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Biomedical subjects

J L Mullen

Publications and source records attributed to J L Mullen.

At least 145 records · Page 8Linked to original sources

Central vein thrombophlebitis associated with a permanent silastic central catheter.

The use of silastic catheters for total parenteral nutrition has greatly expanded. Their decided advantages of flexibility and minimal thrombogenicity favor their use in the long-term nutritional support. This case report details the development of central vein thrombophlebitis associated with an indwelling central silastic catheter. This uncommon hazard of central venous catheterization is not eliminated by the use of silastic catheters.

Axillary Vein↗

Essential fatty acid deficiency in patients receiving simultaneous parenteral and oral nutrition.

Essential fatty acid deficiency is a common finding in patients nourished parenterally with hypertonic glucose and amino acids. In this study, we measured the linoleate concentration in the livers of 3 groups of patients. All the patients had operable upper gastrointestinal tract malignancies. Group I ate the hospital's regular diet ad libitum. Group II were given total parenteral nutrition (TPN), Group III received both enteral and parenteral nutrition and obtained about 35% of their caloric intake from food. The percentage of total liver fatty acids as linoleate were group I, 15.2 +/- 1.2%, group II, 3.7 +/- 1.4%, and group III, 2.8 +/- 1.6%. Data are expressed as the mean +/- 1 SEM. The patients who received 35% of their calories by mouth as food and the patients on TPN were found to be equally depleted in linoleate.

Aged↗

Hyperalimentation in primates. A nutritional model.

To establish the subhuman primate as an effective laboratory animal in parenteral nutrition research, 18 male macaque monkeys were adapted to chronic chair restraint and maintained on intravenous nutrition for 1- and 2-week periods. The animals remained in the restraint chairs for 11.6 +/- (2.3) weeks and the inferior vena cava catheters remained for 53 +/- (7.8) days. Catheter and metabolic complications during intravenous nutrition infusion were few and morbidity was low. The animals maintained weight, serum albumin, and serum transferrin levels as well as a positive nitrogen balance during the study period. The macaque is a highly suitable model for nutritional studies requiring a controlled environment during long-term studies.

Animals↗

A primate model for enteral nutrition by tube.

To establish an animal model for the controlled study of enteral nutrition by tube, five adult chair-adapted primates (Macaca fasicularis) had gastrostomy and jejunostomy tubes placed for the delivery of a modified protein isolate diet. Following 7 days of postoperative depletion with a hypocaloric infusion of dextrose (20 kcal, 0 g N/kg/day), the animals were repleted for 10 days with tube feedings (124 kcal, 0.73 g N/kg/day). There was no operative mortality or morbidity and each animal demonstrated conversion to anabolism by significant weight gain, positive nitrogen balance, and net protein synthesis as determined by [15N]glycine protein turnover rates. Significant correlation was found between caloric intake and nitrogen balance at the level of nitrogen provided in this diet (r = 0.88, p less than 0.05). This model was found to be well suited for the surgical and nutritional techniques required for the long-term study of enteral nutrition by tube.

Animals↗

Serum protein response to surgery and starvation.

To investigate the effect of stress on the dynamics of serum protein response during starvation, serum albumin, prealbumin, and transferrin changes were studied in six chair-adapted macaques during two separate 7-day test periods: (1) Starvation--NPO + IV D5/W (100 cc/kg/day), and (2) Surgery/starvation--laparotomy and gastrostomy + NPO + IV D5/W (100 cc/kg/day). During the starvation period, transferrin was the only protein that decreased from baseline values and did so at day 7 of the study period. In contrast, during the period of starvation following surgery, both prealbumin and transferrin were significantly decreased at both day 4 and day 7 of the study period, whereas albumin was only decreased at day 7 of this period. These findings indicate that the addition of a surgical stress to starvation results in a depression of serum protein levels that is not only of greater magnitude, but also more rapid in onset than observed with starvation alone. In addition, the differential response of prealbumin and transferrin to starvation and stress may provide a useful indicator of the presence and/or degree of stress in certain situations. The clinical utility of this finding remains to be ascertained.

Animals↗

Body weight measurement of patients receiving nutritional support.

