A Study on Intraspecific Resource Partitioning in the Stingless bee Scaptotrigona mexicana Guérin (Apidae, Meliponini) Using Behavioral and Molecular Techniques.

As a general rule, within an ecological guild, there is one species that is dominant and is commonly the most abundant. The aim of this work was to investigate if such pattern occurs intraspecifically, among colonies of the stingless bee Scaptotrigona mexicana Guérin. Through behavioral and molecular techniques, we found preliminary evidence that apparently colonies of this species do not monopolize resources, instead they seem to share food; however, some colonies had more foragers in a food patch or in a feeder, so some type of exclusion could be at work, though we could not determine the final output of such interaction, i.e., if underrepresented colonies were eventually excluded, developed slower or were overrepresented in other food patches. Our results give evidence that resource partitioning within this species occurs peacefully; however, further studies are necessary to determine if threatening behavior or aggressions appear when resources are scarce and competition becomes harsher.

Green tea reduces LDL oxidability and improves vascular function.

OBJECTIVE: Several different epidemiological studies have examined the association between the consumption of tea and coronary heart disease. Some, though not all, support the view that tea or flavonoids reduce the risk of cardiovascular heart disease. The aim of this study was to determine the short-to medium-term effect of a green tea extract on vascular function and lipid peroxidation as compared with placebo. METHODS: The study was undertaken with 14 healthy women, none of whom were receiving any medical treatment. Measurements were made of antibodies and immune complexes by ELISA, endothelial dependent vascular function by Doppler ultrasound, and the concentration of oxidized LDL by TBARS. RESULTS: The mean diameter of the brachial artery following the post-compression hyperaemia phase rose significantly (p < 0.0001) after treatment with green tea extract. Flow-mediated brachial artery vasodilation ranged from 5.68% for the placebo phase to 11.98% after the green tea extract (p = 0.02). The consumption of green tea extract was associated with a significant 37.4% reduction in the concentration of oxidized LDL (TBARS) (p = 0.017). The levels of anti-oxidized LDL IgM antibodies fell significantly after treatment (p = 0.002). CONCLUSION: This study found that consumption of green tea extract by women for five weeks produced modifications in vascular function and an important decrease in serum oxidizability.

Long term outcome of patients with postinfarction left ventricular pseudoaneurysm.

BACKGROUND: It is debatable whether surgical repair is routinely indicated in asymptomatic patients with left ventricular pseudoaneurysms. OBJECTIVE: To evaluate the long term outcome of patients with pseudoaneurysm after myocardial infarction, focusing on those treated conservatively. METHODS: 10 patients with postinfarction left ventricular pseudoaneurysm were followed up over a mean (SD) period of 3.8 (5.2) years. RESULTS: In those treated conservatively (n = 9), cumulative survival was 88.9 (10.5)% and 74.1 (16.1)% at one and four years, respectively. The probability of being free of cardiac death was 88.9 (10.5)% at both one and four years. No patient had complete fatal heart rupture during follow up. Three patients suffered ischaemic stroke (at 1, 11, and 62 months). The cumulative incidence of ischaemic stroke was 10% at one year and 32.5% at four years. CONCLUSIONS: Long term outcome of patients with postinfarction left ventricular pseudoaneurysm is relatively benign, with a very low risk (none in this series) of fatal rupture. Taking into consideration the relatively high risk of stroke, chronic anticoagulant treatment could be considered.

Primary esophageal lymphoepithelioma.

Lymphoepitheliomas are extremely rare outside the nasopharynx. Extranasopharyngeal lymphoepithellomas may be located in the stomach or digestive tract, and only one single case of esophageal location has been found in our review. In many cases the tumor is related to Epstein-Barr virus infection. We report a case of undifferentiated carcinoma of the distal third of the esophagus in a 79 year-old man. Pathological examination of the esophagus revealed an undifferentiated carcinoma with lymphold stroma (lymphoepithelioma). In situ hybridization of the neoplastic cells was negative for Epstein-Barr virus. To our knowledge, the present case is the first documented esophageal lymphoepithelioma in Western countries.

