Biomedical subjects

Gang Li

Publications and source records attributed to Gang Li.

At least 163 records · Page 9Linked to original sources

PubMed2004

Growth hormone receptor expression in human colorectal cancer.

The purpose of this study was to determine whether human colorectal cancer (CRC) expresses growth hormone receptor (GHR) and whether growth hormone plays an important role in the development and progression of human CRC. We investigated 42 specimens of CRC and normal colorectal mucous membrane, taken from the colon or rectum in a group of patients with CRC. Immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) technique were used to demonstrate GHR expression. The relationship between expression of GHR and clinical or pathological factors was analyzed. Immunohistochemical analyses revealed that GHR was expressed in human CRC (35/42; 83.33%) and appeared to be up-regulated compared to normal mucous tissue (29/42; 69.05%; P < 0.001). Contrasting sharply with the mostly strongly positive tumors, corresponding normal colorectal mucous membrane was negative or weakly positive. A significant inverse correlation was found between GHR expression and tumor stage (P = 0.002) and tumor differentiation (P = 0.036). In RT-PCR, 33 of the 42 tumors expressed GHR mRNA, while only 22 of the 42 normal colorectal mucous membranes did so. Our data demonstrate that GHR is frequently expressed in human CRCs and appears to be up-regulated compared to normal mucous tissue, thus supporting a possible role for growth hormone in CRC physiology.

Adenocarcinoma↗

PubMed2004

Baerveldt-350 implant versus Ahmed valve for refractory glaucoma: a case-controlled comparison.

PURPOSE: To compare the efficacy of intraocular pressure (IOP) control of the Baerveldt-350 implant with tube ligature and the Ahmed valve in patients with refractory glaucoma. PATIENTS AND METHODS: Four hundred seventy glaucoma drainage device procedures from July 1995 to July 2001 (6 years) were reviewed retrospectively. Thirty-two cases of Baerveldt-350 implantation performed in patients with glaucoma refractory to medical treatment and filtering procedures, without previous drainage device or cyclodestructive procedures, and with a minimum of 1-year follow-up were identified. Thirty-two cases of Ahmed valve implantation were matched case by case with 32 Baerveldt-350 cases for age, race, gender, glaucoma subtype, previous ocular history, preoperative IOP, and surgeon who performed the implantation. The two groups were compared for IOP control, visual outcome, complication rate, and surgical success rate. Surgical success rate was defined as an IOP reduction greater than or equal to 30% and final IOP more than 5 mm Hg and less than 22 mm Hg, without devastating complications. RESULTS: Over a follow-up period of 1 year, no statistically significant differences were detected between the Baerveldt-350 implant versus Ahmed valve for IOP control (12.1 +/- 5.3 mm Hg vs. 13.6 +/- 5.6 mm Hg respectively, at a power of 90% to detect a difference of 3.2 mm Hg between the two groups and P = 0.05), surgical success rate (65.6% vs. 65.6% respectively, complete and qualified combined), postoperative hypotony rate (37.5% vs. 34.4% respectively), and visual acuity changes of more than 1 line in Snellen visual acuity (43.3% vs. 29.0% respectively). CONCLUSION: In a case-controlled comparison, the Baerveldt-350 implant and the Ahmed valve had similar IOP control and surgical outcomes in patients with refractory glaucoma at 1-year follow-up.

Adult↗

PubMed2004

XAF1 expression is significantly reduced in human melanoma.

Deregulation of apoptotic processes is likely one of the key factors contributing to the malignant nature of melanoma marked by strong chemoresistance. X-linked inhibitor of apoptosis protein (XIAP) suppresses apoptosis through the inhibition of various caspases. Recently, XIAP-associated factor 1 (XAF1) has been identified as a XIAP-binding protein that antagonizes the anti-apoptotic activity of XIAP. In this study, we sought to determine the role of XAF1 in melanoma progression. Analysis of XAF1 mRNA expression in melanoma cell lines revealed that XAF1 mRNA was downregulated in 15 of 16 cell lines examined. We next evaluated XAF1 protein expression on a tissue microarray representing 40 benign nevi and 70 primary melanomas. Our results showed that XAF1 expression in melanoma tissues was significantly reduced compared with benign melanocytic nevi (p<0.05). Our data also demonstrated that the substantial reduction of XAF1 expression occurred in both nucleus and cytoplasm in the tumor cells (p<0.0001 for both). Reduced XAF1 expression, however, was not significantly correlated with tumor thickness and 5-y patient survival. Further studies are required to understand the molecular mechanisms governing the selective loss of XAF1 expression in the tumor tissue.

