TY - JOUR. T1 - Detection of Bacterial Endosymbionts in Clinical Acanthamoeba Isolates. AU - Iovieno, Alfonso. AU - Ledee, Dolena R.. AU - Miller, Darlene. AU - Alfonso, Eduardo C. PY - 2010/3/1. Y1 - 2010/3/1. N2 - Purpose: To determine the presence of 4 clinically relevant bacterial endosymbionts in Acanthamoeba isolates obtained from patients with Acanthamoeba keratitis (AK) and the possible contribution of endosymbionts to the pathogenesis of AK. Design: Experimental study. Participants: Acanthamoeba isolates (N = 37) recovered from the cornea and contact lens paraphernalia of 23 patients with culture-proven AK and 1 environmental isolate. Methods: Acanthamoeba isolates were evaluated for the presence of microbial endosymbionts belonging to the bacterial genera Legionella, Pseudomonas, Mycobacterium, and Chlamydia using molecular techniques (polymerase chain reaction and sequence analysis, fluorescence in situ hybridization) and transmission electron microscopy. Corneal toxicity and ...
Purpose: To detect the genotypes of Acanthamoeba spp. isolates from patients of clinically suspected amoebic keratitis and proteomic characterisation of trophozoite and cyst stages. Methods: Corneal scrapings from clinically suspected amoebic keratitis(AK) patients (107) attending our tertiary care hospital during last 2 years were subjected to culture on 2% non- nutrient agar plates overlaid with E.coli. DNA isolation followed by PCR assay was performed for amplification of DF3 region (280bp) of 18S rRNA gene of Acanthamoeba spp.. PCR products were sequenced and aligned using software CLUSTAL W. Phylogenetic tree reconstructions was performed with phylogenetic computer program MEGA4 using neighbour-joining method as well as UPGMA anakysis. The cultured trophozoites were encysted in laboratory conditions and the whole cell lysates of both the stages were subjected to SDS-PAGE and two dimensional gel electrophoresis.. Results: Acanthamoeba spp. was isolated from 18 of the 107 (16.82%)suspected ...
The recent study, Acanthamoeba Infection market forecasts the business performance of the Acanthamoeba Infection market for the forecast period, 2019 to 2026. The study considers the estimated period as the base duration and brings to light the important information associated with the market size, share and growth rate of the Acanthamoeba Infection market.. Apart from this, the research closely examines the market share occupied by some of the prominent market players in the Acanthamoeba Infection market for the forecast period, 2019 to 2026. Researchers behind the research unmask vital statistics on market segmentation including product types, application, sale and geography.. FREE SAMPLE COPY [Customized Copy + CAGR and Gross Market Value Included] @ https://www.marketexpertz.com/sample-enquiry-form/74658. This study relies on the evolution of the industry to derive the trends that are observed. A significant increase in the global market is visible, which promises the expansion of the market ...
The Gram-negative bacterium Campylobacter jejuni is able to enter, survive and multiply within the free living amoeba Acanthamoeba polyphaga, but the molecular mechanisms behind these events are still unclear. We have studied the uptake and intracellular trafficking of viable and heat killed bacterial cells of the C. jejuni strain 81-176 in A. polyphaga. We found that viable bacteria associated with a substantially higher proportion of Acanthamoeba trophozoites than heat killed bacteria. Furthermore, the kinetics of internalization, the total number of internalized bacteria as well as the intracellular localization of internalized C. jejuni were dramatically influenced by bacterial viability. Viable bacteria were internalized at a high rate already after 1 h of co-incubation and were observed in small vacuoles tightly surrounding the bacteria. In contrast, internalization of heat killed C. jejuni was low at early time points and did not peak until 96 h. These cells were gathered in large ...
