Eggs viability of Aedes aegypti Linnaeus (Diptera, Culicidae) under different environmental and storage conditions in Manaus, Amazonas, Brazil / Viabilidade de ovos de Aedes aegypti (Diptera, Culicidae) em diferentes condições de armazenamento em Manaus, Amazônia, Brasil

Abstract The viability of Aedes aegypti eggs was assessed in the Amazon region. The eggs were maintained under different conditions: indoors (insectarium) and outdoors (natural environment), as well as in different storage types (plastic cup, paper envelope, plastic bag) for different days. Egg viability was measured as the mean of hatchings observed from egg-bearing sheets of filter paper immersed in water, using three sheets randomly selected from each storage type and at both sites. There were significant differences in the viability of Ae. aegypti eggs with respect to the location (F=30.40; DF=1; P<0.0001), storage type (F=17.66; DF=2; P<0.0001), and time of storage (F=49.56; DF=9; P<0.0001). The interaction between storage site versus storage type was also significant (F=15.96; DF=2; P<0.0001). A higher hatching mean was observed for the eggs kept in the insectarium than for those outdoors (32.38 versus 7.46). Hatching rates of egg batches stored for 12 to 61 days ranged between 84 and 90%. A reduction was observed between 89 and 118 days, with values of 63 and 48%, respectively. With respect to type of storage, mean egg hatching was higher for the eggs in plastic cups (44.46). It was concluded that the viability of the eggs of Ae. aegypti in the Amazon region remains high up to 4 months, after which it declines drastically, although in this study hatching occurred for up to 8 months in very low percentages.

Resumo Testou-se a viabilidade dos ovos de Ae. aegypti na região amazônica armazenados em copos plásticos, envelopes de papel e sacos plásticos que foram mantidos em área interna e em área externa por dias diferentes. Verificaram-se diferenças significativas na viabilidade dos ovos considerando-se a localização (F=30,40; GL=1; P<0,0001), os tipos de armazenamento (F=17,66; GL=2; P<0,0001) e os tempos (F=49,56; GL=9; P<0,0001) e na interação localização versus tipo de armazenamento (F=15,96; GL=2; P<0,0001). A média de eclosão dos ovos armazenados no insetário foi maior: 32,38, do que a dos lotes armazenados na área externa: 7,46. As taxas de eclosão dos ovos armazenados de 12 a 61 dias ficaram entre 90% e 84% com reduções a partir de 89 e 118 dias, quando atingiu de 63% e 48%, respectivamente. Em relação aos tipos de armazenamento a média de ovos dos copos foi significativa (44,46). Conclui-se que a viabilidade dos ovos de Ae. aegypti na região amazônica é mantida em níveis elevados até 4 meses, e a partir daí ocorrem reduções drásticas, com eclosões até 8 meses em percentuais muito baixos.

Association of the Lipoprotein Lipase S447X and Neuropeptide Y Leu7Pro Genetic Polymorphisms with the Lipid Profiles of Individuals with and without Evidence of Coronary Artery Disease.

Background: Coronary artery disease (CAD) is a multifactorial disease whose etiogenesis involves a number of environmental, genetic and lifestyle-related factors. Genetic polymorphisms are noteworthy among these factors because they alter gene expression and, thus, the functions of the respective products. Methods: A case-control study was conducted in the Cardiology Institute, with 79 subjects classified as cases with CAD, and 96 subjects as controls without CAD or other disease. In this study, we evaluated the association between the single-nucleotide polymorphisms (SNPs) of S447X and Leu7Pro of the lipoprotein lipase (LPL) and neuropeptide Y (NPY) genes, respectively. Results: No differences were found in the frequencies of LPL SNP between the cases and controls. However, the LPL 447X allele carriers exhibited a near-significant difference in the triglycerides (p=0.086) and higher mean in the HDL-c (p=0.018). NPY polymorphisms proved to be infrequent in this study population, and no significant difference was observed between the groups. Conclusions: Our findings provide further support of the genetic polymorphisms effect on the lipid metabolism control. So, further studies are needed to assess the functional effect of this and other polymorphisms, on LPL and in the NPY activity, and their impact on CAD risk.

