bluuebunny/crossref_metadata_2025_split huggingface dataset:
Should the use of modified Jackson Rees T‐piece breathing system be abandoned in preschool children?
Authors: UNGERN‐STERNBERG BRITTA S. VON , SAUDAN SONJA , REGLI ADRIAN , SCHAUB EMMANUEL , ERB THOMAS O. , HABRE WALID ,   ON BEHALF OF THE SWISS PEDIATRIC RESPIRATORY RESEARCH GROUP
Published: May 2007

SummaryBackground:  The Jackson Rees breathing system is commonly used for bag and mask ventilation in preschool children, although the lack of a pressure release valve can increase the risk of gastric insufflation. Therefore, we investigated the impact of bag and mask ventilation with a Jackson Rees system on functional residual capacity (FRC) and ventilation homogeneity and evaluated the effect of the level of training of the anesthesiologist in charge.Methods:  Functional residual capacity and ventilation homogeneity were measured in 74 children (1–6 years) undergoing general surgery and the level of training of the anesthesiologist was recorded. FRC was measured (i) after intubation and (ii) after gastric emptying. Sixty‐four children were ventilated using a Jackson Rees system, whereas 10 children were ventilated using a circle system to compare these two breathing systems in the second phase of the protocol.Results:  Functional residual capacity and ventilation homogeneity increased in all patients following gastric emptying with the highest improvement (25%) being observed when nurse students were in charge of the ventilation with the Jackson Rees system. The lowest changes in FRC and ventilation homogeneity were observed when pediatric consultants were in charge, whereas ventilation by the pediatric nurse anesthetists led to significant gastric gas insufflation. However, the circle system was associated with significantly less gastric insufflation than the Jackson Rees system.Conclusions:  The efficacy of bag and mask ventilation was highly dependent on the training of the anesthesiologist with consultants demonstrating significantly better skills than any of the other groups. As the circle system is associated with a much steeper learning curve than the Jackson Rees system, its use in daily routine practice may prevent ventilatory impairment induced by gastric insufflation.
Paediatric propofol pharmacokinetics: a multicentre study
Authors: Rigby‐Jones AE , Priston MJ , Wolf AR , Sneyd JR 
Published: May 2007

Introduction:  Schuttler and Imhsens propofol pharmacokinetic (PK) model (1) based on pooled adult and paediatric data lacked information for the smallest patients. We conducted a pooled population analysis of available neonatal and paediatric propofol PK data. The variable clinical circumstances of the individual studies allowed us to explore health status as a PK model covariate.Methods:  We combined raw propofol blood/plasma concentration vs time data, dosing information and demographic data from eight paediatric studies conducted by six research groups, with our data (2,3). The pooled data set comprised 197 individuals (2315 observations), aged 0.02–12.25 years (2.75–60.5 kg, median 15 kg). In this preliminary population PK analysis using NONMEM, the basic model structure was established before all model parameters were allometrically scaled to body weight. The influence of health status on paediatric propofol PK was explored.Results:  In this 3‐compartment preliminary model, postcardiac surgery patients have significantly reduced metabolic clearance rates (31–45% less when compared with healthy children or noncardiac PICU patients). The volume of the deep peripheral compartment in critically ill and postcardiac surgery children is 319% and 205% larger, respectively, than in healthy children, see Table 1.

PK values for a child weighing 15 kg

Parameter
Typical Value
95% Confidence Interval

CL (l·min‐1)

Healthy
0.614
0.563–0.665

PICU
0.767
0.628–0.906

PICU cardiac
0.421
0.366–0.476

Q2 (l·min‐1)
0.839
0.703–0.975

Q3 (l·min‐1)
0.252
0.221–0.283

V1 (l)
7.76
6.33–9.19

V2 (l)
14.4
12.8–16.0

V3 (l)

Healthy
83.9
61.4–106

PICU
268
183–353

PICU cardiac
172
117–227
A synthesis of experimental work on parasite local adaptation
Authors: Greischar Megan A. , Koskella Britt 
Published: May 2007