Pathogenic strains of the genus Acanthamoeba are causative agents of a serious sight-threatening infection of the eye known as Acanthamoeba keratitis. The prevalence of this infection has risen in the past 20 years, mainly due to the increase in number of contact lens wearers. In this study, the prevalence of Acanthamoeba in a risk group constituted by asymptomatic contact lens wearers from Tenerife, Canary Islands, Spain, was evaluated. Contact lenses and contact lens cases were analysed for the presence of Acanthamoeba isolates. The isolates' genotypes were also determined after rDNA sequencing. The pathogenic potential of the isolated strains was subsequently established using previously described molecular and biochemical assays, which allowed the selection of three strains with high pathogenic potential. Furthermore, the sensitivity of these isolates against two standard drugs, ciprofloxacin and chlorhexidine, was analysed. As the three selected strains were sensitive to chlorhexidine, its
Acanthamoeba spp. are microscopic organisms that can be found just about anywhere, from soil to water, to the air we breathe. They are the direct culprits of Acanthamoeba keratitis (AK) a relatively rare but sight-threatening disease which is actually caused by at least eight species of Acanthamoeba: A. castellanii, A. culbertsoni, A. polyphaga, A. hatchetti, A. rhysodes, A. lugdunesis, A. quina, and A. griffin. Ocular trauma and contaminated water are also associated with AK infections but it has been found that contact lens wearing accounts for , 80% of the cases. If found early the infection can be cured, but this gets progressively more difficult the longer it remains untreated. The difficulty lies with the life cycle of the Acanthamoeba species which consists of two stages: the trophozoite and the cyst ...
Acanthamoeba is a genus of amoebae, a single-celled eukaryote commonly recovered from soil, fresh water and other habitats. Acanthamoeba has two evolutive forms, the metabolically active trophozoite and a dormant, stress resistant cyst. Trophozoites are small, usually 15 to 35 μm in length and amoeboid in shape. In nature, Acanthamoeba species are free-living bacterivores, but in certain situations they can cause infections (Acanthamebiasis) in humans and other animals. Acanthamoeba spp. are among the most prevalent protozoa found in the environment. They are distributed worldwide, and have been isolated from soil, air, sewage, seawater, chlorinated swimming pools, domestic tap water, bottled water, dental treatment units, hospitals, air-conditioning units, and contact lens cases. Additionally, Acanthamoeba have been isolated from human skin, nasal cavities, throats, and intestines, as well as plants and other mammals. Diseases caused by Acanthamoeba include keratitis and granulomatous amoebic ...
PURPOSE: To characterize better the ameba-host interactions that may be involved with the pathogenesis of Acanthamoeba keratitis, the role of calcium (Ca2+) on the binding of Acanthamoeba polyphaga to extracellular matrix proteins was examined in vitro. METHODS: The binding of a metabolically labeled A. polyphaga (CDC:0187:1) isolate from a case of human keratitis to collagen type IV, laminin, and fibronectin was assessed through a range of calcium concentrations in the external fluid. Binding to collagen IV was studied in detail, with and without other divalent cations and calcium channel modulators. RESULTS: Calcium increased binding in a dose-dependent manner, with significant effects at 0.1 to 1.0 microM and near-maximal effects at 1 to 100 microM, depending upon the matrix protein. Magnesium alone had no effect on ameba binding to collagen IV but suppressed the action of calcium. Strontium enhanced ameba binding, with maximal effect at 100 microM. The calcium channel antagonists nifedipine ...
Another name for Acanthamoeba Infection is Acanthamoeba Infection. The evaluation of an acanthamoeba infection begins with a history and physical examination ...
Acanthamoeba myosin-II forms filaments of two different sizes. Thin bipolar filaments 7 nm wide and 200 nm long consist of 16 myosin-II molecules. Thick bipolar filaments of variable width (14-19 nm) consist of 40 or more myosin-II molecules. Both have a central bare zone 90 nm long and myosin heads projecting laterally at the ends. The heads are arranged in rows spaced 15 nm apart. In the case of the thin myosin-II filaments there are two molecules per row. The thick filaments are formed rapidly and reversibly in the presence of 6-10 mM MgCl2 (or any of five other different divalent cations tested) by the lateral aggregation of thin myosin-II filaments. Acid pH also favors thick filament formation. Neither the myosin-II concentration (50-1,000 micrograms/ml) nor ATP has an effect on the morphology of the filaments. The polymerization mechanism was studied quantitatively by measuring the amount of polymer formed (Cp) under various conditions as a function of total myosin-II concentration (Ct). ...
