Plant cells contain specialized structures, such as a cell wall and a large vacuole, which play a major role in cell growth. Roots follow an organized pattern of development, making them the organs of choice for studying the spatio-temporal regulation of cell proliferation and growth in plants. During root growth, cells originate from the initials surrounding the quiescent center, proliferate i...

Neocortical neuronogenesis occurs in the pseudostratified ventricular epithelium (PVE) where nuclei of proliferative cells undergo interkinetic nuclear movement. A fraction of daughter cells exits the cell cycle as neurons (the quiescent, or Q, fraction), whereas a complementary fraction remains in the cell cycle (the proliferative, or P, fraction). By means of sequential thymidine and bromodeo...

AIDS-related non-Hodgkin's lymphoma (AIDS NHL) comprises a diverse and heterogeneous group of high-grade B cell tumors. Certain classes of AIDS NHL are associated with alterations in oncogenes or tumor-suppressor genes or infections by oncogenic herpesviruses. However, the clinically significant class of AIDS NHL designated immunoblastic lymphoma plasmacytoid (AIDS IBLP) lacks any consistent ge...

Between 2.5 and 4 days of development, cell proliferation in the Xenopus eye becomes confined to a narrow ring of germinal cells at the front rim of the eye cup. Continued growth of the eye (which lasts until well beyond metamorphosis) is by the continued proliferation of cells in this germinal zone. To determine what factor(s) promotes cell division in this region of the eye long after it ceas...

Four large earthquakes occurred in 1980 in a seismic gap near the Loyalty Islands in the New Hebrides. At 3:25 UT on October 24 an event with M, = 6.7 initiated the sequence. Three events, M, = 6.7, 7.2, and 6.5, followed on the next day. We investigated this sequence by using the seismicity, first-motion, and wavefonn data and long-period surface waves. The first-motion data constrain one of e...