The human oncoprotein and chromatin architectural factor DEK counteracts DNA replication stress.

DNA replication stress is a major source of DNA strand breaks and genomic instability, and a hallmark of precancerous lesions. In these hyperproliferative tissues, activation of the DNA damage response results in apoptosis or senescence preventing or delaying their development to full malignancy. In cells, in which this antitumor barrier is disabled by mutations (for example, in p53), viability and further uncontrolled proliferation depend on factors that help to cope with replication-associated DNA damage. Replication problems preferentially arise in chromatin regions harboring complex DNA structures. DEK is a unique chromatin architectural factor which binds to non-B-form DNA structures, such as cruciform DNA or four-way junctions. It regulates DNA topology and chromatin organization, and is essential for the maintenance of heterochromatin integrity. Since its isolation as part of an oncogenic fusion in a subtype of AML, DEK has been consistently associated with tumor progression and chemoresistance. How DEK promotes cancer, however, is poorly understood. Here we show that DEK facilitates cellular proliferation under conditions of DNA replication stress by promoting replication fork progression. DEK also protects from the transmission of DNA damage to the daughter cell generation. We propose that DEK counteracts replication stress and ensures proliferative advantage by resolving problematic DNA and/or chromatin structures at the replication fork.

Automatic segmentation of polyps in colonoscopic narrow-band imaging data.

Colorectal cancer is the third most common type of cancer worldwide. However, this disease can be prevented by detection and removal of precursor adenomatous polyps during optical colonoscopy (OC). During OC, the endoscopist looks for colon polyps. While hyperplastic polyps are benign lesions, adenomatous polyps are likely to become cancerous. Hence, it is a common practice to remove all identified polyps and send them to subsequent histological analysis. But removal of hyperplastic polyps poses unnecessary risk to patients and incurs unnecessary costs for histological analysis. In this paper, we develop the first part of a novel optical biopsy application based on narrow-band imaging (NBI). A barrier to an automatic system is that polyp classification algorithms require manual segmentations of the polyps, so we automatically segment polyps in colonoscopic NBI data. We propose an algorithm, Shape-UCM, which is an extension of the gPb-OWT-UCM algorithm, a state-of-the-art algorithm for boundary detection and segmentation. Shape-UCM solves the intrinsic scale selection problem of gPb-OWT-UCM by including prior knowledge about the shape of the polyps. Shape-UCM outperforms previous methods with a specificity of 92%, a sensitivity of 71%, and an accuracy of 88% for automatic segmentation of a test set of 87 images.

Family health effects: complements or substitutes.

Genetic endowments play a fundamental role in the production of health. At birth individuals have different capacities to be healthy, largely due to genetic dispositions. Whether or not individuals realize this health depends on their choice of health behaviours. Previous research has linked negative factors beyond the individual's control, which include genetic endowments, to both poor health and poor health behaviours. The health economics literature proposes that behaviours and genetic (or family health) endowments can be either substitutes or complements in the production of health. The goal of this paper is to investigate the behavioural consequences of changes in knowledge about one's genetic endowment. Using two waves of the National Health and Nutrition Examination Survey I Epidemiologic Followup Study, I find that for smokers, smoking intensity substitutes for newly diagnosed smoking-related family cancers, while smoking intensity is complementary to newly diagnosed non-smoking-related family cancers. I find no evidence for the hypothesized relationships with respect to alcohol consumption among drinkers. These results have implications for the growing field of genetic testing and test development. These results also reinforce current practices of ascertaining family health histories in the context of medical history taking.

Activation of PKC-beta(I) in glomerular mesangial cells is associated with specific NF-kappaB subunit translocation.

