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THE LAST WORD Achoo blues Twice, when donating blood platelets to the Red Cross, I’ve started sneezing uncontrollably. Assistants respond immediately by giving me Tums, a brand of antacid indigestion tablet. Their explanation is that Tums restores my calcium balance. I understand how my calcium could get out of whack when my blood is being removed, filtered and given back to me without platelets, but what does this have to do with sneezing?
■ Donating platelets involves the use of a plateletpheresis machine, which draws and separates platelets from a donor’s blood before returning red cells and plasma to the donor’s bloodstream. A solution called acid citrate dextrose is added to the blood to stop clotting during this process: citrate, in particular, has the effect of lowering blood calcium levels to a point where the blood cannot clot in the machine. This calcium deficiency, or hypocalcaemia, may cause side effects when blood from the
“Citrate has the effect of lowering blood calcium levels to the point where the blood cannot clot” machine is returned to the donor’s body. Symptoms include tingling, chills, slight nausea, bruising, fatigue and dizziness; the most frequent one is tingling around the lips.
Questions and answers should be concise. We reserve the right to edit items for clarity and style. Include a daytime telephone number and email address if you have one. Restrict questions to scientific enquiries about everyday phenomena. The writers of published answers will receive a cheque for £25 (or US$ equivalent). Reed Business Information Ltd reserves all rights to reuse question and answer material submitted by readers in any medium or format.
Sneezing is not a common side report terms it. These have been effect, but low calcium levels estimated as between 0.8 times could cause tingling in the nasal (in New Zealand) and three passages and hence sneezing. times (in Switzerland) as high The treatment for this is first as the accident-related death to slow down the rate of platelet rate, so perhaps it would be collection and then to supply correct to double the estimate the donor with antacid tablets, “The current annual a rich source of supplementary death rate due to motor calcium. If this is not effective, vehicles is at least double the procedure may have to be those caused by war” halted until symptoms resolve and a decision made over whether of deaths due to motor vehicles to proceed at a lower rate of to 2.4 million. platelet collection. We should also factor in an Richard Benjamin estimate for deaths due to climate Chief medical officer change caused by vehicle and American Red Cross petroleum industry carbon Washington DC, US dioxide emissions. A definite value for this number of deaths Wheels of death will presumably remain unknown I heard the car is the deadliest until it starts to reach tens of weapon created by humans and that millions per year, because it is the number of lives it has claimed difficult to attribute individual exceeds the death toll from atomic droughts, storms or floods to weapons, guns or bombing. Is climate change. this true? And what are the grisly Even disregarding climatefigures involved? change deaths, however, the (Continued) current annual rate of deaths due to motor vehicles is at least double ■ By not considering the less that caused by war. developed countries, some of Philip Ward your previous correspondents By email, no address supplied have neglected nearly 90 per cent of deaths caused by road THIS WEEK’S traffic accidents. The World QUESTIONS Health Organization estimates SPEED FREAKS the total is 1.2 million deaths A single Formula 1 car passing per year, the majority of these by makes a noise of around 110 probably being pedestrians decibels. Last year I went to a and cyclists. Formula 1 Grand Prix and sat near It is also necessary to add the start line, where 20 cars left the deaths from “traffic-related the grid at once. The noise was air pollution”, as another WHO
New Scientist retains total editorial control over the content of The Last Word. Send questions and answers to The Last Word, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, UK, by email to [email protected] or visit www.last-word.com (please include a postal address in order to receive payment for answers). For a list of all unanswered questions send an SAE to LWQlist at the above address.
Do Polar Bears Get Lonely? A brand new collection ight serious enquiry, brilliant insight cted and the hilariously unexpected Available from booksellers m/ and at www.newscientist.com/ polarbears
mind-numbing, much louder than a single car, but not 20 times louder (or 2200 decibels, an unachievable figure). Why wasn’t it? Walter Coppin Edinburgh, UK STICKY PROBLEM
What caused this tree resin, emerging where a branch was sawn off, to flow out at an angle, then vertically downwards, before flowing in an upward curve (see photo)? Rupert Ward Albany, Western Australia
THE RIGHT PATH
A pathway in my neighbourhood splits at an incline into both steps and a slope. Which option requires more calories to walk up or down? Yonatan Silver Jerusalem, Israel
THE LAST WORD Achoo blues Twice, when donating blood platelets to the Red Cross, I’ve started sneezing uncontrollably. Assistants respond immediately by giving me Tums, a brand of antacid indigestion tablet. Their explanation is that Tums restores my calcium balance. I understand how my calcium could get out of whack when my blood is being removed, filtered and given back to me without platelets, but what does this have to do with sneezing?
