Sagittal patellar flexion angle: a novel clinically validated patellar height measurement reflecting patellofemoral kinematics useful throughout knee flexion.

PURPOSE: Patellar height measurements on lateral radiographs are dependent on knee flexion which makes standardisation of measurements difficult. This study described a plain radiographic measurement of patellar sagittal height which reflects patellofemoral joint kinematics and can be used at all degrees of flexion. METHODS: The study had two parts. Part one involved 44 normal subjects to define equations for expected patellar position based on the knee flexion angles for three new patellar height measurements. A mixed model regression with random effect for individual was used to define linear and polynomial equations for expected patellar position relating to three novel measurements of patella height: (1) patellar progression angle (trochlea), (2) patellar progression angle (condyle) and (3) sagittal patellar flexion. Part two was retrospective and involved applying these measurements to a surgical cohort to identify differences between expected and measured patellar position pre- and post-operatively. RESULTS: All three measurements provided insight into patellofemoral kinematics. Sagittal patellar flexion was the most useful with the least residual error, was the most reliable, and demonstrated the greatest detection clinically. CONCLUSIONS: Clinically applied radiographic measurements have been described for patellar height which reflect the sagittal motion of the patella and can be used regardless of the degree of flexion in which the radiograph was taken. The expected sagittal patellar flexion linear equation should be used to calculate expected patellar height. LEVEL OF EVIDENCE: IV.

A single phosphorus treatment doubles growth of cyanobacterial lichen transplants.

Lichens are reputedly slow growing and become unhealthy or die in response to supplements of the usual limiting resources, such as water and nitrogen. We found, however, that the tripartite cyanobacterial lichen Lobaria pulmonaria doubled in annual biomass growth after a single 20-minute immersion in a phosphorus solution (K2HPO4), as compared to controls receiving no supplemental phosphorus. This stimulation of cyanolichens by phosphorus has direct relevance to community and population ecology of lichens, including improving models of lichen performance in relation to air quality, improving forest management practices affecting old-growth associated cyanolichens, and understanding the distribution and abundance of cyanolichens on the landscape. Phosphorus may be as important a stimulant to cyanobacterial-rich lichen communities as it is to cyanobacteria in aquatic ecosystems.

Treatment of patella tendinopathy by distalising tibial tubercle osteotomy.

Patella tendinopathy condition is often resistant to conservative treatment. We report a case of patella tendinopathy treated by distalisation of the tibial tubercle with excellent long-term result.

Access to drinking-water and arsenicosis in Bangladesh.

The discovery of arsenic contamination in groundwater has challenged efforts to provide safe drinking-water to households in rural Bangladesh. Two nationally-representative surveys in 2000 and 2002 investigated water-usage patterns, water-testing, knowledge of arsenic poisoning, and behavioural responses to arsenic contamination. Knowledge of arsenicosis rose between the two surveys among women from 42% to 64% but awareness of consequences of arsenic remained limited; only 13% knew that it could lead to death. Behavioural responses to arsenic have been limited, probably in part because of the lack of concern but also because households are uncertain of how best to respond and have a strong preference for tubewell water even when wells are known to be contaminated. Further work conducted by the survey team highlighted the difficulties in providing alternative sources of water, with many households switching back to their original sources of water.

The effect of arsenic mitigation interventions on disease burden in Bangladesh.

Many interventions have been advocated to mitigate the impact of arsenic contamination of drinking water in Bangladesh. However, there are few data on the true magnitude of arsenic-related disease in Bangladesh nationally. There has also been little consideration given to possible adverse effects of such interventions, in particular, diarrheal disease. The purpose of this study was to estimate and compare the likely impacts of arsenic mitigation interventions on both arsenic-related disease and water-borne infectious disease. We found that arsenic-related disease currently results in 9,136 deaths per year and 174,174 disability-adjusted life years (DALYs; undiscounted) lost per year in those exposed to arsenic concentrations > 50 microg/L. This constitutes 0.3% of the total disease burden in Bangladesh in terms of undiscounted DALYs. We found intervention to be of overall benefit in reducing disease burden in most scenarios examined, but the concomitant increase in water-related infectious disease significantly reduced the potential benefits gained from intervention. A minimum reduction in arsenic-related DALYs of 77% was necessary before intervention achieved any reduction in net disease burden. This is assuming that interventions were provided to those exposed to > 50 microg/L and would concomitantly result in a 20% increase in water-related infectious disease in those without access to adequate sanitation. Intervention appears to be justified for those populations exposed to high levels of arsenic, but it must be based on exposure levels and on the effectiveness of interventions not only in reducing arsenic but in minimizing risk of water-related infections. Key words: arsenic/adverse effects, Bangladesh, burden of disease, diarrhea, risk assessment, water pollutants, water supply.

