378 research outputs found

    N-Methyl-N'-nitro-N-nitrosoguanidine-induced senescence-like growth arrest in colon cancer cells is associated with loss of adenomatous polyposis coli protein, microtubule organization, and telomeric DNA

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    BACKGROUND: Cellular senescence is a state in which mammalian cells enter into an irreversible growth arrest and altered biological functions. The senescence response in mammalian cells can be elicited by DNA-damaging agents. In the present study we report that the DNA-damaging agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) is able to induce senescence in the HCT-116 colon cancer cell line. RESULTS: Cells treated with lower concentrations of MNNG (0–25 microM) for 50 h showed a dose-dependent increase in G(2)/M phase arrest and apoptosis; however, cells treated with higher concentrations of MNNG (50–100 microM) showed a senescence-like G(0)/G(1 )phase arrest which was confirmed by increased expression of β-galactosidase, a senescence induced marker. The G(2/)M phase arrest and apoptosis were found to be associated with increased levels of p53 protein, but the senescence-like G(0)/G(1 )phase arrest was dissociated with p53 protein levels, since the p53 protein levels decreased in senescence-like arrested cells. We further, determined whether the decreased level of p53 was a transcriptional or a translational phenomenon. The results revealed that the decreased level of p53 protein in senescence-like arrested cells was a transcriptional phenomenon since p53 mRNA levels simultaneously decreased after treatment with higher concentrations of MNNG. We also examined the effect of MNNG treatment on other cell cycle-related proteins such as p21, p27, cyclin B1, Cdc2, c-Myc and max. The expression levels of these proteins were increased in cells treated with lower concentrations of MNNG, which supported the G(2)/M phase arrest. However, cells treated with higher concentrations of MNNG showed decreased levels of these proteins, and hence, may not play a role in cell cycle arrest. We then examined a possible association of the expression of APC protein and telomeric DNA signals with cellular senescence in MNNG-treated cells. We found that protein and mRNA levels of APC were drastically reduced in cells treated with higher concentrations of MNNG. The loss of APC expression might lead to chromosomal instability as well as microtubular disorganization through its dissociation with tubulin. In fact, the protein level of α-tubulin was also drastically decreased in senescence-like arrested cells treated with higher concentrations of MNNG. The levels of telomeric DNA also decreased in cells treated with higher concentrations of MNNG. CONCLUSIONS: These results suggest that in response to DNA alkylation damage the senescence-like arrest of HCT-116 cells was associated with decreased levels of APC protein, microtubular organization, and telomeric DNA

    A rare pediatric renal tumor: classic congenital mesoblastic nephroma: two cases and review of literature

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    Background Mesoblastic nephroma (Boland’s tumor) is the most common benign renal tumor occurring in infants and neonates. The most common presentation is abdominal mass, but it can have varied presentations because of associated paraneoplastic syndromes. Majority of these tumors can be cured with surgical excision alone; however, long-term follow-up is required for recurrence or metastasis. Histopathologically, it is divided into two subtypes: classic and cellular. The less common cellular congenital mesoblastic nephromas have cellular elements in them and tend to have a more malignant potential.Patients and methods Two patients were studied over a period of 2 years from June 2010 to June 2012.Results By reporting two patients presenting in the infantile period with classic congenital mesoblastic nephromas, an attempt is made in this paper to characterize the clinical behavior of this variety of renal tumors. Hypertension and paraneoplastic syndromes can be associated with this tumor. Herein we compare our experience with other similar cases reported in the literature.Conclusion When renal tumors occur in infancy or at neonatal age, mesoblastic nephroma should be kept in mind. Association of hypertension and paraneoplastic syndromes should be looked for. Surgery is usually curative and postoperative follow-up for recurrence is required, more so in cellular variety

    Hepaticoduodenostomy as a technique for biliary anastomosis in children with choledochal cyst: An experience with 31 cases

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    Objective The aim of this study was to investigate the efficacy and complications of hepaticoduodenostomy in the treatment of choledochal cyst in children. Summary background data The conventional treatment of choledochal cyst includes Roux-en-Y hepaticojejunostomy for biliary reconstruction. This procedure, however, disrupts normal bowel continuity and requires two anastomoses. We studied the technique of hepaticoduodenostomy as an effective alternative to this technique.Patients and methods A total of 31 children undergoing  hepatoduodenostomy for choledochal cyst over a period of 9 years were included in this study.Results The patients operated upon had outcomes similar to those treated by the Roux-en-Y technique in other studies.Conclusion Hepaticoduodenostomy is an effective alternative to the conventional Roux-en-Y anastomotic technique in cases of choledochal cyst in children. Keywords: choledochal cyst, hepaticoduodenostomy, pediatri

    Increasing Efforts to Reduce Cervical Cancer through State-Level Comprehensive Cancer Control Planning

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    Reducing cervical cancer disparities in the U.S. requires intentional focus on structural barriers such as systems and policy which impact access to human papillomavirus (HPV) vaccination, cervical cancer screening and treatment. Such changes are difficult and often politicized. State comprehensive cancer control (CCC) plans are vehicles that, if designed well, can help build collective focus on structural changes. Study objectives were to identify the prioritization of cervical cancer in state CCC plans, the conceptualization of HPV within these plans, and the focus of plans on structural changes to reduce cervical cancer disparities. Data were gathered by systematic content analysis of CCC plans from 50 states and the District of Columbia from February-June 2014 for evidence of cervical cancer prioritization, conceptualization of HPV, and focus on structural barriers to cervical cancer vaccination, screening or treatment. Findings indicate that prioritization of cervical cancer within state CCC plans may not be a strong indicator of state efforts to reduce screening and treatment disparities. While a majority of plans reflected scientific evidence that HPV causes cervical and other cancers, they did not focus on structural elements impacting access to evidence-based interventions. Opportunities exist to improve state CCC plans by increasing their focus on structural interventions that impact cervical cancer prevention, detection, and treatmentparticularly for the 41% of plans ending in 2015 and the 31% ending between 2016-2020. Future studies should focus on the use of policy tools in state CCC plans and their application to cervical cancer prevention and treatment

