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Biomedical subjects

R Ramírez

Publications and source records attributed to R Ramírez.

At least 91 records · Page 5Linked to original sources
PubMed1992

[Epidemiologic study of factors associated with hypospadias].

From August 60 to December 90, 103 male newborns with hypospadias were diagnosed among 124 588 consecutive newborns examined (8.3 per 10,000). Mortality among them was 1.94%. The annual incidence rate increased significantly over the study period (p < 0.001. Hypospadias was an isolated finding in 92% of cases, and its was associated to other non genital malformation in 8.7%. Location of hypospadias was distal in 73% and proximal in 15.5%. There was no seasonal variation in the incidence rate. Weight of affected individuals did not differ from that of controls. Older age of parents among affected individuals was not statistically significant.

Abnormalities, Multiple↗
PubMed1991

Collagenase and collagenase inhibitors in bronchoalveolar lavage fluids.

Collagenase, collagenolytic activity and tissue inhibitor of metalloproteinases were evaluated in bronchoalveolar lavage from 25 patients with hypersensitivity pneumonitis and four control subjects. Patients were followed between two and three years, after which they were classified as "healed," "improved," or "worsened." In control samples, immunoreactive collagenase was not detected. The enzyme was present in four of seven patients who healed, six of ten patients who improved, and four of eight patients who worsened. There was no relationship between the presence or absence of BAL collagenase or its concentration and the evolution of the disease. Latent collagenolytic activity was detected only in 5 of the 14 patients who displayed immunoreactive collagenase. Regarding collagenase inhibitor, TIMP was present in BAL fluid from all patients and normal subjects. Although the highest values were found in two cases who healed or improved, there was not a statistically significant difference among the three groups of patients, neither between patients nor control subjects. These findings suggest that at least in HP, the presence of collagenase, collagenolytic activity, or TIMP in BAL fluid is not associated with the prognosis of the disease.

Adult↗
PubMed1991

[Increase of incidence of Down syndrome and its possible relation with increased maternal age].

Among 47,458 consecutive births taking place between july 1977 and december 1989, we found 83 newborns with Down syndrome, for a 1.74/1000 live births incidence rate. This compares to a rate of 1.39 rate observed at the same maternity from 1971 to 1977 (NS). The mean age of all mothers was 25.9 years as compared to 31.87 for mothers of children with Down syndrome (p < 0.00001). The mean maternal age has increased from 24.34 in 1977 to 27.38 in 1988 (p < 0.0001), mostly due to a greater proportion of the 25 to 29 year-old group of mothers. These data support, although not conclusively, that the increased incidence of Down syndrome in our population is related to older maternal age.

Adolescent↗
PubMed1990

[Incidence of malformations of the central nervous system: 1978-1988].

During the period Jan 1978 to Dec 1988, 41,867 deliveries took place at the University of Chile Hospital. Among them, 148 babies were found to have malformations of the central nervous system, an incidence of 3.6 per 1000 live births. A longitudinal study from 1969 to 1988 suggests a yearly increment of 0.1% in the incidence rate of these malformations. The comparison of some quantitative variables, such as gestational age, birthweight, number of previous abortions and some risk factors like maternal illness, bleeding, radiation exposure, drug ingestion during the first trimester of pregnancy and instructional level of both parents show significant differences between the malformed and the control newborns. No significant differences were found for maternal age, sex nor seasonal variation.

Abnormalities, Drug-Induced↗
PubMed1988

Role of menaquinone in inactivation and activation of the Bacillus cereus forespore respiratory system.

The respiratory systems of the Bacillus cereus mother cell, forespore, and dormant and germinated spore were studied. The results indicated that the electron transfer capacity during sporulation, dormancy, and germination is related to the menaquinone levels in the membrane. During the maturation stages of sporulation (stages III to VI), forespore NADH oxidase activity underwent inactivation concomitant with a sevenfold decrease in the content of menaquinone and without major changes in the content of cytochromes and segment transfer activities. During the same period, NADH oxidase and menaquinone levels in the mother cell compartment steadily decreased to about 50% at the end of stage VI. Dormant spore membranes contained high levels of NADH dehydrogenase and cytochromes, but in the presence of NADH, they exhibited very low levels of O2 uptake and cytochrome reduction. Addition of menadione to dormant spore membranes restored NADH-dependent respiration and cytochrome reduction. During early germination, NADH-dependent respiration and cytochrome reduction were restored simultaneously with a fourfold increase in the menaquinone content; during germination, no significant changes in cytochrome levels or segment electron transfer activities of the respiratory system took place.

Bacillus cereus↗
PubMed1987

[Yield and chemical composition of the vegetal parts of the amaranth (Amaranthus hypochondriacus, L.) at different physiological stages].

