SECOND LATIN AMERICAN INTERCOMPARISON ON INTERNAL DOSE ASSESSMENT.

Internal dosimetry intercomparisons are essential for the verification of applied models and the consistency of results'. To that aim, the First Regional Intercomparison was organised in 2005, and that results led to the Second Regional Intercomparison Exercise in 2013, which was organised in the frame of the RLA 9/066 and coordinated by Autoridad Regulatoria Nuclear of Argentina. Four simulated cases covering intakes of (131)I, (137)Cs and Tritium were proposed. Ninteen centres from thirteen different countries participated in this exercise. This paper analyses the participants' results in this second exercise in order to test their skills and acquired knowledge, particularly in the application of the IDEAS Guidelines. It is important to highlight the increased number of countries that participated in this exercise compared with the first one and, furthermore, the improvement in the overall performance. The impact of the International Atomic Energy Agency (IAEA) Projects since 2003 has led to a significant enhancement of internal dosimetry capabilities that strengthen the radiation protection of workers.

[Theoretical model of a cost-effectiveness analysis of combined enalapril-nitrendipine therapy for treating hypertension]. / Modelo teórico de análisis coste-efectividad de la terapia combinada de enalapril-nitrendipino en el tratamiento de la hipertensión arterial.

OBJECTIVE: Cost-effectiveness analysis of combined enalapril-nitrendipine therapy (E/N), as second-line therapy for light or moderate hypertension. DESIGN: Theoretical model of cost-effectiveness, based on the norms of hypertension treatment in primary care, the considered view of a panel of experts and the direct costs of health resources and purchase of medication. SETTING: Spanish National Health system. PARTICIPANTS: Simulation of 1000 patients with hypertension, with a time horizon of one year. INTERVENTIONS: After a prior failure of the first-line treatment with either enalapril or nitrendipine, an evaluation was made of the possibilities of increasing dosage of the first-line treatment, changing the drug or administering the E/N combination. MAIN MEASUREMENT: The likelihoods, in the primary care context, of controlling diastolic pressure, of abandonment and of using the two strategies or not were measured, as were the use of health resources in each situation, and costs of resource use and of medication. RESULTS: The cost-effectiveness quotient of the combined E/N treatment was consistently more efficient than the increase in dose or change to another drug. This was so, whether the treatment was started with enalapril (301.06 euros vs 337.97 euros and 588.42 euros) or with nitrendipine (331.5 euros vs 469.88 euros and 579.76 euros). CONCLUSIONS: Combined therapy (E/N) is, on the basis of the assumptions made in the model, an efficient therapy option. Therefore, it can be recommended for prescription.

Nitrendipine and enalapril combination therapy in mild to moderate hypertension: assessment of dose-response relationship by a clinical trial of factorial design.

Hypertension is an important cardiovascular risk factor and the goal of its pharmacologic treatment is to reduce morbidity and mortality. Treatment is usually initiated with a low dose of a single agent and titrated to a higher dose as required. As many as 50% of patients require the addition of a second agent to achieve satisfactory blood pressure control. The aim of this study was to assess the dose-response relationship of nitrendipine and enalapril alone or in fixed combination in the treatment of mild to moderate hypertension. A total of 496 patients were enrolled in a multicenter, randomized, double-blind, factorial-design, parallel-group clinical trial comparing placebo, nitrendipine (5, 10, and 20 mg) and enalapril (5, 10, and 20 mg) alone or in combination. After a single-blind, 2-week placebo run-in period, 414 patients whose diastolic blood pressure ranged between 90-109 mm Hg were randomly assigned to a treatment group. The combination of nitrendipine and enalapril, particularly regimens including nitrendipine 20 mg and enalapril 5 or 10 mg, were significantly superior to both monotherapies; mean diastolic blood pressure reductions from baseline to last visit were -12.5 and -14.3 mm Hg, respectively. Response surface analysis provided further evidence that these combinations were optimal in terms of anti-hypertensive efficacy. All treatments were well tolerated and the incidence of adverse events did not differ significantly between groups. In summary, the anti-hypertensive efficacy of the combination was found to be superior to both monotherapies at any doses. The dose combination achieving the greatest blood pressure reduction was nitrendipine 20 mg and enalapril 10 mg.

Assessment of the diagnostic value of 99mTc-radiolabelled specific antibodies in experimental hydatidosis.

