Esophageal distensibility measurement: impact on clinical management and procedure length.

Luminal distensibility measurement has demonstrated relevance to various disease processes, though its effects on clinical decision-making have been less well understood. This study aims to characterize the clinical impact of impedance planimetry measurement as well as the learning curve associated with its use in the esophagus. A single provider performed distensibility measurement in conjunction with upper endoscopy for a variety of clinical indications with the functional lumen imaging probe (FLIP) over a period of 21 months. Procedural data were prospectively collected and, along with medical records, retrospectively reviewed. Seventy-three procedures (70 patients) underwent esophageal distensibility measurement over the timeline of this study. The most common procedural indications were known or suspected achalasia (32.9%), dysphagia with connective tissue disease (13.7%), eosinophilic esophagitis (12.3%), and dysphagia with prior fundoplication (9.6%). FLIP results independently led to a change in management in 29 (39.7%) cases and supported a change in management in an additional 15 (20.5%) cases. The most common change in management was a new or amended therapeutic procedure (79.5%). Procedural time added by distensibility measurement was greater among earlier cases than among later cases. The median time added overall was 5 minutes and 46 seconds. Procedural time added varied significantly by procedural indication, but changes in management did not. Distensibility measurement added meaningful diagnostic information that impacted therapeutic decision-making in the majority of cases in which it was performed. Procedural time added by this modality is typically modest and decreases with experience.

Differential expression of hENT1 and hENT2 in colon cancer cell lines.

Human equilibrative nucleoside transporters (hENT) 1 and 2, encoded by SLC29A1 and SLC29A2, permit the bidirectional passage of nucleoside analogues into cells and may correlate with clinical responses to chemotherapy in patients with colorectal cancer (CRC). The purpose of this study was to evaluate the expression profiles of SLC29A1 and SLC29A2 in human cancer cell lines. Using quantitative real-time polymerase chain reaction, we comprehensively profiled the transcription levels of SLC29A1 and SLC29A2 in 16 colon cancer cell lines. We validated the ubiquitous and heterogeneous distribution of SLC29A1 and SLC29A2 in human colon cancer cell lines and demonstrated that SLC29A1 was highly expressed in 25% of metastatic cell lines (Colo201 and Colo205) and 62.5% of primary cell lines (Caco2, Colo320, HCT116, RKO, and SW48). For the first time, we showed that both SLC29A1 and SLC29A2 were expressed at lower levels in colon cancer cell lines originating from metastatic sites than from primary sites. These findings indicate that most patients with metastatic CRC (mCRC) may have low hENT1 expression, and treatment with nucleoside analogues may be inefficient. However, some patients still show high hENT1 expression and have a high probability of benefiting from these drugs. Therefore, evaluating transporter expression profiles and different drug responses between primary and metastatic tumors in patients with mCRC is important. Further assessment of the association between hENTs and drug-based treatment of mCRC is required to elucidate the mechanisms of chemotherapy resistance.

Prognostic value of CpG island methylator phenotype among colorectal cancer patients: a systematic review and meta-analysis.

