Update on imaging of the discoid meniscus.

Discoid menisci represent a range of morphological meniscal variants, most commonly involving the lateral meniscus. Clinical presentation ranges from an asymptomatic incidental finding to snapping, pain, swelling and reduced range of knee movement. Symptomatic presentation of discoid menisci is usually due to meniscal tears and instability resulting from abnormal meniscal morphology and ultrastructure, with absent peri-meniscal ligamentous and meniscocapsular attachments characteristic of the Wrisberg sub-type. This article reviews the current classification systems of discoid menisci, gross morphological characteristics of each sub-type and ultrastructure. Clinical presentation, arthroscopic findings and indirect radiological diagnostic criteria are described, as are the MRI findings of normal and pathological discoid menisci. Current concepts of surgical management and outcomes of the discoid meniscus are also briefly discussed.

Connectivity in the cold: the comparative population genetics of vent-endemic fauna in the Scotia Sea, Southern Ocean.

We report the first comparative population genetics study for vent fauna in the Southern Ocean using cytochrome C oxidase I and microsatellite markers. Three species are examined: the kiwaid squat lobster, Kiwa tyleri, the peltospirid gastropod, Gigantopelta chessoia, and a lepetodrilid limpet, Lepetodrilus sp., collected from vent fields 440 km apart on the East Scotia Ridge (ESR) and from the Kemp Caldera on the South Sandwich Island Arc, ~95 km eastwards. We report no differentiation for all species across the ESR, consistent with panmixia or recent range expansions. A lack of differentiation is notable for Kiwa tyleri, which exhibits extremely abbreviated lecithotrophic larval development, suggestive of a very limited dispersal range. Larval lifespans may, however, be extended by low temperature-induced metabolic rate reduction in the Southern Ocean, muting the impact of dispersal strategy on patterns of population structure. COI diversity patterns suggest all species experienced demographic bottlenecks or selective sweeps in the past million years and possibly at different times. ESR and Kemp limpets are divergent, although with evidence of very recent ESR-Kemp immigration. Their divergence, possibility indicative of incipient speciation, along with the absence of the other two species at Kemp, may be the consequence of differing dispersal capabilities across a ~1000 m depth range and/or different selective regimes between the two areas. Estimates of historic and recent limpet gene flow between the ESR and Kemp are consistent with predominantly easterly currents and potentially therefore, cross-axis currents on the ESR, with biogeographic implications for the region.

Tibial cortical lesions: a multimodality pictorial review.

Shin pain is a common complaint, particularly in young and active patients, with a wide range of potential diagnoses and resulting implications. We review the natural history and multimodality imaging findings of the more common causes of cortically-based tibial lesions, as well as the rarer pathologies less frequently encountered in a general radiology department.

The biogeography of the yeti crabs (Kiwaidae) with notes on the phylogeny of the Chirostyloidea (Decapoda: Anomura).

The phylogeny of the superfamily Chirostyloidea (Decapoda: Anomura) has been poorly understood owing to limited taxon sampling and discordance between different genes. We present a nine-gene dataset across 15 chirostyloids, including all known yeti crabs (Kiwaidae), to improve the resolution of phylogenetic affinities within and between the different families, and to date key divergences using fossil calibrations. This study supports the monophyly of Chirostyloidea and, within this, a basal split between Eumunididae and a Kiwaidae-Chirostylidae clade. All three families originated in the Mid-Cretaceous, but extant kiwaids and most chirostylids radiated from the Eocene onwards. Within Kiwaidae, the basal split between the seep-endemic Kiwa puravida and a vent clade comprising Kiwa hirsuta and Kiwa spp. found on the East Scotia and Southwest Indian ridges is compatible with a hypothesized seep-to-vent evolutionary trajectory. A divergence date estimate of 13.4-25.9 Ma between the Pacific and non-Pacific lineages is consistent with Kiwaidae spreading into the Atlantic sector of the Southern Ocean via the newly opened Drake Passage. The recent radiation of Kiwaidae adds to the list of chemosynthetic fauna that appear to have diversified after the Palaeocene/Eocene Thermal Maximum, a period of possibly widespread anoxia/dysoxia in deep-sea basins.

Imaging of dysplasia epiphysealis hemimelica (Trevor's disease).

