Adaptive instantaneous frequency ridge extraction based on target tracking for frequency-modulated signals.

The instantaneous frequency (IF) is an important feature for the analysis of non-stationary signals. However, extracting multiple IF ridges, crossing IF ridges, and discontinuous IF ridges simultaneously is still a challenging task. To solve this problem, an adaptive IF ridge extraction method is proposed. This method regards the IF ridge values at each time point as targets to be tracked. The tracking targets are defined as three states: survival, death, and birth. Firstly, the potential peaks in the time-frequency representation are found to reduce the noise effect. Secondly, an adaptive penalty function is constructed to determine the target state and track the ridge target. Thirdly, the crossing ridges are separated base on the slope information. This method is capable of simultaneously extracting multiple IF ridges, crossing IF ridges, and discontinuous IF ridges. The performance of the proposed method is investigated by a simulated signal and two experimental signals.

In Situ Assay of Proteins Incorporated with Unnatural Amino Acids in Single Living Cells by Differenced Resonance Light Scattering Correlation Spectroscopy.

Site-specific incorporation of unnatural amino acids (UAAs) into target proteins (UAA-proteins) provides the unprecedented opportunities to study cell biology and biomedicine. However, it is a big challenge to in situ quantitatively determine the expression level of UAA-proteins due to serious interferences from autofluorescence, background scattering, and different viscosity in living cells. Here, we proposed a novel single nanoparticle spectroscopy method, differenced resonance light scattering correlation spectroscopy (D-RLSCS), to measure the UAA-proteins in single living cells. The D-RLSCS principle is based on the simultaneous measurement of the resonance scattering light fluctuation of a single gold nanoparticle (GNP) in two detection channels irradiated by two coaxial laser beams and then autocorrelation analysis on the differenced fluctuation signals between two channels. D-RLSCS can avoid the interferences from intracellular background scattering and provide the concentration and rotational and translational diffusion information of GNPs in solution or in living cells. Furthermore, we proposed a parameter, the ratiometric diffusion time and found that this parameter is proportional to the square of particle size. The theoretical and experimental results demonstrated that the ratiometric diffusion time was not influenced by the intracellular viscosity. This method was successfully applied for in situ quantification of the UAA-protein within single living cells based on the increase in the ratiometric diffusion time of nanoprobes bound with proteins. Using UAA-EGFP (enhanced green fluorescent protein) as a model, we observed the significant difference in the UAA-protein concentrations at different positions in single living cells.

Studying Homo-oligomerization and Hetero-oligomerization of MDMX and MDM2 Proteins in Single Living Cells by Using In Situ Fluorescence Correlation Spectroscopy.

Protein oligomerization plays a very important role in many physiological processes. p53 acts as a key tumor suppressor by regulating cell cycle arrest, DNA repair, and apoptosis, and its antitumor activity is regulated by the hetero- and homo-oligomerization of MDMX and MDM2 proteins. So far, some traditional methods have been utilized to study the oligomerization of MDMX and MDM2 in vitro, but they have not clarified some controversial issues or whether the extracellular results can represent the intracellular results. Here, we put forward an in situ method for studying protein homo- and hetero-oligomerization in single living cells by using fluorescence correlation spectroscopy. In this study, MDMX and MDM2 were labeled with fluorescent proteins using lentiviral transfection. Autocorrelation spectroscopy and cross-correlation spectroscopy methods were used to study the oligomerization of MDMX and MDM2 in situ and the effect of regulation of MDMX oligomerization on p53-MDMX interactions in single living cells. We observed the homo- and hetero-oligomerization of MDMX and MDM2 in living cells. Meanwhile, the levels of the homo-oligomers of MDMX and MDM2 were increased due to the lack of hetero-oligomerization. Finally, the binding affinity of MDMX for p53 was improved with an increase in the level of MDMX hetero-oligomerization.

Analyses of p73 Protein Oligomerization and p73-MDM2 Interaction in Single Living Cells Using In Situ Single Molecule Spectroscopy.

