Genetic covariation of pelvic organ and elbow mobility in twins and their sisters

A range of environmental risk factors, with childbirth the most notable, have been associated with the development of pelvic organ prolapse and urinary incontinence. However, indications of genetic influence (positive family histories, ethnic differences) have prompted research into the heritability of measures of pelvic organ descent and joint mobility, which have also been associated with prolapse and incontinence. Genes appear to influence about half of the variation in these measures and, furthermore, the pelvic organ measures are associated with elbow hyperextension at a phenotypic level (r approximate to .2). We examined these measures in young, nulligravid women to determine if their association is due to a common genetic source. Data were collected from 178 Caucasian female co-twins and non-twin sisters, 50 of whom returned to be retested, which allowed reliability to be estimated and unreliable variance to be isolated in the multivariate analyses. Structural equation modeling was used to estimate genetic associations between latent elbow and bladder mobility factors for which heritabilities were estimated to be 0.80 and 0.64 respectively. The association between these factors appeared to be mediated by common genes (genetic r = .48, non-shared environmental r = -.06), with genes influencing latent elbow mobility accounting for 14% of the variation in latent bladder mobility. We speculate that genes influencing connective tissue structure may underlie this association.

Determination of external and internal mass transfer limitation in nitrifying microbial aggregates

In this article we present a study of the effects of external and internal mass transfer limitation of oxygen in a nitrifying system. The oxygen uptake rates (OUR) were measured on both a macro-scale with a respirometric reactor using off-gas analysis (Titrimetric and Off-Gas Analysis (TOGA) sensor) and on a micro-scale with microsensors. These two methods provide independent, accurate measurements of the reaction rates and concentration profiles around and in the granules. The TOGA sensor and micro-sensor measurements showed a significant external mass transfer effect at low dissolved oxygen (DO) concentrations in the bulk liquid while it was insignificant at higher DO concentrations. The oxygen distribution with anaerobic or anoxic conditions in the center clearly shows major mass transfer limitation in the aggregate interior. The large drop in DO concentration of 22 - 80% between the bulk liquid and aggregate surface demonstrates that the external mass transfer resistance is also highly important. The maximum OUR even for floccular biomass was only attained at much higher DO concentrations ( approximate to 8 mg/L) than typically used in such systems. For granules, the DO required for maximal activity was estimated to be > 20mg/L, clearly indicating the effects of the major external and internal mass transfer limitations on the overall biomass activity. Smaller aggregates had a larger volumetric OUR indicating that the granules may have a lower activity in the interior part of the aggregate. (C) 2004 Wiley Periodicals, Inc.

Challenges for simultaneous nitrification, denitrification, and phosphorus removal in microbial aggregates: mass transfer limitation and nitrous oxide production

The microbial community composition and activity was investigated in aggregates from a lab-scale bioreactor, in which nitrification, denitrification and phosphorus removal occurred simultaneously. The biomass was highly enriched for polyphosphate accumulating organisms facilitating complete removal of phosphorus from the bulk liquid; however, some inorganic nitrogen still remained at the end of the reactor cycle. This was ascribed to incomplete coupling of nitrification and denitrification causing NO3- accumulation. After 2 h of aeration, denitrification was dependent on the activity of nitrifying bacteria facilitating the formation of anoxic zones in the aggregates; hence, denitrification could not occur without simultaneous nitrification towards the end of the reactor cycle. Nitrous oxide was identified as a product of denitrification, when based on stored PHA as carbon source. This observation is of critical importance to the outlook of applying PHA-driven denitrification in activated sludge processes. (c) 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.

Measuring mobility in frail older people: reliability and validity of the Physical Mobility Scale

Objectives: The study was designed to show the validity and reliability of scoring the Physical Mobility Scale (PMS). PMS was developed by physiotherapists working in residential aged care to specifically show resident functional mobility and to provide information regarding each resident's need for supervision or assistance from one or two staff members and equipment during position changes, transfers, mobilising and personal care. Methods: Nineteen physiotherapists of varying backgrounds and experience scored the performances of nine residents of care facilities from video recordings. The performances were compared to scores on two 'gold standard' assessment tools. Four of the physiotherapists repeated the evaluations. Results: The PAIS showed excellent content validity and reliability. Conclusions: The PAIS provides graded performance of physical mobility, including level of dependency on staff and equipment. This is a major advantage over existing functional assessment tools. There is no need for specific training for physiotherapists to use the tool.

A possible smoking susceptibility locus on chromosome 11p12: Evidence from sex-limitation linkage analyses in a sample of Australian twin families

Many twin studies have identified sex differences in the influence of genetic and environmental factors on smoking behaviors. We explore the evidence for sex differences for smoking initiation and cigarette consumption in a sample of Australian twin families, and extend these models to incorporate sex differences in linkage analyses for these traits. We further examine the impact of including or excluding non-smokers in genetic analyses of tobacco consumption. Accounting for sex differences improved linkage results in some instances. We identified one region suggestive of linkage on chromosome 11p12. This locus, as well as another region identified on chromosome 6p12, replicates regions identified in previous studies.

