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Biomedical subjects

K Casper

Publications and source records attributed to K Casper.

13 recordsLinked to original sources
PubMed1990

Overfeeding: cardiovascular and metabolic response during continuous formula infusion in adult humans.

The cardiovascular and metabolic response to continuous nasoenteric formula infusion was monitored in eight healthy men during three consecutive 1-wk balance periods: maintenance-stabilization, overfeeding at twice the maintenance infusion rate, and postoverfeeding return to maintenance infusion. Elemental balance, thermogenic, and stable-isotope studies carried out throughout protocol identified 1) two distinct phases during overfeeding (early, days 1-4, and late, days 4-7); 2) changes in extracellular fluid (sodium balance) as the major determinant of overfeeding weight gain; 3) individual differences in percentage of excess fuels retained during overfeeding (76-87%), derived from variation in both digestive and thermogenic processes; and 4) a sustained physiologic response during the postoverfeeding period. These initial findings suggest that individuals differ in response to overfeeding and that specific aspects of this variation are amenable to future study. In addition, the timing of observed fluid, metabolic, and cardiovascular changes during overfeeding suggests specific strategies aimed at preventing refeeding circulatory complications.

Adult↗
PubMed1989

Rate of weight loss during underfeeding: relation to level of physical activity.

The kinetics and bioenergetic-metabolic determinants of weight loss were examined in obese women ingesting 900 kcal/d for 5 weeks. The patients were assigned either to a sedentary group (n = 5) or to an exercise group (n = 6) in which the participants expended an additional (X +/- SD) 346 +/- 61 kcal/d in aerobic physical activity. The percentage weight loss and the fractional rates (K1 = fast component; K2 = slow component) of weight loss were almost identical between the two groups. The failure of added exercise to increase the velocity of weight loss could not be explained by differences between the groups in any of the following: gastrointestinal energy and nitrogen (N) absorption; fractional rates of urinary urea N and total N loss; or the thermic effect of the formula diet. The cumulative and fractional rates of protein (ie N) loss were also similar between the groups. The exercise group lost more fat (5.3 +/- 1.0 kg) than the non-exercise group (4.4 +/- 1.6 kg, P less than .001) as measured by underwater weighing. The maximum between-group difference in the rate of fat loss, as determined by energy-N balance, occurred during early underfeeding. With continuation of the 900 kcal/d diet, the between-group differences in the rate of fat loss diminished. The exercise subjects significantly lowered their resting heat losses relative to the non-exercise subjects (P less than .025). This in turn reduced the degree of negative energy balance in the more energy-deficient exercise group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Ethanol: relative fuel value and metabolic effects in vivo.

A nasogastric formula infusion method was used to evaluate the steady-state fuel value of ethanol relative to that of glucose in eight chronically alcoholic men undergoing a 4- or 5-week balance experiment. Each subject received a maintenance infusion of the formula diet throughout the study. When control formula glucose (week 1) was isocalorically replaced with ethanol [week 2, 30% of kcal; week 3 or 4 (5-week experiment) 40% to 60% of kcal], the following was observed: weight loss; zero energy balance and reduced or negative balances of N, K, P, Mg, and Na; increased urinary urea N and 3-methylhistidine; lowered urinary C-peptide; no change in indirectly or directly measured thermal energy losses; and a blood level related rise in breath and urinary ethanol losses. All of these changes promptly reversed during the middle (week 3 in 5-week experiment) and final control weeks. Accounting for all diet-related energy losses (urine, breath, thermal), the fuel value of the ethanol-containing diet relative to the glucose control formula varied between 0.95 and 0.99, depending upon the blood alcohol level. Hence weight loss during short-term (seven-day) ethanol infusion is unrelated to overall negative energy balance, stems primarily from decrements in protein, minerals, and fluid, and may in part be mediated by the reduction in insulin secretion that accompanies switching from dietary glucose to ethanol.

Adult↗
PubMed1989

Congestive heart failure: clinical management by use of continuous nasoenteric feeding.

