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Duncan PW, Weiner DK, Chandler J, Studenski S. Functional reach: a new clinical measure of balance. JOURNAL OF GERONTOLOGY 1990; 45:M192-7. [PMID: 2229941 DOI: 10.1093/geronj/45.6.m192] [Citation(s) in RCA: 1611] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A new clinically accessible measure of balance, functional reach (FR), is the difference between arm's length and maximal forward reach, using a fixed base of support. The purposes of this study were to (a) establish FR as a measure of the margin of stability versus the laboratory measure, center of pressure excursion (COPE); (b) test reliability and precision, and (c) determine factors that influence FR, including age and anthropometrics. We evaluated FR in 128 volunteers (age 21-87 years). FR was determined with a precise electronic device and a simple clinical apparatus (yardstick). FR correlates with COPE (Pearson r = .71) and is precise (coefficient of variation = 2.5%) and stable (intraclass correlation coefficient across days = .81). Age and height influence FR. FR is portable, inexpensive, reliable, precise, and a reasonable clinical approximator of the margin of stability. FR may be useful for detecting balance impairment, change in balance performance over time, and in the design of modified environments for impaired older persons.
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Chandler JR, Langenbrunner DJ, Stevens ER. The pathogenesis of orbital complications in acute sinusitis. Laryngoscope 1970; 80:1414-28. [PMID: 5470225 DOI: 10.1288/00005537-197009000-00007] [Citation(s) in RCA: 573] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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573 |
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Duncan PW, Studenski S, Chandler J, Prescott B. Functional reach: predictive validity in a sample of elderly male veterans. JOURNAL OF GERONTOLOGY 1992; 47:M93-8. [PMID: 1573190 DOI: 10.1093/geronj/47.3.m93] [Citation(s) in RCA: 436] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A new measure of balance, functional reach, has been recently developed. Functional reach is the maximal distance one can reach forward beyond arm's length while maintaining a fixed base of support in the standing position. Reliability, criterion, and concurrent construct validity of functional reach have been established. The purpose of this study was to assess the predictive validity of functional reach in identifying elderly subjects at risk for recurrent falls. Two hundred and seventeen elderly, community-dwelling male veterans (aged 70-104) underwent baseline screening and were followed for 6 months to monitor falls. Subjects with two or more falls during the 6-month follow-up were classified as recurrent fallers. Logistic regression reveals that if individuals were unable to reach, the adjusted odds ratio (OR) of having two falls was 8.07 (2.8-23.71); if their reach was less than or equal to 6 inches the OR was 4.02 (1.84-8.77); and if reach was greater than 6 inches but less than 10 inches the OR was 2.00 (1.35-2.98). The association between functional reach and recurrent falls was not confounded by age, depression, or cognition. We conclude that functional reach is a simple and easy-to-use clinical measure that has predictive validity in identifying recurrent falls.
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436 |
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Lips P, Hosking D, Lippuner K, Norquist JM, Wehren L, Maalouf G, Ragi-Eis S, Chandler J. The prevalence of vitamin D inadequacy amongst women with osteoporosis: an international epidemiological investigation. J Intern Med 2006; 260:245-54. [PMID: 16918822 DOI: 10.1111/j.1365-2796.2006.01685.x] [Citation(s) in RCA: 351] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
INTRODUCTION Vitamin D is essential for calcium metabolism as well as for fracture prevention, and a recent review suggested that the optimal serum 25(OH)D lies in the region of 50-80 nmol L-1 (20-32 ng mL-1). A high prevalence of inadequacy has been reported in many studies but the prevalence of inadequacy amongst women with osteoporosis in different regions of the world has not been well characterized. SETTING AND SUBJECTS A multinational study of 18 countries at various latitudes (range 64N-38S) was conducted in 2004 and 2005 to determine the average levels of serum 25(OH)D and the prevalence of vitamin D inadequacy. A total of 2606 postmenopausal women with osteoporosis (low bone mineral density, history of fragility fracture) seeking routine medical care were enrolled and serum 25(OH)D levels were measured at a single laboratory visit. RESULTS Mean serum 25(OH)D level was 26.8 ng mL-1 (SE 0.3) and ranged from 7 to 243 ng mL-1. Regional mean values were highest in Latin America (29.6 ng mL-1, SE 0.6) and lowest in the Middle East (20.4 ng mL-1, SE 0.5). Overall, 64% of women had serum levels<30 ng mL-1. Serum parathyroid hormone reached a nadir at serum 25(OH)D levels>35 ng mL-1. In nonequatorial countries, women recruited during the winter months had somewhat lower serum 25(OH)D levels than those recruited during the summer months in some, but not all, countries. CONCLUSIONS Low levels of serum 25(OH)D are common amongst women with osteoporosis. The results underscore the value of assuring vitamin D adequacy in these women.