Adaptor Proteins, Signal Transducing↗

PubMed2004

Regulation of telomere length and suppression of genomic instability in human somatic cells by Ku86.

Ku86 plays a key role in nonhomologous end joining in organisms as evolutionarily disparate as bacteria and humans. In eukaryotic cells, Ku86 has also been implicated in the regulation of telomere length although the effect of Ku86 mutations varies considerably between species. Indeed, telomeres either shorten significantly, shorten slightly, remain unchanged, or lengthen significantly in budding yeast, fission yeast, chicken cells, or plants, respectively, that are null for Ku86 expression. Thus, it has been unclear which model system is most relevant for humans. We demonstrate here that the functional inactivation of even a single allele of Ku86 in human somatic cells results in profound telomere loss, which is accompanied by an increase in chromosomal fusions, translocations, and genomic instability. Together, these experiments demonstrate that Ku86, separate from its role in nonhomologous end joining, performs the additional function in human somatic cells of suppressing genomic instability through the regulation of telomere length.

Antigens, Nuclear↗

PubMed2004

Rh2, a compound extracted from ginseng, hypersensitizes multidrug-resistant tumor cells to chemotherapy.

Rh2 is a ginsenoside extracted from ginseng that has drawn attention in a few laboratories in Asian countries because of its potential tumor-inhibitory effect. In the present study, we tested Rh2 on many tumor-cell lines for its effects on cell proliferation, induction of apoptosis, and potential interaction with conventional chemotherapy agents. Our results showed that Rh2 inhibited cell growth by G1 arrest at low concentrations and induced apoptosis at high concentrations in a variety of tumor-cell lines, possibly through activation of caspases. The growth arrest and apoptosis may be mediated by 2 separate mechanisms. Apoptosis is not dependent on expression of the wild-type p53 nor the caspase 3. In addition, the apoptosis induced by Rh2 was mediated through glucocorticoid receptors. Most interestingly, Rh2 can act either additively or synergistically with chemotherapy drugs on cancer cells. Particularly, it hypersensitized multidrug-resistant breast cancer cells to paclitaxel. These results suggest that Rh2 possesses strong tumor-inhibiting properties, and potentially can be used in treatments for multidrug-resistant cancers, especially when it is used in combination with conventional chemotherapy agents.

Animals↗

PubMed2004

[The prevalence analysis of cleft palate in Chinese perinatals: 1996-2000].

OBJECTIVE: To study the epidemiological features of cleft palate (CP) in Chinese perinatals. METHODS: Data from 1996 to 2000 were collected through Chinese Birth Defects Monitoring Network a hospital based congenital malformation registry system. During that period all live or still births with 28 weeks of gestation or more were assessed within 7 days after delivery. RESULTS: 499 perinatals with CP were identified among 2,218,616 births, then the overall prevalence rates of CP were 2.25/10,000, rates in isolated and syndromic CP were 1.75/10,000, 0.50/10,000 respectively. The rates in urban and rural area, in male and female births were 2.27/10,000 and 2.19/10,000, 1.93/10,000 and 2.57/10,000 respectively. The highest but nonsignificant rate (2.84/10,000) was found in maternal age group of more than 35 years. An increased trend was found both in overall CP and syndromic CP during that period. Geographic variation was found among provinces. The perinatal mortality rate of CP was 14.9%, and the rate of isolated forms was 7.3%, while the rate of syndromic CP was as high as 41.4%. CONCLUSION: The increasing prevalence rate of syndromic CP can account for the secular trend of overall CP. Female predominance was only observed in isolated forms of CP among Chinese perinatals. Geographic variation was identified too. Due to poor birth quality, perinatals suffering from syndromic CP had poor prognosis.

Adult↗

PubMed2004

[A pilot study on the culture and differentiation of bone marrow stromal cells from SD rats].

In order to observe the growth, expansion and differentiation of the cultured bone marrow stromal cells (BMSC), we isolated the BMSC from adult SD rats and cultivated them with LIF and bFGF. Then, we cultured and induced the stem cells by using retinoic acid and the culture medium confected in our lab by ourselves. We found that the BMSC could expand and generate clones when they were cultured in vitro. These cells subcultured grew rapidly and differentiated into neuron-like cells and astrocyte-like cells. The results showed that BMSC have the abilities to self renew and differentiate, thus demonstrating the culture method we used is suitable for the culture of BMSC in vitro. The bone marrow stromal cell is not difficult to obtain; it is capable of expanding and differentiating in culture. If the culture condition is appropriate, it can differentiate into neuron and astrocyte. So, it is a kind of perfect seed cells.

