Intragastric Tube Research Articles

Metabolic and immune effects of dietary arginine supplementation after burn.

The effect of supplemental dietary arginine on metabolism and immunity was studied in 36 burned guinea pigs (30% of total body surface area) with previously placed catheter gastrostomies. The animals were randomized into four groups. After an initial three-day adaptation period, all groups received continuous isonitrogenous, isocaloric (175 kcal [735 kJ]/kg/d), and isovolemic intragastric tube feedings until postburn day (PBD) 14. Groups A, B, C, and D received 0%, 1%, 2%, and 4%, respectively, of total energy intake as arginine given in the form of crystalline arginine hydrochloride with 22%, 21%, 20%, and 18%, respectively, of total energy as whey protein. The average body weight after burn decreased equally in all groups. Resting metabolic expenditure on PBD 6 was higher in groups B (151% +/- 6% of preburn) and C (156% +/- 7%) than in groups A (131% +/- 4%) and D (136% +/- 3%). Ear-thickness response to dinitrofluorobenzene challenge on PBD 12 showed the best response in group C. The mortality rates of groups A, B, C, and D were 56%, 29%, 22%, and 56%, respectively. This study suggests that oral dietary arginine supplementation up to 2% of energy intake may be beneficial after burn injury.

Orally induced tolerance to casein in mice on normal mouse chow

We examined the ability of bovine casein to induce oral tolerance in BDF 1 mice raised on a normal mouse chow diet. Giving 20 mg casein 1 × or 4 × by intragastric tube or for 28 days at 1 mg/ml in drinking water failed to have a significant effect ( P > 0.2) on the subsequent immune response to parenteral casein, suggesting that casein was not an effective oral tolerogen. However, we discovered that most normal mouse chow contains casein. When BDF 1 mice were raised on a casein-free diet, and treated as above, they showed marked suppression of subsequent responses to parenteral casein ( P < 0.01). Our results indicated that mice on the normal diet were presuppressed by the dietary exposure. Examination of several other normal mouse chows revealed that they all contained casein as a protein source. A possible effect of prior exposure must be considered in all experimental animal studies involving immune responses to antigens which may be present in the environment.

Effect of oltipraz on hepatic glutathione content and metabolism, DNA damage and lipid peroxidation in mice as a function of age

Female mice between the ages of 1–18 months were treated with 50 mg oltipraz/kg by intragastric tube every other day for 5 doses. At all ages, oltipraz resulted in significant increases in hepatic glutathione content and glutathione reductase and glutathione S-transferase activities. Oltipraz also produced decreases in hepatic DNA damage (single strand breaks) and lipid peroxidation (malondialdehyde content). Highest hepatic glutathione content and glutathione reductase and glutathione S-transferase activities occurred in mice approximately 9 months of age, and declined thereafter. Oltipraz administration to 18 month old mice increased glutathione content and glutathione S-transferase activity approximately to the levels observed in 9 month old mice. Oltipraz may be effective in retarding the free radical reaction processes associated with aging and cancer.

Ethanol intoxication stimulates lipolysis in isolated Golgi complex secretory vesicle fraction from rat liver.

Ethanol (0.6 g/100 g) was administered orally to rats by means of an intragastric tube. This caused an accumulation of secretory vesicles laden with VLDL particles which were seen 90 min after administration and later disappeared. Lysosomes and Golgi complex secretory vesicle (GCSV) fractions were isolated. The proteolytic and lipolytic activities of these fractions were measured in order to assess their possible role in the elimination of the initially retained secretory material. There was no change in proteolysis neither in lysosomes or in the GCSV-fraction from ethanol-intoxicated rats when measured by the release of degradation products during incubation. Similarly, the activities of acid hydrolases were unaffected by acute ethanol intoxication. On the other hand, lipolysis increased by some 50-100% in the GCSV fraction, whereas the lysosomes displayed unchanged lipolytic levels compared with controls. Ultrastructurally, the GCSV-fraction from ethanol-intoxicated rat livers showed signs of disintegrated VLDL particles. It is concluded that acute ethanol intoxication causes an increase in lipolysis but not in proteolysis in the operationally defined GCSV fraction. Since triacylglycerol lipase activities did not change in the GCSV fraction, increased amounts of substrate seem to cause the enhanced lipolysis observed.

