Characterization of a Hg2+-Selective Fluorescent Probe Based on Rhodamine B and Its Imaging in Living Cells

A small organic molecule P was synthesized and characterized as a fluorometric and colorimetric dual-modal probe for Hg2+. The sensing characteristics of the proposed probe for Hg2+ were studied in detail. A fluorescent enhancing property at 583 nm (>30 fold) accompanied with a visible colorimetric change, from colorless to pink, was observed with the addition of Hg2+ to P in an ethanol-water solution (8:2, v/v, 20 mM HEPES, pH 7.0), which would be helpful to fabricate Hg2+-selective probes with "naked-eye" and fluorescent detection. Meanwhile, cellular experimental results demonstrated its low cytotoxicity and good biocompatibility, and the application of P for imaging of Hg2+ in living cells was satisfactory.

Coefficient of variation as an image-intensity metric for cytoskeleton bundling

The evaluation of cytoskeletal bundling is a fundamental experimental method in the field of cell biology. Although the skewness of the pixel intensity distribution derived from fluorescently-labeled cytoskeletons has been widely used as a metric to evaluate the degree of bundling in digital microscopy images, its versatility has not been fully validated. Here, we applied the coefficient of variation (CV) of intensity values as an alternative metric, and compared its performance with skewness. In synthetic images representing extremely bundled conditions, the CV successfully detected degrees of bundling that could not be distinguished by skewness. On actual microscopy images, CV was better than skewness, especially on variable-angle epifluorescence microscopic images or stimulated emission depletion and confocal microscopy images of very small areas of around 1 μm2. When blur or noise was added to synthetic images, CV was found to be robust to blur but deleteriously affected by noise, whereas skewness was robust to noise but deleteriously affected by blur. For confocal images, CV and skewness showed similar sensitivity to noise, possibly because optical blurring is often present in microscopy images. Therefore, in practical use with actual microscopy images, CV may be more appropriate than skewness, unless the image is extremely noisy.

Doxorubicin induces large-scale and differential H2A and H2B redistribution in live cells

We observed prominent effects of doxorubicin (Dox), an anthracycline widely used in anti-cancer therapy, on the aggregation and intracellular distribution of both partners of the H2A-H2B dimer, with marked differences between the two histones. Histone aggregation, assessed by Laser Scanning Cytometry via the retention of the aggregates in isolated nuclei, was observed in the case of H2A. The dominant effect of the anthracycline on H2B was its massive accumulation in the cytoplasm of the Jurkat leukemia cells concomitant with its disappearance from the nuclei, detected by confocal microscopy and mass spectrometry. A similar effect of the anthracycline was observed in primary human lymphoid cells, and also in monocyte-derived dendritic cells that harbor an unusually high amount of H2B in their cytoplasm even in the absence of Dox treatment. The nucleo-cytoplasmic translocation of H2B was not affected by inhibitors of major biochemical pathways or the nuclear export inhibitor leptomycin B, but it was completely diminished by PYR-41, an inhibitor with pleiotropic effects on protein degradation pathways. Dox and PYR-41 acted synergistically according to isobologram analyses of cytotoxicity. These large-scale effects were detected already at Dox concentrations that may be reached in the typical clinical settings, therefore they can contribute both to the anti-cancer mechanism and to the side-effects of this anthracycline.

A homogeneous SIRPα-CD47 cell-based, ligand-binding assay: Utility for small molecule drug development in immuno-oncology

CD47 is an immune checkpoint protein that downregulates both the innate and adaptive anti-tumor immune response via its counter receptor SIRPα. Biologics, including humanized CD47 monoclonal antibodies and decoy SIRPα receptors, that block the SIRPα-CD47 interaction, are currently being developed as cancer immunotherapy agents. However, adverse side effects and limited penetration of tumor tissue associated with their structure and large size may impede their clinical application. We recently developed a quantitative high throughput screening assay platform to identify small molecules that disrupt the binding of SIRPα and CD47 as an alternative approach to these protein-based therapeutics. Here, we report on the development and optimization of a cell-based binding assay to validate active small molecules from our biochemical screening effort. This assay has a low volume, high capacity homogenous format that relies on laser scanning cytometry (LSC) and associated techniques to enhance signal to noise measurement of cell surface binding. The LSC assay is specific, concentration dependent, and validated for the two major human SIRPα variants (V1 and V2), with results that parallel those of our biochemical data as well as published studies. We also utilized the LSC assay to confirm published studies showing that the inhibition of amino-terminal pyroglutamate formation on CD47 using the glutaminyl cyclase inhibitor SEN177 disrupts SIRPα binding. The SIRPα-CD47 interaction could be quantitatively measured in live and fixed tumor cells. Use of fixed cells reduces the burden of cell maintenance and provides stable cell standards to control for inter- and intra-assay variations. We also demonstrate the utility of the assay to characterize the activity of the first reported small molecule antagonists of the SIRPα-CD47 interaction. This assay will support the screening of thousands of compounds to identify or validate active small molecules as hits, develop structure activity relationships and assist in the optimization of hits to leads by a typical iterative medicinal chemistry campaign.

Visualization of Annular Gap Junction Vesicle Processing: The Interplay Between Annular Gap Junctions and Mitochondria

It is becoming clear that in addition to gap junctions playing a role in cell⁻cell communication, gap junction proteins (connexins) located in cytoplasmic compartments may have other important functions. Mitochondrial connexin 43 (Cx43) is increased after ischemic preconditioning and has been suggested to play a protective role in the heart. How Cx43 traffics to the mitochondria and the interactions of mitochondria with other Cx43-containing structures are unclear. In this study, immunocytochemical, super-resolution, and transmission electron microscopy were used to detect cytoplasmic Cx43-containing structures and to demonstrate their interactions with other cytoplasmic organelles. The most prominent cytoplasmic Cx43-containing structures-annular gap junctions-were demonstrated to form intimate associations with lysosomes as well as with mitochondria. Surprisingly, the frequency of associations between mitochondria and annular gap junctions was greater than that between lysosomes and annular gap junctions. The benefits of annular gap junction/mitochondrial associations are not known. However, it is tempting to suggest, among other possibilities, that the contact between annular gap junction vesicles and mitochondria facilitates Cx43 delivery to the mitochondria. Furthermore, it points to the need for investigating annular gap junctions as more than only vesicles destined for degradation.

A microfluidic oxygen gradient demonstrates differential activation of the hypoxia-regulated transcription factors HIF-1α and HIF-2α

Gas-perfused microchannels generated a linear oxygen gradient via diffusion across a 100 μm polydimethylsiloxane (PDMS) membrane. The device enabled exposure of a single monolayer of cells sharing culture media to a heterogeneous oxygen landscape, thus reflecting the oxygen gradients found at the microscale in the physiological setting and allowing for the real-time exchange of paracrine factors and metabolites between cells exposed to varying oxygen levels. By tuning the distance between two gas supply channels, the slope of the oxygen gradient was controlled. We studied the hypoxic activation of the transcription factors HIF-1α and HIF-2α in human endothelial cells within a spatial linear gradient of oxygen. Quantification of the nuclear to cytosolic ratio of HIF immunofluorescent staining demonstrated that the threshold for HIF-1α activation was below 2.5% O2 while HIF-2α was activated throughout the entire linear gradient. We show for the first time HIF-2α is subject to hyproxya, hypoxia by proxy, wherein hypoxic cells activate HIF in close-proximity normoxic cells. These results underscore the differences between HIF-1α and HIF-2α regulation and suggest that a microfluidic oxygen gradient is a novel tool for identifying distinct hypoxic signaling activation and interactions between differentially oxygenated cells.

Scaling up multiphoton neural scanning: the SSA algorithm

In order to reverse-engineer the information processing capabilities of the cortical circuit, we need to densely sample neural circuit; it may be necessary to sample the activity of thousands of neurons simultaneously. Frame scanning techniques do not scale well in this regard, due to the time "wasted" scanning extracellular space. For scanners in which inertia can be neglected, path length minimization strategies enable large populations to be imaged at relatively high sampling rates. However, in a standard multiphoton microscope, the scanners responsible for beam deflection are inertial, indicating that an optimal solution should take rotor and mirror momentum into account. We therefore characterized the galvanometric scanners of a commercial multiphoton microscope, in order to develop and validate a MATLAB model of microscope scanning dynamics. We tested the model by simulating scan paths across pseudo-randomly positioned neuronal populations of differing neuronal density and field of view. This model motivated the development of a novel scanning algorithm, Adaptive Spiral Scanning (SSA), in which the radius of a circular trajectory is constantly updated such that it follows a spiral trajectory scanning all the cells. Due to the kinematic efficiency of near-circular trajectories, this algorithm achieves higher sampling rates than shortest path approaches, while retaining a relatively efficient coverage fraction in comparison to raster or resonance based frame-scanning approaches.