BACKGROUND: Divergent findings regarding the prognostic value of CpG island methylator phenotype (CIMP) in colorectal cancer (CRC) patients exist in current literature. We aim to review data from published studies in order to examine the association between CIMP and CRC prognosis. MATERIALS AND METHODS: A comprehensive search for studies reporting disease-free survival (DFS), overall survival (OS), or cancer-specific mortality of CRC patients stratified by CIMP is carried out. Study findings are summarized descriptively and quantitatively, using adjusted hazard ratios (HRs) as summary statistics. RESULTS: Thirty-three studies reporting survival in 10 635 patients are included for review. Nineteen studies provide data suitable for meta-analysis. The definition of CIMP regarding gene panel, marker threshold, and laboratory method varies across studies. Pooled analysis shows that CIMP is significantly associated with shorter DFS (pooled HR estimate 1.45; 95% confidence interval (CI) 1.07-1.97, Q = 3.95, I(2) = 0%) and OS (pooled HR estimate 1.43; 95% CI 1.18-1.73, Q = 4.03, I(2) = 0%) among CRC patients irrespective of microsatellite instability (MSI) status. Subgroup analysis of microsatellite stable (MSS) CRC patients also shows significant association between shorter OS (pooled HR estimate 1.37; 95% CI 1.12-1.68, Q = 4.45, I(2) = 33%) and CIMP. Seven studies have explored CIMP's value as a predictive factor on stage II and III CRC patient's DFS after receiving adjuvant 5-fluorouracil (5-FU) therapy: of these, four studies showed that adjuvant chemotherapy conferred a DFS benefit among CIMP(+) patients, one concluded to the contrary, and two found no significant correlation. Insufficient data was present for statistical synthesis of CIMP's predictive value among CRC patients receiving adjuvant 5-FU therapy. CONCLUSION: CIMP is independently associated with significantly worse prognosis in CRC patients. However, CIMP's value as a predictive factor in assessing whether adjuvant 5-FU therapy will confer additional survival benefit to CRC patients remained to be determined through future prospective randomized studies.

HIV Knowledge, Risk Behaviors, and Testing Among Chinese-, Korean-, and Vietnamese-American Women.

The relationship between HIV knowledge and testing behavior is poorly understood among young Chinese-, Korean-, and Vietnamese-American women. This study assesses: (1) levels of HIV/AIDS knowledge, (2) lifetime and annual prevalence of HIV testing, and (3) whether higher levels of HIV knowledge were associated with increased likelihood of testing after controlling for HIV risk behaviors. Fifty-one percent reported lifetime HIV testing (n=117); among those tested, 53% were tested within the past year. A significant and positive association between scores on the HIV Knowledge Questionnaire (HIV KQ-45) and HIV testing was identified. This association was no longer statistically significant after controlling for sexual risk behaviors. Participants were most knowledgeable about HIV symptoms (88.6%) and least knowledgeable about treatment options (56.8%). Future studies should further characterize cultural factors affecting these women's sexual practices, as well develop culturally adapted HIV educational interventions to increase HIV knowledge and testing rates.

Morbidity and mortality in Danio rerio and Pimephales promelas exposed to antilipidemic drug mixtures (fibrates and statins) during embryogenesis: Comprehensive assessment via ante and post mortem endpoints.

Antilipidemic drugs are routinely detected in effluent and surface waters downstream of wastewater treatment plants. A mixture exposure study with nine environmentally relevant antilipidemic drugs was performed with zebrafish (Danio rerio, ZF) and fathead minnow (Pimephales promelas, FHM) embryos to investigate the effects on sensitive embryologic stages. Zebrafish embryos were exposed nominally to: (a) 0.005 µM, (b) 0.05 µM, or (c) 0.5 µM of each drug in the mixture. Fathead minnow embryos were exposed nominally to: (a) 0.0005 µM, (b) 0.005 µM, or (c) 0.05 µM of each drug in the mixture. Several of the individual drug concentrations were within ranges previously found in the environment. Multiple metrics demonstrate that (a) exposure of ZF and FHM embryos to antilipidemic drugs during embryonic development results in lethal and sublethal effects, (b) ZF were more sensitive than FHM based on median lethal concentration (LC50 0.02 µM and 0.05 µM, respectively), but FHM exhibited more severe abnormal sublethal morphologies than zebrafish embryos, and (c) the sublethal effects differed between the two species. This model identified novel specific endpoints for assessing sensitive, sublethal effects of pharmaceuticals in the environment. Abnormal myofiber birefringence pattern, hemorrhage, and heart rate are not included in standard evaluations but each of these metrics demonstrated a dose-dependent response in this study. Results demonstrate risk to fish development with potential repercussions at the population level, especially if environmental concentrations increase.

