Hydrodynamics of the renal pelvis

Considerable differences exist in the findings of workers who have studied the hydrodynamics of the renal pelvis. By some woodside 1944 the pelvis is regarded as pump, whilst others tiil 1957 have suggested that it functions as a relatively inert reservoir. There is, therefore, no agreement about the part played by the renal pelvis in the transport of urine. In strict anatomical terms the renal pelvic of the clinician, is described as the "pelvis of the ureter" (Cunningham 1943, Cray 1962), as morphological and histological evidence indicate that the pelvis is a part of the ureter. Urological usage, however, has not followed this precept and as this term, "renal pelvis" has gained general acceptance, it has been used throughout the text. There has been a paucity of studies on the hydrodynamics of the renal pelvis, possibly because the pelvis is not easily accessible for studies of function, and because, until the 1950's only water manometers were available for measuring intrapelvic pressures. Water manometers record fluid displacent of relatively large volume and so cannot aceurately measure the pressure changes associated with the transport of small volume of urine in the upper urinary tract. The mere refined manometers. Developed for cardiovascular research, were first used to measure pressures in the renal pelvis in man by kill 1953. As pressures were measured through small ureteric catheters connected to stathan physiological pressure transducers the problems of fluid displacement were overcome, but the question of whether the indwelling ureteric catheter seriously distorted ureteric dynamics has not been satisfactorily answered. Kiil believed that, provided the ureteric catheters were small, there was no significant obstruction to urine flow, as he had found that pressures in the renal pelvis were low and did not increase with prolonged periods of recording. However, other workers (rattner, fink and murphy 1957) using similar methods have recorded very much higher pressures in the renal pelvis. It is important that accurate pressures are obtained from the renal pelvis as these will provide information about the emptying mechanism of the renal pelvis and possibly contribute to an understanding of the aetiology of some types of hydronephrosis. It therefore seemed desirable that an attempt should be made to measure interapelvic pressures by a method which could not interfere with ureteric dynamics. An examination of the anatomy of the pelvis suggested that this difficulty could be overcome by inserting a manometric tube through the renal parenchyma into the pelvis. This method would not, of course be suitable for measuring pelvic pressures in man, but could be used in the dog. In this thesis, studies are describe on pelvic pressures recorded through "permanent" manometric nephrostomy tubes in the dog. To obtain the fullest possible knowledge, pelvic pressures were measured systematically throught a range of urine flow rates up to maximum diuresis, and other possible factors affecting pelvic pressures were also examined. In this way, it seemed possible that more information would be gained about the pressures in the renal pelvis and hence about its orle in the transport of urine

The inter-item standard deviation (ISD): An index that discriminates between conscientious and random responders

Although random responding is prevalent and increases Type II errors, most psychologists avoid trying to identify it because the means to do so are extremely limited. We propose the inter-item standard deviation (ISD), a statistical index of response variance, is suited for this task. We hypothesized that random responders produce large ISDs because they respond to items all over a measure’s response range, whereas conscientious responders produce small ISDs because they respond to items more consistently. We administered a questionnaire containing the NEO-FFI-3 and an embedded validity scale to 134 university students. Another 134 responders were created using a random number generator. For all 268 responders, the ISD was calculated for each of the NEO-FFI-30 s five subscales and an aggregated ISD was calculated by averaging the five ISD indexes. Results showed that (1) random responders produce significantly larger ISDs than conscientious responders, (2) the ISDs were strongly correlated with the embedded validity scale and with one another, and (3) the ISDs correctly identified responders with greater than 80% classification accuracy. The mean ISD yielded greater than 95% classification accuracy. This study shows that responders can be identified by quantifying inter-item response variance.Social Sciences and Humanities Research Council (SSHRC

