Exploring the effect of a lifestyle intervention on cancer risk: 43-year follow-up of the randomized Oslo diet and antismoking study.

BACKGROUND/OBJECTIVES: The Oslo diet and antismoking study showed that counselling for a healthy lifestyle reduced lifelong coronary mortality in high-risk men. We explored whether the same counselling reduced also cancer risk. METHODS: The study randomly allocated males at high coronary risk to either a 5-year intervention for lifestyle changes (cholesterol-lowering dietary changes, weight loss and stopping smoking) or a control group (1 : 1) in 1972/73. We explored the incidence and mortality of all cancers and cancer forms related to smoking, BMI or diet up to 43 years after randomization. RESULTS: A total of 595 men in the intervention and 621 in the control group were included. At inclusion median age was 45 years, 588 (48.4%) subjects were overweight (BMI > 25 kg m-2 ) and 925 (76.1%) current smokers. The intervention did not reduce the risk of cancer after 43 years (adjusted hazard ratio (HR) 0.96, 95% confidence interval (CI) 0.80-1.15). In the first 25 years of follow-up, among the 1088 (89.5%) men who were overweight/obese and/or smokers, the intervention reduced the incidence of those cancer forms related to smoking, BMI or diet (including carcinoma of the respiratory, digestive and urinary tracts; adjusted HR 0.69; 95% CI 0.49-0.99). The intervention had no significant effect on incidence beyond 25 years, or on mortality. CONCLUSIONS: The 5-year counselling for a healthy lifestyle did not reduce the overall cancer risk in the very long term. However, in the first 25 years, the counselling reduced the risk of relevant cancer types in overweight/obese subjects and smokers.

Increasing clinical relevance in oral radiology: Benefits and challenges when implementing digital assessment.

AIMS: The aims of the study were to investigate benefits and challenges in implementing a digital examination and study the clinical relevance of the digital examination in relation to clinical training and practice. MATERIAL AND METHOD: The study was based on semi-structured focus-group interviews from two distinct student populations (2016 and 2017) in a bachelor programme in dental hygiene. In addition, conversational data from a plenary discussion from the whole second student population (2017) were collected and analysed. The data were approached on basis of content analysis. RESULTS: A benefit experienced in the digital examination was the ease in typing and editing answers on the computer. This suggests an increased effectiveness in computer-based compared to analogue examinations. An additional advantage was the experienced relevance of the examination related to the clinic. This finding refers not only to the digital presentations of images, but also to the entire setting in the clinic and dental practice. The limitations reported by the students were non-optimal viewing conditions for presenting radiographic images and difficulties in obtaining an overview of the assignments compared to paper-based examinations due to the linear digital examination format. The last finding on lacking overview revealed an influence on student performances which should be taken seriously in designing digital examinations. CONCLUSION: In conclusion, the digital layout increases efficiency and clinical relevance of examinations to a certain extent. Obstacles were found in limitations related to image presentation and lack of overview of the examination. The latter challenge raises questions related to developing suitable assessment software.

Clinical characteristics of patients with suspected cardiac chest pain and angiographically normal coronary arteries in a secondary care hospital.

BACKGROUND: An important number of patients with suspected cardiac chest pain have non-obstructive coronary artery disease. Our purpose was to describe the clinical characteristics of patients with normal or near-normal coronary arteries in routine cardiological practice in a secondary care hospital. METHODS: In 2013, consecutive patients referred for invasive coronary angiography with suspected cardiac chest pain were analysed at a single-centre (Westfriesgasthuis, Hoorn, the Netherlands). Coronary arteries were defined as normal or near-normal if they showed no stenosis or only slight wall irregularities on visual assessment. Patients with a final non-cardiac diagnosis for the chest pain were excluded. RESULTS: A total of 558 patients were included. Of these, 151 (27%) showed normal or near-normal coronary arteries on visual assessment. This group of patients were significantly more often female (p < 0.001), younger (p < 0.001) and non-diabetic (p = 0.002). Forty percent of hospitalised patients who had normal or near-normal coronary arteries at coronary angiography showed an elevated troponin. CONCLUSION: In routine cardiological practice, around 1 out of 4 patients with suspected cardiac chest pain undergoing invasive angiography had normal or near-normal coronary arteries. We suggest that premenopausal women with suspected cardiac chest pain could be considered for non-invasive coronary imaging as a first step in clinical practice.

