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Biomedical subjects

J L Mullen

Publications and source records attributed to J L Mullen.

At least 55 records · Page 3Linked to original sources
PubMed1988

Calorie-nitrogen interactions in the parenterally fed primate.

To test the hypothesis that nonprotein calorie intake and nitrogen intake are equally important in establishing positive nitrogen balance, weight gain, and serum protein response in the depleted primate treated with total parenteral nutrition (TPN), 10 adult male chair-adapted primates (Macaque fascicularis) were studied. After 10 days of nutritional depletion (nothing by mouth; 5% dextrose with electrolytes administered intravenously) animals were randomized to receive one of four TPN diets for 10 days. The depletion/repletion cycle was repeated, after 1 month of caged free feeding, until all animals had received the four TPN diets. Two levels of nonprotein caloric intake (155% and 100% of primate resting energy expenditure) and two levels of nitrogen intake (200% and 100% of primate nitrogen requirement) were used to make the four different diets. Nitrogen balance (p = 0.01) and serum total iron-binding capacity response (p = 0.02) were significantly influenced by the level of nitrogen intake but not by nonprotein calorie intake, which significantly influenced only weight gain (p = 0.03). Fluid balance was not significantly different for any diet. Fat and protein stores may be selectively repleted in this model by adjusting the nonprotein calorie and nitrogen content of TPN.

Animals↗
PubMed1987

Caloric requirements in total parenteral nutrition.

Resting energy expenditure (REE) was measured in 100 consecutive total parenteral nutrition (TPN) patients. Only forty-eight percent of the measured REEs were within 90-110% of the predicted Harris-Benedict values. A literature review revealed 191 published guidelines for non-protein caloric requirements of hospitalized TPN patients. These guidelines were appropriately matched and applied to the 100 individual TPN patients. The relationship between the recommended caloric supply and measured caloric expenditure was minimal. The recommendations exceeded measured REE by an average of 1076 +/- 660 kcal/day. These published guidelines were substantially above and below caloric requirements based on measured REE for both fat maintained (130% REE) and fat depleted (150% REE) patients. Following published guidelines rather than standards based on measured REE results in the administration of 6947 excess liters of TPN per year. Improvement in the precision of TPN caloric prescription can be accomplished by using measured REE as a reference base. When published guidelines were compared to prescriptions based on measured REE it was found that published guidelines were inaccurate both overall and individually and a substantial cost savings justifies actual measurement of energy needs.

Adipose Tissue↗
PubMed1987

Parenteral (glucose or glucose-lipid) vs enteral repletion in malnourished primates: a controlled crossover study.

Nutritional repletion with glucose-based total parenteral nutrition (TPN), mixed-substrate (58% lipid, 42% glucose) TPN, and mixed-substrate total enteral nutrition (TEN) was studied in four adult male chair-adapted primates using a crossover design. After 10 d nutritional depletion animals were repleted for 10 d with one of three isocaloric isonitrogenous diets. TPN Diets I and II were identical except that I provided all nonprotein calories as glucose while II provided 58% nonprotein calories as lipid and 42% as glucose. Animals were randomized to I or II as their first repletion treatment. The 20-d depletion-repletion cycle was repeated with the other TPN diet after a 30-d rest period of caged free-feeding. After another 30-d rest period, animals underwent a third 10-d depletion and were repleted with 10 d of TEN (Diet III, identical to II in composition). The three diets resulted in similar weight gain, positive nitrogen balance and fluid balance, and increase in total iron-binding capacity.

Animals↗
PubMed1986

Alterations in exogenous substrate metabolism in sepsis.

Metabolic rates and substrate utilization patterns were evaluated by using a rate cecal ligation and perforation model. Animals that survived for 48 hours after the induction of sepsis were hypermetabolic and responded appropriately to varying exogenous substrate infusions. In contrast, animals that did not survive to 48 hours were premorbidly hypometabolic and failed to adjust their oxidation patterns in response to the exogenous substrate supply. These findings suggest the benefit of individually tailoring the supply of exogenous nutrients in critically ill patients with sepsis and of frequent reassessment of metabolic parameters, including the resting energy expenditure and respiratory quotient.

Animals↗
PubMed1986

Energy expenditure in malnourished patients with colorectal cancer.

