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Biomedical subjects

Min Xu

Publications and source records attributed to Min Xu.

At least 109 records · Page 6Linked to original sources
PubMed2004

Hypermethylation of the RASSF1A gene in gliomas.

BACKGROUND: Promoter methylation is an important pathway in transcriptional silencing of tumor suppressor genes (TSGs) in brain tumors. The identified 3p21.3 tumor suppressor gene RAS association domain family protein 1A (RASSF1A) is highly methylated in primary lung, breast and other tumors. We investigated the promoter methylation and gene expression of RASSF1A in gliomas. METHODS: The methylation status of the promoter region of RASSF1A, p16INK4A and death-associated protein kinase (DAPK) genes was analyzed by methylation-specific PCR (MSP) in 41 surgically resected gliomas. RASSF1A expression was also detected by reverse-transcription polymerase chain reaction (RT-PCR) in 28 glioma tissues. RESULTS: The frequencies of RASSF1A, p16INK4A and DAPK promoter methylation were 13/41 (31.7%), 3/41 (7.3%) and 6/41 (14.6%) respectively. However, the methylations of those genes were not correlated with the clinical characteristics of patients (tumor grade, tumor types and sex). Among 28 glioma tissues, 6 showed the loss of the gene (21.4%). Promoter hypermethylation of RASSF1A is associated with loss of gene expression in glioma tissues. (p=0.022). CONCLUSIONS: Our results suggested that the RASSF1A gene might play an important role in glioma carcinogenesis. It also gives us an insight for future glioma medical therapy with a demethylating agent.

Adolescent↗
PubMed2004

Quality and safety issues of web-based information about herbal medicines in the treatment of cancer.

A number of studies have been carried out to assess health information on the internet and they all have demonstrated that, whereas the internet can be the third opinion for many patients, often contains inaccurate and misleading information. Furthermore, as herbal medicines are increasingly used by patients, it is imperative to assess the quality of information presented on the internet. Hence, the aim of this study was to assess the quality and safety of the information presented on the internet about medicinal herbs specifically in the field of cancer. Two hundred relevant websites were initially selected from a process using 10 search engines and the keywords 'herbs' and 'cancer', and 43 sites actually met all inclusion criteria. Assessment of both quality and safety indicators was carried out using the DISCERN instrument, which has been developed to enable consumers and information providers to judge the quality of health information. Readability scores of the sites were also obtained (Flesch formula). It was shown that most sites had low quality in a number of indicators, including accuracy of information, revealing sources of information, biased presentation of information or regularity of updates. The mean score for quality was 22.12 (S.D.=4.18) out of a maximum score of 50. The mean safety score was 13.26 (S.D.=2.14) out of a maximum score of 30. Commercial sites had the most inaccurate or misleading information, emphasizing only the positive aspects of the use of herbs, with little or no evidence. The only biomedical sites assessed achieved the highest score in both quality and safety. Readability of the information was equal to the school level of college (mean=44.63). Seven percent of the sites discouraged the use of conventional medicine. Results suggest that health professionals should talk about use of alternative therapies with their patients and help them find the best available information when using the internet.

Cross-Sectional Studies↗
PubMed2004

Expression of a novel DnaJA1 alternative splicing in human testis and sperm.

Using cDNA microarray hybridization from a human testicular cDNA library, one gene exhibiting threefold difference at expression level between adult and embryo human testes was named nDnaJA1 (a new alternative isoform of human DnaJA1 which was also named HDJ2/Hsdj/dj2, a human HSP40 homologue), which was believed to be involved in testis development and spermatogenesis. Multiple tissue polymerase chain reaction (PCR) results showed that nDnaJA1 expressed highly in testis and lung but low in thymus, prostate, colon and liver. The results of the other members of DnaJA1 family (GenBank accession numbers: D13388 and BC008182) showed that they were widely expressed. D13388 and BC008182 were highly expressed in sperm while nDnaJA1 was faintly expressed by reverse transcriptase PCR. Protein motif analysis of nDnaJA1 sequence revealed motifs of DnaJ. nDnaJA1 was considered as type I DnaJ like the other members of DnaJA1 family.