Dysplasia epiphysealis hemimelica (DEH; synonyms; Trevor's or Trevor Fairbank disease) is a rare developmental disorder of the skeleton characterized by asymmetric osteochondral overgrowth of the cartilage of a medial or lateral epiphysis or epiphyseal equivalent. Imaging plays an important role in the diagnosis and management of DEH and in assessing the need for biopsy to differentiate it from more sinister diseases. There is no recent comprehensive review of the imaging of DEH and the purpose of this article is to describe the modern radiological manifestations of DEH.

The biodiversity of the deep Southern Ocean benthos.

Our knowledge of the biodiversity of the Southern Ocean (SO) deep benthos is scarce. In this review, we describe the general biodiversity patterns of meio-, macro- and megafaunal taxa, based on historical and recent expeditions, and against the background of the geological events and phylogenetic relationships that have influenced the biodiversity and evolution of the investigated taxa. The relationship of the fauna to environmental parameters, such as water depth, sediment type, food availability and carbonate solubility, as well as species interrelationships, probably have shaped present-day biodiversity patterns as much as evolution. However, different taxa exhibit different large-scale biodiversity and biogeographic patterns. Moreover, there is rarely any clear relationship of biodiversity pattern with depth, latitude or environmental parameters, such as sediment composition or grain size. Similarities and differences between the SO biodiversity and biodiversity of global oceans are outlined. The high percentage (often more than 90%) of new species in almost all taxa, as well as the high degree of endemism of many groups, may reflect undersampling of the area, and it is likely to decrease as more information is gathered about SO deep-sea biodiversity by future expeditions. Indeed, among certain taxa such as the Foraminifera, close links at the species level are already apparent between deep Weddell Sea faunas and those from similar depths in the North Atlantic and Arctic. With regard to the vertical zonation from the shelf edge into deep water, biodiversity patterns among some taxa in the SO might differ from those in other deep-sea areas, due to the deep Antarctic shelf and the evolution of eurybathy in many species, as well as to deep-water production that can fuel the SO deep sea with freshly produced organic matter derived not only from phytoplankton, but also from ice algae.

The radiological appearances of thalassaemia.

The skeletal changes of untreated thalassaemia result from ineffective erythropoiesis and expansion of the bone marrow and affect every part of the skeleton. These changes include osteoporosis, growth retardation, platyspondyly and kyphosis. Erythropoiesis occurs at extra-medullary sites, most commonly resulting in a paraspinal mass but occasionally affecting organs containing pluripotential stem cells. Repeated transfusion unaccompanied by iron chelation causes haemosiderosis; iron is deposited at various sites causing functional impairment. Iron-chelation therapy with desferrioxamine (DFX) prevents haemosiderosis but causes a skeletal dysplasia predominantly affecting the rapidly growing long bones, in particular the distal ulna, and causing irregularity and sclerosis of the physeal-metaphyseal junction and splaying of the metaphysis. DFX also exacerbates the observed growth retardation. DFX-induced skeletal dysplasia may herald toxicity, which is associated with visual and auditory impairment. Therefore, careful balancing of the transfusion regimen and iron-chelation therapy is required. Magnetic resonance imaging (MRI) is the most sensitive technique for the detection of DFX-induced dysplasia.

Ovarian Development in the Class Holothuroidea: a Reassessment of the "Tubule Recruitment Model".

The "tubule recruitment model" for the development of the holothurian gonad was proposed (a) to connect the stages of oogenesis with ovarian morphology in holothurians throughout the reproductive season and (b) to emphasize the potential for the holothurian ovary as a model system for cytological and biochemical study of echinoderm oogenesis. To reassess the evidence for this model, we have examined published accounts and unpublished observations on gonad development in holothurians from both temperate and tropical habitats, in shallow water and in the deep sea. A very limited number of species were found to conform to the predictions of the tubule recruitment model. The patterns of gonad development vary substantially in holothurians, even at the individual level, and with taxonomic position, geographical location, and habitat. The tubule recruitment model can be applied to only a small subset of holothurians, specifically those in the families Stichopodidae and Holothuriidae that have gonad morphology similar to that of Parastichopus californicus. However, the tubule recruitment model is invalid for many other aspidochirotes, and does not have wider applicability within the class Holothuroidea.

