Ionophore-based optical nanosensors incorporating hydrophobic carbon dots and a pH-sensitive quencher dye for sodium detection.

Nanosensors present a biological monitoring method that is biocompatible, reversible, and nano-scale, and they offer many advantages over traditional organic indicators. Typical ionophore-based nanosensors incorporate nile-blue derivative pH indicators but suffer from photobleaching while quantum dot alternatives pose a potential toxicity risk. In order to address this challenge, sodium selective nanosensors containing carbon dots and a pH-sensitive quencher molecule were developed based on an ion-exchange theory and a decoupled recognition element from the pH indicator. Carbon dots were synthesized and integrated into nanosensors containing a pH-indicator, an analyte-binding ligand (ionophore), and a charge-balancing additive. These nanosensors are ion-selective against potassium (selectivity coefficient of 0.4) and lithium (selectivity coefficient of 0.9). Reversible nanosensor response to sodium is also demonstrated. The carbon dot nanosensors are resistant to changes in optical properties for at least 12 h and display stable selectivity to physiologically-relevant sodium (alpha = 0.5 of 200 mM NaCl) for a minimum of 6 days.

Prevalence of Cryptosporidium spp. in asymptomatic small ruminants in Grenada, West Indies.

Cryptosporidium spp. is a protozoan parasite that causes enteric infection in a wide range of hosts, including livestock and humans. The aim of this cross-sectional study was to estimate the prevalence of Cryptosporidium spp. in small ruminants in Grenada, West Indies. Fecal samples were collected from 100 sheep and 202 goats from 32 farms. The fecal samples were tested using an Enzyme-linked immunosorbent assay (ELISA) for qualitative detection of antigens in feces (Diagnostic Automation Inc., USA). The overall prevalence of Cryptosporidium spp. was 19.5% [95% confidence interval (CI): 15.4% to 24.4%] in both sheep and goats. The prevalence of Cryptosporidium spp. in sheep and goats was 14% (95% CI: 8.4% to 22.3%) and 22.3% (95% CI: 17.1% to 28.5%), respectively. There was no significant difference in the prevalence of Cryptosporidium spp. infection between sheep and goats (p = .42, Fisher's exact test) in Grenada. Of the 32 farms visited, 19 (59.4%) had at least one Cryptosporidium spp. positive animal.

Paranodal pathology in Tangier disease with remitting-relapsing multifocal neuropathy.

Pathological studies of a sural nerve biopsy in a man with Tangier disease presenting as a remitting-relapsing multifocal neuropathy showed abnormalities in the paranodal regions, including lipid deposition (65%) and redundant myelin foldings, with various degrees of myelin splitting and vesiculation (43%) forming small tomacula and abnormal myelin terminal loops (4%). The internodal regions were normal in the majority of myelinated fibres. Abnormal lipid storage was also present in the Schwann cells of the majority of unmyelinated fibres (67%). The evidence suggests that the noncompacted myelin region of the paranode is a preferential site for lipid storage in the myelinated Schwann cell, and that the space-occupying effects of the cholesterol esters leads to paranodal malfunction and tomacula formation as the pathological basis for the multifocal relapsing-remitting clinical course.

Effects of metal mining effluent on Atlantic salmon (Salmo salar) and slimy sculpin (Cottus cognatus): using artificial streams to assess existing effects and predict future consequences.

