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Stevens A, Payne N, Akehurst R, Milne R, Gabbay J, Burls A. DEC methods for appraising new drugs. Paper has errors and omissions. BMJ (CLINICAL RESEARCH ED.) 1999; 319:1006-7. [PMID: 10576844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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Chell J, Stevens A, Davis TRC. Work practices and histopathological changes in the tenosynovium and flexor retinaculum in carpal tunnel syndrome in women. ACTA ACUST UNITED AC 1999. [DOI: 10.1302/0301-620x.81b5.0810868] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We studied 58 women of employable age with the carpal tunnel syndrome in order to determine whether the histological appearances of the carpal tunnel, tenosynovium and flexor retinaculum are influenced by work practices. Age, body mass index and the duration of symptoms did not correlate with the extent of oedema or fibrosis within the tenosynovium. The incidence of abnormality on histological examination of the tenosynovium was the same in employed and unemployed patients (p = 1.0), and was not influenced by the level of repetition (p = 0.89) or force (p = 0.29) of work. Myxoid degeneration within the flexor retinaculum was, however, more common in women undertaking ‘high-force’ work. Apart from this finding, the results suggest that work practices do not affect tenosynovial thickening, fibrosis or oedema in patients with carpal tunnel syndrome.
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Chell J, Stevens A, Davis TR. Work practices and histopathological changes in the tenosynovium and flexor retinaculum in carpal tunnel syndrome in women. THE JOURNAL OF BONE AND JOINT SURGERY. BRITISH VOLUME 1999; 81:868-70. [PMID: 10530852 DOI: 10.1302/0301-620x.81b5.9453] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We studied 58 women of employable age with the carpal tunnel syndrome in order to determine whether the histological appearances of the carpal tunnel, tenosynovium and flexor retinaculum are influenced by work practices. Age, body mass index and the duration of symptoms did not correlate with the extent of oedema or fibrosis within the tenosynovium. The incidence of abnormality on histological examination of the tenosynovium was the same in employed and unemployed patients (p = 1.0), and was not influenced by the level of repetition (p = 0.89) or force (p = 0.29) of work. Myxoid degeneration within the flexor retinaculum was, however, more common in women undertaking 'high-force' work. Apart from this finding, the results suggest that work practices do not affect tenosynovial thickening, fibrosis or oedema in patients with carpal tunnel syndrome.
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Silkoff PE, Stevens A, Pak J, Bucher-Bartelson B, Martin RJ. A method for the standardized offline collection of exhaled nitric oxide. Chest 1999; 116:754-9. [PMID: 10492283 DOI: 10.1378/chest.116.3.754] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
STUDY OBJECTIVES Exhaled nitric oxide (ENO) is a noninvasive marker of airway inflammation. The purpose of this study was to compare a standardized offline ENO measurement apparatus with a validated on-line method. DESIGN Asthmatic volunteers (n = 21) had ENO measured by the two following methods: (1) inhalation to total lung capacity (TLC) followed by exhalation at a constant flow (45 mL/s) against a high resistance, while monitoring nitric oxide (NO) and pressure on-line; and (2) inhalation to TLC and exhalation into mylar balloons via an apparatus that included the same resistance and flow rate as used in the on-line method. We also examined NO stability in mylar balloons over 48 h. MEASUREMENTS AND RESULTS ENO values (given as geometric mean in parts per billion [ppb]; 95% confidence intervals) differed between the on-line method (69.6; 42.6 to 113.8) and the offline method (49.5; 30.9 to 79.3), indicating that the offline method gave lower ENO measures than the on-line method (p < 0.001). Furthermore, this difference between measures increased with increasing mean values. The intraclass correlation coefficient (0.931), however, showed excellent correlation between the on-line and offline methods. Within-subject repeatability, as assessed by the coefficient of repeatability (CR), was good for both the on-line and offline methods (CR, 1.09 and 1.17, respectively). Geometric mean NO concentrations (95% confidence limits) in mylar balloons containing exhalate increased from a baseline of 55.8 ppb (36.9, 84.4) to 64.5 ppb (45.6, 91.1) and 69.5 ppb (51.4, 94.0) at 24 h and 48 h, respectively. CONCLUSIONS The offline method gave reproducible ENO values that were consistently smaller than, but showed good correlation with, values obtained with on-line ENO collection. This method is suitable for offline collection, but the measured values are not interchangeable with those obtained by on-line measurement.