Protein oligomerization and protein-protein interaction are crucial to regulate protein functions and biological processes. p73 protein is a very important transcriptional factor and can promote apoptosis and cell cycle arrest, and its transcriptional activity is regulated by p73 oligomerization and p73-MDM2 interaction. Although extracellular studies on p73 oligomerization and p73-MDM2 interaction have been carried out, it is unclear how p73 oligomerization and p73-MDM2 interaction occur in living cells. In our study, we described an in situ method for studying p73 oligomerization and p73-MDM2 interaction in living cells by combining fluorescence cross-correlation spectroscopy with a fluorescent protein labeling technique. Lentiviral transfection was used to transfect cells with a plasmid for either p73 or MDM2, each fused to a different fluorescent protein. p73 oligomerization was evaluated using brightness per particle, and the p73-MDM2 interaction was quantified using the cross-correlation value. We constructed a series of p73 mutants in three domains (transactivation domain, DNA binding domain, and oligomerization domain) and MDM2 mutants. We systematically studied p73 oligomerization and the effects of p73 oligomerization and the p73 and MDM2 structures on the p73-MDM2 interaction in single living cells. We have found that the p73 protein can form oligomers and that the p73 structure changes in the oligomerization domain significantly influence its oligomerization. p73 oligomerization and the structure changes significantly affect the p73-MDM2 interaction. Furthermore, the effects of inhibitors on p73 oligomerization and p73-MDM2 interaction were studied.

In Situ Study of Interactions between Endogenous c-myc mRNA with CRDBP in a Single Living Cell by Combining Fluorescence Cross-Correlation Spectroscopy with Molecular Beacons.

mRNA-protein interactions play key roles in facilitating various biological functions in gene expression regulations and even the progression of diseases. However, it is still a challenge to directly monitor mRNA-protein interactions in a single living cell at present. Herein, we propose a new strategy for real-time studying of mRNA-protein interactions in a single living cell using fluorescence cross-correlation spectroscopy (FCCS) and molecular beacon (MB) labeling techniques. The c-myc mRNA and coding region determinant binding protein (CRDBP) were used as models. We first evaluated the performances of unmodified (2'-deoxy) and modified (2'-O-methyl) MBs and found that the 2'-O-methyl loop MB (2'-O-methyl loop domain, 2'-deoxy stem region) has high affinity to target mRNA and good nuclease resistance. Then we constructed stable cell line expressing mCherry-CRDBP using lentivirus infection, and on the basis of FCCS, we established an efficient method for quantifying the interaction of c-myc mRNA with CRDBP in a single living cell. The RNA binding domains of CRDBP cover two RNA recognition motifs (RRM) and four K homologies (KH). Furthermore, we constructed the truncated variants and point mutants on RNA binding domains of CRDBP, systematically studied the effects of RNA binding domains of CRDBP on c-myc mRNA-CRDBP interaction in living cells, and found that KH3-4 is indispensable for c-myc mRNA binding, KH1-2 plays a supplementary role, and RRM1-2 shows no binding ability to c-myc mRNA. Our work reveals the mechanisms of c-myc mRNA-CRDBP interactions and provides a general strategy for quantifying the interactions of endogenous mRNA with protein in a single living cell.

microRNA-32-5p targets KLF2 to promote gastric cancer by activating PI3K/AKT signaling pathway.

Krüppel-like factor 2 (KLF2) is a member of the zinc finger family, which is considered a potential tumor suppressor gene due to its reduced expression in gastric cancer. MicroRNAs (miRNAs) are a class of short non-coding single-stranded RNAs that are closely related to the development of gastric cancer. The purpose of this study was to investigate the miRNAs that regulate KLF2 and explore its specific mechanism in gastric cancer. Bioinformatics software Targetscan identified that microRNA-32-5p (miRNA-32-5p) may bind to KLF2 mRNA to regulate its expression. In order to verify the regulatory effect of miRNA-32-5p on KLF2, the proliferation and migration assays were performed in both KLF2 overexpression and KLF2 knockdown gastric cancer cells. Dual-Luciferase reporter assay proved that KLF2 could bind to the PTEN promoter to induce its expression. Moreover, research on molecular mechanisms indicated that both miRNA-32-5p and shKLF2 downregulated the expression of PTEN and activated the PI3K/AKT signaling to promote the development of gastric cancer. Targeting miRNA-32-5p and KLF2 is expected to provide new sign and target for gastric cancer treatment.

