Phylogenetic relationships amongst Chloromyxum Mingazzini, 1890 (Myxozoa: Myxosporea), and the description of six novel species from Australian elasmobranchs.

Six novel species of Chloromyxum Mingazzini, 1890 are described using a whole evidence approach combining morphometric and molecular data, together with features of their biology. Elasmobranchs were collected in Australian waters, from the Great Barrier Reef, Queensland, off Lizard and Heron Islands; from Moreton Bay, southeast Queensland; off Hobart, Tasmania; and from the Tamar River, Launceston, Tasmania. The novel species proposed here are: Chloromyxum hemiscyllii n.sp. from Hemiscyllium ocellatum; Chloromyxum kuhlii n.sp. from Neotrygon kuhlii; Chloromyxum lesteri n.sp. from Cephaloscyllium laticeps; Chloromyxum mingazzinii n.sp. from Pristiophorus nudipinnis; Chloromyxum myliobati n.sp. from Myliobatis australis; and Chloromyxum squali n.sp. from Squalus acanthias. A seventh species from Squalus acanthias is also reported but due to limited material is not formally described. Molecular phylogenetic analyses revealed that the genus Chloromyxum is polyphyletic, and species from elasmobranchs form a well-supported sister clade, with the type species Chloromyxum leydigi, to all other congeneric species clustering within the freshwater myxosporean clade. Morphological analysis showed that elasmobranch-infecting species are predominantly pyriform shaped, have clearly thickened spore apex and possess caudal filaments, compared to other Chloromyxum species which are generally spherical or subspherical, and lack caudal filaments. These morphological and phylogenetic data provide further support for the erection of new genera, but we conservatively consider the species described in this study and other elasmobranch-infecting Chloromyxum species as Chloromyxum sensu strictu, whilst the freshwater teleost infecting and amphibian infecting species we will assign as Chloromyxum sensu lato, until more comprehensive data are available.

First taxonomic description of multivalvulidan myxosporean parasites from elasmobranchs: Kudoa hemiscylli n.sp. and Kudoa carcharhini n.sp. (Myxosporea: Multivalvulidae).

Myxosporean parasites are significant parasites of fishes not only for their apparent high diversity but also for their potential impact on fish health and/or marketability. Regardless, our knowledge of most myxosporeans, especially those found in elasmobranch hosts, is superficial. A study of multivalvulidan diversity in a range of elasmobranchs from Queensland, Western Australia and the Northern Territory (Australia) was conducted to address this knowledge gap. Specimens were collected from a total of 3 orders, 9 families and 31 species of elasmobranchs. Myxosporean infections referable to the genus Kudoa were discovered in host muscle and characterized morphologically and genetically. Both small subunit (SSU) and large subunit (LSU) rDNA sequences were used in molecular phylogenetic analyses. Kudoa spp. infected 27 of the 31 species of elasmobranchs examined, representing new records of this parasite genus in 26, of the 27, host species. Kudoids were observed in all 3 orders, and 7 out of the 9 families of elasmobranchs investigated. This paper reports the first 2 multivalvulidan species to be formally described from elasmobranchs, Kudoa hemiscylli n.sp. characterized from Hemiscyllium ocellatum (and 8 other host species) and Kudoa carcharhini n. sp. characterized from Carcharhinus cautus (and 2 other host species). Phylogenetic analyses revealed that kudoids from elasmobranchs form a separate lineage to those of teleosts, but are anchored within the overall kudoid clade.

Medical students' attitudes towards abortion: a UK study.

BACKGROUND: There is little research into medical students' or doctors' attitudes to abortion, yet knowing this is important, as policy makers should be aware of the views held by professionals directly involved in abortion provision and changing views may have practical implications for the provision of abortion in the future. METHODS: We surveyed 300 medical students about their views on abortion, their beliefs about the status of the fetus and the rights of the mother, their attitude towards UK law and their willingness to be involved in abortion provision as qualified doctors. RESULTS: 62% of medical students were pro-choice, 33% pro-life and 7% undecided. Students' views correlated with gender, year of study and holding a religious belief. Their beliefs about abortion, the status of the fetus and the rights of women significantly correlated with their attitudes towards the UK law and their willingness to be involved in abortion provision. Students' willingness to be involved in abortion provision was related to their views on abortion, the extent of participation required, the circumstances of the pregnancy and the stage of pregnancy. CONCLUSIONS: The percentage of pro-choice students was lower than that found in research on general practitioners' attitudes to abortion. It is unclear whether this is because students become more pro-choice as they progress through their medical career or because there is genuinely a change in attitudes to abortion.

