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Sample records for proximal mlh1 promoter

  1. Lynch syndrome associated with two MLH1 promoter variants and allelic imbalance of MLH1 expression.

    Science.gov (United States)

    Hesson, Luke B; Packham, Deborah; Kwok, Chau-To; Nunez, Andrea C; Ng, Benedict; Schmidt, Christa; Fields, Michael; Wong, Jason W H; Sloane, Mathew A; Ward, Robyn L

    2015-06-01

    Lynch syndrome is a hereditary cancer syndrome caused by a constitutional mutation in one of the mismatch repair genes. The implementation of predictive testing and targeted preventative surveillance is hindered by the frequent finding of sequence variants of uncertain significance in these genes. We aimed to determine the pathogenicity of previously reported variants (c.-28A>G and c.-7C>T) within the MLH1 5'untranslated region (UTR) in two individuals from unrelated suspected Lynch syndrome families. We investigated whether these variants were associated with other pathogenic alterations using targeted high-throughput sequencing of the MLH1 locus. We also determined their relationship to gene expression and epigenetic alterations at the promoter. Sequencing revealed that the c.-28A>G and c.-7C>T variants were the only potentially pathogenic alterations within the MLH1 gene. In both individuals, the levels of transcription from the variant allele were reduced to 50% compared with the wild-type allele. Partial loss of expression occurred in the absence of constitutional epigenetic alterations within the MLH1 promoter. We propose that these variants may be pathogenic due to constitutional partial loss of MLH1 expression, and that this may be associated with intermediate penetrance of a Lynch syndrome phenotype. Our findings provide further evidence of the potential importance of noncoding variants in the MLH1 5'UTR in the pathogenesis of Lynch syndrome. © 2015 The Authors. **Human Mutation published by Wiley Periodicals, Inc.

  2. Haplotype defined by the MLH1-93G/A polymorphism is associated with MLH1 promoter hypermethylation in sporadic colorectal cancers.

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    Miyakura, Yasuyuki; Tahara, Makiko; Lefor, Alan T; Yasuda, Yoshikazu; Sugano, Kokichi

    2014-11-24

    Methylation of the MLH1 promoter region has been suggested to be a major mechanism of gene inactivation in sporadic microsatellite instability-positive (MSI-H) colorectal cancers (CRCs). Recently, single-nucleotide polymorphism (SNP) in the MLH1 promoter region (MLH1-93G/A; rs1800734) has been proposed to be associated with MLH1 promoter methylation, loss of MLH1 protein expression and MSI-H tumors. We examined the association of MLH1-93G/A and six other SNPs surrounding MLH1-93G/A with the methylation status in 210 consecutive sporadic CRCs in Japanese patients. Methylation of the MLH1 promoter region was evaluated by Na-bisulfite polymerase chain reaction (PCR)/single-strand conformation polymorphism (SSCP) analysis. The genotype frequencies of SNPs located in the 54-kb region surrounding the MLH1-93G/A SNP were examined by SSCP analysis. Methylation of the MLH1 promoter region was observed in 28.6% (60/210) of sporadic CRCs. The proportions of MLH1-93G/A genotypes A/A, A/G and G/G were 26% (n=54), 51% (n=108) and 23% (n=48), respectively, and they were significantly associated with the methylation status (p=0.01). There were no significant associations between genotype frequency of the six other SNPs and methylation status. The A-allele of MLH1-93G/A was more common in cases with methylation than the G-allele (p=0.0094), especially in females (p=0.0067). In logistic regression, the A/A genotype of the MLH1-93G/A SNP was shown to be the most significant risk factor for methylation of the MLH1 promoter region (odds ratio 2.82, p=0.003). Furthermore, a haplotype of the A-allele of rs2276807 located -47 kb upstream from the MLH1-93G/A SNP and the A-allele of MLH1-93G/A SNP was significantly associated with MLH1 promoter methylation. These results indicate that individuals, and particularly females, carrying the A-allele at the MLH1-93G/A SNP, especially in association with the A-allele of rs2276807, may harbor an increased risk of methylation of the MLH1 promoter

  3. Prognostic value of MLH1 promoter methylation in male patients with esophageal squamous cell carcinoma.

    Science.gov (United States)

    Wu, Dongping; Chen, Xiaoying; Xu, Yan; Wang, Haiyong; Yu, Guangmao; Jiang, Luping; Hong, Qingxiao; Duan, Shiwei

    2017-04-01

    The DNA mismatch repair (MMR) gene MutL homolog 1 ( MLH1 ) is critical for the maintenance of genomic integrity. Methylation of the MLH1 gene promoter was identified as a prognostic marker for numerous types of cancer including glioblastoma, colorectal, ovarian and gastric cancer. The present study aimed to determine whether MLH1 promoter methylation was associated with survival in male patients with esophageal squamous cell carcinoma (ESCC). Formalin-fixed, paraffin-embedded ESCC tissues were collected from 87 male patients. MLH1 promoter methylation was assessed using the methylation-specific polymerase chain reaction approach. Kaplan-Meier survival curves and log-rank tests were used to evaluate the association between MLH1 promoter methylation and overall survival (OS) in patients with ESCC. Cox regression analysis was used to obtain crude and multivariate hazard ratios (HR), and 95% confidence intervals (CI). The present study revealed that MLH1 promoter methylation was observed in 53/87 (60.9%) of male patients with ESCC. Kaplan-Meier survival analysis demonstrated that MLH1 promoter hypermethylation was significantly associated with poorer prognosis in patients with ESCC (P=0.048). Multivariate survival analysis revealed that MLH1 promoter hypermethylation was an independent predictor of poor OS in male patients with ESCC (HR=1.716; 95% CI=1.008-2.921). Therefore, MLH1 promoter hypermethylation may be a predictor of prognosis in male patients with ESCC.

  4. MLH1-deficient Colorectal Carcinoma With Wild-type BRAF and MLH1 Promoter Hypermethylation Harbor KRAS Mutations and Arise From Conventional Adenomas.

    Science.gov (United States)

    Farchoukh, Lama; Kuan, Shih-Fan; Dudley, Beth; Brand, Randall; Nikiforova, Marina; Pai, Reetesh K

    2016-10-01

    Between 10% and 15% of colorectal carcinomas demonstrate sporadic DNA mismatch-repair protein deficiency as a result of MLH1 promoter methylation and are thought to arise from sessile serrated adenomas, termed the serrated neoplasia pathway. Although the presence of the BRAF V600E mutation is indicative of a sporadic cancer, up to 30% to 50% of colorectal carcinomas with MLH1 promoter hypermethylation will lack a BRAF mutation. We report the clinicopathologic and molecular features of MLH1-deficient colorectal carcinoma with wild-type BRAF and MLH1 promoter hypermethylation (referred to as MLH1-hypermethylated BRAF wild-type colorectal carcinoma, n=36) in comparison with MLH1-deficient BRAF-mutated colorectal carcinoma (n=113) and Lynch syndrome-associated colorectal carcinoma (n=36). KRAS mutations were identified in 31% of MLH1-hypermethylated BRAF wild-type colorectal carcinomas compared with 0% of MLH1-deficient BRAF-mutated colorectal carcinomas and 37% of Lynch syndrome-associated colorectal carcinomas. When a precursor polyp was identified, MLH1-hypermethylated BRAF wild-type colorectal carcinomas arose from precursor polyps resembling conventional tubular/tubulovillous adenomas in contrast to MLH1-deficient BRAF-mutated colorectal carcinomas, which arose from precursor sessile serrated adenomas (PMLH1-hypermethylated BRAF wild-type colorectal carcinoma and MLH1-deficient BRAF-mutated colorectal carcinoma had a predilection for the right colon compared with Lynch syndrome-associated colorectal carcinoma (86% vs. 92% vs. 49%, P0.05). In conclusion, our results indicate that MLH1-hypermethylated BRAF wild-type colorectal carcinomas can harbor KRAS mutations and arise from precursor polyps resembling conventional tubular/tubulovillous adenomas.

  5. Lynch syndrome-associated endometrial carcinoma with MLH1 germline mutation and MLH1 promoter hypermethylation: a case report and literature review.

    Science.gov (United States)

    Yokoyama, Takanori; Takehara, Kazuhiro; Sugimoto, Nao; Kaneko, Keika; Fujimoto, Etsuko; Okazawa-Sakai, Mika; Okame, Shinichi; Shiroyama, Yuko; Yokoyama, Takashi; Teramoto, Norihiro; Ohsumi, Shozo; Saito, Shinya; Imai, Kazuho; Sugano, Kokichi

    2018-05-21

    Lynch syndrome is an autosomal dominant inherited disease caused by germline mutations in mismatch repair genes. Analysis for microsatellite instability (MSI) and immunohistochemistry (IHC) of protein expressions of disease-associated genes is used to screen for Lynch syndrome in endometrial cancer patients. When losses of both MLH1 and PMS2 proteins are observed by IHC, MLH1 promoter methylation analysis is conducted to distinguish Lynch syndrome-associated endometrial cancer from sporadic cancer. Here we report a woman who developed endometrial cancer at the age of 49 years. She had a family history of colorectal cancer (first-degree relative aged 52 years) and stomach cancer (second-degree relative with the age of onset unknown). No other family history was present, and she failed to meet the Amsterdam II criteria for the diagnosis of Lynch syndrome. Losses of MLH1 and PMS2, but not MSH2 and MSH6, proteins were observed by IHC in endometrial cancer tissues. Because MLH1 promoter hypermethylation was detected in endometrial cancer tissue samples, the epigenetic silencing of MLH1 was suspected as the cause of the protein loss. However, because of the early onset of endometrial cancer and the positive family history, a diagnosis of Lynch syndrome was also suspected. Therefore, we provided her with genetic counseling. After obtaining her consent, MLH1 promoter methylation testing and genetic testing of peripheral blood were performed. MLH1 promoter methylation was not observed in peripheral blood. However, genetic testing revealed a large deletion of exon 5 in MLH1; thus, we diagnosed the presence of Lynch syndrome. Both MLH1 germline mutation and MLH1 promoter hypermethylation may be observed in endometrial cancer. Therefore, even if MLH1 promoter hypermethylation is detected, a diagnosis of Lynch syndrome cannot be excluded.

  6. Expression and promoter DNA methylation of MLH1 in colorectal cancer and lung cancer.

    Science.gov (United States)

    Ma, Yunxia; Chen, Yuan; Petersen, Iver

    2017-04-01

    Aberrant DNA methylation is a common molecular feature in human cancer. The aims of this study were to analyze the methylation status of MLH1, one of the DNA mismatch repair (MMR) genes, in human colorectal and lung cancer and to evaluate its clinical relevance. The expression of MLH1 was analyzed in 8 colorectal cancer (CRC) and 8 lung cancer cell lines by real-time RT-PCR and western blotting. The MLH1 protein expression was evaluated by immunohistochemistry on tissue microarrays including 121 primary CRC and 90 lung cancer patient samples. In cancer cell lines, the methylation status of MLH1 promoter and exon 2 was investigated by bisulfite sequencing (BS). Methylation-specific-PCR (MSP) was used to evaluate methylation status of MLH1. The expression of MLH1 mRNA was detected in 8 CRC cell lines as well as normal colonic fibroblast cells CCD-33Co. At protein levels, MLH1 was lost in one CRC cell line HCT-116 and normal cells CCD-33Co. No methylation was found in the promoter and exon 2 of MLH1 in CRC cell lines. MLH1 was expressed in 8 lung cancer cell lines at both mRNA and protein levels. Compared to cancer cells, normal bronchial epithelial cells (HBEC) had lower expression of MLH1 protein. In primary CRC, 54.5% of cases exhibited positive staining, while 47.8% of lung tumors were positive for MLH1 protein. MSP analysis showed that 58 out of 92 (63.0%) CRC and 41 out of 73 (56.2%) lung cancer exhibited MLH1 methylation. In CRC, the MLH1 methylation was significantly associated with tumor invasion in veins (P=0.012). However, no significant links were found between MLH1 expression and promoter methylation in both tumor entities. MLH1 methylation is a frequent molecular event in CRC and lung cancer patients. In CRC, methylation of MLH1 could be linked to vascular invasiveness. Copyright © 2017 Elsevier GmbH. All rights reserved.

  7. Clinicopathologic Risk Factor Distributions for MLH1 Promoter Region Methylation in CIMP-Positive Tumors.

    Science.gov (United States)

    Levine, A Joan; Phipps, Amanda I; Baron, John A; Buchanan, Daniel D; Ahnen, Dennis J; Cohen, Stacey A; Lindor, Noralane M; Newcomb, Polly A; Rosty, Christophe; Haile, Robert W; Laird, Peter W; Weisenberger, Daniel J

    2016-01-01

    The CpG island methylator phenotype (CIMP) is a major molecular pathway in colorectal cancer. Approximately 25% to 60% of CIMP tumors are microsatellite unstable (MSI-H) due to DNA hypermethylation of the MLH1 gene promoter. Our aim was to determine if the distributions of clinicopathologic factors in CIMP-positive tumors with MLH1 DNA methylation differed from those in CIMP-positive tumors without DNA methylation of MLH1. We assessed the associations between age, sex, tumor-site, MSI status BRAF and KRAS mutations, and family colorectal cancer history with MLH1 methylation status in a large population-based sample of CIMP-positive colorectal cancers defined by a 5-marker panel using unconditional logistic regression to assess the odds of MLH1 methylation by study variables. Subjects with CIMP-positive tumors without MLH1 methylation were significantly younger, more likely to be male, and more likely to have distal colon or rectal primaries and the MSI-L phenotype. CIMP-positive MLH1-unmethylated tumors were significantly less likely than CIMP-positive MLH1-methylated tumors to harbor a BRAF V600E mutation and significantly more likely to harbor a KRAS mutation. MLH1 methylation was associated with significantly better overall survival (HR, 0.50; 95% confidence interval, 0.31-0.82). These data suggest that MLH1 methylation in CIMP-positive tumors is not a completely random event and implies that there are environmental or genetic determinants that modify the probability that MLH1 will become methylated during CIMP pathogenesis. MLH1 DNA methylation status should be taken into account in etiologic studies. ©2015 American Association for Cancer Research.

  8. Clinicopathological risk factor distributions for MLH1 promoter region methylation in CIMP positive tumors

    Science.gov (United States)

    Levine, A. Joan; Phipps, Amanda I.; Baron, John A.; Buchanan, Daniel D.; Ahnen, Dennis J.; Cohen, Stacey A.; Lindor, Noralane M.; Newcomb, Polly A.; Rosty, Christophe; Haile, Robert W.; Laird, Peter W.; Weisenberger, Daniel J.

    2015-01-01

    Background The CpG Island Methylator Phenotype (CIMP) is a major molecular pathway in colorectal cancer (CRC). Approximately 25% to 60% of CIMP tumors are microsatellite unstable (MSI-H) due to DNA hypermethylation of the MLH1 gene promoter. Our aim was to determine if the distributions of clinicopathologic factors in CIMP-positive tumors with MLH1 DNA methylation differed from those in CIMP-positive tumors without DNA methylation of MLH1. Methods We assessed the associations between age, sex, tumor-site, MSI status BRAF and KRAS mutations and family CRC history with MLH1 methylation status in a large population-based sample of CIMP-positive CRCs defined by a 5-marker panel using unconditional logistic regression to assess the odds of MLH1 methylation by study variables. Results Subjects with CIMP-positive tumors without MLH1 methylation were significantly younger, more likely to be male, more likely to have distal colon or rectal primaries and the MSI-L phenotype. CIMP-positive MLH1-unmethylated tumors were significantly less likely than CIMP-positive MLH1-methylated tumors to harbor a BRAF V600E mutation and significantly more likely to harbor a KRAS mutation. MLH1 methylation was associated with significantly better overall survival (HR=0.50; 95% Confidence Interval (0.31, 0.82)). Conclusions These data suggest that MLH1 methylation in CIMP-positive tumors is not a completely random event and implies that there are environmental or genetic determinants that modify the probability that MLH1 will become methylated during CIMP pathogenesis. Impact MLH1 DNA methylation status should be taken into account in etiologic studies. PMID:26512054

  9. MLH1 promoter methylation frequency in colorectal cancer patients and related clinicopathological and molecular features.

    Directory of Open Access Journals (Sweden)

    Xia Li

    Full Text Available To describe the frequency of MLH1 promoter methylation in colorectal cancer (CRC; to explore the associations between MLH1 promoter methylation and clinicopathological and molecular factors using a systematic review and meta-analysis.A literature search of the PubMed and Embase databases was conducted to identify relevant articles published up to September 7, 2012 that described the frequency of MLH1 promoter methylation or its associations with clinicopathological and molecular factors in CRC. The pooled frequency, odds ratio (OR and 95% confidence intervals (95% CI were calculated.The pooled frequency of MLH1 promoter methylation in unselected CRC was 20.3% (95% CI: 16.8-24.1%. They were 18.7% (95% CI: 14.7-23.6% and 16.4% (95% CI: 11.9-22.0% in sporadic and Lynch syndrome (LS CRC, respectively. Significant associations were observed between MLH1 promoter methylation and gender (pooled OR = 1.641, 95% CI: 1.215-2.215; P = 0.001, tumor location (pooled OR = 3.804, 95% CI: 2.715-5.329; P<0.001, tumor differentiation (pooled OR = 2.131, 95% CI: 1.464-3.102; P<0.001, MSI (OR: 27.096, 95% CI: 13.717-53.526; P<0.001. Significant associations were also observed between MLH1 promoter methylation and MLH1 protein expression, BRAF mutation (OR = 14.919 (95% CI: 6.427-34.631; P<0.001 and 9.419 (95% CI: 2.613-33.953; P = 0.001, respectively.The frequency of MLH1 promoter methylation in unselected CRC was 20.3%. They were 18.7% in sporadic CRC and 16.4% in LS CRC, respectively. MLH1 promoter methylation may be significantly associated with gender, tumor location, tumor differentiation, MSI, MLH1 protein expression, and BRAF mutation.

  10. MLH1 Promoter Methylation Frequency in Colorectal Cancer Patients and Related Clinicopathological and Molecular Features

    Science.gov (United States)

    Li, Xia; Yao, Xiaoping; Wang, Yibaina; Hu, Fulan; Wang, Fan; Jiang, Liying; Liu, Yupeng; Wang, Da; Sun, Guizhi; Zhao, Yashuang

    2013-01-01

    Purpose To describe the frequency of MLH1 promoter methylation in colorectal cancer (CRC); to explore the associations between MLH1 promoter methylation and clinicopathological and molecular factors using a systematic review and meta-analysis. Methods A literature search of the PubMed and Embase databases was conducted to identify relevant articles published up to September 7, 2012 that described the frequency of MLH1 promoter methylation or its associations with clinicopathological and molecular factors in CRC. The pooled frequency, odds ratio (OR) and 95% confidence intervals (95% CI) were calculated. Results The pooled frequency of MLH1 promoter methylation in unselected CRC was 20.3% (95% CI: 16.8–24.1%). They were 18.7% (95% CI: 14.7–23.6%) and 16.4% (95% CI: 11.9–22.0%) in sporadic and Lynch syndrome (LS) CRC, respectively. Significant associations were observed between MLH1 promoter methylation and gender (pooled OR = 1.641, 95% CI: 1.215–2.215; P = 0.001), tumor location (pooled OR = 3.804, 95% CI: 2.715–5.329; PMLH1 promoter methylation and MLH1 protein expression, BRAF mutation (OR = 14.919 (95% CI: 6.427–34.631; PMLH1 promoter methylation in unselected CRC was 20.3%. They were 18.7% in sporadic CRC and 16.4% in LS CRC, respectively. MLH1 promoter methylation may be significantly associated with gender, tumor location, tumor differentiation, MSI, MLH1 protein expression, and BRAF mutation. PMID:23555617

  11. Tumour MLH1 promoter region methylation testing is an effective prescreen for Lynch Syndrome (HNPCC).

    Science.gov (United States)

    Newton, K; Jorgensen, N M; Wallace, A J; Buchanan, D D; Lalloo, F; McMahon, R F T; Hill, J; Evans, D G

    2014-12-01

    Lynch syndrome (LS) patients have DNA mismatch repair deficiency and up to 80% lifetime risk of colorectal cancer (CRC). Screening of mutation carriers reduces CRC incidence and mortality. Selection for constitutional mutation testing relies on family history (Amsterdam and Bethesda Guidelines) and tumour-derived biomarkers. Initial biomarker analysis uses mismatch repair protein immunohistochemistry and microsatellite instability. Abnormalities in either identify mismatch repair deficiency but do not differentiate sporadic epigenetic defects, due to MLH1 promoter region methylation (13% of CRCs) from LS (4% of CRCs). A diagnostic biomarker capable of making this distinction would be valuable. This study compared two biomarkers in tumours with mismatch repair deficiency; quantification of methylation of the MLH1 promoter region using a novel assay and BRAF c.1799T>A, p.(Val600Glu) mutation status in the identification of constitutional mutations. Tumour DNA was extracted (formalin fixed, paraffin embedded, FFPE tissue) and pyrosequencing used to test for MLH1 promoter methylation and presence of the BRAF c.1799T>A, p.(Val600Glu) mutation 71 CRCs from individuals with pathogenic MLH1 mutations and 73 CRCs with sporadic MLH1 loss. Specificity and sensitivity was compared. Unmethylated MLH1 promoter: sensitivity 94.4% (95% CI 86.2% to 98.4%), specificity 87.7% (95% CI 77.9% to 94.2%), Wild-type BRAF (codon 600): sensitivity 65.8% (95% CI 53.7% to 76.5%), specificity 98.6% (95% CI 92.4% to 100.0%) for the identification of those with pathogenic MLH1 mutations. Quantitative MLH1 promoter region methylation using pyrosequencing is superior to BRAF codon 600 mutation status in identifying constitutional mutations in mismatch repair deficient tumours. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  12. Regulation of MLH1 mRNA and protein expression by promoter methylation in primary colorectal cancer

    DEFF Research Database (Denmark)

    Jensen, Lars Henrik; Rasmussen, Anders Aamann; Byriel, Lene

    2013-01-01

    In colorectal cancer MLH1 deficiency causes microsatellite instability, which is relevant for the patient's prognosis and treatment, and its putative heredity. Dysfunction of MLH1 is caused by sporadic gene promoter hypermethylation or by hereditary mutations as seen in Lynch Syndrome. The aim...... of this study was to determine in detail how DNA methylation regulates MLH1 expression and impacts clinical management....

  13. Identification of constitutional MLH1 epimutations and promoter variants in colorectal cancer patients from the Colon Cancer Family Registry

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    Ward, Robyn L.; Dobbins, Timothy; Lindor, Noralane M.; Rapkins, Robert W.; Hitchins, Megan P.

    2013-01-01

    Purpose: Constitutional MLH1 epimutations manifest as promoter methylation and silencing of the affected allele in normal tissues, predisposing to Lynch syndrome–associated cancers. This study investigated their frequency and inheritance. Methods: A total of 416 individuals with a colorectal cancer showing loss of MLH1 expression and without deleterious germline mutations in MLH1 were ascertained from the Colon Cancer Family Registry (C-CFR). Constitutive DNA samples were screened for MLH1 methylation in all 416 subjects and for promoter sequence changes in 357 individuals. Results: Constitutional MLH1 epimutations were identified in 16 subjects. Of these, seven (1.7%) had mono- or hemi-allelic methylation and eight had low-level methylation (2%). In one subject the epimutation was linked to the c.-27C>A promoter variant. Testing of 37 relatives from nine probands revealed paternal transmission of low-level methylation segregating with a c.+27G>A variant in one case. Five additional probands had a promoter variant without an MLH1 epimutation, with three showing diminished promoter activity in functional assays. Conclusion: Although rare, sequence changes in the regulatory region of MLH1 and aberrant methylation may alone or together predispose to the development of cancer. Screening for these changes is warranted in individuals who have a negative germline sequence screen of MLH1 and loss of MLH1 expression in their tumor. PMID:22878509

  14. Evaluation of promoter methylation status of MLH1 gene in Iranian patients with colorectal tumors and adenoma polyps.

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    Zarandi, Ashkan; Irani, Shiva; Savabkar, Sanaz; Chaleshi, Vahid; Ghavideldarestani, Maryam; Mirfakhraie, Reza; Khodadoostan, Mahsa; Nazemalhosseini-Mojarad, Ehsan; Asadzadeh Aghdaei, Hamid

    2017-01-01

    The aim of this study was to evaluate the methylation status of the promoter region of MLH1 gene in colorectal cancer (CRC) and its precursor lesions as well as elucidate its association with various clinicopathological characteristics among Iranian population. Epigenetic silencing of mismatch repair genes, such as MLH1 , by methylation of CpG islands of their promoter region has been proved to be an important mechanism in colorectal carcinogenesis. Fifty colorectal cancer and polyp tissue samples including 13 Primary colorectal tumor and 37 Adenoma polyp samples were enrolled in this study. Methylation-specific polymerase chain reaction (MSP) was performed to find the frequency of MLH1 Promoter Methylation. Promoter methylation of MLH1 gene was detected in 5 out of 13 tumor tissues and 4 out of 37 adenoma polyp. The frequency of MLH1 methylation in tumor samples was significantly higher compared to that in polyp tissues (P= 0.026). No significant association was observed between MLH1 promoter methylation and clinicopathological characteristics of the patients. The frequency of  MLH1  promoter methylation in CRC and colon polyp was 18%. Our findings indicated that methylation of MLH1 promoter region alone cannot be considered as a biomarker for early detection of CRC.

  15. Epigenetic Loss of MLH1 Expression in Normal Human Hematopoietic Stem Cell Clones is Defined by the Promoter CpG Methylation Pattern Observed by High-Throughput Methylation Specific Sequencing.

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    Kenyon, Jonathan; Nickel-Meester, Gabrielle; Qing, Yulan; Santos-Guasch, Gabriela; Drake, Ellen; PingfuFu; Sun, Shuying; Bai, Xiaodong; Wald, David; Arts, Eric; Gerson, Stanton L

    Normal human hematopoietic stem and progenitor cells (HPC) lose expression of MLH1 , an important mismatch repair (MMR) pathway gene, with age. Loss of MMR leads to replication dependent mutational events and microsatellite instability observed in secondary acute myelogenous leukemia and other hematologic malignancies. Epigenetic CpG methylation upstream of the MLH1 promoter is a contributing factor to acquired loss of MLH1 expression in tumors of the epithelia and proximal mucosa. Using single molecule high-throughput bisulfite sequencing we have characterized the CpG methylation landscape from -938 to -337 bp upstream of the MLH1 transcriptional start site (position +0), from 30 hematopoietic colony forming cell clones (CFC) either expressing or not expressing MLH1 . We identify a correlation between MLH1 promoter methylation and loss of MLH1 expression. Additionally, using the CpG site methylation frequencies obtained in this study we were able to generate a classification algorithm capable of sorting the expressing and non-expressing CFC. Thus, as has been previously described for many tumor cell types, we report for the first time a correlation between the loss of MLH1 expression and increased MLH1 promoter methylation in CFC derived from CD34 + selected hematopoietic stem and progenitor cells.

  16. Promoter hypermethylation of mismatch repair gene hMLH1 predicts the clinical response of malignant astrocytomas to nitrosourea.

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    Fukushima, Takao; Katayama, Yoichi; Watanabe, Takao; Yoshino, Atsuo; Ogino, Akiyoshi; Ohta, Takashi; Komine, Chiaki

    2005-02-15

    In certain types of human cancers, transcriptional inactivation of hMLH1 by promoter hypermethylation plays a causal role in the loss of mismatch repair functions that modulate cytotoxic pathways in response to DNA-damaging agents. The aim of the present study was to investigate the role of promoter methylation of the hMLH1 gene in malignant astrocytomas. We examined the hMLH1 promoter methylation in a homogeneous cohort of patients with 41 malignant astrocytomas treated by 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-2(2-chloroethyl)-3-nitrosourea chemotherapy in combination with radiation and interferon therapy, and assessed the correlation of such methylation with clinical outcome. hMLH1 promoter methylation was found in 6 (15%) of the 41 newly diagnosed malignant astrocytomas. Hypermethylation of the hMLH1 promoter corresponded closely with a loss of immunohistochemical staining for hMLH1 protein (P = 0.0013). Patients with hMLH1-methylated tumors displayed a greater chance of responding to adjuvant therapy as compared with those with hMLH1-unmethylated tumors (P = 0.0150). The presence of hMLH1 hypermethylation was significantly associated with a longer progression-free survival on both univariate analysis (P = 0.0340) and multivariate analysis (P = 0.0161). The present study identified hMLH1 methylation status as a predictor of the clinical response of malignant astrocytomas to chloroethylnitrosourea-based adjuvant therapy. The findings obtained suggest that determination of the methylation status of hMLH1 could provide a potential basis for designing rational chemotherapeutic strategies, as well as for predicting prognosis.

  17. Biallelic MLH1 SNP cDNA expression or constitutional promoter methylation can hide genomic rearrangements causing Lynch syndrome.

    Science.gov (United States)

    Morak, Monika; Koehler, Udo; Schackert, Hans Konrad; Steinke, Verena; Royer-Pokora, Brigitte; Schulmann, Karsten; Kloor, Matthias; Höchter, Wilhelm; Weingart, Josef; Keiling, Cortina; Massdorf, Trisari; Holinski-Feder, Elke

    2011-08-01

    A positive family history, germline mutations in DNA mismatch repair genes, tumours with high microsatellite instability, and loss of mismatch repair protein expression are the hallmarks of hereditary non-polyposis colorectal cancer (Lynch syndrome). However, in ~10-15% of cases of suspected Lynch syndrome, no disease-causing mechanism can be detected. Oligo array analysis was performed to search for genomic imbalances in patients with suspected mutation-negative Lynch syndrome with MLH1 deficiency in their colorectal tumours. A deletion in the LRRFIP2 (leucine-rich repeat flightless-interacting protein 2) gene flanking the MLH1 gene was detected, which turned out to be a paracentric inversion on chromosome 3p22.2 creating two new stable fusion transcripts between MLH1 and LRRFIP2. A single-nucleotide polymorphism in MLH1 exon 8 was expressed from both alleles, initially pointing to appropriate MLH1 function at least in peripheral cells. In a second case, an inherited duplication of the MLH1 gene region resulted in constitutional MLH1 promoter methylation. Constitutional MLH1 promoter methylation may therefore in rare cases be a heritable disease mechanism and should not be overlooked in seemingly sporadic patients.

  18. Comprehensive analysis of the MLH1 promoter region in 480 patients with colorectal cancer and 1150 controls reveals new variants including one with a heritable constitutional MLH1 epimutation.

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    Morak, Monika; Ibisler, Ayseguel; Keller, Gisela; Jessen, Ellen; Laner, Andreas; Gonzales-Fassrainer, Daniela; Locher, Melanie; Massdorf, Trisari; Nissen, Anke M; Benet-Pagès, Anna; Holinski-Feder, Elke

    2018-04-01

    Germline defects in MLH1 , MSH2 , MSH6 and PMS2 predisposing for Lynch syndrome (LS) are mainly based on sequence changes, whereas a constitutional epimutation of MLH1 (CEM) is exceptionally rare. This abnormal MLH1 promoter methylation is not hereditary when arising de novo, whereas a stably heritable and variant-induced CEM was described for one single allele. We searched for MLH1 promoter variants causing a germline or somatic methylation induction or transcriptional repression. We analysed the MLH1 promoter sequence in five different patient groups with colorectal cancer (CRC) (n=480) composed of patients with i) CEM (n=16), ii) unsolved loss of MLH1 expression in CRC (n=37), iii) CpG-island methylator-phenotype CRC (n=102), iv) patients with LS (n=83) and v) MLH1-proficient CRC (n=242) as controls. 1150 patients with non-LS tumours also served as controls to correctly judge the results. We detected 10 rare MLH1 promoter variants. One novel, complex MLH1 variant c.-63_-58delins18 is present in a patient with CRC with CEM and his sister, both showing a complete allele-specific promoter methylation and transcriptional silencing. The other nine promoter variants detected in 17 individuals were not associated with methylation. For four of these, a normal, biallelic MLH1 expression was found in the patients' cDNA. We report the second promoter variant stably inducing a hereditary CEM. Concerning the classification of promoter variants, we discuss contradictory results from the literature for two variants, describe classification discrepancies between existing rules for five variants, suggest the (re-)classification of five promoter variants to (likely) benign and regard four variants as functionally unclear. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  19. MLH1-93 G/a polymorphism is associated with MLH1 promoter methylation and protein loss in dysplastic sessile serrated adenomas with BRAFV600E mutation.

    Science.gov (United States)

    Fennell, Lochlan J; Jamieson, Saara; McKeone, Diane; Corish, Tracie; Rohdmann, Megan; Furner, Tori; Bettington, Mark; Liu, Cheng; Kawamata, Futoshi; Bond, Catherine; Van De Pols, Jolieke; Leggett, Barbara; Whitehall, Vicki

    2018-01-05

    Sessile serrated adenomas with BRAF mutation progress rapidly to cancer following the development of dysplasia (SSAD). Approximately 75% of SSADs methylate the mismatch repair gene MLH1, develop mismatch repair deficiency and the resultant cancers have a good prognosis. The remaining SSADs and BRAF mutant traditional serrated adenomas (TSA) develop into microsatellite stable cancers with a poor prognosis. The reason for this dichotomy is unknown. In this study, we assessed the genotypic frequency of the MLH1-93 polymorphism rs1800734 in SSADs and TSAs to determine if the uncommon variant A allele predisposes to MLH1 promoter hypermethylation. We performed genotyping for the MLH1-93 polymorphism, quantitative methylation specific PCR, and MLH1 immunohistochemistry on 124 SSAD, 128 TSA, 203 BRAF mutant CRCs and 147 control subjects with normal colonoscopy. The minor A allele was significantly associated with a dose dependent increase in methylation at the MLH1 promoter in SSADs (p = 0.022). The AA genotype was only observed in SSADs with MLH1 loss. The A allele was also overrepresented in BRAF mutant cancers with MLH1 loss. Only one of the TSAs showed loss of MLH1 and the overall genotype distribution in TSAs did not differ from controls. The MLH1-93 AA genotype is significantly associated with promoter hypermethylation and MLH1 loss in the context of SSADs. BRAF mutant microsatellite stable colorectal cancers with the AA genotype most likely arise in TSAs since the A allele does not predispose to methylation in this context.

  20. MLH1 Promoter Methylation and Prediction/Prognosis of Gastric Cancer: A Systematic Review and Meta and Bioinformatic Analysis.

    Science.gov (United States)

    Shen, Shixuan; Chen, Xiaohui; Li, Hao; Sun, Liping; Yuan, Yuan

    2018-01-01

    Background: The promoter methylation of MLH1 gene and gastric cancer (GC)has been investigated previously. To get a more credible conclusion, we performed a systematic review and meta and bioinformatic analysis to clarify the role of MLH1 methylation in the prediction and prognosis of GC. Methods: Eligible studies were targeted after searching the PubMed, Web of Science, Embase, BIOSIS, CNKI and Wanfang Data to collect the information of MLH1 methylation and GC. The link strength between the two was estimated by odds ratio with its 95% confidence interval. The Newcastle-Ottawa scale was used for quantity assessment . Subgroup and sensitivity analysis were conducted to explore sources of heterogeneity. The Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) were employed for bioinformatics analysis on the correlation between MLH1 methylation and GC risk, clinicopathological behavior as well as prognosis. Results: 2365 GC and 1563 controls were included in the meta-analysis. The pooled OR of MLH1 methylation in GC was 4.895 (95% CI: 3.149-7.611, PMLH1 methylation enhanced GC risk but might not related with GC clinicopathological features and prognosis. Conclusion: MLH1 methylation is an alive biomarker for the prediction of GC and it might not affect GC behavior. Further study could be conducted to verify the impact of MLH1 methylation on GC prognosis.

  1. Tumour MLH1 promoter region methylation testing is an effective pre-screen for Lynch Syndrome (HNPCC)

    Science.gov (United States)

    Newton, K; Jorgensen, NM; Wallace, AJ; Buchanan, DD; Lalloo, F; McMahon, RFT; Hill, J; Evans, DG

    2016-01-01

    Background & Aims Lynch syndrome patients have DNA mismatch repair deficiency and up to 80% life-time risk of colorectal cancer. Screening of mutation carriers reduces colorectal cancer incidence and mortality. Selection for constitutional mutation testing relies on family history (Amsterdam and Bethesda Guidelines) and tumour derived biomarkers. Initial biomarker analysis uses mismatch repair protein immunohistochemistry and microsatellite instability. Abnormalities in either identify mismatch repair deficiency but do not differentiate sporadic epigenetic defects, due to MLH1 promoter region methylation (13% of CRCs) from Lynch Syndrome (4% of CRCs). A diagnostic biomarker capable of making this distinction would be valuable. This study compared two biomarkers in tumours with mismatch repair deficiency; quantification of methylation of the MLH1 promoter region using a novel assay and BRAF c.1799T>A, p.(Val600Glu) mutation status in the identification of constitutional mutations. Methods Tumour DNA was extracted (FFPE tissue) and pyrosequencing used to test for MLH1 promoter methylation and presence of the BRAF c.1799T>A, p.(Val600Glu) mutation 71 CRCs from individuals with pathogenic MLH1 mutations and 73 CRCs with sporadic MLH1 loss. Specificity and sensitivity was compared. Findings Unmethylated MLH1 promoter: sensitivity 94.4% (95% CI 86.2–98.4%), specificity 87.7% (95% CI 77.9–94.2%), Wild-type BRAF (codon 600): sensitivity 65.8% (95% CI 53.7–76.5%), specificity 98.6% (95% CI 92.4–100.0%) for the identification of those with pathogenic MLH1 mutations. Conclusions Quantitative MLH1 promoter region methylation using pyrosequencing is superior to BRAF codon 600 mutation status in identifying constitutional mutations in mismatch repair deficient tumours. PMID:25280751

  2. Patients with colorectal cancer associated with Lynch syndrome and MLH1 promoter hypermethylation have similar prognoses.

    Science.gov (United States)

    Haraldsdottir, Sigurdis; Hampel, Heather; Wu, Christina; Weng, Daniel Y; Shields, Peter G; Frankel, Wendy L; Pan, Xueliang; de la Chapelle, Albert; Goldberg, Richard M; Bekaii-Saab, Tanios

    2016-09-01

    Mismatch repair-deficient (dMMR) colorectal cancer (CRC) is caused by Lynch syndrome (LS) in 3% and sporadic inactivation of MLH1 by hypermethylation (MLH1-hm) in 12% of cases. It is not clear whether outcomes between LS-associated and MLH1-hm CRC differ. The objective of this study was to explore differences in clinical factors and outcomes in these two groups. Patients with dMMR CRC identified by immunohistochemistry staining and treated at a single institution from 1998 to 2012 were included. MLH1-hm was established with BRAF mutational analysis or hypermethylation testing. Patients' charts were accessed for information on pathology, germ-line MMR mutation testing, and clinical course. A total of 143 patients had CRC associated with LS (37 patients, 26%) or MLH1-hm (106 patients, 74%). Patients with LS were younger, more often male, presented more often with stage III disease, and had more metachronous disease than patients with MLH1-hm tumors. There was no difference in cancer-specific survival (CSS) between the groups; overall survival was longer in patients with LS, but this difference was minimal after adjusting for age and stage at diagnosis. CSS did not differ in LS-associated CRC compared with MLH1-hm CRC, suggesting that they carry a similar prognosis.Genet Med 18 9, 863-868.

  3. Associations of dietary methyl donor intake with MLH1 promoter hypermethylation and related molecular phenotypes in sporadic colorectal cancer

    NARCIS (Netherlands)

    Vogel, S. de; Bongaerts, B.W.C.; Wouters, K.A.D.; Kester, A.D.M.; Schouten, L.J.; Goeij, A.F.P.M. de; Bruïne, A.P. de; Goldbohm, R.A.; Brandt, P.A. van den; Engeland, M. van; Weijenberg, M.P.

    2008-01-01

    Intake of dietary factors that serve as methyl group donors may influence promoter hypermethylation in colorectal carcinogenesis. We investigated whether dietary folate, vitamin B2 and vitamin B6, methionine and alcohol were associated with mutL homologue 1 (MLH1) hypermethylation and the related

  4. Early onset MSI-H colon cancer with MLH1 promoter methylation, is there a genetic predisposition?

    International Nuclear Information System (INIS)

    Roon, Eddy HJ van; Hes, Frederik J; Tops, Carli MJ; Wezel, Tom van; Boer, Judith M; Morreau, Hans; Puijenbroek, Marjo van; Middeldorp, Anneke; Eijk, Ronald van; Meijer, Emile J de; Erasmus, Dianhdra; Wouters, Kim AD; Engeland, Manon van; Oosting, Jan

    2010-01-01

    To investigate the etiology of MLH1 promoter methylation in mismatch repair (MMR) mutation-negative early onset MSI-H colon cancer. As this type of colon cancer is associated with high ages, young patients bearing this type of malignancy are rare and could provide additional insight into the etiology of sporadic MSI-H colon cancer. We studied a set of 46 MSI-H colon tumors cases with MLH1 promoter methylation which was enriched for patients with an age of onset below 50 years (n = 13). Tumors were tested for CIMP marker methylation and mutations linked to methylation: BRAF, KRAS, GADD45A and the MLH1 -93G>A polymorphism. When available, normal colon and leukocyte DNA was tested for GADD45A mutations and germline MLH1 methylation. SNP array analysis was performed on a subset of tumors. We identified two cases (33 and 60 years) with MLH1 germline promoter methylation. BRAF mutations were less frequent in colon cancer patients below 50 years relative to patients above 50 years (p-value: 0.044). CIMP-high was infrequent and related to BRAF mutations in patients below 50 years. In comparison with published controls the G>A polymorphism was associated with our cohort. Although similar distribution of the pathogenic A allele was observed in the patients with an age of onset above and below 50 years, the significance for the association was lost for the group under 50 years. GADD45A sequencing yielded an unclassified variant. Tumors from both age groups showed infrequent copy number changes and loss-of-heterozygosity. Somatic or germline GADD45A mutations did not explain sporadic MSI-H colon cancer. Although germline MLH1 methylation was found in two individuals, locus-specific somatic MLH1 hypermethylation explained the majority of sporadic early onset MSI-H colon cancer cases. Our data do not suggest an intrinsic tendency for CpG island hypermethylation in these early onset MSI-H tumors other than through somatic mutation of BRAF

  5. Early onset MSI-H colon cancer with MLH1 promoter methylation, is there a genetic predisposition?

    Directory of Open Access Journals (Sweden)

    Hes Frederik J

    2010-05-01

    Full Text Available Abstract Background To investigate the etiology of MLH1 promoter methylation in mismatch repair (MMR mutation-negative early onset MSI-H colon cancer. As this type of colon cancer is associated with high ages, young patients bearing this type of malignancy are rare and could provide additional insight into the etiology of sporadic MSI-H colon cancer. Methods We studied a set of 46 MSI-H colon tumors cases with MLH1 promoter methylation which was enriched for patients with an age of onset below 50 years (n = 13. Tumors were tested for CIMP marker methylation and mutations linked to methylation: BRAF, KRAS, GADD45A and the MLH1 -93G>A polymorphism. When available, normal colon and leukocyte DNA was tested for GADD45A mutations and germline MLH1 methylation. SNP array analysis was performed on a subset of tumors. Results We identified two cases (33 and 60 years with MLH1 germline promoter methylation. BRAF mutations were less frequent in colon cancer patients below 50 years relative to patients above 50 years (p-value: 0.044. CIMP-high was infrequent and related to BRAF mutations in patients below 50 years. In comparison with published controls the G>A polymorphism was associated with our cohort. Although similar distribution of the pathogenic A allele was observed in the patients with an age of onset above and below 50 years, the significance for the association was lost for the group under 50 years. GADD45A sequencing yielded an unclassified variant. Tumors from both age groups showed infrequent copy number changes and loss-of-heterozygosity. Conclusion Somatic or germline GADD45A mutations did not explain sporadic MSI-H colon cancer. Although germline MLH1 methylation was found in two individuals, locus-specific somatic MLH1 hypermethylation explained the majority of sporadic early onset MSI-H colon cancer cases. Our data do not suggest an intrinsic tendency for CpG island hypermethylation in these early onset MSI-H tumors other than through

  6. Isolated Loss of PMS2 Immunohistochemical Expression is Frequently Caused by Heterogenous MLH1 Promoter Hypermethylation in Lynch Syndrome Screening for Endometrial Cancer Patients.

    Science.gov (United States)

    Kato, Aya; Sato, Naoki; Sugawara, Tae; Takahashi, Kazue; Kito, Masahiko; Makino, Kenichi; Sato, Toshiharu; Shimizu, Dai; Shirasawa, Hiromistu; Miura, Hiroshi; Sato, Wataru; Kumazawa, Yukiyo; Sato, Akira; Kumagai, Jin; Terada, Yukihiro

    2016-06-01

    Lynch syndrome (LS) is an autosomal-dominant inherited disorder mainly caused by a germline mutation in the DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6, and PMS2) and is associated with increased risk for various cancers, particularly colorectal cancer and endometrial cancer (EC). Women with LS account for 2% to 6% of EC patients; it is clinically important to identify LS in such individuals for predicting and/or preventing additional LS-associated cancers. PMS2 germline mutation (PMS2-LS) is the rarest contribution to LS etiology among the 4 LS-associated MMR germline mutations, and its detection is complicated. Therefore, prudent screening for PMS2-LS is important as it leads to an efficient LS identification strategy. Immunohistochemistry is recommended as a screening method for LS in EC. Isolated loss of PMS2 (IL-PMS2) expression is caused not only by PMS2-LS but also by MLH1 germline mutation or MLH1 promoter hypermethylation (MLH-PHM). This study aimed to determine the association between MLH1-PHM and IL-PMS2 to avoid inappropriate genetic analysis. We performed MLH1 methylation analysis and MLH1/PMS2 germline mutation testing on the IL-PMS2 cases. By performing MMR-immunohistochemistry on 360 unselected ECs, we could select 8 (2.2%) cases as IL-PMS2. Heterogenous MLH1 staining and MLH1-PHM were detected in 4 of 8 (50%) IL-PMS2 tumors. Of the 5 IL-PMS2 patients who underwent genetic analysis, 1 had PMS2 germline mutation with normal MLH1 expression (without MLH1-PHM), and no MLH1 germline mutation was detected. We suggest that MLH1 promoter methylation analysis for IL-PMS2 EC should be performed to exclude sporadic cases before further PMS2 genetic testing.

  7. Association between promoter methylation of MLH1 and MSH2 and reactive oxygen species in oligozoospermic men-A pilot study.

    Science.gov (United States)

    Gunes, S; Agarwal, A; Henkel, R; Mahmutoglu, A M; Sharma, R; Esteves, S C; Aljowair, A; Emirzeoglu, D; Alkhani, A; Pelegrini, L; Joumah, A; Sabanegh, E

    2018-04-01

    MLH1 and MSH2 are important genes for DNA mismatch repair and crossing over during meiosis and are implicated in male infertility. Therefore, the methylation patterns of the DNA mismatch repair genes MLH1 and MSH2 in oligozoospermic males were investigated. Ten oligozoospermic patients and 29 normozoospermic donors were analysed. Methylation profiles of the MLH1 and MSH2 promotors were analysed. In addition, sperm motility and seminal reactive oxygen species (ROS) were recorded. Receiver operating characteristic (ROC) analysis was conducted to determine the accuracy of the DNA methylation status of MLH1 and MSH2 to distinguish between oligozoospermic and normozoospermic men. In oligozoospermic men, MLH1 was significantly (p = .0013) more methylated compared to normozoospermic men. Additionally, there was a significant positive association (r = .384; p = .0159) between seminal ROS levels and MLH1 methylation. Contrary, no association between MSH2 methylation and oligozoospermia was found. ROC curve analysis for methylation status of MLH1 was significant (p = .0275) with an area under the curve of 61.1%, a sensitivity of 22.2% and a specificity of 100.0%. This pilot study indicates oligozoospermic patients have more methylation of MLH1 than normozoospermic patients. Whether hypermethylation of the MLH1 promoter plays a role in repairing relevant mismatches of sperm DNA strands in idiopathic oligozoospermia warrants further investigation. © 2017 Blackwell Verlag GmbH.

  8. Endometrial tumour BRAF mutations and MLH1 promoter methylation as predictors of germline mismatch repair gene mutation status: a literature review.

    Science.gov (United States)

    Metcalf, Alexander M; Spurdle, Amanda B

    2014-03-01

    Colorectal cancer (CRC) that displays high microsatellite instability (MSI-H) can be caused by either germline mutations in mismatch repair (MMR) genes, or non-inherited transcriptional silencing of the MLH1 promoter. A correlation between MLH1 promoter methylation, specifically the 'C' region, and BRAF V600E status has been reported in CRC studies. Germline MMR mutations also greatly increase risk of endometrial cancer (EC), but no systematic review has been undertaken to determine if these tumour markers may be useful predictors of MMR mutation status in EC patients. Endometrial cancer cohorts meeting review inclusion criteria encompassed 2675 tumours from 20 studies for BRAF V600E, and 447 tumours from 11 studies for MLH1 methylation testing. BRAF V600E mutations were reported in 4/2675 (0.1%) endometrial tumours of unknown MMR mutation status, and there were 7/823 (0.9%) total sequence variants in exon 11 and 27/1012 (2.7%) in exon 15. Promoter MLH1 methylation was not observed in tumours from 32 MLH1 mutation carriers, or for 13 MSH2 or MSH6 mutation carriers. MMR mutation-negative individuals with tumour MLH1 and PMS2 IHC loss displayed MLH1 methylation in 48/51 (94%) of tumours. We have also detailed specific examples that show the importance of MLH1 promoter region, assay design, and quantification of methylation. This review shows that BRAF mutations occurs so infrequently in endometrial tumours they can be discounted as a useful marker for predicting MMR-negative mutation status, and further studies of endometrial cohorts with known MMR mutation status are necessary to quantify the utility of tumour MLH1 promoter methylation as a marker of negative germline MMR mutation status in EC patients.

  9. Promoter hypermethylation of DNA repair genes MLH1 and MSH2 in adenocarcinomas and squamous cell carcinomas of the lung

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    A. Gomes

    2014-01-01

    Full Text Available Five years survival of lung cancer is 16%, significantly lower than in prostate (99.9%, breast (88.5% and colon (64.1% carcinomas. When diagnosed in the surgical stage it increases to 50% but this group only comprises 14–16% of the cases. DNA methylation has emerged as a potential cancer-specific biomarker. Hypermethylation of CpG islands located in the promoter regions of tumour suppressor genes is now firmly established as an important mechanism for gene inactivation.This retrospective study included 40 squamous cell carcinomas and 40 adenocarcinomas in various surgical TNM stages to define methylation profile and possible silencing of DNA repair genes – MLH1 and MSH2 – using Methylation-Specific PCR and protein expression by immunohistochemistry in tumoural tissue, preneoplastic lesions and respiratory epithelium with normal histological features.The protein expression of MLH1 and MSH2 genes, in the available preneoplastic lesions and in normal cylindrical respiratory epithelium appeared reduced. The frequency of promoter hypermethylation found on these DNA repair genes was elevated, with a higher prevalence of methylation of MLH1 gene in 72% of squamous cell carcinoma. The differences are not so obvious for MSH2 promoter hypermethylation. No correlation was found among the status of methylation, the protein expression and the clinicopathological characteristics.With a larger study, a better characterization of the hypermethylation status of neoplastic and preneoplastic lesions in small biopsies would be achieved, inherent to tumour histology, heterogeneity and preservation, and finally differences in the study population to elucidate other possible mechanisms of altered expression of the hMLH1 and hMSH. Resumo: A sobrevivência aos cinco anos no cancro do pulmão é de 16%, significativamente inferior que nos carcinomas na próstata (99,9%, mama (88,5% e cólon (64,1%. Quando diagnosticado na fase cir

  10. Promoter methylation of MLH1, PMS2, MSH2 and p16 is a phenomenon of advanced-stage HCCs.

    Science.gov (United States)

    Hinrichsen, Inga; Kemp, Matthias; Peveling-Oberhag, Jan; Passmann, Sandra; Plotz, Guido; Zeuzem, Stefan; Brieger, Angela

    2014-01-01

    Epigenetic silencing of tumour suppressor genes has been observed in various cancers. Looking at hepatocellular carcinoma (HCC) specific protein silencing was previously demonstrated to be associated with the Hepatitis C virus (HCV). However, the proposed HCV dependent promoter methylation of DNA mismatch repair (MMR) genes and thereby enhanced progression of hepatocarcinogenesis has been the subject of controversial discussion. We investigated promoter methylation pattern of the MMR genes MLH1, MSH2 and PMS2 as well as the cyclin-dependent kinase inhibitor 2A gene (p16) in 61 well characterized patients with HCCs associated with HCV, Hepatitis B virus infection or alcoholic liver disease. DNA was isolated from formalin-fixed, paraffin-embedded tumour and non-tumour adjacent tissue and analysed by methylation-specific PCR. Moreover, microsatellite analysis was performed in tissues showing methylation in MMR gene promoters. Our data demonstrated that promoter methylation of MLH1, MSH2, PMS2 and p16 is present among all considered HCCs. Hereby, promoter silencing was detectable more frequently in advanced-stage HCCs than in low-stage ones. However, there was no significant correlation between aberrant DNA methylation of MMR genes or p16 and HCV infection in related HCC specimens. In summary, we show that promoter methylation of essential MMR genes and p16 is detectable in HCCs most dominantly in pT3 stage tumour cases. Since loss of MMR proteins was previously described to be not only responsible for tumour development but also for chemotherapy resistance, the knowledge of mechanisms jointly responsible for HCC progression might enable significant improvement of individual HCC therapy in the future.

  11. Promoter methylation of MLH1, PMS2, MSH2 and p16 is a phenomenon of advanced-stage HCCs.

    Directory of Open Access Journals (Sweden)

    Inga Hinrichsen

    Full Text Available Epigenetic silencing of tumour suppressor genes has been observed in various cancers. Looking at hepatocellular carcinoma (HCC specific protein silencing was previously demonstrated to be associated with the Hepatitis C virus (HCV. However, the proposed HCV dependent promoter methylation of DNA mismatch repair (MMR genes and thereby enhanced progression of hepatocarcinogenesis has been the subject of controversial discussion. We investigated promoter methylation pattern of the MMR genes MLH1, MSH2 and PMS2 as well as the cyclin-dependent kinase inhibitor 2A gene (p16 in 61 well characterized patients with HCCs associated with HCV, Hepatitis B virus infection or alcoholic liver disease. DNA was isolated from formalin-fixed, paraffin-embedded tumour and non-tumour adjacent tissue and analysed by methylation-specific PCR. Moreover, microsatellite analysis was performed in tissues showing methylation in MMR gene promoters. Our data demonstrated that promoter methylation of MLH1, MSH2, PMS2 and p16 is present among all considered HCCs. Hereby, promoter silencing was detectable more frequently in advanced-stage HCCs than in low-stage ones. However, there was no significant correlation between aberrant DNA methylation of MMR genes or p16 and HCV infection in related HCC specimens. In summary, we show that promoter methylation of essential MMR genes and p16 is detectable in HCCs most dominantly in pT3 stage tumour cases. Since loss of MMR proteins was previously described to be not only responsible for tumour development but also for chemotherapy resistance, the knowledge of mechanisms jointly responsible for HCC progression might enable significant improvement of individual HCC therapy in the future.

  12. Promoter hypermethylation of CDKN2A, MGMT, MLH1, and DAPK genes in laryngeal squamous cell carcinoma and their associations with clinical profiles of the patients.

    Science.gov (United States)

    Pierini, Stefano; Jordanov, Stanislav H; Mitkova, Atanaska V; Chalakov, Ivan J; Melnicharov, Mincho B; Kunev, Kuncho V; Mitev, Vanio I; Kaneva, Radka P; Goranova, Teodora E

    2014-08-01

    Laryngeal squamous cell carcinoma (laryngeal SCC) is a frequently occurring cancer of the head and neck area. Epigenetic changes of tumor-related genes contribute to its genesis and progression. We assessed promoter methylation status of the selected genes (CDKN2A, MGMT, MLH1, and DAPK) using methylation-sensitive high resolution melting (MS-HRM) in 100 patients with laryngeal SCC and studied the correlations with clinical characteristics. The prevalence of promoter methylation in MGMT, CDKN2A, MLH1, and DAPK was 59 of 97 (60.8%), 46 of 97 (47.4%), 45 of 97 (46.4%), and 41 of 97 patients (42.3%), respectively. Significantly increased methylation of CDKN2A was observed in heavy smokers. Epigenetic inactivation of CDKN2A and MLH1 were found to be associated with lymph node involvement. An inverse correlation was present between MLH1 methylation and alcohol consumption. Our results strongly suggest that deregulation of p16-associated, and MLH1-associated pathways, because of promoter hypermethylation, is associated with increased cancer cell migration, tumor invasiveness, and, thus, aggressive phenotype. Copyright © 2013 Wiley Periodicals, Inc.

  13. Diversity of genetic events associated with MLH1 promoter methylation in Lynch syndrome families with heritable constitutional epimutation.

    Science.gov (United States)

    Leclerc, Julie; Flament, Cathy; Lovecchio, Tonio; Delattre, Lucie; Ait Yahya, Emilie; Baert-Desurmont, Stéphanie; Burnichon, Nelly; Bronner, Myriam; Cabaret, Odile; Lejeune, Sophie; Guimbaud, Rosine; Morin, Gilles; Mauillon, Jacques; Jonveaux, Philippe; Laurent-Puig, Pierre; Frébourg, Thierry; Porchet, Nicole; Buisine, Marie-Pierre

    2018-04-12

    PurposeConstitutional epimutations are an alternative to genetic mutations in the etiology of genetic diseases. Some of these epimutations, termed secondary, correspond to the epigenetic effects of cis-acting genetic defects transmitted to the offspring following a Mendelian inheritance pattern. In Lynch syndrome, a few families with such apparently heritable MLH1 epimutations have been reported so far.MethodsWe designed a long-range polymerase chain reaction next-generation sequencing strategy to screen MLH1 entire gene and applied it to 4 French families with heritable epimutations and 10 additional patients with no proven transmission of their epimutations.ResultsThis strategy successfully detected the insertion of an Alu element in MLH1 coding sequence in one family. Two previously unreported MLH1 variants were also identified in other epimutation carriers: a nucleotide substitution within intron 1 and a single-nucleotide deletion in the 5'-UTR. Detection of a partial MLH1 duplication in another family required multiplex ligation-dependent probe amplification technology. We demonstrated the segregation of these variants with MLH1 methylation and studied the functional consequences of these defects on transcription.ConclusionThis is the largest cohort of patients with MLH1 secondary epimutations associated with a broad spectrum of genetic defects. This study provides further insight into the complexity of molecular mechanisms leading to secondary epimutations.GENETICS in MEDICINE advance online publication, 12 April 2018; doi:10.1038/gim.2018.47.

  14. Correlation of MLH1 and MGMT expression and promoter methylation with genomic instability in patients with thyroid carcinoma

    International Nuclear Information System (INIS)

    Santos, Juliana Carvalho; Bastos, André Uchimura; Cerutti, Janete Maria; Ribeiro, Marcelo Lima

    2013-01-01

    Gene silencing of the repair genes MLH1 and MGMT was shown to be a mechanism underlying the development of microsatellite instability (MSI), a phenotype frequently associated with various human malignancies. Recently, aberrant methylation of MLH1, MGMT and MSI were shown to be associated with mutations in genes such as BRAF, RAS and IDH1 in colon and brain tumours. Little is known about the methylation status of MLH1 and MGMT in thyroid tumours and its association with MSI and mutational status. In a series of 96 thyroid tumours whose mutational profiles of BRAF, IDH1 and NRAS mutations and RET/PTC were previously determined, we investigated MLH1 and MGMT expression and methylation status by qPCR and methylation-specific PCR after bisulphite treatment, respectively. MSI was determined by PCR using seven standard microsatellite markers. Samples with point mutations (BRAF, IDH1 and NRAS) show a decrease in MLH1 expression when compared to negative samples. Additionally, malignant lesions show a higher MSI pattern than benign lesions. The MSI phenotype was also associated with down-regulation of MLH1. The results of this study allow us to conclude that low expression of MLH1 is associated with BRAF V600E mutations, RET/PTC rearrangements and transitions (IDH1 and NRAS) in patients with thyroid carcinoma. In addition, a significant relationship between MSI status and histological subtypes was found

  15. Efficient molecular screening of Lynch syndrome by specific 3' promoter methylation of the MLH1 or BRAF mutation in colorectal cancer with high-frequency microsatellite instability.

    Science.gov (United States)

    Nakagawa, Hitoshi; Nagasaka, Takeshi; Cullings, Harry M; Notohara, Kenji; Hoshijima, Naoko; Young, Joanne; Lynch, Henry T; Tanaka, Noriaki; Matsubara, Nagahide

    2009-06-01

    It is sometimes difficult to diagnose Lynch syndrome by the simple but strict clinical criteria, or even by the definitive genetic testing for causative germline mutation of mismatch repair genes. Thus, some practical and efficient screening strategy to select highly possible Lynch syndrome patients is exceedingly desirable. We performed a comprehensive study to evaluate the methylation status of whole MLH1 promoter region by direct bisulfite sequencing of the entire MLH1 promoter regions on Lynch and non-Lynch colorectal cancers (CRCs). Then, we established a convenient assay to detect methylation in key CpG islands responsible for the silencing of MLH1 expression. We studied the methylation status of MLH1 as well as the CpG island methylator phenotype (CIMP) and immunohistochemical analysis of mismatch repair proteins on 16 cases of Lynch CRC and 19 cases of sporadic CRCs with high-frequency microsatellite instability (MSI-H). Sensitivity to detect Lynch syndrome by MLH1 (CCAAT) methylation was 88% and the specificity was 84%. Positive likelihood ratio (PLR) was 5.5 and negative likelihood ratio (NLR) was 0.15. Sensitivity by mutational analysis of BRAF was 100%, specificity was 84%, PLR was 6.3 and NLR was zero. By CIMP analysis; sensitivity was 88%, specificity was 79%, PLR was 4.2, and NLR was 0.16. BRAF mutation or MLH1 methylation analysis combined with MSI testing could be a good alternative to screen Lynch syndrome patients in a cost effective manner. Although the assay for CIMP status also showed acceptable sensitivity and specificity, it may not be practical because of its rather complicated assay.

  16. Estrogen enhances mismatch repair by induction of MLH1 expression via estrogen receptor-β.

    Science.gov (United States)

    Lu, Jun-Yu; Jin, Peng; Gao, Wei; Wang, De-Zhi; Sheng, Jian-Qiu

    2017-06-13

    Epidemiological data demonstrated that hormone replace treatment has protective effect against colorectal cancer (CRC). Our previous studies showed that this effect may be associated with DNA mismatch repair. This study aims to investigate the mechanism of estrogen induction of MLH1, and whether colorectal tumor proliferation can be inhibited through induction of MLH1 by estrogen signal pathway. Human CRC cell lines were used to examine the regulation of MLH1 expression by over-expression and depletion of estrogen receptor-α (ERα) and estrogen receptor-β (ERβ), under the treatment with 17β-estradiol or β-Estradiol 6-(O-carboxy-methyl)oxime:BSA, followed by a real-time Q-PCR and Western blotting analysis. Luciferase reporter and chromatin immunoprecipitation assays were used to identify the estrogen response elements in the proximal promoter of MLH1 gene. Then, the influence of estrogen-induced MLH1 on CRC tumor growth were determined in vitro and in vivo. We found that mismatch repair ability and microsatellite stability of cells were enhanced by estrogen via induction of MLH1 expression, which was mediated by ERβ, through a transcriptional activation process. Furthermore, we identified that ERβ exerted an inhibitory effect on CRC tumor proliferation in vitro and in vivo, combined with 5-FU, through up-regulation of MLH1 expression. Finally, we concluded that estrogen enhances mismatch repair ability and tumor inhibition effect in vitro and in vivo, via induction of MLH1 expression mediated by ERβ.

  17. Epigenetic Silencing of the MLH1 Promoter in Relation to the Development of Gastric Cancer and its use as a Biomarker for Patients with Microsatellite Instability: a Systematic Analysis.

    Science.gov (United States)

    Hu, Guimei; Qin, Lijun; Zhang, Xinjun; Ye, Guoliang; Huang, Tao

    2018-01-01

    Human mutL homolog 1 (MLH1) promoter methylation was reported in gastric cancer (GC). This study determined the clinicopathological, prognostic, and diagnostic effects of MLH1 promoter methylation in GC. The combined odds ratio (OR) or hazard ratio (HR) and their corresponding 95% confidence intervals (95% CI) were calculated. The pooled sensitivity, specificity, and area under the curve (AUC) were analyzed. A total of 4654 GC patients and 3669 non-malignant controls were identified in this systematic analysis. MLH1 promoter methylation was significantly higher in GC samples than in gastric adenomas, chronic gastritis, adjacent tissues, normal gastric mucosa, and normal healthy blood samples, but it exhibited a similar frequency in GC vs. intestinal metaplasia and dysplasia samples. MLH1 promoter methylation correlated with age and microsatellite instability (MSI), but it was not associated with gender, H. pylori infection, smoking, drinking behaviors, pathological histology, tumor differentiation, clinical stage, lymph node status, distant metastasis, or overall survival of GC. MLH1 promoter methylation exhibited a poor sensitivity value (MLH1 promoter methylation in GC with MSI vs. GC with microsatellite stability (MSS) samples were 0.64, 0.96, and 0.90, respectively. Our results suggest that the detection of MLH1 promoter methylation may be a potential prognostic biomarker for GC patients with MSI. © 2018 The Author(s). Published by S. Karger AG, Basel.

  18. Loss of mutL homolog-1 (MLH1) expression promotes acquisition of oncogenic and inhibitor-resistant point mutations in tyrosine kinases.

    Science.gov (United States)

    Springuel, Lorraine; Losdyck, Elisabeth; Saussoy, Pascale; Turcq, Béatrice; Mahon, François-Xavier; Knoops, Laurent; Renauld, Jean-Christophe

    2016-12-01

    Genomic instability drives cancer progression by promoting genetic abnormalities that allow for the multi-step clonal selection of cells with growth advantages. We previously reported that the IL-9-dependent TS1 cell line sequentially acquired activating substitutions in JAK1 and JAK3 upon successive selections for growth factor independent and JAK inhibitor-resistant cells, suggestive of a defect in mutation avoidance mechanisms. In the first part of this paper, we discovered that the gene encoding mutL homolog-1 (MLH1), a key component of the DNA mismatch repair system, is silenced by promoter methylation in TS1 cells. By means of stable ectopic expression and RNA interference methods, we showed that the high frequencies of growth factor-independent and inhibitor-resistant cells with activating JAK mutations can be attributed to the absence of MLH1 expression. In the second part of this paper, we confirm the clinical relevance of our findings by showing that chronic myeloid leukemia relapses upon ABL-targeted therapy correlated with a lower expression of MLH1 messenger RNA. Interestingly, the mutational profile observed in our TS1 model, characterized by a strong predominance of T:A>C:G transitions, was identical to the one described in the literature for primitive cells derived from chronic myeloid leukemia patients. Taken together, our observations demonstrate for the first time a causal relationship between MLH1-deficiency and incidence of oncogenic point mutations in tyrosine kinases driving cell transformation and acquired resistance to kinase-targeted cancer therapies.

  19. Epigenetic Silencing of the MLH1 Promoter in Relation to the Development of Gastric Cancer and its use as a Biomarker for Patients with Microsatellite Instability: a Systematic Analysis

    Directory of Open Access Journals (Sweden)

    Guimei Hu

    2018-01-01

    Full Text Available Background/Aims: Human mutL homolog 1 (MLH1 promoter methylation was reported in gastric cancer (GC. This study determined the clinicopathological, prognostic, and diagnostic effects of MLH1 promoter methylation in GC. Methods: The combined odds ratio (OR or hazard ratio (HR and their corresponding 95% confidence intervals (95% CI were calculated. The pooled sensitivity, specificity, and area under the curve (AUC were analyzed. Results: A total of 4654 GC patients and 3669 non-malignant controls were identified in this systematic analysis. MLH1 promoter methylation was significantly higher in GC samples than in gastric adenomas, chronic gastritis, adjacent tissues, normal gastric mucosa, and normal healthy blood samples, but it exhibited a similar frequency in GC vs. intestinal metaplasia and dysplasia samples. MLH1 promoter methylation correlated with age and microsatellite instability (MSI, but it was not associated with gender, H. pylori infection, smoking, drinking behaviors, pathological histology, tumor differentiation, clinical stage, lymph node status, distant metastasis, or overall survival of GC. MLH1 promoter methylation exhibited a poor sensitivity value (< 0.5 in patients with GC compared with adjacent tissues, gastric adenomas, chronic gastritis, normal gastric mucosa, and normal healthy blood samples. The pooled sensitivity, specificity, and AUC of MLH1 promoter methylation in GC with MSI vs. GC with microsatellite stability (MSS samples were 0.64, 0.96, and 0.90, respectively. Conclusions: Our results suggest that the detection of MLH1 promoter methylation may be a potential prognostic biomarker for GC patients with MSI.

  20. Contribution of MLH1 constitutional methylation for Lynch syndrome diagnosis in patients with tumor MLH1 downregulation.

    Science.gov (United States)

    Pinto, Diana; Pinto, Carla; Guerra, Joana; Pinheiro, Manuela; Santos, Rui; Vedeld, Hege Marie; Yohannes, Zeremariam; Peixoto, Ana; Santos, Catarina; Pinto, Pedro; Lopes, Paula; Lothe, Ragnhild; Lind, Guro Elisabeth; Henrique, Rui; Teixeira, Manuel R

    2018-02-01

    Constitutional epimutation of the two major mismatch repair genes, MLH1 and MSH2, has been identified as an alternative mechanism that predisposes to the development of Lynch syndrome. In the present work, we aimed to investigate the prevalence of MLH1 constitutional methylation in colorectal cancer (CRC) patients with abnormal expression of the MLH1 protein in their tumors. In a series of 38 patients who met clinical criteria for Lynch syndrome genetic testing, with loss of MLH1 expression in the tumor and with no germline mutations in the MLH1 gene (35/38) or with tumors presenting the BRAF p.Val600Glu mutation (3/38), we screened for constitutional methylation of the MLH1 gene promoter using methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) in various biological samples. We found four (4/38; 10.5%) patients with constitutional methylation in the MLH1 gene promoter. RNA studies demonstrated decreased MLH1 expression in the cases with constitutional methylation when compared with controls. We could infer the mosaic nature of MLH1 constitutional hypermethylation in tissues originated from different embryonic germ layers, and in one family we could show that it occurred de novo. We conclude that constitutional MLH1 methylation occurs in a significant proportion of patients who have loss of MLH1 protein expression in their tumors and no MLH1 pathogenic germline mutation. Furthermore, we provide evidence that MLH1 constitutional hypermethylation is the molecular mechanism behind about 3% of Lynch syndrome families diagnosed in our institution, especially in patients with early onset or multiple primary tumors without significant family history. © 2018 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

  1. Promoter methylation and expression of MGMT and the DNA mismatch repair genes MLH1, MSH2, MSH6 and PMS2 in paired primary and recurrent glioblastomas.

    Science.gov (United States)

    Felsberg, Jörg; Thon, Niklas; Eigenbrod, Sabina; Hentschel, Bettina; Sabel, Michael C; Westphal, Manfred; Schackert, Gabriele; Kreth, Friedrich Wilhelm; Pietsch, Torsten; Löffler, Markus; Weller, Michael; Reifenberger, Guido; Tonn, Jörg C

    2011-08-01

    Epigenetic silencing of the O(6) -methylguanine-DNA methyltransferase (MGMT) gene promoter is associated with prolonged survival in glioblastoma patients treated with temozolomide (TMZ). We investigated whether glioblastoma recurrence is associated with changes in the promoter methylation status and the expression of MGMT and the DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6 and PMS2 in pairs of primary and recurrent glioblastomas of 80 patients, including 64 patients treated with radiotherapy and TMZ after the first operation. Among the primary tumors, the MGMT promoter was methylated in 31 patients and unmethylated in 49 patients. In 71 patients (89%), the MGMT promoter methylation status of the primary tumor was retained at recurrence. MGMT promoter methylation, but not MGMT protein expression, was associated with longer progression-free survival, overall survival and postrecurrence survival (PRS). Moreover, PRS was increased under salvage chemotherapy. Investigation of primary and recurrent glioblastomas of 43 patients did not identify promoter methylation in any of the four MMR genes. However, recurrent glioblastomas demonstrated significantly lower MSH2, MSH6 and PMS2 protein expression as detected by immunohistochemistry. In conclusion, reduced expression of MMR proteins, but not changes in MGMT promoter methylation, is characteristic of glioblastomas recurring after the current standards of care. Copyright © 2011 UICC.

  2. Cancer-Predicting Gene Expression Changes in Colonic Mucosa of Western Diet Fed Mlh1 +/- Mice

    Science.gov (United States)

    Dermadi Bebek, Denis; Valo, Satu; Reyhani, Nima; Ollila, Saara; Päivärinta, Essi; Peltomäki, Päivi; Mutanen, Marja; Nyström, Minna

    2013-01-01

    Colorectal cancer (CRC) is the second most common cause of cancer-related deaths in the Western world and interactions between genetic and environmental factors, including diet, are suggested to play a critical role in its etiology. We conducted a long-term feeding experiment in the mouse to address gene expression and methylation changes arising in histologically normal colonic mucosa as putative cancer-predisposing events available for early detection. The expression of 94 growth-regulatory genes previously linked to human CRC was studied at two time points (5 weeks and 12 months of age) in the heterozygote Mlh1 +/- mice, an animal model for human Lynch syndrome (LS), and wild type Mlh1 +/+ littermates, fed by either Western-style (WD) or AIN-93G control diet. In mice fed with WD, proximal colon mucosa, the predominant site of cancer formation in LS, exhibited a significant expression decrease in tumor suppressor genes, Dkk1, Hoxd1, Slc5a8, and Socs1, the latter two only in the Mlh1 +/- mice. Reduced mRNA expression was accompanied by increased promoter methylation of the respective genes. The strongest expression decrease (7.3 fold) together with a significant increase in its promoter methylation was seen in Dkk1, an antagonist of the canonical Wnt signaling pathway. Furthermore, the inactivation of Dkk1 seems to predispose to neoplasias in the proximal colon. This and the fact that Mlh1 which showed only modest methylation was still expressed in both Mlh1 +/- and Mlh1 +/+ mice indicate that the expression decreases and the inactivation of Dkk1 in particular is a prominent early marker for colon oncogenesis. PMID:24204690

  3. Cancer-predicting gene expression changes in colonic mucosa of Western diet fed Mlh1+/- mice.

    Directory of Open Access Journals (Sweden)

    Marjaana Pussila

    Full Text Available Colorectal cancer (CRC is the second most common cause of cancer-related deaths in the Western world and interactions between genetic and environmental factors, including diet, are suggested to play a critical role in its etiology. We conducted a long-term feeding experiment in the mouse to address gene expression and methylation changes arising in histologically normal colonic mucosa as putative cancer-predisposing events available for early detection. The expression of 94 growth-regulatory genes previously linked to human CRC was studied at two time points (5 weeks and 12 months of age in the heterozygote Mlh1(+/- mice, an animal model for human Lynch syndrome (LS, and wild type Mlh1(+/+ littermates, fed by either Western-style (WD or AIN-93G control diet. In mice fed with WD, proximal colon mucosa, the predominant site of cancer formation in LS, exhibited a significant expression decrease in tumor suppressor genes, Dkk1, Hoxd1, Slc5a8, and Socs1, the latter two only in the Mlh1(+/- mice. Reduced mRNA expression was accompanied by increased promoter methylation of the respective genes. The strongest expression decrease (7.3 fold together with a significant increase in its promoter methylation was seen in Dkk1, an antagonist of the canonical Wnt signaling pathway. Furthermore, the inactivation of Dkk1 seems to predispose to neoplasias in the proximal colon. This and the fact that Mlh1 which showed only modest methylation was still expressed in both Mlh1(+/- and Mlh1(+/+ mice indicate that the expression decreases and the inactivation of Dkk1 in particular is a prominent early marker for colon oncogenesis.

