Human Esophagus Research Articles

A series of poly[N‐(2‐hydroxypropyl)methacrylamide] copolymers with anthracene‐derived fluorophores showing aggregation‐induced emission properties for bioimaging

A series of new poly[N-(2-hydroxypropyl)methacrylamide]-based amphiphilic copolymers were synthesized through a radical copolymerization of a monomeric/hydrophobic fluorophore possessing aggregation-induced emission (AIE) property with N-(2-hydroxypropyl)methacrylamide. Photophysical properties were investigated using UV-Vis absorbance and fluorescence spectrophotometry. Influences of the polymer structures with different molar ratios of the AIE fluorophores on their photophysical properties were studied. Results show that the AIE fluorophores aggregate in the cores of the micelles formed from the amphiphilic random copolymers and polymers with more hydrophobic AIE fluorophores facilitate stronger aggregations of the AIE segments to obtain higher quantum efficiencies. The polymers reported herein have good water solubility, enabling the application of hydrophobic AIE materials in biological conditions. The polymers were endocytosed by two experimental cell lines, human brain glioblastoma U87MG cells and human esophagus premalignant CP-A, with a distribution into the cytoplasm. The polymers are non-cytotoxic to the two cell lines at a polymer concentration of 1 mg/mL.

Depth-resolved monitoring of diffusion of hyperosmotic agents in normal and malignant human esophagus tissues using optical coherence tomography in-vitro

Depth-resolved monitoring with differentiation and quantification of glucose diffusion in healthy and abnormal esophagus tissues has been studied in vitro. Experiments have been performedusing human normal esophagus and esophageal squamous cell carcinoma (ESCC) tissues by the optical coherence tomography (OCT). The images have been continuously acquired for 120 min in theexperiments, and the depth-resolved and average permeability coefficients of the 40 % glucose solution have been calculated by the OCT amplitude (OCTA) method. We demonstrate the capabilityof the OCT technique for depth-resolved monitoring, differentiation, and quantifying of glucose diffusion in normal esophagus and ESCC tissues. It is found that the permeability coefficients of the 40 % glucose solution are not uniform throughout the normal esophagus and ESCC tissues and increase from (3.30 ± 0.09) × 10-6 and (1.57 ± 0.05) × 10-5 cm s-1 at the mucous membrane of normal esophagus and ESCC tissues to (1.82 ± 0.04) × 10-5 and (3.53 ± 0.09) × 10-5 cm s-1 at the submucous layer approximately 742 μm away from the epithelial surface of normal esophagus and ESCC tissues, respectively.

Proteomic analysis of gene expression during human esophagus cancer

Esophagus cancer is the eighth most common cancer worldwide and particularly high in an area extending from the southern border of the Caspian Sea in Iran across central Asia to China. Since information about this mysterious disease is poor, proteomics may be solving this enigma. Altering gene expression in cancer cell is a remarkable indicator can be detected by proteomics techniques and bioinformatic analysis. In this study, normal and cancerous cells were obtain from patients, total proteins were purified by standard methods, and proteins separated by two dimensional electrophoresis (2DE). Some of proteins were identified by Mass spectrometry (MS-MALDI method). By using bioinformatic analysis illustrate molecular mechanism in this disease. Analysis of gels base on Flicker software and Mass Spectrometry led the same result. 61 protein spots detected in both gels that 21 spots have down regulated and 12 spots have up regulated in cancerous cell than normal. About 14 spots were disappeared in cancer cell while 14 new spots expressed. By using flicker detected 8 Protein that refer to TRFE, SZ07, C1 TC, Kininogen, anexin, keratin, fructosebisphosphate aldolase A and heat shock. Mass spectrometry (MS-MALDI method) identified anexin, keratin, fructosebisphosphate aldolase A and heat shock. Identified proteins were functionally categorized based on Gene Ontology (GO) annotation terms using the DAVID program package. The major molecular functions that annotated with PIR include phosphoprotein, disease mutation while annotated by GO include response to organic substance, response to wounding and cellular homeostasis. The cellular component and molecular function presenting the greatest enrichment that concluded two clusters that the two most importants are cellular homeostasis and extracellular region part. Results reveal that the most of molecular function in cancerous tissue maintenance cellular homeostasis, cell regeneration and repair, so tissues undergo stress try to survive. It can be also concluded that aldolase A, fructose-bisphosphate, keratin 14, formyltetrahydrofolate synthetase and transferrin can be some diagnostic biomarkers and also drug targets in esophagus cancer.