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Stevens A, Mattes R, Günther W, Müller N, Trapp W. First-episode schizophrenics show normal duration and topography of quasistationary EEG segments as compared to controls, during rest as well as during active tasks. Psychiatry Res 1999; 91:111-20. [PMID: 10515466 DOI: 10.1016/s0925-4927(99)00022-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In patients suffering from chronic schizophrenia, both altered temporospatial structure of the EEG and impaired activation during cognitive tasks have repeatedly been demonstrated. The present study evaluates whether similar abnormalities are present in drug-naive first-episode schizophrenics. The EEGs of 32 schizophrenic patients and of 52 healthy controls were recorded during a simple and a complicated motor task, a simple and a complicated auditory stimulus, and during resting periods between the tasks. The temporospatial characteristics were evaluated by adaptive segmentation of EEG, which decomposes an EEG into temporal segments of quasistationary activity. No differences in the temporal and topographic aspects of the EEGs were found between the first-episode schizophrenic patients and the controls, neither during the resting EEGs nor during active tasks. Moreover, the dynamic course of the EEGs, defined as the alternation between task-related changes of temporospatial patterns and the reappearance of resting patterns, was identical in patients and controls. The present findings suggest that while abnormal EEG power spectra seem a consistent finding in treated as well as in never-treated schizophrenics, altered temporospatial patterns and reduced task-related EEG changes are inconsistent signs.
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Stevens A. Face to face: a conversation with the Registrar of the Faculty of General Dental Practitioners (UK). Interview by Ted Renson. PRIMARY DENTAL CARE : JOURNAL OF THE FACULTY OF GENERAL DENTAL PRACTITIONERS (UK) 1999; 6:117-8. [PMID: 11819875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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Stevens A, Price JS. Behavioural ecological approach to depression. Br J Psychiatry 1999; 175:87. [PMID: 10621773 DOI: 10.1192/bjp.175.1.87a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Dolinar J, Ollayos CW, Tellado M, Ali I, Stevens A, Paquette C, Brodbelt S. The false-negative fraction: a statistical method to measure the efficacy of cervical smear screening laboratories. Mil Med 1999; 164:410-1. [PMID: 10377709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
The false-negative fraction (FNF) is emerging as a statistical parameter that may be used to evaluate the efficacy of Papanicolaou smear screening laboratories. Our objectives for this paper are to acquaint non-laboratorians with this important measurement and to measure the FNF of the Air Force Cyto-center (AFCC) at the Armed Forces Institute of Pathology in Washington, DC. The FNF is defined as estimated false negatives divided by (true positives plus estimated false negatives). Most often, the number generated is multiplied by 100 and expressed as a percent. We have determined the FNF of the AFCC to be 3.7%. This value compares favorably with most others reported in the medical literature.