Lead silicate toxicity: A comparison among different compounds

The aim of this report is to point out the relative toxicity of different commercial products containing lead silicates by studying their in vitro solubility and rate of absorption via the respiratory and digestive systems, compared with those of red lead (lead tetroxide). In vitro solubility was tested, by a modified Brimsdown method, with bidistilled water, saline, blood serum, pleural fluid, and dilute hydrochloric and acetic acids as solvents. Experimental animals were administered 25 mg equivalent mean doses using an intragastric tube or endotracheal intubation. Results showed that in vitro solubility gradually increases from distilled water, through saline and biological fluids, to acidic media. Lead absorption via the respiratory system is rapid and persistent, with small differences among the tested compounds. Less information can be gained from intragastric experiments. No correlation was found between in vitro solubility and in vivo absorption. On the other hand, in vitro studies must be strictly standardized. The relative absorption of the different materials, compared with red lead showed that all of them have to be regarded as equally toxic.

Effects on mouse embryos of in utero exposure to saccharin: teratogenic and chromosome effects.

For teratogenesis studies, pregnant ICR albino mice were administered saccharin by three routes and at three different doses by each route as follows: Intraperitoneal injection of 500, 1,000, or 2,000 mg/kg saccharin on day 10 of gestation; intragastric tube delivery of 5, 10, or 25 mg/kg/day of saccharin on days 5-15 of gestation; and as drinking water containing a 5, 10, or 20% solution of saccharin from day 0 through day 17. Appropriate controls were used for each set. No increase in either resorptions or malformations was found in mouse embryos whose dams had received saccharin by any of the three routes. For chromosome studies, saccharin was administered IP to pregnant ICR albino mice on day 10 of gestation as either a 1,000 mg/kg or 2,000 mg/kg dose. To demonstrate sister chromatid exchanges (SCE), bromodeoxyuridine was administered as 16 consecutive half-hourly doses of 25 mg/kg during the 8 h prior to saccharin injection. In addition, one group received two doses of BrdU and 2,000 mg/kg saccharin 8 h apart to demonstrate SCE frequency following exposure to saccharin for two cell cycles. The mice were given colchicine (4 mg/kg) 6 h after the final injection and killed 2 h later. Embryonic cell suspensions and metaphase spreads were prepared by routine methods. Metaphase spreads were examined for breaks or gaps (after Giemsa staining), for G-banding (using the ASG technique), for C-banding (using Giemsa staining after exposure to 0.07 N NaOH and incubation in 2 X SSC at 60 degrees C), and for SCE by the Hoechst-Giemsa method. Fifty metaphase spreads were counted for each experimental condition.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on intestinal trematodes in Korea: XVIII. Effects of praziquantel in the treatment of Fibricola seoulensis infection in albino rats.

The therapeutic effect of praziquantel on Fibricola seoulensis infection were studied by experimental infection of albino rats with the metacercariae obtained from the snakes. Total 51 albino rats were infected each with 500 or 1,000 metacercariae in number through intragastric tubes. One or four weeks later the rats were treated with 1, 5, 10 or 20 mg/kg sigle dose of praziquantel and sacrificed after 3 days or 10-120 minutes to search for the worms in their small intestine. The worms recovery rate at 3 days after the treatment was 10.7% in 1 mg/kg does group and 0.03~0.2% in 5, 10 and 20 mg/kg group, while that of untreated control was 51.3%. The minimum effective dose to treat F. seoulensis infection in the rats is considered to be 5 mg/kg in sigle dose. By observing the distribution pattern of worms in the small intestine after the treatment, dislodgment of the worms froms the duodenum, thier normal habitat, to the lower portion was recognizable within as early as 10 minutes. The majority of worms was found to have descended to the ileo-caecal portion after 60-120 minutes.