Changes in expression and activity of protein kinase C (PKC) isoforms and early transcription factors may account for alterations in cell behavior seen in diabetes. We studied the expression of PKC-beta(I) in rat glomerular mesangial cells (MCs) cultured in normal or high glucose and compared it with the temporal and spatial expression of dimeric transcription factor (NF-kappaB) p50 and p65. The results show that in unstimulated cells PKC-beta(I) and NF-kappaB p50 are distributed in the cytosol and, on stimulation, their distribution is perinuclear and they are localized to the membrane. Serum-starved MCs cultured in high-glucose medium exhibit a predominantly cytosolic localization of PKC-beta(I) and both p50 and p65 NF-kappaB. However, phorbol 12-myristate 13-acetate (PMA) stimulation of cells grown in the presence of high glucose resulted in membrane translocation of PKC-beta(I) that was associated with nuclear translocation of NF-kappaB p65, but not NF-kappaB p50. Moreover, the translocation to the nucleus for NF-kappaB p65 was significantly higher in MCs exposed to high glucose compared with those exposed to normal glucose. These observations indicate that the NF-kappaB p65, but not NF-kappaB p50, expression and translocation pattern mirrors that of PKC-beta(I), which may be one important pathway by which signaling is enhanced in the high-glucose state.

Linear versus non-linear recordings of transiently-evoked otoacoustic emissions--methodological considerations.

A non-linear technique is predominantly used for the recording of transiently-evoked otoacoustic emissions (TEOAEs). The aim of this study was to compare linear and non-linear TEOAE recordings. TEOAEs were recorded in 22 normal hearing subjects to clicks from 90 to 30 dB SPL in 10 dB steps with the ILO88 system using both linear and non-linear recording techniques. The non-linear recording technique reduces stimulus artifacts for early latencies, but total elimination could not be proved. Both artifact reduction and significant differences between the two kinds of TEOAE recordings were reduced for longer latencies and lower stimulus intensities. For longer latencies (>10 ms) there was no significant difference between "linear" and "non-linear" TEOAEs. A higher signal-to-noise ratio was found for "linear" TEOAEs, resulting in better identification and a higher test-retest correlation. The linear recording technique, which includes new methods of artifact cancellation in comparison to the mainly utilized non-linear recording technique, should be used especially in hearing screening.

Insulin-transferrin-selenous acid in growth medium alters the expression of PKC isoforms in mesangial cells.

Glomerular mesangial cells (MCs) have been used as an in vitro model for glomerular disease. The culture conditions used for these cells vary and include the use of insulin or insulin-transferrin-selenous acid (ITS) in the growth medium. We studied the effect of ITS in the growth medium containing either normal or high glucose on the expression of protein kinase C (PKC) isoforms in MCs. In the presence of ITS in the medium, MCs expressed lower levels of both PKC isoforms in their cytosol in comparison to MCs grown in medium without ITS. Upon stimulation with PMA, both isoforms were translocated to the particulate (nucleus/cytoskeleton) compartment in MCs grown in presence of ITS. However, in the absence of ITS in the growth medium, both PKC isoforms were primarily translocated to the membrane compartment upon PMA stimulation. These results indicate that insulin in the growth medium may activate MCs resulting in translocation of PKC from the cytosol to other subcellular compartments. This effect is even evident in MCs grown in normal glucose concentration. Our data indicate that the use of ITS in growth medium and eventual interpretation from such experiments involving primary mesangial cells grown in culture needs careful evaluation.

AGEs induce oxidative stress and activate protein kinase C-beta(II) in neonatal mesangial cells.

Increased activation of specific protein kinase C (PKC) isoforms and increased nonenzymatic glycation of intracellular and extracellular proteins [the accumulation of advanced glycation end products (AGEs)] are major mechanistic pathways implicated in the pathogenesis of diabetic complications. Blocking PKC-beta(II) has been shown to decrease albuminuria in animal models of diabetes. To demonstrate a direct relationship between AGEs and the induction and translocation of PKC-beta(II), studies were carried out in rat neonatal mesangial cells, known to express PKC-beta(II) in association with rapid proliferation in post-natal development. Oxidative stress was studied by using the fluorescent probe dichlorfluorescein diacetate. Translocation of PKC-beta(II) was demonstrated by using immunofluorescence and Western blotting of fractionated mesangial cells. Induction of intracellular oxidative stress, increase in intracellular calcium, and cytosol to membrane PKC-beta(II) translocation (with no change in PKC-alpha) were demonstrated after exposure to AGE-rich proteins. These data support the hypothesis that AGEs cause mesangial oxidative stress and alterations in PKC-beta(II), changes that may ultimately contribute to phenotypic abnormalities associated with diabetic nephropathy.