A review of patient records over a 14-day period revealed that daily weights were recorded in only 65.5% of patients receiving parenteral nutrition and 53% of patients receiving enteral alimentation despite a hospital nursing practice requirement for daily weights during nutritional support. A semi-structured questionnaire was given to staff nurses to elicit their opinions regarding the importance of weight obtainment and to ascertain their reasons why patients are not weighted. Of 74 staff nurses who completed the survey, 68% considered weights "very important" but only 34% believed this attitude to be prevalent among their co-workers. The three reasons most often cited for failure to weigh patients were: (1) "patient too critically ill"; (2) "nurse felt other priorities of care existed; and, (3) "patient refuses." The two factors nurses most often felt should be changed to increase body weight measurement were "nurse staffing shortage" and "scales broken and/or unreliable." This study documents a need for both logistical changes (eg, equipment availability and reliability and timing of patient weights) and educational changes at both nursing staff and patient level to improve compliance with established requirements for daily weights during nutritional support.

Attitude of Health Personnel↗

Design considerations for multidisciplinary continuing nutrition education programs.

A multidisciplinary group of nutritional care providers was surveyed to assess degree of agreement on the relative importance of various areas of nutrition knowledge. A 35-item nutrition content area survey was mailed to a stratified, random sample (n = 400) of the American Society for Parenteral and Enteral Nutrition (ASPEN) membership representing dietitians, nurses, pharmacists, and physicians. Through the use of modified Delphi survey, respondents rated each content area as 'essential,' 'useful,' or 'nonessential' for inclusion in a proposed test to assess nutrition knowledge. Respondents from all disciplines agreed that they should be knowledgeable in 22 of the 35 content areas. Chi square tests were used to assess significant response differences among disciplines. Systematic differences were primarily between dietitians and pharmacists. The study results provide direction to multidisciplinary continuing nutrition education program planners regarding appropriate content for combined discipline programs as well as for those more discipline-specific.

Animals↗

Tumor effects on gluconeogenesis in the isolated perfused rat liver.

Alterations in metabolism in the tumor-bearing host can be explained by: 1) alterations of metabolic processes in the tumor itself, and/or 2) tumor effects on host metabolism. Tumor effects on host liver metabolism were studied using an isolated perfused rat liver preparation. The livers of fasted female Lewis Wistar rats with and without transplanted subcutaneous mammary tumors were perfused for 1 hr with medium containing 5 mM glucose and physiological levels of amino acids. The rate of gluconeogenesis, as measured by conversion of 14C-lactate to 14C-glucose, showed a significant increase in the rate of glucose production from lactate in tumor-bearing rats (2.40 vs 2.00 mumol/min/100 gm). Hepatic glycogen and 14C-glycogen content were not significantly different between the two groups. In order to evaluate whether this tumor model exhibits characteristic changes in metabolism previously reported in other animal tumor models, serum lactate, triglyceride, glucose, and blood urea nitrogen were measured in non-perfused animals. The serum concentration of lactate and triglycerides were significantly higher in tumor-bearing rats (0.9 mM vs 2.7 mM lactate; 244 mg % vs 365.5 mg % triglycerides). Serum glucose and blood urea nitrogen were not significantly different in the two groups. An effect of tumor on host energy metabolism and serum metabolite levels is demonstrated. A method for the study of host-tumor metabolic interactions is described.

Animals↗

Prehepatic total parenteral nutrition in the chair-adapted primate.

The relative efficacy of prehepatic and central venous infusion of total parenteral nutrition (TPN) was evaluated in a chair-adapted primate model. Four adult male monkeys (Macaca fascicularis) underwent surgical placement of a silastic catheter in both the portal vein (PV) and superior vena cava (SVC). Following recovery (10 days), each animal received two courses of TPN (100 kcal and 4 g of protein/kg/day) for 10 days each via the PV and SVC in an alternating crossover manner. The prehepatic (PV) infusion of TPN in the well nourished, chair-adapted primate results in maintenance of weight (PV: delta - 0.07 kg; SVC:delta - 0.07 kg), nitrogen equilibrium (PV:+ 0.8 g N/day; SVC: + 0.7 g N/day), and trends in serum albumin (PV:delta - 0.35 g %; SVC: delta - 0.38 g %), and total iron binding capacity (PV:delta + 44 mg %; SVC:delta + 8.67 mg %) comparable to the SVC route. No significant abnormalities in liver enzyme production were observed with either route of infusion. Whole body protein synthesis rates using 15N-glycine tracer were likewise comparable (PV = 2.05 g N/kg/day; SVC = 2.18 g N/kg/day). Prehepatic delivery and primary hepatic modulation of substrates does not substantially improve the efficacy of parenteral nutrient administration. Intestinal modification of substrates may be the most important contributing factor in the supposed superiority of enteral alimentation.

