Compact multicolor two-photon fluorescence microscopy enabled by tailorable continuum generation from self-phase modulation and dispersive wave generation.

By precisely managing fiber-optic nonlinearity with anomalous dispersion, we have demonstrated the control of generating plural few-optical-cycle pulses based on a 24-MHz Chromium:forsterite laser, allowing multicolor two-photon tissue imaging by wavelength mixing. The formation of high-order soliton and its efficient coupling to dispersive wave generation leads to phase-matched spectral broadening, and we have obtained a broadband continuum ranging from 830 nm to 1200 nm, delivering 5-nJ pulses with a pulse width of 10.5 fs using a piece of large-mode-area fiber. We locate the spectral enhancement at around 920 nm for the two-photon excitation of green fluorophores, and we can easily compress the resulting pulse close to its limited duration without the need for active pulse shaping. To optimize the wavelength mixing for sum-frequency excitation, we have realized the management of the power ratio and group delay between the soliton and dispersive wave by varying the initial pulse energy without additional delay control. We have thus demonstrated simultaneous three-color two-photon tissue imaging with contrast management between different signals. Our source optimization leads to efficient two-photon excitation reaching a 500-µm imaging depth under a low 14-mW illumination power. We believe our source development leads to an efficient and compact approach for driving multicolor two-photon fluorescence microscopy and other ultrafast investigations, such as strong-field-driven applications.

Low noise, self-phase-modulation-enabled femtosecond fiber sources tunable in 740-1236†nm for wide two-photon fluorescence microscopy applications.

We have demonstrated widely tunable Yb:fiber-based laser sources, aiming to replace Ti:sapphire lasers for the nJ-level ultrafast applications, especially for the uses of nonlinear light microscopy. We investigated the influence of different input parameters to obtain an expansive spectral broadening, enabled by self-phase modulation and further reshaped by self-steepening, in the normal dispersion regime before the fiber damage. We also discussed the compressibility and intensity fluctuations of the demonstrated pulses, to reach the transform-limited duration with a very low intensity noise. Most importantly, we have demonstrated clear two-photon fluorescence images from UV-absorbing fluorophores to deep red dye stains.

High serum Ephrin-B2 levels predict poor prognosis for patients with gastric cancer.

Gastric cancer is an intractable disease with a poor prognosis and limited treatment options. Its treatment remains a major clinical challenge worldwide. Ephrin-B2 is upregulated and involved in tumor growth in various types of cancer. However, the association between ephrin-B2 and prognosis of gastric cancer, and the potential of ephrin-B2 as a therapeutic target remains unknown. The present study investigated ephrin-B2 as a prognostic factor and a therapeutic target for gastric cancer. Reverse transcription-quantitative polymerase chain reaction was performed to detect the protein expression level of ephrin-B2 in gastric cancer serum samples (n=162) and healthy serum samples (n=165). It was revealed that the protein expression level of ephrin-B2 was significantly upregulated in gastric cancer serum samples compared with the healthy samples. Ephrin-B2 protein expression was associated with tumor size (P<0.001), metastasis (P=0.02) and TNM stage (P=0.03), and was indicated to be an independent prognostic factor for gastric cancer. Furthermore, the Kaplan-Meier survival curve demonstrated that patients with high ephrin-B2 protein expression had shorter overall and progression-free survival rates than those with low ephrin-B2 protein expression. Ephrin-B2 protein expression was induced by small interfering RNA (siRNA) transfection of HGC27 and MKN-45 cells, significantly impeding cell viability and inducing apoptosis of HGC27 and MKN-45 cells compared with the respective negative control (NC) group. Thus, to the best of our knowledge, the present study indicates that ephrin-B2 functions as an oncogene in gastric cancer, and that serum ephrin-B2 level may be a promising non-invasive prognostic indicator, as well as a therapeutic target for gastric cancer.

Haplotype analysis of CTLA4 gene and risk of esophageal squamous cell carcinoma in Anyang area of China.

BACKGROUND/AIMS: To study the effect of cytotoxic T-lymphocyte antigen 4 gene haplotypes to susceptibility of esophageal squamous cell carcinoma. METHODOLOGY: A gender- and age-matched case-control design was used in this study. PCR-RFLP method was used to detect the genotype of CTLA4 in 205 patients and 205 control individuals in the Anyang area. Furthermore, haplotypes were calculated by PHASE2.1 software. Finally, the conditional logistic regression analysis was carried out to analyze the relevance between the risk of ESCC and the genotypes or haplotypes of CTLA4 gene. RESULTS: The CTLA4 rs231775 and rs4553808 genotypes in patients with ESCC were significantly different from controls (p=0.004, p=0.023, respectively). The AG and AA genotypes of rs231775 were highly correlated with the risk of ESCC (Adjusted OR=2.280, 95%CI=1.433-3.629, p=0.001; Adjusted OR=2.192, 95%CI=1.229-3.911, p=0.008, respectively), and AG genotype of rs4553808 also increased the susceptibility of ESCC (Adjusted OR=1.848, 95%CI=1.220-2.800, p=0.004). Further study suggested that AAG haplotype may enhance the risk of ESCC (Adjusted OR=5.035, 95%CI=1.599-15.860, p=0.005), but GAA haplotype played a protective role (Adjusted OR=0.413, 95%CI=0.251-0.680, p=0.001). CONCLUSIONS: Our research confirmed that CTLA4 genetic variation was related to ESCC in the Anyang area and GAA haplotype was the protective factor of ESCC.