Wave Propagation in Aluminum Honeycomb Plate and Debonding Detection Using Scanning Laser Vibrometer.

Both the aerospace and marine industry have widely relied on a honeycomb sandwich structure (HSS) because of its high strength-to-weight ratio. However, the intrinsic nature of an adhesively bonded multi-layer structure increases the risk of debonding when the structure is under strain or exposed to varying temperatures. Such defects are normally concealed under the surface but can significantly compromise the strength and stiffness of a structure. In this paper, the guided wave method is used to detect debondings which are located between the skin and the honeycomb in sandwich plates. The propagation of guided waves in honeycomb plates is investigated via numerical techniques, with emphasis placed on demonstrating the behavior of structure-based wave interactions (SWIs). The SWI technique is effective to distinguish heterogeneous structures from homogeneous structures. The excitation frequency is necessary to generate obvious SWIs in HSSs; accordingly, a novel strategy is proposed to select the optimal excitation frequencies. A series of experiments are conducted, the results of which show that the presented procedure can be used to effectively detect the locations and the sizes of single- and multi-damage zones in HSSs.

In Situ Monitoring of p53 Protein and MDM2 Protein Interaction in Single Living Cells Using Single-Molecule Fluorescence Spectroscopy.

Protein-protein interactions play a central role in signal transduction, transcription regulations, enzymatic activity, and protein synthesis. The p53 protein is a key transcription factor, and its activity is precisely regulated by the p53-MDM2 interaction. Although the p53-MDM2 interaction has been studied, it is still not clear how p53 structures and external factors influence the p53-MDM2 interaction in living cells. Here, we developed a direct method for monitoring the p53-MDM2 interaction in single living cells using single-molecule fluorescence cross-correlation spectroscopy with a microfluidic chip. First, we labeled p53 and MDM2 proteins with enhanced green fluorescent protein (EGFP) and mCherry, respectively, using lentivirus infection. We then designed various mutants covering the three main domains of p53 (tetramerization, transactivation, and DNA-binding domains) and systematically studied effects of p53 protein primary, secondary, and quaternary structures on p53-MDM2 binding affinity in single living cells. We found that p53 dimers and tetramers can bind to MDM2, that the binding affinity of p53 tetramers is higher than that of p53 dimers, and that the affinity is closely correlated to the helicity of the p53 transactivation domain. The hot-spot mutation R175H in the DNA-binding domain reduced the binding of p53 to MDM2. Finally, we studied effects of inhibitors on p53-MDM2 interactions and dissociation dynamics of p53-MDM2 complexes in single living cells. We found that inhibitors Nutlin 3α and MI773 efficiently inhibited the p53-MDM2 interaction, but RITA did not work in living cells. This study provides a direct way for quantifying the relationship between protein structure and protein-protein interactions and evaluation of inhibitors in living cells.

Joint High-Order Synchrosqueezing Transform and Multi-Taper Empirical Wavelet Transform for Fault Diagnosis of Wind Turbine Planetary Gearbox under Nonstationary Conditions.