Triazacryptand-based fluorescent sensors for extracellular and intracellular K + sensing

A 4-amino-naphthalimide derived fluorophore with a triazacryptand moiety ligand was synthesized as a potassium ion (K +) sensor (KS1). This sensor is a monomer possessing a polymerizable vinyl group. By taking advantage of the polymerizable characteristics of the vinyl group, KS1 was polymerized with 2-hydroxyethyl methacrylate (HEMA) and acrylamide (AM) to form K + sensing films for extracellular sensing. The sensitivity of the films to potassium ions can be further tuned through the adjustment of the HEMA and AM weight ratios as well as introduction of positive or negative charge-containing segments. KS1 and its poly(2-hydroxyethyl methacrylate)- co-poly(acrylamide) (PHEMA- co-PAM) thin films show high selectivity for K + over competing sodium ions (Na +) at physiological concentrations. Extracellular sensing was demonstrated using a KS1-conjugated PHEMA- co-PAM thin film to measure the K + efflux of Escherichia coli ( E. coli) and Bacillus subtilis ( B. subtilis) stimulated by lysozyme. Meanwhile, KS1 itself permeates human glioblastoma U87MG and human esophagus premalignant CP-A cell lines. KS1 was used to monitor K + efflux stimulated by adenosine-5′-triphosphate (ATP), amphotericin, and a mixture of nigericin, bumetanide and ouabain, demonstrating application of this material as an intracellular potassium ion sensor.

P73 protein regulates DNA damage repair

Although the p53 tumor suppressor is relatively well characterized, much less is known about the functions of other members of the p53 family, p73 and p63. Here, we present evidence that in specific pathological conditions caused by exposure of normal cells to bile acids in acidic conditions, p73 protein plays the predominant role in the DNA damage response. These pathological conditions frequently occur during gastric reflux in the human esophagus and are associated with progression to esophageal adenocarcinoma. We found that despite strong DNA damage induced by bile acid exposure, only p73 (but not p53 and p63) is selectively activated in a c-Abl kinase-dependent manner. The activated p73 protein induces DNA damage repair. Using a human DNA repair PCR array, we identified multiple DNA repair genes affected by p73. Two glycosylases involved in base excision repair, SMUG1 and MUTYH, were characterized and found to be transcriptionally regulated by p73 in DNA damage conditions. Using a surgical procedure in mice, which recapitulates bile acid exposure, we found that p73 deficiency is associated with increased DNA damage. These findings were further investigated with organotypic and traditional cell cultures. Collectively our studies demonstrate that p73 plays an important role in the regulation of DNA damage repair.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Berberine Radiosensitizes Human Esophageal Cancer Cells by Downregulating Homologous Recombination Repair Protein RAD51

BackgroundEsophageal squamous cell carcinomas (ESCC) have poor prognosis. While combined modality of chemotherapy and radiotherapy increases survival, most patients die within five years. Development of agents that confer cancer cell-specific chemo- and radiosensitivity may improve the therapy of ESCC. We here reported the discovery of berberine as a potent radiosensitizing agent on ESCC cells.Principal FindingsBerberine at low concentrations (<15 µM) substantially radiosensitized ESCC cells. X-ray induced DNA double-strand breaks (DSBs) persist longer in ESCC cells pretreated with berberine. Berberine pretreatment led to a significant downregulation of RAD51, a key player in homologous recombination repair, in ESCC cells, but not in non-malignant human cells. Downregulation of RAD51 by RNA interference similarly radiosensitized the cancer cells, and, conversely, introduction of exogenous RAD51 was able to significantly counteract the radiosensitizing effect of berberine, thus establishing RAD51 as a key determinant in radiation sensitivity. We also observed that RAD51 was commonly overexpressed in human ESCC tissues, suggesting that it is necessary to downregulate RAD51 to achieve high radio- or chemotherapeutic efficacy of ESCC in clinic, because overexpression of RAD51 is known to confer radio- and chemoresistance.Conclusions/SignificanceBerberine can effectively downregulate RAD51 in conferring radiosensitivity on esophageal cancer cells. Its clinical application as an adjuvant in chemotherapy and radiotherapy of esophageal cancers should be explored.