To evaluate energy expenditure in patients who have colorectal cancer with varying stages of disease and to examine the possible determinants of energy expenditure in a group of patients with cancer who have the same type of tumor, we studied 73 patients with biopsy proven and pathologically staged adenocarcinomas of the colon and rectum. Resting energy expenditure (REE) was measured by indirect calorimetry and compared with predicted energy expenditure (PEE), which was calculated from the Harris-Benedict formulas. Nutritional and tumor characteristics were examined. Forty-nine percent of patients had abnormal REE (normal = PEE +/- 10%). One quarter of the patients were hypometabolic (REE less than 90% PEE). The abnormalities persisted despite normalization of REE to metabolic body size (kg0.75) or predicted values based on weight, height, age, and sex. There were no differences in nutritional status, as judged by the percent of weight loss and visceral protein levels, between those patients in the hypometabolic, normometabolic, or hypermetabolic categories, and there were no significant relationships between energy expenditure and the tumor burden. The mean duration of disease in the normometabolic group was 4.5 months, while the hypometabolic and hypermetabolic groups had mean durations of 9.5 and 14.2 months, respectively. The tumor site and duration of the disease are important variables in studies of energy expenditure in patients with cancer.

Adenocarcinoma↗
PubMed1986

Nutritional support of the cancer patient: delivery systems and formulations.

Safe, efficacious nutritional support of cancer patients requires a complete assessment to determine each patient's fluid, protein, energy, and micronutrient requirements. The authors review the growing variety of enteral and parenteral formulas and access routes available to provide an individualized nutrient prescription, emphasizing new techniques, their specific indications, and complications.

Cachexia↗
PubMed1986

The relationship of serum cholesterol and vitamin A in hospitalized patients with and without cancer.

Interrelationships among circulating levels of cholesterol, vitamin A, and selected transport proteins, as well as other nutritional variables were examined in a large population of hospitalized cancer (CA, n = 94) and noncancer (NONCA, n = 432) patients in order to help clarify a relationship between serum cholesterol and vitamin A. Serum cholesterol and vitamin A levels were positively correlated (r = 0.39; p less than 0.001) in both CA and NONCA groups. One hypothesis that might explain such a relationship was investigated. Results suggest that serum-transport protein levels and nutritional status are important factors that lead to a correlation between serum cholesterol and vitamin A by virtue of their mutual associations with both substances. Results suggest also that NONCA patients may have a more complex relationship of variates to serum-vitamin A levels than CA patients and that low levels of both cholesterol and vitamin A in CA patients may be related more to nutritional status than to the presence of cancer.

Aged↗
PubMed1986

Net protein anabolism with hypocaloric parenteral nutrition in obese stressed patients.

Thirteen obese patients requiring parenteral nutrition for postoperative complications were studied prospectively to evaluate the efficacy of hypocaloric, high-protein parenteral feeding. Nonprotein caloric intake averaged 881 kcal/d or 51.5% of the patients' measured resting energy expenditure. Protein intake averaged 2.13 +/- 0.59 g/kg IBW. Serum albumin and TIBC increased significantly (2.8 +/- 0.5 g/dL to 3.2 +/- 0.4 g/dL, p less than 0.01, and 196 +/- 39 micrograms/dL to 248 +/- 49 micrograms/dL, p less than 0.05, respectively), and subjects lost weight (120.0 +/- 60.0 kg to 109.7 +/- 32.5 kg, p less than 0.05). Nitrogen balance studies in eight subjects suggested nitrogen equilibrium or positive balance can be achieved (+2.4 +/- 1.9 g/d). All patients exhibited complete tissue healing of wounds and abscess cavities and closure of fistulae. In obese, protein-depleted surgical patients net protein anabolism and clinical efficacy can be achieved with hypocaloric, high-protein feeding. Abundant endogenous fat stores provide obligatory energy.

Adult↗
PubMed1986

Central venous access with occlusive superior central venous thrombosis.

