The ups and downs of gene expression and retroviral DNA integration.
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OBJECTIVE: The aim of this study was to compare the fracture resistance of endodontically treated maxillary central incisors with incomplete crown ferrules after chewing simulation. MATERIAL AND METHODS: Forty caries-free maxillary central incisors were divided into 4 groups (n = 10). Endodontic treatment was performed. Teeth were decoronated 2 mm above the cemento-enamel junction (CEJ). Group I (control) provided a 360 degrees circumferential 2-mm ferrule. In group II, a 2-mm ferrule was present on the palatal aspect (status after occlusal overload), and in group III on the facial aspect (status after traumatic injury). In group IV, the ferrule was interrupted by bi-proximal cavitations (simulating caries treatment). The teeth received glass fiber reinforced posts and composite core restorations. All-ceramic crowns were adhesively cemented. Specimens were simultaneously exposed to thermal cycling and mechanical loading (1.2 million cycles; 6,000 cycles 5 degrees/55 degrees C) and finally statically loaded until failure in a universal testing machine (crosshead speed = 1 mm/min). For statistical analysis, the Kruskal-Wallis test was applied followed by the Mann-Whitney U-test as post hoc testing. RESULTS: The median fracture load values (min./max.) were: group I = 502 (326/561), group II = 658 (280/827), group III = 899 (396/1176), and group IV = 360 (279/646). Analysis revealed statistically significant differences between test groups, except between groups I and IV and groups II and IV. CONCLUSIONS: The fracture resistance of endodontically and post/core restored teeth is dependent on the degree of tooth conservation. An incomplete crown ferrule is associated with greater variation in load capacity and, despite high fracture values, inclines to fracture.
OBJECTIVE: To study caries trends and investigate the possible reasons for changes among 5-year-old Norwegian children in the period 1997-2003. In this cross-sectional analytical time trend study at district, county, and national levels, aggregated data from the Public Dental Services (PDS) and official statistics were used, i.e. number of children and percentage receiving treatment, sale of fluoride tablets, socio-economic background, caries prevalence, and d3mft scores. RESULTS: Caries prevalence increased from 30% in 1997 to just over 40% in 2001, but by 2003 it had dropped to 36%. The corresponding mean number of d3mft were 1.1, 1.6, and 1.4 at national level. Caries prevalence and experience varied considerably between counties and between dental districts throughout the observation period. Multivariate analyses at county level indicated a significant negative association (p < 0.05) between caries prevalence, the sale of fluoride tablets, and net mobility. The impacts of the predictor variables education, income, infant mortality, proportion of immigrants, and the percentage of children treated varied but were rarely significant. CONCLUSIONS: The increasing trend in the prevalence of caries among 5-year-old Norwegian children in the period 1997 to 2001 has reversed. The deterioration in dental health of 5-year-olds after 1997 was associated with a reduction in the sale of fluoride tablets, whereas increased sales of fluoride tablets after 1998 reflect improved caries prevention among preschool children and may explain the improved caries status of these children in 2003.
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The sensory conflict theory provides a useful framework for understanding motion sickness. Few modifications of this model have been proposed since its publication. The weak link in the study of motion sickness has been the failure to delineate the anatomic structures that correspond to the model's components. Effective pharmacotherapy is available for treatment of motion sickness. The choice should be based on the need to provide prophylaxis for or treatment of symptoms and on the side effect profile of the drug.
The establishment of a reliable radioimmunoassay for secretin in plasma enabled studies on the physiology of secretin. It was shown that secretin, i.e. the heptacosapeptide isolated by Jorpes and Mutt, is in fact responsible for the phenomena observed by Starling and Bayliss in 1902 when studying the stimulation of pancreatic bicarbonate secretion in response to duodenal acidification. Secretin is released in amounts considerably lower than anticipated, but these amounts are nevertheless sufficient to drive pancreatic and biliary secretion of bicarbonate. Whereas secretin in the fasting state is the most important stimulus to pancreatic secretion of water and bicarbonate, other hormones and nervous factors are essential for the majority of pancreatic postprandial secretion.
Despite substantial interest in the effects of stress on pregnancy, few instruments are available to measure pregnancy-specific stressors. Moreover, research has typically focused on the distressing, negative aspects of pregnancy. This report examines the reliability and validity of the Pregnancy Experience Scale (PES), a 41-item scale that measures pregnancy-specific daily hassles and uplifts. The PES was administered to two cohorts of low risk women at 24, 30, and 36 weeks (n = 52) or 32 and 38 weeks (n = 137). Women perceived their pregnancies to be significantly more intensely and frequently uplifting than hassling. Internal scale reliability was high (alpha = 0.91 to 0.95). Frequency and intensity scores for hassles and uplifts were stable over time (r's = 0.56 to 0.83) and patterns of convergent and discriminant validity emerged between the PES and existing measures of general affective intensity, daily stressors, depressive symptoms, and anxiety. These results indicate that (1) failure to measure pregnancy-specific stress will underestimate the degree to which pregnant women experience distress and (2) measurement of only the negative aspects of pregnancy will overestimate distress and fail to portray the degree to which women are psychologically elevated by their pregnancies. Measurement of hassles relative to uplifts may provide the most balanced assessment of pregnancy appraisal.