Optimal lipid content for enteral diets following thermal injury.

This study was performed to determine the effects of different amounts of lipid in enteral diets during the postburn period. Forty-five guinea pigs with catheter gastrostomy received a 30% total body surface area full thickness flame burn. After burn they were given intragastric tube feedings using five diets at different dietary lipid composition: 0, 5, 15, 30, and 50% of nonprotein calories. Total calories administered (175 kcal/kg/day), protein content and composition (20% of total calories), total volume, and vitamin and mineral content were constant in all animals. At postburn day 14, body weight, carcass weight, and muscle weight were the greatest in 0 and 5% lipid groups, and the least in 30 and 50% lipid groups. Serum transferrin was highest in the 5 and 15% lipid groups, and lowest in the 30 and 50% lipid groups. Total nitrogen content in muscle and cumulative nitrogen balance were best in the 15% lipid group. Liver fatty infiltration, caused from a larger proportion of carbohydrate administration, was greater in the 0 and 5% lipid groups and less in 15 and 30% groups. It is concluded that dietary lipid levels between 5 and 15% of nonprotein calories are optimal for nutritional support after burn injury. The nutritional management of postburn patients with higher levels of dietary lipid should be reconsidered.

Study of Electromechanical Activity of the Stomach in Humans and in Dogs With Particular Attention to Tachygastria

The relationship between electric and mechanical activities of the gastric antrum was investigated in both humans and dogs. In 2 patients, in whom platinum monopolar electrodes were implanted on the serosal surface of the antrum and a perfused manometric tube was placed in the stomach, the number of gastric contractions detected by manometry was only less than 50% of the pacesetter potentials accompanied by action potentials or second potentials. No contraction of the stomach was recorded by manometry when pacesetter potentials occurred without action potentials or second potentials. The relationship was further investigated in 11 anesthetized dogs prepared with implanted electrodes and sensitive ministrain gauges implanted on the serosal surface of the stomach and an intragastric manometric tube. In these dogs, phasic contractions were always recorded by the method using ministrain gauges although the electrical activity showed only PSPs without action potentials or second potentials. The manometry, however, could not recognize these phasic contractions. When the stomach was stimulated by bethanechol infusion through the splenic artery, as in the human stomach, the manometry detected less than 50% of gastric contractions detected by the strain gauge recording. The gastric dysrhythmia including tachygastria, tachyarrhythmia, and bradygastria was induced in 10 dogs by epinephrine, 100 micrograms X kg-1 X h-1, infused via the splenic artery. During the period of gastric dysrhythmia, the phasic contractions disappeared and no contraction associated with action potential could be observed. The phasic contractions reappeared as long as the PSPs occurred regularly in a frequency of 4-5 cycles/min during either the control period or during the period of epinephrine infusion. The epinephrine-induced gastric dysrhythmia was blocked or reversed to normal pacesetter potentials by intraarterial infusion of phentolamine. Our study suggests the following: (1) the pacesetter potentials not only pace and direct gastric contraction, but they may also play a role in the genesis of phasic contractions of the stomach, and (2) gastric contractions detected by sensitive strain gauges are not always recorded by the intraluminal manometry and, thus, gastric dysrhythmia may not be detected by the manometry in humans.

The effects of nutrition on unconjugated plasma bilirubin concentrations in squirrel monkeys.