In the summer of 2000, the effects of metal mine discharge on fish growth and exercise performance were assessed at a Zn-Pb-Cu mine in New Brunswick, Canada. Juvenile Atlantic salmon (Salmo salar) were exposed to 0%, 20%, and 80% treated metal mine effluent in a mobile, fish-only artificial stream system. Fish were fed commercial salmon pellets throughout the study. Young-of-the-year slimy sculpins (Cottus cognatus) were exposed to the same treatments in a multitrophic level, modular artificial stream system or mesocosm, in which the fish were dependent on seeded algae and invertebrates for nutrition. Treatment concentrations were chosen to represent existing discharge dilutions (80%) and a scenario of reduced effluent discharge (20%) as predicted upon mine closure (scheduled for 2008). Al, Ba, B, Fe, Mn, Sr, Tl, Ti, and Zn increased in a concentration-dependent fashion across the three treatments. Salmon body burdens of Ba, Cd, Li, Cu, Mn, Se, Sr, and Zn were increased in the 80% treatment, while Tl increased across all treatment levels. Mortalities and depressions in growth in both fish species paralleled treatment concentrations (80%>20%>0%). Salmon liver weight was significantly greater in fish exposed to 20% and 80% effluent in a concentration-dependent fashion. Exercise performance in fish, as assessed by the ability to recover from forced exercise, showed little effect of treatment. The contamination of the receiving environment by mine discharges has led to loss of fish, making it impossible to study the system in situ. However, the use of the artificial stream systems enabled us to assess effects of present conditions on fish, as well as the potential impacts of mine reclamation. The 20% discharge predicted following mine reclamation is potentially favourable for the reinstitution of native fishes into the system.

Medicine taking decisions: schizophrenia in comparison to asthma and epilepsy.

This paper outlines a recent PhD study that explored factors underpinning decisions of people with schizophrenia regarding neuroleptic medicine taking. Relevant studies tend to be within the world view of psychiatry, resting on traditional concepts of compliance and insight. These studies examined schizophrenia outwith the context of other illnesses taking a snap shot view of medicine taking decision making, thus de-emphasizing its process. The chosen method of grounded theory (Glaser and Strauss 1967) overcomes these deficiencies. Stage 1 data arose from patient interviews, patients with asthma, epilepsy and schizophrenia contributed (n = 45), carers also sometimes contributed (n = 11), all three conditions being episodic disorders vulnerable to environmental stressors. Stage 2 develops from stage 1, mental health workers involved in the care of people with schizophrenia were interviewed, plus one asthma specialist and one epilepsy specialist (n = 16). Their views were compared to perspectives arising from the patient interviews and were included in the data, out of which an explanatory typology emerged. The three parts of the typology comprise the study's major categories and are labelled as: direct-reactive, deferential-compliant, and active discerning and optimizing. Active discerning and optimizing consists of two stages; experimental-reflective and consolidation. The core category of responsive resolution contains themes which run through all major categories.

A novel method for correlating internal and external structure of individual myelinated nerve fibres.

A new method is described that enables longitudinal and cross sections of an individual nerve fibre to be cut at multiple specified sites along the fibre by the use of a unique marker system. In this way the internal structure of the fibre can be correlated with the external appearance. Individual myelinated nerve fibres are teased apart in epoxy resin and mounted onto a carbon-coated slide, and after orientation and marking of specific sites of interest are snap frozen to liberate the orientated and marked fibres for embedding on the surface of an epoxy resin block for subsequent longitudinal or transverse sectioning. This method is particularly useful for the correlative study of the myelin-axon relationships.

Angiocentric T-cell lymphoma associated with human T-cell lymphotropic virus type I infection.

We describe two patients who presented with vasculitic, ulcerative skin lesions that had the histologic features of lymphomatoid granulomatosis or angiocentric T-cell lymphoma. These patients were found to have antibodies to human T-cell lymphotropic virus type I.

Diffuse geographic distribution of herbicides in northern prairie wetlands.

The concentrations of herbicides in water from wetlands on landscapes where herbicides are not used should be less than on farms with moderate (conventional farms) and intense (minimum-till farms) herbicide use. In general, this hypothesis was not supported for wetlands situated in the Boreal Plains Ecozone of central Saskatchewan, Canada. The overall detection frequency of 10 commonly used herbicides was not significantly different among wildlife habitat with no pesticide use (44.4%), farms with no pesticide use (51.6%), conventional farms (54.9%), and minimum-till farms (56.5%, chi 2 = 5.64, p = 0.13). The herbicides (4-chloro-2-methylphenoxy) acetic acid (MCPA), 2,4-dichlorophenoxyacetic acid (2,4-D), bromoxynil, dicamba, mecoprop, and diclorprop accounted for 87% of all detections. In general, detection frequencies and concentrations of individual herbicides were similar on all land-use types. For example, the mean concentration of 2,4-D in water on the four land types ranged from 0.12 +/- 0.104 to 0.26 +/- 0.465 microgram/L, and MCPA ranged from 0.08 +/- 0.078 to 0.19 +/- 0.166 microgram/L. However, in the year of application, mean concentrations of MCPA and bromoxynil, but not 2,4-D, were significantly higher by about twofold in wetlands situated in fields where these herbicides were applied compared with all other wetlands. We propose that many agricultural pesticides are rapidly lost to the atmosphere at the time of application by processes such as volatilization from soil and plant evapotranspiration. Then, the herbicides used throughout the region may be directly absorbed to the surface of wetlands from the atmosphere, or they become entrained in local convective clouds, and are redistributed by rainfall in a relatively homogenous mixture over the agricultural landscape. The low levels of individual herbicides we found in most of the wetland waters would not cause chronic effects to aquatic biota.