I have heard about it for the first time from you! Implementation of tobacco control law by police personnel in India.

Setting and Objetives: Police personnel, alongside other key stakeholders, are responsible for implementing the Cigarettes and Other Tobacco Products Act (COTPA) in India. This study aimed to assess knowledge and attitudes about COTPA among police personnel and explore enablers and barriers in implementing it. Design: This convergent parallel mixed-methods study used a self-administered questionnaire (quantitative) and key informant interviews (qualitative). Of 300 police personnel across all eight police stations in Daman, 155 participated. Quantitative data were analysed using descriptive statistics and the χ2 test. Qualitative data from in-depth interviews of six key informants from all coordinating departments were analysed thematically. Results: Overall, 63.2% of responders were aware of any tobacco control law in India, and only 12.9% were trained in its implementation. One person had conducted inspections for COTPA compliance in the last 12 months. The majority (78.1%) of the police personnel, and significantly more tobacco non-users than users (81.2% vs. 52.9%, P = 0.016), felt that enforcing anti-tobacco regulations is one of their most important functions. Perceived benefits of the act and formal authority to act were the two main enablers of COTPA implementation. Lack of awareness and coordination, competing priorities, concentration of authority with higher-ranking officials and evasion of the law by retailers and the public hampered effective implementation of the law. Conclusion: Knowledge about the COTPA was average and implementation poor. Sensitisation and training of implementers, systematic transparent reporting and creating awareness among public are recommended for effective implementation.

Contexte et objectifs : Le personnel de la police, en collaboration avec d'autres partenaires clés, est responsable de la mise en œuvre de la Loi cigarettes et autres produits dérivés du tabac (COTPA) en Inde. Cette étude a eu pour but d'évaluer les connaissances et l'attitude au sein du personnel de la police en ce qui concerne la COTPA et a exploré les facilitateurs et les entraves à sa mise en œuvre.Schéma : Cette étude convergente parallèle à méthodes mixtes s'est basée sur un questionnaire auto-administré (méthode quantitative) et sur des entretiens avec des informateurs clés (méthode qualitative). Sur 300 personnels de police dans les huit stations de police de Daman, 155 ont participé. Les données quantitatives ont été analysées grâce à des statistiques descriptives et au test du χ2. Les données qualitatives émanant des entretiens approfondis avec six informateurs clés de tous les services de coordination ont été analysées de manière thématique.Résultats : Au total, 63,2% des participants étaient au courant de l'existence d'une loi de lutte contre le tabac en Inde, et seulement 12,9% ont été formés à sa mise en œuvre. Un seul avait réalisé des inspections relatives au respect de la COTPA au cours des 12 derniers mois. La majorité (78,1%) du personnel de police, et significativement plus de non-utilisateurs que d' utilisateurs de tabac (81,2% contre 52,9%, P = 0,016), estimaient que mettre en œuvre la loi anti-tabac était l'une de leurs fonctions importantes. Les bénéfices perçus de cette loi et le pouvoir officiel ont été les deux principaux facilitateurs de la mise en œuvre de la COTPA. Le manque de sensibilisation et de coordination, les priorités concurrentes, la concentration de l'autorité au sein des supérieurs et l'évasion de la loi par les revendeurs et le public a entravé une véritable mise en œuvre de la loi.Conclusion : La connaissance de la loi a été moyenne et sa mise en œuvre médiocre. La sensibilisation et la formation des responsables de la mise en œuvre, des rapports systématiques transparents et la sensibilisation du public sont recommandés pour une mise en œuvre efficace.

