bluuebunny/crossref_metadata_2025 huggingface dataset:
A review of fish swimming mechanics and behaviour in altered flows
Authors: Liao James C
Published: May 2007

Fishes suspended in water are subject to the complex nature of three-dimensional flows. Often, these flows are the result of abiotic and biotic sources that alter otherwise uniform flows, which then have the potential to perturb the swimming motions of fishes. The goal of this review is to highlight key studies that have contributed to a mechanistic and behavioural understanding of how perturbing flows affect fish. Most of our understanding of fish behaviour in turbulence comes from observations of natural conditions in the field and laboratory studies employing controlled perturbations, such as vortices generated in the wake behind simple geometric objects. Laboratory studies have employed motion analysis, flow visualization, electromyography, respirometry and sensory deprecation techniques to evaluate the mechanisms and physiological costs of swimming in altered flows. Studies show that flows which display chaotic and wide fluctuations in velocity can repel fishes, while flows that have a component of predictability can attract fishes. The ability to maintain stability in three-dimensional flows, either actively with powered movements or passively using the posture and intrinsic compliance of the body and fins, plays a large role in whether fish seek out or avoid turbulence. Fish in schools or current-swept habitats can benefit from altered flows using two distinct though not mutually exclusive mechanisms: flow refuging (exploiting regions of reduced flow relative to the earth frame of reference) and vortex capture (harnessing the energy of environmental vortices). Integrating how the physical environment affects organismal biomechanics with the more complex issue of behavioural choice requires consideration beyond simple body motions or metabolic costs. A fundamental link between these two ways of thinking about animal behaviour is how organisms sense and process information from the environment, which determines when locomotor behaviour is initiated and modulated. New data are presented here which show that behaviour changes in altered flows when either the lateral line or vision is blocked, showing that fish rely on multi-modal sensory inputs to negotiate complex flow environments. Integrating biomechanics and sensory biology to understand how fish swim in turbulent flow at the organismal level is necessary to better address population-level questions in the fields of fisheries management and ecology.
Thermal and digestive constraints to foraging behaviour in marine mammals
Authors: Rosen David A.S , Winship Arliss J , Hoopes Lisa A
Published: May 2007

While foraging models of terrestrial mammals are concerned primarily with optimizing time/energy budgets, models of foraging behaviour in marine mammals have been primarily concerned with physiological constraints. This has historically centred on calculations of aerobic dive limits. However, other physiological limits are key to forming foraging behaviour, including digestive limitations to food intake and thermoregulation. The ability of an animal to consume sufficient prey to meet its energy requirements is partly determined by its ability to acquire prey (limited by available foraging time, diving capabilities and thermoregulatory costs) and process that prey (limited by maximum digestion capacity and the time devoted to digestion). Failure to consume sufficient prey will have feedback effects on foraging, thermoregulation and digestive capacity through several interacting avenues. Energy deficits will be met through catabolism of tissues, principally the hypodermal lipid layer. Depletion of this blubber layer can affect both buoyancy and gait, increasing the costs and decreasing the efficiency of subsequent foraging attempts. Depletion of the insulative blubber layer may also increase thermoregulatory costs, which will decrease the foraging abilities through higher metabolic overheads. Thus, an energy deficit may lead to a downward spiral of increased tissue catabolism to pay for increased energy costs. Conversely, the heat generated through digestion and foraging activity may help to offset thermoregulatory costs. Finally, the circulatory demands of diving, thermoregulation and digestion may be mutually incompatible. This may force animals to alter time budgets to balance these exclusive demands. Analysis of these interacting processes will lead to a greater understanding of the physiological constraints within which the foraging behaviour must operate.
Thermal substitution and aerobic efficiency: measuring and predicting effects of heat balance on endotherm diving energetics
Authors: Lovvorn J.R
Published: May 2007

For diving endotherms, modelling costs of locomotion as a function of prey dispersion requires estimates of the costs of diving to different depths. One approach is to estimate the physical costs of locomotion (Pmech) with biomechanical models and to convert those estimates to chemical energy needs by an aerobic efficiency (η=Pmech/Vo2) based on oxygen consumption (Vo2) in captive animals. Variations inηwith temperature depend partly on thermal substitution, whereby heat from the inefficiency of exercising muscles or the heat increment of feeding (HIF) can substitute for thermogenesis. However, measurements of substitution have ranged from lack of detection to nearly complete use of exercise heat or HIF. This inconsistency may reflect (i) problems in methods of calculating substitution, (ii) confounding mechanisms of thermoregulatory control, or (iii) varying conditions that affect heat balance and allow substitution to be expressed. At present, understanding of how heat generation is regulated, and how heat is transported among tissues during exercise, digestion, thermal challenge and breath holding, is inadequate for predicting substitution and aerobic efficiencies without direct measurements for conditions of interest. Confirming that work rates during exercise are generally conserved, and identifying temperatures at those work rates below which shivering begins, may allow better prediction of aerobic efficiencies for ecological models.
Growth, Income Inequality, and Fiscal Policy: What Are the Relevant Trade‐offs?
Authors: GARCÍA‐PEÑALOSA CECILIA , TURNOVSKY STEPHEN J.
Published: May 2007

