PubMed · 1267598
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
W B Kiesewetter, A H Bill, H H Nixon, T V Santulli. 1976. Imperforate anus.. https://doi.org/10.1001/archsurg.1976.01360230018003
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Cataract prevalence increases with age. As the world's population ages, cataract-induced visual dysfunction and blindness is on the increase. This is a significant global problem. The challenges are to prevent or delay cataract formation, and treat that which does occur. Genetic and environmental factors contribute to cataract formation. However, reducing ocular exposure to UV-B radiation and stopping smoking are the only interventions that can reduce factors that affect the risk of cataract. The cure for cataract is surgery, but this is not equally available to all, and the surgery which is available does not produce equal outcomes. Readily available surgical services capable of delivering good vision rehabilitation must be acceptable and accessible to all in need, no matter what their circumstances. To establish and sustain these services requires comprehensive strategies that go beyond a narrow focus on surgical technique. There must be changes in government priorities, population education, and an integrated approach to surgical and management training. This approach must include supply of start-up capital equipment, establishment of surgical audit, resupply of consumables, and cost-recovery mechanisms. Considerable innovation is required. Nowhere is this more evident than in the pursuit of secure funding for ongoing services.
Factors in the environment appear to be responsible for inducing many of the cell fates in the retina, including, for example, photoreceptors. Further, there is a conserved order of histogenesis in the vertebrate retina, suggesting that a temporal mechanism interacts in the control of cellular determination. The temporal mechanism involved could result from different inducing signals being released at different times. Alternatively, the inducing signals might be present at many stages, but an autonomous clock could regulate the competence of cells to respond to them. To differentiate between these mechanisms, cells from young embryonic retinas were dissociated and grown together with those from older embryos, and the timing of photoreceptor determination assayed. Young cells appeared uninfluenced by older cells, expressing photoreceptor markers on the same time schedule as when cultured alone. A similar result was obtained when the heterochronic mixing was done in vivo by grafting a small plug of optic vesicle from younger embryos into older hosts. Even the graft cells at the immediate margin of the transplant failed to express photoreceptor markers earlier than normal, despite their being in contact with older, strongly expressing host cells. We conclude that retinal progenitors intrinsically acquire the ability to respond to photoreceptor-inducing cues by a mechanism that runs on a cell autonomous schedule, and that the conserved order of histogenesis is based in part on this competence clock.
Post-mortem examinations of 236 goats from all provinces in Mongolia were performed for the study of helminths in goats. Thirty-nine helminth species belonging to three classes, 14 families and 23 genera were found. Trichocephalus spiralis and Avitellina centripunctata are reported for the first time in goats in Mongolia. The prevalence and intensity of helminth infections are reported for three age groups of goats in four seasons and three geographic zones in Mongolia. Common helminth infections of goats in all zones of Mongolia were infections of Ostertagia, Marshallagia and Nematodirus. In addition, fecal samples of 15 kids, 15 yearlings and 15 adult goats were examined monthly for eggs. The highest number of eggs per gram (EPG) of feces was counted in March (average 1335.3+/-405.3) and the lowest count was in November (54+/-18.6).