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O Fuentes

Publications and source records attributed to O Fuentes.

At least 19 recordsLinked to original sources
PubMed1998

Intestinal leiomyosarcoma as the cause of severe hemoperitoneum.

Leiomyosarcomas represent 10-20% of malignant tumors in the small bowel and 1% of those located in the large bowel. These tumors have aspecific symptoms depending on their size, location and histology. Intestinal leiomyosarcomas may be the cause of numerous types of surgical emergency. We report 2 cases of intestinal leiomyosarcoma in the jejunum and transverse colon. Both were diagnosed during an emergency exploratory celiotomy. The clinical features on admission were similar to those of acute abdomen. The main cause of surgical emergency was an extremely rare complication of gastrointestinal leiomyosarcoma: a severe hemoperitoneum. We briefly describe the surgical emergencies caused by intestinal leiomyosarcomas as well as the surgical methods employed in these cases.

Colonic Neoplasms↗
PubMed1998

[The effect of insecticide resistance on the demographic parameters of 3 strains of Culex quinquefasciatus (Diptera: Culicidae) under laboratory conditions].

The life tables of 3 strains of Culex quinquefasciatus were studied under laboratory conditions: Slab, susceptible to reference; Old Havana, treated with cypermethrin until its fourth generation; and Cotorro, from the field. It was found that the different levels of resistance to organophosphate insecticides and pyrethroids present in the Cotorro and Old Havana strains did not influence either on the duration of the period of development of the immature stages or in the sexual proportion of the emerged adults, but they had a favorable and directly proportional effect on the survival and longevity of the adults. However, they exerted a negative and inversely proportional influence on the reproduction and population growth of these strains. Useful data for the use and management of insecticides within the strategies of control of Culex quinquefasciatus, an important vector of lymphatic filariasis, are provided.

Animals↗
PubMed1998

[The incidence of Culicidae in an urban area of Ciudad de La Habana during 1995].

In the present paper it is made an analysis of the incidence of culicides in the municipality of Marianao, Havana City, during 1995, after following the requirements of the National Program for the Eradication of Aedes aegypti. 6 species of mosquitoes were found in the municipality, with a predominance of the Culex quinquefasciatus and Aedes mediovittatus species. 4 focuses of Aedes aegypti were detected during this period. It was found that the groups of deposits preferred by the culicides for their breeding in this municipality were other deposits, low tanks, artificial deposits and larva traps. The People's Councils 4 and 5 (Libertad and Pogolotti) had the highest number of focuses (967 and 1,240, respectively, and therefore, they need more attention. It is analyzed the influence of the deficiencies of the public services, such as the collection of solid, wastes (garbage) and the existence of leakages and sewing overflows, on the proliferation of mosquitoes in the municipality.

Animals↗
PubMed1998

[The effect of 2 diets on the biological aspects of Blattella germanica (Dictyoptera: Blattellidae) under laboratory conditions].

It was conducted a study of 2 colonies of Blattella germanica (Dictyoptera: Blattellidae) kept since 1994 in the laboratory at 29 +/- 1 degrees C, 70-75% of relative humidity and with different foods: one on a diet without proteins, consisting in portions of potatoes (Solanum tuberosum, L.), ripe banana (Musa paradisiaca, L.) and a sugary solution 10%, and the other with a protein content of 20.45% composed of pulverized and dry laboratory food for rats and a source of water. 6 nymphal stages were found with both types of food. There were determined the times of interchanges and the time of nymphal development, which were much shorter among the nymphs fed with proteins. The longevity of each sex showed no significant differences in connection with the type of food used. The times of appearance and eclosion of the oothecae of each oothecal cycle were determined with both foods. It was found that the females deposited up to 5 oothecae during their lives with the 2 types of diet. The average of nymphs per ootheca among the females fed with proteins was much greater (t = 5.33; p < 0.001). The results of this study show that when the food for B. germanica contains proteins, its nymphal development is faster and its reproductive capacity increases, which means that protein is a necessary nutrient for the diet of this species.

Analysis of Variance↗
PubMed1997

Time-dependent changes of serum gastrin and gastrin receptors in the rat oxyntic mucosa after proximal gastric vagotomy.

Proximal gastric vagotomy (PGV) is a first-choice approach for the surgical treatment of duodenal peptic ulcer. However, a high percentage of recidivism takes place after this surgical strategy. To study the possible involvement of gastrin in ulcer recidivism, serum gastrin levels and gastrin receptors in gastric mucosa were determined at several times after PGV in rats. Gastrin concentration was determined using a commercial radioimmunoassay kit and gastrin receptors were analyzed in oxyntic mucosa membrane preparations using 125I-labeled 15-Leu-gastrin-17 as label. Our results show a significant, time-dependent increase in serum gastrin concentration, reaching highest values at 12 weeks after PGV. Similarly, a significant increase in the number of gastrin receptors (Bmax) and in the dissociation constant (Kd) occurred from 1 to 12 weeks post-PGV. Since gastrin exerts a positive feedback effect on its receptors, the PGV-dependent increase in serum gastrin concentration explains the up-regulation of the gastrin receptors in the rat oxyntic mucosa. Furthermore, an increase in the number of gastrin receptors after vagotomy may be at least partially responsible for the recidivism in duodenal peptic ulcers after this surgical approach.