Congestive heart failure (CHF) is often associated with undernutrition. Although loss of lean tissue may be detrimental to the host, a protective effect is conveyed as cardiac demands are reduced by lower whole-body oxygen consumption (VO2) and circulating fluid volume. The aim of this study was to determine if continuous nasoenteric feeding could promote an anabolic state with increments in lean tissue in moderate-severe CHF patients without adversely effecting cardiac performance. Undernourished CHF patients on a metabolic ward were fed a formula diet infused intragastrically for 2 wk. The energy infusion rate was maintained at 1.4-1.8 X measured resting metabolic rate. During the infusion period, body weight, elemental balances, VO2, and cardiac function (echocardiography) were monitored. Results showed a loss in weight and extracellular fluid, gain in lean body mass (eg, + delta N and delta K), unaltered VO2, and unchanged cardiac function. Cardiac cachexia is therefore safely and effectively manageable by maintenance or repletional levels of nasoenteric feeding.

Body Weight↗
PubMed1988

Continuous nasoenteric feeding: bioenergetic and metabolic response during recovery from semistarvation.

The bioenergetic and metabolic response to continuous nasoenteric feeding was examined under balance conditions for up to 22 d in 12 stable undernourished medical patients. Each subject received a fixed inflow of the mixed-fuel formula at rates of one to three times maintenance energy requirement. The pooled results were used to develop a composite profile of physiologic changes during recovery from semistarvation. Body weight, whole-body gas exchange, minute ventilation, thermal and chemical energy losses, and balances of energy, nitrogen, potassium, and sodium changed as a function of formula infusion rate and duration of feeding. These component measurements allowed calculation of such classic bioenergetic efficiency terms as digestible, metabolizable, and net energy as functions of infused energy (IE, kcal.kg fat free body mass-1.h-1: 0.96IE, 0.93IE, and 6.7 [1 - e-0.16IE], respectively) and the energy content of weight gain (means +/- SD; early, 4.2 +/- 3.5 kcal/g, and later, 7.4 +/- 3.6 kcal/g). Continuous nasoenteric feeding provides a unique opportunity to define previously unexplored dietary and metabolic interrelations in humans.

Adult↗
PubMed1987

Physiologic response and clinical implications of nutrition support.

Cardiopulmonary complications such as sudden death, congestive heart failure and hypercapnia are now recognized to punctuate the refeeding course of malnourished hospitalized patients; these effects in particular occur early in the recovery period. Data that indicate a time-dependent dose and composition effect of continuously infused formula on gas exchange, metabolic rate, ventilation and cardiac-related indexes are discussed. Unlike the interrupted feeding of regular meal ingestion, continuous feeding produces a sustained physiologic response. Delineation of continuous feeding effects on host metabolism provides a rational basis for managing the untoward cardiac and pulmonary complications of nutrition support.

Cardiovascular Physiological Phenomena↗
PubMed1987

Bioenergetic and metabolic response to continuous v intermittent nasoenteric feeding.

Resting thermal energy losses and metabolic balances of N, K, P, Ca, Na, and Mg were compared during continuous and intermittent nasoenteric formula infusion in four healthy men. Each feeding protocol lasted 1 week in a 4-week double crossover experiment. The initial feeding schedule was established randomly. Continuous nasoenteric formula infusion produced no increase in thermal energy losses above the fasting level; energy expenditure fell with sleep to the same extent as with intermittent feeding. Thermal losses were similar during intermittent feeding with the exception of the thermic effect of food that produced an additional average energy loss of 115.7 kcal/d. The total resting and sleeping 24-hour energy expenditure was significantly lower (P less than .01) during continuous formula infusion (means +/- SD for n = 8 balance periods, 1344 +/- 119 kcal) compared to intermittent feeding (1457 +/- 179 kcal). No significant differences in nutrient absorption or balances of N, Na, Ca, and Mg were detected between the two feeding protocols. In contrast, continuous infusion of formula was accompanied by negative balances of K and the cytosolic portion of P; weight balance was slightly negative. Weight, K, and cytosolic P balances were all positive during intermittent feeding (P = NS, less than 0.01, and P less than .05 compared to respective continuous infusion periods). Hence, 1 week of continuous nasogastric formula infusion is associated with similar nutrient absorption, a significant reduction in thermal energy losses, and equivalent protein (N) balance relative to intermittent feeding. Differences in weight balance between the two feeding protocols can be ascribed largely to fluid and mineral shifts. These results suggest that energy requirements are lower during continuous formula infusion by about 100 kcal/d compared to regular meal ingestion.

Adult↗
PubMed1987

Energy expenditure during continuous intragastric infusion of fuel.

