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Biomedical subjects

A C Campos

Publications and source records attributed to A C Campos.

At least 19 recordsLinked to original sources
PubMed1992

The comparative effects of abrupt vs. stepwise discontinuation of TPN in rats.

The comparative effects of discontinuing total parenteral nutrition (TPN: caloric ratio of glucose:fat:amino acid = 50:30:20) abruptly or in a stepwise manner on spontaneous food intake were investigated in two studies. Study 1: In 16 rats, TPN was given for 4 days, then stopped abruptly in eight rats. In the other eight rats, TPN was tapered; they received TPN at 75%, 50%, and 25% of their mean daily energy requirements per day for 3 consecutive days, and then switched to normal saline. Total parenteral nutrition induced a significant 60% reduction in spontaneous food intake (SFI) in both groups during the first TPN day. After 4 days of TPN, an 80% decrease in SFI had occurred in both groups. Resumption of SFI was significantly sooner in the abruptly-stopping group than in the stepwise-stopping group. But, in the latter group, there was a significantly greater cumulative caloric intake during the entire study. Study 2: In 32 rats, TPN providing either 100%, 50%, or 25% of their mean daily caloric requirements was given to three groups each of eight rats, for 3 days, then abruptly changed to normal saline; control rats received normal saline throughout. The TPN-induced decrease in SFI was proportional to the caloric density of the solution infused. Three days of 100%, 50%, or 25% TPN infusion led to an approximate 85%, 60%, or 35% decrease in SFI, respectively. Spontaneous food intake recovery was independent of the caloric density of TPN.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Dynamics of oral intake resumption after general anesthesia and operation in rats.

The influence of general anesthesia and operation on dynamics of postoperative food intake resumption was investigated in eight rats. A laparotomy was performed on each rat under anesthesia induced by intraperitoneally injected chloral hydrate. Spontaneous food intake and feeding indexes were continuously measured using an Automated Computerized Rat Eater Meter (ACREM) before and after operation. Although spontaneous food intake and all feeding indexes were depressed immediately following anesthesia and operation, each feeding index was depressed to a greater degree during the dark vs. the light cycle. Initially, rats fully capable of eating ate fewer, smaller, and shorter meals. The return to normal of each feeding index differed temporally. Thus, although meal number normalized by the third postoperative day, meal size by the sixth postoperative day, and meal duration by the fourth postoperative day, normalization of meal number during the light cycle occurred sooner than during the dark cycle, while the converse occurred with meal size and meal duration.

Anesthesia, General↗
PubMed1992

A critical appraisal of the usefulness of perioperative nutritional support.

Preoperative malnutrition is often associated with poor postoperative outcome, yet there is no consensus about whether perioperative nutritional support reduces postoperative complications to the level occurring in well-nourished patients undergoing similar procedures. This is partly because reports evaluating effect of perioperative nutritional support on postoperative outcome vary widely in number of patients studied, primary diagnosis, and duration and quality of perioperative nutritional support. These concerns warrant caution in interpreting reported results, even of randomized studies. However, analysis of published reports suggests that when total parenteral nutrition (TPN) is given to malnourished patients in adequate amounts for greater than or equal to 7-15 d preoperatively, significant improvements in both nutritional status and postoperative clinical outcome are likely to occur. Preoperative total enteral nutrition (TEN) is as effective as TPN in improving postoperative clinical outcome. Postoperative TPN, TEN, and ad libitum oral nutrition are equally effective in reducing postoperative complications. Potential candidates for surgery for whom prompt initiation of preoperative TPN or TEN may reduce operative morbidity and mortality irrespective of nutritional status can be identified on admission.

Enteral Nutrition↗
PubMed1992

Influence of parenteral feeding on spontaneous caloric intake and food selection in rats.

