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Biomedical subjects

L Rodríguez

Publications and source records attributed to L Rodríguez.

At least 109 records · Page 6Linked to original sources
PubMed1987

Coordinated regulation of ammonium assimilation and carbon catabolism by glyoxylate in Saccharomyces cerevisiae.

The activities of citrate synthase (EC 4.1.3.7) and NADP+-dependent glutamate dehydrogenase (GDH) (EC 1.4.1.4) of Saccharomyces cerevisiae were inhibited in vitro by glyoxylate. In the presence of glyoxylate, pyruvate and glyoxylate pools increased, suggesting that glyoxylate was efficiently transported and catabolized. Pyruvate accumulation also indicates that citrate synthase was inhibited. A decrease in the glutamate pool was also observed under these conditions. This can be attributed to an increased transamination rate and to the inhibitory effect of glyoxylate on NADP+-dependent GDH. Furthermore, the increase in the ammonium pool in the presence of glyoxylate suggests that NADP+-dependent GDH was being inhibited in vivo, since the activity of glutamine synthetase did not decrease under these conditions. We propose that the inhibition of both citrate synthase and NADP+-dependent GDH could form part of a mechanism that regulates the internal 2-oxoglutarate concentration.

Carbon↗
PubMed1987

[Preparation of frozen blocks of fish flesh and its evaluation during storage].

Minced fish flesh from shrimp by-catch was used as raw material to prepare four frozen blocks under different conditions, as follows: a) Minced fish flesh washed in cool water for 10 minutes with continuous stirring (water-fish proportion, 3:1). b) Minced fish flesh mixed with sodium tripolyphosphate (TPP) (0.5%), and sodium chloride (1%), respectively. c) Minced fish flesh mixed with 0.5% sodium tripolyphosphate, 1% sodium chloride and 7.5% corn starch, and c) Minced fish flesh without any treatment, which was used as control. Fish blocks were frozen at -40 degrees C and stored at -10 degrees C and -30 degrees C freezing points during a six-month period. Physical, chemical and microbiological tests were performed during the storage period. The results obtained indicate that frozen fish blocks stored at -10 degrees C deteriorate faster than those stored at -30 degrees C. The TPP, sodium chloride and corn starch treatments were not effective in reducing protein denaturation, but they do increase the water retention capacity of the blocks.

Animals↗
PubMed1986

Pharmacological properties of droxicam, a new non-steroidal anti-inflammatory agent.

Droxicam showed high antiinflammatory activity in carrageenin-induced edema in rat. At doses of 0.25 and 0.5 mg/kg, droxicam was as active as piroxicam and more active than phenylbutazone given at 2.5 and 5 mg/kg. Against nystatin-induced edema, droxicam (ED50, p.o., 5, 6, 7, 8 h: 7.5, 12.9, 4.8, 8.4 mg/kg) was 4-11 times more active than phenylbutazone and more than 12 times more active than isoxicam. In cotton pellet-induced granuloma in rats, title compound was as active as suprofen. In U.V. light-induced erythema in guinea pigs, droxicam (ED50, p.o., 1, 2, 3, 4 h: 0.51, 0.94, 1.56, 4.88 mg/kg) was 5-9 times more active than phenylbutazone. At doses of 0.1, 0.33 and 1.0 mg/kg/day, droxicam, similar to piroxicam, showed good antiarthritic activity in rats injected with Mycobacterium butyricum against primary and secondary lesions. Droxicam demonstrated strong analgesic activity in protecting against writhings: induced by phenylbenzoquinone in mice: ED50: droxicam = 5.3, phenylbutazone = 61.5, acetylsalicylic acid = 90.7, dipyrone = 83.6, isoxicam = 88.3 mg/kg, p.o.; induced by acetylcholine bromide in mice: ED50: droxicam = 1.1, phenylbutazone = 32.1, acetylsalicylic acid = 32.2, isoxicam = 32.7 mg/kg, p.o.; induced by acetic acid in rat: ED50: droxicam = 0.94, acetylsalicylic acid = 8.72, isoxicam = 4.70 mg/kg, p.o. Antipyretic activity of title compound was demonstrated in rats with pyresis induced by brewer's yeast, being 4-13 times more active than dipyrone. In pyresis induced by Salmonella typhi, droxicam was more active than acetylsalicylic acid and 4-aminoantipyrine at all times and doses. In a study of protection against diarrhea induced by castor oil in rats, droxicam and piroxicam showed equal activity (ED50 = 0.081 and 0.079 mg/kg, p.o., respectively) and were 3.9 and 15.6 times more active than isoxicam and phenylbutazone, respectively. Droxicam significantly inhibited peritoneal capillary permeability in mice at a dose of 5 mg/kg, p.o., while isoxicam and phenylbutazone required 100 and 200 mg/kg, p.o., respectively. Droxicam did not exhibit uricosuric activity in rats. It did not show cardiovascular or respiratory effects in anesthetized cats, nor modify their response to administration of acetylcholine, norepinephrine and histamine. In the Irwin's test, droxicam did not alter rat behavior (80 mg/kg, i.p.) nor that of mice (160 mg/kg, p.o.). Induction of gastrointestinal injuries in rats by droxicam was 10 times less than by piroxicam (UD50: droxicam, 57 mg/kg, p.o.; piroxicam, 5.6 mg/kg, p.o.). The potentiation of gastric injuries induced by stress through cold in rats was also studied.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Subcellular localization and glycoprotein nature of the invertase from the fission yeast Schizosaccharomyces pombe.