Marco de Referencia y Objetivos: El personal policial, junto con otros interesados directos, tienen a su cargo la ejecución de la COPTA (del inglés, Cigarettes and Other Tobacco Products Act, por ley sobre el consumo de cigarrillos y otros productos del tabaco) en la India. En el presente estudio se evaluaron los conocimientos y las actitudes de los miembros de la policía con respecto a la COPTA y se exploraron los factores facilitadores y los obstáculos a su aplicación.Método: Fue este un estudio de métodos mixtos convergentes y paralelos que utilizó cuestionarios rellenados por el encuestado (cuantitativos) y entrevistas a informantes clave (cualitativos). De los 300 oficiales de policía de las ocho estaciones de Daman, 155 participaron en la encuesta. Los datos cuantitativos se analizaron mediante métodos estadísticos descriptivos y la prueba del χ2. Los datos cualitativos de las entrevistas exhaustivas de seis informantes clave de todos los departamentos coordinadores se analizaron temáticamente.Resultados: En general, el 63,2% estaba al corriente de una ley de control del tabaco en la India, y solo el 12,9% había recibido capacitación relacionada con su aplicación. Solo un funcionario había realizado inspecciones sobre la conformidad con la COTPA en los últimos 12 meses. La mayor parte del personal de policía (78,1%), y una mayor proporción de no consumidores de tabaco (81,2% contra 52,9%; P = 0,016), consideraba que la aplicación de la reglamentación antitabaco constituía una de sus funciones importantes. Los dos principales factores facilitadores de la aplicación de la COPTA fueron la percepción de los beneficios de la ley y la autoridad oficial para actuar. El desconocimiento y la falta de coordinación, las prioridades concurrentes, la concentración de la autoridad en los funcionarios superiores y la evasión de la ley por parte de los comerciantes al por menor y de la población obstaculizan la aplicación eficaz de la ley.Conclusión: Se observó un conocimiento insuficiente y una escasa aplicación de la COTPA. Con miras a lograr una aplicación eficaz, se recomienda sensibilizar y capacitar al personal encargado de aplicar la ley, practicar una notificación sistemática transparente y trabajar por la concienciación de la población.

The effectiveness of computed tomography-guided biopsy for the diagnosis of spondylodiscitis: an analysis of variables affecting the outcome.

OBJECTIVE: To analyze: (i) the effectiveness of CT-guided biopsy for the diagnosis of suspected spinal infections (spondylodiscitis); (ii) identify common causative microorganisms and assess factors that could affect the diagnostic yield. PATIENTS AND METHODS: Forty-five patients undergoing CT-guided biopsy for suspected spinal infection between November 2012 and October 2014 were analyzed. The time from presentation to diagnosis, administration of antibiotics before biopsy, blood culture results, admission C-reactive protein (CRP)/white cell count, presence of fever or neurological deficits, and soft tissue collections on MRI were analyzed. Multivariable logistic regression was performed to determine variables independently associated with a positive biopsy. RESULTS: Eleven (24.4%) patients had positive blood cultures. The first biopsy was positive in 19 (42.2%) patients. Thirty-eight (84.4%) patients had a single biopsy, while seven (15.5%) patients underwent repeat biopsy with a positive yield in one (14.2%) patient. Overall, causative microorganisms were identified in 26 (57.8%) cases. Admission CRP was significantly associated with isolating the causative pathogen from CT-guided biopsy (p<0.001). A soft tissue collection on MRI was associated with identification of a microorganism in blood cultures (p=0.001). CRP was the only independent variable associated with a positive yield on CT-guided biopsy (p=0.007, OR 1.042) and was more likely in patients with CRP>50 (p<0.001). Administration of empirical antibiotics before biopsy did not affect the yield (p=0.572). CONCLUSIONS: A high CRP was a strong predictor of isolation of the causative organism. Repeat CT-guided biopsy was found to have limited value with a low positive yield (14.2%) in our study.

What is the clinical significance of esophagogastric junction outflow obstruction? evaluation of 60 patients at a tertiary referral center.