AbstractThe study of parasite local adaptation, whereby parasites perform better on sympatric hosts than on allopatric hosts and/or better on their own host population than do other parasites, is of great importance to both basic and applied biology. Theoretical examination of host–parasite coevolution predicts that parasite migration rate, generation time and virulence all contribute to the pattern of parasite local adaptation, such that parasites with greater dispersal ability, more frequent reproduction and/or high virulence ought to exhibit increased infectivity on local hosts. Here, we present a meta‐analysis of experimental work from 57 host–parasite systems across 54 local adaptation studies to directly test theoretical predictions concerning the effect of each attribute on parasite adaptation. As expected, we find that studies of parasites with higher migration rates than their hosts report local adaptation, as measured by infection success, significantly more often than studies of parasites with relatively low migration rates. Furthermore, this synthesis serves to identify biases in the current body of work and highlight areas with the greatest need for further study. We emphasize the importance of unifying the field with regard to experimental methods, local adaptation definitions and reported statistics for cross‐infection studies.
Stress and domestication traits increase the relative fitness of crop–wild hybrids in sunflower
Authors: Mercer Kristin L. , Andow David A. , Wyse Donald L. , Shaw Ruth G. 
Published: May 2007

AbstractAfter a decade of transgenic crop production, the dynamics of gene introgression into wild relatives remain unclear. Taking an ecological genetics approach to investigating fitness in crop–wild hybrid zones, we uncovered both conditions and characteristics that may promote introgression. We compared diverse crop–wild hybrid genotypes relative to wildHelianthus annuusunder one benign and three stressful agricultural environments. Whereas relative fitness of crop–wild hybrids averaged 0.25 under benign conditions, with herbicide application or competition it reached 0.45 and was more variable. In some instances, hybrid fitness matched wild fitness (≈ 1). Thus, wild populations under agronomic stress may be more susceptible to introgression. Although ‘domestication’ traits are typically considered unlikely to persist in wild populations, we found some (e.g. rapid growth and early flowering) that may enhance hybrid fitness, especially in stressful environments. Rigorous assessment of how particular genotypes, phenotypes, and environments affect introgression will improve risk assessment for transgenic crops.
Scales of association: hierarchical linear models and the measurement of ecological systems
Authors: McMahon Sean M. , Diez Jeffrey M. 
Published: May 2007

AbstractA fundamental challenge to understanding patterns in ecological systems lies in employing methods that can analyse, test and draw inference from measured associations between variables across scales. Hierarchical linear models (HLM) use advanced estimation algorithms to measure regression relationships and variance–covariance parameters in hierarchically structured data. Although hierarchical models have occasionally been used in the analysis of ecological data, their full potential to describe scales of association, diagnose variance explained, and to partition uncertainty has not been employed. In this paper we argue that the use of the HLM framework can enable significantly improved inference about ecological processes across levels of organization. After briefly describing the principals behind HLM, we give two examples that demonstrate a protocol for building hierarchical models and answering questions about the relationships between variables at multiple scales. The first example employs maximum likelihood methods to construct a two‐level linear model predicting herbivore damage to a perennial plant at the individual‐ and patch‐scale; the second example uses Bayesian estimation techniques to develop a three‐level logistic model of plant flowering probability across individual plants, microsites and populations. HLM model development and diagnostics illustrate the importance of incorporating scale when modelling associations in ecological systems and offer a sophisticated yet accessible method for studies of populations, communities and ecosystems. We suggest that a greater coupling of hierarchical study designs and hierarchical analysis will yield significant insights on how ecological processes operate across scales.
Synchrony's double edge: transient dynamics and the Allee effect in stage structured populations
Authors: Friedenberg Nicholas A. , Powell James A. , Ayres Matthew P. 
Published: May 2007

AbstractIn populations subject to positive density dependence, individuals can increase their fitness by synchronizing the timing of key life history events. However, phenological synchrony represents a perturbation from a population's stable stage structure and the ensuing transient dynamics create troughs of low abundance that can promote extinction. Using an ecophysiological model of a mass‐attacking pest insect, we show that the effect of synchrony on local population persistence depends on population size and adult lifespan. Results are consistent with a strong empirical pattern of increased extinction risk with decreasing initial population size. Mortality factors such as predation on adults can also affect transient dynamics. Throughout the species range, the seasonal niche for persistence increases with the asynchrony of oviposition. Exposure to the Allee effect after establishment may be most likely at northern range limits, where cold winters tend to synchronize spring colonization, suggesting a role for transient dynamics in the determination of species distributions.
Effects of anaesthesia on the nitrergic pathway during the micturition reflex in rats
Authors: Masuda Hitoshi , Ogawa Teruyuki , Kihara Kazunori , Chancellor Michael B. , De Groat William C. , Yoshimura Naoki 
Published: May 2007