Withdrawal time as a quality indicator for colonoscopy - a nationwide analysis.

BACKGROUND AND STUDY AIMS: A withdrawal time of at least 6 min has been recommended as a quality indicator for colonoscopy. One drawback of many of the studies that have investigated withdrawal time and produced conflicting results has been their single-center design involving few endoscopists. Therefore, the validity of withdrawal time as a quality measure remains unclear. This study explores the value of individual withdrawal time in a nationwide analysis. PATIENTS AND METHODS: This prospective cohort study comprised data from outpatient colonoscopies performed at 19 Norwegian centers from January to September 2009 and registered in the Norwegian Gastronet Quality Assurance (QA) program. The participating endoscopists were characterized by their median withdrawal time for visual colonoscopies (diagnostic colonoscopies without biopsy or therapy) and categorized into two visual withdrawal time (VWT) groups (< 6 min or ≥ 6 min) to analyze the predictive value of VWT for detection of one or more polyps ≥ 5 mm in diameter using multiple logistic regression models. RESULTS: The study included 4429 consecutive colonoscopies performed by 67 endoscopists. The adjusted odds ratio for the detection of polyps ≥ 5 mm was 1.21 (95 %CI 0.94 - 1.56, P = 0.14) for endoscopists with a median VWT ≥ 6 min compared with endoscopists with a median VWT < 6 min. CONCLUSION: Withdrawal time using 6 min as the threshold is not a strong predictor of the likelihood of finding a polyp during colonoscopy and should not be used as a quality indicator.

Incontinence after colonoscopy--an unrecognized and preventable problem. A cross-sectional study from the Gastronet quality assurance program.

BACKGROUND: Colonoscopy requires insufflation of gas for visualization of the bowel wall. Worldwide, this is usually done using air. The aim of the present study was to assess the risk of postcolonoscopy incontinence, and to investigate whether insufflation of CO2 instead of air may reduce this risk, since it is easily absorbed through the bowel mucosa. METHODS: This is a prospective multicenter study of colonoscopy patients undergoing bowel insufflation using air or CO2. A successive series of colonoscopies were reported to a national quality assurance program in Norway between January and December 2009 from 21 endoscopy centers with varying insufflation practices. The study comprised 7812 patients aged 18 years or older who were referred for outpatient colonoscopy. Of these, 5015 underwent colonoscopy performed using air and 2797 colonoscopy using CO2 insufflation. RESULTS: Patient-reported incontinence up to 24 h after colonoscopy was compared using binary logistic regression analysis for the type of gas used for insufflation. The air and CO2 patient groups were comparable with regard to age, sex, indication for colonoscopy, and sedation practice. Incontinence was reported by 336 out of 7812 patients (4.3%). Incontinence was significantly less frequent in the CO2 group than in the air group [2.1% versus 5.5%; adjusted odds ratio (OR) 0.38; 95%CI 0.28-0.50; P < 0.001]. Female patients had a higher risk of incontinence than men (adjusted OR 1.77; 95% CI 1.39-2.24; P < 0.001). CONCLUSION: About every 20th patient undergoing colonoscopy using standard air insufflation experiences postexamination incontinence. This proportion can be reduced by 60% by converting from air insufflation to insufflation with the absorbable CO2.

How shelterin solves the telomere end-protection problem.

The symphony of the human genome concludes with a long Gregorian chant of TTAGGG repeats. This monotonous coda represents one of the most complex problems in chromosome biology: the question of how cells distinguish their natural chromosome ends from double-strand breaks elsewhere in the genome. McClintock's classic finding of chromosome breakage-fusion-bridge cycles, first reported by her at one of the early Cold Spring Harbor Laboratory Symposia (the ninth), served as a prelude to this question. The 75th Cold Spring Harbor Laboratory Symposium marks the completion of a series of mouse gene deletion experiments that revealed DNA-damage-response pathways that threaten chromosome ends and how the components of the telomeric shelterin complex prevent activation of these pathways.

A case of cocaine-induced panhypopituitarism with human neutrophil elastase-specific anti-neutrophil cytoplasmic antibodies.