Berberine suppresses gero-conversion from cell cycle arrest to senescence

Berberine (BRB), a natural alkaloid, has a long history of medicinal use in both Ayurvedic and old Chinese medicine. Recently, available as a dietary supplement, Berberine is reported to have application in treatment of variety diseases. Previously we observed that BRB inhibited mTOR/S6 signaling concurrently with reduction of the level of endogenous oxidants and constitutive DNA damage response. We currently tested whether Berberine can affect premature, stress-induced cellular senescence caused by mitoxantrone. The depth of senescence was quantitatively measured by morphometric parameters, senescence-associated β-galactosidase, induction of p21WAF1, replication stress (γH2AX expression), and mTOR signaling; the latter revealed by ribosomal S6 protein (rpS6) phosphorylation. All these markers of senescence were distinctly diminished, in a concentration-dependent manner, by Berberine. In view of the evidence that BRB localizes in mitochondria, inhibits respiratory electron chain and activates AMPK, the observed attenuation of the replication stress-induced cellular senescence most likely is mediated by AMPK that leads to inhibition of mTOR signaling. In support of this mechanism is the observation that rhodamine123, the cationic probe targeting mitochondrial electron chain, also suppressed rpS6 phosphorylation. The present findings reveal that: (a) in cells induced to senescence BRB exhibits gero-suppressive properties by means of mTOR/S6 inhibition; (b) in parallel, BRB reduces the level of constitutive DNA damage response, previously shown to report oxidative DNA damage by endogenous ROS; (c) there appears to a causal linkage between the (a) and (b) activities; (d) the in vitro model of premature stress-induced senescence can be used to assess effectiveness of potential gero-suppressive agents targeting mTOR/S6 and ROS signaling; (e) since most of the reported beneficial effects of BRB are in age-relate diseases, it is likely that gero-suppression is the primary activity of this traditional medicine.

Risk assessment of esophageal adenocarcinoma using γ-H2AX assay

BACKGROUND

Mutagen-induced DNA damage as measured in peripheral blood lymphocytes (PBL) has been associated with increased risks of cancers. The formation of γ-H2AX is an early cellular response to DNA double-strand breaks (DSB). We hypothesize that higher level of radiation-induced γ-H2AX in PBLs may be associated with an increased risk of esophageal adenocarcinoma.

METHODS

Laser scanning cytometer-based immunocytochemical method was used to measure baseline and irradiation-induced γ-H2AX levels in PBLs from 211 patients with esophageal adenocarcinoma and 211 healthy controls. The ratio of induced γ-H2AX level to baseline level was used to evaluate individual susceptibility to DSBs. Relative risks for esophageal adenocarcinoma associated with γ-H2AX were assessed by multivariable logistic regression analysis.

RESULTS

Radiation-induced γ-H2AX level and the γ-H2AX ratio were significantly higher in cases than in controls. Dichotomized at the median in controls, a significantly increased risk for esophageal adenocarcinoma was observed in association with high γ-H2AX ratio [OR = 2.94; 95% confidence interval (CI), 1.83-4.72]. Quartile analyses showed significant dose-response associations between higher γ-H2AX ratio and increased risk of esophageal adenocarcinoma (Ptrend, 1.64E-06). In addition, joint effect between γ-H2AX ratio and smoking was observed: smokers who had high γ-H2AX ratio exhibited the highest risk of esophageal adenocarcinoma (OR = 5.53; 95% CI, 2.71-11.25) compared with never smokers with low γ-H2AX ratio.

CONCLUSION

Radiation-induced DNA damage assessed by γ-H2AX ratio is associated with an increased risk of esophageal adenocarcinoma.

IMPACT

γ-H2AX assay is a new and robust method to measure DSB damage in PBLs, which can be used to assess mutagen sensitivity and esophageal adenocarcinoma risk.

Direct and indirect QMRA of infectious Cryptosporidium oocysts in reclaimed water

Water scarcity leads to an increased use of reclaimed water, which in turn calls for an improvement in water reclamation procedures to ensure adequate quality of the final effluent. The presence of infectious Cryptosporidium oocysts (IOO) in reclaimed water is a health hazard for users of this resource. Here, we gathered information on Cryptosporidium (concentrations, infectivity and genotype) in order to perform quantitative microbial risk assessment (QMRA). Moreover, data concerning the spores of sulphite-reducing clostridia (SRC) were used to undertake QMRA at a screening level. Our results show that the probability of infection (PI) by Cryptosporidium depends on the tertiary treatment type. The mean PI using the exponential dose-response model was 3.69 × 10(-6) in tertiary effluents (TE) treated with UV light, whereas it was 3 log(10) units higher, 1.89 × 10(-3), in TE not treated with this disinfection method. With the β-Poisson model, the mean PI was 1.56 × 10(-4) in UV-treated TE and 2 log(10) units higher, 4.37 × 10(-2), in TE not treated with UV. The use of SRC to perform QMRA of Cryptosporidium showed higher PI than when using directly IOO data. This observation suggests the former technique is a conservative method of QMRA.

Green Tea Polyphenol Epigallocatechin Gallate Inhibits Adipogenesis and Induces Apoptosis in 3T3-L1 Adipocytes

OBJECTIVE

Green tea catechins have been shown to promote loss of body fat and to inhibit growth of many cancer cell types by inducing apoptosis. The objective of this study was to determine whether epigallocatechin gallate (EGCG), the primary green tea catechin, could act directly on adipocytes to inhibit adipogenesis and induce apoptosis.

RESEARCH METHODS AND PROCEDURES

Mouse 3T3-L1 preadipocytes and mature adipocytes were used. To test the effect of EGCG on viability, cells were incubated for 3, 6, 12, or 24 hours with 0, 50, 100, or 200 microM EGCG. Viability was quantitated by MTS assay. To determine the effect of EGCG on apoptosis, adipocytes were incubated for 24 hours with 0 to 200 microM EGCG, then stained with annexin V and propidium iodide and analyzed by laser scanning cytometry. Both preadipocytes and adipocytes were also analyzed for apoptosis by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. To determine the effect of EGCG on adipogenesis, maturing preadipocytes were incubated during the 6-day induction period with 0 to 200 microM EGCG, then stained with Oil-Red-O and analyzed for lipid content.

RESULTS

EGCG had no effect on either viability or apoptosis of preconfluent preadipocytes. EGCG also did not affect viability of mature adipocytes; however, EGCG increased apoptosis in mature adipocytes, as demonstrated by both laser scanning cytometry and terminal deoxynucleotidyl transferase dUTP nick-end labeling assays. Furthermore, EGCG dose-dependently inhibited lipid accumulation in maturing preadipocytes.

DISCUSSION

These results demonstrate that EGCG can act directly to inhibit differentiation of preadipocytes and to induce apoptosis of mature adipocytes and, thus, could be an important adjunct in the treatment of obesity.

New techniques in imaging in Barrett's esophagus

The presence of dysplasia in patients with Barrett's esophagus identifies who is at increased risk for the development of esophageal adenocarcinoma and who may most benefit from intervention. Several technologies have emerged as potent tools to identify subtle or occult neoplasia in the gastrointestinal tract. Detailed inspection of the mucosa with high resolution white light endoscopy is the most critical tool to detect subtle neoplasia. This review also chromoendoscopy, narrow band imaging, autofluorescence imaging, optical coherence tomography, confocal laser endomicroscopy, and spectroscopy in the context of detection of neoplasia in Barrett's esophagus.

Identification of PDGFRα positive populations of interstitial cells in human and guinea pig bladders

PURPOSE

The bladder wall comprises a complex array of cells, including urothelium, smooth muscle, nerves and interstitial cells. Interstitial cells have several subtypes based on site, morphology and differential expression of markers such as anti-vimentin and anti-KIT. We examined whether a subpopulation of interstitial cells immunopositive for PDGFRα exists in human and guinea pig bladders.

MATERIALS AND METHODS

Human and guinea pig bladder tissues were processed for immunohistochemistry and examined by bright field or confocal microscopy. Whole mount tissues and paraffin sections were labeled with antibodies to PDGFRα, vimentin, KIT and PGP9.5. Protein expression was assessed by Western blot.

RESULTS

PDGFRα(+) cells were present in human and guinea pig bladders. In the guinea pig PDGFRα(+) cells had a branched stellate morphology and formed networks in the lamina propria. In human and guinea pig detrusors PDGFRα(+) cells were elongated on the boundary of smooth muscle bundles or were seen as groups of stellate cells in the interbundle spaces. PDGFRα(+) cells were located close to nerves labeled by PGP9.5. Double labeling revealed that PDGFRα(+) cells were a subgroup of the vimentin(+) population. A significant proportion of PDGFRα(+) cells were also KIT(+). Bands corresponding to PDGFRα, KIT and vimentin proteins were detected on Western blot.

