Effects of aldosterone on forearm vasculature in treated chronic heart failure

The nongenomic effects of aldosterone in disease states associated with endothelial dysfunction may differ from those in healthy subjects. The effects of locally infused aldosterone on the forearm blood flow and volume were studied in optimally treated patients with chronic heart failure (CHF). At baseline and after incremental intrabrachial aldosterone, forearm blood flow was assessed using conventional strain gouge plethysmography, and forearm venous volume was assessed by radionuclide plethysmography. Constriction of the resistance vasculature of the forearm without significant effect on forearm venous capacitance was demonstrated in response to aldosterone in patients treated for CHF. (C) 2005 by Excerpta Medica Inc.

Body composition in children in remission from acute lymphoblastic leukemia

Background: Changes in body composition are commonly reported in pediatric survivors of acute lymphoblastic leukemia (ALL). However, the effect of ALL and of its treatment on body composition in children in remission from ALL has not been fully examined with the use of a reference method. Objectives: We aimed to determine the body composition and composition of fat-free mass (FFM) in children in remission from ALL. We also aimed to compare the effects that prednisolone and dexamethasone had on the body composition of an ALL survivor population. Design: This cross-sectional study measured height, weight, body volume, total body water, and bone mineral content in 24 children in remission from ALL and 24 age-matched, healthy control subjects. Body composition and FFM composition were evaluated by using the 4-component model. Results: The mean body mass index and fat mass index were significantly (P = 0.05 for both) higher in the ALL survivors than in age-matched control subjects. The composition of the FFM in the 2 treatment groups was not observed to differ significantly. Examination of the composition of FFM made it evident that children in remission from ALL had both significantly greater hydration (P = 0.001) and lower density (P = 0.0001) of FFM than did the control children. Conclusions: Children in remission from ALL may develop excess body fat. To measure body composition accurately in an ALL population, the high hydration and low density of FFM in this population should be taken into consideration.

Development of a non-intrusive system to monitor radial pulse wave velocity

Understanding arterial distensibility has shown to be important in the pathogenesis of cardiovascular abnormalities like hypertension. It is also known that arterial pulse wave velocity (PWV) is a measure of the elasticity or stiffness of peripheral arterial blood vessels. However, it generally requires complex instrumentations to have an accurate measurement and not suited for continual monitoring. In this paper, it describes a simple and non-intrusive method to detect the cardiovascular pulse from a human wrist above the radial artery and a fingertip. The main components of this proposed method are a piezoelectric transducer and a photo-plethysmography circuitry. 5 healthy adults (4 male) with age ranging from 25 to 38 years were recruited. The timing consistency of the detected pulsations is first evaluated and compared to that obtained from a commercial electrocardiogram. Furthermore, the derived PWV is then assessed by the predicted values attained from regression equations of two previous similar studies. The results show good correlations (p < 0.05) and similarities for the former and latter respectively. The simplicity and non-invasive nature of the proposed method can be attractive for even younger or badly disturbed patients. Moreover, it can be used for prolonged monitoring for the comfort of the patients.

A three dimensional surface measurement and reconstruction system for respiratory function analysis

Respiration is a complex activity. If the relationship between all neurological and skeletomuscular interactions was perfectly understood, an accurate dynamic model of the respiratory system could be developed and the interaction between different inputs and outputs could be investigated in a straightforward fashion. Unfortunately, this is not the case and does not appear to be viable at this time. In addition, the provision of appropriate sensor signals for such a model would be a considerable invasive task. Useful quantitative information with respect to respiratory performance can be gained from non-invasive monitoring of chest and abdomen motion. Currently available devices are not well suited in application for spirometric measurement for ambulatory monitoring. A sensor matrix measurement technique is investigated to identify suitable sensing elements with which to base an upper body surface measurement device that monitors respiration. This thesis is divided into two main areas of investigation; model based and geometrical based surface plethysmography. In the first instance, chapter 2 deals with an array of tactile sensors that are used as progression of existing and previously investigated volumetric measurement schemes based on models of respiration. Chapter 3 details a non-model based geometrical approach to surface (and hence volumetric) profile measurement. Later sections of the thesis concentrate upon the development of a functioning prototype sensor array. To broaden the application area the study has been conducted as it would be fore a generically configured sensor array. In experimental form the system performance on group estimation compares favourably with existing system on volumetric performance. In addition provides continuous transient measurement of respiratory motion within an acceptable accuracy using approximately 20 sensing elements. Because of the potential size and complexity of the system it is possible to deploy it as a fully mobile ambulatory monitoring device, which may be used outside of the laboratory. It provides a means by which to isolate coupled physiological functions and thus allows individual contributions to be analysed separately. Thus facilitating greater understanding of respiratory physiology and diagnostic capabilities. The outcome of the study is the basis for a three-dimensional surface contour sensing system that is suitable for respiratory function monitoring and has the prospect with future development to be incorporated into a garment based clinical tool.

