Rajesh Harrykissoon, MD

08/24/2025

👏

08/19/2024

Unlikely Hero: Cat P**p Parasite Delivers Brain Therapy

A brain-infecting parasite found in cat p**p promises to deliver therapy to the brains of humans.

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A parasite commonly found in cat f***s might become an unlikely ally in treating neurological disorders. Researchers have successfully engineered **Toxoplasma gondii (T. gondii)** to deliver therapeutic proteins directly to neurons in the brain. This could permit treatments for conditions like **Rett syndrome**, a rare genetic neurological disorder that primarily affects females and leads to severe impairments in language, coordination, and movement.

The study, published in **Nature Microbiology**, exploits T. gondii’s unique ability to cross the blood-brain barrier and remain in a host’s brain indefinitely. By genetically modifying the parasite, scientists at **Tel Aviv University** and the **University of Glasgow** created a vehicle capable of carrying specific proteins to targeted areas of the brain.

T. gondii, which infects about one-third of the world’s population, typically causes no serious symptoms in healthy individuals. Its relative harmlessness and robust survival mechanisms make it a prime candidate for drug delivery. In mice, the modified parasite successfully delivered proteins into cell nuclei, including **MeCP2**, a protein linked to Rett syndrome.

Dr. Jasmin Dao, a pediatric neurologist not involved in the study, explained the significance: “Using T. gondii to inject therapeutic proteins into brain cells presents a novel potential approach to treating neurologic disorder conditions caused by specific protein deficiencies.”

However, this approach is not without risks. Dr. Santosh Kesari, a neurologist, cautioned: “One concern is the parasite going awry and causing side effects in humans from inflammation, infection including encephalitis. The scientists will have to engineer the parasite with many safety features to get rid of it whenever needed.”

Nonetheless, by repurposing a common parasite into a precision delivery system, researchers may have found a key to unlocking more effective therapies for a range of brain-related conditions.



Reference: https://www.nature.com/articles/s41564-024-01750-6
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Toxoplasma gondii secretion systems can be engineered to deliver multiple large therapeutic proteins to neurons in vitro and in vivo.

04/18/2024

I've had multiple rounds of antibiotics. Why am I still coughing?

Antibiotics had no measurable effect on the severity or duration of symptoms in patients seeking care for lower respiratory tract infections.

03/27/2024

Drugmaker AstraZeneca said on Monday it would cap out-of-pocket costs for its inhaled respiratory products at $35 per month in the United States from June, following a similar move by rival Boehringer Ingelheim earlier in the month.

11/05/2023

Beer vs Sleepiness: which affects your brain the most

I hope we were able to take advantage of the fallback hour to get a few extra winks.

Not sleeping enough turning you into a monster? In one of our most popular episodes, we bring you the cutting-edge science that helps us understand why. And we sort through the fads to find out, what really works to get more ZZZs. We speak with lab coordinator Pam DeYoung, sleep researcher Dr. Brady...

11/02/2023

New 2023 Lung Cancer Screening Recommendations

If you are a current or former to***co smoker aged 50-80, you may be eligible for an annual CT screening.

Screening is meant to catch lung cancer at an early stage when it is still curable.

Assess your risk: https://shouldiscreen.com/English/lung-cancer-risk-calculator

Discuss your eligibility with your doctor.

Image source: https://rtmagazine.com/disorders-diseases/cardiopulmonary-thoracic/lung-cancer/new-lung-cancer-screening-guideline-expands-eligibility/
Recommendation source: https://doi.org/10.3322/caac.21811

10/29/2023

Is there a link between mass casualty and suicidality?

Perpetrators of mass casualty follow a cognitive progression from social marginalization to scapegoating to the mass casualty event itself. It is important to note that this is just a simplified model, and the actual cognitive process of a mass shooter can vary from person to person.

The perpetrators of mass casualty are, more often than not, suicidal. For simplicity, let's use mass shooters as a model.

Internalization: There's something wrong with ME

Mass shooters often feel socially marginalized and isolated. They may have experienced bullying, rejection, or other forms of social exclusion.

Mass shooters may come to believe that there is something fundamentally wrong with them. They may feel like they are different from everyone else and that they don't belong. This can lead to feelings of alienation and self-loathing.

Externalization: There's something wrong with YOU

Mass shooters may exist in a cycle of internalization for years if not decades until they make a cognitive shift to externalize their "understanding." They may come to believe that the people around them are the ones who are wrong, not them. Or, that others have made them the way they are. This can lead to feelings of anger and hatred towards others.

Externalization: Scapegoating others

Mass shooters may identify specific groups of people as scapegoats. These scapegoats may be based on race, religion, ethnicity, sexual orientation, or any other group affiliation. The mass shooter may believe that these scapegoats are responsible for their own problems and that the world would be a better place without them.

Externalization: Action

The mass casualty event is the culmination of the mass shooter's cognitive progression. The mass shooter carries out their plan to kill or injure as many people as possible.