The genus Amaranthus comprises species which, consumed as vegetables, provide essential nutrients to man; they also have a high acceptability among the population. These two factors justify the need to increase their cultivation. Therefore, the purpose of this research was to establish the most adequate physiological state of maturity, to harvest the leaves for human consumption. The field experiment utilized a randomized block design with three treatments and eight replications. These treatments consisted in harvesting the plants at 25, 40 and 60 days after emergence of the seedlings, samples which served to evaluate: plant height, number of leaves, leaf surface area, gross weight (leaves and stems), net weight (leaves), green matter and dry matter yield, as well as protein. The chemical composition of the harvested material was evaluated also in terms of moisture, protein, crude fiber, ether extract, ash, carbohydrate, calcium, phosphorus, iron, beta-carotene and oxalates. The results obtained in the agronomic study were subjected to analysis of variance for the respective design, with significant differences found between treatments for all the variables studied. In its turn, the results of the chemical analysis were analyzed by a completely randomized design, with significant differences obtained for most of the variables studied, except for ether extract, calcium, iron and oxalates. From the nutritional point of view, the first harvest was the most acceptable due to the chemical composition of the plant, in particular protein (29.5%), beta-carotene (33.7 mg%), calcium (2,356.1 mg%), phosphorus (759.1 mg%) and due to its low crude fiber content, only 11.1 g%. It did not occur so from the agronomic point of view, since during this stage, very low yields of green matter (575.9 kg/ha), dry matter (66.6 kg/ha) and protein (19.7 kg/ha) were obtained. At the second harvest, besides obtaining adequate yields of green matter (6,530.4 kg/ha), dry matter (681.8 kg/ha) and protein 154.3 kg/ha), an acceptable composition in its protein content (22.7 g%), beta-carotene (24.1 mg%), calcium (2,279.8 mg%), phosphorus (740.9 mg%) and iron (52.7 mg%) was also obtained. The crude fiber content, on the other hand, was not excessively increased (14.3 g%), from which findings it was concluded that this is the best stage for harvesting, in comparison with the harvests carried out 25 and 60 days after emergence. Finally, it was observed that harvesting at 60 days gave the highest yields in green matter (24,272.8 kg/ha), dry matter (3,452.0 kg/ha) and protein (510.7 kg/ha).(ABSTRACT TRUNCATED AT 400 WORDS)

Agriculture↗
PubMed1987

[Evaluation of different levels of amaranth flour (vegetative parts), in substitution for alfalfa flour for growing rabbits].

The vegetative part of the amaranth plant could be a useful resource for animal feeding due to its chemical characteristics and to the high yield obtained when harvested between 45 and 60 days after planting. Six diets were evaluated in order to determine the feed efficiency of amaranth (Amaranthus hypochondriacus) for growing rabbits. The diets contained dehydrated amaranth leaves and stalks in levels of 0, 15, 30, 45 and 60%, to replace equal amounts of alfalfa leaf meal. An additional diet containing 60% of steam-treated leaves and stalks of amaranth, for five minutes, prior to dehydration and milling, was also tested. The amaranth leaf meal contained 17.8% protein and 12.4% crude fiber as compared with the alfalfa leaf meal which contained 22.0% protein and 23.3% crude fiber. In terms of weight gain, feed intake, feed efficiency, carcass weight and serum proteins, the results indicated that amaranth leaf meal can efficiently replace alfalfa leaf meal up to 15% of the total weight of the diet. Higher levels, however, caused growth retardation and a pathological picture characterized by interstitial nephrosis and edema, more easily observed at a 60% level in the diet. Results also revealed that a steam treatment improves the nutritive quality of the amaranth meal.

Animal Feed↗
PubMed1986

Respiratory systems of the Bacillus cereus mother cell and forespore.

The respiratory systems of the mother cells and forespores of Bacillus cereus were compared throughout the maturation stages (III to VI) of sporulation. The results indicated that both cell compartments contain the same assortment of oxidoreductases and cytochromes. However membrane fractions from young forespores were clearly distinct from those of the mother cell, i.e., lower content of cytochrome aa3, lower cytochrome c oxidase activity, higher concentration of cytochrome o, and a lower sensitivity of the respiration to the inhibiting effect of cyanide. This suggests that the cyanide-resistant pathway contributes more importantly to forespore respiratory activity than to activity in the mother cell compartment. During the maturation stages, the forespore NADH oxidase activity declined faster than in the mother cells. Other activities studied decreased steadily in both cell compartments. These findings together with the analysis of the kinetics of NADH-dependent reduction of cytochromes in the mature spore membranes indicated an impairment of electron flow between NADH dehydrogenase and cytochrome b. This impairment could be overcome by the addition of menadione.