Bolivian squirrel monkeys (Saimiri sciureus) have fasting unconjugated hyperbilirubinemia (males: 2.0 +/- 0.14; females: 3.0 +/- 0.26 mg per dl) which resembles that of humans with Gilbert's syndrome. Closely related Brazilian squirrel monkeys have fasting levels (males: 0.29 +/- 0.045; females: 0.36 +/- 0.073 mg per dl) similar to normal people. The purpose of this study was to identify the underlying mechanisms and the nutritional factors involved. Both Bolivian and Brazilian squirrel monkeys had higher plasma bilirubin concentrations after an 18 hr fast than 4 hr after feeding. The development of fasting hyperbilirubinemia was progressive for at least 24 hr. Both populations that received a semipurified diet containing 5% fat had lower fasting and postprandial plasma bilirubin concentrations than did animals receiving 0.3% fat but much lower than those receiving 20% fat. The emulsified complete meal, or glucose, sucrose, casein, or lactalbumin alone when given by intragastric tube lowered the plasma bilirubin levels of Bolivian monkeys to less than one-half of fasting values within 1 to 4 hr. Water or butter did not have a significant effect. Glucose or fructose, when given intravenously, lowered the plasma bilirubin levels to less than half of fasting values; the fat emulsion, Intralipid, did not have a statistically significant effect. Subcutaneous epinephrine increased plasma glucose concentrations and reduced plasma bilirubin concentrations. When glucose or glucose plus butter were given by stomach tube to Bolivian squirrel monkeys for 48 hr, a very low plasma bilirubin concentration resulted whereas butter given alone resulted in high values.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular aspects of the binding of absorbed iron to transferrin

To study the molecular aspects of the binding of absorbed iron to plasma transferrin, 59Fe with high specific activity was administered via intragastric tube to iron-deficient rabbits. The distribution of the absorbed 59Fe among the molecular forms of iron-transferrin was analysed using urea-polyacrylamide gel electrophoresis. Absorbed iron was bound to circulating transferrin one atom at a time. In four out of five animals, absorbed iron was predominantly bound to the site in the N-terminal domain of the protein. Thus, the two sites of transferrin may differ in their ability to load absorbed iron.

In vivo regulation of rat liver 3-hydroxy-3-methylglutaryl-coenzyme A reductase: immunotitration of the enzyme after short-term mevalonate or cholesterol feeding.

In recent studies using either a single dose of mevalonolactone administered by intragastric tube or a single meal containing 2% cholesterol, it was demonstrated that rat liver hydroxymethylglutaryl-coenzyme A reductase [mevalonate: NADP+ oxidoreductase (CoA-acylating), EC 1.1.1.34] (HMG-CoA reductase) the major regulatory enzyme in cholesterol biosynthesis, is subject to two phases of inhibition. The first phase of inhibition is explained by in vivo phosphorylation of the enzyme; however, the nature of the second phase of inhibition remained obscure. The present study tested two possible explanations for this second phase of inhibition--increased enzyme turnover leading to a decreased concentration of HMG-CoA reductase molecules, and further inactivation of existing enzyme molecules. The results with the technique of immunotitration of HMG-CoA reductase show that, in short-term studies conducted up to 2 hr after the administration of a single dose of mevalonolactone or up to 6 hr after a single meal of rat chow containing 2% cholesterol, the in vivo regulation of rat liver HMG-CoA reductase during the first half of the dark period does not occur by increased enzyme turnover but, instead, existing enzyme is further inactivated.

Cerebral dopamine, apomorphine and oral activity in the neonatal pig.

