Biomedical subjects

Wenwen Wu

Publications and source records attributed to Wenwen Wu.

15 recordsLinked to original sources

PubMed2006

Protein pattern difference in the colon cancer cell lines examined by two-dimensional differential in-gel electrophoresis and mass spectrometry.

PURPOSE: The pivotal metastatic processes of colorectal cancer (CRC) have yet to be fully investigated by a comprehensive all-inclusive protein analysis. We used two-dimensional differential in-gel electrophoresis (2D-DIGE) and liquid chromatography-tandem mass spectrometry (LC/MS/MS) to investigate the protein pattern changes during the metastasis of CRC. Two CRC cell lines were investigated: SW480 derived from the primary lesion and SW620 derived from lymph node metastasis in the same patient. METHODS: The two cell lines were compared using 2D-DIGE with a maleimide CyDye fluorescent protein labeling technique, which has an enhanced sensitivity for many proteins at a low concentration. A comprehensive proteomics analysis was performed by the dual-labeling method using Cy3 and Cy5 and by LC/MS/MS. In addition, an in vivo experiment of metastasis using nude mice was performed by the injection of the two cell lines into the spleen. RESULTS: Among approximately 1,500 proteins, we detected 9 protein spots with definitively significant changes between the two cell lines. Three out of the nine proteins were validated by a Western blot analysis. Alpha-enolase and triosephosphate isomerase were significantly upregulated in SW620 in comparison to SW480. Annexin A2 (annexin II) was significantly downregulated in SW620 compared to SW480. Neither liver metastasis nor peritoneal dissemination was established in the metastatic experiment using SW480 but some liver and peritoneal metastases occurred in the experiment using SW620. An in vivo metastatic experiment using SW620 showed the expressions of alpha-enolase and triosephosphate isomerase to increase in the liver metastases in comparison to those in the splenic implanted lesion. The expressions of triosephosphate isomerase increased in the peritoneal lesions in comparison to those in the splenic implanted lesion. CONCLUSIONS: 2D-DIGE and LC/MS/MS techniques identified nine proteins that increased significantly more in SW620 than in SW480. The finding of our in vivo metastatic experiment suggests that alpha-enolase and triosephosphate isomerase, at least in part, may be associated with the metastatic process of these two cell lines.

Animals↗

PubMed2006

Chemical radiculitis.

The theory of chemical radiculitis had been put forward about 30 years ago, but as yet it has not been proved by clinical studies. The aim of the current studies was to determine whether the annular tear of a painful disc proved by discography is the cause of radiating leg pain (radiculopathy) in patients with discogenic low back pain. Forty-two patients with discogenic low back pain at single disc level with concomitant radiating leg pain were studied in order to analyse the relationship between site of annular tear and side of radiating leg pain. Electromyogram and motor nerve conduction velocity were monitored to examine nerve root injury. The current studies found that there was a significant positive correlation between the site of annular tear and the side of radiation pain. Abnormalities of electromyogram and reduction of motor nerve conduction velocity were found on the side of radiating leg pain. The studies indicated that leakage of chemical mediators or inflammatory cytokines, which are produced in the painful disc, into epidural space through annular tear could lead to injury to adjacent nerve roots, and it might constitute the primary pathophysiologic mechanism of radiating leg pain in patients with discogenic low back pain but with no disc herniation.

Adult↗

PubMed2006

Possible pathogenesis of painful intervertebral disc degeneration.