Bacillus cereus↗
PubMed1986

[Lupoid syndrome in "BCG-itis." Report of a case].

It is presented the first case of lupoid syndrome of "BCG-itis" found in El Salvador. Its clinic-pathological study is conclusive for such dermatological entity. The complications of vaccination with BCG are rare. It must be treated as an active tuberculosis, but with a greater control of the patient.

Adult↗
PubMed1984

Pertussis toxin blocks the action of morphine, norepinephrine and clonidine on isolated guinea-pig ileum.

Administration of pertussis toxin (60 micrograms/kg i.p.) to guinea-pigs blocked the ability of morphine, norepinephrine and clonidine to inhibit electrically stimulated contractions in the isolated ileum. The toxin reached its maximum effect 6 days after its administration. The effect of the toxin was reversible; a slow but full recovery of the response to morphine was observed in ilea from guinea-pigs treated with toxin 18 days before the experiment. It is suggested, based on the known action of pertussis toxin, that inhibition of adenylate cyclase through Ni (guanine-nucleotide regulatory protein) is involved in the acute action of morphine, norepinephrine and clonidine in the motoneurons of the myenteric plexus of the ileum.

Adenylate Cyclase Toxin↗
PubMed1984

The effect of different kinds of refeeding on islet glucose phosphorylating activities.

The aim of the present work has been to study the regulating effect of different kinds of diet on the activities of enzymes that phosphorylates glucose into glucose 6 phosphate in the islets of Langerhans. The metabolism of glucose in the B cell is controlled by two different enzymes, hexokinase and glucokinase, whose activities are lowered during fasting; this coincides with lowered levels of blood glucose and blood insulin and with a blocking of the insulin-secretory response toward glucose. Refeeding with a high-carbohydrate diet restores glucokinase activity in islet extracts, blood insulin, and blood glucose. By contrast, refeeding with a low-carbohydrate diet restores hexokinase activity in islet extracts, restores poorly blood insulin, and is unable to unblock the insulin secretory response toward glucose. These results support the important role that glucokinase plays in the regulation of glycolytic flux and on insulin secretion in the B cell. Hexokinase could play a role in the regulation of the glycolytic flux when the B cell responds to other secretagogues.

Animals↗
PubMed1984

Glucose phosphorylating activities in the islets of Langerhans of the rat. Effect of fasting.

In the present study, the characterization of glucose phosphorylating activities in islet extracts and the effect of fasting on these activities have been studied. 4 mM glucose 6-phosphate strongly inhibits hexokinase activity, while glucokinase increased its activity. N-acetyl-glucosamine inhibits hexokinase activity (40% inhibition), while glucokinase increased its activity (19% increment). Both phosphorylating activities reaches a maximum when the Mg/ATP ratio is 1; increments in Mg/ATP ratio inhibits glucokinase activity while hexokinase activity is less dependent of Mg/ATP ratio. Fasting induces a progressive decrease of both phosphorylating activities in islet extracts. After 48 h fasting both activities are decreased 50%. After 96 h fasting, glucokinase activity disappeared completely, while hexokinase was 80% reduced. Our data suggest that hexokinase is less affected by fasting than glucokinase. In addition, other authors have reported that other glycolytic enzymes are little altered by fasting. Hence the fasting-induced-adaptation of glucokinase could account for the reduced rate of glycolysis and subsequently reduced insulin secretory response towards glucose.

Adenosine Triphosphate↗
PubMed1984

Effect of 2-bromostearate on glucose-phosphorylating activities and the dynamics of insulin secretion in islets of Langerhans during fasting.

Glucose-phosphorylating activity and insulin secretion were measured in homogenates of isolated rat islets and of perfused rat pancreas, respectively. Fasting for 96 h produced a significant decrease of both low-and high-Km glucose-phosphorylating activities and blocked the insulin secretory response to glucose. In the presence of glucose, 0.25 mM 2-bromostearate, a known inhibitor of fatty acid oxidation, partially restored the insulin response to glucose that was lost during fasting. This effect paralleled the restoration of glucose-phosphorylation activities (primarily the high-Km component) seen when islets isolated from 96-h-fasted rats were preincubated with 0.25 mM 2-bromostearate. It is concluded that fasting-induced adaptations of glucose-phosphorylating enzymes could account, at least in part, for the reduced insulin secretory response to glucose. 2-Bromostearate, an inhibitor of fatty acid oxidation, is able to restore both insulin secretory response and glucose-phosphorylating activities, suggesting possible interrelations among the correlated impairment in insulin secretion, islet glucose-phosphorylating activity, islet glucose metabolism, and the oxidation of fatty acids in the B-cell during fasting.

Animals↗