Soil Chemistry in a Loblolly/Longleaf Pine Forest with Interval Burning.

We examined the 30-yr cumulative effects of prescribed fires at intervals of 1, 2, 3, and 4 yr in a loblolly and longleaf pine forest in the Coastal Plain of South Carolina. The fine fraction of the forest floor (Oe + Oa horizons) contained much more carbon and nitrogen per unit area in the control plots (1.7 and 0.05 kg/m2 , respectively) than in the 1-yr burn interval plots (0.4 and 0.007 kg/m2 , respectively). Mineral soils (0-0.2 m depth) were highly variable in chemistry, and showed only slight differences across the burning treatments for nitrogen and sulfur. No trends were apparent for phosphorus in the forest floor or mineral soil; differences in acidity and extractable cations were also slight. The nutrient content of foliage was generally low, with no differences across burning intervals. Our results are consistent with earlier studies that showed the biogeochemical effects of repeated surface fires in southern pine forests are generally limited to the forest floor, with the possible exception of overall reductions in nitrogen cycling.

Searching for an optimum solution to the Bangladesh arsenic crisis.

Searching for an optimum solution to the Bangladesh arsenic crisis: Thirty years ago Bangladesh experienced very high levels of infant and child mortality, much of it due to water-borne disease in deltaic conditions where surface water was highly polluted. In what appeared to be one of the great public health achievements, 95% of the population were converted to drinking bacteria-free tubewell water from underground aquifers. Recently, it has been shown that perhaps 20% of this water is arsenic contaminated and alternatives to tubewell water have been sought. This paper reports on two national surveys collaboratively carried out in 2000 by the Health Transition Centre, Australian National University and Mitra and Associates, Dhaka: A census of tubewells and a household survey of tubewell use and arseniosis. The study found that the tubewell revolution has been promoted not only by health considerations but also by the demand for a household water facility and the desire by women to reduce workloads associated with using surface water. Because of this, and because the population had absorbed the message about safe tubewell water, it is argued that the movement away from the use of tubewell water should be as limited as possible, even if this means using safe tubewells which are often found in the neighbourhood. To enable such a move the most urgent need is not changing the source of water but comprehensive national water testing providing essential information to households about which wells are safe and which are not.

Intervention trial to assess arsenic exposure from food crops in Bangladesh.

The authors assessed the contribution of food irrigated with arsenic-contaminated water to human exposure to arsenic in Bangladesh. An intervention trial was conducted in a village in the Jessore District of Bangladesh, where irrigation water had been field-tested in March 2000 and was found to contain arsenic with concentrations ranging from 100 to 500 microg/l. In May 2000, a random sample of 63 households was selected from the village, and 1 eligible person from each household was recruited to the study and randomized to an intervention or control group. The intervention group received food purchased from a village where irrigation water was found to contain < 10 microg/l arsenic. The control group received food purchased from markets in the study village, where irrigation water was found to contain > 100 microg/l arsenic. Pre- and postintervention urine samples were collected for urinary arsenic speciation assays. Preintervention, the mean urinary total arsenic concentrations were 139.25 microg/l and 129.15 microg/l for the intervention and control groups, respectively. These concentrations did not change significantly following intervention. Arsenic concentrations in samples of selected raw and cooked foods from the low-contamination area did not contain less arsenic than samples from the high-contamination area. Further studies to investigate the arsenic content of food grown in areas with high and low arsenic contamination of irrigation water are recommended.

Lifecourse Urbanization, Social Demography, and Health Outcomes among a National Cohort of 71,516 Adults in Thailand.

We examine the influence of urbanization on household structure, social networks, and health in Thailand. We compare lifetime urban or rural dwellers and those who were rural as children and urban as adults. Data derived from a large national cohort of 71,516 Sukhothai Thammathirat Open University adult students participating in an on-going longitudinal study of the health-risk transition in Thailand. The rural-urban group, one-third of cohort households, was significantly different from other groups (e.g., smaller households). The rural-rural and the urban-urban groups often were the two extremes. Urbanization, after adjusting for covariates, was a risk factor for poor overall health and depression. Urbanization is a mediator of the health-risk transition underway in Thailand. Health programs and policies directed at transitional health outcomes should focus on the health risks of the urbanizing population, in particular smoking, drinking, low social trust, and poor psychological health.

Erythrophore cell response to food-associated pathogenic bacteria: implications for detection.