We develop an endogenous growth model with elastic labor supply, in which agents differ in their initial endowments of physical capital. In this context, the growth rate and the distribution of income are jointly determined. We then examine the distributional impact of different ways of financing an investment subsidy. Policies aimed at increasing the growth rate result in a more unequal distribution of pre‐tax income, consistent with the positive correlation between income inequality and growth observed in the recent empirical literature. However, there is no conflict between efficiency and equity if inequality is measured in terms of the distribution of welfare.
Technology Shocks and Monetary Policy: Revisiting the Fed's Performance
Authors: AVOUYI‐DOVI SANVI , MATHERON JULIEN
Published: May 2007

Would the U.S. economy's dynamic response to permanent technology shocks have been different from the actual responses if monetary authorities' systematic response to these shocks had been optimal? To answer this question, we characterize the dynamic effects of permanent technology shocks and the way in which U.S. monetary authorities reacted to these shocks over the sample 1955(1)–2002(4) using a structural VAR. A sticky price–sticky wage model is developed and estimated to reproduce these responses. We then formally compare these responses with the outcome of the optimal monetary policy.
Prudential Regulation and the “Credit Crunch”: Evidence from Japan
Authors: WATANABE WAKO
Published: May 2007

The underlying causes of sharp declines in bank lending during recessions in large developed economies, as exemplified by the U.S. in the early 1990s and Japan in the late 1990s, are still being debated due to the lack of any convincing identification strategy of the supply side capital–lending relationship from lending demand. Using within bank share of real estate lending in the late 1980s as an instrumental variable for bank capital, we find that Japanese banks cut back on their lending in response to a large loss of bank capital in fiscal year 1997.
Psychiatric and Behavioral Manifestations of Vascular Dementia
Authors: Stewart Jonathan T.
Published: May 2007

Vascular dementia (VaD) is the second most common cause of dementia, accounting for about 20% of all cases. Psychiatric and behavioral problems are at least as common in VaD as in Alzheimer's disease but are very different qualitatively. Patients with VaD, and especially those with small vessel disease, typically manifest symptoms related to damage to the frontal‐subcortical system of the brain, including loss of executive function (which is not generally detected with most conventional tests of cognitive function), loss of drive, and disinhibited behaviors. Patients with VaD also commonly develop treatable mood disorders, most commonly depression. Once the symptoms are recognized, the clinician is in an ideal position to manage them and to educate caregivers about their nature.
General Characteristics of Treatable, Reversible, and Untreatable Dementias
Authors: Lowenthal David T. , Paran Esther , Burgos Luis , Williams Leonard S.
Published: May 2007

The modification of cognitive function with age has been the focus of numerous studies. Most of the research has suggested that these changes, at least in the majority of individuals, occur only at a very advanced stage; however, those conditions that are treatable and potentially reversible are acute in onset and often associated with acute confusional states. Therefore, physicians should be aware of the possibility of reversible causes of cognitive change in their elderly patients, including certain medications responsible for memory loss and other organ system diseases. In addition, the authors stress that not all memory loss in geriatric patients is due to Alzheimer's disease and that when history and physical examination provide evidence of hypertension and magnetic resonance imaging provides evidence of leukoaraiosis, a diagnosis of vascular dementia should be considered.
A Review of the Association Between Congestive Heart Failure and Cognitive Impairment
Authors: Cohen Michael B. , Mather Paul J.
Published: May 2007

Heart failure is a growing epidemic with an estimated 5 million Americans suffering from this condition. Several clinical trials have demonstrated a high correlation between congestive heart failure (CHF) and cognitive impairment. The severity of cognitive impairment correlates positively with the degree of CHF. The underlying mechanism for cognitive impairment remains unclear but appears to be related to cerebral hypoperfusion and impaired cerebral reactivity with selective impairment of verbal memory and attention domains. Furthermore, cognitive dysfunction represents one aspect of frailty, a novel concept that encompasses a range of clinical conditions that results in functional impairment in patients with heart failure. In addition, frailty independently predicts mortality in CHF patients. Cognitive impairment is a common and predictable effect of CHF that contributes with social and behavioral problems to decreased compliance to prescribed therapy and increased hospital readmissions. A multidisciplinary approach is necessary to deal with the complexity of this clinical syndrome.
Loss‐of‐function JAK3 mutations in TMD and AMKL of Down syndrome
Authors: De Vita Serena , Mulligan Claire , McElwaine Suzanne , Dagna‐Bricarelli Franca , Spinelli Monica , Basso Giuseppe , Nizetic Dean , Groet Jürgen
Published: May 2007

Acquired mutations activating Janus kinase 3 (jak3) have been reported in Down syndrome (DS) and non‐DS patients with acute megakaryoblastic leukaemia (AMKL). This highlighted jak3‐activation as an important event in the pathogenesis of AMKL, and predicted inhibitors of jak3 as conceptual therapeutics for AMKL. Of 16 DS‐transient myeloproliferative disorder (TMD)/AMKL patients tested, seven showed JAK3 mutations. Three mutations deleted the kinase (JH1) domain, abolishing the main function of jak3. Another patient displayed a mutation identical to a previously reported inherited loss‐of‐function causing severe combined immunodeficiency. Our data suggest that both gain‐, and loss‐of function mutations of jak3 can be acquired in DS‐TMD/AMKL.
Identification of novel molecular prognostic markers for paediatric T‐cell acute lymphoblastic leukaemia
Authors: Gottardo Nicholas G. , Hoffmann Katrin , Beesley Alex H. , Freitas Joseph R. , Firth Martin J. , Perera Kanchana U. , De Klerk Nicolas H. , Baker David L. , Kees Ursula R.
Published: May 2007