Alternative Splicing↗
PubMed2004

Innate immune responses in peptidoglycan recognition protein L-deficient mice.

Peptidoglycan recognition proteins (PGRPs) constitute a family of innate immune recognition molecules. In Drosophila, distinct PGRPs bind to peptidoglycans on gram-positive or gram-negative bacteria and provide essential signals upstream of the Toll and Imd pathways required for immunity against infection. Four PGRPs, PGRP-L, -S, -Ialpha, and -Ibeta, are expressed from three genes in mammals. In this paper, we provide direct evidence that the longest family member, PGRP-L, is a secreted serum protein with the capacity to multimerize. Using gene targeting to create PGRP-L-deficient mice, we demonstrate little contribution by PGRP-L to systemic challenge using gram-negative bacteria (Escherichia coli, slightly less susceptible), Gram-positive bacteria (Staphylococcus aureus), or yeast (Candida albicans). Peritoneal macrophages from PGRP-L-deficient mice produced decreased amounts of the inflammatory cytokines interleukin 6 and tumor necrosis factor alpha when stimulated with E. coli or lipopolysaccharide, but comparable amounts when stimulated with S. aureus, C. albicans, or their cell wall components. Additionally, these cells produced similar amounts of cytokines when challenged with gram-positive or -negative peptidoglycans. In contrast to its critical role in immunity in flies, PGRP-L is largely dispensable for mammalian immunity against bacteria and fungi.

Animals↗
PubMed2004

Notch-induced E2A degradation requires CHIP and Hsc70 as novel facilitators of ubiquitination.

E2A transcription factors, E12 and E47, are important regulators of lymphocyte development. Notch signaling pathways have been shown to regulate E2A function by accelerating the degradation of E2A proteins through a mitogen-activated protein kinase-dependent and ubiquitin-mediated pathway. To further understand the mechanism underlying E2A ubiquitination and degradation, we conducted a yeast two-hybrid screen and identified the carboxyl terminus of Hsc70-interacting protein (CHIP) as an E47 binding protein. Here, we show that CHIP associates with E2A proteins in vivo and that overexpression of CHIP induces E47 degradation in a phosphorylation-dependent manner. Conversely, knocking down CHIP with small interfering RNA alleviates Notch-induced E47 degradation. CHIP binds E47 through the E protein homology domains 2 and 3 (EHD2 and EHD3). This interaction between CHIP and E47 is independent of the U-box domain with E3 ubiquitin ligase activity but requires the chaperone binding tetratricopeptide repeats domain. The ability of CHIP to induce E47 ubiquitination and degradation correlates with its ability to bind E47. We propose that CHIP, together with its partner Hsc70, forms a preubiquitination complex (PUC) with E47 and Skp2, thus facilitating the interaction between E47 and Skp2. CHIP also associates with Cul1, which introduces PUC to the SCF E3 ligase complex, responsible for E47 ubiquitination. Therefore, CHIP plays a crucial role in the ubiquitination and degradation of E2A proteins.

Amino Acid Sequence↗
PubMed2004

Cloning and expression of a novel CREB mRNA splice variant in human testis.

Identification of genes specifically expressed in adult and fetal testis is important in furthering our understanding of testis development and function. In this study, a novel human transcript, designated human testis cAMP-responsive element-binding protein (htCREB), was identified by hybridization of adult and fetal human testis cDNA probes with a human cDNA microarray containing 9216 clones. The htCREB transcript (GenBank Accession no. AY347527) was expressed at 2.35-fold higher levels in adult human testes than in fetal testes. Sequence and ntBLAST analyses against the human genome database indicated that htCREB was a novel splice variant of human CREB. RT-PCR-based tissue distribution experiments demonstrated that the htCREB transcript was highly expressed in adult human testis and in healthy sperm, but not in testes from patients with Sertoli cell-only syndrome. Taken together, these results suggest that the htCREB transcript is chiefly expressed in germ cells and is most likely involved in spermatogenesis.

