bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat loss from pitched roofs
Authors: Saluja G. S.
Published: September 2009

In the calculation of heat loss from a pitched roof it is usual to disregard gable areas, insulation location, loft space ventilation and air leakage from the dwelling, as advocated by the CIBSE. The CIBSE method does assume a general loss due to infiltration, but not specifically through the loft. In this paper the problem is analysed by considering steady-state energy transfer to and from the loft space as a function of various ventilation and air leakage (from dwelling) rates, gable heat transmittances, and the extent and location of insulation. The effects of loft ventilation and gable heat transmittance are negligible when the insulation is located entirely at the ceiling level. However, the CIBSE procedure underestimates the heat loss significantly when the insulation is partially or entirely at the roof level. Air leakage from the dwelling contributes significantly to the heat loss from the ceiling in all cases, but its effect on the building heat loss is included in the conventional method in the form of a general heat loss due to infiltration.
Thermal conductivity of vermiculite concrete: Effect of inclusion shape
Authors: Simpson A , Stuckes Audrey D
Published: September 2009

The thermal conductivity of three normal granular expanded vermiculite aggregate concretes, and six plate-like (approximately disc shaped) expanded vermiculite aggregate concretes, in the density range 500–1100 kg m−3, together with a sample of the cement paste matrix material of density 1428 kg m−3 has been measured. The plate-like vermiculite concrete was found to have conductivities some 20 to 30% less, for any given density, than the granular type. The large reduction in conductivity has been explained in terms of the shape of the inclusions, based on equations derived in an earlier paper.
Fin-type cold bridges: Heat loss and surface temperature
Authors: Cooper P
Published: September 2009

This paper describes theoretical modelling of fin-type cold bridges carried out as part of a programme of research into the effect of cold bridges on heat loss and condensation in buildings. One-dimensional fin theory is used to show that in many buildings, fins on the exterior of the envelope do not increase the local rate of heat loss and, therefore, do not lead to additional problems of cold bridging. The ratio of heat loss from a building envelope with fins to that from one without is found to decrease with increasing external heat transfer coefficient. A common cold bridge (a floor slab penetrating an external cavity wall) is analysed in detail by the finite element method. The effect of extending the floor slab to make an external fin (e.g. as a balcony) was found to have an insignificant effect on both heat loss and surface condensation risk. One-dimensional fin analysis is developed to produce a simple thermal model of externally extended cold bridges of utility in estimating minimum internal surface temperature.
Energy storage in a central heating system: Spa School field trial
Authors: Cohen R R , O'Callaghan P W , Probert S D , Gibson N M , Nevrala D J , Wright G F
Published: September 2009

Cranfield Institute of Technology and British Gas plc have undertaken a collaborative programme of tests of a system which interposes a heat store between a boiler and a distributive central heating network. This has culminated in a field trial at Spa School in London. It was predicted to lead to significant energy savings, to a lower installed boiler capacity requirement, and to reductions in installation costs for new and for some retro-fitted systems. Specifically, a thermally insulated 3235 1 hot water store was installed in the circuit between the existing modular boiler set and the hydronic ‘radiator’ network. The pipework was arranged so that the heating system could be operated either as configured originally or in the storage mode, in which case two of the five modular boilers were valved off. The two configurations were operated alternately (for four week periods), and their performances were carefully monitored over the 1985/86 heating season. The storage system performed successfully with a 40% lower installed boiler capacity. Boiler cycling was reduced by a factor of 15 and the mean boiler load factor rose from 37 to 70%. Analyses of results show that a 6% saving in annual fuel consumption was achieved by the storage system as compared with that of the highly efficient conventional system employing direct external compensation of the boilers. However, all this saving is attributable to the faster building preheat achieved with the store as, surprisingly, the annual efficiencies of the two systems were the same (in contradiction to the findings of other trials). The reasons for this are examined. Where direct compensation is not possible, the reduction in boiler cycling demonstrated will lead to a further substantial efficiency advantage of at least 10%.
Airflow measurement between three connected cells
Authors: Irwin C , Edwards R E
Published: September 2009

The multiple tracer gas technique developed at UMIST has been improved so that interconnecting airflows and cell air change rates can be calculated in up to three connected cells of a building. This paper describes the mathematical analysis required to calculate intercell airflows from site measurements of tracer gas concentrations varying with time. Several results of three-cell ventilation and air movement studies in a dwelling are given, thus illustrating the usefulness of the measurement and analysis technique described.
Obtaining and Maintaining Vascular Access in the Home Parenteral Nutrition Patient
Authors: Steiger Ezra
Published: September 2009

Obtaining and maintaining vascular access is a critical part of successful home parenteral nutrition (HPN) management. Most of the HPN related rehospitalization of patients is caused by problems associated with long‐term vascular access. The causes of death in HPN patients are mostly related to their primary underlying disease. However, approximately 12% of deaths in HPN patients are related to catheter‐associated problems. The appropriate placement of long‐term vascular access devices and their care and management should be familiar to all clinicians helping to manage these patients and will be discussed. (Journal of Parenteral and Enteral Nutrition26:S17‐S20, 2002)
Recognition, Prevention, and Treatment of Home Total Parenteral Nutrition Central Venous Access Comlications
Authors: Grant John
Published: September 2009

