Nontransgenic models of breast cancer

Numerous models have been developed to address key elements in the biology of breast cancer development and progression. No model is ideal, but the most useful are those that reflect the natural history and histopathology of human disease, and allow for basic investigations into underlying cellular and molecular mechanisms. We describe two types of models: those that are directed toward early events in breast cancer development (hyperplastic alveolar nodules [HAN] murine model, MCF10AT human xenograft model); and those that seek to reflect the spectrum of metastatic disease (murine sister cell lines 67, 168, 4T07, 4T1). Collectively, these models provide cell lines that represent all of the sequential stages of progression in breast disease, which can be modified to test the effect of genetic changes.     

Acute naphthalene toxicity presenting with metabolic acidosis: a rare complication

Naphthalene moth ball poisoning in children can present with diagnostic and therapeutic challenges. A 2 year old boy who had accidentally consumed unknown number of moth balls presented 3 d later with vomiting, seizures, methemoglobinemia, hemolytic anemia and altered sensorium. He was managed with red blood cell transfusion, IV Methylene blue and Sodium bicarbonate. Clinical and laboratory parameters normalized. We describe this case as ingestional naphthalene poisoning with rare manifestation of metabolic acidosis, with a good outcome after treatment.     

Differentiation state and responses to hematopoietic growth factors of murine myeloid cells transformed by myb

Murine hematopoietic cells can be transformed in vitro by recombinant retroviruses that express the myb oncogene, and hematopoietic growth factor (HGF)-dependent myeloid cell lines can be derived from these transformed primary cells. In this study, the differentiation state and responses of myb-transformed hematopoietic cells (MTHCs) have been investigated. We find that MTHCs exhibit properties of early myeloid progenitors including synergistic responses to combinations of HGFs and expression of certain surface markers. As reported previously, MTHCs respond well to granulocyte-macrophage colony-stimulating factor (GM- CSF) but can also respond to interleukin-3 (IL-3); the response to the latter factor depends on the mouse strain from which the cells are derived. Although these single factors stimulate MTHCs, combinations of these factors with colony-stimulating factor-1 (CSF-1 or M-CSF) or Steel factor (SLF or SCF) act synergistically to promote colony formation. The surface markers expressed by MTHCs include both granulocyte-macrophage lineage specific antigens Gr-1, 7/4, F4/80, and Mac-1, as well as two antigens found on early progenitors and stem cells--Thy-1 and Sca-1 (Ly6E). Expression of the latter markers is often heterogeneous and can be modulated by the growth factors to which the cells are exposed. Finally, we show that monocytic differentiation of MTHCs can be induced by exposure to tumor necrosis factor (TNF alpha). Taken together, these results suggest that MTHCs will be a useful model for studying HGF/cytokine responses in both proliferation and differentiation.     

A longitudinal molecular surveillance study of human polyomavirus viremia in heart, kidney, liver, and pancreas transplant patients

In this study of 263 heart, kidney, liver, and pancreas transplant patients, BK virus (BKV) and JC virus (JCV) DNAemia were observed most commonly in kidney and/or pancreas transplant patients (26%), although they were also observed, to a lesser extent, in heart (7%) and liver (4%) transplant patients. The majority of episodes of polyomavirus DNAemia were subclinical, although, in some cases, BKV DNAemia was associated with kidney rejection, and JCV DNAemia was accompanied by nonspecific symptoms. Hence, BKV and JCV DNAemia are not uncommon during the first year after kidney, heart, liver, and pancreas transplantation, and they could be associated with certain clinical syndromes in transplant patients.