The subcellular localization of the enzyme invertase in Schizosaccharomyces pombe cells, both repressed and derepressed for synthesis of the enzyme, was studied. Most of the invertase was found to be located outside the plasma membrane and only a small percentage was found to be associated to membranes. A substantial portion of the external enzyme remained firmly bound to cell-wall material. All of the invertase recovered in soluble form from cellular extracts reacted with concanavalin A and with the lectin from Bandeiraea simplicifolia seeds, indicating the presence in the enzyme of a carbohydrate moiety which probably contains terminal mannosyl (or structurally related) and galactosyl residues. The possibility of the presence of two different forms of invertase in S. pombe was considered. An intracellular, soluble form of invertase, devoid of carbohydrate, similar to the small invertase of the budding yeast Saccharomyces cerevisiae, was not found in S. pombe. However, the Michaelis constant for sucrose of the enzyme present in repressed cells was smaller than that of the invertase synthesized under derepressing conditions, although this difference could also be the result of a different pattern of glycosylation of the invertase synthesized under different growth conditions.

Electrophoresis, Polyacrylamide Gel↗
PubMed1985

NADP+-dependent glutamate dehydrogenase activity is impaired in mutants of Saccharomyces cerevisiae that lack aconitase.

A mutant of Saccharomyces cerevisiae lacking aconitase did not grow on minimal medium (MM) and had five- to tenfold less NADP+-dependent glutamate dehydrogenase (GDH) activity than the wild-type, although its glutamine synthetase (GS) activity was still inducible. When this mutant was incubated with glutamate as the sole nitrogen source, the 2-oxoglutarate content rose, and the NADP+-dependent GDH activity increased. Furthermore, carbon-limited cultures showed a direct relation between NADP+-dependent GDH activity and the intracellular 2-oxoglutarate content. We propose that the low NADP+-dependent GDH activity found in the mutant was due to the lack of 2-oxoglutarate or some other intermediate of the tricarboxylic acid cycle.

Aconitate Hydratase↗
PubMed1984

Influence of carbon catabolite repression on the G1 arrest of Saccharomyces cerevisiae MATa cells by alpha factor.

Cells of the yeast Saccharomyces cerevisiae of the a mating type were arrested at the G1 phase of the cell division cycle after treatment with alpha factor in a culture medium containing a high concentration (2%, w/v, or higher) of a catabolite-repressing sugar. In media containing either a lower concentration of sugar or a non-fermentable carbon source, the extent of G1 arrest induced by the pheromone was reduced or became undetectable. Under catabolite-derepressing conditions alpha factor was inactivated by a cells at a higher rate than that found in repressing media. These results indicate the existence of a close correlation between the action of alpha factor on a cells and conditions of catabolite repression or derepression. A joint mechanism of action of alpha factor and catabolite-repressing carbon sources on a cells is postulated.

Enzyme Repression↗
PubMed1984

[A simple method for reviewing the curriculum of the Nutrition Program of the University of Costa Rica].

The article explains that, in drawing up and reviewing the Nutrition Program of the University of Costa Rica, it was viewed as important to determine the kind of professional to be produced. To find the answer, the methodology proposed in 1974 by Segall and associates for systematic course design was adopted. Based on the country's needs, two specific posts were described that should be filled with priority: Chief of a food service, and chief of the nutrition program in a health region. Professionals in each of those fields collaborated in defining the duties of each post and the skills, knowledge and attitudes required to enable a nutritionist to perform them well. The resulting list is distributed for each course and used as a basis for defining the aims of the Program and its courses.

Costa Rica↗
PubMed1981

[Neonatal septic arthritis. Our experience in 14 cases (author's transl)].

A survey was carried out from october 1973 to december 1979 of fourteen newborn who presented septic arthritis secondary to sepsis, developed during their admission at our neonatology unit. Authors point out the high incidence of Klebsiella as the organism isolated in 48% of the positive cultures and the good response to general and local treatments. A discussion is done on the sequels and their long-term evolution.

Arthritis, Infectious↗
PubMed1980

Regional changes in phenylethanolamine-N-methyltransferase of rat brain during development.

The changes of phenylethanolamine-N-methyltransferase (PNMT, EC 2.1.1.28), the enzyme that catalyzes the final step in the biosynthesis of adrenaline, were studied during the development of several regions of rat brain. PNMT is present in medulla oblongata-pons, hypothalamus, cerebellum, and midbrain five days before birth, and a progressive increase in the enzyme activity is observed during development. The adult levels are attained between 15 and 20 days, depending on the region. The increases in PNMT activity in the rostral regions are higher than in the caudal regions. PNMT attains adult levels earlier than tyrosine hydroxylase and dopamine-beta-hydroxylase. The apparatus for adrenaline synthesis seems to be mature at three weeks after birth in the medulla oblongata-pons, which contains the cell bodies of adrenaline-containing neurons. In the other regions the adult levels of enzyme activity are attained at 15 days after birth.

Aging↗
PubMed1979

[Cancer of the alpha cells of the pancreas].

Endocrine tumors of the pancreas are rare. One of them is the so called alpha cell carcinoma also called glucagonoma usually associated with diabetes and skin lesions somewhat typical. A case of a male patient fifty-three years of age with clinical diabetes mellitus and generalized dermatitis is presented. The pancreatic scan showed some enlargement of the head of the pancreas as well as the body which was confirmed by ultrasound. Angiography showed that this change was due to pancreatic tumor with intrahepatic metastasis. The patient was taken to surgery where a glucagonoma of the pancreas was found. This case is reported because only 32 other cases have been reported in the literature.

Adenoma, Islet Cell↗