Factors influencing the persistence of enteropathogenic bacteria in wetland habitats and implications for water quality.

AIMS: To better understand the persistence dynamics of enteropathogenic bacteria in freshwater wetland habitats, we constructed lab-scale mesocosms planted with two different wetland plant species using a subsurface flow wetland design. Mesocosms were treated with either a high-quality or a poor-quality water source to examine the effects of water quality exposure and plant species on Escherichia coli, Salmonella spp. and Enterococcus spp. in the rhizoplane, rhizosphere and water of wetland habitats. METHODS AND RESULTS: Quantities of study micro-organisms were detected using real-time PCR in wetland mesocosms. A combination of molecular and culture-based methods was also used to enumerate these organisms from surface water and plant material at high, medium and poor water quality sites in the field. We found that all three enteropathogenic micro-organisms were influenced by microhabitat type and plant species. Organisms differed with respect to their predominant microhabitat and the extent of persistence associated with wetland plant species in the mesocosm study. Of the monitored pathogens, only E. coli was influenced by both water quality treatment and plant species. Salmonella spp. quantities in the rhizoplane consistently increased in all treatments over the course of the mesocosm experiment. CONCLUSIONS: Plant species selection appears to be an overlooked aspect of constructed wetland design with respect to the removal of enteropathogenic micro-organisms. Escherichia coli and Enterococcus concentrations in wetland outflow were significantly different between the two plant species tested, with Enterococcus concentrations being significantly higher in mesocosms planted with Phalaris arundinaceae and E. coli concentrations being higher in mesocosms planted with Veronica anagallis-aquatica. Furthermore, there is evidence that the rhizoplane is a significant reservoir for Salmonella spp. within wetland habitats. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first time that Salmonella spp. has been shown to proliferate under natural conditions within the rhizoplane. This will contribute to our understanding of wetland removal mechanisms for enteropathogenic bacteria. This study identifies the rhizoplane as a potentially important reservoir for human pathogenic micro-organisms and warrants additional study to establish whether this finding is applicable in non-wetland habitats.

Structure of oxidized bismuth nanoclusters.

Synchrotron X-ray diffraction has determined that beta-Bi(2)O(3) is the dominant oxide phase covering hexagonal bismuth nanoclusters produced in an inert gas aggregation source. Simulated Debye-Scherrer patterns have indicated that the oxide is 20 +/- 5 Angstroms thick on average, at the surface of 320 +/- 40 Angstroms diameter clusters. A Williamson-Hall analysis of the peak broadening was used to measure the non-uniform strain in clusters. The oxidized clusters were in -0.11 +/- 0.06% uniform compressive strain compared with other clusters without oxides detectable by X-ray diffraction which only have a small tensile uniform strain. High-resolution transmission electron microscopy (HRTEM) and multislice image simulations indicated a beta-Bi(2)O(3) thickness of 20-50 Angstroms. The HRTEM micrographs show the relative orientation between the oxide and the cluster core.

Relationships among three pathways for resource acquisition and their contribution to plant performance in the emergent aquatic Plant Lythrum salicaria (L.).

Three pathways for resource acquisition exist in the emergent aquatic plant, Lythrum salicaria (L.); a subterranean root system, a free-floating adventitious root system, and arbuscular mycorrhiza (AM) fungal hyphae colonizing subterranean roots. This study examined the relationship(s) among these pathways and their contribution to plant performance. If the free-floating adventitious root system and/or AM fungi contribute to plant growth in wetland habitats, we predicted that their absence would result in a significant reduction in plant performance. Furthermore, if a reduction in resource uptake, effected by an absence of free-floating adventitious roots and/or AM fungi, is compensated for by increased allocation to remaining pathway(s) for resource uptake, we predicted altered patterns of resource allocation among shoots and the remaining pathway(s) for resource uptake. Contrary to our predications, plants experiencing adventitious root removal and/or grown in the absence of AM fungi generally had greater biomass and total shoot height than controls. Similarly, while levels of AM colonization and subterranean root biomass displayed a treatment effect, the observed responses did not correspond with our predictions. This was also true for shoot : subterranean root dry weight ratios. Our results indicate that there is interaction among the 3 pathways for resource acquisition in L. salicaria and an effect on plant performance. The adaptive significance of these characteristics is unclear, highlighting the potential difficulties in extrapolating from terrestrial to aquatic plant species and among aquatic plant species with potentially different life history strategies.

The development of a preference-based measure of health in children with atopic dermatitis.