OBJECTIVE: To describe a patient with cocaine-induced panhypopituitarism associated with human neutrophil elastase-anti-neutrophil cytoplasmic antibodies (HNE-ANCA). CASE: A 41-year-old man presented with extreme fatigue, cold intolerance and anorexia with 20 kg weight loss in the last 6 months. His medical history was unremarkable. He snorted cocaine twice a week during the last 6 years. On examination, we saw a pale and skinny man, with a normal blood pressure. Because of the severity of symptoms central hypothyroidism was suspected and very low values of TSH, free thyroxine and free triiodothyronine were measured. His FSH, LH, ACTH, cortisol, prolactin and testosterone levels were also low. Magnetic resonance imaging and computed tomography scan showed a normal-sized pituitary gland entirely embedded in a dense, oedematous, contrast-enhancing mass, and a total destruction of the nasal septum with the absence of conchae and severely impaired sinus walls. A transnasal biopsy showed an acute necrotising, non-specific and non-granulomatous inflammation. Although cocaine-induced panhypopituitarism was suspected, Wegener's granulomatosis could not be excluded. Serology on ANCA showed a strongly positive C-ANCA titre (320 U/l) with specificity for HNE. A cocaine-induced HNE-ANCA-associated panhypopituitarism was diagnosed. Our patient was advised to quit using cocaine immediately and was initially treated with glucocorticoids and testosterone, followed by thyroxine. This led to a dramatic clinical response with an increase of appetite, weight gain and regained energy. After 2 years, the patient is well and his ANCA titre is no longer positive. CONCLUSION: We describe the first documented case of cocaine-induced panhypopituitarism associated with HNE-specific ANCA.

Mutations that affect meiosis in male mice influence the dynamics of the mid-preleptotene and bouquet stages.

Meiosis pairs and segregates homologous chromosomes and thereby forms haploid germ cells to compensate the genome doubling at fertilization. Homologue pairing in many eukaryotic species depends on formation of DNA double strand breaks (DSBs) during early prophase I when telomeres begin to cluster at the nuclear periphery (bouquet stage). By fluorescence in situ hybridization criteria, we observe that mid-preleptotene and bouquet stage frequencies are altered in male mice deficient for proteins required for recombination, ubiquitin conjugation and telomere length control. The generally low frequencies of mid-preleptotene spermatocytes were significantly increased in male mice lacking recombination proteins SPO11, MEI1, MLH1, KU80, ubiquitin conjugating enzyme HR6B, and in mice with only one copy of the telomere length regulator Terf1. The bouquet stage was significantly enriched in Atm(-/-), Spo11(-/-), Mei1(m1Jcs/m1Jcs), Mlh1(-/-), Terf1(+/-) and Hr6b(-/-) spermatogenesis, but not in mice lacking recombination proteins DMC1 and HOP2, the non-homologous end-joining DNA repair factor KU80 and the ATM downstream effector GADD45a. Mice defective in spermiogenesis (Tnp1(-/-), Gmcl1(-/-), Asm(-/-)) showed wild-type mid-preleptotene and bouquet frequencies. A low frequency of bouquet spermatocytes in Spo11(-/-)Atm(-/-) spermatogenesis suggests that DSBs contribute to the Atm(-/-)-correlated bouquet stage exit defect. Insignificant changes of bouquet frequencies in mice with defects in early stages of DSB repair (Dmc1(-/-), Hop2(-/-)) suggest that there is an ATM-specific influence on bouquet stage duration. Altogether, it appears that several pathways influence telomere dynamics in mammalian meiosis.

The functionality and reliability of an Internet interface for assessments of endoscopic still images and video clips: distributed research in gastroenterology.

