Articles 
Ben-David, Y., and Bernstein, A. 1991. Friend 
virus-induced erytlaroleukemia and the multi- 
stage nature of cancer. Cell 66:831-834. 
Forrester, L.M., Bernstein, A., Rossant, J., and 
Nagy, A. 1991. Long-term reconstitution of the 
mouse hematopoietic system by embryonic stem 
cell-derived fetal liver. Proc Natl Acad Sci USA 
88:7514-7517. 
Forrester, L.M., Brunkow, M., and Bernstein, A. 
1992. Proto-oncogenes in mammalian develop- 
ment. Curr Opin Genet Dev 2:38-44. 
Joshi, S., Van Brunschot, A., Asad, S., van der Fist, I., 
Read, S.F., and Bernstein, A. 1991. Inhibition of 
human immunodeficiency virus type 1 multipli- 
cation by antisense and sense RNA expression. / 
Wro/ 65:5524-5530. 
Lavigueur, A., and Bernstein, A. 1991. p53 trans- 
genic mice: accelerated erythroleukemia induc- 
tion by Friend virus. Oncogene 6:2197-2201. 
McGlade, C.J., Ellis, C, Reedijk, M., Anderson, D., 
Mbamalu, G., Keith, A.D., Panayotou, G., End, P., 
Bernstein, A., Kazlauskas, A., Waterfield, M.D., 
and Pawson, T. 1992. SH2 domains of the p85a 
subunit of phosphatidylinositol 3'-kinase regulate 
binding to growth factor receptors. Mol Cell Biol 
12:991-997. 
Meininger, C.J., Yano, H., Rottapel, R., Bernstein, 
A., Zsebo, K.M., and Zetter, B.R. 1992. The c-kit 
receptor ligand functions as a mast cell chemoat- 
tractant. 79:958-963. 
Miller, B.A., Perrine, S.P., Bernstein, A., Lyman, 
S.D., Williams, D.E., Bell, L.L., and Olivieri, N.F. 
1992. Influence of steel factor on hemoglobin 
synthesis in sickle cell disease. Blood 79:1861- 
1868. 
Motro, B., van der Kooy, D., Rossant, J., Reith, A., 
and Bernstein, A. 1991. Contiguous patterns of 
c-kit and steel expression: analysis of mutations at 
the ITand SI loci. Development 113:1 207- 1221. 
Olivieri, N.F., Grunberger, T., Ben-David, Y., Ng, J., 
Williams, D.E., Lyman, S., Anderson, D.M., Ax- 
elrad, A.A., Correa, P., Bernstein, A., and Freed- 
man, M.H. 1991. Diamond-BIackfan anemia: het- 
erogenous response of hematopoietic progenitor 
cells in vitro to the protein product of the steel 
locus. 6/00^/78:2211-2215. 
Reith, A.D., and Bernstein, A. 1991. Molecular 
basis of mouse developmental mutants. Genes 
Dev 5:1115-1123. 
Reith, A.D., ElHs, C., Lyman, S.D., Anderson, D.M., 
Williams, D.E., Bernstein, A., and Pawson, T. 
1991. Signal transduction by normal isoforms and 
W mutant variants of the Kit receptor tyrosine ki- 
nase. EMBO J 10:2451-2459. 
MOLECULAR BIOLOGY OF TWO ENTEROPATHOGENIC BACTERIA 
Edmundo Calva, Ph.D., International Research Scholar 
Typhoid fever (TF) in humans is the clinical man- 
ifestation of a systemic infection by Salmonella ty- 
phi, a gram-negative enterobacterium, which is 
usually ingested via contaminated food or water. TF 
is estimated to affect annually more than 12 million 
persons worldwide, and the case fatality rate is 1%. 
The process of infection entails a series of bacteria- 
host interactions that are amenable to the basic 
study of a variety of biological phenomena. The 
mechanisms by which Salmonella reaches the in- 
testinal tract, adheres to intestinal cells, resists 
phagocytosis, and multiplies within macrophages 
are largely unknown, although rapid progress has 
been achieved in the past few years regarding the 
molecular mechanisms involved in the invasion of 
epithelial cells by bacterial pathogens. Research in 
TF thus offers the opportunity to explore many 
aspects of bacterial molecular genetics, pathogene- 
sis, and host immune response. The information ob- 
tained could provide relevant insights for the design 
of improved diagnostic tests and vaccines for TF, as 
well as on the biological processes involved in other 
bacterial infections. 
Diarrheal diseases are considered the second 
leading cause of global deaths from illness, with an 
estimated number of 5 million during 1991. The 
fatalities are second only to those from cardiovascu- 
lar disease and exceed those from cancer, pneumo- 
nia, tuberculosis, or AIDS. Campylobacter jejuni, a 
gram-negative, vibroid bacterium, is one of the ma- 
jor causal agents of diarrhea worldwide. Knowledge 
is scarce on the genome structure and function of 
this organism and, in the same context as described 
above for S. typhi, on its pathogenic mechanisms. 
Therefore studies in this field also offer opportuni- 
ties for the probing of interesting biological phe- 
nomena, with the added benefit of providing knowl- 
edge potentially useful for health interventions. 
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