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Multicenter Study |
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Abstract
OBJECTIVE To establish the concurrent validity of our new balance instrument, functional reach (FR = maximal safe standing forward reach), as a marker of physical frailty compared with other clinical measures of physical performance. DESIGN, SETTING AND PARTICIPANTS 45 community-dwelling persons age 66-104 were evaluated at one point in time using (1) FR (yardstick method), (2) Physical and Instrumental Activities of Daily Living (PADL, IADL), (3) Life Space, a 3-point measure of social mobility, (4) 10-item hierarchical mobility skills protocol, (5) 10-foot walking speed, (6) one-footed standing, and (7) tandem walking. Data analysis employed Spearman correlations. Partial r's were also calculated after controlling for age. RESULTS The FR performance range was broad (4.3-16.5 inches, mean 10.9, SD 3.1). Except for PADL, the association of FR with the other physical performance measures was strong, with r's ranging from 0.64-0.71; the association of FR with PADL was 0.48. After controlling for age in the regression analysis, partial r's ranged from 0.52-0.63. The association of FR with age was -0.50. CONCLUSIONS Based on cross-sectional data, FR is a practical instrument that correlates with physical frailty even more than with age.
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Borner R, Kampmann G, Chandler J, Gleissner R, Wisman E, Apel K, Melzer S. A MADS domain gene involved in the transition to flowering in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2000; 24:591-9. [PMID: 11123798 DOI: 10.1046/j.1365-313x.2000.00906.x] [Citation(s) in RCA: 211] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Flowering time in many plants is triggered by environmental factors that lead to uniform flowering in plant populations, ensuring higher reproductive success. So far, several genes have been identified that are involved in flowering time control. AGL20 (AGAMOUS LIKE 20) is a MADS domain gene from Arabidopsis that is activated in shoot apical meristems during the transition to flowering. By transposon tagging we have identified late flowering agl20 mutants, showing that AGL20 is involved in flowering time control. In previously described late flowering mutants of the long-day and constitutive pathways of floral induction the expression of AGL20 is down-regulated, demonstrating that AGL20 acts downstream to the mutated genes. Moreover, we can show that AGL20 is also regulated by the gibberellin (GA) pathway, indicating that AGL20 integrates signals of different pathways of floral induction and might be a central component for the induction of flowering. In addition, the constitutive expression of AGL20 in Arabidopsis is sufficient for photoperiod independent flowering and the over-expression of the orthologous gene from mustard, MADSA, in the classical short-day tobacco Maryland Mammoth bypasses the strict photoperiodic control of flowering.
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Studenski S, Duncan PW, Chandler J, Samsa G, Prescott B, Hogue C, Bearon LB. Predicting falls: the role of mobility and nonphysical factors. J Am Geriatr Soc 1994; 42:297-302. [PMID: 8120315 DOI: 10.1111/j.1532-5415.1994.tb01755.x] [Citation(s) in RCA: 169] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE Our purpose was to test a four-domain predictive model of recurrent falls developed for this study. In this model, limited mobility is considered a necessary but not sufficient element in risk of recurrent falls. Three other domains, attitudinal, social, and environmental, are proposed to influence fall risk only in persons with impaired mobility. DESIGN Prospective cohort study. SETTING Veterans Affairs Ambulatory Care Service serving rural and urban central North Carolina. SUBJECTS Male Veterans aged 70 or older (n = 306) were monitored prospectively for falls. At baseline, 159 screened as high-risk mobility status and 147 as low-risk mobility status. MEASUREMENTS The primary outcome was recurrent falls. The mobility screen used for risk assignment defined immobile as unable to sit without support for 60 seconds, mobile and stable as meeting criteria for normal ambulation and stair climbing, and mobile but unstable as those who met neither of the above criteria. The high-risk subjects were further assessed in their homes for mobility in more detail, attitude toward risk, social supports, and environmental status. Other data included demographics, functional status, diagnoses, and medications. RESULTS Recurrent falls occurred in 37 (23.3%) high-risk subjects and seven (4.8%) low-risk subjects (relative risk = 4.8, confidence interval 2.5 to 9.6, P < 0.001). Within the high-risk group, the probability of recurrent falls was significantly affected by degree of impaired mobility (P < 0.001), attitude toward risk (P = 0.005), and environment score (P = 0.03). CONCLUSIONS A simple mobility screen can identify elders at increased risk for recurrent falls. Risk within this group is further modified by risk-taking behavior and environment.