CONCLUSIONS

To our knowledge this study is the first to identify PDGFRα(+)/KIT(+) cells in the bladder lamina propria and detrusor layers. These cells are a subgroup of the vimentin(+) population, showing the complexity of bladder interstitial cells. PDGFRα(+) cells are apparently structurally associated with intramural nerves, indicating integration with bladder control mechanisms.

The Gαq/11 proteins contribute to T lymphocyte migration by promoting turnover of integrin LFA-1 through recycling

The role of Gαi proteins coupled to chemokine receptors in directed migration of immune cells is well understood. In this study we show that the separate class of Gαq/11 proteins is required for the underlying ability of T cells to migrate both randomly and in a directed chemokine-dependent manner. Interfering with Gαq or Gα11 using dominant negative cDNA constructs or siRNA for Gαq causes accumulation of LFA-1 adhesions and stalled migration. Gαq/11 has an impact on LFA-1 expression at plasma membrane level and also on its internalization. Additionally Gαq co-localizes with LFA-1- and EEA1-expressing intracellular vesicles and partially with Rap1- but not Rab11-expressing vesicles. However the influence of Gαq is not confined to the vesicles that express it, as its reduction alters intracellular trafficking of other vesicles involved in recycling. In summary vesicle-associated Gαq/11 is required for the turnover of LFA-1 adhesion that is necessary for migration. These G proteins participate directly in the initial phase of recycling and this has an impact on later stages of the endo-exocytic pathway.

Laser scanning cytometry: principles and applications-an update

Laser scanning cytometer (LSC) is the microscope-based cytofluorometer that offers a plethora of unique analytical capabilities, not provided by flow cytometry (FCM). This review describes attributes of LSC and covers its numerous applications derived from plentitude of the parameters that can be measured. Among many LSC applications the following are emphasized: (a) assessment of chromatin condensation to identify mitotic, apoptotic cells, or senescent cells; (b) detection of nuclear or mitochondrial translocation of critical factors such as NF-κB, p53, or Bax; (c) semi-automatic scoring of micronuclei in mutagenicity assays; (d) analysis of fluorescence in situ hybridization (FISH) and use of the FISH analysis attribute to measure other punctuate fluorescence patterns such as γH2AX foci or receptor clustering; (e) enumeration and morphometry of nucleoli and other cell organelles; (f) analysis of progeny of individual cells in clonogenicity assay; (g) cell immunophenotyping; (h) imaging, visual examination, or sequential analysis using different probes of the same cells upon their relocation; (i) in situ enzyme kinetics, drug uptake, and other time-resolved processes; (j) analysis of tissue section architecture using fluorescent and chromogenic probes; (k) application for hypocellular samples (needle aspirate, spinal fluid, etc.); and (l) other clinical applications. Advantages and limitations of LSC are discussed and compared with FCM.

Photothermal multispectral image cytometry for quantitative histology of nanoparticles and micrometastasis in intact, stained and selectively burned tissues

There is a rapidly growing interest in the advanced analysis of histological data and the development of appropriate detection technologies in particular for mapping of nanoparticle distributions in tissue in nanomedicine applications. We evaluated photothermal (PT) scanning cytometry for color-coded imaging, spectral identification, and quantitative detection of individual nanoparticles and abnormal cells in histological samples with and without staining. Using this tool, individual carbon nanotubes, gold nanorods, and melanoma cells with intrinsic melanin markers were identified in unstained (e.g. sentinel lymph nodes) and conventionally-stained tissues. In addition, we introduced a spectral burning technique for histology through selective laser bleaching areas with nondesired absorption background and nanobubble-based PT signal amplification. The obtained data demonstrated the promise of PT cytometry in the analysis of low-absorption samples and mapping of various individual nanoparticles' distribution that would be impossible with existing assays. Comparison of PT cytometry and photoacoustic (PA) cytometry previously developed by us, revealed that these methods supplement each other with a sensitivity advantage (up to 10-fold) of contactless PT technique in assessment of thin (≤100 μm) histological samples, while PA imaging provides characterization of thicker samples which, however, requires an acoustic contact with transducers. A potential of high-speed integrated PT-PA cytometry for express histology and immunohistochemistry of both intact and stained heterogeneous tissues with high sensitivity at the zepromolar concentration level is further highlighted.

Comparison of two techniques for the screening of human tumor cells in mouse blood: quantitative real-time polymerase chain reaction (qRT-PCR) versus laser scanning cytometry (LSC)

The formation of metastases is often investigated in xenografted human tumors in mice and the need arises to detect disseminated human tumor cells in small volumes of mouse blood. Two techniques, namely quantitative real-time polymerase chain reaction (qRT-PCR) and laser scanning cytometry (LSC), were compared for screening of 100 microl blood samples from immunodeficient mice spiked with a defined number of human HT29 colon carcinoma cells. With both techniques (qRT-PCR for amplifying of human Alu-sequences and LSC techniques for screening of fluorescence labelled cells), it was possible to detect single disseminated human tumor cells. Using the qRT-PCR technique, a recovery rate of nearly 100% was found when 10-10,000 cells were added to 100 microl blood. In contrast, the median recovery rate of the LSC technique varied between 20% (10 cells/100 microl blood) and 7.5% (10,000 cells/100 microl blood). Thus, it is advisable to quantify the number of human tumor cells in mouse blood by qRT-PCR and to use LSC for phenotyping of disseminated tumor cells only.

BRCA1 protein and nucleolin colocalize in breast carcinoma tissue and cancer cell lines

The breast and ovarian cancer susceptibility gene BRCA1 encodes a tumor suppressor. BRCA1 protein, which is involved in DNA damage response, has been thought to be found primarily in cell nuclei. In the present investigation, immunohistological studies of BRCA1 protein in frozen breast cancer tissue and MCF7 and HeLa cell lines revealed BRCA1 expression in both nucleoli and nucleoplasmic foci. Immunoelectron microscopic studies of estrogen-stimulated MCF7 cells demonstrated BRCA1 protein localization in the granular components of the nucleolus. Moreover, immunofluorescence of BRCA1 and nucleolin double-labeling showed colocalization in both nucleoli and nucleoplasmic foci in breast tumor cells and asynchronously growing MCF7 and HeLa cells. Multiparameter analysis of BRCA1 and nucleolin in relation to cell cycle position (DNA content) showed expression during G1-S and persistence of BRCA1 during G2/M. After gamma-irradiation of MCF7 cells, BRCA1 protein dispersed from nucleoli and nucleoplasmic foci to other nucleoplasmic sites, which did not colocalize with nucleolin. Small interfering RNA-mediated knockdown of BRCA1 protein resulted in decreased immunofluorescence staining, which was confirmed by Western blotting. The observed colocalization of BRCA1 and nucleolin raises new possibilities for the nucleoplasm-nucleolus pathways of these proteins and their functional significance.

Chromatin texture, DNA index, and S-phase fraction in primary breast carcinoma cells analysed by laserscanning cytometry

OBJECTIVES

Laser scanning cytometry (LSC) is a slide-based technique capable of measuring a number of biological parameters both in immobilised cell suspensions and in formalin-fixed paraffin-embedded tissue sections.

BACKGROUND

High proliferation rate in surgically removed breast tumours is an unfavourable prognostic factor. In node negative cases it can help distinguish patients with higher risk for distant metastases from those with a lower risk.

PATIENTS AND METHODS

In a prospective study we investigated 140 breast tumours, of which 113 were invasive ductal carcinomas, 11 were invasive lobular carcinomas, and 16 tumours were of other histological types. Cells for LSC investigations were prepared from fresh, surgically removed tumours by mechanical disintegration. After fixation the cells were stained with FITC-conjugated anti-cytokeratin (CK-FITC) to distinguish CK+ tumour cells from CK- stroma, and with propidium iodide to stain DNA.

RESULTS

We identified three S-phase fraction (SPF) groups, with low (30 patients), moderate (54 patients), and high SPF (51 patients). Thirty-seven tumours were diploid, 83 were aneuploid, while 5 tumours had a bimodal distribution of DNA content. Chromatin texture values were increasing in the respective subclasses from the hypodiploid group to the tetraploid/hypertetraploid group.

CONCLUSION

The measurement of DNA content and SPF of tumours by LSC completed by and correlated with other biological properties of the tumour cells may be a useful tool in assessing prognosis and clinical outcome of patients with breast cancer. (Tab. 5, Fig. 4, Ref. 18). Full Text (Free, PDF) www.bmj.sk.

Advanced detection and measurement of cells on membrane from peripheral blood by laser scanning cytometry (LSC) in early stage breast cancer patients

BACKGROUND

The aim of our study was the potential detection of circulating tumour cells (CTCs) in early stage breast cancer patients. Our approach was cell microfiltration through polycarbonate membrane as a concentration method suitable for CTC selection in peripheral blood. The isolated cells on membrane were further analysed by laser scanning cytometry.

