bluuebunny/crossref_metadata_2025 huggingface dataset:
Attitudes of young people with diabetes to an Internet-based virtual clinic
Authors: Lowe Pam , Hearnshaw Hilary , Griffiths Frances
Published: July 2005

We assessed the feasibility of developing a virtual diabetes clinic for young people, using the Internet. The proposed content of the site would be based on self-efficacy theory, aiming to develop confidence in self-management of diabetes. A questionnaire about the proposed Website was delivered to 72 patients who attended a young person's outpatient clinic in a district hospital. Thirty-nine replies were received, a response rate of 54%. The mean age of the respondents was 1 3 years. A positive attitude to the potential clinic was reported by 95% of respondents. The items rated as most useful were: quick and easy access to up-to-date information about diabetes; the opportunity to ask an expert; good graphics; easy navigation; interactivity. Responses to open questions indicated that 24–hour access and anonymity in asking questions were also valued. A virtual clinic appears to be a possible method of health-care delivery to young people with diabetes.
Principles for telemedicine and telecare: The perspective of a citizens’ panel
Authors: Mort Maggie , Finch Tracy
Published: July 2005

Ten delegates at the conference Voluntarism, Health and Social Care were recruited to form a panel of citizens to debate and offer direction for the future of technologically mediated health care. The panel suggested various principles for the development of telemedicine and telecare, concerning: patients, users and carers, approach to service delivery, research and knowledge, and conditions of use. Many of the principles echoed the founding values of the National Health Service, yet have arguably been absent from both policy pronouncements and the telemedicine literature, which largely views new health technologies themselves as ‘value free’, i.e. developed untouched by social and political relations. A programme of citizens’ panels should be developed so that an informed debate can take place about the development of telemedicine and telecare, to underpin policy and practice.
Implementing autonomy in a diabetes management system
Authors: Black Lesley-Ann , Mcmeel Conor , Mctear Michael , Black Norman , Harper Roy , Lemon Michelle
Published: July 2005

We have developed a speech-based telemedicine system which enables patients with hypertension and type 2 diabetes mellitus to send frequent, home-monitored health data via the telephone to the point of care. The decision support module in the system was tested using data from a cohort of 10 patients generated over a two-year period. Results from the tests indicate that the system is effective in providing personalized feedback to the patient and in generating alerts for the clinical user. The work suggests that this method of care delivery is practical, informative, and may improve the efficiency of chronic health-care delivery by reducing costs and improving patient-physician communication between hospital visits.
A Web-based intervention used in general practice for people with excessive alcohol consumption
Authors: Linke S , Harrison R , Wallace P
Published: July 2005

Down Your Drink is a Web-based brief intervention for hazardous drinkers. We conducted a pilot study of its usefulness in general practice. Visitors to the Website were invited to complete the Fast Alcohol Screening Test and positive responders were offered a six-week interactive Web-based programme. There were 1 319 registrations in the six-month study period. In all, 815 (62%) registrants completed week one, and 79 (6%) stayed with the programme until the end. Usage of the Website was distributed through the day, with the highest levels between 10:00 and 14:00. Two focus groups with general practitioners were conducted to explore the potential for using the site in primary-care settings. Website interventions for excessive drinkers therefore appear to be feasible and may prove a useful additional tool for intervention in general practice.
Diffusion theory and telemedicine adoption by Kansas health-care providers: Critical factors in telemedicine adoption for improved patient access
Authors: Spaulding Ryan J , Russo Tracy , Cook David J , Doolittle Gary C
Published: July 2005

Twenty counties in Kansas were randomly selected from those designated as rural on the basis of their populations. A sample of 356 physicians and physicians’ assistants in these counties was chosen. A postal survey was sent to the identified providers up to three times. One hundred and eighty-six of the questionnaires were returned (a response rate of 52%). In all, 76% of the respondents were physicians, 76% were men and 42% were family practitioners. Practitioners were classified as adopters or non-adopters of telemedicine, based on their report of whether they had ever referred one or more patients for a health-care consultation via telemedicine. Of the 167 participants who marked this item, 30 (18%) were adopters and 1 37 (82%) were non-adopters. Among the adopters, 16 (53%) said that they expected to use telemedicine with about the same frequency or more often in the future. In contrast, 61 (45%) non-adopters reported that they did not expect to refer patients by telemedicine in the future and 51 (37%) were unsure. Neither age (r=0.16, P = 0.44) nor gender (χ2 = 2.35, P = 0.1 3) was related to the adoption variable or the number of referrals made to telemedicine clinics. The results suggest that adopters and non-adopters of telemedicine perceive its value very differently, and that an opportunity exists to promote the concept to non-adopters more effectively.
Cardiac event recording yields more diagnoses than 24–hour Holter monitoring in patients with palpitations
Authors: Scalvini S , Zanelli E , Martinelli G , Baratti D , Giordano A , Glisenti F
Published: July 2005