Alternative Splicing↗
PubMed2004

Characterization of enhancer trap and gene trap harboring Ac/Ds transposon in transgenic rice.

Insertion mutagenesis has become one of the most popular methods for gene functions analysis. Here we report a two-element Ac/Ds transposon system containing enhancer trap and gene trap for gene tagging in rice. The excision of Ds element was examined by PCR amplification. The excision frequency of Ds element varied from 0% to 40% among 20 F(2) populations derived from 11 different Ds parents. Southern blot analysis revealed that more than 70% of excised Ds elements reinserted into rice genome and above 70% of the reinserted Ds elements were located at different positions of the chromosome in rice. The result of histochemical GUS analysis indicated that 28% of enhancer trap and 22% of gene trap tagging plants displayed GUS activity in leaves, roots, flowers or seeds. The GUS positive lines will be useful for identifying gene function in rice.

Base Sequence↗
PubMed2004

The molecular characteristics of polycystic ovary syndrome (PCOS) ovary defined by human ovary cDNA microarray.

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders; it is characterized by polycystic ovaries, hyperandrogenism and chronic anovulation. To obtain a global view of those genes that might be involved in the development of this complex clinical disorder, we used recently developed cDNA microarray technology to compare differential gene expressions between normal human ovary and ovaries from PCOS patients. A total of 9216 clones randomly selected from a commercial human ovary cDNA library were screened. Among them, 290 clones showed differential expressions, including 119 known genes and 100 known or unknown expressed sequence tags (ESTs). Among 119 known genes, 88 were upregulated and 31 downregulated in the PCOS ovary, as compared with normal human ovary. These differentially expressed genes are involved in various biologic functions, such as cell division/apoptosis, regulation of gene expression and metabolism, reflecting the complexity of clinical manifestations of PCOS. The molecular characteristics established from our study will further our understanding of the pathogenesis of PCOS and help us to identify new targets for further studies and for the development of new therapeutic interventions.

Base Sequence↗
PubMed2004

[Osteogenesis characteristics of cultured rat mesenchymal stem cells under bone induction condition].

OBJECTIVE: To investigate the osteogenesis characteristics of cultured rat mesenchymal stem cells (MSCs) under bone induction condition. METHODS: MSCs were isolated from adult rat by using density gradient separation method. The osteogenic inducers were compounds of Dexone, beta-glycerophosphate sodium and vitamin C. RESULTS: The MSC attachment formed soon after the seeding and grew into colonies with the appearance of fibroblastic cells. The osteogenic inducer with low dose of Dexone could promote the osteogenic differentiation of MSC. In the group of osteogenic inducer with low dose of Dexone, the expression of alkaline phosphatase (ALP) was remarkably increased after one week's induction, and the number of positive cells was (15.1 +/- 2.6), significantly higher than that of the control group (12.0 +/- 3.5) (P < 0.01). The calcified deposits began to appear in the group of osteogenic inducer with low dose of Dexone after one week's induction and was increased remarkably after three weeks, and the number of calcified deposits was (9.0 +/- 1.7), significantly higher than that of the control group (2.0 +/- 1.8) (P < 0.01). CONCLUSION: MSC can differentiate into osteogenesis by osteogenic induction and may be used to provide seed cells for bone tissue engineering.

Alkaline Phosphatase↗
PubMed2004

Flow cytometric validation of automated differentials in pediatric patients.