We compared spontaneous caloric intake (SCI) of rats exclusively receiving chow to SCI of rats given the choice of chow or Parmesan cheese, and then examined the influence of parenteral feeding on SCI and food selection. Six rats in a Chow Diet Group were offered Purina chow for 21 days, while five rats in a Choice Diet Group were offered Parmesan cheese or the same chow. Daily SCI (kcal/day) and body weight gain (BWG; g/day) were determined. Rats in the Choice Diet Group ate twice as much cheese as chow for the first 3 days of the experiment. Thereafter, SCI and BWG became comparable in both groups, with no significant differences for the rest of the study. In another group of nine rats, a central venous catheter was inserted. After 7 days, rats were offered chow and water ad libitum during the infusion of normal saline at 3 ml/hour for 3 days (Saline). Then, normal saline was replaced by a total parenteral nutrition (TPN) mixture of glucose, fat, and amino acid providing 85 kcal/day, and rats were randomized to eat either Chow Diet or Choice Diet. In both groups, SCI during TPN was significantly reduced as compared to the SCI on Saline. However, rats in the Choice Diet Group ate three times more chow than cheese during TPN. We conclude that a) food preference can increase SCI for short periods of time; b) TPN reduces SCI; c) TPN modifies food preference; and d) food preference does not increase SCI during TPN.

Animals↗
PubMed1991

Effects of continuous graded total parenteral nutrition on feeding indexes and metabolic concomitants in rats.

The influence of graded amounts of total parenteral nutrition (TPN) on food intake and feeding indexes was investigated in 90 rats housed in Automated Computerized Rat Eater Meter metabolic cages with free access to water and chow. When food intake was stable after catheter placement, 10 control rats continued with the 3 ml/h normal saline used for catheter patency, whereas study rats were given graded TPN continuously for 3 days, amounting to the equivalent of 26% (TPN-26), 53% (TPN-53), 81% (TPN-81), or 114% (TPN-114) of their daily caloric needs. TPN consisted of glucose, fat, and amino acids in the caloric ratio of 50:30:20. In study rats, the graded TPN depressed food intake, meal number, meal size, and eventually food consumption rate, meal sniffs, and intermeal sniffs in a dose- and time-dependent manner. During graded TPN, rats decreased total food intake by eating fewer, smaller, shorter meals at a decreasing consumption rate; sniffing activities were correspondingly curtailed. Stopping TPN led to normalization of feeding indexes. Blood glucose did not change while plasma insulin rose with graded TPN. A decrease in hepatic glycogen and an increase in hepatic triglycerides occurred. Plasma valine, phenylalanine, and methionine rose in a TPN dose-dependent manner. TPN-26 and TPN-53 significantly decreased whole brain amino acids; with TPN-114 no change occurred. Brain influx of tryptophan remained unchanged, but a progressive decrease in brain influx of tyrosine occurred. Whole brain dopamine and serotonin were depressed with TPN-26 and TPN-81 but were normal with TPN-114.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1990

Liver biochemical and histological changes with graded amounts of total parenteral nutrition.

We sought to determine whether an excess in energy intake as total parenteral nutrition would result in liver biochemical and histological changes in the presence of a functional gastrointestinal tract. Three groups of rats were given amounts of total parenteral nutrition that provided either 25% (total parenteral nutrition-25), 100% (total parenteral nutrition-100), or 200% (total parenteral nutrition-200) of a rat's energy requirements. Rat chow and water were available ad libitum. Food intake decreased in proportion to the amount of total parenteral nutrition infused; it ceased with total parenteral nutrition-200. Liver glycogen and triglyceride concentrations were higher with high energy intake (total parenteral nutrition-100 and total parenteral nutrition-200), while total liver nitrogen concentrations remained unchanged. No cholestasis, inflammation, or fibrosis was seen histologically. Fatty vacuoles were increased with total parenteral nutrition (more so with total parenteral nutrition-200) but a prompt return to normal liver features was observed after cessation of total parenteral nutrition and the resumption of normal food intake.

Animals↗
PubMed1990

Automated computerized rat eater meter: description and application.