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Gumbiner J, Arriaga T, Stevens A. Comparison of MMPI-A, Marks and Briggs, and MMPI-2 norms for juvenile delinquents. Psychol Rep 1999; 84:761-6. [PMID: 10408198 DOI: 10.2466/pr0.1999.84.3.761] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A study was conducted to compare scores of juvenile delinquents on the new MMPI-A to previous research and to compare 3 sets of norms for adolescents: the MMPI-A, the Marks-Briggs adolescent norms, and the MMPI-2 adult norms. Subjects, 11 boys and 11 girls, were hospitalized adolescents, aged 14 to 17 years, with a history of conduct problems. Analysis of MMPI-A scale scores for boys indicated elevated T-score means on scales F (64), Hs (64), Pd (65), Pa (68), Pt (68), Sc (70), and Ma (66). Mean T scores for girls on the MMPI-A were elevated on scales of F (62), Pd (64), and Sc (62). The findings that the mean T score for scales Pd, Sc, and Ma are elevated for this population is consistent with previous research on juvenile delinquents. In general, the MMPI-A scale elevations were lowest, followed by the Marks-Briggs norms. The MMPI-2 T-score means were the most elevated. One of the limitations of the present investigation is an extremely small sample. Until further research is conducted on larger samples, clinicians concerned about the different norms are encouraged to plot MMPI-A scores on both adolescent and adult norms. It is also recommended that the MMPI-A be included as part of an assessment battery with other objective tests, clinical observation, and patient report.
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Battye R, Stevens A, Jacobs JR. Axon repulsion from the midline of the Drosophila CNS requires slit function. Development 1999; 126:2475-81. [PMID: 10226006 DOI: 10.1242/dev.126.11.2475] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Guidance of axons towards or away from the midline of the central nervous system during Drosophila embryogenesis reflects a balance of attractive and repulsive cues originating from the midline. Here we demonstrate that Slit, a protein secreted by the midline glial cells provides a repulsive cue for the growth cones of axons and muscle cells. Embryos lacking slit function show a medial collapse of lateral axon tracts and ectopic midline crossing of ventral muscles. Transgene expression of slit in the midline restores axon patterning. Ectopic expression of slit inhibits formation of axon tracts at locations of high Slit production and misdirects axon tracts towards the midline. slit interacts genetically with roundabout, which encodes a putative receptor for growth cone repulsion.
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Stevens A, Doidge N, Goldbloom D, Voore P, Farewell J. Pilot study of televideo psychiatric assessments in an underserviced community. Am J Psychiatry 1999; 156:783-5. [PMID: 10327917 DOI: 10.1176/ajp.156.5.783] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The goal of this study was to evaluate patient and physician acceptance of televideo interviews for general psychiatric assessments. METHOD DSM-III-R diagnoses for axes I and II were made for 40 patients by using the Structured Clinical Interview for DSM-III-R. The patients were then randomly assigned to face-to-face or televideo interviews for general psychiatric assessments conducted by psychiatrists. After each interview the patient and psychiatrist completed measures evaluating perceived rapport and level of satisfaction with the interview. RESULTS The patients gave high ratings to both satisfaction and ability to develop rapport for both the televideo and face-to-face interviews. The psychiatrists expressed significantly less satisfaction with the televideo interviews, but their actual ratings were positive. CONCLUSIONS Despite geographic distance, televideo interviews allow a sense of connection between patient and psychiatrist. Lower-cost technology may increase the use of televideo to extend psychiatric service to geographically isolated communities.