BACKGROUND: Outcomes of health care interventions can be measured in many different ways, but there has been growing interest in the role that quality-adjusted life-years (QALYs) can play in informing priorities in health care. While existing generic preference-based measures can be used to obtain QALYs, these measures may often be inappropriate for some conditions such as atopic dermatitis (AD). These measures are also usually developed for adults and may not capture the domains pertinent to children. OBJECTIVES: To develop a preference-based quality-of-life measure for use in children with AD. METHODS: Items generated from interviews conducted with parents of children with AD were used to form a health state classification system that gives 16 unique health states. One hundred and fifty members of the general population were interviewed to derive preference weights for these states, following the methods used in the valuation of the Health Utilities Index 2 (HUI 2). Each person valued 10 health states using the standard gamble technique. The primary analysis was the estimation of mean health state values for each of the 16 states. RESULTS: Mean values across the 16 health states range from 0.36 (SD = 0.36) for the worst state to 0.84 (SD = 0.19) on a scale from zero to one, where zero is for health states thought to be as bad as being dead and one is for perfect health. There was some support for the validity of the values from the fact that the values were logically consistent with the ordering of the health state classification system. CONCLUSIONS: These results show the perceived importance of the defined health states of childhood AD to the general population. The resultant health state classification and values can be used to calculate QALYs for use in assessing the cost-effectiveness of interventions for children with AD.

Phosphorus, arbuscular mycorrhizal fungi and performance of the wetland plant Lythrum salicaria L. under inundated conditions.

The role of arbuscular mycorrhizal (AM) fungi in aquatic and semi-aquatic environments is poorly understood, although they may play a significant role in the establishment and maintenance of wetland plant communities. We tested the hypothesis that AM fungi have little effect on plant response to phosphorus (P) supply in inundated soils as evidenced by an absence of increased plant performance in inoculated (AM+) versus non-inoculated (AM-) Lythrum salicaria plants grown under a range of P availabilities (0-40 mg/l P). We also assessed the relationship between P supply and levels of AM colonization under inundated conditions. The presence of AM fungi had no detectable benefit for any measures of plant performance (total shoot height, shoot dry weight, shoot fresh weight, root fresh weight, total root length or total root surface area). AM+ plants displayed reduced shoot height at 10 mg/l P. Overall, shoot fresh to dry weight ratios were higher in AM+ plants although the biological significance of this was not determined. AM colonization levels were significantly reduced at P concentrations of 5 mg/l and higher. The results support the hypothesis that AM fungi have little effect on plant response to P supply in inundated conditions and suggest that the AM association can become uncoupled at relatively high levels of P supply.

Imaging of plant-thorn synovitis.

We describe a case of plant-thorn synovitis of the elbow resulting from a thorn injury. This caused recurrent pain and swelling of the elbow over a 3-month period. A magnetic resonance imaging examination was initially requested to exclude septic arthritis, and demonstrated a joint effusion, synovitis, and a 2-cm linear opacity embedded in the synovium. Ultrasound was performed prior to surgery to confirm these findings and provide accurate localization of the thorn fragment, later removed at surgery. To our knowledge this is the first example of this condition that has been confirmed by radiological imaging prior to surgery.

CT imaging and three-dimensional reconstructions of shoulders with anterior glenohumeral instability.

Glenohumeral instability is a common occurrence following anterior dislocation of the shoulder joint, particularly in young men. The bony abnormalities encountered in patients with glenohumeral instability can be difficult to detect with conventional radiography, even with special views. The aim of our study was to evaluate the bony abnormalities associated with glenohumeral instability using CT imaging with 3-D reconstruction images. We scanned 11 patients with glenohumeral instability, one with bilateral symptoms; 10 were male, one female, and their ages ranged from 18-66 years. Contiguous 3 mm axial slices of the glenohumeral joint were taken at 2 mm intervals using a Siemens Somatom CT scanner. In the 12 shoulders imaged, we identified four main abnormalities. A humeral-head defect or Hill-Sachs deformity was seen in 83% cases, fractures of the anterior glenoid rim in 50%, periosteal new bone formation secondary to capsular stripping in 42%, and loose bone fragments in 25%. Manipulation of the 3-D images enabled the abnormalities to be well seen in all cases, giving a graphic visualization of the joint, and only two 3-D images were needed to demonstrate all the necessary information. We feel that CT is the imaging modality most likely to show all the bone abnormalities associated with glenohumeral instability. These bony changes may lead to the correct inference of soft tissue abnormalities making more invasive examinations such as arthrography unnecessary.

Is mammography of value in women with disseminated cancer of unknown origin?

Mammography is often requested to try to identify occult primary breast carcinoma in women with metastatic cancer of unknown primary site. This study aimed to investigate whether mammography is of use in these patients in identifying the breast as the origin of the metastatic disease. Thirty-one women with a working diagnosis of metastatic cancer underwent mammography in an attempt to determine the primary site. None of these women had a palpable breast mass. The site of presentation, pathological type of tumour, site of origin, and benefit of mammography and mammography-provoked biopsy were clarified for each patient. The patients were also followed up to determine survival. The commonest sites of presentation were lung (45%), lymph nodes (19%) and abdomen (16%). The primary sites of these cancers were identified with confidence in 27 patients (87%). The commonest known primary tumour sites were lung (45%), breast (16%) and ovary (16%). Abnormal mammograms were detected in four patients (13%), but three of these did not have breast cancer. In one, the site of origin remained indeterminate, as either breast or lung. Five (16%) had a confident diagnosis of breast carcinoma; all of these women had normal mammograms. We conclude that mammography in women presenting with metastatic disease from an unknown primary site is unhelpful and is not recommended. Furthermore, we could not demonstrate its value in women presenting with axillary lymphadenopathy.