In the last four decades the survival of patients with newly diagnosed childhood T‐cell acute lymphoblastic leukaemia (T‐ALL) has improved dramatically. In sharp contrast, relapsed T‐ALL continues to confer a dismal prognosis. We sought to determine if gene expression profiling could uncover a signature of outcome for children with T‐ALL. Using 12 patient specimens obtained before therapy started, we examined the gene expression profile by oligonucleotide microarrays. We identified three genes, CFLAR, NOTCH2 and BTG3, whose expression at the time of diagnosis accurately distinguished the patients according to disease outcome. These genes are involved in the regulation of apoptosis and cellular proliferation. The prognostic value of the three predictive genes was assessed in an independent cohort of 25 paediatric T‐ALL patients using quantitative real‐time reverse transcription polymerase chain reaction. Patients assigned to the adverse outcome group had a significantly higher cumulative incidence of relapse compared with patients assigned to the favourable outcome group (46% vs. 8%, P = 0·029). Five‐year overall survival was also significantly worse in the patients assigned to the adverse outcome group (P = 0·0039). The independent influence of the 3‐gene predictor was confirmed by multivariate analysis. Our study provides proof of principle that genome‐wide expression profiling can detect novel molecular prognostic markers in paediatric T‐ALL.
Loss of bHLH transcription factor E2A activity in primary effusion lymphoma confers resistance to apoptosis
Authors: Lietz Andreas , Janz Martin , Sigvardsson Mikael , Jundt Franziska , Dörken Bernd , Mathas Stephan
Published: May 2007

Similar to classical Hodgkin lymphoma (HL) tumour cells, primary effusion lymphoma (PEL) originates from mature B cells but displays a non‐B cell phenotype, the mechanisms and consequences of which are not yet understood. This study showed that PEL lacked DNA binding activity of the B cell‐determining transcription factors E2A, EBF and Pax5. PEL overexpressed the E2A antagonists ABF‐1 and Id2, which have been described to block the B‐cell differentiation program in classical HL. However, in contrast to HL cells, B lineage‐inappropriate genes were not similarly upregulated in PEL, and reconstitution of B cell‐specific E2A homodimer activity in PEL induced apoptosis. These data demonstrate that lineage infidelity in PEL is not as pronounced as in HL, and that the loss of the B cell‐specific transcription factor E2A in PEL is implicated in apoptosis protection.
Delayed redistribution of CD27, CD40 and CD80 positive B cells and the impaired in vitro immunoglobulin production in patients with non‐Hodgkin lymphoma after rituximab treatment as an adjuvant to autologous stem cell transplantation
Authors: Nishio Mitsufumi , Fujimoto Katsuya , Yamamoto Satoshi , Endo Tomoyuki , Sakai Toshiya , Obara Masato , Kumano Kohki , Yamaguchi Keisuke , Takeda Yukari , Goto Hideki , Sato Norihiro , Koizumi Kazuki , Mukai Masaya , Koike Takao
Published: May 2007

Recent studies have indicated that patients who received rituximab as an adjuvant to stem cell transplantation (SCT) demonstrated an increased risk of developing severe hypogammaglobulinaemia, which was found to be a result of delayed recovery of CD27 positive memory B cells and impaired isotype expression. It appears that rituximab influences both the quantity and quality of B‐cell redistribution. Precisely how the B‐cell repertoire regenerates after anti‐CD20‐mediated transient B‐cell depletion in patients with non‐Hodgkin lymphoma (NHL) remains to be elucidated. This study performed a phenotypical analysis of B cells in 17 NHL patients who received rituximab as an adjuvant to autologous SCT. The median period after final administration of rituximab was 36 months (range, 12–43 months). Surface antigen expression of CD27, CD40 and CD80 in NHL patients was statistically significantly different from healthy controls (n = 14). Moreover, B cells from NHL patients showed significantly impaired IgG and IgA production upon engagement of surface immunoglobulin receptors in the presence of interleukin (IL)‐2, IL‐10 and CD40 ligand in comparison with samples from healthy controls. The delayed recovery of memory B cells with an abnormal cell marker expression and function demonstrates that naive B cells may fail to differentiate into plasma cells, resulting in hypogammaglobulinaemia after autologous SCT and rituximab therapy.
The number of tumour‐infiltrating TIA‐1+ cytotoxic T cells but not FOXP3+ regulatory T cells predicts outcome in diffuse large B‐cell lymphoma
Authors: Hasselblom Sverker , Sigurdadottir Margret , Hansson Ulrika , Nilsson‐Ehle Herman , Ridell Börje , Andersson Per‐Ola
Published: May 2007