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Kristich CJ, Chandler JR, Dunny GM. Development of a host-genotype-independent counterselectable marker and a high-frequency conjugative delivery system and their use in genetic analysis of Enterococcus faecalis. Plasmid 2006; 57:131-44. [PMID: 16996131 PMCID: PMC1852458 DOI: 10.1016/j.plasmid.2006.08.003] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Revised: 06/09/2006] [Accepted: 08/06/2006] [Indexed: 11/16/2022]
Abstract
Enterococcus faecalis is a gram-positive commensal bacterium of the gastrointestinal tract. E. faecalis is also an opportunistic pathogen that frequently exhibits resistance to available antibiotics. Despite the clinical significance of the enterococci, genetic analysis has been restricted by limitations inherent in the available genetic tools. To facilitate genetic manipulation of E. faecalis, we developed a conjugative delivery system for high-frequency introduction of cloned DNA into target strains of E. faecalis and a host-genotype-independent counterselectable marker for use in markerless genetic exchange. We used these tools to construct a collection of E. faecalis mutant strains carrying defined mutations in several genes, including ccfA, eep, gelE, sprE, and an alternative sigma factor (sigH). Furthermore, we combined these mutations in various permutations to create double mutants, triple mutants, and a quadruple mutant of E. faecalis that enabled tests of epistasis to be conducted on the pheromone biosynthesis pathway. Analysis of cCF10 pheromone production by the mutants revealed that both the ccfA2 and delta eep10 mutations are epistatic to mutations in gelE/sprE. To our knowledge, this represents the first example of epistasis analysis applied to a chromosomally encoded biosynthetic pathway in enterococci. Thus, the advanced tools for genetic manipulation of E. faecalis reported here enable efficient and sophisticated genetic analysis of these important pathogens.
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Research Support, N.I.H., Extramural |
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Machtei EE, Hausmann E, Dunford R, Grossi S, Ho A, Davis G, Chandler J, Zambon J, Genco RJ. Longitudinal study of predictive factors for periodontal disease and tooth loss. J Clin Periodontol 1999; 26:374-80. [PMID: 10382577 DOI: 10.1034/j.1600-051x.1999.260607.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Longitudinal assessment of risk factors for periodontal disease is necessary to provide evidence that a putative risk factor or risk indicator is a true risk factor. The purpose of the present study was to explore longitudinally a variety of markers as possible periodontal risk factors in subjects with little or no periodontal disease at baseline. 415 subjects with mild or little periodontal disease were examined: medical and dental history; socioeconomic profile, clinical measurements, microbial samples and radiographic assessment of bone height were performed at baseline, and at a follow-up examination 2 to 5 years later. Mean probing pocket depth (PPD) at baseline was 1.99+/-0.37 mm while mean overall change was 0.1 mm which amounts to an annual rate of 0.04 mm. Overall mean clinical attachment level (1.75+/-0.6 mm) at baseline resulted in mean attachment change of 0.28 mm (0.12 mm annually). Alveolar crestal height (ACH) at baseline (mean 2.05+/-0.85 mm) resulting in a mean net loss of 0.1 mm. Approximately 10% of all sites presented for the second visit with attachment loss exceeding the threshold (4.4% annually), while only 2.2% of all sites exhibited attachment gain (0.88% annually). Older individuals exhibited greater mean bone loss but the least amount of attachment loss. Current smokers exhibited greater disease progression compared to non-smokers. Tooth morbidity (0.17 teeth/patient/year) was associated with greater baseline CAL and ACH loss, and an assortment of systemic conditions. Subjects who harbored Bacteroides forsythus (Bf) at baseline had greater loss in ACH; likewise, these subjects experienced greater proportions of losing sites and twice as much tooth mortality compared to Bf-negative patients. Baseline clinical parameters correlated strongly with the outcome, i.e., subjects with deeper mean pocket depth at baseline exhibited greater increase in pocket depth overtime; while subjects with greater attachment loss at baseline exhibited greater attachment loss between the 1st and 2nd visits.