Development of a stress scale for mental health professionals.

This paper describes the development of the Mental Health Professionals Stress Scale (MHPSS): a self-report method of identifying sources of stress for mental health professionals. The 42-item scale, which includes seven subscales, was administered to 154 clinical psychologists and 111 mental health nurses. The MHPSS was found to have good internal consistency (alpha = .87 for clinical psychologists; alpha = .94 for mental health nurses). The preliminary evidence suggests that the concurrent validity of the MHPSS is good. The expected relationships between the scale and between the criterion measures--General Health Questionnaire, a symptom check list, job satisfaction, self-reported stress level and quality of social support--were demonstrated. The results also provide evidence for the discriminant validity of the subscales to measure different aspects of the stress experience. The MHPSS was shown to discriminate between two groups of health professionals who might be expected to differ in their sources of stress. For clinical psychologists the most important source of stress was 'professional self-doubt' whereas the major source of stress for mental health nurses was found to be the difficulty of handling potentially violent or difficult patients in the context of scarce staff resources. For both groups, however, 'home-work conflict' was the subscale most strongly and consistently associated with mental health outcome. It is concluded that the preliminary evidence regarding the utility of the MHPSS is encouraging, although further data are clearly needed.

Human sensitivity to temporal proximity: the role of spatial and temporal speed gradients.

Estimates of temporal proximity (sometimes called time-to-collision) from random-dot flow patterns are shown to be based upon retinal speed, rather than upon changes in dot density. Neither the spatial nor the temporal gradient of motion is essential to the task, but estimates can be made from either alone. Performance is unaffected by the addition of rotational motion, suggesting that observers are capable of extracting the radial component of motion, which contains all the relevant information, from complex stimuli.

Sources of stress and psychological well-being in high-dependency nursing.

The present study examined occupational stress in four areas of high-dependency nursing: theatres, liver/renal, haematology/oncology and elective surgery. A total of 60 nurses from one large NHS hospital completed questionnaires on sources and levels of stress, psychological well-being and ways of coping; interviews with a small sub-sample were carried out. The results indicated that the amount of stress experienced was similar across all four departments, but its sources varied. Theatre nurses experienced less stress through patients' death and dying. Other factors which influenced both the level and sources of stress included post-qualification training, number of children and partnership-status. Nurses with post-qualification training perceived higher levels of stress. Social support was found to influence psychological well-being. Nurses who were living with a partner or were married experienced fewer stress symptoms than those with no partner, and nurses with two children experienced significantly less stress through dealing with patients and relatives. Reactions to stress elicited a range of adaptive and maladaptive coping styles. Nurses sampled indicated universal support for the introduction of 'nurse-for-a-day' and management 'swap-overs' as practised in Boston, USA. This study recommends sending nurses on management and administration courses and stress-management programmes.

Stress and well-being in nurses: a comparison of the public and private sectors.

Nurses in the public and private sectors were compared with regard to occupational stress and its sources and self-reported health and well-being. While both groups reported similar high levels of stress experience, most noticeably arising from high work loads and the experience of death and dying, group differences did emerge from an examination of the sources of stress. Whereas N.H.S. nurses were more troubled by high work loads, private sector nurses reported uncertainty over treatment as a more frequent source of stress than did their N.H.S. counterparts. Levels of self-reported mental and physical health symptomatology did not differ between groups. Nevertheless, overall nursing stress scores and symptomatology were significantly correlated, and workload was the best independent predictor of health and well-being status.

Sources of stress and dissatisfaction among nurses in four hospital environments.

A study was designed to examine the hypothesis that occupational stress in nurses is a function of how they perceive their work environment. Sixty-five nurses on four mixed-sex wards were interviewed using a nursing stress and work environment scale. Demographic data including age, sex and nursing status were also collected. 'Work overload' and the 'death and dying' of patients were identified as the major sources of stress for all the nurses. In general, although there was little difference between the specialized and non-specialized groups of nurses in the degree of stress experienced, the work environments were found to be dissimilar. The reported level of dissatisfaction with their work environment combined with certain demographic characteristics were found significantly to predict the degree of stress experienced. These findings have implications for the organization of the ward and for the skills taught to nurses by which stress may be managed or alleviated.