3 ms·

I know they did. If they had just stuck to the part about genetic tests, that'd be fine. It's the flowery language about how they're adapted to depths that woul

I know they did. If they had just stuck to the part about genetic tests, that'd be fine. It's the flowery language about how they're adapted to depths that would kill normal human beings that I was objecting to. They should have said that generations of divers have made these people have larger spleens which makes them marginally better at deep diving. But that's less dramatic and, presumably, gets fewer clicks.

nonbel 9y ago
It looks worse than that. In figure 1 of the paper[1] they only make a comparison between Bajau and Saluan populations. They show the "enlarged spleens" have volume of ~200 cm^3. However, if you look at humans overall, apparently even these "enlarged spleens" are much smaller than the average spleen: >"The mean splenic dimensions were ... 333.6 ± 116.1 cm2 in volume." https://www.ajronline.org/doi/abs/10.2214/ajr.184.1.01840045 https://www.ajronline.org/doi/abs/10.2214/ajr.184.1.01840045 [1] http://www.cell.com/cell/fulltext/S0092-8674%2818%2930386-6 http://www.cell.com/cell/fulltext/S0092-8674%2818%2930386-6 EDIT: They write: >"We made ultrasound measurements in two planes such that we were able to calculate spleen volumes according to the methodology outlined in Yetter et al. (2003)"[1] So lets look at Yetter 2003 for their spleen volumes, in table 2 it shows they are >500 cm^3 on average: https://www.ajronline.org/doi/abs/10.2214/ajr.181.6.1811615 https://www.ajronline.org/doi/abs/10.2214/ajr.181.6.1811615 So it looks like these "super spleen divers" actually have relatively small spleens...
- geon 9y ago
  Is their body mass significantly lower than the overall human population?
  - nonbel 9y ago
    If so, then the relevant measure should have been spleen volume to body mass ratio...
- defen 9y ago
  The patients in the Yetter paper were all being evaluated for liver disease, so their measurements might not be what you want to use as normal.
  - nonbel 9y ago
    Thanks, looking closer at the Yetter paper: >"Normal cadaveric splenic volumes reported by Loftus et al. [8] are 26–250 cm3 with a mean volume of 110 cm3 and an SD of 70 cm3. Henderson et al. [19] reported a normal splenic volume of 219 cm3 as calculated from axial CT acquisitions." So an average of 219 cm^3 according to axial CT is still larger than what is seen here. I'm not sure about the cadaver spleens, do they shrink? The Loftus paper only reports maximum length vs actual volume so we can't see that direct correlation. Some other papers report 184 cm^3 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4549594/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4549594/) and 214.6 cm^3 (https://www.ncbi.nlm.nih.gov/pubmed/9038125 https://www.ncbi.nlm.nih.gov/pubmed/9038125)
darkerside 9y ago
Yeah, lines like this are ridiculous. “I would think, as morbid as it is, that if they didn’t have this, it would kill them,” she said. Yeah, and by a similar leap of logic, if we didn't have two legs, we'd flop around on the land like fish.

nonbel 9y ago

It looks worse than that. In figure 1 of the paper[1] they only make a comparison between Bajau and Saluan populations. They show the "enlarged spleens" have volume of ~200 cm^3. However, if you look at humans overall, apparently even these "enlarged spleens" are much smaller than the average spleen: >"The mean splenic dimensions were ... 333.6 ± 116.1 cm2 in volume." https://www.ajronline.org/doi/abs/10.2214/ajr.184.1.01840045 https://www.ajronline.org/doi/abs/10.2214/ajr.184.1.01840045 [1] http://www.cell.com/cell/fulltext/S0092-8674%2818%2930386-6 http://www.cell.com/cell/fulltext/S0092-8674%2818%2930386-6 EDIT: They write: >"We made ultrasound measurements in two planes such that we were able to calculate spleen volumes according to the methodology outlined in Yetter et al. (2003)"[1] So lets look at Yetter 2003 for their spleen volumes, in table 2 it shows they are >500 cm^3 on average: https://www.ajronline.org/doi/abs/10.2214/ajr.181.6.1811615 https://www.ajronline.org/doi/abs/10.2214/ajr.181.6.1811615 So it looks like these "super spleen divers" actually have relatively small spleens...

geon 9y ago
Is their body mass significantly lower than the overall human population?
- nonbel 9y ago
  If so, then the relevant measure should have been spleen volume to body mass ratio...
defen 9y ago
The patients in the Yetter paper were all being evaluated for liver disease, so their measurements might not be what you want to use as normal.
- nonbel 9y ago
  Thanks, looking closer at the Yetter paper: >"Normal cadaveric splenic volumes reported by Loftus et al. [8] are 26–250 cm3 with a mean volume of 110 cm3 and an SD of 70 cm3. Henderson et al. [19] reported a normal splenic volume of 219 cm3 as calculated from axial CT acquisitions." So an average of 219 cm^3 according to axial CT is still larger than what is seen here. I'm not sure about the cadaver spleens, do they shrink? The Loftus paper only reports maximum length vs actual volume so we can't see that direct correlation. Some other papers report 184 cm^3 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4549594/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4549594/) and 214.6 cm^3 (https://www.ncbi.nlm.nih.gov/pubmed/9038125 https://www.ncbi.nlm.nih.gov/pubmed/9038125)

darkerside 9y ago

Yeah, lines like this are ridiculous. “I would think, as morbid as it is, that if they didn’t have this, it would kill them,” she said. Yeah, and by a similar leap of logic, if we didn't have two legs, we'd flop around on the land like fish.