Irregular Satellites of the Planets: Products of Capture in the Early Solar System

All four giant planets in the Solar system possess irregular satellites, characterized by large, highly eccentric and/or inclined orbits that are distinct from the nearly circular, uninclined orbits of the regular satellites. This difference can be traced directly to different modes of formation. Whereas the regular satellites grew by accretion within circumplanetary disks the irregular satellites were captured from initially heliocentric orbits at an early epoch. Recently, powerful survey observations have greatly increased the number of known irregular satellites, permitting a fresh look at the group properties of these objects and motivating a re-examination of the mechanisms of capture. None of the suggested mechanisms, including gas-drag, pull-down, and three-body capture, convincingly fit the group characteristics of the irregular satellites. The sources of the satellites also remain unidentified.Comment: 51 pages, 17 figures, 5 tables, to appear in ARAA 200

Dopamine, appetitive reinforcement, and the neuropsychology of human learning: An individual differences approach

Personality research is usually perceived as lying towards the “softer” end of psychological inquiry, seemingly far from the “harder” neural mechanisms, processes, and neurological lesions which are the daily stuff of neuropsychology. As biologically-oriented personality psychologists, however, we have always tried to couch our proposals in brain- behavioural terms and have even offered suggestions as to the “neuropsychology” of personality traits such as anxiety and their related clinical conditions (e.g., Gray, 1982). Furthermore, several other personality theorists have also drawn from the rich materials of behavioural neuroscience (e.g., Cloninger, Svracik, & Przybeck, 1993; Depue & Collins, 1999; Zuckerman, 1991). In this chapter we continue to apply our neuropsychological approach to personality: specifically focusing on the effects of personality traits on learning tasks

Genes responsive to rapamycin and serum deprivation are clustered on chromosomes and undergo re-organization within local chromatin environments.

Supplementary materials are available at University of Toronto: https://tspace.library.utoronto.ca/handle/1807/9982

Low correlation between visit-to-visit variability and 24-h variability of blood pressure

Visit-to-visit variability (VVV) of clinic systolic blood pressure (SBP) has been associated with cardiovascular disease risk. Given the need for obtaining blood pressure (BP) at multiple visits to calculate VVV, substituting BP variability from ambulatory blood pressure monitoring (ABPM) may be a practical alternative. We assessed the correlation between VVV of BP and BP variability from ABPM using data from 146 untreated, mostly normotensive participants (mean age 47.9 years) in a substudy of the ongoing Masked Hypertension Study. VVV of SBP and diastolic blood pressure (DBP) was estimated by the standard deviation (SDvvv) and average real variability (ARVvvv) from 6 study visits over a median of 216 days. ABPM data were used to calculate the day-night SD (SDdn) and the ARV of SBP and DBP over 24 hours (ARV24). For SBP, the mean SDvvv and SDdn were 6.3 (SD=2.5) and 8.8 (SD=1.8) mmHg, respectively, and mean ARVvvv and ARV24 were 7.2 (SD=3.2) and 8.4 (SD=2.1) mmHg, respectively. The Spearman correlation coefficient between SDvvv and SDdn of SBP was rs=0.25 and between ARVvvv and ARV24 was rs=0.17. Participants in the highest quartile of SDdn of SBP were 1.66 (95% CI: 0.93 – 2.75) times more likely to be in the highest quartile of SDvvv of SBP. The observed-to-expected ratio between the highest quartiles of ARVvvv and ARV24 of SBP was 0.89 (95% CI: 0.41 – 1.69). The correlations for SDvvv and SDdn and ARVvvv and ARV24 of DBP were minimal. These data suggest VVV and 24-hour variability are weakly correlated and not interchangeable

Favorable patient acceptance of ambulatory blood pressure monitoring in a primary care setting in the United States: a cross-sectional survey

