1

Cells, Microbes & Viruses / Re: Why do hands need soap and regular washing but fruit just needs a rinse?

« on: 21/06/2017 17:08:06 »

I think when we wash fruit, we're more so concerned with removing and chemicals form the agricultural process (fertilizers, pesticides, herbicides) These are quite likely very water soluble and definitely not lipid-based which would require soap to adequately get rid of them.

2

Physiology & Medicine / Re: Does masturbation promote fertility?

« on: 21/06/2017 16:48:46 »

my understanding is that yes, it does (as long as you refrain within the 48hr period prior to copulation).  more importantly, it also reduces the risk of prostate cancer.

3

Physiology & Medicine / Re: Do genes and DNA respond to musical vibrations?

« on: 21/06/2017 16:46:49 »

I would assume that all of the physiological responses to music happen at the receptor signaling level.  These responses COULD conceivably lead to temporary changes in gene EXPRESSION, but not ACTUAL genetic alterations.  I suppose that in the case of EXTREME (and likely repeated) exposure to a certain stimulus like music, epigenetic changes could occur that would be more permanent, but the DNA itself would still be unaltered.

4

Physiology & Medicine / Re: Why hasn't evolution selected out painful childbirth?

« on: 21/06/2017 16:42:57 »

great topic. I have a feeling everyone who has posted thus far hit the nail on the head.

5

Physiology & Medicine / Re: Does the brain multitask better in some people?

« on: 21/06/2017 16:39:41 »

Everything I have read supports the initial poster's comments that the human brain cannot physiologically focus on more than one thing at a time. But as we all know from daily life, and as the second poster points out, we the physiological inability to multitask doesn't prevent the functional act of multitasking (due to "switching" as noted in both posts, meaning that we basically operate similar to a PC running Windows 95).  In the end, its really a matter of semantics, and what you consider "multitasking".  When it comes to "functional" multitasking, I read an interesting study once that found there was very little difference between most individuals and their ability to functionally multitask, even though there was a large disparity in how people perceived their own ability to multitask.  That study (which I wish I could find now) found that the differences in one's confidence to multitask actually stemmed from differences in perception of who well one was performing the tasks they were performing.  Simply put, everyone's performance dropped when concentrating on multiple activities at once, but some people realized it (and claimed to have poor multi-tasking abilities)  while other people convinced themselves that they were still performing the tasks at a high level and therefore claimed to be excellent multi-taskers.  Just one study though, definitely not the end-all be-all in the field.

6

Guest Book / Re: Its been too long...

« on: 16/05/2017 16:25:47 »

Shall we all attempt to contact everyone who has been a major part of this place over the years and try to get everyone together?

I loved my last visit to the UK, but its bloody expensive over there!! You guys should make it a destination reunion, stateside.

7

Physiology & Medicine / Re: How does apple cider vinegar affect your pH levels?

« on: 16/05/2017 16:21:56 »

yes and no. technically, anything you put into your body affects the pH. however, most systems in your body (including your GI tract) are heavily buffered to prevent much of a change in pH from the addition of an acid or a base.  That said, at some point, you could overwhelm the buffering agents in your body, so I wouldn't recommend drinking gallons upon gallons of apple cider vinegar in one sitting.

8

Physiology & Medicine / Re: What cells are best to keep for DNA analysis if the person has died?

« on: 16/05/2017 16:18:16 »

A couple of notes about your question Paul:

-unfortunately hair itself doesn't contain DNA. if you just clipped some hair from her head, you probably don't have any.  However, if any of the hairs still contain the hair FOLICLE, then that's plenty.

-like chris said, you would want to preserve the sample somehow. The best way would be to purify the DNA and store it in a refrigerator, however, DNA is actually reasonably stable and you can do pretty high-quality analysis off of really crappy DNA samples, so simply freezing the hair for now would probably suffice, and even if its been keep unfrozen for sometime, it might still be useful (if it had the follicle).

-As far as how useful the information gleaned from DNA analysis might be....  that's a more difficult question. We can learn a lot from analyzing the DNA of large groups of people, looking for similarities and differences and comparing those to differences in those people's health record.  However, these analyses are not very straight forward as there are SO many variables to be considered. Since it is so easy to get someone's DNA (a hair sample, a blood sample, a cheek swab, even just some spit often times) its usually not a challenge getting a large collection of samples from people (unless you're looking for a group of people with a certain rare disease).  The challenge is in making useful findings from those samples. But there are people who do that every day and we are finding out more and more all the time.

-As far as your point about DNA from hair not being able to tell you much about her propensity for lung cancer, that is actually false.  All of the (genomic) DNA in your body is identical regardless of the type of cell, so I could take a skin biopsy from your butt cheek and it would tell me the exact same information about your likelihood of developing glaucoma or any other of your inherited traits as a cheek swab would. What it wouldn't tell me, is whether you mother was a smoker, or whether she lived in a city with lots of pollution, or any number of environmental factors that would greatly impact her health and likelihood of developing cancer.