Placement of central venous catheters for long‐term administration of IV solutions in the home is associated with potential immediate and long‐term complications. These complications can seriously threaten a patient's well‐being and greatly increase costs. An understanding of anatomy and careful attention to detail can minimize the immediate complications, whereas thorough patient education and strict aseptic care techniques can reduce long‐term complications. Early recognition and treatment of complications when they do occur can reduce patient injury and costs. In this document, the incidence, recognition, prevention, and treatment of various immediate and long‐term complications will be discussed. (Journal of Parenteral and Enteral Nutrition26:S21—S28, 2002)
Parenteral Nutrition‐Associated Metabolic Bone Disease
Authors: Seidner Douglas L.
Published: September 2009

The incidence of parenteral nutrition‐associated metabolic bone disease is unknown. Initial reports from the early 1980s suggested that both osteoporosis and osteomalacia were quite common in patients who receive long‐term parenteral nutrition. The findings described in these early surveys provide a snapshot into the many factors that contribute to the development of metabolic bone disease. More recent evidence suggests that bone loss may not be as great with the initiation of parenteral nutrition as once was thought, and that most of the metabolic bone disease that is noted may be related to the patient's underlying illness. Although this recent information is reassuring, it is of the utmost importance to provide parenteral nutrition that minimizes further bone loss and promotes the formation of new bone. This review will describe the general features of metabolic bone disease and the abnormalities noted with parenteral nutrition‐associated metabolic bone disease, highlight the importance of preexisting illness and parenteral nutrition associated factors that contribute to the development of metabolic bone disease, and finally discuss an approach to avoid this debilitating complication of long‐term parenteral nutrition. (Journal of Parenteral and Enteral Nutrition26:S37—S42, 2002)
Physiology of the Aerodigestive System and Aberrations in That System Resulting in Aspiration
Authors: DeMeo Mark T. , Bruninga Keith
Published: September 2009

Background: Aspiration pneumonia remains a significant and often devastating problem in critically ill patients. It is unclear whether aspiration pneumonia occurs because of problems in the handling of oropharyngeal secretions or if the reflux of gastric contents is the major etiological factor. Additionally, the obvious breakdown of upper aerodigestive protective mechanisms in the critically ill patient population is largely unstudied. Finally, the impact and contribution of tubes, both endotracheal and nasoenteral, on aspiration pneumonia is unclear. Methods: A Medline literature search on scientific and review articles concerning the normal physiology of the aerodigestive tract and factors that compromised normal physiology was undertaken. Readings were supplemented by expert outside opinion from researchers in these fields and from the combined expertise from a multidisciplinary panel of experts assembled at a recent summit on aspiration pneumonia. Results: Changes in the normal physiology of the aerodigestive tract are vast and varied and dependent on the response to injury, iatrogenic interventions, and the use of nasoenteral and endotracheal tubes. The effects on gastric and esophageal motility are likely dynamic and represent an ongoing but changing risk of reflux for the patient. Nasoenteral and endotracheal tubes likely compromise upper aerodigestive protective mechanisms. Conclusions: More research is needed on the functioning of the aerodigestive protective mechanisms in critically ill patients. Understanding of the dynamic changes in gastrointestinal motility will also be an important factor to decrease the incidence of aspiration pneumonia in this patient population. (Journal of Parenteral and Enteral Nutrition26:S9‐S18, 2002)
Clinical Use of Gastric Residual Volumes as a Monitor for Patients on Enteral Tube Feeding
Authors: McClave Stephen A. , Snider Harvy L.
Published: September 2009

Background: The use of gastric residual volumes (GRVs) as a clinical monitor for patients receiving enteral tube feeding (ETF) is based on presumptions that are not physiologically sound and practice that is poorly standardized. Methods: This systematic review of the medical literature summarizes results from studies that evaluate the practice, interpretation, and impact on patient outcome from use of GRV. Results: Little data exist to support a correlation of GRV with gastric emptying, volume of gastric contents, or changes in the infusion of ETF. GRVs do not correlate to regurgitation or aspiration, and their use cannot be relied on to protect patients against aspiration pneumonia. Although recent reports suggest that elevated GRVs correlate to “intolerance” of ETF, use as a marker of impending clinical deterioration is limited by the fact that the timing of increases in GRV is unpredictable and high GRVs do not correlate independently to adverse outcome. The practice of GRV may in fact impede delivery of ETF by promoting inappropriate cessation and reducing potential infusion time. Conclusions: Modifying interpretation and the response by healthcare providers to GRV data are needed to preserve any clinical use for this practice. (Journal of Parenteral and Enteral Nutrition 26:S43‐S50, 2002)
When Is the Seriously III Patient Ready to Be Fed?
Authors: Spain David A.
Published: September 2009