Manual differential white blood cell (WBC) counting has been considered the gold standard and is routinely used to validate differentials obtained with other methodologies. To validate the accuracy of automated lymphocyte counts, we compared 2-part differentials using a Coulter HmX hematology analyzer and a Coulter XL flow cytometer to analyze 57 pediatric samples with WBC counts ranging from 0.7 k to 33.4 k. These data were compared with manual differential counts. We found excellent correlation between the two automated lymphocyte and monocyte counting methods that surpassed the manual correlations, indicating manual lymphocyte or monocyte counts are unnecessary in the setting of quality scatterplots. To evaluate the use of automated differentials for our most labor-intensive cases (low WBCs, which frequently require manual differentials) we then compared 3-part differentials using the HmX hematology analyzer and flow cytometer for 51 samples with total WBC < or = 1.1 x 10(9)/L. Manual differentials (< or = 100-cell counts) were available on 27 samples. Although the correlations for manual versus automated or flow differentials were good for all cell types, the correlation between the two automated methods was better, irrespective of the hematology analyzer scatterplot quality. Preliminary data provide additional evidence that automated differentials in samples with WBC of < or = 1.1 x 10(9)/L are acceptable for reporting, thus saving technologist time and improving patient care by decreasing the resulting turnaround time. These studies suggest that comparison with a standardized procedure like flow cytometry would be a better method for validation of automated differentials than comparison with the less precise, more laborious manual differential.

Autoanalysis↗
PubMed2004

[Postoperative intraperitioneal hyperthermic chemoperfusion combined with intravenous chemotherapy for 82 advanced gastric cancer patients].

OBJECTIVE: To evaluate the efficacy of postoperative intraperitoneal hyperthermic chemoperfusion (IHCP) combined with intravenous chemotherapy for advanced gastric cancer. METHODS: Eighty-two patients with stage II - IV gastric cancer were postoperatively randomized into two groups; 46 patients in treatment group who received IHCP combined with intravenous chemotherapy for three times and 36 patients in control group who received intravenous chemotherapy only for six times. All patients in the two groups received the same chemo-regimen LFAP (CF + 5-Fu + THP or MIT + PDD) 21 - 28 days after operation. RESULTS: The 1-year survival rate was 98% (45/46) in the treatment group and 94% (34/36) in the control group without any significant difference (P > 0.05). The 3-year survival rate was 83% (38/46) in the treatment group and 61% (22/36) in the control group with significant difference (P < 0.05). Gastrointestinal reaction in the treatment group was significantly decreased compared with in the control group (37% vs 80%, P < 0.01), whereas no statistically significant difference was noted in bone marrow suppression (P > 0.05). CONCLUSION: Intraperitoneal hyperthermic chemoperfusion combined with intravenous chemotherapy can prolong survival and reduce gastrointestinal side-effect which provides an effective treatment option for advanced gastric cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

[Clinical significance of serum transferrin receptor in differential diagnosis of anemia].

OBJECTIVE: To study the clinical significance of the serum transferrin receptor (sTfR) and ferritin in distinguishing between iron deficiency anemia (IDA), anemia of chronic disease (ACD) and ACD with complicating IDA (ACD-IDA). METHODS: One hundred and thirteen subjects enrolled into the study were divided into four groups including 28 health volunteers as control, 29 patients with IDA, 27 patients with ACD (sTfR level 20.0 nmol/L, ACD2 group). sTfR, serum ferritin (SF), serum iron (SI), total iron-binding capacity (TIBC), transferring saturation (TS) and complete blood count were measured in all the enrolled subjects or patients. Bone marrow iron stain was examined in 10 cases of ACD1 and 16 cases of ADC2. RESULTS: In IDA group, MCV (68.0 +/- 11.3) fl was the smallest; SI, TS and SF were significantly decreased but sTfR level was increased as compared with the control group (SI) (19.6 +/- 10.1) mg/L vs (81.7 +/- 30.6) mg/L, TS (5.5 +/- 2.3)% vs (27.0 +/- 12.0)%, SF (4.3 +/- 2.8) micro g/L vs (43.3 +/- 26.8) micro g/L and sTfR (67.2 +/- 40.3) nmol/L vs (15.6 +/- 4.1) nmol/L (P 0.05) but SF (627.3 +/- 40.3) micro g/L level was increased in ACD1 group as compared with the control group (P < 0.01). Bone marrow iron stain showed no iron deficiency in 10 cases of ACD1. In ACD2 group, SF (320.5 +/- 156.0) micro g/L level was higher than that of the control group, but lower than that of the ACD1 group (P <or= 0.01); bone marrow iron stain showed iron depletion in 14 of the 16 patients. CONCLUSION: High sTfR level may reflect iron deficiency status of the body and is a more sensitive parameter to diagnose iron deficiency anemia. sTfR level is less influenced by chronic inflammation, and able to distinguish ACD from ACD-IDA.

