Read and amusing quote from Dr. Freeman Dyson in the June 2008 issue of Discover magazine.
“I’m 84, so I’m definitely over the hill. If I were starting today as a scientist, I’d certainly study biology. I’d probably be much better at dng biology today than I used to be, because it is now much more of a theoretical subject. Now you can do biology pretty well with computers.”
So I was talking to someone today who needs a large supply of peripheral blood mononuclear cells from a single donor. The idea is that her team needed to ensure that the cells would perform in a consistent manner, without the variability that multiple draws from different individuals would produce.
I recommended this source of cryopreserved PBMC samples. This source uses a serum-free preservation technique that ensures high recovery rates, allowing multiple blood draws to be taken from the same donor over time.
One of her colleagues asked if HLA-typed samples could be obtained. I said, “Yes.” It felt good, knowing that I could recommend a solution for them.
This article here talks about how you can combine three types of bioassays to produce more data that can be possible with only a single one. This requires much less effort than would be required by performing all of these assays separately.
Synergy. What happens when two or more agents acting in concert create an effect that’s greater than what they can individually produce. Ya gotta love it.
According to this news article, there was a major rise in the use of ELISPOT assays during 2006.
I’d be interested in knowing what kinds of trends were observed during 2007. I strongly suspect that this trend continued at an exponential rate, especially with the increasing use of automated analysis tools. I’d also be interested in seeing whether there’s a comparable trend in the use of FluoroSpot assays (that is, fluorescent variants of the ELISPOT method). And what about the year 2008…?
I thought the following was really interesting.
Source: Spiewak R, Pietowska J, Curzytek K. Nickel: a unique allergen – from molecular structure to European legislation. Expert Rev Clin Immunol 2007; 3 (6): 851-859.
Abstract
Nickel is a unique, mysterious and troublesome chemical element. Its molecular structure (unfilled electron shell) determines the high-reactivity and multidirectional biological effects. Some authors classify nickel as trace element, although its biological role in animal and human metabolism remains unclear. Conversely, nickel possesses strong sensitizing potential: as many as 65 million Europeans may be allergic to nickel. In this article, we review chemical and biological properties of nickel, pathomechanism, clinical symptoms and diagnosis of contact allergy to nickel, epidemiology and risk factors. Finally, public health measures and legal regulations of the EU aimed at protecting the population from nickel allergy are discussed, with particular attention devoted to the ‘Nickel Directive’ 94/27/EC.
One of the need things about ELISPOT assays (or ELISA spot assays) is that they allow cell measurements to be made with extreme precision — even allowing single-cell resolution. This resolution is orders of magnitude higher than that reached via tetramer staining, intra-cellular cytokine, or ELISA assays. This is especially helpful in T cell assays, since antigen-specific T cells typically occur in very low frequencies.
How is such extreme sensitivity achieved? Because ELISPOT assays capture cellular secretions around a small region surrounding the productive cell. Being captured rapidly in the immediate vicinity of the cell prevents these secretions from being degraded, diluted, or captured by receptors on neighboring cells. It truly is a brilliant process. This makes the assay especially useful for measuring antigen-specific responses, i.e., you stimulate a sample with an antigen and see how many cells respond.
I miss going to Mark’s Ark, this pet store that I used to frequent. The people were generally nice, and their selection of animals was really great. I just loved to watch the children looking around at the creatures in their shop. (I wish they had a more extensive fish selection, but with their limited space, they did pretty well.)
Oh, and I thought that Julie, one of their sales people, was pretty darned cute. Extremely cute.
Pinktoe tarantulas are great. They’re docile, and if they have a sufficiently large cage, you can keep more than one of them together.
For whatever reason though, I’ve had a hard time keeping them alive. Apparently, I don’t give them quite the right moisture levels. This is a pain, as I don’t have time to monitor their cages all the time. In addition, feeding them can be a challenge, due to their arboreal nature.
They’re delightfully docile, though.
I remember that in elementary school, our class would occasionally receive free samples of Colgate toothpaste. I also remember that instead of taking the samples home, some of my idiot classmates would promptly decide to eat the stuff.
Even at that young age, I asked myself “Why?” The toothpaste was completely non-nutritive, and it didn’t even taste particularly good. Nor could I imagine why anybody would find this enjoyable. As far as I could tell, their motivation seemed to be “Because I can.”
It never even occurred to these people to first find out if eating toothpaste was safe or not. Now, I’m sure that some of them said, “Well, I’m still alive, aren’t I? Don’t be so uptight.” This completely ignored the possibility of any long-term or non-obvious deleterious effects though — and frankly, I think that even a nine-year-old should know enough about science and the real world to understand such hazards. Heck, even if they’re not particularly smart or well-read, they should at least have enough common sense to say “Wait a minute. This might not be safe.”
In fact, there are potential hazards associated with eating toothpaste. Fluoride is a common ingredient in toothpaste, but too much fluoride can be bad for your health. There has been some debate about how dangerous it can be; however, the consensus is that normal consumption of fluoridated water is not hazardous. The fluoride concentration in toothpaste is considerably higher, though. I don’t know how much toothpaste you’d have to consume to reach hazardous levels–in fact, I don’t know if anybody knows–but why take the risk for such a foolish and idiotic stunt?
I culled the following bit of information from this article on immunology assay methods.
You can recycle the supernatant used in an ELISPOT assay for use in ELISA testing. For example, the ELISPOT method allows one to detect specific cytokines in T cell monitoring. After that, the supernatant can be used in an ELISA assay to detect other secretions–other cytokines, for example, or maybe antibodies. ELISA assays thus allow researchers to squeeze additional information out of a sample with only a little extra effort, and without requiring additional blood draws.
Way cool. Later, I’ll talk about flow cytometry as well.
