Complementary Phenotyping of Maize Root System Architecture by Root Pulling Force and X-Ray Imaging.

The root system is critical for the survival of nearly all land plants and a key target for improving abiotic stress tolerance, nutrient accumulation, and yield in crop species. Although many methods of root phenotyping exist, within field studies, one of the most popular methods is the extraction and measurement of the upper portion of the root system, known as the root crown, followed by trait quantification based on manual measurements or 2D imaging. However, 2D techniques are inherently limited by the information available from single points of view. Here, we used X-ray computed tomography to generate highly accurate 3D models of maize root crowns and created computational pipelines capable of measuring 71 features from each sample. This approach improves estimates of the genetic contribution to root system architecture and is refined enough to detect various changes in global root system architecture over developmental time as well as more subtle changes in root distributions as a result of environmental differences. We demonstrate that root pulling force, a high-throughput method of root extraction that provides an estimate of root mass, is associated with multiple 3D traits from our pipeline. Our combined methodology can therefore be used to calibrate and interpret root pulling force measurements across a range of experimental contexts or scaled up as a stand-alone approach in large genetic studies of root system architecture.

Effect of nutritional status and 5-fluorouracil on protein synthesis in parenterally alimented LEW/Mai rats.

LEW/Mal rats bearing transplantable adenocarcinomas were maintained parenterally for 4 days on 1) a regimen adequate in amino acids and glucose and 2) severely hypocaloric glucose. Rats from both groups were given 17.5 mg 5-fluorouracil (FUra)/kg/day as a continuous infusion for 3 days. Cumulative nitrogen balance, fractional tissue protein synthesis rates, and liver and muscle distribution of FUra and its metabolites were determined. Results were compared to those found with a series of control rats that were not treated with FUra. No changes attributable to FUra were found in the starved rats (1.25 g glucose/day). In the fed rats (15 g glucose plus 2.5 g amino acids/day), FUra decreased the liver and diaphragm fractional protein synthesis rates and the nitrogen retention.

Alteration in pyruvate metabolism in the liver of tumor-bearing rats.

Weight loss associated with tumor burden has been postulated to be due to an energy imbalance resulting from increased hepatic gluconeogenesis secondary to Cori cycle activity. The mechanisms which control pyruvate metabolism are inherent to the control of gluconeogenesis in the liver. Therefore, the metabolism of pyruvate was evaluated in a transplanted tumor model in rodents which has previously shown an increased rate of hepatic gluconeogenesis. Female Lewis-Wistar rats received a s.c. injection of a suspension of mammary tumor cells in the left flank. Tumor-bearing rats were allowed ad libitum food consumption, and non-tumor-bearing controls were pair-fed to the consumption of their tumor-bearing cohorts. At Days 12, 13, and 14 following inoculation, tumor-bearing and non-tumor-bearing controls were used for in vivo body composition analysis or subjected to isolated liver perfusion. Animals were not fasted prior to sacrifice. Pyruvate use by the livers of tumor-bearing and pair-fed non-tumor-bearing rats was evaluated in the presence of 8 mM glucose and 5 mM lactate. Pyruvate clearance was increased by 270%, and pyruvate intake was increased by 212% compared to pair-fed non-tumor-bearing rats. Oxidation of pyruvate to CO2 was increased 130%, and pyruvate conversion to lactate was increased by 197% above that seen in pair-fed non-tumor-bearing rats. Gluconeogenesis from pyruvate was increased by 184% in tumor-bearing rats. The increased gluconeogenesis in tumor-bearing rats above that of control animals at a 5 mM lactate concentration suggests that some factor, other than substrate supply, may stimulate gluconeogenesis in tumor-bearing rats. Although the use of pyruvate was greater in tumor-bearing rats, the disposal of pyruvate carbon into CO2, lactate, and glucose was proportionally the same in both groups. Therefore, these data suggest that the increased metabolism of pyruvate in tumor-bearing rats is controlled by a mechanism affecting cellular pyruvate transport.

The treatment of anorexia nervosa with total parenteral nutrition.

Treatment outcome of 11 anorectic patients receiving total parenteral nutrition (TPN) is compared with outcome of anorectic patients receiving standard behaviorally oriented inpatient therapy. TPN resulted in significantly more rapid weight gain. Most patients could be successfully weaned from TPN to enteral feeding with continued weight gain. Complications during TPN were common including transaminase elevations and electrolyte imbalance. There was one death in the series. The role of TPN in the management of anorexia nervosa is discussed.

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.

The link between nutritional status and clinical outcome: can nutritional intervention modify it?