Dietary enrichment by almond supplementation: effects on risk factors for cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of death in Europe responsible for more than 4.3 million deaths annually. The World Health Organisation funded the Monica project (1980s-1990s) which monitored ten million subjects aged 22-6Syrs, and demonstrated that coronary heart disease (CHD) mortality declined over 10 years, was due in two thirds of cases to reduced incidence of CHD (reduced risk behaviours e.g. poor diet and smoking) and one third by improved treatments. Epidemiological evidence suggests diets rich in antioxidants decrease incidence of CVD. Regular consumption of nuts, rich in vitamin E and polyphenols reduces atherosclerosis, an important risk for heart disease. Intervention studies to date using alpha tocopherol (an active component of vitamin E) have not consistently proved beneficial. This thesis aims to investigate the effect of almond supplementation on vascular risk factors in healthy young males (18-3Syrs); mature males and female(>SOyrs); and males considered at increased risk of CVD (18-3Syrs) in a cohort of 67 subjects. The effects of almond intake were assessed after 2Sg/d for four weeks followed by SOg/d for four weeks and compared to a control group which did not consume almonds or change their diet. Cardiovascular risk was assessed by plasma lipid profiles, apolipoprotein A1, plasma nitrates/nitrates, vascular flow, BMl, blood pressure, sVCAM-1 and protein oxidation. Systolic and diastolic blood pressures were reduced in almond supplemented volunteers but not in controls. Dietary monounsaturated fatty acids, polyunsaturated fatty acid content and total dietary fats were increased by almond supplementation. Neither sVCAM-1, venous occlusion plethysmography nor plasma nitrite levels were affected by almond intake in any independent group. No significant changes in plasma lipids, and apolipoprotein A1 were observed. In conclusion almonds supplementation caused a reduction in blood pressure that may be due to increased sensitivity of the baroreceptors after increased monounsaturated fatty acid intake.

A comparison of breathing patterns of normal full term infants in supine versus right side-lying during quiet and active behavioral sleep states

This study investigated the effect of sleep position on breathing patterns of normal full term infants during quiet and active behavioral sleep states. Tidal volume, percent contribution of rib cage to tidal volume, and respiration rate were measured via respiratory inductive plethysmography (RIP) and pneumotachograph (PNT) in ten infants sleeping in supine versus right side-lying. Data was collected immediately following two consecutive feedings. Paired t tests and ANOVA comparisons showed no significant differences between the two postures (p $<$.05) in mean tidal volume (supine, M = 19.16, right side, M = 22.45), percent contribution of rib cage to tidal volume (supine, M = 30.55, right side M = 33.20), or respiration rate (supine, M = 49.13, right side, M = 49.37) during quiet sleep. Comparisons also showed no significant differences between the two postures (p $<$.05) in mean tidal volume (supine, M = 18.89, right side, M = 20.12), percent contribution of rib cage to tidal volume (supine, M = 6.43, right side, M = 6.97) or respiration rate (supine, M = 62.18, right side, M = 61.04) during active sleep. Therefore, no differences were found in the three respiratory variables measured between the supine and right side-lying positions. These findings suggest that infants may be positioned in either sleep position without detriment to respiratory function. This information may benefit occupational therapists and other health professionals involved in the education of parents on infant positioning and their respective advantages. ^

Resting energy expenditure, macronutrient utilization, and body composition in term infants after corrective surgery of major congenital anomalies: a case-study

Introduction - Knowledge on the metabolic changes and nutritional needs during the postsurgical anabolic phase in infants is scarce. This analysis explores the associations of resting energy expenditure (REE) and macronutrient utilization with body composition of full-term infants, during catch-up growth after corrective surgery of major congenital anomalies. Methods - A cohort of full-term appropriate for-gestational-age neonates subjected to corrective surgery of major congenital anomalies were recruited after gaining weight for at least one week. REE and macronutrient utilization, measured by respiratory quotient (RQ), were assessed by indirect calorimetry using the Deltatrac II Metabolic Monitor ®. Body composition, expressed as fat-free mass (FFM), fat mass (FM) and adiposity defined as percentage of FM (% FM), was measured by air displacement plethysmography using the Pea Pod ®. Results - Four infants were included at 3 to 5 postnatal weeks. Recommended energy and macronutrient intakes for healthy term infants were provided. Through the study, the median (min-max) REE (Kcal/Kg FFM/d) was 70.8 (60.6-96.1) and RQ was 0.99 (0.72-1.20). Steady increases in both body weight and FFM were associated with initial decrease in FM and adiposity followed by their increase. Low RQ preceded decrease in adiposity. Conclusion - The marked adiposity depletion, not expected during steady weight gain in the postsurgical period, prompts us to report this finding. The subsequent adiposity catch-up was associated with relatively high REE and RQ, suggesting preferential oxidation of carbohydrates and preservation of lipids for fat storage.