  4. Distinct features between MLH1-methylated and unmethylated colorectal carcinomas with the CpG island methylator phenotype: implications in the serrated neoplasia pathway.

    Science.gov (United States)

    Kim, Jung Ho; Bae, Jeong Mo; Cho, Nam-Yun; Kang, Gyeong Hoon

    2016-03-22

    The presence or absence of MLH1 methylation may critically affect the heterogeneity of colorectal carcinoma (CRC) with the CpG island methylator phenotype (CIMP). Here, we investigated the differential characteristics of CIMP-high (CIMP-H) CRCs according to MLH1 methylation status. To further confirm the MLH1-dependent features in CIMP-H CRC, an independent analysis was performed using data from The Cancer Genome Atlas (TCGA). In our CIMP-H CRC samples, MLH1-methylated tumors were characterized by older patient age, proximal colonic location, mucinous histology, intense lymphoid reactions, RUNX3/SOCS1 promoter methylation, BRAF mutations, and microsatellite instability-high (MSI-H) status. By contrast, MLH1-unmethylated tumors were associated with earlier age of onset, increased distal colorectal localization, adverse pathologic features, and KRAS mutations. In the TCGA dataset, the MLH1-silenced CIMP-H CRC demonstrated proximal location, MSI-H status, hypermutated phenotype, and frequent BRAF mutations, but the MLH1-non-silenced CIMP-H CRC was significantly associated with high frequencies of KRAS and APC mutations. In conclusion, the differential nature of CIMP-H CRCs depends primarily on the MLH1 methylation status. Based on the current knowledge, the sessile serrated adenoma/polyp may be the major precursor of MLH1-methylated CIMP-H CRCs, whereas MLH1-unmethylated CIMP-H CRCs may develop predominantly from KRAS-mutated traditional serrated adenomas and less commonly from BRAF-mutated traditional serrated adenomas and/or sessile serrated adenomas/polyps.

  5. MLH1 constitutional and somatic methylation in patients with MLH1 negative tumors fulfilling the revised Bethesda criteria.

    Science.gov (United States)

    Crucianelli, Francesca; Tricarico, Rossella; Turchetti, Daniela; Gorelli, Greta; Gensini, Francesca; Sestini, Roberta; Giunti, Laura; Pedroni, Monica; Ponz de Leon, Maurizio; Civitelli, Serenella; Genuardi, Maurizio

    2014-10-01

    Lynch syndrome (LS) is a tumor predisposing condition caused by constitutional defects in genes coding for components of the mismatch repair (MMR) apparatus. While hypermethylation of the promoter of the MMR gene MLH1 occurs in about 15% of colorectal cancer samples, it has also been observed as a constitutional alteration, in the absence of DNA sequence mutations, in a small number of LS patients. In order to obtain further insights on the phenotypic characteristics of MLH1 epimutation carriers, we investigated the somatic and constitutional MLH1 methylation status of 14 unrelated subjects with a suspicion of LS who were negative for MMR gene constitutional mutations and whose tumors did not express the MLH1 protein. A novel case of constitutional MLH1 epimutation was identified. This patient was affected with multiple primary tumors, including breast cancer, diagnosed starting from the age of 55 y. Investigation of her offspring by allele specific expression revealed that the epimutation was not stable across generations. We also found MLH1 hypermethylation in cancer samples from 4 additional patients who did not have evidence of constitutional defects. These patients had some characteristics of LS, namely early age at onset and/or positive family history, raising the possibility of genetic influences in the establishment of somatic MLH1 methylation.

  6. MLH1-rheMac hereditary nonpolyposis colorectal cancer syndrome in rhesus macaques.

    Science.gov (United States)

    Brammer, David W; Gillespie, Patrick J; Tian, Mei; Young, Daniel; Raveendran, Muthuswamy; Williams, Lawrence E; Gagea, Mihai; Benavides, Fernando J; Perez, Carlos J; Broaddus, Russell R; Bernacky, Bruce J; Barnhart, Kirstin F; Alauddin, Mian M; Bhutani, Manoop S; Gibbs, Richard A; Sidman, Richard L; Pasqualini, Renata; Arap, Wadih; Rogers, Jeffrey; Abee, Christian R; Gelovani, Juri G

    2018-03-13

    Over the past two decades, 33 cases of colonic adenocarcinomas have been diagnosed in rhesus macaques ( Macaca mulatta ) at the nonhuman primate colony of the Keeling Center for Comparative Medicine and Research at The University of Texas MD Anderson Cancer Center. The distinctive feature in these cases, based on PET/computed tomography (CT) imaging, was the presence of two or three tumor lesions in different locations, including proximal to the ileocecal juncture, proximal to the hepatic flexure, and/or in the sigmoid colon. These colon carcinoma lesions selectively accumulated [ 18 F]fluorodeoxyglucose ([ 18 F]FDG) and [ 18 F]fluoroacetate ([ 18 F]FACE) at high levels, reflecting elevated carbohydrate and fatty acid metabolism in these tumors. In contrast, the accumulation of [ 18 F]fluorothymidine ([ 18 F]FLT) was less significant, reflecting slow proliferative activity in these tumors. The diagnoses of colon carcinomas were confirmed by endoscopy. The expression of MLH1, MSH2, and MSH6 proteins and the degree of microsatellite instability (MSI) was assessed in colon carcinomas. The loss of MLH1 protein expression was observed in all tumors and was associated with a deletion mutation in the MLH1 promoter region and/or multiple single-nucleotide polymorphism (SNP) mutations in the MLH1 gene. All tumors exhibited various degrees of MSI. The pedigree analysis of this rhesus macaque population revealed several clusters of affected animals related to each other over several generations, suggesting an autosomal dominant transmission of susceptibility for colon cancer. The newly discovered hereditary nonpolyposis colorectal cancer syndrome in rhesus macaques, termed MLH1 -rheMac, may serve as a model for development of novel approaches to diagnosis and therapy of Lynch syndrome in humans. Copyright © 2018 the Author(s). Published by PNAS.

  7. Isolated loss of PMS2 immunohistochemical expression is frequently caused by heterogeneous MLH1 promoter hypermethylation in Lynch syndrome screening for endometrial cancer patients

    OpenAIRE

    Kato, Aya; Sato, Naoki; Sugawara, Tae; Takahashi, Kazue; Kito, Masahiko; Makino, Kenichi; Sato, Toshiharu; Shimizu, Dai; Shirasawa, Hiromitu; Miura, Hiroshi; Sato, Wataru; Kumazawa, Yukiyo; Sato, Akira; Kumagai, Jin; Terada, Yukihiro

    2016-01-01

    Lynch syndrome (LS) is an autosomal dominant inherited disorder mainly caused by a germline mutation in the DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6, PMS2) and is associated with increased risk of various cancers, particularly colorectal cancer and endometrial cancer (EC). Women with LS account for 2–6% of EC patients; it is clinically important to identify LS in such individuals for predicting and/or preventing additional LS-associated cancers. PMS2 germline mutation ...

  8. Disruption of a -35kb enhancer impairs CTCF binding and MLH1 expression in colorectal cells.

    Science.gov (United States)

    Liu, Qing; Thoms, Julie A; Nunez, Andrea C; Huang, Yizhou; Knezevic, Kathy; Packham, Deborah; Poulos, Rebecca C; Williams, Rachel; Beck, Dominik; Hawkins, Nicholas J; Ward, Robyn L; Wong, Jason W H; Hesson, Luke B; Sloane, Mathew A; Pimanda, John

    2018-06-13

    MLH1 is a major tumour suppressor gene involved in the pathogenesis of Lynch syndrome and various sporadic cancers. Despite their potential pathogenic importance, genomic regions capable of regulating MLH1 expression over long distances have yet to be identified. Here we use chromosome conformation capture (3C) to screen a 650-kb region flanking the MLH1 locus to identify interactions between the MLH1 promoter and distal regions in MLH1 expressing and non-expressing cells. Putative enhancers were functionally validated using luciferase reporter assays, chromatin immunoprecipitation and CRISPR-Cas9 mediated deletion of endogenous regions. To evaluate whether germline variants in the enhancer might contribute to impaired MLH1 expression in patients with suspected Lynch syndrome, we also screened germline DNA from a cohort of 74 patients with no known coding mutations or epimutations at the MLH1 promoter. A 1.8kb DNA fragment, 35kb upstream of the MLH1 transcription start site enhances MLH1 gene expression in colorectal cells. The enhancer was bound by CTCF and CRISPR-Cas9 mediated deletion of a core binding region impairs endogenous MLH1 expression. 5.4% of suspected Lynch syndrome patients have a rare single nucleotide variant (G>A; rs143969848; 2.5% in gnomAD European, non-Finnish) within a highly conserved CTCF binding motif, which disrupts enhancer activity in SW620 colorectal carcinoma cells. A CTCF bound region within the MLH1 -35 enhancer regulates MLH1 expression in colorectal cells and is worthy of scrutiny in future genetic screening strategies for suspected Lynch syndrome associated with loss of MLH1 expression. Copyright ©2018, American Association for Cancer Research.

  9. Finding the needle in a haystack: identification of cases of Lynch syndrome with MLH1 epimutation.

    Science.gov (United States)

    Hitchins, Megan P

    2016-07-01

    Constitutional epimutation of the DNA mismatch repair gene, MLH1, represents a minor cause of Lynch syndrome. MLH1 epimutations are characterized by the soma-wide distribution of methylation of a single allele of the MLH1 promoter accompanied by constitutive allelic loss of transcription. 'Primary' MLH1 epimutations, considered pure epigenetic defects, tend to arise de novo in patients without a family history or any apparent genetic mutation. These demonstrate non-Mendelian inheritance. 'Secondary' MLH1 epimutations have a genetic basis and have been linked to non-coding genetic alterations in the vicinity of MLH1. These demonstrate autosomal dominant inheritance. Despite convincing evidence of their role in causing Lynch-type cancers, routine screening for MLH1 epimutations has not been widely adopted. Complicating factors may include: the need to perform additional methylation-based testing beyond the standard genetic screening for a germline mutation; the lack of a consensus algorithm for the selection of patients warranting MLH1 epimutation testing; overlapping molecular pathology features of MLH1 methylation and loss of MLH1 expression with more prevalent sporadic MSI cancers; the rarity of MLH1 epimutation; the variable inter-generational inheritance patterns; and the cost-effectiveness of screening. Nevertheless, a positive molecular diagnosis of MLH1 epimutation is clinically important because carriers have a high personal risk of developing metachronous Lynch-type cancers, and their relatives may also be at risk of carriage. Extending existing universal and clinic-based screening algorithms for Lynch syndrome to include an additional arm of selection criteria for cases warranting MLH1 epimutation testing could provide a cost-effective means of diagnosing these cases.

  10. Concomitant mutation and epimutation of the MLH1 gene in a Lynch syndrome family.

    Science.gov (United States)

    Cini, Giulia; Carnevali, Ileana; Quaia, Michele; Chiaravalli, Anna Maria; Sala, Paola; Giacomini, Elisa; Maestro, Roberta; Tibiletti, Maria Grazia; Viel, Alessandra

    2015-04-01

    Lynch syndrome (LS) is an inherited predisposition cancer syndrome, typically caused by germline mutations in the mismatch repair genes MLH1, MSH2, MSH6 and PMS2. In the last years, a role for epimutations of the same genes has also been reported. MLH1 promoter methylation is a well known mechanism of somatic inactivation in tumors, and more recently, several cases of constitutional methylation have been identified. In four subjects affected by multiple tumors and belonging to a suspected LS family, we detected a novel secondary MLH1 gene epimutation. The methylation of MLH1 promoter was always linked in cis with a 997 bp-deletion (c.-168_c.116+713del), that removed exon 1 and partially involved the promoter of the same gene. Differently from cases with constitutional primary MLH1 inactivation, this secondary methylation was allele-specific and CpGs of the residual promoter region were totally methylated, leading to complete allele silencing. In the colon tumor of the proband, MLH1 and PMS2 expression was completely lost as a consequence of a pathogenic somatic point mutation (MLH1 c.199G>A, p.Gly67Arg) that also abrogated local methylation by destroying a CpG site. The evidences obtained highlight how MLH1 mutations and epimutations can reciprocally influence each other and suggest that an altered structure of the MLH1 locus results in epigenetic alteration. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Role of MLH1 methylation in esophageal cancer carcinogenesis and its clinical significance.

    Science.gov (United States)

    Li, Jinyun; Ye, Dong; Wang, Lei; Peng, Yingying; Li, Qun; Deng, Hongxia; Zhou, Chongchang

    2018-01-01

    The mutL homolog-1 ( MLH1 ) is a DNA mismatch repair gene and has been reported to be frequently methylated in numerous cancers. However, the association between MLH1 methylation and esophageal cancer (EC), as well as its clinical significance, remains unclear. Hence, we conducted a systematic meta-analysis based on 19 articles (including 1384 ECs, 345 premalignant lesions, and 1244 healthy controls). Our analysis revealed that the frequency of MLH1 methylation was significantly elevated during EC carcinogenesis. In addition, we observed that MLH1 promoter methylation was associated with age (odds ratio [OR]=1.79; 95% CI =1.20-2.66), advanced tumor grade (OR=3.7; 95% CI =2.37-5.77), lymph node metastasis (OR=2.65; 95% CI =1.81-3.88), distant metastasis (OR=7.60; 95% CI =1.23-47.19), advanced clinical stage (OR=4.46; 95% CI =2.88-6.91), and poor prognosis in EC patients (hazard ratio =1.64, 95% CI =1.00-2.69). The pooled sensitivity, specificity, and area under the curve of MLH1 methylation in EC patients versus healthy individuals were 0.15, 0.99, and 0.77, respectively. Our findings indicate that MLH1 methylation is involved in the carcinogenesis, progression, and metastasis of EC. Moreover, methylated MLH1 could be a potential diagnostic and prognostic biomarker for EC.

  12. MGMT and MLH1 methylation in Helicobacter pylori-infected children and adults.

    Science.gov (United States)

    Alvarez, Marisa C; Santos, Juliana C; Maniezzo, Nathália; Ladeira, Marcelo S; da Silva, Artur L C; Scaletsky, Isabel C A; Pedrazzoli, José; Ribeiro, Marcelo L

    2013-05-28

    To evaluate the association between Helicobacter pylori (H. pylori) infection and MLH1 and MGMT methylation and its relationship with microsatellite instability (MSI). The methylation status of the MLH1 and MGMT promoter region was analysed by methylation specific methylation-polymerase chain reaction (MSP-PCR) in gastric biopsy samples from uninfected or H. pylori-infected children (n = 50), from adults with chronic gastritis (n = 97) and from adults with gastric cancer (n = 92). MLH1 and MGMT mRNA expression were measured by real-time PCR and normalised to a constitutive gene (β actin). MSI analysis was performed by screening MSI markers at 4 loci (Bat-25, Bat-26, D17S250 and D2S123) with PCR; PCR products were analysed by single strand conformation polymorphism followed by silver staining. Statistical analyses were performed with either the χ(2) test with Yates continuity correction or Fisher's exact test, and statistical significance for expression analysis was assessed using an unpaired Student's t-test. Methylation was not detected in the promoter regions of MLH1 and MGMT in gastric biopsy samples from children, regardless of H. pylori infection status. The MGMT promoter was methylated in 51% of chronic gastritis adult patients and was associated with H. pylori infection (P MLH1 methylation frequencies among H. pylori-infected and non-infected chronic gastritis adult patients were 13% and 7%, respectively. We observed methylation of the MLH1 promoter (39%) and increased MSI levels (68%) in samples from gastric cancer patients in comparison to samples from H. pylori-infected adult chronic gastritis patients (P MLH1 and MGMT mRNA were significantly reduced in chronic gastritis samples that were also hypermethylated (P MLH1 methylation did not occur in earlier-stage H. pylori infections and thus might depend on the duration of infection.

  13. Constitutional MLH1 methylation presenting with colonic polyposis syndrome and not Lynch syndrome.

    Science.gov (United States)

    Kidambi, Trilokesh D; Blanco, Amie; Van Ziffle, Jessica; Terdiman, Jonathan P

    2016-04-01

    At least one-third of patients meeting clinical criteria for Lynch syndrome will have no germline mutation and constitutional epimutations leading to promoter methylation of MLH1 have been identified in a subset of these patients. We report the first case of constitutional MLH1 promoter methylation associated with a colonic polyposis syndrome in a 39 year-old man with a family history of colorectal cancer (CRC) and a personal history of 21 polyps identified over 8 years as well as the development of two synchronous CRCs over 16 months who was evaluated for a hereditary cancer syndrome. Immunohistochemistry (IHC) of multiple tumors showed absent MLH1 and PMS2 expression, though germline testing with Sanger sequencing and multiplex ligation-dependent probe amplification of these mismatch repair genes (MMR) genes was negative. A next generation sequencing panel of 29 genes also failed to identify a pathogenic mutation. Hypermethylation was identified in MLH1 intron 1 in tumor specimens along with buccal cells and peripheral white blood cells, confirming the diagnosis of constitutional MLH1 promoter methylation. This case highlights that constitutional MLH1 methylation should be considered in the differential diagnosis for a polyposis syndrome if IHC staining shows absent MMR gene expression.

  14. Ovarian metastasis from uveal melanoma with MLH1/PMS2 protein loss in a patient with germline MLH1 mutated Lynch syndrome: consequence or coincidence?

    Science.gov (United States)

    Lobo, João; Pinto, Carla; Freitas, Micaela; Pinheiro, Manuela; Vizcaino, Rámon; Oliva, Esther; Teixeira, Manuel R; Jerónimo, Carmen; Bartosch, Carla

    2017-03-01

    Currently, uveal melanoma is not considered within the Lynch syndrome tumor spectrum. However, there are studies suggesting a contribution of microsatellite instability in sporadic uveal melanoma tumorigenesis. We report a 45-year-old woman who was referred for genetic counseling due to a family history of Lynch syndrome caused by a MLH1 mutation. She originally underwent enucleation of the right eye secondary to a uveal spindle cell melanoma diagnosed at age 25. The tumor recurred 22 years later presenting as an ovarian metastasis and concurrently a microscopic endometrial endometrioid carcinoma, grade 1/3 was diagnosed. Subsequent studies highlighted that the uveal melanoma showed high microsatellite instability and loss of MLH1 and PMS2 protein expression, with no MLH1 promoter methylation or BRAF mutation. Additionally, a GNAQ mutation was found. We conclude that our patient's uveal melanoma is most likely related to MLH1 germline mutation and thus Lynch syndrome related. To the best of our knowledge, this is the first report of uveal melanoma showing MLH1/PMS2 protein loss in the context of Lynch syndrome.

  15. The MLH1 c.-27C>A and c.85G>T variants are linked to dominantly inherited MLH1 epimutation and are borne on a European ancestral haplotype.

    Science.gov (United States)

    Kwok, Chau-To; Vogelaar, Ingrid P; van Zelst-Stams, Wendy A; Mensenkamp, Arjen R; Ligtenberg, Marjolijn J; Rapkins, Robert W; Ward, Robyn L; Chun, Nicolette; Ford, James M; Ladabaum, Uri; McKinnon, Wendy C; Greenblatt, Marc S; Hitchins, Megan P

    2014-05-01

    Germline mutations of the DNA mismatch repair genes MLH1, MSH2, MSH6 or PMS2, and deletions affecting the EPCAM gene adjacent to MSH2, underlie Lynch syndrome by predisposing to early-onset colorectal, endometrial and other cancers. An alternative but rare cause of Lynch syndrome is constitutional epimutation of MLH1, whereby promoter methylation and transcriptional silencing of one allele occurs throughout normal tissues. A dominantly transmitted constitutional MLH1 epimutation has been linked to an MLH1 haplotype bearing two single-nucleotide variants, NM_000249.2: c.-27C>A and c.85G>T, in a Caucasian family with Lynch syndrome from Western Australia. Subsequently, a second seemingly unrelated Caucasian Australian case with the same MLH1 haplotype and concomitant epimutation was reported. We now describe three additional, ostensibly unrelated, cancer-affected families of European heritage with this MLH1 haplotype in association with constitutional epimutation, bringing the number of index cases reported to five. Array-based genotyping in four of these families revealed shared haplotypes between individual families that extended across ≤2.6-≤6.4 megabase regions of chromosome 3p, indicating common ancestry. A minimal ≤2.6 megabase founder haplotype common to all four families was identified, which encompassed MLH1 and additional flanking genes and segregated with the MLH1 epimutation in each family. Our findings indicate that the MLH1 c.-27C>A and c.85G>T variants are borne on a European ancestral haplotype and provide conclusive evidence for its pathogenicity via a mechanism of epigenetic silencing of MLH1 within normal tissues. Additional descendants bearing this founder haplotype may exist who are also at high risk of developing Lynch syndrome-related cancers.

  16. A tailored approach to BRAF and MLH1 methylation testing in a universal screening program for Lynch syndrome.

    Science.gov (United States)

    Adar, Tomer; Rodgers, Linda H; Shannon, Kristen M; Yoshida, Makoto; Ma, Tianle; Mattia, Anthony; Lauwers, Gregory Y; Iafrate, Anthony J; Chung, Daniel C

    2017-03-01

    To determine the correlation between BRAF genotype and MLH1 promoter methylation in a screening program for Lynch syndrome (LS), a universal screening program for LS was established in two medical centers. Tumors with abnormal MLH1 staining were evaluated for both BRAF V600E genotype and MLH1 promoter methylation. Tumors positive for both were considered sporadic, and genetic testing was recommended for all others. A total 1011 colorectal cancer cases were screened for Lynch syndrome, and 148 (14.6%) exhibited absent MLH1 immunostaining. Both BRAF and MLH1 methylation testing were completed in 126 cases. Concordant results (both positive or both negative) were obtained in 86 (68.3%) and 16 (12.7%) cases, respectively, with 81% concordance overall. The positive and negative predictive values for a BRAF mutation in predicting MLH1 promoter methylation were 98.9% and 41%, respectively, and the negative predictive value fell to 15% in patients ≥70 years old. Using BRAF genotyping as a sole test to evaluate cases with absent MLH1 staining would have increased referral rates for genetic testing by 2.3-fold compared with MLH1 methylation testing alone (31% vs 13.5%, respectively, PMLH1 methylation testing for BRAF wild-type cases only would significantly decrease the number of methylation assays performed and reduce the referral rate for genetic testing to 12.7%. A BRAF mutation has an excellent positive predictive value but poor negative predictive value in predicting MLH1 promoter methylation. A hybrid use of these tests may reduce the number of low-risk patients referred to genetic counseling and facilitate wider implementation of Lynch syndrome screening programs.

  17. Artefactual punctate MLH1 staining can lead to erroneous reporting of isolated PMS2 loss.

    Science.gov (United States)

    Niu, Bonnie T; Hammond, Rory F L; Leen, Sarah L S; Faruqi, Asma Z; Trevisan, Giorgia; Gilks, C Blake; Singh, Naveena

    2018-05-31

    Germline mutations in the PMS2 gene are an uncommon cause of Lynch Syndrome (LS), present in PMS2 immunohistochemical expression, with retained MLH1 expression, triggers referral to genetics services due to the significant risk of LS 3 . As detection of PMS2 germline mutations is problematic 4 , this may result in patients being labeled as "Lynch-like", with implications for future surveillance 5 . A recent study suggested that some cases of isolated PMS2 loss result from MLH1 promoter methylation and are sporadic rather than likely LS 6 ; they therefore recommended MLH1 promoter methylation testing in all cases of isolated PMS2 loss 6 . This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  18. MLH1 expression predicts the response to preoperative therapy and is associated with PD-L1 expression in esophageal cancer.

    Science.gov (United States)

    Momose, Kota; Yamasaki, Makoto; Tanaka, Koji; Miyazaki, Yasuhiro; Makino, Tomoki; Takahashi, Tsuyoshi; Kurokawa, Yukinori; Nakajima, Kiyokazu; Takiguchi, Shuji; Mori, Masaki; Doki, Yuichiro

    2017-07-01

    Programmed death-ligand 1 (PD-1/PD-L1) inhibition therapy demonstrates potential as a future treatment for esophageal cancer. Mismatch repair status and tumor PD-L1 expression are the candidate predictive biomarkers for response to this therapy. In colorectal cancer, mismatch repair-deficient tumors are associated with improved survival, although they are not sensitive to 5-fluorouracil-based chemotherapy. The purpose of the present study was to investigate the association between MutL homolog 1 (MLH1) expression and prognosis, response to therapy and PD-L1 expression in esophageal cancer. Immunohistochemistry was used to evaluate MLH1 and PD-L1 expression in 251 resected specimens. Of the specimens, 30.3% exhibited low MLH1 expression and 15.5% exhibited high PD-L1 expression. The 5-year overall survival rates for the high MLH1 expression group and the low MLH1 expression group were 51.3 and 55.6%, respectively (P=0.5260). The responder ratio was 45.7% in the high MLH1 expression group and 15.4% in the low MLH1 expression group (PMLH1 expression group (P=0.0064) and 25.0% in the low MLH1 expression group. MLH1 expression may be a predictive factor for the response to preoperative therapy in esophageal cancer, and esophageal cancer with low MLH1 expression may have a mechanism that assists in promoting tumor PD-L1 expression.

  19. Abrupt loss of MLH1 and PMS2 expression in endometrial carcinoma: molecular and morphologic analysis of 6 cases.

    Science.gov (United States)

    Pai, Rish K; Plesec, Thomas P; Abdul-Karim, Fadi W; Yang, Bin; Marquard, Jessica; Shadrach, Bonnie; Roma, Andres R

    2015-07-01

    Given that endometrial cancer (EC) is often the sentinel cancer for female Lynch syndrome patients, we have successfully implemented universal screening of ECs and have previously shown that this is the preferred method to identify these patients. However, during the course of universal screening of EC, we encountered 6 cases with an unusual pattern of mismatch-repair protein immunohistochemistry that has not been previously described in this setting. In these 6 cases, there was an abrupt loss of MLH1 and PMS2 expression in a portion of the tumor. In 3 cases, marked histologic differences were identified between the areas of the tumor with retained expression and areas with loss of expression. In 2 cases, the areas with loss of expression were of higher grade (1 demonstrated solid growth and the other demonstrated increased nuclear atypia with diffuse p53 expression). In 4 tumors, histologic features associated with microsatellite instability (MSI) were present, including increased intraepithelial lymphocytes. The areas with loss of and retained MLH1/PMS2 expression were separately microdissected and assessed for MSI and MLH1 promoter methylation. The areas with loss of MLH1 and PMS2 more commonly demonstrated MSI compared with the areas with intact expression (83% vs. 33%). MLH1 promoter methylation analysis demonstrated heterogenous hypermethylation, as all areas with loss of MLH1/PMS2 expression had more extensive methylation of MLH1 compared with those areas with retained expression. In summary, we describe the histologic and molecular features of 6 cases of EC with abrupt loss of MLH1 and PMS2 expression and demonstrate that heterogenous methylation of the MLH1 promoter results in this distinct and unusual pattern of immunohistochemical expression.

  20. MLH1 function is context dependent in colorectal cancers.

    Science.gov (United States)

    Jackson, Thomas; Ahmed, Mohamed A H; Seth, Rashmi; Jackson, Darryl; Ilyas, Mohammad

    2011-02-01

    Loss of mismatch repair (MMR) function in sporadic colorectal cancer occurs most commonly because of inactivation of MLH1, and it causes an increase in mutation rate. However, it is uncertain whether loss of MMR alters any other cellular function. The aim of this study was to investigate the role of MMR in regulating cell numbers and apoptosis. MLH1 protein levels were manipulated by (a) cloning and forcibly expressing MLH1 in HCT116 (a cell line with MLH1 mutation) and RKO (a cell line with MLH1 silencing), and (b) knockdown of MLH1 in SW480 (a cell line with normal MMR function). Cell number and apoptotic bodies were measured in standard and 'high stress' (ie, after staurosporine exposure) conditions. Restoration of MLH1 function in HCT116 and RKO resulted in increased cell number (pculture conditions. However, on induction of apoptotic stress, restoration of MLH1 resulted in reduced cell numbers (pcontext dependent: in 'low stress' conditions it may act to inhibit apoptosis, while in 'high stress' conditions it may induce apoptosis. However, within the context of chromosomal instability, the effect of MLH1 on cell numbers is limited.

  1. Expression of DNA mismatch repair proteins MLH1, MSH2, and MSH6 in recurrent glioblastoma.

    Science.gov (United States)

    Stark, Andreas M; Doukas, Alexander; Hugo, Heinz-Herrmann; Hedderich, Jürgen; Hattermann, Kirsten; Maximilian Mehdorn, H; Held-Feindt, Janka

    2015-02-01

    Methylated O6-methylguanin-DNA-methytransferase (MGMT) promoter methylation is associated with survival in patients with glioblastoma. Current evidence suggests that further mismatch repair genes play a pivotal role in the tumor response to treatment. Candidate genes are MLH1, MSH2, and MSH6. Formerly, we found evidence of prognostic impact of MLH1 and MSH6 immunohistochemical expression in a small series of patients with initial glioblastoma. Two hundred and eleven patients were included who underwent macroscopically total removal of primary glioblastoma and at least one re-craniotomy for recurrence. Immunohistochemical staining was performed on paraffin-embedded specimens of initial tumors with specific antibodies against MLH1, MSH2, and MSH6. RESULTS were compared to the Ki67 proliferation index and patient survival. Additionally, fresh frozen samples from 16 paired initial and recurrent specimens were examined using real-time reverse transcription polymerase chain reaction (RT-PCR) with specific primers against MLH1, MSH2, and MSH6. RESULTS were compared to MGMT status and survival. (1) Immunohistochemical expression of MSH6 was significantly associated with the Ki67 proliferation index (PMLH1, MLH2, and MSH6 over treatment combined with lacking MGMT methylation. In another two patients, decreased MLH1, MSH2, and MSH6 expression was observed in combination with MGMT promoter methylation. Our data indicate that there may be glioblastoma patient subgroups characterized by MMR-expression changes beyond MGMT promoter methylation. The immunohistochemical expression of MLH1, MSH2, and MSH6 in initial glioblastoma is not associated with patient survival.

  2. Promoting proximal formative assessment with relational discourse

    Science.gov (United States)

    Scherr, Rachel E.; Close, Hunter G.; McKagan, Sarah B.

    2012-02-01

    The practice of proximal formative assessment - the continual, responsive attention to students' developing understanding as it is expressed in real time - depends on students' sharing their ideas with instructors and on teachers' attending to them. Rogerian psychology presents an account of the conditions under which proximal formative assessment may be promoted or inhibited: (1) Normal classroom conditions, characterized by evaluation and attention to learning targets, may present threats to students' sense of their own competence and value, causing them to conceal their ideas and reducing the potential for proximal formative assessment. (2) In contrast, discourse patterns characterized by positive anticipation and attention to learner ideas increase the potential for proximal formative assessment and promote self-directed learning. We present an analysis methodology based on these principles and demonstrate its utility for understanding episodes of university physics instruction.

  3. Germline Hypermethylation of MLH1 and EPCAM Deletions Are a Frequent Cause of Lynch Syndrome

    NARCIS (Netherlands)

    Niessen, Renee C.; Hofstra, Robert M. W.; Westers, Helga; Ligtenberg, Marjolijn J. L.; Kooi, Krista; Jager, Paul O. J.; de Groote, Marloes L.; Dijkhuizen, Trijnie; Olderode-Berends, Maran J. W.; Hollema, Harry; Kleibeuker, Jan H.; Sijmons, Rolf H.

    It was shown that Lynch syndrome can be caused by germline hypermethylation of the MLH1 and MSH2 promoters. Furthermore, it has been demonstrated very recently that germline deletions of the 3' region of EPCAM cause transcriptional read-through which results in silencing of MSH2 by hypermethylation.

  4. Germline hypermethylation of MLH1 and EPCAM deletions are a frequent cause of Lynch syndrome.

    NARCIS (Netherlands)

    Niessen, R.C.; Hofstra, R.M.; Westers, H.; Ligtenberg, M.J.L.; Kooi, K.; Jager, P.O.; Groote, M.L. de; Dijkhuizen, T.; Olderode-Berends, M.J.; Hollema, H.; Kleibeuker, J.H.; Sijmons, R.H.

    2009-01-01

    It was shown that Lynch syndrome can be caused by germline hypermethylation of the MLH1 and MSH2 promoters. Furthermore, it has been demonstrated very recently that germline deletions of the 3' region of EPCAM cause transcriptional read-through which results in silencing of MSH2 by hypermethylation.

  5. Epigenetic silencing of the DNA mismatch repair gene, MLH1, induced by hypoxic stress in a pathway dependent on the histone demethylase, LSD1

    Science.gov (United States)

    Lu, Yuhong; Wajapeyee, Narendra; Turker, Mitchell S.; Glazer, Peter M.

    2014-01-01

    SUMMARY Silencing of the MLH1 gene is frequently seen in sporadic cancers. We report that hypoxia causes decreased H3K4 methylation at the MLH1 promoter via the H3K4 demethylases, LSD1 and PLU-1, and promotes long-term silencing of the promoter in a pathway that requires LSD1. Knockdown of LSD1 or its co-repressor, CoREST, also prevents the re-silencing (and cytosine DNA methylation) of the endogenous MLH1 promoter in RKO colon cancer cells following transient reactivation by the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine (5-aza-dC). The results demonstrate that hypoxia is a critical driving force for silencing of MLH1 through chromatin modification and indicate that the LSD1/CoREST complex is essential for MLH1 silencing. PMID:25043185

  6. Specific variants in the MLH1 gene region may drive DNA methylation, loss of protein expression, and MSI-H colorectal cancer.

    Directory of Open Access Journals (Sweden)

    Miralem Mrkonjic

    Full Text Available We previously identified an association between a mismatch repair gene, MLH1, promoter SNP (rs1800734 and microsatellite unstable (MSI-H colorectal cancers (CRCs in two samples. The current study expanded on this finding as we explored the genetic basis of DNA methylation in this region of chromosome 3. We hypothesized that specific polymorphisms in the MLH1 gene region predispose it to DNA methylation, resulting in the loss of MLH1 gene expression, mismatch-repair function, and consequently to genome-wide microsatellite instability.We first tested our hypothesis in one sample from Ontario (901 cases, 1,097 controls and replicated major findings in two additional samples from Newfoundland and Labrador (479 cases, 336 controls and from Seattle (591 cases, 629 controls. Logistic regression was used to test for association between SNPs in the region of MLH1 and CRC, MSI-H CRC, MLH1 gene expression in CRC, and DNA methylation in CRC. The association between rs1800734 and MSI-H CRCs, previously reported in Ontario and Newfoundland, was replicated in the Seattle sample. Two additional SNPs, in strong linkage disequilibrium with rs1800734, showed strong associations with MLH1 promoter methylation, loss of MLH1 protein, and MSI-H CRC in all three samples. The logistic regression model of MSI-H CRC that included MLH1-promoter-methylation status and MLH1 immunohistochemistry status fit most parsimoniously in all three samples combined. When rs1800734 was added to this model, its effect was not statistically significant (P-value  = 0.72 vs. 2.3×10(-4 when the SNP was examined alone.The observed association of rs1800734 with MSI-H CRC occurs through its effect on the MLH1 promoter methylation, MLH1 IHC deficiency, or both.

  7. Human MLH1 suppresses the insertion of telomeric sequences at intra-chromosomal sites in telomerase-expressing cells

    Science.gov (United States)

    Jia, Pingping; Chastain, Megan; Zou, Ying; Her, Chengtao

    2017-01-01

    Abstract Aberrant formation of interstitial telomeric sequences (ITSs) promotes genome instabilities. However, it is unclear how aberrant ITS formation is suppressed in human cells. Here, we report that MLH1, a key protein involved in mismatch repair (MMR), suppresses telomeric sequence insertion (TSI) at intra-chromosomal regions. The frequency of TSI can be elevated by double-strand break (DSB) inducer and abolished by ATM/ATR inhibition. Suppression of TSI requires MLH1 recruitment to DSBs, indicating that MLH1's role in DSB response/repair is important for suppressing TSI. Moreover, TSI requires telomerase activity but is independent of the functional status of p53 and Rb. Lastly, we show that TSI is associated with chromosome instabilities including chromosome loss, micronuclei formation and chromosome breakage that are further elevated by replication stress. Our studies uncover a novel link between MLH1, telomerase, telomere and genome stability. PMID:28180301

  8. Assessing pathogenicity of MLH1 variants by co-expression of human MLH1 and PMS2 genes in yeast

    Energy Technology Data Exchange (ETDEWEB)

    Vogelsang, Matjaz; Comino, Aleksandra; Zupanec, Neja [Department for Biosynthesis and Biotransformation, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana (Slovenia); Hudler, Petra [Medical Center for Molecular Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, SI-1000 Ljubljana (Slovenia); Komel, Radovan [Department for Biosynthesis and Biotransformation, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana (Slovenia); Medical Center for Molecular Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, SI-1000 Ljubljana (Slovenia)

    2009-10-28

    Loss of DNA mismatch repair (MMR) in humans, mainly due to mutations in the hMLH1 gene, is linked to hereditary nonpolyposis colorectal cancer (HNPCC). Because not all MLH1 alterations result in loss of MMR function, accurate characterization of variants and their classification in terms of their effect on MMR function is essential for reliable genetic testing and effective treatment. To date, in vivo assays for functional characterization of MLH1 mutations performed in various model systems have used episomal expression of the modified MMR genes. We describe here a novel approach to determine accurately the functional significance of hMLH1 mutations in vivo, based on co-expression of human MLH1 and PMS2 in yeast cells. Yeast MLH1 and PMS1 genes, whose protein products form the MutLα complex, were replaced by human orthologs directly on yeast chromosomes by homologous recombination, and the resulting MMR activity was tested. The yeast strain co-expressing hMLH1 and hPMS2 exhibited the same mutation rate as the wild-type. Eight cancer-related MLH1 variants were introduced, using the same approach, into the prepared yeast model, and their effect on MMR function was determined. Five variants (A92P, S93G, I219V, K618R and K618T) were classified as non-pathogenic, whereas variants T117M, Y646C and R659Q were characterized as pathogenic. Results of our in vivo yeast-based approach correlate well with clinical data in five out of seven hMLH1 variants and the described model was thus shown to be useful for functional characterization of MLH1 variants in cancer patients found throughout the entire coding region of the gene.

  9. Assessing pathogenicity of MLH1 variants by co-expression of human MLH1 and PMS2 genes in yeast

    Directory of Open Access Journals (Sweden)

    Hudler Petra

    2009-10-01

    Full Text Available Abstract Background Loss of DNA mismatch repair (MMR in humans, mainly due to mutations in the hMLH1 gene, is linked to hereditary nonpolyposis colorectal cancer (HNPCC. Because not all MLH1 alterations result in loss of MMR function, accurate characterization of variants and their classification in terms of their effect on MMR function is essential for reliable genetic testing and effective treatment. To date, in vivo assays for functional characterization of MLH1 mutations performed in various model systems have used episomal expression of the modified MMR genes. We describe here a novel approach to determine accurately the functional significance of hMLH1 mutations in vivo, based on co-expression of human MLH1 and PMS2 in yeast cells. Methods Yeast MLH1 and PMS1 genes, whose protein products form the MutLα complex, were replaced by human orthologs directly on yeast chromosomes by homologous recombination, and the resulting MMR activity was tested. Results The yeast strain co-expressing hMLH1 and hPMS2 exhibited the same mutation rate as the wild-type. Eight cancer-related MLH1 variants were introduced, using the same approach, into the prepared yeast model, and their effect on MMR function was determined. Five variants (A92P, S93G, I219V, K618R and K618T were classified as non-pathogenic, whereas variants T117M, Y646C and R659Q were characterized as pathogenic. Conclusion Results of our in vivo yeast-based approach correlate well with clinical data in five out of seven hMLH1 variants and the described model was thus shown to be useful for functional characterization of MLH1 variants in cancer patients found throughout the entire coding region of the gene.

  10. Assessing pathogenicity of MLH1 variants by co-expression of human MLH1 and PMS2 genes in yeast

    International Nuclear Information System (INIS)

    Vogelsang, Matjaz; Comino, Aleksandra; Zupanec, Neja; Hudler, Petra; Komel, Radovan

    2009-01-01

    Loss of DNA mismatch repair (MMR) in humans, mainly due to mutations in the hMLH1 gene, is linked to hereditary nonpolyposis colorectal cancer (HNPCC). Because not all MLH1 alterations result in loss of MMR function, accurate characterization of variants and their classification in terms of their effect on MMR function is essential for reliable genetic testing and effective treatment. To date, in vivo assays for functional characterization of MLH1 mutations performed in various model systems have used episomal expression of the modified MMR genes. We describe here a novel approach to determine accurately the functional significance of hMLH1 mutations in vivo, based on co-expression of human MLH1 and PMS2 in yeast cells. Yeast MLH1 and PMS1 genes, whose protein products form the MutLα complex, were replaced by human orthologs directly on yeast chromosomes by homologous recombination, and the resulting MMR activity was tested. The yeast strain co-expressing hMLH1 and hPMS2 exhibited the same mutation rate as the wild-type. Eight cancer-related MLH1 variants were introduced, using the same approach, into the prepared yeast model, and their effect on MMR function was determined. Five variants (A92P, S93G, I219V, K618R and K618T) were classified as non-pathogenic, whereas variants T117M, Y646C and R659Q were characterized as pathogenic. Results of our in vivo yeast-based approach correlate well with clinical data in five out of seven hMLH1 variants and the described model was thus shown to be useful for functional characterization of MLH1 variants in cancer patients found throughout the entire coding region of the gene

  11. Modulation of transcription factor binding and epigenetic regulation of the MLH1 CpG island and shore by polymorphism rs1800734 in colorectal cancer.

    Science.gov (United States)

    Savio, Andrea J; Bapat, Bharati

    2017-06-03

    The MLH1 promoter polymorphism rs1800734 is associated with MLH1 CpG island hypermethylation and expression loss in colorectal cancer (CRC). Conversely, variant rs1800734 is associated with MLH1 shore, but not island, hypomethylation in peripheral blood mononuclear cell DNA. To explore these distinct patterns, MLH1 CpG island and shore methylation was assessed in CRC cell lines stratified by rs1800734 genotype. Cell lines containing the variant A allele demonstrated MLH1 shore hypomethylation compared to wild type (GG). There was significant enrichment of transcription factor AP4 at the MLH1 promoter in GG and GA cell lines, but not the AA cell line, by chromatin immunoprecipitation studies. Preferential binding to the G allele was confirmed by sequencing in the GA cell line. The enhancer-associated histone modification H3K4me1 was enriched at the MLH1 shore; however, H3K27ac was not, indicating the shore is an inactive enhancer. These results demonstrate the role of variant rs1800734 in altering transcription factor binding as well as epigenetics at regions beyond the MLH1 CpG island in which it is located.

  12. Cancer risks for MLH1 and MSH2 mutation carriers

    OpenAIRE

    Dowty, James G.; Win, Aung K.; Buchanan, Daniel D.; Lindor, Noralane M.; Macrae, Finlay A.; Clendenning, Mark; Antill, Yoland C.; Thibodeau, Stephen N.; Casey, Graham; Gallinger, Steve; Le Marchand, Loic; Newcomb, Polly A.; Haile, Robert W.; Young, Graeme P.; James, Paul A.

    2013-01-01

    We studied 17,576 members of 166 MLH1 and 224 MSH2 mutation-carrying families from the Colon Cancer Family Registry. Average cumulative risks of colorectal cancer (CRC), endometrial cancer (EC) and other cancers for carriers were estimated using modified segregation analysis conditioned on ascertainment criteria. Heterogeneity in risks was investigated using a polygenic risk modifier. Average CRC cumulative risks to age 70 years (95% confidence intervals) for MLH1 and MSH2 mutation carriers, ...

  13. GLI1 interferes with the DNA mismatch repair system in pancreatic cancer through BHLHE41-mediated suppression of MLH1.

    Science.gov (United States)

    Inaguma, Shingo; Riku, Miho; Hashimoto, Mitsuyoshi; Murakami, Hideki; Saga, Shinsuke; Ikeda, Hiroshi; Kasai, Kenji

    2013-12-15

    The mismatch repair (MMR) system is indispensable for the fidelity of DNA replication, the impairment of which predisposes to the development and progression of many types of cancers. To date, GLI1 transcription factor, a key molecule of the Hedgehog signaling pathway, has been shown to regulate the expression of several genes crucial for a variety of cancer cell properties in many types of cancers, including pancreatic ductal adenocarcinoma (PDAC), but whether GLI1 could control the MMR system was not known. Here, we showed that GLI1 and GLI2 indirectly suppressed the expression of MLH1 in PDAC cells. Through GLI1 target gene screening, we found that GLI1 and GLI2 activated the expression of a basic helix-loop-helix type suppressor BHLHE41/DEC2/SHARP1 through a GLI-binding site in the promoter. Consistent with a previous report that BHLHE41 suppresses the MLH1 promoter activity, we found that the activation of GLI1 led to the BHLHE41-dependent suppression of MLH1, and a double knockdown of GLI1 and GLI2 conversely increased the MLH1 protein in PDAC cells. Using TALEN-based modification of the MLH1 gene, we further showed that GLI1 expression was indeed associated with an increased tolerance to a methylating agent, methylnitrosourea cooperatively with a lower copy number status of MLH1. Finally, GLI1 expression was immunohistochemically related positively with BHLHE41 and inversely with MLH1 in PDAC cells and precancerous lesions of the pancreas. On the basis of these results, we propose that GLI1 depresses the MMR activity and might contribute to the development and progression of PDAC. ©2013 AACR.

  14. Colorectal cancer incidence in path_MLH1 carriers subjected to different follow-up protocols

    DEFF Research Database (Denmark)

    Seppälä, Toni; Pylvänäinen, Kirsi; Evans, Dafydd Gareth

    2017-01-01

    We have previously reported a high incidence of colorectal cancer (CRC) in carriers of pathogenic MLH1 variants (path_MLH1) despite follow-up with colonoscopy including polypectomy.......We have previously reported a high incidence of colorectal cancer (CRC) in carriers of pathogenic MLH1 variants (path_MLH1) despite follow-up with colonoscopy including polypectomy....

  15. Clinical Significance of Epigenetic Inactivation of hMLH1 and BRCA1 in Tunisian Patients with Invasive Breast Carcinoma

    Directory of Open Access Journals (Sweden)

    Sondes Karray-Chouayekh

    2009-01-01

    Full Text Available Aberrant hypermethylation of gene promoter regions is one of the mechanisms for inactivation of tumour suppressor genes in many human cancers including breast carcinoma. In the current study, we aimed to assess by MSP, the methylation pattern of two cancer-related genes involved in DNA repair: hMLH1 (mutL homolog 1, colon cancer, nonpolyposis type 2 (E. coli and BRCA1 (breast cancer 1, early onset in 78 primary breast cancers from Tunisian patients. The methylation frequencies were 24.36% for hMLH1 and 46% for BRCA1. BRCA1 methylation correlated with age at diagnosis (P=.015 and 5-years disease free survival (P=.016 while hMLH1 methylation was more frequent in larger tumors (P=.002 and in presence of distant metastasis (P=.004. Furthermore, methylation of hMLH1 significantly correlated with high level of P53 expression (P=.006 and with overall survival (P=.015 suggesting that silencing of hMLH1 through aberrant promoter methylation could be used as a poor prognosis indicator in breast cancer.

  16. Promoter proximal polyadenylation sites reduce transcription activity

    DEFF Research Database (Denmark)

    Andersen, Pia Kjølhede; Lykke-Andersen, Søren; Jensen, Torben Heick

    2012-01-01

    Gene expression relies on the functional communication between mRNA processing and transcription. We previously described the negative impact of a point-mutated splice donor (SD) site on transcription. Here we demonstrate that this mutation activates an upstream cryptic polyadenylation (CpA) site......, which in turn causes reduced transcription. Functional depletion of U1 snRNP in the context of the wild-type SD triggers the same CpA event accompanied by decreased RNA levels. Thus, in accordance with recent findings, U1 snRNP can shield premature pA sites. The negative impact of unshielded pA sites...... on transcription requires promoter proximity, as demonstrated using artificial constructs and supported by a genome-wide data set. Importantly, transcription down-regulation can be recapitulated in a gene context devoid of splice sites by placing a functional bona fide pA site/transcription terminator within ∼500...

  17. Reduced migration of MLH1 deficient colon cancer cells depends on SPTAN1.

    Science.gov (United States)

    Hinrichsen, Inga; Ernst, Benjamin Philipp; Nuber, Franziska; Passmann, Sandra; Schäfer, Dieter; Steinke, Verena; Friedrichs, Nicolaus; Plotz, Guido; Zeuzem, Stefan; Brieger, Angela

    2014-01-24

    Defects in the DNA mismatch repair (MMR) protein MLH1 are frequently observed in sporadic and hereditary colorectal cancers (CRC). Affected tumors generate much less metastatic potential than the MLH1 proficient forms. Although MLH1 has been shown to be not only involved in postreplicative MMR but also in several MMR independent processes like cytoskeletal organization, the connection between MLH1 and metastasis remains unclear. We recently identified non-erythroid spectrin αII (SPTAN1), a scaffolding protein involved in cell adhesion and motility, to interact with MLH1. In the current study, the interaction of MLH1 and SPTAN1 and its potential consequences for CRC metastasis was evaluated. Nine cancer cell lines as well as fresh and paraffin embedded colon cancer tissue from 12 patients were used in gene expression studies of SPTAN1 and MLH1. Co-expression of SPTAN1 and MLH1 was analyzed by siRNA knock down of MLH1 in HeLa, HEK293, MLH1 positive HCT116, SW480 and LoVo cells. Effects on cellular motility were determined in MLH1 deficient HCT116 and MLH1 deficient HEK293T compared to their MLH1 proficient sister cells, respectively. MLH1 deficiency is clearly associated with SPTAN1 reduction. Moreover, siRNA knock down of MLH1 decreased the mRNA level of SPTAN1 in HeLa, HEK293 as well as in MLH1 positive HCT116 cells, which indicates a co-expression of SPTAN1 by MLH1. In addition, cellular motility of MLH1 deficient HCT116 and MLH1 deficient HEK293T cells was impaired compared to the MLH1 proficient sister clones. Consequently, overexpression of SPTAN1 increased migration of MLH1 deficient cells while knock down of SPTAN1 decreased cellular mobility of MLH1 proficient cells, indicating SPTAN1-dependent migration ability. These data suggest that SPTAN1 levels decreased in concordance with MLH1 reduction and impaired cellular mobility in MLH1 deficient colon cancer cells. Therefore, aggressiveness of MLH1-positive CRC might be related to SPTAN1.

  18. Association between MLH1 -93G>a polymorphism and risk of colorectal cancer.

    Directory of Open Access Journals (Sweden)

    Ting Wang

    Full Text Available The -93G>A (rs1800734 polymorphism located in the promoter of mismatch repair gene, MLH1, has been identified as a low-penetrance variant for cancer risk. Many published studies have evaluated the association between the MLH1 -93G>A polymorphism and colorectal cancer (CRC risk. However, the results remain conflicting rather than conclusive.The aim of this study was to assess the association between the MLH1 -93G>A polymorphism and the risk of CRC.To derive a more precise estimation of the association, a meta-analysis of six studies (17,791 cases and 13,782 controls was performed. Odds ratios (ORs and 95% confidence intervals (CIs were used to evaluate the strength of the association. Four of these published studies were performed on subjects of known microsatellite instability (MSI status. An additional analysis including 742 cases and 10,895 controls was used to assess the association between the MLH1 -93G>A polymorphism and the risk of MSI-CRC.The overall results indicated that the variant genotypes were associated with a significantly increased risk of CRC (AG versus GG: OR = 1.06, 95% CI = 1.01-1.11; AA/AG versus GG: OR = 1.06, 95% CI = 1.01-1.11. This increased risk was also found during stratified analysis of MSI status (AA versus GG: OR = 2.52, 95% CI = 1.94-3.28; AG versus GG: OR = 1.29, 95% CI = 1.10-1.52; AA/AG versus GG: OR = 1.45, 95% CI = 1.24-1.68; AA versusOR = 2.29, 95% CI = 1.78-2.96. Egger's test did not show any evidence of publication bias.Our results suggest that the MLH1 -93G>A polymorphism may contribute to individual susceptibility to CRC and act as a risk factor for MSI-CRC.

  19. Chronic exposure to arsenic, estrogen, and their combination causes increased growth and transformation in human prostate epithelial cells potentially by hypermethylation-mediated silencing of MLH1.

    Science.gov (United States)

    Treas, Justin; Tyagi, Tulika; Singh, Kamaleshwar P

    2013-11-01

    Chronic exposure to arsenic and estrogen is associated with risk of prostate cancer, but their mechanism is not fully understood. Additionally, the carcinogenic effects of their co-exposure are not known. Therefore, the objective of this study was to evaluate the effects of chronic exposure to arsenic, estrogen, and their combination, on cell growth and transformation, and identify the mechanism behind these effects. RWPE-1 human prostate epithelial cells were chronically exposed to arsenic and estrogen alone and in combination. Cell growth was measured by cell count and cell cycle, whereas cell transformation was evaluated by colony formation assay. Gene expression was measured by quantitative real-time PCR and confirmed at protein level by Western blot analysis. MLH1 promoter methylation was determined by pyrosequencing method. Exposure to arsenic, estrogen, and their combinations increases cell growth and transformation in RWPE-1 cells. Increased expression of Cyclin D1 and Bcl2, whereas decreased expression of mismatch repair genes MSH4, MSH6, and MLH1 was also observed. Hypermethylation of MLH1 promoter further suggested the epigenetic inactivation of MLH1 expression in arsenic and estrogen treated cells. Arsenic and estrogen combination caused greater changes than their individual treatments. Findings of this study for the first time suggest that arsenic and estrogen exposures cause increased cell growth and survival potentially through epigenetic inactivation of MLH1 resulting in decreased MLH1-mediated apoptotic response, and consequently increased cellular transformation. © 2013 Wiley Periodicals, Inc.

  20. Modulation of histone methylation and MLH1 gene silencing by hexavalent chromium

    International Nuclear Information System (INIS)

    Sun Hong; Zhou Xue; Chen Haobin; Li Qin; Costa, Max

    2009-01-01

    Hexavalent chromium [Cr(VI)] is a mutagen and carcinogen, and occupational exposure can lead to lung cancers and other adverse health effects. Genetic changes resulting from DNA damage have been proposed as an important mechanism that mediates chromate's carcinogenicity. Here we show that chromate exposure of human lung A549 cells increased global levels of di- and tri-methylated histone H3 lysine 9 (H3K9) and lysine 4 (H3K4) but decreased the levels of tri-methylated histone H3 lysine 27 (H3K27) and di-methylated histone H3 arginine 2 (H3R2). Most interestingly, H3K9 dimethylation was enriched in the human MLH1 gene promoter following chromate exposure and this was correlated with decreased MLH1 mRNA expression. Chromate exposure increased the protein as well as mRNA levels of G9a a histone methyltransferase that specifically methylates H3K9. This Cr(VI)-induced increase in G9a may account for the global elevation of H3K9 dimethylation. Furthermore, supplementation with ascorbate, the primary reductant of Cr(VI) and also an essential cofactor for the histone demethylase activity, partially reversed the H3K9 dimethylation induced by chromate. Thus our studies suggest that Cr(VI) may target histone methyltransferases and demethylases, which in turn affect both global and gene promoter specific histone methylation, leading to the silencing of specific tumor suppressor genes such as MLH1.

  1. DNA mismatch repair gene MLH1 induces apoptosis in prostate cancer cells.

    Science.gov (United States)

    Fukuhara, Shinichiro; Chang, Inik; Mitsui, Yozo; Chiyomaru, Takeshi; Yamamura, Soichiro; Majid, Shahana; Saini, Sharanjot; Hirata, Hiroshi; Deng, Guoren; Gill, Ankurpreet; Wong, Darryn K; Shiina, Hiroaki; Nonomura, Norio; Dahiya, Rajvir; Tanaka, Yuichiro

    2014-11-30

    Mismatch repair (MMR) enzymes have been shown to be deficient in prostate cancer (PCa). MMR can influence the regulation of tumor development in various cancers but their role on PCa has not been investigated. The aim of the present study was to determine the functional effects of the mutL-homolog 1 (MLH1) gene on growth of PCa cells. The DU145 cell line has been established as MLH1-deficient and thus, this cell line was utilized to determine effects of MLH1 by gene expression. Lack of MLH1 protein expression was confirmed by Western blotting in DU145 cells whereas levels were high in normal PWR-1E and RWPE-1 prostatic cells. MLH1-expressing stable transfectant DU145 cells were then created to characterize the effects this MMR gene has on various growth properties. Expression of MLH1 resulted in decreased cell proliferation, migration and invasion properties. Lack of cell growth in vivo also indicated a tumor suppressive effect by MLH1. Interestingly, MLH1 caused an increase in apoptosis along with phosphorylated c-Abl, and treatment with MLH1 siRNAs countered this effect. Furthermore, inhibition of c-Abl with STI571 also abrogated the effect on apoptosis caused by MLH1. These results demonstrate MLH1 protects against PCa development by inducing c-Abl-mediated apoptosis.

  2. The MLH1 ATPase domain is needed for suppressing aberrant formation of interstitial telomeric sequences.

    Science.gov (United States)

    Jia, Pingping; Chai, Weihang

    2018-05-01

    Genome instability gives rise to cancer. MLH1, commonly known for its important role in mismatch repair (MMR), DNA damage signaling and double-strand break (DSB) repair, safeguards genome stability. Recently we have reported a novel role of MLH1 in preventing aberrant formation of interstitial telomeric sequences (ITSs) at intra-chromosomal regions. Deficiency in MLH1, in particular its N-terminus, leads to an increase of ITSs. Here, we identify that the ATPase activity in the MLH1 N-terminal domain is important for suppressing the formation of ITSs. The ATPase activity is also needed for recruiting MLH1 to DSBs. Moreover, defective ATPase activity of MLH1 causes an increase in micronuclei formation. Our results highlight the crucial role of MLH1's ATPase domain in preventing the aberrant formation of telomeric sequences at the intra-chromosomal regions and preserving genome stability. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Differential cellular responses to prolonged LDR-IR in MLH1-proficient and MLH1-deficient colorectal cancer HCT116 cells.

    Science.gov (United States)

    Yan, Tao; Seo, Yuji; Kinsella, Timothy J

    2009-11-15

    MLH1 is a key DNA mismatch repair (MMR) protein involved in maintaining genomic stability by participating in the repair of endogenous and exogenous mispairs in the daughter strands during S phase. Exogenous mispairs can result following treatment with several classes of chemotherapeutic drugs, as well as with ionizing radiation. In this study, we investigated the role of the MLH1 protein in determining the cellular and molecular responses to prolonged low-dose rate ionizing radiation (LDR-IR), which is similar to the clinical use of cancer brachytherapy. An isogenic pair of MMR(+) (MLH1(+)) and MMR(-) (MLH1(-)) human colorectal cancer HCT116 cells was exposed to prolonged LDR-IR (1.3-17 cGy/h x 24-96 h). The clonogenic survival and gene mutation rates were examined. Cell cycle distribution was analyzed with flow cytometry. Changes in selected DNA damage repair proteins, DNA damage response proteins, and cell death marker proteins were examined with Western blotting. MLH1(+) HCT116 cells showed greater radiosensitivity with enhanced expression of apoptotic and autophagic markers, a reduced HPRT gene mutation rate, and more pronounced cell cycle alterations (increased late-S population and a G(2)/M arrest) following LDR-IR compared with MLH1(-) HCT116 cells. Importantly, a progressive increase in MLH1 protein levels was found in MLH1(+) cells during prolonged LDR-IR, which was temporally correlated with a progressive decrease in Rad51 protein (involved in homologous recombination) levels. MLH1 status significantly affects cellular responses to prolonged LDR-IR. MLH1 may enhance cell radiosensitivity to prolonged LDR-IR through inhibition of homologous recombination (through inhibition of Rad51).

  4. Loss of MLH1 sensitizes colon cancer cells to DNA-PKcs inhibitor KU60648.

    Science.gov (United States)

    Hinrichsen, Inga; Ackermann, Anne; Düding, Tonja; Graband, Annika; Filmann, Natalie; Plotz, Guido; Zeuzem, Stefan; Brieger, Angela

    2017-07-01

    Germline mutations of MLH1 are responsible for tumor generation in nearly 50% of patients with Lynch Syndrome, and around 15% of sporadic colorectal cancers show MLH1-deficiency due to promotor hypermethylation. Although these tumors are of lower aggressiveness the benefit for these patients from standard chemotherapy is still under discussion. Recently, it was shown that the sensitivity to the DNA-PKcs inhibitor KU60648 is linked to loss of the MMR protein MSH3. However, loss of MSH3 is rather secondary, as a consequence of MMR-deficiency, and frequently detectable in MLH1-deficient tumors. Therefore, we examined the expression of MLH1, MSH2, MSH6, and MSH3 in different MMR-deficient and proficient cell lines and determined their sensitivity to KU60648 by analyzing cell viability and survival. MLH1-dependent ability of double strand break (DSB) repair was monitored after irradiation via γH2AX detection. A panel of 12 colon cancer cell lines, two pairs of cells, where MLH1 knock down was compared to controls with the same genetic background, and one MLH1-deficient cell line where MLH1 was overexpressed, were included. In summary, we found that MLH1 and/or MSH3-deficient cells exhibited a significantly higher sensitivity to KU60648 than MMR-proficient cells and that overexpression of MLH1 in MLH1-deficient cells resulted in a decrease of cell sensitivity. KU60648 efficiency seems to be associated with reduced DSB repair capacity. Since the molecular testing of colon tumors for MLH1 expression is a clinical standard we believe that MLH1 is a much better marker and a greater number of patients would benefit from KU60648 treatment. © 2017 Wiley Periodicals, Inc.

  5. Tumor mismatch repair immunohistochemistry and DNA MLH1 methylation testing of patients with endometrial cancer diagnosed at age younger than 60 years optimizes triage for population-level germline mismatch repair gene mutation testing.

    Science.gov (United States)

    Buchanan, Daniel D; Tan, Yen Y; Walsh, Michael D; Clendenning, Mark; Metcalf, Alexander M; Ferguson, Kaltin; Arnold, Sven T; Thompson, Bryony A; Lose, Felicity A; Parsons, Michael T; Walters, Rhiannon J; Pearson, Sally-Ann; Cummings, Margaret; Oehler, Martin K; Blomfield, Penelope B; Quinn, Michael A; Kirk, Judy A; Stewart, Colin J; Obermair, Andreas; Young, Joanne P; Webb, Penelope M; Spurdle, Amanda B

    2014-01-10

    Clinicopathologic data from a population-based endometrial cancer cohort, unselected for age or family history, were analyzed to determine the optimal scheme for identification of patients with germline mismatch repair (MMR) gene mutations. Endometrial cancers from 702 patients recruited into the Australian National Endometrial Cancer Study (ANECS) were tested for MMR protein expression using immunohistochemistry (IHC) and for MLH1 gene promoter methylation in MLH1-deficient cases. MMR mutation testing was performed on germline DNA of patients with MMR-protein deficient tumors. Prediction of germline mutation status was compared for combinations of tumor characteristics, age at diagnosis, and various clinical criteria (Amsterdam, Bethesda, Society of Gynecologic Oncology, ANECS). Tumor MMR-protein deficiency was detected in 170 (24%) of 702 cases. Germline testing of 158 MMR-deficient cases identified 22 truncating mutations (3% of all cases) and four unclassified variants. Tumor MLH1 methylation was detected in 99 (89%) of 111 cases demonstrating MLH1/PMS2 IHC loss; all were germline MLH1 mutation negative. A combination of MMR IHC plus MLH1 methylation testing in women younger than 60 years of age at diagnosis provided the highest positive predictive value for the identification of mutation carriers at 46% versus ≤ 41% for any other criteria considered. Population-level identification of patients with MMR mutation-positive endometrial cancer is optimized by stepwise testing for tumor MMR IHC loss in patients younger than 60 years, tumor MLH1 methylation in individuals with MLH1 IHC loss, and germline mutations in patients exhibiting loss of MSH6, MSH2, or PMS2 or loss of MLH1/PMS2 with absence of MLH1 methylation.

  6. Clinical and prognosis value of the CIMP status combined with MLH1 or p16 INK4a methylation in colorectal cancer.

    Science.gov (United States)

    Saadallah-Kallel, Amana; Abdelmaksoud-Dammak, Rania; Triki, Mouna; Charfi, Slim; Khabir, Abdelmajid; Sallemi-Boudawara, Tahia; Mokdad-Gargouri, Raja

    2017-08-01

    Aberrant DNA methylation of CpG islands occurred frequently in CRC and associated with transcriptional silencing of key genes. In this study, the CIMP combined with MLH1 or p16 INK4a methylation status was determined in CRC patients and correlated with clinicopathological parameters and overall survival. Our data showed that CIMP+ CRCs were identified in 32.9% of cases and that CACNAG1 is the most frequently methylated promoter. When we combined the CIMP with the MLH1 or the p16 INK4a methylation status, we found that CIMP-/MLH1-U (37.8%) and CIMP-/p16 INK4a -U (35.4%) tumors were the most frequent among the four subtypes. Statistical analysis showed that tumor location, lymphovascular invasion, TNM stage, and MSI differed among the group of patients. Kaplan-Meier analyses revealed differences in overall survival according to the CIMP combined with MLH1 or p16 INK4a methylation status. In a multivariate analysis, CIMP/MLH1 and CIMP/p16 INK4a methylation statuses were predictive of prognosis, and the OS was longer for patients with tumors CIMP-/MLH1-M, as well as CIMP-/p16 INK4a -M. Furthermore, DNMT1 is significantly overexpressed in tumors than in normal tissues as well as in CIMP+ than CIMP- tumors. Our results suggest that tumor classification based on the CIMP status combined with MLH1 or p16 INK4a methylation is useful to predict prognosis in CRC patients.

  7. Correlation of MLH1 and MGMT methylation levels between peripheral blood leukocytes and colorectal tissue DNA samples in colorectal cancer patients.

    Science.gov (United States)

    Li, Xia; Wang, Yibaina; Zhang, Zuoming; Yao, Xiaoping; Ge, Jie; Zhao, Yashuang

    2013-11-01

    CpG island methylation in the promoter regions of the DNA mismatch repair gene mutator L homologue 1 ( MLH1 ) and DNA repair gene O 6 -methylguanine-DNA methyltransferase ( MGMT ) genes has been shown to occur in the leukocytes of peripheral blood and colorectal tissue. However, it is unclear whether the methylation levels in the blood leukocytes and colorectal tissue are correlated. The present study analyzed and compared the levels of MGMT and MLH1 gene methylation in the leukocytes of peripheral blood and colorectal tissues obtained from patients with colorectal cancer (CRC). The methylation levels of MGMT and MLH1 were examined using methylation-sensitive high-resolution melting (MS-HRM) analysis. A total of 44 patients with CRC were selected based on the MLH1 and MGMT gene methylation levels in the leukocytes of the peripheral blood. Corresponding colorectal tumor and normal tissues were obtained from each patient and the DNA methylation levels were determined. The correlation coefficients were evaluated using Spearman's rank test. Agreement was determined by generalized κ-statistics. Spearman's rank correlation coefficients (r) for the methylation levels of the MGMT and MLH1 genes in the leukocytes of the peripheral blood and normal colorectal tissue were 0.475 and 0.362, respectively (P=0.001 and 0.016, respectively). The agreement of the MGMT and MLH1 gene methylation levels in the leukocytes of the peripheral blood and normal colorectal tissue were graded as fair and poor (κ=0.299 and 0.126, respectively). The methylation levels of MGMT and MLH1 were moderately and weakly correlated between the patient-matched leukocytes and the normal colorectal tissue, respectively. Blood-derived DNA methylation measurements may not always represent the levels of normal colorectal tissue methylation.

  8. Effect of MLH1 -93G>A on gene expression in patients with colorectal cancer.

    Science.gov (United States)

    Funck, Alexandre; Santos, Juliana C; Silva-Fernandes, Isabelle J L; Rabenhorst, Silvia H B; Martinez, Carlos A R; Ribeiro, Marcelo L

    2014-09-01

    The DNA repair machinery plays a key role in maintaining genomic stability by preventing the emergence of mutations. Furthermore, the -93G>A polymorphism in the MLH1 gene has been associated with an increased risk of developing colorectal cancer. Therefore, the aim of this study was to examine the expression pattern and effect of this polymorphism in normal and tumour samples from patients with colorectal cancer. The MLH1 -93G>A (rs1800734) polymorphism was detected by PCR-RFLP in 49 cases of colorectal cancer. MLH1 expression was investigated using real-time quantitative PCR. The results indicate a significant decrease in MLH1 expression in tumour samples compared to their normal counterparts. The MLH1 gene was also significantly repressed in samples from patients who had some degree of tumour invasion into other organs. Similarly, those patients who were in a more advanced tumour stage (TNM III and IV) exhibited a significant reduction in MLH1 gene expression. Finally, the mutant genotype AA of MLH1 was associated with a significant decrease in the expression of this gene. This finding suggests that this polymorphism could increase the risk of developing colorectal cancer by a defective mismatch repair system, particularly through the loss of MLH1 expression in an allele-specific manner.

  9. Structure of the human MLH1 N-terminus: implications for predisposition to Lynch syndrome

    International Nuclear Information System (INIS)

    Wu, Hong; Zeng, Hong; Lam, Robert; Tempel, Wolfram; Kerr, Iain D.; Min, Jinrong

    2015-01-01

    The crystal structure of the human MLH1 N-terminus is reported at 2.30 Å resolution. The overall structure is described along with an analysis of two clinically important mutations. Mismatch repair prevents the accumulation of erroneous insertions/deletions and non-Watson–Crick base pairs in the genome. Pathogenic mutations in the MLH1 gene are associated with a predisposition to Lynch and Turcot’s syndromes. Although genetic testing for these mutations is available, robust classification of variants requires strong clinical and functional support. Here, the first structure of the N-terminus of human MLH1, determined by X-ray crystallography, is described. The structure shares a high degree of similarity with previously determined prokaryotic MLH1 homologs; however, this structure affords a more accurate platform for the classification of MLH1 variants

  10. Structure of the human MLH1 N-terminus: implications for predisposition to Lynch syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hong; Zeng, Hong; Lam, Robert; Tempel, Wolfram [University of Toronto, 101 College Street, Toronto, ON M5G 1L7 (Canada); Kerr, Iain D., E-mail: ikerr@myriad.com [Myriad Genetic Laboratories Inc., 320 Wakara Way, Salt Lake City, UT 84108 (United States); Min, Jinrong, E-mail: ikerr@myriad.com [University of Toronto, 101 College Street, Toronto, ON M5G 1L7 (Canada); University of Toronto, Toronto, ON M5G 1L7 (Canada)

    2015-07-28

    The crystal structure of the human MLH1 N-terminus is reported at 2.30 Å resolution. The overall structure is described along with an analysis of two clinically important mutations. Mismatch repair prevents the accumulation of erroneous insertions/deletions and non-Watson–Crick base pairs in the genome. Pathogenic mutations in the MLH1 gene are associated with a predisposition to Lynch and Turcot’s syndromes. Although genetic testing for these mutations is available, robust classification of variants requires strong clinical and functional support. Here, the first structure of the N-terminus of human MLH1, determined by X-ray crystallography, is described. The structure shares a high degree of similarity with previously determined prokaryotic MLH1 homologs; however, this structure affords a more accurate platform for the classification of MLH1 variants.

  11. Molecular analysis of MLH1 variants in Chinese sporadic colorectal cancer patients.

    Science.gov (United States)

    Peng, H X; Xu, X; Yang, R; Chu, Y M; Yang, D M; Xu, Y; Zhou, F L; Ma, W Z; Zhang, X J; Guan, M; Yang, Z H; Jin, Z D

    2016-04-26

    Single nucleotide polymorphisms (SNPs) in mismatch repair genes, especially in the MLH1 gene, are closely associated with susceptibility to hereditary nonpolyposis colorectal cancer. However, few relevant findings are available regarding the association between sporadic colorectal cancer (SCRC) and SNPs of MLH1 in Chinese patients. Therefore, the present study aimed to describe the pathogenic association between three important MLH1 polymorphisms and SCRC in the Chinese population. Peripheral blood samples from 156 SCRC patients and 311 healthy controls were collected. DNA was purified from peripheral blood, and the V384D, R217C, and I219V polymorphisms were evaluated using high-resolution melting analysis and direct sequencing. The association between the three important MLH1 polymorphisms and clinical pathological features of the SCRC patients was analyzed. In addition, PMS2-MLH1 protein interactions were determined by co-immunoprecipitation (Co-IP) to determine the protein functional alteration induced by these SNPs. Among the three polymorphisms, V384D was significantly associated with the risk of SCRC (OR = 31.36, P MLH1 R217C, V384D, and I219V variants had relative binding abilities with PMS2 of 0.59, 0.70, and 0.80, respectively, compared with the wild-type. These findings suggest that MLH1 V384D could be a promising genetic marker for susceptibility to SCRC.