A real-time Automated Computerized Rat Eater Meter was developed by modifying commercially available metabolic cages. Food access via a feeding tunnel was monitored by photocells. Food consumption was measured by an electronic scale. The signals thus generated were processed by a computer. This allowed us to continuously measure the spontaneous feeding behavior of free-feeding nondeprived Fischer rats for a sum total of 35 study days. Based on our data, we defined a meal as an episode of food consumption preceded and followed by at least 5 minutes of no feeding. Fischer rats showed periodic nychthemeral eating behavior. Food consumption, number of meals, meal sniffs, intermeal sniffs, and, consequently, eating activity were greater during the dark cycle than the light cycle. Meal duration, meal size, and thus food consumption rates remained constant throughout both cycles. Our modification of commercially available metabolic cages provides unique data for continuously monitoring rat feeding patterns over prolonged periods of time.

Animals↗
PubMed1990

Nutritional support in surgical practice: Part I.

Critical evaluation of the therapeutic benefit gained from provision of nutritional support requires knowledge regarding the nutritional status of those to whom it was given. The apparent effect of giving parenteral nutrition or enteral nutrition depends not only on how much and how well it is given, but also on how depleted the recipient is. Thus, nutritional assessment requires close examination before proceeding to assess the efficacy and potential benefits of the remedial measures of parenteral nutrition or enteral nutrition. Although preoperative malnutrition is associated with a poor operative outcome, there appears to be no consensus as to whether perioperative nutritional support can reduce postoperative complications to the level occurring in well-nourished patients undergoing similar procedures. This is partly because reports evaluating the effect of perioperative nutritional support on postoperative outcome vary widely as to numbers of patients studied, primary diagnoses, and the duration and quality of perioperative nutritional support. In Part I, these issues are explored in patients who are undergoing operations for cancer, trauma, or burns. Enteral nutrition appears to be as effective as parenteral nutrition in improving operative outcome, as compared with ad libitum oral nutrition. Postoperative enteral nutrition and parenteral nutrition are equally effective in reducing postoperative complications.

Enteral Nutrition↗
PubMed1990

Nutritional support in surgical practice: Part II.

On admission, a group of high-risk patients who are potential candidates for surgery can be identified, in whom prompt initiation of preoperative enteral or parenteral nutrition may reduce postoperative morbidity and mortality irrespective of the nutritional status. Among these are patients with inflammatory bowel disease, gastrointestinal fistulas, and pancreatitis. Substantial nutritional support has little or no direct effect upon the pathogenesis of the disease, but the discontinuance of oral intake may well have a beneficial effect on the basic disease process. Thus, the provision of enteral or parenteral nutrition gives the patient an optimal opportunity to marshal host defenses in support of healing. In organ system failures, e.g., acute renal failure, liver failure, and pulmonary failure, appropriate nutritional support may assist the patient in coping with the abnormal intermediary metabolism resulting from such failure until satisfactory organ system function returns. From this review, it seems reasonably clear that the initially malnourished patient is less able to successfully withstand the adverse effects of vigorous therapy and/or severe illness than is the well-nourished individual. Hence, correction of malnutrition, either before initiating therapy or concomitant with the treatment, is very likely to be beneficial.

Acute Disease↗
PubMed1989

Ability of a benign tumor to decrease spontaneous food intake and body weight in rats.

Malignant tumors induce anorexia and decrease spontaneous food intake and weight loss. Whether these effects are in part due to the tumor's physical size was investigated by inducing a benign cystic tumor mass with carrageenan in rats and then studying them for 21 days. Forty-two control rats were given subcutaneous injection of 3 ml of normal saline. Fifty-six study rats were given 3 ml of a 1.5% carrageenan solution subcutaneously, both in the right flank. Daily spontaneous food intake, body weight, and tumor weight were measured. Eight study and six control rats were randomly sacrificed on days 1, 3, 5, 7, 10, 14, and 21. Blood was obtained by cardiac puncture for albumin determination, and the tumor, carcass, liver, and spleen were removed and weighed. Tumor and tissue samples were histologically examined. All rats injected with carrageenan developed a benign cystic tumor mass. Early cystic wall consisted mainly of foamy macrophages with a light lymphoplasmacytic chronic inflammatory infiltrate and moderate vascularization. At day 21, cystic wall was more compact. The vasculature had collapsed and there were more pronounced fibroblastic response and collagen bundles. Average tumor weight by day 21 was 41 g. Average spontaneous food intake was depressed by about 15% from day 8 on in study rats as compared to controls. A significant decrease in carcass weight of 15.2% was observed in study as compared to control rats at day 21. Serum albumin was significantly decreased in study rats after day 5. Liver weight was significantly lower and spleen weight higher in study rats as compared to controls. These data suggest that some characteristics associated with cancer anorexia can be found in the absence of malignancy.

