Parasitism by an invasive nest fly reduces future reproduction in Galápagos mockingbirds.

Organisms allocate limited resources to competing activities such as reproduction, growth, and defense against parasites and predators. The introduction of a novel parasite may create new life history trade-offs. As hosts increase their investment in self-maintenance or defense, the cost of parasitism may carry over to other aspects of host biology. Here, in an experimental field study, we document delayed effects of an introduced nest parasite, Philornis downsi, on reproduction of Galápagos mockingbirds (Mimus parvulus). Parasitism of first nests reduced both the number and size of chicks that parents hatched when they re-nested several weeks later. The delayed effect of P. downsi on future reproduction may have been mediated by behavioral shifts by the parents to avoid or resist parasitism. Our results demonstrate that effects of parasitism can persist even after immediate exposure ends. We draw attention to the potential implications that introduced parasites have for host reproductive strategies.

Annual environmental variation influences host tolerance to parasites.

When confronted with a parasite or pathogen, hosts can defend themselves by resisting or tolerating the attack. While resistance can be diminished when resources are limited, it is unclear how robust tolerance is to changes in environmental conditions. Here, we investigate the sensitivity of tolerance in a single host population living in a highly variable environment. We manipulated the abundance of an invasive parasitic fly, Philornis downsi, in nests of Galápagos mockingbirds ( Mimus parvulus) over four field seasons and measured host fitness in response to parasitism. Mockingbird tolerance to P. downsi varied significantly among years and decreased when rainfall was limited. Video observations indicate that parental provisioning of nestlings appears key to tolerance: in drought years, mockingbirds likely do not have sufficient resources to compensate for the effects of P. downsi. These results indicate that host tolerance is a labile trait and suggest that environmental variation plays a major role in mediating the consequences of host-parasite interactions.

[Influence of breakfast on cognitive functions of children from an urban area in Valencia, Venezuela]. / Influencia del desayuno sobre la funcion cognoscitiva de escolares de una zona urbana de Valencia, Venezuela.

It's well known that physical growth and intellectual activity is influenced by nutritional status. With the purpose of evaluate the fasting effects on the cognitive functions, anthropometric state and cognitive functions (logic and school work performance), under fasting and post-breakfast condition were assessed in a group of 68 school children age 9 and 10 years, who studied in a private school (1998-1999). Logic reasoning was measured with Raven test and attention, precision, velocity and fatigue with the Lepez test. The main of the children (80%) were well-nourished and 20% had showed overweight. At breakfast condition all subjects were over 50 percentil for Raven test. Consumption of breakfast influence on logic reasoning (p < 0.001) and school work performance (p < 0.01). It is concluded that in these well nourished children, breakfast consumption improved cognitive performance.

[The factors associated with noncompliance with antimalarial treatment in Ecuadorian patients]. / Factores asociados con el incumplimiento del tratamiento antipalúdico en pacientes ecuatorianos.

A total of 249 persons living in the northwest part of Ecuador with a clinical diagnosis of malaria confirmed by thick blood films were treated with chloroquine and primaquine according to the therapeutical system in force in the National Service for Eradication of Malaria. New clinical assessment and thick blood film were applied after 4 days in P. falciparum (n = 120) cases and after 8 days in P. vivax (n = 129) cases; patients were questioned about the compliance or non-compliance with the treatment, and the reasons for their acting in either way were studied. EPI-INFO 6.04 and SPSS PC 7.0 packages served to process the information: "kind adjustment test" (bondad de ajuste) abd factorial analysis of correspondences were used. The patient who daily took his/her pills for the number of days indicated, at the established intervals and at the right time was defined as a patient complying with the drug therapy. For every 3 patients complying with treatment, there were 2 who did not; non-compliance was not significantly related to age, sex, educational level, ethnic group, urban or rural setting or level of income, but learning about seriousness of the infection did help to compliance with the therapy. The reasons for non-compliance were mainly associated with drugs (side effects/reluctancy to take drugs), with the fact of forgetting to take them and of "getting cured quickly". The profile of the patient who did not comply with treatment corresponded to male, teenager, mixed race, poor and rural setting.

[High altitude anemia: validity of definition criteria]. / Anémie en altitude: validité du critère de définition.