  12. Expression of MLH1 and MSH2 in urothelial carcinoma of the renal pelvis.

    Science.gov (United States)

    Ehsani, Laleh; Osunkoya, Adeboye O

    2014-09-01

    In this study, we investigated microsatellite instability in urothelial carcinoma of the renal pelvis by lack of immunohistochemical staining for MLH1 and MSH2. The study included 44 cases of urothelial carcinoma of the renal pelvis obtained from radical nephroureterectomy specimens at our institution. We evaluated the loss of nuclear immunohistochemical staining of MLH1 and MSH2. Eight of 44 (18 %) patients had negative MLH1 expression and 25/44 (57 %) patients had negative MSH2 expression. Six of 8 (75 %) patients with negative MLH1 expression were male and 2/8 (25 %) patients were female. Nineteen of 25 (75 %) patients with negative MSH2 expression were male, and 6/25 (24 %) patients were female. Seven of 8 (88 %) cases with negative MLH1 expression were high-grade urothelial carcinoma, and 21/25 (84 %) cases with negative MSH2 expression were high-grade urothelial carcinoma. Twenty-one of 44 (48 %) cases had an inverted growth pattern, of which 3/21 (14 %) cases had negative MLH1 expression and 14/21 (67 %) cases had negative MSH2 expression. Our study showed that microsatellite instability based on negative expression of MLH1 and MSH2 was more common in male patients with high-grade urothelial carcinoma. There is a strong correlation between inverted growth pattern and negative MSH2 expression. Microsatellite instability testing should be performed in patients with upper urinary tract carcinoma and may have prognostic value.

  13. High Mutation Levels are Compatible with Normal Embryonic Development in Mlh1-Deficient Mice.

    Science.gov (United States)

    Fan, Xiaoyan; Li, Yan; Zhang, Yulong; Sang, Meixiang; Cai, Jianhui; Li, Qiaoxia; Ozaki, Toshinori; Ono, Tetsuya; He, Dongwei

    2016-10-01

    To elucidate the role of the mismatch repair gene Mlh1 in genome instability during the fetal stage, spontaneous mutations were studied in Mlh1-deficient lacZ-transgenic mouse fetuses. Mutation levels were high at 9.5 days post coitum (dpc) and gradually increased during the embryonic stage, after which they remained unchanged. In addition, mutations that were found in brain, liver, spleen, small intestine and thymus showed similar levels and no statistically significant difference was found. The molecular nature of mutations at 12.5 dpc in fetuses of Mlh1 +/+ and Mlh1 -/- mice showed their own unique spectra, suggesting that deletion mutations were the main causes in the deficiency of the Mlh1 gene. Of note, fetuses of irradiated mice exhibited marked differences such as post-implantation loss and Mendelian distribution. Collectively, these results strongly suggest that high mutation ofMlh1 -/- -deficient fetuses has little effect on the fetuses during their early developmental stages, whereas Mlh1 -/- -deficient fetuses from X-ray irradiated mothers are clearly effected.

  14. The dynamic DNA methylation landscape of the mutL homolog 1 shore is altered by MLH1-93G>A polymorphism in normal tissues and colorectal cancer.

    Science.gov (United States)

    Savio, Andrea J; Mrkonjic, Miralem; Lemire, Mathieu; Gallinger, Steven; Knight, Julia A; Bapat, Bharat

    2017-01-01

    Colorectal cancers (CRCs) undergo distinct genetic and epigenetic alterations. Expression of mutL homolog 1 ( MLH1 ), a mismatch repair gene that corrects DNA replication errors, is lost in up to 15% of sporadic tumours due to mutation or, more commonly, due to DNA methylation of its promoter CpG island. A single nucleotide polymorphism (SNP) in the CpG island of MLH1 ( MLH1 -93G>A or rs1800734) is associated with CpG island hypermethylation and decreased MLH1 expression in CRC tumours. Further, in peripheral blood mononuclear cell (PBMC) DNA of both CRC cases and non-cancer controls, the variant allele of rs1800734 is associated with hypomethylation at the MLH1 shore, a region upstream of its CpG island that is less dense in CpG sites . To determine whether this genotype-epigenotype association is present in other tissue types, including colorectal tumours, we assessed DNA methylation in matched normal colorectal tissue, tumour, and PBMC DNA from 349 population-based CRC cases recruited from the Ontario Familial Colorectal Cancer Registry. Using the semi-quantitative real-time PCR-based MethyLight assay, MLH1 shore methylation was significantly higher in tumour tissue than normal colon or PBMCs ( P  MLH1 was not associated with MSI status or promoter CpG island hypermethylation, regardless of genotype. To confirm these results, bisulfite sequencing was performed in matched tumour and normal colorectal specimens from six CRC cases, including two cases per genotype (wildtype, heterozygous, and homozygous variant). Bisulfite sequencing results corroborated the methylation patterns found by MethyLight, with significant hypomethylation in normal colorectal tissue of variant SNP allele carriers. These results indicate that the normal tissue types tested (colorectum and PBMC) experience dynamic genotype-associated epigenetic alterations at the MLH1 shore, whereas tumour DNA incurs aberrant hypermethylation compared to normal DNA.

  15. Activation of Saccharomyces cerevisiae Mlh1-Pms1 Endonuclease in a Reconstituted Mismatch Repair System*

    Science.gov (United States)

    Smith, Catherine E.; Bowen, Nikki; Graham, William J.; Goellner, Eva M.; Srivatsan, Anjana; Kolodner, Richard D.

    2015-01-01

    Previous studies reported the reconstitution of an Mlh1-Pms1-independent 5′ nick-directed mismatch repair (MMR) reaction using Saccharomyces cerevisiae proteins. Here we describe the reconstitution of a mispair-dependent Mlh1-Pms1 endonuclease activation reaction requiring Msh2-Msh6 (or Msh2-Msh3), proliferating cell nuclear antigen (PCNA), and replication factor C (RFC) and a reconstituted Mlh1-Pms1-dependent 3′ nick-directed MMR reaction requiring Msh2-Msh6 (or Msh2-Msh3), exonuclease 1 (Exo1), replication protein A (RPA), RFC, PCNA, and DNA polymerase δ. Both reactions required Mg2+ and Mn2+ for optimal activity. The MMR reaction also required two reaction stages in which the first stage required incubation of Mlh1-Pms1 with substrate DNA, with or without Msh2-Msh6 (or Msh2-Msh3), PCNA, and RFC but did not require nicking of the substrate, followed by a second stage in which other proteins were added. Analysis of different mutant proteins demonstrated that both reactions required a functional Mlh1-Pms1 endonuclease active site, as well as mispair recognition and Mlh1-Pms1 recruitment by Msh2-Msh6 but not sliding clamp formation. Mutant Mlh1-Pms1 and PCNA proteins that were defective for Exo1-independent but not Exo1-dependent MMR in vivo were partially defective in the Mlh1-Pms1 endonuclease and MMR reactions, suggesting that both reactions reflect the activation of Mlh1-Pms1 seen in Exo1-independent MMR in vivo. The availability of this reconstituted MMR reaction should now make it possible to better study both Exo1-independent and Exo1-dependent MMR. PMID:26170454

  16. Activation of Saccharomyces cerevisiae Mlh1-Pms1 Endonuclease in a Reconstituted Mismatch Repair System.

    Science.gov (United States)

    Smith, Catherine E; Bowen, Nikki; Graham, William J; Goellner, Eva M; Srivatsan, Anjana; Kolodner, Richard D

    2015-08-28

    Previous studies reported the reconstitution of an Mlh1-Pms1-independent 5' nick-directed mismatch repair (MMR) reaction using Saccharomyces cerevisiae proteins. Here we describe the reconstitution of a mispair-dependent Mlh1-Pms1 endonuclease activation reaction requiring Msh2-Msh6 (or Msh2-Msh3), proliferating cell nuclear antigen (PCNA), and replication factor C (RFC) and a reconstituted Mlh1-Pms1-dependent 3' nick-directed MMR reaction requiring Msh2-Msh6 (or Msh2-Msh3), exonuclease 1 (Exo1), replication protein A (RPA), RFC, PCNA, and DNA polymerase δ. Both reactions required Mg(2+) and Mn(2+) for optimal activity. The MMR reaction also required two reaction stages in which the first stage required incubation of Mlh1-Pms1 with substrate DNA, with or without Msh2-Msh6 (or Msh2-Msh3), PCNA, and RFC but did not require nicking of the substrate, followed by a second stage in which other proteins were added. Analysis of different mutant proteins demonstrated that both reactions required a functional Mlh1-Pms1 endonuclease active site, as well as mispair recognition and Mlh1-Pms1 recruitment by Msh2-Msh6 but not sliding clamp formation. Mutant Mlh1-Pms1 and PCNA proteins that were defective for Exo1-independent but not Exo1-dependent MMR in vivo were partially defective in the Mlh1-Pms1 endonuclease and MMR reactions, suggesting that both reactions reflect the activation of Mlh1-Pms1 seen in Exo1-independent MMR in vivo. The availability of this reconstituted MMR reaction should now make it possible to better study both Exo1-independent and Exo1-dependent MMR. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. De novo constitutional MLH1 epimutations confer early-onset colorectal cancer in two new sporadic Lynch syndrome cases, with derivation of the epimutation on the paternal allele in one.

    Science.gov (United States)

    Goel, Ajay; Nguyen, Thuy-Phuong; Leung, Hon-Chiu E; Nagasaka, Takeshi; Rhees, Jennifer; Hotchkiss, Erin; Arnold, Mildred; Banerji, Pia; Koi, Minoru; Kwok, Chau-To; Packham, Deborah; Lipton, Lara; Boland, C Richard; Ward, Robyn L; Hitchins, Megan P

    2011-02-15

    Lynch syndrome is an autosomal dominant cancer predisposition syndrome classically caused by germline mutations of the mismatch repair genes, MLH1, MSH2, MSH6 and PMS2. Constitutional epimutations of the MLH1 gene, characterized by soma-wide methylation of a single allele of the promoter and allelic transcriptional silencing, have been identified in a subset of Lynch syndrome cases lacking a sequence mutation in MLH1. We report two individuals with no family history of colorectal cancer who developed that disease at age 18 and 20 years. In both cases, cancer had arisen because of the de novo occurrence of a constitutional MLH1 epimutation and somatic loss-of-heterozygosity of the functional allele in the tumors. We show for the first time that the epimutation in one case arose on the paternally inherited allele. Analysis of 13 tumors from seven individuals with constitutional MLH1 epimutations showed eight tumors had lost the second MLH1 allele, two tumors had a novel pathogenic missense mutation and three had retained heterozygosity. Only 1 of 12 tumors demonstrated the BRAF V600E mutation and 3 of 11 tumors harbored a mutation in KRAS. The finding that epimutations can originate on the paternal allele provides important new insights into the mechanism of origin of epimutations. It is clear that the second hit in MLH1 epimutation-associated tumors typically has a genetic not epigenetic basis. Individuals with mismatch repair-deficient cancers without the BRAF V600E mutation are candidates for germline screening for sequence or methylation changes in MLH1. Copyright © 2010 UICC.

  18. Clinical Significance of MLH1 Methylation and CpG Island Methylator Phenotype as Prognostic Markers in Patients with Gastric Cancer

    Science.gov (United States)

    Shigeyasu, Kunitoshi; Nagasaka, Takeshi; Mori, Yoshiko; Yokomichi, Naosuke; Kawai, Takashi; Fuji, Tomokazu; Kimura, Keisuke; Umeda, Yuzo; Kagawa, Shunsuke; Goel, Ajay; Fujiwara, Toshiyoshi

    2015-01-01

    Background To improve the outcome of patients suffering from gastric cancer, a better understanding of underlying genetic and epigenetic events in this malignancy is required. Although CpG island methylator phenotype (CIMP) and microsatellite instability (MSI) have been shown to play pivotal roles in gastric cancer pathogenesis, the clinical significance of these events on survival outcomes in patients with gastric cancer remains unknown. Methods This study included a patient cohort with pathologically confirmed gastric cancer who had surgical resections. A cohort of 68 gastric cancers was analyzed. CIMP and MSI statuses were determined by analyzing promoter CpG island methylation status of 28 genes/loci, and genomic instability at 10 microsatellite markers, respectively. A Cox’s proportional hazards model was performed for multivariate analysis including age, stage, tumor differentiation, KRAS mutation status, and combined CIMP/MLH1 methylation status in relation to overall survival (OS). Results By multivariate analysis, longer OS was significantly correlated with lower pathologic stage (P = 0.0088), better tumor differentiation (P = 0.0267) and CIMP-high and MLH1 3' methylated status (P = 0.0312). Stratification of CIMP status with regards to MLH1 methylation status further enabled prediction of gastric cancer prognosis. Conclusions CIMP and/or MLH1 methylation status may have a potential to be prognostic biomarkers for patients with gastric cancer. PMID:26121593

  19. Clinical Significance of MLH1 Methylation and CpG Island Methylator Phenotype as Prognostic Markers in Patients with Gastric Cancer.

    Directory of Open Access Journals (Sweden)

    Kunitoshi Shigeyasu

    Full Text Available To improve the outcome of patients suffering from gastric cancer, a better understanding of underlying genetic and epigenetic events in this malignancy is required. Although CpG island methylator phenotype (CIMP and microsatellite instability (MSI have been shown to play pivotal roles in gastric cancer pathogenesis, the clinical significance of these events on survival outcomes in patients with gastric cancer remains unknown.This study included a patient cohort with pathologically confirmed gastric cancer who had surgical resections. A cohort of 68 gastric cancers was analyzed. CIMP and MSI statuses were determined by analyzing promoter CpG island methylation status of 28 genes/loci, and genomic instability at 10 microsatellite markers, respectively. A Cox's proportional hazards model was performed for multivariate analysis including age, stage, tumor differentiation, KRAS mutation status, and combined CIMP/MLH1 methylation status in relation to overall survival (OS.By multivariate analysis, longer OS was significantly correlated with lower pathologic stage (P = 0.0088, better tumor differentiation (P = 0.0267 and CIMP-high and MLH1 3' methylated status (P = 0.0312. Stratification of CIMP status with regards to MLH1 methylation status further enabled prediction of gastric cancer prognosis.CIMP and/or MLH1 methylation status may have a potential to be prognostic biomarkers for patients with gastric cancer.

  20. Cancer risks and immunohistochemical profiles linked to the Danish MLH1 Lynch syndrome founder mutation

    DEFF Research Database (Denmark)

    Therkildsen, Christina; Isinger-Ekstrand, Anna; Ladelund, Steen

    2012-01-01

    Founder mutations with a large impact in distinct populations have been described in Lynch syndrome. In Denmark, the MLH1 c.1667+2_1667_+8TAAATCAdelinsATTT mutation accounts for 25 % of the MLH1 mutant families. We used the national Danish hereditary nonpolyposis colorectal cancer register...... to estimate the cumulative lifetime risks for Lynch syndrome-associated cancer in 16 founder mutation families with comparison to 47 other MLH1 mutant families. The founder mutation conferred comparable risks for colorectal cancer (relative risks, RR, of 0.99 for males and 0.79 for females) and lower risks...... in 68 % with extensive inter-tumor variability despite the same underlying germline mutation. In conclusion, the Danish MLH1 founder mutation that accounts for a significant proportion of Lynch syndrome and is associated with a lower risk for extracolonic cancers....

  1. Sessile serrated adenomas with dysplasia: morphological patterns and correlations with MLH1 immunohistochemistry.

    Science.gov (United States)

    Liu, Cheng; Walker, Neal I; Leggett, Barbara A; Whitehall, Vicki Lj; Bettington, Mark L; Rosty, Christophe

    2017-12-01

    Sessile serrated adenomas are the precursor polyp of approximately 20% of colorectal carcinomas. Sessile serrated adenomas with dysplasia are rarely encountered and represent an intermediate step to malignant progression, frequently associated with loss of MLH1 expression. Accurate diagnosis of these lesions is important to facilitate appropriate surveillance, particularly because progression from dysplasia to carcinoma can be rapid. The current World Health Organization classification describes two main patterns of dysplasia occurring in sessile serrated adenomas, namely, serrated and conventional. However, this may not adequately reflect the spectrum of changes seen by pathologists in routine practice. Furthermore, subtle patterns of dysplasia that are nevertheless associated with loss of MLH1 expression are not encompassed in this classification. We performed a morphological analysis of 266 sessile serrated adenomas with dysplasia with concurrent MLH1 immunohistochemistry with the aims of better defining the spectrum of dysplasia occurring in these lesions and correlating dysplasia patterns with MLH1 expression. We found that dysplasia can be divided morphologically into four major patterns, comprising minimal deviation (19%), serrated (12%), adenomatous (8%) and not otherwise specified (79%) groups. Minimal deviation dysplasia is defined by minor architectural and cytological changes that typically requires loss of MLH1 immunohistochemical expression to support the diagnosis. Serrated dysplasia and adenomatous dysplasia have distinctive histological features and are less frequently associated with loss of MLH1 expression (13 and 5%, respectively). Finally, dysplasia not otherwise specified encompasses most cases and shows a diverse range of morphological changes that do not fall into the other subgroups and are frequently associated with loss of MLH1 expression (83%). This morphological classification of sessile serrated adenomas with dysplasia may represent an

  2. Autophagy influences the low-dose hyper-radiosensitivity of human lung adenocarcinoma cells by regulating MLH1.

    Science.gov (United States)

    Wang, Qiong; Xiao, Zhuya; Lin, Zhenyu; Zhou, Jie; Chen, Weihong; Jie, Wuyun; Cao, Xing; Yin, Zhongyuan; Cheng, Jing

    2017-06-01

    To investigate the impact of autophagy on the low-dose hyper-radiosensitivity (HRS) of human lung adenocarcinoma cells via MLH1 regulation. Immunofluorescent staining, Western blotting, and electron microscopy were utilized to detect autophagy in A549 and H460 cells. shRNA was used to silence MLH1 expression. The levels of MLH1, mTOR, p-mTOR, BNIP3, and Beclin-1 were measured by real-time polymerase chain reaction (PCR) and Western blotting. A549 cells, which have low levels of MLH1 expression, displayed HRS/induced radioresistance (IRR). Conversely, the radiosensitivity of H460 cells, which express high levels of MLH1, conformed to the linear-quadratic (LQ) model. After down-regulating MLH1 expression, A549 cells showed increased HRS and inhibition of autophagy, whereas H460 cells exhibited HRS/IRR. The levels of mTOR, p-mTOR, and BNIP3 were reduced in cells harboring MLH1 shRNA, and the changes in the mTOR/p-mTOR ratio mirrored those in MLH1 expression. Low MLH1-expressing A549 cells may exhibit HRS. Both the mTOR/p-mTOR and BNIP3/Beclin-1 signaling pathways were found to be related to HRS, but only mTOR/p-mTOR is involved in the regulation of HRS via MLH1 and autophagy.

  3. Differential expression of hMLH1 in sporadic human colorectal cancer tumors and distant metastases

    DEFF Research Database (Denmark)

    Larsen, Nicolai Balle; Heiberg Engel, Peter Johan; Rasmussen, Merete

    2009-01-01

    in expression between the tumor transition zone and the invasive front. Expression of hMSH2, hMLH1, and hPMS2 was screened immunohistochemically in 92 stage IV tumors and derived liver metastases. In cases with loss of mismatch repair protein expression, lymph node metastases were also examined....... Clinicopathological parameters and Ki-67 staining indexes were evaluated and compared. Four tumors displayed a complete loss of hMLH1/hPMS2 expression at the transition zone; however, three of these expressed both proteins at the invasive front and in liver and lymph node metastases. A further four were predominantly...... hMLH1/hPMS2 negative at the transition zone, but with distinct subclones of hMLH1/hPMS2-expressing cells at the transition zone. All of these tumors expressed hMLH1/hPMS2 at the invasive front and in liver metastases, with three also expressing hMLH/hPMS2 in lymph node metastases. No significant...

  4. Nuclear import of human MLH1, PMS2, and MutLalpha: redundancy is the key.

    Science.gov (United States)

    Leong, Vivian; Lorenowicz, Jessica; Kozij, Natalie; Guarné, Alba

    2009-08-01

    DNA mismatch repair maintains genomic stability by correcting errors that have escaped polymerase proofreading. Defects on mismatch repair genes lead to an increased mutation rate, microsatellite instability and predisposition to human non-polyposis colorectal cancer (HNPCC). Human MutLalpha is a heterodimer formed by the interaction of MLH1 and PMS2 that coordinates a series of key events in mismatch repair. It has been proposed that nuclear import of MutLalpha may be the first regulatory step on the activation of the mismatch repair pathway. Using confocal microscopy and mismatch repair deficient cells, we have identified the sequence determinants that drive nuclear import of human MLH1, PMS2, and MutLalpha. Transient transfection of the individual proteins reveals that MLH1 has a bipartite and PMS2 has a single monopartite nuclear localization signal. Although dimerization is not required for nuclear localization, the MutLalpha heterodimer is imported more efficiently than the MLH1 or PMS2 monomers. Interestingly, the bipartite localization signal of MLH1 can direct import of MutLalpha even when PMS2 encompasses a mutated localization signal. Hence we conclude that the presence of redundant nuclear localization signals guarantees nuclear transport of MutLalpha and, consequently, efficient mismatch repair.

  5. Ionizing radiation, inflammation, and their interactions in colon carcinogenesis in Mlh1-deficient mice.

    Science.gov (United States)

    Morioka, Takamitsu; Miyoshi-Imamura, Tomoko; Blyth, Benjamin J; Kaminishi, Mutsumi; Kokubo, Toshiaki; Nishimura, Mayumi; Kito, Seiji; Tokairin, Yutaka; Tani, Shusuke; Murakami-Murofushi, Kimiko; Yoshimi, Naoki; Shimada, Yoshiya; Kakinuma, Shizuko

    2015-03-01

    Genetic, physiological and environmental factors are implicated in colorectal carcinogenesis. Mutations in the mutL homolog 1 (MLH1) gene, one of the DNA mismatch repair genes, are a main cause of hereditary colon cancer syndromes such as Lynch syndrome. Long-term chronic inflammation is also a key risk factor, responsible for colitis-associated colorectal cancer; radiation exposure is also known to increase colorectal cancer risk. Here, we studied the effects of radiation exposure on inflammation-induced colon carcinogenesis in DNA mismatch repair-proficient and repair-deficient mice. Male and female Mlh1(-/-) and Mlh1(+/+) mice were irradiated with 2 Gy X-rays when aged 2 weeks or 7 weeks and/or were treated with 1% dextran sodium sulfate (DSS) in drinking water for 7 days at 10 weeks old to induce mild inflammatory colitis. No colon tumors developed after X-rays and/or DSS treatment in Mlh1(+/+) mice. Colon tumors developed after DSS treatment alone in Mlh1(-/-) mice, and exposure to radiation prior to DSS treatment increased the number of tumors. Histologically, colon tumors in the mice resembled the subtype of well-to-moderately differentiated adenocarcinomas with tumor-infiltrating lymphocytes of human Lynch syndrome. Immunohistochemistry revealed that expression of both p53 and β-catenin and loss of p21 and adenomatosis polyposis coli proteins were observed at the later stages of carcinogenesis, suggesting a course of molecular pathogenesis distinct from typical sporadic or colitis-associated colon cancer in humans. In conclusion, radiation exposure could further increase the risk of colorectal carcinogenesis induced by inflammation under the conditions of Mlh1 deficiency. © 2014 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

  6. Distinct effects of the recurrent Mlh1G67R mutation on MMR functions, cancer, and meiosis

    OpenAIRE

    Avdievich, Elena; Reiss, Cora; Scherer, Stefan J.; Zhang, Yongwei; Maier, Sandra M.; Jin, Bo; Hou, Harry; Rosenwald, Andreas; Riedmiller, Hubertus; Kucherlapati, Raju; Cohen, Paula E.; Edelmann, Winfried; Kneitz, Burkhard

    2008-01-01

    Mutations in the human DNA mismatch repair (MMR) gene MLH1 are associated with hereditary nonpolyposis colorectal cancer (Lynch syndrome, HNPCC) and a significant proportion of sporadic colorectal cancer. The inactivation of MLH1 results in the accumulation of somatic mutations in the genome of tumor cells and resistance to the genotoxic effects of a variety of DNA damaging agents. To study the effect of MLH1 missense mutations on cancer susceptibility, we generated a mouse line carrying the ...

  7. Functional characterization of MLH1 missense variants identified in Lynch Syndrome patients

    DEFF Research Database (Denmark)

    Andersen, Sofie Dabros; Liberti, Sascha Emilie; Lützen, Anne

    2012-01-01

    Germline mutations in the human DNA mismatch repair (MMR) genes MSH2 and MLH1 are associated with the inherited cancer disorder Lynch Syndrome (LS), also known as Hereditary Nonpolyposis Colorectal Cancer or HNPCC. A proportion of MSH2 and MLH1 mutations found in suspected LS patients give rise...... localization and protein-protein interaction with the dimer partner PMS2 and the MMR-associated exonuclease 1. We show that a significant proportion of examined variant proteins have functional defects in either subcellular localization or protein-protein interactions, which is suspected to lead to the cancer...

  8. Characterization of a Highly Conserved Binding Site of Mlh1 Required for Exonuclease I-Dependent Mismatch Repair

    DEFF Research Database (Denmark)

    Dherin, Claudine; Gueneau, Emeric; Francin, Mathilde

    2009-01-01

    Mlh1 is an essential factor of mismatch repair (MMR) and meiotic recombination. It interacts through its C-terminal region with MutL homologs and proteins involved in DNA repair and replication. In this study, we identified the site of yeast Mlh1 critical for the interaction with Exo1, Ntg2......, and Sgs1 proteins, designated as site S2 by reference to the Mlh1/Pms1 heterodimerization site S1. We show that site S2 is also involved in the interaction between human MLH1 and EXO1 or BLM. Binding at this site involves a common motif on Mlh1 partners that we called the MIP-box for the Mlh1 interacting...... protein box. Direct and specific interactions between yeast Mlh1 and peptides derived from Exo1, Ntg2, and Sgs1 and between human MLH1 and peptide derived from EXO1 and BLM were measured with K(d) values ranging from 8.1 to 17.4 microM. In Saccharomyces cerevisiae, a mutant of Mlh1 targeted at site S2...

  9. Association between hMLH1 hypermethylation and JC virus (JCV) infection in human colorectal cancer (CRC).

    Science.gov (United States)

    Vilkin, Alex; Niv, Yaron

    2011-04-01

    Incorporation of viral DNA may interfere with the normal sequence of human DNA bases on the genetic level or cause secondary epigenetic changes such as gene promoter methylation or histone acetylation. Colorectal cancer (CRC) is the second leading cause of cancer mortality in the USA. Chromosomal instability (CIN) was established as the key mechanism in cancer development. Later, it was found that CRC results not only from the progressive accumulation of genetic alterations but also from epigenetic changes. JC virus (JCV) is a candidate etiologic factor in sporadic CRC. It may act by stabilizing β-catenin, facilitating its entrance to the cell nucleus, initialing proliferation and cancer development. Diploid CRC cell lines transfected with JCV-containing plasmids developed CIN. This result provides direct experimental evidence for the ability of JCV T-Ag to induce CIN in the genome of colonic epithelial cells. The association of CRC hMLH1 methylation and tumor positivity for JCV was recently documented. JC virus T-Ag DNA sequences were found in 77% of CRCs and are associated with promoter methylation of multiple genes. hMLH1 was methylated in 25 out of 80 CRC patients positive for T-Ag (31%) in comparison with only one out of 11 T-Ag negative cases (9%). Thus, JCV can mediate both CIN and aberrant methylation in CRC. Like other viruses, chronic infection with JCV may induce CRC by different mechanisms which should be further investigated. Thus, gene promoter methylation induced by JCV may be an important process in CRC and the polyp-carcinoma sequence.

  10. Interdependence of DNA mismatch repair proteins MLH1 and MSH2 in apoptosis in human colorectal carcinoma cell lines.

    Science.gov (United States)

    Hassen, Samar; Ali, Akhtar A; Kilaparty, Surya P; Al-Anbaky, Qudes A; Majeed, Waqar; Boman, Bruce M; Fields, Jeremy Z; Ali, Nawab

    2016-01-01

    The mammalian DNA mismatch repair (MMR) system consists of a number of proteins that play important roles in repair of base pair mismatch mutations and in maintenance of genomic integrity. A defect in this system can cause genetic instability, which can lead to carcinogenesis. For instance, a germline mutation in one of the mismatch repair proteins, especially MLH1 or MSH2, is responsible for hereditary non-polyposis colorectal cancer. These MMR proteins also play an important role in the induction of apoptosis. Accordingly, altered expression of or a defect in MLH1 or MSH2 may confer resistance to anti-cancer drugs used in chemotherapy. We hypothesized that the ability of these two MMR proteins to regulate apoptosis are interdependent. Moreover, a defect in either one may confer resistance to chemotherapy by an inability to trigger apoptosis. To this end, we studied three cell lines-SW480, LoVo, and HTC116. These cell lines were selected based on their differential expression of MLH1 and MSH2 proteins. SW480 expresses both MLH1 and MSH2; LoVo expresses only MLH1 but not MSH2; HCT116 expresses only MSH2 but not MLH1 protein. MTT assays, a measure of cytotoxicity, showed that there were different cytotoxic effects of an anti-cancer drug, etoposide, on these cell lines, effects that were correlated with the MMR status of the cells. Cells that are deficient in MLH1 protein (HCT116 cells) were resistant to the drug. Cells that express both MLH1 and MSH2 proteins (SW480 cells) showed caspase-3 cleavage, an indicator of apoptosis. Cells that lack MLH1 (HCT116 cells) did not show any caspase-3 cleavage. Expression of full-length MLH1 protein was decreased in MMR proficient (SW480) cells during apoptosis; it remained unchanged in cells that lack MSH2 (LoVo cells). The expression of MSH2 protein remained unchanged during apoptosis both in MMR proficient (SW480) and deficient (HCT116) cells. Studies on translocation of MLH1 protein from nucleus to cytosolic fraction, an

  11. Utility of MLH1 methylation analysis in the clinical evaluation of Lynch Syndrome in women with endometrial cancer.

    Science.gov (United States)

    Bruegl, Amanda S; Djordjevic, Bojana; Urbauer, Diana L; Westin, Shannon N; Soliman, Pamela T; Lu, Karen H; Luthra, Rajyalakshmi; Broaddus, Russell R

    2014-01-01

    Clinical screening criteria, such as young age of endometrial cancer diagnosis and family history of signature cancers, have traditionally been used to identify women with Lynch Syndrome, which is caused by mutation of a DNA mismatch repair gene. Immunohistochemistry and microsatellite instability analysis have evolved as important screening tools to evaluate endometrial cancer patients for Lynch Syndrome. A complicating factor is that 15-20% of sporadic endometrial cancers have immunohistochemical loss of the DNA mismatch repair protein MLH1 and high levels of microsatellite instability due to methylation of MLH1. The PCR-based MLH1 methylation assay potentially resolves this issue, yet many clinical laboratories do not perform this assay. The objective of this study was to determine if clinical and pathologic features help to distinguish sporadic endometrial carcinomas with MLH1 loss secondary to MLH1 methylation from Lynch Syndrome-associated endometrial carcinomas with MLH1 loss and absence of MLH1 methylation. Of 337 endometrial carcinomas examined, 54 had immunohistochemical loss of MLH1. 40/54 had MLH1 methylation and were designated as sporadic, while 14/54 lacked MLH1 methylation and were designated as Lynch Syndrome. Diabetes and deep myometrial invasion were associated with Lynch Syndrome; no other clinical or pathological variable distinguished the 2 groups. Combining Society of Gynecologic Oncology screening criteria with these 2 features accurately captured all Lynch Syndrome cases, but with low specificity. In summary, no single clinical/pathologic feature or screening criteria tool accurately identified all Lynch Syndrome-associated endometrial carcinomas, highlighting the importance of the MLH1 methylation assay in the clinical evaluation of these patients.

  12. Evidence of constitutional MLH1 epimutation associated to transgenerational inheritance of cancer susceptibility.

    Science.gov (United States)

    Crépin, Michel; Dieu, Marie-Claire; Lejeune, Sophie; Escande, Fabienne; Boidin, Denis; Porchet, Nicole; Morin, Gilles; Manouvrier, Sylvie; Mathieu, Michèle; Buisine, Marie-Pierre

    2012-01-01

    Constitutional epimutations of DNA mismatch repair (MMR) genes have been recently reported as a possible cause of Lynch syndrome. However, little is known about their prevalence, the risk of transmission through the germline and the risk for carriers to develop cancers. In this study, we evaluated the contribution of constitutional epimutations of MMR genes in Lynch syndrome. A cohort of 134 unrelated Lynch syndrome-suspected patients without MMR germline mutation was screened for constitutional epimutations of MLH1 and MSH2 by quantitative bisulfite pyrosequencing. Patients were also screened for the presence of EPCAM deletions, a possible cause of MSH2 methylation. Tumors from patients with constitutional epimutations were extensively analyzed. We identified a constitutional MLH1 epimutation in two proband patients. For one of them, we report for the first time evidence of transmission to two children who also developed early colonic tumors, indicating that constitutional MLH1 epimutations are associated to a real risk of transgenerational inheritance of cancer susceptibility. Moreover, a somatic BRAF mutation was detected in one affected child, indicating that tumors from patients carrying constitutional MLH1 epimutation can mimic MSI-high sporadic tumors. These findings may have important implications for future diagnostic strategies and genetic counseling. © 2011 Wiley Periodicals, Inc.

  13. First report of a de novo germline mutation in the MLH1 gene

    NARCIS (Netherlands)

    Stulp, Rein P; Vos, Yvonne J; Mol, Bart; Karrenbeld, Arend; de Raad, Monique; van der Mijle, Huub J C; Sijmons, Rolf H

    2006-01-01

    Hereditary non-polyposis colorectal carcinoma (HNPCC) is an autosomal dominant disorder associated with colorectal and endometrial cancer and a range of other tumor types. Germline mutations in the DNA mismatch repair (MMR) genes, particularly MLH1, MSH2, and MSH6, underlie this disorder. The vast

  14. Expression defect size among unclassified MLH1 variants determines pathogenicity in Lynch syndrome diagnosis

    DEFF Research Database (Denmark)

    Hinrichsen, Inga; Brieger, Angela; Trojan, Jörg

    2013-01-01

    Lynch syndrome is caused by a germline mutation in a mismatch repair gene, most commonly the MLH1 gene. However, one third of the identified alterations are missense variants with unclear clinical significance. The functionality of these variants can be tested in the laboratory, but the results...

  15. Small suitability of the DLEC1, MLH1 and TUSC4 mRNA expression ...

    Indian Academy of Sciences (India)

    JACEK KORDIAK

    2017-06-18

    Jun 18, 2017 ... The DLEC1, TUSC4 and MLH1 expression was analysed in lung tumour tissue samples obtained from ... among men, however, the incidence is also rising in women ... rate of lung cancer patients is still poor, mainly because .... Up to 30 PYs. 18 ..... study performed by our group, high percentage (78%).

  16. Predictive value of CHFR and MLH1 methylation in human gastric cancer.

    Science.gov (United States)

    Li, Yazhuo; Yang, Yunsheng; Lu, Youyong; Herman, James G; Brock, Malcolm V; Zhao, Po; Guo, Mingzhou

    2015-04-01

    Gastric carcinoma (GC) has one of the highest mortality rates of cancer diseases and has a high incidence rate in China. Palliative chemotherapy is the main treatment for advanced gastric cancer. It is necessary to compare the effectiveness and toxicities of different regimens. This study explores the possibility of methylation of DNA damage repair genes serving as a prognostic and chemo-sensitive marker in human gastric cancer. The methylation status of five DNA damage repair genes (CHFR, FANCF, MGMT, MLH1, and RASSF1A) was detected by nested methylation-specific PCR in 102 paraffin-embedded gastric cancer samples. Chi-square or Fisher's exact tests were used to evaluate the association of methylation status and clinic-pathological factors. The Kaplan-Meier method and Cox proportional hazards models were employed to analyze the association of methylation status and chemo-sensitivity. The results indicate that CHFR, MLH1, RASSF1A, MGMT, and FANCF were methylated in 34.3% (35/102), 21.6% (22/102), 12.7% (13/102), 9.8% (10/102), and 0% (0/102) of samples, respectively. No association was found between methylation of CHFR, MLH1, RASSF1A, MGMT, or FANCF with gender, age, tumor size, tumor differentiation, lymph node metastasis, and TNM stage. In docetaxel-treated gastric cancer patients, resistance to docetaxel was found in CHFR unmethylated patients by Cox proportional hazards model (HR 0.243, 95% CI, 0.069-0.859, p = 0.028), and overall survival is longer in the CHFR methylated group compared with the CHFR unmethylated group (log-rank, p = 0.036). In oxaliplatin-treated gastric cancer patients, resistance to oxaliplatin was found in MLH1 methylated patients (HR 2.988, 95% CI, 1.064-8.394, p = 0.038), and overall survival was longer in the MLH1 unmethylated group compared with the MLH1 methylated group (log-rank, p = 0.046). CHFR is frequently methylated in human gastric cancer, and CHFR methylation may serve as a docetaxel-sensitive marker. MLH1 methylation was

  17. Immunohistochemical null-phenotype for mismatch repair proteins in colonic carcinoma associated with concurrent MLH1 hypermethylation and MSH2 somatic mutations.

    Science.gov (United States)

    Wang, Tao; Stadler, Zsofia K; Zhang, Liying; Weiser, Martin R; Basturk, Olca; Hechtman, Jaclyn F; Vakiani, Efsevia; Saltz, Lenard B; Klimstra, David S; Shia, Jinru

    2018-04-01

    Microsatellite instability, a well-established driver pathway in colorectal carcinogenesis, can develop in both sporadic and hereditary conditions via different molecular alterations in the DNA mismatch repair (MMR) genes. MMR protein immunohistochemistry (IHC) is currently widely used for the detection of MMR deficiency in solid tumors. The IHC test, however, can show varied staining patterns, posing challenges in the interpretation of the staining results in some cases. Here we report a case of an 80-year-old female with a colonic adenocarcinoma that exhibited an unusual "null" IHC staining pattern with complete loss of all four MMR proteins (MLH1, MSH2, MSH6, and PMS2). This led to subsequent MLH1 methylation testing and next generation sequencing which demonstrated that the loss of all MMR proteins was associated with concurrent promoter hypermethylation of MLH1 and double somatic truncating mutations in MSH2. These molecular findings, in conjunction with the patient's age being 80 years and the fact that the patient had no personal or family cancer history, indicated that the MMR deficiency was highly likely sporadic in nature. Thus, the stringent Lynch syndrome type surveillance programs were not recommended to the patient and her family members. This case illustrates a rare but important scenario where a null IHC phenotype signifies complex underlying molecular alternations that bear clinical management implications, highlighting the need for recognition and awareness of such unusual IHC staining patterns.

  18. MLH1-Silenced and Non-Silenced Subgroups of Hypermutated Colorectal Carcinomas Have Distinct Mutational Landscapes

    Science.gov (United States)

    Donehower, Lawrence A.; Creighton, Chad J.; Schultz, Nikolaus; Shinbrot, Eve; Chang, Kyle; Gunaratne, Preethi H.; Muzny, Donna; Sander, Chris; Hamilton, Stanley R.; Gibbs, Richard A.; Wheeler, David

    2014-01-01

    Approximately 15% of colorectal carcinomas (CRC) exhibit a hypermutated genotype accompanied by high levels of microsatellite instability (MSI-H) and defects in DNA mismatch repair. These tumors, unlike the majority of colorectal carcinomas, are often diploid, exhibit frequent epigenetic silencing of the MLH1 DNA mismatch repair gene, and have a better clinical prognosis. As an adjunct study to The Cancer Genome Atlas consortium that recently analyzed 224 colorectal cancers by whole exome sequencing, we compared the 35 CRC (15.6%) with a hypermutated genotype to those with a non-hypermutated genotype. We found that 22 (63%) of hypermutated CRC exhibited transcriptional silencing of the MLH1 gene, a high frequency of BRAF V600E gene mutations and infrequent APC and KRAS mutations, a mutational pattern significantly different from their non-hypermutated counterparts. However, the remaining 13 (37%) hypermutated CRC lacked MLH1 silencing, contained tumors with the highest mutation rates (“ultramutated” CRC), and exhibited higher incidences of APC and KRAS mutations, but infrequent BRAF mutations. These patterns were confirmed in an independent validation set of 250 exome-sequenced CRC. Analysis of mRNA and microRNA expression signatures revealed that hypermutated CRC with MLH1 silencing had greatly reduced levels of WNT signaling and increased BRAF signaling relative non-hypermutated CRC. Our findings suggest that hypermutated CRC include one subgroup with fundamentally different pathways to malignancy than the majority of CRC. Examination of MLH1 expression status and frequencies of APC, KRAS, and BRAF mutation in CRC may provide a useful diagnostic tool that could supplement the standard microsatellite instability assays and influence therapeutic decisions. PMID:22899370

  19. I219V polymorphism in hMLH1 gene in patients affected with ulcerative colitis.

    Science.gov (United States)

    Vietri, Maria Teresa; Riegler, Gabriele; De Paola, Marialaura; Simeone, Serena; Boggia, Maria; Improta, Alessia; Parisi, Mariarita; Molinari, Anna Maria; Cioffi, Michele

    2009-04-01

    hMLH1 gene, lying on chromosome 3p21-23, is a key factor of the mismatch repair (MMR) complex, which amends DNA replication errors. MMR alterations are involved in the development of both hereditary and sporadic forms of colorectal carcinoma related to ulcerative colitis (UC). I219V Polymorphism is located on exon 8 of hMLH1 and provides an aminoacidic substitution of isoleucine to valine, on the protein codon 219. This may affect the speed and fidelity of protein synthesis because of a tRNA paucity or changes in the mRNA secondary structure. Most of the hereditary nonpolyposis colon cancer-associated missense mutations of hMLH1 cause structural changes of the amino- or carboxy-terminal regions, involving the domains that interact with ATP and hPMS2. In this study, we analyzed the hMLH1 I219V polymorphism frequency in colectomized patients with UC. Venous blood from 100 ulcerative patients and 97 apparently healthy subjects has been collected. Out of 100 patients affected with UC, 75 noncolectomized showed an alternating course of disease, while 25 did not respond to the common drugs, and underwent colectomy. Genotyping was performed by polymerase chain reaction and following enzymatic digestion by BccI. No significant differences were found between patients with UC and controls both for genotype and allele frequencies. However, our data show a significant association when colectomized and noncolectomized patients are compared. The frequencies of G homozygosity were 28% in colectomized and 10.7% in noncolectomized patients (p < 0.05, chi(2) = 4.4, Odds ratio = 3.3). The allele frequencies of allele A were 52% in colectomized and 68% in noncolectomized patients; while those of allele G were 48% and 32%, respectively. I219V polymorphism in hMLH1 could influence the clinical course of the disease and lead to resistance to therapy.

  20. Completion of meiosis in male zebrafish (Danio rerio) despite lack of DNA mismatch repair gene mlh1.

    NARCIS (Netherlands)

    Leal, M.C.; Feitsma, H.; Cuppen, E.; Franca, L.R.; Schulz, R.W.

    2008-01-01

    Mlh1 is a member of DNA mismatch repair (MMR) machinery and is also essential for the stabilization of crossovers during the first meiotic division. Recently, we have shown that zebrafish mlh1 mutant males are completely infertile because of a block in metaphase I, whereas females are fertile but

  1. Functional implications of the p.Cys680Arg mutation in the MLH1 mismatch repair protein

    DEFF Research Database (Denmark)

    Dominguez-Valentin, Mev; Drost, Mark; Therkildsen, Christina

    2014-01-01

    >C missense mutation in exon 18 of the human MLH1 gene and biochemically characterization of the p.Cys680Arg mutant MLH1 protein to implicate it in the pathogenicity of the Lynch syndrome (LS). We show that the mutation is deficient in DNA mismatch repair and, therefore, contributing to LS in the carriers....

  2. Completion of meiosis in male zebrafish (Danio rerio) despite lack of DNA mismatch repair gene mlh1

    NARCIS (Netherlands)

    Leal, M.C.; Feitsma, H.; Cuppen, E.; França, L.R.; Schulz, R.W.

    2008-01-01

    Mlh1 is a member of DNA mismatch repair (MMR) machinery and is also essential for the stabilization of crossovers during the first meiotic division. Recently, we have shown that zebrafish mlh1 mutant males are completely infertile because of a block in metaphase I, whereas females are fertile

  3. Influence of MLH1 on colon cancer sensitivity to poly(ADP-ribose) polymerase inhibitor combined with irinotecan.

    Science.gov (United States)

    Tentori, Lucio; Leonetti, Carlo; Muzi, Alessia; Dorio, Annalisa Susanna; Porru, Manuela; Dolci, Susanna; Campolo, Federica; Vernole, Patrizia; Lacal, Pedro Miguel; Praz, Françoise; Graziani, Grazia

    2013-07-01

    Poly(ADP-ribose) polymerase inhibitors (PARPi) are currently evaluated in clinical trials in combination with topoisomerase I (Top1) inhibitors against a variety of cancers, including colon carcinoma. Since the mismatch repair component MLH1 is defective in 10-15% of colorectal cancers we have investigated whether MLH1 affects response to the Top1 inhibitor irinotecan, alone or in combination with PARPi. To this end, the colon cancer cell lines HCT116, carrying MLH1 mutations on chromosome 3 and HCT116 in which the wild-type MLH1 gene was replaced via chromosomal transfer (HCT116+3) or by transfection of the corresponding MLH1 cDNA (HCT116 1-2) were used. HCT116 cells or HCT116+3 cells stably silenced for PARP-1 expression were also analysed. The results of in vitro and in vivo experiments indicated that MLH1, together with low levels of Top1, contributed to colon cancer resistance to irinotecan. In the MLH1-proficient cells SN-38, the active metabolite of irinotecan, induced lower levels of DNA damage than in MLH1-deficient cells, as shown by the weaker induction of γ-H2AX and p53 phosphorylation. The presence of MLH1 contributed to induce of prompt Chk1 phosphorylation, restoring G2/M cell cycle checkpoint and repair of DNA damage. On the contrary, in the absence of MLH1, HCT116 cells showed minor Chk1 phosphorylation and underwent apoptosis. Remarkably, inhibition of PARP function by PARPi or by PARP-1 gene silencing always increased the antitumor activity of irinotecan, even in the presence of low PARP-1 expression.

  4. Functional examination of MLH1, MSH2, and MSH6 intronic mutations identified in Danish colorectal cancer patients.

    Science.gov (United States)

    Petersen, Sanne M; Dandanell, Mette; Rasmussen, Lene J; Gerdes, Anne-Marie; Krogh, Lotte N; Bernstein, Inge; Okkels, Henrik; Wikman, Friedrik; Nielsen, Finn C; Hansen, Thomas V O

    2013-10-03

    Germ-line mutations in the DNA mismatch repair genes MLH1, MSH2, and MSH6 predispose to the development of colorectal cancer (Lynch syndrome or hereditary nonpolyposis colorectal cancer). These mutations include disease-causing frame-shift, nonsense, and splicing mutations as well as large genomic rearrangements. However, a large number of mutations, including missense, silent, and intronic variants, are classified as variants of unknown clinical significance. Intronic MLH1, MSH2, or MSH6 variants were investigated using in silico prediction tools and mini-gene assay to asses the effect on splicing. We describe in silico and in vitro characterization of nine intronic MLH1, MSH2, or MSH6 mutations identified in Danish colorectal cancer patients, of which four mutations are novel. The analysis revealed aberrant splicing of five mutations (MLH1 c.588 + 5G > A, MLH1 c.677 + 3A > T, MLH1 c.1732-2A > T, MSH2 c.1276 + 1G > T, and MSH2 c.1662-2A > C), while four mutations had no effect on splicing compared to wild type (MLH1 c.117-34A > T, MLH1 c.1039-8 T > A, MSH2 c.2459-18delT, and MSH6 c.3439-16C > T). In conclusion, we classify five MLH1/MSH2 mutations as pathogenic, whereas four MLH1/MSH2/MSH6 mutations are classified as neutral. This study supports the notion that in silico prediction tools and mini-gene assays are important for the classification of intronic variants, and thereby crucial for the genetic counseling of patients and their family members.

  5. A modifier of Huntington's disease onset at the MLH1 locus.

    Science.gov (United States)

    Lee, Jong-Min; Chao, Michael J; Harold, Denise; Abu Elneel, Kawther; Gillis, Tammy; Holmans, Peter; Jones, Lesley; Orth, Michael; Myers, Richard H; Kwak, Seung; Wheeler, Vanessa C; MacDonald, Marcy E; Gusella, James F

    2017-10-01

    Huntington's disease (HD) is a dominantly inherited neurodegenerative disease caused by an expanded CAG repeat in HTT. Many clinical characteristics of HD such as age at motor onset are determined largely by the size of HTT CAG repeat. However, emerging evidence strongly supports a role for other genetic factors in modifying the disease pathogenesis driven by mutant huntingtin. A recent genome-wide association analysis to discover genetic modifiers of HD onset age provided initial evidence for modifier loci on chromosomes 8 and 15 and suggestive evidence for a locus on chromosome 3. Here, genotyping of candidate single nucleotide polymorphisms in a cohort of 3,314 additional HD subjects yields independent confirmation of the former two loci and moves the third to genome-wide significance at MLH1, a locus whose mouse orthologue modifies CAG length-dependent phenotypes in a Htt-knock-in mouse model of HD. Both quantitative and dichotomous association analyses implicate a functional variant on ∼32% of chromosomes with the beneficial modifier effect that delays HD motor onset by 0.7 years/allele. Genomic DNA capture and sequencing of a modifier haplotype localize the functional variation to a 78 kb region spanning the 3'end of MLH1 and the 5'end of the neighboring LRRFIP2, and marked by an isoleucine-valine missense variant in MLH1. Analysis of expression Quantitative Trait Loci (eQTLs) provides modest support for altered regulation of MLH1 and LRRFIP2, raising the possibility that the modifier affects regulation of both genes. Finally, polygenic modification score and heritability analyses suggest the existence of additional genetic modifiers, supporting expanded, comprehensive genetic analysis of larger HD datasets. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Single nucleotide polymorphisms in MLH1 predict poor prognosis of hepatocellular carcinoma in a Chinese population.

    Science.gov (United States)

    Zhu, Xiaonian; Liu, Wei; Qiu, Xiaoqiang; Wang, Zhigang; Tan, Chao; Bei, Chunhua; Qin, Linyuan; Ren, Yuan; Tan, Shengkui

    2017-10-03

    Hepatocellular carcinoma (HCC) is a malignant cancer causing deleterious health effect worldwide, especially in China. So far clinical cure rate and long-term survival rate of HCC remains low. Most HCC patients after cancer resection have recurrence or metastasis within 5 years. This study aims to explore the genetic association of mutL homolog 1 ( MLH1 ) polymorphisms with HCC risk and prognosis. Four candidate MLH1 polymorphisms, rs1800734, rs10849, rs3774343 and rs1540354 were studied from a hospital-based case-control study including 1,036 cases (HCC patients) and 1,036 controls (non-HCC patients) in Guangxi, China. All these SNPs interacted with environmental risk factors, such as HBV infection, alcohol intake and smoking in the pathogenesis of HCC. However, only rs1800734 had significant difference between cases and controls. Compared to the AA genotype, patients with AG, GG and AG/GG genotype of rs1800734 had an increased risk of HCC [ORs (95% CI) = 1.217 (1.074∼1.536), 1.745 (1.301∼2.591) and 1.291 (1.126∼1.687)] and a decreased survival time [co-dominant, HR (95% CI) = 1.553 (1.257∼1.920); dominant, HR (95% CI) = 2.207 (1.572∼3.100)]. Furthermore, we found that tumor number, tumor staging, metastasis and rs1800734 were associated with the overall survival of HCC patients by multivariate COX regression analysis. No significant difference was found between the other three MLH1 polymorphisms with HCC risk and prognosis. Our study suggests MLH1 SNP, rs1800734 as a new predictor for poor prognosis of HCC patients.

  7. Mlh1 deficiency in normal mouse colon mucosa associates with chromosomally unstable colon cancer

    Science.gov (United States)

    Pussila, Marjaana; Törönen, Petri; Einarsdottir, Elisabet; Katayama, Shintaro; Krjutškov, Kaarel; Holm, Liisa; Kere, Juha; Peltomäki, Päivi; Mäkinen, Markus J; Linden, Jere; Nyström, Minna

    2018-01-01

    Abstract Colorectal cancer (CRC) genome is unstable and different types of instabilities, such as chromosomal instability (CIN) and microsatellite instability (MSI) are thought to reflect distinct cancer initiating mechanisms. Although 85% of sporadic CRC reveal CIN, 15% reveal mismatch repair (MMR) malfunction and MSI, the hallmarks of Lynch syndrome with inherited heterozygous germline mutations in MMR genes. Our study was designed to comprehensively follow genome-wide expression changes and their implications during colon tumorigenesis. We conducted a long-term feeding experiment in the mouse to address expression changes arising in histologically normal colonic mucosa as putative cancer preceding events, and the effect of inherited predisposition (Mlh1+/−) and Western-style diet (WD) on those. During the 21-month experiment, carcinomas developed mainly in WD-fed mice and were evenly distributed between genotypes. Unexpectedly, the heterozygote (B6.129-Mlh1tm1Rak) mice did not show MSI in their CRCs. Instead, both wildtype and heterozygote CRC mice showed a distinct mRNA expression profile and shortage of several chromosomal segregation gene-specific transcripts (Mlh1, Bub1, Mis18a, Tpx2, Rad9a, Pms2, Cenpe, Ncapd3, Odf2 and Dclre1b) in their colon mucosa, as well as an increased mitotic activity and abundant numbers of unbalanced/atypical mitoses in tumours. Our genome-wide expression profiling experiment demonstrates that cancer preceding changes are already seen in histologically normal colon mucosa and that decreased expressions of Mlh1 and other chromosomal segregation genes may form a field-defect in mucosa, which trigger MMR-proficient, chromosomally unstable CRC. PMID:29701748

  8. The Germline MLH1 K618A Variant and Susceptibility to Lynch Syndrome-Associated Tumors

    Science.gov (United States)

    Medeiros, Fabiola; Lindor, Noralane M.; Couch, Fergus J.; Highsmith, W. Edward

    2013-01-01

    Missense variants discovered during sequencing of cancer susceptibility genes can be problematic for clinical interpretation. MLH1 K618A, which results from a 2-bp alteration (AAG→GCG) leading to a substitution of lysine to alanine in codon 618, has variously been interpreted as a pathogenic mutation, a variant of unknown significance, and a benign polymorphism. We evaluated the role of MLH1 K618A in predisposition to cancer by genotyping 1512 control subjects to assess its frequency in the general population. We also reviewed the literature concerning MLH1 K618A in families with colorectal cancer. The measured allele frequency of the K618A variant was 0.40%, which is remarkably close to the 0.44% summarized from 2491 control subjects in the literature. K618A was over-represented in families with suspected Lynch syndrome. In 1366 families, the allele frequency was 0.88% (OR = 2.1, 95% CI = 1.3 to 3.5; P = 0.006). In studies of sporadic cancers of the type associated with Lynch syndrome, K618A was over-represented in 1742 cases (allele frequency of 0.83) (OR = 2.0, 95% CI = 1.2 to 3.2; P = 0.008). We conclude that MLH1 K618A is not a fully penetrant Lynch syndrome mutation, although it is not without effect, appearing to increase the risk of Lynch syndrome-associated tumors approximately twofold. Our systematic assessment approach may be useful for variants in other genes. PMID:22426235

  9. Synchronous gastric and sebaceous cancers, a rare manifestation of MLH1-related Muir-Torre syndrome

    Czech Academy of Sciences Publication Activity Database

    Švec, Jiří; Schwarzová, L.; Janošíková, B.; Štekrová, J.; Mandys, V.; Kment, M.; Vodička, Pavel

    2014-01-01

    Roč. 7, č. 8 (2014), s. 5196-5202 ISSN 1936-2625 Grant - others:GA MŠk(CZ) Prvouk-P27/LF1/1; Univerzita Karlova(CZ) CZ.2.16/3.1.00/24024 Institutional support: RVO:68378041 Keywords : germline mutation * gastric cancer * MLH1 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.891, year: 2014

  10. Identification of Lynch syndrome mutations in the MLH1-PMS2 interface that disturb dimerization and mismatch repair.

    Science.gov (United States)

    Kosinski, Jan; Hinrichsen, Inga; Bujnicki, Janusz M; Friedhoff, Peter; Plotz, Guido

    2010-08-01

    Missense alterations of the mismatch repair gene MLH1 have been identified in a significant proportion of individuals suspected of having Lynch syndrome, a hereditary syndrome that predisposes for cancer of colon and endometrium. The pathogenicity of many of these alterations, however, is unclear. A number of MLH1 alterations are located in the C-terminal domain (CTD) of MLH1, which is responsible for constitutive dimerization with PMS2. We analyzed which alterations may result in pathogenic effects due to interference with dimerization. We used a structural model of CTD of MLH1-PMS2 heterodimer to select 19 MLH1 alterations located inside and outside two candidate dimerization interfaces in the MLH1-CTD. Three alterations (p.Gln542Leu, p.Leu749Pro, p.Tyr750X) caused decreased coexpression of PMS2, which is unstable in the absence of interaction with MLH1, suggesting that these alterations interfere with dimerization. All three alterations are located within the dimerization interface suggested by our model. They also compromised mismatch repair, suggesting that defects in dimerization abrogate repair and confirming that all three alterations are pathogenic. Additionally, we provided biochemical evidence that four alterations with uncertain pathogenicity (p.Ala586Pro, p.Leu636Pro, p.Thr662Pro, and p.Arg755Trp) are deleterious because of poor expression or poor repair efficiency, and confirm the deleterious effect of eight further alterations.

  11. Repair genes expression profile of MLH1, MSH2 and ATM in the normal oral mucosa of chronic smokers.

    Science.gov (United States)

    Alves, Mônica Ghislaine Oliveira; Carta, Celina Faig Lima; de Barros, Patrícia Pimentel; Issa, Jaqueline Scholz; Nunes, Fábio Daumas; Almeida, Janete Dias

    2017-01-01

    The aim of this study was to evaluate the effect of chronic smoking on the expression profile of the repair genes MLH1, MSH2 and ATM in the normal oral mucosa of chronic smokers and never smokers. The sample consisted of thirty exfoliative cytology smears per group obtained from Smokers and Never Smokers. Total RNA was extracted and expression of the MLH1, MSH2 and ATM genes were evaluated by quantitative real-time and immunocytochemistry. The gene and protein expression data were correlated to the clinical data. Gene expression was analyzed statistically using the Student t-test and Pearson's correlation coefficient, with pMLH1, MSH2 and ATM genes were downregulated in the smoking group compared to the control with significant values for MLH1 (p=0.006), MSH2 (p=0.0001) and ATM (p=0.0001). Immunocytochemical staining for anti-MLH1, anti-MSH2 and anti-ATM was negative in Never Smokers; in Smokers it was rarely positive. No significant correlation was observed among the expression of MLH1, MSH2, ATM and age, number of cigarettes consumed per day, time of smoking during life, smoking history or levels of CO in expired air. The expression of genes and proteins related to DNA repair mechanism MLH1, MSH2 and ATM in the normal oral mucosa of chronic smokers was reduced. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Novel Mutations in MLH1 and MSH2 Genes in Mexican Patients with Lynch Syndrome

    Directory of Open Access Journals (Sweden)

    Jose Miguel Moreno-Ortiz

    2016-01-01

    Full Text Available Background. Lynch Syndrome (LS is characterized by germline mutations in the DNA mismatch repair (MMR genes MLH1, MSH2, MSH6, and PMS2. This syndrome is inherited in an autosomal dominant pattern and is characterized by early onset colorectal cancer (CRC and extracolonic tumors. The aim of this study was to identify mutations in MMR genes in three Mexican patients with LS. Methods. Immunohistochemical analysis was performed as a prescreening method to identify absent protein expression. PCR, Denaturing High Performance Liquid Chromatography (dHPLC, and Sanger sequencing complemented the analysis. Results. Two samples showed the absence of nuclear staining for MLH1 and one sample showed loss of nuclear staining for MSH2. The mutations found in MLH1 gene were c.2103+1G>C in intron 18 and compound heterozygous mutants c.1852_1854delAAG (p.K618del and c.1852_1853delinsGC (p.K618A in exon 16. In the MSH2 gene, we identified mutation c.638dupT (p.L213fs in exon 3. Conclusions. This is the first report of mutations in MMR genes in Mexican patients with LS and these appear to be novel.

  13. A Mononucleotide Markers Panel to Identify hMLH1/hMSH2 Germline Mutations

    Directory of Open Access Journals (Sweden)

    M. Pedroni

    2007-01-01

    Full Text Available Hereditary NonPolyposis Colorectal Cancer (Lynch syndrome is an autosomal dominant disease caused by germline mutations in a class of genes deputed to maintain genomic integrity during cell replication, mutations result in a generalized genomic instability, particularly evident at microsatellite loci (Microsatellite Instability, MSI. MSI is present in 85–90% of colorectal cancers that occur in Lynch Syndrome. To standardize the molecular diagnosis of MSI, a panel of 5 microsatellite markers was proposed (known as the “Bethesda panel”. Aim of our study is to evaluate if MSI testing with two mononucleotide markers, such as BAT25 and BAT26, was sufficient to identify patients with hMLH1/hMSH2 germline mutations. We tested 105 tumours for MSI using both the Bethesda markers and the two mononucleotide markers BAT25 and BAT26. Moreover, immunohistochemical evaluation of MLH1 and MSH2 proteins was executed on the tumours with at least one unstable microsatellite, whereas germline hMLH1/hMSH2 mutations were searched for all cases showing two or more unstable microsatellites.

  14. Mutations in APC, CTNNB1 and K-ras genes and expression of hMLH1 in sporadic colorectal carcinomas from the Netherlands Cohort Study

    International Nuclear Information System (INIS)

    Lüchtenborg, Margreet; Weijenberg, Matty P; Wark, Petra A; Saritas, A Merdan; Roemen, Guido MJM; Muijen, Goos NP van; Bruïne, Adriaan P de; Brandt, Piet A van den; Goeij, Anton FPM de

    2005-01-01

    The early to intermediate stages of the majority of colorectal tumours are thought to be driven by aberrations in the Wnt (APC, CTNNB1) and Ras (K-ras) pathways. A smaller proportion of cancers shows mismatch repair deficiency. The aim of this study was to analyse the co-occurrence of these genetic alterations in relation to tumour and patient characteristics. In a group of 656 unselected sporadic colorectal cancer patients, aberrations in the APC, K-ras, CTNNB1 genes, and expression of hMLH1 were investigated. Additionally, tumours were divided in groups based on molecular features and compared with respect to patient's age at diagnosis, sex, family history of colorectal cancer, tumour sub-localisation, Dukes' stage and differentiation. Mutations at the phosphorylation sites (codons 31, 33, 37, and 45) in the CTNNB1 gene were observed in tumours from only 5/464 patients. Tumours with truncating APC mutations and activating K-ras mutations in codons 12 and 13 occurred at similar frequencies (37% (245/656) and 36% (235/656), respectively). Seventeen percent of tumours harboured both an APC and a K-ras mutation (109/656). Nine percent of all tumours (58/656) lacked hMLH1 expression. Patients harbouring a tumour with absent hMLH1 expression were older, more often women, more often had proximal colon tumours that showed poorer differentiation when compared to patients harbouring tumours with an APC and/or K-ras mutation. CTNNB1 mutations seem to be of minor importance in sporadic colorectal cancer. The main differences in tumour and patient characteristics are found between groups of patients based on mismatch repair deficiency

  15. Mutations in APC, CTNNB1 and K-ras genes and expression of hMLH1 in sporadic colorectal carcinomas from the Netherlands Cohort Study

    Directory of Open Access Journals (Sweden)

    de Bruïne Adriaan P

    2005-12-01

    Full Text Available Abstract Background The early to intermediate stages of the majority of colorectal tumours are thought to be driven by aberrations in the Wnt (APC, CTNNB1 and Ras (K-ras pathways. A smaller proportion of cancers shows mismatch repair deficiency. The aim of this study was to analyse the co-occurrence of these genetic alterations in relation to tumour and patient characteristics. Methods In a group of 656 unselected sporadic colorectal cancer patients, aberrations in the APC, K-ras, CTNNB1 genes, and expression of hMLH1 were investigated. Additionally, tumours were divided in groups based on molecular features and compared with respect to patient's age at diagnosis, sex, family history of colorectal cancer, tumour sub-localisation, Dukes' stage and differentiation. Results Mutations at the phosphorylation sites (codons 31, 33, 37, and 45 in the CTNNB1 gene were observed in tumours from only 5/464 patients. Tumours with truncating APC mutations and activating K-ras mutations in codons 12 and 13 occurred at similar frequencies (37% (245/656 and 36% (235/656, respectively. Seventeen percent of tumours harboured both an APC and a K-ras mutation (109/656. Nine percent of all tumours (58/656 lacked hMLH1 expression. Patients harbouring a tumour with absent hMLH1 expression were older, more often women, more often had proximal colon tumours that showed poorer differentiation when compared to patients harbouring tumours with an APC and/or K-ras mutation. Conclusion CTNNB1 mutations seem to be of minor importance in sporadic colorectal cancer. The main differences in tumour and patient characteristics are found between groups of patients based on mismatch repair deficiency.

  16. Functional characterization of rare missense mutations in MLH1 and MSH2 identified in Danish colorectal cancer patients

    DEFF Research Database (Denmark)

    Christensen, Lise Lotte; Kariola, Reetta; Korhonen, Mari K

    2009-01-01

    Recently, we have performed a population based study to analyse the frequency of colorectal cancer related MLH1 and MSH2 missense mutations in the Danish population. Half of the analyzed mutations were rare and most likely only present in the families where they were identified originally. Some...... of the missense mutations were located in conserved regions in the MLH1 and MSH2 proteins indicating a relation to disease development. In the present study, we functionally characterized 10 rare missense mutations in MLH1 and MSH2 identified in 13 Danish CRC families. To elucidate the pathogenicity...

  17. Immunohistochemical and DNA sequencing analysis on human mismatch repair gene MLH1 in cervical squamous cell carcinoma with LOH of this gene

    NARCIS (Netherlands)

    Hu, X.; Guo, Z.; Pang, T.; Li, Q.; Afink, G.; Pontén, J.

    2000-01-01

    BACKGROUND: The human MLH1 gene (hMLH1) is one of the DNA mismatch repair genes. Defects in these genes are believed to be the underlying cause of microsatellite instability (MSI). MSI has been demonstrated in many human cancers such as colon cancer and some female-specific tumors. The hMLH1 gene

  18. Tumors with unmethylated MLH1 and the CpG island methylator phenotype are associated with a poor prognosis in stage II colorectal cancer patients.

    Science.gov (United States)

    Fu, Tao; Liu, Yanliang; Li, Kai; Wan, Weiwei; Pappou, Emmanouil P; Iacobuzio-Donahue, Christine A; Kerner, Zachary; Baylin, Stephen B; Wolfgang, Christopher L; Ahuja, Nita

    2016-12-27

    We previously developed a novel tumor subtype classification model for duodenal adenocarcinomas based on a combination of the CpG island methylator phenotype (CIMP) and MLH1 methylation status. Here, we tested the prognostic value of this model in stage II colorectal cancer (CRC) patients. Tumors were assigned to CIMP+/MLH1-unmethylated (MLH1-U), CIMP+/MLH1-methylated (MLH1-M), CIMP-/MLH1-U, or CIMP-/MLH1-M groups. Age, tumor location, lymphovascular invasion, and mucin production differed among the four patient subgroups, and CIMP+/MLH1-U tumors were more likely to have lymphovascular invasion and mucin production. Kaplan-Meier analyses revealed differences in both disease-free survival (DFS) and overall survival (OS) among the four groups. In a multivariate analysis, CIMP/MLH1 methylation status was predictive of both DFS and OS, and DFS and OS were shortest in CIMP+/MLH1-U stage II CRC patients. These results suggest that tumor subtype classification based on the combination of CIMP and MLH1 methylation status is informative in stage II CRC patients, and that CIMP+/MLH1-U tumors exhibit aggressive features and are associated with poor clinical outcomes.

  19. Reduction of MLH1 and PMS2 confers temozolomide resistance and is associated with recurrence of glioblastoma.

    Science.gov (United States)

    Shinsato, Yoshinari; Furukawa, Tatsuhiko; Yunoue, Shunji; Yonezawa, Hajime; Minami, Kentarou; Nishizawa, Yukihiko; Ikeda, Ryuji; Kawahara, Kohichi; Yamamoto, Masatatsu; Hirano, Hirofumi; Tokimura, Hiroshi; Arita, Kazunori

    2013-12-01

    Although there is a relationship between DNA repair deficiency and temozolomide (TMZ) resistance in glioblastoma (GBM), it remains unclear which molecule is associated with GBM recurrence. We isolated three TMZ-resistant human GBM cell lines and examined the expression of O6-methylguanine-DNA methyltransferase (MGMT) and mismatch repair (MMR) components. We used immunohistochemical analysis to compare MutL homolog 1 (MLH1), postmeiotic segregation increased 2 (PMS2) and MGMT expression in primary and recurrent GBM specimens obtained from GBM patients during TMZ treatment. We found a reduction in MLH1 expression and a subsequent reduction in PMS2 protein levels in TMZ-resistant cells. Furthermore, MLH1 or PMS2 knockdown confered TMZ resistance. In recurrent GBM tumours, the expression of MLH1 and PMS2 was reduced when compared to primary tumours.

  20. Screening for germline mutations of MLH1, MSH2, MSH6 and PMS2 genes in Slovenian colorectal cancer patients: implications for a population specific detection strategy of Lynch syndrome.

    Science.gov (United States)

    Berginc, Gasper; Bracko, Matej; Ravnik-Glavac, Metka; Glavac, Damjan

    2009-01-01

    Microsatellite instability (MSI) is present in more than 90% of colorectal cancers of patients with Lynch syndrome, and is therefore a feasible marker for the disease. Mutations in MLH1, MSH2, MSH6 and PMS2, which are one of the main causes of deficient mismatch repair and subsequent MSI, have been linked to the disease. In order to establish the role of each of the 4 genes in Slovenian Lynch syndrome patients, we performed MSI analysis on 593 unselected CRC patients and subsequently searched for the presence of point mutations, larger genomic rearrangements and MLH1 promoter hypermethylation in patients with MSI-high tumours. We detected 43 (7.3%) patients with MSI-H tumours, of which 7 patients (1.3%) harboured germline defects: 2 in MLH1, 4 in MSH2, 1 in PMS2 and none in MSH6. Twenty-nine germline sequence variations of unknown significance and 17 deleterious somatic mutations were found. MLH1 promoter methylation was detected in 56% of patients without detected germline defects and in 1 (14%) suspected Lynch syndrome. Due to the minor role of germline MSH6 mutations, we adapted the Lynch syndrome detection strategy for the Slovenian population of CRC patients, whereby germline alterations should be first sought in MLH1 and MSH2 followed by a search for larger genomic rearrangements in these two genes. When no germline mutations are found tumors should be further tested for the presence of germline defects in PMS2 and MSH6. The choice about which gene should be tested first can be guided more accurately by the immunohistochemical analysis. Our study demonstrates that the incidence of MMR mutations in a population should be known prior to the application of one of several suggested strategies for detection of Lynch syndrome.

  1. The unstructured linker arms of Mlh1-Pms1 are important for interactions with DNA during mismatch repair

    Science.gov (United States)

    Plys, Aaron J.; Rogacheva, Maria V.; Greene, Eric C.; Alani, Eric

    2012-01-01

    DNA mismatch repair (MMR) models have proposed that MSH proteins identify DNA polymerase errors while interacting with the DNA replication fork. MLH proteins (primarily Mlh1-Pms1 in baker’s yeast) then survey the genome for lesion-bound MSH proteins. The resulting MSH-MLH complex formed at a DNA lesion initiates downstream steps in repair. MLH proteins act as dimers and contain long (20 – 30 nanometers) unstructured arms that connect two terminal globular domains. These arms can vary between 100 to 300 amino acids in length, are highly divergent between organisms, and are resistant to amino acid substitutions. To test the roles of the linker arms in MMR, we engineered a protease cleavage site into the Mlh1 linker arm domain of baker’s yeast Mlh1-Pms1. Cleavage of the Mlh1 linker arm in vitro resulted in a defect in Mlh1-Pms1 DNA binding activity, and in vivo proteolytic cleavage resulted in a complete defect in MMR. We then generated a series of truncation mutants bearing Mlh1 and Pms1 linker arms of varying lengths. This work revealed that MMR is greatly compromised when portions of the Mlh1 linker are removed, whereas repair is less sensitive to truncation of the Pms1 linker arm. Purified complexes containing truncations in Mlh1 and Pms1 linker arms were analyzed and found to have differential defects in DNA binding that also correlated with the ability to form a ternary complex with Msh2-Msh6 and mismatch DNA. These observations are consistent with the unstructured linker domains of MLH proteins providing distinct interactions with DNA during MMR. PMID:22659005

  2. Prevalence of MLH1 constitutional epimutations as a cause of Lynch syndrome in unselected versus selected consecutive series of patients with colorectal cancer.

    Science.gov (United States)

    Castillejo, Adela; Hernández-Illán, Eva; Rodriguez-Soler, María; Pérez-Carbonell, Lucía; Egoavil, Cecilia; Barberá, Victor M; Castillejo, María-Isabel; Guarinos, Carla; Martínez-de-Dueñas, Eduardo; Juan, María-Jose; Sánchez-Heras, Ana-Beatriz; García-Casado, Zaida; Ruiz-Ponte, Clara; Brea-Fernández, Alejandro; Juárez, Miriam; Bujanda, Luis; Clofent, Juan; Llor, Xavier; Andreu, Montserrat; Castells, Antoni; Carracedo, Angel; Alenda, Cristina; Payá, Artemio; Jover, Rodrigo; Soto, José-Luis

    2015-07-01

    The prevalence of MLH1 constitutional epimutations in the general population is unknown. We sought to analyse the prevalence of MLH1 constitutional epimutations in unselected and selected series of patients with colorectal cancer (CRC). Patients with diagnoses of CRC (n=2123) were included in the unselected group. For comparison, a group of 847 selected patients with CRC who fulfilled the revised Bethesda guidelines (rBG) were also included. Somatic and constitutional MLH1 methylation was assayed via methylation-specific multiplex ligation-dependent probe amplification of cases lacking MLH1 expression. Germline alterations in mismatch-repair (MMR) genes were assessed via Sanger sequencing and methylation-specific multiplex ligation-dependent probe amplification. Loss of MLH1 expression occurred in 5.5% of the unselected series and 12.5% of the selected series (pMLH1 were detected in the unselected population (0/62); five cases from the selected series were positive for MLH1 epimutations (15.6%, 5/32; p=0.004). Our results suggest a negligible prevalence of MLH1 constitutional epimutations in unselected cases of CRC. Therefore, MLH1 constitutional epimutation analysis should be conducted only for patients who fulfil the rBG and who lack MLH1 expression with methylated MLH1. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  3. Subsets of microsatellite-unstable colorectal cancers exhibit discordance between the CpG island methylator phenotype and MLH1 methylation status.

