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R N Pierson

Publications and source records attributed to R N Pierson.

215 records · Page 12Linked to original sources
PubMedDate not supplied

Hyperacute rejection is attenuated in GalT knockout swine lungs perfused ex vivo with human blood.

BACKGROUND: Hyperacute rejection (HAR) is one of the principal obstacles to successful xenotransplantation. Homozygous alpha-1,3-galactosyltransferase knockout (GalT-KO) miniature swine now offer the prospect of overcoming this barrier to xenotransplantation. In this study, the short-term function of GalT-KO swine lungs was evaluated in a well-established ex vivo model of swine-to-human lung xenotransplantation. METHODS: Lungs from homozygous GalT-KO swine (n = 3) and control lungs from pigs of the background strain used to create the GalT-KO pig line (n = 2) were perfused ex vivo with freshly collected heparinized human blood. Graft function was assessed by various physiologic measurements, serial histologic and immunohistochemical evaluation, and assays of complement and platelet activation. RESULTS: Xenoperfused control swine lungs exhibited HAR with graft survival times <5 minutes. In contrast, GalT-KO swine lungs retained their function for approximately 2 hours, on average. GalT-KO swine lungs showed decreased complement and platelet activation compared with controls. Nonetheless, activation of complement and coagulation cascades was not completely eliminated in the GalT-KO swine lungs. CONCLUSIONS: The survival of xenoperfused GalT-KO swine lungs was significantly prolonged, as compared with control lungs expressing Gal. This appears to have been due largely to substantially reduced complement activation. Nonetheless, the xenoperfused GalT-KO lungs still showed some evidence of complement fixation and intravascular coagulopathy by the time of graft demise.

Acute Disease↗
PubMedDate not supplied

Body-size corrections for in vivo neutron activation analysis.

Differences in body size and shape can cause large variances in the results of in vivo neutron activation analysis. Preliminary body-size correction data were obtained for the delayed-gamma neutron activation facility (DGNA) at Brookhaven National Laboratory (BNL), based on phantom standards of different sizes, used in combination with computer simulations on the effect of different body sizes.

Body Composition↗
PubMedDate not supplied

The relative contribution of body fat and fat pattern to blood pressure level.

Although the association between body weight and blood pressure is irrefutable, body fat mass and blood pressure level may not necessarily be directly related. To clarify the relative contribution of fat mass to blood pressure level, we analyzed data on 399 adults consecutively entering a weight control program. Although most subjects were notably overweight (mean ideal body weight 177%), the population represented a wide spectrum of body weights and blood pressure levels. Study parameters included body fat mass (by total body water, 40K, and Steinkamp formula), lean body mass, body build (chest to height ratio), fat cell number and size from bilateral buttock biopsy specimens, upper fat pattern by arm to thigh circumference ratio, and central fat pattern by subscapular to triceps skinfold ratio. Our results concurred with previously noted correlations between obesity and blood pressure (as mean arterial pressure): weight (r = 0.44), percentage of body fat (r = 0.19), and absolute fat mass (r = 0.38; all p less than 0.01); however, lean body mass, age, and body build correlated highly with both fat mass and mean arterial pressure, thereby confounding this relationship. Multivariate analysis was performed to evaluate the relative contribution of fat mass to mean arterial pressure in the presence of these and other potentially confounding variables. Lean body mass, age, body build, and an upper body fat pattern were found to contribute significantly to the variation in mean arterial pressure (p less than 0.01). In their presence, percentage of body fat, absolute fat mass, central fat pattern, fat cell characteristics, and age of onset of obesity did not significantly improve the predictability of mean arterial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMedDate not supplied

Time-dependent variation in weight and body composition in healthy adults.

OBJECTIVES: To define the limits of change in body weight and body composition after different time intervals in healthy, normal adults. METHODS: Prospective and retrospective analyses of paired body composition studies in a total of 326 healthy adults, ages 18 to 97. Measurements included body weight, fat and fat-free mass (FFM) by dual x-ray absorptiometry (DXA) and bioimpedance analysis (BIA), plus body cell mass (BCM) by whole-body counting of 40K and BIA. RESULTS: Time interval between studies was a significant predictor of the differences in paired studies. The 95% confidence intervals for percent difference were lowest for body weight, intermediate for BCM and FFM, and highest for fat, in part because of the differences in sizes of these body compartments. There were significant associations among the changes in body composition by BIA and by criterion methods, suggesting that the observed changes are real. CONCLUSIONS: The normal variation in body weight and body composition increases over time. Time-dependent criteria may increase the sensitivity in diagnosing malnutrition. Interpreting changes in body compartments requires consideration of the size of each compartment.

Absorptiometry, Photon↗
PubMedDate not supplied

Effect of home total parenteral nutrition on body composition in patients with acquired immunodeficiency syndrome.

Malnutrition occurs commonly in patients with acquired immunodeficiency syndrome (AIDS). The efficacy of nutritional support is unknown. A prospective, longitudinal study was conducted to determine the effect of prolonged total parenteral nutrition on body composition in 12 AIDS patients. Five patients were malnourished because of problems with food intake or absorption, while seven had systemic infections, with or without a malabsorption syndrome. The AIDS patients gained body weight and body fat content in response to total parenteral nutrition, while mean body cell mass, estimated as total body potassium content, was unchanged. However, all five patients with altered intake or absorption had significant repletion of body cell mass which was significantly different from the patients with systemic infections. Calorie and nitrogen intake did not differ between the two groups. It is concluded that body mass repletion is possible in AIDS patients in whom malabsorption is the major pathogenetic factor in producing malnutrition and is less successful in patients with serious ongoing systemic diseases. Thus, the response to nutritional support is dependent on the particular clinical circumstances.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Validation of bioimpedance analysis as a measure of change in body cell mass as estimated by whole-body counting of potassium in adults.

BACKGROUND: The body cell mass (BCM) is an important measure of macronutrient status, but measurements are difficult to obtain outside of sophisticated research laboratories. Bioimpedance analysis (BIA) is a simple technique that holds promise as a means of estimating body composition. The purpose of this study was to evaluate the ability of BIA to estimate changes in BCM as measured by whole body counting of 40K (TBK). METHODS: Paired studies of BCM, including both TBK and BIA, were compared in 87 human immunodeficiency virus-positive subjects and in 62 healthy, weight-stable control adults. Potential errors in the predictions were examined. RESULTS: BCM change by TBK and BIA correlated closely (r = .755). After accounting for errors related to repeat measures of TBK, the correlation coefficient was .784, with a standard error of the estimate of 1.24 kg. The differences between predicted and measured BCM change were consistent with a normal distribution. However, there was a systematic error in prediction, with BIA underpredicting the magnitudes of both gains and losses in BCM by TBK. CONCLUSIONS: BIA is a useful surrogate for measuring changes in BCM in clinical circumstances. Because TBK assesses only intracellular potassium, whereas BIA reflects all intracellular cations, the underprediction of BCM change by BIA compared with TBK could be related to changes in intracellular potassium concentration as a result of malnutrition or its treatment.

Adult↗