BACKGROUND: Esophagogastric junction (EGJ) outflow obstruction (EGJOO) is characterized by impaired EGJ relaxation with intact or weak peristalsis. Our aims were to evaluate: (i) prevalence, (ii) yield of fluoroscopy, endoscopy, and endoscopic ultrasound (EUS), (iii) outcomes, and (iv) whether this data differed based on quantitative EGJ relaxation. METHODS: Studies that met criteria for EGJOO were identified. Demographics, encounters, endoscopy, radiology, treatment decisions, and outcomes were extracted. KEY RESULTS: Sixty studies were identified. Dysphagia was the most common symptom. Forty patients underwent barium esophagram (BE): normal (11), hiatal hernia (20), spasm/dysmotility (17), EGJ narrowing (10), compression (2), Schatzki's ring (5), malrotation (1), gastric volvulus (1), mass (1). Esophagogastroduodenoscopy (EGD) was performed in 41 patients: normal (19), hiatal hernia (13), Schatzki's ring (6), esophagitis (3), esophageal candidiasis (3), mass (1). EUS was performed in 20 patients and was frequently normal. Twenty-two patients underwent intervention. While transient improvement was noted in the majority, persistent improvement was seen in only one of nine patients (dilatation), four of six patients (botulinum toxin), and three patients who underwent per-oral endoscopic myotomy. No patients treated with medical therapy alone had improvement in dysphagia. There was no difference in symptoms or outcomes based on quantitative EGJ relaxation. CONCLUSIONS & INFERENCES: The manometric criterion EGJOO defines a heterogeneous clinical group. While BE, EGD, and EUS all provide complementary information, a significant percentage of these studies will be normal. For patients with dysphagia, outcome may depend on EGJ disruption. There were no differences in symptoms our outcomes based on quantitative EGJ relaxation.

Aging and DNA methylation in colorectal mucosa and cancer.

DNA methylation of promoter-associated CpG islands may function as an alternate mechanism of silencing tumor suppressor genes in multiple neoplasias including colorectal cancer. De novo methylation of genes appears to be an early and frequent event in most neoplasias. For the ER and IGF2 genes, we have previously shown that methylation actually begins in the normal colon mucosa as an age-related event and progresses to hypermethylation in cancer. In this study, we have determined the frequency of age-related methylation in normal colonic mucosa among the genes hypermethylated in colorectal cancer. We studied six genes, including N33, MYOD, p16, HIC-1, THBS1, and CALCA. The N33 gene showed partial methylation in normal colon mucosa, which was age-related (r = 0.7; P = 0.003 using regression analysis). Adenomas and cancers showed further hypermethylation at this locus. Similarly, the MYOD gene showed age-related methylation in normal colon mucosa (r = 0.7; P < 0.00001 using regression analysis) and hypermethylation in cancers. Age-related methylation seems to be gene specific, because p16, THBS1, HIC-1, and CALCA were not affected. Furthermore, this process may also be modulated by tissue-specific factors. Our study suggests that aging is a major contributing factor to hypermethylation in cancer.

Accelerated age-related CpG island methylation in ulcerative colitis.

CpG island hypermethylation is a mechanism of gene silencing that can be usurped by neoplastic cells to inactivate undesirable genes. In the colon, hypermethylation often starts in normal mucosa as a function of age and is markedly increased in cancer. To test the hypothesis that subjects at increased risk of colon cancer have higher levels of methylation in their nonneoplastic mucosa, we studied methylation patterns of five genes in the normal and dysplastic mucosa of patients with ulcerative colitis (UC), a condition associated with a marked increased risk of colon cancer. One gene (Mlh1) was unmethylated in all tissues examined. All four remaining genes had low but detectable levels of methylation in the epithelium of UC patients without evidence of dysplasia, and this methylation was not different from non-UC controls. By contrast, all four genes were highly methylated in dysplastic epithelium from high-grade dysplasia (HGD)/cancer patients with UC; methylation in HGD versus controls averaged 40.0% versus 7.4% (P = 0.00003) for ER, 44.0% versus 3.0% (P < 0.00003) for MYOD, 9.4% versus 2.4% (P = 0.03) for p16 exon 1, and 57.5% versus 30.6% (P = 0.01) for CSPG2. Importantly, three of the four genes were also highly methylated in the normal appearing (nondysplastic) epithelium from these same HGD/cancer patients, indicating that methylation precedes dysplasia and is widespread in these patients. Compared with controls, methylation averaged 20.1% versus 7.2% (P = 0.07) for ER, 18.4% versus 3.0% (P < 0.008) for MYOD, and 7.9% versus 2.4% (P = 0.007) for p16 exon 1. These results are consistent with the hypothesis that age-related methylation marks (and may lead to) the field defect that reflects acquired predisposition to colorectal neoplasia. Furthermore, the data suggest that chronic inflammation is associated with high levels of methylation, perhaps as a result of increased cell turnover, and that UC can be viewed as resulting in premature aging of colorectal epithelial cells.