BACKGROUND: Validation studies of medical images are required before the general use of new imaging techniques, and they necessitate a substantial number of observers. Multicenter studies are desirable but the logistic challenges are considerable. OBJECTIVE: The aim of the present study was to develop and test the functionality and reliability of an Internet interface for distributed evaluation of endoscopic still images and video clips. DESIGN: An Internet site for assessment of endoscopic still images and video clips was developed. To avoid limitations of the bandwidth, a solution was developed to launch and score high-quality video clips on digital video disks (DVDs) from the Internet interface. SETTING: Fifty-five observers were enrolled in the randomized, prospective multicenter study of still images. The feasibility study of video clips included 7 observers. PATIENTS: Four patients presenting with various degree of ulcerative colitis, ranging from normal to severe, were included. MAIN OUTCOME MEASUREMENTS: We tested the reliability of the interface by dual-image assessment, as well as the feasibility of Internet assessment of endoscopic images. We physically distributed high-quality DVD video footage. RESULTS: We recorded 2084 assessments of endoscopic still images and 35 assessments of video clips. The reliability of the Internet interface was confirmed by adequate repeatability and intraobserver agreement of the assessments. Video clips running from a DVD were also successfully shown on the Internet interface. Thus, high-quality video may be assessed independently of the Internet bandwidth. CONCLUSIONS: The present Internet-based tool is functional, efficient, and reliable for high-volume assessment of endoscopic images and video clips.

[Autochthonous babesiosis in dogs in The Netherlands associated with local Dermacentor reticulatus ticks]. / Autochtone babesiose bij de hond in Nederland geassocieerd met lokale Dermacentor reticulatus teken.

In the spring and autumn of 2004, 20 respectively 3 cases of autochthonous canine babesiosis were diagnosed in the Netherlands, four of which ended fatally. Adult Dermacentor reticulatus ticks were found on four dogs. Case descriptions and diagnostics of this B. canis outbreak are discussed in more detail.

Telomere-related genome instability in cancer.

Genome instability is a hallmark of most human cancers. Although a mutator phenotype is not required for tumorigenesis, it can foster mutations that promote tumor progression. Indeed, several inherited cancer-prone syndromes are due to mutations in DNA repair pathways. However, sporadic tumors are usually proficient in DNA repair, making it unlikely that unrepaired lesions are a major source of genome instability in sporadic cancers. A decade ago, I argued in another CSHL Press publication that a "collapse in telomere function can explain a significant portion of the genetic instability in tumors" (de Lange 1995). Since that time, the structure of mammalian telomeres has been analyzed, the consequences of telomere dysfunction have been determined, a mouse model for cancer-relevant aspects of telomere biology has been developed, and the nature and magnitude of cancer genome rearrangements have been revealed. In light of these developments, this is an opportune time to revisit the conjecture that telomere dysfunction contributes to genome instability in human cancer.

Standardization and quality of endoscopy text reports in ulcerative colitis.

BACKGROUND AND STUDY AIMS: The text report is the primary tool for documenting endoscopic findings but there is no consensus on the content and structure of these reports. Therefore, at four Norwegian hospitals, the content of endoscopy reports concerning ulcerative colitis was assessed. Quality indices for the medical history of active ulcerative colitis and endoscopic signs of inflammation were determined, as well as technical items in the report. The effect of structured compared with free-text reporting was evaluated. MATERIALS AND METHODS: Endoscopy reports in 445 cases of ulcerative colitis were retrieved. Two of the hospitals used a semi-structured computerized documentation system, and two hospitals used transcription-based free-text reports. RESULTS: A substantial amount of information was missing in the majority of the reports. Individual endoscopic signs of inflammation were defined in 27 % - 77 % of the reports. Various clinical symptoms of active ulcerative colitis were defined in 1 % - 44 % of the reports. We observed a reminder effect of structured systems in that they prompted more informative reports. There was a tendency towards better free-text documentation in the transcription-based systems than in the free text of the semi-structured ones. CONCLUSIONS: There is a potential for improving the content, completeness and standardization of endoscopy reports. Standardization efforts may be a part of the solution.

T-loop assembly in vitro involves binding of TRF2 near the 3' telomeric overhang.

Mammalian telomeres contain a duplex TTAGGG-repeat tract terminating in a 3' single-stranded overhang. TRF2 protein has been implicated in remodeling telomeres into duplex lariats, termed t-loops, in vitro and t-loops have been isolated from cells in vivo. To examine the features of the telomeric DNA essential for TRF2-promoted looping, model templates containing a 500 bp double-stranded TTAGGG tract and ending in different single-stranded overhangs were constructed. As assayed by electron microscopy, looped molecules containing most of the telomeric tract are observed with TRF2 at the loop junction. A TTAGGG-3' overhang of at least six nucleotides is required for loop formation. Termini with 5' overhangs, blunt ends or 3' termini with non-telomeric sequences at the junction are deficient in loop formation. Addition of non-telomeric sequences to the distal portion of a 3' overhang beginning with TTAGGG repeats only modestly diminishes looping. TRF2 preferentially localizes to the junction between the duplex repeats and the single-stranded overhang. Based on these findings we suggest a model for the mechanism by which TRF2 remodels telomeres into t-loops.

