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Biomedical subjects

R N Pierson

Publications and source records attributed to R N Pierson.

At least 199 records · Page 11Linked to original sources
PubMed1977

Radiocardiography in clinical cardiology.

Quantitative radiocardiography provides a variety of noninvasive measurements of value in cardiology. A gamma camera and computer processing are required for most of these measurements. The advantages of ease, economy, and safety of these procedures are, in part, offset by the complexity of as yet unstandaridized methods and incomplete validation of results. The expansion of these techniques will inevitably be rapid. Their careful performance requires, for the moment, a major and perhaps dedicated effort by at least one member of the professional team, if the pitfalls that lead to unrecognized error are to be avoided. We may anticipate more automated and reliable results with increased experience and validation.

Heart Aneurysm↗
PubMed1976

Disparate hydration of adipose and lean tissue require a new model for body water distribution in man.

The intra and extracellular fluid spaces in adipose tissue were determined by by 3H2O, 82Br-(minus), and 35SO4= uptake, and by appropriate chemical methods, in surgical biopsy material from 16 patients undergoing elective laparatomy. Total water space for adipose tissue was 14 +/- 1.4%: extracellular component was 11 +/- 1.1% in mesenteric and subcutaneous depots. Use of these adipose tissue hydration constants, combined with measurements of total body water (TBW), extracellular water (ECW), total body potassium, and experimentally derived age-specific constants for lean body potassium content, permits development of a four compartment model for body water which considers intra and extracellular components separately for adipose (AT) and adipose-free (AFM) tissue masses. This model has the form (see journal) where x is the total hydration and y the extracellular hydration of the adipose-free mass. The equations can be solved for the ECW and ICW of the adipose-free mass, defined by its potassium content. In four normal subjects, x was measured as 0.80 +/- 0.032, and y as 0.24 +/- 0.017. Thus, the adipose free mass, compared with adipose tissue, has approximately six times the total water and twice the extracellular water content per unit weight.

Adipose Tissue↗
PubMed1976

The assessment of human body composition during weight reduction: evaluation of a new model for clinical studies.

Adipose tissue, the logical target component in weight reduction regimens, was measured in five obese subjects during weight reduction, and in four normal weight controls. The two compartment model of Ljunggren, consisting of adipose tissue (AT) and adipose tissue-free mass (AFM), was further developed by finding experimental values for total water, extracellular water (ECW), lipid, and cell solids in 16 biopsied subjects. The AFM was estimated from body potassium content (40K counting) by use of an age/sex specific constant for the K content in the fat free body. Five obese subjects maintained for 46 days on regimens averaging 800 kcal/day had initial AT from 48% to 60% of body weight compared with AT 27% to 46% in four normal controls. Weight reductions averaged 17.4 kg (12% of initial weight), with approximately equal reductions in adipose tissue, adipose-free mass, and water. Initial fluid compartment ratios in the obese were unusually high (ECW:ICW in AFM was 0.74 +/- 0.23 [S.D.] compared with 0.42 +/- 0.05 in normals); these values returned toward normal (to 0.59 +/- 0.06) with weight reduction. The fact that it was possible to disclose a hitherto unappreciated abnormality of hydration in the adipose-free mass of obese subjects and its change toward normal with weight reduction, suggests that the adipose:adipose-free model may have a special utility when body composition measurements are used to monitor the effects of weight reduction regimens on various body constituents.

Adipose Tissue↗
PubMed1975

Determination of the bromide space in man by fluorescent excitation analysis of oral bromine.

The bromide dilutional volume determined by intravenous administration of 82Br has been compared with the corresponding volume determined by oral administration of stable bromide in 11 patients with various medical disorders. Stable bromide was assayed by fluorescent excitation analysis using a 109Cd source and a lithium-drifted silicon detector. The average deviation between the fluorescent and the radiobromide dilutional volumes was 4.2% with a standard deviation of +/- 8.5%. This substantiates both the accuracy of the fluorescent excitation method as applied to this tracer and the validity of utilizing oral tracer administration in comparison with intravenous administration. The derived estimates of extracellular fluid volume averaged 28.7% of body weight in the entire group of 11 patients and 25.8% in the 4 normal subjects included in the group. Evaluation of the extracellular fluid space utilizing fluorescent excitation of stable bromide permits high statistical accuracy of sample measurement with great simplicity compared with current chemical methods and with avoidance of the patient radiation exposure associated with 82Br.

Administration, Oral↗
PubMed1975

Distribution of zinc in skeletal muscle and liver tissue in normal and dietary controlled alcoholic rats.

Zinc deficiency is a concomitant of both alcoholism and cirrhosis, as indicated by plasma and tissue measurements in man. The intracellular sites of zinc distribution, the site-specific nature of alcohol/cirrhosis-related depletion, and the alcohol exposure-zinc depletion time function have not been reported. Spague-Dawley rats (16) at 5 to 6 weeks were given normal chow and 20 per cent ethanol as sole water source. Control animals (14) had tap water. In rats killed at 2, 5, 9, and 14 weeks, zinc levels were measured by atomic absorption spectroscopy in plasma (p); muscle tissue (MT), cell sap (MCS) cell sap-free (MCSF), and mitochondria (MM); liver tissue (LT), cell sap (MCS), cell sap-free fraction (LCSF), And mitochondria (LM). Control zinc levels were stable in all tissues over the 14-week study; p = 108, plus or minus 10 mug per 100 ml., MT = 125 plus or minus 18, MCS = 30.3 plus or minus 3, MCSF = 70 plus or minus 6, MM = 209 plus or minus 17, LT = 198 plus or minus 29, LCS = 125 plus or minus 11.0, LCSF = 79.5 plus or minus 11.2, and LM = 291 plus or minus 30 mug per gram of dry tissue. Ethanol-fed rats showed marked decrease in all liver zinc fractions from the earliest (2 weeks) time, with the greatest depletion in LM to 35 per cent of control. MT and p zinc showed monotonic gradual declines at the rate of 3 per cent per week, becoming statistically different from control at 9 weeks in both tissues. Normal weight gain occurred in control animals: alcohol rats gained 52 per cent of control to 5 weeks, and showed no subsequent gain, weighing 62 per cent of control levels at 14 weeks. Liver mitochondria contain the highest zinc concentration, and are most rapidly depleted. MT and p declines follow hepatic zinc loss.

Alcoholism↗