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Pope JE, Bellamy N, Stevens A. The lack of associations between rheumatoid arthritis and both nulliparity and infertility. Semin Arthritis Rheum 1999; 28:342-50. [PMID: 10342392 DOI: 10.1016/s0049-0172(99)80019-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVES Rheumatoid arthritis (RA) is an autoimmune disease that occurs more commonly in women and frequently onsets in women of childbearing age. Pregnancy often causes disease remission, with a subsequent flare postpartum. Nulliparity may be a risk factor for RA, but the literature does not consistently report this finding. There may be a production of antibodies in women with RA that could lead to infertility, and subsequent nulliparity, but this has not been proved. We wanted to determine whether there was a relationship between nulliparity, infertility, oral contraceptive use, and adverse pregnancy outcome in women with newly diagnosed RA. METHODS Through a case control study, using a mailed questionnaire, we compared the fertility and pregnancy outcome histories of 34 women between the ages of 19 and 44 years with recent-onset RA with 68 healthy controls matched for age and marital status. The response rate was 97%. A review of the literature also was performed to study the associations between RA and infertility and nulliparity, using Medline searching key references. RESULTS We found no association between infertility and the onset of RA. Seventy-one percent of women with RA and 68% of controls had been pregnant. There was a trend toward increased nulliparity in these patients, but the result was not statistically significant (odds ratio [OR], 1.4; P<.6). There were no differences in the number of children (2.6 v. 2.7; P<.6) and parity outcomes in the two groups. Age at first pregnancy was younger in the women with RA (22.6 v. 25.5 years; P<.008), but the education level was higher in the controls (P<.0001), which may explain these differences. Oral contraceptive use was lower in the RA women, but more RA women had long-term use (greater than or equal to 5 years), and neither result was statistically significant. Literature review shows that at best, there are weak negative associations between current estrogen use and RA, and no association with nulliparity and infertility. CONCLUSIONS It appears that infertility, the number of pregnancies, and pregnancy outcome are not strongly associated with the risk of developing RA in women of childbearing age. However, in this study there may have been selection biases in the women with RA and the controls that differentially could have affected their reproductive outcomes. Thus, a true association could have been missed. Most other published studies find no association between nulliparity and RA.
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Robert G, Gabbay J, Stevens A. Which are the best information sources for identifying emerging health care technologies? An international Delphi survey. Int J Technol Assess Health Care 1999; 14:636-43. [PMID: 9885453 DOI: 10.1017/s0266462300011946] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The purpose of this survey was to assess potential information sources for identifying new health care technologies. A three-round Delphi study was conducted, involving 38 selected experts who suggested and assessed potential sources by applying agreed criteria. Twenty-six potential information sources were considered. Timeliness, time efficiency, and sensitivity were important criteria in determining which were the most important sources. The eight recommended sources were: pharmaceutical journals, pharmaceutical and biotechnology companies, specialist medical journals, key medical journals, medical engineering companies, private health care providers, newsletters and bulletins from other health technology assessment agencies, and groups of expert health professionals. There is a need to use a combination of sources because the most useful sources will vary according to the type of technology under consideration.
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Stevens A, Packer C, Robert G. Early warning of new health care technologies in the United Kingdom. Int J Technol Assess Health Care 1999; 14:680-6. [PMID: 9885458 DOI: 10.1017/s0266462300011995] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this paper we describe the present range of organizations that have a role in the early warning of new and emerging health care technologies in the United Kingdom. We discuss in more detail the processes and prioritization criteria used by the U.K. horizon-scanning project for the NHS Health Technology Assessment Programme, and the principal methods of technology identification for the horizon-scanning project are outlined. The United Kingdom plans to develop an integrated system for the identification of technologies for commercial planning, health service research prioritization, financial planning, and provision of information to policy makers, purchasers, and providers of health care.
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Abstract
mRNA decapping is a common step shared between two important mRNA decay pathways in yeast, Saccharomyces cerevisiae. To investigate how mRNAs are decapped, we have developed an assay that can be easily used to measure the decapping activity. This assay has been used to isolate yeast strains with altered decapping activities. The results demonstrated that decreased decapping activity in vitro corresponds well with the decapping-deficient phenotype in vivo. This assay has been applied to the purified yeast decapping enzyme Dcp1 protein as well as crude yeast extracts and Xenopus oocyte extracts.