NMR structure of the hRap1 Myb motif reveals a canonical three-helix bundle lacking the positive surface charge typical of Myb DNA-binding domains.

Mammalian telomeres are composed of long tandem arrays of double-stranded telomeric TTAGGG repeats associated with the telomeric DNA-binding proteins, TRF1 and TRF2. TRF1 and TRF2 contain a similar C-terminal Myb domain that mediates sequence-specific binding to telomeric DNA. In the budding yeast, telomeric DNA is associated with scRap1p, which has a central DNA-binding domain that contains two structurally related Myb domains connected by a long linker, an N-terminal BRCT domain, and a C-terminal RCT domain. Recently, the human ortholog of scRap1p (hRap1) was identified and shown to contain a BRCT domain and an RCT domain similar to scRap1p. However, hRap1 contained only one recognizable Myb motif in the center of the protein. Furthermore, while scRap1p binds telomeric DNA directly, hRap1 has no DNA-binding ability. Instead, hRap1 is tethered to telomeres by TRF2. Here, we have determined the solution structure of the Myb domain of hRap1 by NMR. It contains three helices maintained by a hydrophobic core. The architecture of the hRap1 Myb domain is very close to that of each of the Myb domains from TRF1, scRap1p and c-Myb. However, the electrostatic potential surface of the hRap1 Myb domain is distinguished from that of the other Myb domains. Each of the minimal DNA-binding domains, containing one Myb domain in TRF1 and two Myb domains in scRap1p and c-Myb, exhibits a positively charged broad surface that contacts closely the negatively charged backbone of DNA. By contrast, the hRap1 Myb domain shows no distinct positive surface, explaining its lack of DNA-binding activity. The hRap1 Myb domain may be a member of a second class of Myb motifs that lacks DNA-binding activity but may interact instead with other proteins. Other possible members of this class are the c-Myb R1 Myb domain and the Myb domains of ADA2 and Adf1. Thus, while the folds of all Myb domains resemble each other closely, the function of each Myb domain depends on the amino acid residues that are located on the surface of each protein.

Structure of the TRFH dimerization domain of the human telomeric proteins TRF1 and TRF2.

TRF1 and TRF2 are key components of vertebrate telomeres. They bind to double-stranded telomeric DNA as homodimers. Dimerization involves the TRF homology (TRFH) domain, which also mediates interactions with other telomeric proteins. The crystal structures of the dimerization domains from human TRF1 and TRF2 were determined at 2.9 and 2.2 A resolution, respectively. Despite a modest sequence identity, the two TRFH domains have the same entirely alpha-helical architecture, resembling a twisted horseshoe. The dimerization interfaces feature unique interactions that prevent heterodimerization. Mutational analysis of TRF1 corroborates the structural data and underscores the importance of the TRFH domain in dimerization, DNA binding, and telomere localization. A possible structural homology between the TRFH domain of fission yeast telomeric protein Taz1 with those of the vertebrate TRFs is suggested.

t-loops at trypanosome telomeres.

Mammalian telomeres form large duplex loops (t-loops) that may sequester chromosome ends by invasion of the 3' TTAGGG overhang into the duplex TTAGGG repeat array. Here we document t-loops in Trypanosoma brucei, a kinetoplastid protozoan with abundant telomeres due to the presence of many minichromosomes. These telomeres contained 10-20 kb duplex TTAGGG repeats and a 3' TTAGGG overhang. Electron microscopy of psoralen/UV cross-linked DNA revealed t-loops in enriched telomeric restriction fragments and at the ends of isolated minichromosomes. In mammals, t-loops are large (up to 25 kb), often comprising most of the telomere. Despite similar telomere lengths, trypanosome t-loops were much smaller (approximately 1 kb), indicating that t-loop sizes are regulated. Coating of non-cross-linked minichromosomes with Escherichia coli single-strand binding protein (SSB) often revealed 3' overhangs at both telomeres and several cross-linked minichromosomes had t-loops at both ends. These results suggest that t-loops and their prerequisite 3' tails can be formed on the products of both leading and lagging strand synthesis. We conclude that t-loops are a conserved feature of eukaryotic telomeres.