    Science.gov (United States)

    Kim, Jung H; Rhee, Ye-Y; Bae, Jeong-M; Kwon, Hyeong-J; Cho, Nam-Y; Kim, Mi J; Kang, Gyeong H

    2013-07-01

    Although the presence of MLH1 methylation in microsatellite-unstable colorectal cancer generally indicates involvement of the CpG island methylator phenotype (CIMP) in the development of the tumor, these two conditions do not always correlate. A minority of microsatellite-unstable colorectal cancers exhibit discordance between CIMP and MLH1 methylation statuses. However, the clinicopathological features of such microsatellite-unstable colorectal cancers with discrepant MLH1 methylation and CIMP statuses remain poorly studied. Microsatellite-unstable colorectal cancers (n=220) were analyzed for CIMP and MLH1 methylation statuses using the MethyLight assay. Based on the combinatorial CIMP and MLH1 methylation statuses, the microsatellite-unstable colorectal cancers were grouped into four subtypes (CIMP-high (CIMP-H) MLH1 methylation-positive (MLH1m+), CIMP-H MLH1 methylation-negative, CIMP-low/0 (CIMP-L/0) MLH1m+, and CIMP-L/0 MLH1 methylation-negative), which were compared in terms of their associations with clinicopathological and molecular features. The CIMP-L/0 MLH1 methylation-negative and CIMP-H MLH1m+ subtypes were predominant, comprising 63.6 and 24.1% of total microsatellite-unstable colorectal cancers, respectively. The discordant subtypes, CIMP-H MLH1 methylation-negative and CIMP-L/0 MLH1m+, were found in 5 and 7% of microsatellite-unstable colorectal cancers, respectively. The CIMP-H MLH1 methylation-negative subtype exhibited elevated incidence rates in male patients and was associated with larger tumor size, more frequent loss of MSH2 expression, increased frequency of KRAS mutation, and advanced cancer stage. The CIMP-L/0 MLH1m+ subtype was associated with onset at an earlier age, a predominance of MLH1 loss, and earlier cancer stage. None of the CIMP-L/0 MLH1m+ subtype patients succumbed to death during the follow-up. Our findings suggest that the discordant subtypes of colorectal cancers exhibit distinct clinicopathological and molecular features

  4. The mutational profile and infiltration pattern of murine MLH1-/- tumors: concurrences, disparities and cell line establishment for functional analysis.

    Science.gov (United States)

    Maletzki, Claudia; Beyrich, Franziska; Hühns, Maja; Klar, Ernst; Linnebacher, Michael

    2016-08-16

    Mice lines homozygous negative for one of the four DNA mismatch repair (MMR) genes (MLH1, MSH2, PMS2, MSH6) were generated as models for MMR deficient (MMR-D) diseases. Clinically, hereditary forms of MMR-D include Lynch syndrome (characterized by a germline MMR gene defect) and constitutional MMR-D, the biallelic form. MMR-D knockout mice may be representative for both diseases. Here, we aimed at characterizing the MLH1-/- model focusing on tumor-immune microenvironment and identification of coding microsatellite mutations in lymphomas and gastrointestinal tumors (GIT).All tumors showed microsatellite instability (MSI) in non-coding mononucleotide markers. Mutational profiling of 26 coding loci in MSI+ GIT and lymphomas revealed instability in half of the microsatellites, two of them (Rfc3 and Rasal2) shared between both entities. MLH1-/- tumors of both entities displayed a similar phenotype (high CD71, FasL, PD-L1 and CTLA-4 expression). Additional immunofluorescence verified the tumors' natural immunosuppressive character (marked CD11b/CD200R infiltration). Vice versa, CD3+ T cells as well as immune checkpoints molecules were detectable, indicative for an active immune microenvironment. For functional analysis, a permanent cell line from an MLH1-/- GIT was established. The newly developed MLH1-/- A7450 cells exhibit stable in vitro growth, strong invasive potential and heterogeneous drug response. Moreover, four additional MSI target genes (Nktr1, C8a, Taf1b, and Lig4) not recognized in the primary were identified in this cell line.Summing up, molecular and immunological mechanisms of MLH1-/- driven carcinogenesis correlate well with clinical features of MMR-D. MLH1-/- knockout mice combine characteristics of Lynch syndrome and constitutional MMR-D, making them suitable models for preclinical research aiming at MMR-D related diseases.

  5. BRCA2, EGFR, and NTRK mutations in mismatch repair-deficient colorectal cancers with MSH2 or MLH1 mutations.

    Science.gov (United States)

    Deihimi, Safoora; Lev, Avital; Slifker, Michael; Shagisultanova, Elena; Xu, Qifang; Jung, Kyungsuk; Vijayvergia, Namrata; Ross, Eric A; Xiu, Joanne; Swensen, Jeffrey; Gatalica, Zoran; Andrake, Mark; Dunbrack, Roland L; El-Deiry, Wafik S

    2017-06-20

    Deficient mismatch repair (MMR) and microsatellite instability (MSI) contribute to ~15% of colorectal cancer (CRCs). We hypothesized MSI leads to mutations in DNA repair proteins including BRCA2 and cancer drivers including EGFR. We analyzed mutations among a discovery cohort of 26 MSI-High (MSI-H) and 558 non-MSI-H CRCs profiled at Caris Life Sciences. Caris-profiled MSI-H CRCs had high mutation rates (50% vs 14% in non-MSI-H, P MLH1-mutant CRCs showed higher mutation rates in BRCA2 compared to non-MSH2/MLH1-mutant tumors (38% vs 6%, P MLH1-mutant CRCs included 75 unique mutations not known to occur in breast or pancreatic cancer per COSMIC v73. Only 5 deleterious BRCA2 mutations in CRC were previously reported in the BIC database as germ-line mutations in breast cancer. Some BRCA2 mutations were predicted to disrupt interactions with partner proteins DSS1 and RAD51. Some CRCs harbored multiple BRCA2 mutations. EGFR was mutated in 45.5% of MSH2/MLH1-mutant and 6.5% of non-MSH2/MLH1-mutant tumors (P MLH1-mutant CRC including NTRK1 I699V, NTRK2 P716S, and NTRK3 R745L. Our findings have clinical relevance regarding therapeutic targeting of BRCA2 vulnerabilities, EGFR mutations or other identified oncogenic drivers such as NTRK in MSH2/MLH1-mutant CRCs or other tumors with mismatch repair deficiency.

  6. Common mutations identified in the MLH1 gene in familial Lynch syndrome

    Directory of Open Access Journals (Sweden)

    Jisha Elias

    2017-12-01

    In this study we identified three families with Lynch syndrome from a rural cancer center in western India (KCHRC, Goraj, Gujarat, where 70-75 CRC patients are seen annually. DNA isolated from the blood of consented family members of all three families (8-10 members/family was subjected to NGS sequencing methods on an Illumina HiSeq 4000 platform. We identified unique mutations in the MLH1 gene in all three HNPCC family members. Two of the three unrelated families shared a common mutation (154delA and 156delA. Total 8 members of a family were identified as carriers for 156delA mutation of which 5 members were unaffected while 3 were affected (age of onset: 1 member <30yrs & 2 were>40yr. The family with 154delA mutation showed 2 affected members (>40yr carrying the mutations.LYS618DEL mutation found in 8 members of the third family showed that both affected and unaffected carried the mutation. Thus the common mutations identified in the MLH1 gene in two unrelated families had a high risk for lynch syndrome especially above the age of 40.

  7. Haplotype analysis suggest that the MLH1 c.2059C > T mutation is a Swedish founder mutation.

    Science.gov (United States)

    von Salomé, Jenny; Liu, Tao; Keihäs, Markku; Morak, Moni; Holinski-Feder, Elke; Berry, Ian R; Moilanen, Jukka S; Baert-Desurmont, Stéphanie; Lindblom, Annika; Lagerstedt-Robinson, Kristina

    2017-12-29

    Lynch syndrome (LS) predisposes to a spectrum of cancers and increases the lifetime risk of developing colorectal- or endometrial cancer to over 50%. Lynch syndrome is dominantly inherited and is caused by defects in DNA mismatch-repair genes MLH1, MSH2, MSH6 or PMS2, with the vast majority detected in MLH1 and MSH2. Recurrent LS-associated variants observed in apparently unrelated individuals, have either arisen de novo in different families due to mutation hotspots, or are inherited from a founder (a common ancestor) that lived several generations back. There are variants that recur in some populations while also acting as founders in other ethnic groups. Testing for founder mutations can facilitate molecular diagnosis of Lynch Syndrome more efficiently and more cost effective than screening for all possible mutations. Here we report a study of the missense mutation MLH1 c.2059C > T (p.Arg687Trp), a potential founder mutation identified in eight Swedish families and one Finnish family with Swedish ancestors. Haplotype analysis confirmed that the Finnish and Swedish families shared a haplotype of between 0.9 and 2.8 Mb. While MLH1 c.2059C > T exists worldwide, the Swedish haplotype was not found among mutation carriers from Germany or France, which indicates a common founder in the Swedish population. The geographic distribution of MLH1 c.2059C > T in Sweden suggests a single, ancient mutational event in the northern part of Sweden.

  8. Single nucleotide polymorphisms of DNA mismatch repair genes MSH2 and MLH1 confer susceptibility to esophageal cancer.

    Science.gov (United States)

    Sun, Ming-Zhong; Ju, Hui-Xiang; Zhou, Zhong-Wei; Jin, Hao; Zhu, Rong

    2014-01-01

    Defects in DNA mismatch repair genes like MSH2 and MLH1 confer increased risk of cancers. Here, single nucleotide polymorphisms (SNPs) in MSH2 and MLH1 were investigated for their potential contribution to the risk of esophageal cancer. This study recruited 614 participants from Affiliated Yancheng Hospital, School of Medicine, Southeast University, of which 289 were patients with esophageal cancer, and the remainder was healthy individuals who served as a control group. Two SNPs, MSH2 c.2063T>G and MLH1 IVS14-19A>G, were genotyped using PCR-RFLP. Statistical analysis was performed using chi-square test and logistic regression analysis. Carriers of the MSH2 c.2063G allele were at significantly higher risk for esophageal cancer compared to individuals with the TT genotype [OR = 3.36, 95% confidence interval (CI): 1.18-11.03]. The MLH1 IVS14-19A>G allele also conferred significantly increased (1.70-fold) for esophageal cancer compared to the AA genotype (OR = 1.70, 95% CI: 1.13-5.06). Further, the variant alleles interacted such that individuals with the susceptible genotypes at both MSH2 and MLH1 had a significantly exacerbated risk for esophageal cancer (OR = 12.38, 95% CI: 3.09-63.11). In brief, SNPs in the DNA mismatch repair genes MSH2 and MLH1 increase the risk of esophageal cancer. Molecular investigations are needed to uncover the mechanism behind their interaction effect.

  9. The Saccharomyces cerevisiae Mlh1-Mlh3 heterodimer is an endonuclease that preferentially binds to Holliday junctions.

    Science.gov (United States)

    Ranjha, Lepakshi; Anand, Roopesh; Cejka, Petr

    2014-02-28

    MutLγ, a heterodimer of the MutL homologues Mlh1 and Mlh3, plays a critical role during meiotic homologous recombination. The meiotic function of Mlh3 is fully dependent on the integrity of a putative nuclease motif DQHAX2EX4E, inferring that the anticipated nuclease activity of Mlh1-Mlh3 is involved in the processing of joint molecules to generate crossover recombination products. Although a vast body of genetic and cell biological data regarding Mlh1-Mlh3 is available, mechanistic insights into its function have been lacking due to the unavailability of the recombinant protein complex. Here we expressed the yeast Mlh1-Mlh3 heterodimer and purified it into near homogeneity. We show that recombinant MutLγ is a nuclease that nicks double-stranded DNA. We demonstrate that MutLγ binds DNA with a high affinity and shows a marked preference for Holliday junctions. We also expressed the human MLH1-MLH3 complex and show that preferential binding to Holliday junctions is a conserved capacity of eukaryotic MutLγ complexes. Specific DNA recognition has never been observed with any other eukaryotic MutL homologue. MutLγ thus represents a new paradigm for the function of the eukaryotic MutL protein family. We provide insights into the mode of Holliday junction recognition and show that Mlh1-Mlh3 prefers to bind the open unstacked Holliday junction form. This further supports the model where MutLγ is part of a complex acting on joint molecules to generate crossovers in meiosis.

  10. The Saccharomyces cerevisiae Mlh1-Mlh3 Heterodimer Is an Endonuclease That Preferentially Binds to Holliday Junctions*

    Science.gov (United States)

    Ranjha, Lepakshi; Anand, Roopesh; Cejka, Petr

    2014-01-01

    MutLγ, a heterodimer of the MutL homologues Mlh1 and Mlh3, plays a critical role during meiotic homologous recombination. The meiotic function of Mlh3 is fully dependent on the integrity of a putative nuclease motif DQHAX2EX4E, inferring that the anticipated nuclease activity of Mlh1-Mlh3 is involved in the processing of joint molecules to generate crossover recombination products. Although a vast body of genetic and cell biological data regarding Mlh1-Mlh3 is available, mechanistic insights into its function have been lacking due to the unavailability of the recombinant protein complex. Here we expressed the yeast Mlh1-Mlh3 heterodimer and purified it into near homogeneity. We show that recombinant MutLγ is a nuclease that nicks double-stranded DNA. We demonstrate that MutLγ binds DNA with a high affinity and shows a marked preference for Holliday junctions. We also expressed the human MLH1-MLH3 complex and show that preferential binding to Holliday junctions is a conserved capacity of eukaryotic MutLγ complexes. Specific DNA recognition has never been observed with any other eukaryotic MutL homologue. MutLγ thus represents a new paradigm for the function of the eukaryotic MutL protein family. We provide insights into the mode of Holliday junction recognition and show that Mlh1-Mlh3 prefers to bind the open unstacked Holliday junction form. This further supports the model where MutLγ is part of a complex acting on joint molecules to generate crossovers in meiosis. PMID:24443562

  11. Excess of extracolonic non-endometrial multiple primary cancers in MSH2 germline mutation carriers over MLH1.

    Science.gov (United States)

    Lin-Hurtubise, Kevin M; Yheulon, Christopher G; Gagliano, Ronald A; Lynch, Henry T

    2013-12-01

    The lynch syndrome (LS) tumor spectrum involves colorectal cancer (CRC), endometrial cancer (EC), and less frequently various extracolonic non-endometrial cancers (non-EC). The organ-specific survival rates of these patients are well defined, however, the collective survival of all-cancers combined (CRC + EC + non-EC) are unclear. Fifty-two MSH2 patients and 68 MLH1 patients were followed for a median of 6.3 years after diagnosis of first cancer, regardless of type. The proportions of CRC only, EC, non-EC, and multiple primary cancers were compared between the two genotypes. Kaplan-Meier curves were developed for survival comparisons. MSH2 patients present less frequently with only CRC (37% MSH2, 62% MLH1, P = 0.0096), manifest more multiple primary cancers (38% MSH2, 18% MLH1, P = 0.013), develop more extracolonic cancers (62% MSH2, 38% MLH1, P = 0.003), non-EC only cancers (46% MSH2, 24% MLH1, P = 0.028) and carry a greater risk for urinary tract cancer (UTC) (13.4% MSH2, 1.5% MLH1, P = 0.024). There was no difference in 10-year survival between the two groups (P = 0.4). The additional propensity for UTC in MSH2 carriers argues in favor of UTC screening in MSH2 individuals. Other types of cancer screening should be tailored to the expression history of the specific LS mutation. © 2013 Wiley Periodicals, Inc.

  12. Tumor-promoting phorbol esters effect alkalinization of canine renal proximal tubular cells

    International Nuclear Information System (INIS)

    Mellas, J.; Hammerman, M.R.

    1986-01-01

    We have demonstrated the presence of specific receptors for tumor-promoting phorbol esters in the plasma membrane of the canine renal proximal tubular cell. These compounds affect proximal tubular metabolism in vitro. For example, we have shown that they inhibit gluconeogenesis in canine renal proximal tubular segments. Tumor-promoting phorbol esters have been shown to effect alkalinization of non-renal cells, by enhancing Na + -H + exchange across the plasma membrane. To determine whether the actions of tumor-promoting phorbol esters in proximal tubular segments might be mediated by a similar process, we incubated suspensions of segments from dog kidney with these compounds and measured changes in intracellular pH using [ 14 C]-5,5-dimethoxazoladine-2-4-dione (DMO) and flow dialysis. Incubation of segments with phorbol 12,13 dibutyrate, but not inactive phorbol ester, 4 γ phorbol, effected alkalinization of cells within the segments in a concentration-dependent manner. Alkalinization was dependent upon the presence of extracellular [Na + ] > intracellular [Na + ], was prevented by amiloride and was demonstrable in the presence of SITS. Our findings suggest that tumor-promoting esters stimulate the Na + -H + exchanger known to be present in the brush border membrane of the renal proximal tubular cell. It is possible that the stimulation reflects a mechanism by which phorbol esters affect metabolic processes in these cells

  13. MLH1 as a direct target of MiR-155 and a potential predictor of favorable prognosis in pancreatic cancer.

    Science.gov (United States)

    Liu, Wen-Jing; Zhao, Yu-Pei; Zhang, Tai-Ping; Zhou, Li; Cui, Quan-Cai; Zhou, Wei-Xun; You, Lei; Chen, Ge; Shu, Hong

    2013-08-01

    The regulation of Mut L homologue 1 (MLH1) expression by microRNA (miR)-155 and its prognostic significance in pancreatic cancer (PC) remain to be elucidated. This study aimed to address the issues. MiR-155 mimics and inhibitor were transfected to PC cell lines, Panc-1 and Capan-1. Expression of MLH1 was subsequently evaluated. Then, luciferase activity was detected after miR-155 mimics and pRL-TK plasmids containing wild-type and mutant 3'UTRs of MLH1 mRNA were co-transfected. Finally, immunohistochemical staining for MLH1 was performed in PC samples. Transfection of miR-155 mimics and inhibitor led to reversely altered protein expressions of miR-155 and MLH1, whereas the corresponding mRNA expressions were similar. A significant decrease in luciferase activity in the cells transfected with the wild-type pRL-TK plasmid was shown in contrast to those transfected with the mutant one. In addition, MLH1 was less expressed in tumor than in para-tumor tissues of PC. Extensive MLH1 expression was significantly associated with favorable differentiation and less lymph node metastasis. MLH1 expression was found to be a prognosticator in univariate analysis, and being of marginally significant impact in multivariate test. MLH1 might serve as a direct target of miR-155 and a potential prognosis predictor in PC.

  14. The MLH1 c.-27C>A and c.85G>T variants are linked to dominantly inherited MLH1 epimutation and are borne on a European ancestral haplotype

    NARCIS (Netherlands)

    Kwok, C.T.; Vogelaar, I.P.; Zelst-Stams, W.A.G. van; Mensenkamp, A.R.; Ligtenberg, M.J.L.; Rapkins, R.W.; Ward, R.L.; Chun, N.; Ford, J.M.; Ladabaum, U.; McKinnon, W.C.; Greenblatt, M.S.; Hitchins, M.P.

    2014-01-01

    Germline mutations of the DNA mismatch repair genes MLH1, MSH2, MSH6 or PMS2, and deletions affecting the EPCAM gene adjacent to MSH2, underlie Lynch syndrome by predisposing to early-onset colorectal, endometrial and other cancers. An alternative but rare cause of Lynch syndrome is constitutional

  15. Germline mutations in PMS2 and MLH1 in individuals with solitary loss of PMS2 expression in colorectal carcinomas from the Colon Cancer Family Registry Cohort.

    Science.gov (United States)

    Rosty, Christophe; Clendenning, Mark; Walsh, Michael D; Eriksen, Stine V; Southey, Melissa C; Winship, Ingrid M; Macrae, Finlay A; Boussioutas, Alex; Poplawski, Nicola K; Parry, Susan; Arnold, Julie; Young, Joanne P; Casey, Graham; Haile, Robert W; Gallinger, Steven; Le Marchand, Loïc; Newcomb, Polly A; Potter, John D; DeRycke, Melissa; Lindor, Noralane M; Thibodeau, Stephen N; Baron, John A; Win, Aung Ko; Hopper, John L; Jenkins, Mark A; Buchanan, Daniel D

    2016-02-19

    Immunohistochemistry for DNA mismatch repair proteins is used to screen for Lynch syndrome in individuals with colorectal carcinoma (CRC). Although solitary loss of PMS2 expression is indicative of carrying a germline mutation in PMS2, previous studies reported MLH1 mutation in some cases. We determined the prevalence of MLH1 germline mutations in a large cohort of individuals with a CRC demonstrating solitary loss of PMS2 expression. This cohort study included 88 individuals affected with a PMS2-deficient CRC from the Colon Cancer Family Registry Cohort. Germline PMS2 mutation analysis (long-range PCR and multiplex ligation-dependent probe amplification) was followed by MLH1 mutation testing (Sanger sequencing and multiplex ligation-dependent probe amplification). Of the 66 individuals with complete mutation screening, we identified a pathogenic PMS2 mutation in 49 (74%), a pathogenic MLH1 mutation in 8 (12%) and a MLH1 variant of uncertain clinical significance predicted to be damaging by in silico analysis in 3 (4%); 6 (9%) carried variants likely to have no clinical significance. Missense point mutations accounted for most alterations (83%; 9/11) in MLH1. The MLH1 c.113A> G p.Asn38Ser mutation was found in 2 related individuals. One individual who carried the MLH1 intronic mutation c.677+3A>G p.Gln197Argfs*8 leading to the skipping of exon 8, developed 2 tumours, both of which retained MLH1 expression. A substantial proportion of CRCs with solitary loss of PMS2 expression are associated with a deleterious MLH1 germline mutation supporting the screening for MLH1 in individuals with tumours of this immunophenotype, when no PMS2 mutation has been identified. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  16. Impact of MLH1 expression on tumor evolution after curative surgical tumor resection in a murine orthotopic xenograft model for human MSI colon cancer.

    Science.gov (United States)

    Meunier, Katy; Ferron, Marianne; Calmel, Claire; Fléjou, Jean-François; Pocard, Marc; Praz, Françoise

    2017-09-01

    Colorectal cancers (CRCs) displaying microsatellite instability (MSI) most often result from MLH1 deficiency. The aim of this study was to assess the impact of MLH1 expression per se on tumor evolution after curative surgical resection using a xenograft tumor model. Transplantable tumors established with the human MLH1-deficient HCT116 cell line and its MLH1-complemented isogenic clone, mlh1-3, were implanted onto the caecum of NOD/SCID mice. Curative surgical resection was performed at day 10 in half of the animals. The HCT116-derived tumors were more voluminous compared to the mlh1-3 ones (P = .001). Lymph node metastases and peritoneal carcinomatosis occurred significantly more often in the group of mice grafted with HCT116 (P = .007 and P = .035, respectively). Mlh1-3-grafted mice did not develop peritoneal carcinomatosis or liver metastasis. After surgical resection, lymph node metastases only arose in the group of mice implanted with HCT116 and the rate of cure was significantly lower than in the mlh1-3 group (P = .047). The murine orthotopic xenograft model based on isogenic human CRC cell lines allowed us to reveal the impact of MLH1 expression on tumor evolution in mice who underwent curative surgical resection and in mice whose tumor was left in situ. Our data indicate that the behavior of MLH1-deficient CRC is not only governed by mutations arising in genes harboring microsatellite repeated sequences but also from their defect in MLH1 as such. © 2017 Wiley Periodicals, Inc.

  17. Fruits, vegetables and hMLH1 protein-deficient and-proficient colon cancer: the Netherlands Cohort Study

    NARCIS (Netherlands)

    Wark, P.A.; Weijenberg, M.P.; Veer, van 't P.; Wijhe, van G.; Luchtenborg, M.; Muijen, van G.N.P.; Goeij, de A.F.P.M.; Goldbohm, R.A.; Brandt, van den P.A.

    2005-01-01

    Clinical and pathologic differences exist between colon carcinomas deficient and proficient in the mismatch repair protein hMLH1. Animal and in vitro studies suggest that fruits, vegetables, folate, and antioxidants are associated with colonic expression of mismatch repair genes.METHODS:

  18. Functional examination of MLH1, MSH2, and MSH6 intronic mutations identified in Danish colorectal cancer patients

    DEFF Research Database (Denmark)

    Petersen, Sanne M; Dandanell, Mette; Rasmussen, Lene J

    2013-01-01

    Germ-line mutations in the DNA mismatch repair genes MLH1, MSH2, and MSH6 predispose to the development of colorectal cancer (Lynch syndrome or hereditary nonpolyposis colorectal cancer). These mutations include disease-causing frame-shift, nonsense, and splicing mutations as well as large genomi...

  19. First description of mutational analysis of MLH1, MSH2 and MSH6 in Algerian families with suspected Lynch syndrome.

    Science.gov (United States)

    Ziada-Bouchaar, H; Sifi, K; Filali, T; Hammada, T; Satta, D; Abadi, N

    2017-01-01

    Hereditary non-polyposis colorectal cancer (HNPCC) is an autosomal dominant disorder characterized by the early onset of colorectal cancer (CRC) linked to germline defects in Mismatch Repair (MMR) genes. We present here, the first molecular study of the correlation between CRC and mutations occurring in these genes performed in twenty-one unrelated Algerian families. The presence of germline mutations in MMR genes, MLH1, MSH2 and MSH6 genes was tested by sequencing all exons plus adjacent intronic sequences and Multiplex ligand-dependent probe amplification (MLPA) for testing large genomic rearrangements. Pathogenic mutations were identified in 20 % of families with clinical suspicion on HNPCC. Two novel variants described for the first time in Algerian families were identified in MLH1, c.881_884delTCAGinsCATTCCT and a large deletion in MSH6 gene from a young onset of CRC. Moreover, the variants of MSH2 gene: c.942+3A>T, c.1030C>T, the most described ones, were also detected in Algerian families. Furthermore, the families HNPCC caused by MSH6 germline mutation may show an age of onset that is comparable to this of patients with MLH1 and MSH2 mutations. In this study, we confirmed that MSH2, MLH1, and MSH6 contribute to CRC susceptibility. This work represents the implementation of a diagnostic algorithm for the identification of Lynch syndrome patients in Algerian families.

  20. Dietary fat and risk of colon and rectal cancer with aberrant MLH1 expression, APC or KRAS genes.

    NARCIS (Netherlands)

    Weijenberg, M.P.; Luchtenborg, M.; Goeij, A.F. de; Brink, M.; Muijen, G.N.P. van; Bruine, A.P. de; Goldbohm, R.A.; Brandt, P.A. van den

    2007-01-01

    OBJECTIVE: To investigate baseline fat intake and the risk of colon and rectal tumors lacking MLH1 (mutL homolog 1, colon cancer, nonpolyposis type 2) repair gene expression and harboring mutations in the APC (adenomatous polyposis coli) tumor suppressor gene and in the KRAS (v-Ki-ras2 Kirsten rat

  1. Dietary fat and risk of colon and rectal cancer with aberrant MLH1 expression, APC or KRAS genes.

    Science.gov (United States)

    Weijenberg, Matty P; Lüchtenborg, Margreet; de Goeij, Anton F P M; Brink, Mirian; van Muijen, Goos N P; de Bruïne, Adriaan P; Goldbohm, R Alexandra; van den Brandt, Piet A

    2007-10-01

    To investigate baseline fat intake and the risk of colon and rectal tumors lacking MLH1 (mutL homolog 1, colon cancer, nonpolyposis type 2) repair gene expression and harboring mutations in the APC (adenomatous polyposis coli) tumor suppressor gene and in the KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) oncogene. After 7.3 years of follow-up of the Netherlands Cohort Study (n = 120,852), adjusted incidence rate ratios (RR) and 95% confidence intervals (CI) were computed, based on 401 colon and 130 rectal cancer patients. Total, saturated and monounsaturated fat were not associated with the risk of colon or rectal cancer, or different molecular subgroups. There was also no association between polyunsaturated fat and the risk of overall or subgroups of rectal cancer. Linoleic acid, the most abundant polyunsaturated fatty acid in the diet, was associated with increased risk of colon tumors with only a KRAS mutation and no additional truncating APC mutation or lack of MLH1 expression (RR = 1.41, 95% CI 1.18-1.69 for one standard deviation (i.e., 7.5 g/day) increase in intake, p-trend over the quartiles of intake colon tumors without any of the gene defects, or with tumors harboring aberrations in either MLH1 or APC. Linoleic acid intake is associated with colon tumors with an aberrant KRAS gene, but an intact APC gene and MLH1 expression, suggesting a unique etiology of tumors with specific genetic aberrations.

  2. Partial loss of heterozygosity events at the mutated gene in tumors from MLH1/MSH2 large genomic rearrangement carriers

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    Zavodna, Katarina; Krivulcik, Tomas; Bujalkova, Maria Gerykova [Laboratory of Cancer Genetics, Cancer Research Institute of Slovak Academy of Sciences, Vlarska 7, 833 91 Bratislava (Slovakia); Slamka, Tomas; Martinicky, David; Ilencikova, Denisa [National Cancer Institute, Department of Oncologic Genetics, Klenova 1, 833 01 Bratislava (Slovakia); Bartosova, Zdena [Laboratory of Cancer Genetics, Cancer Research Institute of Slovak Academy of Sciences, Vlarska 7, 833 91 Bratislava (Slovakia)

    2009-11-20

    Depending on the population studied, large genomic rearrangements (LGRs) of the mismatch repair (MMR) genes constitute various proportions of the germline mutations that predispose to hereditary non-polyposis colorectal cancer (HNPCC). It has been reported that loss of heterozygosity (LOH) at the LGR region occurs through a gene conversion mechanism in tumors from MLH1/MSH2 deletion carriers; however, the converted tracts were delineated only by extragenic microsatellite markers. We sought to determine the frequency of LGRs in Slovak HNPCC patients and to study LOH in tumors from LGR carriers at the LGR region, as well as at other heterozygous markers within the gene to more precisely define conversion tracts. The main MMR genes responsible for HNPCC, MLH1, MSH2, MSH6, and PMS2, were analyzed by MLPA (multiplex ligation-dependent probe amplification) in a total of 37 unrelated HNPCC-suspected patients whose MLH1/MSH2 genes gave negative results in previous sequencing experiments. An LOH study was performed on six tumors from LGR carriers by combining MLPA to assess LOH at LGR regions and sequencing to examine LOH at 28 SNP markers from the MLH1 and MSH2 genes. We found six rearrangements in the MSH2 gene (five deletions and dup5-6), and one aberration in the MLH1 gene (del5-6). The MSH2 deletions were of three types (del1, del1-3, del1-7). We detected LOH at the LGR region in the single MLH1 case, which was determined in a previous study to be LOH-negative in the intragenic D3S1611 marker. Three tumors displayed LOH of at least one SNP marker, including two cases that were LOH-negative at the LGR region. LGRs accounted for 25% of germline MMR mutations identified in 28 Slovakian HNPCC families. A high frequency of LGRs among the MSH2 mutations provides a rationale for a MLPA screening of the Slovakian HNPCC families prior scanning by DNA sequencing. LOH at part of the informative loci confined to the MLH1 or MSH2 gene (heterozygous LGR region, SNP, or

  3. Partial loss of heterozygosity events at the mutated gene in tumors from MLH1/MSH2 large genomic rearrangement carriers

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    Ilencikova Denisa

    2009-11-01

    Full Text Available Abstract Background Depending on the population studied, large genomic rearrangements (LGRs of the mismatch repair (MMR genes constitute various proportions of the germline mutations that predispose to hereditary non-polyposis colorectal cancer (HNPCC. It has been reported that loss of heterozygosity (LOH at the LGR region occurs through a gene conversion mechanism in tumors from MLH1/MSH2 deletion carriers; however, the converted tracts were delineated only by extragenic microsatellite markers. We sought to determine the frequency of LGRs in Slovak HNPCC patients and to study LOH in tumors from LGR carriers at the LGR region, as well as at other heterozygous markers within the gene to more precisely define conversion tracts. Methods The main MMR genes responsible for HNPCC, MLH1, MSH2, MSH6, and PMS2, were analyzed by MLPA (multiplex ligation-dependent probe amplification in a total of 37 unrelated HNPCC-suspected patients whose MLH1/MSH2 genes gave negative results in previous sequencing experiments. An LOH study was performed on six tumors from LGR carriers by combining MLPA to assess LOH at LGR regions and sequencing to examine LOH at 28 SNP markers from the MLH1 and MSH2 genes. Results We found six rearrangements in the MSH2 gene (five deletions and dup5-6, and one aberration in the MLH1 gene (del5-6. The MSH2 deletions were of three types (del1, del1-3, del1-7. We detected LOH at the LGR region in the single MLH1 case, which was determined in a previous study to be LOH-negative in the intragenic D3S1611 marker. Three tumors displayed LOH of at least one SNP marker, including two cases that were LOH-negative at the LGR region. Conclusion LGRs accounted for 25% of germline MMR mutations identified in 28 Slovakian HNPCC families. A high frequency of LGRs among the MSH2 mutations provides a rationale for a MLPA screening of the Slovakian HNPCC families prior scanning by DNA sequencing. LOH at part of the informative loci confined to the MLH1

  4. Partial loss of heterozygosity events at the mutated gene in tumors from MLH1/MSH2 large genomic rearrangement carriers

    International Nuclear Information System (INIS)

    Zavodna, Katarina; Krivulcik, Tomas; Bujalkova, Maria Gerykova; Slamka, Tomas; Martinicky, David; Ilencikova, Denisa; Bartosova, Zdena

    2009-01-01

    Depending on the population studied, large genomic rearrangements (LGRs) of the mismatch repair (MMR) genes constitute various proportions of the germline mutations that predispose to hereditary non-polyposis colorectal cancer (HNPCC). It has been reported that loss of heterozygosity (LOH) at the LGR region occurs through a gene conversion mechanism in tumors from MLH1/MSH2 deletion carriers; however, the converted tracts were delineated only by extragenic microsatellite markers. We sought to determine the frequency of LGRs in Slovak HNPCC patients and to study LOH in tumors from LGR carriers at the LGR region, as well as at other heterozygous markers within the gene to more precisely define conversion tracts. The main MMR genes responsible for HNPCC, MLH1, MSH2, MSH6, and PMS2, were analyzed by MLPA (multiplex ligation-dependent probe amplification) in a total of 37 unrelated HNPCC-suspected patients whose MLH1/MSH2 genes gave negative results in previous sequencing experiments. An LOH study was performed on six tumors from LGR carriers by combining MLPA to assess LOH at LGR regions and sequencing to examine LOH at 28 SNP markers from the MLH1 and MSH2 genes. We found six rearrangements in the MSH2 gene (five deletions and dup5-6), and one aberration in the MLH1 gene (del5-6). The MSH2 deletions were of three types (del1, del1-3, del1-7). We detected LOH at the LGR region in the single MLH1 case, which was determined in a previous study to be LOH-negative in the intragenic D3S1611 marker. Three tumors displayed LOH of at least one SNP marker, including two cases that were LOH-negative at the LGR region. LGRs accounted for 25% of germline MMR mutations identified in 28 Slovakian HNPCC families. A high frequency of LGRs among the MSH2 mutations provides a rationale for a MLPA screening of the Slovakian HNPCC families prior scanning by DNA sequencing. LOH at part of the informative loci confined to the MLH1 or MSH2 gene (heterozygous LGR region, SNP, or

  5. Vitamin E Modifies High-Fat Diet-Induced Increase of DNA Strand Breaks, and Changes in Expression and DNA Methylation of Dnmt1 and MLH1 in C57BL/6J Male Mice

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    Marlene Remely

    2017-06-01

    Full Text Available Obesity is associated with low-grade inflammation, increased ROS production and DNA damage. Supplementation with antioxidants might ameliorate DNA damage and support epigenetic regulation of DNA repair. C57BL/6J male mice were fed a high-fat (HFD or a control diet (CD with and without vitamin E supplementation (4.5 mg/kg body weight (b.w. for four months. DNA damage, DNA promoter methylation and gene expression of Dnmt1 and a DNA repair gene (MLH1 were assayed in liver and colon. The HFD resulted in organ specific changes in DNA damage, the epigenetically important Dnmt1 gene, and the DNA repair gene MLH1. Vitamin E reduced DNA damage and showed organ-specific effects on MLH1 and Dnmt1 gene expression and methylation. These results suggest that interventions with antioxidants and epigenetic active food ingredients should be developed as an effective prevention for obesity—and oxidative stress—induced health risks.

  6. Vitamin E Modifies High-Fat Diet-Induced Increase of DNA Strand Breaks, and Changes in Expression and DNA Methylation of Dnmt1 and MLH1 in C57BL/6J Male Mice.

    Science.gov (United States)

    Remely, Marlene; Ferk, Franziska; Sterneder, Sonja; Setayesh, Tahereh; Kepcija, Tatjana; Roth, Sylvia; Noorizadeh, Rahil; Greunz, Martina; Rebhan, Irene; Wagner, Karl-Heinz; Knasmüller, Siegfried; Haslberger, Alexander

    2017-06-14

    Obesity is associated with low-grade inflammation, increased ROS production and DNA damage. Supplementation with antioxidants might ameliorate DNA damage and support epigenetic regulation of DNA repair. C57BL/6J male mice were fed a high-fat (HFD) or a control diet (CD) with and without vitamin E supplementation (4.5 mg/kg body weight (b.w.)) for four months. DNA damage, DNA promoter methylation and gene expression of Dnmt1 and a DNA repair gene ( MLH1 ) were assayed in liver and colon. The HFD resulted in organ specific changes in DNA damage, the epigenetically important Dnmt1 gene, and the DNA repair gene MLH1 . Vitamin E reduced DNA damage and showed organ-specific effects on MLH1 and Dnmt1 gene expression and methylation. These results suggest that interventions with antioxidants and epigenetic active food ingredients should be developed as an effective prevention for obesity-and oxidative stress-induced health risks.

  7. Genetic changes of MLH1 and MSH2 genes could explain constant findings on microsatellite instability in intracranial meningioma.

    Science.gov (United States)

    Pećina-Šlaus, Nives; Kafka, Anja; Bukovac, Anja; Vladušić, Tomislav; Tomas, Davor; Hrašćan, Reno

    2017-07-01

    Postreplicative mismatch repair safeguards the stability of our genome. The defects in its functioning will give rise to microsatellite instability. In this study, 50 meningiomas were investigated for microsatellite instability. Two major mismatch repair genes, MLH1 and MSH2, were analyzed using microsatellite markers D1S1611 and BAT26 amplified by polymerase chain reaction and visualized by gel electrophoresis on high-resolution gels. Furthermore, genes DVL3 (D3S1262), AXIN1 (D16S3399), and CDH1 (D16S752) were also investigated for microsatellite instability. Our study revealed constant presence of microsatellite instability in meningioma patients when compared to their autologous blood DNA. Altogether 38% of meningiomas showed microsatellite instability at one microsatellite locus, 16% on two, and 13.3% on three loci. The percent of detected microsatellite instability for MSH2 gene was 14%, and for MLH1, it was 26%, for DVL3 22.9%, for AXIN1 17.8%, and for CDH1 8.3%. Since markers also allowed for the detection of loss of heterozygosity, gross deletions of MLH1 gene were found in 24% of meningiomas. Genetic changes between MLH1 and MSH2 were significantly positively correlated (p = 0.032). We also noted a positive correlation between genetic changes of MSH2 and DVL3 genes (p = 0.034). No significant associations were observed when MLH1 or MSH2 was tested against specific histopathological meningioma subtype or World Health Organization grade. However, genetic changes in DVL3 were strongly associated with anaplastic histology of meningioma (χ 2  = 9.14; p = 0.01). Our study contributes to better understanding of the genetic profile of human intracranial meningiomas and suggests that meningiomas harbor defective cellular DNA mismatch repair mechanisms.

  8. Performance of Lynch syndrome predictive models in quantifying the likelihood of germline mutations in patients with abnormal MLH1 immunoexpression.

    Science.gov (United States)

    Cabreira, Verónica; Pinto, Carla; Pinheiro, Manuela; Lopes, Paula; Peixoto, Ana; Santos, Catarina; Veiga, Isabel; Rocha, Patrícia; Pinto, Pedro; Henrique, Rui; Teixeira, Manuel R

    2017-01-01

    Lynch syndrome (LS) accounts for up to 4 % of all colorectal cancers (CRC). Detection of a pathogenic germline mutation in one of the mismatch repair genes is the definitive criterion for LS diagnosis, but it is time-consuming and expensive. Immunohistochemistry is the most sensitive prescreening test and its predictive value is very high for loss of expression of MSH2, MSH6, and (isolated) PMS2, but not for MLH1. We evaluated if LS predictive models have a role to improve the molecular testing algorithm in this specific setting by studying 38 individuals referred for molecular testing and who were subsequently shown to have loss of MLH1 immunoexpression in their tumors. For each proband we calculated a risk score, which represents the probability that the patient with CRC carries a pathogenic MLH1 germline mutation, using the PREMM 1,2,6 and MMRpro predictive models. Of the 38 individuals, 18.4 % had a pathogenic MLH1 germline mutation. MMRpro performed better for the purpose of this study, presenting a AUC of 0.83 (95 % CI 0.67-0.9; P < 0.001) compared with a AUC of 0.68 (95 % CI 0.51-0.82, P = 0.09) for PREMM 1,2,6 . Considering a threshold of 5 %, MMRpro would eliminate unnecessary germline mutation analysis in a significant proportion of cases while keeping very high sensitivity. We conclude that MMRpro is useful to correctly predict who should be screened for a germline MLH1 gene mutation and propose an algorithm to improve the cost-effectiveness of LS diagnosis.

  9. Cancer risk in MLH1, MSH2 and MSH6 mutation carriers; different risk profiles may influence clinical management

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    Ramsoekh Dewkoemar

    2009-12-01

    Full Text Available Abstract Background Lynch syndrome (LS is associated with a high risk for colorectal cancer (CRC and extracolonic malignancies, such as endometrial carcinoma (EC. The risk is dependent of the affected mismatch repair gene. The aim of the present study was to calculate the cumulative risk of LS related cancers in proven MLH1, MSH2 and MSH6 mutation carriers. Methods The studypopulation consisted out of 67 proven LS families. Clinical information including mutation status and tumour diagnosis was collected. Cumulative risks were calculated and compared using Kaplan Meier survival analysis. Results MSH6 mutation carriers, both males and females had the lowest risk for developing CRC at age 70 years, 54% and 30% respectively and the age of onset was delayed by 3-5 years in males. With respect to endometrial carcinoma, female MSH6 mutation carriers had the highest risk at age 70 years (61% compared to MLH1 (25% and MSH2 (49%. Also, the age of EC onset was delayed by 5-10 years in comparison with MLH1 and MSH2. Conclusions Although the cumulative lifetime risk of LS related cancer is similar, MLH1, MSH2 and MSH6 mutations seem to cause distinguishable cancer risk profiles. Female MSH6 mutation carriers have a lower CRC risk and a higher risk for developing endometrial carcinoma. As a consequence, surveillance colonoscopy starting at age 30 years instead of 20-25 years is more suitable. Also, prophylactic hysterectomy may be more indicated in female MSH6 mutation carriers compared to MLH1 and MSH2 mutation carriers.

  10. Colorectal cancer incidence in path_MLH1 carriers subjected to different follow-up protocols : A Prospective Lynch Syndrome Database report

    NARCIS (Netherlands)

    Seppala, Toni; Pylvanainen, Kirsi; Evans, Dafydd Gareth; Jarvinen, Heikki; Renkonen-Sinisalo, Laura; Bernstein, Inge; Holinski-Feder, Elke; Sala, Paola; Lindblom, Annika; Macrae, Finlay; Blanco, Ignacio; Sijmons, Rolf; Jeffries, Jacqueline; Vasen, Hans; Burn, John; Nakken, Sigve; Hovig, Eivind; Rodland, Einar Andreas; Tharmaratnam, Kukatharmini; Cappel, Wouter H. de Vos tot Nederveen; Hill, James; Wijnen, Juul; Jenkins, Mark; Genuardi, Maurizio; Green, Kate; Lalloo, Fiona; Sunde, Lone; Mints, Miriam; Bertario, Lucio; Pineda, Marta; Navarro, Matilde; Morak, Monika; Frayling, Ian M.; Plazzer, John-Paul; Sampson, Julian R.; Capella, Gabriel; Moslein, Gabriela; Mecklin, Jukka-Pekka; Moller, Pal

    2017-01-01

    BACKGROUND: We have previously reported a high incidence of colorectal cancer (CRC) in carriers of pathogenicMLH1variants(path_MLH1) despite follow-up with colonoscopy including polypectomy. METHODS: The cohort included Finnish carriers enrolled in 3-yearly colonoscopy (n = 505; 4625 observation

  11. High frequency induction of mitotic recombination by ionizing radiation in Mlh1 null mouse cells

    International Nuclear Information System (INIS)

    Wang Qi; Ponomareva, Olga N.; Lasarev, Michael; Turker, Mitchell S.

    2006-01-01

    Mitotic recombination in somatic cells involves crossover events between homologous autosomal chromosomes. This process can convert a cell with a heterozygous deficiency to one with a homozygous deficiency if a mutant allele is present on one of the two homologous autosomes. Thus mitotic recombination often represents the second mutational step in tumor suppressor gene inactivation. In this study we examined the frequency and spectrum of ionizing radiation (IR)-induced autosomal mutations affecting Aprt expression in a mouse kidney cell line null for the Mlh1 mismatch repair (MMR) gene. The mutant frequency results demonstrated high frequency induction of mutations by IR exposure and the spectral analysis revealed that most of this response was due to the induction of mitotic recombinational events. High frequency induction of mitotic recombination was not observed in a DNA repair-proficient cell line or in a cell line with an MMR-independent mutator phenotype. These results demonstrate that IR exposure can initiate a process leading to mitotic recombinational events and that MMR function suppresses these events from occurring

  12. Identification and verification of a pathogenic MLH1 mutation c.1145dupA in a Lynch syndrome family

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    Huang Feifei

    2017-06-01

    Full Text Available Lynch syndrome (LS, an autosomal-dominant disorder with an increased risk of predominantly colorectal and endometrial cancers, is caused by germ-line mutations in mismatch repair genes. The identification of germ-line mutations that predispose to cancer is important to further our understanding of tumorigenesis, guide patient management and inform the best practice for healthcare. A 45-year-old woman with atypical endometrial hyperplasia who suffered colon cancer at the age of 30 years underwent hysterectomy and genetic counseling. Pedigree analysis revealed her family fulfilling the Amsterdam I criteria. Next-generation sequencing was offered to the patient. A mutation in the MLH1 gene, c.1145dupA, was identified and verified by Sanger sequencing. In addition, her nine family members were tested for the mutation. Two were affected (colon cancer at the age of 43 years and 45 years and one healthy relative carried the same mutation in the MLH1 gene. The mutation resulted in a frame-shift (p.Met383Aspfs*12 located in exon12, as well as a polypeptide truncation of 393 amino acids by the formation of a premature stop codon. An immunohistochemistry analysis of endometrial hyperplasia tissues revealed defects in MLH1 and PMS2 protein expression in the patient. Based on the 2015 American College of Medical Genetics and Genomics (ACMG guideline, we report this MLH1 c.1145dupA variation to be a pathogenic mutation that contributes to a strongly increased cancer risk in this LS family. Proper screening suggestions were offered to the three affected patients and the healthy carrier. To the best of our knowledge, this germ-line mutation of MLH1 was previously submitted to the Leiden Open Variation Database (LOVD database, but no comprehensive evidence or supporting observations were reported previously in the literature. The present report found a single nucleotide insertion in exon12 of the MLH1 gene, which can be considered causative of Lynch phenotype

  13. Mismatch repair genes Mlh1 and Mlh3 modify CAG instability in Huntington's disease mice: genome-wide and candidate approaches.

    Science.gov (United States)

    Pinto, Ricardo Mouro; Dragileva, Ella; Kirby, Andrew; Lloret, Alejandro; Lopez, Edith; St Claire, Jason; Panigrahi, Gagan B; Hou, Caixia; Holloway, Kim; Gillis, Tammy; Guide, Jolene R; Cohen, Paula E; Li, Guo-Min; Pearson, Christopher E; Daly, Mark J; Wheeler, Vanessa C

    2013-10-01

    The Huntington's disease gene (HTT) CAG repeat mutation undergoes somatic expansion that correlates with pathogenesis. Modifiers of somatic expansion may therefore provide routes for therapies targeting the underlying mutation, an approach that is likely applicable to other trinucleotide repeat diseases. Huntington's disease Hdh(Q111) mice exhibit higher levels of somatic HTT CAG expansion on a C57BL/6 genetic background (B6.Hdh(Q111) ) than on a 129 background (129.Hdh(Q111) ). Linkage mapping in (B6x129).Hdh(Q111) F2 intercross animals identified a single quantitative trait locus underlying the strain-specific difference in expansion in the striatum, implicating mismatch repair (MMR) gene Mlh1 as the most likely candidate modifier. Crossing B6.Hdh(Q111) mice onto an Mlh1 null background demonstrated that Mlh1 is essential for somatic CAG expansions and that it is an enhancer of nuclear huntingtin accumulation in striatal neurons. Hdh(Q111) somatic expansion was also abolished in mice deficient in the Mlh3 gene, implicating MutLγ (MLH1-MLH3) complex as a key driver of somatic expansion. Strikingly, Mlh1 and Mlh3 genes encoding MMR effector proteins were as critical to somatic expansion as Msh2 and Msh3 genes encoding DNA mismatch recognition complex MutSβ (MSH2-MSH3). The Mlh1 locus is highly polymorphic between B6 and 129 strains. While we were unable to detect any difference in base-base mismatch or short slipped-repeat repair activity between B6 and 129 MLH1 variants, repair efficiency was MLH1 dose-dependent. MLH1 mRNA and protein levels were significantly decreased in 129 mice compared to B6 mice, consistent with a dose-sensitive MLH1-dependent DNA repair mechanism underlying the somatic expansion difference between these strains. Together, these data identify Mlh1 and Mlh3 as novel critical genetic modifiers of HTT CAG instability, point to Mlh1 genetic variation as the likely source of the instability difference in B6 and 129 strains and suggest that MLH1

  14. Mismatch repair genes Mlh1 and Mlh3 modify CAG instability in Huntington's disease mice: genome-wide and candidate approaches.

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    Ricardo Mouro Pinto

    2013-10-01

    Full Text Available The Huntington's disease gene (HTT CAG repeat mutation undergoes somatic expansion that correlates with pathogenesis. Modifiers of somatic expansion may therefore provide routes for therapies targeting the underlying mutation, an approach that is likely applicable to other trinucleotide repeat diseases. Huntington's disease Hdh(Q111 mice exhibit higher levels of somatic HTT CAG expansion on a C57BL/6 genetic background (B6.Hdh(Q111 than on a 129 background (129.Hdh(Q111 . Linkage mapping in (B6x129.Hdh(Q111 F2 intercross animals identified a single quantitative trait locus underlying the strain-specific difference in expansion in the striatum, implicating mismatch repair (MMR gene Mlh1 as the most likely candidate modifier. Crossing B6.Hdh(Q111 mice onto an Mlh1 null background demonstrated that Mlh1 is essential for somatic CAG expansions and that it is an enhancer of nuclear huntingtin accumulation in striatal neurons. Hdh(Q111 somatic expansion was also abolished in mice deficient in the Mlh3 gene, implicating MutLγ (MLH1-MLH3 complex as a key driver of somatic expansion. Strikingly, Mlh1 and Mlh3 genes encoding MMR effector proteins were as critical to somatic expansion as Msh2 and Msh3 genes encoding DNA mismatch recognition complex MutSβ (MSH2-MSH3. The Mlh1 locus is highly polymorphic between B6 and 129 strains. While we were unable to detect any difference in base-base mismatch or short slipped-repeat repair activity between B6 and 129 MLH1 variants, repair efficiency was MLH1 dose-dependent. MLH1 mRNA and protein levels were significantly decreased in 129 mice compared to B6 mice, consistent with a dose-sensitive MLH1-dependent DNA repair mechanism underlying the somatic expansion difference between these strains. Together, these data identify Mlh1 and Mlh3 as novel critical genetic modifiers of HTT CAG instability, point to Mlh1 genetic variation as the likely source of the instability difference in B6 and 129 strains and suggest

  15. Detailed characterization of MLH1 p.D41H and p.N710D variants coexisting in a Lynch syndrome family with conserved MLH1 expression tumors.

    Science.gov (United States)

    Pineda, M; González-Acosta, M; Thompson, B A; Sánchez, R; Gómez, C; Martínez-López, J; Perea, J; Caldés, T; Rodríguez, Y; Landolfi, S; Balmaña, J; Lázaro, C; Robles, L; Capellá, G; Rueda, D

    2015-06-01

    Lynch syndrome (LS) is an autosomal dominant cancer-susceptibility disease caused by inactivating germline mutations in mismatch repair (MMR) genes. Variants of unknown significance (VUS) are often detected in mutational analysis of MMR genes. Here we describe a large family fulfilling Amsterdam I criteria carrying two rare VUS in the MLH1 gene: c.121G > C (p.D41H) and c.2128A > G (p.N710D). Collection of clinico-pathological data, multifactorial analysis, in silico predictions, and functional analyses were used to elucidate the clinical significance of the identified MLH1 VUS. Only the c.121G > C variant cosegregated with LS-associated tumors in the family. Diagnosed colorectal tumors were microsatellite unstable although immunohistochemical staining revealed no loss of MMR proteins expression. Multifactorial likelihood analysis classified c.2128A > G as a non-pathogenic variant and c.121G > C as pathogenic. In vitro functional tests revealed impaired MMR activity and diminished expression of c.121G > C. Accordingly, the N710 residue is located in the unconserved MLH1 C-terminal domain, whereas D41 is highly conserved and located in the ATPase domain. The obtained results will enable adequate genetic counseling of c.121G > C and c.2128A > G variant carriers and their families. Furthermore, they exemplify how cumulative data and comprehensive analyses are mandatory to refine the classification of MMR variants. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Dominant mutations in S. cerevisiae PMS1 identify the Mlh1-Pms1 endonuclease active site and an exonuclease 1-independent mismatch repair pathway.

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    Catherine E Smith

    2013-10-01

    Full Text Available Lynch syndrome (hereditary nonpolypsis colorectal cancer or HNPCC is a common cancer predisposition syndrome. Predisposition to cancer in this syndrome results from increased accumulation of mutations due to defective mismatch repair (MMR caused by a mutation in one of the mismatch repair genes MLH1, MSH2, MSH6 or PMS2/scPMS1. To better understand the function of Mlh1-Pms1 in MMR, we used Saccharomyces cerevisiae to identify six pms1 mutations (pms1-G683E, pms1-C817R, pms1-C848S, pms1-H850R, pms1-H703A and pms1-E707A that were weakly dominant in wild-type cells, which surprisingly caused a strong MMR defect when present on low copy plasmids in an exo1Δ mutant. Molecular modeling showed these mutations caused amino acid substitutions in the metal coordination pocket of the Pms1 endonuclease active site and biochemical studies showed that they inactivated the endonuclease activity. This model of Mlh1-Pms1 suggested that the Mlh1-FERC motif contributes to the endonuclease active site. Consistent with this, the mlh1-E767stp mutation caused both MMR and endonuclease defects similar to those caused by the dominant pms1 mutations whereas mutations affecting the predicted metal coordinating residue Mlh1-C769 had no effect. These studies establish that the Mlh1-Pms1 endonuclease is required for MMR in a previously uncharacterized Exo1-independent MMR pathway.

  17. Dominant mutations in S. cerevisiae PMS1 identify the Mlh1-Pms1 endonuclease active site and an exonuclease 1-independent mismatch repair pathway.

    Science.gov (United States)

    Smith, Catherine E; Mendillo, Marc L; Bowen, Nikki; Hombauer, Hans; Campbell, Christopher S; Desai, Arshad; Putnam, Christopher D; Kolodner, Richard D

    2013-10-01

    Lynch syndrome (hereditary nonpolypsis colorectal cancer or HNPCC) is a common cancer predisposition syndrome. Predisposition to cancer in this syndrome results from increased accumulation of mutations due to defective mismatch repair (MMR) caused by a mutation in one of the mismatch repair genes MLH1, MSH2, MSH6 or PMS2/scPMS1. To better understand the function of Mlh1-Pms1 in MMR, we used Saccharomyces cerevisiae to identify six pms1 mutations (pms1-G683E, pms1-C817R, pms1-C848S, pms1-H850R, pms1-H703A and pms1-E707A) that were weakly dominant in wild-type cells, which surprisingly caused a strong MMR defect when present on low copy plasmids in an exo1Δ mutant. Molecular modeling showed these mutations caused amino acid substitutions in the metal coordination pocket of the Pms1 endonuclease active site and biochemical studies showed that they inactivated the endonuclease activity. This model of Mlh1-Pms1 suggested that the Mlh1-FERC motif contributes to the endonuclease active site. Consistent with this, the mlh1-E767stp mutation caused both MMR and endonuclease defects similar to those caused by the dominant pms1 mutations whereas mutations affecting the predicted metal coordinating residue Mlh1-C769 had no effect. These studies establish that the Mlh1-Pms1 endonuclease is required for MMR in a previously uncharacterized Exo1-independent MMR pathway.

  18. The mRNA level of MLH1 in peripheral blood is a biomarker for the diagnosis of hereditary nonpolyposis colorectal cancer.

    Science.gov (United States)

    Yu, Hong; Li, Hui; Cui, Yongan; Xiao, Wei; Dai, Guihong; Huang, Junxing; Wang, Chaofu

    2016-01-01

    Hereditary nonpolyposis colorectal cancer (HNPCC) is caused by functional defects in mismatch repair (MMR) genes, including mutL homolog 1 (MLH1) and mutS homolog 2 (MSH2). This study aimed to assess whether the mRNA expression of MLH1 in peripheral blood could be used as a biomarkers for the diagnosis of HNPCC. The mRNA level of MLH1 was determined in 19 HNPCC families (46 members) using real-time quantitative polymerase chain reaction (qPCR). The mRNA levels of MLH1 in HNPCC were significantly lower than controls (P MLH1 for the diagnosis of HNPCC with the area under curve of 0.858. At an optimal cut-off value (0.511), the mRNA level of MLH1 had a sensitivity of 81.3% and a specificity of 86.7% for distinguishing HNPCC from controls. In conclusion, the mRNA expression of MLH1 in peripheral blood may serve as a biomarker for the diagnosis of HNPCC.

  19. Deoxyinosine triphosphate induces MLH1/PMS2- and p53-dependent cell growth arrest and DNA instability in mammalian cells

    Science.gov (United States)

    Yoneshima, Yasuto; Abolhassani, Nona; Iyama, Teruaki; Sakumi, Kunihiko; Shiomi, Naoko; Mori, Masahiko; Shiomi, Tadahiro; Noda, Tetsuo; Tsuchimoto, Daisuke; Nakabeppu, Yusaku

    2016-01-01

    Deoxyinosine (dI) occurs in DNA either by oxidative deamination of a previously incorporated deoxyadenosine residue or by misincorporation of deoxyinosine triphosphate (dITP) from the nucleotide pool during replication. To exclude dITP from the pool, mammals possess specific hydrolysing enzymes, such as inosine triphosphatase (ITPA). Previous studies have shown that deficiency in ITPA results in cell growth suppression and DNA instability. To explore the mechanisms of these phenotypes, we analysed ITPA-deficient human and mouse cells. We found that both growth suppression and accumulation of single-strand breaks in nuclear DNA of ITPA-deficient cells depended on MLH1/PMS2. The cell growth suppression of ITPA-deficient cells also depended on p53, but not on MPG, ENDOV or MSH2. ITPA deficiency significantly increased the levels of p53 protein and p21 mRNA/protein, a well-known target of p53, in an MLH1-dependent manner. Furthermore, MLH1 may also contribute to cell growth arrest by increasing the basal level of p53 activity. PMID:27618981

  20. Age-Dependent Cancer Risk Is not Different in between MSH2 and MLH1 Mutation Carriers

    International Nuclear Information System (INIS)

    Olschwang, S.; Olschwang, S.; Yu, K.

    2009-01-01

    Lynch syndrome is mostly characterized by early-onset colorectal and endometrial adenocarcinomas. Over 90% of the causal mutations occur in two mismatch repair genes, MSH2 and MLH1. The aim of this study was to evaluate the age-dependent cancer risk in MSH2 or MLH1 mutation carriers from data of DNA diagnostic laboratories. To avoid overestimation, evaluation was based on the age-dependent proportion of mutation carriers in asymptomatic first-degree relatives of identified mutation carriers. Data from 859 such eligible relatives were collected from 8 centers; 387 were found to have inherited the mutation from their relatives. Age-dependent risks were calculated either using a nonparametric approach for four discrete age groups or assuming a modified Weibull distribution for the dependence of risk on age. Cancer risk was estimated starting at 28 (25-32 0.68 confidence interval) and to reach near 0.70 at 70 years. The risks were very similar for MSH2 and MLH1 mutation carriers. Although not statistically significant, the risk in males appeared to precede that for females by ten years. This difference needs to be investigated on a larger dataset. If confirmed, this would indicate that the onset of the colonoscopic surveillance may be different in male and female mutation carriers.

  1. Mlh1-Mlh3, a Meiotic Crossover and DNA Mismatch Repair Factor, Is a Msh2-Msh3-stimulated Endonuclease*

    Science.gov (United States)

    Rogacheva, Maria V.; Manhart, Carol M.; Chen, Cheng; Guarne, Alba; Surtees, Jennifer; Alani, Eric

    2014-01-01

    Crossing over between homologous chromosomes is initiated in meiotic prophase in most sexually reproducing organisms by the appearance of programmed double strand breaks throughout the genome. In Saccharomyces cerevisiae the double-strand breaks are resected to form three prime single-strand tails that primarily invade complementary sequences in unbroken homologs. These invasion intermediates are converted into double Holliday junctions and then resolved into crossovers that facilitate homolog segregation during Meiosis I. Work in yeast suggests that Msh4-Msh5 stabilizes invasion intermediates and double Holliday junctions, which are resolved into crossovers in steps requiring Sgs1 helicase, Exo1, and a putative endonuclease activity encoded by the DNA mismatch repair factor Mlh1-Mlh3. We purified Mlh1-Mlh3 and showed that it is a metal-dependent and Msh2-Msh3-stimulated endonuclease that makes single-strand breaks in supercoiled DNA. These observations support a direct role for an Mlh1-Mlh3 endonuclease activity in resolving recombination intermediates and in DNA mismatch repair. PMID:24403070

  2. DNA mismatch repair proteins MLH1 and PMS2 can be imported to the nucleus by a classical nuclear import pathway.

    Science.gov (United States)

    de Barros, Andrea C; Takeda, Agnes A S; Dreyer, Thiago R; Velazquez-Campoy, Adrian; Kobe, Boštjan; Fontes, Marcos R M

    2018-03-01

    MLH1 and PMS2 proteins form the MutLα heterodimer, which plays a major role in DNA mismatch repair (MMR) in humans. Mutations in MMR-related proteins are associated with cancer, especially with colon cancer. The N-terminal region of MutLα comprises the N-termini of PMS2 and MLH1 and, similarly, the C-terminal region of MutLα is composed by the C-termini of PMS2 and MLH1, and the two are connected by linker region. The nuclear localization sequences (NLSs) necessary for the nuclear transport of the two proteins are found in this linker region. However, the exact NLS sequences have been controversial, with different sequences reported, particularly for MLH1. The individual components are not imported efficiently, presumably due to their C-termini masking their NLSs. In order to gain insights into the nuclear transport of these proteins, we solved the crystal structures of importin-α bound to peptides corresponding to the supposed NLSs of MLH1 and PMS2 and performed isothermal titration calorimetry to study their binding affinities. Both putative MLH1 and PMS2 NLSs can bind to importin-α as monopartite NLSs, which is in agreement with some previous studies. However, MLH1-NLS has the highest affinity measured by a natural NLS peptide, suggesting a major role of MLH1 protein in nuclear import compared to PMS2. Finally, the role of MLH1 and PMS2 in the nuclear transport of the MutLα heterodimer is discussed. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  3. Germline MLH1 Mutations Are Frequently Identified in Lynch Syndrome Patients With Colorectal and Endometrial Carcinoma Demonstrating Isolated Loss of PMS2 Immunohistochemical Expression.

    Science.gov (United States)

    Dudley, Beth; Brand, Randall E; Thull, Darcy; Bahary, Nathan; Nikiforova, Marina N; Pai, Reetesh K

    2015-08-01

    Current guidelines on germline mutation testing for patients suspected of having Lynch syndrome are not entirely clear in patients with tumors demonstrating isolated loss of PMS2 immunohistochemical expression. We analyzed the clinical and pathologic features of patients with tumors demonstrating isolated loss of PMS2 expression in an attempt to (1) determine the frequency of germline MLH1 and PMS2 mutations and (2) correlate mismatch-repair protein immunohistochemistry and tumor histology with germline mutation results. A total of 3213 consecutive colorectal carcinomas and 215 consecutive endometrial carcinomas were prospectively analyzed for DNA mismatch-repair protein expression by immunohistochemistry. In total, 32 tumors from 31 patients demonstrated isolated loss of PMS2 immunohistochemical expression, including 16 colorectal carcinomas and 16 endometrial carcinomas. Microsatellite instability (MSI) polymerase chain reaction was performed in 29 tumors from 28 patients with the following results: 28 tumors demonstrated high-level MSI, and 1 tumor demonstrated low-level MSI. Twenty of 31 (65%) patients in the study group had tumors demonstrating histopathology associated with high-level MSI. Seventeen patients underwent germline mutation analysis with the following results: 24% with MLH1 mutations, 35% with PMS2 mutations, 12% with PMS2 variants of undetermined significance, and 29% with no mutations in either MLH1 or PMS2. Three of the 4 patients with MLH1 germline mutations had a mutation that results in decreased stability and quantity of the MLH1 protein that compromises the MLH1-PMS2 protein complex, helping to explain the presence of immunogenic but functionally inactive MLH1 protein within the tumor. The high frequency of MLH1 germline mutations identified in our study has important implications for testing strategies in patients suspected of having Lynch syndrome and indicates that patients with tumors demonstrating isolated loss of PMS2 expression

  4. Expression of the DNA repair gene MLH1 correlates with survival in patients who have resected pancreatic cancer and have received adjuvant chemoradiation: NRG Oncology RTOG Study 9704.

    Science.gov (United States)

    Lawrence, Yaacov R; Moughan, Jennifer; Magliocco, Anthony M; Klimowicz, Alexander C; Regine, William F; Mowat, Rex B; DiPetrillo, Thomas A; Small, William; Simko, Jeffry P; Golan, Talia; Winter, Kathryn A; Guha, Chandan; Crane, Christopher H; Dicker, Adam P

    2018-02-01

    The majority of patients with pancreatic cancer who undergo curative resection experience rapid disease recurrence. In previous small studies, high expression of the mismatch-repair protein mutL protein homolog 1 (MLH1) in pancreatic cancers was associated with better outcomes. The objective of this study was to validate the association between MLH1 expression and survival in patients who underwent resection of pancreatic cancer and received adjuvant chemoradiation. Samples were obtained from the NRG Oncology Radiation Therapy Oncology Group 9704 prospective, randomized trial (clinicaltrials.gov identifier NCT00003216), which compared 2 adjuvant protocols in patients with pancreatic cancer who underwent resection. Tissue microarrays were prepared from formalin-fixed, paraffin-embedded, resected tumor tissues. MLH1 expression was quantified using fluorescence immunohistochemistry and automated quantitative analysis, and expression was dichotomized above and below the median value. Immunohistochemical staining was successfully performed on 117 patients for MLH1 (60 and 57 patients from the 2 arms). The characteristics of the participants who had tissue samples available were similar to those of the trial population as a whole. At the time of analysis, 84% of participants had died, with a median survival of 17 months. Elevated MLH1 expression levels in tumor nuclei were significantly correlated with longer disease-free and overall survival in each arm individually and in both arms combined. Two-year overall survival was 16% in patients who had low MLH1 expression levels and 53% in those who had high MLH1 expression levels (P MLH1 expression was correlated with long-term survival. Further studies should assess whether MLH1 expression predicts which patients with localized pancreatic cancer may benefit most from aggressive, multimodality treatment. Cancer 2018;124:491-8. © 2017 American Cancer Society. © 2017 American Cancer Society.

  5. CpG Island Methylator Phenotype Positive Tumors in the Absence of MLH1 Methylation Constitute a Distinct Subset of Duodenal Adenocarcinomas and Are Associated with Poor Prognosis

    Science.gov (United States)

    Fu, Tao; Pappou, Emmanouil P.; Guzzetta, Angela A.; Jeschke, Jana; Kwak, Ruby; Dave, Pujan; Hooker, Craig M.; Morgan, Richard; Baylin, Stephen B.; Iacobuzio-Donahue, Christine A.; Wolfgang, Christopher L.; Ahuja, Nita

    2012-01-01

    Purpose Little information is available on genetic and epigenetic changes in duodenal adenocarcinomas. The purpose was to identify possible subsets of duodenal adenocarcinomas based on microsatellite instability (MSI), DNA methylation, mutations in the KRAS and BRAF genes, clinicopathologic features, and prognosis. Experimental Design Demographics, tumor characteristics and survival were available for 99 duodenal adenocarcinoma patients. Testing for KRAS and BRAF mutations, MSI, MLH1 methylation and CpG island methylator phenotype (CIMP) status was performed. A Cox proportional hazard model was built to predict survival. Results CIMP+ was detected in 27 of 99 (27.3%) duodenal adenocarcinomas, and was associated with MSI (P = 0.011) and MLH1 methylation (P CIMP− tumors. No BRAF V600E mutation was detected. Among the CIMP+ tumors, 15 (55.6%) were CIMP+/MLH1-unmethylated (MLH1-U). Kaplan-Meier analysis showed tumors classified by CIMP, CIMP/MLH1 methylation status or CIMP/MSI status could predict overall survival (OS; P = 0.047, 0.002, and 0.002, respectively), while CIMP/MLH1 methylation status could also predict time-to-recurrence (TTR; P = 0.016). In multivariate analysis, CIMP/MLH1 methylation status showed a significant prognostic value regarding both OS (P CIMP+/MLH1-U tumors had the worst OS and TTR. Conclusions Our results demonstrate existence of CIMP in duodenal adenocarcinomas. The combination of CIMP+/MLH1-U appears to be independently associated with poor prognosis in patients with duodenal adenocarcinomas. This study also suggests that BRAF mutations are not involved in duodenal tumorigenesis, MSI or CIMP development. PMID:22825585

  6. Quantitative PCR high-resolution melting (qPCR-HRM) curve analysis, a new approach to simultaneously screen point mutations and large rearrangements: application to MLH1 germline mutations in Lynch syndrome.

    Science.gov (United States)

    Rouleau, Etienne; Lefol, Cédrick; Bourdon, Violaine; Coulet, Florence; Noguchi, Tetsuro; Soubrier, Florent; Bièche, Ivan; Olschwang, Sylviane; Sobol, Hagay; Lidereau, Rosette

    2009-06-01

    Several techniques have been developed to screen mismatch repair (MMR) genes for deleterious mutations. Until now, two different techniques were required to screen for both point mutations and large rearrangements. For the first time, we propose a new approach, called "quantitative PCR (qPCR) high-resolution melting (HRM) curve analysis (qPCR-HRM)," which combines qPCR and HRM to obtain a rapid and cost-effective method suitable for testing a large series of samples. We designed PCR amplicons to scan the MLH1 gene using qPCR HRM. Seventy-six patients were fully scanned in replicate, including 14 wild-type patients and 62 patients with known mutations (57 point mutations and five rearrangements). To validate the detected mutations, we used sequencing and/or hybridization on a dedicated MLH1 array-comparative genomic hybridization (array-CGH). All point mutations and rearrangements detected by denaturing high-performance liquid chromatography (dHPLC)+multiplex ligation-dependent probe amplification (MLPA) were successfully detected by qPCR HRM. Three large rearrangements were characterized with the dedicated MLH1 array-CGH. One variant was detected with qPCR HRM in a wild-type patient and was located within the reverse primer. One variant was not detected with qPCR HRM or with dHPLC due to its proximity to a T-stretch. With qPCR HRM, prescreening for point mutations and large rearrangements are performed in one tube and in one step with a single machine, without the need for any automated sequencer in the prescreening process. In replicate, its reagent cost, sensitivity, and specificity are comparable to those of dHPLC+MLPA techniques. However, qPCR HRM outperformed the other techniques in terms of its rapidity and amount of data provided.

  7. Transactivation of the proximal promoter of human oxytocin gene by TR4 orphan receptor

    International Nuclear Information System (INIS)

    Wang, C.-P.; Lee, Y.-F.; Chang, C.; Lee, H.-J.

    2006-01-01

    The human testicular receptor 4 (TR4) shares structural homology with members of the nuclear receptor superfamily. Some other members of this superfamily were able to regulate the transcriptional activity of the human oxytocin (OXT) promoter by binding to the first DR0 regulatory site. However, little investigation was conducted systematically in the study of the second dDR4 site of OXT proximal promoter, and the relationship between the first and the second sites of OXT promoter. Here, we demonstrated for the first time that TR4 could increase the proximal promoter activity of the human OXT gene via DR0, dDR4, and OXT (both DR0 and dDR4) elements, respectively. TR4 might induce OXT gene expression through the OXT element in a dose-dependent manner. However, there is no synergistic effect between DR0 and dDR4 elements during TR4 transactivation. Taken together, these results suggested that TR4 should be one of important regulators of OXT gene expression

  8. The silent mutation MLH1 c.543C>T resulting in aberrant splicing can cause Lynch syndrome: a case report.

    Science.gov (United States)

    Yamaguchi, Tatsuro; Wakatsuki, Tomokazu; Kikuchi, Mari; Horiguchi, Shin-Ichiro; Akagi, Kiwamu

    2017-06-01

    The proband was a 67-year-old man with transverse and sigmoid colon cancer. Microsatellite instability analysis revealed a high frequency of microsatellite instability, and immunohistochemical staining showed the absence of both MLH1 and PMS2 proteins in the sigmoid colon cancer tissue specimens from the patient. DNA sequencing revealed a nucleotide substitution c.543C>T in MLH1, but this variant did not substitute an amino acid. The MLH1 c.543C>T variant was located 3 bases upstream from the end of exon 6 and created a new splice donor site 4 bases upstream from the end of exon 6. Consequently, the last 4 bases of exon 6 were deleted and frameshift occurred. Thus, the MLH1 c.543C>T silent mutation is considered 'pathogenic'. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Epitope-positive truncating MLH1 mutation and loss of PMS2: implications for IHC-directed genetic testing for Lynch syndrome.