Palpitation is a common symptom that sometimes results from a substantial cardiac arrhythmia. We compared the diagnostic yield of trans-telephonic event monitors with those of Holter monitoring in patients with intermittent palpitations. In all, 310 patients were randomly assigned to receive an event recorder or 24–hour Holter monitoring. Event recorders were used for seven days or until two recordings were obtained while symptoms occurred. The main end-point was an electrocardiogram (ECG) recorded during symptoms. The patients with palpitation recorded the one-lead ECG trace and sent it to a telemedicine call centre, where a nurse responded. There were 119 symptomatic patients in the event recorder group and 74 in the Holter group. The total costs were €6019 for event recording and €9605 for Holter monitoring. The average costs were €51 per symptomatic patient detected by event recorder monitoring and €1 30 per symptomatic patient detected by Holter monitoring. More patients therefore received a clear diagnosis, and more quickly, when using event recording than with Holter monitoring. For this reason, event recorders are preferable to Holter monitors for patients with palpitations.
A Brazilian model of distance education in physical medicine and rehabilitation based on videoconferencing and Internet learning
Authors: Kavamoto Cristianne Akie , Wen Chao Lung , Battistella Linamara Rizzo , Böhm György Miklós
Published: July 2005

We have developed an integrated educational model in rehabilitation mediated by technology. Three teams of professionals worked to implement the interactive model based on videoconferencing, use of the Internet and three-dimensional (3–D) animated models. Two courses were created: amputee rehabilitation and back pain. Each course was divided into four phases: (1) a first videoconference; (2) Internet-based learning; (3) a second videoconference (workshop); (4) an Internet discussion list. The Internet-based learning modules were divided into topics by multiple-choice questions. Multisite videoconferences were used to connect the remote sites. Eleven animated 3–D models were created to help the teaching process. Each course had 11 modules, and each module required up to 2 h to be completed. There were 1 36 participants on the two courses. None of the participants, including the teachers, had had any previous experience with Internet-based learning and videoconferencing. The integrated educational model has great potential in a country the size of Brazil, where there may be difficulties in travel for patients with disabilities and for health-care professionals.
The efficacy of telemedicine for ophthalmology triage by a general practitioner
Authors: Taleb Alexandre Chater , Böhm György M , Avila Marcos , Wen Chao Lung
Published: July 2005

Although there are enough ophthalmologists for the Brazilian population, they are not evenly distributed throughout the country. Tele-ophthalmology may therefore be a useful tool. We have examined the feasibility of ophthalmology triage, performed by a general practitioner (GP) with remote support from an ophthalmologist. Forty patients with a variety of external and internal eye disorders were examined by the GP and also reassessed by an ophthalmologist, face to face, and then remotely by another ophthalmologist. There was agreement in 95% of the diagnoses between face-to-face and distant evaluation. The use of a digital camera and slit-lamp allowed greater accuracy of telediagnosis than the use of a digital camera alone. The GP would have referred 36 patients to an ophthalmologist, while both the local and the remote ophthalmologist saw the need for referral in 31 cases, i.e. assessment by tele-ophthalmology resulted in a 14% decrease in referrals. GP triage therefore appears to be feasible after appropriate training.
Wellness management through Web-based programmes
Authors: Omar A , Wahlqvist M L , Kouris-Blazos A , Vicziany M
Published: July 2005

We established a Web-based programme called the ‘Wellness Online Program’ or WOLP. The programme runs for six weeks. It aims to help individuals manage their own wellness regardless of geographical location. WOLP is based on a holistic approach to health and consists of six wellness dimensions: physical (exercise and diet), emotional, social, intellectual, spiritual and occupational. A total of 150 volunteers from the general public were recruited online for this study and data were collected at three intervals: at the beginning of the programme (week 1), mid-programme (week 3) and at the end of the programme (week 6). Ninety of the participants (60%) completed the six-week programme. Acceptance of WOLP, measured by the frequency of individual usage, increased from the start to the end of the programme. Overall personal wellness management improved after six weeks on the wellness programme (5–10%). The study shows that personal wellness management, which had been demonstrated in the narrower confines of the corporate sector, is also possible in the public domain.
Adapting the Roter interaction analysis system for telemedicine: Lessons from four specialty clinics
Authors: Nelson Eve-Lynn , Spaulding Ryan
Published: July 2005

Four specialists (a child psychiatrist, an oncologist, a cardiologist and a rheumatologist) conducted telemedicine clinics using videoconferencing at a bandwidth of 128–384 kbit/s. The consultations were videorecorded. The coded interactions from the first two patients recruited from each of the four telemedicine clinics were analysed. Tapes were coded by two raters. We adapted the Roter interaction analysis system (RIAS) for the telemedicine context. Utterances were coded into socio-emotional and task-focused categories. There were 1055 utterances in total. Providers generated significantly more utterances across categories than patients. In the patient-provider interactions, only 2% of the total utterances related to the technology. The predominance of socio-emotional utterances compared with task-focused utterances for providers was contrary to our expectations. Further studies are required to establish the reliability of the adapted RIAS measure and to increase understanding of telemedicine communication patterns.
Challenges in Detecting the Abuse of Growth Hormone in Sport
Authors: McHugh Cathy M , Park Roderick T , Sönksen Peter H , Holt Richard IG
Published: July 2005

Background: Growth hormone (GH) is reputed to be in widespread use in the sporting arena as a performance-enhancing agent and is on the list of banned substances published by the World Anti-Doping Agency. The detection of GH abuse poses many challenges. Unlike many substances of abuse, such as synthetic anabolic steroids, GH is a naturally occurring substance; therefore, demonstration of exogenous administration must rely on detecting concentrations in excess of an established reference interval. The purpose of this review is to discuss the methodologies being developed to detect GH abuse.

Methods: We undertook a comprehensive search using multiple electronic databases and hand searches of reference lists of articles. The data for this review reflect our academic interests and experience through work on the GH-2000 and GH-2004 projects.

