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Biomedical subjects

A Blanco

Publications and source records attributed to A Blanco.

At least 181 records · Page 10Linked to original sources
PubMed1986

Properties of the branched-chain 2-hydroxy acid/2-oxo acid shuttle in mouse spermatozoa.

Operation of the branched-chain 2-hydroxy acid/2-oxo acid shuttle for the transfer of reducing equivalents in mitochondria of mouse spermatozoa was studied in vitro in reconstituted systems. Results show that the branched-chain 2-oxo acids within the mitochondria are offered several metabolic pathways. (a) Decarboxylation: mouse sperm mitochondria possess high branched-chain 2-oxo acid decarboxylase activity. (b) Recycling to the cytosol by using a transport system which can be inhibited by alpha-cyano-3-hydroxycinnamate and pH 6.8. (c) Transamination to the corresponding amino acids: experiments presented indicate that leucine formed from 4-methyl-2-oxopentanoate may pass to the external phase, re-initiating the cycle. These two last possibilities would allow autocatalytic operation of the shuttle. The branched-chain 2-hydroxy acids apparently do not utilize the monocarboxylate carrier to penetrate the mitochondria.

Animals↗
PubMed1986

In vitro inhibition by gossypol of oxidoreductases from human tissues.

The effect of gossypol, a polyphenolic compound with antifertility action on human males, has been investigated on the following oxidoreductases purified from human tissues: lactate dehydrogenase (EC 1.1.1.27) isozymes 1 or B4 from heart, 5 or A4 from liver and X or C4 from spermatozoa; malate dehydrogenase (EC 1.1.1.37) mitochondrial and "soluble" isozymes from heart and NADP-glutamate dehydrogenase (EC 1.4.1.4) from liver. Gossypol proved to be a powerful inhibitor of the six enzymes studied. For all of them, inhibition was of the competitive type with respect to the coenzyme and non-competitive in relation to substrate. The lowest ki values were shown for lactate dehydrogenase isozyme 1 or B4 and for the two isozymes of malate dehydrogenase. Results did not show selectivity of gossypol for the sperm-specific isozyme X or C4 of lactate dehydrogenase.

Glutamate Dehydrogenase↗
PubMed1986

Lactate dehydrogenase X, malate dehydrogenase and total protein in rat spermatozoa during epididymal transit.

Lactate dehydrogenase isozyme X (LDH X), malate dehydrogenase (MDH) and total soluble protein have been determined in lysates of spermatozoa isolated from caput, corpus and cauda of rat epididymis. Transit of spermatozoa through epididymis is accompanied by a reduction of LDH X, MDH and total protein per cell in sexually rested animals. The profiles of reduction along epididymal segments are different for the three variables studied. Mating with receptive females during the 5 days prior to determinations increases significantly the levels of MDH in spermatozoa from all sections of epididymis and produces increase of total soluble protein in the cells contained in cauda.

Animals↗
PubMed1986

[Chemical composition and evaluation of the protein quality of beans in adult humans by the short-term nitrogen balance method].

Three varieties of common beans were chemically analyzed and their protein quality was evaluated in 12 human male adult subjects by the short-term nitrogen balance method. Chemical analyses were performed for both raw and cooked grains. Cooking reduced the trypsin inhibitors in 28 to 73%, hemagglutinins, 100%, tannins as acid tannic equivalents, 9 to 72%, and 55 to 75% as catequin equivalents, and alkali-soluble nitrogen in 65%. Red and black beans contained more residual trypsin inhibitors and tannins than white beans, while the latter contained more alkali-soluble nitrogen. Although cooked colored beans had more antinutritional factors that affect protein digestibility, their protein quality was similar to that of white beans. This could be explained by the fact that the amino acid composition and/or balance of red and black beans absorbed nitrogen is better than that of white beans, so that the final nutritional value will be determined by the sum of interactions between all factors. In this study, each of the three varieties presented at least one protein quality depressor in higher concentration than the other two varieties. Therefore, the overall differences found between treatments and residual effect, were small or non existent, while significant differences (p greater than 0.05) were found between subjects and nitrogen balance periods. A level of 0.65 g of bean protein/kg/day was not enough to maintain nitrogen balance in subjects fed a diet where beans were the only protein source. According to calculations, 0.9-1.0 g of bean protein/kg/day are necessary for nitrogen balance in male adults, and 1.2-1.3 g of protein bean would be the recommendation for a normal population.

Adult↗
PubMed1985

[Leukemic infiltration in the anterior chamber of the eye].