Can the rat be used as a valid model of human esophageal adenocarcinoma?

Animal models of Barrett's metaplasia and esophageal adenocarcinoma are important to further characterize the disease and test potential therapies. This paper reviews the development of the surgical model of esophageal adenocarcinoma in the rat and considers whether this model provides a biologically accurate representation of Barrett's esophagus and esophageal adenocarcinoma in humans.

Fuzzy Rule based Classification of Microscopic Images of Squamous Cell Carcinoma of Esophagus

paper, we present a novel method based on active contours for segmentation and fuzzy rule based classification of microscopic images of esophagus tissues obtained from the abnormal regions of human esophagus detected through endoscopy. This method is used for classification of Squamous Cell Carcinoma (SCC) of esophagus, namely, well differentiated (WD), moderately differentiated (MD), and poorly differentiated (PD) SCC. The multi-grid active contour method is used for cell nuclei segmentation, three geometric features are used feature extraction and a fuzzy rule based classifier is built for classification of SCC. The experimental results demonstrate the efficacy of the proposed method. Keywordsmicroscopic image, squamous cell carcinoma, geometric features, active contour segmentation

TRiPping down the oesophagus

TRiPping down the oesophagus

Antioxidant and antiproliferative activities of heated sterilized pepsin hydrolysate derived from half-fin anchovy (Setipinna taty).

In this paper we studied the antioxidant and antiproliferative activities of the heated pepsin hydrolysate from a marine fish half-fin anchovy (HAHp-H). Furthermore, we compared the chemical profiles including the amino acid composition, the browning intensity, the IR and UV-visible spectra, and the molecular weight distribution between the half-fin anchovy pepsin hydrolysate (HAHp) and HAHp-H. Results showed that heat sterilization on HAHp improved the 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical-scavenging activity and reducing power. In addition, the antiproliferative activities were all increased for HAHp-H on DU-145 human prostate cancer cell line, 1299 human lung cancer cell line and 109 human esophagus cancer cell line. The contents of free amino acid and reducing sugar of HAHp-H were decreased (P < 0.05). However, hydrophobic amino acid residues and the browning intensity of HAHp-H were increased. FT-IR spectroscopy indicated that amide I and amide III bands of HAHp-H were slightly modified, whereas band intensity of amide II was reduced dramatically. Thermal sterilization resulted in the increased fractions of HAHp-H with molecular weight of 3000–5000 Da and below 500 Da. The enhanced antioxidant and antiproliferative activities of HAHp-H might be attributed to the Maillard reaction.

Enhancement of Cytotoxicity against IL-15 Up-regulate NKG2D Expression on Cytokine-induced Killer Cells

Objective To analyse the effects of IL-15 on the expression of NKG2D and the cytotoxicity of cytokine-induced killer(CIK) cells against human esophagus carcinoma cell EC9706 in vitro.Methods Peripheral blood mononuclear cells were isolated from healthy donors then divided into two groups: the control group(cells were cultured in the presence of IFN-γ,anti-CD3 antibody and IL-2) and IL-15 group(cells were cultured in the presence of IFN-γ,anti-CD3 antibody,IL-2 and 10 ng/ml IL-15).Phenotypic characteristics of CIK cells and the expression of NKG2D were analyzed by flow cytometry.After 14 days culture,cytotoxicity of CIK cells against EC9706 cells was measured by using a standard LDH releasing assay.Effector cells were added to target cells at E∶T radios of 20∶1,30∶1.In blocking experiments,NKG2D monoclonal antibody was added to CIK cells for 15 min before plating at 30∶1 E∶T ratio.Results NKG2D molecules were significantly up-regulated during the culture period on CD3+ cells(the CIK cells population) and the CD56+cells.The differences of NKG2D expressions were significant between IL-15 group and the control group(P0.05).Cytotoxicity of CIK cells treated by the IL-15 group was higher than that of the control group,both at 20∶1 E∶T ratios and at 30∶1 E∶T ratios(P0.05).When the NKG2D molecules on CIK cell ular membrance were blocked by the NKG2D monoclonal antibody,the cytolytic activity in the control group cells and IL-15 group cells was significantly inhibited.Conclusion IL-15 up-regulated the expression of NKG2D on CIK cells,which enhanced the NKG2D mediated cytotoxicity against EC9706 cells.CIK cells played a role through the NKG2D molecules.