BACKGROUND: The use of ambulatory blood pressure monitoring (ABPM) in the diagnosis and management of hypertension in primary care settings in the United States is increasing. Insufficient information is available describing patients' experiences and acceptance of this technology in the United States, where medical insurance coverage of the procedure is often limited. The objective of this study was to describe patient satisfaction with ABPM performed in a primary care office in the United States, using modern ABPM technology. METHODS: Cross-sectional survey performed on consecutive patients referred to the ABPM service of the Family Care Center, University of Iowa Hospitals and Clinics, Iowa City, Iowa from January 2001 to July 2003. Measures of patient satisfaction and acceptance with the device, comfort, and overall session were assessed via a 9-question, Likert-scale response survey. RESULTS: Since its inception two and a half years ago, 245 total ABPM sessions have been conducted in 235 unique patients. Of the 235 eligible respondents, 177 returned completed surveys, yielding a 75% response rate. Three-fourths (75%) of patients believed that undergoing the test was worthwhile considering the time and monetary cost involved, while most (90%) reported they thought the information provided by the test would be helpful to their physician in making treatment decisions. Patients reporting that their physician had clearly explained the benefit of undergoing the testing were more likely to report that they thought the results of the test would be more helpful in making treatment decisions. Few patients (20%) found that wearing the monitor was uncomfortable. CONCLUSIONS: When clinically indicated, clinicians should not hesitate to order ABPM testing for fear of subjecting patients to an uncomfortable test, or an uncovered insurance benefit. When ordering ABPM, they should be sure to educate the patient about the potential benefits of undergoing the testing. Most patients believe the test will provide useful information in making treatment decisions, despite probable lack of insurance coverage, and appear willing to experience some discomfort for the overall gain of the results obtained from undergoing the session

Acute kidney disease and renal recovery : consensus report of the Acute Disease Quality Initiative (ADQI) 16 Workgroup

Consensus definitions have been reached for both acute kidney injury (AKI) and chronic kidney disease (CKD) and these definitions are now routinely used in research and clinical practice. The KDIGO guideline defines AKI as an abrupt decrease in kidney function occurring over 7 days or less, whereas CKD is defined by the persistence of kidney disease for a period of > 90 days. AKI and CKD are increasingly recognized as related entities and in some instances probably represent a continuum of the disease process. For patients in whom pathophysiologic processes are ongoing, the term acute kidney disease (AKD) has been proposed to define the course of disease after AKI; however, definitions of AKD and strategies for the management of patients with AKD are not currently available. In this consensus statement, the Acute Disease Quality Initiative (ADQI) proposes definitions, staging criteria for AKD, and strategies for the management of affected patients. We also make recommendations for areas of future research, which aim to improve understanding of the underlying processes and improve outcomes for patients with AKD

The Blood Pressure "Uncertainty Range" – a pragmatic approach to overcome current diagnostic uncertainties (II)

A tremendous amount of scientific evidence regarding the physiology and physiopathology of high blood pressure combined with a sophisticated therapeutic arsenal is at the disposal of the medical community to counteract the overall public health burden of hypertension. Ample evidence has also been gathered from a multitude of large-scale randomized trials indicating the beneficial effects of current treatment strategies in terms of reduced hypertension-related morbidity and mortality. In spite of these impressive advances and, deeply disappointingly from a public health perspective, the real picture of hypertension management is overshadowed by widespread diagnostic inaccuracies (underdiagnosis, overdiagnosis) as well as by treatment failures generated by undertreatment, overtreatment, and misuse of medications. The scientific, medical and patient communities as well as decision-makers worldwide are striving for greatest possible health gains from available resources. A seemingly well-crystallised reasoning is that comprehensive strategic approaches must not only target hypertension as a pathological entity, but rather, take into account the wider environment in which hypertension is a major risk factor for cardiovascular disease carrying a great deal of our inheritance, and its interplay in the constellation of other, well-known, modifiable risk factors, i.e., attention is to be switched from one's "blood pressure level" to one's absolute cardiovascular risk and its determinants. Likewise, a risk/benefit assessment in each individual case is required in order to achieve best possible results. Nevertheless, it is of paramount importance to insure generalizability of ABPM use in clinical practice with the aim of improving the accuracy of a first diagnosis for both individual treatment and clinical research purposes. Widespread adoption of the method requires quick adjustment of current guidelines, development of appropriate technology infrastructure and training of staff (i.e., education, decision support, and information systems for practitioners and patients). Progress can be achieved in a few years, or in the next 25 years