STUDY DESIGN: We collected the specimens of lumbar intervertebral disc (i.e., the symptomatic degenerative disc) from patients with discogenic low back pain to study the histopathologic features and growth factor expressions. OBJECTIVES: To study the pathogenesis of disc degeneration, meanwhile discriminating between common disc degeneration (aging disc) (i.e., black asymptomatic disc, not clinically relevant) and painful disc degeneration (i.e., symptomatic disc, clinically relevant). SUMMARY OF BACKGROUND DATA: The pathogenesis of intervertebral disc degeneration is poorly understood, mainly because of the difficulty to establish the experimental model with good reproducibility. Recently, the popularity of spinal fusion leads to more opportunities to obtain disc specimens, which could be applied to explore the pathogenesis of disc degeneration with modern biologic techniques. METHODS: There were 21 specimens of lumbar intervertebral discs from 15 patients with discogenic low back pain during posterior lumbar interbody fusion, 16 aging discs from patients without low back pain, and 10 normal discs as control collected for the study of their histopathologic features, as well as the expressions of basic fibroblast growth factor (bFGF) and its receptor (Flg), transforming growth factor-beta1 (TGF-beta1) and its receptor (TGF-betaRI) by immunohistochemistry. The distribution of macrophages and mast cells was also noted. Proliferating cell nuclear antigen was assessed to evaluate proliferating activities of disc cells. RESULTS: The distinct histologic characteristic of the disc from the patient with discogenic low back pain was the ingrowth of vascularized granulation tissue along torn fissures, extending from the external layer of the anulus fibrosus into the nucleus pulposus. The immunohistochemical staining showed that there were strong expressions of bFGF and TGF-beta1 and their receptors, as well as a strong expression of proliferating cell nuclear antigen in the zones of granulation tissue in the painful discs. However, there were only weak expressions in the nongranulation tissue zones in the painful discs and aging discs, and no expression in the control discs. In addition, abundant macrophages and mast cells were found in the granulation tissue zones of painful discs but absent in the nongranulation tissue zones of painful discs or aging discs and the normal control discs. CONCLUSIONS: The findings indicated that degeneration of the painful disc might originate from the injury and subsequent repair of anulus fibrosus. Growth factors, such as bFGF and TGF-beta1, macrophages and mast cells might play a key role in the repair of the injured anulus fibrosus and subsequent disc degeneration.

Adult↗

PubMed2006

Intradiscal methylene blue injection for the treatment of chronic discogenic low back pain.

This article was a preliminary report of prospective clinical trial of a group of patients with chronic discogenic low back pain who met the criteria for lumbar interbody fusion surgery but were treated instead with an intradiscal injection of methylene blue (MB) for the pain relief. Twenty-four patients with chronic discogenic low back pain underwent diagnostic discography with intradiscal injection of MB. The principal criteria to judge the effectiveness included alleviation of pain, assessed by visual analog scale (VAS), and improvement in disability, as assessed with the Oswestry Disability Index (ODI) for functional recovery. The mean follow-up period was 18.2 months (range 12-23 months). Of the 24 patients, 21 (87%) reported a disappearance or marked alleviation of low back pain, and experienced a definite improvement in physical function. A statistically significant and clinically meaningful improvement in the changes in the ODI and the VAS scores were obtained in the patients with chronic discogenic low back pain (P=0.0001) after the treatment. The study suggests that the injection of MB into the painful disc may be a very effective alternative for the surgical treatment of chronic discogenic low back pain.

Adult↗

PubMed2006

A truncated splice variant of human BARD1 that lacks the RING finger and ankyrin repeats.

BARD1 is a crucial partner of the breast and ovarian tumor suppressor BRCA1 required for ubiquitin ligase activity and for reciprocal stabilization in cells. We report here an alternatively spliced human BARD1 mRNA variant (BARD1DeltaRIN) isolated from a HeLa cell cDNA library. It is characterized by deletion of exons 2-6 that encode most of the RING finger domain and the entire span of ankyrin repeats. DeltaRIN transcript was detected in all breast cancer-cell lines studied although its protein expression level was low. DeltaRIN does not interact with BRCA1, whereas it interacts with and colocalizes with CstF-50 to cytoplasmic dots. Hence, a deletion variant of BARD1 occurs in cells and may play a distinct role with CstF-50.

Amino Acid Sequence↗

PubMed2006

Alternative lengthening of telomeres in the human adrenocortical carcinoma cell line H295R.