Association between CpG island methylation and microsatellite instability in colorectal cancer.

De novo methylation of promoter region CpG islands has been increasingly associated with transcriptional inactivation of important genes in neoplasia. To study the potential mechanisms underlying aberrant methylation in cancer, we have determined the methylation patterns of selected genes in colorectal cancers with and without microsatellite instability (MI), which results from defects in one of several base mismatch repair genes. A total of 47 colorectal cancers were analyzed, of which 15 were MI+ (32%). We now report that both the frequency and the extent of de novo methylation are strikingly increased in MI+ cancers. Hypermethylation of the p16 gene was found in 60% of MI+ cancers, compared to only 22% in MI- cancers (P = 0.02). Similarly, hypermethylation of the thrombospondin-1 (TSP-1) gene, an angiogenesis inhibitor, was increased in MI+ cancers (27% versus 0%; P = 0.008). Extensive methylation of insulin-like growth factor II (IGF2) and hypermethylated in cancer-1 (HIC-1) genes was observed in 60 and 80% of MI+ cancers, respectively, as contrasted with 6 and 38% of MI- cancers (P = 0.0002 and 0.01, respectively). Furthermore, 60% of the MI+ cancers displayed the hypermethylation events at two or more loci in a concordant manner compared to only 9% of the MI- cancers (P < 0.001). These results demonstrate a strong link between promoter hypermethylation and genetic instability due to deficient DNA repair.

Identification of differentially methylated sequences in colorectal cancer by methylated CpG island amplification.

CpG island methylation has been linked to tumor suppressor gene inactivation in neoplasia and may serve as a useful marker to clone novel cancer-related genes. We have developed a novel PCR-based method, methylated CpG island amplification (MCA), which is useful for both methylation analysis and cloning differentially methylated genes. Using restriction enzymes that have differential sensitivity to 5-methyl-cytosine, followed by adaptor ligation and PCR amplification, methylated CpG rich sequences can be preferentially amplified. In a model experiment using a probe from exon 1 of the p16 gene, signal was detected from MCA products of a colorectal cancer cell line but not in normal colon mucosa. To identify novel CpG islands differentially methylated in colorectal cancer, we have applied MCA coupled with representational difference analysis to the colon cancer cell line Caco2 as a tester and normal colon mucosa as a driver. Using this strategy, we isolated 33 differentially methylated DNA sequences, including fragments identical to several known genes (PAX6, Versican, alpha-tubulin, CSX, OPT, and rRNA gene). The association of hypermethylation of the clones obtained and transcriptional suppression in colorectal cancer was confirmed by examining the Versican gene, which we found to be silenced in methylated cell lines and reactivated by the methylation inhibitor 5-aza-2'-deoxycytidine. We therefore propose that MCA is a useful technique to study methylation and to isolate CpG islands differentially methylated in cancer.

Aberrant methylation in gastric cancer associated with the CpG island methylator phenotype.