■ Donating platelets involves the use of a plateletpheresis machine, which draws and separates platelets from a donor’s blood before returning red cells and plasma to the donor’s bloodstream. A solution called acid citrate dextrose is added to the blood to stop clotting during this process: citrate, in particular, has the effect of lowering blood calcium levels to a point where the blood cannot clot in the machine. This calcium deficiency, or hypocalcaemia, may cause side effects when blood from the
“Citrate has the effect of lowering blood calcium levels to the point where the blood cannot clot” machine is returned to the donor’s body. Symptoms include tingling, chills, slight nausea, bruising, fatigue and dizziness; the most frequent one is tingling around the lips.
Questions and answers should be concise. We reserve the right to edit items for clarity and style. Include a daytime telephone number and email address if you have one. Restrict questions to scientific enquiries about everyday phenomena. The writers of published answers will receive a cheque for £25 (or US$ equivalent). Reed Business Information Ltd reserves all rights to reuse question and answer material submitted by readers in any medium or format.
Sneezing is not a common side report terms it. These have been effect, but low calcium levels estimated as between 0.8 times could cause tingling in the nasal (in New Zealand) and three passages and hence sneezing. times (in Switzerland) as high The treatment for this is first as the accident-related death to slow down the rate of platelet rate, so perhaps it would be collection and then to supply correct to double the estimate the donor with antacid tablets, “The current annual a rich source of supplementary death rate due to motor calcium. If this is not effective, vehicles is at least double the procedure may have to be those caused by war” halted until symptoms resolve and a decision made over whether of deaths due to motor vehicles to proceed at a lower rate of to 2.4 million. platelet collection. We should also factor in an Richard Benjamin estimate for deaths due to climate Chief medical officer change caused by vehicle and American Red Cross petroleum industry carbon Washington DC, US dioxide emissions. A definite value for this number of deaths Wheels of death will presumably remain unknown I heard the car is the deadliest until it starts to reach tens of weapon created by humans and that millions per year, because it is the number of lives it has claimed difficult to attribute individual exceeds the death toll from atomic droughts, storms or floods to weapons, guns or bombing. Is climate change. this true? And what are the grisly Even disregarding climatefigures involved? change deaths, however, the (Continued) current annual rate of deaths due to motor vehicles is at least double ■ By not considering the less that caused by war. developed countries, some of Philip Ward your previous correspondents By email, no address supplied have neglected nearly 90 per cent of deaths caused by road THIS WEEK’S traffic accidents. The World QUESTIONS Health Organization estimates SPEED FREAKS the total is 1.2 million deaths A single Formula 1 car passing per year, the majority of these by makes a noise of around 110 probably being pedestrians decibels. Last year I went to a and cyclists. Formula 1 Grand Prix and sat near It is also necessary to add the start line, where 20 cars left the deaths from “traffic-related the grid at once. The noise was air pollution”, as another WHO
New Scientist retains total editorial control over the content of The Last Word. Send questions and answers to The Last Word, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, UK, by email to [email protected] or visit www.last-word.com (please include a postal address in order to receive payment for answers). For a list of all unanswered questions send an SAE to LWQlist at the above address.
Do Polar Bears Get Lonely? A brand new collection ight serious enquiry, brilliant insight cted and the hilariously unexpected Available from booksellers m/ and at www.newscientist.com/ polarbears
mind-numbing, much louder than a single car, but not 20 times louder (or 2200 decibels, an unachievable figure). Why wasn’t it? Walter Coppin Edinburgh, UK STICKY PROBLEM
What caused this tree resin, emerging where a branch was sawn off, to flow out at an angle, then vertically downwards, before flowing in an upward curve (see photo)? Rupert Ward Albany, Western Australia
THE RIGHT PATH
A pathway in my neighbourhood splits at an incline into both steps and a slope. Which option requires more calories to walk up or down? Yonatan Silver Jerusalem, Israel