Telomere maintenance can occur in the absence of telomerase by a mechanism referred to as alternative lengthening of telomeres (ALT). ALT is considered to be rare in tumors of epithelial origin. The biological significance and molecular mechanism of ALT have not been well studied in human cancers. It has been reported that clinical samples of adrenocortical carcinoma show a low incidence of telomerase positivity. We characterized an adrenocortical carcinoma cell line, H295R, focusing on the telomere maintenance mechanism, and compared it with telomerase-positive 293 cells and HeLa cells. Telomerase activity could not be detected in H295R cells by the TRAP assay. Among the essential components of the telomerase holoenzyme, only hTERT expression was undetectable by RT-PCR, indicating that the lack of telomerase activity is due to suppression of hTERT. H295R cells had long and heterogeneous telomere DNA, and FISH revealed large nuclear bodies in a few interphase nuclei, which presumably represented ALT-associated PML bodies. These results suggest that H295R cells have the ALT phenotype. Several proteins that are possibly associated with the telomere maintenance mechanism were examined. TRF1 and TRF2 were expressed in H295R cells as well as in 293 cells and HeLa cells. The ratio of hnRNP B1 to A2 was higher in H295R cells than in 293 cells and HeLa cells. In conclusion, the H295R adrenocortical carcinoma cell line is negative for telomerase and maintains its telomeres by the ALT mechanism. We anticipate that H295R cells will be a good model for understanding the significance and mechanism of ALT in human cancers.

Adrenal Cortex Neoplasms↗

PubMed2005

The pathogenesis and clinical significance of a high-intensity zone (HIZ) of lumbar intervertebral disc on MR imaging in the patient with discogenic low back pain.

Recently, the presence of a high-intensity zone (HIZ) within the posterior annulus seen on T2-weighted MRI has aroused great interest and even controversy among many investigators, particularly on whether the HIZ was closely associated with a concordant pain response on awake discography. The study attempted to interpret the correlation between the presence of the HIZ on MRI and awake discography, as well as its characteristic pathology. Fifty two patients with low back pain without disc herniation underwent MRI and discography successively. Each disc with HIZ was correlated for an association between the presence of a HIZ and the grading of annular disruption and a concordant pain response. Eleven specimens of lumbar intervertebral discs which contain HIZ in the posterior annulus from 11 patients with discogenic low back pain were harvested for histologic examination to interpret the histologic basis of a nociceptive response during posterior lumbar interbody fusion (PLIF). The study found that in all of 142 discograms in 52 patients, 17 presented HIZ. All 17 discs with HIZ showed painful reproduction and abnormal morphology with annular tears extending either well into or through the outer third of the annulus fibrosus. The consecutive sagittal slices through the HIZ lesion showed that a notable histologic feature of the formation of vascularized granulation tissue in the outer region of the annulus fibrosus. The current study suggests that the HIZ of the lumbar disc on MRI in the patient with low back pain could be considered as a reliable marker of painful outer anular disruption.

Adolescent↗

PubMed2005

Down-regulation of BRCA1-BARD1 ubiquitin ligase by CDK2.

BRCA1, a breast and ovarian tumor suppressor, is a phosphoprotein whose cellular expression level is regulated in a cell cycle-dependent manner. BRCA1 interacts with BARD1 to generate significant ubiquitin ligase activity which catalyzes nontraditional Lys-6-linked polyubiquitin chains. However, it is not clear how the activity is regulated and how this affects BRCA1's multiple cellular functions. Here we show that the ubiquitin ligase activity of BRCA1-BARD1 is down-regulated by CDK2. During the cell cycle, BARD1 expression can largely be categorized into three patterns: moderately expressed in a predominantly unphosphorylated form in early G(1) phase, expressed at low levels in both phosphorylated and unphosphorylated forms during late G(1) and S phases, and highly expressed in its phosphorylated form during mitosis coinciding with BRCA1 expression. CDK2-cyclin A1/E1 and CDK1-cyclin B1 phosphorylate BARD1 on its NH(2) terminus in vivo and in vitro. Intriguingly, the BRCA1-BARD1-mediated in vivo ubiquitination of nucleophosmin/B23 (NPM) and autoubiquitination of BRCA1 are dramatically disrupted by coexpression of CDK2-cyclin A1/E1, but not by CDK1-cyclin B1. The inhibition of ubiquitin ligase activity is not due to the direct effect of the kinases on BARD1 because an unphosphorylatable mutant of BARD1, S148A/S251A/S288A/T299A, is still inhibited by CDK2-cyclin E1. Alternatively, BRCA1 and BARD1 are likely exported to the cytoplasm and their expressions are remarkably reduced by CDK2-cyclin E1 coexpression. Recognizing the importance of cyclin E1 overexpression in breast cancer development, these results suggest a CDK2-BRCA1-NPM pathway that coordinately functions in cell growth and tumor progression pathways.