Background: After assessing the critically ill patient for risk of aspiration, the clinician still must decide if the patient is ready to be fed. The goal is to identify critically ill patients who are likely to tolerate enteral nutrition and attempt to minimize complications. Methods: A synthesis of the both clinical and animal studies to identify factors related to patient readiness for enteral nutrition. Results: The key issue to be resolved is adequacy of resuscitation and restoration of mesenteric perfusion. Currently, there is no reliable clinical tool to measure gut perfusion. The best indicators currently are stabilization of vital signs, decreasing fluid and blood requirements, normalization of the base deficit, and lactate and removal of inotropic or vasopressor support. Conclusions: Most critically ill patients should be ready for enteral nutrition within 24 to 48 hours of intensive care unit admission. Critically ill patients who need catecholamine support, heavy sedation, or therapeutic neuromuscular blockade should probably not receive enteral nutrition until they have been stabilized. (Journal of Parenteral and Enteral Nutrition 26:S62‐S68, 2002)
Treatment of Aspiration in Intensive Care Unit Patients
Authors: Moore Frederick A.
Published: September 2009

Background: Aspiration is a common event, but the clinical consequences are variable. The primary determinants are the nature of the aspirated material and the host response to it. The purpose of this paper is to present treatment algorithms that should be employed in critically ill patients who experience aspiration. Methods: Expert review of the available literature was done to provide background information to support the logic of 3 treatment algorithms: (1) treatment of acute aspiration pneumonitis; (2) pulmonary care for acute aspiration; and (3) treatment of aspiration pneumonia. Results: The discussion of aspirations is separated into 2 clinical scenarios: (1) aspiration pneumonitis (sterile inflammation) versus (2) aspiration pneumonia (an infectious process). Aspiration pneumonitis should be treated by aggressive pulmonary care to enhance lung volume and clear secretions. Intubation should be used selectively. Early corticosteroids and prophylactic antibiotics are not indicated. Treatment of aspiration pneumonia requires diligent surveillance for the clinical signs of pneumonia. Treatment decisions are based on 3 factors: (1) clinical diagnostic certainly (definite versus probable), (2) time of onset [early (<5 days) versus late (≥5 days)], and (3) host factors (high risk versus low risk). There is no ideal antibiotic regimen. Unit‐specific resistance patterns and known frequency pathogens should direct broad spectrum empiric therapy. Invasive diagnostic techniques (such as bronchoalveolar lavage) should be used when the diagnosis is not certain. Antibiotic coverage should be narrowed once sputum culture results become available. Conclusions: Aspiration is common in critically ill patients and should be aggressively treated by these treatment algorithms. (Journal of Parenteral and Enteral Nutrition 26:S69‐S74,2002)
Nutritional Assessment with Body Composition Measurements
Authors: Shizgal Harry M.
Published: September 2009

The measurement of body composition by multiple isotope dilution provides an accurate and precise measure of both the nutritional state and the response to nutritional support. A multiple isotope dilution technique has been developed that permits measurement of the three major components of body composition: body fat, extracellular mass (ECM), and body cell mass (BCM). Normal body composition was defined by data obtained in 25 healthy volunteers. Malnutrition is characterized by a loss of BCM and an expansion of the ECM, and as a result the lean body mass is not significantly different from normal. The loss of body weight with malnutrition therefore often reflects the loss of body fat. The utility of body composition measurements was demonstrated by determining the effect of total parenteral nutrition on body composition to determine the relationship between caloric intake and the change in the BCM. A statistically significant relationship was developed which demonstrated that a caloric intake in the range of 30–40 cal/kg/day is required for maintenance. To restore a depleted or malnourished BCM requires a caloric intake in excess of that required for maintenance. The measurement of body composition by multiple isotope dilution is complex and time consuming, and requires specialized laboratory facilities and specially trained personnel. As a result, these measurements are not suited for routine patient management, but should rather be reserved for research purposes. (Journal of Parenteral and Enteral Nutrition 11:42S‐47S, 1987)
Measurement of Whole Body Cellular and Collagen Nitrogen, Potassium, and Other Elements by Neutron Activation and Whole Body Counting
Authors: James H.M. , Fabricius P.J. , Dykes P.W.
Published: September 2009

Whole body nitrogen can be measured by neutron activation analysis with an acceptable radiation dose; it is an index of body protein which, in normal subjects, is 65% cellular protein and 35% extracellular connective collagen. Whole body potassium can be measured by whole body counting without irradiating the subject; it is an index of body cell mass.

We measured whole body nitrogen, potassium, extracellular water, intracellular water, and fat‐folds. The differences between 37 malnourished patients and five normal subjects suggested that the patients had 9 kg less cell mass than normal, but no difference in extracellular mass. Measurements were made on eight patients before and after 14 days of total parenteral nutrition; balance of nitrogen intake and excretion also was measured. The changes were consistent with mean increases of 3 kg of cellular mass and 3 kg of fat with no change of extracellular mass.