Aberrant methylation of 5' CpG islands is thought to play an important role in the inactivation of tumor suppressor genes in cancer. In colorectal cancer, a group of tumors is characterized by a hypermethylator phenotype termed CpG island methylator phenotype (CIMP), which includes methylation of such genes as p16 and hMLH1. To study whether CIMP is present in gastric cancer, the methylation status of five newly cloned CpG islands was examined in 56 gastric cancers using bisulfite-PCR. Simultaneous methylation of three loci or more was observed in 23 (41%) of 56 cancers, which suggests that these tumors have the hypermethylator phenotype CIMP. There was a significant concordance between CIMP and the methylation of known genes including p16, and hMLH1; methylation of p16 was detected in 16 (70%) of 23 CIMP+ tumors, 1 (8%) of 12 CIMP intermediate tumors, and 1 (5%) of 21 CIMP- tumors (P<0.0001). Methylation of the hMLH1 gene was detected in three of five tumors that showed microsatellite instability, and all three of the cases were CIMP+. The CIMP phenotype is an early event in gastric cancer, being present in the normal tissue adjacent to cancer in 5 of 56 cases. These results suggest that CIMP may be one of the major pathways that contribute to tumorigenesis in gastric cancers.

Methylation and silencing of the Thrombospondin-1 promoter in human cancer.

Neovascularization is a common feature of many human cancers, but relatively few molecular defects have been demonstrated in genes regulating angiogenesis. Decreased expression of Thrombospondin-1 (THBS1), a P53 and Rb regulated angiogenesis inhibitor, has been observed in some human tumors, including glioblastoma multiforme (GBM). To study whether methylation-associated inactivation is involved in down-regulating THBS1 expression in cancer, we analysed the methylation status of THBS1 in several cell lines and primary tumors. Three cell lines (RKO, CEM and RAJI) were completely methylated at several CpG sites within the THBS1 5' CpG island, and had no detectable expression by RT-PCR. THBS1 expression was readily reactivated using the methylation-inhibitor 5-deoxy-azacytidine in all three lines. Furthermore, THBS1 methylation was present in 33% (14/42) of primary GBMs. Thus, de novo methylation may serve as a potential way to inactivate THBS1 expression in human neoplasms.

Concordant methylation of the ER and N33 genes in glioblastoma multiforme.

Methylation of promoter-associated CpG islands appears to be a potential way by which tumor suppressor genes are inactivated in cancer. Using Southern blot analysis, we have studied the methylation of several genes in glioblastoma multiforme (GBM), trying to determine their contribution to tumorigenesis. Genes studied included the estrogen receptor (ER), N33, the candidate tumor-suppressors P15, P16 and HIC1 and a control gene, c-abl. Hypermethylation of N33, ER, HIC1, P16, P15 and c-abl were found in 61%, 59%, 60%, 5%, 2% and 0% of GBM respectively. HIC1 methylation was detected in normal brain as well, but appeared to be more extensive in tumors. ER and N33 methylation were significantly more frequent in tumors from individuals over the age of 40 (70% and 88% vs 36% and 14%). In addition, there was a strong association between ER and N33 methylation, which were concordant in 81% of the cases (P<0.01). ER and N33 methylation in GBM may therefore appear as a result of shared etiologic factors, which may relate in part to aging cell populations in the brain.

Activation of phospholipase C and protein kinase C is required for expression of anthrax lethal toxin cytotoxicity in J774A.1 cells.

Anthrax lethal toxin (LT) comprises two proteins: the protective antigen (PA) and the lethal factor (LF). The LT is cytotoxic to macrophage-like cell line J774A.1. Pre-treatment of these cells with neomycin, a phospholipase C inhibitor, protected them against anthrax LT cytotoxicity. Protection obtained with neomycin indicated that LT stimulates phospholipase C in these cells. It was found that levels of inositol 1,4,5-triphosphate (IP3) dramatically increased in toxin-treated cells. The rise in IP3 levels was proportional to the dose of LF that was allowed to bind to receptor-bound PA. By using protein kinase C (PKC) inhibitors, we found that the activation of PKC is required for mediating anthrax LT cytotoxicity. Activation of phospholipase C or PKC is not required for the binding of PA to the cell surface receptors or for the uptake or internalisation of the toxin. In this study, we demonstrate that the IP3 signalling cascade is initiated by anthrax lethal toxin in J774A.1 cells. The second messengers generated during the cascade aid LF in mediating lethality only after its translocation into the cytosol.