Wind turbines usually operate under nonstationary conditions, such as wide-range speed fluctuation and time-varying load. Its critical component, the planetary gearbox, is prone to malfunction or failure, which leads to downtime and repair costs. Therefore, fault diagnosis and condition monitoring for the planetary gearbox in wind turbines is a vital research topic. Meanwhile, the signals measured by the vibration sensors mounted in the gearbox exhibit time-varying and nonstationary features. In this study, a novel time-frequency method based on high-order synchrosqueezing transform (SST) and multi-taper empirical wavelet transform (MTEWT) is proposed for the wind turbine planetary gearbox under nonstationary conditions. The high-order SST uses accurate instantaneous frequency approximations to obtain a sharper time-frequency representation (TFR). As the acquired signal consists of many components, like the meshing and rotating components of the gear and bearing, the fault component may be masked by other unrelated components. The MTEWT is used to separate the fault feature from the masking components. A variety of experimental signals of the wind turbine planetary gearbox under nonstationary conditions have been analyzed to demonstrate the effectiveness and robustness of the proposed method. Results show that the proposed method is effective in diagnosing both gear and bearing faults.

A numerical study of non-collinear wave mixing and generated resonant components.

Interaction of two non-collinear nonlinear ultrasonic waves in an elastic half-space with quadratic nonlinearity is investigated in this paper. A hyperbolic system of conservation laws is applied here and a semi-discrete central scheme is used to solve the numerical problem. The numerical results validate that the model can be used as an effective method to generate and evaluate a resonant wave when two primary waves mix together under certain resonant conditions. Features of the resonant wave are analyzed both in the time and frequency domains, and variation trends of the resonant waves together with second harmonics along the propagation path are analyzed. Applied with the pulse-inversion technique, components of resonant waves and second harmonics can be independently extracted and observed without distinguishing times of flight. The results show that under the circumstance of non-collinear wave mixing, both sum and difference resonant components can be clearly obtained especially in the tangential direction of their propagation. For several rays of observation points around the interaction zone, the further it is away from the excitation sources, generally the earlier the maximum of amplitude arises. From the parametric analysis of the phased array, it is found that both the length of array and the density of element have impact on the maximum of amplitude of the resonant waves. The spatial distribution of resonant waves will provide necessary information for the related experiments.

[The study of expression of BRMS1 gene protein and the expression of BRMS1 gene promotor area methylation in supraglottic laryngeal carcinoma and its clinical significance].

OBJECTIVE: To investigate the expression of breast cancer metastasis suppressor 1 (BRMS1) gene protein and the expression of BRMS1 gene promotor area methylation in supraglottic cancer and to evaluate its clinical significance. METHOD: The expression of BRMS1 protein and BRMS1 gene promotor area methylation were examined by using Western blotting method and methylation-specific polymerase chain reaction(MSP) method in 70 cases of supraglottic cancer tissues and 60 cases of their surrounding laryngeal normal mucosa tissues (LNT) and 44 cases of cervical lymph node metastasis of supraglottic cancer. RESULT: Western blot results indicate that BRMS1 protein expression is declined expression level in supraglottic cancer tissue than the expression of BRMS1 protein in LNT of supraglottic cancer. Compared with para carcinoma normal laryngeal mucous tissue, BRMS1 gene protein in supraglottic cancer tissue primary lesion decreased obviously, and it is decreased more obviously in cervical lymph node metastasis lesion, the discrepancy is notable (P < 0.05). MSP results indicate BRMS1 gene promotor methylation is coordinated with its down-expression in supraglottic cancer tissue. BRMS1 promotor area methylation analysis reveal that there were 34 patients with methylation in 70 patients' supraglottic cancer tumor primary lesion, hold 48.6% (34/70); 32 patients have methylation in 44 patients' cervical metastasis lymph node tissue, hold 72.7% (32/44); however, there is no methylation in 60 para carcinoma tissue (r(s) = 0.66, P < 0.05). CONCLUSION: The expression of BRMS1 protein in supraglottic cancer is significantly decreased. It had correlation with clinical stage and pathologic differentiation and cervical lymph node metastasis of supraglottic cancer. BRMS1 gene promotor methylation is related with down-expression of BRMS1 gene protein of supraglottic cancer. Maybe BRMS1 gene promotor methylation is one of the reasons of its down-expression.

NF-κB induces abnormal centrosome amplification by upregulation of CDK2 in laryngeal squamous cell cancer.