Results: Two approaches have been taken to detect GH abuse. The first is based on assessment of the effect of exogenous GH on pituitary GH isoforms, and the second is based on measurement of markers of GH action. The advantages of each approach and the difficulties encountered with each technique, as well as future concepts in detection, are discussed.

Conclusion: Although there are substantial challenges for the detection of GH, methodologies now exist to detect GH abuse with reasonable sensitivity and specificity.
Use of Protein:Creatinine Ratio Measurements on Random Urine Samples for Prediction of Significant Proteinuria: A Systematic Review
Authors: Price Christopher P , Newall Ronald G , Boyd James C
Published: July 2005

Background: Proteinuria is recognized as an independent risk factor for cardiovascular and renal disease and as a predictor of end organ damage. The reference test, a 24-h urine protein estimation, is known to be unreliable. A random urine protein:creatinine ratio has been shown to correlate with a 24-h estimation, but it is not clear whether it can be used to reliably predict the presence of significant proteinuria.

Methods: We performed a systematic review of the literature on measurement of the protein:creatinine ratio on a random urine compared with the respective 24-h protein excretion. Likelihood ratios were used to determine the ability of a random urine protein:creatinine ratio to predict the presence or absence of proteinuria.

Results: Data were extracted from 16 studies investigating proteinuria in several settings; patient groups studied were primarily those with preeclampsia or renal disease. Sensitivities and specificities for the tests ranged between 69% and 96% and 41% and 97%, respectively, whereas the positive and negative predictive values ranged between 46% and 95% and 45% and 98%, respectively. The positive likelihood ratios ranged between 1.8 and 16.5, and the negative likelihood ratios between 0.06 and 0.35. The cumulative negative likelihood ratio for 10 studies on proteinuria in preeclampsia was 0.14 (95% confidence interval, 0.09–0.24).

Conclusion: The protein:creatinine ratio on a random urine specimen provides evidence to “rule out” the presence of significant proteinuria as defined by a 24-h urine excretion measurement.
Clinical Restenosis after Coronary Stent Implantation Is Associated with the Heme Oxygenase-1 Gene Promoter Polymorphism and the Heme Oxygenase-1 +99G/C Variant
Authors: Gulesserian Talin , Wenzel Catharina , Endler Georg , Sunder-Plassmann Raute , Marsik Claudia , Mannhalter Christine , Iordanova Nelly , Gyöngyösi Mariann , Wojta Johann , Mustafa Stefan , Wagner Oswald , Huber Kurt
Published: July 2005

Background: Vascular remodeling after percutaneous coronary stent implantation frequently leads to restenosis. Heme oxygenase 1 (HO-1) is involved in the generation of the endogenous antioxidant bilirubin and carbon monoxide, both of which exert antiinflammatory and antiproliferative effects. The aim of the present study was to evaluate the influence of genetic risk factors combined with the conventional risk factors on the development of coronary restenosis after percutaneous coronary intervention (PCI) with stent implantation.

Methods: The HO-1 gene GT dinucleotide repeat promoter polymorphism and HO-1 +99G/C variant were evaluated in 199 patients with coronary artery disease after coronary stent implantation and control angiography at 6 months after the intervention. Coronary restenosis was confirmed by quantitative angiography.

Results: Carriers of the long allele of the HO-1 gene promoter (>29 repeats) had a significantly higher risk of developing restenosis after PCI than noncarriers [odds ratio (OR) = 1.9; 95% confidence interval (95% CI), 1.0–3.4; P = 0.04]. Interestingly, the allele longer than 29 repeats conferred a significantly higher risk of developing restenosis (OR = 3.4; 95% CI, 1.2–9.1; P = 0.017) in nonsmokers than in smokers (OR = 2.0; 95% CI, 0.7–5.2; P = 0.18).

Conclusions: The long allele of the HO-1 gene promoter (>29 repeats) polymorphism, which leads to low HO-1 inducibility, may represent an independent prognostic marker for restenosis after PCI and stent implantation. The effect of the >29 repeat allele is attenuated in smokers, who have chronic exogenous CO exposure.
Separation of β2-Transferrin by Denaturing Gel Electrophoresis to Detect Cerebrospinal Fluid in Ear and Nasal Fluids
Authors: Görögh Tibor , Rudolph Pierre , Meyer Jens Eduard , Werner Jochen A , Lippert Burkard M , Maune Steffen
Published: July 2005

Background: Cerebrospinal fluid (CSF) leakage is a critical condition with a substantial risk of meningitis. We investigated the use of transferrin isoform analysis as a diagnostic marker for detection of CSF leakage in fluid samples.

Methods: We analyzed 241 samples from patients with CSF leakage, most commonly presenting as otorrhea or rhinorrhea, by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) with subsequent Western blotting and immunostaining for transferrin. Tears, saliva, nasal fluid, and ear secretions (20 samples each) were analyzed in parallel, and normal human serum served as a control in each experiment. We compared the minimum volume of added CSF that could be detected in secretions by our assay with the minimum volume detected by the prostaglandin-D synthase (β-trace) test. CSF was admixed with blood in different proportions to determine the influence of blood contamination on the transferrin pattern.

Results: In all CSF samples, β1- and β2-transferrin were present in nearly equal amounts. In tears and ear secretions, β2-transferrin migrated in the gel in the same manner as in CSF, but its concentration was noticeably lower than that of β1-transferrin, a difference that allowed a clear distinction from the transferrin pattern of CSF. In saliva, both transferrin isoforms were also present but could be distinguished from those of other fluids by electrophoretic migration pattern rather than relative concentrations. With the β-trace test, a minimum of 5 μL of CSF was needed for detection, whereas our β2-transferrin assay yielded a signal of comparable intensity with a minimum of 2 μL of CSF.