The accuracy and sensitivity of the whole body measurements need further confirmation for use in patients with changing body composition. Where tissue wasting is largely from the cellular compartment, potassium could be a more sensitive index of wasting than nitrogen. Multielement analysis of nitrogen, potassium, chlorine, and carbon will probably be valuable in elucidating body composition in malnutrition. (Journal of Parenteral and Enteral Nutrition11:48S‐50S, 1987)
Application of Electromagnetic and Sound Waves in Nutritional Assessment
Authors: Heymsfield Steven B. , Rolandelli Rolando , Casper Katie , Settle R. Gregg , Koruda Mark
Published: September 2009

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. (Journal of Parenteral and Enteral Nutrition 11:64S‐69S,1987)
Immunological Function and Nutritional Assessment
Authors: Dominioni Lorenzo , Dionigi Renzo
Published: September 2009

Theoretically, a large number of tests of immunologic functions could be used for nutritional assessment. However, many of these immunologic tests require specialized laboratory skills and take a long time to perform. These tests provide little additional information to the clinician concerning the nutritional status of the patient, compared to the data that can be obtained from a few simple, selected immunologic measurements. Only a few immunologic tests are sufficiently simple, reproducible, and reliable indicators of nutritional status to be of practical value for routine nutritional assessment. These are the total lymphocyte count and skin tests. At present, all of the other immunologic measurements that have been reviewed should be considered as research tools for nutritional assessment. Immunological tests can be affected by many clinical variables unrelated to nutrition, such as specific pathologic conditions, immunodepressive therapies, accidental or surgical trauma, and infection, and this fact should be considered when using immunological tests to assess nutritional status. Malnutrition suppresses the acute‐phase response of plasma proteins. The measurement of the acute‐phase response of selected acute‐phase proteins can be a functional measurement of nutritional status. (Journal of Parenteral and Enteral Nutrition 11:70S‐72S, 1987)
Indirect Calorimetry in Malnutrition: Nutritional Assessment or Therapeutic Reference?
Authors: Kinney John M.
Published: September 2009

The measurement of gas exchange for use in indirect calorimetry is a clinical research tool struggling to find its proper place in the care of acutely ill and nutritionally depleted patients. Some investigators have proposed that it should be used as part of the nutritional assessment. Unfortunately, in common with many other measurements for nutritional assessment, the information provided must be integrated with other information. It is recognized that factors other than malnutrition may influence the level of the metabolic rate. Despite the lack of precision and specificity, the measurement of energy expenditure provides an important reference for determining patients' requirements for energy intake. As with many other procedures in clinical medicine, the more severely ill the patient, the less the accuracy of standard formulas for estimating energy expenditure. Thus, actual measurements of energy expenditure assume special value. (Journal of Parenteral and Enteral Nutrition11:90S‐94S, 1987)
Nutritional Assessment from the Perspective of a Clinician
Authors: Bozzetti Federico
Published: September 2009

The different uses of nutritional assessment are briefly reviewed. The parameters of nutritional assessment should be determined according to the use for which they are intended, such as nutritional epidemiology, preoperative assessment of nutritional risk, or nutritional monitoring during parenteral or enteral feeding. The roles of some nutritional variables that are used to identify and monitor high‐risk patients during nutritional repletion are examined. The main questions that confront the clinician are as follows: (1) are the nutritional indicators of surgical risk altered by poor intake of nutrients? (2) can these indicators be normalized with adequate feeding or are they abnormal as a result of the metabolic impact of the disease? (3) are these variables simple indicators of surgical risk or are they directly involved in the host‐defense mechanism? The importance is stressed of an integrated assessment of the patient's status when nutritional support is considered. This involves not only the static evaluation of the nutritional support according to standard parameters. but also a prospective and dynamic evaluation of nutrient requirements, length of hospital stay, and the curability of the basic disease. (Journal of Parenteral and Enteral Nutrition 11:115S‐121S, 1987)
Optimal Nutritional Indexes in Chronic Liver Disease
Authors: Merli M. , Romiti A. , Riggio O. , Capocaccia L.
Published: September 2009

A population of 70 patients with liver cirrhosis, most of whom were nonalcoholic, was studied. Distribution of ideal body weight and body mass index was below the median of controls, but very few patients were below the cut‐off points for normalcy. Distribution of triceps skinfold and arm muscle circumference was also below the median and, in most patients, was also below the cut‐off points. Serum visceral protein concentrations and anthropometric parameters each were reciprocally correlated with one another, but no correlation was observed between visceral proteins and anthropometric parameters. Serum visceral proteins appeared to correlate better with the degree of liver damage than with the degree of malnutrition. Therefore, anthropometric parameters seem preferable to serum visceral proteins for the assessment of nutritional status in patients with liver cirrhosis. (Journal of Parenteral and Enteral Nutrition11:130S‐134S, 1987)
Medium‐Chain Triglyceride‐Based Fat Emulsions: An Alternative Energy Supply in Stress and Sepsis
Authors: Bach André C. , Storck Daniel , Meraihi Zahia
Published: September 2009