Thrombotic occlusion of the entire superior central venous system is a rare complication of central venous catheterization. Three patients are presented with complete occlusion of the superior vena cava secondary to prolonged central venous catheterization. Thrombotic occlusion of the superior vena cava precludes central venous access by conventional techniques. Thoracotomy with direct catheterization of the right atrium and inferior vena cava cannulation represent alternative approaches but may be associated with significant morbidity. The present report describes a unique combined angiographic/operative technique designed to obtain central venous access with low morbidity in patients with occlusive thrombosis of the superior central venous system.

Adult↗
PubMed1986

Total parenteral nutrition during pregnancy.

Several years ago, most obstetricians would have thought that any disease severe enough to require parenteral nutrition would also lead to infertility or early pregnancy loss. Women with many complex disease states have now been successfully treated by TPN during pregnancy, resulting in favorable outcomes for both mother and fetus. Theoretically, these patients, if not supplied with an adequate amount of essential nutrients by TPN, might have experienced excessive perinatal morbidity and mortality. The difficulties involved with studying maternal-fetal exchange processes in humans leave considerable gaps in our current knowledge about nutritional requirements during normal pregnancy. Some have suggested that subtle degrees of malnutrition may jeopardize normal growth and development. In states of severe protein calorie malnutrition, there remains little doubt that intrauterine growth is diminished. In such cases in which there is poor maternal weight gain, it may be critical to initiate some method of nutritional support. Whereas TPN during pregnancy has been sporadically employed in the treatment of cases of suspected fetal growth retardation, limited experience with this therapy suggests that at present we primarily direct treatment toward patients with specific disease states that are accompanied by overt malnutrition. Parenteral nutrition support should begin only after a period of adequate nutritional assessment and monitoring. If such support is necessary, TPN should be administered by a team of qualified knowledgeable individuals who are very familiar with the techniques. The relatively high rate of premature delivery associated with patients requiring TPN during pregnancy requires the presence of an intensive care nursery in the institution.

Female↗
PubMed1985

Macronutrient requirements in the malnourished cancer patient. How much of what and why?

Malnutrition is a prevalent problem in the hospitalized cancer population. Although the pathophysiology of cancer cachexia is incompletely understood, it assumes considerable clinical relevance because malnutrition is a potentially treatable problem associated with poor outcome. Once the clinician has made a decision to initiate enteral or parenteral nutritional support, the practical issue of macronutrient prescription necessitates review of existing animal and human data in order to formulate guidelines for nonprotein energy and nitrogen requirements for efficacious nutritional support in the malnourished cancer patient.

Amino Acids↗
PubMed1985

A quantitative evaluation of stress associated with indwelling superior vena cava cannulae in rats.

"Nonrestraining" superior vena cava (SVC) cannulae are commonly used in rat metabolic studies. The objective of this study was to evaluate the level of stress and metabolic alterations associated with surgical placement and subsequent maintenance and use of an indwelling intravenous cannula as measured by resting energy expenditure (REE), respiratory quotient (RQ), urinary nitrogen excretion, and substrate utilization pattern. Nine rats underwent SVC cannulation and six rats underwent sham operation. Postoperatively, animals were starved for 48 hr and then refed either parenterally or orally for 48 hr. Sham-operated animals adapted appropriately to starvation within 24 hr by decreasing REE 14% and increasing utilization of fat (RQ:0.89----0.78). Hypometabolic adaptation to starvation was delayed in cannulated animals until the second postoperative day, but appropriate alterations in energy substrate utilization were not affected by the presence of cannulae. Cannulae did not affect the metabolic response to oral refeeding with similar increases in REE and similar patterns of substrate utilization in sham-operated and cannulated animals. Animals refed parenterally demonstrated higher REE and apparent fat deposition (RQ greater than 1) consistent with continuous hypercaloric glucose administration. Urinary nitrogen excretion was not affected by the presence of cannulae. Cannula-associated metabolic alterations are minimal and transient and do not preclude detection and quantification of alterations associated with composition or utilization of exogenous substrates.

Animals↗
PubMed1985

Enhanced tumor response to cycle-specific chemotherapy by pulse total parenteral nutrition.