The relationship between external threats and smoking in central Harlem.

OBJECTIVES: This study assessed the relationship between external risks, such as personal and neighborhood danger, and smoking by using a new theoretical framework based on competing mortality risk models. METHODS: Regression analyses of self-reported data from residents of Central Harlem, New York, surveyed from 1992 through 1994 (n = 695, response rate = 72%) were used to assess the relationship between smoking and 2 measures of external health threats: levels of neighborhood danger and lifetime trauma. RESULTS: Support for the framework was mixed. At the 95% confidence level, exposure to lifetime trauma was positively related to current smoking status but was not related to the number of cigarettes smoked, conditional on being a smoker. Living in a "somewhat unsafe neighborhood" was also statistically significantly related to current smoking status. CONCLUSIONS: Although the framework implies that policies directed at improving the physical and social environment might improve health through their indirect effects on behaviors, little supporting evidence was found. Smoking rates may decrease if exposure to violence and neighborhood danger is reduced. This framework needs to be tested on larger and more information-rich data sets.

High glucose induces the activity and expression of Na(+)/H(+) exchange in glomerular mesangial cells.

Changes in activity or expression of transporters may account for alterations in cell behavior in diabetes. We sought to ascertain if mesangial cells (MC) grown in different glucose concentrations exhibit changes in activity and expression of acid-extruding transporters, the Na(+)/H(+) and Na(+)-dependent Cl(-)/HCO(-)(3) exchanger. pH(i) was determined by the use of the fluorescent pH-sensitive dye BCECF. In MCs grown in 5 mM glucose (control), the Na(+)/H(+) exchanger was responsible for 31.8 +/- 5.1% of steady-state pH(i), whereas Na(+)-dependent Cl(-)/HCO(-)(3) contributed 62.9 +/- 4.0% (n = 11). In MCs grown in high glucose for 2 wk, Na(+)/H(+) exchange contribution to acid-extrusion increased as follows: 42.3 +/- 4.6% [n = 8, 10 mM, not significant (NS)], 51.1 +/- 5.1% (n = 8, 20 mM, P < 0.01), and 64.8 +/- 5.5% (n = 7, 30 mM, P < 0.001). The Na(+)-dependent Cl(-)/HCO(-)(3) exchanger contributed less [47.0 +/- 4.6, 38.6 +/- 5.8, and 21.1 +/- 3.8%, for 10, 20, and 30 mM glucose, respectively (n > 7)]. We sought to ascertain if the magnitude of the acute stimulated response to ANG II by the Na(+)/H(+) and Na(+)-dependent Cl(-)/HCO(-)(3) exchanger is changed. Na(+)/H(+) exchanger (1.89-fold increase in 30 vs. 5 mM, P < 0.002), but not Na(+)-dependent Cl(-)/HCO(-)(3) exchange (0. 17-fold, NS), exhibited an enhanced response to ANG II (1 microM). Na(+)/H(+) exchange (NHE1) expression was significantly different (1. 72-fold) after prolonged exposure to high glucose. These results suggest that the Na(+)/H(+) exchanger, but not Na(+)-dependent Cl(-)/HCO(-)(3) exchanger, may play an early role in the response to hyperglycemia in the diabetic state.

Glucose-induced changes in protein kinase C and nitric oxide are prevented by vitamin E.