Morphology of the developing muscularis externa in the mouse esophagus

Muscularis externa of mouse esophagus is composed of two skeletal muscle layers in the adult. But less attention is paid to the histogenesis of the muscularis externa of the esophagus, and controversies still exist about the developmental process and the spatio-temporal expression characteristics of muscle-specific proteins during the development of esophageal muscularis externa. To further probe into the developmental pattern of muscularis externa of the mouse esophagus and the expression characteristics of different muscle-specific proteins, immunohistochemical and terminal deoxyribonucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP)-digoxigenin nick-end labeling apoptotic staining methods are used to investigate the expression patterns of different muscle-specific proteins and to elucidate the relationship of these protein expressions with the development of muscularis externa of the mouse esophagus. Thus, an understanding of the developing esophageal muscularis externa may be important for developing therapeutic strategies for the treatment of human esophagus diseases. Serial sections of mouse embryos from embryonic day (ED) 12 to ED18, and full-length esophagi from postnatal first to 5th day were stained with monoclonal antibodies against α-smooth muscle actin (α-SMA), α-sarcomerical actin (α-SCA), desmin, and monoclonal anti-skeletal myosin (MHC), while apoptosis was determined using the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labeling assay. The expression of α-SMA was started at ED12. During the development of ED14-ED15, α-SMA positive cells were seen extending from the walls of left three, four, and six arch arteries toward the dorsal wall of esophagus. Stronger expression of α-SCA and desmin could be detected at ED14 and ED15, expression intensity in caudal segment and inner layer was stained stronger than that of cranial segment and outer layer, but after ED16, strong expression of α-SCA and desmin was found in the outer layer of muscularis externa. Expression of MHC was first detected in the outer layer of cranial segment of muscularis externa at ED17. At ED18, MHC had extended to the level of thyroid gland, staining intensity in the outer layer and cranial segment was stronger than that of inner layer and caudal segment. One to five days after birth, the thickness of the esophageal muscle layer was obviously increased. Most of the muscle cells in the cranial segment of esophagus showed strong expression of α-SCA and clear cross striations at higher magnification. With progression toward the caudal segment, expression intensity of α-SCA became weaker, but the expression intensity of desmin was the same at different levels of esophagus. The muscle fibers were arranged densely with high expression of MHC in the cranial segment. During the development of esophageal muscularis externa, few apoptotic cells were observed. α-SMA, α-SCA, desmin, and MHC show different expression patterns. The differentiation of outer layer of esophageal muscularis externa is quicker than that of inner layer, and the caudal segment is quicker than that of the cranial segment. Besides, apoptosis may not participate in the development of esophageal muscularis externa. The smooth muscle cells from arch arteries may participate in the development of esophageal muscularis externa.

Comprehensive volumetric confocal microscopy with adaptive focusing

Comprehensive microscopy of distal esophagus could greatly improve the screening and surveillance of esophageal diseases such as Barrett’s esophagus by providing histomorphologic information over the entire region at risk. Spectrally encoded confocal microscopy (SECM) is a high-speed reflectance confocal microscopy technology that can be configured to image the entire distal esophagus by helically scanning the beam using optics within a balloon-centering probe. It is challenging to image the human esophagus in vivo with balloon-based SECM, however, because patient motion and anatomic tissue surface irregularities decenter the optics, making it difficult to keep the focus at a predetermined location within the tissue as the beam is scanned. In this paper, we present a SECM probe equipped with an adaptive focusing mechanism that can compensate for tissue surface irregularity and dynamic focal variation. A tilted arrangement of the objective lens is employed in the SECM probe to provide feedback signals to an adaptive focusing mechanism. The tilted configuration also allows the probe to obtain reflectance confocal data from multiple depth levels, enabling the acquisition of three-dimensional volumetric data during a single scan of the probe. A tissue phantom with a surface area of 12.6 cm2 was imaged using the new SECM probe, and 8 large-area reflectance confocal microscopy images were acquired over the depth range of 56 μm in 20 minutes. Large-area SECM images of excised swine small intestine tissue were also acquired, enabling the visualization of villous architecture, epithelium, and lamina propria. The adaptive focusing mechanism was demonstrated to enable acquisition of in-focus images even when the probe was not centered and the tissue surface was irregular.

