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Out of 2,343 examined sheep throughout the whole year, 271 were found to be infected with tapeworms (11.5%). The highest infection rate (22.1%) was recorded in autumn, while the lowest (6%) occurred in summer. Six species of cestodes were identified according to their prevalence: Moniezia expansa (74%), Moniezia denticulata (8.5%), Moniezia benedeni (4.8%), Moniezia trigonophora (2.7%), and Thysaniezia giardi (2.7%), T. giardi was recorded in Egypt for the first time. M. expansa was found throughout the year with two peaks in January (92.3%) and June (88.5%). SEM examination revealed that M. expansa scolex has four triangular suckers guarded by an X-shaped fibrous band that makes them open permanently. Also, there is a Y-shaped apical part at the scolex center which may be an embryonically non-developed rostellum. The whole worm body surface is covered with unidirectional microtriches. TEM showed that the tegument is underlaid by a thick fibrous interstitial layer below which an outer circular and an inner longitudinal muscular layer are arranged. Beneath these structures the subtegumental cells are found which have spherical electron-dense inclusions and various other cell organelles. Moreover, M. expansa has interproglottidal glands which contain secretory vesicles and secretions. For biological control of this parasite, different concentrations of crude plant extract of Artemisia cina were used in vitro and in vivo. In vitro, the results indicated that the plant extract is efficacious at all concentrations tested. Electron microscopic examination showed that many structures of the treated worms were affected. The most affected sites were the scolex and the microtriches of the outer tegumental surface. In vivo, treatment of heavily infected animals showed an antihelminthic effect, since the complete absence of eggs was recorded 9 days after treatment when fecal investigations were done.

IntroductionSelf-directed learning (SDL) and problem-based learning (PBL) are fundamental tools to achieve lifelong learning in an integrated medical curriculum. However, the efficacy of SDL in some clinical courses is debated.AimThe aim of the study was to measure the effectiveness of SDL for an ophthalmology course in comparison with PBL.MethodsA cross-sectional study was conducted with fifth-year medical students enrolled in an ophthalmology course. SDL comprised four case-based scenarios guided by several questions. PBL comprised three sessions. An ear, nose, and throat (ENT) course was selected for comparison as a control. At the end of the course, 30 multiple-choice questions (MCQs) for both SDL and PBL were assessed and analyzed against their counterparts in the ENT course by an independent t-test.ResultsFor the SDL component of the ophthalmology course, the number and percentages of students attaining high (n = 6/60, 10%) and moderate (n = 15/60, 28.3%) scores on an MCQs written exam were evaluated. For the PBL component, high scores were seen for 23.3% (n = 14/60), and moderate scores for 33.3% (n = 20/60) of the participants. For the SDL component of the ENT course, the number and percentages of students attaining high (n = 14/60, 23.3%) and moderate (n = 17/60, 28.3%) scores were recorded. For the PBL component, high (16/60, 26.6%) and moderate (17/60, 28%) scores were recorded. Significant p-values were obtained between the results for SDL and PBL in the ophthalmology course (p = 0.009), as well as between SDL results for both courses (p = 0.0308). Moreover, differences between the SDL results of ophthalmology and the PBL results of ENT (p = 0.0372) were significant.ConclusionSDL appears to be less valuable for promotion of self-readiness. Periodic discussions in small groups or by panel discussion are strongly recommended for students to enhance readiness with SDL.

Mutations in the Trypanosoma brucei aquaporin AQP2 are associated with resistance to pentamidine and melarsoprol. We show that TbAQP2 but not TbAQP3 was positively selected for increased pore size from a common ancestor aquaporin. We demonstrate that TbAQP2's unique architecture permits pentamidine permeation through its central pore and show how specific mutations in highly conserved motifs affect drug permeation. Introduction of key TbAQP2 amino acids into TbAQP3 renders the latter permeable to pentamidine. Molecular dynamics demonstrates that permeation by dicationic pentamidine is energetically favourable in TbAQP2, driven by the membrane potential, although aquaporins are normally strictly impermeable for ionic species. We also identify the structural determinants that make pentamidine a permeant although most other diamidine drugs are excluded. Our results have wide-ranging implications for optimising antitrypanosomal drugs and averting cross-resistance. Moreover, these new insights in aquaporin permeation may allow the pharmacological exploitation of other members of this ubiquitous gene family.