The prognostic significance of tumour‐infiltrating lymphocytes (TILs) in patients with diffuse large B‐cell lymphoma (DLBCL) remains controversial. Furthermore, the possible impact of regulatory T cells (Tregs) on survival in DLBCL is still unknown. We performed a retrospective study on the immunohistochemical expression of cytotoxic cells and Tregs, and their correlation with survival in 195 DLBCL patients. Patients with a small number of cytotoxic T‐cell intracytoplasmic antigen‐1 (TIA‐1)+ T cells (≤260 cells/mm2 tumour area; n = 52) had significantly better outcome than patients with a large number (>260 cells/mm2; n = 143); progression‐free survival (PFS) at 5 years was 67% vs. 50% (P = 0·03) and overall survival (OS) was 73% vs. 57% (P = 0·03). In multivariate analysis, the low TIA‐1+ group still had a better PFS (relative risk 0·75, 95% confidence interval 0·31–0·99; P = 0·05). The number of forkhead box protein 3 (FOXP3)+ Tregs had no influence on PFS (P = 0·89) or OS (P = 0·75). These results suggest that immunohistochemical analysis of cytotoxic T cells at time of diagnosis could provide additional prognostic information. The lack of correlation between the number of FOXP3+ cells and survival could possibly indicate that tumour‐infiltrating Tregs are of less clinical importance in DLBCL. However, these findings need to be explored in functional studies.
Impacts of a reduced thermohaline circulation on transport and growth of larvae and pelagic juveniles of Arcto‐Norwegian cod (Gadus morhua)
Authors: VIKEBØ F. B. , SUNDBY S. , ÅDLANDSVIK BJØRN , OTTERÅ O. H.
Published: May 2007

A reduction of the thermohaline circulation (THC) might have strong impact on Northeastern Atlantic fisheries. We address this potential challenge by studying the effects of THC changes on larval drift and development of Arcto‐Norwegian Cod (ANC, Gadus morhua), as several studies have shown that there is a close link between the abundance and individual size of cod at the 0‐group stage and the year class strength of the 3‐group fish. The approach taken is that of a modelling study supported by analysis of existing data on fish stocks and climate. A regional model (ROMS) is forced by a global climate model (Bergen Climate Model‐BCM) in which the river runoff to the Nordic Seas and the Arctic Oceans is increased by a factor three over the present day value, causing the THC to slow down. Although this increase in river runoff is extreme, the simulated response might be applicable in explaining and interpreting possible processes and feedback mechanisms of relevance for ANC. The impact of the anomalous circulation and ocean temperature on ANC in its habitat as simulated by ROMS is studied by using an individual‐based model to simulate growth of the larvae and pelagic juveniles along their simulated drift paths. The present description of a reduction in the THC by 35% results in: (1) a southward and westward shift in the distribution of cod year classes from the Barents Sea onto the narrow shelves of Norway and Spitsbergen, (2) a reduced individual growth of the pelagic juveniles, (3) an increasing number of larvae and pelagic juveniles advected towards the western parts of Spitsbergen, and possibly further into the Arctic Oceans where they are unable to survive.
Interannual variability in hatching period and early growth of juvenile walleye pollock, Theragra chalcogramma, in the Pacific coastal area of Hokkaido
Authors: NISHIMURA AKIRA , HAMATSU TOMONORI , SHIDA OSAMU , MIHARA IKUO , MUTOH TAKASHI
Published: May 2007

Juvenile walleye pollock of the Japanese Pacific population were collected from the Funka Bay [spawning ground; 16–64 mm fork length (FL)] in spring and the Doto area (nursery ground; 70–146 mm FL) in summer. Hatch dates were estimated by subtracting the number of otolith daily increments from sampling dates, and their early growth was back‐calculated using otolith radius–somatic length relationships. Interannual change of the hatching period was observed during 2000–02, and the peaks ranged from mid‐February in 2000 to early‐April in 2002. In 2000, when a strong year class occurred, early life history of the surviving juveniles could be characterized by early hatching and slower growth in the larval stage (<22 mm length). Higher growth rate in 2001 and 2002 did not always lead to good survival and recruitment success. Even though their growth was slow in 2000, the larvae hatched early in the season had larger body size on a given date than faster‐growing larvae hatched in later season in 2001 and 2002. Bigger individuals at a certain moment may have advantage for survival. The delay of hatching period may result in higher size‐selective mortality, and as a necessary consequence, back‐calculated growth in 2001 and 2002 could shift towards higher growth rate, although abundance of such a year class would be at the lower level. Variability in spawning period, early growth and their interaction might have a strong relation to larval survival through cumulative predation pressure or ontogenetic changes in food availability.
Abundance and microhabitats of freshwater sponges (Spongillidae) in a Danubean floodplain in Austria
Authors: DRÖSCHER IRIS , WARINGER JOHANN
Published: May 2007

1. This study examined the abundance and distribution of freshwater sponges (Spongillidae) at 32 sites in a floodplain on the Danube within the ‘Donau‐Auen’ National Park east of Vienna, Austria. Ranked from abundant to rare, the species inventory comprised Ephydatia fluviatilis, Spongilla lacustris, Ephydatia mülleri, Eunapius fragilis and Trochospongilla horrida.

2. The presence of hard substratum was essential for the growth of sponges. Timber stands near the water and drifting dead wood increased the abundance of E. fragilis, E. fluviatilis and E. mülleri, whereas stony substrata were important for S. lacustris. A small fraction of E. fluviatilis was collected from macrophytes (Phragmites).

3. Based on the area colonised, the abundance of S. lacustris, E. fragilis and E. fluviatilis was highest (94.2–100% of the total) in floodplain waters where hydrological connectivity with the Danube was low (0–6 days year−1), whereas E. mülleri and T. horrida made up 20.3–35.9% of the total at sites connected for up to 179 days year−1. Moreover, the area colonised by T. horrida at a current velocity >0.20 m s−1 was larger than in the remaining species. Sites with E. mülleri and T. horrida had a higher silicon concentration (0.9 mg L−1) than sites where the remaining three species were collected (0.4–0.6 mg L−1).