Neonatal piglets in which oral stimulation associated with feeding was reduced by intragastric tube feeding displayed an increase in stereotyped snout rubbing, licking and chewing behaviour. An investigation of a possible neurochemical basis for this behaviour was made by using sensitive radioenzymatic and microfluorimetric assays to estimate the concentrations of the catecholamines and of the dopamine metabolites homovanillic acid (HVA) and 3,4-dihydroxyphenyl-acetic acid (DOPAC) in different brain regions. These observations revealed that the increased non-nutritive oral activity of such piglets did not appear to be caused by an increased release of dopamine in the brain, since it was not associated with increases in the concentrations of the acidic metabolites of dopamine in either the caudate nucleus, the putamen, the nucleus accumbens, the olfactory tubercle, the hypothalamus, or the substantia nigra. The only neurochemical changes observed were small decreases in the concentration of HVA in the putamen and the nucleus accumbens. A lack of effect on catecholamine concentrations in any of the six brain regions examined suggested that the environmental manipulation caused no changes in the development of catecholamine-containing nerve endings. Subcutaneous injection of apomorphine was found to increase the non-nutritive oral activity of piglets. Apparent conditioning effects of the environment on apomorphine-induced stereotyped behaviour however, prevented any satisfactory testing of possible changes in cerebral dopamine receptor sensitivity following reduced oral stimulation.

Gastric fat content and satiety

Male rats were fitted with intragastric tubes and pyloric cuffs. Following a 15 hr food deprivation their intake of a 50% oil-water emulsion was observed to be the same whether the pyloric sphincter was occluded or not. Gastric counterinjections of normal saline (50% of the volume voluntarily drunk) did not affect the amount the subjects drank by mouth. However, when 5 ml of the stomach content was siphoned as the rats drank, an accurate compensation for the amount lost occurred. These findings indicate that the rat is capable of metering gastric triglyceride content and that satiety signals, which are not related to stomach volume, are generated by this organ.

In vivo regulation of rat liver 3-hydroxy-3-methylglutaryl-coenzyme A reductase: enzyme phosphorylation as an early regulatory response after intragastric administration of mevalonolactone.

Although substantial evidence supports the conclusion that 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase [mevalonate:NADP+ oxidoreductase (CoA-acylating), EC 1.1.1.34] is the major regulatory enzyme in cholesterol biosynthesis, the molecular events involved in the in vivo regulation of this enzyme have remained obscure. To study this problem, rats were given a single 100-mg dose of mevalonolactone by intragastric tube. The rats were sacrificed 20 or 60 min later, and liver microsomes were prepared by ultracentrifugation. Two phases of inhibition of microsomal HMG-CoA reductase were observed. The first phase of inhibition, observed 20 min after mevalonolactone administration, was completely reversed by preincubation of the microsomes with purified phosphoprotein phosphatase. The second phase of inhibition, observed 60 min after mevalonolactone administration, was not reversed by phosphoprotein phosphatase. The reactivation of liver microsomal HMG-CoA reductase by phosphoprotein phosphatase was blocked by potassium fluoride or by phosphoprotein phosphatase inhibitor. Results obtained by immunotitration also showed that microsomal HMG-CoA reductase obtained from animals killed 20 min after mevalonolactone administration was significantly activated by phosphoprotein phosphatase treatment of the microsomes. These findings demonstrate that phosphorylation of rat liver HMG-CoA reductase is an early in vivo regulatory response after intragastric administration of mevalonolactone.

Effect of acute ethanol loading on parathyroid gland secretion in the rat.

Acute ethanol loading in the rat induces hypocalcemia and hypermagnesemia. In addition, hypocalcemia is not corrected by exogenous PTH. In the rat the mechanism of these changes was investigated by measuring plasma immunoreactive parathyroid hormone (PTH). PTH was also measured in culture medium in which parathyroid glands were incubated. The addition of ethanol to test tubes did not interfere with PTH measurement. Absolute ethyl alcohol diluted to 50% with distilled water was administered via an intragastric tube. It failed to induce an increase in plasma immunoreactive PTH level. Similarly, it prevented an increase in plasma PTH after disodium EDTA injection. Thus in the presence of ethyl alcohol plasma PTH failed to increase in spite of a significant decrease of plasma calcium. In vitro studies showed that the decrease of calcium concentration of the medium from 1.50 to 0.75 mmol/l was associated with a 3 to 5 times increase in PTH secretion rate. This increase was suppressed when ethanol was added to the culture medium. In conclusion, ethanol loading via gastric tubing induced: 1) decrease in plasma calcium; 2) suppression of immunoreactive PTH secretion in the presence of hypocalcemia. It is postulated that the acute hypocalcemic effect of ethanol loading is mediated by a dual effect at the level of the bone and the parathyroid gland.