Three-Dimensional Optical Coherence Tomography on Endoscopic Mucosal Resection Specimens Confirms Identification of Malignant From Metaplastic Lesions in Patients With Barrett's Esophagus

BACKGROUND/AIMS: Endoscopic mucosal resection (EMR) has been an effective method to assess patients with esophageal nodules arising in Barrett's esophagus (BE). Optical Coherence Tomography (OCT) enables real-time, three-dimensional (3D) imaging of tissue microstructure, with resolution approaching histology and can be used to evaluate pathological features both In Vivo and within EMR specimens. In comparison, the latter is difficult to assess on confocal endoscopy which depends on In Vivo fluorescein to achieve optimal images . METHODS: A prototype OCT imaging system was developed in collaboration with the LightLab imaging Inc., providing images with an axial resolution of ~5um in tissue and ~15um along the transverse dimension. The OCT system has an axial scanning rate of ~59kHz and the system sensitivity is 103dB. The in-house developed fiberoptic imaging probe (2.5mm in diameter) can pass through the working channel of the endoscope. A 3DOCT dataset covering an imaging area of 20 mm x 8 mm x 2 mm can be acquired in 20s. Standard EMR was performed on 12 patients using Duette (Cook Medical, Inc.). Twentyfour EMR specimens, including 9 benign, 6 BE, 2 BE with low-grade dysplasia, 1 BE with high grade dysplasia, and 6 early adenocarcinomas, were subsequently imaged with 3DOCT and sent for standard H&E histology. Imaging features identified in the OCT images were then compared with matching histology. RESULTS: Cross-sectional and en face images could be reconstructed from the 3D-OCT dataset. Cross-sectional OCT image showed features matching with the corresponding histology. BE glands were observed at regions over the lamina propria layer while both the lamina propria layer and the muscular mucosa were preserved in 87% of OCT imaging dataset. En face OCT highlighted the distribution of the glandular structures in Barrett's esophagus and allowed quantification of BE gland density. In lesions with intramucosal and invasive adenocarcinoma, the muscular mucosa layer was less distinct or lost in the OCT images. This may be due to the destruction of tissue architecture or the thickened mucosa from the tumor. No lamina propria layer is identified in the datasets of 6 early adenocarcinomas. In addition, the shape and the distribution of the glandular structures were irregular compared to those of the BE glands. These distinctive patterns associated with adenocarcinoma were observed in both cross-sectional and en face OCT images. CONCLUSIONS: We demonstrated 3D-OCT images of EMR specimens of human esophagus ranging from benign nodules, BE with LGD, BE with HGD to adenocarcinoma. These studies comparing 3D-OCT images with histology are promising in improving In Vivo evaluation of esophageal nodules in the future. ACKNOWLEDGEMENT: NIH 5R01CA075289-14 and AFOSR FA9550-07-1-0101.

Reversibility of Optical-Cleared Porcine Ileal Specimens Enables Integration of 3-Dimensional Microscopy With the Standard H&E Tissue Analysis