    Science.gov (United States)

    Zighelboim, Israel; Powell, Matthew A; Babb, Sheri A; Whelan, Alison J; Schmidt, Amy P; Clendenning, Mark; Senter, Leigha; Thibodeau, Stephen N; de la Chapelle, Albert; Goodfellow, Paul J

    2009-01-01

    We assessed mismatch repair by immunohistochemistry (IHC) and microsatellite instability (MSI) analysis in an early onset endometrial cancer and a sister's colon cancer. We demonstrated high-level MSI and normal expression for MLH1, MSH2 and MSH6. PMS2 failed to stain in both tumors, strongly implicating a PMS2 defect. This family did not meet clinical criteria for Lynch syndrome. However, early onset endometrial cancers in the proband and her sister, a metachronous colorectal cancer in the sister as well as MSI in endometrial and colonic tumors suggested a heritable mismatch repair defect. PCR-based direct exonic sequencing and multiplex ligation-dependent probe amplification (MLPA) were undertaken to search for PMS2 mutations in the germline DNA from the proband and her sister. No mutation was identified in the PMS2 gene. However, PMS2 exons 3, 4, 13, 14, 15 were not evaluated by MLPA and as such, rearrangements involving those exons cannot be excluded. Clinical testing for MLH1 and MSH2 mutation revealed a germline deletion of MLH1 exons 14 and 15. This MLH1 germline deletion leads to an immunodetectable stable C-terminal truncated MLH1 protein which based on the IHC staining must abrogate PMS2 stabilization. To the best of our knowledge, loss of PMS2 in MLH1 truncating mutation carriers that express MLH1 in their tumors has not been previously reported. This family points to a potential limitation of IHC-directed gene testing for suspected Lynch syndrome and the need to consider comprehensive MLH1 testing for individuals whose tumors lack PMS2 but for whom PMS2 mutations are not identified.

  10. Mlh1 is required for female fertility in Drosophila melanogaster: An outcome of effects on meiotic crossing over, ovarian follicles and egg activation.

    Science.gov (United States)

    Vimal, Divya; Kumar, Saurabh; Pandey, Ashutosh; Sharma, Divya; Saini, Sanjay; Gupta, Snigdha; Ravi Ram, Kristipati; Chowdhuri, Debapratim Kar

    2018-03-01

    Mismatch repair (MMR) system, a conserved DNA repair pathway, plays crucial role in DNA recombination and is involved in gametogenesis. The impact of alterations in MMR family of proteins (bacterial MutS and MutL homologues) on mammalian fertility is well documented. However, an insight to the role of MMR in reproduction of non-mammalian organisms is limited. Hence, in the present study, we analysed the impact of mlh1 (a MutL homologue) on meiotic crossing over/recombination and fertility in a genetically tractable model, Drosophila melanogaster. Using mlh1 e00130 hypomorphic allele, we report female specific adverse reproductive outcome for reduced mlh1 in Drosophila: mlh1 e00130 homozygous females had severely reduced fertility while males were fertile. Further, mlh1 e00130 females contained small ovaries with large number of early stages as well as significantly reduced mature oocytes, and laid fewer eggs, indicating discrepancies in egg production and ovulation. These observations contrast the sex independent and/or male specific sterility and normal follicular development as well as ovulation reported so far for MMR family proteins in mammals. However, analogous to the role(s) of mlh1 in meiotic crossing over and DNA repair processes underlying mammalian fertility, ovarian follicles from mlh1 e00130 females contained significantly increased DNA double strand breaks (DSBs) and reduced synaptonemal complex foci. In addition, large proportion of fertilized eggs display discrepancies in egg activation and fail to proceed beyond stage 5 of embryogenesis. Hence, reduction of the Mlh1 protein level leads to defective oocytes that fail to complete embryogenesis after fertilization thereby reducing female fertility. Copyright © 2017 Elsevier GmbH. All rights reserved.

  11. MLH1 V384D polymorphism associates with poor response to EGFR tyrosine kinase inhibitors in patients with EGFR L858R-positive lung adenocarcinoma.

    Science.gov (United States)

    Chiu, Chao-Hua; Ho, Hsiang-Ling; Doong, Howard; Yeh, Yi-Chen; Chen, Mei-Yu; Chou, Teh-Ying; Tsai, Chun-Ming

    2015-04-10

    A significant fraction of patients with lung adenocarcinomas harboring activating epidermal growth factor receptor (EGFR) mutations do not experience clinical benefits from EGFR tyrosine kinase inhibitor (TKI) therapy. Using next-generation sequencing, we screened 739 mutation hotspots in 46 cancer-related genes in EGFR L858R-mutant lung adenocarcinomas from 29 patients who received EGFR-TKI therapy; 13 had short ( 1 year) progression-free survival (PFS). We discovered MLH1 V384D as a genetic variant enriched in the group of patients with short PFS. Next, we investigated this genetic variation in 158 lung adenocarcinomas with the EGFR L858R mutation and found 14 (8.9%) patients had MLH1 V384D; available blood or non-tumor tissues from patients were also tested positive for MLH1 V384D. Patients with MLH1 V384D had a significantly shorter median PFS than those without (5.1 vs. 10.6 months; P= 0.001). Multivariate analysis showed that MLH1 V384D polymorphism was an independent predictor for a reduced PFS time (hazard ratio, 3.5; 95% confidence interval, 1.7 to 7.2; P= 0.001). In conclusion, MLH1 V384D polymorphism is associated with primary resistance to EGFR-TKIs in patients with EGFR L858R-positive lung adenocarcinoma and may potentially be a novel biomarker to guide treatment decisions.

  12. Genetic variation in the proximal promoter of ABC and SLC superfamilies: liver and kidney specific expression and promoter activity predict variation.

    Directory of Open Access Journals (Sweden)

    Stephanie E Hesselson

    2009-09-01

    Full Text Available Membrane transporters play crucial roles in the cellular uptake and efflux of an array of small molecules including nutrients, environmental toxins, and many clinically used drugs. We hypothesized that common genetic variation in the proximal promoter regions of transporter genes contribute to observed variation in drug response. A total of 579 polymorphisms were identified in the proximal promoters (-250 to +50 bp and flanking 5' sequence of 107 transporters in the ATP Binding Cassette (ABC and Solute Carrier (SLC superfamilies in 272 DNA samples from ethnically diverse populations. Many transporter promoters contained multiple common polymorphisms. Using a sliding window analysis, we observed that, on average, nucleotide diversity (pi was lowest at approximately 300 bp upstream of the transcription start site, suggesting that this region may harbor important functional elements. The proximal promoters of transporters that were highly expressed in the liver had greater nucleotide diversity than those that were highly expressed in the kidney consistent with greater negative selective pressure on the promoters of kidney transporters. Twenty-one promoters were evaluated for activity using reporter assays. Greater nucleotide diversity was observed in promoters with strong activity compared to promoters with weak activity, suggesting that weak promoters are under more negative selective pressure than promoters with high activity. Collectively, these results suggest that the proximal promoter region of membrane transporters is rich in variation and that variants in these regions may play a role in interindividual variation in drug disposition and response.

  13. The mismatch repair and meiotic recombination endonuclease Mlh1-Mlh3 is activated by polymer formation and can cleave DNA substrates in trans.

    Science.gov (United States)

    Manhart, Carol M; Ni, Xiaodan; White, Martin A; Ortega, Joaquin; Surtees, Jennifer A; Alani, Eric

    2017-04-01

    Crossing over between homologs is initiated in meiotic prophase by the formation of DNA double-strand breaks that occur throughout the genome. In the major interference-responsive crossover pathway in baker's yeast, these breaks are resected to form 3' single-strand tails that participate in a homology search, ultimately forming double Holliday junctions (dHJs) that primarily include both homologs. These dHJs are resolved by endonuclease activity to form exclusively crossovers, which are critical for proper homolog segregation in Meiosis I. Recent genetic, biochemical, and molecular studies in yeast are consistent with the hypothesis of Mlh1-Mlh3 DNA mismatch repair complex acting as the major endonuclease activity that resolves dHJs into crossovers. However, the mechanism by which the Mlh1-Mlh3 endonuclease is activated is unknown. Here, we provide evidence that Mlh1-Mlh3 does not behave like a structure-specific endonuclease but forms polymers required to generate nicks in DNA. This conclusion is supported by DNA binding studies performed with different-sized substrates that contain or lack polymerization barriers and endonuclease assays performed with varying ratios of endonuclease-deficient and endonuclease-proficient Mlh1-Mlh3. In addition, Mlh1-Mlh3 can generate religatable double-strand breaks and form an active nucleoprotein complex that can nick DNA substrates in trans. Together these observations argue that Mlh1-Mlh3 may not act like a canonical, RuvC-like Holliday junction resolvase and support a novel model in which Mlh1-Mlh3 is loaded onto DNA to form an activated polymer that cleaves DNA.

  14. IMMUNOHISTOCHEMICAL STUDY OF MSH2, MSH6, PMS2, MLH1 IN EVALUATION OF DIFFERENTIATION GRADE OF COLON ADENOCARCINOMA

    Directory of Open Access Journals (Sweden)

    G. A. Raskin

    2015-01-01

    Full Text Available Microsatellite instability is associated with dysfunction of the MSH2, MLH1, PMS2 and MSH6 genes, which participate in the repair of unpaired nucleotides of DNA. It is known that microsatellite instability is an independent prognostic factor in determining the differentiation grade of colon cancer. The use of immunohistochemistry to study the repair system of unpaired nucleotides has its own characteristics and limitations. Materials and methods. The study included 39 patients with colon adenocarcinoma. Moderately-differentiated colon adenocarcinoma was the most common histological type (72 %. There were 8 % of well-differentiated and 12 % poorly-differentiated carcinomas. Immunohistochemical analysis of SH2, MSH6, PMS2 and MLH1 proteins was done according to the standard protocol. Results. Out of 39 cases, 6 (15 % had loss of expression of at least one of the studied proteins. Out of these 6 cases with indirect signs of MSI-H, 3 were poorlydifferentiated, 1 was mucinous and 2 were moderately differentiated adenocarcinomas. Conclusion. Thus, immunohistochemical analysis of DNA repair genes can be used to determine the histological differentiation of colon adenocarcinoma.

  15. A novel deletion in the splice donor site of MLH1 exon 6 in a Japanese colon cancer patient with Lynch syndrome.

    Science.gov (United States)

    Yamaguchi, Junya; Sato, Yuri; Kita, Mizuho; Nomura, Sachio; Yamamoto, Noriko; Kato, Yo; Ishikawa, Yuichi; Arai, Masami

    2015-10-01

    Lynch syndrome is an autosomal dominantly inherited disease that is characterized by a predisposition to cancers, mainly colorectal cancer. Germline mutations of DNA mismatch repair genes such as MLH1, MSH2, MSH6 and PMS2 have been described in patients with Lynch syndrome. Here, we report deletion of 2 bp in the splice donor site of the MLH1 exon 6 (c.545+4_545+5delCA) in a 48-year-old Japanese woman with Lynch syndrome. RT-PCR direct sequencing analysis revealed that this mutation led to an increase in the level of an MLH1 transcript in which exon 6 was skipped, and may cause a frameshift (p.E153FfsX8). Therefore, this mutation appears to be pathogenic and is responsible for Lynch syndrome. Additionally, analysis of the patient's tumor cells indicated microsatellite instability high phenotype and loss of the MLH1 and PMS2 proteins. To our knowledge, this is a germline splice site mutation of MLH1 that has not been reported previously. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Counteraction of Oxidative Stress by Vitamin E Affects Epigenetic Regulation by Increasing Global Methylation and Gene Expression of MLH1 and DNMT1 Dose Dependently in Caco-2 Cells

    Directory of Open Access Journals (Sweden)

    Katja Zappe

    2018-01-01

    Full Text Available Obesity- or diabetes-induced oxidative stress is discussed as a major risk factor for DNA damage. Vitamin E and many polyphenols exhibit antioxidative activities with consequences on epigenetic regulation of inflammation and DNA repair. The present study investigated the counteraction of oxidative stress by vitamin E in the colorectal cancer cell line Caco-2 under normal (1 g/l and high (4.5 g/l glucose cell culture condition. Malondialdehyde (MDA as a surrogate marker of lipid peroxidation and reactive oxygen species (ROS was analyzed. Gene expression and promoter methylation of the DNA repair gene MutL homolog 1 (MLH1 and the DNA methyltransferase 1 (DNMT1 as well as global methylation by LINE-1 were investigated. Results revealed a dose-dependent counteracting effect of vitamin E on H2O2-induced oxidative stress. Thereby, 10 μM vitamin E proved to be more efficient than did 50 μM in reducing MDA. Further, an induction of MLH1 and DNMT1 gene expression was noticed, accompanied by an increase in global methylation. Whether LINE-1 hypomethylation is a cause or effect of oxidative stress is still unclear. In conclusion, supplementation of exogenous antioxidants like vitamin E in vitro exhibits beneficial effects concerning oxidative stress as well as epigenetic regulation involved in DNA repair.

  17. AKT increases VEGF expression in tumor cells by transactivating the proximal VEGF promoter

    International Nuclear Information System (INIS)

    Pore, N.; Bernhard, E.J.; Shu, H.-K.; Li, B.; O'Rourke, D.M.; Maity, A.; Haas-Kogan, D.

    2003-01-01

    Vascular endothelial growth factor (VEGF) is overexpressed in many cancers including glioblastomas and may contribute to their growth. Epidermal growth factor receptor (EGFR) amplification and loss of PTEN, commonly found in glioblastomas leading to increase phosphatidylinositol-3-kinase (PI3K) activity and VEGF expression. In the current study we show that AKT, which is downstream of PI3K, regulates VEGF expression. U87MG human glioblastoma cells lack wildtype PTEN and express high levels of phosphorylated AKT. Over expression of AKT either by stable expression in immortalized human astrocytes or by transduction with adenovirus containing activated myristoylated AKT in SF188 glioblastoma cells increases VEGF expression. Moreover the elevation of angiogenesis by constitutively expressed AKT is further confirmed by in vivo matrigel plug assay in nude mice. The upregulation of VEGF by AKT is mediated through a region in the proximal promoter located between -88 and -70 (+1 is transcription start site). In transient transfection activity of a luciferase reporter containing the -88/+54 region of the VEGF promoter is increased by cotransfection with myristoylated AKT and downregulated by a dominant negative AKT expression vector. Mutation of the putative Sp1 binding sites located in the -88/-70 region we show that AKT acts through Sp1 to transactivate the VEGF promoter. Cotransfection of the VEGF promoter reporter with both Sp1 and myristoylated AKT expression vectors increases promoter activity to a greater extent than either Sp1 or Akt by itself. In vivo phosphate labeling of proteins reveals that AKT leads to increased Sp1 phosphorylation. Gel shift assays using a radio labeled probe corresponding to nucleotides -88 through -66 in the promoter show increased binding with nuclear extracts from cells transduced with adenovirus expressing myristoylated AKT. In conclusion, our results suggest that loss of PTEN leads to increased VEGF expression by increasing AKT

  18. Expression of DNA repair proteins MSH2, MLH1 and MGMT in human benign and malignant thyroid lesions: An immunohistochemical study

    Science.gov (United States)

    Giaginis, Constantinos; Michailidi, Christina; Stolakis, Vasileios; Alexandrou, Paraskevi; Tsourouflis, Gerasimos; Klijanienko, Jerzy; Delladetsima, Ioanna; Theocharis, Stamatios

    2011-01-01

    Summary Background DNA repair is a major defense mechanism, which contributes to the maintenance of genetic sequence, and minimizes cell death, mutation rates, replication errors, DNA damage persistence and genomic instability. Alterations in the expression levels of proteins participating in DNA repair mechanisms have been associated with several aspects of cancer biology. The present study aimed to evaluate the clinical significance of DNA repair proteins MSH2, MLH1 and MGMT in benign and malignant thyroid lesions. Material/Methods MSH2, MLH1 and MGMT protein expression was assessed immunohistochemically on paraffin-embedded thyroid tissues from 90 patients with benign and malignant lesions. Results The expression levels of MLH1 was significantly upregulated in cases with malignant compared to those with benign thyroid lesions (p=0.038). The expression levels of MGMT was significantly downregulated in malignant compared to benign thyroid lesions (p=0.001). Similar associations for both MLH1 and MGMT between cases with papillary carcinoma and hyperplastic nodules were also noted (p=0.014 and p=0.026, respectively). In the subgroup of malignant thyroid lesions, MSH2 downregulation was significantly associated with larger tumor size (p=0.031), while MLH1 upregulation was significantly associated with the presence of lymphatic and vascular invasion (p=0.006 and p=0.002, respectively). Conclusions Alterations in the mismatch repair proteins MSH2 and MLH1 and the direct repair protein MGMT may result from tumor development and/or progression. Further studies are recommended to draw definite conclusions on the clinical significance of DNA repair proteins in thyroid neoplasia. PMID:21358597

  19. Genotyping of BRCA1, BRCA2, p53, CDKN2A, MLH1 and MSH2 genes in a male patient with secondary breast cancer

    International Nuclear Information System (INIS)

    Vodusek, Ana Lina; Novakovic, Srdjan; Stegel, Vida; Jereb, Berta

    2011-01-01

    Some tumour suppressor genes (BRCA2) and mismatch repair genes (MSH2, MLH1) are correlated with an increased risk for male breast cancer. Our patient developed secondary breast cancer after the treatment for Hodgkin’s disease in childhood. DNA was isolated from the patients’ blood and screened for mutations, polymorphisms and variants in BRCA1, BRCA2, p53, CDKN2A, MLH1 and MSH2 genes. We found no mutations but common polymorphisms, and three variants in mismatch repair genes. Nucleotide variants c.2006-6T>C and p.G322D in MSH2 might be correlated with male breast cancer

  20. Four novel germline mutations in the MLH1 and PMS2 mismatch repair genes in patients with hereditary nonpolyposis colorectal cancer.

    Science.gov (United States)

    Montazer Haghighi, Mahdi; Radpour, Ramin; Aghajani, Katayoun; Zali, Narges; Molaei, Mahsa; Zali, Mohammad Reza

    2009-08-01

    Hereditary nonpolyposis colorectal cancer (HNPCC) is the most common cause of early onset hereditary colorectal cancer. In the majority of HNPCC families, microsatellite instability (MSI) and germline mutation in one of the DNA mismatch repair (MMR) genes are found. The entire coding sequence of MMR genes (MLH1, MLH2, MLH6, and PMS2) was analyzed using direct sequencing. Also, tumor tests were done as MSI and immunohistochemistry testing. We were able to find three novel MLH1 and one novel PMS2 germline mutations in three Iranian HNPCC patients. The first was a transversion mutation c.346A>C (T116P) and happened in the highly conserved HATPase-c region of MLH1 protein. The second was a transversion mutation c.736A>T (I246L), which caused an amino acid change of isoleucine to leucine. The third mutation (c.2145,6 delTG) was frameshift and resulted in an immature stop codon in five codons downstream. All of these three mutations were detected in the MLH1 gene. The other mutation was a transition mutation, c.676G>A (G207E), which has been found in exon six of the PMS2 gene and caused an amino acid change of glycine to glutamic acid. MSI assay revealed high instability in microsatellite for two patients and microsatellite stable for one patient. In all patients, an abnormal expression of the MMR proteins in HNPCC was related to the above novel mutations.

  1. Meat and fish consumption, APC gene mutations and hMLH1 expression in colon and rectal cancer: a prospective cohort study (the Netherlands)

    NARCIS (Netherlands)

    Luchtenborg, M.; Weijenberg, M.P.; Goeij, de A.F.P.M.; Wark, P.A.; Brink, M.; Roemen, G.M.J.M.; Lentjes, M.H.F.M.; Bruine, de A.P.; Goldbohm, R.A.; Veer, van 't P.; Brandt, van den P.A.

    2005-01-01

    Objective:The aim of this study was to investigate the associations between meat and fish consumption and APC mutation status and hMLH1 expression in colon and rectal cancer. Methods:The associations were investigated in the Netherlands Cohort Study, and included 434 colon and 154 rectal cancer

  2. Detection and precise mapping of germline rearrangements in BRCA1, BRCA2, MSH2, and MLH1 using zoom-in array comparative genomic hybridization (aCGH)

    DEFF Research Database (Denmark)

    Staaf, Johan; Törngren, Therese; Rambech, Eva

    2008-01-01

    deletions or duplications occurring in BRCA1 (n=11), BRCA2 (n=2), MSH2 (n=7), or MLH1 (n=9). Additionally, we demonstrate its applicability for uncovering complex somatic rearrangements, exemplified by zoom-in analysis of the PTEN and CDKN2A loci in breast cancer cells. The sizes of rearrangements ranged...

  3. RRAF-V600E is not involved in the colorectal tumorigenesis of HNPCC in patients with functional MLH1 and MSH2 genes

    NARCIS (Netherlands)

    Domingo, E; Niessen, RC; Oliveira, C; Alhopuro, P; Moutinho, C; Espin, E; Armengol, M; Sijmons, RH; Kleibeuker, JH; Seruca, R; Aaltonen, LA; Imai, K; Yamamoto, H; Schwartz, S; Hofstra, RMW

    2005-01-01

    Recently, it was shown that the oncogenic activation of BRAF, a member of the RAS/RAF family of kinases, by the V600E mutation is characteristic for sporadic colon tumors with microsatellite instability. Further, it was shown to associate with the silencing of the mismatch repair (MMR) gene MLH1 by

  4. MSH2 mutation carriers are at higher risk of cancer than MLH1 mutation carriers : A study of hereditary nonpolyposis colorectal cancer families

    NARCIS (Netherlands)

    Vasen, HFA; Stormorken, A; Menko, FH; Nagengast, FM; Kleibeuker, JH; Griffioen, G; Taal, BG; Moller, P; Wijnen, JT

    2001-01-01

    Purpose: Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant disease characterized by the clustering of colorectal cancer, endometrial cancer, and various other cancers. The disease is caused by mutations in DNA-mismatch-repair (MMR) genes, most frequently in MLH1, MSH2, and

  5. Phenotype comparison of MLH1 and MSH2 mutation carriers in a cohort of 1,914 individuals undergoing clinical genetic testing in the United States

    NARCIS (Netherlands)

    F. Kastrinos (Fay); E.M. Stoffel (Elena); J. Balmana (Judith); E.W. Steyerberg (Ewout); R. Mercado (Rowena); S. Syngal (Sapna)

    2008-01-01

    textabstractBackground and Aims: Lynch syndrome is caused by germ-line mismatch repair gene mutations. We examined the phenotypic differences between MLH1 and MSH2 gene mutation carriers and whether mutation type (point versus large rearrangement) affected phenotypic expression. Methods: This is a

  6. MSH2 mutation carriers are at higher risk of cancer than MLH1 mutation carriers: a study of hereditary nonpolyposis colorectal cancer families.

    NARCIS (Netherlands)

    Vasen, H.F.; Stormorken, A.; Menko, F.H.; Nagengast, F.M.; Kleibeuker, J.H.; Griffioen, G.; Taal, B.G.; Moller, P.; Wijnen, J.T.

    2001-01-01

    PURPOSE: Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant disease characterized by the clustering of colorectal cancer, endometrial cancer, and various other cancers. The disease is caused by mutations in DNA-mismatch-repair (MMR) genes, most frequently in MLH1, MSH2, and

  7. Rapidly progressive adenomatous polyposis in a patient with germline mutations in both the APC and MLH1 genes: the worst of two worlds.

    NARCIS (Netherlands)

    Scheenstra, R; Rijcken, FE; Koornstra, JJ; Hollema, H; Fodde, R; Menko, F.H.; Sijmons, RH; Bijleveld, CM; Kleibeuker, J.H.

    2003-01-01

    The two most common inherited forms of colorectal cancer are familial adenomatous polyposis and hereditary non-polyposis colorectal cancer. Simultaneous inheritance of both an APC gene mutation and a mismatch repair gene (for example, MLH1) mutation has never been described. In the present case

  8. Germline MLH1, MSH2 and MSH6 variants in Brazilian patients with colorectal cancer and clinical features suggestive of Lynch Syndrome.

    Science.gov (United States)

    Schneider, Nayê Balzan; Pastor, Tatiane; Paula, André Escremim de; Achatz, Maria Isabel; Santos, Ândrea Ribeiro Dos; Vianna, Fernanda Sales Luiz; Rosset, Clévia; Pinheiro, Manuela; Ashton-Prolla, Patricia; Moreira, Miguel Ângelo Martins; Palmero, Edenir Inêz

    2018-05-01

    Lynch syndrome (LS) is the most common hereditary colorectal cancer syndrome, caused by germline mutations in one of the major genes involved in mismatch repair (MMR): MLH1, MSH2, MSH6 and more rarely, PMS2. Recently, germline deletions in EPCAM have been also associated to the syndrome. Most of the pathogenic MMR mutations found in LS families occur in MLH1 or MSH2. Gene variants include missense, nonsense, frameshift mutations, large genomic rearrangements and splice-site variants and most of the studies reporting the molecular characterization of LS families have been conducted outside South America. In this study, we analyzed 60 unrelated probands diagnosed with colorectal cancer and LS criteria. Testing for germline mutations and/or rearrangements in the most commonly affected MMR genes (MLH1, MSH2, EPCAM and MSH6) was done by Sanger sequencing and MLPA. Pathogenic or likely pathogenic variants were identified in MLH1 or MSH2 in 21 probands (35.0%). Of these, approximately one-third were gene rearrangements. In addition, nine variants of uncertain significance (VUS) were identified in 10 (16.6%) of the sixty probands analyzed. Other four novel variants were identified, only in MLH1. Our results suggest that MSH6 pathogenic variants are not common among Brazilian LS probands diagnosed with CRC and that MMR gene rearrangements account for a significant proportion of the germline variants in this population underscoring the need to include rearrangement analysis in the molecular testing of Brazilian individuals with suspected Lynch syndrome. © 2018 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

  9. Far infrared radiation promotes rabbit renal proximal tubule cell proliferation and functional characteristics, and protects against cisplatin-induced nephrotoxicity.

    Science.gov (United States)

    Chiang, I-Ni; Pu, Yeong-Shiau; Huang, Chao-Yuan; Young, Tai-Horng

    2017-01-01

    Far infrared radiation, a subdivision of the electromagnetic spectrum, is beneficial for long-term tissue healing, anti-inflammatory effects, growth promotion, sleep modulation, acceleration of microcirculation, and pain relief. We investigated if far infrared radiation is beneficial for renal proximal tubule cell cultivation and renal tissue engineering. We observed the effects of far infrared radiation on renal proximal tubules cells, including its effects on cell proliferation, gene and protein expression, and viability. We also examined the protective effects of far infrared radiation against cisplatin, a nephrotoxic agent, using the human proximal tubule cell line HK-2. We found that daily exposure to far infrared radiation for 30 min significantly increased rabbit renal proximal tubule cell proliferation in vitro, as assessed by MTT assay. Far infrared radiation was not only beneficial to renal proximal tubule cell proliferation, it also increased the expression of ATPase Na+/K+ subunit alpha 1 and glucose transporter 1, as determined by western blotting. Using quantitative polymerase chain reaction, we found that far infrared radiation enhanced CDK5R1, GNAS, NPPB, and TEK expression. In the proximal tubule cell line HK-2, far infrared radiation protected against cisplatin-mediated nephrotoxicity by reducing apoptosis. Renal proximal tubule cell cultivation with far infrared radiation exposure resulted in better cell proliferation, significantly higher ATPase Na+/K+ subunit alpha 1 and glucose transporter 1 expression, and significantly enhanced expression of CDK5R1, GNAS, NPPB, and TEK. These results suggest that far infrared radiation improves cell proliferation and differentiation. In HK-2 cells, far infrared radiation mediated protective effects against cisplatin-induced nephrotoxicity by reducing apoptosis, as indicated by flow cytometry and caspase-3 assay.

  10. The enrichment of TATA box and the scarcity of depleted proximal nucleosome in the promoters of duplicated yeast genes.

    Science.gov (United States)

    Kim, Yuseob; Lee, Jang H; Babbitt, Gregory A

    2010-01-01

    Population genetic theory of gene duplication suggests that the preservation of duplicate copies requires functional divergence upon duplication. Genes that can be readily modified to produce new gene expression patterns may thus be duplicated often. In yeast, genes exhibit dichotomous expression patterns based on their promoter architectures. The expression of genes that contain TATA box or occupied proximal nucleosome (OPN) tends to be variable and respond to external signals. On the other hand, genes without TATA box or with depleted proximal nucleosome (DPN) are expressed constitutively. We find that recent duplicates in the yeast genome are heavily biased to be TATA box containing genes and not to be DPN genes. This suggests that variably expressed genes, due to the functional organization in their promoters, have higher duplicability than constitutively expressed genes.

  11. Epigenetic silencing of MLH1 in endometrial cancers is associated with larger tumor volume, increased rate of lymph node positivity and reduced recurrence-free survival.

    Science.gov (United States)

    Cosgrove, Casey M; Cohn, David E; Hampel, Heather; Frankel, Wendy L; Jones, Dan; McElroy, Joseph P; Suarez, Adrian A; Zhao, Weiqiang; Chen, Wei; Salani, Ritu; Copeland, Larry J; O'Malley, David M; Fowler, Jeffrey M; Yilmaz, Ahmet; Chassen, Alexis S; Pearlman, Rachel; Goodfellow, Paul J; Backes, Floor J

    2017-09-01

    To determine the relationship between mismatch repair (MMR) classification and clinicopathologic features including tumor volume, and explore outcomes by MMR class in a contemporary cohort. Single institution cohort evaluating MMR classification for endometrial cancers (EC). MMR immunohistochemistry (IHC)±microsatellite instability (MSI) testing and reflex MLH1 methylation testing was performed. Tumors with MMR abnormalities by IHC or MSI and MLH1 methylation were classified as epigenetic MMR deficiency while those without MLH1 methylation were classified as probable MMR mutations. Clinicopathologic characteristics were analyzed. 466 endometrial cancers were classified; 75% as MMR proficient, 20% epigenetic MMR defects, and 5% as probable MMR mutations. Epigenetic MMR defects were associated with advanced stage, higher grade, presence of lymphovascular space invasion, and older age. MMR class was significantly associated with tumor volume, an association not previously reported. The epigenetic MMR defect tumors median volume was 10,220mm 3 compared to 3321mm 3 and 2,846mm 3 , for MMR proficient and probable MMR mutations respectively (PMLH1 methylation analysis defines a subset of tumors that have worse prognostic features and reduced RFS. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Colorectal cancer incidence in path_MLH1 carriers subjected to different follow-up protocols: a Prospective Lynch Syndrome Database report.

    Science.gov (United States)

    Seppälä, Toni; Pylvänäinen, Kirsi; Evans, Dafydd Gareth; Järvinen, Heikki; Renkonen-Sinisalo, Laura; Bernstein, Inge; Holinski-Feder, Elke; Sala, Paola; Lindblom, Annika; Macrae, Finlay; Blanco, Ignacio; Sijmons, Rolf; Jeffries, Jacqueline; Vasen, Hans; Burn, John; Nakken, Sigve; Hovig, Eivind; Rødland, Einar Andreas; Tharmaratnam, Kukatharmini; de Vos Tot Nederveen Cappel, Wouter H; Hill, James; Wijnen, Juul; Jenkins, Mark; Genuardi, Maurizio; Green, Kate; Lalloo, Fiona; Sunde, Lone; Mints, Miriam; Bertario, Lucio; Pineda, Marta; Navarro, Matilde; Morak, Monika; Frayling, Ian M; Plazzer, John-Paul; Sampson, Julian R; Capella, Gabriel; Möslein, Gabriela; Mecklin, Jukka-Pekka; Møller, Pål

    2017-01-01

    We have previously reported a high incidence of colorectal cancer (CRC) in carriers of pathogenic MLH1 variants (path_MLH1 ) despite follow-up with colonoscopy including polypectomy. The cohort included Finnish carriers enrolled in 3-yearly colonoscopy ( n  = 505; 4625 observation years) and carriers from other countries enrolled in colonoscopy 2-yearly or more frequently ( n  = 439; 3299 observation years). We examined whether the longer interval between colonoscopies in Finland could explain the high incidence of CRC and whether disease expression correlated with differences in population CRC incidence. Cumulative CRC incidences in carriers of path_MLH1 at 70-years of age were 41% for males and 36% for females in the Finnish series and 58% and 55% in the non-Finnish series, respectively ( p  > 0.05). Mean time from last colonoscopy to CRC was 32.7 months in the Finnish compared to 31.0 months in the non-Finnish (p > 0.05) and was therefore unaffected by the recommended colonoscopy interval. Differences in population incidence of CRC could not explain the lower point estimates for CRC in the Finnish series. Ten-year overall survival after CRC was similar for the Finnish and non-Finnish series (88% and 91%, respectively; p > 0.05). The hypothesis that the high incidence of CRC in path_MLH1 carriers was caused by a higher incidence in the Finnish series was not valid. We discuss whether the results were influenced by methodological shortcomings in our study or whether the assumption that a shorter interval between colonoscopies leads to a lower CRC incidence may be wrong. This second possibility is intriguing, because it suggests the dogma that CRC in path_MLH1 carriers develops from polyps that can be detected at colonoscopy and removed to prevent CRC may be erroneous. In view of the excellent 10-year overall survival in the Finnish and non-Finnish series we remain strong advocates of current surveillance practices for those with LS pending

  13. Characteristics of lentiviral vectors harboring the proximal promoter of the vav proto-oncogene: a weak and efficient promoter for gene therapy.

    Science.gov (United States)

    Almarza, Elena; Río, Paula; Meza, Nestor W; Aldea, Montserrat; Agirre, Xabier; Guenechea, Guillermo; Segovia, José C; Bueren, Juan A

    2007-08-01

    Recent published data have shown the efficacy of gene therapy treatments of certain monogenic diseases. Risks of insertional oncogenesis, however, indicate the necessity of developing new vectors with weaker or cell-restricted promoters to minimize the trans-activation activity of integrated proviruses. We have inserted the proximal promoter of the vav proto-oncogene into self-inactivating lentiviral vectors (vav-LVs) and investigated the expression pattern and therapeutic efficacy of these vectors. Compared with other LVs frequently used in gene therapy, vav-LVs mediated a weak, though homogeneous and stable, expression in in vitro-cultured cells. Transplantation experiments using transduced mouse bone marrow and human CD34(+) cells confirmed the stable activity of the promoter in vivo. To investigate whether the weak activity of this promoter was compatible with a therapeutic effect, a LV expressing the Fanconi anemia A (FANCA) gene was constructed (vav-FANCA LV). Although this vector induced a low expression of FANCA, compared to the expression induced by a LV harboring the spleen focus-forming virus (SFFV) promoter, the two vectors corrected the phenotype of cells from a patient with FA-A with the same efficacy. We propose that self-inactivating vectors harboring weak promoters, such as the vav promoter, will improve the safety of gene therapy and will be of particular interest for the treatment of diseases where a high expression of the transgene is not required.

  14. Analysis of the AHR gene proximal promoter GGGGC-repeat polymorphism in lung, breast, and colon cancer

    International Nuclear Information System (INIS)

    Spink, Barbara C.; Bloom, Michael S.; Wu, Susan; Sell, Stewart; Schneider, Erasmus; Ding, Xinxin; Spink, David C.

    2015-01-01

    The aryl hydrocarbon receptor (AhR) regulates expression of numerous genes, including those of the CYP1 gene family. With the goal of determining factors that control AHR gene expression, our studies are focused on the role of the short tandem repeat polymorphism, (GGGGC) n , located in the proximal promoter of the human AHR gene. When luciferase constructs containing varying GGGGC repeats were transfected into cancer cell lines derived from the lung, colon, and breast, the number of GGGGC repeats affected AHR promoter activity. The number of GGGGC repeats was determined in DNA from 327 humans and from 38 samples representing 5 species of non-human primates. In chimpanzees and 3 species of macaques, only (GGGGC) 2 alleles were observed; however, in western gorilla, (GGGGC) n alleles with n = 2, 4, 5, 6, 7, and 8 were identified. In all human populations examined, the frequency of (GGGGC) n was n = 4 > 5 ≫ 2, 6. When frequencies of the (GGGGC) n alleles in DNA from patients with lung, colon, or breast cancer were evaluated, the occurrence of (GGGGC) 2 was found to be 8-fold more frequent among lung cancer patients in comparison with its incidence in the general population, as represented by New York State neonates. Analysis of matched tumor and non-tumor DNA samples from the same individuals provided no evidence of microsatellite instability. These studies indicate that the (GGGGC) n short tandem repeats are inherited, and that the (GGGGC) 2 allele in the AHR proximal promoter region should be further investigated with regard to its potential association with lung cancer susceptibility. - Highlights: • The AHR proximal promoter contains a polymorphism, (GGGGC) n , where n = 4 > 5 ≫ 2, 6 • Matched tumor and non-tumor DNA did not show (GGGGC) n microsatellite instability • AHR promoter activity of a construct with (GGGGC) 2 was lower than that of (GGGGC) 4 • The frequency of (GGGGC) 2 in lung cancer patients was 8-fold higher than in neonates • The

  15. Analysis of the AHR gene proximal promoter GGGGC-repeat polymorphism in lung, breast, and colon cancer

    Energy Technology Data Exchange (ETDEWEB)

    Spink, Barbara C. [Wadsworth Center, New York State Department of Health, Albany, NY 12201 (United States); Bloom, Michael S. [Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY 12201 (United States); Wu, Susan [Wadsworth Center, New York State Department of Health, Albany, NY 12201 (United States); Sell, Stewart; Schneider, Erasmus [Wadsworth Center, New York State Department of Health, Albany, NY 12201 (United States); Department of Biomedical Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY 12201 (United States); Ding, Xinxin [Wadsworth Center, New York State Department of Health, Albany, NY 12201 (United States); Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY 12201 (United States); Department of Biomedical Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY 12201 (United States); Spink, David C., E-mail: spink@wadsworth.org [Wadsworth Center, New York State Department of Health, Albany, NY 12201 (United States); Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY 12201 (United States)

    2015-01-01

    The aryl hydrocarbon receptor (AhR) regulates expression of numerous genes, including those of the CYP1 gene family. With the goal of determining factors that control AHR gene expression, our studies are focused on the role of the short tandem repeat polymorphism, (GGGGC){sub n}, located in the proximal promoter of the human AHR gene. When luciferase constructs containing varying GGGGC repeats were transfected into cancer cell lines derived from the lung, colon, and breast, the number of GGGGC repeats affected AHR promoter activity. The number of GGGGC repeats was determined in DNA from 327 humans and from 38 samples representing 5 species of non-human primates. In chimpanzees and 3 species of macaques, only (GGGGC){sub 2} alleles were observed; however, in western gorilla, (GGGGC){sub n} alleles with n = 2, 4, 5, 6, 7, and 8 were identified. In all human populations examined, the frequency of (GGGGC){sub n} was n = 4 > 5 ≫ 2, 6. When frequencies of the (GGGGC){sub n} alleles in DNA from patients with lung, colon, or breast cancer were evaluated, the occurrence of (GGGGC){sub 2} was found to be 8-fold more frequent among lung cancer patients in comparison with its incidence in the general population, as represented by New York State neonates. Analysis of matched tumor and non-tumor DNA samples from the same individuals provided no evidence of microsatellite instability. These studies indicate that the (GGGGC){sub n} short tandem repeats are inherited, and that the (GGGGC){sub 2} allele in the AHR proximal promoter region should be further investigated with regard to its potential association with lung cancer susceptibility. - Highlights: • The AHR proximal promoter contains a polymorphism, (GGGGC){sub n}, where n = 4 > 5 ≫ 2, 6 • Matched tumor and non-tumor DNA did not show (GGGGC){sub n} microsatellite instability • AHR promoter activity of a construct with (GGGGC){sub 2} was lower than that of (GGGGC){sub 4} • The frequency of (GGGGC){sub 2} in lung

  16. Secondary mutation in a coding mononucleotide tract in MSH6 causes loss of immunoexpression of MSH6 in colorectal carcinomas with MLH1/PMS2 deficiency.

    Science.gov (United States)

    Shia, Jinru; Zhang, Liying; Shike, Moshe; Guo, Min; Stadler, Zsofia; Xiong, Xiaoling; Tang, Laura H; Vakiani, Efsevia; Katabi, Nora; Wang, Hangjun; Bacares, Ruben; Ruggeri, Jeanine; Boland, C Richard; Ladanyi, Marc; Klimstra, David S

    2013-01-01

    Immunohistochemical staining for DNA mismatch repair proteins may be affected by various biological and technical factors. Staining variations that could potentially lead to erroneous interpretations have been recognized. A recently recognized staining variation is the significant reduction of staining for MSH6 in some colorectal carcinomas. The frequency and specific characteristics of this aberrant MSH6 staining pattern, however, have not been well analyzed. In this study of 420 colorectal carcinoma samples obtained from patients fulfilling the Revised Bethesda Guidelines, we detected 9 tumors (2%) showing extremely limited staining for MSH6 with positive staining present in PMS2 protein-deficient carcinomas (n=5, including 1 with a pathogenic mutation in PMS2); and (2) MLH1, PMS2 and MSH2 normal but with chemotherapy or chemoradiation therapy before surgery (n=4). To test our hypothesis that somatic mutation in the coding region microsatellite of the MSH6 gene might be a potential underlying mechanism for such limited MSH6 staining, we evaluated frameshift mutation in a (C)(8) tract in exon 5 of the MSH6 gene in seven tumors that had sufficient DNA for analysis, and detected mutation in four; all four tumors belonged to the MLH1/PMS2-deficient group. In conclusion, our data outline the main scenarios where significant reduction of MSH6 staining is more likely to occur in colorectal carcinoma, and suggest that somatic mutations of the coding region microsatellites of the MSH6 gene is an underlying mechanism for this staining phenomenon in MLH1/PMS2-deficient carcinomas.

  17. Screening of the DNA mismatch repair genes MLH1, MSH2 and MSH6 in a Greek cohort of Lynch syndrome suspected families

    International Nuclear Information System (INIS)

    Thodi, Georgia; Fountzilas, George; Yannoukakos, Drakoulis; Fostira, Florentia; Sandaltzopoulos, Raphael; Nasioulas, George; Grivas, Anastasios; Boukovinas, Ioannis; Mylonaki, Maria; Panopoulos, Christos; Magic, Mirjana Brankovic

    2010-01-01

    Germline mutations in the DNA mismatch repair genes predispose to Lynch syndrome, thus conferring a high relative risk of colorectal and endometrial cancer. The MLH1, MSH2 and MSH6 mutational spectrum reported so far involves minor alterations scattered throughout their coding regions as well as large genomic rearrangements. Therefore, a combination of complete sequencing and a specialized technique for the detection of genomic rearrangements should be conducted during a proper DNA-testing procedure. Our main goal was to successfully identify Lynch syndrome families and determine the spectrum of MLH1, MSH2 and MSH6 mutations in Greek Lynch families in order to develop an efficient screening protocol for the Greek colorectal cancer patients' cohort. Forty-two samples from twenty-four families, out of which twenty two of Greek, one of Cypriot and one of Serbian origin, were screened for the presence of germline mutations in the major mismatch repair genes through direct sequencing and MLPA. Families were selected upon Amsterdam criteria or revised Bethesda guidelines. Ten deleterious alterations were detected in twelve out of the twenty-four families subjected to genetic testing, thus our detection rate is 50%. Four of the pathogenic point mutations, namely two nonsense, one missense and one splice site change, are novel, whereas the detected genomic deletion encompassing exon 6 of the MLH1 gene has been described repeatedly in the LOVD database. The average age of onset for the development of both colorectal and endometrial cancer among mutation positive families is 43.2 years. The mutational spectrum of the MMR genes investigated as it has been shaped by our analysis is quite heterogeneous without any strong indication for the presence of a founder effect

  18. Altered expression of HER-2 and the mismatch repair genes MLH1 and MSH2 predicts the outcome of T1 high-grade bladder cancer.

    Science.gov (United States)

    Sanguedolce, Francesca; Cormio, Antonella; Massenio, Paolo; Pedicillo, Maria C; Cagiano, Simona; Fortunato, Francesca; Calò, Beppe; Di Fino, Giuseppe; Carrieri, Giuseppe; Bufo, Pantaleo; Cormio, Luigi

    2018-04-01

    The identification of factors predicting the outcome of stage T1 high-grade bladder cancer (BC) is a major clinical issue. We performed immunohistochemistry to assess the role of human epidermal growth factor receptor-2 (HER-2) and microsatellite instability (MSI) factors MutL homologue 1 (MLH1) and MutS homologue 2 (MSH2) in predicting recurrence and progression of T1 high-grade BCs having undergone transurethral resection of bladder tumor (TURBT) alone or TURBT + intravesical instillations of bacillus Calmette-Guerin (BCG). HER-2 overexpression was a significant predictor of disease-free survival (DFS) in the overall as well as in the two patients' population; as for progression-free survival (PFS), it was significant in the overall but not in the two patients' population. MLH1 was an independent predictor of PFS only in patients treated with BCG and MSH2 failed to predict DFS and PFS in all populations. Most importantly, the higher the number of altered markers the lowers the DFS and PFS. In multivariate Cox proportional-hazards regression analysis, the number of altered molecular markers and BCG treatment were significant predictors (p = 0.0004 and 0.0283, respectively) of DFS, whereas the number of altered molecular markers was the only significant predictor (p = 0.0054) of PFS. Altered expression of the proto-oncogene HER-2 and the two molecular markers of genetic instability MLH1 and MSH2 predicted T1 high-grade BC outcome with the higher the number of altered markers the lower the DFS and PFS. These findings provide grounds for further testing them in predicting the outcome of this challenging disease.

  19. Hsp27, Hsp70 and mismatch repair proteins hMLH1 and hMSH2 expression in peripheral blood lymphocytes from healthy subjects and cancer patients.

    Science.gov (United States)

    Nadin, Silvina Beatriz; Vargas-Roig, Laura M; Drago, Gisela; Ibarra, Jorge; Ciocca, Daniel R

    2007-07-08

    Mismatch repair (MMR) deficiency and higher expression levels of heat shock proteins (Hsps) have been implicated with drug resistance to topoisomerase II poisons (doxorubicin) and to platinum compounds (cisplatin). This study was designed to determine individual influences of doxorubicin and cisplatin treatment on the expression of Hsp27, Hsp70, hMLH1 and hMSH2 proteins and in the DNA damage status in peripheral blood lymphocytes (PBLs). In addition, we studied whether these proteins and the DNA damage correlated with the survival of cancer patients. PBLs from 10 healthy donors and 25 cancer patients (before and after three cycles of chemotherapy) were exposed to in vitro treatments: C (control), HS (heat shock at 42 degrees C), Do or Pt (doxorubicin or cisplatin alone), and HS+Do or HS+Pt (heat shock+doxorubicin or heat shock+cisplatin). PBLs were collected at time 0 (T0: immediately after drug treatment) and after 24h of repair (T24). Hsp27, Hsp70, hMLH1 and hMSH2 were studied by immunocytochemistry and the DNA damage by alkaline comet assay. Immunofluorescence studies and confocal microscopy revealed that hMLH1 and hMSH2 colocalized with Hsp27 and Hsp72 (inducible form of Hsp70). hMLH1 and hMSH2 were significantly induced by Pt and HS+Pt at T24 in cancer patients, but only modestly influenced by Do. Cancer patients presented higher basal expression of total and nuclear Hsp27 and Hsp70 than controls, and these proteins were also increased by HS, Do and HS+Do. The Hsp70 induction by Pt and HS+Pt was noted in cancer patients, especially nuclear Hsp70. In cancer patients, basal DNA damage was slightly higher than in healthy persons; and after Pt and HS+Pt treatments, DNA migration and number of apoptotic cells were higher than controls. Hsps accomplished a cytoprotective function in pre-chemotherapy PBLs (HS before Do or Pt), but not in post-chemotherapy samples. In Pt-treated patients the ratio N/C (nuclear/cytoplasmic) of Hsp27 was related to disease free survival

  20. Small suitability of the DLEC1, MLH1 and TUSC4 mRNA expression analysis as potential prognostic or differentiating markers for NSCLC patients in the Polish population.

    Science.gov (United States)

    Kordiak, Jacek; Czarnecka, Karolina H; Pastuszak-Lewandoska, Dorota; Antczak, Adam; Migdalska-Sęk, Monika; Nawrot, Ewa; Domańska-Senderowska, Daria; Kiszałkiewicz, Justyna; Brzeziańska-Lasota, Ewa

    2017-06-01

    According to the latest data, lung cancer is one of the most common cancer worldwide, men contributing nearly 21.2% and women 8.6% of all diagnosed cancers. Late detection of tumour drastically reduces the chance for a cure. Thus, it is important to search for candidate biomarkers for screening of early stage nonsmall cell lung carcinoma (NSCLC). Tumour suppressor genes, DLEC1, TUSC4 and MLH1, localized on 3p21 are recognized to play a role in NSCLC carcinogenesis. The aim of this study was to assess the relationship between the DLEC1, TUSC4 and MLH1 mRNA expression, and clinical features of NSCLC patients, tobacco addiction, and tumour histopathological characteristics. The DLEC1, TUSC4 and MLH1 expression was analysed in lung tumour tissue samples obtained from 69 patients diagnosed with NSCLC: squamous cell carcinoma (n = 34), adenocarcinoma (n = 24), large cell carcinoma (n = 5), carcinoma adenosquamosum (n = 5). A decreased gene expression (RQ MLH1 in 50.7% and for TUSC4 in 26% of NSCLC samples. DLEC1 was decreased in more aggressive subtypes: large cell carcinoma and adenocarcinoma-squamous cell carcinoma. The simultaneous downregulation of two of the studied genes, DLEC1 andMLH1,was observed in 30.4% of NSCLCsamples, highlighting the importance of these two genes in lung carcinogenesis. We found no correlation between the DLEC1, TUSC4 and MLH1 gene expression and NSCLC patient characteristics (gender, age and smoking) or cancer histopathology. No significant differences in the gene expression among NSCLC subtypes indicate the weakness of DLEC1, TUSC4 and MLH1 expression analysis as potential differentiating markers of NSCLC subtypes in the Polish population.

  1. The MLH1 c.1852_1853delinsGC (p.K618A variant in colorectal cancer: genetic association study in 18,723 individuals.

    Directory of Open Access Journals (Sweden)

    Anna Abulí

    Full Text Available Colorectal cancer is one of the most frequent neoplasms and an important cause of mortality in the developed world. Mendelian syndromes account for about 5% of the total burden of CRC, being Lynch syndrome and familial adenomatous polyposis the most common forms. Lynch syndrome tumors develop mainly as a consequence of defective DNA mismatch repair associated with germline mutations in MLH1, MSH2, MSH6 and PMS2. A significant proportion of variants identified by screening these genes correspond to missense or noncoding changes without a clear pathogenic consequence, and they are designated as "variants of uncertain significance", being the c.1852_1853delinsGC (p.K618A variant in the MLH1 gene a clear example. The implication of this variant as a low-penetrance risk variant for CRC was assessed in the present study by performing a case-control study within a large cohort from the COGENT consortium-COST Action BM1206 including 18,723 individuals (8,055 colorectal cancer cases and 10,668 controls and a case-only genotype-phenotype correlation with several clinical and pathological characteristics restricted to the Epicolon cohort. Our results showed no involvement of this variant as a low-penetrance variant for colorectal cancer genetic susceptibility and no association with any clinical and pathological characteristics including family history for this neoplasm or Lynch syndrome.

  2. An Alphavirus E2 Membrane-Proximal Domain Promotes Envelope Protein Lateral Interactions and Virus Budding

    Directory of Open Access Journals (Sweden)

    Emily A. Byrd

    2017-11-01

    Full Text Available Alphaviruses are members of a group of small enveloped RNA viruses that includes important human pathogens such as Chikungunya virus and the equine encephalitis viruses. The virus membrane is covered by a lattice composed of 80 spikes, each a trimer of heterodimers of the E2 and E1 transmembrane proteins. During virus endocytic entry, the E1 glycoprotein mediates the low-pH-dependent fusion of the virus membrane with the endosome membrane, thus initiating virus infection. While much is known about E1 structural rearrangements during membrane fusion, it is unclear how the E1/E2 dimer dissociates, a step required for the fusion reaction. A recent Alphavirus cryo-electron microscopy reconstruction revealed a previously unidentified D subdomain in the E2 ectodomain, close to the virus membrane. A loop within this region, here referred to as the D-loop, contains two highly conserved histidines, H348 and H352, which were hypothesized to play a role in dimer dissociation. We generated Semliki Forest virus mutants containing the single and double alanine substitutions H348A, H352A, and H348/352A. The three D-loop mutations caused a reduction in virus growth ranging from 1.6 to 2 log but did not significantly affect structural protein biosynthesis or transport, dimer stability, virus fusion, or specific infectivity. Instead, growth reduction was due to inhibition of a late stage of virus assembly at the plasma membrane. The virus particles that are produced show reduced thermostability compared to the wild type. We propose the E2 D-loop as a key region in establishing the E1-E2 contacts that drive glycoprotein lattice formation and promote Alphavirus budding from the plasma membrane.

  3. Avaliação da expressão tecidual do gene de reparo MLH1 e dos níveis de dano oxidativo ao DNA em doentes com câncer colorretal Evaluation of expression of mismatch repair gene MLH1 and levels of oxidative DNA damage in normal and neoplastic tissues of patients with colorectal cancer

    Directory of Open Access Journals (Sweden)

    Carlos Augusto Real Martinez

    2009-09-01

    Full Text Available O dano oxidativo ao DNA provocado por radicais livres de oxigênio representa um dos principais mecanismos responsáveis pelas etapas iniciais da carcinogênese colorretal. O estresse oxidativo ocasiona erros de pareamento de bases possibilitando o aparecimento de mutações em genes controladores do ciclo celular. As células possuem um sistema de defesa representado pelos genes de reparo do DNA que corrigindo os erros de pareamento impedem o desenvolvimento de mutações. Poucos estudos avaliaram a relação entre dano oxidativo ao DNA e a expressão tecidual do gene de reparo MLH1. OBJETIVO: O objetivo do presente estudo foi avaliar os níveis de estresse oxidativo ao DNA e a expressão tecidual do gene de reparo MLH1 nas células da mucosa cólica normal e neoplásica de doentes com câncer colorretal. MATERIAL E MÉTODO: Foram estudados 44 doentes com diagnóstico de adenocarcinoma colorretal. Foram excluídos os doentes com câncer colorretal hereditário, portadores de câncer relacionado às doenças inflamatórias intestinais e os submetidos à radioquimioterapia neoadjuvante. Para a avaliação dos níveis de dano oxidativo ao DNA utilizou-se a técnica da eletroforese alcalina em gel de célula isolada (ensaio do cometa avaliando 100 células obtidas dos tecidos normal e neoplásico. Para a avaliação da expressão do gene MLH1 utilizou-se a técnica de reação de polimerase em cadeia em tempo real (RT-PCR com primer especificamente desenhados para amplificação do gene. A comparação dos resultados encontrados para os níveis de estresse oxidativo ao DNA, e expressão do gene MLH1 nos tecidos normais e neoplásicos foi feito pelo teste t de Student, adotando-se nível de significância de 5% (pThe oxidative DNA damage caused by oxygen free radicals is one of the most important mechanisms responsible for the initial steps of colorectal carcinogenesis. The oxidative stress can cause errors in the pairing of nitrogenous bases that

  4. [Immunohistochemical examination of MSH2, PMS2, MLH1, MSH6 compared with the analysis of microsatellite instability in colon adenocarcinoma].

    Science.gov (United States)

    Raskin, G A; Ianus, G A; Kornilov, A V; Orlova, R V; Petrov, S V; Protasova, A É; Pozharisskiĭ, K M; Imianitov, E N

    2014-01-01

    Adenocarcinoma of the colon in 10-20% is associated with microsatellite instability, which can occur both in sporadic cancers and in hereditary nonpolyposis colon cancer. Our analysis of 195 cases of adenocarcinoma of the colon showed that microsatellite instability (MSI-H) was found only in 1.5% of patients. Subsequent choice of patients with suspected hereditary Lynch syndrome led to the identification of additional 17 patients with microsatellite instability. They passed an analysis of genes of repair system of unpaired nucleotides of DNA. The study showed that immunohistochemical staining of MSH2, MSH6, MLH1, PMS2 could effectively conduct a preliminary screening of the Lynch syndrome but was unable to divide cases of sporadic and hereditary MSI-H colon cancer.

  5. Detection and precise mapping of germline rearrangements in BRCA1, BRCA2, MSH2, and MLH1 using zoom-in array comparative genomic hybridization (aCGH)

    DEFF Research Database (Denmark)

    Staaf, Johan; Törngren, Therese; Rambech, Eva

    2008-01-01

    Disease-predisposing germline mutations in cancer susceptibility genes may consist of large genomic rearrangements that are challenging to detect and characterize using standard PCR-based mutation screening methods. Here, we describe a custom-made zoom-in microarray comparative genomic hybridizat......Disease-predisposing germline mutations in cancer susceptibility genes may consist of large genomic rearrangements that are challenging to detect and characterize using standard PCR-based mutation screening methods. Here, we describe a custom-made zoom-in microarray comparative genomic...... deletions or duplications occurring in BRCA1 (n=11), BRCA2 (n=2), MSH2 (n=7), or MLH1 (n=9). Additionally, we demonstrate its applicability for uncovering complex somatic rearrangements, exemplified by zoom-in analysis of the PTEN and CDKN2A loci in breast cancer cells. The sizes of rearrangements ranged...... from several 100 kb, including large flanking regions, to rearrangements, allowing convenient design...

  6. The importance of proper bioinformatics analysis and clinical interpretation of tumor genomic profiling: a case study of undifferentiated sarcoma and a constitutional pathogenic BRCA2 mutation and an MLH1 variant of uncertain significance.

    Science.gov (United States)

    Varga, Elizabeth; Chao, Elizabeth C; Yeager, Nicholas D

    2015-09-01

    Next-generation sequencing (NGS) technology is increasingly utilized to identify therapeutic targets for patients with malignancy. This technology also has the capability to reveal the presence of constitutional genetic alterations, which may have significant implications for patients and their family members. Here we present the case of a 23 year old Caucasian patient with recurrent undifferentiated sarcoma who had NGS-based tumor analysis using an assay which simultaneously analyzed the entire coding sequence of 236 cancer-related genes (3769 exons) plus 47 introns from 19 genes often rearranged or altered in cancer. Pathogenic alterations were reported in tumor as the predicted protein alterations, BRCA2 "R645fs*15″ and MLH1 "E694*". Because constitutional BRCA2 and MLH1 gene mutations are associated with Hereditary Breast Ovarian Cancer Syndrome (HBOCS) and Lynch syndrome respectively, sequence analysis of DNA isolated from peripheral blood was performed. The presence of the alterations, BRCA2 c.1929delG and MLH1 c.2080G>T, corresponding to the previously reported predicted protein alterations, were confirmed by Sanger sequencing in the constitutional DNA. An additional DNA finding was reported in this analysis, MLH1 c.2081A>C at the neighboring nucleotide. Further evaluation of the family revealed that all alterations were paternally inherited and the two MLH1 substitutions were in cis, more appropriately referred to as MLH1 c.2080_2081delGAinsTC, which is classified as a variant of uncertain significance. This case illustrates important considerations related to appropriate interpretation of NGS tumor results and follow-up of patients with potentially deleterious constitutional alterations.

  7. Evidence for classification of c.1852_1853AA>GC in MLH1 as a neutral variant for Lynch syndrome

    Directory of Open Access Journals (Sweden)

    Llor Xavier

    2011-01-01

    Full Text Available Abstract Background Lynch syndrome (LS is an autosomal dominant inherited cancer syndrome characterized by early onset cancers of the colorectum, endometrium and other tumours. A significant proportion of DNA variants in LS patients are unclassified. Reports on the pathogenicity of the c.1852_1853AA>GC (p.Lys618Ala variant of the MLH1 gene are conflicting. In this study, we provide new evidence indicating that this variant has no significant implications for LS. Methods The following approach was used to assess the clinical significance of the p.Lys618Ala variant: frequency in a control population, case-control comparison, co-occurrence of the p.Lys618Ala variant with a pathogenic mutation, co-segregation with the disease and microsatellite instability in tumours from carriers of the variant. We genotyped p.Lys618Ala in 1034 individuals (373 sporadic colorectal cancer [CRC] patients, 250 index subjects from families suspected of having LS [revised Bethesda guidelines] and 411 controls. Three well-characterized LS families that fulfilled the Amsterdam II Criteria and consisted of members with the p.Lys618Ala variant were included to assess co-occurrence and co-segregation. A subset of colorectal tumour DNA samples from 17 patients carrying the p.Lys618Ala variant was screened for microsatellite instability using five mononucleotide markers. Results Twenty-seven individuals were heterozygous for the p.Lys618Ala variant; nine had sporadic CRC (2.41%, seven were suspected of having hereditary CRC (2.8% and 11 were controls (2.68%. There were no significant associations in the case-control and case-case studies. The p.Lys618Ala variant was co-existent with pathogenic mutations in two unrelated LS families. In one family, the allele distribution of the pathogenic and unclassified variant was in trans, in the other family the pathogenic variant was detected in the MSH6 gene and only the deleterious variant co-segregated with the disease in both

  8. Determination of single-nucleotide polymorphism in the proximal promoter region of apolipoprotein M gene in coronary artery diseases

    Directory of Open Access Journals (Sweden)

    Lu Zheng

    2009-09-01

    Full Text Available Lu Zheng1, Guanghua Luo1, Xiaoying Zhang1, Jun Zhang1, Jiang Zhu1, Jiang Wei1, Qinfeng Mu1, Lujun Chen1, Peter Nilsson-Ehle2, Ning Xu21Comprehensive Laboratory, The Third Affiliated Hospital, Suzhou University, Changzhou China; 2Division of Clinical Chemistry and Pharmacology, Department of Laboratory Medicine, Lund University, Lund, SwedenObjective: It has been reported that single-nucleotide polymorphism (SNP in the proximal promoter region of apolipoprotein M (apoM gene may confer the risk in the development of type 2 diabetes (T2D and coronary artery disease (CAD in the Han Chinese. However, in a recent study demonstrated that plasma apoM level did not correlated to the coronary heart disease. In the present studies, we investigated the SNP T-778C of apoM gene in CAD patients and controls in the Han Chinese population. Moreover we examined whether serum apoM levels could be influenced by this promoter mutation.Material and methods: One hundred twenty-six CAD patients and 118 non-CAD patients were subjected in the present study. All patients were confirmed by the angiography. The genotyping of polymorphisms T-778C in apoM promoter was determined by real-time polymerase chain reaction. Serum apoM levels were semi-quantitatively determined by the dot-blotting analysis. Results: Distribution of apoM T-778C genotype in non-CAD patients was as following: 84.7% were T/T, 15.3% were T/C and 0.0% was C/C. T allele frequencies were 92.4% and C allele, 7.6%. In the CAD patients, 99 patients (78.6% had the T/T genotype, 25 patients (19.8% with T/C genotype and 2 patients (1.6% with C/C genotype. The allele frequency was 88.5% for the T allele and 11.5% for the C allele. There was no statistical significant difference of serum apoM levels found in these three genotypes.Conclusions: There was no significant difference in allele or genotype frequencies between CAD patients and non-CAD patients. Binary logistic regression analysis with adjustments for age

  9. Characterization of the FoxL2 proximal promoter and coding sequence from the common snapping turtle (Chelydra serpentina).

    Science.gov (United States)

    Guo, Lei; Rhen, Turk

    2017-10-01

    Sex is determined by temperature during embryogenesis in snapping turtles, Chelydra serpentina. Previous studies in this species show that dihydrotestosterone (DHT) induces ovarian development at temperatures that normally produce males or mixed sex ratios. The feminizing effect of DHT is associated with increased expression of FoxL2, suggesting that androgens regulate transcription of FoxL2. To test this hypothesis, we cloned the proximal promoter (1.6kb) and coding sequence for snapping turtle FoxL2 (tFoxL2) in frame with mCherry to produce a fluorescent reporter. The tFoxL2-mCherry fusion plasmid or mCherry control plasmid were stably transfected into mouse KK1 granulosa cells. These cells were then treated with 0, 1, 10, or 100nM DHT to assess androgen effects on tFoxL2-mCherry expression. In contrast to the main hypothesis, DHT did not alter expression of the tFoxL2-mCherry reporter. However, normal serum increased expression of tFoxL2-mCherry when compared to charcoal-stripped serum, indicating that the cloned region of tFoxL2 contains cis regulatory elements. We also used the tFoxL2-mCherry plasmid as an expression vector to test the hypothesis that DHT and tFoxL2 interact to regulate expression of endogenous genes in granulosa cells. While tFoxL2-mCherry and DHT had independent effects on mouse FoxL2, FshR, GnRHR, and StAR expression, tFoxL2-mCherry potentiated low concentration DHT effects on mouse aromatase expression. Further studies will be required to determine whether synergistic regulation of aromatase by DHT and FoxL2 also occurs in turtle gonads during the sex-determining period, which would explain the feminizing effect of DHT in this species. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Mismatch Repair Proteins and Microsatellite Instability in Colorectal Carcinoma (MLH1, MSH2, MSH6 and PMS2): Histopathological and Immunohistochemical Study.

    Science.gov (United States)

    Ismael, Nour El Hoda S; El Sheikh, Samar A; Talaat, Suzan M; Salem, Eman M

    2017-03-15

    Colorectal cancer (CRC) is one of the most common cancers worldwide. Microsatellite instability (MSI) is detected in about 15% of all colorectal cancers. CRC with MSI has particular characteristics such as improved survival rates and better prognosis. They also have a distinct sensitivity to the action of chemotherapy. The aim of the study was to detect microsatellite instability in a cohort of colorectal cancer Egyptian patients using the immunohistochemical expression of mismatch repair proteins (MLH1, MSH2, MSH6 and PMS2). Cases were divided into Microsatellite stable (MSS), Microsatellite unstable low (MSI-L) and Microsatellite unstable high (MSI-H). This Microsatellite stability status was correlated with different clinicopathological parameters. There was a statistically significant correlation between the age of cases, tumor site & grade and the microsatellite stability status. There was no statistically significant correlation between the gender of patients, tumor subtype, stage, mucoid change, necrosis, tumor borders, lymphocytic response, lymphovascular emboli and the microsatellite stability status. Testing for MSI should be done for all colorectal cancer patients, especially those younger than 50 years old, right sided and high-grade CRCs.

  11. Tissue expression of MLH1, PMS2, MSH2, and MSH6 proteins and prognostic value of microsatellite instability in Wilms tumor: experience of 45 cases.

    Science.gov (United States)

    Diniz, Gulden; Aktas, Safiye; Cubuk, Cankut; Ortac, Ragip; Vergin, Canan; Olgun, Nur

    2013-05-01

    Although the importance of microsatellite instability (MSI) and mismatch repair genes (MMR) is strongly established in colorectal cancer seen in the Lynch syndrome, its significance has not been fully established in Wilms tumor (WT). The aim of this study was to determine the prognostic value of MSI and MMR proteins in WT. This study included 45 pediatric cases with nephroblastoma. Protein expression was analyzed by immunohistochemistry of archival tissue sections. Real-time PCR melting analysis and fluorescence capillary electrophoresis (FCE) were performed to evaluate the MSI markers BAT25, BAT26, NR21, NR24, MONO27, penta D, and penta C in DNA extracted from tumor and normal tissues. Lower levels of MSI were observed in six cases (13.3%). There were no statistically significant correlations between MSI and some clinical prognostic factors such as stage of the tumors, and survival rates. Nineteen tumors (42.2%) showed loss of protein expression of MLH1, PMS2, MSH2, or MSH6. MMR protein defects were correlated with size (P = .021), and stage (P = .019) of the tumor, and survival rates (P < .01).Similarly MSI was also correlated with the size of the tumor (P = .046). This study showed that a small proportion of WT might be associated with the presence of MSI, as is the case with defects of DNA mismatch repair genes in the pathogenesis of WT. However, there was no concordance with the frequency of tissue expression of MMR proteins and MSI. These findings suggest that MMR genes may play an important role in the development of WT via different pathways.

  12. Risk Factors Associated with Colorectal Cancer in a Subset of Patients with Mutations in MLH1 and MSH2 in Taiwan Fulfilling the Amsterdam II Criteria for Lynch Syndrome.

    Directory of Open Access Journals (Sweden)

    Abram Bunya Kamiza

    Full Text Available Lynch syndrome, caused by germline mutations in mismatch repair genes, is a predisposing factor for colorectal cancer (CRC. This retrospective cohort study investigated the risk factors associated with the development of CRC in patients with MLH1 and MSH2 germline mutations.In total, 301 MLH1 and MSH2 germline mutation carriers were identified from the Amsterdam criteria family registry provided by the Taiwan Hereditary Nonpolyposis Colorectal Cancer Consortium. A Cox proportional hazard model was used to calculate the hazard ratios (HRs and 95% confidence intervals (CIs to determine the association between the risk factors and CRC development. A robust sandwich covariance estimation model was used to evaluate family dependence.Among the total cohort, subjects of the Hakka ethnicity exhibited an increased CRC risk (HR = 1.62, 95% CI = 1.09-2.34; however, those who performed regular physical activity exhibited a decreased CRC risk (HR = 0.62, 95% CI = 0.41-0.88. The CRC risk was enhanced in MLH1 germline mutation carriers, with corresponding HRs of 1.72 (95% CI = 1.16-2.55 and 0.54 (95% CI = 0.34-0.83 among subjects of the Hakka ethnicity and those who performed regular physical activity, respectively. In addition, the total cohort with a manual occupation had a 1.56 times higher CRC risk (95% CI = 1.07-2.27 than did that with a skilled occupation. Moreover, MSH2 germline mutation carriers with blood group type B exhibited an increased risk of CRC development (HR = 2.64, 95% CI = 1.06-6.58 compared with those with blood group type O.The present study revealed that Hakka ethnicity, manual occupation, and blood group type B were associated with an increased CRC risk, whereas regular physical activity was associated with a decreased CRC risk in MLH1 and MSH2 germline mutation carriers.

  13. Distal, not proximal, colonic acetate infusions promote fat oxidation and improve metabolic markers in overweight/obese men

    DEFF Research Database (Denmark)

    van der Beek, Christina M; Canfora, Emanuel E; Lenaerts, Kaatje

    2016-01-01

    , circulating hormones or inflammatory markers. In conclusion distal colonic acetate infusions affected whole-body substrate metabolism, with a pronounced increase in fasting fat oxidation and plasma PYY. Modulating colonic acetate may be a nutritional target to treat or prevent metabolic disorders.......Gut microbial-derived short-chain fatty acids (SCFA) are believed to affect host metabolism and cardiometabolic risk factors. The present study aim was to investigate the effects of proximal and distal colonic infusions with the SCFA acetate on fat oxidation and other metabolic parameters in men...... in the colon for three consecutive test days, enabling colonic acetate (100 or 180 mmol/l) or placebo infusion during fasting conditions and after an oral glucose load (postprandial). Fat oxidation and energy expenditure were measured using an open-circuit ventilated hood system and blood samples were...

  14. Chromatin immunoprecipitation assays revealed CREB and serine 133 phospho-CREB binding to the CART gene proximal promoter.

    Science.gov (United States)

    Rogge, George A; Shen, Li-Ling; Kuhar, Michael J

    2010-07-16

    Both over expression of cyclic AMP response element binding protein (CREB) in the nucleus accumbens (NAc), and intra-accumbal injection of cocaine- and amphetamine-regulated transcript (CART) peptides, have been shown to decrease cocaine reward. Also, over expression of CREB in the rat NAc increased CART mRNA and peptide levels, but it is not known if this was due to a direct action of P-CREB on the CART gene promoter. The goal of this study was to test if CREB and P-CREB bound directly to the CRE site in the CART promoter, using chromatin immunoprecipitation (ChIP) assays. ChIP assay with anti-CREB antibodies showed an enrichment of the CART promoter fragment containing the CRE region over IgG precipitated material, a non-specific control. Forskolin, which was known to increase CART mRNA levels in GH3 cells, was utilized to show that the drug increased levels of P-CREB protein and P-CREB binding to the CART promoter CRE-containing region. A region of the c-Fos promoter containing a CRE cis-regulatory element was previously shown to bind P-CREB, and it was used here as a positive control. These data suggest that the effects of CREB over expression on blunting cocaine reward could be, at least in part, attributed to the increased expression of the CART gene by direct interaction of P-CREB with the CART promoter CRE site, rather than by some indirect action. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  15. Down-regulation of human topoisomerase IIα expression correlates with relative amounts of specificity factors Sp1 and Sp3 bound at proximal and distal promoter regions

    Directory of Open Access Journals (Sweden)

    Isaacs Richard J

    2007-05-01

    Full Text Available Abstract Background Topoisomerase IIα has been shown to be down-regulated in doxorubicin-resistant cell lines. The specificity proteins Sp1 and Sp3 have been implicated in regulation of topoisomerase IIα transcription, although the mechanism by which they regulate expression is not fully understood. Sp1 has been shown to bind specifically to both proximal and distal GC elements of the human topoisomerase IIα promoter in vitro, while Sp3 binds only to the distal GC element unless additional flanking sequences are included. While Sp1 is thought to be an activator of human topoisomerase IIα, the functional significance of Sp3 binding is not known. Therefore, we sought to determine the functional relationship between Sp1 and Sp3 binding to the topoisomerase IIα promoter in vivo. We investigated endogenous levels of Sp1, Sp3 and topoisomerase IIα as well as binding of both Sp1 and Sp3 to the GC boxes of the topoisomerase IIα promoter in breast cancer cell lines in vivo after short term doxorubicin exposure. Results Functional effects of Sp1 and Sp3 were studied using transient cotransfection assays using a topoisomerase IIα promoter reporter construct. The in vivo interactions of Sp1 and Sp3 with the GC elements of the topoisomerase IIα promoter were studied in doxorubicin-treated breast cancer cell lines using chromatin immunoprecipitation assays. Relative amounts of endogenous proteins were measured using immunoblotting. In vivo DNA looping mediated by proteins bound at the GC1 and GC2 elements was studied using the chromatin conformation capture assay. Both Sp1 and Sp3 bound to the GC1 and GC2 regions. Sp1 and Sp3 were transcriptional activators and repressors respectively, with Sp3 repression being dominant over Sp1-mediated activation. The GC1 and GC2 elements are linked in vivo to form a loop, thus bringing distal regulatory elements and their cognate transcription factors into close proximity with the transcription start site

  16. Proximal Humerus

    NARCIS (Netherlands)

    Diercks, Ron L.; Bain, Gregory; Itoi, Eiji; Di Giacomo, Giovanni; Sugaya, Hiroyuki

    2015-01-01

    This chapter describes the bony structures of the proximal humerus. The proximal humerus is often regarded as consisting of four parts, which assists in understanding function and, more specially, describes the essential parts in reconstruction after fracture or in joint replacement. These are the

  17. A study of the frequency of methylation of gene promoter regions in ...

    Indian Academy of Sciences (India)

    2013-04-02

    Apr 2, 2013 ... colorectal cancer in the Taiwanese population. CHANG-CHIEH WU1 ... hypermethylation of promoter-region CpG islands is an important ... mismatch repair gene MLH1 plays an important role in dele- ..... Asia Pac. J. Clin.