Abstract: The free-living amoebae of the genus Acanthamoeba are widely distributed in nature and are considered potentially pathogenic organisms. Occasionally they can trigger human infections such as granulomatous amoebic encephalitis and amoebic keratitis. The investigation of differentiating characteristics between pathogenic strains and those not associated with infection may help to determine factors related to pathogenicity and the development of diagnostic tests. In this sense, the aim of this study was to perform a comparative evaluation; by means of physiological, morphological and immunochemical criteria; between clinical and environmental samples of Acanthamoeba. Trophozoites of four isolates were used: a clinical sample, obtained from a confirmed case of amoebic keratitis; an environmental sample, obtained from the dust of the residence of the same patient; and two reference samples A. poliphaga #2, obtained from an amoebic keratitis (ATCC 30641) and A. poliphaga #4, obtained from ...
Acanthamoeba sp. ATCC ® PRA-219™ Designation: UWC1/UV-7 Isolation: Acanthamoeba sp. UWC1 coincubated with activated sludge. Plattling, Bavaria, Germany.
TY - JOUR. T1 - Drug target identification, validation, characterisation and exploitation for treatment of Acanthamoeba (species) infections. AU - Roberts, Craig W.. AU - Henriquez, Fiona L.. N1 - Special Issue - Biology and Pathogenecity of Free-Living Amoebae. Compiled after the XIIIth International Meeting on the Biology and Pathogenicity of Free-Living Amoebae, FLAM 2009, Tenerife, Spain. PY - 2010/9. Y1 - 2010/9. N2 - New more efficacious antimicrobials as required for the treatment of Acanthamoeba infections as those currently available require arduous treatment regimes, are not always effective and are poorly active against the cystic stages. Herein, we review potential drug targets including tubulin, alternative oxidase, amino acid biosynthesis and myosin. In addition, we review the literature for current missing tools and resources for the identification, validation and development of new antimicrobials for this organism. Additional targets should come to light through a concerted ...
Acanthamoeba infection of the eye is it contagious? Contagiousness of Acanthamoeba infection of the eye including infectiousness, transmission, and contagion methods and vectors.
New tool for the simultaneous detection of ten different genotypes of Acanthamoeba available from the American Type Culture Collection. Background: Acanthamoeba keratitis (AK) is a sight-threatening infection and none of the current diagnosis tests are able to detect in one reaction low levels of the vast majority of strains associated with pathology. The goal of this work was to validate a new tool for the detection of the American Type Cell Collection referenced Acanthamoeba monitoring simultaneously DNA extraction yields and PCR inhibitors. Performances were assessed on corneal scrapings.. Methods: Primers were selected in a region bracketing a 41591 bp of the A. castellanii mitochondrion gene. DNA extraction and PCR inhibitors were monitored by adding an internal control (virus). Acanthamoeba were detected and quantified by the real time fast duplex TaqMan® PCR (f-d-real-t PCR) and negativity confirmed by SYBR Green real time PCR.. Results: The f-d-real-t PCR detects 0.1 cyst/µl or less of ...
1. Adl, S. M., Simpson, A. G. B., Farmer, M. A., Andersen, R. A. et al. The new higher level classification of eukaryotes with emphasis on the taxonomy of protists. J. Eukaryot. Microbiol., 2005, 52, p. 399-451. 2. Aichelburg, A. C., Walochnik, J., Assadian, O., Prosch, H. et al. Successful treatment of disseminated Acanthamoeba sp. infection with miltefosine. Emerg. Infect. Dis., 2008, 14, p. 1743-1746. 3. Booton, G. C., Visvesvara, G. S., Byers, T. J., Kelly, D. J. et al. Identification and distribution of Acanthamoeba species genotypes associated with nonkeratitis infections. J. Clin. Microbiol., 2005, 43, p. 1689-693. 4. Cengiz, A. M., Harmis, N., Stapleton, F. Co-incubation of Acanthamoeba castellanii with strains of Pseudomonas aeruginosa alters the survival of amoeba. Clin. Exp. Ophthalmol., 2000, 28, p. 191-193. 5. Chatton, E. Classe des Lobosa Leidy, 1879. Ordre des amoebiens nus ou Amoebaea. In Grassé, P. P. Traité de zoologie, anatomie, systématique, biologie. Tome I. Protozoaires. ...
