deal for you, perhaps, but, for me, it was a revelation” he said.

His dyskinesias had stopped.

Continue reading “The Agony and the Ecstasy” →