Broken bones and fractures - an audit of patients' perceptions.

INTRODUCTION: 'Have I got a fracture or a break doctor?' remains a commonly posed question in fracture clinics, suggesting that patients frequently feel a 'fracture' and a 'break' are two separate entities. This apparent misconception amongst fracture clinic patients may result in confusion and occasionally anger that doctors appear to have inconsistent views on the severity of their injury. Compliance and outcome of patient care can also be affected by poor communication. PATIENTS AND METHODS: Our questionnaire-based study was conducted in two stages. The initial objective was to establish whether this misconception surrounding the words 'fracture' and 'break' is commonly held amongst our out-patient trauma patients. The second stage of the audit was to determine whether a patient information leaflet on fractures/broken bones could help reduce this misconception. RESULTS: The preliminary audit involving 50 new patients attending our fracture clinic showed that 84% thought there was a difference between a 'fracture' and a 'break', with 68% believing a 'break' to be worse than a 'fracture'. Following the introduction of an information leaflet, a re-audit of 61 new patients took place. This time 67% felt there was a difference between a 'fracture' and a 'break', with 65% believing a 'break' to be worse than a 'fracture'. Only 21% had read the supplied information leaflet, and 69% of those still believed there was a difference between a 'fracture' and a 'break'. CONCLUSIONS: The majority of patients believed that there was a difference between a 'fracture' and a 'break'. Access to information leaflets did not appear to alter this misconception. Verbal communication and explanation may be more beneficial and practical than visual aids and leaflets in overcoming this problem.

Fixed or mobile bearing unicompartmental knee replacement? A comparative cohort study.

Unicompartmental knee replacement (UKR) for anteromedial osteoarthritis is a well-established technique. Numerous clinical outcome studies demonstrate good medium and long-term results. The aim of this prospective study was to compare the complications and short-term clinical outcome of the St. Georg Sled, a fixed bearing UKR, with the Oxford mobile bearing UKR. Outcome at 2 years was assessed using the Bristol knee score and the Oxford knee score; in addition, complications occurring since formal scoring at 2-year follow-up were recorded. A total of 47 Oxford UKRs and 57 St. Georg Sled UKRs were performed in 91 patients, none of whom were lost to follow-up. At 2 years, both outcome measures were better for the St. Georg Sled Group. The pain component of the Bristol knee score was significantly better for this group (p-value = 0.013). Three patients in the Oxford group had bearing dislocations and a further four patients required revision (mean time to revision 3.0 years). In the St. Georg Sled group, three patients required revisions (mean time to revision 3.4 years). These results demonstrate that in the short-term, the Oxford mobile bearing prosthesis has a higher re-operation rate and that the St. Georg Sled achieves better pain relief. The functional scores of the two groups were similar.

Maturational and maintenance effects of testosterone on terminal axon density and neuropeptide expression in the rat vas deferens.

Testosterone causes growth of many pelvic ganglion cells at puberty and their maintenance during adulthood. Here we have focused on two populations of pelvic ganglion cells that project to the rat vas deferens: noradrenergic neurons that innervate the smooth muscle and synthesize neuropeptide Y, and cholinergic neurons that primarily innervate the mucosa and contain vasoactive intestinal peptide. We have assessed the muscle innervation after pre- or postpubertal castration, using immunohistochemistry to determine axon density and radioimmunoassay to quantify levels of neuropeptides in tissue extracts. Our results show that androgen deprivation in each period causes substantial effects. Noradrenergic axons in the muscle increase in density after castration, partly due to organ size being smaller than age-matched controls. However, when corrected for target size, there is an overall decrease in total number of axons. This implies that androgen exposure at puberty has a direct effect on neurons to ensure that the adult pattern of innervation is attained, and that this is not simply by matching terminal field to target size. Similar effects of pre- and postpubertal castration imply that continued exposure to testosterone is necessary to maintain normal target innervation. Castration in both time periods increased the density of axons containing vasoactive intestinal peptide, however the effects of castration on the total number of these axons in the muscle were more variable. The concentration of vasoactive intestinal peptide increased substantially following either pre- or postpubertal castration although absolute amounts per vas deferens were decreased. Effects on neuropeptide Y concentration were less pronounced but the total amount per vas deferens was decreased after pre- or postpubertal castration. Our study shows that the action of testosterone (or a metabolite) on a pelvic ganglion cell soma is likely to reflect a change in its terminal field, but that these effects are not mediated simply by testosterone influencing the size of its target organ.