OBJECTIVETo investigate the effects of anaesthesia on the nitrergic pathway during the micturition reflex in rats.MATERIALS AND METHODSThe effects of NG‐nitro‐l‐arginine methyl ester (L‐NAME), an inhibitor of nitric oxide (NO) synthase, on bladder and urethral activities were evaluated by infusion cystometrography (CMG) and urethral perfusion pressure under isovolumetric conditions in awake or urethane‐anaesthetized rats. L‐NAME was administered intravenously (i.v.), intrathecally (i.t.), intracerebroventriculary (i.c.v.) or intravesically in normal rats or rats pre‐treated with resiniferatoxin, a potent C‐fibre afferent neurotoxin.RESULTSL‐NAME injected i.v. decreased the intercontraction interval (ICI) in the awake but increased it in the anaesthetized rats. L‐NAME injected i.t. increased the ICI in both states and these effects were not apparent after pre‐treatment with resiniferatoxin. L‐NAME injected i.c.v. decreased the ICI in the awake but increased i.t. in the anaesthetized rats. Intravesical L‐NAME decreased the ICI in the awake but not in the anaesthetized rats. L‐NAME administered i.v., but not i.t. or i.c.v., increased bladder contraction during CMG. Under isovolumetric conditions, L‐NAME administered i.v., but not i.t. or i.c.v., reduced the urethral relaxation without changing bladder contraction.CONCLUSIONSThese results indicate that spinal NO release facilitates the mechanoceptive C‐fibres, and this facilitatory effect is masked by supraspinal (possibly forebrain) and local inhibitory effects of NO during the micturition reflex in awake rats. Urethane seems to inhibit the supraspinal and local inhibitory effects of NO, resulting in unmasking the facilitatory effect of NO in the spinal cord and brain stem. During the voiding phase, urethral relaxation depends on the peripheral but not the central NO system.
Reconsidering the use of the International Index of Erectile Function questionnaire in evaluating the preoperative erectile function status of patients undergoing radical prostatectomy
Authors: Papadoukakis Stefanos , Kusche Dirk , Stolzenburg Jens Uwe , Truss Michael C. 
Published: May 2007

OBJECTIVETo assess the use of the International Index of Erectile Function (IIEF), routinely used in patients being treated for localized prostate cancer, including potency‐preserving, nerve‐sparing radical prostatectomy (RP), as many patients complain that the results of the IIEF over 4 weeks before RP are not representative.PATIENTS AND METHODSThe study included 123 consecutive patients (mean age 64.6 years, range 52–78) who had endoscopic‐extraperitoneal RP and who completed the IIEF. The interval between the diagnosis of the disease and surgery was >4 weeks in all. The patients completed the same questionnaire referring to the last 4 weeks before their prostate biopsy, as a modified index of their sexual status (IIEFm and EFm).RESULTSThe clinical stage of disease was cT1c (34.9%), cT2a (49.5%), cT2b (5.7%) and cT2c (9.9%) before RP. The mean IIEF score was 42.8 and the mean EF domain score was 16.9; the mean IIEFm was 54.9 and the EFm domain score was 23.7. All the differences were statistically significant (P < 0.001).CONCLUSIONThe IIEF questionnaire scores are influenced by many factors. Depression after a diagnosis of cancer, and the prostate biopsy‐related symptoms, e.g. prostatitis, perineal pain and haemospermia, might compromise the patients’ well‐being and libido, and thus affect the IIEF scores before RP. We therefore suggest using the IIEFm and EFm scores before prostate biopsy to assess the patients’ sexual status before any treatment for localized prostate cancer.
Analysis of the efficacy and safety of sildenafil citrate in the geriatric population
Authors: Müller Alexander , Smith Lizette , Parker Marilyn , Mulhall John P. 
Published: May 2007