Changes in activity or expression of protein kinase C (PKC), reactive oxygen products, and nitric oxide (NO) may account for the alteration in cell behavior seen in diabetes. These changes have been proposed to be part of the pathophysiology of erectile dysfunction. We sought to ascertain if corpus cavernosal vascular smooth muscle cells (CCSMC) grown in a high glucose milieu exhibit changes in the activity and expression of PKC isoforms, NO, and reactive oxygen products and to find out if these changes are prevented by alpha-tocopherol. Rat CCSMC were grown in 5, 15, and 30 mM glucose concentrations for 3, 7, and 14 days. PKC isoform expression was assayed with isoform-specific antibodies. In CCSMCs grown in 30 mM glucose for 2-wk, PKC-beta(2)-isoform was upregulated (n = 4; P < 0.01), whereas the expression of alpha-, delta-, epsilon-, and beta(1)-isoforms was unchanged. NO as measured by nitrate-to-nitrite ratio was greatly diminished at 14 days in 30 mM (n = 4; P < 0.002) compared with 5 mM glucose. Reactive oxygen products were upregulated at 14 days when they were assayed by the fluorescent probe dichlorofluorescein diacetate bis(acetoxy-methyl) (DCFH-DA) (n = 5; P < 0.01). When these same cells were exposed to alpha-tocopherol for 14 days, there was a reduction of PKC-beta(2) (57.8%; P < 0.01; n = 4) and a reduction in reactive oxygen product formation (71.1%; P < 0.001; n = 4), along with an increase in nitrate-to-nitrite ratio (43.9%; P < 0.01, n = 4). These results suggest that there may be an interrelationship between PKC, NO, and reactive oxygen product formation in CCSMC exposed to a high glucose environment.

Disease pattern recognition in infrared spectra of human sera with diabetes mellitus as an example.

To benefit from the full information content of the mid-IR spectra of human sera, we directly related the overall shape of the spectra to the donors' disease states. For this approach of disease pattern recognition we applied cluster analysis and discriminant analysis to the example of the disease states diabetes type 1, diabetes type 2, and healthy. In a binary, supervised classification of any pair of these disease states we achieved specificities and sensitivities of approximately 80% within our data set.

Antisense and kidney cell research.

Antisense oligodeoxynucleotides offer the potential to block the expression of specific genes with the goal of altering the phenotypic behavior of the cell. Antisense technology has attracted special interest as potential therapeutic agents for the treatment of genetic disorders, viral infections, and most recently proliferative diseases such as glomerular kidney disease. This technique has recently been used for in vitro and in vivo studies in renal cells. The use of antisense technology has been applied in vitro to help define both the normal mechanisms of specific ion transport and function and the pathobiological processes leading to glomerular proliferation and matrix formation. Most promising are the recent uses of antisense technology in vivo that have been used to treat the damaged peritoneum and alter glomerular remodeling in experimental animal models. It is hoped that widespread use of antisense will not only provide new insight into the normal regulatory behavior of the kidney cells but also allow one to develop therapeutic strategies to treat kidney disease.

Nonlinear mechanics of the inner ear and its relation to otoacoustic emissions: two steps on the way to a mathematical model of DPOAE generation.

Among clinical users of the registration of distortion product otoacoustic emissions (DPOAE), the understanding of the basic causality and interpretation of the phenomenon is not yet widely spread, nor is the expected influence of the middle ear and ear canal clear. On the other side, the effort in mathematical modeling of middle and inner ear structures is driven very far by now. We are convinced, though, that the essentials of an effect as DPOAE generation must be understandable from quite simple models. In a first step de Boer's one-dimensional model was adopted and expanded by a weak frictional and a weak elastic nonlinearity, respectively. By means of perturbation theory the weakly nonlinear problem is converted in an approximation series of linear problems. So it is solvable by the common methods of linear differential equations (DEs), above all the superposition principle can be used. At the same time a structure of causality is introduced: Sources for outgoing waves are in first order approximation formed by incoming waves, and so they can be localized. The calculations show clearly that of all six cubic distortions only the 2f(1) - f(2) term does have a source in its 'allowed' region and so can travel outward. We can use the calculated DPOAE to study the influence of middle ear, external ear canal and probe plug. Some problems remain: the weakly nonlinear model in first order does not give account for proper L(dp) = f(L(1), L(2)) and L(dp) = f(f(2)/f(1)) dependency, nor does it deliver additional sources or the effect of additional suppressor tones. In a second step, therefore, we replace de Boer's simple model basilar membrane (BM) by a doubly resonant, coupled tectorial/basilar membrane (TM/BM) system. By feedback now we introduce a strong nonlinearity, which we can mathematically care for by an iterative feedback loop. The algorithm shapes the incoming waves according to strong compressive nonlinearity. More relastic incoming waves yield better source terms, and after optimization of the mistuning function between TM and BM the model now is able to deliver qualitatively correct L(dp) (L(1),L(2)) and L(dp)(f(2)/f(1)) dependencies.