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Schenkman M, Cutson TM, Kuchibhatla M, Chandler J, Pieper CF, Ray L, Laub KC. Exercise to improve spinal flexibility and function for people with Parkinson's disease: a randomized, controlled trial. J Am Geriatr Soc 1998; 46:1207-16. [PMID: 9777901 DOI: 10.1111/j.1532-5415.1998.tb04535.x] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The effectiveness of an exercise intervention for people in early and midstage Parkinson's disease (stages 2 and 3 of Hoehn and Yahr) in improving spinal flexibility and physical performance in a sample of community-dwelling older people is described. DESIGN AND SETTING Fifty-one men and women, aged 55-84 years, identified through advertisement, local support groups, and local neurologists were enrolled into a randomized, controlled trial. Subjects were assigned randomly to an intervention or a usual care arm (i.e., no specific exercise). Of the original 51 participants, 46 completed the randomized, controlled trial. Participants in the exercise arm (n = 23) received individual instruction three times per week for 10 weeks. Participants in the usual care arm (n = 23) were "wait listed" for intervention. MEASUREMENTS Changes over 10 weeks in spinal flexibility (i.e., functional axial rotation) and physical performance (i.e., functional reach, timed supine to stand) were the primary outcome measures. RESULTS MANOVA conducted for the three primary outcome variables demonstrated significant differences (P < or = .05) between the two groups. Further analysis using ANOVA demonstrated significant differences between groups in functional axial rotation and functional reach for the intervention compared with the control group. There was no significant difference in supine to sit time. CONCLUSION Study results demonstrate that improvements in axial mobility and physical performance can be achieved with a 10-week exercise program for people in the early and midstages of PD.
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Clinical Trial |
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135 |
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Vaquero C, Sack M, Chandler J, Drossard J, Schuster F, Monecke M, Schillberg S, Fischer R. Transient expression of a tumor-specific single-chain fragment and a chimeric antibody in tobacco leaves. Proc Natl Acad Sci U S A 1999; 96:11128-33. [PMID: 10500141 PMCID: PMC17998 DOI: 10.1073/pnas.96.20.11128] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/1999] [Indexed: 12/13/2022] Open
Abstract
To evaluate the expression of different forms of a tumor-specific antibody in plants, we adapted a recently described Agrobacterium-mediated transient expression system. A recombinant single-chain Fv antibody (scFvT84.66) and a full-size mouse/human chimeric antibody (cT84.66) derived from the parental murine mAb T84. 66 specific for the human carcinoembryonic antigen were engineered into a plant expression vector. Chimeric T84.66 heavy and light chain genes were constructed by exchanging the mouse light and heavy chain constant domain sequences with their human counterparts and cloned into two independent plant expression vectors. In vivo assembly of full-size cT84.66 was achieved by simultaneous expression of the light and heavy chains after vacuum infiltration of tobacco leaves with two populations of recombinant Agrobacterium. Upscaling the transient system permitted purification of functional recombinant antibodies from tobacco leaf extracts within a week. His6-tagged scFvT84.66 was purified by immobilized metal affinity chromatography and cT84.66 by protein A affinity chromatography. Sufficient amounts of recombinant antibodies were recovered for detailed characterization by SDS/PAGE, Western blotting, and ELISA.