Medium‐chain triglycerides (MCTS) and medium‐chain fatty acids (MCFAs) have special physicochemical properties such as small molecular weight, small interfacial tension against water, and for the fatty acids, solubility in biological fluids. As a result the metabolic pathways followed by these fats in an organism are different and simpler, or identical but more rapid, than those followed by long‐chain triglycerides (LCTS) and long‐chain fatty acids (LCFAs). Consequently the MCTs have found numerous applications in oral or enteral nutrition and, more recently, in parenteral nutrition. The infusion of conventional fat emulsions in stress and sepsis is still controversial. A main question is whether an MCT supply can be beneficial for these patients. In this review, we will discuss different aspects of modified lipid and protein metabolism: exchanges between exogenous fat particles and lipoproteins; exogenous fat clearance, storage, and oxidation; reticuloendothelial system function; nitrogen balance; and hepatic function. For each of these perturbations, the MCT/LCT and structured lipid emulsions are theoretically capable to provide an appropriate solution. The efficiency of these emulsions has been demonstrated experimentally on animal models of stress and sepsis. However, the value of MCT‐based fat emulsions for these pathological states has still to be ascertained by clinical studies. (Journal of Parenteral and Enteral Nutrition 12:82S‐88S, 1988)
Characteristics and Regulation of Hepatic Glutamine Transport
Authors: Bode Barrie , Tamarappoo Balaji K. , Mailliard Mark , Kilberg Michael S.
Published: September 2009

Glutamine is an important amino acid because of its key role in the transfer of both carbon and nitrogen between tissues in the body. Specific tissues are usually associated with either net synthesis or net utilization of glutamine, but the liver plays a central role in glutamine homeostasis, in that it can shift to function in either capacity. This capability, along with the localization of urea biosynthesis in the periportal hepatocytes, focuses attention on the transport mechanisms in hepatocytes for uptake and release of glutamine. Active transport of glutamine by hepatocytes is mediated by a Na+‐dependent activity termed system N, which exhibits a rather narrow substrate specificity mediating uptake of histidine and asparagine as well as of glutamine. This secondary active transport system allows for the net accumulation of glutamine against a concentration gradient and maintenance of intracellular concentrations of glutamine between 4 and 8 mM in the face of a plasma concentration of 0.6 mM. Utilization of the Na+ electrochemical gradient as a driving force ensures that the system N carrier catalyzes a unidirectional transport event favoring the cytoplasm. It is obvious from the glutamine gradient across the plasma membrane that efflux of this amino acid is typically slower than accumulation; measurement of saturable, Na +independent glutamine transport by system L substantiates this proposal. However, it is clear that under certain metabolic conditions the liver represents a source of glutamine for other tissues in the body and net efflux must occur. The system N transport activity in hepatocytes is regulated by hormones such as insulin, glucagon, and glucocorticoids, as demonstrated both in vivo and in vitro. The carrier activity is also responsive to substrate availability, as evidenced by induction of transport activity in vivo in response to high‐protein diets and in vitro by amino acid deprivation of cultured cells. In addition to these long‐term regulatory controls that require de novo protein synthesis, presumably of the carrier itself, system N activity is subject to a rapid modulation by substrate amino acids of systems A and N. This response occurs within minutes of exposure to these amino acids and is protein synthesis independent. It is likely that this complex set of regulatory signals affects system N transport activity in vivo and serves to maintain intracellular levels of glutamine within the hepatocyte, as well as allowing the hepatocyte to monitor and maintain plasma levels in support of whole‐body glutamine metabolism. The exact role of plasma membrane glutamine transport in whole‐body glutamine homeostasis will require extensive experimentation at the cellular and molecular levels. (Journal of Parenteral and Enteral Nutrition14:51S‐55S, 1990)
Effects of Glutamine‐Supplemented Diets on Immunology of the Gut
Authors: Alverdy John C.
Published: September 2009

Recent research developments have identified the gastrointestinal tract as the most metabolically active organ after surgical stress. In addition to fulfilling its role as an organ of digestion and absorption, the gut must maintain immunologic function in order to protect the host from invading pathogens. Central to the function of the intestinal immune system is the expression of secretory IgA, the most abundant immunoglobulin in external secretions. The synthesis and expression of IgA in secretions appear to be sensitive to dietary alteration and may be impaired after surgical stress. Data are presented suggesting that maintenance of gut mass and barrier function to bacteria via dietary manipulation may be essential to ensure host survival during critical illness. (Journal of Parenteral and Enteral Nutrition 14: 109S‐113S 1990)
Nutrition and Immunology
Authors: Van Buren Charles T.
Published: September 2009

“Clinical nutrition therapy stands poised upon the threshold of a new era — an era in which we shall approach the goal of providing our patients with diets which maintain normal immune defenses. ”1
Nutrition and Tumor Promotion: In Vivo Methods for Measurement of Cellular Proliferation and Protein Metabolism
Authors: Istfan Nawfal W. , Wan Jennifer M. , Bistrian Bruce R.
Published: September 2009

