Body hair
How are hairs in apes and humans diffrent?
Human hair are fineness and have other functions than their counterparts in more hirsute species (insulation, colouration, signalling or camouflage).
What did Ms Dean and Dr Siva-Jothy discover about human body hairs?
They discovered that human’s fine body hairs are as an alarm system. Fine body hairs are to alert their owner to creepy crawlies like bed bugs, which might be intent on biting them. The hair give the owner more time to react before he is bitten.
How were volunteers prepared for the experiment carried out by Ms Dean and Dr Siva-Jothy?
Each had a patch of skin on one arm shaved, marked with a pen and surrounded by petroleum jelly (to fence the bed bugs in), and a commensurate patch on the other marked and surrounded, but not shaved.
What happened when a bug was on a hairy patch?
When the bug was on a hairy patch it was detected every four seconds. The bugs seemed to find it harder to locate a good spot to bite when they were surrounded by hair.
What happened when a bug was on shaved skin?
When it was on a shaved patch, more than ten seconds elapsed between detections.
Cancer Drugs
What is the role of the TRAIL protein in cancer cells?
TRAIL protein is produced by damaged cell and binds to receptors on its surface. They are a signal for the immune system to break down the damage cell and recycle its parts to feed healthy ones.
What hopes did researchers attach to the TRAIL protein after its tumor-suppressing ability was discovered?
They hoped that TRAIL would do away with the debilitating sideeffects associated with traditional treatments like radio- or chemotheraphy.
Why did the synthetic version of the TRAIL protein turn out to be ineffective in fighting tumors?
It’s because the synthetic version of the molecule after injecting into the patient’s body provoked only a limited immune response in a handful of cancers.
How does TIC10 trigger the body’s immune response to cancer?
Molecules accumulate in cancer cells and activate a protein FOXO3a, which binds to DNA and flips on many biological pathways, including TRAIL mechanism that lead to the immune system alerting infammation.
Epigenetics and Health
What does the term 'epigenetics' refer to?
It refers to the regulation of gene expression by the chemical modification of DNA, or of the histone proteins in which DNA is usually wrapped. This modification is the addition of methyl groups (a carbon atom and three hydrogens) to the DNA and of acetyl groups (two carbons, three hydrogens and an oxygen) to the histones. Methylation switches genes off. Acetylation switches them on.
How is the notion of epigenetic inheritance different from the classic approach to heredity?
There is an idea that epigenetics switches can be inherited. Some people see this as contrary to Darwinism, since it would permit characteristics acquired during an organism’s lifetime to be passed on to its offspring. The DNA sequence itself is not being permanently altered. Those epigenetic changes that are inherited seem to be subsequently reversible.
What did the study by Dr Rehan consist in and what did it show?
The study was of the intergenerational effects of nicotine. It showed that if pregnant rats are exposed to nicotine, not only will their offspring develop the asthma induced by this drug, so will the offspring of those offspring.
Why might epigenetic changes be compared to the biblical curse?
Biblical curse is that that the sins of the fathers or the mothers will be visited on the sons, even unto the third and fourth generations. And in case of epigenetic, acquired characteristics can be inherited.
Restarting hearts
How do television medical dramas differ from the real world?
On TV restart a stopped heart is always succeed, spectacularly and immediately. The real world is crueller: doctors manage to restart only about half of the hearts that stop in a hospital, and only about a sixth of patients will go on to survive long enough to be discharged.
What procedures are used to resucitate a patient with a heart attack?
A doctor summons a posse of helpers, who start zapping the patient, compressing his chest or administering adrenalin jabs.
What is the toughest decision faced by hospital staff?
One of the toughest decisions faced by hospital staff is how long to keep trying, and when to give up on a particular patient as a lost cause.
What did the paper in the Lancet magazine reveal?
A new paper, published in the Lancet, aims to provide some scientific backing for such decisions, but there are no official guidelines specifying how long doctors should keep trying to resuscitate flat lining hospital patients.
Why are some doctors reluctant to spend too long attempting to revive a patient?
One reason why doctors are reluctant to spend too long attempting to revive patients is that they worry about brain damage caused by prolonged lack of oxygen. A doctor considering whether to continue with chest compressions, for instance, must weigh any number of factors, from the patient’s age to other conditions he may be suffering from or the effects of drugs used to treat them. The presence of so many confounding factors makes it hard to assess the general effectiveness of any given treatment.
