Faculty Bibliography

To better understand the contribution of interferon-gamma (IFN-gamma) to the immune response during the first 60 days of mycobacterial infection in the lungs, IFN-gamma gene disrupted (IFN-gamma-/-) mice were infected via aerosol with recombinant Mycobacterium bovis Bacillus Calmette-Guerin (BCG) secreting murine IFN-gamma (BCG-IFN-gamma) and compared to mice infected with recombinant BCG containing the vector only (BCG-vector). When IFN-gamma-/- mice were infected with BCG-vector, increasing bacillary loads and large undifferentiated granulomas that did not express inducible nitric oxide synthase (iNOS) were observed in the lungs. In contrast, infection with BCG-IFN-gamma resulted in reduced bacillary load and better differentiated granulomas containing epithelioid macrophages expressing iNOS as well as reduced levels of interleukin 10 (IL-10) mRNA. However, local production of IFN-gamma by the recombinant BCG did not protect IFN-gamma-/- mice from subsequent challenge with M. tuberculosis. Infection of IFN-gamma-/- peritoneal macrophages in vitro with BCG-IFN-gamma led to induction of iNOS expression and lower IL-10 mRNA levels. Nevertheless, the growth of the intracellular BCG was unaffected. Since IFN-gamma induced-iNOS protein and reduced IL-10 production were insufficient to control mycobacterial growth in vitro, the results suggest that additional mediator(s) present in vivo are required for control of mycobacterial growth

BACKGROUND: The differentiation between malignant mesothelioma and adenocarcinoma based on morphology alone can be a diagnostic challenge. The majority of the available antibodies recognize molecules expressed by adenocarcinoma whereas to the authors' knowledge specific markers for mesothelial cells are lacking. Calretinin, a calcium-binding protein, has been reported to be a selective marker for mesothelioma and largely is absent from adenocarcinoma on histologic material. The results with cytologic preparations have been inconsistent. METHODS: To evaluate the specificity of calretinin in differentiating mesothelioma from adenocarcinoma in cytologic preparations, 21 paraffin embedded cells blocks of serous effusions from 15 patients with metastatic adenocarcinoma and 16 cell blocks from 9 patients with malignant mesothelioma were stained with a monoclonal antibody against calretinin. The immunoreactivity was evaluated blindly by two observers. Positive staining was defined as nuclear and cytoplasmic staining with or without intense membranous decoration. The former resulted in a characteristic 'fried egg' appearance. RESULTS: Calretinin staining was positive in all but 2 cases of mesothelioma (14 of 16 cases; 87.5%). The latter contained predominantly spindle-shaped neoplastic mesothelial cells in the cell block preparations. All adenocarcinoma specimens were classified as negative for calretinin staining; 9 (42.9%) lacked any immunoreactivity and 12 (57.1%) showed weak, sparse, coarse, granular cytoplasmic staining without nuclear or membranous staining. Benign reactive mesothelial cells, when observed in association with adenocarcinoma, also showed the characteristic 'fried egg' appearance. The difference in the staining pattern of calretinin between cells of mesothelial origin and adenocarcinoma cells was statistically significant. CONCLUSIONS: Calretinin is a useful marker in differentiating mesothelioma of the epithelial type from adenocarcinoma in serous effusions. The 'fried-egg' appearance or cytoplasmic and nuclear staining pattern is characteristic of cells of mesothelial origin

In our efforts to understand the infrared spectral features of cells and tissues, and the spectral changes occurring between normal and disease states, we reported previously a detailed correlation between histochemical/immunohistochemical and spectral results. These results suggested an increase of nucleic acid spectral contributions in neoplastic, as compared to normal, tissue samples. In the present paper, these studies are extended to report the spectral features of DNA and RNA separately in these tissue samples. This was accomplished by selectively digesting either DNA or RNA from tissue sections, leaving behind the protein matrix with nuclear/cytoplasmic RNA or the protein matrix with nuclear DNA, respectively. These results demonstrate that the spectral changes between normal and neoplastic tissue are mostly due to an enhanced signature of DNA in neoplastic tissue. This enhancement is sufficiently Large to suggest that it is most likely due to an increased detectability of DNA, rather than an increase in concentration

Infrared spectra of selected regions of normal, cirrhotic, and neoplastic liver tissue samples are reported. Spectra of these tissues may vary for a number of reasons that may or may not be related to the state of health or disease, With the use of histochemical and immunohistochemical methods, the spectral variations are interpreted in terms of the biochemical and pathological processes involved. This paper lays the groundwork for correlation of infrared spectroscopic and pathological/histochemical results for other tissues, to be reported in subsequent communications

Experimental and computational methods of infrared microspectroscopy (IRI-MSP) and infrared spectral mapping (ISM) are presented. These methods are subsequently applied to the analysis of cirrhotic liver tissue. The sensitivity of infrared spectral mapping toward spectral changes caused by disease will be demonstrated. In addition, the excellent agreement between ISM data and histopathological information will be discussed.

Infrared microspectral maps of healthy and diseased liver tissue are reported, along with the methodology for obtaining such maps and methods for their interpretation. The results suggest that present technology permits maps to be collected that contain useful pathological information.

The diagnosis of prostate cancer is based on the visible microscopic evaluation of both cytological and architectural features of the prostate tissue sections. In order to determine whether infrared (IR) spectral "mapping" can be used to objectively distinguish between normal and neoplastic prostate tissue, a comparison between " visual, point-by-point" and "automated, point-by-point" infrared measurements was performed. Automated, point-by-point analysis was performed without any prior diagnostic information. Visual, point-by-point measurements were based on histopathology, histochemistry and immunohistochemical analysis of the tissue samples. The spectra obtained from these measurements were compared to the spectra obtained from automated point-by-point analysis. Our results indicate that the spectra obtained from histopathologically directed measurements compares well with those of automated mapping methods. Therefore, we believe that current mapping methodology can be directly correlated with pathological diagnoses.

Small, extraportal, hepatic parenchymal cells, positive for biliary-type cytokeratins, may represent hepatic stem cells, canals of Hering (CoH), and/or ductal plate remnants. We evaluated these cells 3 dimensionally in normal human liver and massive necrosis. Tissues from normal human livers and from 1 liver with acetaminophen-induced massive necrosis were serially sectioned, immunostained for cytokeratin 19 (CK19), and sequentially photographed. Images were examined to determine 3-dimensional relationships among CK19-positive cells. Immunostains for other hepatocyte and progenitor cell markers were examined. In normal livers, intraparenchymal CK19-positive cells lined up as linear arrays in sequential levels. One hundred of 106 (94.3%) defined, complete arrays within levels examined, most having 1 terminus at a bile duct, the other in the lobule, beyond the limiting plate. In massive necrosis, there were 767 individual CK19-positive cells or clusters around a single portal tract, 747 (97.4%) of which were spatially related forming arborizing networks connected to the interlobular bile duct by single tributaries. C-kit was positive in normal CoH. CK19 co-expressed with HepPar1, c-kit, and alpha-fetoprotein (AFP) in parenchymal cells in massive necrosis. Small, extraportal, biliary-type parenchymal cells represent cross-sections of the CoH that radiate from the portal tract, usually extending past the limiting plate into the proximate third of the hepatic lobule. The 3-dimensional structure of ductular reactions in massive necrosis suggests that these reactions are proliferations of the cells lining the CoH. Therefore, the CoH consist of, or harbor, facultative hepatic stem cells in humans