DNA from urine sediment or buccal cells can be used for blood group molecular genotyping.

Accurate blood group antigen typing of red blood cells with a positive direct antiglobulin test or from a recently transfused patient has been a long-standing problem. To overcome this problem, we evaluated the feasibility of using somatic cells as a source of DNA for molecular genotyping. Two sources of cells that could be obtained by noninvasive procedures were chosen for analysis: urine samples, which were already available in the clinical laboratory, and buccal epithelial cells collected with cotton wool swabs. DNA, prepared using a commercial kit, was subjected to polymerase chain reaction amplification and followed by digestion with the appropriate restriction enzyme. Genotyping was performed for three alleles encoded by polymorphic genes on three different chromosomes, namely KEL1/KEL2, JKA/JKB, and FYA/FYB. Genotyping results were compared to the results of typing performed on red blood cells using standard hemagglutination techniques. Results given by samples freshly collected from volunteer donors were concordant. Although results obtained with samples collected from hospital patients were initially not in agreement with the phenotyping results, adjustments to the test protocol resulted in concordance. DNA from blood, urine sediment, or buccal cells can be used for blood group molecular genotyping.

Accuracy of sampling methods in morphometric studies of human sural nerves.

The aim of this study was to ascertain the minimum sample required to accurately measure the total number of myelinated fibres, mean myelinated fibre density (MFD), myelinated fibre diameter (Ds) and axonal diameter (Da) in morphometric studies of sural nerve biopsies. Measurements were obtained by sampling a single fascicle or systematic sampling of up to 50% of the total transverse fascicular area of two control and eighteen pathological sural nerves showing varying degrees of demyelination and axonal degeneration. MFD and fibre size were heterogeneous between fascicles in both control and pathological sural nerves, and morphometric results from one fascicle and systematic sampling of up to 50% of the total transverse fascicular area did not accurately represent the whole myelinated fibre population in the sural nerve. For accurate morphometric data it is necessary to quantitate all the myelinated fibres in the sural nerve.

Nursing models and the idea of nursing.

The Wittgensteinian idea of family resemblances and meaning is explained. The idea of nursing is examined from this standpoint as are the knowledge claims of several influential nursing models. It is argued that the task of building a general model of nursing is theoretically impossible. The political and educational implications of the above argument are developed.

Social epistemology, gender and nursing theory.

A major claim for nursing theory is that it contributes to the generation of a body of nursing knowledge that will be important in the definition of nursing's boundaries. It is argued here that the epistemic authority of nursing knowledge is determined by factors such as the gender structure of nursing. This means the knowledge products of nursing will be given low epistemic status by both nurses and non-nurses. The implications of this argument, in terms of professionalisation and the project to develop nursing theory, are examined.

Benner and expertise in nursing: a critique.

This paper examines the work of Benner (From Novice to Expert: Excellence and Power in Clinical Nursing Practice. Addison-Wesley, Menlo Park, CA, 1984) on expertise in clinical nursing. The philosophical foundations of her work are explained as well as the work located within the wider context of the use of Heideggerian philosophy. Various criticisms of her study are developed in relationship to her methodology and her interpretation of nursing. It is argued that she represents a retreat into tradition and authority in nursing.

Long-term illness and patterns of medicine taking: are people with schizophrenia a unique group?