Sustaining olfaction at low salinities: evidence for a paracellular route of ion movement from the hemolymph to the sensillar lymph in the olfactory sensilla of the blue crab Callinectes sapidus.

Evidence reported previously suggests that in low-salinity conditions the integrity of the olfactory dendrites of the blue crab is sustained by a diffusion-generated ionic microenvironment within the aesthetascs. Diffusion of ions from the hemolymph to the sensillar lymph is proposed to maintain this microenvironment. In this study, using lanthanum as an electron-dense marker of extracellular fluid space, we find morphological evidence for paracellular continuity between the hemolymph and the sensillar lymph. Lanthanum penetrates extracellular fluid spaces within the aesthetascs when antennules are either perfused or bathed externally with solutions containing lanthanum nitrate. This was found in both freshwater- and seawater-acclimated animals. Evidence for ion diffusion from the aesthetascs was obtained using self-referencing, ion-selective microelectrodes. Both Ca2+ and K+ exhibit outwardly directed flux gradients associated with the aesthetasc tuft in low-salinity conditions. These findings are consistent with the concept that ion diffusion from the hemolymph to the sensillar lymph generates an ionic/osmotic microenvironment within the aesthetascs at low salinities.

Sustaining olfaction at low salinities: mapping ion flux associated with the olfactory sensilla of the blue crab Callinectes sapidus.

To test the hypothesis of a diffusion-generated, ionic/osmotic microenvironment within the olfactory sensilla (aesthetascs), flux gradients of Ca(2+) and K(+) associated with the external surfaces of these sensilla were spatially mapped using self-referencing, ion-selective microelectrodes. Blue crabs (Callinectes sapidus) acclimated to low-salinity conditions (15% sea water and fresh water) showed a net efflux of ions from the aesthetascs. The region of maximum flux associated with each aesthetasc conformed to that predicted from structural data and corresponded to the permeable region of the cuticle separating the olfactory dendrites from the external environment. Estimates of net flux from the entire tuft of aesthetascs for both Ca(2+) and K(+) fell within the predicted range on the basis of comparisons with (22)Na(+) flux measured previously and assuming a passive diffusion model of ion movement from the hemolymph to the sensillar lymph and, ultimately, to the external environment. The maximum concentrations of these ions measured deep within the tuft are discussed in the light of a potential across the aesthetascs that may limit ion efflux at low salinities.

Characterization of a phosphoinositide-mediated odor transduction pathway reveals plasma membrane localization of an inositol 1,4, 5-trisphosphate receptor in lobster olfactory receptor neurons.

The role of phosphoinositide signaling in olfactory transduction is still being resolved. Compelling functional evidence for the transduction of odor signals via phosphoinositide pathways in olfactory transduction comes from invertebrate olfactory systems, in particular lobster olfactory receptor neurons. We now provide molecular evidence for two components of the phosphoinositide signaling pathway in lobster olfactory receptor neurons, a G protein alpha subunit of the G(q) family and an inositol 1,4, 5-trisphosphate-gated channel or an inositol 1,4,5-trisphosphate (IP(3)) receptor. Both proteins localize to the site of olfactory transduction, the outer dendrite of the olfactory receptor neurons. Furthermore, the IP(3) receptor localizes to membranes in the ciliary transduction compartment of these cells at both the light microscopic and electron microscopic levels. Given the absence of intracellular organelles in the sub-micron diameter olfactory cilia, this finding indicates that the IP(3) receptor is associated with the plasma membrane and provides the first definitive evidence for plasma membrane localization of an IP(3)R in neurons. The association of the IP(3) receptor with the plasma membrane may be a novel mechanism for regulating intracellular cations in restricted cellular compartments of neurons.

Clinical and serological associations of anti-Ku antibody.