Associate EditorMichael G. WyllieEditorial BoardIan Eardley, UKJean Fourcroy, USASidney Glina, BrazilJulia Heiman, USAChris McMahon, AustraliaBob Millar, UKAlvaro Morales, CanadaMichael Perelman, USAMarcel Waldinger, NetherlandsOBJECTIVETo define the efficacy and tolerability of sildenafil in elderly men, as epidemiological data show an increasing life‐expectancy of the population, and age is not only correlated with increasing morbidity but also an increase in the prevalence of erectile dysfunction (ED), for which sildenafil, available for >8 years, is effective and safe across a wide variety of medical comorbidities, severity and causes of ED.PATIENTS AND METHODSA database was generated from all sildenafil users in one sexual medicine practice, and data were extracted for men aged >60 years. The database included data on patient demographics, comorbidities, International Index of Erectile Function (IIEF) scores and adverse events (AEs). The patients were subdivided into those aged 60–69 (group 1), 70–79 (group 2), and ≥ 80 years (group 3). Analysis of variance was used to assess differences among the three groups for several variables of demographics and erectile response.RESULTSIn all, 167 patients were analysed; there were no significant differences in the duration of ED (5 ± 3 years) or presence of comorbidities among the three groups. With a mean of two risk factors, the overall incidence of comorbidities was hypertension in 37%, dyslipidaemia in 28%, diabetes in 26%, coronary artery disease in 18% and lower urinary tract symptoms in 46%. The efficacy data showed that overall, 54% of men responded to sildenafil, with a mean increase in IIEF EF domain score of 5.7. Within the three groups there was a significant age‐related decrease in response rate and IIEF EF domain score with age. However, there was no difference in AE incidence among the three groups, with an overall profile of 18% headache, 8% flushing, 8% dyspepsia, 5% nasal congestion and 2% visual changes. No overt cardiovascular events were reported.CONCLUSIONSFrom these data, sildenafil is an effective agent in elderly men, but had a lower efficacy rate with increasing age, especially in men aged >80 years. The incidence of side‐effects was similar to that in the general population taking sildenafil, with no difference in AEs among the different age groups
Distribution of prostate specific antigen (PSA) and percentage free PSA in a contemporary screening cohort with no evidence of prostate cancer
Authors: Chun Felix K.‐H. , Hutterer Georg C. , Perrotte Paul , Gallina Andrea , Valiquette Luc , Benard Francois , McCormack Michael , Briganti Alberto , Ionescu Constantin , Jeldres Claudio , Guay Jean‐Pierre , Saad Fred , Karakiewicz Pierre I. 
Published: May 2007

OBJECTIVETo explore the distribution of total prostate specific antigen (PSA) and percentage free/total PSA (%f/tPSA) in healthy volunteers with no clinical evidence of prostate cancer, who participated in prostate cancer screening.SUBJECTS AND METHODSPSA and %f/tPSA values from 2323 men, who participated in one of three annual prostate cancer screening events between 2004 and 2006, were tabulated according to age strata of 40–49, 50–59, 60–69 and 70–79 years. Local regression smoothing plots provided a graphical display of the relation between age and PSA or %f/tPSA, respectively. All PSA and %f/tPSA analyses were repeated for each age category after excluding, respectively, the top and the bottom 10% of PSA and %f/tPSA values.RESULTSWithin the entire cohort, the median PSA level was 1.0 ng/mL and the median %f/tPSA was 25%. According to the age categories the PSA level and %f/tPSA medians within the entire cohort were, respectively, 0.7, 0.9, 1.3, 1.8 ng/mL and 28.0, 26.0, 24.0 and 25.0%. Of the 2323 men, 438 (18.9%) had a PSA level of >2.5 ng/mL and 1172 (50.5%) had a %f/tPSA of ≤ 25%. When either a PSA level of >2.5 ng/mL or a %f/tPSA of ≤ 25% were considered, 1235 (53.2%) had one or two abnormal values. Finally, if either a PSA level of >2.5 ng/mL or %f/tPSA of ≤ 15% was used, 617 (26.6%) were considered abnormal.CONCLUSIONHalf of men with no clinical evidence of prostate cancer should have PSA levels of <1.0 ng/mL and a %f/tPSA of >25%. A PSA level threshold of 2.5 ng/mL would require a biopsy in 20% of men and a %f/tPSA threshold of ≤ 25% in half of the men. Alternatively, a %f/tPSA threshold of ≤ 15% would decrease the probability to 15%.
Phytoestrogens from Belamcanda chinensis regulate the expression of steroid receptors and related cofactors in LNCaP prostate cancer cells
Authors: Thelen Paul , Peter Thomas , Hünermund Anika , Kaulfuß Silke , Seidlová‐Wuttke Dana , Wuttke Wolfgang , Ringert Rolf‐Hermann , Seseke Florian 
Published: May 2007