METHODS

Sixteen patients were enrolled in the study, of which 13 had early stage breast carcinoma and 3 patients had metastatic breast carcinoma. The analyses were performed from 9 ml of peripheral blood, in one patient blood was drawn twice. Blood samples were taken after adjuvant chemotherapy but prior to adjuvant radiotherapy. The control group consisted of 12 clinically healthy subjects.

CONCLUSIONS

In the control group 3 subjects out of 12 had 1 CTC, the mean CTC numbers being 0.25 +/- 0.45. In the early stage breast cancer patients 0-36 CTCs were detected (mean 13.9 +/- 12.9 CTCs. 10 patients out of 13 had more than 2 CTCs (62%). The detection and measurement of cells on membrane is a simple and reproducible method of detection of CTCs in peripheral blood. Sensitivity of the method is 88.5%. Detection of CTCs seems to be a promising method for the monitoring of adjuvant therapy in early stage breast cancer patients and for the identification of high risk patients in whom elevated numbers of CTCs are persisting following the termination of adjuvant therapy (Tab. 1, Fig. 4, Ref. 35). Full Text (Free, PDF) www.bmj.sk.

Vascular endothelial growth factor expression in peritoneal mesothelial cells undergoing transdifferentiation

OBJECTIVE

To analyze gene expression of localized peritoneal tissue structures in a rodent model of peritoneal fibrosis.

METHODS

Female Sprague Dawley rats were treated with an intraperitoneal injection of an adenovirus expressing active transforming growth factor-beta or control adenovirus. Four and 7 days after infection, animals were sacrificed and frozen sections of parietal peritoneum were subjected to immunofluorescence-aided laser capture microdissection in order to isolate vascular, mesothelial, and submesothelial structures. RNA was extracted from microdissected tissue and gene expression was analyzed by quantitative reverse-transcript polymerase chain reaction. We analyzed genes involved in angiogenesis, epithelial-to-mesenchymal transdifferentiation, and fibrosis. Vascular endothelial growth factor and alpha-smooth muscle actin expression was analyzed with immunohistochemistry of formalin-fixed tissue.

RESULTS

Transforming growth factor-beta(1) induced expression of Snail and alpha-smooth muscle actin genes in the peritoneal mesothelium. This same cell population also demonstrated increased gene expression of vascular endothelial growth factor. The distribution of this growth factor was confirmed by immunohistochemistry. The fibrogenic growth factor, connective tissue growth factor, was also strongly induced in the peritoneal mesothelium.

CONCLUSIONS

Using immunofluorescence-aided laser capture microdissection, we were able to study gene expression in subcompartments of the peritoneal tissue. We demonstrated that mesothelial cells exhibiting mesenchymal transdifferentiation are associated with increased expression of genes associated with fibrosis and angiogenesis.

Cryotops versus open-pulled straws (OPS) as carriers for the cryopreservation of bovine oocytes: effects on spindle and chromosome configuration and embryo development

Two experiments were designed to assess the effectiveness of cryopreserving bovine MII oocytes using cryotops as the carrier system for vitrification. In the first experiment, we examined the developmental competence of oocytes after: (i) vitrification in open-pulled straws (OPS method); or (ii) vitrification in <0.1mul medium droplet on the surface of a specially constructed fine polypropylene strip attached to a plastic handle (Cryotop method). In the second experiment, warmed oocytes that had been vitrified in OPS or cryotops were fixed to analyze spindle and chromosome configuration. In all experiments both cow and calf oocytes were used. Significantly different fertilization rates were observed between the vitrification groups: 31.5% and 20.2% for the cow and calf oocytes vitrified in OPS, respectively, versus 46.1% and 46.4% for the oocytes vitrified using cryotops. After in vitro fertilization, 3.8% of the calf oocytes and 5.3% of the cow oocytes developed to the blastocyst stage. All blastocysts from vitrified oocytes resulted from the Cryotop method. A significantly lower percentage of the OPS-vitrified calf oocytes showed a normal spindle configuration (37.8%) compared to control fresh oocytes (69.9%), while normal spindle and chromosome configurations were observed in a significantly higher proportion of the cryotop-vitrified calf oocytes (60.2%). For the cow oocytes, 60.6% in the OPS group and 60.3% in the Cryotop group exhibited a normal morphology after warming. These findings suggest the cryotop system is a more efficient carrier for vitrification than OPS for the cryopreservation of bovine oocytes.

Lack of inducible nitric oxide synthases attenuates leukocyte-endothelial cell interactions in retinal microcirculation

Aim:

To investigate the effect of inducible nitric oxide synthases (iNOS) on inflammatory reactions during endotoxin-induced uveitis (EIU) in mice by studying leukocyte–endothelial cell interactions.

Methods:

EIU was produced in immunosuppressed iNOS^−/− mice and C57BL/6 (normal) mice by footpad injection of lipopolysaccharide. Leukocytes were labelled with acridine orange. Leukocyte rolling in the retinal microcirculation was evaluated in vivo with acridine orange digital fluorography. The number of migrated leukocytes was counted in flat-mounted retina.

Results:

Both leukocyte rolling and migration peaked at 48 h after lipopolysaccharide injection. The maximal numbers of rolling leukocytes in the immunosuppressed iNOS^−/− mouse retina decreased by 98.2% (p<0.001) compared with that in the normal mouse retina at 48 h after lipopolysaccharide injection. In addition, the maximal numbers of migrated leukocytes in the immunosuppressed iNOS^−/− mouse retina decreased by 74.0% (p<0.001) compared with that in the normal mouse retina at 24 h after lipopolysaccharide injection. Furthermore, the diameters of major retinal veins of the immunosuppressed iNOS^−/− group were smaller at both 24 and 48 h after lipopolysaccharide injection than were those of the normal group (p<0.001, respectively).

Conclusions:

A lack of iNOS suppresses leukocyte–endothelial cell interactions in the retinas of mice with EIU. This suggests that iNOS may play a role in the management of patients with uveitis and other inflammatory conditions.

Laser scanning cytometry (LSC) in pathology--a perspective tool for the future?

Cytometry is becoming a standard method of examination not only in biology but also in various fields of experimental and clinical medicine. While in flow cytometry suspensions of cells are measured, laser scanning cytometers enable both the measurement of cells in single-cell suspensions (after immobilising the cells on a conventional glass slide) and in frozen or paraffin-embedded tissue sections. We discuss the possible fields of utilisation and future perspectives of laser scanning cytometry in medicine with special reference to clinical pathology and cytology (Fig. 3, Ref. 49). Full Text (Free, PDF) www.bmj.sk.

Interaction of cyanide and nitric oxide with cytochrome c oxidase: implications for acute cyanide toxicity

Acute cyanide toxicity is attributed to inhibition of cytochrome c oxidase (CcOX), the oxygen-reducing component of mitochondrial electron transport; however, the mitochondrial action of cyanide is complex and not completely understood. State-3 oxygen consumption and CcOX activity were studied in rat N27 mesencephalic cells to examine the functional interaction of cyanide and nitric oxide (NO). KCN produced a concentration-dependent inhibition of cellular respiration. Cyanide's median inhibitory concentration (IC50) of oxygen consumption (13.2 +/- 1.8microM) was higher than the CcOX IC50 (7.2 +/- 0.1microM). Based on respiratory threshold analysis, 60% inhibition of CcOX was necessary before oxygen consumption was decreased. Addition of high levels of exogenous NO (100microM S-nitroso-N-acetyl-DL-penicillamine) attenuated cyanide inhibition of both respiration and CcOX. On the other hand, when endogenous NO generation was blocked by an NOS inhibitor (N(omega)-monomethyl-L-arginine ester), the cyanide IC50 for both respiration and CcOX increased to 59.6 +/- 0.9microM and 102 +/- 10microM, respectively, thus showing constitutive, low-level NO production enhanced cyanide inhibition. Laser scanning cytometry showed that cyanide elevated mitochondrial NO, which then was available to interact with CcOX to enhance the inhibition. It is concluded that the rapid, potent action of cyanide is due in part to mitochondrial generation of NO, which enhances inhibition of CcOX. At low mitochondrial oxygen tensions, the cyanide-NO interaction would be increased. Also, the antidotal action of sodium nitrite is partly explained by generation of high mitochondrial levels of NO, which antagonizes the CcOX inhibition.

Noninvasive intravital imaging of thymocyte dynamics in medaka

In vivo imaging of thymocytes has not been accomplished due to their localization deep within opaque body and high susceptibility to surgical stress. To overcome these problems, medaka is useful because of transparency and ex-uterine development. We report the noninvasive detection of thymocytes in transgenic medaka that express fluorescent protein under the control of immature-lymphocyte-specific rag1. We show that lymphoid progenitor cells colonize the thymus primordium in an anterior-to-posterior orientation-specific manner, revealing that extrathymic anterior components guide prevascular thymus colonization. We also show that developing thymocytes acquire "random walk motility" along with the expression of Ag receptors and coreceptors, suggesting that thymocyte walking is initiated at the developmental stage for repertoire selection. Thus, transgenic medaka enables real-time intravital imaging of thymocytes without surgical invasion.

