If you’re a man and you live in Scotland do not drink tea. According to a BBC report >7 cups a day give you a >50% greater chance of developing prostrate cancer than “normal” tea drinkers. This was the result of a study over 37 years involving 6000 volunteers aged between 21 & 75 years of age. I’m surprised they didn’t choose whisky and/or beer (they have probably been checked at some point in distant past). This is in direct contrast to a National Cancer Institute report which suggests the opposite, at least for green tea.
What’s next I wonder, coffee is already on the black list, as well as fatty foods smoking, no doubt sex will also rear it’s ugly head in the list of cancer producing agents, water is also dangerous, fish swim in it and you can drown as well.
Wiki tells us the exact opposite to the results reported by the Glasgow study. Tea is actually beneficial for you in all sorts of ways.
So what’s in tea that makes it so harmful or so good for you? Well there is theanine and caffeine, making up about 3% of its dry weight up to 90mg per cup, depending upon the tea. Theanine moves across the blood brain barrier (quite distant from the prostrate) and has a synergistic effect with caffeine, high doses even providing a neuroprotective effect. Caffeine is a stimulant and the author of the Wiki page suggests that it may even have moderately protective effect against certain cancers.
There are also things like theobromine (or should it be...
Professor Rahul Sarpeshkar and colleagues at MIT have created an implantable fuel cell which relies on glucose as its fuel. The device could potentially be used as a power source for the computers needed to decode brain signals and manipulate prosthetic or perhaps paralyzed limbs. The article was published in PLos ONE.
There are many layers of cool in this story. Implantable glucose fuel cells have been invented before – back in the 70s – but contained enzyme-based anodes which degraded over time and needed to be replaced. Because of this, implants like pacemakers rely on lithium ion batteries – which also drain over time, but have a much longer lifespan. This design utilizes a platinum anode to oxidize glucose ultimately to gluconic acid, liberating 2 electrons. The cathode is a matrix of single-walled carbon nanotubes which reduce dissolved oxygen to water.
What strikes me as the coolest part of this story, the fuel cell is fabricated on a silicon chip and would be placed in the cerebralspinal fluid next to the brain. Platinum is already known for being fairly biocompatable, but placing the chip in the cerebrospinal fluid is beneficial as there are very few white blood cells in the CSF to trigger an immune response and potential rejection. The CSF contains roughly the same concentration of glucose as plasma, and is not predicted to consume enough glucose fuel so as to impair brain function.
To avoid short circuiting the...
Tonight, we make soap.
Matt over at Sciencegeist is organizing this blog carnival in an effort to reclaim the word chemical from the hands of ignorant people who blindly assume anything with ‘chemicals’ in it must be evil. This is not a moment too soon. I’m not exactly sure how the pendulum of public opinion swung from products being advertised as ‘Better living through chemistry’ to products being advertised as ‘chemical free’ (whatever that means). Soaps and other skin care/beauty products are certainly in the cross-hairs of the ‘chemical free’ crowd, but that’s not what I’m talking about today.
As the tallow renders, you skim off the layer of glycerin. If you were to add nitric acid, you got nitroglycerin. If you were to add sodium nitrate and a dash of sawdust, you’d have dynamite.
Sincere apologies for not writing regularly on the blog. My chemical career trajectory has recently taken an unplanned turn and has required me to learn an other new skill set to succeed. I am now the CTO for my PI’s biotechnology company, which sounds cool to say, but isn’t as much fun as discussing science. My duties have now switched to making sales pitches, finding investors, writing SBIR grants, and making sure projects are progressing, I still found a little time to sneak in some science experiments last week. So lets get down to pretty pictures.
I xenografted some mice in the lab a few weeks ago for a collaborative project that didn’t go anywhere. Last week, the tumors grew past the point of no return, and at UCLA once they hit 1.5 cm we are mandated to euthanize the mice. Last week I also found myself with a little extra time and with the help of a fellow chemist we made some fluorescent molecules that “potentially” have interesting tumor targeting properties. As I had mice with tumors too big, and molecules that target tumor cells, I pretty much said what the hell and injected this molecule into the mice (Yes, I had ARC approval). A picture of the results is below with the control mouse on the left, injected mouse on the right. Areas colored red have the highest intensity, areas colored dark blue have the lowest intensity.
It is a result like this that makes me happy for working at the crossroads of Chemistry and Biology. I love being able...
This is Prilosec OTC (omeprazole, also marketed as losec, antra, gastroloc, and a number of other names in other countries):
This is Nexium (esomeprazole, also marketed as sompraz, zoleri, lucen, etc):
Did you note the difference? I’ll give you a second to look again.