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research-article |
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Papanicolaou DA, Ather SN, Zhu H, Zhou Y, Lutkiewicz J, Scott BB, Chandler J. A phase IIA randomized, placebo-controlled clinical trial to study the efficacy and safety of the selective androgen receptor modulator (SARM), MK-0773 in female participants with sarcopenia. J Nutr Health Aging 2013; 17:533-43. [PMID: 23732550 DOI: 10.1007/s12603-013-0335-x] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Sarcopenia, the age-related loss of muscle mass [defined as appendicular LBM/Height2 (aLBM/ht2) below peak value by>1SD], strength and function, is a major contributing factor to frailty in the elderly. MK-0773 is a selective androgen receptor modulator designed to improve muscle function while minimizing effects on other tissues. OBJECTIVES The primary objective of this study was to demonstrate an improvement in muscle strength and lean body mass (LBM) in sarcopenic frail elderly women treated with MK-0773 relative to placebo. DESIGN This was a randomized, double-blind, parallel-arm, placebo-controlled, multicenter, 6-month study. Participants were randomized in a 1:1 ratio to receive either MK-0773 50mg b.i.d. or placebo; all participants received Vitamin D and protein supplementation. SETTING General community. PARTICIPANTS 170 Women aged ≥65 with sarcopenia and moderate physical dysfunction. MEASUREMENTS Dual energy X-ray absorptiometry, muscle strength and power, physical performance measures. RESULTS Participants receiving MK-0773 showed a statistically significant increase in LBM from baseline at Month 6 vs. placebo (p<0.001). Participants receiving both MK-0773 and placebo showed a statistically significant increase in strength from baseline to Month 6, but the mean difference between the two groups was not significant (p=0.269). Both groups showed significant improvement from baseline at Month 6 in physical performance measures, but there were no statistically significant differences between participants receiving MK-0773 and placebo. A greater number of participants experienced elevated transaminases in the MK-0773 group vs. placebo, which resolved after discontinuation of study therapy. MK-0773 was generally well-tolerated with no evidence of androgenization. CONCLUSIONS The MK-0773-induced increase in LBM did not translate to improvement in strength or function vs. placebo. The improvement of strength and physical function in the placebo group could be at least partly attributed to protein and vitamin D supplementation.
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Clinical Trial, Phase II |
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117 |
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Chandler JR, Goulding R, Moskowitz L, Quencer RM. Nasopharyngeal angiofibromas: staging and management. Ann Otol Rhinol Laryngol 1984; 93:322-9. [PMID: 6087710 DOI: 10.1177/000348948409300408] [Citation(s) in RCA: 113] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We propose a system for staging nasopharyngeal angiofibromas based on clinical evaluation and computerized tomography. Twenty-three patients with this pathologic diagnosis have been managed at the University of Miami/Jackson Memorial Medical Center in the past two decades. In 13 patients, the clinical diagnosis was confirmed by transnasal biopsy as a minor outpatient procedure. This avoided unnecessary diagnostic studies, shortened the hospital stay, and expedited treatment. Computerized tomography has replaced conventional x-ray studies and routine tomography, although angiography is still necessary for proper evaluation of larger tumors. Stage groupings recommended on the basis of this experience are stage I--tumor confined to nasopharynx; stage II--tumor extending into nasal cavity and/or sphenoid sinus; stage III--tumor extending into one or more of the following: antrum, ethmoid sinus, pterygomaxillary and infratemporal fossae, orbit, and/or cheek; and stage IV--tumor extending into cranial cavity. Surgical excision is recommended for stages I, II, and III. Stage IV tumors require surgical resection and/or radiation therapy with the possible addition of hormonal therapy.
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113 |
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Studenski S, Duncan PW, Chandler J. Postural responses and effector factors in persons with unexplained falls: results and methodologic issues. J Am Geriatr Soc 1991; 39:229-34. [PMID: 2005334 DOI: 10.1111/j.1532-5415.1991.tb01642.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Automatic postural responses and effector factors were examined in 10 persons with unexplained falls after clinical examination and 24 older controls. Fallers were more unstable than controls on clinical tests of balance (20% of fallers vs 79.2% of controls were able to stand on one foot (P less than .005), 40% of fallers and 100% of controls were stable while turning in place (P less than .001), postural stress test median score was 12 for fallers and 20 for controls (P less than 0.001). We found prolonged tibialis anterior latency (fallers 158.8 +/- 23.7, controls 143.2 +/- 15.7 milliseconds, P = 0.03), marked losses in ankle strength (dorsiflexion: faller 3.2 +/- 2.9, controls 8.9 +/- 4.2 foot-pounds, P less than 0.001; plantarflexion: fallers 7.9 +/- 5.3, controls 21.4 +/- 11.1 foot-pounds, P less than 0.001), and decreases in range of motion (ankle plantarflexion: fallers 29.2 +/- 7.0, controls 37.8 +/- 12.4 degrees, P = 0.02). Gastrocnemius latency and electromyographic (EMG) measures of sequence showed no differences between fallers and controls. Sequence measures were not symmetric between the lower extremities in either fallers or controls. In this population of persons with unexplained falls who demonstrated substantial impairments in functional balance, effector factors appear more impaired than automatic postural responses. Alternatively, contemporary analysis of automatic postural responses may require further development before it can be useful to study balance problems in older persons.