Correlation of malignant phenotypes of human tumour cell lines with augmented expression of Hsp72 protein measured by laser scanning cytometry

Augmented expression of members of the heat shock protein 70 (Hsp70) family are frequently observed in various human cancers. In this study, we examined applicability of laser scanning cytometer (LSC) to evaluate the level of Hsp72, which is the member constitutively expressed and significantly induced after heat shock, in human tumour cell lines. The relative nuclear content of Hsp72 measured by LSC correlated well with the relative intracellular content determined by Western blotting (R = 0.906). Furthermore, there was a close relationship between the relative nuclear content of Hsp72 measured by LSC and the colony-forming ability in soft agar, one of the malignant characteristics of tumour cells (R = 0.880). These results indicate that LSC measurement is useful for predicting the degree of malignancy of cancer cells, as it is reliable, faster than Western blotting and more objective and quantitative than visual measurements.

Telomere dysfunction in peripheral lymphocytes as a potential predisposition factor for renal cancer

PURPOSE

Genetic integrity is maintained in part by the architecture of telomeres. We previously developed a laser scanning cytometry based quantitative fluorescence in situ hybridization assay to assess telomere length in peripheral blood lymphocytes. In this study we modified the assay by incorporating 9 control cell lines to normalize telomere length.

MATERIALS AND METHODS

We applied this assay to 65 patients with renal cell carcinoma, and 65 age, sex and ethnicity matched controls. For each subject we measured telomere length in CD4+ T cells, CD8+ T cells and overall peripheral blood lymphocytes.

RESULTS

For cases vs controls mean normalized telomere length +/- SD was 0.84 +/- 0.15 vs 0.95 +/- 0.18 for CD4+ T cells, 0.80 +/- 0.21 vs 0.95 +/- 0.22 for CD8+ T cells and 0.88 +/- 0.25 vs 0.99 +/- 0.22 for overall peripheral blood lymphocytes (each p <0.05). After adjustment for patient age, sex, ethnicity and smoking status, and using 75% of telomere length in controls as a cutoff point, short telomere length in CD4+ T cells was associated with a significantly increased risk of renal cell carcinoma (OR 3.08, 95% CI 1.14-8.34). Compared to individuals within the highest quartile of telomere length the OR for those within the 3rd, 2nd and 1st quartiles was 1.81 (95% CI 0.54-6.08), 2.15 (95% CI 0.67-6.91) and 5.41 (95% CI 1.78-16.4), respectively (p for trend <0.01). Similar trends were observed in CD8+ T cells and overall peripheral blood lymphocytes. In controls there was no significant difference among the telomere lengths of CD4+ T cells, CD8+ T cells and overall PBLs.

CONCLUSIONS

Our data argue against the possibility that telomere length difference between cancer cases and controls may be due to the variations of lymphocyte subpopulation or clonal expansion. Our data strongly support the hypothesis that telomere shortening in peripheral blood lymphocytes is a genetic predisposing factor for cancer.

TPA-induced multinucleation of a mesenchymal stem cell-like clone is mediated primarily by karyokinesis without cytokinesis, although cell-cell fusion also occurs

The 5F9A cell, which is a mesenchymal stem cell-like clone established from rat bone marrow substrate adherent cells, can differentiate into adipocytes and osteoblasts in vitro under the appropriate conditions. Multinucleated cells could be also induced by 12-O-tetradecanoylphorbol 13-acetate (TPA) in 5F9A cells. This effect was mediated by protein kinase C. Possible mechanisms of multinucleation by TPA were hypothesized to be either karyokinesis without cytokinesis or cell-cell fusion. By observation using time-lapse phase-contrast microscopy, we determined that the multinucleated cells were generated mainly by karyokinesis without cytokinesis. Cell fusion was studied using time-lapse photography, and confocal laser scanning microscopy using two differentially labeled cells. These techniques demonstrated that multinucleated 5F9A cells could be produced by cell fusion, albeit at a low frequency. We conclude that multinucleated 5F9A cells are formed primarily by karyokinesis without cytokinesis, although some cells are also formed by cell-cell fusion.

Phenotype-specific inhibition of the vascular smooth muscle cell cycle by high glucose treatment

AIMS/HYPOTHESIS

Diabetes accelerates the development of atherosclerosis, which critically involves the proliferation of vascular smooth muscle cells (SMCs). However, how high glucose treatment regulates SMC proliferation is controversial. Considering the established SMC heterogeneity, we hypothesised that glucose treatment may have distinct effects on proliferation of the various phenotypic SMCs.

MATERIALS AND METHODS

We tested this possibility using cloned spindle-shaped and epithelioid SMCs and laser scanning cytometry.

RESULTS

Our results showed that glucose treatment significantly inhibited the serum-independent proliferation of epithelioid SMCs, but had no effect on the proliferation of spindle-shaped cells either with or without serum stimulation. Furthermore, glucose treatment inhibited DNA synthesis, as detected by bromodeoxyuridine (BrdU) incorporation, and increased the production of reactive oxygen species in epithelioid SMCs. The inhibition of BrdU incorporation by glucose treatment was mimicked by glucosamine and phorbol 2,13-dibutyrate, a protein kinase C (PKC) activator, and reversed by azaserine, an inhibitor of the hexosamine pathway. In addition, the inhibitory effects of glucose treatment were blocked by GF 109203X (a PKC inhibitor) and PD98058 (a MAPK/ERK kinase, MEK inhibitor), and by knockdown of MEK1 by small interfering RNA (siRNA). The addition of either GF 109203X or PD98058 also reduced the phosphorylation of MAP kinase induced by glucose treatment.

CONCLUSIONS/INTERPRETATION

Glucose treatment inhibits the proliferation of epithelioid, but not spindle-shaped, vascular SMCs through the activation of PKC and the MAP kinase pathway, suggesting that the effects of hyperglycaemia on vascular disease depend on the phenotype of SMCs involved.

Organotypic co-cultures allow for immortalized human gingival keratinocytes to reconstitute a gingival epithelial phenotype in vitro

We report here that the organotypic co-culture (OCC) system allows for significant preservation of the tissue-specific phenotype of human gingival keratinocytes (IHGK) immortalized with the E6/E7 gene of the human papillomavirus type 16 (HPV16). The approach adopted is based on the OCC system facilitating spatially separated cell growth and cell-to-cell interactions via diffusible growth factors. Generally, IHGK reveal transcription of the HPV16 E6/E7 gene at rising passages. Fluorescence in situ hybridization performed for chromosomes 1, 8, 10, and 18 demonstrates that disomic fractions differ between the tested chromosomes but otherwise remain fairly constant. Monosomies of chromosome 18 are more prominent in late passages 81 and 83, while polysomies of chromosome 10 and 18 are detected in early passages 25 and 27. In comparison with corresponding monolayer cultures (MCs), IHGK in OCCs form stratified epithelia, proliferate, and express gingival-specific gene products in vitro. Moreover, mRNA gene transcription for growth factors interleukin 1beta, granulocyte-macrophage colony stimulating factor, fibroblast growth factor 7, and EGF in OCCs is different from that in MCs. When grafted onto nude mice, IHGK develop hyperplastic, differentiated surface epithelia devoid of malignant growth. We are not aware of any other OCC system comprising of IHGK, which allows for site-specific expression of gingival epithelial markers. This substantiates reconstitution of a gingival epithelial phenotype in vitro.

Quantitative Analysis of Melanocytic Tissue Array Reveals Inverse Correlation between Activator Protein-2α and Protease-Activated Receptor-1 Expression during Melanoma Progression

The identification of molecular markers of melanoma progression is needed to more accurately stage and identify treatments for patients with malignant melanoma. Previously, we demonstrated that loss of the activator protein-2alpha (AP-2alpha) expression results in overexpression of the protease-activated receptor-1 (PAR-1) in human melanoma cell lines. Here, we used a tissue microarray platform that consisted of 64 melanocytic lesions, including dysplastic nevi (N=21), primary melanoma (N=20), and metastatic melanoma (N=23). We analyzed the expression of AP-2 and PAR-1 simultaneously by immunofluorescent microscopy with an automated quantification laser scanning cytometer. AP-2 was highly expressed in normal cutaneous melanocytes and dysplastic nevi but not in melanoma metastases. We observed a significantly higher number of AP-2-positive cells in the dysplastic nevi (P=0.0013) and primary melanoma (P=0.0023) compared to the metastatic melanoma. In contrast, we observed a significantly higher percentage of PAR-1-positive cells in the metastatic melanoma compared to dysplastic nevi (P=0.0072) and primary melanoma (P=0.0138). Increased expression of PAR-1 in metastatic melanomas contributes to tumor progression by modulating expression of genes, such as IL-8, matrix metalloproteinase-2, vascular endothelial growth factor, platelet-derived growth factor, and integrins. These findings support our hypothesis that loss of AP-2 is a crucial event in the progression of human melanoma and contributes to the acquisition of the metastatic phenotype via upregulation of PAR-1.