Conclusion: Analysis of the transferrin microheterogeneity pattern by SDS-PAGE for the identification of CSF leakage is a highly sensitive and specific method that merits consideration as a routine technique.
Genomewide Scan for Anal Atresia in Swine Identifies Linkage and Association With a Chromosome Region onSus scrofaChromosome 1
Authors: Wiedemann Sabine , Fries Ruedi , Thaller Georg
Published: July 2005

Anal atresia is a rare and severe disorder in swine occurring with an incidence of 0.1–1.0%. A whole-genome scan based on affected half-sibs was performed to identify susceptibility loci for anal atresia. The analysis included 27 families with a total of 95 animals and 65 affected piglets among them. Animals were genotyped for 126 microsatellite markers distributed across the 18 autosomal porcine chromosomes and the X chromosome, covering an estimated 2080 cM. Single-point and multipoint nonparametric linkage scores were calculated using the computer package ALLEGRO 1.0. Significant linkage results were obtained for chromosomes 1, 3, and 12. Markers on these chromosomes and additionally on chromosomes for which candidate genes have been postulated in previous studies were subjected to the transmission disequilibrium test (TDT). The test statistic exceeded the genomewide significance level for adjacent markers SW1621 (P = 7 × 10−7) and SW1902 (P = 3 × 10−3) on chromosome 1, supporting the results of the linkage analysis. A specific haplotype associated with anal atresia that could prove useful for selection against the disorder was revealed. Suggestive linkage and association were also found for markers S0081 on chromosome 9 and SW957 on chromosome 12.
Update on Estimation of Mutation Rates Using Data From Fluctuation Experiments
Authors: Zheng Qi
Published: July 2005

This note discusses a minor mathematical error and a problematic mathematical assumption in Luria and Delbrück's (1943) classic article on fluctuation analysis. In addition to suggesting remedial measures, the note provides information on the latest development of techniques for estimating mutation rates using data from fluctuation experiments.
Multiple Signatures of Positive Selection Downstream of Notch on the X Chromosome in Drosophila melanogaster
Authors: DuMont Vanessa Bauer , Aquadro Charles F
Published: July 2005

To identify genomic regions affected by the rapid fixation of beneficial mutations (selective sweeps), we performed a scan of microsatellite variability across the Notch locus region of Drosophila melanogaster. Nine microsatellites spanning 60 kb of the X chromosome were surveyed for variation in one African and three non-African populations of this species. The microsatellites identified an ∼14-kb window for which we observed relatively low levels of variability and/or a skew in the frequency spectrum toward rare alleles, patterns predicted at regions linked to a selective sweep. DNA sequence polymorphism data were subsequently collected within this 14-kb region for three of the D. melanogaster populations. The sequence data strongly support the initial microsatellite findings; in the non-African populations there is evidence of a recent selective sweep downstream of the Notch locus near or within the open reading frames CG18508 and Fcp3C. In addition, we observe a significant McDonald-Kreitman test result suggesting too many amino acid fixations species wide, presumably due to positive selection, at the unannotated open reading frame CG18508. Thus, we observe within this small genomic region evidence for both recent (skew toward rare alleles in non-African populations) and recurring (amino acid evolution at CG18508) episodes of positive selection.
Evidence of a Major Gene From Bayesian Segregation Analyses of Liability to Osteochondral Diseases in Pigs
Authors: Kadarmideen Haja N , Janss Luc L G
Published: July 2005

Bayesian segregation analyses were used to investigate the mode of inheritance of osteochondral lesions (osteochondrosis, OC) in pigs. Data consisted of 1163 animals with OC and their pedigrees included 2891 animals. Mixed-inheritance threshold models (MITM) and several variants of MITM, in conjunction with Markov chain Monte Carlo methods, were developed for the analysis of these (categorical) data. Results showed major genes with significant and substantially higher variances (range 1.384–37.81), compared to the polygenic variance ($\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{{\sigma}}_{\mathrm{u}}^{2}\) \end{document}$). Consequently, heritabilities for a mixed inheritance (range 0.65–0.90) were much higher than the heritabilities from the polygenes. Disease allele frequencies range was 0.38–0.88. Additional analyses estimating the transmission probabilities of the major gene showed clear evidence for Mendelian segregation of a major gene affecting osteochondrosis. The variants, MITM with informative prior on $\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{{\sigma}}_{\mathrm{u}}^{2}\) \end{document}$, showed significant improvement in marginal distributions and accuracy of parameters. MITM with a “reduced polygenic model” for parameterization of polygenic effects avoided convergence problems and poor mixing encountered in an “individual polygenic model.” In all cases, “shrinkage estimators” for fixed effects avoided unidentifiability for these parameters. The mixed-inheritance linear model (MILM) was also applied to all OC lesions and compared with the MITM. This is the first study to report evidence of major genes for osteochondral lesions in pigs; these results may also form a basis for underpinning the genetic inheritance of this disease in other animals as well as in humans.
Segmental Structure of the Brassica napus Genome Based on Comparative Analysis With Arabidopsis thaliana
Authors: Parkin Isobel A P , Gulden Sigrun M , Sharpe Andrew G , Lukens Lewis , Trick Martin , Osborn Thomas C , Lydiate Derek J
Published: July 2005