[Postoperative gallbladder and systemic candidiasis]. / Candidiasis vesicular y sistémica post-operatoria.

Gangrenous cholecystitis occurred in an immunodepressed patient with generalized neoplasia. Evolution was rapid and severe. Emergency cholecystectomy and systemic treatment with Anphotherycin were life-saving.

Implication of lysine residues in the loss of 6-phosphogluconate dehydrogenase activity in aging human erythrocytes.

The activity of 6-phosphogluconate dehydrogenase (6-PGDH) decreases in aged human erythrocyte populations. The aged enzyme has 11 lysine residues less than the young enzyme, when they are measured with 2,4,6-trinitro-benzenesulfonic acid (TNBS). Treatment of young enzyme with ascorbate for 15 min produces the loss of 8 lysine residues and the diminution of enzymatic activity. These results suggest that there is a modification of lysine residue in human erythrocytes during senescence, probably caused by oxidation. This modification of lysine residue could imply the loss of enzymatic activity. This result is similar to that found in rat liver 6-PGDH during aging, described previously (Gordillo et al., J. Biol. Chem. 264 (1989) 17014-17019).

Involvement of diminution of glutathione, produced by deficiency of methionine in the diet, in the elevation of malic enzyme level in rat liver.

Rats fed on a low protein diet show an increase in the specific activity of malic enzyme and a concomitant decrease of glutathione concentration. We have studied the effect on malic enzyme activity of supplementing of low protein diet with essential amino acids. Only when methionine was excluded from the diet did the specific activity of malic enzyme increase to the same extent as found in rats fed with low protein diet. Immunoprecipitation of malic enzyme indicated that specific activity changes are the result of changes in the amounts of enzyme. Under all dietary conditions studied, the increase in malic enzyme activity is associated with a decrease in the concentration of GSH. To evaluate the possible causative role of GSH in malic enzyme induction, the specific activity of malic enzyme was measured in rats treated with BSO, an inhibitor of GSH biosynthesis. The results show that in BSO-treated rats the decrease of GSH levels is also accompanied by an increase in the activity of malic enzyme.

Age-dependent changes in the activity and isoenzymatic pattern of the phosphofructokinase in different areas of the central nervous systems.

Regional activity of phosphofructokinase enzyme and the amount of the isoenzyme C in 7 areas of young, adult and aged rats brain have been studied. The phosphofructokinase activity in substantia nigra decreased in adult and aged rats, but the maximum decrease was found in the septum of aged rats. There is a regional distribution of the isoenzyme C in the different areas studied. There was a general decrease in the amount of this isoenzyme in the areas studied with the exception of the hippocampus and the amygdala. The highest decrease was found in the septal area and in the diagonal band of Broca. These results are discussed in relation to the aging in different regions.

Relationship between enzymatic activity loss and post-translational protein modification in aging.