Actihaemyl↗

PubMed2004

Effect of inhibition of EBV-encoded latent membrane protein-1 by small interfering RNA on EBV-positive nasopharyngeal carcinoma cell growth.

OBJECTIVE: To evaluate the feasibility of using small interfering RNA (siRNA) for selective inhibiting latent membrane protein-1 (LMP1) expression in Epstein-Barr virus (EBV)-positive nasopharyngeal carcinoma (NPC) cell line C611, and observe the effects of LMP1 gene silencing on the NPC cell growth. METHODS: Four synthesized double-strand siRNA were respectively transfected into NPC cells, using Oligofectamine reagent. The subsequent changes in LMP1 mRNA level were determined by semi-quantitative reverse transcriptase (RT)-PCR. Flow cytometry and MTT assay were employed to examine the alterations in cell cycle and cell proliferation. RESULTS: The most effective sequence was identified among the 4 candidate siRNAs, and its single dose caused nearly 90% loss of LMP1 mRNA in C611 cells, with sustained specific inhibition for 96 h following a re-transfection. LMP1 siRNA treatment resulted in cell cycle arrest at G(0)-G(1) phase, accompanied by a reduction of cell proliferation by 33%, whereas EBV-negative NPC cells appeared unaffected. CONCLUSIONS: EBV-encoded LMP-1 is vulnerable to RNA interference and selective inhibition of LMP1 suppresses the proliferation of EBV-positive NPC cells, a finding that sheds light on the possible use of RNA interference in further investigations of LMP1 and for therapeutic purposes of EBV-related NPC.

Apoptosis↗

PubMed2004

[Clinical analysis of 31 cases of traumatic interhemispheric subdural hematomas].

OBJECTIVE: To analyze the clinical characteristics, pathogenesis and management of traumatic interhemispheric subdural hematomas (ISH). METHODS: Thirty-one traumatic ISH cases were reviewed and analyzed retrospectively. RESULTS: Of the 31 patients, 29 were cured and 2 died of multi-system organ failure (MSOF) and cerebral hernia respectively. Typically, ISH manifested hemiplegia or paralysis of the counterlateral lower limb known as falx syndrome. CONCLUSIONS: CT scans showing hematocele in the interhemispheric subdural space in excess of 20 ml, or with a thickness of hematocele over 1cm, may serve as a diagnostic criteria for ISH. For the treatment of ISH, surgery and conservative management are suggested on the basis of functional disturbance or the stability of the disease.

Adolescent↗

PubMed2004

[The mRNA expression of platelet-derived endothelial cell growth factor of bladder transitional cell carcinoma and its relation to invasiveness].

OBJECTIVE: To investigate the relationship between mRNA expression of platelet-derived endothelial cell growth factor (PD-ECGF) and invasion of bladder transitional cell carcinoma (BTCC). METHODS: The mRNA expression of PD-ECGF in BTCC was detected by RT-PCR. The target PCR bands were analyzed by NIH Image 1.62 software. RESULTS: The mRNA level of PD-ECGF in BTCC was 3.86 times as high as that of normal bladder mucosa (t = 2.36, P < 0.05). The expression level of stage Ta, T1 and T2-4 tumor was 1.33, 4.02 and 7.59 times as high as that of normal bladder mucosa, respectively. That of Grade 3 tumor was 2.27 times as high as that of Grade 1 - 2 tumor (t = 3.52, P < 0.01). CONCLUSION: The mRNA expression of PD-ECGF was positively correlated with the invasiveness and grade of BTCC. The results suggest that the mRNA level of PD-ECGF might be used as an indicator of tumor progression and a guide for clinical treatment of bladder transitional cell carcinoma.

Adult↗

PubMed2004

[Effect of para-aminobenzonic acid (PABA) on cell-surface hydrophobicity of Streptococcus mutans].

OBJECTIVE: To study the effect of Para-aminobenzonic acid on cell-surface hydrophobicity of Streptococcus mutans. METHODS: Microbial adhesion to hydrocarbons (MATH) was used to measure the cell-surface hydrophobicity of Streptococcus mutans which grew in modified Carlsson medium with different dilutions of PABA. RESULTS: The cell-surface hydrophobicity of Streptococcus mutans increased when Carlsson medium contained low dilution of PABA. But following the increase of PABA, the cell-surface hydrophobicity decreased. CONCLUSION: Para-aminobenzonic acid could inhibit the adherence of Streptococcus mutans through changing its cell-surface hydrophobicity.

4-Aminobenzoic Acid↗

PubMed2004

Mutations of the ING1 tumor suppressor gene detected in human melanoma abrogate nucleotide excision repair.

