Friday, January 30, 2009

Fuck Ratzi, you really had to go there?

As an ex-Catholic, I still feel embarrassed each time the Church is caught with its pants down. Unfortunately, that seems to be quite often nowadays.

So which of the current idiotic moves I'm ranting about? Ratzi's reinstatement of bishops that are Holocaust denialists. Here is a video, taken just last week, of Bishop Richard Williamson.

WTF Church? What's next, the Church endorsing goecentrists, or denying that the current genocides exist?

Wednesday, January 28, 2009

The cruelty of reality

This is where I need to be right now. It's approximately 20 minutes away from my mom's house.

And this is where I am:

Not Pleased.
Posted by Picasa

On Pins and Needles: Parenteral Injection

There are three major routes of parenteral administration.
  • Intrevenous
  • Intramuscular
  • Subcutaneous
This will be a quick summary on the important aspects to consider in each type of injection.

First of all, how does drug absorption happen in each case?

In subcutaneous and intramuscular sites, absorption occurs by diffusion from the drug deposit to plasma. The absorption rate depends on the area of the capillary membranes absorbing the drug, and the solubility of that drug. When you administer a drug intravenously, you circumvent all the factors relevant to absorption.

Intravenous Administration

This method permits controlling drug delivery with an accuracy and immediacy not possible with any other procedure. It also permits the adjusting of drug dosage according to patient response, for example with anesthetics.
This the best, and many times the only method for administering irritating substances, since blood vessel walls are relatively insensitive, and the drug is greatly diluted by the blood.

There are also downsides to this, of course.
  • Unfavorable reactions may occur, since you can obtain high concentrations of the drug in your blood and tissue quickly. It is reccomended that you administer the drug slowly, by infusion, rather than rapid injection, and that the patient's response should be monitored closely.
  • Once you inject it there is no going back.
  • Drugs that are in an oily matrix, precipitate some of the blood components, or screw up your red blood cells should not be administered by this route.
Subcutaneous Administration

This method is very often used. However, keep in mind it only works with substances that are not irritating to the tissue. If not, you run the risk of horrific pain, necrosis, and tissue sloughing.
The drug absorption rate using this method is rather slow and constant - making it able to provide a sustained effect.

There are some nifty tricks that can be used to vary the rate of absorption of the drug. A good example is insulin delivery. A suspension of insoluble insulin will slower absorbed slower in this method than the soluble preparation of insulin. You can also add a vasoconstrictor to the drug to make the capillaries around it absorb the drug slower.
Some hormones are administered subcutaneously in a solid pellet form. Absorption of these preparations occurs over a period of weeks or months.

Intramuscular Administration

Drugs in aqueous solutions can be absorbed by this method quickly. However, the absorption rate can vary depending on the blood flow to the injection site. Absorption can be modulated by massage, local heating, or exercise. You can slower the absorption of a drug administered intramuscularly by putting it in an oily matrix or in suspensions. This is done often with antibiotics.

A good example of blood flow modulation would be injecting insulin and running. If you inject the insulin to your thigh and then run, you'll probably get a sudden drop in blood sugar. The increase of blood flow to the leg due to running causes an increase in absorption. Injecting in the abdominal wall or arms before jogging could decrease this drastic drop in sugar levels.

The amount of fat covering the the muscular tissue is also important. When we woman are injected in our butt, for example, we absorb the drug slower than males because we tend to have more subcutaneous fat there than the men, and fat is relatively poorly perfused (fatty tissue doesn't have many blood vessels). In very obese or emaciated patients drug absorption can exhibit unusual patterns in both subcutaneous and intramuscular administration.

Monday, January 26, 2009

I'd like to save my boobies, kthnx

I come from a family of huge, luscious boobies, and breast cancer. Thankfully, my grandma does breast cancer surgery, and along with my GP monitors my screenings.
However, a family propensity for Estrogen Receptor positive (ER+) tumors (my dad's 2 sisters and 2 of his cousins have already dealt with those) is not the only danger.

My environment is full of estrogen receptor agonists (an agonist is any molecule that binds to a receptor and elicits a response) that can increase my chances of getting one of those tumors. So I've been, slowly but surely, removing all the ER agonist containing stuff from my life.

  • I don't reheat anything in plastic - Plastic is made flexible by adding small molecules like phtalates and Bisphenol A. These are released if the plastic is heated, cracked, or if a liquid remains in it for quite a while. The solution: bowls and containers made of glass, food-grade stainless steel, or lead-free ceramics.
  • I am phasing out my cosmetics and personal care products (shampoos, conditioners, face and body wash, etc.) that contain parabens (like methyl parabezoic acid), placental extracts, or benzophenons. I have to give up the St. Ives apricot scrub and am not pleased.

For those of you equally concerned about reducing the risk of brest cancer, Cornell's Sprecher Institute has written a very nice article explaning the research done to ascertain this. They have videos explaining things too, but I have no idea how to embed them here. Go watch!