The notion that tumors act as “nitrogen traps” has led to the belief that nutrition support of the cancer‐bearing patient can enhance tumor growth. Proponents of this theory consider the provision of energy and essential nutrients as well as the influence of hormones and growth factors as responsible for this effect. On the other hand, nutrition administration in the debilitated cancer patient may improve antitumor host defense mechanisms and reduce tumor growth. This paper reviews methodologic issues related to the study of nutrition and cancer growth with emphasis on in vivo methods for measuring tumor protein turnover and cytokinetics. Using this combined approach, we previously demonstrated that dietary fat may significantly regulate tumor growth during chronic feeding as well as with short‐term intravenous nutrition support in experimental models. Although the mechanism of this effect remains unclear, we have reasoned that by altering arachidonic acid metabolism and prostaglandin synthesis, ω‐3 fatty acids could change tumor protein breakdown rates and inhibit the proliferation potential of these tumors. Acknowledging alternative hypotheses, we now present cytokinetic evidence that intracellular protein degradation may regulate tumor cell proliferation. Additional studies relating dietary fat, tumor protein metabolism and tumor proliferation potential are currently in progress. We propose that the effect of nutrition administration on tumor growth is complex and involves several regulatory systems. Thus, based on available evidence, an a priori tumor‐enhancing effect for nutrition support is clearly not warranted. Intracellular protein breakdown and host defense mechanisms, both of which are energy dependent, are important loci at which nutrition and tumor growth regulation could interact. Results from experimental tumor models have indicated that specific dietary fats, such as fish oil and structured lipids, may be used favorably in the nutrition support of the cancer patient. (Journal of Parenteral and Enteral Nutrition16:76S‐82S, 1992)
Perioperative Nutrition in Cancer Patients
Authors: Daly John M. , Redmond H.P. , Gallagher Hugh
Published: September 2009

Cancer patients have the highest incidence of protein‐calorie malnutrition seen in hospitalized patients, with significant malnutrition occurring in more than 30% of cancer patients undergoing major upper gastrointestinal procedures. Clinically significant malnutrition occurs as a result of diminished nutrient intake, increased nutrient losses, and tumor‐induced derangements in host metabolism. In the absence of adequate exogenous nutrients, the body utilizes endogenous substrates to satisfy the ongoing requirements of both host and tumor for energy and protein. In those patients with malignant obstruction of the gastrointestinal tract, the tumor itself may induce diminished nutrient intake. Present day treatment modalities including gastrointestinal resection, chemotherapy, and radiotherapy compound these metabolic derangements, further increasing the risk of postoperative morbidity and death. The presence of malnutrition in cancer patients has prognostic importance. In a review of more than 3000 cancer patients, DeWys and colleagues identified significantly improved survival in those patients without weight loss compared with those had lost 6% of their body weight (Am J Med 69:491–497, 1980). Other investigators have noted increased postoperative morbidity and mortality associated with malnutrition. Early hypotheses suggested that reversal of weight loss would improve survival. The development and refinements of enteral and parenteral nutrition have provided the opportunity for studying the relationship between nutritional supplementation and postoperative prognosis. Nutrition support is therefore often instituted to improve nutritional status and thereby reduce the risks of postoperative complications. This article addresses the beneficial role of preoperative nutrition therapy in cancer patients. (Journal of Parenteral and Enteral Nutrition16:100S‐105S, 1992)
Overcoming Difficulties in Demonstrating Health Outcome Benefits
Authors: Cella David F.
Published: September 2009

Nutrition interventions with cancer patients may produce benefits beyond those typically evaluated, such as increased appetite, food intake, and weight gain. Other benefits include enhanced mood, improved sense of well‐being, and increased socialization because of an increased ability to eat in public or with family. Along with the target benefits of nutrition interventions, these “untargeted” benefits have come to be clustered under the general rubric of health‐related quality of life. All medical treatments, including nutrition interventions, can be evaluated in terms of their total effect upon health‐related quality of life. However, demonstrating health outcome benefits of nutrition interventions can be very difficult. This difficulty is at two levels: conceptual and practical. Conceptual difficulties can be overcome by refining and clarifying the definition and measurement of health‐related quality of life. Practical difficulties are more diverse and must be tackled on a point‐by‐point basis, depending upon the unique characteristics of the disease being treated, the intervention being tested, and the context of the trial. This paper offers some guidelines and recommendations for overcoming many of the more commonly confronted barriers to successful demonstration of health outcome benefits from clinical nutrition trials with cancer patients. (Journal of Parenteral and Enteral Nutrition16:106S‐111S, 1992)
Optimal Design of Clinical Outcome Studies in Nutrition and Cancer: Future Directions
Authors: Maliakkal Roy J. , Blackburn George L. , Willcutts Harrison D. , Williams Michael , Levin Robert , Willcutts H. David , Elashoff Robert
Published: September 2009