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111 |
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Duerkop BA, Varga J, Chandler JR, Peterson SB, Herman JP, Churchill MEA, Parsek MR, Nierman WC, Greenberg EP. Quorum-sensing control of antibiotic synthesis in Burkholderia thailandensis. J Bacteriol 2009; 191:3909-18. [PMID: 19376863 PMCID: PMC2698390 DOI: 10.1128/jb.00200-09] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Accepted: 04/06/2009] [Indexed: 11/20/2022] Open
Abstract
The genome of Burkholderia thailandensis codes for several LuxR-LuxI quorum-sensing systems. We used B. thailandensis quorum-sensing deletion mutants and recombinant Escherichia coli to determine the nature of the signals produced by one of the systems, BtaR2-BtaI2, and to show that this system controls genes required for the synthesis of an antibiotic. BtaI2 is an acyl-homoserine lactone (acyl-HSL) synthase that produces two hydroxylated acyl-HSLs, N-3-hydroxy-decanoyl-HSL (3OHC(10)-HSL) and N-3-hydroxy-octanoyl-HSL (3OHC(8)-HSL). The btaI2 gene is positively regulated by BtaR2 in response to either 3OHC(10)-HSL or 3OHC(8)-HSL. The btaR2-btaI2 genes are located within clusters of genes with annotations that suggest they are involved in the synthesis of polyketide or peptide antibiotics. Stationary-phase cultures of wild-type B. thailandensis, but not a btaR2 mutant or a strain deficient in acyl-HSL synthesis, produced an antibiotic effective against gram-positive bacteria. Two of the putative antibiotic synthesis gene clusters require BtaR2 and either 3OHC(10)-HSL or 3OHC(8)-HSL for activation. This represents another example where antibiotic synthesis is controlled by quorum sensing, and it has implications for the evolutionary divergence of B. thailandensis and its close relatives Burkholderia pseudomallei and Burkholderia mallei.
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Research Support, N.I.H., Extramural |
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105 |
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Zimmerman SI, Girman CJ, Buie VC, Chandler J, Hawkes W, Martin A, Holder L, Hebel JR, Sloane PD, Magaziner J. The prevalence of osteoporosis in nursing home residents. Osteoporos Int 1999; 9:151-7. [PMID: 10367043 DOI: 10.1007/s001980050129] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
This study describes the prevalence of osteoporosis in a statewide sample of nursing home residents. Composite forearm bone mineral density (BMD) (including the distal radius and the distal ulna) of 1475 residents aged 65 years and older from 34 randomly selected, stratified nursing homes was assessed. BMD was expressed with reference to World Health Organization diagnostic criteria. Trends with age, gender and race were consistent with other populations. However, prevalence estimates were higher than community-based age-specific rates. The prevalence of osteoporosis for white female residents increased from 63.5% for women aged 65-74 years to 85.8% for women over 85 years of age. Only 3% had composite forearm BMD within 1 standard deviation of the young adult mean. The significance of the high prevalence of low BMD in nursing home residents is the increased fracture risk it may confer. In community cohorts of white women, the risk of hip fracture increases approximately 50% for every 1 standard deviation decrease in bone mass. However, the degree to which BMD contributes to fracture risk in this population has not been well established.
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102 |
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Schenkman M, Cutson TM, Kuchibhatla M, Chandler J, Pieper C. Reliability of impairment and physical performance measures for persons with Parkinson's disease. Phys Ther 1997; 77:19-27. [PMID: 8996460 DOI: 10.1093/ptj/77.1.19] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND PURPOSE Parkinson's disease (PD) is characterized by rigidity, postural instability, bradykinesia, and tremor, as well as other musculoskeletal impairments and functional limitations. The purpose of this investigation was to determine the reliability and stability of measures of impairments and physical performance for people in the early and middle stages of PD, Subjects. Thirteen men and 2 women in Hoehn and Yahr stages 2 and 3 of PD participated. Their mean age was 74.5 years (SD = 5.7, range = 64-84). METHODS Thirteen impairment-level variables and 8 physical performance variables were measured. Measurements were taken on two consecutive days and again a week later on the corresponding two consecutive days. Reliability and stability were assessed using analysis of variance and intraclass correlation coefficients (ICCs). RESULTS Test-retest reliability (ICCs) of variables ranged from .69 (hamstring muscle length) to .97 (lumbar flexion). Intraclass correlation coefficients were .85 or greater for 10 of the variables. CONCLUSIONS AND DISCUSSION The results suggest that in the early and middle stages of PD, many of the measures of impairment and physical performance are relatively stable.