Centrosome amplification can drive chromosomal instability (CIN) which is a major source of tumor initiation. The present study aimed to investigate the impact of nuclear factor kappa B (NF-κB) on centrosome amplification of Hep-2 cells. Immunofluorescence was performed to display centrosomes. BAY11-7082 was used as an inhibitor of NF-κB to assess the inhibition of centrosome amplification, and cyclin-dependent kinase 2 (CDK2), ensuring cell cycle cycle coordination with centrosome cycle was detected by Western blotting. Furthermore, a 1556-bp fragment of the CDK2 promoter was analyzed using the TRANSFAC-TESS software. Luciferase assay, including a series of truncated CDK2 promoters and site mutations, was carried out to determine NF-κB binding sites in the CDK2 promoter. Electrophoresis mobility shift and chromatin immunoprecipitation assays were applied to confirm whether NF-κB indeed binds to the 5'-promoter region of the CDK2 gene. To reveal the clinical significance of CDK2 expression in laryngeal squamous cell cancer, mRNA and protein levels were assessed by RT-PCR and Western blotting, respectively. We found that the transcription factor NF-κB plays a role in centrosome amplification in Hep-2 cells. Centrosome amplification is reduced by inhibition of the NF-κB pathway. Moreover, expression of the p65 subunit of NF-κB is sufficient to promote centrosome amplification and increase in CDK2 protein levels. We further identified a functional NF-κB binding site located in the CDK2 promoter. Single mutation of the NF-κB site III (construct mutIII) however resulted in 76±5% (p<0.01) luciferase activity reduction. Electromobility shift assays and chromatin immunoprecipitaton results suggest that NF-κB indeed binds to this responsive element associating with CDK2 expression and centrosome amplification. RT-PCR and Western blotting results revealed that both mRNA and protein levels of CDK2 were significantly higher in tumor tissues than those in paired adjacent normal laryngeal tissues.

[Teaching experience in integrated course of human development and genetics].

Establishment of integrated course system in human development and genetics is an important part of course reformation, and the improvement of this system is achieved by integrating the content of course, stabilizing teaching force, building teaching materials and applying problem-based learning. Integrity-PBL teaching model is founded and proved to be feasible and effective by teaching practice. Therefore, it maybe play an important role in improving teaching effect and cultivating ability of students to analyse and solve problems.

A fiber optic Doppler sensor and its application in debonding detection for composite structures.

Debonding is one of the most important damage forms in fiber-reinforced composite structures. This work was devoted to the debonding damage detection of lap splice joints in carbon fiber reinforced plastic (CFRP) structures, which is based on guided ultrasonic wave signals captured by using fiber optic Doppler (FOD) sensor with spiral shape. Interferometers based on two types of laser sources, namely the He-Ne laser and the infrared semiconductor laser, are proposed and compared in this study for the purpose of measuring Doppler frequency shift of the FOD sensor. Locations of the FOD sensors are optimized based on mechanical characteristics of lap splice joint. The FOD sensors are subsequently used to detect the guided ultrasonic waves propagating in the CFRP structures. By taking advantage of signal processing approaches, features of the guided wave signals can be revealed. The results demonstrate that debonding in the lap splice joint results in arrival time delay of the first package in the guided wave signals, which can be the characteristic for debonding damage inspection and damage extent estimation.

[Expression of gene BRMS1 and CD44v6 protein in supraglottic laryngeal carcinoma and its clinical significance].