Comparative study between two laser scanning cytometers and epifluorescence microscopy for the detection ofCryptosporidium oocysts in water

BACKGROUND

Cryptosporidium detection in water and environmental samples has increased during the last years, largely due to an increase in the number of reported waterborne outbreaks of cryptosporidiosis and the implementation of new regulations about Cryptosporidium monitoring in water supplies. The aim of this study was to validate and compare the capacity of two laser scanning cytometers commercially available (LSC and ChemScanRDI), against manual microscopic enumeration of Cryptosporidium oocysts in surface water and reference material samples.

METHODS

Reference material and surface water samples were analysed by two laser scanning cytometers methodologies and by manual epifluorescence microscopy. Two mAbs from commercial suppliers were used to evaluate background reduction.

RESULTS

Highly significant correlations were obtain between both cytometers (R(2) = 0.99) and with manual microscopy (R(2) = 0.98), showing that oocysts counts made by cytometers were equivalent to those obtained with conventional methods. We observed a variability in oocysts counts when different antibodies where used with laser scanning cytometers and manual microscopy.

CONCLUSIONS

This study showed the efficacy of the laser scanning technology (LSC and ChemScanRDI), as an automated and a more standardized alternative to manual epifluorescence microscopy examination, for Cryptosporidium detection in water samples. High quality antibodies are needed for automated enumeration as well as for manual microscope observations.

Dynamic imaging of dendritic cell extension into the small bowel lumen in response to epithelial cell TLR engagement

Cells lining the gastrointestinal tract serve as both a barrier to and a pathway for infectious agent entry. Dendritic cells (DCs) present in the lamina propria under the columnar villus epithelium of the small bowel extend processes across this epithelium and capture bacteria, but previous studies provided limited information on the nature of the stimuli, receptors, and signaling events involved in promoting this phenomenon. Here, we use immunohistochemical as well as dynamic explant and intravital two-photon imaging to investigate this issue. Analysis of CD11c–enhanced green fluorescent protein (EGFP) or major histocompatibility complex CII-EGFP mice revealed that the number of trans-epithelial DC extensions, many with an unusual “balloon” shape, varies along the length of the small bowel. High numbers of such extensions were found in the proximal jejunum, but only a few were present in the terminal ileum. The extensions in the terminal ileum markedly increased upon the introduction of invasive or noninvasive Salmonella organisms, and chimeric mouse studies revealed the key role of MyD88-dependent Toll-like receptor (TLR) signaling by nonhematopoietic (epithelial) elements in the DC extension response. Collectively, these findings support a model in which epithelial cell TLR signaling upon exposure to microbial stimuli induces active DC sampling of the gut lumen at sites distant from organized lymphoid tissues.

Studying the right cell in acute myelogenous leukemia: dynamic changes of apoptosis and signal transduction pathway protein expression in chemotherapy resistant ex-vivo selected "survivor cells"

We hypothesized that studying protein expression in cells surviving in vitro chemotherapy ("survivor cells", SV), could provide more important insight into the biology of drug-resistant AML cells than analysis of the bulk population of leukemic cells. Leukemia-enriched samples from 79 patients with new or relapsed AML were cultured for four days +/- cytarabine (5-10 microM). Early apoptotic cells were removed to yield purified SV. Expression of BCL2, bax, PKC alpha, ERK2 and pERK2 proteins was measured using laser scanning cytometry. The SV population was enriched for CD34+ stem cells. Protein expression patterns in SV differed considerably from those in controls; culture and reanalysis of protein expression revealed stability, reversion, or new patterns of change. Patterns of pairs or triads of proteins were nonrandomly distributed and appeared at statistically unlikely frequencies, suggesting preferential adoption of certain patterns. The patterns of change were highly predictive of remission attainment, relapse, and survival in univariate and multivariate analysis. We conclude that in vitro SV cells have protein expression patterns distinct from those of the bulk population of leukemic cells and that these patterns are predictive of outcome. Analysis of SV cells may be more informative than analysis of the bulk population of leukemia cells.

Spatial distributions of Kv4 channels and KChip2 isoforms in the murine heart based on laser capture microdissection

OBJECTIVE

Regional differences in repolarizing K(+) current densities and expression levels of their molecular components are important for coordinating the pattern of electrical excitation and repolarization of the heart. The small size of hearts from mice may obscure these interventricular and/or transmural expression differences of K(+) channels. We have examined this possibility in adult mouse ventricle using a technology that provides very high spatial resolution of tissue collection.

METHODS

Conventional manual dissection and laser capture microdissection (LCM) were utilized to dissect tissue from distinct ventricular regions. RNA was isolated from epicardial, mid-myocardial and endocardial layers of both the right and left ventricles. Real-time RT-PCR was used to quantify the transcript expression in these different regions.

RESULTS

LCM revealed significant interventricular and transmural gradients for both Kv4.2 and the alpha-subunit of KChIP2. The expression profile of a second K(+) channel transcript, Kir2.1, which is responsible for the inwardly rectifying K(+) current I(k1), showed no interventricular or transmural gradients and therefore served as a negative control.

CONCLUSIONS

Our findings are in contrast to previous reports of a relatively uniform left ventricular transmural pattern of expression of Kv4.2, Kv4.3 and KChIP2 in adult mouse heart, which appear to be different than that in larger mammals. Specifically, our results demonstrate significant epi- to endocardial differences in the patterns of expression of both Kv4.2 and KChIP2.

Biological activities of a recombinant adenovirus p53 (SCH 58500) administered by hepatic arterial infusion in a Phase 1 colorectal cancer trial

The major focus of intrahepatic arterial (IHA) administration of adenoviruses (Ad) has been on safety. Currently, there is little published data on the biological responses to Ad when administered via this route. As part of a Phase I study, we evaluated biological responses to a replication-defective adenovirus encoding the p53 transgene (SCH 58500) when administered by hepatic arterial infusion to patients with primarily colorectal cancer metastatic to the liver. In analyzing biological responses to the Ad vector, we found that both total and neutralizing Ad antibodies increased weeks after SCH 58500 infusion. The fold increase in antibody titers was not dependent on SCH 58500 dosage. The proinflammatory cytokine interleukin-6 (IL-6) transiently peaked within 6 h of dosing. The cytokine sTNF-R2 showed elevation by 24 h post-treatment, and fold increases were directly related to SCH 58500 doses. Cytokines TNF-alpha, IL-1beta, and sTNF-R1 showed no increased levels over 24 h. Predose antibody levels did not appear to predict transduction, nor did serum Ad neutralizing factor (SNF). Delivery of SCH 58500 to tumor tissue occurred, though we found distribution more predominantly in liver tissues, as opposed to tumors. RT-PCR showed significantly higher expression levels (P<0.0001, ANOVA) for adenovirus type 2 and 5 receptor (CAR) in liver tissues, suggesting a correlation with transduction. Evidence of tumor-specific apoptotic activity was provided by laser scanning cytometry, which determined a coincidence of elevated nuclear p53 protein expression with apoptosis in patient tissue. IHA administration of a replication defective adenovirus is a feasible mode of delivery, allowing for exogenous transfer of the p53 gene into target tissues, with evidence of functional p53. Limited and transient inflammatory responses to the drug occurred, but pre-existing immunity to Ad did not preclude SCH 58500 delivery.

Assessment of reprocessed arthroscopic shaver blades

PURPOSE

The purpose of this study was to evaluate the level of contaminants on, as well as the quality of, reprocessed shaver blades.

METHODS

We assessed 7 new shaver blades and 27 shaver blades that had been reprocessed with mechanical cleaning, functional testing, and sterilization with ethylene oxide. A spectrophotometer measured the amount of nucleic acid and protein. The blade quality was assessed by photographing the blades with magnification and determining the percentage of damage present on each blade. A subset of shaver blades were then used to cut meniscal tissue, and the cut surface was measured for smoothness by image processing and automated laser scanning cytometry. In evaluation of the meniscus, for the subset of shavers, an image processing value of 1 indicates a smooth, straight line, and values lower than 1 reflect deviations in the cut surface (the closer the value is to 1, the smoother the surface). Laser scanning cytometry values indicate the percentage of irregularities in the cut surface (the lower the value is, the smoother the surface).

