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Biomedical subjects

J A Núñez

Publications and source records attributed to J A Núñez.

11 recordsLinked to original sources
PubMed1997

Oxygen consumption in the foraging honeybee depends on the reward rate at the food source.

Oxygen consumption of the honeybee Apis mellifera ligustica was measured as a function of the flow rate supply of sucrose solution at an automatic feeder located inside a respirometric chamber. Trained bees freely entered the respirometric chamber and collected the sucrose solution supplied. The mean value of the O2 consumption rate per visit increased with the sucrose flow rate, and for a given flow rate, with increasing locomotor activity. However, when no locomotor activity was displayed, O2 consumption also increased with increasing nectar flow rate. Crop load attained at the end of the visit showed a positive relationship with the nectar flow rate; however, for a given flow rate, O2 consumption showed either no correlation or a negative one with the final crop load attained. It is concluded that the energy expenditure of the foraging bee is controlled by a motivational drive whose intensity depends on the reward rate at the food source.

Animals↗
PubMed1995

Baker's yeast, an attractant for baiting traps for Chagas' disease vectors.

We tested the attraction of volatile compounds, produced by the aerobic growth of Saccharomyces cerevisiae on saccharose for Triatoma infestans. For these tests, we exploited the behavioural characteristic of these haematophagous insects of dropping when searching for food. In olfactometer assays, yeast cultures activated and attracted bugs as effectively as a mouse. The attraction of the cultures was significantly reduced when the carbon dioxide released was partially eliminated using potassium hydroxide. Yeast cultures were also tested as lures in a novel trap device. A baited device for trapping Chagas' disease vectors using the behavioural peculiarities of T. infestans and this simple attractant is described.

Animals↗
PubMed1992

Metabolic rate during foraging in the honeybee.

The metabolic rate of free-flying honeybees, Apis mellifera ligustica, was determined by means of a novel respirometric device that allowed measurement of CO2 produced by bees foraging under controlled reward at an artificial food source. Metabolic rate increased with reward (sugar flow rate) at the food source. In addition, there was no clear-cut dependence of metabolic rate on load carried during the visit, neither as crop load nor as supplementary weights attached to the thorax. The hypothesis that metabolic rate, as well as foraging and recruiting activities, depend on the motivational state of the foraging bee determined by the reward at the food source is discussed.

Animals↗
PubMedDate not supplied

Local conjunctival immunotherapy: the effect of dermatophagoides pteronyssinus local conjunctival immunotherapy on conjunctival provocation test in patients with allergic conjunctivitis.

BACKGROUND: We evaluated the effect of local conjunctival immunotherapy (LCIT) with standardized dermatophagoides pteronyssinus (Dp) extracts on antigen-specific conjunctival provocation test (CPT) in patients with allergic conjunctivitis in a double blind, placebo-controlled study. We use the CPT because in our experience is the more objective parameter to evaluate the sensitivity to allergens in this patients. METHODS: The patients were selected on the basis of symptoms, positive prick test, positive CPT and elevated serum and tears total and specific IgE. The CPT was assessed with increased dilution of Dp extracts instilled into the lower fornix. Conjunctival hyperemia, tearing, itching, burning and swelling of eyelids were scored according a 4-point rating scale. Patients were randomly assigned to 2 groups of 12. The first group was treated with Dp extracts and the second group with placebo during 6 months. A drop of diluted antigen was instilled in both eyes daily, in 2-fold increased concentrations, the first 10 AU/ml. The maintenance dose was 1,000 AU/ml or the maximal dose which did not provoke symptoms. The symptoms were controlled with oral and/or local antihistamines. We evaluated the CPT before and after the treatment. The patients did not receive antihistamines during the 15 previous days to carrying-out the CPT. RESULTS: Ten of the twelve patients of the active group complete the treatment. One of the patients dropped out of the study because experienced local reaction with a dose of 1,000 AU/ml and refused to continue with the treatment. Other patient was disqualified for failure to comply with the protocol. One patient, which experienced itching and tearing with a dose of 1,000 AU/ml, tolerate 100 AU/ml. We continue with this dose until the end of treatment. The remaining patients tolerate 1,000 AU/ml as maintenance dose. A significant difference was observed in the score of CPT between LCIT treated patients and placebo group after 6 month of LCIT. CONCLUSIONS: We propose LCIT as a useful alternative to traditional subcutaneous immunotherapy in patients with allergic conjunctivitis.

Adolescent↗