Most clinicians subjectively feel that malnutrition in surgical patients is associated with poor clinical outcome. This overview provides a chronologic review of studies relating poor nutritional status to increased surgical morbidity. Techniques for identifying surgical patients with clinically important nutritional deficits are discussed. Retrospective and/or non-randomized clinical studies evaluating the efficacy of perioperative forced feeding are reviewed. These data suggest a possible role for preoperative nutritional support of selected malnourished surgical candidates and provide the rationale for a large-scale nutrition-intervention clinical trial.

Immunocompetency in anorexia nervosa.

Twenty-two consecutively admitted patients diagnosed for anorexia nervosa were evaluated for cellular immune functioning by means of an anergy panel to test delayed hypersensitivity. The panel included candida, streptokinase-streptodornase, and mumps antigen administered by a standard protocol. A standard nutritional profile including current weight, usual weight, total protein, albumin, total iron-binding capacity, white blood cell count, total lymphocyte count, triceps skinfold, and arm muscle circumference was concurrently compiled on these subjects. Six of 22 patients studied were anergic. Visceral protein measures were generally within normal limits even in the most depleted patients. Malnutrition as measured by severity of weight loss and triceps skinfolds was significantly related to anergy, whereas visceral protein indicators (serum albumin, total iron binding capacity, transferrin) were not correlated with anergy. Anergy appeared to be related more strongly to anthropometric indices of malnutrition than to visceral protein values. Cellular immunity was generally preserved until weight loss was far advanced.

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.

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.

Effect of parenteral nutrition on protein synthesis in adult cancer patients.

The rate of whole body protein synthesis was measured with 15N glycine in three groups of subjects: 1) normal healthy adult controls, 2) semistarved adult patients with upper gastrointestinal tract malignancies and, 3) a group of patients similar to 2) except they were maintained parenterally on a regimen adequate in amino acids and glucose. By comparing the patient results with data obtained from rat studies with 15N glycine were concluded that the patients were protein rather than energy depleted.

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.

A randomized clinical trial of total parenteral nutrition in malnourished surgical patients: the rationale and impact of previous clinical trials and pilot study on protocol design.

The rationale for a large-scale clinical trial of preoperative total parenteral nutrition (TPN) is described in the context of previous clinical trials that have attempted to demonstrate reduction of operative morbidity with preoperative TPN. Defects in study design or execution potentially compromising the validity of these studies are analyzed. Results of a single-institution pilot study performed during the planning phase of the multiinstitutional preoperative TPN trial are presented. This literature review and pilot study provided the data necessary to permit appropriate design of many critical elements in the protocol for the clinical trial including sample size, eligibility criteria, duration and intensity of treatment regimens, and end-point criteria. The rationale underlying critical decisions in protocol design are presented in detail to allow more meaningful interpretation of the results of the clinical trial.

Weight gain and nutritional efficacy in anorexia nervosa.

To evaluate the usefulness of interval weight change in assessing nutritional support efficacy, we studied four anorexia nervosa patients (52% ideal body weight) requiring long-term total parenteral nutrition (TPN) for 63 +/- 18 days. Fluid and electrolyte deficits were corrected before the initiation of nutritional support. Resting energy expenditure was measured before the initiation of TPN and weekly thereafter, using indirect calorimetry. Daily caloric expenditure was estimated at 1.1 X resting energy expenditure, based on previous studies of continuous heart rate monitoring in this patient population. Daily excess calories were calculated as caloric intake minus caloric expenditure. Each patient was weighed daily and linear regression analysis (excess calories versus weight change) was performed for individual patients and the group over intervals of varying length. There was no individual or group correlation between excess calories and weight gain on a daily or weekly interval basis. Cumulative weight changes over the long-term course of TPN correlated significantly with cumulative excess calories for each patient and the whole group (r = +0.82, p less than 0.01). The excess calories required to gain a kilogram body weight ranged from 5569 to 15619 kcal/kg with a mean of 9768. Cumulative long-term weight changes during nutritional repletion in anorexia nervosa are meaningful indicators of caloric balance, but short interval weight changes (daily, weekly) are not. The caloric cost of weight gain is variable in this population.

Total body water and total body potassium in anorexia nervosa.

In the ill hospitalized patient with clinically relevant malnutrition, there is a measurable decrease in the ratio of the total body potassium to total body water (TBK/TBW) and a detectable increase in the ratio of total exchangeable sodium to total exchangeable potassium (Nae/Ke). To evaluate body composition analyses in anorexia nervosa patients with chronic uncomplicated semistarvation, TBK and TBW were measured by whole body K40 counting and deuterium oxide dilution in 10 females with stable anorexia nervosa and 10 age-matched female controls. The ratio of TBK/TBW was significantly (p less than 0.05) higher in anorexia nervosa patients than controls. The close inverse correlation found in published studies between TBK/TBW and Nae/Ke together with our results suggest that in anorexia nervosa, Nae/Ke may be low or normal. A decreased TBK/TBW is not a good indicator of malnutrition in the anorexia nervosa patient. The use of a decreased TBK/TBW ratio or an elevated Nae/Ke ratio as a definition of malnutrition may result in inappropriate nutritional management in the patient with severe nonstressed chronic semistarvation.

