Effect of an low-energy Nd: YAG laser on periodontal ligament stem cell homing through the SDF-1/CXCR4 signaling pathway.

BACKGROUND: The key to the success of endogenous regeneration is to improve the homing rate of stem cells, and low-energy laser is an effective auxiliary means to promote cell migration and proliferation. The purpose of this study was to observe whether low-energy neodymium (Nd: YAG) laser with appropriate parameters can affect the proliferation and migration of periodontal ligament stem cells (PDLSCs) through SDF-1/CXCR4 pathway. METHODS: h PDLSCs were cultured and identified. CCK8 assay was used to detect the proliferation of h PDLSCs after different power (0, 0.25, 0.5, 1, and 1.5 W) Nd: YAG laser (MSP, 10 Hz, 30 s, 300 µ m) irradiation at 2th, 3rd,5th, and 7th days, and the optimal laser irradiation parameters were selected for subsequent experiments. Then, the cells were categorized into five groups: control group (C), SDF-1 group (S), AMD3100 group (A), Nd: YAG laser irradiation group (N), and Nd: YAG laser irradiation + AMD3100 group (N + A). the migration of h PDLSCs was observed using Transwell, and the SDF-1 expression was evaluated using ELISA andRT-PCR. The SPSS Statistics 21.0 software was used for statistical analysis. RESULTS: The fibroblasts cultured were identified as h PDLSCs. Compared with the C, when the power was 1 W, the proliferation rate of h PDLSCs was accelerated (P < 0.05). When the power was 1.5 W, the proliferation rate decreased (P < 0.05). When the power was 0.25 and 0.5 W, no statistically significant difference in the proliferation rate was observed (P > 0.05). The number of cell perforations values as follows: C (956.5 ± 51.74), A (981.5 ± 21.15), S (1253 ± 87.21), N (1336 ± 48.54), and N + A (1044 ± 22.13), that increased significantly in group N (P < 0.05), but decreased in group N + A (P < 0.05). The level of SDF-1 and the expression level of SDF-1 mRNA in groups N and N + A was higher than that in group C (P < 0.05) but lower than that in group A (P < 0.05). CONCLUSIONS: Nd: YAG laser irradiation with appropriate parameters provides a new method for endogenous regeneration of periodontal tissue. SDF-1/CXCR4 signaling pathway may be the mechanism of LLLT promoting periodontal regeneration.

ß-Glycyrrhetinic acid inhibits the bacterial growth and biofilm formation by supragingival plaque commensals.

ß-Glycyrrhetinic acid (BGA) is a natural antibacterial agent. Previous studies reported that BGA has antibacterial effects against several bacteria. This study evaluated the effects of BGA on the regulation of supragingival plaque bacteria. First, the minimum inhibitory concentrations (MICs) of BGA against oral bacteria were measured. Next, the minimum concentrations for inhibition of biofilm formation were evaluated against Streptococcus mutans and Streptococcus sobrinus, possessing insoluble glucan synthesis abilities. The MICs of biofilm formation by these bacteria ranged from 1/8 to 2× MIC. Furthermore, the inhibition effects of BGA against the coaggregation of Porphyromonas gingivalis and Streptococcus gordonii were evaluated. BGA at 32 or 64 µg/mL inhibited the coaggregation of these bacteria after a 30 min incubation. Lastly, the inhibition effects of BGA against human supragingival plaque bacteria were evaluated. Human supragingival plaque samples were obtained from 12 healthy donors. The inhibition effects of BGA against biofilm formation by these plaque bacteria were evaluated. Of 12 samples, the biofilm formation by 11 was significantly attenuated by 128-256 µg/mL of BGA. The number of colony forming units in these biofilms was also significantly attenuated. In conclusion, it was revealed that BGA inhibits the growth and biofilm formation of bacteria, furthermore, the same effect was confirmed with supragingival plaque bacteria. BGA is a good candidate for a natural agent that prevents the outbreak and progression of periodontal disease because it suppresses not only the growth and biofilm formation of bacteria, but also the coaggregation of P. gingivalis with plaque bacteria.

[Forensic analysis of 24 dismembered homicide cases in Shanghai].

OBJECTIVE: To explore the characteristics of the dismembered homicide cases in Shanghai and to provide the valuable guidance for forensic pathological practices. METHODS: Twenty-four cases of dismembered homicides were selected from 2005 to 2012 in Institute of Forensic Science, Shanghai Public Security Bureau. The general information of the victims and suspects, cause of death, criminal motive, postmortem body parts, tools and information of discarding body parts were retrospectively analyzed. RESULTS: Among the 24 dismembered homicide cases, victims were female in 16 cases, and suspects were male in 23 cases and were acquaintances in 22 cases. The main causes of death were mechanical asphyxia and traumatic brain injury. Most of the criminal motives were emotional disputes. The number of postmortem body parts was commonly from 20 to 30. The tools were mainly sharp instruments, including kitchen knives used in 20 cases. The postmortem body parts were discarded to different transregional areas, mainly using vehicles. CONCLUSION: The dismembered homicide cases in Shanghai show the following characteristics: the number of postmortem body parts is in large quantity; the methods of dismembered corpse are complex and different; the job characteristics of suspects are difficult to determine; the distance from homicide scene is far and the vehicles are commonly used.