Many studies have assessed the benefits of nutrition support in cancer patients. Except for studies directed at the treatment of severe malnutrition, most clinical trials have failed. Although prospective randomized controlled clinical trials (Phase III) remain the most reliable means of evaluating the efficacy of therapy, the available literature reports only results from small trials (Phase II to III), most of which appear to be contradictory and none of which conclusively answer the question being considered. To address this gap in knowledge, tools such as meta‐analysis have been adapted from the field of statistics. Meta‐analysis involves pooling results across several studies and provides a more precise estimate of treatment effect than can each individual study. However, clinical trials selected for meta‐analysis, although broadly similar, can differ significantly in terms of therapies used and clinical populations studied. Major cancer types with differing effects on food intake and malnutrition (eg, the mechanical obstruction in head and neck cancer vs the cytokine‐induced metastases associated with lung, ovarian, colon, and breast cancer) cannot be subject to the same analytic criteria. In this paper, the current state of clinical outcome trials in nutrition and cancer is examined, and the desired design for future studies is proposed. Research priorities include the conduct of Phase II clinical trials that use as outcome measures quality of life, performance status, and survival to identify optimal cancer‐specific and patient‐specific nutrition support. The next round of Phase III efficacy studies should establish the appropriate use of nutrition support in cancer therapy. (Journal of Parenteral and Enteral Nutrition16: 112S‐116S, 1992)
Necrotizing Enterocolitis: Pathophysiology and Prevention
Authors: Neu Josef , Weiss Michael D.
Published: September 2009

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in the neonatal intensive care unit. It is a disease of medical progress in that more very low‐birth‐weight neonates are surviving than ever before and are thus susceptible to this potentially devastating disease. NEC received very little attention in the literature before the 1970s but now is well known to all neonatologists and pediatric surgeons. The 1500 to 2000 infants that die every year from this disease in the United States and the large number of infants who develop short gut syndrome from this disease only represent the tip of the iceberg of the problems NEC causes. The widespread fear of NEC among neonatologists and pediatric surgeons has contributed in large part to the use of the IV route rather than the gastrointestinal tract for nourishing these infants for relatively long periods. The consequences of this include a high incidence of sepsis, high hospital costs, and potential long‐term neurodevelopmental disability because of poor nutrition during a very vulnerable period of growth and development. The purpose of this review is to provide a brief overview of the clinical presentation and current treatment for NEC, then provide a discussion of the pathophysiology on which strategies for prevention can be formulated. (Journal of Parenteral and Enteral Nutrition23:S13‐S17, 1999)
Glutamine Transport and Human Hepatocellular Transformation
Authors: Bode Barrie P. , Souba Wiley W.
Published: September 2009

Among other functions, the liver serves to regulate both glucose and nitrogen economy in the body, and in humans, the amino acid glutamine is a major gluconeogenic substrate and the primary extrahepatic ammonia shuttle. Accordingly, the liver acinus possesses a unique heterogeneous metabolic architecture suited to carry out these functions with glutamine‐consuming urea cycle and gluconeogenic enzymes in the periportal hepatocytes and a high capacity for glutamine synthesis in the perivenous hepatocytes, resulting in net glutamine balance across the hepatic bed under most conditions. Cytoplasmic levels of glutamine are significantly governed by the activity of the System N transporter in the plasma membrane of parenchymal cells; in this capacity, this glutamine carrier has been shown to represent a rate‐limiting step in metabolism via glutaminase. The unique properties of System N allow it to rapidly adapt in support of the dynamic demands of whole body ammonia and glucose homeostasis. In contrast to System N in normal hepatocytes, human hepatoma cells take up glutamine at rates several‐fold faster through a broad‐specificity higher affinity transporter with characteristics of System ASC or B0. It is currently hypothesized that the expression of this high activity carrier by hepatoma cells combined with accelerated metabolism and tumor‐induced derangements in hepatocellular architecture result in net glutamine consumption, and may underlie the diminished plasma glutamine levels observed in patients with hepatocellular carcinoma (HCC). The transport of glutamine through System ASC has been shown to regulate growth in some human hepatoma cells, which suggests this transporter may warrant consideration as a therapeutic target for HCC. (Journal of Parenteral and Enteral Nutrition23:S33‐S37, 1999)
Glutamine as an Immunoenhancing Nutrient
Authors: Saito Hideaki , Furukawa Satoshi , Matsuda Takeaki
Published: September 2009