Aging, methylation and cancer.

Alterations in methylation are widespread in cancers. DNA methylation of promoter-associated CpG islands is an alternate mechanism to mutation in silencing gene function, and affects tumor-suppressor genes such as p16 and RBI, growth and differentiation controlling genes such as ER and many others. Evidence is now accumulating that some of these methylation changes may initiate in subpopulations of normal cells as a function of age and progressively increase during carcinogenesis. Age-related methylation appears to be widespread and is one of the earliest changes marking the risk for neoplasia. In colon cancer, we have shown a pattern of age-related methylation for several genes, including ER, IGF2, N33 and MyoD, which progresses to full methylation in adenomas and neoplasms. Hypermethylation of these genes is associated with gene silencing. Age-related methylation involves at least 50% of the genes which are hypermethylated in colon cancer, and we propose that such age-related methylation may partly account for the fact that most cancers occur as a function of old age. Age-related methylation, then, may be a fundamental mark of the field defect in patients with neoplasia. The causes of age-related methylation are still unknown at this point, but evidence points to an interplay between local predisposing factors in DNA (methylation centers), levels of gene expression and environmental exposure. The concept that age-related methylation is a predisposing factor for neoplasia implies that it may serve as a diagnostic risk marker in cancer, and as a novel target for chemoprevention. Studies in animal models support this hypothesis and should lead to novel approaches to risk-assessment and chemoprevention in humans.

Dot pattern processing using voronoi neighborhoods.

A sound notion of the neighborhood of a point is essential for analyzing dot patterns. The past work in this direction has concentrated on identifying pairs of points that are neighbors. Examples of such methods include those based on a fixed radius, k-nearest neighbors, minimal spanning tree, relative neighborhood graph, and the Gabriel graph. This correspondence considers the use of the region enclosed by a point's Voronoi polygon as its neighborhood. It is argued that the Voronoi polygons possess intuitively appealing characteristics, as would be expected from the neighborhood of a point. Geometrical characteristics of the Voronoi neighborhood are used as features in dot pattern processing. Procedures for segmentation, matching, and perceptual border extraction using the Voronoi neighborhood are outlined. Extensions of the Voronoi definition to other domains are discussed.

Mosaic models for textures.

This paper deals with a class of image models based on random geometric processes. Theoretical and empirical results on properties of patterns generated using these models are summarized. These properties can be used as aids in fitting the models to images.

Multiprocessor pyramid architectures for bottom-up image analysis.

This paper describes three hierarchical organizations of small processors for bottom-up image analysis:pyramids, interleaved pyramids, and pyramid trees. Progressively lower levels in the hierarchies process image windows of decreasing size. Bottom-up analysis is made feasible by transmitting up the levels quadrant borders and border-related information that captures quadrant interaction of interest for a given computation. The operation of the pyramid is illustrated by examples of standard algorithms for interior-based computations (e.g., area) and border-based computations of local properties (e.g., perimeter). A connected component counting algorithm is outlined that illustrates the role of border-related information in representing quadrant interaction. Interleaved pyramids are obtained by sharing processors among several pyramids. They increase processor utilization and throughput rate at the cost of increased hardware. Trees of shallow interleaved pyramids, calld pyramid trees, are introduced to reduce the hardware requirements of large interleaved pyramids at the expense of increased processing time, without sacrificing processor utilization. The three organizations are compared with respect to several performance measures.