  18. Cap-proximal nucleotides via differential eIF4E binding and alternative promoter usage mediate translational response to energy stress.

    Science.gov (United States)

    Tamarkin-Ben-Harush, Ana; Vasseur, Jean-Jacques; Debart, Françoise; Ulitsky, Igor; Dikstein, Rivka

    2017-02-08

    Transcription start-site (TSS) selection and alternative promoter (AP) usage contribute to gene expression complexity but little is known about their impact on translation. Here we performed TSS mapping of the translatome following energy stress. Assessing the contribution of cap-proximal TSS nucleotides, we found dramatic effect on translation only upon stress. As eIF4E levels were reduced, we determined its binding to capped-RNAs with different initiating nucleotides and found the lowest affinity to 5'cytidine in correlation with the translational stress-response. In addition, the number of differentially translated APs was elevated following stress. These include novel glucose starvation-induced downstream transcripts for the translation regulators eIF4A and Pabp, which are also translationally-induced despite general translational inhibition. The resultant eIF4A protein is N-terminally truncated and acts as eIF4A inhibitor. The induced Pabp isoform has shorter 5'UTR removing an auto-inhibitory element. Our findings uncovered several levels of coordination of transcription and translation responses to energy stress.

  19. The far and distal enhancers in the CYP3A4 gene co-ordinate the proximal promoter in responding similarly to the pregnane X receptor but differentially to hepatocyte nuclear factor-4alpha.

    Science.gov (United States)

    Liu, Fu-Jun; Song, Xiulong; Yang, Dongfang; Deng, Ruitang; Yan, Bingfang

    2008-01-01

    CYP3A4 (cytochrome P450 3A4) is involved in the metabolism of more than 50% of drugs and other xenobiotics. The expression of CYP3A4 is induced by many structurally dissimilar compounds. The PXR (pregnane X receptor) is recognized as a key regulator for the induction, and the PXR-directed transactivation of the CYP3A4 gene is achieved through a co-ordinated mechanism of the distal module with the proximal promoter. Recently, a far module was found to support constitutive expression of CYP3A4. The far module, like the distal module, is structurally clustered by a PXR response element (F-ER6) and elements recognized by HNF-4alpha (hepatocyte nuclear receptor-4alpha). We hypothesized that the far module supports PXR transactivation of the CYP3A4 gene. Consistent with the hypothesis, fusion of the far module to the proximal promoter of CYP3A4 markedly increased rifampicin-induced reporter activity. The increase was synergistically enhanced when both the far and distal modules were fused to the proximal promoter. The increase, however, was significantly reduced when the F-ER6 was disrupted. Chromatin immunoprecipitation detected the presence of PXR in the far module. Interestingly, HNF-4alpha increased the activity of the distal-proximal fused promoter, but decreased the activity of the far-proximal fused promoter. Given the fact that induction of CYP3A4 represents an important detoxification mechanism, the functional redundancy and synergistic interaction in supporting PXR transactivation suggest that the far and distal modules ensure the induction of CYP3A4 during chemical insults. The difference in responding to HNF-4alpha suggests that the magnitude of the induction is under control through various transcriptional networks.

  20. Up-regulation of mismatch repair genes MSH6, PMS2 and MLH1 parallels development of genetic instability and is linked to tumor aggressiveness and early PSA recurrence in prostate cancer.

    Science.gov (United States)

    Wilczak, Waldemar; Rashed, Semin; Hube-Magg, Claudia; Kluth, Martina; Simon, Ronald; Büscheck, Franziska; Clauditz, Till Sebastian; Grupp, Katharina; Minner, Sarah; Tsourlakis, Maria Christina; Möller-Koop, Christina; Graefen, Markus; Adam, Meike; Haese, Alexander; Wittmer, Corinna; Sauter, Guido; Izbicki, Jakob Robert; Huland, Hartwig; Schlomm, Thorsten; Steurer, Stefan; Krech, Till; Lebok, Patrick

    2017-01-01

    DNA mismatch repair (MMR) is integral to the maintenance of genetic stability. We aimed to evaluate the clinical impact of MMR gene expression in prostate cancer. The MMR genes MSH6, MLH1 and PMS2 were analyzed by immunohistochemistry on a tissue microarray containing 11152 prostate cancer specimens. Results were compared with ETS-related gene status and deletions of PTEN, 3p13, 5q21 and 6q15. MSH6, MLH1 and PMS2 expression was detectable in 89.5%, 85.4% and 85.0% of cancers and was particularly strong in cancers with advanced pathological tumor stage (P < 0.0001 each), high Gleason grade (P < 0.0001 each), nodal metastasis (P ≤ 0.0083) and early biochemical recurrence (P < 0.0001). High levels of MMR gene expression paralleled features of genetic instability, such as the number of genomic deletions per cancer; strong expression of all three MMR genes was found in 24%, 29%, 30%, 33% and 42% of cancers with no, one, two, three or four to five deletions (P < 0.0001). The prognostic value of the analyzed MMR genes was largely driven by the subset of cancers lacking ERG fusion (P < 0.0001), while the prognostic impact of MMR gene overexpression was only marginal in ERG-positive cancers. Multivariate analyses suggested an independent prognostic relevance of MMR genes in ERG-negative prostate cancers when compared with prognostic parameters available at the time of initial biopsy. In conclusion, MMR overexpression is common in prostate cancer and is linked to poor outcome as well as features indicating genetic instability. ERG fusion should be analyzed along with MMR gene expression in potential clinical tests. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Transcriptional Inhibition of Matrix Metal loproteinase 9 (MMP-9 Activity by a c-fos/Estrogen Receptor Fusion Protein is Mediated by the Proximal AP-1 Site of the MMP-9 Promoter and Correlates with Reduced Tumor Cell Invasion

    Directory of Open Access Journals (Sweden)

    David L. Crowe

    1999-10-01

    Full Text Available Tumor cell invasion of basement membranes is one of the hallmarks of malignant transformation. Tumor cells secrete proteolytic enzymes known as matrix metalloproteinases (MMPs which degrade extracellular matrix molecules. Increased expression of MMP-9 has been associated with acquisition of invasive phenotype in many tumors. However, multiple mechanisms for regulation of MMP-9 gene expression by tumor cell lines have been proposed. A number of transcription factor binding sites have been characterized in the upstream regulatory region of the MMP-9 gene, including those for AP-1. To determine how a specific AP-1 family member, c-fos, regulates MMP-9 promoter activity through these sites, we used an expression vector containing the c-fos coding region fused to the estrogen receptor (ER ligand binding domain. This construct is activated upon binding estradiol. Stable expression of this construct in ER negative squamous cell carcinoma (SCC lines produced an estradiol dependent decrease in the number of cells that migrated through a reconstituted basement membrane. This decreased invasiveness was accompanied by estradiol dependent downregulation of MMP-9 activity as determined by gelatin zymography. Estradiol also produced transcriptional downregulation of an MMP-9 promoter construct in cells transiently transfected with the c-fosER expression vector. This downregulation was mediated by the AP-1 site at —79 by in the MMP-9 promoter. We concluded that the proximal AP-1 site mediated the transcriptional downregulation of the MMP-9 promoter by a conditionally activated c-fos fusion protein.

  2. A protein binding AT-rich sequence in the soybean leghemoglobin c3 promoter is a general cis element that requires proximal DNA elements to stimulate transcription

    DEFF Research Database (Denmark)

    Laursen, N B; Larsen, K; Knudsen, J Y

    1994-01-01

    in combination with other trans-acting factor(s) to increase expression. The finding of NAT2-like binding activities in different plant organs and the specific expression of the hybrid NAT2 BS1/-312 rbcS-8B promoter in leaves suggest that NAT2 is a general activator of transcription. Udgivelsesdato: 1994-May...

  3. Association Between Genetic Polymorphisms in the XRCC1, XRCC3, XPD, GSTM1, GSTT1, MSH2, MLH1, MSH3, and MGMT Genes and Radiosensitivity in Breast Cancer Patients

    International Nuclear Information System (INIS)

    Mangoni, Monica; Bisanzi, Simonetta; Carozzi, Francesca; Sani, Cristina; Biti, Giampaolo; Livi, Lorenzo; Barletta, Emanuela; Costantini, Adele Seniori; Gorini, Giuseppe

    2011-01-01

    Purpose: Clinical radiosensitivity varies considerably among patients, and radiation-induced side effects developing in normal tissue can be therapy limiting. Some single nucleotide polymorphisms (SNPs) have been shown to correlate with hypersensitivity to radiotherapy. We conducted a prospective study of 87 female patients with breast cancer who received radiotherapy after breast surgery. We evaluated the association between acute skin reaction following radiotherapy and 11 genetic polymorphisms in DNA repair genes: XRCC1 (Arg399Gln and Arg194Trp), XRCC3 (Thr241Met), XPD (Asp312Asn and Lys751Gln), MSH2 (gIVS12-6T>C), MLH1 (Ile219Val), MSH3 (Ala1045Thr), MGMT (Leu84Phe), and in damage-detoxification GSTM1 and GSTT1 genes (allele deletion). Methods and Materials: Individual genetic polymorphisms were determined by polymerase chain reaction and single nucleotide primer extension for single nucleotide polymorphisms or by a multiplex polymerase chain reaction assay for deletion polymorphisms. The development of severe acute skin reaction (moist desquamation or interruption of radiotherapy due to toxicity) associated with genetic polymorphisms was modeled using Cox proportional hazards, accounting for cumulative biologically effective radiation dose. Results: Radiosensitivity developed in eight patients and was increased in carriers of variants XRCC3-241Met allele (hazard ratio [HR] unquantifiably high), MSH2 gIVS12-6nt-C allele (HR = 53.36; 95% confidence intervals [95% CI], 3.56-798.98), and MSH3-1045Ala allele (HR unquantifiably high). Carriers of XRCC1-Arg194Trp variant allele in combination with XRCC1-Arg399Gln wild-type allele had a significant risk of radiosensitivity (HR = 38.26; 95% CI, 1.19-1232.52). Conclusions: To our knowledge, this is the first report to find an association between MSH2 and MSH3 genetic variants and the development of radiosensitivity in breast cancer patients. Our findings suggest the hypothesis that mismatch repair mechanisms may be

  4. The Flavonoid Apigenin Ameliorates Cisplatin-Induced Nephrotoxicity through Reduction of p53 Activation and Promotion of PI3K/Akt Pathway in Human Renal Proximal Tubular Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Sung Min Ju

    2015-01-01

    Full Text Available Apigenin is a member of the flavone subclass of flavonoids present in fruits and vegetables. Apigenin has long been considered to have various biological activities, such as antioxidant, anti-inflammatory, and antitumorigenic properties, in various cell types. Cisplatin was known to exhibit cytotoxic effect to renal cells by inducing apoptosis through activation of p53. The present study investigated the antiapoptotic effects of apigenin on the cisplatin-treated human renal proximal tubular epithelial (HK-2 cells. HK-2 cells were pretreated with apigenin (5, 10, 20 μM for 1 h and then treated with 40 μM cisplatin for various times. Apigenin inhibited the cisplatin-induced apoptosis of HK-2 cells. Interestingly, apigenin itself exerted cytostatic activity because of its ability to induce cell cycle arrest. Apigenin inhibited caspase-3 activity and PARP cleavage in cisplatin-treated cells. Apigenin reduced cisplatin-induced phosphorylation and expression of p53, with no significant influence on production of ROS that is known to induce p53 activation. Furthermore, apigenin promoted cisplatin-induced Akt phosphorylation, suggesting that enhanced Akt activation may be involved in cytoprotection. Taken together, these results suggest that apigenin ameliorates cisplatin-induced apoptosis through reduction of p53 activation and promotion of PI3K/Akt pathway in HK-2 cells.

  5. Detección de mutaciones de los genes hMLH1 y hMSH2 del sistema de reparación de malos apareamientos del ADN en familias colombianas sospechosas de cancer colorrectal no polipósico hereditario (síndrome de Lynch.

    Directory of Open Access Journals (Sweden)

    Andrea Gómez

    2005-09-01

    Full Text Available Introducción. El cáncer colorrectal es la segunda causa de morbilidad y mortalidad por cáncer en los países desarrollados. En Colombia es la quinta causa de muerte entre los diferentes cánceres. Cerca del 75% de éstos corresponde a cánceres esporádicos, alrededor del 25% son familiares, y son claramente hereditarios el 5%. De éstos, el más importantes es el cáncer colorrectal no polipósico hereditario o síndrome de Lynch. Objetivo. Analizar los dos genes más importantes involucrados en el síndrome de Lynch, el hMLH1 y el hMSH2. Materiales y métodos. En 17 familias colombianas que cumplían con los criterios de Ámsterdam II o las pautas de Bethesda, se analizaron por SSCP los 35 exones de estos dos genes y las variantes electroforéticas se secuenciaron. Resultados. Se detectaron 8 mutaciones de línea germinal en las familias analizadas, 7 en el gen hMLH1 y 1 en hMSH2, y se encontró una tasa de detección de mutaciones del 47%. Seis de las 8 mutaciones encontradas en este estudio han sido previamente reportadas en la literatura. Un cambio de una base en el sitio donador de empalme en el exón 9 del gen hMLH1 (G>A (dos familias, un cambio A>G en el codón 755 del exón 17, y un cambio G>A en el exón 18. Se detectaron dos nuevas mutaciones, una en el exón 17, un cambio C>T en el codón 640, y una deleción de TG en el codón 184 del exón 3 del gen hMSH2. También se detectó en dos familias un polimorfismo del intrón 13 del hMLH1. Conclusión. Este es el primer estudio realizado en Colombia que detecta mutaciones en el síndrome de Lynch y pretende establecer un programa integral de manejo y prevención.

  6. Proximity credentials: A survey

    International Nuclear Information System (INIS)

    Wright, L.J.

    1987-04-01

    Credentials as a means of identifying individuals have traditionally been a photo badge and more recently, the coded credential. Another type of badge, the proximity credential, is making inroads in the personnel identification field. This badge can be read from a distance instead of being veiewed by a guard or inserted into a reading device. This report reviews proximity credentials, identifies the companies marketing or developing proximity credentials, and describes their respective credentials. 3 tabs

  7. Proximal Probes Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Proximal Probes Facility consists of laboratories for microscopy, spectroscopy, and probing of nanostructured materials and their functional properties. At the...

  8. Neighborhoods and manageable proximity

    Directory of Open Access Journals (Sweden)

    Stavros Stavrides

    2011-08-01

    Full Text Available The theatricality of urban encounters is above all a theatricality of distances which allow for the encounter. The absolute “strangeness” of the crowd (Simmel 1997: 74 expressed, in its purest form, in the absolute proximity of a crowded subway train, does not generally allow for any movements of approach, but only for nervous hostile reactions and submissive hypnotic gestures. Neither forced intersections in the course of pedestrians or vehicles, nor the instantaneous crossing of distances by the technology of live broadcasting and remote control give birth to places of encounter. In the forced proximity of the metropolitan crowd which haunted the city of the 19th and 20th century, as well as in the forced proximity of the tele-presence which haunts the dystopic prospect of the future “omnipolis” (Virilio 1997: 74, the necessary distance, which is the stage of an encounter between different instances of otherness, is dissipated.

  9. Proximal collagenous gastroenteritides:

    DEFF Research Database (Denmark)

    Nielsen, Ole Haagen; Riis, Lene Buhl; Danese, Silvio

    2014-01-01

    AIM: While collagenous colitis represents the most common form of the collagenous gastroenteritides, the collagenous entities affecting the proximal part of the gastrointestinal tract are much less recognized and possibly overlooked. The aim was to summarize the latest information through a syste...

  10. Proximal femoral fractures

    DEFF Research Database (Denmark)

    Palm, Henrik; Teixidor, Jordi

    2015-01-01

    searched the homepages of the national heath authorities and national orthopedic societies in West Europe and found 11 national or regional (in case of no national) guidelines including any type of proximal femoral fracture surgery. RESULTS: Pathway consensus is outspread (internal fixation for un...

  11. Proximate Analysis of Coal

    Science.gov (United States)

    Donahue, Craig J.; Rais, Elizabeth A.

    2009-01-01

    This lab experiment illustrates the use of thermogravimetric analysis (TGA) to perform proximate analysis on a series of coal samples of different rank. Peat and coke are also examined. A total of four exercises are described. These are dry exercises as students interpret previously recorded scans. The weight percent moisture, volatile matter,…

  12. Quantum Proximity Resonances

    International Nuclear Information System (INIS)

    Heller, E.J.

    1996-01-01

    It is well known that at long wavelengths λ an s-wave scatterer can have a scattering cross section σ on the order of λ 2 , much larger than its physical size, as measured by the range of its potential. Very interesting phenomena can arise when two or more identical scatterers are placed close together, well within one wavelength. We show that, for a pair of identical scatterers, an extremely narrow p-wave open-quote open-quote proximity close-quote close-quote resonance develops from a broader s-wave resonance of the individual scatterers. A new s-wave resonance of the pair also appears. The relation of these proximity resonances (so called because they appear when the scatterers are close together) to the Thomas and Efimov effects is discussed. copyright 1996 The American Physical Society

  13. Proximity friction reexamined

    International Nuclear Information System (INIS)

    Krappe, H.J.

    1989-01-01

    The contribution of inelastic excitations to radial and tangential friction form-factors in heavy-ion collisions is investigated in the frame-work of perturbation theory. The dependence of the form factors on the essential geometrical and level-density parameters of the scattering system is exhibited in a rather closed form. The conditions for the existence of time-local friction coefficients are discussed. Results are compared to form factors from other models, in particular the transfer-related proximity friction. For the radial friction coefficient the inelastic excitation mechanism seems to be the dominant contribution in peripheral collisions. (orig.)

  14. Proximal femoral fractures.

    Science.gov (United States)

    Webb, Lawrence X

    2002-01-01

    Fractures of the proximal femur include fractures of the head, neck, intertrochanteric, and subtrochanteric regions. Head fractures commonly accompany dislocations. Neck fractures and intertrochanteric fractures occur with greatest frequency in elderly patients with a low bone mineral density and are produced by low-energy mechanisms. Subtrochanteric fractures occur in a predominantly strong cortical osseous region which is exposed to large compressive stresses. Implants used to address these fractures must be able to accommodate significant loads while the fractures consolidate. Complications secondary to these injuries produce significant morbidity and include infection, nonunion, malunion, decubitus ulcers, fat emboli, deep venous thrombosis, pulmonary embolus, pneumonia, myocardial infarction, stroke, and death.

  15. Echosonography with proximity sensors

    International Nuclear Information System (INIS)

    Thaisiam, W; Laithong, T; Meekhun, S; Chaiwathyothin, N; Thanlarp, P; Danworaphong, S

    2013-01-01

    We propose the use of a commercial ultrasonic proximity sensor kit for profiling an altitude-varying surface by employing echosonography. The proximity sensor kit, two identical transducers together with its dedicated operating circuit, is used as a profiler for the construction of an image. Ultrasonic pulses are emitted from one of the transducers and received by the other. The time duration between the pulses allows us to determine the traveling distance of each pulse. In the experiment, the circuit is used with the addition of two copper wires for directing the outgoing and incoming signals to an oscilloscope. The time of flight of ultrasonic pulses can thus be determined. Square grids of 5 × 5 cm 2 are made from fishing lines, forming pixels in the image. The grids are designed to hold the detection unit in place, about 30 cm above a flat surface. The surface to be imaged is constructed to be height varying and placed on the flat surface underneath the grids. Our result shows that an image of the profiled surface can be created by varying the location of the detection unit along the grid. We also investigate the deviation in relation to the time of flight of the ultrasonic pulse. Such an experiment should be valuable for conveying the concept of ultrasonic imaging to physical and medical science undergraduate students. Due to its simplicity, the setup could be made in any undergraduate laboratory relatively inexpensively and it requires no complex parts. The results illustrate the concept of echosonography. (paper)

  16. Children's proximal societal conditions

    DEFF Research Database (Denmark)

    Stanek, Anja Hvidtfeldt

    2018-01-01

    that is above or outside the institutional setting or the children’s everyday life, but something that is represented through societal structures and actual persons participating (in political ways) within the institutional settings, in ways that has meaning to children’s possibilities to participate, learn...... and develop. Understanding school or kindergarten as (part of) the children’s proximal societal conditions for development and learning, means for instance that considerations about an inclusive agenda are no longer simply thoughts about the school – for economic reasons – having space for as many pupils...... as possible (schools for all). Such thoughts can be supplemented by reflections about which version of ‘the societal’ we wish to present our children with, and which version of ‘the societal’ we wish to set up as the condition for children’s participation and development. The point is to clarify or sharpen...

  17. Proximity detection system underground

    Energy Technology Data Exchange (ETDEWEB)

    Denis Kent [Mine Site Technologies (Australia)

    2008-04-15

    Mine Site Technologies (MST) with the support ACARP and Xstrata Coal NSW, as well as assistance from Centennial Coal, has developed a Proximity Detection System to proof of concept stage as per plan. The basic aim of the project was to develop a system to reduce the risk of the people coming into contact with vehicles in an uncontrolled manner (i.e. being 'run over'). The potential to extend the developed technology into other areas, such as controls for vehicle-vehicle collisions and restricting access of vehicle or people into certain zones (e.g. non FLP vehicles into Hazardous Zones/ERZ) was also assessed. The project leveraged off MST's existing Intellectual Property and experience gained with our ImPact TRACKER tagging technology, allowing the development to be fast tracked. The basic concept developed uses active RFID Tags worn by miners underground to be detected by vehicle mounted Readers. These Readers in turn provide outputs that can be used to alert a driver (e.g. by light and/or audible alarm) that a person (Tag) approaching within their vicinity. The prototype/test kit developed proved the concept and technology, the four main components being: Active RFID Tags to send out signals for detection by vehicle mounted receivers; Receiver electronics to detect RFID Tags approaching within the vicinity of the unit to create a long range detection system (60 m to 120 m); A transmitting/exciter device to enable inner detection zone (within 5 m to 20 m); and A software/hardware device to process & log incoming Tags reads and create certain outputs. Tests undertaken in the laboratory and at a number of mine sites, confirmed the technology path taken could form the basis of a reliable Proximity Detection/Alert System.

  18. PROXIMITY MANAGEMENT IN CRISIS CONDITIONS

    Directory of Open Access Journals (Sweden)

    Ion Dorin BUMBENECI

    2010-01-01

    Full Text Available The purpose of this study is to evaluate the level of assimilation for the terms "Proximity Management" and "Proximity Manager", both in the specialized literature and in practice. The study has two parts: the theoretical research of the two terms, and an evaluation of the use of Proximity management in 32 companies in Gorj, Romania. The object of the evaluation resides in 27 companies with less than 50 employees and 5 companies with more than 50 employees.

  19. ProxImaL: efficient image optimization using proximal algorithms

    KAUST Repository

    Heide, Felix; Diamond, Steven; Nieß ner, Matthias; Ragan-Kelley, Jonathan; Heidrich, Wolfgang; Wetzstein, Gordon

    2016-01-01

    domain-specific language and compiler for image optimization problems that makes it easy to experiment with different problem formulations and algorithm choices. The language uses proximal operators as the fundamental building blocks of a variety

  20. A proximal point algorithm with generalized proximal distances to BEPs

    OpenAIRE

    Bento, G. C.; Neto, J. X. Cruz; Lopes, J. O.; Soares Jr, P. A.; Soubeyran, A.

    2014-01-01

    We consider a bilevel problem involving two monotone equilibrium bifunctions and we show that this problem can be solved by a proximal point method with generalized proximal distances. We propose a framework for the convergence analysis of the sequences generated by the algorithm. This class of problems is very interesting because it covers mathematical programs and optimization problems under equilibrium constraints. As an application, we consider the problem of the stability and change dyna...

  1. Fractures of the proximal humerus

    DEFF Research Database (Denmark)

    Brorson, Stig

    2013-01-01

    Fractures of the proximal humerus have been diagnosed and managed since the earliest known surgical texts. For more than four millennia the preferred treatment was forceful traction, closed reduction, and immobilization with linen soaked in combinations of oil, honey, alum, wine, or cerate......, classification of proximal humeral fractures remains a challenge for the conduct, reporting, and interpretation of clinical trials. The evidence for the benefits of surgery in complex fractures of the proximal humerus is weak. In three systematic reviews I studied the outcome after locking plate osteosynthesis...

  2. A novel -192c/g mutation in the proximal P2 promoter of the hepatocyte nuclear factor-4 alpha gene (HNF4A) associates with late-onset diabetes

    DEFF Research Database (Denmark)

    Ek, Jakob; Hansen, Sara P; Lajer, Maria

    2006-01-01

    Recently, it has been shown that mutations in the P2 promoter of the hepatocyte nuclear factor (HNF)-4 alpha gene (HNF4A) cause maturity-onset diabetes of the young (MODY), while single nucleotide polymorphisms in this locus are associated with type 2 diabetes. In this study, we examined 1,189 bp...... of the P2 promoter and the associated exon 1D of HNF4A for variations associated with diabetes in 114 patients with type 2 diabetes, 72 MODYX probands, and 85 women with previous gestational diabetes mellitus. A -192c/g mutation was found in five patients. We screened 1,587 diabetic subjects and 4......,812 glucose-tolerant subjects for the -192c/g mutation and identified 5 diabetic and 1 glucose-tolerant mutation carriers (P=0.004). Examination of the families showed that carriers of the -192c/g mutation had a significantly impaired glucose-stimulated insulin release and lower levels of serum total...

  3. Preliminary study on leadership proximity

    Directory of Open Access Journals (Sweden)

    Ghinea Valentina Mihaela

    2017-07-01

    Full Text Available In general, it is agreed that effective leadership requires a certain degree of proximity, either physical or mental, which enables leaders to maintain control over their followers and communicate their vision. Although we agree with the leadership proximity principles which states that leaders are able to efficiently serve only those people with whom they interact frequently, in this article we focus instead on the disadvantages of being too close and the way in which close proximity can actually hurt the effectiveness of leadership. The main effects that we discuss regard the way in which proximity and familiarity allow followers to see the weaknesses and faults of the leader much more easily and thus diminish the leader’s heroic aura, and the emotional bias that results from a leader being too familiar with his followers which will impede the process of rational decision making. As a result, we argue that there exists a functional proximity which allows the leader the necessary space in which to perform effective identity work and to hide the backstage aspects of leadership, while also allowing him an emotional buffer zone which will enable him to maintain the ability to see clearly and make rational decisions.

  4. Decreased expression of lysyl hydroxylase 2 (LH2) in skin fibroblasts from three Ehlers-Danlos patients does not result from mutations in either the coding or proximal promoter region of the LH2 gene.

    Science.gov (United States)

    Walker, L C; Teebi, A S; Marini, J C; De Paepe, A; Malfait, F; Atsawasuwan, P; Yamauchi, M; Yeowell, H N

    2004-12-01

    The Ehlers-Danlos syndromes (EDS) are a heterogeneous group of inherited connective tissue disorders characterized by tissue fragility, hyperelasticity of the skin and joint hypermobility. This phenotype, accompanied by kyphoscoliosis and/or ocular fragility, is present in patients with the autosomal recessive type VI form of EDS. These patients have significantly decreased levels of lysyl hydroxylase (LH) activity, due to mutations in the LH1 gene. LH hydroxylates specific lysine residues in the collagen molecule that are precursors for the formation of cross-links which provide collagen with its tensile strength. No disorder has been directly linked to decreased expression of LH2 and LH3, two other isoforms of LH. This study describes 3 patients with mixed phenotypes of EDS, who have significantly decreased mRNAs for LH2, but normal levels of LH1 and LH3 mRNAs, in their skin fibroblasts. In contrast to the effect of LH1 deficiency in EDS VI patients, the decreased expression of LH2 does not affect LH activity, bifunctional collagen cross-links (measured after reduction as dihydroxylysinonorleucine (DHLNL) and hydroxylysinonorleucine (HLNL)), or helical lysine hydroxylation in these cell lines. Sequence analysis of full length LH2 cDNAs and 1kb of the promoter region of LH2 does not show mutations that could explain the decreased expression of LH2. These results suggest that the deficiency of LH2 in these fibroblasts may be caused by changes in other factors required for the expression of LH2.

  5. The sooner, the better: exercise outcome proximity and intrinsic motivation.

    Science.gov (United States)

    Evans, M Blair; Cooke, Lisa M; Murray, Robyn A; Wilson, Anne E

    2014-11-01

    Despite evidence that outcomes are highly valued when they are expected sooner rather than further into the future (Ainslie, 1975), limited research effort has been devoted to understanding the role of exercise outcome proximity. The purpose of this study was to examine how temporal proximity to positive outcomes influences exercisers' intrinsic motivation. We expected that focusing people on temporally proximal exercise outcomes would increase intrinsic motivation, especially among low-frequency exercisers. This online experimental study was completed by 135 community exercisers (Mage  = 31.11, SD = 10.29; 62% female) who reported an average of 4.86 exercise bouts per week (SD = 2.12). Participants were randomly assigned to a condition that primed temporally proximal positive exercise outcomes (i.e. experienced during or directly following an exercise bout) or temporally distal outcomes (i.e. experienced after days, months, or years of regular exercise). Participants then reported perceptions of behavioral regulation in exercise. As expected, the proximal exercise outcome condition elicited increased intrinsic regulation among those participants who exercised less frequently (i.e. 1 SD below the mean). This study reveals the importance of considering proximity as an important dimension of exercise outcomes-particularly when promoting intrinsic motivation among relatively infrequent exercisers. © 2014 The International Association of Applied Psychology.

  6. ProxImaL: efficient image optimization using proximal algorithms

    KAUST Repository

    Heide, Felix

    2016-07-11

    Computational photography systems are becoming increasingly diverse, while computational resources-for example on mobile platforms-are rapidly increasing. As diverse as these camera systems may be, slightly different variants of the underlying image processing tasks, such as demosaicking, deconvolution, denoising, inpainting, image fusion, and alignment, are shared between all of these systems. Formal optimization methods have recently been demonstrated to achieve state-of-the-art quality for many of these applications. Unfortunately, different combinations of natural image priors and optimization algorithms may be optimal for different problems, and implementing and testing each combination is currently a time-consuming and error-prone process. ProxImaL is a domain-specific language and compiler for image optimization problems that makes it easy to experiment with different problem formulations and algorithm choices. The language uses proximal operators as the fundamental building blocks of a variety of linear and nonlinear image formation models and cost functions, advanced image priors, and noise models. The compiler intelligently chooses the best way to translate a problem formulation and choice of optimization algorithm into an efficient solver implementation. In applications to the image processing pipeline, deconvolution in the presence of Poisson-distributed shot noise, and burst denoising, we show that a few lines of ProxImaL code can generate highly efficient solvers that achieve state-of-the-art results. We also show applications to the nonlinear and nonconvex problem of phase retrieval.

  7. Symmetry-based reciprocity: evolutionary constraints on a proximate mechanism.

    Science.gov (United States)

    Campennì, Marco; Schino, Gabriele

    2016-01-01

    Background. While the evolution of reciprocal cooperation has attracted an enormous attention, the proximate mechanisms underlying the ability of animals to cooperate reciprocally are comparatively neglected. Symmetry-based reciprocity is a hypothetical proximate mechanism that has been suggested to be widespread among cognitively unsophisticated animals. Methods. We developed two agent-based models of symmetry-based reciprocity (one relying on an arbitrary tag and the other on interindividual proximity) and tested their ability both to reproduce significant emergent features of cooperation in group living animals and to promote the evolution of cooperation. Results. Populations formed by agents adopting symmetry-based reciprocity showed differentiated "social relationships" and a positive correlation between cooperation given and received: two common aspects of animal cooperation. However, when reproduction and selection across multiple generations were added to the models, agents adopting symmetry-based reciprocity were outcompeted by selfish agents that never cooperated. Discussion. In order to evolve, hypothetical proximate mechanisms must be able to stand competition from alternative strategies. While the results of our simulations require confirmation using analytical methods, we provisionally suggest symmetry-based reciprocity is to be abandoned as a possible proximate mechanism underlying the ability of animals to reciprocate cooperative interactions.

  8. Electromagnetic properties of proximity systems

    Science.gov (United States)

    Kresin, Vladimir Z.

    1985-07-01

    Magnetic screening in the proximity system Sα-Mβ, where Mβ is a normal metal N, semiconductor (semimetal), or a superconductor, is studied. Main attention is paid to the low-temperature region where nonlocality plays an important role. The thermodynamic Green's-function method is employed in order to describe the behavior of the proximity system in an external field. The temperature and thickness dependences of the penetration depth λ are obtained. The dependence λ(T) differs in a striking way from the dependence in usual superconductors. The strong-coupling effect is taken into account. A special case of screening in a superconducting film backed by a size-quantizing semimetal film is considered. The results obtained are in good agreement with experimental data.

  9. Electromagnetic properties of proximity systems

    International Nuclear Information System (INIS)

    Kresin, V.Z.

    1985-01-01

    Magnetic screening in the proximity system S/sub α/-M/sub β/, where M/sub β/ is a normal metal N, semiconductor (semimetal), or a superconductor, is studied. Main attention is paid to the low-temperature region where nonlocality plays an important role. The thermodynamic Green's-function method is employed in order to describe the behavior of the proximity system in an external field. The temperature and thickness dependences of the penetration depth lambda are obtained. The dependence lambda(T) differs in a striking way from the dependence in usual superconductors. The strong-coupling effect is taken into account. A special case of screening in a superconducting film backed by a size-quantizing semimetal film is considered. The results obtained are in good agreement with experimental data

  10. Proximity effect at Millikelvin temperatures

    International Nuclear Information System (INIS)

    Mota, A.C.

    1986-01-01

    Proximity effects have been studied extensively for the past 25 years. Typically, they are in films several thousand angstroms thick at temperatures not so far below T/sub CNS/, the transition temperature of the NS system. Interesting is, however, the proximity effect at temperatures much lower than T/sub CNS/. In this case, the Cooper-pair amplitudes are not small and very long pair penetration lengths into the normal metal can be expected. Thus, we have observed pair penetration lengths. For these investigations very suitable specimens are commercial wires of one filament of NbTi or Nb embedded in a copper matrix. The reasons are the high transmission coefficient at the interface between the copper and the superconductor and the fact that the copper in these commercial wires is rather clean with electron free paths between 5 to 10 μm long. In this paper, the magnetic properties of thick proximity systems in the range of temperatures between T/sub CNS/ and 5 x 10/sup -4/ T/sub CNS/ in both low and high magnetic fields are discussed

  11. Omeprazole promotes proximal duodenal mucosal bicarbonate secretion in humans

    DEFF Research Database (Denmark)

    Mertz-Nielsen, Anette; Hillingsø, J; Bukhave, Klaus

    1996-01-01

    this incidental finding is explained by more potent gastric acid inhibition by omeprazole or might be caused by the different mode of drug action. Basal and stimulated gastric and duodenal bicarbonate secretion rates were measured in the same subjects in control experiments (n=17) and after pretreatment with high......H 6.9 v 6.8; p>0.05). Omeprazole caused higher rates of basal (mean (SEM)) (597 (48) v 351 (39) mu mol/h; pstimulated (834 (72) v 474 (66) mu mol/h; pstimulated (3351 (678) v 2550 (456) mu mol/h; p>0.05) duodenal bicarbonate secretion compared with control...... experiments. Also the combination of omeprazole and ranitidine increased (p=0.05) duodenal bicarbonate secretion, while ranitidine alone caused no change in either basal or stimulated secretion. In the stomach basal as well as vagally stimulated bicarbonate secretion was independent of the means of acid...

  12. Omeprazole promotes proximal duodenal mucosal bicarbonate secretion in humans

    DEFF Research Database (Denmark)

    Mertz-Nielsen, A; Hillingsø, Jens; Bukhave, K

    1996-01-01

    with control experiments. Also the combination of omeprazole and ranitidine increased (p = 0.05) duodenal bicarbonate secretion, while ranitidine alone caused no change in either basal or stimulated secretion. In the stomach basal as well as vagally stimulated bicarbonate secretion was independent of the means...

  13. Equilibrium properties of proximity effect

    International Nuclear Information System (INIS)

    Esteve, D.; Pothier, H.; Gueron, S.; Birge, N.O.; Devoret, M.

    1996-01-01

    The proximity effect in diffusive normal-superconducting (NS) nano-structures is described by the Usadel equations for the electron pair correlations. We show that these equations obey a variational principle with a potential which generalizes the Ginzburg-Landau energy functional. We discuss simple examples of NS circuits using this formalism. In order to test the theoretical predictions of the Usadel equations, we have measured the density of states as a function of energy on a long N wire in contact with a S wire at one end, at different distances from the NS interface. (authors)

  14. Equilibrium properties of proximity effect

    Energy Technology Data Exchange (ETDEWEB)

    Esteve, D.; Pothier, H.; Gueron, S.; Birge, N.O.; Devoret, M.

    1996-12-31

    The proximity effect in diffusive normal-superconducting (NS) nano-structures is described by the Usadel equations for the electron pair correlations. We show that these equations obey a variational principle with a potential which generalizes the Ginzburg-Landau energy functional. We discuss simple examples of NS circuits using this formalism. In order to test the theoretical predictions of the Usadel equations, we have measured the density of states as a function of energy on a long N wire in contact with a S wire at one end, at different distances from the NS interface. (authors). 12 refs.

  15. E4orf1 Enhances Glucose Uptake Independent of Proximal Insulin Signaling.

    Science.gov (United States)

    Na, Ha-Na; Hegde, Vijay; Dubuisson, Olga; Dhurandhar, Nikhil V

    2016-01-01

    Impaired proximal insulin signaling is often present in diabetes. Hence, approaches to enhance glucose disposal independent of proximal insulin signaling are desirable. Evidence indicates that Adenovirus-derived E4orf1 protein may offer such an approach. This study determined if E4orf1 improves insulin sensitivity and downregulates proximal insulin signaling in vivo and enhances cellular glucose uptake independent of proximal insulin signaling in vitro. High fat fed mice were injected with a retrovirus plasmid expressing E4orf1, or a null vector. E4orf1 significantly improved insulin sensitivity in response to a glucose load. Yet, their proximal insulin signaling in fat depots was impaired, as indicated by reduced tyrosine phosphorylation of insulin receptor (IR), and significantly increased abundance of ectonucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1). In 3T3-L1 pre-adipocytes E4orf1 expression impaired proximal insulin signaling. Whereas, treatment with rosiglitazone reduced ENPP1 abundance. Unaffected by IR-KD (insulin receptor knockdown) with siRNA, E4orf1 significantly up-regulated distal insulin signaling pathway and enhanced cellular glucose uptake. In vivo, E4orf1 impairs proximal insulin signaling in fat depots yet improves glycemic control. This is probably explained by the ability of E4orf1 to promote cellular glucose uptake independent of proximal insulin signaling. E4orf1 may provide a therapeutic template to enhance glucose disposal in the presence of impaired proximal insulin signaling.

  16. E4orf1 Enhances Glucose Uptake Independent of Proximal Insulin Signaling.

    Directory of Open Access Journals (Sweden)

    Ha-Na Na

    Full Text Available Impaired proximal insulin signaling is often present in diabetes. Hence, approaches to enhance glucose disposal independent of proximal insulin signaling are desirable. Evidence indicates that Adenovirus-derived E4orf1 protein may offer such an approach. This study determined if E4orf1 improves insulin sensitivity and downregulates proximal insulin signaling in vivo and enhances cellular glucose uptake independent of proximal insulin signaling in vitro. High fat fed mice were injected with a retrovirus plasmid expressing E4orf1, or a null vector. E4orf1 significantly improved insulin sensitivity in response to a glucose load. Yet, their proximal insulin signaling in fat depots was impaired, as indicated by reduced tyrosine phosphorylation of insulin receptor (IR, and significantly increased abundance of ectonucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1. In 3T3-L1 pre-adipocytes E4orf1 expression impaired proximal insulin signaling. Whereas, treatment with rosiglitazone reduced ENPP1 abundance. Unaffected by IR-KD (insulin receptor knockdown with siRNA, E4orf1 significantly up-regulated distal insulin signaling pathway and enhanced cellular glucose uptake. In vivo, E4orf1 impairs proximal insulin signaling in fat depots yet improves glycemic control. This is probably explained by the ability of E4orf1 to promote cellular glucose uptake independent of proximal insulin signaling. E4orf1 may provide a therapeutic template to enhance glucose disposal in the presence of impaired proximal insulin signaling.

  17. Realities of proximity facility siting

    International Nuclear Information System (INIS)

    DeMott, D.L.

    1981-01-01

    Numerous commercial nuclear power plant sites have 2 to 3 reactors located together, and a group of Facilities with capabilities for fuel fabrication, a nuclear reactor, a storage area for spent fuel, and a maintenance area for contaminated equipment and radioactive waste storage are being designed and constructed in the US. The proximity of these facilities to each other provides that the ordinary flow of materials remain within a limited area. Interactions between the various facilities include shared resources such as communication, fire protection, security, medical services, transportation, water, electrical, personnel, emergency planning, transport of hazardous material between facilities, and common safety and radiological requirements between facilities. This paper will explore the advantages and disadvantages of multiple facilities at one site. Problem areas are identified, and recommendations for planning and coordination are discussed

  18. comparative proximate composition and antioxidant vitamins

    African Journals Online (AJOL)

    DR. AMINU

    Keywords: Comparative, proximate composition, antioxidant vitamins, honey. INTRODUCTION ... solution of inverted sugars and complex mixture of other saccharides ... enzymatic browning in apple slices and grape juice. (Khan, 1985).

  19. Proximate, Mineral and Phytochemical Composition of Dioscorea ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Keywords: Dioscorea dumetorum, proximate composition, mineral analysis, phytochemical screening ... were analyzed using atomic absorption ... determined using a Hack Dr/200 Spectrophotometer. ... Lead Acetate. +. +. + .... cosmetics.

  20. Proximate composition and antinutrient content of pumpkin ...

    African Journals Online (AJOL)

    Proximate composition and antinutrient content of pumpkin ( Cucurbita pepo ) and sorghum ( Sorghum bicolor ) flour blends fermented with Lactobacillus plantarum , Aspergillus niger and Bacillus subtilis.

  1. ATM promotes the obligate XY crossover and both crossover control and chromosome axis integrity on autosomes.

    Directory of Open Access Journals (Sweden)

    Marco Barchi

    2008-05-01

    Full Text Available During meiosis in most sexually reproducing organisms, recombination forms crossovers between homologous maternal and paternal chromosomes and thereby promotes proper chromosome segregation at the first meiotic division. The number and distribution of crossovers are tightly controlled, but the factors that contribute to this control are poorly understood in most organisms, including mammals. Here we provide evidence that the ATM kinase or protein is essential for proper crossover formation in mouse spermatocytes. ATM deficiency causes multiple phenotypes in humans and mice, including gonadal atrophy. Mouse Atm-/- spermatocytes undergo apoptosis at mid-prophase of meiosis I, but Atm(-/- meiotic phenotypes are partially rescued by Spo11 heterozygosity, such that ATM-deficient spermatocytes progress to meiotic metaphase I. Strikingly, Spo11+/-Atm-/- spermatocytes are defective in forming the obligate crossover on the sex chromosomes, even though the XY pair is usually incorporated in a sex body and is transcriptionally inactivated as in normal spermatocytes. The XY crossover defect correlates with the appearance of lagging chromosomes at metaphase I, which may trigger the extensive metaphase apoptosis that is observed in these cells. In addition, control of the number and distribution of crossovers on autosomes appears to be defective in the absence of ATM because there is an increase in the total number of MLH1 foci, which mark the sites of eventual crossover formation, and because interference between MLH1 foci is perturbed. The axes of autosomes exhibit structural defects that correlate with the positions of ongoing recombination. Together, these findings indicate that ATM plays a role in both crossover control and chromosome axis integrity and further suggests that ATM is important for coordinating these features of meiotic chromosome dynamics.

  2. DNA Mismatch Repair Deficiency Promotes Genomic Instability in a Subset of Papillary Thyroid Cancers.

    Science.gov (United States)

    Javid, Mahsa; Sasanakietkul, Thanyawat; Nicolson, Norman G; Gibson, Courtney E; Callender, Glenda G; Korah, Reju; Carling, Tobias

    2018-02-01

    Efficient DNA damage repair by MutL-homolog DNA mismatch repair (MMR) enzymes, MLH1, MLH3, PMS1 and PMS2, are required to maintain thyrocyte genomic integrity. We hypothesized that persistent oxidative stress and consequent transcriptional dysregulation observed in thyroid follicles will lead to MMR deficiency and potentiate papillary thyroid tumorigenesis. MMR gene expression was analyzed by targeted microarray in 18 papillary thyroid cancer (PTC), 9 paracarcinoma normal thyroid (PCNT) and 10 normal thyroid (NT) samples. The findings were validated by qRT-PCR, and in follicular thyroid cancers (FTC) and follicular thyroid adenomas (FTA) for comparison. FOXO transcription factor expression was also analyzed. Protein expression was assessed by immunohistochemistry. Genomic integrity was evaluated by whole-exome sequencing-derived read-depth analysis and Mann-Whitney U test. Clinical correlations were assessed using Fisher's exact and t tests. Microarray and qRT-PCR revealed reduced expression of all four MMR genes in PTC compared with PCNT and of PMS2 compared with NT. FTC and FTA showed upregulation in MLH1, MLH3 and PMS2. PMS2 protein expression correlated with the mRNA expression pattern. FOXO1 showed lower expression in PMS2-deficient PTCs (log2-fold change -1.72 vs. -0.55, U = 11, p clinical characteristics. MMR deficiency, potentially promoted by FOXO1 suppression, may explain the etiology for PTC development in some patients. FTC and FTA retain MMR activity and are likely caused by a different tumorigenic pathway.

  3. Transverse and Longitudinal proximity effect

    Science.gov (United States)

    Jalan, Pryianka; Chand, Hum; Srianand, Raghunathan

    2018-04-01

    With close pairs (˜1.5arcmin) of quasars (QSOs), absorption in the spectra of a background quasar in the vicinity of a foreground quasar can be used to study the environment of the latter quasar at kpc-Mpc scales. For this we used a sample of 205 quasar pairs from the Sloan Digital Sky-Survey Data Release 12 (SDSS DR12) in the redshift range of 2.5 to 3.5 by studying their H I Ly-α absorption. We study the environment of QSOs both in the longitudinal as well as in the transverse direction by carrying out a statistical comparison of the Ly-α absorption lines in the quasar vicinity to that of the absorption lines caused by the inter-galactic medium (IGM). This comparison was done with IGM, matched in absorption redshift and signal-to-noise ratio (SNR) to that of the proximity region. In contrast to the measurements along the line-of-sight, the regions transverse to the quasars exhibit enhanced H I Ly-α absorption. This discrepancy can either be interpreted as due to an anisotropic emission from the quasars or as a consequence of their finite lifetime.

  4. Proximal Participation: A Pathway into Work

    Science.gov (United States)

    Chan, Selena

    2013-01-01

    In a longitudinal case study of apprentices, the term proximal participation was coined to describe the entry process of young people, with unclear career destinations, into the trade of baking. This article unravels the significance of proximal participation in the decision-making processes of young people who enter a trade through initial…

  5. Bimalleolar ankle fracture with proximal fibular fracture

    NARCIS (Netherlands)

    Colenbrander, R. J.; Struijs, P. A. A.; Ultee, J. M.

    2005-01-01

    A 56-year-old female patient suffered a bimalleolar ankle fracture with an additional proximal fibular fracture. This is an unusual fracture type, seldom reported in literature. It was operatively treated by open reduction and internal fixation of the lateral malleolar fracture. The proximal fibular

  6. Proximal Alternating Direction Method with Relaxed Proximal Parameters for the Least Squares Covariance Adjustment Problem

    Directory of Open Access Journals (Sweden)

    Minghua Xu

    2014-01-01

    Full Text Available We consider the problem of seeking a symmetric positive semidefinite matrix in a closed convex set to approximate a given matrix. This problem may arise in several areas of numerical linear algebra or come from finance industry or statistics and thus has many applications. For solving this class of matrix optimization problems, many methods have been proposed in the literature. The proximal alternating direction method is one of those methods which can be easily applied to solve these matrix optimization problems. Generally, the proximal parameters of the proximal alternating direction method are greater than zero. In this paper, we conclude that the restriction on the proximal parameters can be relaxed for solving this kind of matrix optimization problems. Numerical experiments also show that the proximal alternating direction method with the relaxed proximal parameters is convergent and generally has a better performance than the classical proximal alternating direction method.

  7. Proximal Hamstring Tendinosis and Partial Ruptures.

    Science.gov (United States)

    Startzman, Ashley N; Fowler, Oliver; Carreira, Dominic

    2017-07-01

    Proximal hamstring tendinosis and partial hamstring origin ruptures are painful conditions of the proximal thigh and hip that may occur in the acute, chronic, or acute on chronic setting. Few publications exist related to their diagnosis and management. This systematic review discusses the incidence, treatment, and prognosis of proximal hamstring tendinosis and partial hamstring ruptures. Conservative treatment measures include nonsteroidal anti-inflammatory drugs, physical therapy, rest, and ice. If these measures fail, platelet-rich plasma or shockwave therapy may be considered. When refractory to conservative management, these injuries may be treated with surgical debridement and hamstring reattachment. [Orthopedics. 2017; 40(4):e574-e582.]. Copyright 2017, SLACK Incorporated.

  8. THE PROXIMATE COMPOSITION OF AFRICAN BUSH MANGO ...

    African Journals Online (AJOL)

    BIG TIMMY

    Information regarding previous studies on these physico-chemical ... This behaviour may be attributed to its high myristic acid ... The authors express deep appreciation to the. Heads of ... of a typical rural processing method on the proximate ...

  9. Proximate composition and nutritional characterization of Chia ...

    African Journals Online (AJOL)

    ... dairy product associated with several beneficial nutritional and health effects. ... The results for amino acids showed that the essential and non-essential amino ... proximate composition and nutritional (amino acids, fatty acids, and minerals ...

  10. Proximal focal femoral deficiency: A case report

    Directory of Open Access Journals (Sweden)

    Shashank Sharma

    2015-01-01

    Full Text Available Proximal focal femoral deficiency (PFFD is a rare congenital anomaly resulting in limb shortening and disability in young. The exact cause of the disease is not known and it may present as varying grades of affection involving the proximal femur and the acetabulum. Recognition of this rare abnormality on radiographs can help manage these cases better since early institution of therapy may help in achieving adequate growth of the femur.

  11. Proximity sensor system development. CRADA final report

    International Nuclear Information System (INIS)

    Haley, D.C.; Pigoski, T.M.

    1998-01-01

    Lockheed Martin Energy Research Corporation (LMERC) and Merritt Systems, Inc. (MSI) entered into a Cooperative Research and Development Agreement (CRADA) for the development and demonstration of a compact, modular proximity sensing system suitable for application to a wide class of manipulator systems operated in support of environmental restoration and waste management activities. In teleoperated modes, proximity sensing provides the manipulator operator continuous information regarding the proximity of the manipulator to objects in the workspace. In teleoperated and robotic modes, proximity sensing provides added safety through the implementation of active whole arm collision avoidance capabilities. Oak Ridge National Laboratory (ORNL), managed by LMERC for the United States Department of Energy (DOE), has developed an application specific integrated circuit (ASIC) design for the electronics required to support a modular whole arm proximity sensing system based on the use of capacitive sensors developed at Sandia National Laboratories. The use of ASIC technology greatly reduces the size of the electronics required to support the selected sensor types allowing deployment of many small sensor nodes over a large area of the manipulator surface to provide maximum sensor coverage. The ASIC design also provides a communication interface to support sensor commands from and sensor data transmission to a distributed processing system which allows modular implementation and operation of the sensor system. MSI is a commercial small business specializing in proximity sensing systems based upon infrared and acoustic sensors

  12. Proximity sensor system development. CRADA final report

    Energy Technology Data Exchange (ETDEWEB)

    Haley, D.C. [Oak Ridge National Lab., TN (United States); Pigoski, T.M. [Merrit Systems, Inc. (United States)

    1998-01-01

    Lockheed Martin Energy Research Corporation (LMERC) and Merritt Systems, Inc. (MSI) entered into a Cooperative Research and Development Agreement (CRADA) for the development and demonstration of a compact, modular proximity sensing system suitable for application to a wide class of manipulator systems operated in support of environmental restoration and waste management activities. In teleoperated modes, proximity sensing provides the manipulator operator continuous information regarding the proximity of the manipulator to objects in the workspace. In teleoperated and robotic modes, proximity sensing provides added safety through the implementation of active whole arm collision avoidance capabilities. Oak Ridge National Laboratory (ORNL), managed by LMERC for the United States Department of Energy (DOE), has developed an application specific integrated circuit (ASIC) design for the electronics required to support a modular whole arm proximity sensing system based on the use of capacitive sensors developed at Sandia National Laboratories. The use of ASIC technology greatly reduces the size of the electronics required to support the selected sensor types allowing deployment of many small sensor nodes over a large area of the manipulator surface to provide maximum sensor coverage. The ASIC design also provides a communication interface to support sensor commands from and sensor data transmission to a distributed processing system which allows modular implementation and operation of the sensor system. MSI is a commercial small business specializing in proximity sensing systems based upon infrared and acoustic sensors.

  13. Adult and Child Development in the Zone of Proximal Development: Socratic Dialogue in a Playworld

    Science.gov (United States)

    Ferholt, Beth; Lecusay, Robert

    2010-01-01

    This article analyses adult and child development in the zone of proximal development in an educational practice based in Vygotsky's theories of play: the playworld educational practice. The playworld educational practice is a central component of a Scandinavian play pedagogy that promotes shared responsibility amongst adults and children for…

  14. Locking plate fixation for proximal humerus fractures.

    LENUS (Irish Health Repository)

    Burke, Neil G

    2012-02-01

    Locking plates are increasingly used to surgically treat proximal humerus fractures. Knowledge of the bone quality of the proximal humerus is important. Studies have shown the medial and dorsal aspects of the proximal humeral head to have the highest bone strength, and this should be exploited by fixation techniques, particularly in elderly patients with osteoporosis. The goals of surgery for proximal humeral fractures should involve minimal soft tissue dissection and achieve anatomic reduction of the head complex with sufficient stability to allow for early shoulder mobilization. This article reviews various treatment options, in particular locking plate fixation. Locking plate fixation is associated with a high complication rate, such as avascular necrosis (7.9%), screw cutout (11.6%), and revision surgery (13.7%). These complications are frequently due to the varus deformation of the humeral head. Strategic screw placement in the humeral head would minimize the possibility of loss of fracture reduction and potential hardware complications. Locking plate fixation is a good surgical option for the management of proximal humerus fractures. Complications can be avoided by using better bone stock and by careful screw placement in the humeral head.

  15. Giant proximity effect in ferromagnetic bilayers

    Science.gov (United States)

    Ramos, Silvia; Charlton, Tim; Quintanilla, Jorge; Suter, Andreas; Moodera, Jagadeesh; Prokscha, Thomas; Salman, Zaher; Forgan, Ted

    2013-03-01

    The proximity effect is a phenomenon where an ordered state leaks from a material into an adjacent one over some finite distance, ξ. For superconductors, this distance is ~ the coherence length. Nevertheless much longer-range, ``giant'' proximity effects have been observed in cuprate junctions. This surprising effect can be understood as a consequence of critical opalescence. Since this occurs near all second order phase transitions, giant proximity effects should be very general and, in particular, they should be present in magnetic systems. The ferromagnetic proximity effect has the advantage that its order parameter (magnetization) can be observed directly. We investigate the above phenomenon in Co/EuS bilayer films, where both materials undergo ferromagnetic transitions but at rather different temperatures (bulk TC of 1400K for Co and 16.6K for EuS). A dramatic increase in the range of the proximity effect is expected near the TC of EuS. We present the results of our measurements of the magnetization profiles as a function of temperature, carried out using the complementary techniques of low energy muon rotation and polarized neutron reflectivity. Work supported by EPSRC, STFC and ONR grant N00014-09-1-0177 and NSF grant DMR 0504158.

  16. Proximity operations concept design study, task 6

    Science.gov (United States)

    Williams, A. N.

    1990-01-01

    The feasibility of using optical technology to perform the mission of the proximity operations communications subsystem on Space Station Freedom was determined. Proximity operations mission requirements are determined and the relationship to the overall operational environment of the space station is defined. From this information, the design requirements of the communication subsystem are derived. Based on these requirements, a preliminary design is developed and the feasibility of implementation determined. To support the Orbital Maneuvering Vehicle and National Space Transportation System, the optical system development is straightforward. The requirements on extra-vehicular activity are such as to allow large fields of uncertainty, thus exacerbating the acquisition problem; however, an approach is given that could mitigate this problem. In general, it is found that such a system could indeed perform the proximity operations mission requirement, with some development required to support extra-vehicular activity.

  17. Endomedullar nail of metacarpal and proximal phalanges

    International Nuclear Information System (INIS)

    Mendez Olaya, Francisco Javier; Sanchez Mesa, Pedro Antonio

    2002-01-01

    Prospective study, series of cases; it included patients with diaphysis fractures and union diaphysis-neck or union diaphysis-base of metacarpal and proximal phalanges, in whom was practiced anterograde intramedullary nailing previous closed reduction of the fracture, using prevent intramedullary nail of 1.6 mm. (cem 16) for the metacarpal fractures, and two nail prevent of 1.0 mm. (cem 10) for the proximal phalangeal fractures. Indications: transverse and oblique short fractures, spiral and with comminuting bicortical. Pursuit average is 5.7 months. Frequency surgical intervened patient: 2.2 each month, using this surgical technique a total of 20 (twenty) patients have been operated, 21 (twenty one) fractures; 16 (sixteen) metacarcal fractures and 5 (five) proximal phalangeal fractures, all of them tested using clinical and radiological parameters. Results: good 82%, regular 18%, and bad 0% obtaining bony consolidation and early rehabilitation with incorporation to their habitual works

  18. Correlation between social proximity and mobility similarity.

    Science.gov (United States)

    Fan, Chao; Liu, Yiding; Huang, Junming; Rong, Zhihai; Zhou, Tao

    2017-09-20

    Human behaviors exhibit ubiquitous correlations in many aspects, such as individual and collective levels, temporal and spatial dimensions, content, social and geographical layers. With rich Internet data of online behaviors becoming available, it attracts academic interests to explore human mobility similarity from the perspective of social network proximity. Existent analysis shows a strong correlation between online social proximity and offline mobility similarity, namely, mobile records between friends are significantly more similar than between strangers, and those between friends with common neighbors are even more similar. We argue the importance of the number and diversity of common friends, with a counter intuitive finding that the number of common friends has no positive impact on mobility similarity while the diversity plays a key role, disagreeing with previous studies. Our analysis provides a novel view for better understanding the coupling between human online and offline behaviors, and will help model and predict human behaviors based on social proximity.

  19. Evaluation and Management of Proximal Humerus Fractures

    Directory of Open Access Journals (Sweden)

    Ekaterina Khmelnitskaya

    2012-01-01

    Full Text Available Proximal humerus fractures are common injuries, especially among older osteoporotic women. Restoration of function requires a thorough understanding of the neurovascular, musculotendinous, and bony anatomy. This paper addresses the relevant anatomy and highlights various management options, including indication for arthroplasty. In the vast majority of cases, proximal humerus fractures may be treated nonoperatively. In the case of displaced fractures, when surgical intervention may be pursued, numerous constructs have been investigated. Of these, the proximal humerus locking plate is the most widely used. Arthroplasty is generally reserved for comminuted 4-part fractures, head-split fractures, or fractures with significant underlying arthritic changes. Reverse total shoulder arthroplasty is reserved for patients with a deficient rotator cuff, or highly comminuted tuberosities.

  20. The Life Saving Effects of Hospital Proximity

    DEFF Research Database (Denmark)

    Bertoli, Paola; Grembi, Veronica

    We assess the lifesaving effect of hospital proximity using data on fatality rates of road-traffic accidents. While most of the literature on this topic is based on changes in distance to the nearest hospital triggered by hospital closures and use OLS estimates, our identification comes from......) increases the fatality rate by 13.84% on the sample average. This is equal to a 0.92 additional death per every 100 accidents. We show that OLS estimates provide a downward biased measure of the real effect of hospital proximity because they do not fully solve spatial sorting problems. Proximity matters...... more when the road safety is low; the emergency service is not properly organized, and the nearest hospital has lower quality standards....

  1. Proximity functions for general right cylinders

    International Nuclear Information System (INIS)

    Kellerer, A.M.

    1981-01-01

    Distributions of distances between pairs of points within geometrical objects, or the closely related proximity functions and geometric reduction factors, have applications to dosimetric and microdosimetric calculations. For convex bodies these functions are linked to the chord-length distributions that result from random intersections by straight lines. A synopsis of the most important relations is given. The proximity functions and related functions are derived for right cylinders with arbitrary cross sections. The solution utilizes the fact that the squares of the distances between two random points are sums of independently distributed squares of distances parallel and perpendicular to the axis of the cylinder. Analogous formulas are derived for the proximity functions or geometric reduction factors for a cylinder relative to a point. This requires only a minor modification of the solution

  2. Industrial Computed Tomography using Proximal Algorithm

    KAUST Repository

    Zang, Guangming

    2016-04-14

    In this thesis, we present ProxiSART, a flexible proximal framework for robust 3D cone beam tomographic reconstruction based on the Simultaneous Algebraic Reconstruction Technique (SART). We derive the proximal operator for the SART algorithm and use it for minimizing the data term in a proximal algorithm. We show the flexibility of the framework by plugging in different powerful regularizers, and show its robustness in achieving better reconstruction results in the presence of noise and using fewer projections. We compare our framework to state-of-the-art methods and existing popular software tomography reconstruction packages, on both synthetic and real datasets, and show superior reconstruction quality, especially from noisy data and a small number of projections.

  3. [Partial replantation following proximal limb injury].

    Science.gov (United States)

    Dubert, T; Malikov, S A; Dinh, A; Kupatadze, D D; Oberlin, C; Alnot, J Y; Nabokov, B B

    2000-11-01

    Proximal replantation is a technically feasible but life-threatening procedure. Indications must be restricted to patients in good condition with a good functional prognosis. The goal of replantation must be focused not only on reimplanting the amputated limb but also on achieving a good functional outcome. For the lower limb, simple terminalization remains the best choice in many cases. When a proximal amputation is not suitable for replantation, the main aim of the surgical procedure must be to reconstruct a stump long enough to permit fitting a prosthesis preserving the function of the adjacent joint. If the proximal stump beyond the last joint is very short, it may be possible to restore some length by partial replantation of spared tissues from the amputated part. We present here the results we obtained following this policy. This series included 16 cases of partial replantations, 14 involving the lower limb and 2 the upper limb. All were osteocutaneous microsurgical transfers. For the lower limb, all transfers recovered protective sensitivity following tibial nerve repair. The functional calcaeoplantar unit was used in 13 cases. The transfer of this specialized weight bearing tissue provided a stable distal surface making higher support unnecessary. In one case, we raised a 13-cm vascularized tibial segment covered with foot skin for additional length. For the upper limb, the osteocutaneous transfer, based on the radial artery, was not reinnervated, but this lack of sensitivity did not impair prosthesis fitting. One vascular failure was finally amputated. This was the only unsuccessful result. For all other patients, the surgical procedure facilitated prosthesis fitting and preserved the proximal joint function despite an initially very proximal amputation. The advantages of partial replantation are obvious compared with simple terminalization or secondary reconstruction. There is no secondary donor site and, because there is no major muscle mass in the

  4. The developmental spectrum of proximal radioulnar synostosis

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Alison M. [University of Manitoba, Winnipeg Regional Health Association Program of Genetics and Metabolism, Winnipeg, MB (Canada); University of Manitoba, Department of Paediatrics and Child Health, Winnipeg, MB (Canada); University of Manitoba, Department of Biochemistry and Medical Genetics, Winnipeg, MB (Canada); University of Manitoba, WRHA Program of Genetics and Metabolism, Departments of Paediatrics and Child Health, Biochemistry and Medical Genetics, Winnipeg, MB (Canada); Kibria, Lisa [University of Manitoba, Department of School of Medical Rehabilitation, Winnipeg, MB (Canada); Reed, Martin H. [University of Manitoba, Department of Paediatrics and Child Health, Winnipeg, MB (Canada); University of Manitoba, Department of Biochemistry and Medical Genetics, Winnipeg, MB (Canada); University of Manitoba, Department of Diagnostic Imaging, Winnipeg, MB (Canada)

    2010-01-15

    Proximal radioulnar synostosis is a rare upper limb malformation. The elbow is first identifiable at 35 days (after conception), at which stage the cartilaginous anlagen of the humerus, radius and ulna are continuous. Subsequently, longitudinal segmentation produces separation of the distal radius and ulna. However, temporarily, the proximal ends are united and continue to share a common perichondrium. We investigated the hypothesis that posterior congenital dislocation of the radial head and proximal radioulnar fusion are different clinical manifestations of the same primary developmental abnormality. Records were searched for ''proximal radioulnar fusion/posterior radial head dislocation'' in patients followed at the local Children's Hospital and Rehabilitation Centre for Children. Relevant radiographic, demographic and clinical data were recorded. Ethics approval was obtained through the University Research Ethics Board. In total, 28 patients met the inclusion criteria. The majority of patients (16) had bilateral involvement; eight with posterior dislocation of the radial head only; five had posterior radial head dislocation with radioulnar fusion and two had radioulnar fusion without dislocation. One patient had bilateral proximal radioulnar fusion and posterior dislocation of the left radial head. Nine patients had only left-sided involvement, and three had only right-sided involvement.The degree of proximal fusion varied, with some patients showing 'complete' proximal fusion and others showing fusion that occurred slightly distal to the radial head: 'partially separated.' Associated disorders in our cohort included Poland syndrome (two patients), Cornelia de Lange syndrome, chromosome anomalies (including tetrasomy X) and Cenani Lenz syndactyly. The suggestion of a developmental relationship between posterior dislocation of the radial head and proximal radioulnar fusion is supported by the fact that both anomalies

  5. Proximity effects in ferromagnet/superconductor structures

    International Nuclear Information System (INIS)

    Yu, H.L.; Sun, G.Y.; Yang, L.Y.; Xing, D.Y.

    2004-01-01

    The Nambu spinor Green's function approach is applied to study proximity effects in ferromagnet/superconductor (FM/SC) structures. They include the induced superconducting order parameter and density of states (DOS) with superconducting feature on the FM side, and spin-dependent DOS within the energy gap on the SC side. The latter indicates an appearance of gapless superconductivity and a coexistence of ferromagnetism and superconductivity in a small regime near the interface. The influence of exchange energy in FM and barrier strength at interface on the proximity effects is discussed

  6. Ultimate and proximate explanations of strong reciprocity.

    Science.gov (United States)

    Vromen, Jack

    2017-08-23

    Strong reciprocity (SR) has recently been subject to heated debate. In this debate, the "West camp" (West et al. in Evol Hum Behav 32(4):231-262, 2011), which is critical of the case for SR, and the "Laland camp" (Laland et al. in Science, 334(6062):1512-1516, 2011, Biol Philos 28(5):719-745, 2013), which is sympathetic to the case of SR, seem to take diametrically opposed positions. The West camp criticizes advocates of SR for conflating proximate and ultimate causation. SR is said to be a proximate mechanism that is put forward by its advocates as an ultimate explanation of human cooperation. The West camp thus accuses advocates of SR for not heeding Mayr's original distinction between ultimate and proximate causation. The Laland camp praises advocates of SR for revising Mayr's distinction. Advocates of SR are said to replace Mayr's uni-directional view on the relation between ultimate and proximate causes by the bi-directional one of reciprocal causation. The paper argues that both the West camp and the Laland camp misrepresent what advocates of SR are up to. The West camp is right that SR is a proximate cause of human cooperation. But rather than putting forward SR as an ultimate explanation, as the West camp argues, advocates of SR believe that SR itself is in need of ultimate explanation. Advocates of SR tend to take gene-culture co-evolutionary theory as the correct meta-theoretical framework for advancing ultimate explanations of SR. Appearances notwithstanding, gene-culture coevolutionary theory does not imply Laland et al.'s notion of reciprocal causation. "Reciprocal causation" suggests that proximate and ultimate causes interact simultaneously, while advocates of SR assume that they interact sequentially. I end by arguing that the best way to understand the debate is by disambiguating Mayr's ultimate-proximate distinction. I propose to reserve "ultimate" and "proximate" for different sorts of explanations, and to use other terms for distinguishing

  7. Infiltrating/sealing proximal caries lesions

    DEFF Research Database (Denmark)

    Martignon, S; Ekstrand, K R; Gomez, J

    2012-01-01

    This randomized split-mouth controlled clinical trial aimed at assessing the therapeutic effects of infiltration vs. sealing for controlling caries progression on proximal surfaces. Out of 90 adult students/patients assessed at university clinics and agreeing to participate, 39, each with 3...... differences in lesion progression between infiltration and placebo (P = 0.0012) and between sealing and placebo (P = 0.0269). The study showed that infiltration and sealing are significantly better than placebo treatment for controlling caries progression on proximal lesions. No significant difference...

  8. Uncemented allograft-prosthetic composite reconstruction of the proximal femur

    Directory of Open Access Journals (Sweden)

    Li Min

    2014-01-01

    Full Text Available Background: Allograft-prosthetic composite can be divided into three groups names cemented, uncemented, and partially cemented. Previous studies have mainly reported outcomes in cemented and partially cemented allograft-prosthetic composites, but have rarely focused on the uncemented allograft-prosthetic composites. The objectives of our study were to describe a surgical technique for using proximal femoral uncemented allograft-prosthetic composite and to present the radiographic and clinical results. Materials and Methods: Twelve patients who underwent uncemented allograft-prosthetic composite reconstruction of the proximal femur after bone tumor resection were retrospectively evaluated at an average followup of 24.0 months. Clinical records and radiographs were evaluated. Results: In our series, union occurred in all the patients (100%; range 5-9 months. Until the most recent followup, there were no cases with infection, nonunion of the greater trochanter, junctional bone resorption, dislocation, allergic reaction, wear of acetabulum socket, recurrence, and metastasis. But there were three periprosthetic fractures which were fixed using cerclage wire during surgery. Five cases had bone resorption in and around the greater trochanter. The average Musculoskeletal Tumor Society (MSTS score and Harris hip score (HHS were 26.2 points (range 24-29 points and 80.6 points (range 66.2-92.7 points, respectively. Conclusions: These results showed that uncemented allograft-prosthetic composite could promote bone union through compression at the host-allograft junction and is a good choice for proximal femoral resection. Although this technology has its own merits, long term outcomes are yet not validated.

  9. Phytochemical screening, proximate analysis and acute toxicity ...

    African Journals Online (AJOL)

    Phytochemical screening results indicate the presence of saponins, flavonoids, phytosterols and phenols. Acute toxicity study showed there was no mortality at 8000 mg/kg of the extract. The results indicate that the plant is rich in phytochemicals and is relatively safe. Key words: Phytochemicals, acute toxicity, proximate ...

  10. PROXIMATE AND ELEMENTAL COMPOSITION OF WHITE GRUBS

    African Journals Online (AJOL)

    DR. AMINU

    This study determined the proximate and mineral element composition of whole white grubs using standard methods of analysis. ... and 12.75 ± 3.65% respectively. Mineral contents of white grub in terms of relative concentration .... of intracellular Ca, bone mineralization, blood coagulation, and plasma membrane potential ...

  11. Phytochemical Screening and Proximate Analysis of Newbouldia ...

    African Journals Online (AJOL)

    The study was conducted to assess the phytochemical and proximate composition of Newboudia laevis leaves and Allium sativum bulb extracts. The leaves and bulbs extracts were analyzed for their chemical composition and antinutritional factors (ANFs) which include moisture, crude protein, crude fat, crude fiber, total ash ...

  12. Phytochemical Screening, Proximate and Mineral Composition of ...

    African Journals Online (AJOL)

    Leaves of sweet potato (Ipomoea batatas) grown in Tepi area was studied for their class of phytochemicals, mineral and proximate composition using standard analytical methods. The phytochemical screening revealed the presence of alkaloids, flavonoid, terpenoids, saponins, quinones, phenol, tannins, amino acid and ...

  13. Phytochemical screening, proximate and elemental analysis of ...

    African Journals Online (AJOL)

    Citrus sinensis was screened for its phytochemical composition and was evaluated for the proximate and elemental analysis. The phytochemical analysis indicated the presence of reducing sugar, saponins, cardiac glycosides, tannins and flavonoids. The elemental analysis indicated the presence of the following mineral ...

  14. Modified Koyanagi Technique in Management of Proximal ...

    African Journals Online (AJOL)

    xp

    Modified Koyanagi Technique in Management of Proximal Hypospadias. Adham Elsaied, Basem Saied, and Mohammed El- ... All operations were performed by the authors,using fine instruments and under 3.5X loupe ... the other needed an operation to close the fistula six months later. The case with meatal recession had ...

  15. Proximity focusing RICH with TOF capabilities

    International Nuclear Information System (INIS)

    Korpar, S.; Adachi, I.; Fujita, K.; Fukushima, T.; Gorisek, A.; Hayashi, D.; Iijima, T.; Ikado, T.; Ishikawa, T.; Kawai, H.; Kozakai, Y.; Krizan, P.; Kuratani, A.; Mazuka, Y.; Nakagawa, T.; Nishida, S.; Ogawa, S.; Pestotnik, R.; Seki, T.; Sumiyoshi, T.; Tabata, M.; Unno, Y.

    2007-01-01

    A proximity focusing RICH counter with a multi-channel micro-channel plate (MCP) PMT was tested as a time-of-flight counter. Cherenkov photons emitted in the radiator medium as well as in the entrance window of the PMT were used for the time-of-flight measurement, and an excellent performance of the counter could be demonstrated

  16. Proximate composition and mycological characterization of peanut ...

    African Journals Online (AJOL)

    SARAH

    2013-12-30

    Dec 30, 2013 ... ABSTRACT. Objective: The aim of this work was to contribute to the food safety of Ivorian consumers by investigating the proximate composition and the toxic fungal contamination of peanut butters offered for retail sale on the different markets of Abidjan. Methodology and results: Peanut butter samples (45) ...

  17. Prosthetic replacement for proximal humeral fractures.

    Science.gov (United States)

    Kontakis, George; Tosounidis, Theodoros; Galanakis, Ioannis; Megas, Panagiotis

    2008-12-01

    The ideal management of complex proximal humeral fractures continues to be debatable. Evolution of proximal humeral fracture management, during the past decade, led to the implementation of many innovations in surgical treatment. Even though the pendulum of treatment seems to swing towards new trends such as locked plating, hemiarthroplasty remains a valid and reliable option that serves the patient's needs well. Hemiarthroplasty is indicated for complex proximal humeral fractures in elderly patients with poor bone stock and when internal fixation is difficult or unreliable. Hemiarthroplasty provides a better result when it is performed early post-injury. Stem height, retroversion and tuberosity positioning are technical aspects of utmost importance. Additionally reverse total shoulder arthroplasty is an alternative new modality that can be used as a primary solution in selected patients with proximal humeral fracture treatment. Failed hemiarthroplasty and fracture sequelae can be successfully managed with reverse total shoulder arthroplasty. Individual decision-making and tailored treatment that takes into consideration the personality of the fracture and the patient's characteristics should be used.