New strategies for immunonutritional support include administration of special nutrients such as glutamine. Glutamine is important in several key metabolic processes of immune cells and enterocytes. Exogenous glutamine augments the functions of lymphocytes and macrophages. Neutrophils also reportedly utilize glutamine at a significant rate. Our recent studies demonstrated that glutamine enhances neutrophil function. This article focuses on the effects of glutamine on neutrophil function in surgical stress. Enteral glutamine administration enhanced peritoneal and hepatic bacterial clearance in our rat peritonitis model. Furthermore, IV glutamine supplementation improved the outcome of animals with severe surgical stress. Our in vitro study revealed that supplemental glutamine augmented the bacterial killing function of neutrophils from postoperative patients. Glutamine increased phagocytosis of the neutrophils. In addition, glutamine dose‐dependently increased production of reactive oxygen intermediates (ROI) by neutrophils. Thus, our studies suggest that glutamine supplementation may improve bactericidal function of neutrophils by increasing both phagocytosis and ROI production. In conclusion, glutamine plays an important role in neutrophil function. Glutamine may be useful for the prevention, and treatment, of severe infection in critical illness and trauma. (Journal of Parenteral and Enteral Nutrition23:S59‐S61, 1999)
The Impact of Alanyl‐Glutamine on Clinical Safety, Nitrogen Balance, Intestinal Permeability, and Clinical Outcome in Postoperative Patients: A Randomized, Double‐Blind, Controlled Study of 120 Patients
Authors: Zhu Ming Jiang  , Cao J.D. , Zhu X.G. , Zhao W.X. , Yu J.C. , Ma E.L. , Wang X.R. , Zhu M.W. , Shu H. , Liu Y.W.
Published: September 2009

Purpose: To evaluate the impact of alanyl‐glutamine (Ala‐Gln)‐supplemented parenteral nutrition (PN) on clinical safety, nitrogen balance, intestinal permeability, and clinical outcome in postoperative patients. Methods: One hundred twenty patients undergoing major abdominal surgery were enrolled. Protocol was approved and informed consent obtained. A double‐blind protocol was designed as used in Europe. The clinical safety and outcome were observed for 60 patients in 2 centers (30 each). Sixty patients from 2 additional centers (30 each) were observed for clinical safety, nitrogen balance, intestinal permeability, and clinical outcome. All patients received isonitrogenous (0.20 g/kg body wt per day) and isocaloric (30 kcal/kg body wt per day) parenteral nutrition. The study group received Ala‐Gln (Dipeptiven, Fresenius Kabi, Bad Homberg, Germany) 0.50 g/kg per day. Clinical chemistry variables, plasma amino acids profile, nitrogen balance, intestinal permeability (lactulose/mannitol ratio [L/M ratio]) were measured; hospital stay and infection rate were monitored. Statview was used for analysis of variance (ANOVA) or χ 2 tests. Data were expressed as means ± SD, and the significance level was p <.05. Results: The patients in both groups were comparable prior to the operation. Vital signs and clinical chemical parameters were similar between groups. L/M ratio was 0.047 ± 0.029 in control and 0.058 ± 0.049 in study group before the operation (AOD‐3). The L/M ratio was 0.132 ± 0.081 in the control group, and 0.097 ± 0.063 in study group on the seventh postoperative day. The difference of L/M ratio between groups was significant (p =.02). The cumulative nitrogen balance values were ‐5 ± 162 mg/kg for 6 days in control and 144 ± 145 mg/kg for 6 days in study group (p =.0004). All the patients recovered without incision infection. However, there were 3 cases that had infection‐related complications in the control group; the difference was not significant between groups. The hospital stay in the study group was 12.5 days, which was 4 days less than that of the control group (p =.02). Conclusions: Ala‐Gln‐supplemented PN was clinically safe, had better nitrogen balance, and maintained intestinal permeability in postoperative patients. The clinical outcome of the patients in study group was better; it was significantly different from the control group. (Journal of Parenteral and Enteral Nutrition 23:S62‐S66, 1999)
Insulin‐Like Growth Factor‐1 Modulation of Intestinal Epithelial Cell Restitution
Authors: Kai Chen  , Nezu Riichiro , Wasa Masafumi , Sando Kinya , Kamata Shinkichi , Takagi Yoji , Okada Akira
Published: September 2009

After superficial intestinal injury, the mucosal integrity is reestablished by rapid migration of epithelial cells from the adjacent area in a process called restitution. Our previous study suggested that growth hormone improves intestinal healing in an experimental small bowel ulceration, mediated by insulin‐like growth factor‐1 (IGF‐1). The aim of the present study was to assess the role of IGF‐1 in mucosal epithelial restitution using an in vitro epithelial wound model. Wounds were established in confluent monolayers of the intestinal cell line, IEC‐6. Migration was quantitated in the presence or absence of IGF‐1 as the number of cells migrating across the wound edge. Proliferation was assessed by thymidine incorporation. IGF‐1‐enhanced epithelial cell migration by 2‐ to 2.5‐fold after 12‐ and 24‐hour treatment, respectively, the first step involved in gastrointestinal wound healing. Cell proliferation was significantly stimulated by IGF‐1 as well. In addition, expression of transforming growth factor‐β (TGF‐β) mRNA was significantly enhanced in the wounded monolayers treated with IGF‐1. IGF‐1 receptor mRNA was found to be detectable throughtout the gastrointestinal mucosa and in the intestinal epithelial cells. In conclusion, these findings suggest that IGF‐1 plays an important role in reconstitution of intestinal epithelial integrity after mucosal injury. (Journal of Parenteral and Enteral Nutrition23: S89‐S92, 1999)