OBJECTIVE: To investigate the expression of breast cancer metastasis suppressor 1 (BRMS1) and CD44v6 protein in supraglottic cancer and to evaluate its clinical significance. METHOD: The expression of BRMS1 protein and CD44v6 protein were examined by using immunohistochemical method in 70 cases of paraffin-embedded supraglottic cancer tissues and their surrounding laryngeal normal mucosa tissues (LNT). RESULT: The expression of BRMS1 protein in LNT of supraglottic cancer was positive, and the positive rate was 85.7% (60/70); in tumor tissue was negative or lower expression, and the positive rate was 35.7% (25/70). The expression of CD44v6 protein in tumor tissue of supraglottic cancer was positive, the positive rate was 82.9% (58/70), in LNT was negative. There was a significant difference in BRMS1 and CD44v6 protein expression between the supraglottic cancer tissue and LNT (P<0.01). The expression of BRMS1 and CD44v6 protein had correlation with clinical stage and pathologic differentiation and cervical lymph node metastasis of supraglottic cancer (P<0.01). No correlation was found between the two proteins expression and sex and age (P>0.05). The expression of BRMS1 protein was related to the expression of CD44v6 protein (r = -0.9042, P<0.01). Calculated by Kaplan-Meier method, there is no survival difference at 3-year between the group with positive BRMS1 protein expression and the group with negative BRMS1 protein expression in tumor tissues (P>0.05), there is a significant survival difference at 3-year between the group with positive CD44v6 protein expression and the group with negative CD44v6 protein expression in tumor tissues (P<0.05). CONCLUSION: The expression of BRMS1 protein in supraglottic cancer is significantly decreased and the expression of CD44v6 protein in supraglottic cancer is significantly increased. The expression of BRMS1 protein and CD44v6 protein has a close relationship with pathologic differentiation and clinical stage and cervical lymph node metastasis of supraglottic cancer. Combined detection of the expression of them in supraglottic cancer may provide a significant parameter to judge the cervical lymph node metastasis of supraglottic cancer.

Guided wave and damage detection in composite laminates using different fiber optic sensors.

Guided wave detection using different fiber optic sensors and their applications in damage detection for composite laminates were systematically investigated and compared in this paper. Two types of fiber optic sensors, namely fiber Bragg gratings (FBG) and Doppler effect-based fiber optic (FOD) sensors, were addressed and guided wave detection systems were constructed for both types. Guided waves generated by a piezoelectric transducer were propagated through a quasi-isotropic carbon fiber reinforced plastic (CFRP) laminate and acquired by these fiber optic sensors. Characteristics of these fiber optic sensors in ultrasonic guided wave detection were systematically compared. Results demonstrated that both the FBG and FOD sensors can be applied in guided wave and damage detection for the CFRP laminates. The signal-to-noise ratio (SNR) of guided wave signal captured by an FOD sensor is relatively high in comparison with that of the FBG sensor because of their different physical principles in ultrasonic detection. Further, the FOD sensor is sensitive to the damage-induced fundamental shear horizontal (SH(0)) guided wave that, however, cannot be detected by using the FBG sensor, because the FOD sensor is omnidirectional in ultrasound detection and, in contrast, the FBG sensor is severely direction dependent.

[The mutation and expression of MUS81 gene in laryngeal squamous cell carcinoma].

OBJECTIVE: To investigate the association of mutations and expression of MUS81 gene with the tumorigenesis and progression of laryngeal squamous cell carcinoma (LSCC). METHODS: PCR-SSCP and DNA sequencing were carried out to examine mutations at exons 9 and 10 of MUS81 gene in 42 LSCC samples, with paired adjacent normal laryngeal tissues (PANLs) as control. Semi-quantitative RT-PCR and Western blot were used to detect the expression of MUS81 gene in the specimens. RESULTS: No mutation was detected in the control group. Among the 42 LSCC specimens, nineteen (45.2%) were found to harbor mutations, including 11(26.2%) occurring within exon 9, and 8 (19%) within exon 10. Seventeen (40.48%) samples showed lower mRNA level of the MUS81 gene (P<0.01), and same proportion of samples had lower protein level (P<0.01), suggesting that MUS81 gene was similarly down-regulated at both mRNA and protein levels in the LSCC samples. Furthermore, mutations of MUS81 gene did not significantly correlate with TNM stages, age and lymphoid node metastasis (P>0.05). Nor did the expression of MUS81 gene with the TNM stages, age and lymphoid node metastasis in LSCC (P>0.05). CONCLUSION: Mutations and abnormal expression of MUS81 gene in the LSCC tissues were observed, which suggested that abnormalities of MUS81 gene may play an important role in the tumorigenesis of LSCC.