During aging, there is a decrease in the activity of many enzymes. The mechanism causing the loss of activity is still not well understood in most cases. We have studied the decrease in the activities of the malic, 6-phosphogluconate dehydrogenase and superoxide dismutase enzymes. The old malic enzyme is about 36% less active than the young enzyme and the old 6-phosphogluconic dehydrogenase enzyme is about 26% less active than the young enzyme. In this paper, some chemical properties of these enzymes are studied. Diethyl pyrocarbonate measurements indicate that the old malic enzyme has 1 histidine residue less than the young malic enzyme. Moreover, the treatment of the young malic enzyme with ascorbate for 15 min produces the loss of 36% of enzymatic activity and the loss of 1.2 histidine residues. 2,4,6-trinitrobenzenesulfonic acid measurements indicate that the old 6-phosphogluconate dehydrogenase enzyme has 11 lysine residues less than the young 6-phosphogluconate dehydrogenase enzyme. The proteolysis with trypsin produces more peptides in the young 6-phosphogluconate dehydrogenase enzyme than in the old one. However, similar numbers of peptides were produced when endoproteinase Arg-C was used in both enzymes, young and old 6-phosphogluconate dehydrogenase. Moreover, the treatment of young 6-phosphogluconate dehydrogenase enzyme with ascorbate for 15 min produces the loss of 8 lysine residues. These results suggest that during aging the modification of histidine residue could be involved in the loss of malic enzyme activity, and the modification of lysine residues could be involved in the loss of 6-phosphogluconate dehydrogenase activity. These results could also suggest that the modification of histidine and lysine residues during aging could be produced by oxidation. This could be a general process in aging, with an increase in the oxidation of many proteins. The relevance of this process in the aging effects must be related to the kind of proteins that are susceptible of oxidation and that this oxidation affects their enzymatic or biological function. We have also studied other enzymes one of which is the superoxide dismutase enzyme involved in the protection against oxidative damage. Our results are similar to those described for malic enzyme. In the latter case, the failure to measure one of the histidines in the Cu/Zn SOD is due to a chemical modification, probably caused by oxidation of the residue.

[Intra-articular treatment of osteoarthrosis of the knee with betamethasone dipropionate and disodium phosphate. Non-controlled, open 5 years' experience]. / Tratamiento intraarticular de la osteoartrosis de rodillas con dipropionato y fosfato disódico de betametasona. Experiencia en cinco años, abierta, no controlada.

We reviewed the result of treatment of knee osteoarthritis with intraarticular injection of betamethasone derivatives in 100 patients over a 5 year period. Knee involvement was bilateral in 34 of these patients. 1 ml of a mixture of betamethasone dipropionate and betamethasone phosphate was injected intraarticularly in each patient and repeated if needed at 3 week intervals. A total of 496 injections (mean 3.7 per knee, minimum 1 and maximum 18) were performed. Clinical and radiological evaluation before and midway through therapy revealed no side effects. The clinical response in terms of pain, mobility and functional capacity was good. We conclude that the therapy described results in good clinical and functional results over long periods of time in patients with knee osteoarthritis.

Implication of lysine residues in the loss of enzymatic activity in rat liver 6-phosphogluconate dehydrogenase found in aging.

During aging, there is a decrease in the activity of the 6-phosphogluconate dehydrogenase enzyme in rat liver. The "old" 6-phosphogluconate dehydrogenase enzyme is about 26% less active than the "young" enzyme. In this paper, some biochemical and chemical properties of this enzyme are studied. 2,4,6-Trinitro-benzenesulfonic acid measurements indicate that the old enzyme has 11 lysine residues less than the young enzyme. The proteolysis with trypsin produces more peptides in the young enzyme than in the old one. However, similar numbers of peptides were produced when endoproteinase Arg-C was used on both enzymes. Moreover, the treatment of the young enzyme with ascorbate for 15 min produces the loss of 8 lysine residues. These results suggest that during aging there is a modification of the lysine residue, and this could be involved in the loss of its enzymatic activity.

Possible involvement of histidine residues in the loss of enzymatic activity of rat liver malic enzyme during aging.

During aging there is a decrease in activity of the malic enzyme in rat liver. The "old" malic enzyme is about 36% less active than the "young" enzyme. Some properties and modifications of amino acid residues are studied here (--SH, arginine, methionine, histidine, lysine) to try and check on the existence of any relationship between them and the loss of enzymatic activity during aging. Diethyl pyrocarbonate measurements indicate that the old enzyme has 1 histidine residue less than the young enzyme. Moreover, the treatment of the young enzyme with ascorbate for 15 min produces the loss of 36% of the enzymatic activity and the loss of 1.2 histidine residues. These results suggest that during aging the modification of the histidine residue could be involved in the loss of its enzymatic activity.