  18. Phytochemistry and proximate composition of ginger ( Zingiber ...

    African Journals Online (AJOL)

    The results of the phytochemical screening showed that alkaloids, carbohydrates, glycosides, proteins, saponins, steroids, flavonoids and terpenoids were present, while reducing sugars, tannins, oils and acid compounds were absent. Similarly, the results of the proximate analysis of the rhizome showed that ginger ...

  19. Disability occurrence and proximity to death

    NARCIS (Netherlands)

    Klijs, Bart; Mackenbach, Johan P.; Kunst, Anton E.

    2010-01-01

    Purpose. This paper aims to assess whether disability occurrence is related more strongly to proximity to death than to age. Method. Self reported disability and vital status were available from six annual waves and a subsequent 12-year mortality follow-up of the Dutch GLOBE longitudinal study.

  20. Proximate composition, bread characteristics and sensory ...

    African Journals Online (AJOL)

    This study was carried out to investigate proximate composition, bread characteristics and sensory evaluation of cocoyam-wheat composite breads at different levels of cocoyam flour substitution for human consumption.A whole wheat bread (WWB) and cocoyam-composite breads (CCB1,CCB 2 and CCB 3) were prepared ...

  1. Repair of esophageal atresia with proximal fistula using endoscopic magnetic compression anastomosis (magnamosis) after staged lengthening.

    Science.gov (United States)

    Dorman, Robert M; Vali, Kaveh; Harmon, Carroll M; Zaritzky, Mario; Bass, Kathryn D

    2016-05-01

    We describe the treatment of a patient with long-gap esophageal atresia with an upper pouch fistula, mircogastria and minimal distal esophageal remnant. After 4.5 months of feeding via gastrostomy, a proximal fistula was identified by bronchoscopy and a thoracoscopic modified Foker procedure was performed reducing the gap from approximately 7-5 cm over 2 weeks of traction. A second stage to ligate the fistula and suture approximate the proximal and distal esophagus resulted in a gap of 1.5 cm. IRB and FDA approval was then obtained for endoscopic placement of 10-French catheter mounted magnets in the proximal and distal pouches promoting a magnetic compression anastomosis (magnamosis). Magnetic coupling occurred at 4 days and after magnet removal at 13 days an esophagram demonstrated a 10 French channel without leak. Serial endoscopic balloon dilation has allowed drainage of swallowed secretions as the baby learns bottling behavior at home.

  2. Proximal tubular hypertrophy and enlarged glomerular and proximal tubular urinary space in obese subjects with proteinuria.

    Directory of Open Access Journals (Sweden)

    Ana Tobar

    Full Text Available BACKGROUND: Obesity is associated with glomerular hyperfiltration, increased proximal tubular sodium reabsorption, glomerular enlargement and renal hypertrophy. A single experimental study reported an increased glomerular urinary space in obese dogs. Whether proximal tubular volume is increased in obese subjects and whether their glomerular and tubular urinary spaces are enlarged is unknown. OBJECTIVE: To determine whether proximal tubules and glomerular and tubular urinary space are enlarged in obese subjects with proteinuria and glomerular hyperfiltration. METHODS: Kidney biopsies from 11 non-diabetic obese with proteinuria and 14 non-diabetic lean patients with a creatinine clearance above 50 ml/min and with mild or no interstitial fibrosis were retrospectively analyzed using morphometric methods. The cross-sectional area of the proximal tubular epithelium and lumen, the volume of the glomerular tuft and of Bowman's space and the nuclei number per tubular profile were estimated. RESULTS: Creatinine clearance was higher in the obese than in the lean group (P=0.03. Proteinuria was similarly increased in both groups. Compared to the lean group, the obese group displayed a 104% higher glomerular tuft volume (P=0.001, a 94% higher Bowman's space volume (P=0.003, a 33% higher cross-sectional area of the proximal tubular epithelium (P=0.02 and a 54% higher cross-sectional area of the proximal tubular lumen (P=0.01. The nuclei number per proximal tubular profile was similar in both groups, suggesting that the increase in tubular volume is due to hypertrophy and not to hyperplasia. CONCLUSIONS: Obesity-related glomerular hyperfiltration is associated with proximal tubular epithelial hypertrophy and increased glomerular and tubular urinary space volume in subjects with proteinuria. The expanded glomerular and urinary space is probably a direct consequence of glomerular hyperfiltration. These effects may be involved in the pathogenesis of obesity

  3. SINA: A test system for proximity fuses

    Science.gov (United States)

    Ruizenaar, M. G. A.

    1989-04-01

    SINA, a signal generator that can be used for testing proximity fuses, is described. The circuitry of proximity fuses is presented; the output signal of the RF circuit results from a mixing of the emitted signal and received signal that is Doppler shifted in frequency by the relative motion of the fuse with respect to the reflecting target of surface. With SINA, digitized and stored target and clutter signals (previously measured) can be transformed to Doppler signals, for example during a real flight. SINA can be used for testing fuse circuitry, for example in the verification of results of computer simulations of the low frequency Doppler signal processing. The software of SINA and its use are explained.

  4. Isolated Proximal Tibiofibular Dislocation during Soccer

    Directory of Open Access Journals (Sweden)

    Casey Chiu

    2015-01-01

    Full Text Available Proximal tibiofibular dislocations are rarely encountered in the Emergency Department (ED. We present a case involving a man presenting to the ED with left knee pain after making a sharp left turn on the soccer field. His physical exam was only remarkable for tenderness over the lateral fibular head. His X-rays showed subtle abnormalities of the tibiofibular joint. The dislocation was reduced and the patient was discharged from the ED with orthopedic follow-up.

  5. Superconducting proximity effect in topological materials

    Science.gov (United States)

    Reeg, Christopher R.

    In recent years, there has been a renewed interest in the proximity effect due to its role in the realization of topological superconductivity. In this dissertation, we discuss several results that have been obtained in the field of proximity-induced superconductivity and relate the results to the search for Majorana fermions. First, we show that repulsive electron-electron interactions can induce a non-Majorana zero-energy bound state at the interface between a conventional superconductor and a normal metal. We show that this state is very sensitive to disorder, owing to its lack of topological protection. Second, we show that Rashba spin-orbit coupling, which is one of the key ingredients in engineering a topological superconductor, induces triplet pairing in the proximity effect. When the spin-orbit coupling is strong (i.e., when the characteristic energy scale for spin-orbit coupling is comparable to the Fermi energy), the induced singlet and triplet pairing amplitudes can be comparable in magnitude. Finally, we discuss how the size of the proximity-induced gap, which appears in a low-dimensional material coupled to a superconductor, evolves as the thickness of the (quasi-)low-dimensional material is increased. We show that the induced gap can be comparable to the bulk energy gap of the underlying superconductor in materials that are much thicker than the Fermi wavelength, even in the presence of an interfacial barrier and strong Fermi surface mismatch. This result has important experimental consequences for topological superconductivity, as a sizable gap is required to isolate and detect the Majorana modes.

  6. [Proximity and breastfeeding at the maternity hospital].

    Science.gov (United States)

    Fradin-Charrier, Anne-Claire

    2015-01-01

    The establishment of breastfeeding, as well as its duration, are facilitated through the proximity of the mother with her new baby. However, in maternity hospitals, breastfeeding mothers very often leave their baby in the nursery at night time. A study carried out in 2014 in several maternity hospitals put forward suggestions and highlighted areas to improve in everyday practice. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  7. Proximity effects in topological insulator heterostructures

    International Nuclear Information System (INIS)

    Li Xiao-Guang; Wu Guang-Fen; Zhang Gu-Feng; Culcer Dimitrie; Zhang Zhen-Yu; Chen Hua

    2013-01-01

    Topological insulators (TIs) are bulk insulators that possess robust helical conducting states along their interfaces with conventional insulators. A tremendous research effort has recently been devoted to Tl-based heterostructures, in which conventional proximity effects give rise to a series of exotic physical phenomena. This paper reviews our recent studies on the potential existence of topological proximity effects at the interface between a topological insulator and a normal insulator or other topologically trivial systems. Using first-principles approaches, we have realized the tunability of the vertical location of the topological helical state via intriguing dual-proximity effects. To further elucidate the control parameters of this effect, we have used the graphene-based heterostructures as prototypical systems to reveal a more complete phase diagram. On the application side of the topological helical states, we have presented a catalysis example, where the topological helical state plays an essential role in facilitating surface reactions by serving as an effective electron bath. These discoveries lay the foundation for accurate manipulation of the real space properties of the topological helical state in TI-based heterostructures and pave the way for realization of the salient functionality of topological insulators in future device applications. (topical review - low-dimensional nanostructures and devices)

  8. [Augmentation technique on the proximal humerus].

    Science.gov (United States)

    Scola, A; Gebhard, F; Röderer, G

    2015-09-01

    The treatment of osteoporotic fractures is still a challenge. The advantages of augmentation with respect to primary in vitro stability and the clinical use for the proximal humerus are presented in this article. In this study six paired human humeri were randomized into an augmented and a non-augmented group. Osteosynthesis was performed with a PHILOS plate (Synthes®). In the augmented group the two screws finding purchase in the weakest cancellous bone were augmented. The specimens were tested in a 3-part fracture model in a varus bending test. The augmented PHILOS plates withstood significantly more load cycles until failure. The correlation to bone mineral density (BMD) showed that augmentation could partially compensate for low BMD. The augmentation of the screws in locked plating in a proximal humerus fracture model is effective in improving the primary stability in a cyclic varus bending test. The targeted augmentation of two particular screws in a region of low bone quality within the humeral head was almost as effective as four screws with twice the amount of bone cement. Screw augmentation combined with a knowledge of the local bone quality could be more effective in enhancing the primary stability of a proximal humerus locking plate because the effect of augmentation can be exploited more effectively limiting it to the degree required. The technique of augmentation is simple and can be applied in open and minimally invasive procedures. When the correct procedure is used, complications (cement leakage into the joint) can be avoided.

  9. A proximity effect in adults' contamination intuitions

    Directory of Open Access Journals (Sweden)

    Laura R. Kim

    2011-04-01

    Full Text Available Magical beliefs about contagion via contact (Rozin, Nemeroff, Wane, and Sherrod, 1989 may emerge when people overgeneralize real-world mechanisms of contamination beyond their appropriate boundaries (Lindeman and Aarnio, 2007. Do people similarly overextend knowledge of airborne contamination mechanisms? Previous work has shown that very young children believe merely being close to a contamination source can contaminate an item (Springer and Belk 1994; we asked whether this same hyper-avoidant intuition is also reflected in adults' judgments. In two studies, we measured adults' ratings of the desirability of an object that had made contact with a source of contamination, an object nearby that had made no contact with the contaminant, and an object far away that had also made no contact. Adults showed a clear proximity effect, wherein objects near the contamination source were perceived to be less desirable than those far away, even though a separate group of adults unanimously acknowledged that contaminants could not possibly have made contact with either the nearby or far-away object (Study 1. The proximity effect also remained robust when a third group of adults was explicitly told that no contaminating particles had made contact with the objects at any time (Study 2. We discuss implications of our findings for extending the scope of magical contagion effects beyond the contact principle, for understanding the persistence of intuitive theories despite broad acceptance of science-based theories, and for constraining interpretations of the developmental work on proximity beliefs.

  10. A Regularized Algorithm for the Proximal Split Feasibility Problem

    Directory of Open Access Journals (Sweden)

    Zhangsong Yao

    2014-01-01

    Full Text Available The proximal split feasibility problem has been studied. A regularized method has been presented for solving the proximal split feasibility problem. Strong convergence theorem is given.

  11. Treatment of proximal ulna and olecranon fractures by dorsal plating

    NARCIS (Netherlands)

    Kloen, Peter; Buijze, Geert A.

    2009-01-01

    OBJECTIVE : Anatomic reconstruction of proximal ulna and olecranon fractures allowing early mobilization and prevention of ulnohumeral arthritis. INDICATIONS : Comminuted olecranon or proximal ulna fractures (including Monteggia fractures), olecranon fractures extending distally from the coronoid

  12. Common mutations identified in the MLH1 gene in familial Lynch syndrome

    OpenAIRE

    Jisha Elias; Coral Karunakaran; Snigdha Majumder; Malini Manoharan; Rakshit Shah; Yogesh Mistry; Rajesh Ramanuj; Niraj Bhatt; Arati Khanna- Gupta

    2017-01-01

    Lynch syndrome (Hereditary Non Polyposis Colorectal Cancer, HNPCC) is one of the most common hereditary familial colorectal cancers (CRC) with an autosomal dominant pattern of inheritance. It accounts for 2-5% of the total CRCs reported worldwide. Although a lower incidence for CRCs have been observed in India, the last decade has shown a remarkable increase of CRC incidences (2-4 %). Features of Lynch syndrome associated colorectal cancer include early age of cancer onset, accelerated car...

  13. Meiotic interference among MLH1 foci requires neither an intact axial element structure nor full synapsis

    NARCIS (Netherlands)

    Boer, den E.; Dietrich, A.J.J.; Höög, C.; Stam, P.; Heyting, C.

    2007-01-01

    During meiosis, homologous chromosomes (homologs) perform reciprocal exchanges (crossovers) at a high frequency. Crossovers display interference, i.e. their spacing is more even than would be expected if they were placed randomly along the chromosomes. Concomitantly with crossover formation,

  14. The mismatch repair protein MLH1 marks a subset of strongly interfering crossovers in tomato

    NARCIS (Netherlands)

    Lhuissier, F.G.P.; Offenberg, H.H.; Wittich, P.E.; Vischer, N.O.E.; Heyting, C.

    2007-01-01

    In most eukaryotes, the prospective chromosomal positions of meiotic crossovers are marked during meiotic prophase by protein complexes called late recombination nodules (LNs). In tomato (Solanum lycopersicum), a cytological recombination map has been constructed based on LN positions. We

  15. RESEARCH ARTICLE Small suitability of the DLEC1,MLH1 and ...

    Indian Academy of Sciences (India)

    Navya

    However these finding were not confirmed in further studies, f. ex. on different populations. Besides there were no ... NSCLC was characterized using International System of Clinico-Morphological. Classification of ... Experimental protocols.

  16. Strong Proximities on Smooth Manifolds and Vorono\\" i Diagrams

    OpenAIRE

    Peters, J. F.; Guadagni, C.

    2015-01-01

    This article introduces strongly near smooth manifolds. The main results are (i) second countability of the strongly hit and far-miss topology on a family $\\mathcal{B}$ of subsets on the Lodato proximity space of regular open sets to which singletons are added, (ii) manifold strong proximity, (iii) strong proximity of charts in manifold atlases implies that the charts have nonempty intersection. The application of these results is given in terms of the nearness of atlases and charts of proxim...

  17. Biomarkers in the Detection of Prostate Cancer in African Americans

    Science.gov (United States)

    2012-09-01

    complex of MSH molecules recog- nizes the mismatched nucleotides and MLH1/ PMS2 and MLH1/MLH3 complexes are involved in attach- ment, removal of the...mismatch and repair. Over- all, MSH2, MLH1, MLH3, PMS1, PMS2 , MSH3 and MSH6 are involved in detection-excision and repair of mismatched nucleotides. When...there are mutations in MSH2, MSH6, MLH1 or PMS2 or loss of expression of MSH2 or MLH1 caused by, for example, methylation of the promoters of these

  18. Critical Proximity as a Methodological Move in Techno-Anthropology

    DEFF Research Database (Denmark)

    Birkbak, Andreas; Petersen, Morten Krogh; Elgaard Jensen, Torben

    2015-01-01

    proximity.’ Critical proximity offers an alternative to critical distance, especially with respect to avoiding premature references to abstract panoramas such as democratization and capitalist exploitation in the quest to conduct ‘critical’ analysis. Critical proximity implies, instead, granting the beings...

  19. 75 FR 5009 - Proximity Detection Systems for Underground Mines

    Science.gov (United States)

    2010-02-01

    ... Proximity Detection Systems for Underground Mines AGENCY: Mine Safety and Health Administration, Labor... information regarding whether the use of proximity detection systems would reduce the risk of accidents where... . Information on MSHA-approved proximity detection systems is available on the Internet at http://www.msha.gov...

  20. Proximal sensing for soil carbon accounting

    Science.gov (United States)

    England, Jacqueline R.; Viscarra Rossel, Raphael A.

    2018-05-01

    Maintaining or increasing soil organic carbon (C) is vital for securing food production and for mitigating greenhouse gas (GHG) emissions, climate change, and land degradation. Some land management practices in cropping, grazing, horticultural, and mixed farming systems can be used to increase organic C in soil, but to assess their effectiveness, we need accurate and cost-efficient methods for measuring and monitoring the change. To determine the stock of organic C in soil, one requires measurements of soil organic C concentration, bulk density, and gravel content, but using conventional laboratory-based analytical methods is expensive. Our aim here is to review the current state of proximal sensing for the development of new soil C accounting methods for emissions reporting and in emissions reduction schemes. We evaluated sensing techniques in terms of their rapidity, cost, accuracy, safety, readiness, and their state of development. The most suitable method for measuring soil organic C concentrations appears to be visible-near-infrared (vis-NIR) spectroscopy and, for bulk density, active gamma-ray attenuation. Sensors for measuring gravel have not been developed, but an interim solution with rapid wet sieving and automated measurement appears useful. Field-deployable, multi-sensor systems are needed for cost-efficient soil C accounting. Proximal sensing can be used for soil organic C accounting, but the methods need to be standardized and procedural guidelines need to be developed to ensure proficient measurement and accurate reporting and verification. These are particularly important if the schemes use financial incentives for landholders to adopt management practices to sequester soil organic C. We list and discuss requirements for developing new soil C accounting methods based on proximal sensing, including requirements for recording, verification, and auditing.

  1. Keldysh proximity action for disordered superconductors

    International Nuclear Information System (INIS)

    Feigel'man, M.V.; Larkin, A.I.; Skvortsov, M.A.

    2005-01-01

    We review a novel approach to the superconductive proximity effect in disordered normal-superconducting (N-S) structures. The method is based on the multicharge Keldysh action and is suitable for the treatment of interaction and fluctuation effects. As an application of the formalism, we study the subgap conductance and noise in two-dimensional N-S system in the presence of the electron-electron interaction in the Cooper channel. It is shown that singular nature of the interaction correction at large scales leads to a nonmonotonous temperature, voltage and magnetic field dependence of the Andreev conductance. (author)

  2. Phonon structure in proximity tunnel junctions

    International Nuclear Information System (INIS)

    Zarate, H.G.; Carbotte, J.P.

    1985-01-01

    We have iterated to convergence, for the first time, a set of four coupled real axis Eliashberg equations for the superconducting gap and renormalization functions on each side of a proximity sandwich. We find that the phenomenological procedures developed to extract the size of the normal side electron-phonon interaction from tunneling data are often reasonable but may in some cases need modifications. In all the cases considered the superconducting phonon structure reflected on the normal side, as well as other structures, shows considerable agreement with experiment as to size, shape, and variation with barrier transmission coefficient. Finally, we study the effects of depairing on these structures

  3. Proximal iliotibial band syndrome: case report

    Directory of Open Access Journals (Sweden)

    Guilherme Guadagnini Falotico

    2013-08-01

    Full Text Available OBJECTIVE: The overuse injuries in the hip joint occur commonly in sports practitioners and currently due to technical advances in diagnostic imaging, especially magnetic resonance imaging (MRI, are often misdiagnosed. Recently, a group of people were reported, all female, with pain and swelling in the pelvic region.T2-weighted MRI showed increased signal in the enthesis of the iliotibial band (ITB along the lower border of the iliac tubercle. We report a case of a 34 year old woman, non-professional runner, with pain at the iliac crest with no history of trauma and whose MRI was compatible with the proximal iliotibial band syndrome.

  4. Noise measurements on proximity effect bridges

    International Nuclear Information System (INIS)

    Decker, S.K.; Mercereau, J.E.

    1975-01-01

    Audio frequency noise density measurements were performed on weakly superconducting proximity effect bridges on using a cooled transformer and room temperature low noise preamplifier. The noise temperature of the measuring system is approximately 4 0 K for a 0.9 Ω resistor. Noise density was measured as a function of bias current and temperature for the bridges. Excess noise above that expected from Johnson noise for a resistor equal to the dynamic resistance of the bridges was observed in the region near the critical current of the device. At high currents compared to the critical current, the noise density closely approaches that given by Johnson noise

  5. Congenital anomalies and proximity to landfill sites.

    LENUS (Irish Health Repository)

    Boyle, E

    2004-01-01

    The occurrence of congenital anomalies in proximity to municipal landfill sites in the Eastern Region (counties Dublin, Kildare, Wicklow) was examined by small area (district electoral division), distance and clustering tendancies in relation to 83 landfills, five of which were major sites. The study included 2136 cases of congenital anomaly, 37,487 births and 1423 controls between 1986 and 1990. For the more populous areas of the region 50% of the population lived within 2-3 km of a landfill and within 4-5 km for more rural areas. In the area-level analysis, the standardised prevalence ratios, empirical and full Bayesian modelling, and Kulldorff\\'s spatial scan statistic found no association between the residential area of cases and location of landfills. In the case control analysis, the mean distance of cases and controls from the nearest landfill was similar. The odds ratios of cases compared to controls for increasing distances from all landfills and major landfills showed no significant difference from the baseline value of 1. The kernel and K methods showed no tendency of cases to cluster in relationship to landfills. In conclusion, congenital anomalies were not found to occur more commonly in proximity to municipal landfills.

  6. Obesity and supermarket access: proximity or price?

    Science.gov (United States)

    Drewnowski, Adam; Aggarwal, Anju; Hurvitz, Philip M; Monsivais, Pablo; Moudon, Anne V

    2012-08-01

    We examined whether physical proximity to supermarkets or supermarket price was more strongly associated with obesity risk. The Seattle Obesity Study (SOS) collected and geocoded data on home addresses and food shopping destinations for a representative sample of adult residents of King County, Washington. Supermarkets were stratified into 3 price levels based on average cost of the market basket. Sociodemographic and health data were obtained from a telephone survey. Modified Poisson regression was used to test the associations between obesity and supermarket variables. Only 1 in 7 respondents reported shopping at the nearest supermarket. The risk of obesity was not associated with street network distances between home and the nearest supermarket or the supermarket that SOS participants reported as their primary food source. The type of supermarket, by price, was found to be inversely and significantly associated with obesity rates, even after adjusting for individual-level sociodemographic and lifestyle variables, and proximity measures (adjusted relative risk=0.34; 95% confidence interval=0.19, 0.63) Improving physical access to supermarkets may be one strategy to deal with the obesity epidemic; improving economic access to healthy foods is another.

  7. Children’s proximal societal conditions

    DEFF Research Database (Denmark)

    Stanek, Anja Hvidtfeldt

    or the children’s everyday life, but something that is represented through societal structures and actual persons participating (in political ways) within the institutional settings, in ways that has meaning to children’s possibilities to participate, learn and develop. Understanding school or daycare as (part of......) the children’s proximal societal conditions for development and learning, means for instance that considerations about an inclusive agenda in a (Danish) welfare state with well-developed school- and daycare system, are no longer simply thoughts about the school having space for as many pupils as possible...... (schools for all). Such thoughts can or should be supplemented by reflections about which version of ‘the societal’ we wish to present our children with, and which version of ‘the societal’ we wish to set up as the condition for children’s participation and development. These questions require an ethical...

  8. Proximal tubular dysfunction as an indicator of chronic graft dysfunction

    Directory of Open Access Journals (Sweden)

    N.O.S. Câmara

    2009-03-01

    Full Text Available New strategies are being devised to limit the impact of renal sclerosis on graft function. Individualization of immunosuppression, specifically the interruption of calcineurin-inhibitors has been tried in order to promote better graft survival once chronic graft dysfunction has been established. However, the long-term impact of these approaches is still not totally clear. Nevertheless, patients at higher risk for tubular atrophy and interstitial fibrosis (TA/IF development should be carefully monitored for tubular function as well as glomerular performance. Since tubular-interstitial impairment is an early event in TA/IF pathogenesis and associated with graft function, it seems reasonable that strategies directed at assessing tubular structural integrity and function would yield important functional and prognostic data. The measurement of small proteins in urine such as α-1-microglobulin, N-acetyl-beta-D-glucosaminidase, alpha/pi S-glutathione transferases, β-2 microglobulin, and retinol binding protein is associated with proximal tubular cell dysfunction. Therefore, its straightforward assessment could provide a powerful tool in patient monitoring and ongoing clinical assessment of graft function, ultimately helping to facilitate longer patient and graft survival associated with good graft function.

  9. Distributed Autonomous Control of Multiple Spacecraft During Close Proximity Operations

    National Research Council Canada - National Science Library

    McCamish, Shawn B

    2007-01-01

    This research contributes to multiple spacecraft control by developing an autonomous distributed control algorithm for close proximity operations of multiple spacecraft systems, including rendezvous...

  10. PROXIMAL DISABILITY AND SPINAL DEFORMITY INDEX IN PATIENTS WITH PROXIMAL FEMUR FRACTURES

    Directory of Open Access Journals (Sweden)

    Sylvio Mistro Neto

    2015-12-01

    Full Text Available Objective : To evaluate the quality of life related to the spine in patients with proximal femoral fractures. Methods : Study conducted in a tertiary public hospital in patients with proximal femoral fractures caused by low-energy trauma, through the Oswestry Disability Index questionnaire to asses complaints related to the spine at the time of life prior to the femoral fracture. The thoracic and lumbar spine of patients were also evaluated applying the radiographic index described by Gennant (Spinal Deformity Index, which assesses the number and severity of fractures. Results : Seventeen subjects completed the study. All had some degree of vertebral fracture. Patients were classified in the categories of severe and very severe disability in the questionnaire about quality of life. It was found that the higher SDI, the better the quality of life. Conclusion : There is a strong association of disability related to the spine in patients with proximal femoral fracture, and this complaint must be systematically evaluated in patients with appendicular fracture.

  11. Initial outcome and efficacy of S3 proximal humerus locking plate in the treatment of proximal humerus fractures

    International Nuclear Information System (INIS)

    Zhang Zhiming; Zhu Xuesong; Bao Zhaohua; Yang Huilin

    2012-01-01

    Objective: to explore the initial outcome and efficacy of S 3 proximal humerus locking plate in the treatment of proximal humerus fractures. Methods: Twenty-two patients with proximal humerus fracture were treated with the S 3 proximal humerus locking plate. Most of the fractures were complex, two-part (n=4), three-part (n=11) and four-part (n=7) fractures according to the Neer classification of the proximal humerus fractures. Results: All patients were followed up for 3∼15 months. There were no complications related to the implant including loosening or breakage of the plate. Good and excellent results were documented in 17 patients fair results in 4 patients according the Neer scores of shoulder. Conclusion: New design concepts of S 3 proximal humerus plate provide the subchondral support and the internal fixation support. With the addition of the proper exercise of the shoulder joint, the outcomes would be satisfied. (authors)

  12. Health Promotion

    DEFF Research Database (Denmark)

    Povlsen, Lene; Borup, I.

    2015-01-01

    and Adolescent Health Promotion', Salutogenesis - from theory to practice' and Health, Stress and Coping'. More than half of all doctoral theses undertaken at NHV during these years had health promotion as their theme. As a derivative, the Nordic Health Promotion Research Network (NHPRN) was established in 2007......In 1953 when the Nordic School of Public Health was founded, the aim of public health programmes was disease prevention more than health promotion. This was not unusual, since at this time health usually was seen as the opposite of disease and illness. However, with the Ottawa Charter of 1986......, the World Health Organization made a crucial change to view health not as a goal in itself but as the means to a full life. In this way, health promotion became a first priority and fundamental action for the modern society. This insight eventually reached NHV and in 2002 - 50 years after the foundation...

  13. Proximity Operations and Docking Sensor Development

    Science.gov (United States)

    Howard, Richard T.; Bryan, Thomas C.; Brewster, Linda L.; Lee, James E.

    2009-01-01

    The Next Generation Advanced Video Guidance Sensor (NGAVGS) has been under development for the last three years as a long-range proximity operations and docking sensor for use in an Automated Rendezvous and Docking (AR&D) system. The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. That flight proved that the United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transport Systems (COTS) Automated Rendezvous and Docking (AR&D). NASA video sensors have worked well in the past: the AVGS used on the Demonstration of Autonomous Rendezvous Technology (DART) mission operated successfully in spot mode out to 2 km, and the first generation rendezvous and docking sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on Space Shuttle flights in 1997 and 1998. 12 Parts obsolescence issues prevent the construction of more AVGS units, and the next generation sensor was updated to allow it to support the CEV and COTS programs. The flight proven AR&D sensor has been redesigned to update parts and add additional capabilities for CEV and COTS with the development of the Next Generation AVGS at the Marshall Space Flight Center. The obsolete imager and processor are being replaced with new radiation tolerant parts. In addition, new capabilities include greater sensor range, auto ranging capability, and real-time video output. This paper presents some sensor hardware trades, use of highly integrated laser components, and addresses the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS) and other Constellation vehicles. It also discusses approaches for upgrading AVGS to address parts obsolescence, and concepts for minimizing the sensor footprint, weight, and power requirements

  14. Proximity coupling in superconductor-graphene heterostructures

    Science.gov (United States)

    Lee, Gil-Ho; Lee, Hu-Jong

    2018-05-01

    This review discusses the electronic properties and the prospective research directions of superconductor-graphene heterostructures. The basic electronic properties of graphene are introduced to highlight the unique possibility of combining two seemingly unrelated physics, superconductivity and relativity. We then focus on graphene-based Josephson junctions, one of the most versatile superconducting quantum devices. The various theoretical methods that have been developed to describe graphene Josephson junctions are examined, together with their advantages and limitations, followed by a discussion on the advances in device fabrication and the relevant length scales. The phase-sensitive properties and phase-particle dynamics of graphene Josephson junctions are examined to provide an understanding of the underlying mechanisms of Josephson coupling via graphene. Thereafter, microscopic transport of correlated quasiparticles produced by Andreev reflections at superconducting interfaces and their phase-coherent behaviors are discussed. Quantum phase transitions studied with graphene as an electrostatically tunable 2D platform are reviewed. The interplay between proximity-induced superconductivity and the quantum-Hall phase is discussed as a possible route to study topological superconductivity and non-Abelian physics. Finally, a brief summary on the prospective future research directions is given.

  15. [Ophthalmologists in the proximity of Adolf Hitler].

    Science.gov (United States)

    Rohrbach, J M

    2012-10-01

    Adolf Hitler met or at least knew about 5 ophthalmologists. The chair of ophthalmology in Berlin, Walther Löhlein, personally examined Hitler's eyes at least two times. The chair of ophthalmology in Breslau, Walter Dieter, developed "air raid protection spectacles" with the aid of high representatives of the NS-system and probably Adolf Hitler himself. Heinrich Wilhelm Kranz became rector of the universities of Giessen and Frankfurt/Main. He was known as a very strict advocate of the NS-race hygiene. Werner Zabel made plans for Hitler's diet and tried to interfere with Hitler's medical treatment. Finally, Hellmuth Unger was an influential representative of the medical press and a famous writer. Three of his novels with medical topics were made into a film which Hitler probably saw. Hitler had, so to say, a small "ophthalmological proximity" which, however, did not play a significant role for himself or the NS-state. © Georg Thieme Verlag KG Stuttgart · New York.

  16. Semiconductor detectors with proximity signal readout

    International Nuclear Information System (INIS)

    Asztalos, Stephen J.

    2012-01-01

    Semiconductor-based radiation detectors are routinely used for the detection, imaging, and spectroscopy of x-rays, gamma rays, and charged particles for applications in the areas of nuclear and medical physics, astrophysics, environmental remediation, nuclear nonproliferation, and homeland security. Detectors used for imaging and particle tracking are more complex in that they typically must also measure the location of the radiation interaction in addition to the deposited energy. In such detectors, the position measurement is often achieved by dividing or segmenting the electrodes into many strips or pixels and then reading out the signals from all of the electrode segments. Fine electrode segmentation is problematic for many of the standard semiconductor detector technologies. Clearly there is a need for a semiconductor-based radiation detector technology that can achieve fine position resolution while maintaining the excellent energy resolution intrinsic to semiconductor detectors, can be fabricated through simple processes, does not require complex electrical interconnections to the detector, and can reduce the number of required channels of readout electronics. Proximity electrode signal readout (PESR), in which the electrodes are not in physical contact with the detector surface, satisfies this need

  17. Imaging of rectus femoris proximal tendinopathies

    International Nuclear Information System (INIS)

    Pesquer, Lionel; Poussange, Nicolas; Meyer, Philippe; Dallaudiere, Benjamin; Feldis, Matthieu; Sonnery-Cottet, Bertrand; Graveleau, Nicolas

    2016-01-01

    The rectus femoris is the most commonly injured muscle of the anterior thigh among athletes, especially soccer players. Although the injury pattern of the muscle belly is well documented, less is known about the anatomy and specific lesions of the proximal tendons. For each head, three distinctive patterns may be encountered according to the location of the injury, which can be at the enthesis, within the tendon, or at the musculotendinous junction. In children, injuries correspond most commonly to avulsion of the anteroinferior iliac spine from the direct head and can lead to subspine impingement. Calcific tendinitis and traumatic tears may be encountered in adults. Recent studies have shown that traumatic injuries of the indirect head may be underdiagnosed and that injuries of both heads may have a surgical issue. Finally, in the case of tears, functional outcome and treatment may vary if the rupture involves one or both tendons and if the tear is partial or complete. Thus, it is mandatory for the radiologist to know the different ultrasound and magnetic resonance imaging (MRI) patterns of these lesions in order to provide accurate diagnosis and treatment. The purpose of this article is to recall the anatomy of the two heads of rectus femoris, describe a reliable method of assessment with ultrasound and MRI and know the main injury patterns, through our own experience and literature review. (orig.)

  18. Proximal spinal muscular atrophy: current orthopedic perspective

    Directory of Open Access Journals (Sweden)

    Haaker G

    2013-11-01

    Full Text Available Gerrit Haaker, Albert Fujak Department of Orthopaedic Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany Abstract: Spinal muscular atrophy (SMA is a hereditary neuromuscular disease of lower motor neurons that is caused by a defective "survival motor neuron" (SMN protein that is mainly associated with proximal progressive muscle weakness and atrophy. Although SMA involves a wide range of disease severity and a high mortality and morbidity rate, recent advances in multidisciplinary supportive care have enhanced quality of life and life expectancy. Active research for possible treatment options has become possible since the disease-causing gene defect was identified in 1995. Nevertheless, a causal therapy is not available at present, and therapeutic management of SMA remains challenging; the prolonged survival is increasing, especially orthopedic, respiratory and nutritive problems. This review focuses on orthopedic management of the disease, with discussion of key aspects that include scoliosis, muscular contractures, hip joint disorders, fractures, technical devices, and a comparative approach of conservative and surgical treatment. Also emphasized are associated complications including respiratory involvement, perioperative care and anesthesia, nutrition problems, and rehabilitation. The SMA disease course can be greatly improved with adequate therapy with established orthopedic procedures in a multidisciplinary therapeutic approach. Keywords: spinal muscular atrophy, scoliosis, contractures, fractures, lung function, treatment, rehabilitation, surgery, ventilation, nutrition, perioperative management

  19. Imaging of rectus femoris proximal tendinopathies

    Energy Technology Data Exchange (ETDEWEB)

    Pesquer, Lionel; Poussange, Nicolas; Meyer, Philippe; Dallaudiere, Benjamin; Feldis, Matthieu [Clinique du Sport de Bordeaux, Centre d' Imagerie Osteo-articulaire, Merignac (France); Sonnery-Cottet, Bertrand [Groupe Ramsay Generale de Sante - Hopital Prive Jean Mermoz, Centre Orthopedique Santy, Lyon (France); Graveleau, Nicolas [Clinique du Sport de Bordeaux, Centre de Chirurgie Orthopedique et Sportive, Merignac (France)

    2016-07-15

    The rectus femoris is the most commonly injured muscle of the anterior thigh among athletes, especially soccer players. Although the injury pattern of the muscle belly is well documented, less is known about the anatomy and specific lesions of the proximal tendons. For each head, three distinctive patterns may be encountered according to the location of the injury, which can be at the enthesis, within the tendon, or at the musculotendinous junction. In children, injuries correspond most commonly to avulsion of the anteroinferior iliac spine from the direct head and can lead to subspine impingement. Calcific tendinitis and traumatic tears may be encountered in adults. Recent studies have shown that traumatic injuries of the indirect head may be underdiagnosed and that injuries of both heads may have a surgical issue. Finally, in the case of tears, functional outcome and treatment may vary if the rupture involves one or both tendons and if the tear is partial or complete. Thus, it is mandatory for the radiologist to know the different ultrasound and magnetic resonance imaging (MRI) patterns of these lesions in order to provide accurate diagnosis and treatment. The purpose of this article is to recall the anatomy of the two heads of rectus femoris, describe a reliable method of assessment with ultrasound and MRI and know the main injury patterns, through our own experience and literature review. (orig.)

  20. Proximate analysis of female population of wild feather back fish ...

    African Journals Online (AJOL)

    User

    2011-05-09

    May 9, 2011 ... Key words: Body composition, Notopterus notopterus, condition factor, wild fish. INTRODUCTION. Proximate body composition is the analysis of water, fat, protein and ash contents of the fish (Love, 1980). Proximate composition is a good indicator of physiology which is needed for routine analysis of ...

  1. Proximate analysis of Lentinus squarrosulus (Mont.) Singer and ...

    African Journals Online (AJOL)

    Each of the mushroom species was separated into its stipe and pileus and used for proximate analysis. There was a highly significant difference (p<0.01) in the proximate composition of the two species. P. atroumbonata had significantly higher crude protein, crude fibre and moisture content than L. squarrosulus while the ...

  2. Proximal Focal Femoral Deficiency in Ibadan a Developing ...

    African Journals Online (AJOL)

    The cultural aversion to amputation in our environment makes it difficult to employ that option of treatment. Proximal focal femoral deficiency in Ibadan a developing country's perspective and a review of the literature. Keywords: Proximal focal femoral deficiency , congenital malformations , limb malformations , lower limb ...

  3. Proximity approach to problems in topology and analysis

    CERN Document Server

    Naimpally, Somashekhar

    2009-01-01

    Dieses Buch konzentriert das aktuelle Gesamtwissen zum Proximity-Konzept und stellt es dem Leser in gut strukturierter Form dar. Hauptaugenmerk liegt auf den vielfältigen Möglichkeiten, die sich aus dem Proximity-Konzept der räumlichen Nähe und seiner Verallgemeinerung im Nearness-Konzept ergeben.

  4. Systemic calciphylaxis presenting as a painful, proximal myopathy.

    OpenAIRE

    Edelstein, C. L.; Wickham, M. K.; Kirby, P. A.

    1992-01-01

    A renal transplant patient who presented with a painful, proximal myopathy due to systemic calciphylaxis is described. The myopathy preceded the characteristic skin and soft tissue necrosis. Systemic calciphylaxis should be considered in a dialysis or a renal transplant patient presenting with a painful proximal myopathy even in the absence of necrotic skin lesions.

  5. Genetics Home Reference: proximal 18q deletion syndrome

    Science.gov (United States)

    ... characteristic features. Most cases of proximal 18q deletion syndrome are the result of a new (de novo) deletion and are not inherited from a ... J, Fox PT, Stratton RF, Perry B, Hale DE. Recurrent interstitial deletions of proximal 18q: a new syndrome involving expressive speech delay. Am J Med Genet ...

  6. Proximal soil sensors and data fusion for precision agriculture

    NARCIS (Netherlands)

    Mahmood, H.S.

    2013-01-01

    different remote and proximal soil sensors are available today that can scan entire fields and give detailed information on various physical, chemical, mechanical and biological soil properties. The first objective of this thesis was to evaluate different proximal soil sensors available today and to

  7. Two Stages repair of proximal hypospadias: Review of 33 cases

    African Journals Online (AJOL)

    HussamHassan

    Background/Purpose: Proximal hypospadias with chordee is the most challenging variant of hypospadias to reconstruct. During the last 10 years, the approach to sever hypospadias has been controversial. Materials & Methods: During the period from June 2002 to December 2009, I performed 33 cases with proximal.

  8. Proximity correction of high-dosed frame with PROXECCO

    Science.gov (United States)

    Eisenmann, Hans; Waas, Thomas; Hartmann, Hans

    1994-05-01

    Usefulness of electron beam lithography is strongly related to the efficiency and quality of methods used for proximity correction. This paper addresses the above issue by proposing an extension to the new proximity correction program PROXECCO. The combination of a framing step with PROXECCO produces a pattern with a very high edge accuracy and still allows usage of the fast correction procedure. Making a frame with a higher dose imitates a fine resolution correction where the coarse part is disregarded. So after handling the high resolution effect by means of framing, an additional coarse correction is still needed. Higher doses have a higher contribution to the proximity effect. This additional proximity effect is taken into account with the help of the multi-dose input of PROXECCO. The dose of the frame is variable, depending on the deposited energy coming from backscattering of the proximity. Simulation proves the very high edge accuracy of the applied method.

  9. Interactive orbital proximity operations planning system

    Science.gov (United States)

    Grunwald, Arthur J.; Ellis, Stephen R.

    1990-01-01

    An interactive graphical planning system for on-site planning of proximity operations in the congested multispacecraft environment about the space station is presented. The system shows the astronaut a bird's eye perspective of the space station, the orbital plane, and the co-orbiting spacecraft. The system operates in two operational modes: (1) a viewpoint mode, in which the astronaut is able to move the viewpoint around in the orbital plane to range in on areas of interest; and (2) a trajectory design mode, in which the trajectory is planned. Trajectory design involves the composition of a set of waypoints which result in a fuel-optimal trajectory which satisfies all operational constraints, such as departure and arrival constraints, plume impingement constraints, and structural constraints. The main purpose of the system is to present the trajectory and the constraints in an easily interpretable graphical format. Through a graphical interactive process, the trajectory waypoints are edited until all operational constraints are satisfied. A series of experiments was conducted to evaluate the system. Eight airline pilots with no prior background in orbital mechanics participated in the experiments. Subject training included a stand-alone training session of about 6 hours duration, in which the subjects became familiar with orbital mechanics concepts and performed a series of exercises to familiarize themselves with the control and display features of the system. They then carried out a series of production runs in which 90 different trajectory design situations were randomly addressed. The purpose of these experiments was to investigate how the planning time, planning efforts, and fuel expenditures were affected by the planning difficulty. Some results of these experiments are presented.

  10. Selective proximal vagotomy with and without pyloroplasty

    International Nuclear Information System (INIS)

    Brodersen, E.

    1984-01-01

    It was the aim of the study described here to gain information relevant to the well-being of patients subjected to selective proximal vagotomy with or without pyroloplasty as soon as possible after surgery. For this purpose, particular care was taken to ascertain the frequency of recidivation and the post-operative occurrence of disturbances in the emptying of gastric contents. In 35 patients solely undergoing SPV and a further 12 individuals, where both SPV and pyroloplasty had been performed, gastric emptying was monitored using a gamma camera and computer system. All patients were given a standardised test meal consisting of 500 ml ready-made milk labeled with 2 mCi 99mTc-HSA. After the patients had been assigned to different study groups according to the gastric emptying rates established in the individual cases, it became evident that there was a correlation between gastric emptying time (T/2) and the occurrence of post-operative discomfort. In the majority of patients the gastric emptying rate was found to be increased as compared to individuals with a healthy stomach. Among a total of 8 patients showing delayed gastric emptying only one, who solely underwent SPV, reported post-operative discomfort. Markedly increased rates of gastric emptying (T/2 ≤ 5 min) were predominantly determined in patients subjected to SPV in conjunction with pyroloplasty. A dumping syndrome and diarrhea were diagnosed in every third patient. Clinical follow-up studies and questionnaires distributed among the study patients showed relapses to occur with a frequency of 6.7%, the recidivation of ulcera being confined to the group of patients merely undergoing SPV. (TRV) [de

  11. Nanocrystal Bioassembly: Asymmetry, Proximity, and Enzymatic Manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Claridge, Shelley A. [Univ. of California, Berkeley, CA (United States)

    2008-05-01

    Research at the interface between biomolecules and inorganic nanocrystals has resulted in a great number of new discoveries. In part this arises from the synergistic duality of the system: biomolecules may act as self-assembly agents for organizing inorganic nanocrystals into functional materials; alternatively, nanocrystals may act as microscopic or spectroscopic labels for elucidating the behavior of complex biomolecular systems. However, success in either of these functions relies heavily uponthe ability to control the conjugation and assembly processes.In the work presented here, we first design a branched DNA scaffold which allows hybridization of DNA-nanocrystal monoconjugates to form discrete assemblies. Importantly, the asymmetry of the branched scaffold allows the formation of asymmetric2assemblies of nanocrystals. In the context of a self-assembled device, this can be considered a step toward the ability to engineer functionally distinct inputs and outputs.Next we develop an anion-exchange high performance liquid chromatography purification method which allows large gold nanocrystals attached to single strands of very short DNA to be purified. When two such complementary conjugates are hybridized, the large nanocrystals are brought into close proximity, allowing their plasmon resonances to couple. Such plasmon-coupled constructs are of interest both as optical interconnects for nanoscale devices and as `plasmon ruler? biomolecular probes.We then present an enzymatic ligation strategy for creating multi-nanoparticle building blocks for self-assembly. In constructing a nanoscale device, such a strategy would allow pre-assembly and purification of components; these constructs can also act as multi-label probes of single-stranded DNA conformational dynamics. Finally we demonstrate a simple proof-of-concept of a nanoparticle analog of the polymerase chain reaction.

  12. Proximally exposed A-bomb survivors. 2

    International Nuclear Information System (INIS)

    Kamada, Nanao

    1992-01-01

    Methods for observing chromosomes can be chronologically divided into the era of non-differential staining technique (1962-1975) and the era of differential staining method (since 1976). This paper reviews the literature of chromosomal aberrations in bone marrow cells found in the two eras. Findings during the era of 1962-1975 include the frequency of chromosomal aberrations in bone marrow cells, comparison of chromosomal aberrations in bone marrow cells and T lymphocytes, and annual variation of chromosomal aberrations. The frequency of chromosomal aberrations was high in proximally exposed A-bomb survivors (90.5% and 52.6% in A-bomb survivors exposed within 500 m and at 501-1,000 m, respectively); on the contrary, it was low in those exposed far from 1,000 m (6.2% or less). The frequency of chromosomal aberrations in bone marrow cells was lower than that in T lymphocytes (21.5% vs 27.1% in those exposed within 500 m and 14.1% vs 23% in those exposed at 501-1,000 m). Annual analysis for chromosomal aberrations has shown the somewhat dependence upon medullary hematopoiesis and virus infection. The advent of differential staining technique since 1976 has made it possible to clarify the type of chromosomal aberrations and site of breakage. Of 710 bone marrow cells taken from 13 A-bomb survivors exposed within 1,000 m, 121 cells (from 11 A-bomb survivors) exhibited chromosomal aberrations. In differential staining analysis, all 121 cells but one were found to be of stable type, such as translocation and inversion. Furthermore, the site of breakage was found to be non-randomly distributed. Analysis of chromosomal aberrations in bone marrow cells has advantages of reflecting dynamic condition of these cells and determining gradual progression into leukemia. (N.K.)

  13. Hypospadias and residential proximity to pesticide applications.

    Science.gov (United States)

    Carmichael, Suzan L; Yang, Wei; Roberts, Eric M; Kegley, Susan E; Wolff, Craig; Guo, Liang; Lammer, Edward J; English, Paul; Shaw, Gary M

    2013-11-01

    Experimental evidence suggests pesticides may be associated with hypospadias. Examine the association of hypospadias with residential proximity to commercial agricultural pesticide applications. The study population included male infants born from 1991 to 2004 to mothers residing in 8 California counties. Cases (n = 690) were ascertained by the California Birth Defects Monitoring Program; controls were selected randomly from the birth population (n = 2195). We determined early pregnancy exposure to pesticide applications within a 500-m radius of mother's residential address, using detailed data on applications and land use. Associations with exposures to physicochemical groups of pesticides and specific chemicals were assessed using logistic regression adjusted for maternal race or ethnicity and age and infant birth year. Forty-one percent of cases and controls were classified as exposed to 57 chemical groups and 292 chemicals. Despite >500 statistical comparisons, there were few elevated odds ratios with confidence intervals that excluded 1 for chemical groups or specific chemicals. Those that did were for monochlorophenoxy acid or ester herbicides; the insecticides aldicarb, dimethoate, phorate, and petroleum oils; and adjuvant polyoxyethylene sorbitol among all cases; 2,6-dinitroaniline herbicides, the herbicide oxyfluorfen, and the fungicide copper sulfate among mild cases; and chloroacetanilide herbicides, polyalkyloxy compounds used as adjuvants, the insecticides aldicarb and acephate, and the adjuvant nonyl-phenoxy-poly(ethylene oxy)ethanol among moderate and severe cases. Odds ratios ranged from 1.9 to 2.9. Most pesticides were not associated with elevated hypospadias risk. For the few that were associated, results should be interpreted with caution until replicated in other study populations.

  14. Ligament augmentation for prevention of proximal junctional kyphosis and proximal junctional failure in adult spinal deformity.

    Science.gov (United States)

    Safaee, Michael M; Deviren, Vedat; Dalle Ore, Cecilia; Scheer, Justin K; Lau, Darryl; Osorio, Joseph A; Nicholls, Fred; Ames, Christopher P

    2018-05-01

    OBJECTIVE Proximal junctional kyphosis (PJK) is a well-recognized, yet incompletely defined, complication of adult spinal deformity surgery. There is no standardized definition for PJK, but most studies describe PJK as an increase in the proximal junctional angle (PJA) of greater than 10°-20°. Ligament augmentation is a novel strategy for PJK reduction that provides strength to the upper instrumented vertebra (UIV) and adjacent segments while also reducing junctional stress at those levels. METHODS In this study, ligament augmentation was used in a consecutive series of adult spinal deformity patients at a single institution. Patient demographics, including age; sex; indication for surgery; revision surgery; surgical approach; and use of 3-column osteotomies, vertebroplasty, or hook fixation at the UIV, were collected. The PJA was measured preoperatively and at last follow-up using 36-inch radiographs. Data on change in PJA and need for revision surgery were collected. Univariate and multivariate analyses were performed to identify factors associated with change in PJA and proximal junctional failure (PJF), defined as PJK requiring surgical correction. RESULTS A total of 200 consecutive patients were included: 100 patients before implementation of ligament augmentation and 100 patients after implementation of this technique. The mean age of the ligament augmentation cohort was 66 years, and 67% of patients were women. Over half of these cases (51%) were revision surgeries, with 38% involving a combined anterior or lateral and posterior approach. The mean change in PJA was 6° in the ligament augmentation group compared with 14° in the control group (p historical cohort, ligament augmentation is associated with a significant decrease in PJK and PJF. These data support the implementation of ligament augmentation in surgery for adult spinal deformity, particularly in patients with a high risk of developing PJK and PJF.

  15. Novel Biosensor of Membrane Protein Proximity Based on Fluorogen Activated Proteins.

    Science.gov (United States)

    Vasilev, Kalin V; Gallo, Eugenio; Shank, Nathaniel; Jarvik, Jonathan W

    2016-01-01

    We describe a novel biosensor system for reporting proximity between cell surface proteins in live cultured cells. The biosensor takes advantage of recently developed fluorogen-activating proteins (FAPs) that display fluorescence only when bound to otherwise-nonfluorescent fluorogen molecules. To demonstrate feasibility for the approach, two recombinant rapamycin-binding proteins were expressed as single-pass plasma membrane proteins in HeLa cells; one of the proteins (scAvd- FRB) carried an extracellular avidin tag; the other (HL1-TO1-FKBP) carried an extracellular FAP. Cells were incubated with a membrane-impermeable bivalent ligand (biotin-PEG2000-DIR) consisting of biotin joined to a dimethyl-indole red (DIR) fluorogen by a polyethylene glycol linker, thus tethering the fluorogen to the scAvd-FRB fusion protein. Addition of rapamycin, which promotes FKBP-FRB dimerization and thereby brings the FAP in close proximity to the tethered fluorogen, led to a significant increase in DIR fluorescence. We call the new proximity assay TEFLA, for tethered fluorogen assay.

  16. Cancer rates after the Three Mile Island nuclear accident and proximity of residence to the plant.

    Science.gov (United States)

    Hatch, M C; Wallenstein, S; Beyea, J; Nieves, J W; Susser, M

    1991-06-01

    In the light of a possible link between stress and cancer promotion or progression, and of previously reported distress in residents near the Three Mile Island (TMI) nuclear power plant, we attempted to evaluate the impact of the March 1979 accident on community cancer rates. Proximity of residence to the plant, which related to distress in previous studies, was taken as a possible indicator of accident stress; the postaccident pattern in cancer rates was examined in 69 "study tracts" within a 10-mile radius of TMI, in relation to residential proximity. A modest association was found between postaccident cancer rates and proximity (OR = 1.4; 95% CI = 1.3, 1.6). After adjusting for a gradient in cancer risk prior to the accident, the odds ratio contrasting those closest to the plant with those living farther out was 1.2 (95% CI = 1.0, 1.4). A postaccident increase in cancer rates near the Three Mile Island plant was notable in 1982, persisted for another year, and then declined. Radiation emissions, as modeled mathematically, did not account for the observed increase. Interpretation in terms of accident stress is limited by the lack of an individual measure of stress and by uncertainty about whether stress has a biological effect on cancer in humans. An alternative mechanism for the cancer increase near the plant is through changes in care-seeking and diagnostic practice arising from postaccident concern.

  17. Treatment of Unstable Trochanteric Femur Fractures: Proximal Femur Nail Versus Proximal Femur Locking Compression Plate.

    Science.gov (United States)

    Singh, Ashutosh Kumar; Narsaria, Nidi; G R, Arun; Srivastava, Vivek

    Unstable trochanteric femur fractures are common fractures that are difficult to manage. We conducted a prospective study to compare functional outcomes and complications of 2 different implant designs, proximal femur nail (PFN) and proximal femur locking compression plate (PFLCP), used in internal fixation of unstable trochanteric femur fractures. On hospital admission, 48 patients with unstable trochanteric fractures were randomly assigned (using a sealed envelope method) to treatment with either PFN (24 patients) or PFLCP (24 patients). Perioperative data and complications were recorded. All cases were followed up for 2 years. The groups did not differ significantly (P > .05) in operative time, reduction quality, complications, hospital length of stay, union rate, or time to union. Compared with the PFLCP group, the PFN group had shorter incisions and less blood loss. Regarding functional outcomes, there was no significant difference in mean Harris Hip Score (P = .48) or Palmer and Parker mobility score (P = .58). Both PFN and PFLCP are effective in internal fixation of unstable trochanteric femur fractures.

  18. Dual pathology proximal median nerve compression of the forearm.

    LENUS (Irish Health Repository)

    Murphy, Siun M

    2013-12-01

    We report an unusual case of synchronous pathology in the forearm- the coexistence of a large lipoma of the median nerve together with an osteochondroma of the proximal ulna, giving rise to a dual proximal median nerve compression. Proximal median nerve compression neuropathies in the forearm are uncommon compared to the prevalence of distal compression neuropathies (eg Carpal Tunnel Syndrome). Both neural fibrolipomas (Refs. 1,2) and osteochondromas of the proximal ulna (Ref. 3) in isolation are rare but well documented. Unlike that of a distal compression, a proximal compression of the median nerve will often have a definite cause. Neural fibrolipoma, also called fibrolipomatous hamartoma are rare, slow-growing, benign tumours of peripheral nerves, most often occurring in the median nerve of younger patients. To our knowledge, this is the first report of such dual pathology in the same forearm, giving rise to a severe proximal compression of the median nerve. In this case, the nerve was being pushed anteriorly by the osteochondroma, and was being compressed from within by the intraneural lipoma. This unusual case highlights the advantage of preoperative imaging as part of the workup of proximal median nerve compression.

  19. Dual pathology proximal median nerve compression of the forearm.

    Science.gov (United States)

    Murphy, Siun M; Browne, Katherine; Tuite, David J; O'Shaughnessy, Michael

    2013-12-01

    We report an unusual case of synchronous pathology in the forearm- the coexistence of a large lipoma of the median nerve together with an osteochondroma of the proximal ulna, giving rise to a dual proximal median nerve compression. Proximal median nerve compression neuropathies in the forearm are uncommon compared to the prevalence of distal compression neuropathies (eg Carpal Tunnel Syndrome). Both neural fibrolipomas (Refs. 1,2) and osteochondromas of the proximal ulna (Ref. 3) in isolation are rare but well documented. Unlike that of a distal compression, a proximal compression of the median nerve will often have a definite cause. Neural fibrolipoma, also called fibrolipomatous hamartoma are rare, slow-growing, benign tumours of peripheral nerves, most often occurring in the median nerve of younger patients. To our knowledge, this is the first report of such dual pathology in the same forearm, giving rise to a severe proximal compression of the median nerve. In this case, the nerve was being pushed anteriorly by the osteochondroma, and was being compressed from within by the intraneural lipoma. This unusual case highlights the advantage of preoperative imaging as part of the workup of proximal median nerve compression. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  20. Digital contrast subtraction radiography for proximal caries diagnosis

    International Nuclear Information System (INIS)

    Kang, Byung Cheol; Yoon, Suk Ja

    2002-01-01

    To determine whether subtraction images utilizing contrast media can improve the diagnostic performance of proximal caries diagnosis compared to conventional periapical radiographic images. Thirty-six teeth with 57 proximal surfaces were radiographied using a size no.2 RVG-ui sensor (Trophy Radiology, Marne-la-Vallee, France). The teeth immersed in water-soluble contrast media and subtraction images were taken. Each tooth was then sectioned for histologic examination. The digital radiographic images and subtraction images were examined and interpreted by three dentists for proximal caries. The results of the proximal caries diagnosis were then verified with the results of the histologic examination. The proximal caries sensitivity using digital subtraction radiography was significantly higher than simply examining a single digital radiograph. The sensitivity of the proximal dentinal carious lesion when analyzed with the subtraction radiograph and the radiograph together was higher than with the subtraction radiograph or the radiograph alone. The use of subtraction radiography with contrast media may be useful for detecting proximal dentinal carious lesions.

  1. Effect of age on proximal esophageal response to swallowing

    Directory of Open Access Journals (Sweden)

    Roberto Oliveira Dantas

    2010-12-01

    Full Text Available CONTEXT: It has been demonstrated that the ageing process affects esophageal motility. OBJECTIVES: To evaluate the effect of the age on the proximal esophageal response to wet swallows. METHOD: We measured the proximal esophageal response to swallows of a 5 mL bolus of water in 69 healthy volunteers, 20 of them aged 18-30 years (group I, 27 aged 31-50 years (group II, and 22 aged 51-74 years (group III. We used the manometric method with continuous perfusion. The proximal esophageal contractions were recorded 5 cm from a pharyngeal recording site located 1 cm above the upper esophageal sphincter. The time between the onset of the pharyngeal and of the proximal esophageal recording (pharyngeal-esophageal time and the amplitude, duration and area under the curve of the proximal esophageal contraction were measured. RESULTS: The pharyngeal-esophageal time was shorter in group I subjects than in group II and III subjects (P<0.05. The duration of proximal esophageal contractions was longer in group I than in groups II and III (P<0.001. There was no differences between groups in the amplitude or area under the curve of contractions. There were no differences between groups II and III for any of the measurements. CONCLUSION: We conclude that the age may affects the response of the proximal esophagus to wet swallows.

  2. Giant proximity effect and critical opalescence in EuS

    Science.gov (United States)

    Charlton, Timothy; Ramos, Silvia; Quintanilla, Jorge; Suter, Andreas; Moodera, Jagadeesh

    2015-03-01

    The proximity effect is a type of wetting phenomenon where an ordered state, usually magnetism or superconductivity, ``leaks'' from one material into an adjacent one over some finite distance. For superconductors, the characteristic range is of the order of the coherence length, usually hundreds of nm. Nevertheless much longer, ``giant'' proximity effects have been observed in cuprate perovskite junctions. Such giant proximity effects can be understood by taking into account the divergence of the pairing susceptibility in the non-superconducting material when it is itself close to a superconducting instability: a superconducting version of critical opalescence. Since critical opalescence occurs in all second order phase transitions, giant proximity effects are expected to be general, therefor there must be a giant ferromagnetic proximity effect. Compared to its superconducting counterpart, the giant ferromagnetic proximity effect has the advantage that the order parameter (magnetization) can be observed directly. We have fabricated Co/EuS thin films and measured the magnetization profiles as a function of temperature using the complementary techniques of low energy muon relaxation and polarized neutron reflectivity. Details of the proximity effect near TCEuS will be presented.

  3. Cancer in proximity to TV towers

    International Nuclear Information System (INIS)

    Hocking, B.; Gordon, I.; Hatfield, G.

    1996-01-01

    Standard (AS2772.1). The few actual measurements available indicate even lower levels. The analysis shows no increased risk of brain cancer. An increased risk of childhood leukaemia is indicated in the municipalities close to the TV towers. The rate ratio for incidence is 1.6 (95% Cl: 1.08-2 41) and for mortality is 2.25 (95% Cl: 1.29-3.92), mainly due to lymphatic leukaemia (1.63 for incidence, 2.84 for mortality). An association between increased childhood leukaemia and proximity to TV towers is indicated. Further studies are needed to test this association and determine any dose-response relationship before firm conclusions may be reached

  4. Reoperations following proximal interphalangeal joint nonconstrained arthroplasties.

    Science.gov (United States)

    Pritsch, Tamir; Rizzo, Marco

    2011-09-01

    To retrospectively analyze the reasons for reoperations following primary nonconstrained proximal interphalangeal (PIP) joint arthroplasty and review clinical outcomes in this group of patients with 1 or more reoperations. Between 2001 and 2009, 294 nonconstrained (203 pyrocarbon and 91 metal-plastic) PIP joint replacements were performed in our institution. A total of 76 fingers (59 patients) required reoperation (50 pyrocarbon and 26 metal-plastic). There were 40 women and 19 men with an average age of 51 years (range, 19-83 y). Primary diagnoses included osteoarthritis in 35, posttraumatic arthritis in 24, and inflammatory arthritis in 17 patients. There were 21 index, 27 middle, 18 ring, and 10 small fingers. The average number of reoperations per PIP joint was 1.6 (range, 1-4). A total of 45 joints had 1 reoperation, 19 had 2, 11 had 3, and 1 had 4. Extensor mechanism dysfunction was the most common reason for reoperation; it involved 51 of 76 fingers and was associated with Chamay or tendon-reflecting surgical approaches. Additional etiologies included component loosening in 17, collateral ligament failure in 10, and volar plate contracture in 8 cases. Inflammatory arthritis was associated with collateral ligament failure. Six fingers were eventually amputated, 9 had PIP joint arthrodeses, and 2 had resection arthroplasties. The arthrodesis and amputation rates correlated with the increased number of reoperations per finger. Clinically, most patients had no or mild pain at the most recent follow-up, and the PIP joint range-of-motion was not significantly different from preoperative values. Pain levels improved with longer follow-up. Reoperations following primary nonconstrained PIP joint arthroplasties are common. Extensor mechanism dysfunction was the most common reason for reoperation. The average reoperation rate was 1.6, and arthrodesis and amputation are associated with an increasing number of operations. Overall clinical outcomes demonstrated no

  5. Proximal caries detection: Sirona Sidexis versus Kodak Ektaspeed Plus.

    Science.gov (United States)

    Khan, Emad A; Tyndall, Donald A; Ludlow, John B; Caplan, Daniel

    2005-01-01

    This study compared the accuracy of intraoral film and a charge-coupled device (CCD) receptor for proximal caries detection. Four observers evaluated images of the proximal surfaces of 40 extracted posterior teeth. The presence or absence of caries was scored using a five-point confidence scale. The actual status of each surface was determined from ground section histology. Responses were evaluated by means of receiver operating characteristic (ROC) analysis. Areas under ROC curves (Az) were assessed through a paired t-test. The performance of the CCD-based intraoral sensor was not different statistically from Ektaspeed Plus film in detecting proximal caries.

  6. [Avulsion of the Proximal Hamstring Insertion. Case Reports].

    Science.gov (United States)

    Mizera, R; Harcuba, R; Kratochvíl, J

    2016-01-01

    Proximal hamstring avulsion is an uncommon muscle injury with a lack of consensus on indications and the timing and technique of surgery. Poor clinical symptoms and difficulties in the diagnostic process can lead to a false diagnosis. The authors present three cases of proximal hamstring avulsion, two complete and one partial ruptures of the biceps femoris muscle. MRI and ultrasound scans were used for optimal treatment alignment. Acute surgery reconstruction (hamstring strength. Two interesting systematic reviews published on the treatment of proximal hamstring avulsion are discussed in the final part of the paper. Key words: hamstring, rupture, avulsion.

  7. Functional analysis of human and chimpanzee promoters.

    Science.gov (United States)

    Heissig, Florian; Krause, Johannes; Bryk, Jaroslaw; Khaitovich, Philipp; Enard, Wolfgang; Pääbo, Svante

    2005-01-01

    It has long been argued that changes in gene expression may provide an additional and crucial perspective on the evolutionary differences between humans and chimpanzees. To investigate how often expression differences seen in tissues are caused by sequence differences in the proximal promoters, we tested the expression activity in cultured cells of human and chimpanzee promoters from genes that differ in mRNA expression between human and chimpanzee tissues. Twelve promoters for which the corresponding gene had been shown to be differentially expressed between humans and chimpanzees in liver or brain were tested. Seven showed a significant difference in activity between the human promoter and the orthologous chimpanzee promoter in at least one of the two cell lines used. However, only three of them showed a difference in the same direction as in the tissues. Differences in proximal promoter activity are likely to be common between humans and chimpanzees, but are not linked in a simple fashion to gene-expression levels in tissues. This suggests that several genetic differences between humans and chimpanzees might be responsible for a single expression difference and thus that relevant expression differences between humans and chimpanzees will be difficult to predict from cell culture experiments or DNA sequences.

  8. Proximity effects of high voltage electric power transmission lines on ...

    African Journals Online (AJOL)

    Yomi

    2010-08-18

    Aug 18, 2010 ... transmission lines on ornamental plant growth. Zeki Demir ... The effects of proximity to power-line on specific leaf area and seedling dbh were tested .... during vegetation season is about 72% and common wind blow.

  9. Nutritive Value Assessment of Four Crop Residues by Proximate ...

    African Journals Online (AJOL)

    Dr Grace Tona

    Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, Nigeria ... Abstract. This study estimated the proximate composition and in vitro gas production parameters of rice husk, bean ... farms and industries generate large quantities.

  10. Computational proximity excursions in the topology of digital images

    CERN Document Server

    Peters, James F

    2016-01-01

    This book introduces computational proximity (CP) as an algorithmic approach to finding nonempty sets of points that are either close to each other or far apart. Typically in computational proximity, the book starts with some form of proximity space (topological space equipped with a proximity relation) that has an inherent geometry. In CP, two types of near sets are considered, namely, spatially near sets and descriptivelynear sets. It is shown that connectedness, boundedness, mesh nerves, convexity, shapes and shape theory are principal topics in the study of nearness and separation of physical aswell as abstract sets. CP has a hefty visual content. Applications of CP in computer vision, multimedia, brain activity, biology, social networks, and cosmology are included. The book has been derived from the lectures of the author in a graduate course on the topology of digital images taught over the past several years. Many of the students have provided important insights and valuable suggestions. The topics in ...

  11. Population Exposure Estimates in Proximity to Nuclear Power Plants, Locations

    Data.gov (United States)

    National Aeronautics and Space Administration — The Population Exposure Estimates in Proximity to Nuclear Power Plants, Locations data set combines information from a global data set developed by Declan Butler of...

  12. Proximate composition and nutrient content of some wild and ...

    African Journals Online (AJOL)

    Proximate composition and nutrient content of some wild and cultivated ... Ca, P, K), one minor mineral (Fe) constituent and vitamin C content were determined. ... Mineral content (P and K) in the mushroom sporophores were found to be ...

  13. Effects of Fermentation and Extrusion on the Proximate Composition ...

    African Journals Online (AJOL)

    Prof. Ogunji

    protein malnutrition persists as a principal health problem among children .... Proximate analysis: Moisture content ... nitrogen by a factor of 6.25. Crude fat ... Statistical analysis: The data were ..... interaction of amino acid in maillard reactions.

  14. Proximate composition and mineral contents of Pebbly fish, Alestes ...

    African Journals Online (AJOL)

    ACSS

    /100 g) were significantly .... Proximate analysis of A. baremoze fillets according to sample sizes in a study in. Uganda .... present in the fish tissues in trace amounts. ... The zinc contents in fish samples of ..... (mercury, cadmium, lead, tin and.

  15. Effects of Planting Locations on the Proximate Compositions of ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Ash, moisture, crude fat, crude fibre, carbohydrate and protein contents were determined according ... All fruits, vegetables, legumes (beans and peas), and the grains we eat ... isolate and quantify each proximate present in the plant material.

  16. Inexact proximal Newton methods for self-concordant functions

    DEFF Research Database (Denmark)

    Li, Jinchao; Andersen, Martin Skovgaard; Vandenberghe, Lieven

    2016-01-01

    with an application to L1-regularized covariance selection, in which prior constraints on the sparsity pattern of the inverse covariance matrix are imposed. In the numerical experiments the proximal Newton steps are computed by an accelerated proximal gradient method, and multifrontal algorithms for positive definite...... matrices with chordal sparsity patterns are used to evaluate gradients and matrix-vector products with the Hessian of the smooth component of the objective....

  17. Hemiarthroplasty for proximal humeral fracture: restoration of the Gothic arch.

    Science.gov (United States)

    Krishnan, Sumant G; Bennion, Phillip W; Reineck, John R; Burkhead, Wayne Z

    2008-10-01

    Proximal humerus fractures are the most common fractures of the shoulder girdle, and initial management of these injuries often determines final outcome. When arthroplasty is used to manage proximal humeral fractures, surgery remains technically demanding, and outcomes have been unpredictable. Recent advances in both technique and prosthetic implants have led to more successful and reproducible results. Key technical points include restoration of the Gothic arch, anatomic tuberosity reconstruction, and minimal soft tissue dissection.

  18. The IL-17F/IL-17RC Axis Promotes Respiratory Allergy in the Proximal Airways

    Directory of Open Access Journals (Sweden)

    Antonella De Luca

    2017-08-01

    Full Text Available The interleukin 17 (IL-17 cytokine and receptor family is central to antimicrobial resistance and inflammation in the lung. Mice lacking IL-17A, IL-17F, or the IL-17RA subunit were compared with wild-type mice for susceptibility to airway inflammation in models of infection and allergy. Signaling through IL-17RA was required for efficient microbial clearance and prevention of allergy; in the absence of IL-17RA, signaling through IL-17RC on epithelial cells, predominantly by IL-17F, significantly exacerbated lower airway Aspergillus or Pseudomonas infection and allergic airway inflammation. In contrast, following infection with the upper respiratory pathogen Staphylococcus aureus, the IL-17F/IL-17RC axis mediated protection. Thus, IL-17A and IL-17F exert distinct biological effects during pulmonary infection; the IL-17F/IL-17RC signaling axis has the potential to significantly worsen pathogen-associated inflammation of the lower respiratory tract in particular, and should be investigated further as a therapeutic target for treating pathological inflammation in the lung.

  19. PHF8 and REST/NRSF co-occupy gene promoters to regulate proximal gene expression

    OpenAIRE

    Wang, Juan; Lin, Xueqiu; Wang, Su; Wang, Chenfei; Wang, Qixuan; Duan, Xikun; Lu, Peng; Wang, Qian; Wang, Chengyang; Liu, X. Shirley; Huang, Jinyan

    2014-01-01

    Chromatin regulators play an important role in the development of human diseases. In this study, we focused on Plant Homeo Domain Finger protein 8 (PHF8), a chromatin regulator that has attracted special concern recently. PHF8 is a histone lysine demethylase ubiquitously expressed in nuclei. Mutations of PHF8 are associated with X-linked mental retardation. It usually functions as a transcriptional co-activator by associating with H3K4me3 and RNA polymerase II. We found that PHF8 may associat...

  20. Psychological responses to the proximity of climate change

    Science.gov (United States)

    Brügger, Adrian; Dessai, Suraje; Devine-Wright, Patrick; Morton, Thomas A.; Pidgeon, Nicholas F.

    2015-12-01

    A frequent suggestion to increase individuals' willingness to take action on climate change and to support relevant policies is to highlight its proximal consequences, that is, those that are close in space and time. But previous studies that have tested this proximizing approach have not revealed the expected positive effects on individual action and support for addressing climate change. We present three lines of psychological reasoning that provide compelling arguments as to why highlighting proximal impacts of climate change might not be as effective a way to increase individual mitigation and adaptation efforts as is often assumed. Our contextualization of the proximizing approach within established psychological research suggests that, depending on the particular theoretical perspective one takes on this issue, and on specific individual characteristics suggested by these perspectives, proximizing can bring about the intended positive effects, can have no (visible) effect or can even backfire. Thus, the effects of proximizing are much more complex than is commonly assumed. Revealing this complexity contributes to a refined theoretical understanding of the role that psychological distance plays in the context of climate change and opens up further avenues for future research and for interventions.

  1. HEMATOMA OF THE PROXIMAL NAIL FOLD. REPORT OF 41 CASES

    Directory of Open Access Journals (Sweden)

    Chang Patricia

    2011-04-01

    Full Text Available Background: The proximal fold is an important part of the nail apparatus it contributes to the formation of the nail plate and through the cuticle acts as an impermeable barrier protecting it from any cause.Objective: To know the proximal nail fold hematoma caused by the use of pulse oximeter.Material and Methods: A descriptive study was conducted in 41 patients with proximal nail hematoma secondary to the use of oximetry in patients hospitalized in the Intermediate and Intensive Care Unit at the Hospital General de Enfermedades from December 1, 2007 to December 31, 2010.Results: We studied 41 patients with proximal nail fold hematoma secondary to the use of oximeter, 30 (73.1% were males and 11 (26.8% females. The numbers of fingers affected by pulse oximeter were in one digit. 30 (73.1% cases, in two digits 6 (14.6%, in three digits 3 (7.3%, in 4 digits 1 (2.4% and in 5 digits 1 (2.4% case. The most affected proximal nail fold was right index: 24 (58.5%, right middle 11 (26.8%, right ring 6 (14.6%, left index 12 (29.2%, and left middle 6 (14.6% cases.Conclusions: Hematomas of the proximal nail fold may be caused by different traumatisms. The use of pulse oximeter is one of them.