Over 1000 genetically linked RFLP loci in Brassica napus were mapped to homologous positions in the Arabidopsis genome on the basis of sequence similarity. Blocks of genetically linked loci in B. napus frequently corresponded to physically linked markers in Arabidopsis. This comparative analysis allowed the identification of a minimum of 21 conserved genomic units within the Arabidopsis genome, which can be duplicated and rearranged to generate the present-day B. napus genome. The conserved regions extended over lengths as great as 50 cM in the B. napus genetic map, equivalent to ∼9 Mb of contiguous sequence in the Arabidopsis genome. There was also evidence for conservation of chromosome landmarks, particularly centromeric regions, between the two species. The observed segmental structure of the Brassica genome strongly suggests that the extant Brassica diploid species evolved from a hexaploid ancestor. The comparative map assists in exploiting the Arabidopsis genomic sequence for marker and candidate gene identification within the larger, intractable genomes of the Brassica polyploids.
Quantitative Trait Locus Analysis of Longitudinal Quantitative Trait Data in Complex Pedigrees
Authors: Macgregor Stuart , Knott Sara A , White Ian , Visscher Peter M
Published: July 2005

There is currently considerable interest in genetic analysis of quantitative traits such as blood pressure and body mass index. Despite the fact that these traits change throughout life they are commonly analyzed only at a single time point. The genetic basis of such traits can be better understood by collecting and effectively analyzing longitudinal data. Analyses of these data are complicated by the need to incorporate information from complex pedigree structures and genetic markers. We propose conducting longitudinal quantitative trait locus (QTL) analyses on such data sets by using a flexible random regression estimation technique. The relationship between genetic effects at different ages is efficiently modeled using covariance functions (CFs). Using simulated data we show that the change in genetic effects over time can be well characterized using CFs and that including parameters to model the change in effect with age can provide substantial increases in power to detect QTL compared with repeated measure or univariate techniques. The asymptotic distributions of the methods used are investigated and methods for overcoming the practical difficulties in fitting CFs are discussed. The CF-based techniques should allow efficient multivariate analyses of many data sets in human and natural population genetics.
Blocked Recombination Along the Mating-Type Chromosomes of Neurospora tetrasperma Involves Both Structural Heterozygosity and Autosomal Genes
Authors: Jacobson David J
Published: July 2005

The Neurospora tetrasperma mating-type chromosomes have been shown to be structurally heterozygous by reciprocal introgression of these chromosomes between N. tetrasperma and N. crassa. This structural heterozygosity correlates with both a previously described recombination block and cytologically visible unpaired chromosomes at pachytene. Genes on the autosomes are also implicated in blocking recombination.
Discrepancies Between Recombination Frequencies and Physical Distances in Aspergillus nidulans: Implications for Gene Identification
Authors: Espeso Eduardo A , Cobeño Laura , Arst Herbert N
Published: July 2005

A rapid route to gene molecular identification involves using recombination frequencies in locating mutational sequence changes. We describe a case where the recombination frequency is deceptively low, probably reflecting centromere proximity. Recombination frequencies are greatly reduced near the centromeres on the right arms of chromosomes III and IV of Aspergillus nidulans.
Regulation of Histone Deposition Proteins Asf1/Hir1 by Multiple DNA Damage Checkpoint Kinases in Saccharomyces cerevisiae
Authors: Sharp Judith A , Rizki Gizem , Kaufman Paul D
Published: July 2005

CAF-1, Hir proteins, and Asf1 are histone H3/H4 binding proteins important for chromatin-mediated transcriptional silencing. We explored genetic and physical interactions between these proteins and S-phase/DNA damage checkpoint kinases in the budding yeast Saccharomyces cerevisiae. Although cells lacking checkpoint kinase Mec1 do not display defects in telomeric gene silencing, silencing was dramatically reduced in cells lacking both Mec1 and the Cac1 subunit of CAF-1. Silencing was restored in cac1Δ and cac1Δ mec1Δ cells upon deletion of Rad53, the kinase downstream of Mec1. Restoration of silencing to cac1Δ cells required both Hir1 and Asf1, suggesting that Mec1 counteracts functional sequestration of the Asf1/Hir1 complex by Rad53. Consistent with this idea, the degree of suppression of silencing defects by rad53 alleles correlated with effects on Asf1 binding. Furthermore, deletion of the Dun1 kinase, a downstream target of Rad53, also suppressed the silencing defects of cac1Δ cells and reduced the levels of Asf1 associated with Rad53 in vivo. Loss of Mec1 and Rad53 did not alter telomere lengths or Asf1 protein levels, nuclear localization, or chromosome association. We conclude that the Mec1 and Dun1 checkpoint kinases regulate the Asf1-Rad53 interaction and therefore affect the activity of the Asf1/Hir complex in vivo.
Rmr6 Maintains Meiotic Inheritance of Paramutant States in Zea mays
Authors: Hollick Jay B , Kermicle Jerry L , Parkinson Susan E
Published: July 2005