The effect of iron and folate supplementation on the hemoglobin response and iron status was studied in male and female equatorian medical students: 66 in Quito (2,800 m altitude) and 40 in Guayaquil (sea level). At the end of the supplementation, there was a nearly complete disappearance of biochemical evidence of iron deficiency in the two groups of students. In Quito, 30% of the men and 26% of the women increased their hemoglobin concentration by more than 1 g/dl after one month of supplementation and could be considered as true anemics, compared to 31% of the men and 29% of the women in Guayaquil. This study shows that at sea level, cut-off points defined by WHO for hemoglobin, taking as reference the impact of a supplementation trial, have a specificity of 100% but poor sensitivity (58%). For people living at high altitudes, cut-off limits adjusted for altitude seem unsuitable: the specificity is 98% but the sensitivity is 0%. Studies taking into account all the factors impacting on the hemoglobin level could be useful for defining cut-off points for high-altitude anemia better than those currently recommended.

A quantitative approach to measuring the social effects of epilepsy.

This paper describes the construction of a postal questionnaire which has been used to investigate the social affects of epilepsy on a wide range of patients. The social profile was designed following extensive patient interviews at the National Hospital for Nervous Diseases and the Chalfont Centre for Epilepsy. The initial research revealed 21 areas of concern for the individual with epilepsy, which are described. Reliability was assessed on a test/retest procedure. Validity was tested via a criterion-related study based on the behaviour of the subject. Following reliability and validity studies 14 areas were eventually selected for the final questionnaire. Instruments have been adapted for both children and adults.

Calcium supplementation reduces the risk of pregnancy-induced hypertension in an Andes population.

Previous studies have suggested that increased dietary calcium is associated with a decreased occurrence of pregnancy-induced hypertension. In this study 106 young healthy nulliparous women, residing in Quito, Ecuador, were enrolled in a double-blind, randomized, controlled clinical trial. From 24 weeks gestation until delivery they received either 2 g of elemental calcium per day or a placebo. Calcium supplementation was associated with a significantly decreased risk of pregnancy-induced hypertension, with 4.1% developing pregnancy-induced hypertension in the treatment group versus 27.9% in the placebo group. Treatment was associated with a decrease in both systolic and diastolic blood pressure over the course of pregnancy. In addition, there was a small but significant increase in serum ionized calcium levels in the calcium-supplemented group during the treatment period.

Estimación de la frecuencia de anemias nutricionales mediante un ensayo de suplementa con hierro y folatos en sujetos adultos que viven en adulto (2.800 m)

El efecto de la suplementación con una asociación de hierro y folatos sobre el estdo hematoyético y el status en hierro fue estudiado en 66 estudiantes de los dos sexos residentes en Quito (2800 m. de altitud y 40 estudiantes de la ciudad de Guayaquil (a nivel del mar). Después de un mes de suplementación, se observó la desaparición casi completa de los estigmas bioquímicos de la carencia en hierro en los estudientes de las dos ciudades. La anemia definida en función del incremento de la tasa de hemoglobina superior a 1 g/dl se observó en el 30% de los varones y en el 26% de las mujeres residentes en Quito y en el 31% y 29% respectivamente de los residentes en Guayaquil. Este estudio pone en evidencia que los límites de referencia de la hemoglobina propuestos por la O,M.S. para poblaciones asentadas a nivel del mar, tienen una buena especificidad, pero carecen de sensibilidad: 12.5% de los sujetos estudiados fueron considerados como normales siendo realmente anémicos, como lo demuestra el efecto de a suplementación. Para los sujetos que viven en altitud, los límites de referncia ajustados para la altitud correspondiente son totalmente inadecuados: todos los individuos anémicos fueron mal clasificados

Nuevo indicador de la carencia de hierro: relación hemoglobina y protoporfirina eritrocitaria

La protoporfirna es metabolismo indispensable en al síntesis del HEM, pues su presencia hace posible que el hierro en estado ferroso se incorpore en su interior mediante la acción catalítica de una enzima mitrocondrial denominada ferroquetalasa o hem sintetasa y finalmente formarse el Hem. Este hecho puede alterarse ya sea, por un estado deficitário en hierro en forma crónica o por acumulación anormal de plomo. El estudio se realiza en 199 personas de la zona rural de Sto. Domingo de los Colorados, integrado por 87 hombres (43.72%) y 112 mujeres (56.28%). Los resultados nos permiten inferir la existencia de un estado deficitario de este mineral son: niños en crecimiento rápido (lactantes, preescolares y escolares), mujeres en edad fértil y mujeres embarazadas (no consideradas en este trabajo). En este presente estudio aproximadamente el 90% de las personas pertencientes a estos grupos señalados presentan algún trastorno relacionado con el metabolismo del hierro, definido por una disminución en la concentración sanguínea de hemoglobina y un aumento en la concentración de protoporfirina eritrocitaria. Con el presente estudio pretendemos insistir en el uso de indicadores adecuados y técnicas de laboratório fáciles y fiables para determinar el estado de hierro en el organismo

Evaluation of iron-deficiency anemia by an iron supplementation trial in children living at a 2,800-m altitude.