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Doktycz MJ, Larimer FW, Pastrnak M, Stevens A. Comparative analyses of the secondary structures of synthetic and intracellular yeast MFA2 mRNAs. Proc Natl Acad Sci U S A 1998; 95:14614-21. [PMID: 9843938 PMCID: PMC24498 DOI: 10.1073/pnas.95.25.14614] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The overall folded (global) structure of mRNA may be critical to translation and turnover control mechanisms, but it has received little experimental attention. Presented here is a comparative analysis of the basic features of the global secondary structure of a synthetic mRNA and the same intracellular eukaryotic mRNA by dimethyl sulfate (DMS) structure probing. Synthetic MFA2 mRNA of Saccharomyces cerevisiae first was examined by using both enzymes and chemical reagents to determine single-stranded and hybridized regions; RNAs with and without a poly(A) tail were compared. A folding pattern was obtained with the aid of the MFOLD program package that identified the model that best satisfied the probing data. A long-range structural interaction involving the 5' and 3' untranslated regions and causing a juxtaposition of the ends of the RNA, was examined further by a useful technique involving oligo(dT)-cellulose chromatography and antisense oligonucleotides. DMS chemical probing of A and C nucleotides of intracellular MFA2 mRNA was then done. The modification data support a very similar intracellular structure. When low reactivity of A and C residues is found in the synthetic RNA, approximately 70% of the same sites are relatively more resistant to DMS modification in vivo. A slightly higher sensitivity to DMS is found in vivo for some of the A and C nucleotides predicted to be hybridized from the synthetic structural model. With this small mRNA, the translation process and mRNA-binding proteins do not block DMS modifications, and all A and C nucleotides are modified the same or more strongly than with the synthetic RNA.
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Stevens A, Kircher T. Cognitive decline unlike normal aging is associated with alterations of EEG temporo-spatial characteristics. Eur Arch Psychiatry Clin Neurosci 1998; 248:259-66. [PMID: 9840373 DOI: 10.1007/s004060050047] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The diagnosis of beginning dementia is based mainly on neuropsychological testing. Several measures of EEG spectral composition, coherence and complexity (correlation dimension) have been shown to correspond to cognitive function. Only a few studies have evaluated EEG changes in normal aging, and no quantitative study has addressed changes in EEG during cognitive tasks in demented elderly. In this study the quantitative descriptors of EEGs from 31 demented or cognitively impaired elderly persons, 30 healthy elderly (mean age 69 years) and 35 young controls (mean age 31 years) were compared. The EEGs were recorded during two resting conditions (eyes closed and eyes opened) and two tasks (mental arithmetics and a lexical decision). The goal of the study was to evaluate which temporal and spatial EEG descriptors change with cognitive decline and with normal aging, respectively. Cognitive categories (unimpaired, impaired, demented) were based on Structured Interview for the Diagnosis of Dementia of Alzheimer Type (SIDAM) scores. The EEGs were analysed using adaptive segmentation of continuous EEG, which quantifies the succession of distinct stable topographic voltage patterns (EEG microstates). The main findings were a significant increase in the number of ultra-short EEG microstates and, independently, a reduction in the average duration of EEG microstates in the cognitively impaired and demented patients. In addition, cognitive impairment was associated with a reduction or loss of EEG reactivity normally observed when the resting states with closed and with opened eyes are compared. No alterations in temporal or spatial EEG descriptors were found in normal aging. Cognitive tasks did not add to information already obtained during the resting states. The reduction in EEG microstate duration correlated with loss of cognitive function. Temporo-spatial analysis of EEG therefore is a useful indicator of cortical dysfunction in dementia, correlating with the degree of cognitive impairment. Normal aging seems not to be accompanied by changes in temporo-spatial EEG patterns. The data suggest that fragmentation of the electrophysiological processes underlies cognitive dysfunction in Alzheimer's disease.
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Stevens A. The advice game. Layoffs, a need for change push execs into consulting. MODERN HEALTHCARE 1998; 28:50, 52. [PMID: 10187707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Wiedemann G, Stevens A, Pauli P, Dengler W. Decreased duration and altered topography of electroencephalographic microstates in patients with panic disorder. Psychiatry Res 1998; 84:37-48. [PMID: 9870416 DOI: 10.1016/s0925-4927(98)00044-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The topography and temporal sequence of scalp electrical fields were analyzed by adaptive segmentation of the continuous electroencephalogram (EEG) in 27 patients with panic disorder and 28 control subjects during rest phases and during the viewing of a neutral (mushroom) or an emotionally relevant (casualty) picture. The results indicate decreased duration of brain microstates in panic patients during all conditions. Comparison of the resting phases with the viewing conditions revealed a significant acceleration of EEG microstates in both the patients and the control subjects. Patients and control subjects differed in the topography of the fields during rest: control subjects showed a left-anterior/right-posterior orientation, while panic patients showed a predominantly right-anterior/left-posterior orientation. Neither group displayed any topographic changes when viewing the mushroom picture. However, when viewing the anxiety-specific casualty picture, panic patients shifted fields in a different way than did control subjects. Centroid topography does not permit clear localization of the cortical generators. It is concluded that panic patients show a generally increased cortical activation compared with healthy control subjects, and activate different neuronal arrays when viewing an anxiety-specific stimulus.