BACKGROUND/AIMS: Endoscopic mucosal resection (EMR) has been an effective method to assess patients with esophageal nodules arising in Barrett's esophagus (BE). Optical Coherence Tomography (OCT) enables real-time, three-dimensional (3D) imaging of tissue microstructure, with resolution approaching histology and can be used to evaluate pathological features both In Vivo and within EMR specimens. In comparison, the latter is difficult to assess on confocal endoscopy which depends on In Vivo fluorescein to achieve optimal images . METHODS: A prototype OCT imaging system was developed in collaboration with the LightLab imaging Inc., providing images with an axial resolution of ~5um in tissue and ~15um along the transverse dimension. The OCT system has an axial scanning rate of ~59kHz and the system sensitivity is 103dB. The in-house developed fiberoptic imaging probe (2.5mm in diameter) can pass through the working channel of the endoscope. A 3DOCT dataset covering an imaging area of 20 mm x 8 mm x 2 mm can be acquired in 20s. Standard EMR was performed on 12 patients using Duette (Cook Medical, Inc.). Twentyfour EMR specimens, including 9 benign, 6 BE, 2 BE with low-grade dysplasia, 1 BE with high grade dysplasia, and 6 early adenocarcinomas, were subsequently imaged with 3DOCT and sent for standard H&E histology. Imaging features identified in the OCT images were then compared with matching histology. RESULTS: Cross-sectional and en face images could be reconstructed from the 3D-OCT dataset. Cross-sectional OCT image showed features matching with the corresponding histology. BE glands were observed at regions over the lamina propria layer while both the lamina propria layer and the muscular mucosa were preserved in 87% of OCT imaging dataset. En face OCT highlighted the distribution of the glandular structures in Barrett's esophagus and allowed quantification of BE gland density. In lesions with intramucosal and invasive adenocarcinoma, the muscular mucosa layer was less distinct or lost in the OCT images. This may be due to the destruction of tissue architecture or the thickened mucosa from the tumor. No lamina propria layer is identified in the datasets of 6 early adenocarcinomas. In addition, the shape and the distribution of the glandular structures were irregular compared to those of the BE glands. These distinctive patterns associated with adenocarcinoma were observed in both cross-sectional and en face OCT images. CONCLUSIONS: We demonstrated 3D-OCT images of EMR specimens of human esophagus ranging from benign nodules, BE with LGD, BE with HGD to adenocarcinoma. These studies comparing 3D-OCT images with histology are promising in improving In Vivo evaluation of esophageal nodules in the future. ACKNOWLEDGEMENT: NIH 5R01CA075289-14 and AFOSR FA9550-07-1-0101.

Regional functional specialization and inhibitory nitrergic and nonnitrergic coneurotransmission in the human esophagus

The aim of this study was to explore the myenteric mechanisms of control of human esophageal motility and the effect of nitrergic and nonnitrergic neurotransmitters. Human circular esophageal strips were studied in organ baths and with microelectrodes. Responses following electrical field stimulation (EFS) of enteric motoneurons (EMNs) or through nicotinic acetylcholine receptors were compared in the esophageal body (EB) and in clasp and sling regions in the lower esophageal sphincter (LES). In clasp LES strips: 1) sodium nitroprusside (1 nM to 100 μM), adenosine-5'-[β-thio]diphosphate trilithium salt (1-100 μM), and vasoactive intestinal peptide (1 nM to 1 μM) caused a relaxation; 2) 1 mM N(ω)-nitro-L-arginine (L-NNA) shifted the EFS "on"-relaxation to an "off"-relaxation, partly antagonized by 10 μM 2'-deoxy-N(6)-methyladenosine 3',5'-bisphosphate tetrasodium salt (MRS2179) or 10 U/ml α-chymotrypsin; and 3) nicotine-relaxation (100 μM) was mainly antagonized by L-NNA, and only partly by MRS2179 or α-chymotrypsin. In sling LES fibers, EFS and nicotine relaxation was abolished by L-NNA. In the EB, L-NNA blocked the latency period, and MRS2179 reduced "off"-contraction. The amplitude of cholinergic contraction decreased from the EB to both LES sides. EFS induced a monophasic inhibitory junction potential in clasp, sling, and EB fibers abolished by L-NNA. Our study shows a regional specialization to stimulation of EMNs in the human esophagus, with stronger inhibitory responses in clasp LES fibers and stronger cholinergic excitatory responses in the EB. Inhibitory responses are mainly triggered by nitrergic EMNs mediating the inhibitory junction potentials in the LES and EB, EFS on-relaxation in clasp and sling LES sides, and latency in the EB. We also found a minor role for purines (through P2Y(1) receptors) and vasoactive intestinal peptide-mediating part of nonnitrergic clasp LES relaxation.

