Although it has been demonstrated that nitric oxide (NO) released from sodium nitrite induces tetanic fade in the cat neuromuscular preparations, the effect of L-arginine on tetanic fade and its origin induced by NO have not been studied in these preparations. Furthermore, atropine reduces tetanic fade induced by several cholinergic and anticholinergic drugs in these preparations, whose mechanism is suggested to be mediated by the interaction of acetylcholine with inhibitory presynaptic muscarinic receptors. The present study was conducted in cats to determine the effects of L-arginine alone or after pretreatment with atropine or 1H-[1,2,4]oxadiazole [4,3-a]quinoxalin-1-one (ODQ) on neuromuscular preparations indirectly stimulated at high frequency. Drugs were injected into the middle genicular artery. L-arginine (2 mg/kg) and S-nitroso-N-acetylpenicillamine (SNAP; 16 µg/kg) induced tetanic fade. The N<FONT FACE="Symbol">w</font>-nitro-L-arginine (L-NOARG; 2 mg/kg) alone did not produce any effect, but reduced the tetanic fade induced by L-arginine. D-arginine (2 mg/kg) did not induce changes in tetanic fade. The tetanic fade induced by L-arginine or SNAP was reduced by previous injection of atropine (1.0 µg/kg) or ODQ (15 µg/kg). ODQ alone did not change tetanic fade. The data suggest that the NO-synthase-GC pathway participates in the L-arginine-induced tetanic fade in cat neuromuscular preparations. The tetanic fade induced by L-arginine probably depends on the action of NO at the presynaptic level. NO may stimulate guanylate cyclase increasing acetylcholine release and thereby stimulating presynaptic muscarinic receptors.

The sterile insect technique (SIT) is widely utilized in the biological control of fruit flies of the family Tephritidae, particularly against theMediterranean fruit fly.This study investigated the interaction between mating success and morphometric variation in the wings and the production of acoustic signals among three male groups of Ceratitis capitata (Wiedemann): (1) wild males, (2) irradiated with Co-60 (steriles), and (3) irradiated (steriles) and treated with ginger oil.Thecanonical variate analysis discriminated two groups (males irradiated andmales wild), based on themorphological shape of the wings. Amongmales that emit buzz signals, wild males obtained copulation more frequently than males in Groups 2 and 3.The individuals of Group 3 achieved more matings than those inGroup 2.Wild males displayed lower pulse duration, higher intervals between pulses, and higher dominant frequency. Regarding the reproductive success, the morphological differences in the wings? shape between accepted and nonaccepted males are higher in wildmales than in the irradiated ones. The present results can be useful in programs using the sterile insect technique for biological control of C. capitata.

Abstract A study of the physical performance of seven different professional groups living in the Brazilian Amazon was performed. The level of the physical capacity was measured using the ergometric bicycle. The professional groups (10 persons each) were the following: military groups, rural workers, river workers from the fluvial harbor of the city of Belém, primitive Kayapó indians. The other groups were professional soccer players, sedentary working persons and urban workers — 5 people of each. The best physical capacity was obtained by the soccer players and military groups. In second place, having small differences were the remaining groups, except the sedentaries. These persons revealed very low physical performance. As a general generalization the amazonians, although living in an environment of very high temperatures and humidity, are in about the same physical condition as those living in the interior of State of São Paulo (city of Ribeirão Preto). The amazonian rural workers reached better physical condition when compared to those studied in the State of São Paulo. Our preliminary explanation for such a result is the ingestion of a more balanced diet by the amazonians who have mainly high protein intake. The primitive Kayapó indians, perhaps studied for the first time, showed a physical performance comparable with the average of the other workers.

O presente estudo avalia a resposta de cepas de Plasmodium falciparum às drogas antimaláricas, através de testes in vitro, isoladas em 7 municípios do sul do Estado do Pará. Foram efetuados 69 testes para cloroquina e mefloquina, 62 para amodiaquina e 61 para quinino. Os resultados mostram elevada resistência para cloroquina (71%), relativamente baixa resistência para amodiaquina com (25,8%) e para o quinino apenas 8,2%. Mefloquina revela ampla sensibilidade (100%), mas, demonstrando perda da mesma quando comparada em dois períodos distintos. Evidenciou-se também cepas multirresistentes em dois dos municípios estudados.