Paramutation generates heritable changes affecting regulation of specific alleles found at several Zea mays (maize) loci that encode transcriptional regulators of anthocyanin biosynthetic genes. Although the direction and extent of paramutation is influenced by poorly understood allelic interactions occurring in diploid sporophytes, two required to maintain repression loci (rmr1 and rmr2), as well as mediator of paramutation1 (mop1), affect this process at the purple plant1 (pl1) locus. Here we show that the rmr6 locus is required for faithful transmission of weakly expressed paramutant states previously established at both pl1 and red1 (r1) loci. Transcriptional repression occurring at both pl1 and booster1 (b1) loci as a result of paramutation also requires Rmr6 action. Reversions to highly expressed, nonparamutant states at both r1 and pl1 occur in plants homozygous for rmr6 mutations. Pedigree analysis of reverted pl1 alleles reveals variable latent susceptibilities to spontaneous paramutation in future generations, suggesting a quantitative nature of Rmr6-based alterations. Genetic tests demonstrate that Rmr6 encodes a common component required for establishing paramutations at diverse maize loci. Our analyses at pl1 and r1 suggest that this establishment requires Rmr6-dependent somatic maintenance of meiotically heritable epigenetic marks.
A Screen for Nigericin-Resistant Yeast Mutants Revealed Genes Controlling Mitochondrial Volume and Mitochondrial Cation Homeostasis
Authors: Kucejova Blanka , Kucej Martin , Petrezselyova Silvia , Abelovska Lenka , Tomaska Lubomir
Published: July 2005

Little is known about the regulation of ion transport across the inner mitochondrial membrane in Saccharomyces cerevisiae. To approach this problem, we devised a screening procedure for facilitating the identification of proteins involved in mitochondrial ion homeostasis. Taking advantage of the growth inhibition of yeast cells by electroneutral K+/H+ ionophore nigericin, we screened for genetic mutations that would render cells tolerant to this drug when grown on a nonfermentable carbon source and identified several candidate genes including MDM31, MDM32, NDI1, YMR088C (VBA1), CSR2, RSA1, YLR024C, and YNL136W (EAF7). Direct examination of intact cells by electron microscopy indicated that mutants lacking MDM31 and/or MDM32 genes contain dramatically enlarged, spherical mitochondria and that these morphological abnormalities can be alleviated by nigericin. Mitochondria isolated from the Δmdm31 and Δmdm32 mutants exhibited limited swelling in an isotonic solution of potassium acetate even in the presence of an exogenous K+/H+ antiport. In addition, growth of the mutants was inhibited on ethanol-containing media in the presence of high concentrations of salts (KCl, NaCl, or MgSO4) and their mitochondria exhibited two- (Δmdm31 and Δmdm32) to threefold (Δmdm31Δmdm32) elevation in magnesium content. Taken together, these data indicate that Mdm31p and Mdm32p control mitochondrial morphology through regulation of mitochondrial cation homeostasis and the maintenance of proper matrix osmolarity.
Genome‐wide Examination of the Natural Solar Radiation Response in Shewanella oneidensis MR‐1
Authors: Qiu Xiaoyun , Tiedje James M. , Sundin George W.
Published: July 2005

We previously reported that Shewanella oneidensis MR‐1 is extremely sensitive to natural solar radiation (NSR). Here we analyzed the global transcriptional profile of MR‐1 during a 1‐h recovering period after exposure to ambient solar light at a dose that yields about 20% survival rate on a Luria‐Bertani (LB) plate. We observed the induction of DNA damage‐repair genes, the SOS response as well as detoxification strategies that we previously observed in MR‐1 following artificial UV‐A irradiation. Few prophage‐related genes were induced by natural solar UV radiation, however, in contrast to what was observed following artificial UV‐B irradiation. Overall, the cellular response to NSR in MR‐1 was more similar to that of UV‐A than that of UV‐B, but additional genes involved in detoxification were induced compared with induction by either UV‐B or UV‐A or their sum. Thus, oxidative stress appeared to contribute greatly to the NSR‐induced cytotoxic effects in MR‐1. A total of 29.1% of genome showed differential expression following NSR exposure, which is much greater than following exposure by UV‐B (4.0%), UV‐A (8.2%) or their sum (10.7%). Our data suggest that NSR may impact biological processes in a much more complex manner than previously thought.
Vibrational Spectroscopic Studies on the Disulfide Formation and Secondary Conformational Changes of Captopril–HSA Mixture after UV‐B Irradiation
Authors: Li Mei‐Jane , Lin Shan‐Yang
Published: July 2005

The effects of pH and ultraviolet‐B (UV‐B) irradiation on the secondary structure of human serum albumin (HSA) in the absence or presence of captopril were investigated by an attenuated total reflection (ATR)/Fourier transform infrared (FTIR) spectroscopy. The UV‐B exposure affecting the stability of captopril before and after captopril–HSA interaction was also examined by using confocal Raman microspectroscopy. The results indicate that the transparent pale‐yellow solution for captopril–HSA mixture in all pH buffer solutions, except pH 5.0∼7.0, changed into a viscous form then a gel form with UV‐B exposure time. The secondary structural transformation of HSA in the captopril–HSA mixture with or without UV‐B irradiation was found to shift the maxima amide I peak in IR spectra from 1652 cm−1 assigned to α‐helix structure to 1622 cm−1 because of a β‐sheet structure, which was more evident in pH 3.0, 8.0 or 9.0 buffer solutions. The Raman shift from 1653 cm−1 (α‐helix) to 1670 cm−1 (β‐sheet) also confirmed this result. Captopril dissolved in distilled water with or without UV‐B irradiation was determined to form a captopril disulfide observed from the Raman spectra of 512 cm−1, which was exacerbated by UV‐B irradiation. There was little disulfide formation in the captopril–HSA mixture even with long‐term UV‐B exposure, but captopril might interact with HSA to change the protein secondary structure of HSA whether there was UV‐B irradiation or not. The pH of the buffer solution and captopril–HSA interaction may play more important roles in transforming the secondary structure of HSA from α‐helix to β‐sheet in the corresponding captopril–HSA mixture than UV‐B exposure. The present study also implies that HSA has the capability to protect the instability of captopril in the course of UV‐B irradiation. In addition, a partial unfolding of HSA induced by pH or captopril‐HSA interaction under UV‐B exposure is proposed.
Substituent Effects on the Photophysical Properties of Pterin Derivatives in Acidic and Alkaline Aqueous Solutions
Authors: Cabrerizo Franco M. , Petroselli Gabriela , Lorente Carolina , Capparelli Alberto L. , Thomas Andrés H. , Braun André M. , Oliveros Esther
Published: July 2005