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Van den Enden E, Stevens A, Van Gompel A. Treatment of cutaneous larva migrans. N Engl J Med 1998; 339:1246-7. [PMID: 9786758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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Stevens A. Endonucleolytic cleavage of RNA at 5' endogenous stem structures by human flap endonuclease 1. Biochem Biophys Res Commun 1998; 251:501-8. [PMID: 9792803 DOI: 10.1006/bbrc.1998.9499] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Structure-specific nucleases called 5' flap endonucleases cleave unannealed 5' arms of template-primer DNA model substrates at the start of the duplex and are involved in Okazaki fragment processing during DNA synthesis. To determine the possible use of the enzymes in RNA structure analysis, the cleavage of synthetic and native RNAs was examined using flap endonuclease 1 (Fen1) of HeLa cells. RNAs are cleaved at about 20% of the rate of DNA model substrates, and most of the cleavage sites are within 200 nucleotides of the 5' end. Hydrolysis of MFA2 mRNA of yeast shows that the cleavages are at the start of five possible stem structures of a folded secondary structure predicted on the basis of both chemical and enzymatic structure probing. 16S ribosomal RNA of Escherichia coli is cleaved at several 5' stem structures of its phylogenetically predicted folded structure. This type of RNA cleavage specificity may be very useful in secondary structure analysis in the future and also may be used by cells for specific 5' end-geared RNA cleavages.
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Pope JE, Stevens A, Howson W, Bell DA. The development of rheumatoid arthritis after recombinant hepatitis B vaccination. J Rheumatol 1998; 25:1687-93. [PMID: 9733447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVE Hepatitis B vaccination has been associated with reactive arthritis and rarely rheumatoid arthritis (RA). We defined the clinical, serologic, and immunogenetic background of patients developing RA, soon after recombinant hepatitis B vaccination. METHODS The clinical, serologic, and HLA antigens of a cluster of firefighters who developed arthritis after prophylactic recombinant hepatitis B vaccination (5 subjects), as well as a second group of sporadic cases of arthritis (6 patients) after hepatitis B vaccination are described. RESULTS Ten of 11 patients fulfilled revised American College of Rheumatology criteria for RA. All cases had persistent arthritis for more than 6 months; at 48 months followup 2 cases no longer had inflammatory arthritis. Nine patients required disease modifying antirheumatic drugs. Five subjects were HLA-DR4 positive. HLA class II genes expressing the RA shared motif were identified in 9/11 patients genotyped for HLA-DRbeta1 and DQbeta1 alleles (0401, 0101, or 0404). All the firefighters shared the HLA-DRbeta1 allele 0301 and the DQbeta1 allele 0201, with which it is in linkage disequilibrium. CONCLUSION These polymorphic residues in the binding site of the MHC class II molecules of the affected patients appear capable of binding some peptide sequences of the recombinant vaccine peptides they received and may be responsible for hepatitis B vaccine triggering development of RA in these cases. Recombinant hepatitis B vaccine may trigger the development of RA in MHC class II genetically susceptible individuals.