Sunday, January 25, 2009

Johny lost his friend

Mr. octopus went dacapitatey.

Saturday, January 24, 2009

The evils of deer

I have a thing against deer. Sure they're cute, when they're not plotting to kick you and give you Lyme disease when you're down!

Once, I was jogging with a friend of mine through an incredibly cute area. It has a tiny creek and behbeh bunnies jump about, cute squirrels frolic, there's songbirds all over the place, and there's always deer and their cute behbehs too - and it was Spring!!
So anyways, we were running, and gossiping, and cooing at the behbeh bunnies and we passed some deer at the other side of the creek. We cooed and moved on. And then we went for the second loop, and the deer were on our side.
The males started coming towards us - flicking their tales and acting all macho- so ran like crazy bitches - fearing we would have to run into someone's apartment screaming for safety. Lesson learned.

I have never trusted those cute bastards since, they had to be plotting something, right? And then I saw more evidence of their evil plotting:

Be afraid. Be very afraid.

Posted by Picasa

Friday, January 23, 2009

And he does it!!

Bringing yet again extreme awesome to the table, President Obama ended the global gag rule today.

This is me with my happy, happy uterus:

Thursday, January 22, 2009

Let's talk about Oral

The most common way to get a drug into the system is oral administration. It's the safest method, it's the cheapest, and the most convenient. However, sometimes this method is inadequate. It can be that the drug is destroyed by the high acidity of the pH, or by any of the digestive enzymes. Sometimes the drugs can irritate the gastrointestinal mucosa and make you throw up the medication. The absorption of some drugs can become irregular when accompanied by food or other drugs. And on top of that enzymes of the intestinal flora, mucosa, or from the liver can metabolize some drugs before they even get into your bloodstream.

So what regulates how much drug can be absorbed by the GI tract?
  • For starters the rate of dissolution of the pill, if taken in pill form.
  • The surface area for absorption - for example the stomach's surface area is small and covered by a thick mucous layer, while the villi in the upper intestine give it a large surface area that's able to absorb a drug better.
  • The pKa of the drug and its lipid solubility - Different areas in the GI tract have different pH, and you need to get the drugs through the membrane barriers into the blood plasma.
If the drug can be digested by gastric enzymes it can still be ingested as a pill if coated in a manner that avoids dissolution in the acidic environment of the stomach. This has a potential drawback; the coating may resist being dissolved and your body won't absorb most of the drug.

Controlled Release

The goal of this type of preparation is to produce slow, uniform absorption of the drug for 8 hours or longer. This is cool because the patient can take less pills (making it easy to comply with treatment), therapeutic effects can be maintained overnight, and you decrease the incidence of undesired effects because you avoid the peak of drug concentration the bloodstream that occurs when you use immediate-release dosage.

Of course not everything is unicorns and rainbows - there are several drawbacks. There is greater variability between patients on the systemic concentration of the drug. Another problem is that if the controlled release mechanism fails, and all the drug can be released at once. Since the amount of drug in the controlled release preparation is higher than the drug amount in immediate release preps, this "dose-dumping" can result in drug concentrations high enough to cause toxicity. Controlled release is best used with drugs that have a short half-life (<4>

Sublingual Administration

Your oral mucosa can also absorb drugs, especially if they are nonionic (has no positive or negative charges) and highly lipid soluble. Nitroglycerin is a perfect example:*Those plus and minus signs are partial charges, not formal charges, and arise from the electrons in those "tips" of the molecule liking the 2 Oxygens (O's) better than the Nitrogen (N's) and spending more time (in average) with the O than with the N.

Nitroglycerin also has various things going that makes it an awesome candidate for sublingual administration:
  • It's very, very potent. You only need to absorb a few molecules of it for it to have a therapeutic effect.
  • The mouth's veins drain into the superior vena cava, and thus goes straight to the heart, bypassing the hepatic first pass metabolism.
Rectal Administration

This is very useful when the patient is unconscious or is vomiting. About 50% of the drug absorbed through the rectum will bypass the liver and thus you loose less drug to first pass metabolism than with oral administration. On the down side, rectal absorption absorption can be irregular and incomplete, and lots of drugs can irritate the rectal mucosa.

*I have no idea how I resisted making many, many puns.

NEXT: On Pins and Needles: Parenteral injection

On drugs and getting to their targets

This will be a small intro to pharmacology. My goal is that after I finish this small series I can know the material well enough to be able to explain it to a layperson, and you guys can get some basics on what happens after you ingest any drug. Please ask questions, I will be grilled in my exam by the brilliant (and kinda intimidating at this moment) group I chose to be my committee.

First of all, what is a drug? You can consider a drug any substance that binds to some tissue in your body and produces an effect. So yes, a *lot* of things we ingest can be considered drugs.