Synthetic Biology
1. What did Craig Venter and Hamilton Smith achieve in their laboratory and why may their work not convince everybody?
The two American biologists have made a bacterium that has an artificial genome and no ancestor. Their work may not convince everybody, because researchers had to use the shell of an existing bug to get that DNA.
2. According to the magazine, what two related developments in the past decade make the arrival of synthetic lifeforms inevitable?
First development is an extraordinary rise in the speed and fall in the cost of analyzing the DNA sequences. What once took years and cost millions now takes days and cost thousands. Databases are filling up with the genomes of every living organism.
Second development is faster and cheaper DNA synthesis. It will soon be possible for almost anybody to make DNA.
3. What are the upsides and downsides to the idea that it will be possible for anybody to dabble in synthetic biology?
Upsides – It’s good that soon everyone could get their own DNA. The more ideas there are, the better the chance some will prosper.
Downsides- Some biological inventions like guns and explosives could be breed by almost anybody and can be malicious.
4. According to some observers, why is open access to synthetic biology technology the best approach to counter the threat of creating artificial pathogens deliberately?
Thoughtful observers think that openness can avoid shutting out the good in a belated attempt to prevent the bad. The best way to oppose the villains is to have lots of heroes on your side. And when a problem arises, an answer can be found quickly. If pathogens can be designed by laptop, vaccines can be too.
Joys of parenthood
1. What did the experiments conducted by Sonia reveal?
Dr Sonia decided to study the existing literature and to conduct some experiments of her own. The results suggest parenthood in general, and fatherhood in particular, really are blessings, even though the parents in question might sometimes feel they are in disguise.
2. What is the World Values Survey?
World Values Survey is a first port of call. This is a project which gathers huge amounts of data about the lives of people all around the planet.
3. What problems did Sonia encounter with the WVS?
Sonia asked about 7 thousands Americans in four different years to four particular questions. These were: how many children the responder have? How satisfied he or she was with life? How happy he was? How often the thought about the meaning and purpose of life?
4. How did Sonia survey parents?
Sonia gave pagers to American volunteers aged between 18 and 94. She told them they would be paged at random, 5 times a day. When they were so paged, they were asked to complete a brief response sheet about how they felt, then and there. She didn’t tell them, why she was asking these questions.
5. What was the upshot of Sonia’s experiment?
The upshot was the same as her findings from the World Values Survey. Parents claimed more positive emotions and more meaning in their lives than non-parents. Further analysis revealed that this enhanced enjoyment came from activities which involved children rather than watching TV alone or cooking.
6. What evolutionary purpose may the joys of fatherhood serve?
Evolution has bolted into keep men in the family. If man can find willing volunteers, a man's potential to father an indefinite number of offspring might encourage him to stray from the bosom of his family.
The uses of Stem Cells
1. What are iPS cells and how are they obtained?
iPS cells are induced pluripotent stem cells. They are obtained by adding four activated genes to adult skin cells.
2. What use does AstraZeneca want to make of iPS cells?
They would buy human heart muscle, blood vessels, nerve cells and liver cells made from iPS. They want to use them to find molecules that encourage non-pluripotent stem cells to turn into mature tissue. They want also to use iPS cells to test drugs that have nothing to do with regenerative medicine.
3. What use did GlaxoSmithKline make of iPS cells?
They described an experiment in which it assaulted neurons derived from iPS cells with beta amyloid and tested the beta amyloid responded to hundreds of existing drugs.
4. How can disease development be explored using iPS cells?
iPS cells are derive from patients with specific ailments and then nudge the induced cells into becoming the type of cell afflicted by that ailment. Some researchers do this to explore how the disease in question develops and whether it succumbs to drugs.
Treating cancer
1. What advantage do drug-carrying nanoparticles have over chemotherapy in treating malignant tumors?
Drug carrying nanoparticles can be tailored to release their payloads only when the surrounding environment indicates that they are near a tumor, thus reducing collateral damage.
2. How does the body stem bleeding when it sustains an injury?
When the body sustains an injury, notification proteins are produced and they communicate with clotting agents in the blood. They round up platelets and fibrinogen. The fibrinogen turns into an insoluble fibrin, which traps the platelets and causes them to link up into a quilt that helps stop bleeding.
3. How does the drug delivery system invented by Dr Bratia and Dr von Maltzahn work?
Signalling nanoparticles would function like notification proteins, marking the location where action was required. Receiving nanoparticles would be recruited like platelets and they would deliver the drug.