There are three main genera of free living amoeba that infect humans - Acanthamoeba, Balamuthia, Naegleria that are are important causes of disease in humans and animals. The topic for todays podcast will be one of them- Acanthamoeba.. Acanthamoeba is a microscopic, free-living amoeba that can cause rare, but severe infections of the eye, skin, and central nervous system.. Joining me to talk about Acanthamoeba is Parasitology teacher and author of Parasites: Tales of Humanitys Most Unwelcome Guests, Rosemary Drisdelle.. ...
This study aimed to detect the presence of Acanthamoeba spp. in different water resources of Zahedan, southeast of Iran, and also systematically reviewed all publications regarding Acanthamoeba in Iran (2005-2018). Fifty water samples were collected from different water resources in Zahedan. The positive samples were identified morphologically and subjected to polymerase chain reaction (PCR) using...
The water supply and dust samples from the home environment (bathrooms and kitchens) of 50 wearers of contact lenses (CLs) were cultured for the presence of free-living amoebae. CL cases, solutions, and water taps were cultured for bacteria, which amoebae require for growth. Acanthamoeba spp were isolated from water drawn from six bathroom cold water taps (tank supplied), five in the presence of limescale, and from one kitchen cold water tap (mains supplied). There was an association between the presence of limescale in water and direct culture for free-living amoebae, suggesting that scale provides a favourable microenvironment for amoebae. Acanthamoebae were also found in dust from around one washbasin. Nineteen of 50 CL cases, 12/122 CL care rinsing solutions, and 59/100 cold water taps yielded Gram negative bacteria which could be ingested by amoebae. It is concluded from this study that CLs should not be washed in first-drawn tank-fed cold water, especially if limescale is present, and that ...
Acanthamoebiasis is most often found in patients with immune deficiency, with infections facilitated by the intake of immunosuppressive drugs. The host immune response to Acanthamoeba spp. infection is poorly understood. Thus, in this study, we aimed to examine the course of Acanthamoeba spp. infection taking into account the hosts immunological status, including assessment of the hematological parameters, cytokine analysis, immunophenotypic changes in spleen populations, and histological spleen changes, which could help clarify some aspects of the immune response to acanthamoebiasis. In our experimental study, we used Acanthamoeba strain AM 22 isolated from the bronchoaspirate of a patient with acute myeloid leukaemia (AML) and atypical pneumonia symptoms. Acanthamoeba spp. affected the hematological parameters in immunocompetent and immunosuppressed mice and induced a change in spleen weight during infection. Moreover, analysis of anti-inflammatory (IL-4 and IL-10) and pro-inflammatory (IL-17A and
Acanthamoeba hatchetti ATCC ® PRA-114™ Designation: 3ST Isolation: clinical specimen - human Vienna Austria Isolation date: 1997
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تعالى نفصصهم تاني … المرض الأول اسمه Acanthamoeba keratitis: وده بيعمل التهاب في قرنيه العين وده عامل كانه سدلك العدسة اللى بتصور بيها يعنى ممكن يسبب العمى.. المرض التاني Granulomatous Amebic Encephalitis: وده بيعمل التهاب في المخ والحبل الشوكي وده معناه انه ممكن يقتل رئيس دولتك يعنى يموت المخ والحبل الشوكي وده معناه انهيار الدولة كلها يعنى يؤدي للموت. المرض التالت واسمه disseminated infection: وده ذي ما قولنا عامل ذي الغزو بينتشر في كل حتة وبيعمل التهابات في كل حتة.. You can say "This means that it is dangerous and can kill me and can attack me at any moment and you told me that this enemy lives everywhere… this is scary".. No, dont worry. It is rare to attack you because it is a weak ...