Active genetic elements present in the locus of enterocyte effacement in Escherichia coli O26 and their role in mobility

The locus of enterocyte effacement (LEE) is a large multigene chromosomal segment encoding gene products responsible for the generation of attaching and effacing lesions in many diarrheagenic Escherichia coli strains. A recently sequenced LEE harboring a pathogenicity island (PAI) from a Shiga toxin E. coli serotype 026 strain revealed a LEE PAI (designated LEE 026) almost identical to that obtained from a rabbit-specific enteropathogenic 015:H- strain. LEE 026 comprises 59,540 bp and is inserted at 94 min within the mature pheU tRNA locus. The LEE 026 PAI is flanked by two direct repeats of 137 and 136 bp (DR1 and DR2), as well as a gene encoding an integrase belonging to the P4 integrase family. We examined LEE 026 for horizontal gene transfer. By generating mini-LEE plasmids harboring only DR1 or DR2 with or without the integrase-like gene, we devised a simple assay to examine recombination processes between these sequences. Recombination was shown to be integrase dependent in a Delta recA E. coli K-12 strain background. Recombinant plasmids harboring a single direct repeat cloned either with or without the LEE 026 integrase gene were found to insert within the chromosomal pheU locus of E. coli K-12 strains with equal efficiency, suggesting that an endogenous P4-like integrase can substitute for this activity. An integrase with strong homology to the LEE 026 integrase was detected on the K-12 chromosome associated with the leuX tRNA locus at 97 min. Strains deleted for this integrase demonstrated a reduction in the insertion frequency of plasmids harboring only the DR into the pheU locus. These results provide strong evidence that LEE-harboring elements are indeed mobile and suggest that closely related integrases present on the chromosome of E. coli strains contribute to the dynamics of PAI mobility.

Inflammatory markers are associated with ventilatory limitation and muscle dysfunction in obstructive lung disease in well functioning elderly subjects

Background: Inflammatory markers are increased in chronic obstructive pulmonary disease ( COPD) and are hypothesised to play an important part in muscle dysfunction and exercise intolerance. Methods: The Health Aging and Body Composition ( Health ABC) study is a prospective observational cohort of well functioning individuals aged 70 - 79 years. A cross sectional analysis of the baseline data was conducted to examine the association between inflammatory markers and ventilatory limitation, muscle strength, and exercise capacity. These associations were compared in participants with and without obstructive lung disease ( OLD). Results: Of the 3075 participants enrolled in the Health ABC cohort, OLD was identified by spirometric testing in 268 participants and 2005 participants had normal spirometric results. Of the participants with OLD, 35%, 38%, and 27% participants had mild, moderate, and severe OLD, respectively. Participants with OLD had lower quadriceps strength (102.5 Nm v 108.9 Nm, p = 0.02), lower maximum inspiratory pressure (64.7 cm H2O v 74.2 cm H2O, p< 0.0001), higher systemic interleukin (IL)-6 levels (2.6 pg/ml v 2.2 pg/ml, p< 0.0001), and higher C-reactive protein (CRP) levels (3.5 mg/l v 2.5 mg/l, p< 0.0001) than those with normal spirometry. In participants with OLD and those with normal spirometry, forced expiratory volume in 1 second (FEV1) was associated with IL-6 ( adjusted regression coefficients (beta) = -5.3 (95% CI -9.1 to -1.5) and -3.1 (95% CI -4.3 to -1.9), respectively). IL-6 and TNF were also associated with quadriceps strength among participants with OLD and those with normal spirometry (beta = -6.4 (95% CI -12.8 to -0.03) and -3.4 (95% CI -5.4 to -1.3), respectively, for IL-6 and beta = -10.1 (95% CI -18.7 to -1.5) and -3.8 (95% CI -7 to -0.6), respectively, for TNF). IL-6, quadriceps strength, and maximum inspiratory pressures were independent predictors of reduced exercise capacity in both groups. Conclusions: In well functioning elderly subjects with or without OLD, IL-6 is associated with reduced FEV1, quadriceps strength, and exercise capacity.

Nitrogen, phosphorus, silica, and carbon in Moreton Bay, Queensland, Australia: Differential limitation of phytoplankton biomass and production

Subtropical estuaries have received comparatively little attention in the study of nutrient loading and subsequent nutrient processing relative to temperate estuaries. Australian estuaries are particularly susceptible to increased nutrient loading and eutrophication, as 75% of the population resides within 200 km of the coastline. We assessed the factors potentially limiting both biomass and production in one Australian estuary, Moreton Bay, through stoichiometric comparisons of nitrogen (N), phosphorus (P), silicon (Si), and carbon (C) concentrations, particulate compositions, and rates of uptake. Samples were collected over 3 seasons in 1997-1998 at stations located throughout the bay system, including one riverine endmember site. Concentrations of all dissolved nutrients, as well as particulate nutrients and chlorophyll, declined 10-fold to 100-fold from the impacted western embayments to the eastern, more oceanic-influenced regions of the bay during all seasons. For all seasons and all regions, both the dissolved nutrients and particulate biomass yielded N : P ratios < 6 and N : Si ratios < 1. Both relationships suggest strong limitation of biomass by N throughout the bay. Limitation of rates of nutrient uptake and productivity were more complex. Low C : N and C : P uptake ratios at the riverine site suggested light limitation at all seasons, low N : P ratios suggested some degree of N limitation and high N : Si uptake ratios in austral winter suggested Si limitation of uptake during that season only. No evidence of P limitation of biomass or productivity was evident.

Validation and reliability of the Modified Elderly Mobility Scale

Objective: To establish concurrent validity, interrater and test-retest reliability of the Modified Elderly Mobility Scale (MEMS). Methods: Ninety elderly patients were scored on the MEMS. To establish concurrent validity, 75 patients MEMS scores were compared to Functional Independence Measure (FIM) scores using Spearman's correlation. Videotaped patient performances were used to establish interrater and test-retest reliability using percentage absolute agreement and intraclass correlation coefficients (ICCs). Results: The total MEMS score demonstrated a significant association with the motor (r = 0.725) and total FIM scores (r = 0.718). Absolute agreement for interrater reliability was greater than 93% for all test items, with 97 and 98% for the two new measures, respectively. Test-retest reliability demonstrated similar high levels of absolute agreement and had ICCs ranging from 0.870 to 1.0. Conclusions: The MEMS is a quick, valid and reliable test of motor function of elderly patients with a spread of functional levels.