Animals↗
PubMed1989

Comparisons of body composition derived from anthropometric and bioelectrical impedance methods.

This study compared bioelectrical impedance analysis (BIA) measurements with current bedside techniques for determination of body composition in 18 normal volunteers to evaluate the relative usefulness of these methods as adjuncts to assessment in surgical nutrition. Anthropometrics (weight, height, and two skinfold thicknesses) and age and sex were used to derive body density (D) or total body water (TBW) by two methods. Method 1: D was calculated from the logarithm of skinfold thickness according to Durnin and Womersley, adapted for age and sex. Method 2: TBW was calculated from height, weight, and sex according to Hume and Weyers. Resistance and reactance were measured with a four terminal impedance plethysmograph; from these data plus height, weight, and sex, lean body mass (LBM) was derived. In each instance, Siri's and Pace and Rathburn's equations were used to derive the remaining parameters of body composition: D, total body fat (TBF), TBW, and LBM. Using the paired t-test, no statistically significant differences were seen in any parameter determined by the different methods. These results show that D, TBW, TBF, and LBM in a population of healthy individuals under steady-state conditions can be estimated by anthropometric-derived formulas with the same relative accuracy as that provided from estimates based upon BIA measurements.

Adult↗
PubMedDate not supplied

Home enteral nutrition via gastrostomy in advanced head and neck cancer patients.

We investigated whether home enteral feeding via a tube gastrostomy would enable patients with advanced malignant disease, who were unable to maintain themselves nutritionally via the oral route, to be independent of the hospital setting. Thirty-nine patients with advanced upper gastrointestinal and head and neck cancer had a tube gastrostomy placed. Before discharge, the patient was trained in the care and use of the gastrostomy feeding tube. Ten patients died of their disease before they could be discharged. During the 6-month period before gastrostomy insertion, the mean weight loss of the remaining 29 patients was 12.8%, and the mean body weight was less than 90% of ideal body weight. Prior to operation, the mean serum albumin and total lymphocyte count were 3.7 g/L and 1,087/mL, respectively. At discharge the mean caloric intake was 1.48 times resting energy expenditure. Home enteral nutrition was provided for a median of 94 days and resulted in stabilization of nutritional indices. During their median survival of 176 days, the 29 patients were admitted a total of 52 times. Twenty-eight percent of the patients were never re-admitted after gastrostomy and were adequately maintained at home, whereas 24% needed to be re-admitted once. Only 48% were re-admitted twice to assist in their nutritional management. Twenty patients received temporary home nursing services to aid in their transition. Four patients eventually resumed oral intake, and their feeding gastrostomies were removed.(ABSTRACT TRUNCATED AT 250 WORDS)

Energy Intake↗
PubMedDate not supplied

Electromyographic activity of the gastrointestinal tract following cholecystectomy.

Electromyographic activity of the stomach and small bowel, both in the fasting and fed states, was evaluated in the postoperative period of 8 patients subjected to cholecystectomy. The migrating motor complex (MMC) was recorded on the first postoperative day in 5 patients, on the second day in 2, and on the third day in 1. Vomiting occurred in 1 patient in whom the MMC was recorded only on the third postoperative day. Feeding caused substitution of the MMC by the fed pattern in the stomach and small bowel in all patients. It is concluded from this study that gastric and small bowel motility is normal on the first 2 days of the postoperative period in most patients subjected to cholecystectomy.