[Study on electrical current mark with environmental scanning electron microscopy and energy dispersive X-ray microanalyser].

OBJECTIVE: To provide objective proof on diagnosis of electrical current mark in electrocution, the environmental scanning electron microscopy and energy dispersive X-ray microanalyser (ESEM-EDX) were adopted to study the microscopic morphological characteristics and elemental composition of electrical current mark. METHODS: Morphological characteristics of electrical current marks, the elemental composition and morphology of metal particles were studied with ESEM-EDX. RESULTS: The electroporation and metal melted beads could be found in the electrical current marks and skin around them. The metal melted beads mainly composed of common metal such as iron, copper, aluminum and some uncommon metal including gold, titanium and barium. CONCLUSION: ESEM-EDX can be applied in forensic diagnosis of electrocution.

[Molecular mechanism of cyclooxygenase-2 inhibitor in inhibition of proliferation of colon cancer cells by modulating Stat5 signal transduction pathway].

OBJECTIVE: To investigate the role of NS398, a selective cyclooxygenase (COX)-2 inhibitor, in proliferation and apoptosis of colorectal cancer, and to reveal the mechanism of inhibiting colon cancer by NS-398 Independent of COX-2. METHODS: Human colon cancer cells of the line SW480 were cultured and then divided into 2 groups: experimental group and control group. NS398 of the concentrations of 12.5, 25, 50, 75, 100, and 125 micromol/L was added into the culture fluid of the experimental group. MTT assay was used to observe the proliferation of the cells, flow cytometry was used to test the cell cycle, RT-PCR analysis was performed to examine COX-2 mRNA expression, and Western blotting analysis was performed to detect the expression of Stat5, peroxisome proliferators-activated receptors (PPARs), cyclin D1 and Bcl-x(L). RESULTS: Expression of COX-2 mRNA was not detected in the SW480 colon cancer cells. 72 hours after the addition of NS398 75 micromol/L the proliferative level of the SW480 cells was decreased; the rate of the cells at the G(1) stage increased from 31.2% to 40.6%, and the rate of cells at the S stage decreased from 52.8% to 41.2%. The expression of Stat5, PPARdelta, cyclin D1 and Bcl-x(L) decreased along with the elongation of time of NS398 action. CONCLUSION: COX-2 inhibitor, such as NS-398 inhibits the colon cancer cell proliferation and induces apoptosis of colon cancer cells with the possible mechanism of inhibiting the proliferation and inducing the apoptosis of colon cancer cells through a pathway independent of COX-2.

Constitutive activation of Stat3 signaling pathway in human colorectal carcinoma.

AIM: Signal transducers and activators of transcription (STATs) are a family of transcription factors activated in response to cytokines and growth factors. Constitutive activation of Stat3 has been observed in a growing number of tumor-derived cell lines, as well as tumor specimens from human cancers. The purpose of this study was to investigate the expression of p-Stat3, activated form of Stat3, and its downstream mediators including cyclin D1 and Bcl-x(L) in colorectal carcinoma (CRC), and to explore the possible mechanism of Stat3 signaling pathway in the tumorigenesis of colorectal carcinoma. METHODS: Tissue samples from 45 patients of primary colorectal carcinoma were selected for studying Stat3 signaling pathway protein expression. Western blot analysis was used to measure the expression of p-Stat3, cyclin D1, and Bcl-x(L) proteins in colorectal carcinomas. Furthermore, the expression patterns of these proteins were analyzed for their distribution at the cellular level by immunohistochemical staining of the tissues. RESULTS: Protein levels of p-Stat3, cyclin D1, and Bcl-x(L) were increased in colorectal carcinomas compared with adjacent normal mucosae (P<0.05). Elevated levels of p-Stat3 were correlated with the nodal metastasis and the stage (P<0.05). Overexpression of cyclin D1 was associated with the nodal metastasis (P<0.05). There was also a significant correlation between the expressions of p-Stat3 and cyclin D1 (r=0.382, P<0.05). CONCLUSION: Constitutive activation of Stat3 may play an important role in the tumorigenesis of colorectal carcinoma, and the detailed mechanism of Stat3 signaling pathway in CRC deserves further investigation.

[Stat3 signal transduction pathway orchestrates G1 to S cell cycle transition in colon cancer cells].

OBJECTIVE: To show that Stat3 plays a key role in the G1 to S phase transition in colon cancer cells. METHODS: Human colon cancer cell lines SW480 and HCT116 were transfected with Stat3 antisense oligonucleotide mediated by liposome, MTT assay was used to measure the proliferation, flow cytometry was applied to analyze the cell cycle, and the expressions of Stat3, phosphorylation-specific Stat3 (tyrosine 705), Cyclin D1, Cyclin E, CDK2, CDK4, CDK6, p21 and p27 were measured by western blot. RESULTS: SW480 and HCT116 colon cancer cell lines expressed constitutively activated Stat3. Targeting of Stat3 using antisense oligonucleotide which directed against the translation site resulted in growth inhibition, downregulation of Stat3, p-Stat3, Cyclins and CDKs, and up-regulation of p21 and p27. CONCLUSION: Our findings suggest that Stat3 plays an important role in the G1 to S phase transition in colon cancer cells, Stat3 orchestrates cell cycle by regulating the balance between CDK/Cyclin complex and CKI.

