Quality control of Toxoplasma gondii in meat packages: Standardization of an ELISA test and its use for detection in rabbit meat cuts

Toxoplasma gondii causes severe disease both to man and livestock and its detection in meat after slaughtering requires PCR or biological tests. Meat packages contain retained exudate that could be used for serology due to its blood content. Similar studies reported false negative assays in those tests. We standardized an anti-T. gondii IgG ELISA in muscle juices from experimentally infected rabbits, with blood content determination by cyanhemoglobin spectrophotometry. IgG titers and immunoblotting profiles were similar in blood, serum or meat juice, after blood content correction. These assays were adequate regardless of the storage time up to 120 days or freeze-thaw cycles, without false negative results. We also found 1.35% (1/74) positive sample in commercial Brazilian rabbit meat cuts, by this assay. The blood content determination shows ELISA of meat juice may be useful for quality control for toxoplasmosis monitoring. (C) 2011 Elsevier Ltd. All rights reserved.

Modelling the control strategies against dengue in Singapore

Notified cases of dengue infections in Singapore reached historical highs in 2004 (9459 cases) and 2005 (13 817 cases) and the reason for such all increase is still to be established. We apply a mathematical model for dengue infection that takes into account the seasonal variation in incidence, characteristic of dengue fever, and which mimics the 2004-2005 epidemics in Singapore. We simulated a set of possible control strategies and confirmed the intuitive belief that killing adult mosquitoes is the most effective strategy to control an ongoing epidemic. On the other hand, the control of immature forms was very efficient ill preventing the resurgence of dengue epidemics. Since the control of immature forms allows the reduction of adulticide, it seems that the best strategy is to combine both adulticide and larvicide control measures during an outbreak, followed by the maintenance of larvicide methods after the epidemic has subsided. In addition, the model showed that the mixed strategy of adulticide and larvicide methods introduced by the government seems to be very effective in reducing the number of cases in the first weeks after the start of control.

Effects of semen storage and separation techniques on sperm DNA fragmentation

Objective: To determine the effect of semen storage and separation techniques on sperm DNA fragmentation. Design: Controlled clinical study. Setting: An assisted reproductive technology laboratory. Patient(s): Thirty normoozospermic semen samples obtained from patients undergoing infertility evaluation. Intervention(s): One aliquot from each sample was immediately prepared (control) for the sperm chromatin dispersion assay (SCD). Aliquots used to assess storage techniques were treated in the following ways: snap frozen by liquid nitrogen immersion, slow frozen with Tris-yolk buffer and glycerol, kept on ice for 24 hours or maintained at room temperature for 4 and 24 hours. Aliquots used to assess separation techniques were processed by the following methods: washed and centrifuged in media, swim-up from washed sperm pellet, density gradient separation, density gradient followed by swim-up. DNA integrity was then measured by SCD. Main Outcome Measure(s): DNA fragmentation as measured by SCD. Result(s): There was no significant difference in fragmentation among the snap frozen, slow frozen, and wet-ice groups. Compared to other storage methods short-term storage at room temperature did not impact DNA fragmentation yet 24 hours storage significantly increased fragmentation. Swim-up, density gradient and density gradient/swim-up had significantly reduced DNA fragmentation levels compared with washed semen. Postincubation, density gradient/swim-up showed the lowest fragmentation levels. Conclusion(s): The effect of sperm processing methods on DNA fragmentation should be considered when selecting storage or separation techniques for clinical use. (Fertil Steril (R) 2010;94:2626-30. (C) 2010 by American Society for Reproductive Medicine.)

Sibling competition and parental control: Patterns of begging in parrots

Begging and food allocation patterns are the outcome of complex and repeated interactions between parents and young. In most systems studied, food allocation is regulated by begging and scramble competition. In contrast, little is understood about how nestling solicitation behaviours will evolve in systems where parents engage in complex patterns of food allocation. Parrots appear to be an excellent group in which to examine the shifting balance between sibling competition and parental control. Studies to date have shown that levels of sibling competition within parrot broods are low, possibly in response to parental control over food distribution. I assess what is known about the function of nestling begging in parrots and evaluate why begging signals appear to function differently in this group.

Otitis media with effusion and dental occlusion: is there any relationship?

Aim Auditory tube dysfunction is one of the aetiological causes of otitis media. Studies suggest a correlation between otitis media with effusion and dental malocclusion. Our goal was to determine any correlation between dental malocclusion and otitis media with effusion in children with chronic upper airway obstruction due to tonsil and adenoid enlargement. Materials and methods This prospective study evaluated 52 children with otitis media with effusion and 48 without, aged 4.2 to 10.8 years. A questionnaire was answered by the parents about breast or bottle-feeding and bad oral habits. Malocclusion was diagnosed according to Angle`s classification for molar relationships in Classes I, II and III, posterior and anterior cross bite, open and deep bite, and overjet. Results and conclusion The results suggested no correlation between dental malocclusion and otitis media with effusion. Other potential confounders, such as breast or bottle-feeding and oral habits were also not correlated.