OBJECTIVE: To ascertain the clinical and serological associations of anti-Ku antibody. METHODS: Twenty-seven patients over a 7 year period (1987-1996) had anti-Ku antibody detected by counterimmunoelectrophoresis (CIEP). Nineteen patients were available for clinical review. Five patients were assessed by chart review. Serum was taken at review for repeat antibody analysis. Patients were assigned to diagnostic groups based on the American College of Rheumatology criteria. RESULTS: There were 22 women and 5 men. The duration of symptoms ranged from one year to 28 years. Nine patients fulfilled criteria for systemic lupus erythematosus (SLE), 4 scleroderma, 3 rheumatoid arthritis (RA), one discoid lupus, and 7 had an undifferentiated connective tissue disease. There was a low incidence of renal (2/24) and central nervous system involvement (1/24); 19/24 had Raynaud's phenomenon, 15/24 had inflammatory arthritis but only one had erosions on radiograph; 11/24 reported esophageal reflux symptoms. Three of 24 patients had myositis. All patients had anti-nuclear antibody using indirect immunofluorescence of > 640 titer with a speckled and nucleolar pattern. Anti-Ku antibody was detected on CIEP in 15/19 sera available for repeat testing. Three patients had anti-Ro antibody, 2 had anti-U1RNP antibody, one patient had anti-topoisomerase-1 and anti-Ro. CONCLUSION: Anti-Ku antibody is found in a wide variety of connective tissue syndromes. While several patients fulfilled diagnostic criteria for SLE, scleroderma, and RA, their clinical features were usually mild and did not form a distinctive clinical pattern. Common features associated with anti-Ku were Raynaud's phenomenon, arthralgia, skin thickening, and esophageal reflux. Few patients had associated autoantibody specificities found in SLE or scleroderma.

Latex allergy and latex sensitization in children and adolescents with meningomyelocele.

BACKGROUND: The high prevalence of clinical latex allergy and latex sensitization in children with meningomyelocele has been widely reported. It has also been noted that these same children have a higher than expected prevalence of atopic disease. It would be useful to have a safe, sensitive, and specific skin test to detect latex sensitivity and to know how well this test compares with available in vitro tests. It would likewise be helpful to know as fully as possible the characteristics of the individual and to evaluate the relative importance of factors suspected to contribute to clinical latex allergy and latex sensitization in this population. METHODS: A group of 116 children and adolescents 1 to 20 years of age were recruited for the study. An extensive history of latex allergy, atopic diseases, and surgical procedures was taken on all subjects. Each subject had either a latex skin test or an in vitro study for latex-specific IgE, and 67 subjects had both tests simultaneously. Eighty-five subjects had epicutaneous skin tests to a panel of environmental allergens. RESULTS: Overall, 25 of 116 (21.5%) subjects had a history of clinical latex allergy, and 51 of 116 (44%) were sensitized to latex. The sensitivity and specificity of skin tests for clinical latex allergy were slightly greater than for the in vitro test (100% vs 95.8% and 82.3% vs 68.9%, respectively). The positive predictive value and negative predictive value of skin testing for clinical latex allergy were also greater (67.6% vs 50% and 100% vs 98.1%, respectively). Age was found to be a significant variable for both latex allergy and latex sensitization. The number of surgical procedures undergone and the presence of positive skin test responses to environmental allergens were significantly correlated with latex sensitization but not with clinical allergy to latex. CONCLUSIONS: A sensitive, specific, and safe skin test for latex sensitivity appears superior to in vitro testing for latex allergy. Age, number of surgical procedures, and the presence of positive allergen skin test responses are significantly correlated with latex sensitization. Age alone is significantly correlated with clinical allergy to latex.

Androgen receptor immunoreactivity is present in primary sensory neurons of male rats.

We have examined the distribution of androgen receptor (AR) immunoreactivity in L6 and S1 dorsal root ganglia of male rats in order to determine whether the sensory component of reflex circuits is likely to be androgen-sensitive. Nuclear AR immunoreactivity was present in almost half of the neurons, but was decreased markedly by castration; after castration nuclear staining was absent and a few neurons showed dim cytoplasmic staining. Of the neurons possessing AR, half also contained calcitonin gene-related peptide (CGRP); in turn, > 80% of CGRP neurons contained AR. AR staining was present in both large and small CGRP neurons. This study shows that testosterone is likely to influence many sensory neurons and may therefore play an important role in modulating visceral and somatic reflexes.

Perinatal factors influencing survival in extremely low-birthweight infants.

