Coming to Terms with Death

By Raloff, Janet | Science News, June 16, 2001 | Go to article overview

Coming to Terms with Death

Raloff, Janet, Science News

Accurate descriptions of a cell's demise may offer clues to diseases and treatments

Death is a part of living--and an essential one. From conception onward, cells divide over and over again. Their endless proliferation would quickly lead to elephantine bodies were it not for a compensating death of cells.

But cells' deaths can achieve far more than just crowd control. During fetal development, a symphony of cell deaths sculpts the body. During sickness, cascades of biochemical events euthanize diseased cells. Even healthy cells, as they age and lose vigor, commit suicide for the good of the organism.

The typical adult may create 10 billion new cells every day--and kill off an equal number. Indeed, cancers stem from cells that have foresworn the natural suicide plan that's programmed into an organism's genes. The progeny of these renegade masses of prolific immortals eventually set up squatter colonies that crowd out healthy tissues and siphon off resources.

Until recently, most biologists classified cell deaths into two categories. In apoptosis, genetically programmed suicide shapes an organism or rids it of diseased cells. Necrosis, in contrast, includes cell deaths resulting from some outside force.

During the past few years, however, several biologists and pathologists have begun to challenge this bimodal classification, arguing that it's both overly simplistic and misleading. For instance, some researchers have found a type of programmed cell death that bears little resemblance to apoptosis. Others report a novel form of cell homicide that targets malignant cells.

Recently, a panel of scientists reconsidered the classification of cell death and argued for more precise descriptions.

At stake is more than nomenclature, however. By misdiagnosing how cells die, some scientists argue, the medical community risks overlooking new ways to halt untimely deaths--or to foster them for the sake of cancer therapy.

Two years ago, a California scientist stumbled onto evidence for one of these new types of cell death while she was attempting to measure rates of apoptosis in genetically modified human cancer cells.

Sabina Sperandio of the Buck Institute for Age Research in Novato, Calif., inserted into lab-cultured cell lines various genes that would make the cells dependent on a particular hormone or protein. She expected that in the absence of this chemical partner, the cells would undergo apoptosis.

In one experiment, Sperandio made a line of human cells dependent on insulin-like growth factor 1. As predicted, when she incubated these cells without the factor, they began dying. However, they didn't exhibit predictable features of apoptosis.

Concerned that she was doing something wrong, Sperandio consulted her boss, Dale E. Bredesen. He says that after one glance, he saw that Sperandio had triggered in the cells a process that "didn't look anything like apoptosis."

Typically in apoptosis, the membrane of a dying cell softens and blebs balloon out. Meanwhile, the cell's nucleus shrinks and then divides. Eventually, the cells break into large fragments, which the body's roving cleanup crews discard. Enzymes, called caspases, trigger this apoptosis.

However, the cells that Sperandio created were doing something different. There was no membrane blebbing, no fragmentation of the nucleus, and no cell breakup. Moreover, chemicals that inhibit apoptosis didn't prevent the cells' suicide.

Instead, the cells were swelling and developing large bubbles, or vacuoles, with liquid inside them. These cells, Bredesen recalls, resembled a condition that other biologists had periodically described as "type 3 cell death" since at least the early 1970s.

In the Dec. 19, 2000 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES, Sperandio, Bredesen, and their colleagues declared this a novel kind of cell suicide, dubbing it paraptosis. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Cite this article

Cited article

Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25,

Note: primary sources have slightly different requirements for citation. Please see these guidelines for more information.

Cited article

Coming to Terms with Death


Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Full screen

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25,

    New feature

    It is estimated that 1 in 10 people have dyslexia, and in an effort to make Questia easier to use for those people, we have added a new choice of font to the Reader. That font is called OpenDyslexic, and has been designed to help with some of the symptoms of dyslexia. For more information on this font, please visit

    To use OpenDyslexic, choose it from the Typeface list in Font settings.

    OK, got it!

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Author Advanced search


    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.