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De Laat A, Meuleman H, Stevens A, Verbeke G. Correlation between cervical spine and temporomandibular disorders. Clin Oral Investig 1998; 2:54-7. [PMID: 15490776 DOI: 10.1007/s007840050045] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Neuroanatomical interconnections and neurophysiological relationships between the orofacial area and the cervical spine have been documented earlier. The present single-blind study was aimed at screening possible correlations between clinical signs of temporomandibular disorders (TMD) and cervical spine disorders. Thirty-one consecutive patients with symptoms of TMD and 30 controls underwent a standardised clinical examination of the masticatory system, evaluating range of motion of the mandible, temporomandibular joint (TMJ) function and pain of the TMJ and masticatory muscles. Afterwards subjects were referred for clinical examination of the cervical spine, evaluating segmental limitations, tender points upon palpation of the muscles, hyperalgesia and hypermobility. The results indicated that segmental limitations (especially at the C0-C3 levels) and tender points (especially in the m. sternocleidomastoideus and m. trapezius) are significantly more present in patients than in controls. Hyperalgesia was present only in the patient group (12-16%).
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Stevens A. The contribution of glycation to cataract formation in diabetes. JOURNAL OF THE AMERICAN OPTOMETRIC ASSOCIATION 1998; 69:519-30. [PMID: 9747048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Despite extensive research, the mechanisms responsible for Type II diabetic cataract formation are still unknown. Recent data have favored non-enzymatic glycation. However, the pathways by which hyperglycemia leads to cataract are still unknown. Two possible routes were explored; modification of the lens proteins leading to Advanced Glycation Endproduct (AGE) formation and modification of the ATPase pumps leading to osmotic stress. METHODS The extent of AGE formation was monitored in fetal bovine eyes using non-tryptophan fluorescence. The amount of carbohydrate bound the proteins was measured after reduction with radiolabelled sodium borohydride. Secondary structure estimations were performed by analysis of data obtained using circular dichroism. The effect of glycation on the Na, K-ATPase ion pumps was investigated by comparing the uptake of radioactive 86Rb in the presence of high concentrations of glucose and fructose. RESULTS These studies were aimed at determining which of these mechanisms is the more likely route for cataract formation. The first mechanism was examined using two approaches. Firstly, by investigating the effects of increased glucose on the secondary and tertiary structure of lens proteins. Detailed analysis of the structures of the lens proteins in the presence of 200 mM glucose revealed that only alpha-crystallin was slightly affected. More important, however, this change did not lead to any significant aggregation. The second approach involved comparing the mechanism of action and possible benefits of anti-glycating agents. CONCLUSION It is concluded that Type II diabetes cataracts are unlikely to arise as a result of AGE formation, but rather they form because of disruption of the cells, as a result of osmotic stress, brought about by glycation of the ion pumps.
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Nelson RD, Stricklett P, Gustafson C, Stevens A, Ausiello D, Brown D, Kohan DE. Expression of an AQP2 Cre recombinase transgene in kidney and male reproductive system of transgenic mice. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:C216-26. [PMID: 9688853 DOI: 10.1152/ajpcell.1998.275.1.c216] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A transgenic mouse approach was used to examine the mechanism of principal cell-specific expression of aquaporin-2 (AQP2) within the renal collecting duct. RT-PCR and immunocytochemistry revealed that murine AQP2 was expressed in principal cells in the renal collecting duct, epithelial cells of the vas deferens, and seminiferous tubules within testis. The vas deferens expression was confirmed in rats. RT-PCR and immunocytochemistry showed that 14 kb of the human 5'-flanking region confers specific expression of a nucleus-targeted and epitope-tagged Cre recombinase in the principal cells within the renal collecting duct, in the epithelial cells of the vas deferens, and within the testis of transgenic mice. These results suggest that cell-specific expression of AQP2 is mediated at the transcriptional level and that 14 kb of the human AQP2 5'-flanking region contain cis elements that are sufficient for cell-specific expression of AQP2. Finally, renal principal cell expression of Cre recombinase is the first step in achieving cell-specific gene knockouts, thereby allowing focused examination of gene function in this cell type.
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