Heat treatment of human esophageal tissues: Effect on esophageal cancer detection using oxygenated hemoglobin diffuse reflectance ratio

The main objective of the present work is to study the influence of heat treatment on the esophageal cancer detection using the diffuse reflectance (DR) spectral intensity ratio R540/R575 of oxygenated hemoglobin (HbO2) absorption bands to distinguish the epithelial tissues of normal human esophagus and moderately differentiated esophageal squamous cell carcinoma (ESCC) at different heat treatment temperature of 20, 37, 42, 50, and 60°C, respectively. The DR spectra for the epithelial tissues of the normal esophagus and ESCC in vitro at different heat-treatment temperature in the wavelength range 400–650 nm were measured with a commercial optical fiber spectrometer. The results indicate that the average DR spectral intensity overall enhancement with concomitant increase of heat-treatment temperature for the epithelial tissues of normal esophagus and ESCC, but the average DR spectral intensity for the normal esophageal epithelial tissues is relatively higher than that for ESCC epithelial tissues at the same heat-treatment temperature. The mean R540/R575 ratios of ESCC epithelial tissues were always lower than that of normal esophageal epithelial tissues at the same temperature, and the mean R540/R575 ratios of the epithelial tissues of the normal esophagus and ESCC were decreasing with the increase of different heat-treatment temperatures. The differences in the mean R540/R575 ratios between the epithelial tissues of normal esophagus and ESCC were 13.33, 13.59, 11.76, and 11.11% at different heat-treatment temperature of 20, 37, 42, and 50°C, respectively. These results also indicate that the DR intensity ratio R540/R575 of the hemoglobin bands is a useful tool for discrimination between the epithelial tissues of normal esophagus and ESCC in the temperature range from room temperature to 50°C, but it was non-effective at 60°C or over 60°C.

AFM stiffness nanotomography of normal, metaplastic and dysplastic human esophageal cells

The mechanical stiffness of individual cells is important in tissue homeostasis, cell growth, division and motility, and the epithelial–mesenchymal transition in the initiation of cancer. In this work, a normal squamous cell line (EPC2) and metaplastic (CP-A) as well as dysplastic (CP-D) Barrett's Esophagus columnar cell lines are studied as a model of pre-neoplastic progression in the human esophagus. We used the combination of an atomic force microscope (AFM) with a scanning confocal fluorescence lifetime imaging microscope to study the mechanical properties of single adherent cells. Sixty four force indentation curves were taken over the nucleus of each cell in an 8 × 8 grid pattern. Analyzing the force indentation curves, indentation depth-dependent Young's moduli were found for all cell lines. Stiffness tomograms demonstrate distinct differences between the mechanical properties of the studied cell lines. Comparing the stiffness for indentation forces of 1 nN, most probable Young's moduli were calculated to 4.7 kPa for EPC2 (n = 18 cells), 3.1 kPa for CP-A (n = 10) and 2.6 kPa for CP-D (n = 19). We also tested the influence of nuclei and nucleoli staining organic dyes on the mechanical properties of the cells. For stained EPC2 cells (n = 5), significant stiffening was found (9.9 kPa), while CP-A cells (n = 5) showed no clear trend (2.9 kPa) and a slight softening was observed (2.1 kPa) in the case of CP-D cells (n = 16). Some force–indentation curves show non-monotonic discontinuities with segments of negative slope, resembling a sawtooth pattern. We found the incidence of these ‘breakthrough events’ to be highest in the dysplastic CP-D cells, intermediate in the metaplastic CP-A cells and lowest in the normal EPC2 cells. This observation suggests that the microscopic explanation for the increased compliance of cancerous and pre-cancerous cells may lie in their susceptibility to ‘crumble and yield’ rather than their ability to ‘bend and flex’.

AFM Stiffness Nanotomography of Normal, Metaplastic and Dysplastic Human Esophageal Cells

The mechanical stiffness of individual cells is important in tissue homeostasis, cell growth, division, and motility, and epithelial-mesenchymal transition in the initiation of cancer. In this work, a normal squamous cell line (EPC2) and metaplastic (CP-A) as well as dysplastic (CP-D) Barrett's Esophagus columnar cell line are studied as a model of pre-neoplastic progression in the human esophagus. We used the combination of an atomic force microscope (AFM) with a scanning confocal fluorescence lifetime imaging microscope (FLIM) to study the mechanical properties of single adherent cells.