QT peak prolongation predicts cardiac death following stroke

Cardiac death has been linked in many populations to prolongation of the QT interval (QTe). However, basic science research suggested that the best estimate of the time point when repolarisation begins is near the T-wave peak. We found QT peak (QTp) was longer in hypertensive subjects with LVH. A prolonged “depolarisation” phase, rather than “repolarisation” (T peak to T end) might therefore account for the higher incidence of cardiac death linked to long QT. Hypothesis: We have tested the hypothesis that QT peak (QTp) prolongation predicts cardiac death in stroke survivors. Methods and Results: ECGs were recorded from 296 stroke survivors (152 male), mean age 67.2 (SD 11.6) approximately 1 year after the event. Their mean blood pressure was 152/88 mmHg (SD 29/15mmHg). These ECGs were digitised by one observer who was blinded to patient outcome. The patients were followed up for a median of 3.3 years. The primary endpoint was cardiac death. A prolonged heart rate corrected QT peak (QTpc) of lead I carried the highest relative risk of death from all cause as well as cardiac death, when compared with the other more conventional QT indices. In multivariate analyses, when adjusted for conventional risk factors of atherosclerosis, a prolonged QTpc of lead I was still associated with a 3-fold increased risk of cardiac death. (adjusted relative risk 3.0 [95% CI 1.1 - 8.5], p=0.037). Conclusion: QT peak prolongation in lead I predicts cardiac death after strok

The Conscientious Responders Scale: A new tool for discriminating between conscientious and random responders

This investigation introduces a novel tool for identifying conscientious responders (CRs) and random responders (RRs) in psychological inventory data. The Conscientious Responders Scale (CRS) is a five-item validity measure that uses instructional items to identify responders. Because each item instructs responders exactly how to answer that particular item, each response can be scored as either correct or incorrect. Given the long odds of answering a CRS item correctly by chance alone on a 7-point scale (14.29%), we reasoned that RRs would answer most items incorrectly, whereas CRs would answer them correctly. This rationale was evaluated in two experiments in which CRs’ CRS scores were compared against RRs’ scores. As predicted, results showed large differences in CRS scores across responder groups. Moreover, the CRS correctly classified responders as either conscientious or random with greater than 93% accuracy. Implications for the reliability and effectiveness of the CRS are discussed.Social Sciences and Humanities Research Council (SSHRC

High seroprevalence of human herpesviruses in HIV-infected individuals attending primary healthcare facilities in rural South Africa

Seroprevalence data of human herpesviruses (HHVs) are limited for sub-Saharan Africa. These are important to provide an indication of potential burden of HHV-related disease, in particular in human immunodeficiency virus (HIV)-infected individuals who are known to be at increased risk of these conditions in the Western world. In this cross-sectional study among 405 HIV-infected and antiretroviral therapy naïve individuals in rural South Africa the seroprevalence of HHVs was: herpes simplex virus type 1 (HSV-1) (98%), herpes simplex virus type 2 (HSV-2) (87%), varicella zoster virus (VZV) (89%), and 100% for both Epstein-Barr virus (EBV) and cytomegalovirus (CMV). Independent factors associated with VZV seropositivity were low educational status and having children. Lack of in-house access to drinking water was independently associated with positive HSV-1 serostatus, whereas Shangaan ethnicity was associated with HSV-2 seropositivity. Increasing age was associated with higher IgG titres to both EBV and CMV, whereas CD4 cell count was negatively associated with EBV and CMV IgG titres. Moreover, IgG titres of HSV-1 and 2, VZV and CMV, and CMV and EBV were positively correlated. The high HHV seroprevalence emphasises the importance of awareness of these viral infections in HIV-infected individuals in South Africa

Dehydroalanine and Lysinoalanine in Thermolyzed Casein do not Promote Colon Cancer in the Rat