Patients with schizophrenia relapse because of inadequate levels of medicine taking. Therefore, it seems logical to learn about the factors underpinning their medicine-taking decisions. Further research is urgently needed to explore this area and thereby to refine models of practice, to promote therapeutic interactions with medicine. Existing research tends to share three common deficits. * It is grounded in the worldview of the psychiatrist not the patient. * It studies the influence of symptoms on compliance behaviour in isolation from other potential variables. * It overlooks the potential influence of the chronicity experience in general by examining schizophrenia outwith the context of other enduring illnesses. Overall these deficits may combine to distort the influence of schizophrenic symptoms on medicine decision making and justify a coercive rather than an empowering approach. A pernicious self-fulfilling spiral may be contributing to the problem of relapse in schizophrenia. Potentially the mental health nurse has a role in addressing this problem.

Understanding the psychosocial aspects of HIV / AIDS prevention for northern Thai single adolescent migratory women workers.

PIP: This study describes formative research about sex, sexuality, and sexual relationships of northern Thai single female migratory laborers. Methodologies included focus group discussions, observation, and in-depth individual interviews. Findings revealed that these women were sexually active, although the actual number of girls who were or had been sexually active could not be determined. It was also found that serial partners were much common than multiple partner relationships. And that these young women did not practice safe sex which can be considered as a potential social consequences of negotiating safe sex often outweigh health consequences. Furthermore, respondents reported that condoms were "men's business" and that there are irreconcilable social costs if a single woman talks about condoms or AIDS. From these findings, it is suggested that these young women and girls, regardless of their occupation or marital status or age, need HIV/AIDS education. Condoms need to be brought out of the disease spectrum and into the family planning and contraceptive spectrum. Educational interventions and material should address young people's emotional and relational needs including their desire to be modern and acceptable to peers.^ieng

The effect of neuraxial steroids on weight and bone mass density: a prospective evaluation.

The deleterious effects of corticosteroids utilized in neural blockade are a commonly discussed and contentious issue. Corticosteroids are considered to have widespread effects on almost all body systems, with suppression of the release of corticotropin (ACTH) from the pituitary suppressing the secretion of endogenous corticosteroids, thus producing a secondary adrenocortical insufficiency. Even though a multitude of complications of neuraxial steroids have been popularized, the more practical complications of corticosteroid administration are twofold - those resulting from withdrawal and those resulting from continued use of large doses. These mainly include suppression of the pituitary-adrenal axis, weight gain, osteopenia, osteoporosis, and a variety of other minor complications. This prospective evaluation was undertaken to evaluate the effect of corticosteroids and the dose relationship on weight gain, bone-mass density (BMD), and other deleterious effects of steroids. The study population consisted of 204 patients; however, complete data were available on only 123 patients. These patients were divided into two groups, with group I receiving neural blockade without any steroids, and, Group II consisting of patients receiving neuraxial steroids. The results of serial determination of weight and BMD showed no significant change at any interval or at the end of 1 year in all 123 patients with or without steroid administration. In addition, this study also showed some improvement in BMD, as well as weight reduction indicating improvement in functional status. It is concluded that low-dose administration of neuraxial steroids is safe in patients suffering with chronic pain who have failed to respond to conservative modalities of treatment with a favorable risk-benefit ratio. This study also showed no deleterious effect on weight or BMD.

Provocative discography in low back pain patients with or without somatization disorder: a randomized prospective evaluation.

Recent reports of provocative discography not only instill confusion, but also create numerous questions about its value in evaluating low back pain. It was reported that provocative discography produced pain in patients who were not suffering with low back pain but suffering with somatization disorder and depression. This study was designed to evaluate 50 randomly assigned patients, with 25 patients in Group I without somatization disorder and 25 patients in Group II with diagnosis of somatization disorder. In addition, depression, generalized anxiety disorder and combinations thereof were also evaluated. All patients underwent discography, investigating two to three discs in each patient. All studies included a control level with a disc that did not produce the patient's pain upon injection of contrast medium. Provocation with exact pain reproduction concordant with the symptom complex upon injection of contrast into the disc was considered positive. Any other response, with or without pain, was considered negative. Results showed positive provocative discography in 46% of the patients in the somatization group compared to 54% in the non-somatization group; in 46% of patients with depression compared to 54% of patients without depression; in 15 of 30 patients with generalized anxiety disorder; in 11 of 20 patients without generalized anxiety disorder; and in 42% of patients with combined somatization and depression, with negative discography in 58% of the patients. It is concluded that provocative discography provides similar results in patients with or without somatization, with or without depression, with somatization but with or without depression or with other combinations of the psychological triad of somatization disorder, depression, and generalized anxiety disorder.