Adult↗
PubMedDate not supplied

Gastrointestinal motility of patients with Roux-en-Y reconstruction.

The electromyographic activity of the gastrointestinal tract was studied in 28 patients undergoing gastric, biliary, and pancreatic operations with reconstruction of the gastrointestinal tract with a Roux-en-Y limb. The Roux-en-Y limb was constructed 1 to 5 years before the study in 8 patients (chronic Roux-en-Y) and at the operation in which the electrodes were implanted in 20 patients (recent Roux-en-Y). All four phases of the migrating motor complex (MMC) were identified in the gastrointestinal tract, including in the Roux-en-Y limb. The duration of the MMC was 82.4 +/- 22.3 min in the patients with chronic Roux-en-Y and 89.0 +/- 25.1 min in the patients with recent Roux-en-Y. Food ingestion converted the MMC to the fed pattern in the entire gastrointestinal tract, including the Roux-en-Y limb in 16 (76.2%) of 21 recordings of the patients with chronic Roux-en-Y and in 27 (84.4%) of 32 recordings of the patients with recent Roux-en-Y. The duration of the fed pattern was 170 +/- 34 min in the patients with chronic Roux-en-Y and 154 +/- 26 min in the patients with recent Roux-en-Y. The findings of this study indicate that the electromyographic activity of the Roux-en-Y limb is normal during both fasting and fed states, even many years after the construction of the Roux-en-Y.

Anastomosis, Roux-en-Y↗
PubMedDate not supplied

Influence of subacute starvation on cardiac response to isoproterenol in rats.

Several studies have reported that the heart is severely affected by chronic malnutrition. However, the influence of these alterations on cardiac function remains unclear. The aim of this study was to evaluate the effects of subacute starvation on the heart chronotropic response to a beta-adrenergic agonist (isoproterenol). Twelve rats were fed rat chow ad libitum or a 50%-restricted diet for 17 days. The rats were killed, the right atrium was isolated and incubated, and in vitro spontaneous cardiac contractions and frequency were registered. Cumulative doses of isoproterenol were added to the solution until maximal cardiac frequency was achieved. A deficit of 25% in the weight gain was observed in study rats compared with controls (92.6 +/- 10.2 vs. 113.8 +/- 19.2 g, p less than 0.05). Mean daily food intake was 4.8 +/- 0.1 and 9.8 +/- 0.5 g/day for semistarved and control rats, respectively. The in vitro cardiac frequency of the semistarved rats was similar to that of controls (290 +/- 15 and 305 +/- 23 beats/min, respectively, NS). However, when isoproterenol was added to the solution, maximal cardiac frequency of the semistarved rats (435 +/- 51 beats/min) was lower than that of control rats (508 +/- 34 beats/min, p less than 0.005). These findings suggest that subacute starvation may alter the cardiac response to beta-adrenergic agonists.

Animals↗
PubMedDate not supplied

Acute acalculous cholecystitis.

Thirty-two patients with acute acalculous cholecystitis are presented. The age of the patients ranged from 1 to 80 years, with an average of 46.3 years. Acute acalculous cholecystitis occurred during the postoperative period in only four patients. Three patients were receiving total parenteral nutrition and 16 patients had one or more associated medical diseases. One patient had acute acalculous cholecystitis due to mechanical obstruction of the cystic duct caused by a diaphragmatic hernia. The most frequent signs and symptoms were right upper quadrant abdominal pain, nausea, vomiting, fever, abdominal mass, and jaundice. All patients were subjected to cholecystectomy. Nine (28.1%) gallbladder specimens had gangrene. Pericholecystic perforation was observed in four patients (12.5%) free perforation in one patient (3.1%), and empyema of the gallbladder in one patient (3.1%). Bacteria were cultured from 18 of 24 bile specimens. E. coli was the most common organism isolated. The overall postoperative mortality and complication rates were 15.6% and 40.6% respectively. The average hospital stay was 16.4 days.

Acute Disease↗