Anemia↗
PubMed2004

Differential acetylcholine and choline concentrations in the cerebrospinal fluid of patients with Alzheimer's disease and vascular dementia.

BACKGROUND: An important aspect of Alzheimer's disease (AD) is loss or impairment of cholinergic neurons. It is controversial whether there is a similar cholinergic impairment and cerebral deficit of acetylcholine (ACh) in the case of vascular dementia (VD). The purpose of this study was to explore the levels of ACh and choline (Ch) in the cerebrospinal fluid (CSF) of patients with AD and VD, and their possible relationship with cognitive impairment. METHODS: Twenty-two AD patients, twenty-two VD patients, and twenty normal controls were recruited and scored with a Mini-Mental State Examination (MMSE). CSF concentrations of ACh and Ch were measured using high-performance liquid chromatography with an electrochemical detector (HPLC-ECD) and the results were then compared to cognitive status. RESULTS: ACh concentrations in CSF of AD patients [(10.7 +/- 5.1) nmol/L] and VD patients [(16.8 +/- 7.4) nmol/L] were both significantly lower than in controls [(34.5 +/- 9.0) nmol/L, t = 10.67, P < 0.001; t = 6.91, P < 0.001]. Both results correlated positively with MMSE scores (rs = 0.88 and rs = 0.85, respectively, P < 0.01). The CSF concentration of Ch was significantly higher in VD patients [(887.4 +/- 187.4) nmol/L] compared to AD patients [(627.6 +/- 145.1) nmol/L, t = 6.4, P < 0.001] and controls [(716.0 +/- 159.4) nmol/L, t = 4.2, P = 0.002]. CSF Ch concentration showed no difference between AD patients and normal controls, nor did it correlate with MMSE score in any of the three groups. CONCLUSIONS: The positive correlation between ACh deficit and cognitive impairment suggests that ACh is an important neurotransmitter for memory. The similar decrease in ACh concentration in AD and VD patients may imply a similar pathogenesis for the process of cognitive impairment involved in these two disorders. The elevated CSF levels of Ch in VD patients compared to AD patients may be useful diagnostically. Cholinesterase inhibitors may be helpful not only for AD patients, but also for VD patients.

Acetylcholine↗
PubMed2004

[Fe(II) enhanced sonochemical degradation of azo dye Acid Red B (ARB)].

Sonochemical degradation of azo dye Acid Red B (ARB) was studied in this paper. The effect of pH and ferrous ion concentrations on the process was investigated. The results show that decolorization of ARB proceeds faster in acidic medium. The production of H2O2 is proportional to sonication time. The presence of Fe(II), which could react with H2O2 to produce *OH, enhances the sonochemical decolorizatio and degradation of the dye. The decolorization rates of ARB are 2.17 and 2.75 times faster, respectively, when Fe(II) concentrations are 1.43 mg/L and 2.85 mg/L. The UV absorptions at 322 nm and 254 nm also reduce ARB dramatically.

Azo Compounds↗
PubMed2003

Light extinction and absorption by arbitrarily oriented finite circular cylinders by use of geometrical path statistics of rays.

From the geometrical path statistics of rays in an anomalous-diffraction theory (ADT) [Opt. Lett. 28, 179 (2003)] closed-form expressions for the geometrical path distribution of rays and analytical formulas for the optical efficiencies of finite circular cylinders oriented in an arbitrary direction with respect to the incident light are derived. The characteristics of the shapes of the cylinders produce unique features in the geometrical path distributions of the cylinders compared with spheroids. Gaussian ray approximations, which depend only on the mean and the mean-squared geometrical paths of rays, of the optical efficiencies of finite circular cylinders and spheroids are compared with the exact optical efficiencies in ADT. The influence of the difference in shape between cylinders and spheroids on the optical efficiencies in ADT is illustrated by their respective geometrical path distributions of rays.

Light↗