Thermolysis of proteins produces xenobiotic amino-acids such as the potentially toxic lysinoalanine, and the alkylating agent, dehydro¬alanine, which have been considered possible health hazards. We observed that thermolysed casein promoted aberrant crypt foci (ACF) and colon cancer growth in rats initiated with azoxymethane and speculated that promotion might be due to the formation of these compounds. To test this notion we first measured the concentration of the modified amino acids as a function of thermolysis time. The concentration of dehydroalanine in the casein paralleled the degree of promotion, that of lysinoalanine did not. We then tested diets containing foods with high levels of dehydroalanine (thermolysed sodium-caseinate, cooked Swiss cheese) for their effect on ACF promotion. They decreased the number and/or size of ACF significantly, indicating that dehydroalanine did not promote, but protected rats against colon carcinogenesis. These results do not support the notion that lysinoalanine or dehydroalanine are a hazard with respect to colon carcinogenicity

Development of the ACTIVE framework to describe stakeholder involvement in systematic reviews

Objectives Involvement of patients, health professionals, and the wider public (‘stakeholders’) is seen to be beneficial to the quality, relevance and impact of research and may enhance the usefulness and uptake of systematic reviews. However, there is a lack of evidence and resources to guide researchers in how to actively involve stakeholders in systematic reviews. In this paper we report the development of the ACTIVE framework to describe how stakeholders are involved in systematic reviews. Methods We developed a framework using methods previously described in the development of conceptual frameworks relating to other areas of public involvement, including: literature searching, data extraction, analysis, and categorisation. A draft ACTIVE framework was developed and then refined after presentation at a conference workshop, before being applied to a series of example systematic reviews. Data extracted from 32 systematic reviews, identified in a systematic scoping review, were categorised against pre-defined constructs, including: who was involved, how stakeholder were recruited, the mode of involvement, at what stage there was involvement and the level of control or influence. Results The final ACTIVE framework described whether patients, carers and/or families, and/or other stakeholders (including health professionals, health decision makers and funders) were involved. We defined: recruitment as either open or closed; the approach to involvement as either onetime, continuous or combined; and the method of involvement as either direct or indirect. The stage of involvement in reviews was defined using the Cochrane Ecosystem stages of a review. The level of control or influence was defined according to the roles and activities of stakeholders in the review process, and described as the ACTIVE continuum of involvement. Conclusions The ACTIVE framework provides a structure with which to describe key components of stakeholder involvement within a systematic review, and we have used this to summarise how stakeholders have been involved in a subset of varied systematic reviews. The ACTIVE continuum of involvement provides a new model that uses tasks and roles to detail the level of stakeholder involvement. This work has contributed to the development of learning resources aimed at supporting systematic review authors and editors to involve stakeholders in their systematic reviews. This framework may support the decision-making of systematic review authors in planning how to involve stakeholders in future review

An EC-Earth coupled atmosphere–ocean single-column model (AOSCM.v1_EC-Earth3) for studying coupled marine and polar processes

Single-column models (SCMs) have been used as tools to help develop numerical weather prediction and global climate models for several decades. SCMs decouple small-scale processes from large-scale forcing, which allows the testing of physical parameterisations in a controlled environment with reduced computational cost. Typically, either the ocean, sea ice or atmosphere is fully modelled and assumptions have to be made regarding the boundary conditions from other subsystems, adding a potential source of error. Here, we present a fully coupled atmosphere–ocean SCM (AOSCM), which is based on the global climate model EC-Earth3. The initial configuration of the AOSCM consists of the Nucleus for European Modelling of the Ocean (NEMO3.6) (ocean), the Louvain-la-Neuve Sea Ice Model (LIM3) (sea ice), the Open Integrated Forecasting System (OpenIFS) cycle 40r1 (atmosphere), and OASIS3-MCT (coupler).Results from the AOSCM are presented at three locations: the tropical Atlantic, the midlatitude Pacific and the Arctic. At all three locations, in situ observations are available for comparison. We find that the coupled AOSCM can capture the observed atmospheric and oceanic evolution based on comparisons with buoy data, soundings and ship-based observations. The model evolution is sensitive to the initial conditions and forcing data imposed on the column. Comparing coupled and uncoupled configurations of the model can help disentangle model feedbacks. We demonstrate that the AOSCM in the current set-up is a valuable tool to advance our understanding in marine and polar boundary layer processes and the interactions between the individual components of the system (atmosphere, sea ice and ocean).</p