Mammalian meiotic telomeres: protein composition and redistribution in relation to nuclear pores.

Mammalian telomeres consist of TTAGGG repeats, telomeric repeat binding factor (TRF), and other proteins, resulting in a protective structure at chromosome ends. Although structure and function of the somatic telomeric complex has been elucidated in some detail, the protein composition of mammalian meiotic telomeres is undetermined. Here we show, by indirect immunofluorescence (IF), that the meiotic telomere complex is similar to its somatic counterpart and contains significant amounts of TRF1, TRF2, and hRap1, while tankyrase, a poly-(ADP-ribose)polymerase at somatic telomeres and nuclear pores, forms small signals at ends of human meiotic chromosome cores. Analysis of rodent spermatocytes reveals Trf1 at mouse, TRF2 at rat, and mammalian Rap1 at meiotic telomeres of both rodents. Moreover, we demonstrate that telomere repositioning during meiotic prophase occurs in sectors of the nuclear envelope that are distinct from nuclear pore-dense areas. The latter form during preleptotene/leptotene and are present during entire prophase I.

Tankyrase promotes telomere elongation in human cells.

Human telomeres are maintained by telomerase, a reverse transcriptase that adds telomeric repeats to chromosome ends [1,2]. In human tumors and immortalized cells, telomeres are often maintained at a constant length setting [3,4], indicating that telomerase-mediated telomere elongation is tightly regulated. Tankyrase, a telomeric poly(ADP-ribose) polymerase (PARP) [5], was identified through its interaction with TRF1 [6], a negative regulator of telomere extension by telomerase [7]. Tankyrase-mediated ADP-ribosylation inhibits binding of TRF1 to telomeric repeats in vitro [5], suggesting that tankyrase might regulate TRF1 and therefore control telomere dynamics in vivo. Here, we present evidence that tankyrase acts as a positive regulator of telomere elongation in vivo, apparently by inhibiting TRF1. Overexpression of tankyrase in the nucleus diminished the level of unmodified TRF1 in immunoblots and led to reduced immunofluorescence of TRF1 at interphase telomeres. Long-term overexpression of tankyrase in telomerase-positive human cells resulted in a gradual and progressive elongation of telomeres. A PARP-deficient form of tankyrase failed to affect TRF1 and did not alter telomere length dynamics, consistent with ADP-ribosylation of TRF1 as the main cause of altered telomere homeostasis. Our results indicate that tankyrase can induce telomere elongation in human cells. We propose that tankyrase-mediated ADP-ribosylation of TRF1 opens the telomeric complex, allowing access to telomerase.

Cell-cycle-regulated association of RAD50/MRE11/NBS1 with TRF2 and human telomeres.

Telomeres allow cells to distinguish natural chromosome ends from damaged DNA and protect the ends from degradation and fusion. In human cells, telomere protection depends on the TTAGGG repeat binding factor, TRF2 (refs 1-4), which has been proposed to remodel telomeres into large duplex loops (t-loops). Here we show by nanoelectrospray tandem mass spectrometry that RAD50 protein is present in TRF2 immunocomplexes. Protein blotting showed that a small fraction of RAD50, MRE11 and the third component of the MRE11 double-strand break (DSB) repair complex, the Nijmegen breakage syndrome protein (NBS1), is associated with TRF2. Indirect immunofluorescence demonstrated the presence of RAD50 and MRE11 at interphase telomeres. NBS1 was associated with TRF2 and telomeres in S phase, but not in G1 or G2. Although the MRE11 complex accumulated in irradiation-induced foci (IRIFs) in response to gamma-irradiation, TRF2 did not relocate to IRIFs and irradiation did not affect the association of TRF2 with the MRE11 complex, arguing against a role for TRF2 in DSB repair. Instead, we propose that the MRE11 complex functions at telomeres, possibly by modulating t-loop formation.