Animals↗
PubMed1997

Diabetes and insulin-induced stimulation of L-arginine transport and nitric oxide synthesis in rabbit isolated gastric glands.

1. The properties of L-arginine transport have been characterized and correlated with cGMP production (index of nitric oxide (NO)) in whole gastric glands isolated from non-diabetic and alloxan-diabetic rabbits. 2. In non-diabetic and diabetic glands, transport of L-arginine was stereoselective, Na+ and pH independent and inhibited by other cationic amino acids. L-Arginine transport was slightly inhibited by L-leucine and L-phenylalanine, but unaffected by other neutral amino acids. 3. Diabetes enhanced the Vmax for saturable L-arginine transport from 10.7 +/- 1.0 to 17.7 +/- 0.5 pmol (mg protein)-1 s-1, with negligible changes in K(m). 4. Accumulation of the membrane potential-sensitive probe tetra[3H]phenylphosphonium (TPP+) was increased 2-fold in diabetic compared with non-diabetic gastric glands, suggesting a membrane hyperpolarization. 5. Basal intracellular cGMP levels were elevated 2-fold in diabetic gastric glands, and in non-diabetic glands histamine, vasoactive intestinal peptide, and bradykinin increased cGMP levels. The NO synthase inhibitor NG-nitro-L-arginine methyl ester (100 microM) abolished basal cGMP accumulation. 6. Addition of extracellular L-arginine induced a concentration-dependent increase in cGMP levels in gastric glands isolated from non-diabetic rabbits, but had no effect on elevated cGMP levels in diabetic glands. 7. Insulin induced a rapid (5 min) concentration-dependent increase in cGMP levels in non-diabetic gastric glands, but reduced elevated cGMP levels in diabetic gastric glands. 8. The present study has identified a specific transport system for L-arginine in gastric glands which resembles the classical system y+. Our findings also provide the first direct evidence that diabetes increases the basal activity of system y+ and NO synthase in gastric glands. The differential modulation of L-arginine transport by insulin and L-arginine identified in non-diabetic and diabetic glands, may be of importance in protecting the gastric mucosa from injuries associated with diabetes.

Animals↗
PubMed1996

[Biological aspects of Blatella germanica (Dictyoptera: Blattellidae) in laboratory conditions].

In a study of Blatella germanica (L) 1767 (Dictyoptera: Blattellidae) carried out in laboratory conditions, 6 nymphal stages were found in a period of 114.71 days, at 29 +/- 1 degrees C and 80-90% of relative humidity. Times of appearence and eclosion of every ovipositted ootheca, as well as the offspring average of each one, were determined. Females ovipositted up to 5 oothecas during their life. The maximum average of eggs found per ootheca was 29.22. The average longevity of males was lower that that of females (77.23 and 98.40 days, respectively) (t = 2.21; p < 0.05).

Animals↗
PubMed1995

[Can a selenium deficiency affect the pathogenesis of cholestasis in pregnancy?].

UNLABELLED: In search of an environmental factor which modulates the expressivity of cholestasis of pregnancy and explains the seasonal and annual variations observed in Finland and Chile, the authors measured selenium (Se) concentration in the plasma and erythrocytes by atomic absorption spectrophotometry and the activity of the glutation peroxidase enzyme dependent on Se (GSH-Px) by a spectrophotometric method in 10 patients with cholestasis of pregnancy, 22 normal pregnant women, 43 non pregnant women and in 15 men, all of whom had normal weight/height, and similar ages, ethnic and geographic origin. Blood samples were obtained weekly from the pregnant women during the third trimester and 24-72 hours postpartum. RESULTS: In non pregnant women and in men plasma Se was 0.83 +/- 0.02 mumol/l (range 0.6-1.2) and the GSH-Px activity was 306 +/- 5 U/L (range 203-459). Both parameters were correlated and were similar to those of other populations whose ingestion of Se is low (Finland, New Zealand, and certain regions of China). In normal pregnant women studied between weeks 20 and 32, the plasma Se and GSH-Px activity were lower than in non pregnant women (0.71 +/- 0.02 mumol/l and 260 +/- 5 U/l, respectively) with both progressively decreasing at the end of pregnancy and rapidly recovering post partum. The erythrocytic GSH-Px activity was similar in normal pregnant women than in non pregnant women (27.7 +/- 0.8 versus 28.1 +/- 0.6 U/g Hb). In patients with cholestasis of pregnancy, plasma and erythrocytic Se and GSH-Px activity were lower than in normal pregnant women (p < 0.05 in similar stages of pregnancy).(ABSTRACT TRUNCATED AT 250 WORDS)

Chile↗
PubMed1994

Calcium-dependent block of ryanodine receptor channel of swine skeletal muscle by direct binding of calmodulin.