4. In most species, the length of macroscleres (the larger spicules) was positively correlated with conductivity and negatively with pH. With respect to aberrant macroscleres, hooks were observed most frequently, whereas the proportion of centrotylotes (ie with the one on more globular swellings along the spicule) was lowest.

5. Freshwater sponges have a great deal of potential as bioindicators and restoration measures that improve floodplain connectivity will favour rare species, such as E. mülleri and T. horrida, while impairing others (e.g. E. fragilis, S. lacustris and E. fluviatilis).
Autoantibody profile in the experimental model of scleroderma induced by type V human collagen
Authors: Callado Maria R. M. , Viana Vilma S. T. , Vendramini Margarete B. G. , Leon Elaine P. , Bueno Cleonice , Velosa Ana P. P. , Teodoro Walcy R. , Yoshinari Natalino H.
Published: May 2007

The aim of this study is to evaluate the humoral autoimmune response in the experimental model of systemic sclerosis (SSc) induced by human type V collagen (huCol V). New Zealand rabbits were immunized with huCol V in Freund's complete adjuvant (FCA) and boosted twice with 15 days intervals with huCol V in Freund's incomplete adjuvant. Control groups included animals injected only with FCA or bovine serum albumin. Bleeding was done at days 0, 30, 75 and 120. Tissue specimens were obtained for histopathological investigation. Serological analysis included detection of antibodies against huCol V and anti‐topoisomerase I (Anti‐Scl70) by enzyme‐linked immunosorbent assay, antinuclear antibodies (ANA) by indirect immunofluorescence, and rheumatoid factor (RF) by a latex agglutination test. Target antigens were characterized by immunoblot. Histological analysis revealed extracellular matrix remodeling with fibrosis and vasculitis. Anti‐Scl70 and ANA were detected as early as 30 days in all huCol V animals. The universal ANA staining pattern was Golgi‐like. This serum reactivity was not abolished by previous absorption with huCol V. Characterization of the target antigen by immunoblot revealed two major protein fractions of 175 000 and 220 000 MW. Similarly to ANA, there was a gradual increase of reactivity throughout the immunization and also it was not abolished by preincubation of serum samples with huCol V. RF testing was negative in hyperimmune sera. Conclusion: The production of autoantibodies, including anti‐Scl70, a serological marker for SSc associated with histopathological alterations, validates huCol V induced‐experimental model and brings out its potential for understanding the pathophysiology of SSc.
Pressure ulcer risk in long‐term units: prevalence and associated factors
Authors: Capon Alessandra , Pavoni Noemi , Mastromattei Antonio , Di Lallo Domenico
Published: May 2007

Title. Pressure ulcer risk in long‐term units: prevalence and associated factors

Aim.  This paper is a report of a study to assess pressure ulcer prevalence in a group of long‐term units and to describe the main factors associated both with risk for and presence of a pressure ulcer.

Background.  Despite being potentially preventable, pressure ulcers are highly frequent among institutionalized patients and are associated with increased morbidity and mortality.

Method.  A cross‐sectional study was carried out, involving 571 patients from 10 long‐term units in Rome, Italy. Healthcare staff in each unit evaluated pressure ulcer risk and collected clinical data while a single Registered Nurse assessed all patients to identify pressure ulcers. Univariate and multivariate analyses were performed for the two outcomes: condition at risk for pressure ulcers (Braden score ≤ 16) and pressure ulcer presence. The data were collected in February‐March 2005.

Findings.  The overall prevalence of pressure ulcers was 27%. Multivariate analysis showed a statistically significant positive association between high‐risk condition of pressure ulcer and previous stroke (OR = 1·96; 95% CI 1·30–2·96), previous trauma (OR = 1·83; 95% CI 1·12–2·99) and cognitive decline (OR associated with a 1 point Short Portable Mental State Questionnaire increase = 1·26; 95% CI 1·05–1·50). The model for pressure ulcer presence confirmed a statistically significant excess in patients with cardiovascular diseases (OR = 1·79; 95% CI 1·13–2·85), with high Activity of Daily Living scores (OR associated with a 1 point increase 1·38; 95% CI 1·03–1·84) and low Braden Scale scores (OR associated with a 1 point increase = 0·80; 95% CI 0·70–0·87). The risk of pressure ulcers according to number of full‐time nurses and auxiliary staff per 10 beds lower than five was marginally statistically significant (OR = 1·60; 95% CI 0·98–2·61).

Conclusion.  Further research is needed to validate our findings and further prospective research is needed to identify ways of preventing pressure ulcers. Our data on staffing suggest that organizational factors should be taken into account when exploring determinants of pressure ulcers.
Caring for a relative with dementia: family caregiver burden
Authors: Papastavrou Evridiki , Kalokerinou Athena , Papacostas Savvas S. , Tsangari Haritini , Sourtzi Panagiota
Published: May 2007

Title.  Caring for a relative with dementia: family caregiver burden

Aim.  This paper is a report of part of a study to investigate the burden experienced by families giving care to a relative with dementia, the consequences of care for the mental health of the primary caregiver and the strategies families use to cope with the care giving stressors.

Background.  The cost of caring for people with dementia is enormous, both monetary and psychological. Partners, relatives and friends who take care of patients experience emotional, physical and financial stress, and care giving demands are central to decisions on patient institutionalization.