[Expression and clinical significance of breast cancer metastasis suppressor 1 mRNA in supraglottic laryngeal carcinoma].

OBJECTIVE: To investigate the expression of breast cancer metastasis suppressor 1 (BRMS1) mRNA in supraglottic cancer and to evaluate its clinical significance. METHOD: The expression of BRMS1 mRNA was examined by using RT-PCR method which take beta-actin mRNA as reference template in 66 cases of supraglottic cancer tissues and their adjacent normal mucosa tissues (ANT). RESULT: The expression of BRMS1 mRNA in the tissues of supraglottic cancer is lower significantly than that in the tissues of ANT ( P<0.05). There is correlation between BRMS1 mRNA expression and the clinical stage, differentiation and cervical lymph node metastasis in the laryngeal supraglottic cancers (P<0.05). There is no correlation between BRMS1 mRNA expression and sex and age. CONCLUSION: Expression of BRMS1 mRNA in supraglottic cancer is lower than that in adjacent normal mucosa. The decrease of BRMS1 mRNA expression may be related to clinical stage and low differentiation and lymph node metastasis of supraglottic laryngeal cancer.

A combined strategy of conventional cytogenetics, fluorescent in situ hybridization and microsatellite polymerase chain reaction to analyze the deletion of chromosome 6 in laryngeal squamous cell carcinoma.

Laryngeal squamous cell carcinoma (LSCC) is a common cancer of the upper respiratory tract. The cytogenetic and molecular events involved in the pathogenesis of LSCC are not well understood. In this study, a combined strategy of conventional cytogenetics, fluorescent in situ hybridization (FISH) and microsatellite polymerase chain reaction was performed to analyze the deletion of chromosome 6 in LSCC. Karyotype analysis indicated that the deletions of 6q were marker chromosomes potentially specific to LSCC. To further characterize the loss of 6q, metaphase cells derived from both solid tumors and the Hep-2 cell line were investigated using FISH, with results consistent with those of conventional cytogenetics. Moreover, tumor-adjacent normal tissue DNA pairs from 70 LSCC in China were analyzed for loss of heterozygosity (LOH) and microsatellite instability (MI) on chromosome 6q in the region 6q25 by polymerase chain reaction (PCR) and three microsatellite markers. Overall, the highest frequency of microsatellite alteration (68.2%) was located at D6S980, which revealed that the region around D6S980 in 6q25 might harbor some important genes related to the pathogenesis of LSCC in Chinese patients. The pattern of chromosomal changes detected using the combined strategy suggests that it will become the most suitable way to find novel cancer-related genes and discover the relationship between the aberration of genetics and their tumorigenic mechanism.

[Analysis of chromosome aberrations in the cell derived from primary cell culture of laryngeal carcinoma and the Hep-2 cell line].

OBJECTIVE: To search for characteristic chromosome changes in primary laryngeal squamous cell carcinoma (LSCC) and Hep-2 cell line and to realize the relationship between the cytogenetic abnormality and the pathogenetic mechanism in LSCC. METHODS: The fresh resulted samples of LSCC were analyzed with an improved primary cell culture for chromosome preparation and G-banding technique. Hep-2 cell line was analyzed by high resolution banding technique. Molecular cytogenetics analysis was made by chromosome 6 painting probe. RESULTS: Four primary LSCC succeeded in primary cell culture and obtained metaphases, one was tetraploid, the other three were triploid. The chromosome mode of Hep-2 cell line was from 68 to 75 and fifteen marker chromosomes were found. The most structural abnormalities of chromosome in primary LSCC and HEP-2 cell line were unbalance translocation, terminal deletion and isochromosome. The complicate aberration in chromosome 6 was common in LSCC and Hep-2. CONCLUSION: 6q-, I(5p), 17p-, 5q- are considered as characteristic chomosome changs in LSCC. Fluorescence in situ hybridization (FISH) may enhance the ability of detecting complicated chromosome rearrangements and marker chromosomes, which could provide more value data to verify the chromosome characteristic aberration in LSCC.