Magnetic resonance imaging of elephantiasis neuromatosa.

We present the case of a 43-year-old man with neurofibromatosis type 1 who developed elephantiasis neuromatosa of his left leg. The gross limb enlargement was extremely disfiguring, and resulted in such severe disability that he was only able to walk a very short distance using crutches. Previous debulking procedures had resulted in massive blood loss, and prior to attempting further surgical intervention MRI studies were requested. Taking advantage of the excellent tissue characterisation and multiplanar imaging capabilities of MRI, we were able to assess the extent of soft tissue and osseous involvement. The use of recently developed MR angiographic sequences enabled us to non-invasively provide detailed images to assess the relationship of the lesions to the major vessels, as well as the vascular supply and angiographic features of the lesions themselves. This article describes our MRI-based findings, which precluded debulking surgery in this unusual manifestation of neurofibromatosis.

Bilateral fracture dislocation of the sacroiliac joint.

We present a rare case of a 27-year-old man sustaining a bilateral fracture dislocation of the sacroiliac joints without disruption of the anterior pelvis, following a fall from a height. Reconstructed images in the coronal plane and three-dimensional CT images were invaluable in the diagnosis and assessment of this injury.

Pseudomyxoma extraperitonei: a lethal complication of mucinous adenocarcinoma of the appendix.

We report the unusual case of a 56-yr-old man who presented with an appendix abscess. This abscess failed to respond to standard treatment, and recurred despite operative intervention. A colocutaneous fistula developed, which initially discharged frank pus, then began discharging mucus via two cutaneous sinuses. No evidence of malignancy was detected from either repeat curettings or a diagnostic laparotomy. One and a half years after the initial presentation, histologic examination finally revealed mucinous adenocarcinoma of the appendix. We postulate that this malignancy in a retrocecal appendix resulted in a mucocele, which ruptured into the retroperitoneal space and drained via cutaneous sinuses, so-called pseudomyxoma extraperitonei. The patient declined further surgical intervention, and despite initial control by radiotherapy, the tumor spread locally to involve the entire right lower quadrant of the abdomen. The patient eventually died 39 months after the initial presentation.

False aneurysm of a lumbar artery following vertebral biopsy.

Vertebral body biopsy is regarded as a simple and relatively safe technique, with a low complication rate. We report the case of an 80-year-old man who developed a false aneurysm of a lumbar artery following biopsy of the fourth lumbar vertebra.

Sciatic nerve palsy caused by haematoma from iliac bone graft donor site.

A 27-year-old woman developed a haematoma-related compressive neuropathy of the right sciatic nerve following the harvesting of a bone graft from the posterior aspect of the right iliac crest. The nerve was compressed in an enclosed compartment between the sciatic notch and the piriformis muscle, which is thought to be involved in the piriformis syndrome. The symptoms improved once the haematoma was evacuated, and this complication stresses the importance of adequate haemostasis of the area from which the bone graft is taken.

Iliolumbar hernia following bone grafting.

A 40-year-old man developed a lumbar hernia through an iliac bone graft donor site. The defect was repaired using an autologous bone graft reinforced by titanium mesh.

Aldosterone is secreted intermittently during pregnancy.

Saliva aldosterone concentration was measured in samples collected at hourly intervals from healthy pregnant women (approximately 26 and 36 weeks gestation) who were going about their normal daily activities, and from some women hospitalized for disorders of pregnancy. In the healthy women diurnal saliva aldosterone fluctuated considerably, the highest values being 2-22 times the lowest on a given day. Because of the known correlation between saliva and plasma aldosterone concentrations we believe that the fluctuating salivary level is indicative of fluctuating plasma levels and that this is due to the intermittent secretion of aldosterone. The rate of decline of saliva aldosterone from peak levels indicated a half life (t 1/2) of 72 (SD 31) min which was not significantly different from that in non-pregnant subjects. The temporal pattern of saliva aldosterone suggests an enhanced response of the zona glomerulosa to the factors that cause aldosterone secretion to fluctuate in non-pregnant subjects, rather than the development of a more potent stimulus to the zona glomerulosa during pregnancy. In addition to hour-to-hour variation there is also substantial day-to-day variation, so that estimation of aldosterone in a single sample of saliva or plasma is of little value during pregnancy. The mean diurnal aldosterone concentration can be estimated from five saliva samples so this measurement presents a convenient technique for the assessment of aldosterone status in pregnancy. In contrast to healthy pregnancy, a patient with pre-eclampsia at 39 weeks gestation showed no elevation of saliva aldosterone above non-pregnant levels at any time during the day.