Method.  A volunteer sample of 172 caregiver/care recipient dyads participated in the study in Cyprus in 2004–2005. All patients were suffering from probable Alzheimer's type dementia and were recruited from neurology clinics. Data were collected using the Memory and Behaviour Problem Checklist, Burden Interview, Center for Epidemiological Studies‐Depression scale and Ways of Coping Questionnaire.

Findings.  The results showed that 68·02% of caregivers were highly burdened and 65% exhibited depressive symptoms. Burden was related to patient psychopathology and caregiver sex, income and level of education. There was no statistically significant difference in level of burden or depression when patients lived in the community or in institutions. High scores in the burden scale were associated with use of emotional‐focused coping strategies, while less burdened relatives used more problem‐solving approaches to care‐giving demands.

Conclusion.  Caregivers, especially women, need individualized, specific training in how to understand and manage the behaviour of relatives with dementia and how to cope with their own feelings.
The development and validation of the On‐the‐job Learning Styles Questionnaire for the Nursing Profession
Authors: Berings Marjolein G.M.C. , Poell Rob F. , Simons P. Robert‐Jan , Van Veldhoven Marc J.P.M.
Published: May 2007

Title.  The development and validation of the On‐the‐job Learning Styles Questionnaire for the Nursing Profession

Aim.  This paper is a report of a study to develop and test the psychometric properties of the On‐the‐job Learning Style Questionnaire for the Nursing Profession.

Background.  Although numerous questionnaires measuring learning styles have been developed, none are suitable for working environments. Existing instruments do not meet the requirements for use in workplace settings and tend to ignore the influence of different learning situations.

Method.  The questionnaire was constructed using a situation–response design, measuring learning activities in different on‐the‐job learning situations. Content validity was ensured by basing the questionnaire on interview studies. The questionnaire was distributed to 912 Registered Nurses working in different departments of 13 general hospitals in the Netherlands at the end of 2005.

Findings.  The response rate was 41% (372 questionnaires). The internal factor structure of the questionnaire was partly based on the learning activities in which nurses participate and partly on the learning situation in which they are performed. The internal consistency was good. The situation–response design of the questionnaire demonstrated its added value. Construct validity was estimated using intercorrelations between the scales, and criterion validity was estimated based on the relationships of the scales with perceived professional competence.

Conclusion.  The On‐the‐job Learning Styles Questionnaire for the Nursing Profession is well suited to describing nurses’ learning styles in on‐the‐job settings and has satisfactory psychometric properties.
The impact of social factors on tuberculosis management
Authors: Craig G.M. , Booth H. , Story A. , Hayward A. , Hall J. , Goodburn A. , Zumla A.
Published: May 2007

Title. The impact of social factors on tuberculosis management

Aim. This paper is a report of a study to examine the impact of social factors on the management of tuberculosis including engagement with services, hospitalization and extended treatment.

Background. Rates of tuberculosis in major European cities have increased greatly in the last 10 years. The changing epidemiology of the disease, concentrated in marginalized groups, presents new challenges to the control of tuberculosis.

Methods. A prospective cohort study of 250 newly diagnosed tuberculosis patients was conducted in London between January 2003 and January 2005. Data were collected by means of a risk assessment tool and from medical records. Outcome measures included missed appointments, frequency and duration of hospitalization and length of treatment.

Results. The median age of the study sample was 33·82 (range 16·4–92·5) and 56·8% were male. Thirty‐two per cent were hostel/street homeless or temporarily sharing accommodation with friends or relatives. Thirty‐nine per cent were in receipt of welfare benefits and 13·2% had no income. Over a third anticipated difficulties taking their medicines and 30·3% had noone to remind them of this. Increased hospitalization was associated with hostel/street homelessness, drug or alcohol use and having noone to remind them to take their medicines (allP ≤ 0·01). Missed appointments were associated with drug/alcohol use and previous tuberculosis treatment. Extended treatment was also associated with drug/alcohol use; previous tuberculosis treatment, drug resistance and those anticipating difficulties taking medication (allP ≤ 0·001).

Conclusions. The development of a social outreach model of care with an emphasis on prevention and support is an essential aspect of modern, international tuberculosis care.
Image: changing how women nurses think about themselves. Literature review
Authors: Fletcher Karen
Published: May 2007

Title. Image: changing how women nurses think about themselves. Literature review

Aim. This paper presents a review of the public and professional images of nursing in the literature and explores nurse image in the context of Strasen's self‐image model.

Background. Nurses have struggled since the 1800s with the problem of image. What is known about nurses’ image is from the perspective of others: the media, public or other healthcare professionals. Some hints of how nurses see themselves can be found in the literature that suggests how this image could be improved.

Method. A literature review for all dates up to 2006 was undertaken using PubMed, Medline and CINAHL databases. Additional references were identified from this literature. Sentinel articles and books were manually searched to identify key concepts. Search words used were nurse, nursing, image and self‐image. The findings were examined using the framework of Strasen's self‐image model.

Findings. Public image appears to be intimately intertwined with nurse image. This creates the boundaries that confine and construct the image of nursing. As a profession, nurses do not have a very positive self‐image nor do they think highly of themselves.