Virology Highlights features highlighted articles published in Virology, with posts summarizing the research in the authors words.
We have studied the kinetics of the gelation process that occurs upon warming cold extracts of Acanthamoeba using a low-shear falling ball assay. We find that the reaction has at least two steps, requires 0.5 mM ATP and 1.5 mM MgCl2, and is inhibited by micromolar Ca++. The optimum pH is 7.0 and temperature, 25 degrees-30 degrees C. The rate of the reaction is increased by cold preincubation with both MgCl2 and ATP. Nonhydrolyzable analogues of ATP will not substitute for ATP either in this "potentiation reaction" or in the gelation process. Either of two purified or any one of four partially purified Acanthamoeba proteins will cross-link purified actin to form a gel, but none can account for the dependence of the reaction in the crude extract on Mg-ATP or its regulation by Ca++. This suggests that the extract contains, in addition to actin-cross-linking proteins, factors dependent on Mg-ATP and Ca++ that regulate the gelation process. ...
Learn about Castellani Paint Colorless effects, symptoms, what is, Phenol Topical treatment, mechanism of action and formula. Important information I should know about Castellani Paint Colorless, Phenol Topical effects, symptoms and treatment.
A species of motile, unicellular eukaryotic amoebae within the family of Acanthamoebidae. A. quina is placed in morphological group II with a 18s rRNA gene sequence type of T4. Members of this group are characterized by the presence of wrinkled ectocysts and endocysts which could be stellate, polygonal, triangular, or oval. This species is a human pathogen and may cause granulomatous amoebic encephalitis and amoebic keratitis.
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THE NEWS: PhRMA names new president, CEO. For the full story, click here). PhRMAs new president and CEO, John Castellani, doesnt have the political background of Tauzin, former Democratic congressman from Louisiana, but he has something pretty close in the form of a nine-year career as leader of the Business Roundtable, an influential lobbying group of corporate chief executives from various industries.. And it appears PhRMA made a wise choice. Politico quoted an unnamed senior industry official as saying the lobby sought a "non-partisan, manager type" to head the group while pointing out his relationships with members of Congress in both major parties. David Brennan, head of the organizations search committee and president and CEO of AstraZeneca, pointed out Castellanis experience in coalition building and "strong reputation of working across the political divide.". ...
Hi, I am using QIAamp kit to extract DNA from Acanthamoeba culture. However, I just able to extract about 40ng/ul of concentration only when measured by NanoQuant. Is this concentration normal for Acanthamoeba ? This is because previously extraction from other sample can obtain high concentration up to 300ng/ul. Or is there any pre-treatment required to be done to the sample before using this Qiagen kit? I am sure there is no other step stated in Qiagen handbook, just that any other step that is specifically to acanthamoeba ...
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A Linwood man seriously injured in an arrest outside the Tropicana Atlantic City in 2013, requiring hundreds of stitches to repair bites by a police dog, has settled an excessive force lawsuit against Atlantic City for $3 million, his attorney confirmed Sunday.. ...
In 1980, Tim Rowbotham, a microbiologist at the University of Bradford, made an extraordinary discovery about a tiny single-celled protozoa called Acanthamoeba. These organisms are ubiquitous, turning up almost anywhere there is liquid water. Since the 1950s they have been known to cause a number of rare diseases, mainly in humans with impaired immune systems.…
... +++++ Para ilmuwan menyatakan bahwa jenis parasit Acanthamoeba yang terdapat pada debu, air l
Volume 14, Issue 1, January 2014, Pages: 184-192, C. Castellani, A. Angelini, O. J. de Boer, C. M. van der Loos, M. Fedrigo, A. C. Frigo, L. B. Meijer-Jorna, X. Li, H. J. P. Ploegmakers, F. Tona, G. Feltrin, G. Gerosa, M. Valente, G. Thiene and A. C. van der Wal. Version of Record online : 4 DEC 2013, DOI: 10.1111/ajt.12517 ...