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Standard identification systems usually ensure that biopsy material is correctly associated with a given patient. Sometimes, as when a tumor is unexpectedly found, the provenance (proof of origin) of a tissue sample may be questioned; the tissue may have been mislabelled or contaminated with tissue from another patient. Techniques used to confirm tissue provenance include comparing either tissue markers of gender or ABO blood groups; however, these methods have weak confirmatory power. Recently, the use of DNA-based polymerase chain reaction (PCR) techniques has been reported. Paired, formalin-fixed, paraffin-embedded, 10 microns tissue sections were selected from 17 patients, 8 of whom had carcinoma, either by dividing a biopsy section, using sequential biopsies, or sequential biopsy and autopsy tissue. The resulting 36 samples were coded before analysis. In two additional cases, 1-mm fragments of tumor from one patient were included in the tissue block of benign tissue from another patient, the tumor fragments were identified on hematoxylin-and-eosin-stained sections, separately scraped off the glass slide, and analyzed. Tissue from two clinical cases, one of suspected mislabelling and one with a suspected carry-over of malignant tissue were also investigated. Short tandem repeat sequences (STR) or microsatellites, are 2-5 base pair repeats that vary in their repeat number between individuals. This variation (polymorphism) can be assessed using a PCR. A panel of markers of 3 STRs; ACPP, INT 2, and CYP 19 (on chromosomes 3, 11, and 15, respectively) were used. DNA was isolated from the samples after xylene deparaffinization and proteinase digestion, and was then amplified in a radioactive PCR using primers selected to give a product size ranging from 136-178 bases. Amplified products were electrophoresed on denaturing polyacrylamide gels, dried, and autoradiographed. DNA segments were successfully extracted from all samples but one, which was fixed in Bouin's fluid. By comparing allele sizes from the panel, all tissue pairs (other than the Bouin's pair) were successfully matched, the 1-mm tumor fragments were correctly assigned, and the two clinical problems were solved. STRs are highly informative and robust markers, well suited to PCR of small portions of tissue sections, and are an effective method to confirm the provenance of benign and malignant biopsy and autopsy material.
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Calcium ions function as intracellular second messengers in regulating a plethora of cellular processes from acclimative stress responses to survival and programmed cell death. The generation of specificity in Ca2+ signals is dependent on influx and efflux from the extracellular milieu, cytosol and intracellular organelles. One aspect of plant Ca2+ signalling that is currently attracting a great deal of interest is how 'Ca2+-signatures', specific spatio-temporal changes in cytosolic-free Ca2+, encode the necessary information to bring about this range of physiological responses. Here, current information is reviewed on how Ca2+-signatures are generated in plant cells and how stimulus-specific information can be encoded in the form of Ca2+-signatures.
BACKGROUND: Educational outreach visits, particularly when combined with social marketing, appear to be a promising approach to modifying health professional behaviour, especially prescribing. Results from previous studies have shown a varying effect. OBJECTIVE: The purpose of the study is to examine the effect of academic detailing as a method of implementing a clinical guideline in general practice. METHODS: A cluster randomized, controlled, blinded study was carried out of the effect of an academic detail visit compared with postal distribution of a guideline for prescribing asthma medication. Half the practices in a Danish county with 100 practices were visited once. The outcome measure was routinely collected data from all Danish pharmacies on the sales of asthma medication. Data were collected monthly for 2 years before to 1 year after the intervention. RESULTS: There was no effect on the pattern of prescription of asthma medicines following the visit, neither immediately nor long term. CONCLUSION: We found no effect of academic detailing as a single intervention.
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In an effort to discover novel oligonucleotide modifications for antisense therapeutics, we have prepared oligodeoxyribonucleotides containing more than 200 different modifications and measured their affinities for complementary RNA. These include modifications to the heterocyclic bases, the deoxy-ribose sugar and the phosphodiester linkage. From these results, we have been able to determine structure-activity relationships that correlate hybridization affinity with changes in oligonucleotide structure. Data for oligonucleotides containing modified pyrimidine nucleotides are presented. In general, modifications that resulted in the most stable duplexes contained a heteroatom at the 2'-position of the sugar. Other sugar modifications usually led to diminished hybrid stability. Most backbone modifications that led to improved hybridization restricted backbone mobility and resulted in an A-type sugar pucker for the residue 5'to the modified internucleotide linkage. Among the heterocycles, C-5-substituted pyrimidines stood out as substantially increasing duplex stability.