Omeprazole was brought to market by (what is now) AstraZenica in 1989. It is used in treatment of gastroesophageal reflux desease (GERD, commonly known as acid reflux). It is a proton pump inhibitor which works by blocking the production of gastric acid by parietal cells. It was a blockbuster drug. In the year 2000 alone, omeprazole made $6.26 billion. But in 2001, omeprazole’s patent was set to expire. AstraZenica needed something to fill their pipeline, so they looked at their data for omeprazole.
Omeprazole is an example of a little-known class of chiral molecules where the stereogenic atom is not carbon. We typically think of stereocenters with carbon as the central atom. But this is an example of a stereogenic sulfur atom (in case you’re wondering where the fourth ‘thing’ bonded to sulfur is, it is a pair of electrons. See the explanation of chiral sulfoxides for more information. Ellman’s chiral auxiliary is a good example of chiral sulfoxides in use). Omeprazole is a racemic mixture: an equal mixture of (R) and (S) enantiomers.
In looking at their data on omeprazole, they noticed that the (S) enantiomer was more potent than the (R) enantiomer...
Vincent RotelloSarit Agasti and Chae Kyu Kim
In a new AOP from Nature Chemistry, Vincent Rotello’s group report a new way of killing cells. There system uses gold nanoparticles (AuNPs) as the core, and attached to the core is a diaminohexane group. The diaminohexane fragment is sheathed from the cell by cucurbituril (CB).
Once the AuNPs enter the cell they can be triggered to expose its cytotoxic diaminohexane appendages by introducing 1-adamantylamine (ADA); ADA outcompetes the diaminohexane for CB.
The paper shows some very nice chemistry and it does a nice job selling the point that their gold nanoparticles are toxic to cells. However, I am worried when they say they are “exploring this strategy in vivo…” as the current generation of their system seems indiscriminate. But, I always enjoy being proven wrong.
Link to paper: Recognition-mediated activation of therapeutic gold nanoparticles inside living cells
Other recent papers by Vincent Rotello
Is high fructose good for you or bad for you?
How many of you said bad? Leads to obesity, right? Gotta stay away from HFCS, right? That’s what ‘everyone’ says, right?
Consider: The sugar we call ‘table sugar’ is sucrose: a disaccharide: a molecule of glucose and a molecule of fructose (two monosaccharides) covalently bonded to each other. Sucrose is broken into fructose and glucose by enzymes within living organisms (like humans). Humans don’t use sucrose for energy, first we break it into glucose and fructose and metabolize the monosaccharides for energy. So we ingest sucrose, digest it to glucose and fructose, then use the monosaccharides for energy.
One molecule of sucrose becomes 1 molecule of glucose and 1 molecule of fructose. That means that sucrose is digested to a 50/50 mixture of fructose and glucose.
Consider: High fructose corn syrup is a straight mixture of unbonded glucose and fructose. There are two common types of HFCS: HFCS 55 and HFCS 42. HFCS 55 is ~55% fructose and ~42% glucose. HFCS 42 is ~42% fructose and ~53% glucose.
So what’s the difference?
Sucrose becomes a 50/50 mixture of fructose and glucose. HFCS 55 is a 55/42 mixture of fructose and glucose. Chemically, there’s no difference between fructose from sucrose and fructose from HFCS. Our bodies can’t tell the difference between fructose from sucrose or fructose from HFCS. We’ve been fretting so much about a 5% difference...
My postdoctoral research has just begun (started 1.5 months ago) and it will heavily rely on using mice. Thus far I have imaged, dissected, injected, xenografted, castrated, you name it and I’ve already done it or will be doing it to mice. As chemists we are sheltered from the bloody side of science. Sure some chemists on the biological side may have done cell culture or a gel here and there, but most chemists don’t handle things that bite you while your injecting the nanoparticles you made to monitor the progress of the cancer you gave them weeks earlier. Because of this I will be making a series of posts tagged a Chemist Doing Biology chronicling my adventures into Biology.
Brief background: I am a Chemist not a Biologist, my PhD was equal measures of nuclear/radio-chemistry, materials chemistry, organic synthesis, and electronic circuit design (sigh). My new research group is all chemists even though we are in the Pharmacology department. My first task in the group, take the graduate student’s Gd-encapsulated nanoparticles and inject them into mice. Then extract the lymph nodes and get ICP-AES data. A daunting task for a chemist to accomplish, especially with no biologists in the group or anyone having in vivo experience.
Fortunately, I found a happy biology graduate student willing to take her research time to teach me how to do the injection/dissection of the poor mice. When the day arrives, the chemistry graduate student and I whisk the biologist down...