Leukaemic infiltration of the anterior chamber of the eye (hypopyon and corneal opacity) was the only sign of relapse in two girls with acute lymphoblastic leukaemia who had been off treatment for one and three years. The malignant cells had probably been present in the eye since the onset of the disease. The anterior segment of the eye may be a pharmacologycal "sanctuary" in patients with ALL. The response to radiotherapy was good but this treatment should be coupled with systemic chemotherapy and CNS prophylaxis.

Anterior Chamber↗
PubMed1985

Changes of intestinal alkaline phosphatase produced by cholecalciferol or 1,25-dihydroxyvitamin D3 in vitamin D-deficient chicks.

Treatment with cholecalciferol or 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) increases activity and changes electrophoretic mobility of alkaline phosphatase (alkPase) from duodenal brush border of vitamin D-deprived chicks. Three of the four molecular forms of the enzyme show reduced velocity of migration 9 h after 1,25(OH)2D3 or 24 h after vitamin D3. This change is reversed about 48 h later, when mobility of those bands is higher than that of controls. Incubation of enzyme preparations with exogenous neuraminidase produces the same electrophoretic modifications observed during the early stage, indicating that they are due to desialylation. Cholecalciferol or 1,25(OH)2D3 increase sialidase activity of duodenal brush border. This increment precedes that of alkPase and could account for the initial desialylation and moderate rise of alkPase. Cycloheximide markedly reduces alkPase in rachitic chicks and blocks the increase of the enzyme activity produced by vitamin D3, but does not modify the rise of sialidase or the reduction of alkPase electrophoretic mobility. The bimodal response of alkPase to 1,25(OH)2D3 or cholecalciferol comprises two different mechanisms: during a first stage, epigenetic modifications of preexisting enzyme can be triggered by the increased Ca2+ levels; in a second phase, there is activation of enzyme synthesis.

Alkaline Phosphatase↗
PubMed1985

Increased serum beta2-microglobulin levels in active celiac disease.

Sixty-eight sera from 36 children with celiac disease (CD) were collected in a 4-year study, and the levels of beta2-microglobulin (beta2M), orosomucoid, alpha1-antitrypsin, and C-reactive protein (CRP) were measured. A simultaneous intestinal biopsy was taken in all the patients and used to classify them. The values of beta2M were 1.94 +/- 0.49 mg/L in group A (inactive CD with normal intestinal biopsy) and 2.58 +/- 0.76 mg/L in group B (active CD with flat mucosa). These levels were higher than in the normal controls (1.87 +/- 0.49 mg/L, p less than 0.005) and in the other 19 patients with chronic diarrhea of another cause (1.72 +/- 0.63 mg/L, p less than 0.005). CRP values were generally normal; orosomucoid and alpha1-antitrypsin were variable and they did not correlate with beta2M levels. Beta2M was increased at the time of diagnosis in seven of eight (87.5%) of the CD children and only in three of 19 (15.7%) of nonceliac patients with chronic diarrhea of another cause (p less than 0.005). In 12 children with CD, serial studies were possible. The highest beta2M level coincided with a flat mucosa in 10 cases. The increase of beta2M could be related to the intestinal infiltration or even to the lymphocyte activation. It may also be a useful noninvasive method for evaluating the activity of CD.

Acute-Phase Proteins↗
PubMed1985

Genetic polymorphism in populations of Akodon rodents.

By means of starch gel electrophoresis, 16-20 loci coding for enzymes and hemoglobin have been investigated in six population samples of Akodon dolores, captured in a single site of the Córdoba province (Argentina) during a 3-year period and in three samples of an Akodon azarae population. Proportion of polymorphic loci (P) ranged from 0.278 to 0.389 in A. dolores and from 0.166 to 0.300 in A. azarae. Mean heterozygosity (H) ranged from 0.138 to 0.192 in A. dolores and from 0.099 to 0.118 in A. azarae. These values are very high compared with those reported for northern hemisphere rodent populations. The high value is remarkable since the loci sample is biased towards the less variable (group I) enzymes.

Animals↗
PubMed1985

[Biological evaluation of an infant food based on soybean, rice and banana].

An infant food, a mixture of soy, rice and banana was biologically evaluated in three studies carried out in Sprague-Dawley rats. In the first assay, the caloric supplementation and milk protein complementation effect on the nutritive value of the product was studied. Results indicated that an equal nutritive value as that of milk is obtained when 50% of the vegetable protein is replaced by animal protein. The fact that caloric supplementation does not exert any positive effect on the nutritive value of the infant food, under the conditions of the study, was also confirmed. In the second assay, the effect of amino acid (lysine and methionine) supplementation was evaluated. Results revealed a significant improvement of the product quality with lysine supplementation, a finding that implies thermal protein damage caused by industrial processing. In the third study, whole milk supplementation effect at the levels that the product could be offered in school lunch programs and Nutrition and Education Centers was investigated. Such values, as determined, correspond to 343 to 655 ml of fluid milk per 100 g of the cereal product. It was also found that milk complements and improves the nutritive value of the product at equal statistical (P less than 0.05) values as those of milk.