Risk factors for excess mortality in Harlem. Findings from the Harlem Household Survey.

INTRODUCTION: In 1980, age-adjusted mortality rates in Central Harlem were the highest among New York City's 30 health districts. This population-based study was designed to describe the self-reported frequency of selected health conditions, behavioral risk factors, preventive health practices, and drug use in the Harlem community. METHODS: From 1992 to 1994, in-person interviews were conducted among 695 adults aged 18 to 65 years who were randomly selected from dwelling-unit enumeration lists for the Central Harlem health district. Descriptive statistics were computed for men and women separately, and compared to other population-based surveys. RESULTS: Self-reported medical insurance coverage in Harlem was unexpectedly high (74% of men, 86% of women) as was lifetime use of preventive health practices, e.g., blood cholesterol screening (58% of men, 70% of women). However, lifetime rates of substance use, e.g. crack cocaine (14%) and self-reported history of traumatic events, e.g., witnessing someone seriously injured or violently killed (49% of men, 21% of women) were also high in Harlem, especially in comparison to other populations. CONCLUSIONS: This study has identified important patterns of similarities and differences in risk behaviors between Harlem and other populations. Potential solutions to the health problems of Harlem may lie in the creation of strategies that operate at the community, municipal, and regional level, as well as at the level of individual behavior and risk-taking.

Social epidemiology and the fundamental cause concept: on the structuring of effective cancer screens by socioeconomic status.

Since the early 1800s, studies have consistently demonstrated that people higher in the socioeconomic hierarchy live longer than people of lower rank. One hypothesis for the persistence of this association is that people who are relatively better off are more able to avoid risks by adopting currently available protective strategies. In a partial test of this idea, the social distributions of two cancer screening tests--Pap smears and mammography--were examined. A review of the literature and an analysis of Behavioral Risk Factor Surveillance System (BRFSS) data showed a consistent association between indicators of socioeconomic status and recent screening. These findings support the theory that societies create and shape patterns of disease. Innovations beneficial to health are carried out within the context of inequalities that shape the distribution of the health benefit, thereby affecting patterns of morality.

Region of birth and black diets: the Harlem Household Survey.

OBJECTIVES: This study compared dietary risk factors among Southern-born and other Blacks in Central Harlem. METHODS: A survey of residents of Central Harlem was used to compute a "healthy diet" score for 621 subjects. RESULTS: Southern-born respondents had the highest-risk diets. Although their numbers were small, Caribbean-born respondents, particularly those younger than 45 years, had the lowest-risk diets. CONCLUSIONS: The variation in diets in Central Harlem was considerable, with Southern-born Blacks at highest dietary risk for chronic diseases. These results remain to be tested elsewhere, as does the contribution of other chronic disease risk factors.

Laying down the law: reducing illegal tobacco sales to minors in central Harlem.

OBJECTIVES: This study compared the impact of educational and enforcement interventions on retailers' sale of tobacco to minors in Central Harlem, New York. METHODS: In a randomized trial with repeated measures, 152 stores were randomly divided into control, education, and enforcement groups. RESULTS: Overall tobacco sales to 12- and 13-year-old minors at baseline (98%) were among the highest in the nation. At 6-month and 1-year follow-ups, decreases in rates of tobacco sales to minors were modest among education stores and substantial among enforcement stores. CONCLUSIONS: Effective reduction of tobacco sales to minors may require ongoing enforcement measures, including fines for retailers who violate state and local laws.