Evaluation of the relative contributions of various structures in chronic low back pain.

An attempt was made to determine the relative contribution of various structures to chronic low back pain, including facet joint(s), disc(s), and sacroiliac joint(s) in a prospective evaluation. Precision diagnostic blocks, including disc injections, facet joint blocks, and sacroiliac joint injections, are frequently used. In contrast, selective nerve root blocks or transforaminal epidural injections are used occasionally to evaluate persistent or recurrent low back pain in patients without appropriate radiologic or neurophysiologic diagnosis. One hundred and twenty patients with a chief complaint of low back pain were evaluated with precision diagnostic injections, which included medial branch blocks, provocative discography and sacroiliac joint injections. In 40% (95% CL, 31%, 49%), of the patients, facet joint pain was diagnosed; and in 26% (95% CL, 18%, 34%) of the patients discogenic pain was diagnosed; and 2% of the patients were diagnosed with sacroiliac joint pain.

Influence of psychological factors on the ability to diagnose chronic low back pain of facet joint origin.

This study was designed to determine the prevalence of lumbar facet joint pain in patients suffering with or without somatization disorder. The study was performed using comparative local anesthetic blocks. One hundred consecutive patients with chronic low back pain, with or without somatization, were evaluated. The results showed that, among patients suffering with chronic low back pain, 44% of the patients without somatization and 38% of the patients with somatization were positive for facet joint pain. The diagnosis of facet joint pain was not influenced by the presence or absence of somatization disorder. The evaluation also was extended to depression, generalized anxiety disorder and combinations with or without somatization thereof which showed no significant differences in the prevalence of facet joint pain. The results of this study demonstrated that the facet joint was a source of pain in chronic low back pain patients in 44% of the patients without somatization and 38% of the patients with somatization. This study also showed that there was no correlation between the presence or absence of facet joint pain and the presence or absence of somatization disorder or any other psychological condition or combination thereof.

Effectiveness of percutaneous adhesiolysis with hypertonic saline neurolysis in refractory spinal stenosis.

The increasing proportion of elderly patients, coupled with increasing longevity, causes the problem of lumbosacral pain secondary to spinal stenosis of the lumbar spine to be an important issue. Symptoms of spinal stenosis are caused by entrapment and compression of intraspinal vascular and nervous structures; which may lead to inactivity, loss of productivity, and potential loss of independence, particularly in the elderly. Surgical decompression is considered as the natural treatment. However, the results of surgical treatments have been mixed. Results of conservative treatment are also not encouraging. While the effectiveness of caudal epidural blocks for lumbar canal stenosis was positive, the effectiveness of interlaminar epidural steroid injections showed no beneficial effects on symptomatology of spinal stenosis. Percutaneous epidural adhesiolysis with hypertonic saline neurolysis has been studied in patients with refractory low back pain secondary to post lumbar laminectomy syndrome, as well as spinal stenosis. The specific role of adhesiolysis and hypertonic saline neurolysis in the management of refractory low back and lower extremity pain secondary to spinal stenosis has not been studied. This retrospective evaluation included 18 patients derived from a total sample of 239 patients undergoing adhesiolysis and hypertonic saline neurolysis over a period of 3 years. The results showed significant improvement with reduction of pain; with improvement of physical health, mental health, and functional status. Improvement in psychological status was also noted, with decrease in narcotic intake. Epidural adhesiolysis with hypertonic saline neurolysis is a safe and probably effective modality of treatment in managing symptomatic moderate to severe lumbar spinal canal stenosis.