OBJECTIVETo investigate the changes in expression underlying the marked reduction of tumour growth in vivo, by analysing the effect of Belamcanda chinensis extract (BCE) on LNCaP cells in vitro, as phytoestrogens are chemopreventive in prostate cancer, and in previous studies we examined the effects of the isoflavone tectorigenin isolated from B. chinensis on LNCaP prostate cancer cells, and a BCE consisting of 13 phytoestrogenic compounds on tumour‐bearing nude mice.MATERIALS AND METHODSLNCaP cells were treated with 100, 400 or 1400 µg/mL BCE; proliferation was assessed with an Alamar Blue assay. We used real‐time reverse transcription‐polymerase chain reaction to quantify mRNA expression of the androgen receptor (AR), the AR coactivator prostate derived Ets transcription factor (PDEF), NKX3.1, prostate specific antigen (PSA) and oestrogen receptor‐β (ER‐β) compared with the expression of the housekeeping gene porphobilinogen deaminase (PBGD). PSA secretion from LNCaP cells was measured and protein expression of the AR investigated by Western blot analysis.RESULTSConcomitant with a marked decrease of tumour cell proliferation BCE down‐regulated the expression of the AR, PDEF, NKX3.1 and PSA. In the same experiments, the expression of PBGD was unaltered, whereas ER‐β expression increased. Furthermore, AR protein and PSA secretion were markedly diminished after treatments with the BCE.CONCLUSIONBCE, comprising 13 different phytoestrogens, decreases the expression of the AR and its co‐activator PDEF concomitant with diminished cell proliferation and PSA secretion. NKX3.1 expression was also reduced by BCE. We hypothesise that the positive effects of BCE are initiated by up‐regulation of the ER‐β, a putative tumour‐suppressor gene.
Empowerment among Latina nurses in Mexico, New York and Indiana
Authors: Baker C. M. , McDaniel A. M. , Fredrickson K. C. , Gallegos E. C. 
Published: May 2007

Background:  Increasing empowerment among nurses may help retain nurses and increase the international workforce. There are very few cross‐national studies of nurse empowerment reported in the professional literature.Aim:  To conduct a cross‐national exploratory study testing a theoretical model of nurse empowerment.Design:  Descriptive survey of three convenience samples of graduate Latina nurses in Monterrey, Mexico, New York City and Indiana.Methods:  Data were collected using self‐administered questionnaires. The Klakovich Reciprocal Empowerment Scale (RES) was translated into Mexican‐Spanish using a translation back‐translation technique. Variables for the study included empowerment, years of experience, job satisfaction and intent to stay. Frequency distributions and descriptive statistics were used to analyse the data.Findings:  Empowerment involves reciprocity between the leader and follower, a common vision and synergy about the work, and a sense of ownership in the work site. Mexican nurses scored significantly higher on synergy than Latina nurses in New York and Indiana. Empowerment is related to job satisfaction, age and years of employment.Conclusions:  Results indicate the usefulness of the RES instrument for Latina nurses and the need for further research with larger samples. Cross‐national research provides culturally sensitive information. Such research partnerships facilitate modelling the importance of nursing research to graduate nurses and students.
Community mental health care in Botswana: approaches and opportunities
Authors: Seloilwe E. S. , Thupayagale‐Tshweneagae G. 
Published: May 2007

Aim:  The purpose of this article is to provide an insight into the developmental trends in community mental health care in Botswana. Different approaches are discussed and the opportunities that have emanated from them.Background:  Care of the mentally ill in Botswana is provided at different levels of coverage and sophistication. There is a single mental hospital in the country. Attached to the district hospitals are psychiatric outpatient clinics run by psychiatric nurses and a psychiatrist who visits them on monthly basis. Mental health care in Botswana has gone through a paradigm shift, from the prepenal years, penal years and institutional to community based care, which reflects a philosophy of citizen involvement and collaboration.Conclusion:  Several approaches have been utilized in the development of community mental health care. However, difficulties and challenges still exist in the provision of community mental health care.