RESULTS

Of the 27 reprocessed shaver blades, 13 (48%) had detectable levels of protein and 17 (63%) had detectable levels of nucleic acid. On the reprocessed shaver blades, protein levels ranged from 2.43 microg to 60 microg and nucleic acid levels ranged from 0.40 microg to 3.5 microg. No new shaver blade had contaminants. Twenty reprocessed shaver blades had been manufactured with teeth and could be evaluated for visible damage. Of these, 10 had 1% to 25% damage, 5 had 26% to 50% damage, 3 had 51% to 75% damage, and 2 had 76% to 100% damage. The new blades had no visible damage. Image processing revealed smoothness of the surface cut with new shaver blades, yielding values of 1 +/- 0.12, whereas the values for reprocessed shaver blades ranged from 0.62 +/- 0.02 to 1 +/- 0.07. Laser scanning cytometry values ranged from 3.3% to 7.1% for the new blades as compared with 5.8% to 20.0% for the reprocessed blades.

CONCLUSIONS

Of the reprocessed shaver blades, 48% had detectable levels of protein and 63% had detectable levels of nucleic acid. All of the reprocessed blades visually evaluated showed some level of damage or wear, whereas no new blade had such damage. In addition, menisci cut with reprocessed shavers showed rougher edges than did menisci cut with new shavers.

CLINICAL RELEVANCE

To make an informed decision regarding the use of reprocessed shaver blades, surgeons will want to know the level of contamination on, and the quality of, reprocessed shaver blades.

Role of ancillary techniques in diagnosing and subclassifying non-Hodgkin's lymphomas on fine needle aspiration cytology

Non-Hodgkin's lymphomas (NHL) are tumours of the lymphoid cells. During the process of development of lymphoid cells, neoplasia may evolve at any point. Neoplastic cells usually carry the imprint of cell of origin at the stage of origin. Various types of NHL may have similar morphology with wide variation in origin, immunophenotype and other biological features. Different ancillary laboratory techniques may help to overcome the limitations of morphology in this aspect. The commonly used ancillary techniques in lymphomas are immunocytochemistry (IC), flow cytometry, Southern blot (SB) technique, polymerase chain reaction (PCR) and fluorescent in situ hybridization (FISH). In addition, laser scanning cytometry (LSC) and DNA microarray technologies are in the research phase. Various laboratory techniques are used for immunophenotyping, demonstration of monoclonality, identification of chromosomal translocation, assessment of cell kinetics and expression of mRNA in the tumour cells. Flow cytometry helps in rapid immunophenotying of NHL and it has an added advantage over IC in recognizing the co-expression of CD markers. Fine needle aspiration cytology (FNAC) combined with flow immunophenotyping may help us to diagnose and subclassify certain NHLs, such as follicular lymphoma and mantle cell lymphoma, which were previously recognized as pure morphological entities. Loss of morphology is one of the important limitations of flow cytometry. LSC can overcome this limitation by studying morphology along with the immunophenotyping pattern of individual cells. Chromosomal changes in NHL can be identified by SB, PCR and FISH. Molecular diagnosis of NHL helps in diagnosis, subclassification, prognostic assessment and even in planning of therapy. DNA microarray is a relatively newer and promising technology. It gives information about the expression of several thousands of genes in a tumour in a single experiment. In the near future, FNAC combined with ancillary techniques may play a major role in diagnosis, subclassification and management of lymphomas.

Biomarker analysis on breast ductal lavage cells in women with and without breast cancer

Recent studies show that morphology based analysis of ductal lavage specimens failed to detect many cancers in women with breast cancer. Such an observation raises doubts about the potential role of ductal lavage in an individual's risk assessment and early detection of breast cancer. We hypothesize that biomarker-based analysis using markers of malignancy field defects including DNA 5c exceeding rate (DNA 5cER) and G-actin might provide a more reliable test for breast cancer risk. The study was performed in 2 phases, the training and validation phase. For the training phase, 36 Chinese women were recruited (13 with breast cancer, 8 with intraductal papilloma and 15 with benign breast diseases). The validation phase included 10 women with cancer and 7 women without cancer. Ductal lavage samples were processed by the ThinPrep technique and evaluated by morphology followed by biomarker analysis using laser scan cytometry (LSC) for G-actin and DNA5cER. In the training phase, biomarker analysis was performed on the 67% (24 of 36) of samples that had over 100 epithelial cells. The sensitivity of DNA5cER was 90% with a specificity of 100%, and G-actin was 100% and 93%, respectively. By contrast, the sensitivity and specificity obtained by cytology alone were 67% and 93%, respectively. Similar results were obtained from the small validation study. Quantitative analysis of biomarkers for G-actin and DNA5cER is feasible and useful in distinguishing benign from malignant breast disease on archived ductal lavage slides. Further studies are warranted to determine the value of these biomarkers in prospective trials.

Overexpression of polo-like kinase 1 (PLK1) and chromosomal instability in bladder cancer

Polo-like kinase 1 (PLK1) participates in bipolar spindle formation and entry into mitosis. Chromosomal instability (CIN) is caused by abnormalities in spindle formation and chromosome segregation. In this study, we investigated the relationship of PLK1 overexpression to CIN, and compared the PLK1 status with clinicopathological parameters in 101 human urothelial carcinomas of the urinary bladder. Expression of PLK1 and the number of centrosomes were assessed by immunohistochemistry. Numerical aberrations of chromosomes 7, 9 and 17 spots that allowed estimation of CIN were evaluated by fluorescence in situ hybridization, and DNA ploidy was assessed by laser scanning cytometry. Cancers with a large intercellular variation in centromere copy number were defined as CIN cancers. Tumors with PLK1 overexpression were associated more frequently with CIN (p < 0.0001), DNA aneuploidy (p = 0.0007) and centrosome amplification (p = 0.0013) than those without. Overexpression of PLK1 was significantly related to higher pathological grade (p = 0.0024), multiple tumors (p = 0.0241) and positive urine cytology (p = 0.0192). These data suggest that a high level expression of PLK1 confers tumor progression advantages to urothelial cancer cells, although other factors are also involved.

Tolfenamic acid and pancreatic cancer growth, angiogenesis, and Sp protein degradation

BACKGROUND

Sp1, Sp3, and Sp4 are transcription factors that regulate cell proliferation and vascular endothelial growth factor (VEGF) expression and are overexpressed in many cancer cell lines. For some cancers, Sp1 overexpression is associated with poor survival. Cyclooxygenase inhibitors decrease Sp1 expression in cancer cells, and therefore different structural classes of nonsteroidal anti-inflammatory drugs (NSAIDs) were screened for their ability to decrease levels of Sp1, Sp3, and Sp4 and to decrease pancreatic tumor growth and metastasis in an in vivo model.

METHODS

Levels of Sp1, Sp3, Sp4, and VEGF proteins in pancreatic cancer cell lines were assessed by immunoblot analysis. mRNA was assessed by reverse transcription-polymerase chain reaction. Panc-1 pancreatic cancer cells transfected with VEGF promoter constructs were used to assess VEGF promoter activation. Pancreatic tumor weight and size and liver metastasis were assessed in an orthotopic mouse model of pancreatic cancer (groups of 10 mice). Protein expression in tumors was assessed immunohistochemically.

RESULTS

Tolfenamic acid and structurally related biaryl derivatives induced degradation of Sp1, Sp3, and Sp4 in pancreatic cancer cells. Tolfenamic acid also inhibited VEGF mRNA and protein expression in pancreatic cancer cells; this inhibition was associated with the decreased Sp-dependent activation of the VEGF promoter. In the mouse model for pancreatic cancer, treatment with tolfenamic acid (50 mg/kg of body weight), compared with control treatment, statistically significantly decreased tumor growth and weight (P = .005), liver metastasis (P = .027), and levels of Sp3 and VEGF (P = .009) and Sp1 and Sp4 (P = .006) proteins in tumors. For example, tumors from mice treated with tolfenamic acid (50 mg/kg) had statistically significantly lower VEGF levels (45%, 95% confidence interval = 39% to 51%; P = .009) than tumors from control mice.

CONCLUSIONS

Tolfenamic acid is a new antipancreatic cancer NSAID that activates degradation of transcription factors Sp1, Sp3, and Sp4; reduces VEGF expression; and decreases tumor growth and metastasis.

Controversy fuels trafficking of GPI-anchored proteins

The model that glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) take a direct transport route to the apical membrane of epithelial cells has recently been challenged. In this issue, Paladino et al. (p. 1023) and Hua et al. (p. 1035) show that the original view nevertheless holds. This closes a chapter in the winding story of GPI-AP trafficking but opens another phase, as the controversy has stimulated the development of new methodology.

Laser scanning cytometer-based assays for measuring host cell attachment and invasion by the human pathogen Toxoplasma gondii

BACKGROUND

Toxoplasma gondii is among the most common protozoan parasites of humans. Both attachment to and invasion of host cells by T. gondii are necessary for infection, yet little is known about the molecular mechanisms underlying these processes. T. gondii's etiological importance and its role as a model organism for studying invasion in related parasites necessitate a means to quantitatively assay host cell attachment and invasion.

METHODS

We present here Laser Scanning Cytometer (LSC)-based assays of T. gondii invasion and attachment. The invasion assay involves automated counting of invaded and non-invaded parasites, differentially labeled with distinct fluorochromes. The attachment assay compares the relative binding of differentially labeled parasites. The assays were evaluated using treatments known to decrease invasion or attachment.