Exogenous nutrient administration has been shown to significantly stimulate tumor growth in numerous animal models. The present study was performed to determine if substrate-induced alterations in tumor metabolism could be exploited to potentiate tumor response to cycle-specific chemotherapy. Following subcutaneous mammary tumor (AC-33) implantation, 55 female Lewis/Wistar rats were randomly assigned to one of three nutritional regimens for 48 hr: (1) protein-depleted chow (0.03% protein) ad lib per os, (2) standard rat chow (22.0% protein) ad lib per os, or (3) total parenteral nutrition (TPN; 18.6% dextrose/2.8% amino acids). One-half of the animals in each group received a single dose of methotrexate (5 mg/kg im) while the remaining animals received placebo (saline) injections. At sacrifice, methotrexate-treated animals receiving TPN demonstrated a significantly smaller tumor volume (0.47 +/- 0.44 cm3) compared to animals given either protein depleted chow (1.30 +/- 0.76 cm3) or standard rat chow (1.34 +/- 0.83 cm3) (P less than 0.01). In this animal model, adjuvant TPN was found to significantly potentiate tumor response to cycle-specific chemotherapy with no detectable exacerbation of host toxicity.

Adenocarcinoma↗
PubMed1985

Interval nitrogen excretion and maintenance nitrogen requirements for parenteral nutrition in primates.

This paper discusses a regression technique for determining maintenance nitrogen requirements in well-nourished primates (M fascicularis) on total parenteral nutrition. Animals were administered a continuous glucose infusion, and parenteral nitrogen intake was varied at constant time intervals in a random order (from 0 to 1 g nitrogen/kg/day). Interval nitrogen balance (intake minus urinary nitrogen output) was plotted against interval nitrogen intake. The x-intercept was defined as the maintenance nitrogen requirement. First, 24-h intervals were used at a nonprotein caloric intake of 85 kcal/kg/day (approximately 175% of primate resting energy expenditure) and the nutritional adequacy of the estimated requirement evaluated prospectively. Next, 8-h balance intervals were used and the maintenance nitrogen requirements predicted by this abbreviated technique were compared to those obtained using the longer method. Finally, the short-interval technique was repeated at two other levels of continuous glucose infusion (60 kcal/kg/day and 8 kcal/kg/day) and the effect on predicted nitrogen requirement examined. Maintenance parenteral nitrogen requirements for primates may be determined in 48 h using the abbreviated techniques.

Animals↗
PubMed1985

Energy expenditure in acute trauma to the head with and without barbiturate therapy.

The increased energy expenditure associated with severe trauma to the head appears genuine but exhibits wide variation in its magnitude. Patients with severe acute trauma to the head without barbiturate treatment are hypermetabolic with an average energy expenditure 26 per cent over predicted. Barbiturate therapy abolishes this hypermetabolism and decreases energy expenditure to 14 per cent below predicted. In the individual patient, there appears to be a close relationship between the degree of suppression of energy expenditure and the serum barbiturate level. However, this relationship would appear to be different in each patient, and therefore, for this group, a significant correlation between energy expenditure and serum barbiturate level does not exist. The wide variability of energy expenditure in individual patients makes the estimation of energy expenditure by population predictive formulas imprecise. This may lead to incorrect estimates of caloric requirements and inappropriate provision of exogenous energy substrates. Although for those patients receiving energy expenditure and serum barbiturate levels in the individual may further aid in estimating the caloric expenditure for each individual, in order to provide appropriate amounts of calories to the patient with trauma to the head, energy expenditure should be measured in each instance.

Adolescent↗
PubMed1985

The effect of anorexia nervosa on bone morphometry in young women.

Changes in bone morphometry during chronic undernutrition were evaluated in 14 young women with anorexia nervosa (mean age +/- SEM = 25.5 +/- 4.4 yrs). Bone morphometry studies using the second metacarpal of the left hand showed significant depression for percent cortical area (p less than 0.05); cortical area (p less than 0.001) and combined cortical thickness (p less than 0.01) as compared to age, sex and race matched controls. A trend (p less than 0.10) was observed in study subjects for reductions in bone width and total area. Using percent cortical area (PCA) as the standard, subjects had mean cortical bone morphometry equivalent to 60-year-old women. Appendicular bone mass is significantly decreased in adults with anorexia nervosa. Anorexia nervosa should be considered in the differential diagnosis of osteopenia in young women, and serves as a model for studying the effects of chronic calorie and mineral malnutrition on bone remodeling at the time of attainment of peak bone mass.

Adult↗