Conclusion. Individually, each nurse has the power to shape the image of nursing. However, nurses must also work together to change the systems that perpetuate negative stereotypes of nurses’ image.
Which factors are associated with a successful outcome in a weight management programme for obese children?
Authors: Sabin Matthew A. , Ford Anna , Hunt Linda , Jamal Riyaz , Crowne Elizabeth C. , Shield Julian P. H.
Published: May 2007

Aims and objective  To identify factors important in determining whether an obese child achieves significant reductions in Body Mass Index Standard Deviation Score (BMI SDS) within a UK, hospital‐based paediatric obesity service aimed at lifestyle modification.

Design  Observational Study.

Subjects  137 obese children (63 boys) who have attended our childhood obesity service within the last three and a half years at The Royal Hospital for Children, Bristol, UK.

Measurements  BMI SDS with a target reduction of – 0.5 or greater.

Results  70% of children achieved reductions in BMI SDS with 18% achieving the target reduction. In those attending the clinic for a year or more the levels improved to 83% and 28% respectively. Age was found to be the most important predictor with younger children achieving larger reductions in BMI SDS. More boys than girls were likely to achieve target reductions in BMI SDS and those without a parental history of obesity were more likely to achieve greater reductions in BMI SDS. Socio‐economic status did not appear to impact upon the child’s level of success.

Conclusions  In families of obese children, motivated to seek help by attending a hospital‐based weight control clinic, improvements in BMI are possible by a simple approach of education and continued support. Improvement is greatest in younger children with maximal benefit being seen in boys without a parental history of obesity. We believe this emphasizes the importance of identifying significant obesity in primary school aged children, who seem most likely to benefit from simple lifestyle modification, while many older children may require additional intervention programmes to improve BMI.
Bridging the gap between clinical practice and diagnostic clinical epidemiology: pilot experiences with a didactic model based on a logarithmic scale
Authors: Van den Ende Jef , Bisoffi Zeno , Van Puymbroek Hugo , Van der Stuyft Patrick , Van Gompel Alfons , Derese Anselm , Lynen Lutgarde , Moreira Juan , Janssen Paul Adriaan Jan
Published: May 2007

Rationale  From general practitioners to academic staff, clinicians continue to have difficulties in applying clinical epidemiology in their everyday work. They do not fully understand the logical rules behind the numbers and they do not recognize these rules in their work. We present a new model where the pre‐test and the post‐test probabilities are converted to log10 of odds, and the likelihood ratio (LR) to its own log10.

Methods  Following Bayes’ theorem, adding the log10LR to the log10 pre‐test odds gives the log10 post‐test odds, which can easily be represented on a logarithmic scale. In addition, by rounding the log10LR to half the unit, we create classes of discriminative power of tests, close to intuitive estimation. This model generates also a user‐friendly diagram, adding considerably to the understanding of Bayes’ theorem. We evaluated the effect of the rounding, the current use of the classical model and the acceptability of the new model.

Results  Rounding 10 disease characteristics to half the unit gives an absolute error of less than half a unit. After six explanations of Bayes’ theorem, only 6/16 medical students were capable of answering simple questions about predictive value. When asked about weight of disease characteristics, no one of the 50 clinicians mentioned sensitivity, specificity, predictive value or LR. With the new model, more than 80% of trainees found medical decision making easier to understand and recognized the theory in their practice.

Conclusions  We conclude that our model of diagnostic clinical epidemiology offers a logical environment for an easy and rapid assessment of the evolution of disease probability with consecutive tests, providing a scientific format for ‘qualitative’ clinical estimations.
Safety and efficacy of an induction dose of pegylated interferon alpha‐2a on early hepatitis C virus kinetics in HIV/HCV co‐infected patients: the CORAL‐1 multicentre pilot study
Authors: Tural C. , Solà R. , Rubio R. , Santín M. , Planas R. , Quereda C. , Berenguer J. , Montes‐Ramírez M. , Clotet B. ,   and the CORAL‐1 study group
Published: May 2007

summary.  To evaluate the safety and efficacy of an induction dose of pegylated interferon alpha 2a (IFN‐α2a) on the 12‐week hepatitis C virus (HCV) kinetics in human immunodeficiency virus (HIV) patients co‐infected with HCV. One hundred sixteen HIV/HCV co‐infected patients from nine hospitals in Spain were randomized to receive 270 μg/week of pegylated IFN‐α2a for 4 weeks followed by 180 μg/week for 8 weeks or 180 μg/week for 12 weeks. Ribavirin was given at a daily dose of 1000 or 1200 mg. The main outcome measure was the percentage of patients achieving an HCV‐RNA below 50 IU/mL or a decrease of 2 or more log10 at week 12 (early virologic response, EVR). HCV‐RNA was measured at baseline, weekly, for the first 4 weeks and monthly thereafter. We observed no difference in the percentage of patients achieving an EVR between arms (on‐treatment, 74% in both arms; intention‐to‐treat, 70% in the induction arm and 67% in the control arm), nor were there differences in the percentage achieving an undetectable HCV qualitative polymerase chain reaction at any time points or in the decrease in HCV‐RNA from baseline. No differences were found between arms in the percentage of dropouts (8% in the whole study population). Our study failed to find a benefit of an induction dose of 270 μg/week of pegylated IFN‐α2a for 4 weeks on the EVR in co‐infected patients who are treatment naive. Despite the lack of benefit with this regimen, induction therapy with this schedule was safe and well tolerated in co‐infected patients.
Spontaneous deletions and reciprocal translocations in Saccharomyces cerevisiae: influence of ploidy
Authors: Tourrette Yves , Schacherer Joseph , Fritsch Emilie , Potier Serge , Souciet Jean‐Luc , De Montigny Jacky
Published: May 2007