Este estudo avalia a evolução da sensibilidade in vitro do Plasmodium falciparum em uma área de prospecção de ouro no Estado do Amapá no período de 1983 a 1990. Foram efetuados 75 testes para cloroquina e quinino, 74 para amodiaquina e 76 para mefloquina. Os resultados revelaram 81% de resistência à cloroquina e 27% para a amodiaquina, enquanto que para quinino e mefloquina não foram evidenciadas cepas resistentes. Contudo, para estas duas últimas drogas identificou-se uma crescente perda da sensibilidade ao longo do tempo. Aparentemente observa-se uma associação entre resistência à cloroquina e a diminuição da sensibilidade ao quinino.

ABSTRACT Advection-diffusion equations are widely used in modeling a diverse range of problems. These mathematical models consist in a partial differential equation or system with initial and boundary conditions, which depend on the phenomena being studied. In the modeling, boundary conditions may be neglected and unnecessarily simplified, or even misunderstood, causing a model not to reflect the reality adequately, making qualitative and/or quantitative analyses more difficult. In this work we derive a general linear flux dependent boundary condition for advection-diffusion problems and show that it generates all possible boundary conditions, according to the outward flux on the boundary. This is done through an integral formulation, analyzing the total mass of the system. We illustrate the exposed cases with applications willing to clarify their meanings. Numerical simulations, by means of the Finite Difference Method, are used in order to exemplify the different boundary conditions’ impact, making it possible to quantify the flux along the boundary. With qualitative and quantitative analysis, this work can be useful to researchers and students working on mathematical models with advection-diffusion equations.

Although healthy preterm infants frequently seem to be more attentive to visual stimuli and to fix on them longer than full-term infants, no difference in visual acuity has been reported compared to term infants. We evaluated the contrast sensitivity (CS) function of term (N = 5) and healthy preterm (N = 11) infants at 3 and 10 months of life using sweep-visual evoked potentials. Two spatial frequencies were studied: low (0.2 cycles per degrees, cpd) and medium (4.0 cpd). The mean contrast sensitivity (expressed in percentage of contrast) of the preterm infants at 3 months was 55.4 for the low spatial frequency (0.2 cpd) and 43.4 for the medium spatial frequency (4.0 cpd). At 10 months the low spatial CS was 52.7 and the medium spatial CS was 9.9. The results for the term infants at 3 months were 55.1 for the low spatial frequency and 34.5 for the medium spatial frequency. At 10 months the equivalent values were 54.3 and 14.4, respectively. No difference was found using the Mann-Whitney rank sum T-test between term and preterm infants for the low frequency at 3 or 10 months or for the medium spatial frequency at 3 or 10 months. The development of CS for the medium spatial frequency was equally fast for term and preterm infants. As also observed for visual acuity, CS was equivalent among term and preterm infants, suggesting that visual experience does not modify the development of the primary visual pathway. An earlier development of synapses in higher cortical visual areas of preterm infants could explain the better use of visual information observed behaviorally in these infants.

Abstract: The objective of this study was to compare the effect of hormonal treatment duration through the use of intravaginal sponges impregnated with 60 mg MAP for 6 (G6; n = 10), 9 (G9; n = 10) or 12 (G12; n = 10) days. All nulliparous (n = 15) and lactating (n = 15) Saanen goats received 37.5 µg d-cloprostenol and 200 IU eCG 24 hours before sponge removal during the nonbreeding season. After sponge removal, estrus was monitored twice a day (06h00 and 18h00) by the use of fertile bucks. Transrectal ovarian ultrasonography was performed after device removal until ovulation detection. All goats were bred by artificial insemination (AI) or natural breeding (NB). All females received 250 IU hCG 5 d after AI or NB. No difference was observed among groups G6, G9 and G12 for: estrous response (90.0, 100.0 and 100.0%, respectively); interval from sponge removal to estrus (26.7±5.6, 25.2±2.8 and 25.2±3.3 hours), duration of estrus (28.5±7.1; 21.6±3.0 and 25.2±6.1 hours); ovulation rate (80.0, 100.0 and 70.0%); number of ovulations (1.9±0.2, 1.5±0.2 and 1.4±0.2); and pregnancy rate (60.0, 80.0 and 50.0%). Interval from sponge removal to ovulation was shorter in animals from G6 (44.6±2.2 hours) than for animals from G9 (52.8±2.7 hours) and G12 (60.0±4.5 hours). All treatments were effective in the induction of synchronized estrus in Saanen goats during the nonbreeding season, but ovulation occurred earlier when goats received sponges for 6 days.