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Wilkens S, Dunn SD, Chandler J, Dahlquist FW, Capaldi RA. Solution structure of the N-terminal domain of the delta subunit of the E. coli ATPsynthase. NATURE STRUCTURAL BIOLOGY 1997; 4:198-201. [PMID: 9164460 DOI: 10.1038/nsb0397-198] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
NMR studies of the delta subunit of the Escherichia coli F1F0-ATPsynthase reveal that it consists of an N-terminal six alpha-helix bundle and a less well ordered C terminus. Both domains are part of one of two separate connections between F1 and F0.
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Letter |
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99 |
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Jernigan TL, Archibald S, Hesselink JR, Atkinson JH, Velin RA, McCutchan JA, Chandler J, Grant I. Magnetic resonance imaging morphometric analysis of cerebral volume loss in human immunodeficiency virus infection. The HNRC Group. ARCHIVES OF NEUROLOGY 1993; 50:250-5. [PMID: 8442702 DOI: 10.1001/archneur.1993.00540030016007] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Magnetic resonance imaging was used to compare male subjects seropositive for antibody to human immunodeficiency virus type 1 (HIV positive), with and without medical symptoms, with two groups of men who were seronegative (HIV negative). The control subjects included men at high risk for exposure to HIV-1 and those at low risk. None of the HIV-positive subjects met criteria for HIV-associated dementia or had detectable opportunistic brain disease. Quantitative image-analytic techniques were used to estimate volumes of ventricular and cortical cerebrospinal fluid, cerebral white matter, and cortical and subcortical gray matter structures. Relative to low-risk group control subjects and asymptomatic HIV-positive subjects, nondemented but medically symptomatic HIV-positive subjects showed significant increases in cerebrospinal fluid, reduced volume of cerebral white matter, and reduced cerebral gray matter volumes. Unexpectedly, however, some cerebrospinal fluid increases and gray matter volume decreases were present in the seronegative high-risk control subjects as well.
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Chakrabarti A, Sharma SC, Chandler J. Epidemiology and pathogenesis of paranasal sinus mycoses. Otolaryngol Head Neck Surg 1992; 107:745-50. [PMID: 1470451 DOI: 10.1177/019459988910700606.1] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In a prospective study, 50 cases of paranasal sinus mycoses were diagnosed in 2 years out of 119 clinically suspected patients from north India. Young men from rural areas were most commonly afflicted. Patients with paranasal sinus mycoses could be grouped in three clinical varieties: noninvasive, 31; invasive, 17; allergic, 2. Maxillary and ethmoid were the common sinuses concurrently involved in these patients, whereas sphenoid and frontal sinuses were also affected in invasive variety. Aspergillus flavus (80%) was the most common isolate, followed by A. fumigatus (6%). Alternaria species was identified in two patients with noninvasive granuloma. In invasive variety, Rhizopus arrhizus and Candida albicans were the causative agents in two patients and one patient, respectively. Regarding pathogenesis besides epidemiologic factors, the immunologic factors were also evaluated. It was found that presence or absence of precipitating antibody against antigens from the etiologic agents correlates well with disease progression. Allergic factor was found in all varieties, though presence of cell-mediated immunity was demonstrated in 29% patients with noninvasive granuloma only. The combination of skin test against aspergillin and precipitin demonstration at the outset will therefore help in preliminary screening.
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Seyedsayamdost MR, Chandler JR, Blodgett JAV, Lima PS, Duerkop BA, Oinuma KI, Greenberg EP, Clardy J. Quorum-sensing-regulated bactobolin production by Burkholderia thailandensis E264. Org Lett 2010; 12:716-9. [PMID: 20095633 PMCID: PMC2821070 DOI: 10.1021/ol902751x] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
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Bacterial acyl-homoserine lactones upregulated an uncharacterized gene cluster (bta) in Burkholderia thailandensis E264 to produce an uncharacterized polar antibiotic. The antibiotic is identified as a mixture of four bactobolins. Annotation of the bta cluster allows us to propose a biosynthetic scheme for bactobolin and reveals unusual enzymatic reactions for further study.