The interaction of the Ca2+ binding protein calmodulin (CaM) with the ryanodine receptor of the sarcoplasmic reticulum (SR) of pig skeletal muscle was investigated by [3H]-ryanodine binding, planar bilayer recordings, and rapid filtration of 45Ca(2+)-loaded SR. Inhibition of [3H]-ryanodine binding by CAM was phosphorylation-independent, had an IC50 of approximately 0.1 microM and was optimal at 10 microM Ca(2+). CaM also inhibited [3H]-ryanodine binding to CHAPS-solubilized and purified ryanodine receptors, suggesting a direct CaM-ryanodine receptor interaction. In single channel recordings, CaM blocked Ca2+ release channels in a Ca(2+)-dependent manner by decreasing the number of open events per unit time without affecting the mean open time or unitary channel conductance. Rapid filtration of 45Ca2+ passively loaded into SR vesicles showed that CaM blocked Ca2+ release within milliseconds of exposure of SR to a Ca2+ release medium containing 10 microM CaM. In controls, an increase in extravesicular Ca2+ from 7 nM to 10 microM resulted in a release of 47 +/- 10% of the 45Ca2+ in 20 ms. CaM reduced the release to 23 +/- 12% in the same period. These results are compatible with a direct mechanism of Ca2+ release channel blockade by CaM and suggest that CaM could play a significant role in the inactivation of SR Ca2+ release during excitation-contraction coupling.

Animals↗
PubMed1993

Starvation effect on rat kidney peroxisomal and microsomal fatty acid oxidation. A comparative study between liver and kidney.

Microsomal lauric acid 12-hydroxy lauric acid (omega)-hydroxylation and fatty acid peroxisomal beta-oxidation were studied in kidney tissue from starved rats. Starvation increased the microsomal omega-hydroxylation and peroxisomal beta-oxidation of fatty acids with a high correlation between both processes. Earlier, we reported similar results in liver. Our results support the hypothesis that the role of microsomal fatty acids omega-hydroxylation is the generation of substrate for peroxisomal beta-oxidation, with the final purpose of contributing to a catabolic or gluconeogenic pathway from fatty acids.

Animals↗
PubMed1992

Modulation of rat liver peroxisomal and microsomal fatty acid oxidation by starvation.

In this work the microsomal lauric acid omega-hydroxylation, fatty acid peroxisomal beta-oxidation, and the levels of cytochrome P-450 IVA1 were studied in liver tissue from starved rats. Starvation increased the peroxisomal beta-oxidation and the microsomal hydroxylation of fatty acids. The correlation between these activities would support the proposal that both processes are linked, contributing in part to catabolism of fatty acids in liver of starved rats.

Animals↗
PubMed1992

Presence of Aedes (Gymnometopa) mediovittatus in Cuba: a new factor to be considered in the national campaign to eradicate dengue.

To assess the presence of the potential dengue vector Aedes mediovittatus relative to other mosquito species, data were examined from 44,199 larvitraps operating between January 1984 and December 1987 in the town of Mariel, Cuba. Of 1,068 larvitraps containing mosquitoes, 626 (58.6%) were positive for Ae. mediovittatus. Its relative presence increased each year except 1986, going from 37.9% of the positive traps in 1984 to 70.2% in 1987. More larvitraps were positive for Ae. mediovittatus than for Culex quinquefasciatus, which typically dominated breeding sites at the end of the intensive phase of the national campaign against Ae. aegypti in the early 1980s. The results appear to reflect Ae. mediovittatus' gradual infiltration into areas covered by the campaign, a factor that may need to be considered in efforts to control dengue in the Americas.

Aedes↗
PubMed1991

Activation of the ryanodine receptor Ca2+ release channel of sarcoplasmic reticulum by a novel scorpion venom.

We identified a peptide fraction from the venom of the scorpion Buthotus hottentota that stimulated binding of [3H]ryanodine to ryanodine receptors of skeletal and cardiac sarcoplasmic reticulum and brain microsomes in a highly specific manner. Activity was concentrated in a peptide fraction of Mr 5,000-8,000. Assuming a single active peptide in this fraction, we estimated a dissociation constant of 20-30 nM for the interaction of the peptide with the ryanodine receptor. The whole venom and the purified fraction activated skeletal ryanodine receptor Ca2+ release channels incorporated into planar lipid bilayers. The venom produced a 10-fold increase in the mean open time and induced the appearance of a long lasting subconductance state not seen in controls. Changes were reversible and could be induced by the partially purified venom fraction. This novel scorpion venom should be helpful in establishing the role of ryanodine receptors in the initiation of intracellular Ca2+ release in striated muscle and in nonmuscle cells containing functional ryanodine receptors such as neurons and secretory cells.

Animals↗
PubMed1969

[Not Available].

Explore the source record for details and available documents.

Argentina↗
PubMedDate not supplied

[Episiotomy: some considerations].

3,731 births occurred in the second semester of 1987 (from June 1 to December 31) are reviewed. Patients with eutocic and instrumental deliveries who underwent episiotomy to aid childbirth are selected. Those who had complications in one way or another are selected for their study by different variables developed for the purpose.

Cuba↗