Pterins are heterocyclic compounds with important biological functions, and most of them may exist in two acid‐base forms in the pH range between 3 and 13 in aqueous solution. In this work, the photophysical properties of acid and basic forms of six compounds of the pterin family (6‐hydroxymethylpterin [HPT], 6‐methylpterin [MPT], 6,7‐dimethylpterin [DPT], rhamnopterin [RPT], N‐methylfolic acid [MFA], and pteroic acid [PA]) have been studied. The effects of the chemical nature of the substituents at position 6 of the pterin moiety and the effects of the pH on the absorption and emission properties are analyzed. The fluorescence characteristics (spectra, quantum yields, lifetimes) of these compounds have been investigated using the single‐photon‐counting technique. Results obtained for pterin derivatives containing small substituents with 1 carbon atom (HPT, MPT, DPT) and short hydrocarbon chain (4 carbon atoms) (RPT) are different from those found for pterin derivatives containing a p‐aminobenzoic acid (PABA) moiety in the substituent (MFA and PA). Fluorescence quantum yields (φF) of the first group of compounds are relatively high (0.4), whereas MFA and PA exhibit very small φF values (0.01).
Mutational Effects on Protein Structural Changes and Interdomain Interactions in the Blue‐light Sensing LOV Protein YtvA
Authors: Losi Aba , Ghiraldelli Elisa , Jansen Sven , Gärtner Wolfgang
Published: July 2005

Mutagenesis studies on the phototropin‐related protein YtvA from Bacillus subtilis have revealed the role of selected structural elements in interdomain communication. The LOV (light, oxygen, voltage) domain of YtvA undergoes light‐driven reactions similar to that of phot‐LOV, with reversible formation of a covalent flavin‐cysteine adduct. The mutated proteins Ytva‐E105L and YtvA‐E56Q have been studied by UV fluorescence and circular dichroism (CD) spectroscopy. E105 (L in phototropin) is located at the solvent‐exposed surface of the LOV domain central β‐sheet, demonstrated to participate in interdomain interaction in phototropin. CD data show that YtvA‐E105L has a lower α‐helix content in the dark and undergoes larger light‐driven conformational changes than YtvA‐WT. The E56Q mutation breaks the E56‐K97 salt bridge, a structural element highly conserved within the LOV series. In YtvA‐E56Q the CD spectrum is the same as in YtvA‐WT, although the conserved W103 becomes more exposed to the solvent and the dark‐recovery kinetics is slower. These results indicate that the E56‐K97 salt bridge stabilizes locally the protein structure and participates in the regulation of the photocycle but has negligible effects on the overall structure. The E105L mutation, instead, highlights the involvement of the central β‐sheet in the light‐driven conformational changes in LOV proteins.
Transcript Profiling of Periodontal Fibroblasts and Osteoblasts
Authors: Lallier Thomas E. , Spencer Amber , Fowler Melanie M.
Published: July 2005

Background: Fibroblasts are critical to the establishment and maintenance of the periodontal attachment apparatus (cementum, periodontal ligament [PDL], and bone). In order to characterize the cellular changes that accompany periodontal regeneration, better tools are necessary to distinguish periodontal ligament fibroblasts (PDLF), gingival fibroblasts, and osteoblasts. Our goal is to identify gene markers to better characterize and identify these cell types.

Methods: We chose to examine and compare the expression of numerous gene transcripts by semiquantitative reverse transcriptase‐ polymerase chain reaction using primers specific for 44 different gene transcripts in order to better characterize the identity of these cells.

Results: Several transcripts were cell‐type specific. Specifically, fibromodulin was expressed only in PDL fibroblasts, while osteopontin was expressed only in dermal fibroblasts. In addition, lumican was expressed by all three types of fibroblasts (PDL, gingival, and dermal), while alkaline phosphatase was expressed by osteoblasts as well as PDL and gingival fibroblasts.

Conclusions: Our results indicate that PDL fibroblasts are distinct from either gingival or dermal fibroblasts or osteoblasts. In general, PDL and gingival fibroblasts displayed greater similarity to each other than either displayed toward dermal fibroblasts. Furthermore, both gingival and PDL fibroblasts displayed greater similarity to osteoblasts than to dermal fibroblasts, possibly reflecting their common origin (the neural crest). J Periodontol 2005;76: 1044‐1055.
Evaluation of Surgical and Non‐Surgical Periodontal Therapies, and Immunological Status, of Young Down's Syndrome Patients
Authors: Zaldivar‐Chiapa R.M. , Arce‐Mendoza A.Y. , Rosa‐Ramírez M. De La , Caffesse R.G. , Solis‐Soto J.M.
Published: July 2005

Background: Individuals with Down's syndrome (DS) differ in their oral condition compared with the healthy population. Periodontal disease in persons with DS under the age of 30 years is very high. Immune deficiencies are also present. For dental practitioners it is difficult to decide on a particular course of treatment. In this study, patients with DS were selected in order to 1) evaluate the effectiveness of surgical and non‐surgical periodontal therapies and 2) assess their immunological status.