Looking for the GAP effect in manual responses and the role of contextual influences in reaction time experiments

When the offset of a visual stimulus (GAP condition) precedes the onset of a target, saccadic reaction times are reduced in relation to the condition with no offset (overlap condition) - the GAP effect. However, the existence of the GAP effect for manual responses is still controversial. In two experiments using both simple (Experiment 1, N = 18) and choice key-press procedures (Experiment 2, N = 12), we looked for the GAP effect in manual responses and investigated possible contextual influences on it. Participants were asked to respond to the imperative stimulus that would occur under different experimental contexts, created by varying the array of warning-stimulus intervals (0, 300 and 1000 ms) and conditions (GAP and overlap): i) intervals and conditions were randomized throughout the experiment; ii) conditions were run in different blocks and intervals were randomized; iii) intervals were run in different blocks and conditions were randomized. Our data showed that no GAP effect was obtained for any manipulation. The predictability of stimulus occurrence produced the strongest influence on response latencies. In Experiment 1, simple manual responses were shorter when the intervals were blocked (247 ms, P < 0.001) in relation to the other two contexts (274 and 279 ms). Despite the use of choice key-press procedures, Experiment 2 produced a similar pattern of results. A discussion addressing the critical conditions to obtain the GAP effect for distinct motor responses is presented. In short, our data stress the relevance of the temporal allocation of attention for behavioral performance.

Experimental context modulates warning signal effects

Previous studies have shown that saccadic eye responses but not manual responses were sensitive to the kind of warning signal used, with visual onsets producing longer saccadic latencies compared to visual offsets. The aim of the present study was to determine the effects of distinct warning signals on manual latencies and to test the premise that the onset interference, in fact, does not occur for manual responses. A second objective was to determine if the magnitude of the warning effects could be modulated by contextual procedures. Three experimental conditions based on the kind of warning signal used (visual onset, visual offset and auditory warning) were run in two different contexts (blocked and non-blocked). Eighteen participants were asked to respond to the imperative stimulus that would occur some milliseconds (0, 250, 500 or 750 ms) after the warning signal. The experiment consisted in three experimental sessions of 240 trials, where all the variables were counterbalanced. The data showed that visual onsets produced longer manual latencies than visual offsets in the non-blocked context (275 vs 261 ms; P < 0.001). This interference was obtained, however, only for short intervals between the warning and the stimulus, and was abolished when the blocked context was used (256 vs 255 ms; P = 0.789). These results are discussed in terms of bottom-up and top-down interactions, mainly those related to the role of attentional processing in canceling out competitive interactions and suppressive influences of a distractor on the relevant stimulus.

Risk of hepatitis B virus transmission by diagnostic hysteroscopy

Few data are available in the literature concerning the efficacy of standard hysteroscope disinfection procedures to prevent hepatitis B transmission. The aim of the present study was to determine the risk of hepatitis B virus (HBV) transmission during hysteroscopy among anti-HBc-seropositive women. Serum and hysteroscopic samples were collected from 62 women after diagnostic hysteroscopy. All samples were tested for serologic HBV markers. Polymerase chain reactions (PCR) were carried out to amplify regions C and S of the viral genome and only samples amplified by both pairs of primers were considered to be positive. Anti-HBc was repeatedly reactive in 48 (77 percent) of 62 serum samples, and HBsAg was detected in 8 (13 percent). At least one HBV serologic marker was found in 49 (79 percent) samples. Only one sample was HBsAg positive and anti-HBc negative. HBV-DNA was detected by PCR in 7 serum samples but in only 3 hysteroscopic samples obtained just after hysteroscopy. It is noteworthy that high levels of anti-HBc IgM were detected in one HBsAg-negative patient who showed an HBV-DNA-positive hysteroscopic sample. An elevated sample/cut-off ratio for anti-HBc IgM suggests recent infection and reinforces the need for testing for HBsAg and anti-HBc before hysteroscopy, since acute hepatitis B can be clinically asymptomatic. Viral DNA was not detected in any hysteroscopic samples collected after washing and disinfecting procedures with glutaraldehyde. We conclude that HBV-DNA can be found in the hysteroscope soon after hysteroscopy, but standard disinfecting procedures are effective in viral removal.

