Historically, sickle-cell anemia has been an unheralded killer. It does
not occur in dramatic epidemics. Its victims in the U.S. are mostly
blacks, and they generally receive less medical attention than whites.
The malady affects the red blood cells, which normally are spherical.
When the anemia victim is under any stress that reduces the oxygen
supply in his blood, his red cells elongate into firm gel-like
crescents that block narrow capillaries and deprive tissues
of vital oxygen. The cause of the disease is a gene mutation that occurred centuries ago
in Africa. The estimated 2,000,000 Americans who carry one defective
gene usually show no symptoms of the disease. The one child in 500 who
inherits a sickle-cell gene from each parent has barely an even chance
of seeing his 20th birthday and, if he does survive into middle age, is
likely to be crippled. Sickle-cell anemia cannot be cured, though treatment can sometimes
control its effects. It can be almost completely prevented, provided
that partners who both carry the trait avoid having children. The
missing element has been a simple test that would allow carriers to be
identified and warned. Now this crucial procedure has been perfected. Freezing Blood. At a recent meeting of the American Association of Blood
Banks in Chicago, Dr. Paul Wolf of Stanford University and Dr. Robert
Nalbandian of Blodgett Memorial Hospital in Grand Rapids, announced
their success after three years of experiments. They emphasized that
they had built on the pioneering studies of Makio Murayama of the
National Institutes of Health. Murayama observed that abnormal cells,
which carry sickle-producing hemoglobin S, gel at normal body
temperature when oxygen content is reduced, then return to normal at
32 F. Working in cooperation with other researchers, Wolf and Nalbandian
discovered chemicals that would react to hemoglobin S and other less
harmful sickling substances, making a quick screening test possible. A
small blood sample is dropped into a tube containing a solution of
potassium phosphate, sodium dithionite and saponin. Clouding of the
solution is a danger signal but does not specifically identify
hemoglobin S. If the first round arouses suspicion, a second test, also
based on Murayama's work, is performed immediately. Urea, a natural
waste substance produced by the normal liver, breaks some molecular
bonds in abnormal hemoglobin. When urea is added to the solution that
had shown a positive reaction initially, the liquid clears quickly if
hemoglobin S is present. Neglected Ailment. The Wolf-Nalbandian tests do not distinguish between
those who merely carry the sickle-cell trait and those actually
affected by the disease. But they do provide a fast, inexpensive method
of finding individuals who should get further attention. In an
experimental program at Fort Knox, Ky., doctors tested 7,000 black
soldiers, 94 of whom were found to carry hemoglobin S. Two of these
soldiers actually had sickle-cell anemia.