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Research Support, N.I.H., Extramural |
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LaFayette SL, Houle D, Beaudoin T, Wojewodka G, Radzioch D, Hoffman LR, Burns JL, Dandekar AA, Smalley NE, Chandler JR, Zlosnik JE, Speert DP, Bernier J, Matouk E, Brochiero E, Rousseau S, Nguyen D. Cystic fibrosis-adapted Pseudomonas aeruginosa quorum sensing lasR mutants cause hyperinflammatory responses. SCIENCE ADVANCES 2015; 1:e1500199. [PMID: 26457326 PMCID: PMC4597794 DOI: 10.1126/sciadv.1500199] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 06/06/2015] [Indexed: 05/23/2023]
Abstract
Cystic fibrosis lung disease is characterized by chronic airway infections with the opportunistic pathogen Pseudomonas aeruginosa and severe neutrophilic pulmonary inflammation. P. aeruginosa undergoes extensive genetic adaptation to the cystic fibrosis (CF) lung environment, and adaptive mutations in the quorum sensing regulator gene lasR commonly arise. We sought to define how mutations in lasR alter host-pathogen relationships. We demonstrate that lasR mutants induce exaggerated host inflammatory responses in respiratory epithelial cells, with increased accumulation of proinflammatory cytokines and neutrophil recruitment due to the loss of bacterial protease- dependent cytokine degradation. In subacute pulmonary infections, lasR mutant-infected mice show greater neutrophilic inflammation and immunopathology compared with wild-type infections. Finally, we observed that CF patients infected with lasR mutants have increased plasma interleukin-8 (IL-8), a marker of inflammation. These findings suggest that bacterial adaptive changes may worsen pulmonary inflammation and directly contribute to the pathogenesis and progression of chronic lung disease in CF patients.
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Abstract
Infection in the marrow of the temporal, occipital, and sphenoid bones is an uncommon, but increasing occurrence. It is usually secondary to infections beginning in the external auditory canal and is caused almost uniformly by the gram negative Pseudomonas aeruginosa bacteria. Technetium and gallium scintigraphy help in the early detection of such infections while CT scans demonstrate dissolution of bone in well-developed cases. Headache is the predominant symptom. Dysphagia, hoarseness, and aspiration herald the inevitable march of cranial nerves. We have diagnosed and treated 17 cases of osteomyelitis of the skull base. Although the total mortality rate is 53%, it is now a curable disease. Six of our last 8 patients remain alive, although 1 is still under treatment. Treatment is medical and requires the long-term concomitant intravenous administration of an aminoglycoside and a broad spectrum semisynthetic penicillin effective against the causative organism.
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Webster J, Chandler J, Battistutta D. Pregnancy outcomes and health care use: effects of abuse. Am J Obstet Gynecol 1996; 174:760-7. [PMID: 8623818 DOI: 10.1016/s0002-9378(96)70461-1] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE Our purpose was to determine whether pregnancy and neonatal outcomes differed between abused and nonabused women. STUDY DESIGN Women (N=1014) who completed an abuse questionnaire during pregnancy were followed up after delivery. The 242 women reporting past abuse and the 59 women reporting abuse in pregnancy were grouped in terms of recency and severity of domestic abuse, and their pregnancy and birth outcomes were compared with those of nonabused women with the chi-square test, analysis of variance, and multivariate logistic regression techniques. RESULTS Abused women smoked more cigarettes (p<0.0001) and took more prescription drugs (p<0.03) and antidepressants (p>0.05) than nonabused women; they were more likely to have epilepsy (p=0.0002) and asthma (p=0.0018), and also they used social work services more often (p>0.0001). Obstetric histories revealed a higher incidence of miscarriage (p=0.0014), two or more pregnancy terminations (p>0.0001), and neonatal death (p=0.0503) among the abused group. Although abused women delivered infants whose mean birth weight was 132 gm lower than that of nonabused women, the difference was not significant after adjustments were made. Mildly and moderately abused women were admitted to the hospital more frequently during pregnancy (p=0.0067). CONCLUSION Domestic abuse adds significantly to the cost of health care during pregnancy and is associated with poor maternal and fetal outcomes.
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