Cognitive and autonomic dysfunction measures in normal controls, white coat and borderline hypertension

<p>Abstract</p> <p>Background</p> <p>White coat hypertension (WCHT) is a significant clinical condition with haemodynamic differences and presence of functional changes. We aim to compare cognitive and autonomic dysfunction variables (heart rate variability) between subjects with normal blood pressure (controls), WCHT, and borderline hypertension (BLH).</p> <p>Methods</p> <p>We performed a cross-sectional study in a cohort of 69 subjects (mean age ± SD; 38.2 ±10.8 years) comprising comparable number of normal controls, WCHT, and BLH. We measured clinic and 24-hour ambulatory blood pressure monitoring (ABPM), cognitive function parameters, and heart rate variability (HRV). All subjects underwent 24-hour ambulatory electrocardiography monitoring which was analyzed for HRV measurements. We performed a routine echocardiography (ECHO) for all subjects.</p> <p>Results</p> <p>Multiple comparison between the three groups revealed significant (p < 0.04) differences in mean day-time ABPM (systolic and diastolic). In the state anxiety inventory (SAI), both subjects with WCHT and BLH had significantly (p < 0.006) higher anxiety levels than the control group. In memory tasks WCHT subjects scored significantly (p < 0.004) lower in comparison with the other two groups. WCHT significantly (p < 0.001) performed less in memory tests, whereas BLH subjects had significantly (p < 0.001) lower reaction time. We found a significant (p < 0.05) difference in the 24-hour RMSSD and SDNN between the three groups. There was significant correlation between 24-hour RMSSD and computer CANTAB scores. The Echocardiography assessment revealed no significant differences in LV mass indices and diastolic function.</p> <p>Conclusions</p> <p>WCHT and BLH subjects showed lower cognitive performance and higher levels of anxiety when compared to controls. Autonomic function reflected by HRV indices was lower in WCHT and BLH in contrast to control, though not significantly. Our results suggest that WCHT may not be a benign condition as it may contribute to the overall risk for cardiovascular disease and LV damage. Longitudinal studies of patients with WCHT should clarify the transient, persistent or the progressive nature of this condition.</p

Peripheral arterial volume distensibility changes with applied external pressure: significant difference between arteries with different compliance

This study aimed to quantify the different effect of external cuff pressure on arterial volume distensibility between peripheral arteries with different compliance. 30 healthy subjects were studied with the arm at two positions (0° and 45° from the horizontal level) to introduce different compliance of arteries. The electrocardiogram and finger and ear photoplethysmograms were recorded simultaneously under five external cuff pressures (0, 10, 20, 30 and 40 mmHg) on the whole arm to obtain arterial volume distensibility. With the applied external cuff pressures of 10, 20, 30 and 40 mmHg, the overall changes in arterial volume distensibility referred to those without external pressure were 0.010, 0.029, 0.054 and 0.108% per mmHg for the arm at the horizontal level, and 0.026, 0.071, 0.170 and 0.389% per mmHg for the arm at 45° from the horizontal level, confirming the non-linearity between arterial volume distensibility and external pressure. More interestingly, the significant differences in arterial volume distensibility changes were observed between the two arm positions, which were 0.016, 0.043, 0.116 and 0.281% per mmHg (all P < 0.01). Our findings demonstrated that arterial volume distensibility of peripheral arm arteries increased with external pressure, with a greater effect for more compliant arteries