Immunophenotyping of human HT29 colon cancer cell primary tumours and their metastases in severe combined immunodeficient mice

The immunophenotype of HT29 human colon cancer cells implanted into severe combined immunodeficient mice was assessed in primary tumours and their metastases in the lungs using an indirect immunohistochemical method. After primary tumours were surgically removed, the metastases were given time to develop, thus paralleling the clinical situation. While vimentin was negative in both primary and secondary tumours, E-cadherin was present as membrane-bound labelling in the primary tumours only. Whereas the markers p53, MIB1, PCNA and CEA were consistently positive in both primary and metastatic tumours, CD44 variant 6 and CA125 were negative in metastases but positive in the primary tumours. There was a significant increase in the percentage of cells labelled for p53 in the primary tumours compared with the metastases. For the proliferation markers, there was no significant difference in labelling between primary tumours and metastases for MIB1. Of the cytokeratins examined, CK 20 gave the strongest and most consistent reaction in both primary and secondary tumours. The results indicate that, for certain immunohistochemical markers, results are the same in both primary tumours and metastases. Hence, in these cases, antigens that are expressed on the primary tumour as well as on the metastases can serve as target molecules for immunologically based forms of treatment of metastases. This revised version was published online in November 2006 with corrections to the Cover Date.     

The epidemiologic transition in a frontier town — Manti,Utah: 1849–1977

Census reports and information in burial records of Manti, Utah from 1849 to July 1977 are examined in order to (1)document mortality trends and differentials by age, sex, cause-of-death, and seasonality as Manti passed from a frontier settlement to a rural agricultural community; and (2) ascertain whether the shifts in the cause-of-death structure follow those patterns outlined by Omran (1971, 1974, 1977) in his theory of the epidemiologic transition. Findings parallel patterns suggested by Omran. Major factors accounting for mortality reductions are (1) elimination of the population's dependence upon a contaminated water supply, and (2) adoption of medical advances as they became available.     

The assessment of cellular proliferation by immunohistochemistry: A review of currently available methods and their applications

Summary Immunohistochemical methods using antibodies to cell cycle-related antigens may be used as a means of assessing various aspects of proliferation in tissue, and have the important advantage of preserving the spatial orientation of proliferating cells in histological sections. Currently, the most widely available antibodies for this purpose are antibodies to bromodeoxyuridine (BrdU), Ki67 and antibodies to proliferating cell nuclear antigen (PCNA). BrdU is a thymidine analogue incorporated during the S phase of the cell cycle, which can be introduced by in vivo administration or by in vitro incubation, and monoclonal antibodies are available to display its localization. Ki67 demonstrates a nuclear antigen expressed in all phases of the cell cycle, except G₀ and early G₁, but can only be applied to frozen tissue. PCNA is a nuclear antigen which is essential for DNA synthesis, two commercially available antibodies to PCNA work in paraffin-embedded tissue, but may have different staining characteristics under different conditions of fixation. The main advantages and disadvantages of these different techniques are discussed, together with their main applications to date.     

Death effector activation in the subventricular zone subsequent to perinatal hypoxia/ischemia

Perinatal hypoxia/ischemia (H/I) is the leading cause of neurological injury resulting from birth complications and pre-maturity. Our studies have demonstrated that this injury depletes the subventricular zone (SVZ) of progenitors. In this study, we sought to reveal which cell death pathways are activated within these progenitors after H/I. We found that calpain activity is detected as early as 4 h of reperfusion and is sustained for 48 h, while caspase 3 activation does not occur until 8 h and peaks at 24 h post-insult. Activated calpains and caspase 3 co-localized within precursors situated in the lateral aspects of the SVZ (which coincides with progenitor cell death), whereas neither enzyme was activated in the medial SVZ (which harbors the neural stem cells that are resilient to this insult). These studies reveal targets for neuroprotective agents to protect precursors from cell death towards the goal of restoring normal brain development after H/I.     

A simplified dehydrogenase enzyme assay in contaminated sediment using 2-(p-Iodophenyl)-3(p-nitrophenyl)-5-phenyl tetrazolium chloride

2-(p-Iodophenyl)-3(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT) accepts electrons from dehydrogenase enzymes and is reduced to a red-colored formazan (INTF), which can be quantified by colorimetric analysis. Use of previously published methods for this technique was unsuccessful due to background chemical reactions from high levels of polycyclic aromatic hydrocarbons (PAHs) and metals in the sediments. A modified method using acetonitrile extraction of the INTF was efficient and did not chemically reduce INT. This activity method is simple, quick, inexpensive and precise.