Methods: The population consisted of 14 DS patients (14 to 30 years old). Surgical and non‐surgical periodontal therapies were compared in a split‐mouth design. Clinical measurements of plaque index (PI), gingival index (GI), probing depth (PD), and clinical attachment levels (CAL) were taken at baseline, posttreatment, 6 months, and 1 year. Immunomodulatory activity of neutrophils was analyzed in vitro by chemotaxis (Boyden migration chamber), phagocytic activity, and production of super‐oxide anion (NBT reduction) tests and compared between DS patients and healthy controls.

Results: Both surgical and non‐surgical therapies showed a significant improvement in all the clinical parameters compared to baseline. There were no differences between surgical and nonsurgical therapy in PI or GI. There was a significant PD reduction with the non‐surgical therapy at 1 to 3 mm PD. However in PD >3 mm the surgical therapy, although not statistically significant, showed better results. Neutrophil chemotaxis, phagocytic activity, and production of super‐oxide anion were significantly decreased in the DS patients.

Conclusions: After a year, both surgical and non‐surgical therapies have similar periodontal clinical improvement in DS patients. There is partial impairment of immunological functions in DS individuals which does not seem to affect the clinical response to therapy. J Periodontol 2005;76:1061‐1065.
Human Skin and Gingival Keratinocytes Show Differential Regulation of Matrix Metalloproteinases When Combined With Fibroblasts in 3‐Dimensional Cultures
Authors: Chinnathambi Sathivel , Bickenbach Jackie R.
Published: July 2005

Background: Matrix metalloproteinases (MMP) and their inhibitors are expressed in tissues during interactions between keratinocytes and fibroblasts. Maintaining the balance between MMPs and their inhibitors is critical; failure to do so can lead to severe tissue damage or complete destruction, as seen in periodontal disease. Previously we showed that 3‐dimensional (3‐D) cultures of homotypically‐combined skin and gingival cells mimicked the tissues in protein and lipid production, but heterotypic cultures did not.

Methods: We examined the production and activation of MMPs in these homotypic and heterotypic combinations of skin and gingival keratinocytes and fibroblasts during the critical time that they reformed the tissues. Primary fibroblasts and keratinocytes were isolated from normal human gingiva and skin and grown in 3‐D cultures for up to 42 days. MMP‐1, MMP‐2, and MMP‐9 in the media and inhibition of MMPs from these cultures were analyzed.

Results: These experiments determined that skin fibroblasts grown with skin or gingival keratinocytes secrete increased amounts of MMP‐1 compared to gingival fibroblasts; that the interaction of keratinocytes with fibroblasts decreases the amount of MMP‐2 produced by the fibroblasts in 3‐D cultures; that skin keratinocytes, but not gingival keratinocytes, interact with fibroblasts to upregulate expression of the active form of MMP‐9; and that medium conditioned by gingival 3‐D cultures does not contain an inhibitor of MMP‐9

Conclusion: Varying the type of fibroblast beneath the keratinocytes allowed us to determine that skin and gingival keratinocytes differentially regulate the production and activation of MMP‐9, but not MMP‐2, a finding that could influence the success of tissue grafting after periodontal surgery. J Periodontol 2005;76:1072‐1083.
Analysis of Failed Commercially Pure Titanium Dental Implants: A Scanning Electron Microscopy and Energy‐Dispersive Spectrometer X‐Ray Study
Authors: Shibli Jamil Awad , Marcantonio Elcio , d'Avila Susana , Guastaldi Antonio Carlos , Marcantonio Elcio
Published: July 2005

Background: The failure of osseointegration in oral rehabilitation has gained importance in current literature and in clinical practice. The integration of titanium dental implants in alveolar bone has been partly ascribed to the biocompatibility of the implant surface oxide layer. The aim of this investigation was to analyze the surface topography and composition of failed titanium dental implants in order to determine possible causes of failure.

Methods: Twenty‐one commercially pure titanium (cpTi) implants were retrieved from 16 patients (mean age of 50.33 ± 11.81 years). Fourteen implants were retrieved before loading (early failures), six after loading (late failures), and one because of mandibular canal damage. The failure criterion was lack of osseointegration characterized as dental implant mobility. Two unused implants were used as a control group. All implant surfaces were examined by scanning electron microscopy (SEM) and energy‐dispersive spectrometer x‐ray (EDS) to element analysis. Evaluations were performed on several locations of the same implant.

Results: SEM showed that the surface of all retrieved implants consisted of different degrees of organic residues, appearing mainly as dark stains. The surface topography presented as grooves and ridges along the machined surface similar to control group. Overall, foreign elements such as carbon, oxygen, sodium, calcium, silicon, and aluminum were detected in failed implants. The implants from control group presented no macroscopic contamination and clear signs of titanium.

Conclusion: These preliminary results do not suggest any material‐related cause for implant failures, although different element composition was assessed between failed implants and control implants. J Periodontol 2005;76:1092‐1099.