[Correlation of XPD gene with susceptibility to gastric cancer].

BACKGROUND AND OBJECTIVE: Mutations in DNA repair system are related to carcinogenesis. This study was to evaluate the correlations of polymorphisms and haplotypes of XPD gene with individual susceptibility to gastric cancer. METHODS: Genomic DNA were extracted from peripheral blood leukocytes of 207 gastric cancer patients and 212 healthy controls. Genotypes at codon 312 and codon 751 polymorphic sites were identified by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) or polymerase chain reaction-restriction fragment length polymorphism (PCR-PFLP), respectively. RESULTS: At codon 312, the frequency of GA or AA genotype was higher in the gastric cancer patients than in the healthy controls (P<0.01, OR=3.41, 95% CI: 2.06-4.79; P<0.01, OR=3.47, 95% CI: 1.39-8.68). No significant difference was found in the distribution of the polymorphism at codon 751 between the two groups (P>0.05). By the haplotype AA (codon 312A-codon 751A) analysis, the frequency of heterozygote (-/AA) or homozygote (AA/AA) was higher in the patients than in the controls (P<0.01,OR=2.81, 95% CI:1.82-4.34;P=0.02,OR=3.92, 95% CI:1.31-11.70, respectively). Whereas there were no significant differences of the other three haplotypes between the patients and the controls (P>0.05). CONCLUSIONS: The polymorphism of XPD at codon 312 might contribute to the etiology of gastric cancer. The haplotype AA (codon 312A-codon 751A) would be a critical risk factor of the susceptibility to gastric cancer.

[A clinical study of abnormal bone metabolism in patients with HBV liver cirrhosis].

OBJECTIVE: To study the pathogenesis of abnormal bone metabolism in patients with HBV liver cirrhosis. METHODS: NM-300 signal-energy X-ray absorptiometry system was used to measure the bone mineral density (BMD) in 61 liver cirrhosis patients and 30 age-matched healthy controls. The serum levels of 1,25(OH)2D3, parathyroid hormone (PTH), calcitonin (CT), bone gamma-carboxyglutamic acid-containing protein (BGP), IL-1beta, IL-6, tumor necrosis factor (TNF)alpha and urine crosslaps were also detected in these patients. RESULTS: BMD in patients with HBV liver cirrhosis was lower than those of the controls. The serum levels of 1,25(OH)2D3 and BGP in cirrhosis patients were lower than those in the controls, and they were much lower in the osteoporosis (OP) group than in the non-osteoporosis (NOP) group. The PTH and CT were higher significantly in the patients than in the controls. The changes of serum 1,25(OH)2D3 and BGP were correlated with the changes of BMD. The serum levels of IL-1beta, IL-6, TNFalpha and urine crosslaps in cirrhosis patients were higher than those of the controls, and they were much higher in the OP group than in the NOP group. We also found that the serum levels of IL-1beta, IL-6, TNFalpha and urine crosslaps had a negative correlation with BMD. CONCLUSIONS: These data suggest that bone formation is weakened and bone resorption is increased in patients with HBV liver cirrhosis, 1,25(OH)2D3 plays an important role in abnormal bone formation. Elevation of serum IL-1beta, IL-6, TNFalpha can accelerate bone resorption and cause hepatic bone disease (HBD). Taking 1,25(OH)2D3 and reducing the level of IL-1beta, IL-6, TNFalpha may be very important in preventing and treating HBD.

[Studies of the association between angiotensinogen gene regulation and cytokines in essential hypertension].

This study is to explore the association between M235T allele polymorphism of angiotensinogen (AGT) gene and cytokines using essential hypertension probands research method. In hypertensives and controls, polymerase chain reaction combined with restriction endonuclease digestion was used to detect the target genotype variation, and enzyme-lined immunosorbant assay (ELISA) was used to detect the cytokine concentrations (IL-1, IL-6, TNF). The results showed that in hypertensives AGT gene, TT genotype was 55.88%, MT 35.29% and MM 8.82%. The ratio of T/M allele frequency was 0.735/0.265. In controls AGT gene, TT genotype was 47.46%, MT 42.37% and MM 10.17%. The ratio of T/M allele frequency was 0.686/0.314. AGT gene 235 T allele frequency in hypertensives was slightly higher than those in controls. Furthermore AGT gene 235 TT genotype and T allele frequency in middle and high grade of hypertensives were significantly higher than those in mild grade. In subjects of AGT 235 T allele group, the concentrations of IL-1, IL-6 and TNF in hypertensives were significantly higher than those in controls. In subjects of AGT gene 235 M allele frequency, the concentrations of IL-1 and IL-6 in hypertensives were no significant than those in controls. No matter in groups more than 60 years old or less than 60 years old, the concentrations of IL-1, IL-6 and TNF in hypertensives were higher than those in controls. No matter in hypertensives or controls, there were no differences in concentrations of IL-1, IL-6 and TNF when comparing groups more than 60 years old with groups less than 60 years old. The study indicated that AGT gene TT genotype and AGT gene 235 T allele frequency may be an important risk factor for hypertension. The high frequency of AGT gene 235 T allele and the high concentrations of IL-1, IL-6 and TNF in hypertensives may cause hypertension developing. It is also suggested the cytokines may effect the transcription and expression of AGT gene 235 TT genotype in hypertension. The concentrations of IL-1, IL-6 and TNF had nothing to do with age no matter hypertensives or controls.