Studying spontaneous chromosomal rearrangements throws light on the rules underlying the genome reshaping events occurring in eukaryotic cells, which are part of the evolutionary process. In Saccharomyces cerevisiae, translocation and deletion processes have been frequently described in haploids, but little is known so far about these processes at the diploid level. Here we investigated the nature and the frequency of the chromosomal rearrangements occurring at this ploidy level. Using a positive selection screen based on a particular mutated allele of the URA2 gene, spontaneous diploid revertants were selected and analysed. Surprisingly, the diploid state was found to be correlated with a decrease in chromosome rearrangement frequency, along with an increase in the complexity of the rearrangements occurring in the target gene. The presence of short DNA tandem repeat sequences seems to be a key requirement for deletion and reciprocal translocation processes to occur in diploids. After discussing the differences between the haploid and diploid levels, some mechanisms possibly involved in chromosome shortening and arm exchange are suggested.
Antirepression as a second mechanism of transcriptional activation by a minor groove binding protein
Authors: Smits Wiep Klaas , Hoa Tran Thu , Hamoen Leendert W. , Kuipers Oscar P. , Dubnau David
Published: May 2007

Competence for genetic transformation in the bacterium Bacillus subtilis is a bistable differentiation process governed by the minor groove DNA binding protein ComK. No detectable comK transcription occurs in the absence of an intact comK gene, indicating that ComK has auto‐activating properties. ComK auto‐stimulation, which is dependent on ComK binding to the comK promoter, is a critical step in competence development, ensuring quick and high‐level expression of the late‐competence genes. Auto‐stimulation is also essential for the bistable expression pattern of competence. Here, we demonstrate that ComK acts as an activator at its own promoter by antagonizing the action of two repressors, Rok and CodY. Importantly, antirepression occurs without preventing binding of the repressing proteins, suggesting that ComK and the repressors might bind at distinct surfaces of the DNA helix. DegU, a DNA binding protein known to increase the affinity of ComK for its own promoter, potentiates the antirepression activity of ComK. We postulate that antirepression is primarily achieved through modulation of DNA topology. Although to our knowledge ComK is the only DNA binding protein shown to act in this novel fashion, other minor groove binding proteins may act similarly.
Differences intrans‐stimulated chloroquine efflux kinetics are linked to PfCRT inPlasmodium falciparum
Authors: Sanchez Cecilia P. , Rohrbach Petra , McLean Jeremy E. , Fidock David A. , Stein Wilfred D. , Lanzer Michael
Published: May 2007

The mechanism underpinning chloroquine drug resistance in the human malarial parasitePlasmodium falciparumhas remained controversial. Currently discussed models include a carrier or a channel for chloroquine, the former actively expelling the drug, the latter facilitating its passive diffusion, out of the parasite's food vacuole, where chloroquine accumulates and inhibits haem detoxification. Here we have challenged both models using an establishedtrans‐stimulation efflux protocol. While carriers may demonstratetrans‐stimulation, channels do not. Our data reveal that extracellular chloroquine stimulates chloroquine efflux in the presence and absence of metabolic energy in both chloroquine‐sensitive and ‐resistant parasites, resulting in a hyperbolic increase in the apparent initial efflux rates as the concentration of external chloroquine increases. In the absence of metabolic energy, the apparent initial efflux rates were comparable in both parasites. Significant differences were only observed in the presence of metabolic energy, where consistently higher apparent initial efflux rates were found in chloroquine‐resistant parasites. Astrans‐stimulation is characteristic of a carrier, and not a channel, we interpret our data in favour of a carrier for chloroquine being present in both chloroquine‐sensitive and ‐resistant parasites, however, with different transport modalities.
Identification and biochemical characterization of a novel carotenoid oxygenase: elucidation of the cleavage step in the Fusarium carotenoid pathway
Authors: Prado‐Cabrero Alfonso , Estrada Alejandro F. , Al‐Babili Salim , Avalos Javier
Published: May 2007

The synthesis of the acidic apo‐carotenoid neurosporaxanthin by the fungus Fusarium fujikuroi depends on four enzyme activities: phytoene synthase and carotene cyclase, encoded by the bifunctional gene carRA, a carotene desaturase, encoded by carB, and a postulated cleaving enzyme converting torulene (C40) into neurosporaxanthin (C35). Based on sequence homology to carotenoid oxygenases, we identified the novel fungal enzyme CarT. Sequencing of the carT allele in a torulene‐accumulating mutant of F. fujikuroi revealed a mutation affecting a highly conserved amino acid, and introduction of a heterologous carT gene in this mutant restored the ability to produce neurosporaxanthin, pointing to CarT as the enzyme responsible for torulene cleavage. Expression of carT in lycopene‐accumulating E. coli cells resulted in the formation of minor amounts of apo‐carotenoids, but no enzymatic activity was observed in β‐carotene‐accumulating cells, indicating a preference for acyclic or monocyclic carotenes. The purified CarT enzyme efficiently cleaved torulene in vitro to produce β‐apo‐4′‐carotenal, the aldehyde corresponding to the acidic neurosporaxanthin, and was also active on other monocyclic synthetic substrates. In agreement with its role in carotenoid biosynthesis, the carT transcript levels are induced by light and upregulated in carotenoid‐overproducing mutants, as already found for other car genes.