The majority of deaths in normally formed infants occur in extremely low birth weight infants (< 1000 g). Survival rates for these infants have improved greatly but still vary from centre to centre and accurate local outcome figures are important for counselling parents and upholding standards of care. In the Rotunda Hospital, Dublin, over the 6 year period from 1 January 1990 to 31 December 1995, there were 34 474 deliveries over 500 g birthweight. One hundred and twenty-six of these were normally formed infants between 500 g and 999 g. Our objective was to analyse the factors influencing survival in these extremely low birthweight (ELBW) infants. Overall survival in the group was 63%. The most significant factors influencing survival to 28 days were gestation and birthweight. Survival increased from 33% at 24 weeks to 100% at 28 weeks' gestation and from 29% at 500-599 g to 87% at 900-999 g birthweight. Having controlled for gestational age, none of the following variables had a significant effect on survival: year of birth; gender; multiple pregnancy; 1-minute Apgar score; maternal age; parity; use of antenatal steroids; a history of antepartum haemorrhage, pre-eclamptic toxaemia or prolonged rupture of membranes. A 5-min Apgar score > 5 increased the chance of survival by 3.97 (95% CI: 1.46- 10). Both mode of delivery and incidence of chorioamnionitis had an influence on survival which varied according to the gestational age. A larger cohort of survivors would illustrate the effect of these variables more clearly.

The prevalence of chemical substance and alcohol abuse in an obstetric population in Dublin.

OBJECTIVE: To determine the prevalence of illicit drug abuse and alcohol use in an obstetric population based in an urban maternity hospital. SETTING: A collaborative study between the Rotunda Hospital, Dublin and the Irish National Drug Advisory & Treatment Centre. DESIGN: A prospective study consisting of anonymous, unlinked urine testing of 504 'first visit' antenatal patients and a separate group of 515 patients six weeks after delivery. METHODS & OUTCOME MEASURES: Toxicological screening using enzyme-linked immunoassay techniques, with all positive samples being reanalysed. Drug histories were taken and samples were tested for alcohol and six of the most commonly abused drugs. The pre- and postnatal prevalence of abuse was matched with demographic data. RESULTS: The prevalence of chemical substance misuse in the antenatal population was 2.8% and 5.6% in the postnatal population. Substances identified included benzodiazepines, cannabis, amphetamines, opiates and cocaine. Less than 2% of samples tested positive for alcohol. None of the women yielding positive samples had been pre-identified on the basis of history. A significant proportion of the women were in the high risk categories with regard to age and socio-economic status. CONCLUSION: The prevalence of drug misuse antenatally was nearly 3% and postnatally almost 6%. Substance abusers in pregnancy are more likely to be single, unemployed, and to have had a previous pregnancy.

Perireceptor mechanisms sustaining olfaction at low salinities: insight from the euryhaline blue crab Callinectes sapidus

As the blue crab Callinectes sapidus moves from sea water to fresh water, the 'exposed' chemosensory dendrites in the olfactory sensilla (aesthetascs) undergo changes in length that are positively correlated with environmental salinity. In this study, we demonstrate the following. (1) The responses of the olfactory receptor cells of freshwater-acclimated crabs are reduced relative to those of seawater-acclimated animals, but increase with a time course comparable to the increase in dendrite length when these crabs are transferred to sea water. (2) The olfactory response of seawater-acclimated crabs is lost and the chemosensory dendrites osmotically ablated if the aesthetascs are acutely exposed to low salinity. However, maintaining iso-osmotic conditions with mannitol preserves both the physiological response and the structural integrity of the dendrites. (3) The flux of [14C]thiocyanate and 22Na between the hemolymph and sensillar lymph of the aesthetascs indicates continuity between these fluid compartments. (4) There is a net efflux of Na+ from the hemolymph through the aesthetascs in freshwater-acclimated crabs, and measurements of electrical potential across the antennules suggest that this efflux largely derives from passive diffusion. (5) Dendrites in the aesthetascs of crabs acclimated to brackish water are intermediate in length between those of freshwater- and seawater-acclimated animals. Together, our findings suggest that, at low salinities, the efflux of Na+ (and probably other ions) from the hemolymph generates an ionic/osmotic microenvironment within the aesthetascs that sustains the structural and functional integrity of the olfactory dendrites. We propose that the length of these dendrites, and consequently the olfactory response, is constrained by the distance over which this microenvironment can be effectively maintained.