Hemoglobin, hematocrit, serum iron and total iron-binding capacity were measured in 38 apparently healthy children living in Quito (2:800 meters in altitude). One child was considered anemic according to the WHO reference adjusted to altitude (hemoglobin less than 12.3 g/dl) and 10 had transferrin saturation of less than 15%. Thirty children received orally 2 mg/kg per day of elemental iron for 3 mth. A significant increase in hemoglobin level, serum iron-concentration, and transferrin saturation, and a significant decrease in total iron-binding capacity were observed. Nine children increased their hemoglobin concentration by greater than 1 g/100 ml and could be considered as true anemics. At the end of the supplementation, only one child had a transferrin saturation coefficient of less than 15%. WHO references for hemoglobin adjusted to altitude seem to underestimate the prevalence of anemia for populations living at high altitudes.

Iron status in Ecuadorian pregnant women living at 2,800 m altitude: relationship with infant iron status.

An evaluation of iron status was performed in 84 pregnant women at delivery (and in cord blood from their newborn) and in a control group of 32 menstruating women living in Quito (2800 m altitude). Anemia as defined according to the WHO references adjusted to altitude was observed in 46% of pregnant women. Iron deficiency was defined as the combination of a low serum ferritin level (12 micrograms/l or less) and a low transferrin saturation percentage (less than 16%). A moderate elevation in the serum ferritin concentration (between 13 and 50 micrograms/l) associated with low transferrin saturation indicated iron deficiency in an inflammatory context. Iron deficiency was present in 46% of pregnant women. Anemia was associated with iron deficiency in 59% of cases. A correlation between maternal and cord blood hemoglobin was found and some iron parameters in cord blood were related to maternal iron status, and especially to maternal iron stores assessed by serum ferritin concentration.

Interrelation of the pituitary-thyroid system at birth in man.

Samples of cord blood derived from 105 normal babies after uncomplicated deliveries were assayed for thyroxine (T4), tri-iodothyronine (T3), reverse tri-iodothyronine (rT3), thyroxine-binding globulin (TBG) and thyrotrophin (TSH). The values for T3, rT3 and TSH were log-normally distributed (geometric means 0.62 nmol/l, 3.28 nmol/l and 10.9 mu./l respectively) and those for T4 and TBG were normally distributed (means 126 nmol/l and 13.7 mg/l), The data were systematically analysed and no evidence was obtained to suggest that the concentration of TSH, which varied widely, was regulated by any of the thyroid hormones alone or in combination. There was a direct relation between the concentrations of T4 and T3 in the cord blood at birth but not between either of these and rT3. There is thus no evidence of a functional interdependence of the hypothalamic-pituitary-thyroid system in man at birth.

Reverse triiodothyronine, thyroid hormone, and thyrotrophin concentrations in placental cord blood.

Reverse triiodothyronine (rT3), triiodothyronine (T3), thyroxine (T4), thyroxine binding globulin (TBG), and thyrotrophin (TSH) were measured in sera from placental cord blood in an unselected series of 272 deliveries. In this series the concentrations of rT3 (mean 3.33 nmol/l, 95% confidence limits 1.6--7.0 nmol/l), were log normally distributed and did not overlap the adult normal range (0.11--0.44 nmol/l). There were no correlations between the cord blood concentrations of rT3, T3, T4, and TSH. The cord serum rT3 concentration was not influenced by maturity, birth-weight, or neonatal risk factors, whereas these factors did affect the concentrations of T3, T4, AND TBG. There is no arteriovenous rT3 concentration difference across the placenta, therefore the cord rT3 reflects the systemic rT3 concentration in the baby at birth. As rT3 in the neonate largely, if not entirely, derives from thyroxine from the fetal thyroid, measurement of the cord rT3 concentration may be a good immediate screening test for neonatal hypothyroidism.

The abstract and the concrete, the disciplinary and the interdisciplinary approach in the teaching of physiological sciences. / Lo abstracto y lo concreto, lo disciplinario y lo interdisciplinario en la enseñanza de las ciencias fisiológicas.

It is the author's thesis that the knowledge imparted in universities is being increasingly fragmented into a multitude of disciplines, which results in graduates who are trained to perform very limited functions and hence are impeded from developing their full potential. He refers to the position of the physiological sciences in the medical school curriculum and emphasizes the importance of moving from the concrete to the abstract and then back to the concrete in the study of these sciences. He discusses the need to change the institutional structure of the university in order to move away from this "disciplinary" approach to the imparting of knowledge. He feels that a change of this kind should be based on analysis, from a historical and interdisciplinary standpoint, of the concrete problems that arise in every part of society.