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Radiosurgical Techniques
Published in Jeffrey A Sherman, Oral Radiosurgery, 2020
An operculum is an overgrowth of dense fibrous tissue, usually covering the distal portion of the occlusal surface of a newly erupted, mandibular, third molar. Inflammation of this tissue is often seen due to either masticatory trauma from the opposing arch or inflammation caused by bacteria and debris being trapped below the surface. An operculectomy is the surgical removal of the operculum as a means of preventing the development of an acute pericoronitis.
Surgical treatment of macular holes
Published in A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha, Vitreoretinal Surgical Techniques, 2019
Kamal Kishore, Gholam A Peyman
Stage 3 is characterized by a fully developed macular hole, but without complete PVD. The mean visual acuity is 20/200, with a range from 20/40 to 5/200. The hole is a round sharply defined defect measuring 400–600μm, with a surrounding halo giving the appearance of subretinal fluid. The retina near the margin of the hole may show micro-cystic changes. An ‘operculum’ is usually seen anterior to the hole. The patient may describe metamorphopsia or decreased vision due to a central scotoma. A gap in a narrow-slit beam (positive Watzke–Allen test) is generally considered pathognomonic of a full-thickness macular hole, but was observed in only 15 of 40 eyes with a full-thickness macular hole documented by OCT.24 A scotoma is demonstrated within the hole in virtually 100% of patients using a 50-μm aiming beam of an argon or krypton laser.11 Microperimetry with a scanning laser ophthalmoscope (SLO) may also reliably document a dense scotoma corresponding to the macular hole, and may help differentiate true macular holes from pseudoholes.25
Fasciola
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Fasciola spp. utilize freshwater amphibious snails of the family Lymnaeidae as intermediate hosts. The lymnaeid snails with the capacity of serving as natural or experimental intermediate hosts for F. hepatica include Austropeplea tomentosa, Austropeplea ollula, Austropeplea viridis, Fossaria bulimoides, Lymnaea bulimoides (North America), Lymnaea columella (Americas), Lymnaea cousini, Lymnaea cubensis, Lymnaea diaphana (South America), Lymnaea humilis, Lymnaea neotropica (Uruguay), Lymnaea occulta, Lymnaea stagnalis, Lymnaea tomentosa (Australia), Lymnaea (Galba) truncatula (most continents), Lymnaea viator (South America), Lymnaea viatrix, Lymnaea viridis (China), Omphiscola glabra, Pseudosuccinea columella, Radix auricularia, Radix lagotis, Radix natalensis, Radix peregra, Radix rubiginosa, Stagnicola caperata, Stagnicola fuscus, Stagnicola palustris, and Stagnicola turricula [14]. These snails are pulmonate (with lungs) and small (0.5–2.5 cm long), with thin fragile shells, without an operculum (lid), but having the apertures on the right-hand side (dextral) [15,16].
Impacts of ingested MWCNT-Embedded nanocomposites in Japanese medaka (Oryzias latipes)
Published in Nanotoxicology, 2021
Melissa Chernick, Alan Kennedy, Treye Thomas, Keana C. K. Scott, Christine Ogilvie Hendren, Mark R. Wiesner, David E. Hinton
Six fish (3 females, 3 males) in each group were processed for histology. Immediately following euthanasia, a disposable extended length fine tip pipette was inserted into the buccal cavity and 10% neutral buffered formalin (10% NBF; VWR) was flushed into a branchial cavity, pharynx, and foregut. Next, microdissection scissors (Ted Pella, Redding, CA) were used to make a ventral incision from the anus to near the pectoral girdle. In order to facilitate the fixation of deep tissues, the pipette was used to gently flush the fixative into the abdominal cavity, making sure to not displace internal organs. Next, specimens were immersed in 10 times volume of 10% NBF and fixed overnight on an orbital shaker at room temperature. Then, one male per treatment group was prepared for transverse sectioning by cutting two crosswise portions. The first portion consisted of the head to just past the operculum, with the second ending just caudally to the abdomen. Cut portions were returned to fixative. All fixed specimens were stored at 4 °C until processing.
Vitreomacular disorders: a review of the classification, pathogenesis and treatment paradigms including new surgical techniques
Published in Clinical and Experimental Optometry, 2021
Mali Okada, Daniel Chiu, Jonathan Yeoh
Vitreomacular traction is the result of anomalous PVD with anteroposterior traction of the vitreous at its attachment to the fovea.9 If the force is excessive, it can lead to distortion of the macular architecture, with intraretinal pseudocyst formation, intraretinal schisis or even elevation of the fovea from the retinal pigment epithelium (RPE), or foveal detachment.6 A similar process is thought to occur in the development of a full-thickness macular hole (FTMH). Progressive traction at the fovea results in complete interruption of all neural layers due to dehiscence of the foveal pseudocyst and/or breakdown of the elevated outer retina. Although the causative force on the retina is usually in an anteroposterior direction, once an FTMH is formed, tangential traction from contraction of the residual ILM at the hole edge may also cause the hole to enlarge.10 In some cases an operculum may be visible overlying the foveal defect, consisting of both glial and neuroretinal tissue.11
The Drosophila foraging gene plays a vital role at the start of metamorphosis for subsequent adult emergence
Published in Journal of Neurogenetics, 2021
Ina Anreiter, Aaron M. Allen, Oscar E. Vasquez, Lydia To, Scott J. Douglas, Javier V. Alvarez, John Ewer, Marla B. Sokolowski
Animals that had recently pupariated were examined and those containing a bubble in the midregion of the puparium (late-stage P4(i); Bainbridge & Bownes, 1981) were selected. For low-resolution video recordings of pupation, 2 rows of 10–15 animals (one of mutant animals and the other of controls) were placed on a microscope slide on double-sticky tape and the operculum was removed. The slide with pupae was then placed in a humidified Petri dish and the animals were video recorded at room temperature (ca. 22 °C) under dim transmitted light using a Leica DMLB microscope (10x magnification). For higher resolution imaging (cf. Videos 1 and 2), animals were mounted using double-stick tape on a plexiglass disc mounted on a motor that turned 5 times per hour. The operculum was then removed, and animals were covered with a large Petri dish and kept humidified using a damp piece of paper towel. The disc was then mounted under a Leica DMLB dissection microscope and images captured every time an animal entered the field of view. Matlab-based custom-made software was then used to reconstruct the time sequence of emergence behaviors for each animal. Timing and duration of the following behaviors were scored: head inflations (HIs), operculum opening (OP), and adult emergence (AE).