    The maize brown midrib6 (bm6) mutation encodes a functional GTP Cyclohydrolase1

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    Brown midrib mutations in maize (Zea mays L.) and sorghum (Sorghum bicolor L.) alter lignin composition and enhance cell wall digestibility. These mutations are prime candidates for silage breeding. Six brown midrib mutants are currently known, brown midrib1 (bm1) to brown midrib6 (bm6). The bm1 and bm3 mutations are being used commercially for silage. The underlying genes responsible for five of the six bm mutations in maize (bm1, bm2, bm3, bm4, and bm5) are known. Chen and co-workers (2012) characterized the bm6 mutation, demonstratingthat bm6 increases cell wall digestibility and physically mapped bm6 within a 180 kilobase region on chromosome 2. The present investigation utilized map-based cloning to identify the candidate gene responsible for the bm6 phenotype as GTP Cyclohydrolase1 (GCH1) and validated the candidate gene through reverse genetics. Orthologs of bm6 include at least one paralogous gene in maize on chromosome 10 and various homologs in other grasses and dicots. The discovery that GCH1 is  responsible for the maize bm6 phenotype suggests that GCH1 plays a role in the tetrahydrofolate biosynthetic process

    Festivals and deterioration of aquatic environment: A case study of Idol immersion in Tapi River, India

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    In the civil society different festivals are celebrated, these are the integral part of human life and many of festivals are religious, seasonal change and culturally important. The present study elucidated environmental impact of Ganesh idol immersion on water quality of Tapi River and for this purpose water samples were collected during different durations (pre immersion, during immersion and post immersion) from selected sampling stations or idol immersion points of Tapi River. The important water quality parameters like pH, temperature, dissolved oxygen, free carbon dioxide, total hardness, total alkalinity, biological oxygen demand, chemical oxygen demand, oil & grease and total calcium were analysed for the study. Result shows that dissolved oxygen was depleted while remaining parameter were increased during the idol immersion and it was concluded that aquatic ecosystem of Tapi river was deteriorated and pollution and nutrient load were increased due to these religious activities. The celebration of festivals and these religious activities can’t stop but pollution can reduce to save the river

    Recurrent patterns of DNA copy number alterations in tumors reflect metabolic selection pressures.

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    Copy number alteration (CNA) profiling of human tumors has revealed recurrent patterns of DNA amplifications and deletions across diverse cancer types. These patterns are suggestive of conserved selection pressures during tumor evolution but cannot be fully explained by known oncogenes and tumor suppressor genes. Using a pan-cancer analysis of CNA data from patient tumors and experimental systems, here we show that principal component analysis-defined CNA signatures are predictive of glycolytic phenotypes, including 18F-fluorodeoxy-glucose (FDG) avidity of patient tumors, and increased proliferation. The primary CNA signature is enriched for p53 mutations and is associated with glycolysis through coordinate amplification of glycolytic genes and other cancer-linked metabolic enzymes. A pan-cancer and cross-species comparison of CNAs highlighted 26 consistently altered DNA regions, containing 11 enzymes in the glycolysis pathway in addition to known cancer-driving genes. Furthermore, exogenous expression of hexokinase and enolase enzymes in an experimental immortalization system altered the subsequent copy number status of the corresponding endogenous loci, supporting the hypothesis that these metabolic genes act as drivers within the conserved CNA amplification regions. Taken together, these results demonstrate that metabolic stress acts as a selective pressure underlying the recurrent CNAs observed in human tumors, and further cast genomic instability as an enabling event in tumorigenesis and metabolic evolution

    Single-Mode Squeezed Light Generation and Tomography with an Integrated Optical Parametric Oscillator

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    Quantum optical technologies promise advances in sensing, computing, and communication. A key resource is squeezed light, where quantum noise is redistributed between optical quadratures. We introduce a monolithic, chip-scale platform that exploits the χ(2)\chi^{(2)} nonlinearity of a thin-film lithium niobate (TFLN) resonator device to efficiently generate squeezed states of light. Our system integrates all essential components -- except for the laser and two detectors -- on a single chip with an area of one square centimeter, significantly reducing the size, operational complexity, and power consumption associated with conventional setups. Our work addresses challenges that have limited previous integrated nonlinear photonic implementations that rely on either χ(3)\chi^{(3)} nonlinear resonators or on integrated waveguide χ(2)\chi^{(2)} parametric amplifiers. Using the balanced homodyne measurement subsystem that we implemented on the same chip, we measure a squeezing of 0.55 dB and an anti-squeezing of 1.55 dB. We use 20 mW of input power to generate the parametric oscillator pump field by employing second harmonic generation on the same chip. Our work represents a substantial step toward compact and efficient quantum optical systems posed to leverage the rapid advances in integrated nonlinear and quantum photonics.Comment: 21 pages; 4 figures in main body, 8 supplementary figure
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