Faculty Bibliography

Although an increased frequency of CD4(+)CD8(+) T cells has been observed in the peripheral blood during viral infections, their role, function, and biologic significance are still poorly understood. Here we demonstrate that the circulating CD4(+)CD8(+) T-cell population contains mature effector memory lymphocytes specific for antigens of multiple past, latent, and high-level persistent viral infections. Upon in vitro antigenic challenge, a higher frequency of CD4(+)CD8(+) than single-positive cells displayed a T helper 1/T cytotoxic 1 (Th1/Tc1) cytokine profile and proliferated. Ex vivo, more double-positive than single-positive cells exhibited a differentiated phenotype. Accordingly, their lower T-cell receptor excision circles (TREC) content and shorter telomeres proved they had divided more frequently than single-positive cells. Consistent with expression of the tissue-homing marker CXCR3, CD4(+)CD8(+) T cells were demonstrated in situ at the site of persistent viral infection (ie, in the liver during chronic hepatitis C). Finally, a prospective analysis of hepatitis C virus (HCV) infection in a chimpanzee, the only animal model for HCV infection, showed a close correlation between the frequency of activated CD4(+)CD8(+) T cells and viral kinetics. Collectively, these findings demonstrate that peripheral CD4(+)CD8(+) T cells take part in the adaptive immune response against infectious pathogens and broaden the perception of the T-cell populations involved in antiviral immune responses

AIMS: Hepatocyte proliferation (HP) is an adaptive response to liver injury. The relationships between HP and necroinflammation, fibrosis, and serum alpha-fetoprotein (AFP) levels in chronic hepatitis C virus (HCV) infection, however, are not well understood. METHODS: Proliferative hepatocytes (Ki-67+) were identified using immunohistochemical staining in formalin-fixed, paraffin-embedded liver tissue from 156 HCV RNA-positive patients with different degrees of liver histopathology. Twenty high-power fields (HPFs) in lobular areas were counted in each specimen. RESULTS: HP increased by 1.22 +/- 0.25 cells/HPF per increase in necroinflammation from grade 0 (median: 0.13; range: [0.1-0.5] cells/HPF) through grade 3 (median: 1.80; range: [0.0-25.2] cells/HPF; P=0.002). HP increased by 0.81 +/- 0.20 cells/HPF per increase in fibrosis from stage 0 (median: 0.33; range: [0.0-1.3] cells/HPF) through stage 3 (median: 1.70; range: [0.0-25.2] cells/HPF) and then decreased in stage 4 (to median: 0.90; range: [0.0-5.3] cells/HPF). HP also increased with advancing age (P=0.03). Among patients with advanced liver disease, HP was no higher in patients with elevated serum AFP levels (median: 1.68; range: [0.1-5.3] cells/HPF) than in those with normal serum AFP levels (median: 1.70; range: [0.0-25.2] cells/HPF; P=0.26). CONCLUSIONS: In patients with chronic HCV infection, HP increases with histologic progression of liver disease, but is impaired in cirrhosis. HP was not increased in patients with elevated serum AFP levels

OBJECTIVES: This paper is aimed at establishing infrared spectral patterns for the different tissue types found in, and for different stages of disease of squamous cervical epithelium. Methods for the unsupervised distinction of these tissue types are discussed. METHODS: Fourier transform infrared (FTIR) maps of the squamous and glandular cervical epithelium, and of the cervical transformation zone, were obtained and analyzed by multivariate unsupervised hierarchical cluster methods. The resulting clusters are correlated to the corresponding stained histopathological features in the tissue sections. RESULTS: Multivariate statistical analysis of FTIR spectra collected for tissue sections permit an unsupervised method of distinguishing tissue types, and of differentiating between normal and diseased tissue. By analyzing different spectral windows and comparing the results with histology, we found the amide I and II region (1740-1470 cm(-1)) to be very important in correlating anatomical and histopathological features in tissue to spectral clusters. Since an unsupervised, rather than a diagnostic, algorithm was used in these efforts, no statistical analysis of false-positive/false-negative results is reported at this time. CONCLUSIONS: The combination of FTIR micro-spectroscopy and multivariate spectral processing provides important insights into the fundamental spectral signatures of individual cells and consequently shows potential as a diagnostic tool for cervical cancer

BACKGROUND/AIMS: In massive hepatic necrosis, hepatic stem cells constitute a canal of Hering derived, cytokeratin 19 (CK19) positive 'ductular reaction' (DR). Whether DRs in cirrhosis are activated stem cells (so called 'buds') or biliary metaplasia of cholestatic, injured hepatocytes is still debated. We investigate derivation of intraseptal hepatocytes (ISHs) from DRs and from the biliary tree in cirrhosis. METHODS: Explants of hepatitis B and C, alcohol, primary biliary cirrhosis and primary sclerosing cholangitis-related cirrhosis were examined. ISHs were quantified and their associations with DRs and cholestasis recorded. 3D-reconstruction of ISHs and nearby bile ducts was performed in blocks from hepatitis C and primary sclerosing cholangitis cirrhosis. RESULTS: Seven hundred seventy five/830 (94%) ISHs were associated with CK19 positive DRs. ISHs without ductular reactions were more likely to show cholestatic features (P<0.0001). In 3D, ISHs were seen to bud directly from the biliary tree. In summary: ISHs: (1) are usually associated with stem cell-like DRs; (2) are rarely cholestatic, leaving the associated DRs unexplained; and (3) are linked to the biliary tree in 3D. Dynamic proliferation rates in hepatitis C over time suggest that hepatocyte replication diminishes in late stages, with an associated activation of the biliary stem cell compartment. CONCLUSIONS: We therefore suggest that the biliary tree, from at least its smaller branches up to the canals of Hering, are composed of or at least harbor facultative hepatic stem cells, and that ISH largely represent 'buds' of newly formed hepatocytes

Infrared microspectroscopy (IR-MSP) is a spectroscopic technique that is able to monitor cell differentiation, maturation, and progression through the cell cycle. In order to establish this technique as a diagnostic tool in cellular biology and pharmacology, spectral patterns indicative of the stages of cell proliferation need to be collected. Thus, we have embarked on a systematic study of the effects of cell division and cell cycle progression on the infrared spectra of cells. In this paper, we modulated the level of cell proliferation and report the effects of this modulation on the observed infrared spectra of the cells. The modulation was achieved by serum deprivation of the growing cells, or by having the cell culture reach confluence. The progression of the cells through the cell cycle was monitored via flow cytometry, and correlated with changes in IR-MSP features in the spectral signatures due to nucleic acids (1250-1000 cm(-1)). In both these experiments, the majority of cells are in the G0/G1 stages,(3) with only a small percentage in the S and G2 phases. Nevertheless. spectral differences could be observed and interpreted in terms of the spectral changes of cellular DNA. (C) 2003 Published by Elsevier Science B.V