RESULTS

The LSC-based assays are robust and reproducible, remove operator bias, and significantly increase the sample size that can be feasibly counted compared to other currently available microscope-based methods. In the first application of the new assays, we have shown that parasites attach to fixed and unfixed host cells using different mechanisms.

CONCLUSIONS

The LSC-based assays represent useful new methods for quantitatively measuring attachment and invasion by T. gondii, and can be readily adapted to study similar processes in other host-pathogen systems.

In vivo imaging with cellular resolution of bone marrow cells transplanted into the ischemic brain of a mouse

The aim of the study was to monitor in vivo and noninvasively the fate of single bone marrow cells (BMCs) transplanted into the ischemic brain of unirradiated mice. In vivo imaging was performed through a closed cranial window, throughout the 2 weeks following cell transplantation, using laser-scanning confocal fluorescence microscopy. The window was chronically implanted above the left parieto-occipital cortex in C57BL/6J adult mice. BMC (3 x 10(5) nucleated cells in 0.5 microL medium) from 5-week-old transgenic mice, ubiquitously expressing green fluorescent protein (GFP), was transplanted into the ipsilateral cortex 24 h after the induction of focal ischemia by coagulation of the left middle cerebral artery (n = 15). Three nonischemic mice served as controls. Repeated in vivo imaging, up to a depth of 200 microm, revealed that BMCs survived within the ischemic and peri-ischemic cortex, migrated significantly towards the lesion, proliferated and adopted a microglia-like morphology over 2 weeks. These results were confirmed using ex vivo imaging after appropriate immunocytochemical treatments. This study indicates that confocal fluorescence microscopy is a reliable and unique tool to repeatedly assess with cellular resolution the in vivo dynamic fate of fluorescent cells transplanted into a mouse brain. These results also provide the first in vivo findings on the fate of single BMCs transplanted into the ischemic brain of unirradiated mice.

Distinct patterns of MCM protein binding in nuclei of S phase and rereplicating SV40-infected monkey kidney cells

BACKGROUND

Simian Virus 40 (SV40) infection of growth-arrested monkey kidney cells stimulates S phase entry and the continued synthesis of both viral and cellular DNA. Infected cells can attain total DNA contents as high as DNA Index, DI = 5.0-6.0 (10-12C), with host cell DNA representing 70-80% of the total. In this study, SV40-infected and uninfected control cells were compared to determine whether continued DNA replication beyond DI = 2.0 was associated with rebinding of the minichromosome maintenance (MCM) hexamer, the putative replicative helicase, to chromatin.

METHOD

Laser scanning cytometry was used to measure the total expression per cell and the chromatin/matrix-association of two MCM subunits in relation to DNA content.

RESULTS

MCM2 and MCM3 proteins that were associated with the chromatin/matrix fraction in G1 phase of both uninfected and SV40-infected cells were gradually released during progression through S phase. However, in SV40-infected cells that progressed beyond DI = 2.0, chromatin/matrix-associated MCM2 and MCM3 remained at the low levels observed at the end of S phase. Rereplication was not preceded by an obvious rebinding of MCM proteins to chromatin, as was observed in G1 phase.

CONCLUSIONS

The rereplication of host cell DNA in the absence of the reassociation of MCM proteins with chromatin indicates that SV40 infection induces a novel mechanism of licensing cellular DNA replication.

Analysis of hypoxia-inducible factor-1alpha accumulation and cell cycle in geldanamycin-treated human cervical carcinoma cells by laser scanning cytometry

BACKGROUND

Tumor hypoxia has been linked to increased disease aggressiveness and poorer treatment outcomes, and the transcription factor hypoxia-inducible factor-1 (HIF-1) has been identified as the key molecule mediating the cellular response to hypoxic microenvironments. The alpha-subunit of this factor is accumulated under hypoxia and rapidly degraded during re-oxygenation, rendering the reliable measurement of HIF-1alpha a difficult task. Heat shock protein 90 (Hsp90) is an essential protein that controls the activity, turnover, and trafficking of a variety of other proteins including HIF-1alpha and cell cycle regulators. Hsp90 inhibitors like geldanamycin therefore have the potential to target tumor-cell survival by at least two mechanisms, compromising the accumulation of HIF-1alpha and cell proliferation.

METHODS

We describe here the simultaneous measurement of HIF-1alpha and cell cycle parameters by laser scanning cytometry (LSC) after exposure of two different human cervical carcinoma cell lines to hypoxia and geldanamycin.

RESULTS

Our analysis demonstrates that the cell lines react to hypoxia and drug treatment in a distinct way, with SiHa being more affected by low oxygen concentrations than is ME180, which was more sensitive to geldanamycin treatment. Both cell lines respond to geldanamycin with a G(2)/M-phase arrest and a decrease in HIF-1alpha accumulation. Cell death due to geldanamycin occurs in association with mitosis, presumably through mitotic catastrophe.

CONCLUSION

Our results indicate that LSC can significantly contribute to the evaluation of in vitro drug effects particularly with respect to tumor hypoxia and the measurement of HIF-1alpha.

Global genomic changes induced by two-stage carcinogen exposure are precancerous alterations in non-transformed human liver epithelial THLE-3 cells

Global genomic changes, including DNA aneuploidy, may be necessary for carcinogenesis; however, such genomic changes in precancerous cells have not been studied extensively. To identify early global genotypic changes associated with precancerous lesions, a non-transformed human liver epithelial cell line, THLE-3, was treated with benzo[a]pyrene or N-methyl-N-nitro-N-nitrosoguanidine, then by 12-O-tetradecanoyl-phorbol-13-acetate, resulting in morphological transformation of cells. We examined genotypic changes of the transformed cells by laser scanning cytometry, fluorescence in situ hybridization, and comparative genomic hybridization. Transformed fusiform cells displayed tetraploidy, chromosomal instability, DNA copy number aberrations. Cells with these changes were still in the precancerous stage. However, it is suggested that these global genomic changes including tetraploidization provide cells with genetic alterations leading to cancer.

[Expression and intranuclear distribution of nucleolin in estrogen receptor-negative and estrogen receptor-positive breast cancers in women measured by laser scanning cytometry]

INTRODUCTION

Nucleolin (NU) is one of the most abundant nucleolar proteins. Nucleolin is mainly involved in ribosome biogenesis that is supported by the ability of NU to bind rDNA and modify the structure of chromatin by binding to histon H1. Estrogen receptor alpha (ERalpha) is a DNA-binding transcriptional factor. It is estimated that 69-85% of breast cancers in women are ERalpha-positive. The aim of the study was to assess the expression and intranuclear distribution of NU in invasive ductal and lobular breast cancers in women and their relationship to ERalpha-status, histologic type and grade of breast cancer, and lymph node status. For this purpose, laser scanning cytometry (LSC) was used.

MATERIAL AND METHODS

Measurements were done in cytospins of cancer cells of 87 ductal and 11 lobular invasive breast cancers. The cells were labeled with mouse anti-human NU antibody followed by F(ab')2 fragments of FITC-conjugated goat anti-mouse antibody. Nuclei were counterstained with 5 microg/mL of propidium iodide in the presence of 100 microg/mL of RNase A. All measurements were performed using LSC. The following parameters of individual cancer cells were calculated: NU fluorescence within the nucleus, within nucleolin aggregates (NUA) and in the remaining karyoplasm, number of NUA, area of the nucleus and NUA. The percentage of ER-positive breast cancer cells was calculated in parallel by the automated image analysis in formalin-fixed sections using immunohistochemistry with anti-ERalpha antibody. The cut-off value for ER-negative tumors was set at 10% of positively stained nuclei. Statistical analysis was done using the Statistica 5.0 software. P values less than 0.05 were considered statistically significant.

RESULTS

The mean area of the nucleus of ductal cancer cells was significantly higher and NU expression lower in ERalpha-negative cancers than in ERalpha-positive ones (p = 0.007 and p = 0.04, respectively). The mean area of NUA and NU expression in ductal cancers were higher than in lobular cancers (p = 0.03 and p = 0.02, respectively). The expression of NU within the nucleus and within the karyoplasm besides NUA was significantly higher in ductal than in lobular cancers (p = 0.02 and p = 0.04, respectively). The expression of NU in the remaining karioplasm of tumor cells of lymph node-positive cancers was lower than in node-negative ones (p = 0.04). The same relation was found for ductal cancers (p = 0.02).

CONCLUSIONS

The differences in nucleolin expression and its intranuclear distribution in ERalpha-negative and ERalpha-positive breast cancers, as well as ductal and lobular cancers point to biologic differences between these carcinomas. The method used in the study may be applied to measurements of expression and intranuclear distribution of other nuclear proteins or to simultaneous measurement of expression and distribution of nuclear and cytoplasmic proteins.