If you care about public health, you’ve got to care about mental health. As a group, psychiatric disorders cause more social and financial cost worldwide than any other group of disorders—and they’re closely related to such major causes of disability and death as heart attacks, strokes, diabetes, and Alzheimer’s disease.
Check out this educational drama throwback, created by the International Health Board in 1920 on hookworm, and which one reviewer called “the best and only film of its kind on hookworm disease.”
Oh my gosh, this is so cool! The life cycle of the parasite is shown correctly (hookworm does indeed penetrate the skin, go from the heart to the lungs, then get swallowed to end up in the small intestine) and the disease is still diagnosed through examination of a stool sample. Though no longer a problem in the US due to advances in sanitation, it’s still an issue in poorer parts of the world, such as sub-Saharan Africa and southeast Asia.
An interesting note about hookworms: they and some related worms are currently being studied as a treatment for conditions like allergies and Crohn’s disease. The idea behind this is that humans coexisted with parasites for so much of history that without them, the immune system tends to malfunction. Clinical trials have been going for a decade or so, with some promising results.
Yesterday I got back from a trip to Yellowstone where I had the opportunity to take photos of some really interesting microorganisms! The beautiful coloration of the Morning Glory pool here is due to billions of thermophilic (heat-loving) organisms. The first of these were discovered in 1965, living happily in the park at temperatures around 82 to 88 degrees C, and about a year afterwards a particularly important one was isolated—Thermus aquaticus. Two decades later, T. aquaticus would serve as the source of Taq polymerase, the heat-resistant enzyme that made it possible to rapidly copy DNA through PCR, revolutionizing molecular biology.
How do microorganisms survive at temperatures like that? Their main challenge is keeping their structures from coming apart, so many have cell membranes and proteins with higher levels of molecular bonding than usual. Their DNA often has more guanine and cytosine than adenine and thymine—this is because G and C stick together with three hydrogen bonds, while A and T only use two.
These organisms also may account for the possibility of damage by having multiple chromosome copies on hand and cleaning up mRNA (which is ‘read’ by cellular machinery to make proteins) quickly, before it has the chance to start getting messed up. If temperatures get really bad—above what an organism likes—many produce heat shock proteins. These work as molecular chaperones, making sure that other proteins fold correctly and don’t assume forms that aren’t functional.
It’s worth noting that these organisms are thought to be similar to early forms of life, especially because many deal with additional challenges that were found in ancient environments, such as high pressures, high salt content and lack of oxygen. In this way, they can serve as a neat window to the past.
Photo is mine, information is from here.
Oral manifestations of childhood illnesses
1. Oral thrush - Caused by the Candida fungus overgrowing on the mucous membranes of the mouth. Also known as candidiasis when it occurs elsewhere on the body (such as vaginal candidiasis).
2. Varicella - Chicken pox. Have you ever had chicken pox in your mouth? It’s awful.
3. Stomatitis herpetica or Aphthosa [Herpetic stomatitis] - Caused by the same herpes infection of the mouth that causes cold sores, but blisters and mild ulceration can occur. This condition usually occurs when the child first contracts Herpes simplex I.
4. Stomatitis ulcerosa or Scorbutus - The oral manifestation of scurvy in children. The bone weakness, dry mouth, and immune dysfunction in scurvy often causes tooth weakening, loosening, and extreme gingivitis.
5. Follicular tonsillitis - The “standard” childhood tonsillitis, with infection of the palatine tonsils. If the infection doesn’t subside, removal of the tonsils is still the most common treatment.
6. Diphtheria - There are many oral manifestations of diphtheria, including “pseudo-membranes” covering the trachea, severely impairing breathing. The exotoxins exuded by Corynebacterium diphtherium can also cause thick, thrush-like patches in the pharyngotrachea.
Pediatrics: The Hygienic and and Medical Treatment of Children. Thomas Morgan Rotch, 1901.
Cool! An 1897 version of this book is freely available online.
Many ideas have left the world of science and made their way into everyday language — and unfortunately, they are almost always used incorrectly. We asked a group of scientists to tell us which scientific terms they believe are the most widely misunderstood. Here are ten of them.
Man, there are a lot of my pet peeves in here!
Nice infographic from the CDC! #4 is particularly good advice this time of year.
(And yes, you can in fact find those inspection records in many US states if you’re curious. They’re a bit haphazard and it looks as though restaurants are handled at the county level, but I was able to look up the grocery stores in my area through my state’s database.)
I’ve seen this story circulating lately, and being both a nerd and a skeptic I immediately wondered: if the virus did take care of the tumor cells, how on Earth did it do that?
Measles virus mostly replicates in places like the lymph nodes and spleen, which contain many immune cells. In order to replicate, it attaches to the outside of a cell, sends its RNA and some proteins into the cell, and uses the cell’s machinery to read the RNA and make new virus proteins from it. The newly put-together viruses then bud out of the cell. The cell may end up dying due to the virus infection, either through apoptosis (being triggered to self-destruct to try and stop the spread of the virus) or the messier process of necrosis (falling apart due to damage.)
The measles vaccine contains weakened (live attenuated) measles virus.The patient that showed great improvement in the study probably did so because her cancer was a myeloma—one where antibody-producing immune cells replicate uncontrollably. Because her immune system was suppressed, the measles virus naturally targets those kinds of cells, and the version of the virus used in the study had actually been genetically modified to help it go after cancer cells, it makes sense that the virus could’ve done a good job of destroying them.
Should we get excited about this study? I think it’s very interesting, but a single case doesn’t mean much in science. We’ll have to wait and see how the large clinical trials pan out.
If you’ve ever taken a developmental biology course, you’ve probably come across at least one quirky gene name—Sonic Hedgehog, so named because a mutation in it makes Drosophila fruit flies look spiny. There’s actually quite a few cleverly dubbed genes in the literature, including these gems:
- "Glass bottom boat": causes fly larvae to become transparent.
- "Indy": stands for “I’m not dead yet!”, a reference to the scene in Monty Python and the Holy Grail. Causes flies to live twice as long as usual.
- "Ken and barbie": males and females with a mutation in this gene lack external genitalia.
- "Limo": its product is involved in protein transport.
- "Ring": stands for “really interesting new gene,” because the scientists who discovered it had no idea what it did yet.
- "Superman": in the plant A. thaliana, individuals with a mutation in this gene have extra stamens (male genitals) in their flowers. There is also a variant of this gene called “clark kent” and a gene that suppresses “superman” is named—of course—“kryptonite.”
- "Tinman": flies with a mutant form of this gene lack a heart.
- "Yippee": so named because that was the reaction of the graduate student who managed to clone it.
I think my favorite, shown in the picture above, has to be "faint sausage," namely because I have absolutely no clue what that is supposed to mean (it apparently codes for a protein that aids in establishing nerve pathways.)
As amusing as these names are, they can be awkward when their homologues in the human genome are shown to play a role in disease (how do you tell a patient that their “Pokemon” mutation has caused their cancer?) For this reason and the sake of practicality, more recently discovered genes tend to have more systematized and bland names, though most of the silly ones are still in use.
Source: The New York Times