Hope there is something informative and interesting in there for you.

9

Physiology & Medicine / Re: Why do we only get 2 sets of teeth?

« on: 16/05/2017 16:03:32 »

Karen, is your friend a shark by chance? 

10

Cells, Microbes & Viruses / Re: Is a donated organ eventually replaced by the new host's own cells?

« on: 12/05/2017 15:47:13 »

To be clear, I don't think a child would re-grow a whole hand either.

(also, after a careless incident in the kitchen last year, I can say from personal experience that adults can re-grow fingertips!)

11

Cells, Microbes & Viruses / Re: Is there a way to lyse both red cells and white cells but not lyse bacteria?

« on: 12/05/2017 15:44:19 »

I've never tried, so I don't have an exact protocol, but I think you're spot on with water.  Most bacteria hold up quite well in water, while WBCs should lyse quite rapidly.

12

Physiology & Medicine / Re: Have you ever had a Thunderclap Headache During Orgasm?

« on: 12/05/2017 15:40:41 »

I cannot BELIEVE this thread is still active 12 years later....

13

Physiology & Medicine / Re: What is the physiological function of lipid rafts?

« on: 12/05/2017 15:38:37 »

lipd rafts serve to sequester different signaling complexes to different physical proximities in the cell.  For example, if a cell needs to change shape, it is not enough to simply cue the signal for actin polymerization, the cell needs to dictate WHERE that actin polymerization is to take place.  By re-arranging the organization of various lipid species within its membrane structures, a cell can determine WHERE a given activity will take place. In the case of actin polymerization, some of the signaling proteins are attracted to a certain species of lipid and thus are sequestered to regions where this species has been concentrated and/or generated at a higher rate.  When these multiple signaling proteins come into proximity with each other (as a result of being recruited by the lipid rafts) they activate each other and actin elongation occurs at the precise spot where the lipid content was altered.

14

Physiology & Medicine / Re: Why do we only get 2 sets of teeth?

« on: 12/05/2017 15:31:48 »

If humans lived longer, or lost/damaged teeth at a higher rate, I would imagine that we would have evolved to replace teeth more than once during our lifespans. Give how we live, there just wasn't any/enough evolutionary pressure for more teeth than we have.

15

Guest Book / Re: Its been too long...

« on: 18/04/2017 20:13:16 »

There used to be a bloke just like ewe on the is forum ages ago !!!..hmmmmm !!!

Neil...  I have to ask, what is it with you British blokes and your "ewe" puns?  When my wife and I were on our honeymoon (oh yeah, I'm married now) we met a lovely couple from Yorkshire and have stayed very close friends with them since.  I've even been over to the UK for a visit a couple years ago (I kept an eye out for you the whole time, but no luck).  In any case, he always makes "ewe" jokes at me.  He even went so far as to print a custom T-shirt for me with an "ewe" joke on it. 

On second thought... perhaps you are him.

16

Physiology & Medicine / Re: Why don't scars disappear as tissue is replaced over time?

« on: 12/04/2017 18:00:03 »

I can say from my own research that we see an initial accumulation of senescent cells at the site of a healing wound/forming scar tissue, but these cells most definitely disappear over time (matter of weeks, at least in mice) indicating that the cells in that part of the tissue ARE being turned over, even if that structure of the scar remains.

17

Cells, Microbes & Viruses / Re: Could flu be transmitted sexually?

« on: 12/04/2017 17:47:06 »

Good points.  I should have considered the connectivity between the eyes and the nasal passages (and therefore respiratory system).

18

Cells, Microbes & Viruses / Re: How do the proteins not become this giant mess of tangled threads?

« on: 11/04/2017 15:27:46 »

Two factors that the original question failed to consider:

1) proteins fold AS they are being translated rather than waiting for translation to finish and then folding all at once.  Therefore, you don't have all these long strings of amino acids just hanging around.

2) While cells are very small and compact, proteins are even smaller, so they have a reasonable amount of room in which to translate and fold.

19

Cells, Microbes & Viruses / Re: Why is brain cancer so common?

« on: 11/04/2017 15:24:49 »

1:5000 isn't all that rare.  Given the prognosis for most brain cancers, I'd like better odds than that!

20

Just Chat! / Re: What is Trump's opinion about chemtrails?

« on: 11/04/2017 15:21:28 »

I'm guessing Trump is a huge fan of chemtrails.  If it weren't for crazy conspiracies like this, the radio shows from which his campign support swelled would have anything to discuss on a daily basis and would exist. If that were the case, he never would have gotten a sniff at the White house.