Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: THURSDAY, August 3, 1995                   TAG: 9508030008
SECTION: EXTRA                    PAGE: 3   EDITION: METRO 
SOURCE: JOEL ACHENBACH
DATELINE:                                 LENGTH: Long

WOULD WE MAKE UP THESE QUESTIONS?

First, Bev S., of El Cerrito, Calif., asks, ``How do sperm and eggs stay alive when frozen?''

Dear Bev: Through extremely vigorous fantasizing, maybe?

Our source, Preston Sacks, endocrinologist at Columbia Hospital for Women in Washington, D.C., says that fertility specialists don't just put the sperm and eggs in the freezer next to the Ben & Jerry's and hope for the best. Rather, the first thing they do is dehydrate the stuff.

You have to get rid of the water because when it freezes it forms crystals and expands (water is an unusual substance in that it gets larger, not smaller, when it becomes a solid). The expanding water could rip up the sperm or egg.

So the sperm or egg is bathed in a solution of the replacement liquid until the water washes out. A typical replacement is DMSO, dimethyl sulfoxide, the well-known pain reliever. Then the sperm or eggs are frozen to about 270 degrees below zero Fahrenheit, where they have no metabolic processes whatsoever.

Why don't they die at some point? Most do. But they are simple things, one-celled, and some survive. It is the larger organisms, with different kinds of cells and different freezing and thawing rates, that can't be put into suspended animation in the deep freeze, according to Sacks.

That said, eggs are not ideal for cryopreservation. They're too fragile. Their DNA is particularly vulnerable to damage. Moreover, there aren't many eggs. They're large, few and precious. Sperm by contrast are as numerous and expendable as peel-and-smell perfume strips in a copy of Vanity Fair. There are tens if not hundreds of millions of the little gators in every donation to the sperm bank.

So if the survival rate in the freezing process is only, say, 20 percent, that still means millions of surviving sperm, all ready and eager to belly up to the bar.

There are other reasons why it is easier to freeze a sperm than an egg but we are bored with the issue and want to answer this question from Dave G., of Rochester, N.Y.: ``Why is the blade on a guillotine at an angle?''

Dear Dave: You can easily visualize why an angled blade does the job better, though we recommend that you think of a cigar cutter, since we don't want any of our readers fainting at the mention of heads rolling into baskets and so forth.

A good cigar needs a clean cut. If you just try to chop off the end, you could get splaying, mashing and ripping of the tobacco leaves. So the guillotine-style cigar cutter has an angled blade that comes in on one side, making a tiny initial incision, gradually slicing through the meat of the stogie.

For the same reason you don't use a meat cleaver to chop off a ``slice'' of bread.

Now then, someone asked us, ``Why do dead bodies seem to weigh more than live ones?''

Dear someone: We can only tell you what we know about the difference between sleeping kids and conscious kids. Sleeping kids weigh more. This is because a sleeping child is precisely like a sack o' taters, a seemingly boneless mass of tissue; as the child dreams it has no muscle tone at all. The little angel is just flopped and drooped all over the place.

As for corpses, we called Michael Graham, chief medical examiner for the City of St. Louis, and he said that a conscious person can help you in subtle ways as you carry him or her along, specifically by holding the body stiffly in key places. A corpse, he said, is of no help in such a situation. Obviously there is no weight change between a living and deceased person.

Graham said that corpses don't strike him as feeling heavier than live people, but he noted, ``The only people I ever pick up are dead people.''

Next: We are constantly being asked, ``Why don't you ever see baby pigeons?''

Dear who-wants-to-know: Because a pigeon at two months looks almost exactly like an adult pigeon. It has the same coloration. They grow up fast.

``They look mature but they're actually very young,'' says Marie Rotondo, secretary-treasurer of the International Federation of American Homing Pigeon Fanciers.

If a bird is recently fledged it will have a few tufts of down mixed with the feathers. But you have to look closely. The first month or so the pigeons stay in the nest, which is likely to be out of the way, perhaps under a bridge or in a gutter. So one reason you don't see baby pigeons is that you stay away from the kind of places they like.

And finally, Cody W., who is in Mrs. Wilkinson's first grade class in Huntertown, Ind., writes, ``Mrs. Wilkinson gave us each a butterfly caterpillar. We have watched it grow and become a chrysalis. Mrs. Wilkinson read your article to us. We think you would like to know that butterflies make a chrysalis and moths do not. Maybe you did not get a chance to learn this in first grade.''

Dear Cody: Right you are, lad. We got moths and butterflies lumped up in some versions of the column. Moth caterpillars metamorphose in a cocoon, butterfly caterpillars in a chrysalis. And for the record, we did attend first grade, we just didn't graduate.

- Washington Post Writers Group