Behavioral modulation by mutilation pictures in women

Previous studies have shown that women are more emotionally expressive than men. It is unclear, however, if women are also more susceptible to the emotional modulation of behavior imposed by an affective stimulus. To investigate this issue, we devised a task in which female subjects performed six sequential trials of visual target detection following the presentation of emotional (mutilation and erotic) or neutral pictures (domestic utensils and objects) and compared the data obtained in the present study with those described in a previous study with male subjects. The experiment consisted of three blocks of 24 pictures and each block had an approximate duration of 4 min. Our sample consisted of 36 subjects (age range: 18 to 26 years) and each subject performed all blocks. Trials following the presentation of mutilation pictures (283 ms) had significantly slower reaction times than those following neutral (270 ms) pictures. None of the trials in the "pleasant block" (271 ms) was significantly different from those in the "neutral block". The increase in reaction time observed in the unpleasant block may be related in part to the activation of motivational systems leading to an avoidance behavior. The interference effect observed in this study was similar to the pattern previously described for men. Thus, although women may be more emotionally expressive, they were not more reactive to aversive stimuli than men, as measured by emotional interference in a simple reaction time task.

Gap effect and reaction time distribution: simple vs choice manual responses

It is well known that saccadic reaction times (SRT) are reduced when the target is preceded by the offset of the fixation point (FP) - the gap effect. Some authors have proposed that the FP offset also allows the saccadic system to generate a separate population of SRT, the express saccades. Nevertheless, there is no agreement as to whether the gap effect and express responses are also present for manual reaction times (MRT). We tested the gap effect and the MRT distribution in two different conditions, i.e., simple and choice MRT. In the choice MRT condition, subjects need to identify the side of the stimulus and to select the appropriate response, while in the simple MRT these stages are not necessary. We report that the gap effect was present in both conditions (22 ms for choice MRT condition; 15 ms for simple MRT condition), but, when analyzing the MRT distributions, we did not find any clear evidence for express manual responses. The main difference in MRT distribution between simple and choice conditions was a shift towards shorter values for simple MRT.

Onset and offset of a visual cue have different effects on manual reaction time to a visual target

Simple reaction time (RT) to a peripheral visual target is shortened when a non-informative cue is flashed at target location 100-150 ms before target onset (early facilitation). Afterwards, RT to targets appearing at cue location is lengthened (inhibition of return). In the present study we have investigated if these effects arise from the onset and/or from the offset of the cue and the time-dependence of these effects. Twelve subjects were asked not to respond a non-informative cue (S1) appearing on a computer screen 6§ to the right or to the left of a fixation point (FP), but to respond, by pressing a key, to a target (S2) occurring at 4§ from the FP in the same hemifield as S1 or in the opposite hemifield. There were two different types of trials. In both, a brief auditory stimulus (W) occurring 700 ms after the onset of FP warned the subject that S2 would appear 100, 200, 300, 500 or 800 ms later. Trials where the onset of S1 coincides with W and S1 remains on until the response to S2 are called ON trials. In OFF trials, S1 onset occurs at the beginning of the trial and its offset coincides with W. We found that in On trials, RTs to S2 occurring ipsi-or contralaterally to S1 did not differ. In contrast, S1 offset elicited an inhibition of its hemifield beginning at least 100 ms after S1 offset and extending up to 800 ms

Spatial distribution of the inhibition elicited by the offset of a visual cue on manual reaction time to a visual target

Simple reaction time (RT) to a peripheral visual target (S2) is shortened when a non-informative cue (S1) is flashed at the S2 location 100-150 ms before target onset (early facilitation). Afterwards, RTs to targets appearing at the S1 location are lengthened (inhbition of return). In the present investigation we studied the spatial distribution of the inhibition elicited by the offset of S1. Twelve subjects were asked not to respond to S1 which appeared on a horizontal meridian located 5.5§ above the fixation point (FP), but to respond, by pressing a key, to a target (S2) occurring at 5.5§ to the left or to the right. S1 could appear at one of 9 locations along this meridian (5.5, 3.5, 1.5, and 0.5§ to the left, 0.0 and 0.5, 1.5, 3.5, and 5.5§ to the right) and S2 occurred only at the most eccentric positions. Each trial began with the presentation of FP. Five-hundred ms later, S1 appeared and remained on for 700 ms. One hundred or 800 ms after S1 offset, S2 appeared in the same or in the opposite hemifield. We found that the offset of S1 elicits an inhibition (OFF-inhibition) which has the following features: a) it is maximal at cue's position; b) it spreads to other positions in the cued hemifield, and c) it decreases when the time interval between S1 offset and S2 onset increases from 100 to 800 ms