Today, I'll write mostly about pharmacokinetics, in other words about what the body does to a drug. What does it do?

A - Absorption - is the movement of the drug from the site of administration to blood circulation
D - Distribution - is the process of diffusing or transferring the drug from within the vascular system to the rest of the body tissue.
M - Metabolism - is the chemical conversion or transformation of the drug into compounds that are easier to eliminate
E - Excretion - is getting rid of the drug and/or its metabolites via renal, pulmonary, or biliary processes.

These processes all have one thing in common- they involve the drug passing through cell membranes. In order for us to understand what's going on, we have to know the characteristics of both the drug and the cell membrane.

Let's talk a little bit about the cell membrane.

Take a look at the right end of the cartoon. Thephospholipid bilayer is the main component of the membrane. Phospholipids are a type of organic molecule that have water-hating tails (that touch each other in the middle of the bilayer), and water-loving heads (in the outside of the bilayer).

Since the middle of the membrane is hydrophobic it likes oily, non-charged compounds mostly. Charged or highly polar molecules would have a hard time passing through that, since they tend to be soluble in water. This membranes are also very flexible and fluid, and have a high electrical resistance. There are several proteins embedded in that membrane that transport molecules from one side to the other, among a lot of other things.

So if we want a drug to cross this membrane we need to know a few characteristics that can help or hamper its crossing.
  • Molecular size - Is it too big to pass through the membrane by passive diffusion across a concentration or electrochemical gradient?
  • Molecular shape - Can it be "grabbed" by one of the many molecules that have transporter proteins in the membrane? Can it be recognized by one of the transporter proteins by itself?
  • Degree of ionization- Depending on the pH of its environment some areas of the molecule can acquire or loose a hydrogen atom. The number of electrons in that end changes, and with that the polarity of the molecule.
  • Relative lipid solubility - like dissolves like. The more polar a thing is the more likely it likes water soluble and not lipid soluble.
  • Binding to tissue proteins - Here's where the tricky part starts. You'd like it to be able to bind to the specific receptors you want to have an effect on, but chances are it will also bind elsewhere.
Next, how are drugs distributed in the body, and more details about ADME.

If this is what a President sounds like, sign me up!

I know, I know that what's on paper is not done yet, but after 8 years of this:

"The most basic duty of government is to protect the life of the innocent. My Administration has been committed to building a culture of life by vigorously promoting adoption and parental notification laws, opposing Federal funding for abortions overseas, encouraging teen abstinence, and funding crisis pregnancy programs. In 2002, I was honored to sign into law the Born-Alive Infants Protection Act, which extends legal protection to children who survive an abortion attempt. I signed legislation in 2003 to ban the cruel practice of partial-birth abortion, and that law represents our commitment to building a culture of life in America..."

We now have this:

"Reproductive Choice

Supports a Woman's Right to Choose: President Obama understands that abortion is a divisive issue, and respects those who disagree with him. However, he has been a consistent champion of reproductive choice and will make preserving women's rights under Roe v. Wade a priority in his Adminstration. He opposes any constitutional amendment to overturn the Supreme Court's decision in that case.
Preventing Unintended Pregnancy: President Obama was an original co-sponsor of legislation to expand access to contraception, health information, and preventive services to help reduce unintended pregnancies. Introduced in January 2007, the Prevention First Act will increase funding for family planning and comprehensive sex education that teaches both abstinence and safe sex methods. The Act will also end insurance discrimination against contraception, improve awareness about emergency contraception, and provide compassionate assistance to rape victims. "

More little good things to make one sleep at night.

Wednesday, January 21, 2009


So with the crackdown on commenting over at Jezebel, I will probably muse here about whatever happens over there more often. C'est la vie. ¿Qué se va a hacer?

Lovely family

Chez Brigit there are two humans and three cats. Here I show the fluffy side of this family:

Here's Ms. Mota. She came as a tiny and stealthily pregnant kitten. She had 5 more kittens soon afterward, of which 2 were adopted by us.

She is made of extreme cuteness (if I say so myself-ahem) and softness. She is also scared of strange humans.

Johny Walker- or Johny the cat with a baseball bat, takes *vocal* to new levels. He'll talk to you nonstop even while he's purring. He also opens my bedroom door and wakes me asking for food with nose kisses. Adorable bastard.

If you think that Ewok's gray belly is asking to be scratched it's because
Vets Beware: He has to be scratched all throughout the visit, so good luck checking out his pulse with his constant purring.
He's also known to manipulate vets into giving him all sorts of treats- even cheese- so be strong! Don't let Ewok's mind control powers get you.

Might as well get it over and done with.

Yet another night without feeling sleepy (damn you stress!).

I've been thinking these past few weeks about starting a blog. I'm preparing for my A exam -after much procrastination- and it seems like an appropriate place to escape -for my sanity's sake.
Also a rather good place to put basic pharmacology principles as I review everything I've taken. So bienvenue chez moi!