Animals↗

Estimation of fecal nitrogen in patients with liver disease.

The use of a fecal nitrogen (FN) predictive equation (Am J Clin Nutr 1978; 31:12-22, Cheng) based on dietary nitrogen intake (Nin) [FN (mg/kg/day) = 10.817 + 0.03 Nin(mg/kg/day)] was evaluated in patients with liver disease with and without concomitant lactulose therapy. Ten male cirrhotics were studied in 27 3-day nitrogen balance studies including measured daily total urinary nitrogen, total FN, and Nin calculated from weighted food records. The Cheng formula accurately predicted FN in cirrhotics not receiving lactulose who demonstrated normal digestion and absorption of dietary protein. However, the formula did not accurately reflect FN excretion in patients receiving lactulose who showed impaired protein digestibility and significantly increased fecal weight. The Cheng predictive equation is a useful index of FN excretion in patients with liver disease whose digestive and absorptive capacities are not compromised by exogenous factors.

Diet↗

Enhanced tumor response to cycle-specific chemotherapy by parenteral amino acid administration.

Forced feeding has been shown to effectively stimulate tumor metabolism in numerous animal models. Significant acceleration of tumor growth by exogenous nutrient administration is generally considered to be detrimental to the host. The present study was performed to determine if substrate-induced alterations in tumor metabolism could be exploited to enhance tumor response to cycle-specific chemotherapy. Following subcutaneous mammary tumor implantation (AC-33) and protein depletion, 39 female Lewis/Wistar rats were randomly assigned to one of four nutritional regimens for 48 hr: (1) protein-depleted food (0.03% protein) ad libitum po, (2) parenteral carbohydrate (18.6% dextrose), (3) parenteral amino acids (2.8% amino acids), or (4) total parenteral nutrition (18.6% dextrose/2.8% amino acids). Methotrexate (5 mg/kg im) was administered to all animals 2 hr after initiating these nutritional regimens. Tumor volume and host toxicity were monitored throughout the study. At sacrifice, significant reduction in tumor volume was observed in animals receiving parenteral amino acids (0.37 +/- 0.24 cm3) and total parenteral nutrition (0.25 +/- 0.18 cm3) compared to the group receiving protein-depleted food po (0.70 +/- 0.22 cm3) (p less than 0.01). In this animal model, the parenteral administration of amino acids with or without the addition of hypertonic dextrose was found to effectively potentiate tumor response to methotrexate without increasing host toxicity.

Adenocarcinoma↗

Relationships between serum total iron-binding capacity and transferrin.

The relationship between serum transferrin ( TFN ) and serum total iron-binding capacity (TIBC) in a clinical setting was evaluated in two related studies. The initial study evaluated 101 blood samples representing a cross-section of hospitalized adults. The samples were double assayed for TIBC using clinical and research methodologies. TFN was assayed by a commercial radial immunodiffusion method. Clinical laboratory TIBC correlated well with research laboratory TIBC (r = 0.87, slope = 0.97, p less than 0.001, n = 50) and the relationship of TIBC to TFN yielded the following equation: TFN = 0.83 TIBC -5.6 (r = 0.82, p less than 0.001, n = 101) where TFN = mg/100 ml and TIBC = micrograms/100 ml. The second study evaluated a new TIBC assay and its effect on the TIBC/ TFN relationship. Additionally, the TFN -TIBC relationship was evaluated at low normal and abnormal TIBC levels. In this second study, TFN = 1.0 TIBC -18.8 (r = 0.88, p less than 0.01, n = 126). Subsample analysis for specimens with TIBC between 105 and 160 showed a TIBC- TFN regression line that was not significantly different than the entire sample. Inclusion of ancillary patient data such as hemoglobin and hematocrit did not improve the relationship between TFN and TIBC in either study. The relationship was unaffected by age, sex, race, disease, treatment, fever, surgery, degree of nutritional support, blood transfusion, or blood chemistry parameters in either study. Laboratories deriving TFN from measured TIBC as a nutritional status indicator must determine the relationship for the specific procedures being used in their laboratories.