Influence of intragastric formula infusion rate on resting thermogenesis was evaluated in 24 healthy subjects. Metabolic rate (M) was measured by indirect calorimetry following an overnight fast. Subgroups then received a continuous intragastric infusion of a formula diet at three levels: submaintenance (mean +/- SEM, 1.02 +/- 0.04 times fasting M, n = 6), maintenance (1.39 +/- 0.01 times fasting M, n = 20), or supramaintenance (2.77 +/- 0.2 times fasting M, n = 14). Formula inflow was started in the evening, and intraprandial M was measured throughout the following day. Relative to fasting, submaintenance and maintenance infusions produced no detectable change in M. With supramaintenance infusion, M increased significantly (10.1%, p less than 0.05) above fasting level. Hence during continuous formula infusion a rise in M above fasting occurs only when rate of energy infusion exceeds rate of thermal energy losses. These results have implications in regard to energetic efficiency of continuous fuel infusion relative to intermittent food or formula ingestion.

Adult↗
PubMedDate not supplied

Application of electromagnetic and sound waves in nutritional assessment.

Four relatively new techniques that apply electromagnetic or sound waves promise to play a major role in the study of human body composition and in clinical nutritional assessment. Computerized axial tomography, nuclear magnetic resonance, infrared interactance, and ultrasonography provide capabilities for measuring the following: total body and regional fat volume; regional skeletal muscle volume; brain, liver, kidney, heart, spleen, and tumor volume; lean tissue content of triglyceride, iron, and high-energy intermediates; bone density; and cardiac function. Each method is reviewed with regard to basic principles, research and clinical applications, strengths, and limitations.

Carbon Isotopes↗
PubMedDate not supplied

Continuous nasoenteral feeding: inverse relation between infusion rate and serum levels of bilirubin.

The relation between nasoenteric formula caloric infusion rate and the serum bilirubin level was examined in 15 healthy subjects. The study protocol spanned 3 days and included fasting studies on day 1, continuous maintenance nasogastric feeding of a formula diet on day 2, and continuous feeding at a rate twice the maintenance level on day 3. Blood studies were performed in the early morning of each day. Fifteen subjects underwent the fasting measurements and the maintenance infusion, while 11 underwent all 3 days of the protocol. With the maintenance infusion serum bilirubin fell from the fasting value of (X +/- SD) 0.77 +/- 0.53 to 0.63 +/- 0.49 mg/dl for a reduction of 18% (p less than 0.05). For the subgroup of 11 subjects receiving two levels of formula infusion, fasting and maintenance serum bilirubin levels were 0.81 +/- 0.57 and 0.65 +/- 0.47 mg/dl, respectively, (p less than 0.05). With the twice maintenance infusion the plasma bilirubin decreased further to 0.46 +/- 0.29 mg/dl, a decrement of 43% relative to fasting (p less than 0.01). No other significant changes were detected during the protocol in the standard blood chemical and hematologic studies. Thus, the serum level of bilirubin is inversely related to the formula caloric infusion rate during continuous nasoenteric feeding.

Adult↗
PubMedDate not supplied

Fiber supplementation of enteral formulas: effects on the bioavailability of major nutrients and gastrointestinal tolerance.

Two fiber-supplemented enteral formulas were recently introduced for patient application, Susta II and Enrich (12.4-g and 38.5-g soy polysaccharide/2000 kcal, respectively). This investigation had a 3-fold purpose: to determine if and to what extent fiber-supplementation changes the chemical composition of stool relative to a fiber-free formula (Ensure); to establish the clinical tolerance of the two new formulas; and to quantify the effects of soy polysaccharide on nutrient bioavailability. The study was conducted in two consecutive phases: A (n = 6 subjects; random assignment to either Ensure or Susta II for 1-2 weeks followed by isocaloric cross-over to the alternate formula for an equal period of time) and B (n = 8 subjects evaluated as in phase A except Enrich replaced Ensure). Each balance week consisted of clinical/subjective monitoring, evaluation of stool composition (H2O and dry weight), apparent nutrient absorption (energy, fat, N, P, K, Ca, Mg, Zn, Na, and Cl), and metabolic balance (N, P, K, Ca, Mg, Na, and Cl). Relative to the fiber-free formula the two fiber-supplemented solutions produced increases in fecal N, fat, H2O, and minerals of variable magnitude; there were corresponding reductions in net absorption of organic compounds and minerals. The additional minerals added to the fiber-supplemented formulas and the minimal effects on N absorption preserved balance; the retention of N, P, K, Ca, Mg, Na, and Cl were similar for all three formulas. No adverse clinical effects of the fiber-supplemented formulas were noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