Controlled trial of the metabolic effects of a very-low-calorie diet: short- and long-term effects.

Resting energy expenditure (REE), weight, and body composition were measured up to seven times in 13 obese women during a 24-wk study. Patients were randomly assigned to a very-low-calorie diet (VLCD, 500 kcal/d) or a balanced-deficit diet (BDD, 1200 kcal/d). After 8 wk of supplemented fasting, REE of the VLCD patients decreased by 17% whereas that of the BDD patients was virtually unchanged. REE of the VLCD patients increased during 12 subsequent weeks of realimentation such that differences in REE between the two groups were not statistically significant at week 24 (VLCD = -11%, BDD = -2%). Reductions in weight and fat-free mass (FFM) were 12.1% and 3.6% for the VLCD patients and 10.6% and 4.1% for the BDD patients, respectively. There were no significant differences between the groups in pre- to posttreatment changes in REE normalized to FFM. Results suggest that REE recovers partially after consumption of a VLCD. They also provide evidence of a possible metabolic advantage of weight loss by a more moderate restriction.

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.

Laparoscopic-guided jejunostomy.

The proximal jejunum is the preferred site for long-term enteral access in the patient at risk for aspiration. Herein we describe a laparoscopic technique for the creation of a feeding tube jejunostomy. This minimally invasive approach is an alternative for patients requiring chronic postpyloric enteral feeding.

Energy metabolism during transplantation rejection.

The effect of transplantation rejection on energy metabolism is unknown. In order to investigate energy expenditure changes in this setting, we used an eight-cage rat indirect calorimeter to measure resting energy expenditure (REE) in the well-defined model of rat cardiac transplantation. Preoperative baseline measurements of REE were performed on Lewis recipients of allogeneic (Wistar Furth) or syngeneic (Lewis) heterotopic abdominal cardiac grafts (80.3 +/- 3.3 kcal0.75/day). Postoperatively, REE was measured on days 1 through 10, 15, and 20. An abnormal REE was defined as a greater than 10% change from the preoperative value. All cardiac allografts were rejected on postoperative day 7, whereas syngeneic hearts contracted for more than 100 days. Both groups of animals had a hypermetabolic response to surgery on postoperative day 1 compared with preoperative values (93.0 +/- 7.6 kcal/kg0.75/day, p less than 0.01). On postoperative day 2, REE normalized to preoperative baseline values in the syngeneic group and remained unchanged for the duration of the study (80.4 +/- 1.0, p = 0.49). In the allogeneic group, on postoperative days 3 through 6 an abnormal REE was recorded in 22 of 28 measurements compared with only 3 of 16 in the syngeneic group (p less than 0.001). After transplant rejection, REE normalized to preoperative values in the allogeneic group. Characteristic changes in energy expenditure occur during transplantation rejection. These changes in REE preceded rejection in this animal model.

Improved renal function and inhibition of renin and aldosterone secretion following peritoneovenous (LeVeen) shunt.

Twelve patients with cirrhosis, refractory ascites, and varying degrees of renal failure (creatinine clearance, 5 to 44 ml/min) were studied before and up to 2 weeks following peritoneovenous shunt. Creatinine clearance increased 60% or more in seven patients (group I) and 22% or less in five patients (group II). There were no significant differences in maximum urine output or sodium excretion between groups (group I, 4,272 ml/14 hr, 372 mEq/24 hr; group II, 3,722 ml/24 hr, 255 mEq/24 hr). Aldosterone and renin concentrations were higher in group I and showed a greater decrease after shunting. Renin substrate levels also were higher in group I and rose following shunt insertion, while group II remained low. Ascitic fluid was found to contain renin substrate in concentrations of approximately 25% to 50% of plasma concentrations. Patients with the greatest increase in creatinine clearance showed the largest rise in substrate concentration and fall in renin and aldosterone secretion, suggesting a dynamic relationship between these factors. That a diuresis could occur without significant change in these parameters in five of 12 patients suggests independent control mechanisms for renal salt and water excretion and glomerular filtration in the ascitic patient.

Direct right atrial catheterization for total parenteral nutrition.

A case report of a patient with severe nutritional deficiency and no adequate access to the central venous system for total parenteral nutrition is presented. Operative placement of a catheter directly into the right atrium allowed adequate nutritional support and led to a marked improvement in the clinical status of the patient and a gain of weight from 67 to 98 pounds. The technique of the procedure and its limited indications are discussed.