Insulin mediated upregulation of the renin angiotensin system in human subcutaneous adipocytes is reduced by Rosiglitazone

Background: Obesity associated hypertension is likely to be due to multiple mechanisms. Identification of the renin-angiotensin system (RAS) within adipose tissue does, however, suggest a potential causal role for it in obesity-associated hypertension. Obese patients are often hyperinsulinaemic, but mechanisms underlying insulin upregulation of the RAS in adipose tissue are unclear. TNFα, an inducer of angiotensinogen in hepatocytes, is elevated in hyperinsulinaemic, obese individuals, and may provide a link in mediating insulin upregulation of the RAS in adipose tissue. Further, thiazolidinediones lower blood pressure in vivo and downregulation of the RAS in adipose tissue may contribute to this effect. We therefore examined the effect of rosiglitazone (RSG), on the insulin mediated upregulation of the RAS. Methods and Results: Sera were obtained from the arterial circulation and from venous blood draining subcutaneous abdominal adipose tissue. Isolated human abdominal subcutaneous adipocytes (n=12) were treated with insulin (1-1000nM) and insulin in combination with RSG (10nM), and RSG (10nM) alone to determine angiotensinogen expression, angiotensin II, bradykinin and TNFα secretion. Subcutaneous adipocytes were also treated with TNFα (10-100ng/mL) to examine the direct effect on angiotensinogen expression and angiotensin II secretion. The findings showed that the arterio-venous difference in angiotensin II levels was significant (↑23%; p<0.001). Insulin increased TNFα secretion in a concentration-dependent manner (p<0.01) whilst RSG (10nM) significantly reduced the insulin mediated rise in TNFα (p<0.001), as well as AGT and angiotensin II. TNFα also increased angiotensinogen and angiotensin II in isolated adipocytes. Conclusions: Our in vivo data suggest that human subcutaneous adipose tissue is a significant source of angiotensin II. This study also demonstrates a potential TNFα mediated mechanism through which insulin may stimulate the RAS and may contribute to explain obesity associated hypertension. RSG downregulates the RAS in subcutaneous adipose tissue and this effect may contribute to the long-term effect of RSG on blood pressure

Conventional, Bayesian, and Modified Prony's methods for characterizing fast and slow waves in equine cancellous bone

Conventional, Bayesian, and the modified least-squares Prony's plus curve-fitting (MLSP + CF) methods were applied to data acquired using 1 MHz center frequency, broadband transducers on a single equine cancellous bone specimen that was systematically shortened from 11.8 mm down to 0.5 mm for a total of 24 sample thicknesses. Due to overlapping fast and slow waves, conventional analysis methods were restricted to data from sample thicknesses ranging from 11.8 mm to 6.0 mm. In contrast, Bayesian and MLSP + CF methods successfully separated fast and slow waves and provided reliable estimates of the ultrasonic properties of fast and slow waves for sample thicknesses ranging from 11.8 mm down to 3.5 mm. Comparisons of the three methods were carried out for phase velocity at the center frequency and the slope of the attenuation coefficient for the fast and slow waves. Good agreement among the three methods was also observed for average signal loss at the center frequency. The Bayesian and MLSP + CF approaches were able to separate the fast and slow waves and provide good estimates of the fast and slow wave properties even when the two wave modes overlapped in both time and frequency domains making conventional analysis methods unreliable

Short-term prospective memory deficits in chronic back pain patients

Objective: Chronic pain, particularly low back pain, is widespread. Although a great deal is known about the impact that this has on quality of life and physical activity, relatively little has been established regarding the more cognitive effects of pain. This study aims to find out whether individuals with chronic pain experience memory deficits in prospective memory (PM), the process of remembering to do things at some future point in time. Examples of PM include remembering to keep an appointment, such as a visit to a clinic, or to perform a particular task, such as paying a bill on time. Methods: The PM of 50 participants with chronic pain was compared with 50 pain-free participants. Each participant completed the Prospective Memory Questionnaire, which assesses three aspects of prospective memory (short-term habitual, long-term episodic, and internally cued), and records the use of strategies to aid remembering. Results: In comparison to those not in pain, participants with chronic pain had significantly impaired short-term prospective memory, an effect which was evident even after co-varying use of analgesics and other drugs. Conclusions: These findings provide new insights into prospective memory dysfunction in people with chronic pain. Possible mechanisms for this dysfunction are discussed and suggestions for future research given