We assessed the potential of 99mTc labelled specific polyclonal antibodies (99mTc-PoAb) for the diagnosis of hydatid disease by immunoscintigraphy. Experimentally infected mice and rabbits were used for this purpose. A specific rabbit antibody recognizing total somatic antigen from hydatid membranes (HCMA) was obtained. PoAb biological activity before labelling was checked according to Barbieri et al. 99mTc-PoAb labelling was performed according to Thakur et al.; the radiochemical purity was higher than 90%. The following studies of 99mTc-PoAb were made: post-labelling biological activity; in vitro stability; blood and renal kinetics in normal mice up to 24 hours after intravenous (i.v.) and intraperitoneal (i.p.) administration; biodistribution in normal and infected mice after i.p. or i.v. injection, and in rabbits after i.v. administration. Biodistribution studies in normal mice, after both administration routes, showed considerable hepatic uptake of activity. An important uptake in cysts after i.p. administration in mice, indicating successful targeting, was also confirmed by autoradiography images. Intravenously administered 99mTc PoAb was not significantly targeted to peritoneal cysts in either animal species, due to inherent limitations to these animal models. Results obtained with i.p. administration suggest that specific hydatid imaging may be possible. Both the mice and rabbit models revealed hepatic uptake which, combined with the short isotope half-life, prevent the drawing of any final conclusions regarding the usefulness of 99mTc-labelling in hydatid disease.

[Fertility decline and female labor force participation in Mexico]. / Descenso de la fecundidad y participacion laboral femenina en Mexico.

PIP: Data from the 1976 Mexican Fertility survey and the 1987 National survey of Fertility and Health are the basis for an analysis of the relationship between the fertility decline and female labor force participation in Mexico. The two surveys provide relatively comparable data on economic activity at the time of the interview, before the first union, and before the first birth. Other data on female labor force participation in Mexico is scarce and does not usually consider the relationship to fertility. The characteristics of Mexico's fertility decline and the evolution of female labor force participation are separately examined as background for the analysis of the effect of fertility decline on economic activity. Mexican fertiity remained elevated until around 1970, when the rapid and significant decline began. The total fertility rate dropped from 6.8 in 1970 to 3.8 in 1986, a 44% decline in 16 years. Urban women born in 1942-47 were the first to limit their family size and terminate childbearing at younger ages. Little recent variation has occurred in the age at marriage or at birth of the first child. But place of residence and educational status are associated with significant differentials in age at marriage and initiation of childbearing. The greatest changes in patterns of family formation have occurred in final family size and age at termination of childbearing. The proportion of Mexican women over age 12 who declared themselves economically active increased from 13% in 1950 to 32% in 1988. After 1970, the greatest fertility declines were in women over 30, while the greatest increases in economic activity were in young women; only during 1982-87 did participation increase for women aged 30-44. Activity rates have increased constantly beginning with the 1942-47 cohorts. The increase for the 1942-47 cohort began after age 35, when over half the women had had their last child. Women born in 1947-52 began to increase their participation at 30-34 years, but their increase was even greater at 35-39 years. Women born in 1952-57 demonstrated an important increase in participation at 25-29 years and especially at 30-34 years. An increasing proportion of women in the youngest cohorts have been able to begin their families and participate in the labor force simultaneously. Women who worked before marriage or at early stages of family formation are particularly likely to reenter the labor force.^ieng

Economic benefits of controlling internal and external parasites in South American camelids.

A trial was carried out in alpacas (Lama pacos) and llamas (Lama glama) to determine the economic benefits of controlling both external and internal parasites by the use of ivermectin ("Ivomec," Merck Sharp & Dohme). After four months the treated male alpacas gained on average 3.1 kg more than the untreated males, and their fleece weighed 0.36 kg more. The treated female alpacas gained 1.9 kg more than the controls, but their fleece weighed 0.03 kg less. This treatment gave a net financial benefit to the farmer of U.S. $3.54 for each of his male alpacas and U.S. $1.36 for each of his female alpacas. The results for the llamas were not significant because there was great variation in the weight gains (and losses). Because the value of llama fleece is less, the economic benefits were also less.

Effects of parasitic infestation on the productivity of alpacas (Lama pacos).

A trial was carried out in alpacas (Lama pacos) to determine the economic benefit of controlling both external and internal parasites using ivermectin (Ivomec, Merck, Sharpe and Dohme). After four months the treated male alpacas had gained on average 3.1 kg more than the untreated males and their fleece weighed 0.36 kg more. Treated females gained 1.9 kg more than the controls but their fleece weighed 0.03 kg less. This resulted in a net financial benefit to the farmer of US$3.54 for each male alpaca and US$1.36 for each female.

[Introduction: the demographic transition in the 1980s]. / Introduccion: la transicion demografica en la decada de los ochenta.

PIP: The authors review aspects of Mexico's demographic transition, with a focus on the 1980s. Population politics, contraceptive use patterns, changes in overall and infant mortality, and increased female labor force participation are considered as contributory factors to this transition.^ieng