Animals↗
PubMed1985

[Risk factors in the development of idiopathic pulmonary hemosiderosis].

A long-term study of six children suffering idiopathic pulmonary hemosiderosis (IPH) was realized, in order to evaluate prognostic factors and the best therapy. The treatment was initiated with prednisone 1-2 mg/kg/day which was gradually decreased until total suppression. Clinical remission was always achieved but relapses were frequently observed. All but one of the patients suffered more episodes which were controlled by the initial treatment. In three cases the additional use of immunosuppressors drugs was needed, chlorambucil 0.2 mg/kg/day during a period of 3-6 months or cyclophosphamide 2.5 mg/kg/day for four months, thereby obtaining a better control of the disease and also a decreased number of crises. Two patients died during acute exacerbations. It is suggested that the main risk factors are the male sex and onset before three years of age. The outcome was also worse when the first crisis was more severe.

Child↗
PubMed1984

Inhibition by gossypol of oxidoreductases from Trypanosoma cruzi.

The effects of gossypol, a polyphenolic compound isolated from the cotton plant upon six oxidoreductases from cultured epimastigotes of Typanosoma cruzi were studied. Gossypol was a powerful inhibitor of the alpha-hydroxyacid and malate dehydrogenases, NAD-linked enzymes, and of glutamate dehydrogenase, malic enzyme and glucose-6-phosphate dehydrogenase, NADP-dependent enzymes. The drug did not have an effect on succinate dehydrogenase, a flavoprotein. The Ki values with respect to substrate were 0.73, 0.3 and 3.5 microM for alpha-hydroxyacid, malate and glutamate dehydrogenases, respectively, and 1.1, 0.19 and 7.8 microM with respect to the coenzyme. Inhibition was noncompetitive with respect to substrate and uncompetitive in relation to the coenzyme.

Alcohol Oxidoreductases↗
PubMed1984

Genetic similarity between species of Akodon (Rodentia, Cricetidae).

Genetic similarity between species of rodents of the Akodon genus (A. dolores, A. molinae, and A. azarae) has been estimated by analysis of electrophoretic zymograms corresponding to 23 loci. Nei's coefficient between A. dolores and A. molinae was within the range usually found in conspecific populations. This evidence plus the successful production of "hybrids" (Merani et al., J. Exp. Zool., 206:343-346, '78) suggests that A. dolores and A. molinae may represent geographic races of the same species.

Animal Population Groups↗
PubMed1984

Effect of temperature upon catalytic properties of alpha-hydroxyacid dehydrogenase from Trypanosoma cruzi.

A comparative study of the effect of temperature (10, 20, 30 and 37 degrees C) upon Km and V of alpha-hydroxyacid dehydrogenase (HADH), isozyme I and II, from Trypanosoma cruzi, a parasite whose life cycle comprises stages in an insect vector, and of another enzyme with analogous substrate specificity, the lactate dehydrogenase, isozyme X (LDH X) from mouse, a homeotherm, is presented. The Km for alpha-ketoisocaproate of HADH is markedly reduced as temperature decreases. This effect can compensate the reduction in thermal energy and produce stabilization of the reaction rate. This compensation does not occur with mouse LDH X. The activation energy for both HADH isozymes is about half the value determined for mouse LDH X. Results indicate that HADH from T. cruzi is able to adjust instantaneously to thermal changes of the environment, behaving as other enzymes of terrestrial poikilothermic animals.

Alcohol Oxidoreductases↗
PubMed1984

Circadian rhythm of lactate dehydrogenase in rat testis.

Activity of total lactate dehydrogenase (LDH) and of the isozyme X (LDH X or C4) have been determined at 2 hr intervals during 24 hr cycles in testis of adult rats maintained since birth in a photoperiod of 14 hr light: 10 hr dark. LDH X activity of epididymal sections (caput, corpus and cauda) from the same animals was also determined. Total LDH and LDH X activities in testis exhibited circadian rhythms with different timing. LDH X in the three portions of epididymis showed diurnal variations similar to those in testis. Rats subjected to constant light or constant dark presented marked modifications of LDH X profiles, indicating that the photoperiod plays a synchronizer role. While total soluble proteins did not show variations in testis of rats exposed to the photoperiod, a circadian rhythm was demonstrated in animals maintained in constant light or dark.

Animals↗