Epidemiological evidence indicates that ultraviolet radiation (UVR) is the primary environmental cause of the rapid increase in the incidence of human cutaneous melanoma observed in the past decades. However, the genetic changes caused by UVR that lead to melanoma formation remain unclear. The ING1 (inhibitor of growth 1) tumor suppressor plays an important role in cellular stress response to UVR. To further investigate whether ING1 is involved in melanoma development, we examined the mutational status of the ING1 gene in 46 human cutaneous melanoma biopsies and characterized the biological importance of ING1 mutations in nucleotide excision repair. Single-strand conformation polymorphism and DNA sequencing were used to detect the mutational status of the ING1 gene. The host-cell-reactivation assay and radioimmunoassay were used to determine the role of ING1 mutations in nucleotide excision repair. We show that 20% of the melanoma primaries contained missense mutations in the SAP30-interacting domain and PHD finger motif of the ING1 gene with the R102L and N260S alterations observed more than once. Furthermore, our data indicate that patients that harbor ING1 mutations in the tumors have a higher risk to die from the disease within 5 years (50%) compared to patients with no ING1 mutation (18%). Moreover, we demonstrated that mutations at codon 102 or 260 as well as deletion of the PHD finger motif are detrimental to p33ING1-mediated enhancement of DNA repair. Taken together, our data indicate that ING1 mutations abrogate its enhancement in nucleotide excision repair.

Amino Acid Substitution↗

PubMed2004

[Designing dental manpower index to evaluate dental manpower resources].

OBJECTIVE: The purpose of this investigation is to find out a method to evaluate dental manpower resources. METHODS: We selected population, GDP, number of dentist and number of different oral health professionals from certain internet stations, published books and journals from 1996 to 2000 as our investigating data. RESULTS: Data was collected from 100 countries. Our investigation found that the design of dental manpower index to evaluate dental manpower resources was effective and convenient. CONCLUSION: Dental manpower index is a good method to evaluate dental manpower resources.

Dental Assistants↗

PubMed2004

Traumatic subdural hydroma developing into chronic subdural hematoma.

OBJECTIVE: To probe the incidence, pathogenesis and clinical characteristics of traumatic subdural hydroma (TSH) developing into chronic subdural hematoma (CSDH). METHODS: We retrospectively analyzed the clinical data of 32 patients with TSH developing into CSDH and reviewed related literature. RESULTS: 16.7% of TSH developed into CSDH in this study. The time of evolution was from 22 to 100 days after head injury. All the patients were cured with hematoma drainage. CONCLUSIONS: TSH is one of the origins of CSDH. The clinical characteristics of TSH developing into CSDH follow that the ages of the patients are polarized, that the evolution often happens in the patients with small chronic hydromas and being treated conservatively, that the patients are usually injured deceleratedly and that the accompanying cerebral damage is often very mild.

Adolescent↗

PubMed2004

[Enhancement effect of interferon gamma on the sensitivity of RT4 bladder cancer cells to 5'-deoxy-5-fluorouridine,and 5-fluorouracil through up-regulation of PD-ECGF/TP].

BACKGROUND & OBJECTIVE: Platelet-derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/TP) is an essential enzyme in converting 5'-deoxy-5-fluorouridine (5'-DFUR), and 5-fluorouracil (5-FU) to their active metabolites in vivo, and can be up-regulated by some cytokines such as interleukin-1, and interferon gamma (INFgamma). This study was to observe the regulative effect of INFgamma on expression of PD-ECGF/TP, and its relation with the anti-cancer effect of 5'-DFUR, and 5-FU on RT4 bladder cancer cells. METHODS: PD-ECGF/TP mRNA, and protein expression were determined by reverse transcriptase polymerase chain reaction (RT-PCR), and Western blot analysis, respectively. Cytotoxicity of 5'-DFUR, and 5-FU against RT4 cells was evaluated by 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymetho-xyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay. RESULTS: Expression levels of PD-ECGF/TP mRNA and protein were elevated in RT4 cells after cultured with INFgamma. INFgamma reduced IC50s of 5'-DFUR [from (9.7+/-0.2) mmol/L to (3.7+/-0.9) mmol/L], and 5-FU [from (130.0+/-21.2) mmol/L to (49.3+/-18.4) mmol/L] in RT4 cells. CONCLUSIONS: INFgamma enhances cytotoxicity of 5'-DFUR, and 5-FU against RT4 cells through induction of PD-ECGF/TP. INFgamma/5'-DFUR or INFgamma/5-FU combination treatment may lead to better chemotherapeutic results in human bladder cancer.