Age Factors↗

Indirect calorimetry in chair-adapted primates.

This paper describes the construction of an indirect calorimeter for measurement of respiratory gas exchange in the chaired primate. Preliminary determinations of energy expenditure and respiratory quotient in five animals under a variety of dietary conditions suggest that this system will prove useful in the laboratory study of primate nutrition, energy metabolism, and cardiorespiratory physiology. Other possible uses and limitations are discussed.

Adaptation, Physiological↗

Urea nitrogen excretion in chair-adapted primates.

To evaluate the temporal pattern of urea excretion in chair-adapted primates (Macaque fascicularis) on continuous total parenteral nutrition (TPN), two groups of five animals were studied. Group I received continuous TPN (75 glucose kcal; 0.56 g nitrogen; and 100 ml fluid per kg per day) while Group II received a single morning isonitrogenous oral meal along with a continuous isovolemic intravenous infusion of 0.45% saline. Urine was collected hourly in group I for 2 days and every 4 hr in group II for 5 days and analyzed for urea content. Time series analysis revealed no periodicity of urea excretion in either group. Six animals were then studied for a total of 46 TPN days to define the relationship between the urea content of a single 3-hr morning urine aliquot and its respective content in a 24-hr collection. A significant linear relationship was found (r = +0.76, p less than 0.01). However, using this relationship, a reasonable estimate (+20%) of measured 24-hr urea output was achieved only 50% of the time using a single 3-hr urea output. Chair-adapted primates maintained on continuous TPN or a single oral meal with continuous saline infusion do not exhibit a periodic pattern of urea excretion. The variability in 3-hr urinary urea output in the chaired primate on continuous TPN does not consistently permit accurate estimation of the coincident 24-hr urinary urea output.

Adaptation, Physiological↗

Treatment effects of parenteral vitamins in total parenteral nutrition patients.

To determine the prevalence of abnormal vitamin levels in an adult hospitalized population requiring total parenteral nutrition (TPN) and to assess the effect of routine parenteral vitamin therapy on vitamin levels, we studied 35 general surgical patients. Assays for 12 vitamins were performed both before and after a standard 10-day course of TPN. Patients were given nothing by mouth. The first 25 patients received a daily parenteral vitamin mixture tailored to the recommendations of the Nutrition Advisory Group of The American Medical Association (maintenance dose). The final 10 patients were given a parenteral multivitamin dose providing substantially greater amounts of most vitamins (repletion dose). Only 58% (190/324) of pre-TPN vitamin levels were normal, 25% were low, and 17% were high. No patient had fewer than two abnormal baseline levels. Vitamin levels did not correlate with serum albumin, body weight, or nitrogen balance. After 10 days of treatment, only 39% of low pre-TPN vitamin levels improved; most (45/62) of the low posttreatment levels were low at baseline. The higher repletion dose resulted in a significantly (p less than 0.01) greater percent increase in vitamin A, C, and pyridoxine levels. The prevalence of abnormal vitamin levels in this population is high (42%). Standard parenteral vitamin therapy leads to marginal improvement in abnormally low pre-TPN vitamin levels.

25-Hydroxyvitamin D 2↗

Spontaneous retraction of indwelling catheters: previously unreported complications.

The development of totally implantable reservoir central venous access systems has been an important advance in patients requiring long-term central venous access. With lower rates of infection and thrombosis than those with external catheters, they have potential for greater longevity and patient acceptance. Complications such as subcutaneous prosthetic infection, infusate extravasation, and difficulty in locating and puncturing the port have been reported. We present two cases of catheter migration and withdrawal from the subclavian vein. This presumably occurred from the action of the underlying pectoralis muscle on the reservoir, as well as a "jetting effect" during flushing. We make suggestions for prevention of similar problems in the future.

Adult↗