  2. Health promotion.

    Science.gov (United States)

    Miyake, S; Lucas-Miyake, M

    1989-01-01

    This article will describe a marketing model for the development of a role for occupational therapy in the industrial market. Health promotion activities are used as a means to diversify existing revenue bases by establishing new referral sources in industry. The technique of need satisfaction -selling or marketing one's services to a customer based on needs expressed by the customer - is reviewed, and implementation of this approach is described from two settings, one in psychiatry and the other in rehabilitation.

  3. IGFBP3 Promoter Methylation in Colorectal Cancer: Relationship with Microsatellite Instability, CpG Island Methylator Phenotype, p53

    Directory of Open Access Journals (Sweden)

    Takako Kawasaki

    2007-12-01

    Full Text Available Insulin-like growth factor binding protein 3 (IGFBP3, which is induced by wild-type p53, regulates IGF and interacts with the TGF-β pathway. IGFBP3 promoter methylation may occur in colorectal cancer with or without the CpG island methylator phenotype (CIMP, which is associated with microsatellite instability (MSI and TGFBR2 mutation. We examined the relationship between IGFBP3 methylation, p53 expression, CIMP and MSI in 902 population-based colorectal cancers. Utilizing real-time PCR (MethyLight, we quantified promoter methylation in IGFBP3 and eight other CIMP-high-specific promoters (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1. IGFBP3 methylation was far more frequent in non-MSI-high CIMP-high tumors (85% = 35/41 than in MSI-high CIMPhigh (49% = 44/90, P < .0001, MSI-high non-CIMP-high (17% = 6/36, P < .0001, non-MSI-high non-CIMP-high tumors (22% = 152/680, P < .0001. Among CIMPhigh tumors, the inverse relationship between MSI and IGFBP3 methylation persisted in p53-negative tumors (P < .0001, but not in p53-positive tumors. IGFBP3 methylation was associated inversely with TGFBR2 mutation in MSI-high non-CIMP-high tumors (P = .02. In conclusion, IGFBP3 methylation is inversely associated with MSI in CIMP-high colorectal cancers, this relationship is limited to p53-negative tumors. Our data suggest complex relationship between global genomic/epigenomic phenomena (such as MSI/ CIMP, single molecular events (e.g., IGFBP3 methylation, TP53 mutation, TGFBR2 mutation, the related pathways.

  4. Promoter Hypermethylation Profiling Identifies Subtypes of Head and Neck Cancer with Distinct Viral, Environmental, Genetic and Survival Characteristics.

    Directory of Open Access Journals (Sweden)

    Javed Hussain Choudhury

    Full Text Available Epigenetic and genetic alteration plays a major role to the development of head and neck squamous cell carcinoma (HNSCC. Consumption of tobacco (smoking/chewing and human papilloma virus (HPV are also associated with an increase the risk of HNSCC. Promoter hypermethylation of the tumor suppression genes is related with transcriptional inactivation and loss of gene expression. We investigated epigenetic alteration (promoter methylation of tumor-related genes/loci in tumor tissues in the context of genetic alteration, viral infection, and tobacco exposure and survival status.The study included 116 tissue samples (71 tumor and 45 normal tissues from the Northeast Indian population. Methylation specific polymerase chain reaction (MSP was used to determine the methylation status of 10 tumor-related genes/loci (p16, DAPK, RASSF1, BRAC1, GSTP1, ECAD, MLH1, MINT1, MINT2 and MINT31. Polymorphisms of CYP1A1, GST (M1 & T1, XRCC1and XRCC2 genes were studied by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP and multiplex-PCR respectively.Unsupervised hierarchical clustering analysis based on methylation pattern had identified two tumor clusters, which significantly differ by CpG island methylator phenotype (CIMP, tobacco, GSTM1, CYP1A1, HPV and survival status. Analyzing methylation of genes/loci individually, we have found significant higher methylation of DAPK, RASSF1, p16 and MINT31 genes (P = 0.031, 0.013, 0.031 and 0.015 respectively in HPV (+ cases compared to HPV (-. Furthermore, a CIMP-high and Cluster-1 characteristic was also associated with poor survival.Promoter methylation profiles reflecting a correlation with tobacco, HPV, survival status and genetic alteration and may act as a marker to determine subtypes and patient outcome in HNSCC.

  5. Promoter Hypermethylation Profiling Identifies Subtypes of Head and Neck Cancer with Distinct Viral, Environmental, Genetic and Survival Characteristics

    Science.gov (United States)

    Choudhury, Javed Hussain; Ghosh, Sankar Kumar

    2015-01-01

    Background Epigenetic and genetic alteration plays a major role to the development of head and neck squamous cell carcinoma (HNSCC). Consumption of tobacco (smoking/chewing) and human papilloma virus (HPV) are also associated with an increase the risk of HNSCC. Promoter hypermethylation of the tumor suppression genes is related with transcriptional inactivation and loss of gene expression. We investigated epigenetic alteration (promoter methylation of tumor-related genes/loci) in tumor tissues in the context of genetic alteration, viral infection, and tobacco exposure and survival status. Methodology The study included 116 tissue samples (71 tumor and 45 normal tissues) from the Northeast Indian population. Methylation specific polymerase chain reaction (MSP) was used to determine the methylation status of 10 tumor-related genes/loci (p16, DAPK, RASSF1, BRAC1, GSTP1, ECAD, MLH1, MINT1, MINT2 and MINT31). Polymorphisms of CYP1A1, GST (M1 & T1), XRCC1and XRCC2 genes were studied by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and multiplex-PCR respectively. Principal Findings Unsupervised hierarchical clustering analysis based on methylation pattern had identified two tumor clusters, which significantly differ by CpG island methylator phenotype (CIMP), tobacco, GSTM1, CYP1A1, HPV and survival status. Analyzing methylation of genes/loci individually, we have found significant higher methylation of DAPK, RASSF1, p16 and MINT31genes (P = 0.031, 0.013, 0.031 and 0.015 respectively) in HPV (+) cases compared to HPV (-). Furthermore, a CIMP-high and Cluster-1 characteristic was also associated with poor survival. Conclusions Promoter methylation profiles reflecting a correlation with tobacco, HPV, survival status and genetic alteration and may act as a marker to determine subtypes and patient outcome in HNSCC. PMID:26098903

  6. Comparative analyses of bidirectional promoters in vertebrates

    Directory of Open Access Journals (Sweden)

    Taylor James

    2008-05-01

    Full Text Available Abstract Background Orthologous genes with deep phylogenetic histories are likely to retain similar regulatory features. In this report we utilize orthology assignments for pairs of genes co-regulated by bidirectional promoters to map the ancestral history of the promoter regions. Results Our mapping of bidirectional promoters from humans to fish shows that many such promoters emerged after the divergence of chickens and fish. Furthermore, annotations of promoters in deep phylogenies enable detection of missing data or assembly problems present in higher vertebrates. The functional importance of bidirectional promoters is indicated by selective pressure to maintain the arrangement of genes regulated by the promoter over long evolutionary time spans. Characteristics unique to bidirectional promoters are further elucidated using a technique for unsupervised classification, known as ESPERR. Conclusion Results of these analyses will aid in our understanding of the evolution of bidirectional promoters, including whether the regulation of two genes evolved as a consequence of their proximity or if function dictated their co-regulation.

  7. PROXIMAL: a method for Prediction of Xenobiotic Metabolism.

    Science.gov (United States)

    Yousofshahi, Mona; Manteiga, Sara; Wu, Charmian; Lee, Kyongbum; Hassoun, Soha

    2015-12-22

    Contamination of the environment with bioactive chemicals has emerged as a potential public health risk. These substances that may cause distress or disease in humans can be found in air, water and food supplies. An open question is whether these chemicals transform into potentially more active or toxic derivatives via xenobiotic metabolizing enzymes expressed in the body. We present a new prediction tool, which we call PROXIMAL (Prediction of Xenobiotic Metabolism) for identifying possible transformation products of xenobiotic chemicals in the liver. Using reaction data from DrugBank and KEGG, PROXIMAL builds look-up tables that catalog the sites and types of structural modifications performed by Phase I and Phase II enzymes. Given a compound of interest, PROXIMAL searches for substructures that match the sites cataloged in the look-up tables, applies the corresponding modifications to generate a panel of possible transformation products, and ranks the products based on the activity and abundance of the enzymes involved. PROXIMAL generates transformations that are specific for the chemical of interest by analyzing the chemical's substructures. We evaluate the accuracy of PROXIMAL's predictions through case studies on two environmental chemicals with suspected endocrine disrupting activity, bisphenol A (BPA) and 4-chlorobiphenyl (PCB3). Comparisons with published reports confirm 5 out of 7 and 17 out of 26 of the predicted derivatives for BPA and PCB3, respectively. We also compare biotransformation predictions generated by PROXIMAL with those generated by METEOR and Metaprint2D-react, two other prediction tools. PROXIMAL can predict transformations of chemicals that contain substructures recognizable by human liver enzymes. It also has the ability to rank the predicted metabolites based on the activity and abundance of enzymes involved in xenobiotic transformation.

  8. Promoting industrialisation

    International Nuclear Information System (INIS)

    Hayfield, F.

    1986-04-01

    When the first nuclear power programme is decided upon, automatically the country has to initiate in parallel a programme to modify or add to its current industrial structure and resources. The extent of this new industrialisation depends upon many factors which both, the Government and the Industries have to consider. The Government has a vital role which includes the setting up of the background against which the industrial promotion should take place and in many cases may have also to play an active role all along this programme. Equally, the existing industries have an important role so as to achieve the most efficient participation in the nuclear programme. Invariably the industrial promotional programme will incur a certain degree of transfer of technology, the extent depending on the policies adopted. For this technology transfer to take place efficiently, both the donor and the receiver have to recognise each other's legitimate ambitions and fears. The transfer of technology is a process having a high human content and both donor and receiver have to take this into account. This can be further complicated when there is a difference in culture between them. Technology transfer is carried out within a contractual and organisational framework which will identify the donor (licensor) and the receiver (licensee). This framework may take various forms from a simple cooperative agreement, through a joint-venture organisation right to a standard contract between two separate entities. Each arrangement has its advantages and drawbacks and requires investment of different degrees. One of the keys to a successful industrial promotion is having it carried out in a timely fashion which will be parallel with the nuclear power programme. Experience in some countries has shown the problems when the industrialisation is out of phase with the programme whilst in other cases this industrialisation was at a level and scale unjustified. (author)

  9. Calculus Rules for V-Proximal Subdifferentials in Smooth Banach Spaces

    Directory of Open Access Journals (Sweden)

    Messaoud Bounkhel

    2016-01-01

    Full Text Available In 2010, Bounkhel et al. introduced new proximal concepts (analytic proximal subdifferential, geometric proximal subdifferential, and proximal normal cone in reflexive smooth Banach spaces. They proved, in p-uniformly convex and q-uniformly smooth Banach spaces, the density theorem for the new concepts of proximal subdifferential and various important properties for both proximal subdifferential concepts and the proximal normal cone concept. In this paper, we establish calculus rules (fuzzy sum rule and chain rule for both proximal subdifferentials and we prove the Bishop-Phelps theorem for the proximal normal cone. The limiting concept for both proximal subdifferentials and for the proximal normal cone is defined and studied. We prove that both limiting constructions coincide with the Mordukhovich constructions under some assumptions on the space. Applications to nonconvex minimisation problems and nonconvex variational inequalities are established.

  10. MR imaging of proximal femur: age-related changes

    International Nuclear Information System (INIS)

    Kim, Ju Heon; Jeon, Woo Jin; Sohn, Cheol Ho; Park, Mi Ok; Lee, Seong Mun; Joo, Yang Gu; Suh, Soo Jhi; Pyun, Young Sik

    1995-01-01

    The purpose of this study is to illustrate MR patterns of signal intensity of proximal femur in normal subjects according to the age distribution. T1-weighted MR images of the proximal femur in 125 subjects, aged 13 days to 25 years, were retrospectively analyzed. Age distribution was classified to 4 groups; below 4 months, 5 months to 4 years, 5 years to 14 years, and 15 years to 25 years. By the age of 4 months, the non-ossified femoral epiphysis was seen as intermediate-signal-intensity cartilage. At 5 months-4 years, the ossified femoral capital epiphysis was seen within intermediate-signal-intensity cartilage and appeared as decreased or increased signal-intensity red or yellow marrow surrounded by a rim of low-signal-intensity cortical bone. At 5-14 years, the ossified femoral capital and greater trochanteric epiphysis were seen within the intermediate-signal-intensity cartilage and appeared as decreased or increased signal-intensity red or yellow marrow. At 15-25 years, the proximal metaphyseal marrow showed increased signal intensity. Four patterns of the metaphyseal marrow were recognized by Ricci et al. The frequency of pattern 1 a progressively decreased with age. Pattern 2 and 3 were visible in the 15-25 years age group. An understanding of the spectrum of normal age-related change of the proximal femoral cartilage and marrow patterns serves as the foundation for interpretation of proximal femur pathologies

  11. Topology of digital images visual pattern discovery in proximity spaces

    CERN Document Server

    Peters, James F

    2014-01-01

    This book carries forward recent work on visual patterns and structures in digital images and introduces a near set-based a topology of digital images. Visual patterns arise naturally in digital images viewed as sets of non-abstract points endowed with some form of proximity (nearness) relation. Proximity relations make it possible to construct uniform topolo- gies on the sets of points that constitute a digital image. In keeping with an interest in gaining an understanding of digital images themselves as a rich source of patterns, this book introduces the basics of digital images from a computer vision perspective. In parallel with a computer vision perspective on digital images, this book also introduces the basics of prox- imity spaces. Not only the traditional view of spatial proximity relations but also the more recent descriptive proximity relations are considered. The beauty of the descriptive proximity approach is that it is possible to discover visual set patterns among sets that are non-overlapping ...

  12. Biomechanical evaluation of straight antegrade nailing in proximal humeral fractures: the rationale of the "proximal anchoring point".

    Science.gov (United States)

    Euler, Simon A; Petri, Maximilian; Venderley, Melanie B; Dornan, Grant J; Schmoelz, Werner; Turnbull, Travis Lee; Plecko, Michael; Kralinger, Franz S; Millett, Peter J

    2017-09-01

    Varus failure is one of the most common failure modes following surgical treatment of proximal humeral fractures. Straight antegrade nails (SAN) theoretically provide increased stability by anchoring to the densest zone of the proximal humerus (subchondral zone) with the end of the nail. The aim of this study was to biomechanically investigate the characteristics of this "proximal anchoring point" (PAP). We hypothesized that the PAP would improve stability compared to the same construct without the PAP. Straight antegrade humeral nailing was performed in 20 matched pairs of human cadaveric humeri for a simulated unstable two-part fracture. Biomechanical testing, with stepwise increasing cyclic axial loading (50-N increments each 100 cycles) at an angle of 20° abduction revealed significantly higher median loads to failure for SAN constructs with the PAP (median, 450 N; range, 200-1.000 N) compared to those without the PAP (median, 325 N; range, 100-500 N; p = 0.009). SAN constructs with press-fit proximal extensions (endcaps) showed similar median loads to failure (median, 400 N; range, 200-650 N), when compared to the undersized, commercially available SAN endcaps (median, 450 N; range, 200-600 N; p = 0.240). The PAP provided significantly increased stability in SAN constructs compared to the same setup without this additional proximal anchoring point. Varus-displacing forces to the humeral head were superiorly reduced in this setting. This study provides biomechanical evidence for the "proximal anchoring point's" rationale. Straight antegrade humeral nailing may be beneficial for patients undergoing surgical treatment for unstable proximal humeral fractures to decrease secondary varus displacement and thus potentially reduce revision rates.

  13. Influence of Reduction Promoters on Stability of Cobalt/g-Alumina Fischer-Tropsch Synthesis Catalysts

    OpenAIRE

    Gary Jacobs; Wenping Ma; Burtron H. Davis

    2014-01-01

    This focused review article underscores how metal reduction promoters can impact deactivation phenomena associated with cobalt Fischer-Tropsch synthesis catalysts. Promoters can exacerbate sintering if the additional cobalt metal clusters, formed as a result of the promoting effect, are in close proximity at the nanoscale to other cobalt particles on the surface. Recent efforts have shown that when promoters are used to facilitate the reduction of small crystallites with the aim of increasing...

  14. Promoting employee health by integrating health protection, health promotion, and continuous improvement: a longitudinal quasi-experimental intervention study.

    Science.gov (United States)

    von Thiele Schwarz, Ulrica; Augustsson, Hanna; Hasson, Henna; Stenfors-Hayes, Terese

    2015-02-01

    To test the effects of integrating health protection and health promotion with a continuous improvement system (Kaizen) on proximal employee outcomes (health promotion, integration, and Kaizen) and distal outcomes (workability, productivity, self-rated health and self-rated sickness absence). Twelve units in a county hospital in Sweden were randomized to control or intervention groups using a quasiexperimental study design. All staff (approximately 500) provided self-ratings in questionnaires at baseline, and a 12- and 24-month follow-up (response rate, 79% to 87.5%). There was a significant increase in the proximal outcomes over time in the intervention group compared with the control group, and a trend toward improvement in the distal outcomes workability and productivity. Integration seems to promote staff engagement in health protection and promotion, as well as to improve their understanding of the link between work and health.

  15. Comparison of different proximity potentials for asymmetric colliding nuclei

    International Nuclear Information System (INIS)

    Dutt, Ishwar; Puri, Rajeev K.

    2010-01-01

    Using the different versions of phenomenological proximity potential as well as other parametrizations within the proximity concept, we perform a detailed comparative study of fusion barriers for asymmetric colliding nuclei with asymmetry parameter as high as 0.23. In all, 12 different proximity potentials are robust against the experimental data of 60 reactions. Our detailed study reveals that the surface energy coefficient as well as radius of the colliding nuclei depend significantly on the asymmetry parameter. All models are able to explain the fusion barrier heights within ±10% on the average. The potentials due to Bass 80, AW 95, and Denisov DP explain nicely the fusion cross sections at above- as well as below-barrier energies.

  16. High-throughput determination of RNA structure by proximity ligation.

    Science.gov (United States)

    Ramani, Vijay; Qiu, Ruolan; Shendure, Jay

    2015-09-01

    We present an unbiased method to globally resolve RNA structures through pairwise contact measurements between interacting regions. RNA proximity ligation (RPL) uses proximity ligation of native RNA followed by deep sequencing to yield chimeric reads with ligation junctions in the vicinity of structurally proximate bases. We apply RPL in both baker's yeast (Saccharomyces cerevisiae) and human cells and generate contact probability maps for ribosomal and other abundant RNAs, including yeast snoRNAs, the RNA subunit of the signal recognition particle and the yeast U2 spliceosomal RNA homolog. RPL measurements correlate with established secondary structures for these RNA molecules, including stem-loop structures and long-range pseudoknots. We anticipate that RPL will complement the current repertoire of computational and experimental approaches in enabling the high-throughput determination of secondary and tertiary RNA structures.

  17. Fractures of the proximal humerus involving the intertubercular groove

    International Nuclear Information System (INIS)

    Ahovuo, J.; Paavolainen, P.; Bjoerkenheim, J.M.; Helsinki Univ. Central Hospital

    1989-01-01

    The purpose of this study was to analyse the involvement of the gliding surface of the biceps tendon in fractures of the proximal humerus. Fifteen patients had a fracture of the proximal humerus verified with antero-posterior and axillary radiographs. Tangential radiographs of the intertubercular groove, obtained from the shoulder joint, showed involvement of the intertubercular groove in 13 patients (87%), which could not be shown with other projections. Groove radiographs revealed in 3 patients a dislocation of the fragments of the greater tuberosity large enough to require surgical treatment, but which had not been found using conventional techniques. Therefore, a groove radiograph should be used to precise fractures of the proximal humerus. (orig.)

  18. Modular endoprosthetic replacement for metastatic tumours of the proximal femur

    Directory of Open Access Journals (Sweden)

    Carter Simon R

    2008-11-01

    Full Text Available Abstract Background and aims Endoprosthetic replacements of the proximal femur are commonly required to treat destructive metastases with either impending or actual pathological fractures at this site. Modular prostheses provide an off the shelf availability and can be adapted to most reconstructive situations for proximal femoral replacements. The aim of this study was to assess the clinical and functional outcomes following modular tumour prosthesis reconstruction of the proximal femur in 100 consecutive patients with metastatic tumours and to compare them with the published results of patients with modular and custom made endoprosthetic replacements. Methods 100 consecutive patients who underwent modular tumour prosthetic reconstruction of the proximal femur for metastases using the METS system from 2001 to 2007 were studied. The patient, tumour and treatment factors in relation to overall survival, local control, implant survival and complications were analysed. Functional scores were obtained from surviving patients. Results and conclusion There were 45 male and 55 female patients. The mean age was 60.2 years. The indications were metastases. Seventy five patients presented with pathological fracture or with failed fixation and 25 patients were at a high risk of developing a fracture. The mean follow up was 15.9 months [range 0–77]. Three patients died within 2 weeks following surgery. 69 patients have died and 31 are alive. Of the 69 patients who were dead 68 did not need revision surgery indicating that the implant provided single definitive treatment which outlived the patient. There were three dislocations (2/5 with THR and 1/95 with unipolar femoral heads. 6 patients had deep infections. The estimated five year implant survival (Kaplan-Meier analysis was 83.1% with revision as end point. The mean TESS score was 64% (54%–82%. We conclude that METS modular tumour prosthesis for proximal femur provides versatility; low implant related

  19. An anatomical study of the proximal aspect of the medial femoral condyle to define the proximal-distal condylar length

    Directory of Open Access Journals (Sweden)

    Chia-Ming Chang

    2017-01-01

    Full Text Available Objective: Despite its possible role in knee arthroplasty, the proximal-distal condylar length (PDCL of the femur has never been reported in the literature. We conducted an anatomic study of the proximal aspect of the medial femoral condyle to propose a method for measuring the PDCL. Materials and Methods: Inspection of dried bone specimens was carried out to assure the most proximal condylar margin (MPCM as the eligible starting point to measure the PDCL. Simulation surgery was performed on seven pairs of cadaveric knees to verify the clinical application of measuring the PDCL after locating the MPCM. Interobserver reliability of this procedure was also analyzed. Results: Observation of the bone specimens showed that the MPCM is a concavity formed by the junction of the distal end of the supracondylar ridge and the proximal margin of the medial condyle. This anatomically distinctive structure made the MPCM an unambiguous landmark. The cadaveric simulation surgical dissection demonstrated that the MPCM is easily accessed in a surgical setting, making the measurement of the PDCL plausible. The intraclass correlation coefficient was 0.78, indicating good interobserver reliability for this technique. Conclusion: This study has suggested that the PDCL can be measured based on the MPCM in a surgical setting. PDCL measurement might be useful in joint line position management, selection of femoral component sizes, and other applications related to the proximal-distal dimension of the knee. Further investigation is required.

  20. Morfología femoral proximal en fracturas de cadera

    OpenAIRE

    Calvo de Mora Rebollo, María Jesús; Albareda Albareda, Jorge Cruz; Seral García, Belén; Martín Ruiz, G.; Lasierra Sanromán, José Manuel; Seral Iñigo, Fernando

    2003-01-01

    Es frecuente observar como pacientes que han sufrido una fractura de cadera, si se fracturan posteriormente la cadera contralateral, es del mismo tipo que la primera fractura. El objetivo de este trabajo es tratar de relacional la morfología femoral proximal con la producción de un tipo determinado de fractura. Para ello hemos realizado un estudio prospectivo en 50 pacientes mayores de 65 años, sin distinción de sexo, que han ingresado en nuestro servicio por fractura femoral proximal, 25 ...

  1. True aneurysm of the proximal occipital artery: Case report.

    Science.gov (United States)

    Illuminati, Giulio; Cannistrà, Marco; Pizzardi, Giulia; Pasqua, Rocco; Frezzotti, Francesca; Calio', Francesco G

    2018-01-01

    True aneurysms of the proximal occipital artery are rare, may cause neurological symptoms due to compression of the hypoglossal nerve and their resection may be technically demanding. The case of an aneurysm of the proximal occipital artery causing discomfort and tongue deviation by compression on the hypoglossal nerve is reported. Postoperative course after resection was followed by complete regression of symptoms. Surgical resection, as standard treatment of aneurysms of the occipital artery, with the eventual technical adjunct of intubation by the nose is effective in durably relieving symptoms and preventing aneurysm-related complication. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. True aneurysm of the proximal occipital artery: Case report

    Directory of Open Access Journals (Sweden)

    Giulio Illuminati

    Full Text Available Introduction: True aneurysms of the proximal occipital artery are rare, may cause neurological symptoms due to compression of the hypoglossal nerve and their resection may be technically demanding. Presentation of case: The case of an aneurysm of the proximal occipital artery causing discomfort and tongue deviation by compression on the hypoglossal nerve is reported. Postoperative course after resection was followed by complete regression of symptoms. Conclusion: Surgical resection, as standard treatment of aneurysms of the occipital artery, with the eventual technical adjunct of intubation by the nose is effective in durably relieving symptoms and preventing aneurysm-related complication. Keywords: Arterial aneurysm, Occipital artery, Case report

  3. Bizarre parosteal osteochondromatous proliferation of the proximal humerus: case report

    International Nuclear Information System (INIS)

    Bush, J.B.; Meyer, Mark S.; Reith, John D.

    2007-01-01

    Bizarre parosteal osteochondromatous proliferation (BPOP), or Nora's lesion, is a rare lesion of bone occurring predominantly in the long bones of the hands and feet. It exists as a puzzling clinical entity of uncertain origins and high recurrence rates after surgical resection. To our knowledge, this clinical entity has not been reported in the proximal aspect of the humerus. An interesting report of a lesion occurring in the proximal humerus, which initially was misinterpreted as a parosteal osteosarcoma, is discussed outlining the clinical, radiographic and pathologic features of the BPOP lesion. (orig.)

  4. Inter-proximal enamel reduction in contemporary orthodontics.

    Science.gov (United States)

    Pindoria, J; Fleming, P S; Sharma, P K

    2016-12-16

    Inter-proximal enamel reduction has gained increasing prominence in recent years being advocated to provide space for orthodontic alignment, to refine contact points and to potentially improve long-term stability. An array of techniques and products are available ranging from hand-held abrasive strips to handpiece mounted burs and discs. The indications for inter-proximal enamel reduction and the importance of formal space analysis, together with the various techniques and armamentarium which may be used to perform it safely in both the labial and buccal segments are outlined.

  5. Bizarre parosteal osteochondromatous proliferation of the proximal humerus: case report

    Energy Technology Data Exchange (ETDEWEB)

    Bush, J.B.; Meyer, Mark S. [Ochsner Clinic Foundation, Department of Orthopedics, New Orleans, LA (United States); Reith, John D. [University of Florida College of Medicine, Departments of Pathology, Immunology and Laboratory Medicine and Orthopaedics and Rehabilitation, Gainesville, Florida (United States)

    2007-06-15

    Bizarre parosteal osteochondromatous proliferation (BPOP), or Nora's lesion, is a rare lesion of bone occurring predominantly in the long bones of the hands and feet. It exists as a puzzling clinical entity of uncertain origins and high recurrence rates after surgical resection. To our knowledge, this clinical entity has not been reported in the proximal aspect of the humerus. An interesting report of a lesion occurring in the proximal humerus, which initially was misinterpreted as a parosteal osteosarcoma, is discussed outlining the clinical, radiographic and pathologic features of the BPOP lesion. (orig.)

  6. Identification of avascular necrosis in the dysplastic proximal femoral epiphysis

    International Nuclear Information System (INIS)

    Mandell, G.A.; Harcke, H.T.; MacKenzie, W.G.; Bassett, G.S.; Scott, C.I. Jr.; Wills, J.S.

    1989-01-01

    Bilateral radiographic irregularities and deformities of the proximal femoral epiphyses are features of both multiple epiphyseal dysplasia and bilateral idiopathic avascular necrosis. In the past these entities have been difficult to differentiate. This report documents radiographically the occurrence of avascular necrosis in 10 patients with multiple epiphyseal dysplasia by recognizing the superimposition of sclerosis and subchondral fissuring on pre-existing symmetrically irregular proximal femoral ossification centers. Scintigraphic (photopenia) or magnetic resonance (loss of signal) criteria of avascular necrosis confirm its added presence and help to establish an imaging scheme to identify avascular necrosis superimposed on multiple epiphyseal dysplasia. (orig.)

  7. Identification of avascular necrosis in the dysplastic proximal femoral epiphysis

    Energy Technology Data Exchange (ETDEWEB)

    Mandell, G A; Harcke, H T [Alfred I. duPont Inst., Wilmington, DE (USA). Dept. of Medical Imaging; MacKenzie, W G; Bassett, G S [Alfred I. duPont Inst., Wilmington, DE (USA). Dept. of Orthopaedics; Scott, Jr, C I [Alfred I. duPont Inst., Wilmington, DE (USA). Dept. of Genetics; Wills, J S [Medical Center of Delaware, Newark, DE (USA). Dept. of Radiology

    1989-07-01

    Bilateral radiographic irregularities and deformities of the proximal femoral epiphyses are features of both multiple epiphyseal dysplasia and bilateral idiopathic avascular necrosis. In the past these entities have been difficult to differentiate. This report documents radiographically the occurrence of avascular necrosis in 10 patients with multiple epiphyseal dysplasia by recognizing the superimposition of sclerosis and subchondral fissuring on pre-existing symmetrically irregular proximal femoral ossification centers. Scintigraphic (photopenia) or magnetic resonance (loss of signal) criteria of avascular necrosis confirm its added presence and help to establish an imaging scheme to identify avascular necrosis superimposed on multiple epiphyseal dysplasia. (orig.).

  8. Superconducting proximity effect in mesoscopic superconductor/normal-metal junctions

    CERN Document Server

    Takayanagi, H; Toyoda, E

    1999-01-01

    The superconducting proximity effect is discussed in mesoscopic superconductor/normal-metal junctions. The newly-developed theory shows long-range phase-coherent effect which explaines early experimental results of giant magnetoresistance oscillations in an Andreev interferometer. The theory also shows that the proximity correction to the conductance (PCC) has a reentrant behavior as a function of energy. The reentrant behavior is systematically studied in a gated superconductor-semiconductor junction. A negative PCC is observed in the case of a weak coupling between the normal metal and the external reservoir. Phase coherent ac effect is also observed when rf is irradiated to the junction.

  9. Atgl gene deletion predisposes to proximal tubule damage by impairing the fatty acid metabolism

    International Nuclear Information System (INIS)

    Chen, Wen; Zhang, Qiong; Cheng, Shiwu; Huang, Jie; Diao, Ge; Han, Jian

    2017-01-01

    Fibrosis is the final common pathway of chronic kidney disease (CKD). Normal lipid metabolism is integral to renal physiology, and disturbances of renal lipid metabolism are increasingly being linked with CKD, including the fibrosis. Adipose triglyceride lipase (ATGL) is the rate-limiting enzyme of lipolysis. In the present study, we used Atgl −/− mice to investigate whether ATGL played a role in the regulation of proximal convoluted tubule (PCT) lipid metabolism and renal fibrosis development. ATGL deficiency led to lipid vacuolation of PCT and tubulointerstitial fibrosis, accompanied by massive albuminuria and decreased creatinine clearance rate (Ccr). In vitro experiments indicated that inhibition of ATGL in proximal tubular cell line HK-2 promoted intracellular lipid deposition, reactive oxygen species (ROS) accumulation and cell apoptosis. Both in vitro and in vivo experiments showed that ATGL inhibition decreased the renal peroxisome proliferator-activated receptorα(PPARα) expression, which implied the suppressed lipid metabolism. The antioxidant N-acetylcysteine (NAC) could partially reverse the effect of ROS accumulation and cell apoptosis, but could not restore the PPARαdecrease. These data raise the possibility that ATGL deficiency could impair the renal fatty acid metabolism though inhibiting PPARαexpression, which may lead to lipid deposition and cell apoptosis of PCT, and finally contribute to the renal fibrosis and dysfunction. - Highlights: • Atgl −/− mice develop tubulointerstitial damage and renal dysfunction. • ATGL deficiency results in lipid accumulation and apoptosis of proximal tubular cells. • ROS scavenger alleviates the ATGL-knockdown mediated lipid accumulation and apoptosis. • PPARαdown-regulation is the reason of ROS elevating in ATGL-knockdown HK-2 cells.

  10. Restoration of regenerative ability of x-rayed newt limbs after grafting of proximal or distal skin

    International Nuclear Information System (INIS)

    Clarke, B.J.

    1978-01-01

    Studies were conducted in order to determine the role of skin in restoring regenerative ability of x-rayed newt limbs. Non-x-rayed skin from the hindlimb was grafted in four ways to x-rayed (2680R) forelimbs, stripped of their own skin: proximal hindlimb skin to the proximal forelimb, proximal hindlimb skin to the distal forelimb, distal hindlimb skin to the distal forelimb, and distal hindlimb skin to the proximal forelimb. The forelimbs were immediately amputated at the distal extent of the skin graft. Thirty-two of thirty-five (92%) x-rayed forelimbs that had received hindlimb skin regenerated. Of those that regenerated, 28.1% were hindlimbs as shown by the presence of five digits; 34.4% had four digits or less; 31.2% had an outgrowth, but no morphogenesis of digits and 6.3% had two hands. The level of the regenerate from x-rayed limbs was determined by the stump, not the hindlimb skin graft. Only proximal hindlimb skin grafts were able to promote the formation of single 5 digit regenerates. X-rayed forelimb skin was grafted onto x-rayed (2680R) hindlimbs after the hindlimb muscle and skin was removed. X-rayed hindlimbs that had received grafts of forelimb skin produced 5-digit regenerates in 6 of 11 cases (55%). Only 2 (18%) had four digits. The remaining animals (27%) exhibited bud-like regenerates. It is concluded that skin is capable of restoring regenerative ability of x-rayed limbs and that these limbs are able to participate in the production of the regenerate

  11. Longitudinal effects of contextual and proximal factors on mother-infant interactions among Brazilian adolescent mothers.

    Science.gov (United States)

    Diniz, Eva; DeSousa, Diogo; Koller, Silvia H; Volling, Brenda L

    2016-05-01

    Adolescent mothers often come from vulnerable backgrounds which might impact the quality of both maternal and infant behavior. Despite the negative impact of adolescent motherhood for maternal and infant behavior, social support may decrease the risks and promote maternal behavior toward the infant. The aim of this study was to investigate longitudinally the effects of proximal (maternal behavior) and distal (mother's perceived social support) variables on infant development in a sample of Brazilian adolescent mothers and their infants. Thirty-nine adolescent mothers (Mage=17.26years; SD=1.71) were observed interacting with their infants at 3 and 6 months postpartum and reported on social support. Results revealed that maternal and infant behavior were associated within and across times. Mothers' perceived social support at 3 months had an indirect effect on infant behavior at 6 months, totally mediated by maternal behavior at 6 months. Our findings revealed the mutual influence between maternal and infant behavior, revealing a proximal process. The results also underscored the importance of the passage of time in the interplay between mother-infant interactions and their developmental context. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. On-Demand Targeting: Investigating Biology with Proximity-Directed Chemistry.

    Science.gov (United States)

    Long, Marcus J C; Poganik, Jesse R; Aye, Yimon

    2016-03-23

    Proximity enhancement is a central chemical tenet underpinning an exciting suite of small-molecule toolsets that have allowed us to unravel many biological complexities. The leitmotif of this opus is "tethering"-a strategy in which a multifunctional small molecule serves as a template to bring proteins/biomolecules together. Scaffolding approaches have been powerfully applied to control diverse biological outcomes such as protein-protein association, protein stability, activity, and improve imaging capabilities. A new twist on this strategy has recently appeared, in which the small-molecule probe is engineered to unleash controlled amounts of reactive chemical signals within the microenvironment of a target protein. Modification of a specific target elicits a precisely timed and spatially controlled gain-of-function (or dominant loss-of-function) signaling response. Presented herein is a unique personal outlook conceptualizing the powerful proximity-enhanced chemical biology toolsets into two paradigms: "multifunctional scaffolding" versus "on-demand targeting". By addressing the latest advances and challenges in the established yet constantly evolving multifunctional scaffolding strategies as well as in the emerging on-demand precision targeting (and related) systems, this Perspective is aimed at choosing when it is best to employ each of the two strategies, with an emphasis toward further promoting novel applications and discoveries stemming from these innovative chemical biology platforms.

  13. Distance-dependent duplex DNA destabilization proximal to G-quadruplex/i-motif sequences

    Science.gov (United States)

    König, Sebastian L. B.; Huppert, Julian L.; Sigel, Roland K. O.; Evans, Amanda C.

    2013-01-01

    G-quadruplexes and i-motifs are complementary examples of non-canonical nucleic acid substructure conformations. G-quadruplex thermodynamic stability has been extensively studied for a variety of base sequences, but the degree of duplex destabilization that adjacent quadruplex structure formation can cause has yet to be fully addressed. Stable in vivo formation of these alternative nucleic acid structures is likely to be highly dependent on whether sufficient spacing exists between neighbouring duplex- and quadruplex-/i-motif-forming regions to accommodate quadruplexes or i-motifs without disrupting duplex stability. Prediction of putative G-quadruplex-forming regions is likely to be assisted by further understanding of what distance (number of base pairs) is required for duplexes to remain stable as quadruplexes or i-motifs form. Using oligonucleotide constructs derived from precedented G-quadruplexes and i-motif-forming bcl-2 P1 promoter region, initial biophysical stability studies indicate that the formation of G-quadruplex and i-motif conformations do destabilize proximal duplex regions. The undermining effect that quadruplex formation can have on duplex stability is mitigated with increased distance from the duplex region: a spacing of five base pairs or more is sufficient to maintain duplex stability proximal to predicted quadruplex/i-motif-forming regions. PMID:23771141

  14. Flexible pressure and proximity sensor surfaces manufactured with organic materials

    NARCIS (Netherlands)

    Fattori, M.; Cantatore, E.; Pauer, G.; Agostinelli, T.; Stadlober, B.; Gold, H.

    2017-01-01

    This paper presents the design of two large-Area active matrixes on foil for pressure and proximity sensing applications. Frontend circuits based on organic thin-film transistors on foil are laminated with screen-printed PDVF-TrFE piezo and pyro sensors to create the complete flexible sensing

  15. Depressionary Effect of Proximity of Residential Properties to Waste ...

    African Journals Online (AJOL)

    Past studies have researched these impacts using a variety of hedonic models and Marginal Implicit Pricing, however, this study takes a special focus on the resident's perspective based on the linear proximity to waste disposal sites. 260 questionnaires were distributed to residents within 1km to the site and Estate ...

  16. Proximal onychomycosis due to Malassezia furfur: a case report

    Directory of Open Access Journals (Sweden)

    Zareei M

    2013-03-01

    Full Text Available Background: The etiologic role of Malassezia furfur in onychomycosis, because of its controversial keratinolytic ability, has not been proven. The most reported cases are distal subungual onychomycosis (DSO. In our knowledge no cases of proximal onychomycosis (PO has been reported. For the first time we report proximal onychomycosis. This case report describes the isolation of Malassezia furfur from fingernails. Case presentation: An Iranian 56- year- old women had been referred to mycology lab with hyperkeratosis in proximal regions of right hand nails and clinical diagnosis of onychomycosis without paronychia in May 2012. She used several medicines for her cardiac disease, mental illness, severe stress and blood glucose fluctuation diseases. Scraping and sampling from nail lesions were done, budding yeast cells with broadband connections were observed in 15% KOH wet mounts. Also, other differentiation tests, consist of staining with methylen blue, cultures and biochemical tests were done. In order to rejecting the probable etiologic role of any dermatophytic or non-dermatophytic fungi in this case, samples were collected from other parts of the body by scotch tape and scraping with scalpel blade too, but the results of direct microscopy and culture were negative. Finally, Malassezia furfur was identified as the causative agent of onychomycosis.Conclusion: Despite failure to prove Malassezia furfur keratinolytic ability, it can be the etiologic agent of proximal onychomycosis that shows the aggressive properties of this species. Its clinical importance is the easier transmission to hospitalized patients and other people.

  17. Proximate and Cholesterol Composition of Selected Fast Foods ...

    African Journals Online (AJOL)

    Fast foods consumption has been on the increase in Nigeria raising concerns about the nutritional and health implications. This study was carried out to determine the proximate composition and cholesterol contents of four commonly consumed fast foods (doughnut, chicken pie, roasted chicken, and Jollof rice) sold in ...

  18. Sharpening a Tool for Teaching: The Zone of Proximal Development

    Science.gov (United States)

    Wass, Rob; Golding, Clinton

    2014-01-01

    Vygotsky's Zone of Proximal Development (ZPD) provides an important understanding of learning, but its implications for teachers are often unclear or limited and could be further explored. We use conceptual analysis to sharpen the ZPD as a teaching tool, illustrated with examples from teaching critical thinking in zoology. Our conclusions are…

  19. Scaffolding Critical Thinking in the Zone of Proximal Development

    Science.gov (United States)

    Wass, Rob; Harland, Tony; Mercer, Alison

    2011-01-01

    This paper explores student experiences of learning to think critically. Twenty-six zoology undergraduates took part in the study for three years of their degree at the University of Otago, New Zealand. Vygotsky's developmental model of the Zone of Proximal Development (ZPD) provided a framework as we examined how critical thinking was developed.…

  20. Proximate and mineral elements composition of five locally ...

    African Journals Online (AJOL)

    The proximate composition of the studied fruits were determined by the standard methods of Official Analytical Chemists, while the Mineral Elements (Ca and Mg) were analyzed using Atomic Absorption Spectrophotometry. The levels of Na+ and K+ were determined using Flame photometry and the level of P was ...

  1. Effect of smoking and sun drying on proximate composition of ...

    African Journals Online (AJOL)

    Effect of smoking and sun drying on proximate composition of Diplotaxodon fish species (Ndunduma) from lake Malawi, Malawi. ... African Journal of Food, Agriculture, Nutrition and Development ... The fish were washed then weighed and thereafter, smoked in a traditional smoking kiln and sun dried on reed mats.

  2. Proximal tibiofibular dislocation: a case report and review of literature

    NARCIS (Netherlands)

    Nieuwe Weme, R. A.; Somford, M. P.; Schepers, T.

    2014-01-01

    An isolated dislocation of the proximal tibiofibular joint is uncommon. The mechanism of this injury is usually sports related. We present a case where initial X-rays did not show the tibiofibular joint dislocation conclusively. It was diagnosed after comparative bilateral AP X-rays of the knees

  3. Observing Complex Systems Thinking in the Zone of Proximal Development

    Science.gov (United States)

    Danish, Joshua; Saleh, Asmalina; Andrade, Alejandro; Bryan, Branden

    2017-01-01

    Our paper builds on the construct of the zone of proximal development (ZPD) (Vygotsky in Mind in society: the development of higher psychological processes, Harvard University Press, Cambridge, 1978) to analyze the relationship between students' answers and the help they receive as they construct them. We report on a secondary analysis of…

  4. Comparative physico-chemical and proximate analysis of oils of ...

    African Journals Online (AJOL)

    In rural areas of developing countries like Burkina Faso, nutritive elements are mainly composed of vegetable source. Shea nut, seeds of Sesamum indicum, Cucumis melo and Cucurbita pepo, four species widely consumed were studied. The proximate parameters: moisture, proteins and fat were analysed. Saponification ...

  5. Proximate, phytochemical and mineral compositions of seeds of ...

    African Journals Online (AJOL)

    ALLSWELL

    2012-06-21

    Jun 21, 2012 ... Evaluation of the proximate, phytochemical and mineral compositions of seeds of three tree species was carried out at the University of Agriculture, Umudike. Mature fruits of Allanblackia floribunda,. Garcinia kola and Poga oleosa were collected from the rainforest at Umudike and Oban National Park.

  6. Better access to microcredits: does geographical proximity matter?

    Czech Academy of Sciences Publication Activity Database

    Alimukhamedova, Nargiza

    -, 2013/2014 Winter (2014), s. 24-25 Institutional support: PRVOUK-P23 Keywords : microcredits * geographical proximity Subject RIV: AH - Economics http://www.e-mfp.eu/sites/ default /files/resources/2014/02/e-MFP_Winter2013-2014_Newsletter%20.pdf

  7. Changes in proximate and phytochemical compositions of Persea ...

    African Journals Online (AJOL)

    Persea americana (avocado pear leaves, fruits, and seeds) is one of the medicinal herbs that has been widely utilized in treating/managing disease conditions. In this study, we investigated the changes in proximate and phytochemical compositions of avocado seeds associated with ripening using standard methods.

  8. Proximate, mineral and vitamin C composition of vegetable Gbolo ...

    African Journals Online (AJOL)

    Gbolo (Crassocephalum crepidioides and Crassocephalum rubens) is a traditional leafy vegetable highly consumed in southern and central Benin, as well as in some part of northern Benin. The nutritional potential of the two species of Gbolo were evaluated through their proximate composition, mineral and vitamin C ...

  9. Proximity effect in normal metal-multiband superconductor hybrid structures

    NARCIS (Netherlands)

    Brinkman, Alexander; Golubov, Alexandre Avraamovitch; Kupriyanov, M. Yu

    2004-01-01

    A theory of the proximity effect in normal metal¿multiband superconductor hybrid structures is formulated within the quasiclassical Green's function formalism. The quasiclassical boundary conditions for multiband hybrid structures are derived in the dirty limit. It is shown that the existence of

  10. User's proximity effects for talk mode in mobile phones

    DEFF Research Database (Denmark)

    Pelosi, Mauro; B. Knudsen, Mikael; Pedersen, Gert Frølund

    Thanks to a recent grip study, 3D CAD model of the human hand have been generated, investigating user's proximity effects for talk mode in mobile phones. The simulation results show that the human hand exhibits a major contribution in determining the total loss when compared to the phantom head...

  11. Heavy metal and proximate composition associated with the ...

    African Journals Online (AJOL)

    Changes in the heavy metal content and proximate composition during the 28 day composting of cassava peels used in the cultivation of the oyster mushrooms Pleurotus ostreatus strain EM-1 was studied. Significant dry weight variations of cellulose, hemicellulose and fat contents were observed from day 0 to 12.

  12. Proximate composition and mineral profile of eight different ...

    African Journals Online (AJOL)

    ... eight different sun dried date varieties; (1) Daki, (2) Aseel, (3) Coconut, (4) Khuzravi, (5) Halavi, (6) Zahidi, (7) Deglet Noor and (8) Barkavi were examined to determine their proximate composition and mineral profile. All the date varieties were found to be rich in proteins, fiber, carbohydrates and net gross energy (352.329 ...

  13. Developing survey metrics for analysing cross-border proximity

    DEFF Research Database (Denmark)

    Makkonen, Teemu; Williams, Allan

    2018-01-01

    attempts to operationalize the varying types of proximity – in relation to CBIC – in the form of a questionnaire tested through pilot studies of two CBRs, at the Finnish–Swedish and Danish–German border, and for two contrasting service industries, namely knowledge-intensive business services and tourism...

  14. Proximate analysis of Sweet Potato Toasted Granules | Meludu ...

    African Journals Online (AJOL)

    Sweet potato is an important root crop in the food system of many African countries. The yield, nutrition and economic potential of sweet potato have been identified as very high. In this study, sweet potato was processed and toasted into granules. The proximate analysis performed on the toasted granules showed protein, ...

  15. Correction of Misclassifications Using a Proximity-Based Estimation Method

    Directory of Open Access Journals (Sweden)

    Shmulevich Ilya

    2004-01-01

    Full Text Available An estimation method for correcting misclassifications in signal and image processing is presented. The method is based on the use of context-based (temporal or spatial information in a sliding-window fashion. The classes can be purely nominal, that is, an ordering of the classes is not required. The method employs nonlinear operations based on class proximities defined by a proximity matrix. Two case studies are presented. In the first, the proposed method is applied to one-dimensional signals for processing data that are obtained by a musical key-finding algorithm. In the second, the estimation method is applied to two-dimensional signals for correction of misclassifications in images. In the first case study, the proximity matrix employed by the estimation method follows directly from music perception studies, whereas in the second case study, the optimal proximity matrix is obtained with genetic algorithms as the learning rule in a training-based optimization framework. Simulation results are presented in both case studies and the degree of improvement in classification accuracy that is obtained by the proposed method is assessed statistically using Kappa analysis.

  16. Studies on the proximate composition, functional properties and ...

    African Journals Online (AJOL)

    The present study produced full fat and defatted flours from matured ackee apple arils and evaluated the proximate composition and the effect of pH and salt concentrations on some of the functional properties of the full fat flour and the defatted flour. Matured ackee apple arils were oven-dried at 60 oC and milled to obtain ...

  17. Effect of drought/irrigation on proximate composition and ...

    African Journals Online (AJOL)

    Enset [Ensete ventricosum (Welw.) Cheesman] is an important root crop serving as a carbohydrate rich food source in Ethiopia. Perennial crops, like enset, are often exposed to recurrent dry periods which could greatly affect their growth, physiology and yield. The effect of induced drought/irrigation on the proximate ...

  18. Proximate composition and amino acid profile of rice husk ...

    African Journals Online (AJOL)

    Native rice husk (NRH) was fermented with Pleurotus ostreatus for 7, 14 and 21 days to improve the nutritional values. The proximate composition and amino acid profiles were determined. The results showed that crude fibre (CF), nitrogen free extract (NFE), acid detergent fibre (ADF), and neutral detergent fibre (NDF) were ...

  19. Proximate, phytochemical and mineral compositions of seeds of ...

    African Journals Online (AJOL)

    Evaluation of the proximate, phytochemical and mineral compositions of seeds of three tree species was carried out at the University of Agriculture, Umudike. Mature fruits of Allanblackia floribunda, Garcinia kola and Poga oleosa were collected from the rainforest at Umudike and Oban National Park. The seeds were ...

  20. Microbiological, proximate analysis and sensory evaluation of baked ...

    African Journals Online (AJOL)

    The possibility of making bread of good nutritional, microbiological and sensory qualities from blends of wheat-breadfruit flours was examined. Blends of wheat flour (WF) with percentages of 0, 5, 10, 15, 20 and 25 of breadfruits flour (BF) were used in the production process. The proximate analysis, sensory evaluation and ...

  1. Proximate composition and phytochemistry of seed oil five cultivars ...

    African Journals Online (AJOL)

    Proximate composition and phytochemistry of seed oil five cultivars of Cajanus cajan in Nigeria. BA Iwalokun, OJ Adeyemi, TI Adeleke, EO Abayomi. Abstract. No Abstract. Nigerian Food Journal Vol. 24(1) 2006: 50-60. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  2. Residential proximity to gasoline service stations and preterm birth.

    Science.gov (United States)

    Huppé, Vicky; Kestens, Yan; Auger, Nathalie; Daniel, Mark; Smargiassi, Audrey

    2013-10-01

    Preterm birth (PTB) is a growing public health problem potentially associated with ambient air pollution. Gasoline service stations can emit atmospheric pollutants, including volatile organic compounds potentially implicated in PTB. The objective of this study was to evaluate the relationship between residential proximity to gasoline service stations and PTB. Singleton live births on the Island of Montreal from 1994 to 2006 were obtained (n=267,478). Gasoline service station locations, presence of heavy-traffic roads, and neighborhood socioeconomic status (SES) were determined using a geographic information system. Multivariable logistic regression was used to analyze the association between PTB and residential proximity to gasoline service stations (50, 100, 150, 200, 250, and 500 m), accounting for maternal covariates, neighborhood SES, and heavy-traffic roads. For all distance categories beyond 50 m, presence of service stations was associated with a greater odds of PTB. Associations were robust to adjustment for maternal covariates for distance categories of 150 and 200 m but were nullified when adjusting for neighborhood SES. In analyses accounting for the number of service stations, the likelihood of PTB within 250 m was statistically significant in unadjusted models. Associations were, however, nullified in models accounting for maternal covariates or neighborhood SES. Our results suggest that there is no clear association between residential proximity to gasoline service stations in Montreal and PTB. Given the correlation between proximity of gasoline service stations and SES, it is difficult to delineate the role of these factors in PTB.

  3. Phytochemical, Proximate and Metal Content Analysis of the Leaves ...

    African Journals Online (AJOL)

    Methods: The phytochemical analysis of Psidium guajava was carried out by using a standard procedure. Ash, fat, protein, carbohydrate and fibre contents were determined using proximate analysis while the metal contents were determined using Pearson's method. Results: The phytochemical analysis revealed the ...

  4. Proximate composition and sensory properties of freeze-dried ...

    African Journals Online (AJOL)

    These instant soups and the freshly prepared portions were subjected to proximate and sensory analysis using standard methods. The results of the analysis showed that instant egusi soup contained 10.89 % moisture, 16.93 % ash, 19.73 % crude protein, 15.19 % fat, 13.95 % crude fibre and 23.30 % carbohydrate; while ...

  5. Comparative analysis of the Proximate composition and Sensory ...

    African Journals Online (AJOL)

    Proximate analysis of the samples revealed that the protein, fat, ash, crude fibre and acid insoluble ash contents differed significantly (p<0.05) between samples. With respect to protein and fat contents, dokuwa sample from Doko had the highest values while dokuwa sample from Lapai had the lowest but the reverse was ...

  6. Heavy metal, proximate and microbial profile of some selected ...

    African Journals Online (AJOL)

    The study on the elemental, proximate and microbial composition of fresh samples of Scomber scombrus, Gadus macrocephalus, Saclina pilchradus and Jack mackerel was determined to gain the knowledge of the risk and benefits associated with indiscriminate consumption of marine fishes. Wet digestion was done for the ...

  7. Microbiological and proximate analyses of unripened cheese 'Wara ...

    African Journals Online (AJOL)

    ... may be attributed to poor hygiene of the handlers and manufacturing practices. A careful appraisal of these procedures and the use of pasteurized milk is suggested to reduce the exposure of consumers to health hazard. Key words: Raw milk, Pathogens, Coliforms, Cheese, food borne pathogens, Proximate composition.

  8. Proximate Analysis And The Determination Of Some Physico ...

    African Journals Online (AJOL)

    ... Mg (296.00-371.50 µg/g) and Ca (1165.00-1335.50 µg/g) with few exceptions. The results obtained show good agreement with literature values and provide information on the nutritional value of some of the common evaporated milks sold on Nigerian markets. Keywords: Milk, proximate analysis, physico-chemical, AAS

  9. Performance characteristics of proximity focused ultraviolet image converters

    Science.gov (United States)

    Williams, J. T.; Feibelman, W. A.

    1973-01-01

    Performance characteristics of Bendix type BX 8025-4522 proximity focused image tubes for UV to visible light conversion are presented. Quantum efficiency, resolution, background, geometric distortion, and environmental test results are discussed. The converters use magnesium fluoride input windows with Cs-Te photocathodes and P-11 phosphors on fiber optic output windows.

  10. Proximate and mineral analysis of some wild edible mushrooms

    African Journals Online (AJOL)

    israelikk

    2012-04-12

    Apr 12, 2012 ... Key words: Edible mushroom, mineral composition, proximate analysis. ... than beef, pork and chicken that contain similar nutrients. .... legumes and meat. In earlier studies, Gruen and Wong. (1982) indicated that edible mushrooms were highly nutritional and compared favourably with meat, egg and milk.

  11. Proximate analysis of Lentinus squarrosulus (Mont.) Singer and ...

    African Journals Online (AJOL)

    hope&shola

    Lentinus squarrosulus and Psathyrella atroumbonata, two mushroom species commonly found growing on dead leaves and logs, were collected from the Zaria environ and taken to the laboratory for further studies. Each of the mushroom species was separated into its stipe and pileus and used for proximate analysis.

  12. Radiation tolerant design - theory and practice for proximity sensing

    International Nuclear Information System (INIS)

    Sharp, R.E.; Pater, S.L.; Cook, J.

    1999-01-01

    This paper provides a description of the radiation tolerant design process used to develop a range of proximity detectors with guaranteed total dose lifetime. It also describes some of the applications in which the detectors are being used and the benefits gained by plant operators. (authors)

  13. Leveraging Proximity Sensing to Mine the Behavior of Museum Visitors

    NARCIS (Netherlands)

    Martella, Claudio; Miraglia, Armando; Cattani, Marco; van Steen, Martinus Richardus

    Face-to-face proximity has been successfully leveraged to study the relationships between individuals in various contexts, from a working place, to a conference, a museum, a fair, and a date. We spend time facing the individuals with whom we chat, discuss, work, and play. However, face-to-face

  14. Proximate composition of Mystus bleekeri in relation to body size ...

    African Journals Online (AJOL)

    Proximate composition of small catfish, Mystus bleekeri, from Nala Daik, Sialkot, Pakistan was investigated and fluctuation in relation to body size and condition factor was carried out. Mean percentages for water, fat, protein and ash contents in the whole wet body weight of wild M. bleekeri were 77.87, 3.26, 15.01 and ...

  15. Percutaneous transluminal angioplasty of stenoses of the proximal subclavian artery

    International Nuclear Information System (INIS)

    Grote, R.; Freyschmidt, J.; Walterbusch, G.; Medizinische Hochschule Hannover

    1983-01-01

    Between August 1980 and June 1982, 12 left-sided proximal subclavian stenoses were dilated with balloon catheters. The dilatation was successful in all patients. Differences in blood pressure in the arm could be demonstrated subsequently. Recurrences occurred in two patients after seven and eleven months. Follow-up of nine patients up to 24 months showed them to be symptom-free. (orig.)

  16. Effect of thermal processing methods on the proximate composition ...

    African Journals Online (AJOL)

    The nutritive value of raw and thermal processed castor oil seed (Ricinus communis) was investigated using the following parameters; proximate composition, gross energy, mineral constituents and ricin content. Three thermal processing methods; toasting, boiling and soaking-and-boiling were used in the processing of the ...

  17. Pupils, Tools and the Zone of Proximal Development

    Science.gov (United States)

    Abtahi, Yasmine

    2018-01-01

    In this article, I use the Vygotskian concept of the Zone of Proximal Development (ZPD) to examine the learning experience of two grade seven pupils as they attempted to solve an addition of fractions problem using fraction strips. The aim is to highlight how tools can facilitate the enactment of a ZPD, within which the tool provides the guidance.…

  18. Predicting Performance in Higher Education Using Proximal Predictors

    NARCIS (Netherlands)

    Niessen, A Susan M; Meijer, Rob R; Tendeiro, Jorge N

    2016-01-01

    We studied the validity of two methods for predicting academic performance and student-program fit that were proximal to important study criteria. Applicants to an undergraduate psychology program participated in a selection procedure containing a trial-studying test based on a work sample approach,

  19. Phytochemical, proximate and anti-nutrient compositions of four ...

    African Journals Online (AJOL)

    Chemical constituents of plants are influenced by environmental factors and fluctuations just as many other polygenic traits. Four different green leafy vegetables commonly used in the diets of South Eastern Nigeria were analyzed with a view to determine the phytochemicals, proximate and anti-nutrient compositions of ...

  20. Using an index of habitat patch proximity for landscape design

    Science.gov (United States)

    Eric J. Gustafson; George R. Parker

    1994-01-01

    A proximity index (PX) inspired by island biogeography theory is described which quantifies the spatial context of a habitat patch in relation to its neighbors. The index distinguishes sparse distributions of small habitat patches from clusters of large patches. An evaluation of the relationship between PX and variation in the spatial characteristics of clusters of...

  1. Affordable dual-sensing proximity sensor for touchless interactive systems

    KAUST Repository

    Nassar, Joanna M.; Diaz, Marlon C.; Hussain, Muhammad Mustafa

    2016-01-01

    We report an ultra-low cost flexible proximity sensor using only off-the-shelf recyclable materials such as aluminum foil, napkin and double-sided tape. Unlike previous reports, our device structure exhibits two sensing capabilities in one platform

  2. Innervation of the renal proximal convoluted tubule of the rat

    International Nuclear Information System (INIS)

    Barajas, L.; Powers, K.

    1989-01-01

    Experimental data suggest the proximal tubule as a major site of neurogenic influence on tubular function. The functional and anatomical axial heterogeneity of the proximal tubule prompted this study of the distribution of innervation sites along the early, mid, and late proximal convoluted tubule (PCT) of the rat. Serial section autoradiograms, with tritiated norepinephrine serving as a marker for monoaminergic nerves, were used in this study. Freehand clay models and graphic reconstructions of proximal tubules permitted a rough estimation of the location of the innervation sites along the PCT. In the subcapsular nephrons, the early PCT (first third) was devoid of innervation sites with most of the innervation occurring in the mid (middle third) and in the late (last third) PCT. Innervation sites were found in the early PCT in nephrons located deeper in the cortex. In juxtamedullary nephrons, innervation sites could be observed on the PCT as it left the glomerulus. This gradient of PCT innervation can be explained by the different tubulovascular relationships of nephrons at different levels of the cortex. The absence of innervation sites in the early PCT of subcapsular nephrons suggests that any influence of the renal nerves on the early PCT might be due to an effect of neurotransmitter released from renal nerves reaching the early PCT via the interstitium and/or capillaries

  3. Beyond proximities : The socio-spatial dynamics of knowledge creation

    NARCIS (Netherlands)

    Rutten, R.P.J.H.

    2017-01-01

    Knowledge creation is recognized as interaction between individuals in a social context, but geography-of-knowledge-creation research inadequately connects social context to physical place. The proximities approach reduces physical place to near-far dichotomies and territorial innovation models

  4. The use of pedicled prepucial skin flap urethroplasty for proximal ...

    African Journals Online (AJOL)

    The use of pedicled prepucial skin flap urethroplasty for proximal bulbomembraneous urethral stricture in children: an easy alternative to transpubic urethroplasty. Harshjeet S. Bal, Jujju J. Kurian and Sudipta Sen. Objective Pediatric urethral strictures are not uncommon, and a myriad of treatment options is available.

  5. Worlds largest particle physics laboratory selects Proxim Wireless Mesh

    CERN Multimedia

    2007-01-01

    "Proxim Wireless has announced that the European Organization for Nuclear Research (CERN), the world's largest particle physics laboratory and the birthplace of the World Wide Web, is using it's ORiNOCO AP-4000 mesh access points to extend the range of the laboratory's Wi-Fi network and to provide continuous monitoring of the lab's calorimeters" (1/2 page)

  6. Proximity effects of high voltage electric power transmission lines on ...

    African Journals Online (AJOL)

    The proximity effects of high voltage electric power transmission lines on Leyland Cypress (xCupressocyparis leylandii (Dallim. and A.B. Jacks.) Dallim) and Japanese Privet (Ligustrum japonicum Thunb.) growth were examined in a private nursery located in Sakarya, Turkey. Five transect were randomly chosen in both ...

  7. Effects of fermentation and extrusion on the proximate composition ...

    African Journals Online (AJOL)

    The effect of extrusion and fermentation on the proximate composition and organoleptic properties of six combinations (100:0, 90:10, 80:20, 70:30, 60:40 and 50:50) of sorghum - soya blend were investigated. A total number of 19 microorganisms were isolated during the fermentation of sorghum-soya extrudates; these ...

  8. Phytochemical and proximate analysis of Aspillia kotschyi (Sch ...

    African Journals Online (AJOL)

    The phytochemical and proximate composition of Aspillia Kotschyi belonging to Compositae family which is commonly used as medicinal plant in Nigeria was determined on both the Methanolic and Petroleum spirit extracts of the plant material The Methanolic extract of the plant revealed the presence of carbohydrates, ...

  9. Effect of drying temperatures on the proximate composition and ...

    African Journals Online (AJOL)

    Results of the proximate composition showed that the nutritional qualities of the dried eggs were retained during drying thus the drying temperature did not affect the quality of eggs. The moisture contents of the dried whole egg, dried egg yolk and dried egg white at the different temperatures range from 6.25 -7.23%, ...

  10. Impact of Relational Proximity on Distress from Infidelity

    NARCIS (Netherlands)

    Fisher, Maryanne; Geher, Glenn; Cox, Anthony; Tran, Ulrich S.; Hoben, Ashley; Arrabaca, Andrew; Chaize, Corinna; Dietrich, Robert; Voracek, Martin

    2009-01-01

    Men are generally more distressed by a partner's sexual infidelity whereas women are generally more distressed by a partner's emotional infidelity. The importance of the identity of the interloper, however, has been neglected. We explored the influence of relational proximity (i.e., the degree of

  11. A security review of proximity identification based smart cards

    CSIR Research Space (South Africa)

    Lefophane, S

    2015-03-01

    Full Text Available International Conference on Cyber warfare and Security, Mpumalanga, Kruger National Park, South Africa, 24-25 March 2015 A SECURITY REVIEW OF PROXIMITY IDENTIFICATION BASED SMART CARDS S.Lefophane, J. Van der Merwe Modelling and Digital Science: CSIR...

  12. Effect of Soaking Time on Proximate and Mineral Compositions and ...

    African Journals Online (AJOL)

    Effect of soaking time on some composition of yellow maize was investigated. Yellow maize seeds (Zea mays) were soaked in deionized water for 12, 24, 36 and 48 hours respectively followed by draining, drying and milling. The unsoaked seeds were milled and served as the control. Proximate and mineral compositions ...

  13. The Grammaticalization of the Proximative in Tok Pisin.

    Science.gov (United States)

    Romaine, Suzanne

    1999-01-01

    Discusses grammaticalization of "laik" in Tok Pisin, meaning "want/like/desire" (from English "like") and "klostu," meaning "near" (from English "close to") as markers of proximative. Shows although "klostu" was more generally a feature of Pacific Pidgin English and began to…

  14. Age factor and proximate compositions of the muscle of ...

    African Journals Online (AJOL)

    Significant increases (P < 0.05) in the nitrogen free extract (NFE) of the fish muscle might have been due to the high energy demand imposed on the fish as a positive survival value under the condition of crude oil stress. Keywords: Heterobranchus bidorsalis, Age groups, Proximate composition, Bonny-light crude oil, ...

  15. A STUDY ON PROXIMAL HUMERAL FRACTURES STABILISED WITH PHILOS PLATE

    Directory of Open Access Journals (Sweden)

    Praveen Sivakumar K

    2017-02-01

    Full Text Available BACKGROUND Techniques for treating complex proximal humeral fractures vary and include fixations using tension bands, percutaneous pins, bone suture, T-plates, intramedullary nails, double tubular plates, hemiarthroplasty, plant tan humerus fixator plates, Polaris nails and blade plates. Complications of these techniques include cutout or back out of the screws and plates, avascular necrosis, nonunion, malunion, nail migration, rotator cuff impairment and impingement syndromes. Insufficient anchorage from conventional implants may lead to early loosening and failure, especially in osteoporotic bones. In general, nonoperative treatment of displaced three and four-part fractures of the proximal humerus leads to poor outcome due to intraarticular nature of injury and inherent instability of the fragments. Comminuted fractures of the proximal humerus are at risk of fixation failure, screw loosening and fracture displacement. Open reduction and internal fixation with conventional plate and screws has been associated with unacceptably high incidence of screw pull out. PHILOS (the proximal humeral internal locking system plate is an internal fixation system that enables angled stabilisation with multiple interlocking screws for fractures of the proximal humerus. MATERIALS AND METHODS 30 patients with proximal humerus fractures who were admitted in the Department of Orthopaedics, Government General Hospital, Kakinada, during the period November 2014 - November 2016 were taken up for study according to inclusion criteria. All patients were treated with PHILOS plate. These proximal humerus fractures were classified according to Neer’s classification. Patients were followed up at 6 weeks, 12 weeks and 6 months’ interval. Functional outcomes for pain, range of motion and muscle power and function were assessed using the Constant-Murley scoring system. Collected data analysed with independent t-test and ANNOVA test. RESULTS The outcome of the study was 1

  16. Biomechanical Strength of Retrograde Fixation in Proximal Third Scaphoid Fractures.

    Science.gov (United States)

    Daly, Charles A; Boden, Allison L; Hutton, William C; Gottschalk, Michael B

    2018-04-01

    Current techniques for fixation of proximal pole scaphoid fractures utilize antegrade fixation via a dorsal approach endangering the delicate vascular supply of the dorsal scaphoid. Volar and dorsal approaches demonstrate equivalent clinical outcomes in scaphoid wrist fractures, but no study has evaluated the biomechanical strength for fractures of the proximal pole. This study compares biomechanical strength of antegrade and retrograde fixation for fractures of the proximal pole of the scaphoid. A simulated proximal pole scaphoid fracture was produced in 22 matched cadaveric scaphoids, which were then assigned randomly to either antegrade or retrograde fixation with a cannulated headless compression screw. Cyclic loading and load to failure testing were performed and screw length, number of cycles, and maximum load sustained were recorded. There were no significant differences in average screw length (25.5 mm vs 25.6 mm, P = .934), average number of cyclic loading cycles (3738 vs 3847, P = .552), average load to failure (348 N vs 371 N, P = .357), and number of catastrophic failures observed between the antegrade and retrograde fixation groups (3 in each). Practical equivalence between the 2 groups was calculated and the 2 groups were demonstrated to be practically equivalent (upper threshold P = .010). For this model of proximal pole scaphoid wrist fractures, antegrade and retrograde screw configuration have been proven to be equivalent in terms of biomechanical strength. With further clinical study, we hope surgeons will be able to make their decision for fixation technique based on approaches to bone grafting, concern for tenuous blood supply, and surgeon preference without fear of poor biomechanical properties.

  17. Surgical treatment of proximal humerus fractures using PHILOS plate

    Directory of Open Access Journals (Sweden)

    Vijay Sharma

    2014-10-01

    Full Text Available 【Abstract】Objective: To evaluate functional outcome and complications of open reduction and internal fixation with proximal humeral internal locking system (PHILOS plate for proximal humerus fractures. Methods: We reviewed 51 patients who underwent open reduction and internal fixation with PHILOS plate between the years 2007 to 2012. There were 35 men and 16 women with a mean age of 38 years (range 24-68. There were 41 patients in the age group of <60 years and 10 patients in the age group of >60 years. According to Neer classification system, 8, 15 and 23 patients had 2-part, 3-part, and 4-part fractures, respectively and 5 patients had 4-part fracture dislocation. All surgeries were carried out at our tertiary care trauma centre. Functional evaluation of the shoulder at final follow-up was done using Constant-Murley score. Results: The mean follow-up period was 30 months (range 12-44 months. Two patients were lost to followup. Of the remaining 49 patients, all fractures were united clinically and radiologically. The mean time for radiological union was 12 weeks (range 8-20 weeks. At the final follow-up the mean Constant-Murley score was 79 (range 50-100. The results were excellent in 25 patients, good in 13 patients, fair in 6 atients and poor in 5 patients. During the follow-up, four cases of varus malunion, one case of subacromial impingement, one case of deep infection, one case of intraarticular screw penetration and one case of failure of fi xation were noted. No cases of avascular necrosis, hardware failure, locking screw loosening or nonunion were noted. Conclusion: PHILOS provides stable fixation in proximal humerus fractures. To prevent potential complications like avascular necrosis, meticulous surgical dissection to preserve vascularity of humeral head is necessary. Key words: Proximal humerus fracture; Fracture fixation, internal; Proximal humeral internal locking system

  18. Proximal supination osteotomy of the first metatarsal for hallux valgus.

    Science.gov (United States)

    Yasuda, Toshito; Okuda, Ryuzo; Jotoku, Tsuyoshi; Shima, Hiroaki; Hida, Takashi; Neo, Masashi

    2015-06-01

    Risk factors for hallux valgus recurrence include postoperative round-shaped lateral edge of the first metatarsal head and postoperative incomplete reduction of the sesamoids. To prevent the occurrence of such conditions, we developed a proximal supination osteotomy of the first metatarsal. Our aim was to describe this novel technique and report the outcomes in this report. Sixty-six patients (83 feet) underwent a distal soft tissue procedure combined with a proximal supination osteotomy. After the proximal crescentic osteotomy, the proximal fragment was pushed medially, and the distal fragment was abducted, and then the distal fragment of the first metatarsal was manually supinated. Outcomes were assessed using the American Orthopaedic Foot & Ankle Society (AOFAS) score and radiographic examinations. The average follow-up duration was 34 (range, 25 to 52) months. The mean AOFAS score improved significantly from 58.0 points preoperatively to 93.8 points postoperatively (P hallux valgus and intermetatarsal angle decreased significantly from 38.6 and 18.0 degrees preoperatively to 11.0 and 7.9 degrees postoperatively, respectively (both, P hallux valgus, defined as a hallux valgus angle ≥ 25 degrees. The rates of occurrence of a positive round sign and incomplete reduction of the sesamoids significantly decreased postoperatively, which may have contributed to the low hallux valgus recurrence rates. We conclude that a proximal supination osteotomy was an effective procedure for correction of hallux valgus and can achieve a low rate of hallux valgus recurrence. Level IV, retrospective case series. © The Author(s) 2015.

  19. Distal and proximal predictors of snacking at work: A daily-survey study.

    Science.gov (United States)

    Sonnentag, Sabine; Pundt, Alexander; Venz, Laura

    2017-02-01

    This study aimed at examining predictors of healthy and unhealthy snacking at work. As proximal predictors we looked at food-choice motives (health motive, affect-regulation motive); as distal predictors we included organizational eating climate, emotional eating, and self-control demands at work. We collected daily survey data from 247 employees, over a period of 2 workweeks. Multilevel structural equation modeling showed that organizational eating climate predicted health as food-choice motive, whereas emotional eating and self-control demands predicted affect regulation as food-choice motive. The health motive, in turn, predicted consuming more fruits and more cereal bars and less sweet snacks; the affect-regulation motive predicted consuming more sweet snacks. Findings highlight the importance of a health-promoting eating climate within the organization and point to the potential harm of high self-control demands at work. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  20. Mlh2 is an accessory factor for DNA mismatch repair in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Christopher S Campbell

    2014-05-01

    Full Text Available In Saccharomyces cerevisiae, the essential mismatch repair (MMR endonuclease Mlh1-Pms1 forms foci promoted by Msh2-Msh6 or Msh2-Msh3 in response to mispaired bases. Here we analyzed the Mlh1-Mlh2 complex, whose role in MMR has been unclear. Mlh1-Mlh2 formed foci that often colocalized with and had a longer lifetime than Mlh1-Pms1 foci. Mlh1-Mlh2 foci were similar to Mlh1-Pms1 foci: they required mispair recognition by Msh2-Msh6, increased in response to increased mispairs or downstream defects in MMR, and formed after induction of DNA damage by phleomycin but not double-stranded breaks by I-SceI. Mlh1-Mlh2 could be recruited to mispair-containing DNA in vitro by either Msh2-Msh6 or Msh2-Msh3. Deletion of MLH2 caused a synergistic increase in mutation rate in combination with deletion of MSH6 or reduced expression of Pms1. Phylogenetic analysis demonstrated that the S. cerevisiae Mlh2 protein and the mammalian PMS1 protein are homologs. These results support a hypothesis that Mlh1-Mlh2 is a non-essential accessory factor that acts to enhance the activity of Mlh1-Pms1.