Martins work is focused on the creation of tools and pipelines for the processing of human data at the Sanger Institute and elsewhere. His PhD research project is centred on exploring genomic variation within Africa with a special interest in the HLA.
Define Acanthamoeba polyphaga mimivirus. Acanthamoeba polyphaga mimivirus synonyms, Acanthamoeba polyphaga mimivirus pronunciation, Acanthamoeba polyphaga mimivirus translation, English dictionary definition of Acanthamoeba polyphaga mimivirus. n. pl. mim·i·vi·rus·es Any of a genus of double-stranded DNA viruses that are the largest of all known viruses. n a very large virus containing DNA
During January 2010, a husband and wife returned from Laos to France with probable parasitic disease. Increased antibodies against an Acanthamoeba polyphaga mimivirus virophage indicated seroconversion. While in Laos, they had eaten raw fish, a potential source of the virophage. This virophage, associated with giant viruses suspected to cause pneumonia, could be an emerging pathogen.
We present eight cases of Acanthamoeba keratitis. In each case; the Acanthamoeba organisms were visualized in the epithelium and anterior stroma using tandem scanning confocal microscopy. The organisms were highly reflective, ovoid, and were 10-25 microns in diameter. The Acanthamoeba organisms in the human corneas were identical in size and shape to Acanthamoeba organisms on an agar plate visualized with the same confocal microscope. Confocal microscopy is a useful method for identifying Acanthamoeba organisms in vivo within the corneal epithelium and anterior stroma.
In the present study, three artificial tear brands were selected according to the preservative agents (detergent or oxidative) or the lack of them to study their possible amoebicidal activity against trophozoites, as this is the initial state of the infection.. To study the viability of Acanthamoeba trophozoites after incubation with these tears, two different methods were used. The more traditional one, Trypan Blue stain, allows the differentiation of amoebae with the altered cell membrane and thus, identification of the non-viable ones. The second method used CTC stain to measure mitochondrial activity to determine the viability of the amoebae. This stain was developed for bacterial viability and then, adapted for Acanthamoeba in fluorometry by Kobayashi et al. [23]. In the present study, CTC stain for Acanthamoeba viability was used with flow cytometry for the first time.. One of the artificial tears tested using these two methods was Optava Fusion™. It contains Purite®, which is a soft ...
Acanthamoeba Keratitis is a devastating eye infection which in developed countries most commonly occurs in contact lens wearers. Consultant Ophthalmologist Deepa Anijeet will summarise key concepts such as risk factors, diagnosis and treatment of Acanthamoeba Keratitis. It will also highlight key areas of research that offer hope for sufferers.
Acanthamoeba are tiny amoeba like parasites found in water sources such as tap water, well water, hot tubs and soil or sewage systems. Eye infections can occur when contact is made with these parasites and is usually due to the improper care of contact lenses or unhygienic conditions.. Recent outbreaks of acanthamoeba infections have been noted by the Centers for Disease Control and Prevention throughout the U.S. The use of contact lens solutions that were contaminated during the manufacturing process led to an outbreak in 2007.. The good news is that with proper contact lens care, most cases can be avoided and that contact lens solutions undergo rigorous testing to ensure a sterile products reaches market.. ...
Acanthamoeba keratitis (AK) is a serious, debilitating, and intensely painful infection of the cornea caused by parasites of the genus Acanthamoeba. At present,...
