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I C Terra

Publications and source records attributed to I C Terra.

10 recordsLinked to original sources
PubMed1996

Dietary nitrite and scavenger antioxidants trace elements.

Rats initially weighing 138 +/- 14 g were fed the following diets for 150 days: control (Co), control plus nitrite-bacon-proline 24 mg/kg, 100 g/kg and 10 mg/kg, respectively (NB), NB plus 0.04 micrograms/g selenium (NBSe) and NB plus 0.020 g/kg ascorbic acid (NBC). The NB diet provoked body weight and feeding efficiency enhancement with a reduction in body density increasing serum lactic acid, uric acid and cholesterol levels. The serum selenium decreased by the presence of NB in the diet. The addition of selenium and ascorbic acid to the NB diet prevented the reduction in body density and also affected uric acid and cholesterol levels. It is suggested that the NB diet has adverse effects and that some of the alterations it causes are prevented by the reducing elements selenium and ascorbic acid.

Animals↗
PubMed1995

Effects of dietary fat and nitrite on plasma and corporal density.

Two groups of nine weanling male rats each were fed different diets for 60 days. Group A (control) was fed a full casein diet containing 17% protein. The group B received the same diet plus nitrite, fried bacon and proline. Diet B induced increased body weight gain and increased plasma l-lactic acid and cholesterol levels, as well as a decrease in plasma selenium. We suggest that the adverse effects of diet B are related to peroxidation, with an increased nutritional need for selenium.

Animals↗
PubMed1983

Inhibition of an insect midgut trehalase by dioxane and delta-gluconolactone: enzyme pKa values and geometric relationships at the active site.

1. Inhibition of the Rhynchosciara americana midgut trehalase (alpha, alpha'-trehalose glucohydrolase, EC 3.2.1.28) by the competitive inhibitor dioxane have been studied. 2. Determinations of the Ki of dioxane at different pH provided the true pKa values of the prototropic groups of the trehalase active site (pKa 5.2 and 8.2), which are in agreement with those determined previously from kinetic and chemical modification data. 3. Dioxane only changes the enzyme pKa values if bound at the enzyme active site. 4. Gluconic acid does not inhibit the trehalase, in contrast to delta-gluconolactone which is a simple intersecting linear inhibitor. 5. Multiple inhibition analyses showed that delta-gluconolactone and Tris bind at the same site in the trehalase active center, whereas dioxane binds closer to delta-gluconolactone than to Tris. 6. The data support the assumption that dioxane binds at the middle portion of the trehalase active site.

Animals↗
PubMed1983

Corn amino acid imbalance and the role of leucine excess.

A study was conducted using two experimental models with weanling rats of the Wistar strain fed isocaloric diets containing 7% protein, Model I: two genetic varieties of maize were used; common corn (CC) or opaque-2-corn (M); and Model II: casein, 7% protein used without nicotinic acid in the diet in order to enhance the tryptophan limiting conditions like in the CC diet of Model I. PER, nitrogen balance, urinary urea and hepatic fat were determined. The results suggest that the imbalance of CC protein is related to lysine and tryptophan limitation, although the leucine excess content also plays an important role.

Amino Acids↗
PubMed1979

Carbodiimide-reactive carboxyl groups at the active site of an insect midgut trehalase.

Carbodiimide modification of the Rhynchosciara americana midgut trehalase (alpha, alpha-trehalose glucohydrolase, EC 3.2.1.28) at different pH values revealed the existence of two essential groups (pKa 5.28 and pKa 7.74) for the trehalos activity. Those groups must be carboxyl groups since the alternative possibilities (sulfhydryl and phenol groups) have been discarded by selective modification and attempts to reactivate the modified enzyme with hydroxylamine. Furthermore, the increase of the pKa values of carbodiimide-reactive groups in the presence of dioxane supports further evidence that they are carboxyls. The results suggest the pKa 5.28 carboxyl is in the active site, while the pKa 7.74 carboxyl is in its neighborhood buried in the enzyme molecule. The possible role for the carbodiimide-reactive carboxyl groups in catalysis is discussed.

Animals↗
PubMedDate not supplied

Enhancement of sodium intestinal secretion in relation to absorption in malnourished rats. Hyperosmolar challenge.

Two experimental models were tried in young malnourished rats in order to study effect of an hyperosmolar challenge in the small intestine on the bi-directional fluxes of sodium. Weanling rats were fed with energy restricted diets. In model I 1 mL of NaCl 900 mOsm/kg was introduced in the small intestine of the rats and left from 5 up to 70 min, in order to determine the moment of higher net Na+ secretion, which occurred at 10 min. In model II, the bi-directional fluxes of Na+ and Cl- were studied using NaCl or mannitol 900 mOsm/kg under the effect of mecholil, atropine or 2-4 dinitrophenol, for 10 min. Mecholil decreased the Na+ absorption enhancing the net secretion. Control rats were used as reference. In the restricted diets animals occurred an increase of the net secretion stimulated by NaCl 900 mOsm/kg, and this effect was enhanced by mecholil. It is suggested that in malnutrition there is an impairment in Na- intestinal absorption.

Animals↗
PubMedDate not supplied

Imbalanced protein and appetite.

Free amino acid concentration in the plasma of rats fed on different diets were compared. The diets contained 7 g protein/100 g furnished by: casein, or common corn, or opaque 2 corn, or eggalbumin, or gelatin. A protein free diet was also included. The results showed that imbalance of the protein diet influenced the appetite; whenever the NE/E aminoacid ratio increased, body development, appetite and plasma albumin decreased. An inverse correlation between the NE/E of free aminoacids of the plasma and voluntary intake was observed. The results also show that the plasma aminogram did not reflect the composition of the protein in the diet. The results obtained are discussed.

Animals↗
PubMedDate not supplied

[Effect of lactose ingestion on body development. Study in rats].

Dams (rats) and their offsprings were fed on diets containing casein (Cas) or rice and beans (RB) as protein source. The presence of lactose improved the whole animal as well as the intestinal development in Cas diet but not from RB ones. It is suggested that lactose must be maintained permanently in diet but in low concentration. In this investigation it was also observed that the small intestinal development occurs initially by enhancement of length and weight, while after weaning only weight continues to increase independently of the presence or not of lactose in diet.

Animals↗
PubMedDate not supplied

Lactose load diet effect in rats.

Weanling and young adult rats were fed diets containing lactose (L) up to 50 g per 100 g diet for 15 days. The growth rats variation (W), fecal pH, net protein ratio (NPR) and protein efficiency ratio (PER) were determined. In weanling as well as in young adult rats an impairment of L was only detected for higher levels (greater than 20%), and diarrhea occurred only at 50%. The NPR and PER were partially effected by L because of the stimulation of appetite between 1 and 5 g%. The results for 10 and 20 g% of L were not different from controls. It was concluded that rats are not intolerant to levels of L less than or equal to 20%. The evaluation of protein quality in presence of L must be conducted with adapted methodology.

Animals↗