Cell-based biosensors have been proposed for use as function-based detectors of toxic agents. We report the use of Betta splendens chromatophore cells, specifically erythrophore cells, for detection of food-associated pathogenic bacteria. Evaluation of erythrophore cell response, using Bacillus spp., has revealed that this response can distinguish pathogenic Bacillus cereus from a non-pathogenic B. cereus ΔplcR deletion mutant and a non-pathogenic Bacillus subtilis. Erythrophore cells were exposed to Salmonella enteritidis, Clostridium perfringens and Clostridium botulinum. Each bacterial pathogen elicited a response from erythrophore cells that was distinguished from the corresponding bacterial growth medium, and this observed response was unique for each bacterial pathogen. These findings suggest that erythrophore cell response has potential for use as a biosensor in the detection and toxicity assessment for food-associated pathogenic bacteria.

A randomised intervention trial to assess two arsenic mitigation options in Bangladesh.

Arsenic groundwater contamination in Bangladesh warrants immediate remediation. This randomised controlled intervention trial was conducted to determine the effectiveness of two possible interventions: dug wells and three-pitcher filters. A total of 640 individuals participated with 218 randomised to the dug well group, 216 to the three-pitcher group and 206 to a control group. Data were collected at baseline and at 1, 6 and 12 months after the intervention. Self reported compliance with dug wells remained below 20% during the entire 12 months of the study. The compliance with the three-pitcher filters decreased after 6 months and became similar to the compliance of the dug well group after 12 months. A substantial decrease in urinary arsenic metabolites occurred only among those who were compliant with dug wells and three-pitcher filter systems after 1 month of intervention as opposed to control participants. However, a persistent reduction in urinary arsenic concentrations was observed only among the dug well users after 12 months of intervention. Our results show that a functional dug well could be offered as a long-term alternative to tube wells, but use of this option is likely to be low, unless appropriate behavioural change measures are taken. Our study also demonstrates that arsenic removal technologies such as three-pitcher filters are an effective option as a short-term measure. The three-pitcher filters that are not adequately maintained are not an effective option for a year. These arsenic removal technologies may be even harmful in the long term if the resultant water quality is not properly monitored.

Pretransitional population control and equilibrium.

A persistent theme in much anthropological writing is the concept of the deliberate control of population numbers by hunter-gatherers as a means of achieving moderate family size, adequate nutrition, and constrained adult mortality. An analysis of the mix of theory and field evidence that led to this conclusion finds the case not proven. On the contrary, Malthusian constraints can operate, and probably did operate, to produce a hunter-gatherer society where most adults were reasonably robust and healthy even though child mortality was high and life expectancy short. The absence of population limitation in pre-Neolithic times implies high mortality as well as high fertility, and weakens the argument positing a Neolithic mortality crisis.

Responses of fish chromatophore-based cytosensor to a broad range of biological agents.

A cytosensor based on living chromatophores from Betta splendens Siamese fighting fish was used to test several classes of biologically active agents. Tested agents include neurotransmitters, adenyl cyclase activators, cytoskeleton effectors, cell membrane effectors and protein synthesis inhibitors. Characteristic cell responses were analyzed, and potential cytosensor applications were considered. Streptococcus pyogenes toxins streptolysin S and streptolysin O, Clostridium tetani tetanolysin, Staphylococcus aureus alpha-toxin and Vibrio parahemolyticus hemolysin, all bacterial toxins that act on cell membranes, elicited a strong response from chromatophores. A comparison of purified toxin to actual bacterial culture from Vibrio parahemolyticus demonstrated a nearly identical chromatophore cell response pattern. This suggests that the cytosensor response is reflective of bacterial toxin production.

Blind and naive classification of toxicity by fish chromatophores.

Cellular and molecular pathways involved in the ability of animals to change color have been studied previously as biosensors and cytosensors of active and toxic agents, but such studies generally have been limited to just a few standardized agents. Here we describe the performance of cultured chromatophore pigment cells from the fin tissue of Siamese fighting fish as sensors of toxic agents under blind sampling conditions at the September 2002 EILATox-Oregon Workshop. Detection was accomplished by monitoring motor protein-mediated movements of cellular pigment in chromatophores at both the gross population level as well as in singly imaged cells. Pigment responses were recorded both during the exposure of chromatophores to each blind sample as well as afterwards when the cells were examined for after-effects by challenging them with clonidine, an adrenergic drug that induces standardized pigment movements. After recording all results and upon breaking the key to reveal the identities of the toxic agents, it was found that all of the toxic samples in the study had been distinguished accurately from non-toxic controls that were included among the blind samples. Furthermore, it was revealed that most of the toxic agents detected had never before been tested or calibrated against chromatophores, demonstrating that detection can be achieved under naive conditions that have not been optimized for the analysis of any particular toxic agent. Finally, by organizing the results into categories of pigment responses, a binary classification tree was generated that distinguished each toxic agent as having a distinct response pattern from the others. Thus, chromatophore-based cytosensors can discover toxicity in the absence of prior knowledge of the agent in question, and the categories of responses of the cells can be used to distinguish one toxic agent from another.