Acanthamoeba is a pathogen frequently infecting brain, eyes, skin and lung of human and animal. Seven Acanthamoeba local isolates from various sources, two Acanthamoeba type strains and one strain of Hartmannella vermiformis were characterized for their genetic variability using randomly amplified polymorphic DNA (RAPD) technique using four different 10-mer oligonucleotides primers. Electrophoresis of the amplification products generated DNA bands ranging from approximately 0.25 to 7.50 kbp in size. A genetic relatedness among the isolates was examined using Dice similarity coefficient as the genetic distance measured between the strains of Acanthamoeba and H. vermiformis. Three distinct clusters could be separated at genetic distance of approximately 0.330. © 2006 Asian Network for Scientific Information. ...
Campylobacter jejuni is the leading bacterial cause of gastrointestinal diarrheal disease in humans worldwide. This zoonotic pathogen has a complex epidemiology due to its presence in many different host organisms. The overall aim of this thesis was to explore the role of amoebae of the genus Acanthamoeba as an intermediate host and vector for survival and dissemination of C. jejuni. Earlier studies have shown that C. jejuni can enter, survive and replicate within Acanthamoebae spp. In this thesis, I have shown that C. jejuni actively invades Acanthamoeba polyphaga. Once inside, C. jejuni could survive within the amoebae by avoiding localization to degradative lysosomes. We also found that A. polyphaga could protect C. jejuni in acid environments with pH levels far below the range in which the bacterium normally survives. Furthermore, low pH triggered C. jejuni motility and invasion of A. polyphaga. In an applied study I found that A. polyphaga also could increase the survival of C. jejuni in ...
... may be limited to the epithelium in its early stages, resulting in epithelial dendrites and punctate epitheliopathy. Later stromal involvement classically results in a partial or complete paracentral ring infiltrate as seen in this photograph. The many amoeba visible on the confocal microscopy image confirmed the suspected etiology to this patients infiltrate.
Purpose. To report a case of medication-resistant acanthamoeba keratitis (AK) treated successfully by corneal crosslinking (CXL). Methods. A 26-year-old male with medication-resistant AK underwent a standard CXL procedure with local anesthesia, follo
A. castellanii is a ubiquitous organism, found in many ecosystems worldwide. It is able to survive in harsh environmental circumstances - even in some contact lens solutions - and this is not the first occurrence of A. castellanii appearing in the eye. Acanthamoeba keratitis (AK) is a neglected malady frequently associated with contact lens wear.. Acanthamoeba infection of the cornea causes severe inflammation, intense pain and impaired vision, which is blinding if left untreated. Infection begins when the parasite is at its active feeding trophozoite stage and sticks to the corneal tissue before penetrating the lower stromal layer. The resulting opacity leads to less sharp vision and eventually blindness.. Acanthamoeba infections (not just in the eye) are being detected by clinicians with increasing frequency, especially as opportunistic infections in patients whose immune system is already compromised. This at-risk population is expanding as a result of increasing use of immune-suppressing ...
Mimivirus. Transmission electron micrograph (TEM) of Acanthamoeba polyphaga mimivirus (APMV) particles. APMV is commonly known as the mimivirus. This virus consists of outer hairs, or fibrils (spikes), and a protein capsid (dark grey) enclosing a core (black) of DNA (deoxyribonucleic acid), the virus genetic material. APMVs classification as a pathogen is tentative, but it is now thought that it may cause viral pneumonia. Magnification: x9,300 when printed 10 centimetres wide. - Stock Image C001/4438
The role played by soluble molecules that may participate in acanthamoebal cytopathogenicity has yet to be fully characterized. We demonstrate here that Acanthamoeba castellanii trophozoites constitutively release ADP in the medium. Cell-free supernatants prepared from A. castellanii, by interaction with specific P2y2 purinoceptors expressed on the Wish cell membrane, caused a biphasic rise in [Ca2+]i, extensive cell membrane blebbing, cytoskeletal disorganization, and the breakdown of nuclei. Cell damage induced by amoebic supernatants was blocked by the P2y2 inhibitor Suramin. The same results were found in Wish cells exposed to purified ADP. These findings suggest that pathogenic free-living A. castellanii may have a cytopathic effect on human epithelial cells through ADP release, by a process that begins with a rise of cytosolic free-calcium concentration, and culminates in apoptosis. ...