[Significance of MEK-ERK cascade in the development of human breast carcinoma].

OBJECTIVE: To investigate the MEK and ERK expression and their relationship with clinicopathological parameters in human breast carcinoma, and the effect of preoperative chemotherapy on MEK and ERK protein expression. METHODS: Samples were obtained from 56 patients with breast carcinoma and 8 patients with benign tumors. Sixteen of the 56 patients received preoperative chemotherapy. Western blot and immunohistochemistry were used to measure the expression of MEK1, MEK2 and ERK1, ERK2 protein. RESULTS: MEK2 and ERK1, ERK2 protein levels were increased in breast carcinoma tissue compared with those in adjacent normal tissues (t = 7.244, 5.959, 3.735, P < 0.01) and benign tumors (t = 2.206, P < 0.05). The levels of MEK1 were decreased. The expression of MEK2 protein in ER negative patients was higher than that in ER positive ones. MEK2 protein levels were lower in patients who received preoperative chemotherapy than in those who did not. CONCLUSION: Overexpression of MEK-ERK may play an important role in the development of human breast carcinoma. MEK and ERK protein expressions are inhibited by preoperative chemotherapy.

[A study on the risk factors of cardiovascular between hypertensive patients and normal subjects in the same family].

OBJECTIVE: Through studying the difference between the hypertensive patients and those with normal blood pressure who all from the same hypertensive pedigree, we tried to find the factors which would decrease the risk of hypertension. METHODS: Hypertensive patients, when coming to the cardiovascular clinic of Xuan Wu Hospital from 2003 to 2004, were defined as the members of the hypertensive pedigrees through inquiry. 84 families including 368 persons, with 192 syblings were involved. Metabolic syndrome could be defined by the criterion of adult treatment panel III. RESULTS: When compared with normal blood pressure persons, clinical examinations of the hypertensive patients had an higher levels of triglyceride, total cholesterol, glucose and body mass index (BMI). The hypertensive group showed higher ratios among male patients, smokers, alcohol drinkers, having irritable personality and high-salt-intake. Through logistic regression, overweight, smoking and irritable temperament showed positive relations with hypertension. The rate of metabolic syndrome was higher in hypertension group. CONCLUSION: It is important that either persons with normal blood pressure or hypertension should control their body weights (BMI) since the rate of metabolic syndrome in hypertension group was high.

[Relationship of Stat3 and its target gene products with malignancy in human colorectal carcinoma].

BACKGROUND & OBJECTIVE: Signal transducers and activators of transcription 3 (Stat3) pathway can be activated by cytokines and growth factors, and activation of Stat3 is involved in modulating cell proliferation, differentiation, and apoptosis. Stat3 has been classified as an oncogene because Stat3 can mediate malignant transformation of cultured cells. This study was conducted to investigate the expression of Stat3 and its target gene products including Cyclin D1 and Bcl-x(L) in human colorectal carcinoma (CRC) tissues and cells, and to explore the mechanisms in tumorigenesis of CRC. METHODS: The expression of Stat3, p-Stat3, Cyclin D1, and Bcl-x(L) in 45 cases of cancerous tissues, adjacent normal tissues, and two colon cancer cell lines including SW480 and HCT116 was measured by Western blot analysis. The expression pattern of Stat3 and its activated form p-Stat3 was determined by immunohistochemical staining. The relationship of the expression of p-Stat3, Cyclin D1, and Bcl-x(L) in CRC with various clinicopathological characteristics was analyzed statistically. RESULTS: The protein expression rates of p-Stat3, Cyclin D1, and Bcl-x(L) in colorectal cancer and adjacent normal mucosa were 57.8%, 64.4%, 68.9%, and 42.2%, 35.6%, 31.1%,respectively; and their protein levels (A value) were 114263+/-53598, 58321+/-24872, 71032+/-43425 in colorectal cancer and 55971+/-28762, 22563+/-11160, 37281+/-14622 in adjacent normal mucosa (P< 0.05). Overexpression of p-Stat3 was correlated with clinical stage and nodal metastasis in colorectal cancer (P = 0.026 and P= 0.018, respectively). Elevated levels of Cyclin D1 were associated with nodal metastasis (P= 0.041). It was found that Cyclin D1 was in a positive linear correlation fashion with p-Stat3 in tumor (r = 0.382, P< 0.05). Activated Stat3 was also detected in both colon cancer cell lines SW480 and HCT116. CONCLUSION: Stat3 signaling pathway may play an important role in the tumorigenesis of colorectal carcinoma. Determination of Stat3 and its target gene products can be used to indicate the malignancy degree of colorectal carcinoma.