Externalization: Su***de

Following the mass casualty event, the mass shooter may either commit su***de (or surrender to the authorities).

In order to commit a mass shooting you have to be committed to this being your final act. You go in wanting to either be killed, kill yourself, or spend the rest of your life in prison. And so you have to be completely hopeless and suicidal to do it.

Discussion:

It is important to note that the actual mass casualty event is step 5 of a 6-step process. This means there are four preceding steps that offer the opportunity to identify and intervene in order to abort this cognitive progression.

The first step, social marginalization, often begins early in life--in childhood or adolescence. Externalization is a key shift in cognition that is necessary for the process to progress.

Suicidality calculator: https://www.mdcalc.com/calc/10169/columbia-su***de-severity-rating-scale-c-ssrs

Read more: https://gimletmedia.com/shows/science-vs/emh53mv?utm_source=gimletWebsite&utm_medium=copyShare&utm_campaign=gimletWebsite

Crisis helpline: 988

If you or someone you know is experiencing a mental health crisis, you can call or text 988 to reach the crisis helpline.

10/23/2023

Basic health coverage could be provided to all Americans automatically, without raising taxes.

Fixing the U.S. health care system can seem like a herculean task. But the solution is “actually very simple,” according to MIT economist Amy Finkelstein.

09/30/2023

Judge gives Medicare go-ahead to negotiate drug prices.

I always thought it was odd that an insurance payer spending taxpayers' funds, Medicare, did not have a say so in their own budget.

Imagine if your own household ran that way--all trades and service persons unilaterally dictated what you would pay for any household good or service. And, you can't say no (much less negotiate back or comparison shop). With free access to your wallet, what sales behaviors might one predict?

Would it be surprising that the price for goods and services escalates to drain your wallet?

But, that's the very scenario Medicare has been under.

The US government is essentially an insurance company with an army:

Federal Budget
-Medicare and other social insurance: 75%
-National Defense: 15%
-All else: 10%

The sector with the largest expenditure of our tax dollars had zero say in the price it paid, until now.

A federal judge on Friday declined to block the Medicare Drug Price Negotiation program, meaning companies will have to play ball with the government for the time being. U.S. District Judge Michael…

09/16/2023

Here's the latest covid vaccination guidance from the CDC.

October through April of each year is respiratory viral season. Those with respiratory conditions and/or impaired immune systems may benefit from the following vaccines:

1) Covid
2) Influenza
3) RSV
4) Pneumococcal
5) TDaP booster

A good timeline for seasonal vaccines is to get inoculated before October 31st (Halloween).

CDC is posting updates on respiratory viruses every week; for the latest information, please visit CDC Respiratory Virus Updates.

05/16/2023

Should you get a coronary artery calcium test?

In the United States, it’s estimated that about half of people between the ages of 45 and 84 have atherosclerosis and don’t know it. Heart disease—which is associated with atherosclerosis— is the leading cause of death in the United States.

The United States Preventive Services Task Force (USPSTF) does not recommend coronary calcium artery scoring CTs for the general population. The USPSTF concluded that the benefits of coronary calcium artery scoring CTs do not outweigh the harms for the general population. The harms of coronary calcium artery scoring CTs include radiation exposure, false-positive results, and unnecessary follow-up testing.

The USPSTF recommends coronary calcium artery scoring CTs only for people who are at high risk for coronary artery disease (CAD). People who are at high risk for CAD include those who have a family history of CAD, a history of smoking, or other risk factors for CAD.

If you are concerned about your risk for CAD, talk to your doctor. They can help you determine if you are at high risk and if you should have a coronary calcium artery scoring CT.

What is a CAC Test? A CAC test, also called a heart scan.

02/20/2023

Not a new finding per se, but rather a new method of measuring balance using Nintendo Wii. The low-tech method of single leg balance has long shown a correlation of the duration of balance with cognitive function.

If your single – leg balance is shorter in duration relative to your peer group, you may be at increased risk for cognitive impairment. Single leg balance duration tends to decrease beyond age 40.

Other gait/stance observations correlated with health conditions :

-Wide-based gait
-knock-knee appearance
-Side to side wobble of head

In general, the heel strike as one walks should be in a straight line. If your heel strikes are wide apart, this may be a compensatory mechanism to stabilize one’s balance. The next time you take a stroll on a sandy beach, look back and see how your heel strikes align.

An acquired knock-knee appearance (valgus deformity) may be to preserve one’s balance as body weight increases. Basically, the lower legs will splay outwards at the knees as we become more top-heavy with weight gain. This confers unbalanced stress loading at the knee joint and accelerates arthritis onset.

As one walks, the vertex of your head (tiptop as if dangling from a string) should remain stable without side to side or back to front wobble. A side to side wobble correlates with an increased risk for hip arthritis.

Researchers have developed a new method that can predict a person's risk of cognitive decline based on how well they can balance.