Addition of potassium supplements to milk-based tube feeds.

For an intragastric tube feeding regimen to meet the complete nutritional needs of the individual patient, it will often require the addition of extra potassium, to commercially available feeds. Potassium supplements in a suitable form can be added to milk-based feeds to concentrations of at least 175 mmol K+ per litre without any apparent coagulation. Supplements in the form of effervescent preparations are not suitable as the citric-acid content can cause severe coagulation of the feed.

Carcinogenicity of betel quid ingredients: feeding mice with aqueous extract and the polyphenol fraction of betel nut.

Male mice of inbred strains Swiss and C17 were fed daily 5 times a week by intragastric tube 0.1 ml of betel-nut aqueous extract, betel-leaf aqueous extract and the polyphenol fraction of betel nut. Male mice of corresponding strains fed 0.1 ml of distilled water served as controls. Treated and control mice were kept under observation and killed when moribund. Betel-nut aqueous extract induced tumours of the gastrointestinal tract in 58% Swiss mice and 25% C17 mice. The polyphenol fraction by the same route induced tumours at other sites in 17% of the mice. Betel-leaf aqueous extract failed to induce any tumour in the treated mice, which supports an earlier report of the lack of any carcinogenic principle in betel leaf, an essential constituent of betel quid. Results are discussed in relation to the relevant literature.

Simple calculations of volume flow and flow rates across the pylorus

1. (1) Starting from basic principles three linear inhomogeneous equations are derived for the intragastric volume and the two volume markers of gastric contents and duodenal contents respectively. From these the intragastric volume secreted, the volume refluxed from the duodenum, and the gastric volume emptied can be calculated simultaneously. 2. (2) Looking at the net changes in intragastric marker quantities during a short time interval two linear inhomogeneous equations are derived. From these flow rates across the pylorus can be calculated. 3. (3) Two kinds of experiments are suggested to measure flow rates: The first radioactive marker is given together with the test meal, the second marker (i.e. 99mTc-Hepatobida R is infused intravenously and excreted with the bile into the duodenum. A gamma camera records the radioactivities over two regions of interest (stomach and duodenum) at short time intervals. Flow rates across the pylorus are calculated from total counts measured. 4. (4) Assuming that (i) total amount of duodenal marker remains constant at steady state conditions and (ii) reflux of gastric marker is negligible compared with its intragastric contents the same technique for measuring flora rates applies with an intragastric tube only.

An evaluation of the influence of increased gastric acid in the aetiology of reserpine-induced ulcers in rat stomachs

Summary Reserpine (5 mg/kg), injected i.p. 4 h before sacrifice, produced mucosal ulcers in both the rumenal and glandular portions of pylorus-occluded rat stomachs. These effects were accompanied by increased gastric acid and secretory volume, stomach wall mast cell degranulation, and increased microcirculatory blood volumes in the superficial third of the glandular mucosa. Concomitant neutralisation of gastric acid with sodium bicarbonate (100 mg), given by intragastric tube immediately after pylorus occlusion and before reserpine injection, markedly prevented rumenal but not glandular ulcer formation. Gastric acid neutralisation did not affect mast cell degranulation or the mucosal microcirculatory changes produced by the drug. These findings suggest that the microcirculatory changes are more likely to result directly from mast cell degranulation, rather than indirectly from the action of increased luminal acid. They also provide more evidence to indicate that reserpine-induced rumenal ulceration depends chiefly on the presence of luminal gastric acid, whereas glandular ulcer formation could be mainly the consequence of mucosal vascular dilatation and congestive ischaemia produced by gastric mast cell histamine release.