BRCA1 Protein↗

PubMed2005

Expression of heterogeneous nuclear ribonucleoproteins A2 and b1 in the thyroid follicular cells.

Several proteins implicated in hormonogenesis of the thyroid have alternatively spliced isoforms. Alternative splicing of pre-mRNA is considered to be important to regulate the hormonal activity. Heterogeneous nuclear ribonucleoproteins (hnRNP) A2 and B1 are two of the abundant nuclear RNA-binding proteins involved in alternative splicing. We examined the expression of hnRNP A2 and B1 in the thyroid, paying particular attention to the relationship between their function and the cellular morphology. B1 was expressed more frequently in cuboidal follicular cells that are hormonally active than in flat follicular cells in normal thyroid, although A2 expression showed no significant difference in two cell types. In Graves' disease, the patients who had high serum levels of triiodothyronine and thyroxine showed significantly increased expression of B1. B1 expression did not differ significantly between normal thyroids and thyroid neoplasms, except undifferentiated (anaplastic) carcinoma. Conclusively, B1 expression varied in relation to hormonal activity in thyroid follicular cells. B1 protein is a good immunohistological marker to detect hormonal activity of follicular cells, and may provide a key to elucidate the splicing mechanisms involved in thyroid hormonogenesis.

Alternative Splicing↗

PubMed2004

Nucleophosmin/B23 is a candidate substrate for the BRCA1-BARD1 ubiquitin ligase.

The breast and ovarian tumor suppressor BRCA1 forms a heterodimeric RING-type ubiquitin ligase with BARD1 to catalyze untraditional Lys-6-linked polyubiquitin chains. It is not clear how the BRCA1-BARD1 ligase regulates various cellular processes such as DNA repair, cell-cycle progression, transcriptional regulation, and centrosome duplication. Here we report that BRCA1-BARD1 catalyzes the polyubiquitination of nucleolar phosphoprotein nucleophosmin/B23 (NPM). Two different mass spectrometry screens for protein ubiquitinated by BRCA1-BARD1 both identified NPM. NPM interacts with N-terminal fragments of BRCA1 and BARD1 in a manner dependent upon BRCA1-BARD1 heterodimer formation. NPM colocalizes with BRCA1 and BARD1 in mitotic cells suggesting the possibility of NPM regulation by BRCA1-BARD1 during mitosis. BRCA1-BARD1 catalyzes the ubiquitination of NPM in vitro and in vivo, and BRCA1-BARD1 co-expression in cells causes NPM stabilization rather than degradation. This is consistent with the notion that this ligase catalyzes untraditional polyubiquitin chains. Given the many overlapped functions between NPM and BRCA1, we propose that NPM is a strong candidate as a substrate of the BRCA1-BARD1 ubiquitin ligase.

Animals↗

PubMed2004

Expression and alternative splicing pattern of human telomerase reverse transcriptase in human lung cancer cells.

Telomerase activity is generally considered to be necessary for cancer cells to avoid senescence. The expression of human telomerase reverse transcriptase (hTERT) is believed to be a rate-limiting step in telomerase activation. Recently, it has been proposed that the alternative splicing of hTERT is also involved in regulation of telomerase activity. However, the regulatory mechanism of telomerase in cancer cells has not been thoroughly investigated. To clarify it in lung cancer cells, we measured the expression of the hTERT transcript, analyzed its alternative splicing by RT-PCR, and compared it with telomerase activity and telomere length. The expression of the hTERT transcript was positively correlated with telomerase activity in lung cancer cells. Cancer cells with high telomerase activity contained 4 splicing variants of hTERT, and the full-length variant was 31.3-54.2% of the total transcripts. Cells of the TKB-20 cell line, which has extremely low telomerase activity, showed a different splicing pattern of hTERT in addition to low expression. The functional full-length variant was scarcely detected in TKB-20 cells, suggesting that the telomerase activity was repressed by alternative splicing of hTERT. Telomere length was not necessarily correlated with telomerase activity or hTERT expression in lung cancer cells. Cells of the TKB-4 cell line that also showed relatively low telomerase activity (as TKB-20 cells) had long telomeres. In conclusion, hTERT expression is regulated at both the transcriptional and post-transcriptional levels in lung cancer cells, and the alternative splicing of hTERT is involved in the control of telomerase activity.

Alternative Splicing↗

PubMed2002

Study on characteristics of fractures from road traffic accidents in 306 cases.

OBJECTIVE: To investigate the characteristics of bone fractures from road traffic accidents and analyze their injury mechanisms so as to provide reference for the research and medical care of traffic trauma. METHODS: Three hundred and six patients with fractures from road traffic accidents were included into this study. A total of 507 fractures were identified and the injury mechanism, location distribution and frequency were analyzed. RESULTS: The most common location of fractures was the lower extremities, followed by the upper extremities, skull and maxillofacial region, and the rarest was the spine. A total of 56% of the patients suffered from multiple fractures. The fractures of the patella, femur and pelvis and the fractures of the olecranon, humerus and shoulder often happened simultaneously. CONCLUSIONS: The injury mechanisms can be classified into four types: impact, incoordinate movement, stretch injury and crush and extrusion. The fractures from traffic accidents have the following characteristics: centrifugal distribution of the injuries, multiple fractures, force transmission and ipsilateral occurrence.

Accidents, Traffic↗

PubMed2002

[A monitoring study of electromyography median frequency on fatigue of erector spinalis in drivers working at high altitude].

OBJECTIVE: To evaluate the role of muscle fatigue in the pathogenesis of high prevalence of low back pain(LBP) in drivers who work at high altitude, in order to seek the effective measures for prevention and treatment of LBP. METHOD: The spectral electromyographic(EMG) changes during isometric contraction of erector spinalis to fatigue in 26 drivers in the field were consecutively recorded after daily driving for 5 days. The relationship between the decline of median frequency and the development of the back extensor fatigue were analyzed. RESULTS: The decline rates of EMG median frequency of the erector spinalis on 1-5 working day [(-0.258 +/- 0.087), (-0.248 +/- 0.070), (-0.256 +/- 0.097), (-0.267 +/- 0.093), (-0.274 +/- 0.081)%/s respectively] were significantly different from that of baseline measured before work [(-0.175 +/- 0.114)%/s, P < 0.05 or P < 0.01]. A positive correlation was also found between the decline rate and the working time(r = -0.809, P < 0.05). CONCLUSION: The high prevalence of LBP in the drivers working at high altitude is due to acumulative fatigue of back extensor resulting from long-distance driving, lack of proper rest, decrease of muscle endurance and increase of liability to fatigue, consequently leading to the muscle dysfunction and finally LBP.

Altitude↗

PubMed2002

[Lower back pain in truck drivers working in plateau areas and its prevention].

OBJECTIVE: To investigate the epidemiological characteristics of lower back pain of truck drivers in plateau areas with an analysis of the causes and evaluated the effects of the protective measures. METHODS: The self-reported lower back symptom was investigated by questionnaire in 1,132 male drivers in plateau areas. Vibration of the driver lumbar back was measured real time with or without wearing corset. Study the effect of the special corset for drivers and the massage on back by self-control design of big sample intervention experiments. RESULTS: The prevalence of lower back pain of drivers in plateau areas was 86.1%. High level of its prevalence is due to many factors. Special corset for drivers and massage on back by themselves can reduce the degree of the pain. CONCLUSION: Driving in plateau areas is a special occupational work with high level of prevalence of lower back pain which can be prevented.

Automobile Driving↗

PubMedDate not supplied

The intraductal component of breast cancer is poorly responsive to neo-adjuvant chemotherapy.

Neo-adjuvant chemotherapy has been used for locally advanced breast cancers. With special attention to the proportion of intraductal component, we pathologically studied 25 patients that underwent neo-adjuvant chemotherapy via intra-arterial infusion or intravenous injection. In general, neo-adjuvant chemotherapy had a favorable effect on tumor reduction. The effectiveness varies depending on the predominance of intraductal component. The cases with a high proportion of intraductal component had lower response to the chemotherapies. The larger number of cancer cells remained within the mammary ducts. The residual cancer cells conserved proliferative activity. Intraductal component is poorly responsive to neoadjuvant chemotherapy.

Adult↗