Antineoplastic Agents↗

PubMed2004

[Therapeutic effect of infrared radiation on skin scald in rats].

OBJECTIVE: To investigate the therapeutic effect of infrared radiation (IR) on the skin scald in rats. METHODS: Thirty-nine male Wistar rats were used in the study, and they were randomly divided into normal control (C, n = 13), scald (S, n = 13, no treatment after scalding) and treatment (T, n = 13, with IR radiation treatment for 5 days since 2nd post scalding day (PSD) groups. The rats in S and T groups were subjected to deep partial thickness scalding on the back. The cutaneous tissue samples from rat wound in each group were harvested on the 3rd and 7th PSD for pathomorphological examination. DNA synthesis in wound tissue was analyzed by 3H-TdR incorporation method, and the vascular permeability in cutaneous tissue, degree of tissue edema and MDA content were determined by corresponding methods. RESULTS: Epidermal exfoliation, cutaneous ulcer, follicular atrophy and damage, and massive formation of collagen were identified in the skin wound of rats in S group on the 7th PSD compared with C group. The skin in T group was smooth with slight atrophy and a few collagen fibers in follicles. The 3H-TdR incorporation amount in the rats in T group (1856.33 +/- 343.81 cpm/mg) on the 7th PSD was significantly higher than that in S group (1353.95 +/- 274.48 cpm/mg) (P < 0.01). The tissue permeability, edema degree and MDA content in the cutaneous tissue in S group were obviously higher than those in group C, while these indices were markedly lower in T group when compared with those in S group (P < 0.01-0.001). CONCLUSION: Treatment with IR seemed to be beneficial to the promotion of skin tissue metabolism and tissue repair.

Animals↗

PubMed2004

[Establishment of an animal model of human hyperplastic scar in nude mice].

OBJECTIVE: To establish an ideal model of human hyperplastic scar (HS) in nude mice, so as to provide us a new model to carry out further studies on the mechanism of HS development. METHODS: Full skin defect sized 2.0 cm x 1.5 cm was created on the back of 100 nude mice. The defect was thereafter covered with full thickness human skin. After the grafted skin survived, the nude mice were subjected to deep partial thickness burn of the grafted skin with heated copper rod. The development of the hyperplasia of the scar after wound healing was observed histologically and grossly. RESULTS: Grafted full-thickness human skin took and survived well in 86 out of 100 nude mice. There was obvious and continuous hyperplasia of scar in 67 mice (78%). The external appearance and histological features of the HS appeared similar to those in human HS. The average thickness of the scar was 0.34 cm, with the thickest part measuring 0.6 cm. In addition, the time of hyperplastic change lasted for 63 - 217 days in average of 128 days. CONCLUSION: Obvious and continuous scar hyperplasia could be found in this model, and the whole process beginning from wound healing to the formation of HS could be easily observed. The model was therefore suitable and ideal for the study of HS.

Animals↗

PubMed2004

[Study on the expression of nm23-M1/NDPK a during the blastocyst adhesiveness in the mouse endometrium].

The nm23 gene was originally identified as a metastasis suppressor gene by differential hybridization of non-metastatic and metastatic clones of murine K-1735 melanoma cell lines. Subsequently, other highly homologous genes were characterized and shown to code for nucleoside diphosphate kinase (NDPK) isotypes. These enzymes have been evidenced in a wide variety of organisms. In human, up to eight distinct but highly related genes have been discovered. The nm23-H1 and nm23-H2 gene products share 88% identity and are about 95% and 98% identical to the murine nm23-M1 and nm23-M2 proteins respectively. A number of data indicate that nm23 family, initially documented as metastasis suppressors in some cancer types, are involved in the control of normal development, differentiation and apoptosis. The trophoblast cells of blastocyst and of the normal first-trimester placenta share some phenotypic similarities with malignant cells, such as rapid proliferation and ability to invade neighbouring tissues, including basement membrane, during the process of implantation and placental development, but do not have the ability for unlimited growth or metastasis, as few trophoblast cells can be identified in the deciduas, and trophoblasts rarely penetrate the maternal blood vessels. Although some data indicate that nm23 family play an important role in regulation of reproductive processes, little is know about its actual mechanism. In our studies, we performed RT-PCR, Western blot and immunohistochemical analyses of nm23-M1/NDPK A expression during the blastocyst adhesiveness in the mouse endometrium. The nm23-M1 mRNA expression was shown progressive increase in D5 mice endometrium by RT-PCR, which was consistent with the result obtained by Western blot and immunohistochemistry. It is suggested that nm23-M1/NDPK A was involved in the process of blastocyst implantation.

Animals↗