Organ specificity in the development of the epithelial lining of the oral cavity and esophagus

Epithelial lining of upper portion of alimentary tract differs sharply from other digestive system portions. This is associated primarily with the peculiarities of local processes of morphogenesis. Intertissular interactions, as well as changes in architectonics and differentiation of the structures, surrounding the epithelium, in particular mesenchymal cells, are of primary importance in morphogenesis of this portion. The organ specificity of the development of the oral and esophageal epithelium is due to their local peculiarities.     

Counselling for an HIV test

Doctors may feel uncomfortable with the prospect of discussing a human immunodeficiency virus (HIV) antibody test with their patient. This is in part because they do not enquire about high risk activity as part of a medical history. With increasing medical and public awareness of both the clinical manifestations and social implications of HIV infection, it is important that all doctors receive guidance on how to deal with these issues. Counselling is not the usual term used to describe obtaining informed consent. In the general medical setting, tests for hepatitis B and syphilis are routinely carried out without specific consent even though results of these tests may have profound effects on both the patient and their sexual partners. However society and ethical considerations have made HIV testing different. HIV testing will inevitably become more widespread, and thus become a more routine part of patient investigation and management.     

Secondary extradural spinal tumours in children

Secondary extradural spinal tumours are very rare, but they comprise most of the extradural neoplasms seen in infancy and childhood. Thirty-nine patients with this type of secondary tumour were treated in our hospital between 1965 and 1991. The diagnosis was proved by biopsy in every case. Following surgical decompression, all 35 survivors had radiotherapy and/or chemotherapy. Their outcome is reported.     

Posterior capsule polishing with the neodymium:YLF picosecond laser: model eye study

PURPOSE: To determine the ability and threshold energy of the neodymium:yttrium-lithium-fluoride (Nd:YLF) picosecond laser to achieve micron-level polishing of a latex posterior capsule facsimile (PCF) as an alternative to laser capsulotomy to treat posterior capsule opacification. SETTING: University of Rochester Medical Center, Rochester, New York, USA. METHODS: A solid-state, mode-locked Nd:YLF picosecond laser was used to polish a latex PCF in contact with a poly(methyl methacrylate) intraocular lens (IOL) in an experimental model eye. Eight study groups were treated at different energy levels ranging from 5 to 15 microJ. All treatments were done at least three times in different latex capsules and lenses. An atomic force microscope was used to measure IOL damage and an interferometric surface analysis microscope to assess the polishing effect on the PCF. The IOLs were further subjected to a scatter analysis to assess the optical significance of the damage produced. RESULTS: The latex PCF revealed a polishing effect with all energy settings used. The IOLs were damaged with all energy settings but 5 microJ. Energy settings higher than 5 microJ caused significantly more polishing effect to the latex and damage to the lenses. At the 10 microJ energy level, a single parameter with no depth produced a relative polishing depth of 3.01 microns +/- 0.10 (root mean square +/- SD). At this energy, the damage to the IOLs was 188 +/- 20.52 nm, and it was associated with typical craters over the surface at regular intervals that corresponded to each individual laser pulse. CONCLUSION: This model documented the feasibility of achieving micron-level precision in excising material with the picosecond laser and showed that posterior capsule polishing should be feasible and safe in human eyes.