Statistical analysis of climatological data to characterize erosion potential : 1. precipitation events in western Oregon

Periods of precipitation with certain combinations of characteristics (e.g„ high intensity rainfall on saturated soil) can lead to appreciable soil loss in western Oregon. In order to assign realistic probabilities to the occurrence of these periods for use in predicting long-term erosion rates, a soil erosion-specific definition of a precipitation event is applied to more than 31 years of hourly wet season precipitation data from Portland, Salem, and Eugene, Oregon. The values of nine characteristics (duration, magnitude, average intensity, maximum intensity, hours between events, and four measures of antecedent rainfall) that are associated with each event are examined. The statistical analysis of the precipitation event characteristics includes consideration of the marginal distributions and order and return statistics of the individual characteristics as well as joint and conditional distributions of several pairs of characteristics. The order and return statistics provide information about extreme values of individual characteristics, whereas the probabilities of occurrence of some combinations of characteristics are estimated by the joint distributions. Examination of the conditional distributions suggests the types of relationships that exist among the characteristics. The results of these analyses provide general information regarding the types of precipitation events that occur in western Oregon as well as estimates of specific probabilities that are important in the modeling and forecasting of soil erosion in this region.Published October 1984. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Statistical analysis of climatological data to characterize erosion potential: 5. joint precipitation and freezing events in Western Oregon

When precipitation falls on frozen soil, serious soil loss can occur. In order to assign realistic probabilities to the occurrence of this condition for use in predicting erosion rates over long time periods, a technique for combining characteristics of precipitation and air temperature records is applied to more than 31 years of hourly, wet season data from Portland, Salem, and Eugene, Oregon. Periods of overlapping precipitation and freezing air temperature events are combined into clusters and the values of thirteen characteristics that are associated with each cluster are examined. The statistical analysis of the cluster characteristics includes discussions of the marginal distributions and order statistics of the individual characteristics as well as joint distributions of several pairs of characteristics. The order statistics provide information about extreme values of individual characteristics (e.g., minimum temperature) whereas the probabilities of occurrence of certain combinations of characteristics (e.g., precipitation amount and freeze index) are estimated by the joint distributions. The results of these analyses provide information regarding the types of precipitation events that occur in combination with freezing air temperatures in western Oregon as well as estimates of specific probabilities that are important in the modeling and forecasting of soil erosion in this region.Published March 1984. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Statistical analysis of climatological data to characterize erosion potential : 4. freezing events in eastern Oregon/Washington

The occurrence of frozen soil has a major effect on runoff and soil loss in the Pacific Northwest. Hence, information regarding the probabilities of occurrence of periods during which the soil may be frozen is necessary in order to adequately forecast long-term erosion rates for this region. In order to assign realistic probabilities to the occurrence of these periods, a long record of hourly surface air temperature data from Pendleton in eastern Oregon and Walla Walla in eastern Washington are summarized in terms of freezing events. The values of several characteristics of freezing events which may be useful for predicting soil frost occurrence are examined. The statistical analysis of the freezing event characteristics includes consideration of the marginal distributions and order and return statistics of the individual characteristics as well as joint and conditional distributions of several pairs of characteristics. The order and return statistics provide information about extreme values of individual characteristics, whereas the probabilities of occurrence of some combinations of characteristics are estimated by the joint distributions. Examination of the conditional distributions suggests the types of relationships that exist among the characteristics. The results of these analyses provide general information regarding the types of freezing events that occur in eastern Oregon and eastern Washington as well as estimates of specific probabilities that are important in the modeling and forecasting of soil erosion in this region.Published October 1984. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo